Welcome to visit Acta Energiae Solaris Sinica, Today is

Current Issue

  • Select all
    |
  • Wang Weishu, Qin Yuhong, Wang Yuefeng, Gao Songping, Guo Shugang
    PDF ( )   Knowledge map   Save
    This study focuses on walnut shell(WS) and vinegar residue (VR) as research subjects, investigating the effects of torrefaction pretreatment on biomass ash fusion characteristics in both CO2 and N2 atmospheres within a fixed-bed reactor. Chemical fractionation and inductively coupled plasma mass spectrometry (ICP-MS) were adopted to quantify the occurrence modes and contents of AAEMs, respectively. The results reveal that compared with N₂ atmosphere, torrefaction under CO₂ atmosphere elevates the mass loss rate and ash yield of biomass, and significantly increases four ash melting characteristic temperatures of torrefied biomass, namely deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT) and flow temperature (FT). At the torrefaction temperature of 300 ℃ under CO₂ atmosphere, the ST of WS ash rises by 251 ℃, while the ST of VR ash increases by 117 ℃. Chemical fractionation results demonstrate that CO₂ atmosphere facilitates the growth of HCl-soluble and insoluble AAEM fractions in torrefied biomass. Further X-ray diffraction (XRD) characterization verifies the rise in relative content of high-melting-point alkaline earth metal aluminosilicates in ash. In summary, torrefaction in CO₂ atmosphere can more effectively mitigate ash deposition and slagging during biomass thermal conversion.
  • Lu Guoqiang, Feng Jiajun, Xiang Xia’nan, He Chunhui, Yang Liu, Dai Qi
    PDF ( )   Knowledge map   Save
    This study investigates the biomass and coal composite serial gasification process using the Computational Particle Fluid Dynamics (CPFD) method to develop a comprehensive model. The model accounts for flow behavior, particle dynamics, heat and mass transfer, as well as both homogeneous and heterogeneous chemical reactions within the gasifier. A parametric analysis is conducted to evaluate the effects of gasification temperature, steam-to-biomass ratio (SBR), biomass-to-coal ratio (BCR), and biomass particle size on the syngas composition, gas yield, and overall gasification efficiency. Results indicate that higher gasification temperatures enhance gasification performance, although furnace turbulence effects must be considered. Different SBR lead to distinct reaction mechanisms: low SBR favors gas-solid reactions in the dense phase, whereas high SBR enhances homogeneous reactions near the outlet. A higher BCR is recommended to improve efficiency. Furthermore, performance varies little across different biomass raw materials, indicating that the proposed process allows for flexible raw materials substitution.
  • Zhang Zhitao, Zhang Shuanglin, Li Wen, Yang Shuquan
    PDF ( )   Knowledge map   Save
    Design a dual active sites system of K2CO3 and P2O5 as active sites, using over-dried bamboo powder as the supporting additive, and prepare the supported carbon fixative via a rotary evaporation method. Subsequently, we investigate the effect of this carbon fixative on biomass pyrolysis is investigated. Experimental results exhibit that the addition of the carbon fixative increases the solid residue yield during bamboo powder pyrolysis from 49.7% to 53.1%, while the calorific value of the carbon products remains unaffected. Characterization data confirm that the carbon fixation of the material is attributed to its unique three-dimensional network structure, which promotes the secondary pyrolysis of pyrolysis gas and thereby enhances the solid residue yield. Meanwhile, the ash content of bamboo charcoal slightly increases from 0.86% to 0.96% after adding the carbon fixative, demonstrating no significant impact on charcoal combustion characteristics.
  • Wang Dazhi, Zhao Yongqing, Suo Liujia, Zhu Li, Wu Feng
    PDF ( )   Knowledge map   Save
    The significant randomness of the effective wave height of ocean waves makes it difficult to meet the actual demand for high-precision prediction. A novel method for predicting effective wave height based on a fusion model combining the fast Fourier transform (FFT) with a multi-head axial attention mechanism (FFT-MaxVIT) is proposed in this paper. Firstly, the fast Fourier transform (FFT) is employed to accentuate the dominant frequency components of the waves while suppressing noise interference. secondly, specifically addressing scenarios involving small data samples, the model utilizes convolutional layers to extract local features; concurrently, it leverages both block attention and grid attention mechanisms to efficiently extract global features while effectively reducing computational complexity. Finally, pruning techniques and Bayesian optimization algorithms are applied to fine-tune the model parameters, thereby efficiently identifying the optimal combination of hyperparameters. The experimental evaluation involved two stages: first, a comparative analysis was conducted to assess the impact of applying the FFT; second, the predictive performance of the proposed model was benchmarked against that of several established models, including the long short-term memory network (LSTM), the residual network(ResNet), and the Vision Transformer (ViT). The experimental results demonstrate that the proposed model effectively enhances the prediction accuracy of effective wave height.
  • Jiang Chao, Wu Jiale, Li Chao, Xu Jiamin, Wang Jiachen, Guan Yanling
    PDF ( )   Knowledge map   Save
    The deep-buried closed-loop geothermal heat transfer system is a primary form of utilizing geothermal energy from the middle and deep layers of the Earth. The heat transfer efficiency of the system is comprehensively influenced by the depth of buried pipes, as well as the energy consumption of water pumps and heat pumps. This study, based on a sleeve-type deep-buried pipe heat transfer project in Xi’an, established three-dimensional full-scale numerical models for pipes buried at depths of 2039, 2539, 3039, and 3539 m. The models simulated heat extraction from the buried pipes and the energy consumption of water pumps and heat pumps over 121 days. The investigation aims to explore the comprehensive heat transfer performance of deep-buried pipes. The results indicate that considering pump consumption, the comprehensive heat transfer intensity of buried pipes shows an approximate linear increasing trend with depth, and the maximum difference with the net heat transfer power of buried pipes does not exceed 1.5%.
  • Zhao Jun, Zhang Hanwen, Peng Peng
    PDF ( )   Knowledge map   Save
    To address the clogging issue caused by microbial activity in stratified soils during water source heat pump reinjection, this study utilized sand with varying particle sizes as porous media, employing Escherichia coli (E. coli) as a tracer to investigate microbial migration-deposition characteristics. One-dimensional sand column experiments were conducted to analyze breakthrough curves and migration-deposition patterns of microorganisms in stratified soils. The indoor test results demonstrate:1) In heterogeneous porous media, E. coli primarily deposits in surface layers, with its concentration decreasing progressively with increasing migration distance. Lower media permeability (or smaller particle sizes) causes deposition zones to shift closer to the surface. 2) Stratified configurations have a significant impact on bacterial migration. A sequence of overlying coarse-grained layers and underlying fine-grained layers causes the peak time of the bacteria in the effluent to shift forward. 3) Simulation of the microbial clogging mechanism reveals that experimental data on temporal variation of permeability coefficient decay exhibit good consistency with theoretical predictions. This research provides theoretical foundations for enhancing reinjection efficiency in water source heat pump systems.
  • Shi Zhenglu, Xu Jiazhu, He Yang, Hu Hao
    PDF ( )   Knowledge map   Save
    To ensure the safe and reliable operation of lithium-ion batteries (LIBs), a risk assessment method is proposed based on variable weight theory combined with the cloud model. Firstly, a comprehensive evaluation index system incorporating multiple decision factors is established by integrating various operational risk factors of LIBs, enabling holistic and objective assessment of their operational status. Subsequently, moment estimation and variable weight theory are employed to dynamically integrate and adjust the subjective and objective weights of each indicator, resulting in more reliable and precise weight coefficients. Furthermore, cloud model is adopted to conduct risk assessment and determine the risk level of LIBs operation. Finally, simulation analyses using both the proposed method and conventional approaches are performed on five LIBs from an energy storage station under different operating conditions. Results indicate that the proposed method achieves accurate operational risk assessment for LIBs.
  • Ma Youjie, Yan Fengxiang, Zhou Xuesong, Tao Long, Wang Xinyue, Chen Yunfei
    PDF ( )   Knowledge map   Save
    To address the output disturbance issue of new power systems under multiple uncertainties, such as the integration of new energy sources and the spatiotemporal distribution of loads, this paper proposes A refactoring linear active disturbance rejection control strategy (TD3-R_LADRC) based on the twin delayed deep deterministic policy gradient (TD3) algorithm. The objective is to enhance the ability of energy storage systems to mitigate DC bus voltage fluctuations. Firstly, the disturbance differential in the extended state observer (ESO) is observed, and the ESO is reduced in order This enables faster and more precise tracking and compensation of total disturbance factors in the system, effectively improving the response speed and accuracy of controllers. Subsequently, frequency domain performance and stability analysis are conducted on the proposed improved strategy. To further tap into the performance potential of this strategy, this study introduces the TD3 reinforcement learning algorithm and performs intelligent optimization training on key parameters of the improved LADRC, including observer bandwidth and controller bandwidth. Finally, through digital simulation and low-power experiments, this study conducts a comparative analysis of the improved controller, traditional linear active disturbance rejection control, and the dual closed-loop PI control strategy in terms of disturbance rejection, stability, and robustness under different operating conditions. The results demonstrate that the proposed TD3-R_LADRC strategy exhibits better control performance when facing the uncertainty of new energy output, load fluctuations and external disturbances. It can effectively enhance system robustness, improve the control effect of frequency stability, and has certain theoretical significance and engineering application value.
  • Wang Jifu, Liu Yunbo, Ding Zhengxin, Wang Pengzhao, Wei Jinjia, Long Jinlin
    PDF ( )   Knowledge map   Save
    This study uses rotational granulation to shape Ca-based pellets with a 2-3 mm diameter and achieves its ton-scale production. By using self-made aluminum sol and optimizing the rotational granulation process, Ca-based pellets with an atomic ratio of Fe:Mn∶Mg∶Ca=3∶3∶10∶100 and 10% Al2O3 content are obtained. Al and Mg elements are uniformly distributed, while Fe and Mn exhibit a gradient increase from the interior to the exterior. The pellets demonstrate high crushing strength, anti-sintering stability, excellent sphericity, and strong light absorptivity. After 25 carbonation/calcination cycles, the material retains an energy storage density of 1368 kJ/kg, showcasing potential for application in CSP thermochemical energy storage.
  • Wang Shiyu, Qu Xiaoli, Du Yan, Su Jianhui, Tao Xiao, Li Jinzhong, Xie Yuguang
    PDF ( )   Knowledge map   Save
    Aiming at the problem that traditional state of health (SOH) estimation algorithms cannot extract the required features during random partial charging and discharging of actual batteries, a segmented estimation method based on the initial voltage under charging state is proposed. This method extracts the features corresponding to the initial charging voltage point by analyzing the capacity increment curve of the battery, determines the optimal features and number of features based on random forest and related indicators, and uses them as the basis for segmenting the initial charging voltage of the battery. Corresponding features are used for SOH estimation in different segmentation intervals. Subsequently, transfer learning methods were used to solve the problem of insufficient data to support modeling in the actual operation of lithium batteries, using the sample transfer method TrAdaBoost.R2 improved by dynamic time warping, and the results show that the proposed method has high accuracy and reliability
  • Xu Cheng, Liu Zhao, Gu Qinqin, Sun Jiachen, Gu Yan
    PDF ( )   Knowledge map   Save
    To address the problem that the design of two-stage power conversion system (PCS) for energy storage generally emphasizes the stability of individual converters while ignoring the cascading coupling effect, which degrades system stability and triggers DC bus voltage oscillation, this paper establishes an impedance model of the DC-side ports in the two-stage PCS, investigates the influence of power magnitude and direction on port impedance characteristics, and an impedance optimization control strategy based on capacitor current observation is proposed. By reshaping the impedance models of the DC-side ports in both front-stage and rear-stage converters, this strategy reduces the resonance peak of the source converter’s output impedance and mitigates the negative impedance characteristics of the load converter’s input impedance, thereby avoiding intersections between input and output impedance magnitudes and enhancing the stable operational range of the cascaded two-stage PCS. Additionally, a state observer replaces current sensors for capacitor current measurement, reducing costs. Finally, simulations and experiments validate the effectiveness of the proposed control strategy.
  • Hou Xiaojun, Liu Xin, Hou Hongzhang, Huang Kailiang, Li Ainong, Huang Xin
    PDF ( )   Knowledge map   Save
    To achieve capacity expansion and energy efficiency in industrial waste heat utilization for district heating peak shaving, a novel peak shaving system incorporating seasonal borehole thermal energy storage (BTES) was proposed. The system synergistically combined seasonal BTES technology with conventional peak shaving methods. Outdoor temperature data from typical cities were evaluated to establish accurate heating load models. Peak shaving demand was precisely determined and optimal BTES layout was designed accordingly. An absorption heat pump was integrated to elevate the return water temperature from BTES, thereby increasing its contribution ratio. The optimal system configuration was determined through comprehensive analysis. Economic performance of different scenarios was evaluated using the annual cost method. As the results, the modified system demonstrated remarkable performance under optimal conditions. The BTES contributed 40.4% of the total peak shaving demand. During a typical heating season, the system provides 2.3×10⁴ GJ of peak shaving heat over 1845 operation hours, successfully meeting the 12.4 MW peak demand. The annual cost per unit heat extraction is 177 RMB/GJ, showing excellent economic feasibility. This system provides an efficient, low-carbon solution for district heating peak shaving in severe cold regions, with particular advantages in industrial waste heat recovery applications.
  • Liu Yitao, Gu Chunlin, Liu Xu, Zheng Shengpeng, Li Xiang
    PDF ( )   Knowledge map   Save
    This study introduces a hydrogen aging test apparatus independently developed by the China Special Equipment Inspection and Research Institute (CSEI). Using this apparatus, a 1000-hour hydrogen aging test was conducted on high-density polyethylene (HDPE), the liner material of Type Ⅳ onboard hydrogen storage cylinders, under conditions of 85 ℃ and 87.5 MPa, verifying the reliability of the test apparatus. Subsequently, hydrogen permeability tests and mechanical property tests were performed on the hydrogen-aged specimens and the control group specimens. The results show that after 1000-hour aging, the hydrogen permeation resistance of HDPE decreased slightly, increasing the risk of hydrogen accumulation, with the hydrogen permeation coefficient(Pe) increasing by 4.76%, the diffusion coefficient(D) decreasing by 3.08%, and the solubility coefficient(S) increasing by 8.10%. After 1000-hour aging, both the strength and ductility of the HDPE material increased slightly, with the average tensile strength increasing by 6.51% and the nominal elongation at break increasing by 15.33%.
  • Cui Tengfei, Li Zimu, Wang Jian, Peng Zuozhan, Cheng Ziyun
    PDF ( )   Knowledge map   Save
    To address the technical bottleneck of low efficiency and high cost in hydrogen energy storage and transportation, this study proposes a cryogenic compressed hydrogen storage system integrated with a liquid nitrogen cold shield composite insulation structure. Based on the optimized design of a 40-foot standard tank container, the system achieves a hydrogen storage capacity of 999.68 kg with a volumetric efficiency of 64 kg/m³, tripling the hydrogen loading capacity compared to traditional high-pressure tube trailers. Through hexagonal tube bundle topology optimization, 200 mm diameter is identified as the optimal tube bundle configuration. By combining liquid nitrogen cold shield (with a static evaporation rate of 0.25%/d) and high-vacuum multi-layer insulation technology, the system enables loss-free hydrogen storage for 118 days. A point-to-point transportation cost model is established to quantitatively analyze the economic performance. Results demonstrate that, under transport distances of 200-800 km and daily hydrogen supply scales of 500-1500 kg/d, the system reduces unit transportation costs by 73.2% compared to high-pressure tube trailers and achieves 54.2% lower initial investment than liquid hydrogen tankers.
  • Zhang Xiaowei, Bai Mingchuan, Su Xingyu, Zhou Jinghua
    PDF ( )   Knowledge map   Save
    To reduce frequent start-stop cycles of electrolyzers caused by renewable energy volatility and enhance system hydrogen production efficiency, a three-stage optimal operation strategy for hydrogen production units is developed, along with an improved state-of-health (SOH)-based rotation control method. A bi-level optimization strategy for renewable energy-powered water electrolysis systems is proposed and validated using real-world data from the Jibei grid. The results demonstrate that hydrogen storage and chemical energy storage can collaboratively mitigate renewable energy power fluctuations. Compared to chain-based allocation and power equalization strategies, the proposed optimized operation strategy ensures stable hydrogen system performance under fluctuating power inputs while significantly improving hydrogen production efficiency.
  • Jiang Fei, Tang Hao, Maimaiti Ellie Wupur, Hua Dong, He Guixiong, Gao Jiayuan
    PDF ( )   Knowledge map   Save
    In response to the technical challenges associated with the DC side of existing grid-connected converter systems for hydrogen fuel cells, namely insufficient boost capability, poor ripple suppression and a high risk of switching overcurrent, a three-phase, parallel quasi-Z-source, two-stage DC-boost grid-connected converter system for hydrogen fuel cells (TPPQZSTSDBHFC-GCC) is proposed. Firstly, a mathematical model of the output voltage, current and power of a proton exchange membrane hydrogen fuel cell is established, revealing its power-voltage-current output relationship and response characteristics; Secondly, based on the fuel cell’s output characteristics, the TPPQZSTSDBHFC-GCC topology is proposed, and its operating principles and features, such as ripple suppression capability, are analysed in detail. The results indicate that the proposed topology structure achieves high voltage gain while also exhibiting excellent characteristics such as low ripple, low risk of overcurrent, and good steady-state performance. The correctness and effectiveness of the proposed topology are verified through simulation and implementation.
  • Wu Liang, Lu Wenlong
    PDF ( )   Knowledge map   Save
    This paper focuses on an in-depth analysis of the coupling characteristics between PEM hydrogen production technology and photovoltaic as well as wind power. It systematically reviews the current development status and existing problems of relevant technologies, conducts a comprehensive evaluation from the perspectives of electrolyzer equipment improvement and capacity configuration, and explores the feasibility of the coupled integration of electricity-hydrogen systems. Furthermore, it analyzes the technical difficulties and economic patterns in the large-scale development of the hydrogen economy and renewable energy coupling technologies, providing development directions and solutions for the future construction of smart network architectures.
  • Jiang Jing, Sun Yiming, Guo Wenyu, Liu Fei
    PDF ( )   Knowledge map   Save
    A comprehensive energy consumption numerical model for photovoltaic glass Trombe wall was established using EnergyPlus to explore the changes in building energy consumption under the coupling effects of heat, light, and electricity during building operation. Through on-site experiments, the predictive effectiveness of the comprehensive energy consumption numerical model for heat transfer, lighting, and power generation modules will be verified. Once again, the validated comprehensive model will be combined with meteorological data from five typical cities in Northwestern China to conduct a comprehensive analysis of energy consumption and energy-saving effects. Finally, set up a blank control room to obtain the collective energy-saving effect of the photovoltaic glass Trombe wall with the best comprehensive performance. The results show that the optimal transmittance of photovoltaic glass Trombe walls in Xi’an, Lanzhou, Yinchuan, Xining, and Urumqi in the northwest region are 30%, 40%, 50%, 55%, and 60%, respectively; Compared to ordinary rooms, the energy-saving rates of the optimal energy consumption of photovoltaic glass Trombe walls are 18.4%, 21.9%, 22.7%, 21.4%, and 16.9%, respectively. The research results can provide reference for the specific application of integrated solar photovoltaic building technology in Northwestern China, and jointly promote the development of the building energy-saving industry.
  • Weng Kai, Wei Dong, Wang Chongxi, Zhang Jinbo
    PDF ( )   Knowledge map   Save
    For photovoltaic modules with early hot spots (power loss less than 25%), analyze the evolution mechanisms of occlusions, crystal defects and hidden crack type hot spot faults, establish the equivalent circuit model of the module, and utilize the I-V characteristic data obtained through detection. By calculating the key characteristic quantities (slope at short-circuit current/slope at open-circuit voltage, current at turning point) and model parameters (photogenerated current, series resistance and parallel resistance) of the I-V characteristic curves of different types of hot spots, the influence on the I-V characteristics are studied, and the difference laws among the changes of model parameters of various types of hot spots are analyzed and obtained. And the parameter changes during the evolution process from latent cracking to latent cracking type hot spots are analyzed. The research results show that the key characteristic quantities of I-V characteristics and model parameters of different types of hot spot faults have relatively obvious differences in their variation patterns, which can initially achieve the distinction and determination of three types of hot spots, as well as hidden cracks and hidden crack-type hot spots.
  • Ma Yiwei, Ma Weixing
    PDF ( )   Knowledge map   Save
    The random fluctuation characteristics of PV power are an important reason for low prediction accuracy. Therefore, this paper proposes a short-term PV power prediction method that combines PV power fluctuation features and joint optimization of SSA-GRU model. Firstly, four different PV power fluctuation feature models and an FCM-based clustering algorithm for similar power fluctuation patterns are built to obtain various input sub datasets with good distribution characteristics. Secondly, based on PV power fluctuation features, an SSA-GRU prediction model is constructed by integrating singular spectrum analysis (SSA) and gated recurrent unit (GRU), and an improved coati optimization algorithm (ICOA) is given to jointly optimize the model to fully utilize their synergistic advantages for improving PV power prediction performance. To verify the superiority of the proposed method, a comprehensive comparative experiment is conducted using data from a real PV power station in Ningxia. The results fully demonstrate that the proposed method is scientifically effective and has better predictive performance than comparative models.
  • Ye Yujiang, Xuan Shunde, Shi Ruifeng, Jia Limin
    PDF ( )   Knowledge map   Save
    To overcome the limitations of traditional methods in effectively generating long-term photovoltaic (PV) power output uncertainty scenarios, this paper proposes a novel approach that integrates an improved Transformer model with a conditional generative adversarial network (CGAN). Specifically, a Transformer-CGAN (T-CGAN) architecture is developed for generating long-term PV output scenarios. To better capture the inherent periodicity of PV output, a multi-timescale periodic attention mechanism is introduced, enabling the model to learn both short-term and long-term temporal patterns. A case study using historical data from a PV power plant in Northwest China is conducted to compare the proposed method with three benchmark models. The performance is evaluated from three perspectives: statistical accuracy, temporal correlation, and scenario validity. Experimental results demonstrate that the proposed approach significantly improves the accuracy of scenario generation, effectively captures temporal dependencies across multiple time scales, and enables efficient generation of annual PV output scenario sets.
  • Luo Wenping, Chen Zexi, Zhang Xiantao
    PDF ( )   Knowledge map   Save
    This paper classifies current high-freeboard OFPV (Offshore Floating Photovoltaic) designs as four typical pontoon-truss structures, followed by a comprehensive performance analysis. Firstly, a time-domain hydrodynamic model was established in OrcaFlex, and a dynamic power prediction model incorporating motion effects was developed using MATLAB. These models were then validated against model experiments and standard test results. Subsequently, the comprehensive performance of the four structure types was compared under static water, regular wave, and irregular wave conditions. The results demonstrate that the structure combining vertical pontoons with semi-submerged horizontal pontoons delivers superior performance, achieving a positive air gap while maintaining lower mooring forces. Parametric analysis further indicates that increasing the diameter of the horizontal pontoons significantly improves air gap performance.
  • Zhang Li, Liu Jiawei, Sun Shuyan, Zhang Tao, Zhang Hongwei
    PDF ( )   Knowledge map   Save
    To address the issues of redundant meteorological features, insufficient multi-timescale dynamic response, and lack of dynamic adaptability in ensemble forecasting methods for photovoltaic power prediction, this paper proposes an ultra-short-term prediction model based on causal feature extraction and an improved Q-L algorithm. First, a causal feature extraction method based on entropy calculation is adopted to screen key meteorological factors. This method can reflect nonlinear coupling relationships and improve feature selection quality. Second, a parallel prediction model combining a bidirectional long short-term memory network (BiLSTM) and a TCN-Transformer is constructed to capture short-term temporal fluctuations, local patterns, and long-term dependencies, achieving multi-scale feature fusion. Third, an improved Q-L algorithm with a dynamic reward-punishment mechanism is proposed to adaptively adjust the prediction weights of each model through iterative feedback and produce the final weighted prediction result. Finally, multiple simulation validations are carried out under three typical weather conditions. Comparative experimental results show that the proposed model achieves stable prediction performance. Under rainy conditions, compared with a single BiLSTM model, the ERMSE and EMAE metrics decrease by an average of 49.3% and 51.9%, respectively, indicating improved prediction accuracy and generalization ability.
  • Shi Yuezhang, Ran Maoyu, Xu Hang
    PDF ( )   Knowledge map   Save
    This study investigates the impacts of orientations on the performance of water flow cooling and power generation improvement in hollow photovoltaic (PV) window. By building two chambers with hollow PV windows, the surface temperatures and power generation with different orientations were measured during summer in Xiamen area. The research results indicate that under the same water supply flow rate, the water-cooling effect of photovoltaic Windows for cooling and power enhancement is mainly related to the solar radiation intensity and duration on the vertical surface of the window and the water supply temperature. The greater the solar radiation it receives and the longer the duration, the lower the water supply temperature, and the better the water-cooling effect for cooling and power enhancement. Also indicate that, the orientations had a significant impact on the temperature reduction of the inner and outer surfaces of the PV window. The ranking of the cooling effect is: southeast orientation (44.1%)≈east orientation(44.0%)>west orientation (41.7%)>southwest orientation(38.3%)>south orientation (36.9%). Furthermore, the orientations of the PV window have a significant impact on the daily power generation. The ranking of the percentage increase in power generation is: south orientation(34.6%)>southwest orientation (23.1%)>west orientation (16.7%)>southeast orientation(11.9%)>east orientation (6.7%). Finally, water cooling could effectively absorb the heat from window. When the water supply flow rate remains constant, the ratio of the water heat variation to the cumulative radiation is ranked as follows: south-facing > southeast-facing>west-facing≈southwest-facing≈east-facing.
  • Li Yuepeng, Yuan Zhengguo, Huang Xinyu, Xie Taihong, Xie Yi, Yu Jian
    PDF ( )   Knowledge map   Save
    This study investigates the metastable effect and ultraviolet (UV) irradiation influence on tunnel oxide passivated contact (TOPCon) solar cells through experimental methods. The results demonstrate that TOPCon solar cells exhibit a metastable effect, and the impact of UV irradiation on the cells follows a trend of initial enhancement followed by degradation. After approximately 1 s of UV pretreatment, the average power conversion efficiency (PCE) of the cells increases by 0.07%, accompanied by a 0.89 mV improvement in open-circuit voltage (Voc) and a 0.15% rise in fill factor (FF). However, prolonged UV irradiation degrades the passivation effectiveness, ultimately reducing the PCE. For the first time, this paper finds that short-time UV irradiation treatment on the cell can improve its efficiency, which lays an important foundation for the development of high-efficiency and low-cost TOPCon solar cells.
  • Li Wenhao, Wang Huipeng, He Ren, Huang Zhiping, Wei Deyuan, Xu Ying
    PDF ( )   Knowledge map   Save
    The wet etching method with a mixed solution of nitric acid, hydrofluoric acid and deionized water is employed for the first time to achieve the co-etching of the boron-and phosphorus-rich layers on the 165 mm×165 mm substrate of crystalline silicon solar cell after thermal diffusion. The optimal co-etching conditions are determined as a mixed acid volume ratio of HF∶HNO3∶H2O=1∶5∶20 and the etching time of 5 min. The co-etching also simultaneously regulates the sheet resistance of the front emitter and the back collector junctions, reduces the surface defect density, and improves the performance of crystalline silicon solar cells.
  • Li Haifang, Zhu Pengkun, Zhang Zhiyu, Xu Teng, Fan Bingbing, Li Meicheng
    PDF ( )   Knowledge map   Save
    A pulsed electric field-induced NH3 post-treatment is proposed for passivating the surface of perovskite films. Under the induction of pulsed electric fields, N atoms in NH3 molecules interact with uncoordinated Pb2+ sites in the [PbI6]4- octahedral framework on the perovskite surface, stabilizing Pb2+-related defects. Simultaneously, the pulsed electric field enhances the interaction between H atoms in NH3 and the I- ions, thereby suppressing the migration of iodine and reducing the formation of iodine vacancies. After the pulsed electric field-induced NH3 modification, the surface potential distribution of the modified perovskite film becomes more uniform, leading to improved charge carrier transport. As a result, the average power conversion efficiency (PCE) of the devices increases from 23.32% to 24.79%. After aging at ambient condition for 1000 hours without encapsulation, the NH3-treated devices subjected to the pulsed electric field retain 84% of their initial PCE, which is significantly higher than the 75% retained by the control counterparts.
  • Li Wanghui, Li Zhendong, Li Shuai, Hu Jinchao
    PDF ( )   Knowledge map   Save
    Aiming at the strong power volatility of photovoltaic power generation and the fact that traditional power prediction methods are difficult to meet the high-precision requirements, a TBiLSTM hybrid network model based on multi-temporal sequence feature fusion is proposed. Firstly,this model normalizes the input multi-dimensional temporal sequence features and introduces learnable positional encoding to retain the sequential information of the time series. Secondly,the preprocessed feature matrix is input into the Transformer encoder,and the multi-head self-attention mechanism is used to model the global dependencies among time steps. After the output of the encoder undergoes residual connection and layer normalization,it is fed into the Bidirectional Long Short-Term Memory Network (BiLSTM),and the BiLSTM extracts the local temporal dynamic characteristics through forward and backward propagation. Finally,the hidden states of the BiLSTM are mapped to the predicted power sequence through the fully connected layer. Two groups of public datasets are used in the experiment,covering multi-dimensional temporal sequence features such as irradiance,temperature,pressure,and humidity. The experimental results show that compared with the BiLSTM,CNN,and CNN-BiLSTM prediction models,the proposed model reduces the mean absolute error by an average of 37.16%,47.63%,and 12.43%,the mean absolute percentage error by an average of 55.59%,68.80%,and 8.79%, the mean squared error by an average of 52.11%,68.47%,and 20.98%,the root mean squared error by an average of 33.75%,45.49%,and 11.13%, and increases the coefficient of determination by an average of 4.03%,4.03%,and 2.13%. This verifies the reliability and superiority of the proposed model.
  • Zhou Yucai, Qin Yuanheng, Xiao Zhenjiang, Xie Qiyue, Fu Qiang, Tan Yanxiang
    PDF ( )   Knowledge map   Save
    To address the volatility and uncertainty of photovoltaic (PV) power generation, this study proposes a short-term PV power forecasting method based on fuzzy C-means (FCM) clustering, hybrid scale feature extraction (HSFE), and multi-head dynamic sparse attention (MDSA) mechanism integrated into a bidirectional gated recurrent unit (BiGRU) framework. First, historical PV data undergo preprocessing and outlier analysis, followed by a correlation analysis of the factors influencing PV output under different weather conditions. Then, dimensionality reduction is performed, and FCM is used to classify the input data based on weather conditions. The clustered data are fed into a BiGRU model enhanced with the HSFE module to enhance its capability in extracting information across different temporal scales. Furthermore, the multi-head dynamic sparse attention mechanism is incorporated to dynamically adjust the model’s focus on temporal features across time steps. Simulation results and comparative experiments demonstrate that the proposed composite model achieves superior accuracy and generalization performance compared to benchmark methods.
  • Liu Jinzi, Li Chentao, Guo Han
    PDF ( )   Knowledge map   Save
    To solve the problem of effective energy flux density calculation for heliostat fields, a calculation method based on the backward projection algorithm is proposed for effective energy flux density on heliostat facets. An irradiance function is used to replace cosine efficiency and truncation efficiency to judge judge whether there is shadow occlusion, calculate the output power of a single heliostat, and accumulate the total power of the heliostat field. By reordering the total power of the heliostat field and integrating the area above the heliostat, the distribution function of the surface energy flow density of the heat absorber can be obtained. With this distribution function, the heliostat contour with maximum power under fixed mirror area or other constraints can be optimized, and the optical efficiency of heliostat fields with various contours and layouts can be quickly assessed. Numerical simulation results indicate that compared with traditional rectangular and polygonal heliostats, the heliostat contours optimized by the proposed algorithm need smaller mirror area for equal power output and feature favorable stability.
  • Yang Yuke, Sun Beibei
    PDF ( )   Knowledge map   Save
    To address the research demand for the vibration characteristics of parabolic trough solar collectors, the theoretical expressions for modal participation factors and cumulative effective mass participation ratios are derived based on the differential equations of motion in structural dynamics. In finite element modal analysis, the modal truncation criterion requiring the cumulative effective mass participation ratio to reach 90% is adopted to determine the number of modes to extract, and computational modal parameters under different pitch angles are obtained. Concurrently, field modal tests are conducted on a parabolic trough solar collector prototype to obtain experimental modal parameters under multiple operating conditions. The results show that extracting the first 15 modes yields a cumulative effective mass participation ratio of 91.20%, which satisfies the engineering requirement for dynamic analysis. The corresponding mode shapes from tests and simulations are highly consistent, with a maximum relative error of 3.86% for natural frequencies, thus effectively validating the applicability of the established finite element model.
  • Liu Hongxia, Gao Jiacheng, Maimaitiaili·MaimaitiYiming, Huang Ling, Zhang Guanfeng, Gong Qing
    PDF ( )   Knowledge map   Save
    Based on observational data of total solar irradiance from the Hotan National Reference Climate Station (1961-2023), this study quantitatively analyzes the temporal variation characteristics and meteorological impacts of solar radiation in Hotan city. The results show that Hotan is endowed with exceptionally abundant and stable solar energy resources, with annual total solar radiation showing a significant increasing trend of 7.03 MJ/m² per decade. Seasonal radiation intensity follows a descending order: spring> autumn>summer>winter. Monthly variation exhibits a unimodal pattern peaking in June (2132 MJ/m²) and reaching minimum values in December (433 MJ/m²). Diurnal variation demonstrates characteristics of midday maxima, with peak radiation predominantly occurring at 13:00 local time. Different weather conditions cause varying degrees of attenuation of total solar radiation. Among them, rainy days, cloudy days and overcast days have the most obvious impact on the attenuation of total solar radiation in Hotan (36.8%-72.4% attenuation). The continuous radiation stability (annual variation coefficient<6.5%) coupled with high intensity (cumulative annual radiation exceeding 6000 MJ/m²) makes Hotan the preferred candidate for large-scale and sustained solar energy development. These findings provide critical baseline data and theoretical support for optimizing photovoltaic system deployment in arid climate zones.
  • Liu Xinping, Mao Yinghao
    PDF ( )   Knowledge map   Save
    A double-layer particle swarm optimization scheduling method based on weather probability model is proposed to address the problems of low accuracy of solar irradiance prediction and large data volatility in cross day scheduling of photovoltaic-solar thermal integrated energy systems, in order to ensure the stability and economy of the system. Establish a probability distribution model for solar irradiance intensity based on the Beta distribution, and design a 72 hour-24 hour double-layer particle swarm optimization architecture based on the probability model. The upper layer responds to weather uncertainty by storing solar thermal energy reasonably, while the lower layer performs economic scheduling based on the probability of weather changes. The case analysis shows that the collaborative mechanism improvement strategy of probability model and double-layer optimization can solve the optimal irradiance intensity point of the system under different weather types. Compared with traditional scheduling strategies, it can achieve the coordinated optimization of energy configuration and scheduling cost of thermal storage systems under various uncertain weather conditions for a long time scale.
  • Yan Renwu, Bao Jinsheng, Li Peiqiang
    PDF ( )   Knowledge map   Save
    In light of the escalating frequency of extreme disasters in recent years, there is an urgent need to enhance the resilience of the power system during disasters. This paper proposes a two-stage resilience enhancement strategy that considers the collaborative recovery of Mobile Energy Storage System , Repair Crew, and Distribution Network Reconfiguration. In the pre-disaster stage, the probability of failure is calculated based on the improved Rankine wind field model, which incorporates the wind strength of the line. The Frank-Copula function is then used to predict the scenarios of regional correlation of wind power, and a two-layer three-stage robust optimization model is established to consider the uncertainty of the wind power. The optimal pre-deployment location of the MESS is then determined. The establishment of a MESS-RC-network reconfiguration multi-source cooperative power supply restoration model is undertaken with the objective of minimizing the weighted value of load reduction power in the mid-disaster phase to improve the power supply reliability. The validity of the proposed strategy is verified by the improved IEEE 33-node and 47-node traffic topology, which demonstrates its effectiveness in enhancing the power system’s resilience.
  • Liu Shuming, Shi Hongda, Cao feifei, Fei huaping
    PDF ( )   Knowledge map   Save
    Based on the background of “Carbon Peak, Carbon Neutral” and the richness of clean energy resources in large ports, a multi-clean energy integrated supply system is proposed for large ports, and a model of multi-energy integrated supply system for large ports that combines wind energy, photovoltaic energy, hydrogen energy, energy storage, and utility power is established. According to the measured data of a port on the typical day in spring, the particle swarm optimization (PSO) algorithm is adopted to optimize the integrated supply model by deploying various energy sources and flexible loads with the goal of reducing the power cost of the port under the two models with or without flexible loads. The results show that the two models achieves the effect of peak shaving, valley filling, cost reduction and efficiency improvement through the optimization of the system. Compared with the power supply from the utility only, the costs of electricity of the two models are reduced by 32.60% and 37.73%, respectively. The percentages of the using clean energy are increased by 55.46% and 58.54% respectively, which verifies the feasibility and practicability of the integrated supply system for large ports.
  • Luan Fuming, Zhang Heng, Chen Haiping
    PDF ( )   Knowledge map   Save
    To address the challenges posed by wind power’s intermittency and random fluctuations to grid security, this paper investigates a wind-gas-storage virtual power plant (VPP). By coupling an electric boiler, thermal storage tank, and lithium bromide heat pump, it constructs a “dual-decoupling architecture for electricity-heat interaction” and proposes a time-of-use electricity pricing-based, two-layer coordinated optimization control model for the VPP’s day-ahead and intraday operations. The upper layer aims to maximize pre-day net revenue by formulating dispatch plans based on wind power and thermal load forecasts. The lower layer targets real-time operational cost minimization by dynamically adjusting unit outputs according to real-time data. Research indicates that under this model, the VPP’s actual output precisely tracks pre-day declared plans, with intraday output deviation ranges (-37.8 MW to 64.0 MW) significantly narrower than wind forecast errors, effectively reducing penalty costs. Integrating energy storage systems enables energy transfer by storing electricity and heat during off-peak periods and releasing energy during peak periods, optimizing gas turbine operation strategies and enhancing economic benefits. Increasing battery storage capacity has a limited impact on net profit growth, while net profit growth slows after thermal storage capacity reaches 500 MW·h. This research provides important insights for promoting renewable energy integration and building low-carbon power systems.
  • Li Yanyan, Xue Xian
    PDF ( )   Knowledge map   Save
    To address the problems that multiple frequency-regulation units cannot effectively coordinate frequency regulation under extreme disasters and that heterogeneous frequency-regulation units are difficult to coordinate, this paper proposes a multi-agent-based distributed consensus cooperative automatic generation control (AGC) method. Firstly, a distributed consensus-based multi-source cooperative AGC framework is established to enable multiple frequency-regulation units to participate collaboratively in secondary frequency regulation. Secondly, according to distributed consensus theory and the dynamic operating characteristics of different frequency-regulation units, a distributed consensus-based area control error (ACE) estimation algorithm is proposed. Then, each frequency-regulation unit participates in frequency regulation through an independently designed PI controller according to the estimated ACE signal of its area. Finally, in the later stage of frequency regulation, the output power of frequency-regulation units with relatively slow response speeds is adjusted to release the frequency-response capability of units with faster response speeds, thereby reserving frequency-regulation capacity for the next regulation cycle. A microgrid simulation model is built in Matlab/Simulink, and the simulation results show that the proposed AGC method can effectively coordinate heterogeneous frequency-regulation units for frequency regulation and exhibits strong disturbance rejection capability under extreme disasters.
  • Yan Xiangwu, Cao Heyang, Tong Sihan, Shao Chen, Jia Jiaoxin, Lin Yixuan
    PDF ( )   Knowledge map   Save
    Addressing the problem of short-term load forecasting difficulty in power systems, this paper proposes an integrated learning load forecasting model that considers the spatio-temporal joint influence of load areas. Firstly, a spatiotemporally joint sampling scheme for load areas is proposed, using recent load data from other load areas to predict the load in the current load area, thereby making more use of highly time-sensitive data. Secondly, base learners are constructed based on machine learning and neural network models such as Extreme Gradient Boosting (XGBoost). Combined with cross-validation, an improved Bayesian algorithm is used to distributedly optimize model hyperparameters, aiming to maximize their respective prediction performance. Thirdly, a meta-learner is built based on deep learning to implement Stacking ensemble learning, enabling it to combine the learning results of each base learner to output the final predicted value. Finally, case study validation is performed using a load dataset from southern China, and comparisons are made with commonly used sampling methods, verifying the feasibility and superiority of the proposed integrated learning model and sampling feature scheme.
  • Huang Liyan, Ai Xin, Wang Zhe
    PDF ( )   Knowledge map   Save
    To solve the cooperative game problem of multi-energy sharing among cross regional integrated energy systems in uncertain source load environments, firstly, considering the multi-energy collaboration characteristics between cross regional integrated energy systems, taking the wide area integrated energy system interconnected by multiple cross regional integrated energy systems as the research object, a multi-energy sharing cooperative operation model for wide area integrated energy systems is constructed. Secondly, in order to solve the cooperative game and fair distribution of benefits between resource endowment integrated energy systems, a Nash negotiation model for wide area integrated energy system electric and thermal sharing based on asymmetric bargaining is proposed on the basis of the established integrated energy system model. Then, in order to protect the data privacy of cooperative entities and reduce the impact of source load uncertainty and improve the reliability of Nash negotiations in wide area integrated energy systems, a two-stage robust Nash optimization method of day-ahead real-time is proposed, and the alternating direction multiplier method and column and constraint generation algorithm are used for solving. Finally, through case analysis, it is verified that the proposed model and method can effectively improve the adaptability of strategies, fairness of benefit distribution, and low-carbon economy of the system in uncertain environments.
  • Zu Wei, Ying Zhangfen, Yang Yi
    PDF ( )   Knowledge map   Save
    In the paper, based on an improved equivalent thermal network and multi-objective parameter identification, a method for estimating the temperature difference of TEG modules is proposed. This method firstly improves the traditional equivalent thermal network to describe the nonlinear influence of environmental thermal convection and heatsink on module heat dissipation. Then, using the minimum estimation errors of the hot side, cold side, and heatsink temperatures as multi-objective functions, the thermal parameters of the module are identified by combining the convex function characteristic analysis and the non-dominated sorting genetic algorithm II. Finally, the temperature difference between the hot and cold sides is quickly estimated based on the identified parameters and the improved equivalent thermal network. The proposed method is experimentally validated under natural convection conditions where the change in heat dissipation power is most pronounced nonlinearly. The results show that this method can extract TEG module thermal parameters that are difficult to calculate theoretically with high precision and accurately estimate the dynamic changes in the temperature difference between the module's hot and cold sides under natural convection conditions.
  • Dai Zhihui, Ning Zhiheng, Liu Meiyuan, Liu Junyi
    PDF ( )   Knowledge map   Save
    The inverter-type distributed generation (IIDG) represented by photovoltaics is connected to the grid by T-connection, which leads to the risk of incorrect operation of the original distance protection device in the distribution network. Based on this, an adaptive distance protection principle for distribution lines suitable for IIDG-T connection is proposed. Firstly, combined with the output characteristics of IIDG fault, the causes of misoperation and rejection of traditional distance protection in IIDG-T connected distribution network are analyzed. Secondly, based on the fault equivalent network, the evolution law of the fault electrical quantity of the distribution line with IIDG-T connection is explored. Finally, a complete adaptive distance protection scheme is constructed for three-phase short-circuit and two-phase short-circuit fault scenarios. The simulation results show that the proposed scheme can adaptively adjust the setting value only by relying on the local measurement information, which can reduce the communication cost of the distribution network. At the same time, the proposed scheme is not disturbed by the IIDG-T connection capacity, output fluctuation, fault location and type, and has good applicability in the IIDG-T connected active distribution network scenario.
  • Dai Wendong, Jin Ping
    PDF ( )   Knowledge map   Save
    To address the issue of wind and solar curtailment caused by the high proportion of renewable energy connected to the power grid in Ningxia, an active distribution network-based "source-load-storage" collaborative interactive optimization scheduling method. This method is developed based on Pelican optimization algorithm (POA) - Grey Wolf optimization algorithm (GWO) - Cross over optimization algorithm (CSO) is proposed. First, based on the thermal storage capacity of the building envelope structure, a building thermal dynamic model with flexible resources such as air conditioning is established. By comprehensively considering the wind and photovoltaic output characteristic curves and the operational constraints of active distribution networks and energy storage stations, a "source-load-storage" collaborative operation model of active distribution networks is constructed. Secondly, a multi-objective interactive optimization scheduling strategy for active distribution networks "source-load-storage" is proposed, which fully utilizes the operational flexibility of loads and energy storage stations, reduces system operating costs, and improves the absorption rate of renewable energy. Then, to improve the accuracy of solving multi-objective optimization problems, the POA-GWO-CSO optimization algorithm is used to solve the model. Finally, based on the actual operational dataset of Minning Town in Ningxia, the impact of different optimization scheduling strategies on the operation of active distribution networks and the consumption of renewable energy is compared and analyzed, thereby verifying the effectiveness of the strategies proposed in this paper.
  • Sun Mingrui, Wen Yunfeng, Liao Bangkun, Wang Jingwen, Fu Guobin, Wang Xuebin
    PDF ( )   Knowledge map   Save
    To address the critical issue of the lack of online assessment methods for nodal inertia in practical power grid dispatching and control, this paper proposes a nodal inertia assessment method in renewable energy power systems based on the vector fitting method. By analyzing the frequency response mechanisms of various inertia resources, a unified assessment framework for nodal inertia is established, covering both synchronous generators and renewable energy units. A transfer function parameter identification model is then developed based on the vector fitting method, and inertia levels are inverted by measuring the dynamic characteristics of nodal active power-frequency transfer function. To overcome the sensitivity of the traditional vector fitting method to initial pole configuration, particle swarm optimization is introduced to optimize the initial pole configuration, using frequency fitting mean square error as the fitness function. Finally, multiple operating condition simulations on an improved IEEE-39 node system demonstrate that the proposed method has significant advantages in assessment accuracy and applicability.
  • Zhang Qi, Liu Yuqing, Yang Hui, Ren Biying, Sun Xiangdong
    PDF ( )   Knowledge map   Save
    To address the issues of flexible capacity expansion, intelligent energy management and customer benefit optimization for residential PV-storage hybrid inverters in parallel operation mode, this paper proposes an energy management strategy based on mathematical programming methods. By targeting household energy storage battery capacity, photovoltaic installed capacity, inverter power rating, as well as electricity consumption data and price information, this method extracts supply and consumption characteristics, establishes a mathematical model for energy management of hybrid inverter systems, and employs mixed-integer linear programming (MILP) to solve the model, thereby providing dynamic planning references for energy management modes. The planning results demonstrate that this method can reduce users’electricity costs while maximizing the utilization of photovoltaic resources, and it is adaptable to scenarios with different battery configurations.
  • Li Xiaofeng, Zhang Fangying, Huang Yudai, Zhang Gaohang
    PDF ( )   Knowledge map   Save
    This paper proposes an optimal scheduling method of integrated energy system considering carbon-green certificate trading and demand response of new energy vehicles. Firstly, the operation framework of the integrated energy system was constructed, the multi-energy complementary optimization operation mechanism of the system was discussed from three aspects of energy supply, energy conversion and storage, and energy demand, and the multi-energy load demand response model of the system was constructed. Then, based on the carbon emissions of fuel vehicles, it was proposed that electric vehicles and hydrogen vehicles participate in the operation of carbon trading market. Secondly, taking the green electricity trading mechanism as a reference, a new energy vehicle green certificate trading mechanism based on electric vehicles and hydrogen vehicles was proposed. Finally, the low-carbon economic optimization operation model of integrated energy system was established with the goal of minimizing the total operating cost. The effectiveness and feasibility of the proposed operation method are verified by the example analysis.
  • Li Meishu, Shi Rongliang, Zhang Lei, Li Junhui, Lai Zhenhui, Bai Xinyuan
    PDF ( )   Knowledge map   Save
    To address the challenging of trade-off between the active power transient response and inertia response characteristics of fractional-order virtual synchronous generators (FOVSGs) during grid-connected operation under abrupt variations of the active power command and grid frequency, a grid-connected power-frequency response optimization strategy based on lead-lag correction (LLC-FOVSG) is proposed. This strategy introduces a lead-lag correction block into the rotor motion equation of the FOVSG to constitute the LLC-FOVSG. By constructing a grid-connected power-frequency small-signal model of the LLC-FOVSG, a systematic tuning method for control parameters is achieved. Subsequently, a 100 kV·A FOVSG simulation model and a hardware testing platform are established for comparative tests. The results demonstrate the superiority of the proposed LLC-FOVSG over the conventional FOVSG in enhancing the power-frequency response performance of the grid-connected system.
  • Tan Fangkun, You Yanfei, Wang Yiyong, Qiao Tingli, Liu Jian
    PDF ( )   Knowledge map   Save
    This paper proposes a new cascaded H-bridge power electronic transformer(CHB-PET) based on two-level unified control. The DC/DC isolation stage adopts a resonant push-pull structure, which has fewer switch tubes than the traditional scheme. In addition, the two-level unified control based on the open-loop modulation of the isolation stage reduces the system control complexity and avoids the cascading stability problem in independent control. This paper describes and analyzes the working principle, equivalent model, control design, and system evaluation of the proposed scheme. The evaluation results show that the proposed CHB-PET has improved in terms of cost, efficiency, and stability compared to the traditional scheme, but decreased in terms of intermediate bus voltage balance and device pre-commissioning. Simulation and experimental results verify the effectiveness of the proposed CHB-PET scheme.
  • Du Long, Li Fengting, Su Changsheng, Li Zhongzheng, Liao Mengke, Peng Shasha
    PDF ( )   Knowledge map   Save
    A short-term power load forecasting method based on soft dynamic time warping-improved partitioning around medoids (SDTW-IPAM) and Informer is proposed to address the problem of power load volatility and nonlinearity enhancement. Firstly, the soft-DTW distance metric is introduced to accurately portray the dynamic time-series characteristics of the load curve and effectively identify the local deformation of the load curve; and the PAM clustering algorithm is improved by combining the Gap statistic and the K-means++ initialization strategy, which classifies the original loads into bimodal loads, peak loads and smooth loads, so that the model training is more targeted. Secondly, the maximum information coefficient (MIC) is applied to the typical loads of each category for feature selection, which identifies the key influencing factors of the loads and achieves differentiated feature extraction. Meanwhile, in order to improve the prediction performance of the model, the Informer model is introduced to construct exclusive prediction models respectively. Finally, the actual load data of Urumqi, Xinjiang is used as an example for validation, and the results show that the proposed combined forecasting model can effectively improve the accuracy of short-term load forecasting and has strong practical value.
  • Wu Chenxi, Li Hao, Xu Yuxin, Yang Lang
    PDF ( )   Knowledge map   Save
    Firstly, modeling renewable energy generation and energy storage devices based on the supply/storage characteristics of the park, and establishing various equipment operation constraint models. Secondly, taking the lowest cost of the integrated energy system in the park as the upper level planning objective and the operating cost as the lower level scheduling objective, genetic algorithm is used to solve the optimal source/storage capacity planning configuration. Considering the optimization problem of operation in planning, the adoption of flexible load control serves to reduce the disparity between peak and off-peak loads and alleviate the pressure of peak energy consumption. Finally, the superiority of system planning under energy supply reliability is verified through practical examples in urban parks. The proposed method can meet the load demand of the system while ensuring economic efficiency.
  • Mao Rui, Su Xiaoling, Zhao Zhengkui, Chen Laijun, Pei Wei
    PDF ( )   Knowledge map   Save
    Influenced by the difference of inertia, damping and other parameters, the grid-forming voltage-source converters (GFM-VSC) operating in parallel with multiple machines is very susceptible to power-frequency oscillations under the change of operating environment. In this paper, firstly, based on the small-signal model, the root trajectory and Bode diagram are used to determine the main causative factors and mechanisms triggering the power-frequency oscillations of the grid-type converter multi-machine paralleling system. Secondly, according to the state feedback theory, a decentralized transient damping lifting control strategy is proposed to improve the damping of a single GFM-VSC by angular frequency compensation and electromagnetic power compensation. On this basis, the additional mutual damping torque is introduced to reduce the angular frequency difference of the multi-GFMVSC and improve the system coordination. Finally, the correctness of the control strategy is proved by using the Lyapunov functions, and the feasibility and effectiveness of the proposed control is verified by simulation and experimental results.
  • Zhao Yongxiu, Jia Haoyang, Wang Chongjie, Lei Ming, Liu Zeiwei
    PDF ( )   Knowledge map   Save
    Aiming at the problems such as narrow input voltage gain range and large voltage stress existing in traditional full-bridge or half-bridge LLC converters, a wide input voltage series half-bridge LLC resonant converter is proposed. By analyzing the converter topology, the front-stage series half-bridge structure can realize the switching tube voltage stress halving, and the dual resonant cavity common resonant inductor can realize the two-phase automatic current equalization, which verifies its automatic current equalization characteristics. Under the premise of ensuring the efficiency, by analyzing the working principle of high and low gain modes, the frequency doubling technique is introduced to widen the input voltage range, and a hybrid PSM-PWM-PFM control method is proposed to realize the stable switching between modes. In addition, by analyzing the principle of input capacitor voltage imbalance, a PSM-PWM hybrid equalization control method is proposed to achieve input capacitor voltage balance. Finally, a prototype with an input voltage of 100-400 V and a full load of 600 W is built to verify the correctness of the proposed theoretical analysis and the feasibility of the proposed control strategy.
  • Zhao Feng, Zeng Bing, Tan Beisi, Chen Xiao, Li Zhi, Zhang Wenchao
    PDF ( )   Knowledge map   Save
    In order to improve the power angle and voltage stability of the sending end power grid, this paper first establishes the model of the external sending end system of new energy power generation, and optimizes the new energy output based on the stability of the sending end power grid. Secondly, the system power angle and voltage change under disturbance are analyzed, and the virtual power angle model of new energy power generation is established. Then, a power angle stability control model based on energy fluctuation is established to analyze the influence of energy fluctuation on power angle stability. Finally, aiming at the minimum power angle deviation and the maximum transient stability margin of the sending end power grid, the multi-objective optimization algorithm based on neural network is used to calculate, and the effectiveness of the proposed method is verified by simulation.
  • Zhang Tao, Zhang Yafei, Zhang Li, Han Qinglin, Li Yunfei, Bai Wenlong
    PDF ( )   Knowledge map   Save
    To address the problem that conventional LLC resonant converters have to drastically extend the operating frequency range to realize wide voltage gain, which further leads to a prominent reduction in the overall system efficiency, a high-gain-ratio dual LLC resonant converter (HGRD-LLC) is proposed in this paper.The proposed converter adopts dual resonant tanks with modulation of distinct switching drive signals. By operating the half-bridge and full-bridge LLC resonant converters independently or in combination, five operating modes with different voltage gains are obtained. While maintaining the inherent merits of LLC resonant converters across all modes, the topology achieves a wide output voltage gain range and substantially improves the conversion efficiency.The voltage gain of the presented converter is derived based on the fundamental harmonic approximation (FHA), and the zero-voltage switching(ZVS)constraint conditions of the converter are quantified. Finally, an experimental prototype with an output voltage range of 60-480 V and a maximum power rating of 960 W is built to verify the feasibility of the proposed topology.
  • Jiang Qi, Pan Wenxuan, Lin Xingyu, Zhang Yifan, Tang Junjie, Zhou Niancheng
    PDF ( )   Knowledge map   Save
    For renewable energy bases in gobi and desert areas exporting power via high-voltage direct current (HVDC) transmission links, addressing the challenge of low computational efficiency when evaluating their renewable energy integration rates and transmission corridor utilization rates through time-series production simulation under probabilistic scenarios, this study proposes a fast probabilistic analysis method based on a dimension adaptive sparse grid interpolation (DASGI) surrogate model for time-series production simulation. First, Monte Carlo sampling is integrated with time-series production simulation to perform probabilistic analysis under dual uncertainty factors. Then, the DASGI surrogate model is employed to approximate the complex original model within time-series production simulations, enabling fast probabilistic analysis and risk assessment. Experimental results demonstrate that the DASGI model achieves high consistency with the original simulation while significantly reducing the computation time. Moreover, the DASGI model, when applied with a larger sample size, effectively identifies potential exceeding limit risk.
  • Tuo Xianfeng, Chen Qian, Xu Yang, Wang Sijin
    PDF ( )   Knowledge map   Save
    To address the problems of unclear carbon responsibility allocation and insufficient carbon reduction motivation among multiple parks under the carbon trading and green certificate mechanisms, this paper proposes a multi-park comprehensive energy optimization method based on nodal carbon potential and dual game. Firstly, the carbon potential model whose node is the energy sub network of a park is established, then the carbon responsibility allocation method based on the model above is proposed. Secondly, a Stackelberg game model between integrated energy suppliers and load aggregators in the park is established, and a Nash game model is used to address the cooperative game between multiple parks, thereby forming a dual game mechanism. Thirdly, the model is transformed by combining interval possibility transformation and KKT conditions, and an accelerated ADMM algorithm is proposed for solving. Finally, the correctness and effectiveness of the proposed model and improved algorithm are verified through comparison of numerical examples, that carbon responsibilities can be located effectively, with carbon emissions of multiple parks reduced and benefits overall improved.
  • Zhao Wenfei, Yu Guochen, Lan Tianxiao, Li Chunyu, Fu Jiajia, Qi Zhiyuan
    PDF ( )   Knowledge map   Save
    In this paper, a microgrid collaborative optimal scheduling model with electric heavy truck battery swap station is proposed, and a "microgrid-battery swap station" optimization scheduling model with the maximum benefit of microgrid is constructed, and the optimal output of each equipment is calculated. A collaborative optimization model of "heavy truck-battery swap station" was established, and the battery swap station affected the arrival of electric heavy trucks by adjusting the service fee, so as to optimize the load of the battery swap station. The CPLEX solver and antelope optimization algorithm were used to solve the model to verify the effectiveness of the model.
  • Zhao Ke, Xiao Chuanliang, Peng Ke, Chen Jiajia, Feng Liang, Zhou Qiang
    PDF ( )   Knowledge map   Save
    In order to solve the problem of location and capacity determination and reliability index calculation of distributed resources in distribution network with high proportion of distributed generators, a robust joint planning method of distributed resources in distribution network based on cluster division is proposed. Firstly, a comprehensive cluster division index of distribution network was proposed, which included modularity index, power balance index and inter-group branch power fluctuation index. Secondly, on the basis of cluster division, a two-layer joint programming model is proposed, and the upper layer considers the uncertainty of the source and load in the cluster, establishes a source-storage robust addressing and capacity model, and determines the range of the source-load uncertainty set through the uncertainty adjustment parameters, so as to obtain the optimal access location and capacity of distributed power generation and energy storage. The lower layer considers the calculation of reliability indicators in the cluster to ensure the reliability of operation and reduce the conservatism of optimization results. Finally, the simulation analysis of the actual photovoltaic distribution network in China is carried out to verify the effectiveness of the proposed method.
  • Chen Wei, Nie Dacheng, Wei Zhanhong, Lin Jie
    PDF ( )   Knowledge map   Save
    Aiming at the problems of excessive carbon emissions in high energy-consuming industrial parks and insufficient consumption of new energy, this paper proposes an optimal scheduling model that incorporates concentrated solar power plants, wind power, photovoltaic power, and self-supplied power plants in high energy-consuming industrial parks. This model integrates short-term generation rights trading with a ladder-type carbon emission-green certificate hybrid market mechanism. Firstly, based on the energy time-shifting characteristics of the thermal storage system in concentrated solar power plants and the electric-thermal coupling mechanism, a power coordination model for a multi-energy complementary system is constructed to smooth the fluctuations in the output of wind and solar power and enhance the consumption capacity. Then, a strategy for combined short-term generation rights trading is designed. Through the conversion mechanism among generation rights green certificates, carbon quotas, and green certificates, the output of new energy is dynamically matched with the regulation requirements of self-supplied power plants. Finally, taking a certain high energy-consuming industrial park in Jiuquan, Gansu Province as an example for simulation, the results show that this method can not only effectively reduce the carbon emissions of high energy-consuming industrial parks but also improve the consumption capacity of renewable energy. In addition, after the introduction of concentrated solar power plants, the total cost of the park is further reduced, achieving a dual optimization of environmental and economic benefits.
  • Xiong Xinhua, Li Chang, Yang Yaqian, Yuan Jun, Zhao Chanjuan
    PDF ( )   Knowledge map   Save
    To address the insufficient inertia and damping of power systems under high-penetration renewable energy integration, the grid-forming virtual synchronous generator (GFM-VSG) system emulates the operating mechanisms and dynamic characteristics of traditional synchronous generators to provide inertia and damping support to the grid. To address this issue, this paper aims to develop a model and assessment method for oscillation transfer effects, revealing the underlying mechanisms of oscillation transmission and analyzing the root causes of SSO-related instability in depth. The study finds that sub-synchronous oscillations in GFM-VSG systems are not solely caused by insufficient stability margins but may also result from oscillation transfer effects between different electrical quantities. Based on the proposed oscillation transfer effect assessment framework and analytical method, the oscillation transfer effects in GFM-VSG systems can be quantitatively evaluated. Finally, experiments verify the effectiveness and feasibility of the proposed modeling method and assessment framework.
  • Ma Zhaoxing, Liu Chengshuang, Xu Peng, Chen Hao, Wang Ruihua
    PDF ( )   Knowledge map   Save
    This article proposes a new method for carbon emission accounting in green certificate trading that integrates geographic spatial information. Firstly, establish a green certificate carbon emission reduction correlation model, systematically classify green certificate trading types, and formulate corresponding accounting criteria; Secondly, construct a differentiated accounting framework based on transaction characteristics to achieve spatial matching between green certificate transactions and regional power grids; Then, Kalman filtering data processing technology and inversion technology are used to optimize the accuracy of carbon emission monitoring data in thermal power plants; Finally, the rationality and effectiveness of the proposed research method are verified through calculation and analysis using the IEEE 30 node system and a geographical region in China.
  • Ni Daojun, Xiao Jiandong, Xiao Yaoyao, Qi Xin, Zhang Puyang
    PDF ( )   Knowledge map   Save
    The mono-column composite bucket foundation is an innovative foundation structure developed in China and has been applied in several offshore wind power projects. However, the assessment of its bearing performance under scour conditions remains insufficiently understood. In this study, finite element analysis was first conducted to evaluate the bearing capacity of the mono-column composite bucket foundation under different loading directions and to examine the influence of scour on the natural frequency and stiffness of the foundation, thereby identifying the most unfavorable scour condition. The bearing behavior of the foundation under different scour conditions was then investigated under Tianjin clay-covered soil conditions. The research results indicate that variations in the loading direction relative to the scoured zone and in scour pattern alter the surrounding soil morphology and consequently affect the ultimate bearing capacity, bending moment, and inclination response of the structure to different degrees. As the scour depth increases from 2 m to 10 m, the lateral stiffness of the foundation decreases by about 15%, while its natural frequency decreases by 7%-8%. Scour extending into deeper soil layers reduces the structural bearing capacity, although the reduction is limited. Complete scour causes a greater decrease in bearing capacity than one-sided scour. Under cyclic loading, the adverse effect of scour on the structural response becomes more pronounced.
  • Huan Caiyun, Jiang Zhenqiang, Qiao Hou, Chen Lulu
    PDF ( )   Knowledge map   Save
    Taking an offshore wind farm in Dafeng, Jiangsu Province as an example, based on the measured underwater terrain data of representative turbine positions, this study analyzes the local erosion characteristics of the pile foundation and the evolution process of the erosion pit, and explores the mechanism of the erosion pit evolution process. The results show that: 1) There is a funnel-shaped scour hole developed on the seabed near the pile foundation, and the planar shape of the scour hole is elliptical. The long axis of the ellipse follows the mainstream direction of the rising and falling currents. The length of the scour hole is linearly correlated with the maximum scour depth of the scour hole. The maximum scour depth of the scour hole occurs on the side of the pile foundation facing the falling current, with a maximum depth of 7-8 meters for the 25# machine position and 5-6 meters for the 55# machine position. 2) During the period from December 2021 to September 2022, the scouring pit underwent a process of first scouring and then siltation, and overall scouring and siltation adjustment. The scouring is mainly distributed on the periphery of the scouring pit, and the siltation is mainly distributed near the pile foundation inside the scouring pit. In September 2022, the impact of Typhoon Muifa caused a certain degree of siltation in the scouring pit. 3) Given the large size and depth of the scour hole, it is recommended to expand underwater terrain monitoring to all machine positions in the site area and take timely anti scour measures to prevent further development of the scour hole.
  • Ma Gaosheng, Zheng Quan, Li Deshun, Kong Lingduo, Luo Fengyang, Xing Jialu
    PDF ( )   Knowledge map   Save
    To investigate the impact of wind turbine wakes on near-surface wind erosion, sand initiation, and dust deposition, OpenFOAM, an open-source software package, was employed to simulate the operation of the wind turbine using the Actuator Line Method (ALM). Large Eddy Simulation (LES) were utilized to reconstruct the flow field, and the Multi-phase Particle-in-cell (MP-PIC) model was applied to solve the interaction between dust particles and the flow. The study examined the influence of wind turbine operation on the surface shear stress under incoming flow with mixed particle sizes, following the logarithmic profile of the atmospheric boundary layer. The effects were analyzed for different wind turbine height-to-diameter ratios (H/D), and the erosion characteristics of the surface were determined based on the critical wind speed formula for sand initiation. The results indicate that the expansion and meandering of the wind turbine wake led to an increase in surface shear stress, with the instantaneous surface shear stress increasing by approximately 80% compared to the case without a wind turbine. The impact of the wind turbine wake on surface shear stress followed a trapezoidal distribution, where the influence range decreases and the intensity weakenes as the height-to-diameter ratio (H/D) increases. The region of wind erosion and sand initiation induced by the wind turbine wake is concentrated on the surface within 2D downstream of the turbine. The onset of wind erosion is delayed as H/D increases, with the highest frequency of wind erosion occurring on the surface between 5D and 10D downstream of the wind turbine. The location and frequency of wind erosion varies slightly for different particle sizes. Dust particle deposition on the surface is related to the distribution of surface shear stress. In the far wake zone (beyond 5D), the deposition is lower where shear stress is higher.
  • Chen Yifeng, Hu Shengqing, Kou Yanni, Chen Lin, Peng Xiaoqiang, Zhang Yangming
    PDF ( )   Knowledge map   Save
    The vibration control issue of an offshore floating wind turbine is considered, an efficient and precise vibration control method is proposed based on the fixed-time approach, where the tuned mass damper (TMD) is installed in the nacelle of the offshore floating wind turbine. A coupled dynamic model of the offshore floating wind turbine is established according to the Lagrange equations. To address the adverse effects of wind and wave disturbances, a fixed-time nonlinear disturbance observer is constructed to accurately estimate and compensate the wind and wave disturbances separately. Based on this, the intermediate control inputs are introduced to solve the underactuated problem, and a fixed-time active vibration controller is designed for each subsystem of the offshore floating wind turbine to achieve the efficient vibration suppression. The fixed-time stability of the closed-loop system is proven by using Lyapunov methods. Simulation results are provided to verify the feasibility and effectiveness of the designed disturbance observer and vibration reduction controller.
  • Li Gang, Meng Xiang, Yang Rui, Duan Changjiang, Yan Wenqian, Yang Yanjun
    PDF ( )   Knowledge map   Save
    To address the problem that threshold setting in fault early warning of wind turbine gearbox bearings relies heavily on empirical experience and lacks adaptability during long-term operation, an adaptive threshold algorithm based on Exponentially Weighted Moving Average and Bilateral Drifting Stream Peaks-Over-Threshold (EWMA-Bi-DSPOT) is proposed. In the proposed method, the bearing temperature time series collected from the SCADA system is first smoothed using an Exponentially Weighted Moving Average (EWMA) to suppress high-frequency noise and short-term fluctuations, thereby improving the stability of subsequent extreme value modeling. During the initialization stage, a high-level quantile is selected as the initial threshold, and the exceedances above this threshold are modeled using a Generalized Pareto Distribution (GPD). The initial alarm threshold is then determined through maximum likelihood estimation of the GPD parameters. In the online stage, the algorithm continuously incorporates marginal extreme values that do not trigger alarms to update the GPD parameters, enabling dynamic adjustment of the alarm threshold to track gradual changes in system operating conditions. This mechanism allows the threshold to evolve with system state drift while preventing abnormal data from contaminating the model during alarm periods. Experimental results based on real wind turbine SCADA data demonstrate that the EWMA-Bi-DSPOT algorithm can achieve adaptive threshold updating for bearing state detection. Compared with traditional fixed-threshold methods, the proposed approach improves the timeliness and reliability of fault early warning while maintaining low false alarm and missed detection rates.
  • Huang Jingbo, Long Kai, Cheng Zhengkun, Zhang Jinhua, Zhang Hui
    PDF ( )   Knowledge map   Save
    To investigate the influence of surface topography on fatigue strength, a harmonic superposition method was proposed for reconstructing surface topography, the analytical expressions of stress concentration coefficient and fatigue notch coefficient were derived, and the empirical formula terms were revised in accordance with DNVGL certification. Based on the DNVGL specification and the proposed method, the cumulative fatigue damage distribution of a wind turbine mainshaft was calculated. The results indicate that within certain conditions, the results of the two approaches are congruent. Under the identical Rz, the fatigue damage value decreases as the surface topography wavelength increases, hence proving the imperative for quantitative analysis of fatigue strength based on measured surface topography.
  • Li Da, Fu Dianfu, Zhang Hui, Sun Guodong, Yang Fengwei, Fu Dengfeng
    PDF ( )   Knowledge map   Save
    Regarding the deep‐water pile anchor for the floating wind turbine, its bearing performacne and failure mechanisms in a typical single‐layer soil are investigated by finite element analysis method.Based on a site-specified geotechnical conditions of a offshore clean energy project, the failure envelope method is then systematically applied to analyze the bearing performance of pile anchor in the multi-layered soil under the combined V-H (vertical-horizontal), V-M (vertical-moment), and H-M (horizontal-moment) loading, resepectively. Then an approach of estimating capacities of pile anchors is developed underlying the failure envelope theory. From this study, V-H load space envelopes are applicable for assessing bearing performance if the pull-out and lateral sliding modes are dominated at failure. Furthermore, the special attention must be paid to moment load effects induced by mooring point eccentricity. Increasing positive moment loads (defined in the study) are found to significantly reduce the pull-out capacity of pile anchors and vice versa.
  • Chang Ning, Dai Liping, Wu Sihang, Li Shixuan
    PDF ( )   Knowledge map   Save
    In order to explore the mechanism of structural coupling on vibration characters of wind turbine blades, a free vibration equation of NREL-5 MW wind turbine blade is derived based on Euler-Bernoulli beam theory, and the effects of shear effect, bend-twist coupling, flap-lag coupling and axial-flexural coupling on the natural modes of the blades are analyzed. The results show that the shear effect decreases the flapwise and edgewise natural frequency, and the second flapwise frequency and the second edgewise frequency decrease by 4.7% and 1% separately. Affected by bend-twist coupling, the bending frequency decreases and the torsional frequency increases, and the effect is more notable for high order natural mode. The effect of the flap-lag coupling on edgewise vibration frequency is greater than that on flapwise, and the effect of the axial-flexural coupling is the least for edgewise and flapwise natural frequency. In terms of vibration modes, both bend-twist coupling and axial-flexural have little influence on the low order vibration modes, and the flap-lag coupling is the main reason for the obvious coupling of the bending vibration modes.
  • Luo Chunkun, Chen Chao, Chen Bei, Wu Faming, Hua Xugang, Chen Zhengqing
    PDF ( )   Knowledge map   Save
    Deep-sea wind energy development represents a strategic high ground in renewable energy and an inevitable solution to overcoming near-shore resource constraints. However, harsh marine environments lead to significantly increasing difficulty and costs in wind turbine operation and maintenance (O&M). Recent advancements in digital technologies such as artificial intelligence, big data, and digital twins have created new opportunities for intelligent and automated O&M of offshore wind turbines. This paper first examines current development trends in offshore wind turbines: large capacity and commercialization, deep-sea and floating, intelligence and automation. Subsequently, it systematically reviews data acquisition methodologies and equipment for offshore wind turbines detection and monitoring, along with advanced data analysis techniques. The state-of-the-art applications of digital technologies in maintaining critical components of offshore wind turbines are comprehensively summarized. Finally, future research priorities for intelligent O&M of floating offshore wind turbines are prospected.
  • Huang Jiajia, Huang Jianwu, Dai Wei, Wang Lilin, Wang Lizhong, Guo Zhen
    PDF ( )   Knowledge map   Save
    For the four-pile jacket foundation of offshore wind turbines, a Python-based parametric modeling program for SACS was developed, relying on data from a practical offshore wind power project. By integrating a genetic algorithm optimization strategy with the program, an intelligent optimization model for the piles in a jacket foundation is developed. Comparative analyses were conducted with the preliminary design and other similar offshore wind power projects to evaluate the optimization performance. The results indicate that: (1) the genetic algorithm-based optimization model exhibits a rapid convergence rate, achieving 93.46% of the final optimal scheme within the first 20 generations; (2) compared with the preliminary design, the optimized scheme reduces the pile foundation mass by 22.35% (approximately 236.40 t), saving over one million RMB per jacket foundation. Compared with other similar projects, the average mass reduction reaches 18.18%; (3) the optimization scheme improves material utilization efficiency by shortening the pile length, reducing the wall thickness, and increasing the pile diameter, thereby reducing mass without compromising bearing capacity and effectively controlling deformation amplitude, which highlights the effectiveness of the proposed optimization strategy in balancing structural safety and economic efficiency. These results demonstrate that the genetic algorithm effectively balances global exploration and local convergence in multi-constraint structural optimization problems, providing a feasible and efficient technical pathway for intelligent optimization design of complex offshore structures.
  • Ou Yangzhan, Huang Yafei, Wang Jiake, Tan Tian, Yang Xin, Yang Zhongyi
    PDF ( )   Knowledge map   Save
    Taking a 300 kW wind turbine at Hunan Xuefeng Mountain Energy Equipment Safety National Observation and Research Station as the research object, this study establishes a three-dimensional rotating icing model for full-scale wind turbine blades based on a rotating reference frame and Eulerian gas-liquid two phase flow model. The model reveals the similarities and differences between rime and glaze ice accretion mechanisms. Through numerical simulations, the differences in ice morphology and mass accumulation between these two ice types are systematically compared, with particular emphasis on temperature effects. The results demonstrate that: 1) Temperature shows negligible influence on rime ice accretion but significantly affects the accretion area, morphology, and mass of glaze ice; 2) Rime ice forms streamlined shapes while glaze ice develops horn-shaped features, with the latter's accretion area decreasing but horn characteristics becoming more pronounced at lower temperatures; 3) The maximum ice thickness of rime ice increases monotonically along the blade span, whereas glaze ice exhibits distinct non-monotonic characteristics-under near-freezing conditions (e.g., -1 ℃), unusual cases occur where mid-span ice thickness (at 0.60R) exceeds tip thickness (at 0.90R); 4) Under identical icing durations, rime ice accumulates greater mass than glaze ice, with the latter showing a decelerating growth trend as temperature decreases.
  • Ye Juan, Nie Feng, Liu Fei, Chen Yanbin
    PDF ( )   Knowledge map   Save
    Referring to IEC 61400-12-3, this study explores the factors affecting wind speed calibration relationships based on practical cases. The impacts of sensitive factors—including wind speed, wind shear, inflow angle, and turbulence—on wind speed calibration results are investigated respectively. Through calibration and quality assessment, it is found that the inflow angle exerts a greater influence on wind speed calibration than wind shear in the cases studied. The correlation between sensitive factors and the wind speed ratio affects calibration quality; when data bins with low correlation are excluded, the calibration quality improves to a certain extent. At the lower blade tip height, the airflow is more significantly affected by surface topography than at the hub height, resulting in poorer wind speed calibration quality at the lower blade tip that fails to meet the requirements of IEC 61400-12-3.
  • Hu Qinyi, Deng Aidong, Zhou Zhongzhi, Xiao Kaiwen, Shen Yang, Wu Yifan
    PDF ( )   Knowledge map   Save
    To address the challenges of data distribution shift and unknown fault identification in wind turbine rolling bearings under varying operating conditions, an open-set fault diagnosis method based on a multi-classifier open adversarial network (MCOAN) is proposed. Specifically, a K-class and a (K+1)-class classifier are jointly employed within an adversarial domain adaptation framework to evaluate the similarity between target and source domain samples. Based on these similarity measures, a dynamic weighting mechanism is constructed to achieve adaptive sample weighting during open-set adversarial training. This mechanism also facilitates the dynamic determination of decision thresholds for known and unknown classes, thereby promoting cross-domain alignment of shared features while enhancing the recognition of unknown samples. In addition, a non-adversarial classifier is introduced to improve the reliability of dynamic weight computation. Experimental results on two datasets demonstrate that the proposed method achieves accurate alignment of shared features and robust identification of unknown faults, showcasing superior diagnostic performance and robustness.
  • Sun Chunhu, Zhang Weiliang, Fang Yuanjie
    PDF ( )   Knowledge map   Save
    In order to improve the convergence time and anti-disturbance performance of the permanent magnet synchronous motor adaptive super-twisting control, an improved adaptive super-twisting controller based on a fixed-time disturbance observer is proposed. By introducing power term in the adaptive super-twisting controller, the convergence speed of the sliding mode controller far away from the origin is accelerated, and the discontinuous symbol function is replaced with a continuous h(s) function, further reducing the vibration. Taking into account the shortcomings of the long convergence time of the traditional disturbance observer and the limited time of the disturbance observer is restricted by the initial state, a fixed-time disturbance observer is designed to make the disturbance converge in a fixed time, and the disturbance estimate value is sent to the sliding mode controller for feed-forward compensation, thereby improving the controller's immunity performance. Finally, the accuracy of the proposed control strategy is verified through simulation comparison between different disturbance observers and sliding mode controllers.
  • Li Jialin, Liu Yuxin, Cao Xuan, Bai Houyi, Chen Renxiang
    PDF ( )   Knowledge map   Save
    Significant progress has been made in the fault diagnosis of wind turbine planetary gearboxes based on deep learning. To address the difficulty to obtain labelled data for training classification models in the task of identifying abnormal states of planetary gearboxes, this paper proposes an unsupervised automatic detection method, in which the Log Mel-band Energies features of the original vibration signals are firstly extracted and input as training data into an unsupervised abnormal state recognition model based on U-net autoencoder as the core for training. Furthermore, based on the reconstruction error between the model inputs and the outputs, a judgment threshold for the health state of the gearbox is set to complete the abnormal state identification task. In this paper, both factory test data of gearboxes and actual operation data of wind turbines from a wind farm in Yangtouya, Shanxi Province are used to validate the reliability of the proposed model. For factory gearboxes, a signal processing method based on spectral amplitude modulation is simultaneously adopted for dual verification. The proposed method achieved an identification accuracy of 93.34% on the factory dataset and the wind farm dataset. This proves that the proposed unsupervised method can automatically and correctly separate abnormal state wind turbine gearboxes.
  • Liu Xiaoyan, Zhen Zhao, Wang Fei, Huang Yuehui, Chang Xiqiang, Mi Zengqiang
    PDF ( )   Knowledge map   Save
    Addressing the limitations of existing wind power forecasting methods, which arise from insufficient extraction of wind power fluctuation information and inadequate analysis of evolutionary patterns, this paper proposes an ultra-short-term wind power forecasting method based on fluctuation continuation scenario identification. First, the coupling mechanism of wind power fluctuations under multiple turbulent processes is investigated, and historical power data are dynamically decoupled into combined nonlinear and linear fluctuation components. The concept of fluctuation extensibility is then introduced to quantify the future persistence scale of wind power fluctuations, which is derived from nonlinear and linear decoupling parameters, based on which fluctuation-extensibility scenarios are defined. Furthermore, a sparse neural network (SNN) tailored for high-dimensional sparse features is developed to identify fluctuation-continuation scenarios of historical wind power data and perform scenario-based ultra-short-term power forecasting. Finally, experiments are conducted on measured wind speed and power data from three wind farms. The results show that, compared with the benchmark models, the proposed method reduces the root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) by at least 1.46%, 2.44%, and 14.67%, respectively, which verifies its superior predictive accuracy and stability.
  • Zeng Qingtao, Tang Guihua, Zhang Xuan, Cheng Jijie, Ma Ping
    PDF ( )   Knowledge map   Save
    In response to the problems that it is difficult to collect a large amount of high-quality fault data during the operation of the planetary gearbox of wind turbines and that the diagnostic accuracy of intelligent diagnostic models is low under the scarcity of fault samples, a fault diagnosis method for the planetary gearbox of wind turbines driven by a combination of numerical and physical models is proposed. First, a high-fidelity dynamic model of the planetary gearbox of wind turbines is constructed based on the lumped parameter method to generate pseudo-fault data. Second, a domain-shared residual network feature extractor incorporating a convolutional block attention mechanism is designed to extract the key physical features of the pseudo-data and the measured data. The local maximum mean discrepancy is introduced to align the feature distributions of the pseudo-fault data and the real fault data at the fault category level. By adopting the Kolmogorov-Arnold network module, the network’s learning ability for complex data relationships is enhanced to achieve the classification and identification of different types of faults. Finally, the proposed method is verified on the fault diagnosis test bench of the planetary gearbox of wind turbines. The experimental results show that compared with other classic methods, the proposed method has a good diagnostic effect under the condition of scarce fault samples.
  • Zheng Wanlang, Tan Jike, Li Yan’e, Zhang Yunhui, Luo Wei, Guo Songling
    PDF ( )   Knowledge map   Save
    To investigate the compression-bending capacity of these joints in concrete wind turbine towers, a 1:4 scale specimen was conducted under combined compression and bending. Additionally, A finite element (FE) model was firstly developed and validated against experimental result regarding to the compression-bending capacity. Results indicate that the FE simulations are close to the experimental value, with differences less than 5%, which verifies the accuracy of the FE model. A systematic analysis of the stress mechanisms affecting the horizontal joints in concrete wind turbine tower was undertaken. Based on the experimental results, theoretical analysis of the stress distribution, and FE parametric study, a calculation method for the compression-bending capacity of the horizontal joints in concrete wind turbine towers was proposed. The predicted values of compression-bending capacity of the horizontal joints from this method exhibits an error of less than 10% compared to both experimental and numerical results, further confirms that the proposed design method for the compression-bending capacity of the horizontal joints in concrete wind turbine concrete towers is accurate.
  • Wang Yan, Wang Zijian, Zhong Xinqi, Liang Shiyu, Zhao Hongshan
    PDF ( )   Knowledge map   Save
    To further enhance the accuracy of fault diagnosis for wind turbine gearboxes, an intelligent diagnostic model based on the improved convolutional neural network (CNN) and extreme gradient boosting (XGBoost) fusion under the Gramian angular difference field (GADF) transformation is proposed. Firstly, the one-dimensional vibration signal data of the gearbox under complex environments are transformed into two-dimensional images through the GADF transformation, which retains the intrinsic structure and time-frequency characteristics of the signals. Secondly, an improved CNN method for multi-dimensional feature extraction of gearbox vibration images is proposed, where dual attention modules are introduced in the convolutional layers of the traditional CNN to enhance the model’s perceptual capabilities and increase the extraction of global information. The improvedβc-ACONC activation function which replaces the ReLU activation function is employed to selectively activate neurons, thereby enhancing the network's overall feature expression capabilities. Then, the integrated features are input into the XGBoost network optimized by ISSA hyperparameters, constructing a wind turbine gearbox fault diagnostic model based on the improved CNN-XGBoost fusion under the GADF. Finally, the performance of the model is verified using a laboratory wind turbine gearbox dataset, and the experimental results demonstrate that the model has a diagnostic accuracy of over 99%, exhibiting excellent fault recognition capabilities.
  • Liu Xianqing, Yang Bo, Zhang Puyang, Zhang Yu, Luo Sheng, Gu Yao
    PDF ( )   Knowledge map   Save
    Focusing on the motion response of the quadrant-bucket foundation of taut-moored wind turbines under wave loads, this paper conducts regular wave-structure interaction experiments using a small-scale physical model to systematically analyze the influence laws of water depth, draft, and anchorage distance on the motion response of the quadrant-bucket foundation. The results show that: with the increase of water depth, the heave motion response of the structure is suppressed; with the increase of draft, the surge and pitch motion responses of the structure increase, while the heave motion response decreases; with the increase of anchorage distance, the heave and pitch motion responses of the structure increase, while the surge motion decreases during the slow-drift response phase.
  • Yue Qian, Ren Guorui, Wang Wei
    PDF ( )   Knowledge map   Save
    Based on the complementary characteristics of wind and solar energy resources in time and space distribution, this paper proposes a joint forecasting strategy of wind and solar power considering complementarity. Based on the bidirectional long short-term memory neural network, a basic forecasting model is established, and a sorting comparison optimization algorithm is further proposed to optimize the parameters of the forecasting model. On this basis, the joint forecasting of wind and solar power is carried out for wind and solar stations with significant complementarity. The prediction experiments show that compared with the single prediction of wind power and photovoltaic power, the proposed joint prediction method of wind power and photovoltaic power considering complementarity can significantly improve the accuracy of prediction, and the more significant the complementarity is, the higher the accuracy of joint prediction of wind power and photovoltaic power is.
  • Li Chuanliang, Liu Jian, Qian Minhui, Yang Dejian, Chu Xiaowei
    PDF ( )   Knowledge map   Save
    With the increasing penetration of wind power, the decrease in system inertia raises concerns about frequency stability. To fully utilize the frequency regulation potential of renewable energy, this paper proposes an optimization strategy for rapid frequency response of wind turbines based on deep reinforcement learning. Firstly, a dynamic frequency response model of wind turbines, considering the frequency regulation dead zone, is constructed using time-domain analysis. The model reveals the correlation between multiple parameters, such as the dead zone threshold, primary frequency regulation gain, and wind power penetration, and grid frequency deviation, through decoupling analysis. By this method, establish a multi-dimensional correlation quantitative characterization of frequency dynamic characteristics under the combined action of multiple parameters. Secondly, to address the challenge of identifying the optimal solution set in traditional frequency regulation methods, a dynamic parameter optimization framework based on DDPG is designed, enabling adaptive parameter adjustment through agent-environment interaction. Finally, simulations of a power system with wind turbines connected to the grid verify that the proposed strategy performs better in frequency support and adaptability than traditional parameter settings and particle swarm algorithms under different wind speeds and disturbance scenarios.
  • Li Dianpeng, Zhou Jianxing, Cui Quanwei, Fei Xiang, Wang Yuchen, Chen Feng
    PDF ( )   Knowledge map   Save
    Aiming at the problem of lubricating oil failure caused by excessive tooth surface temperature in the planetary gear system, taking the 6 MW wind turbine as the research object, and comprehensively considering the influence of factors such as the time-varying stiffness of gears and bearings on the system, a translation-torsion multi-degree-of-freedom dynamic model is constructed. Based on heat transfer theory, the tooth surface of a single-tooth model is divided into several strip regions using a differential method, elucidating the impact of different strip quantities, rotational speeds, and loads on the temperature field. Simultaneously, integrating frictional heat generation and heat dissipation characteristics, a dynamic temperature field numerical analysis model is established. The validity of the model is verified through finite element method solutions and comparison with experimental results. The findings indicate that the number of strip divisions affects the accuracy of the temperature field, with the distribution stabilizing when the number of strips exceeds 50. High-temperature regions in the temperature field are concentrated in the inner ring of bearings and gear meshing surfaces, with the sun gear exhibiting significantly higher temperature rise than that of planetary gears and the internal gear ring. The impact of temperature rise in bearings and tooth surfaces increases with rotational speed, with the rate of temperature rise gradually decreasing, showing a logarithmic relationship between temperature rise and rotational speed.
  • Xu Xinrui, Zhu Lei, Yin Fei, Wu Songxiong, Li Xiaodong
    PDF ( )   Knowledge map   Save
    This study investigates the dynamic response of a novel floating wind turbine foundation in a turbulent wind field under deep-sea conditions. Based on OpenFAST software, dynamic response analyses of the floating foundation under different turbulence intensities are conducted, and the results are compared with the traditional OC4-DeepCwind floating foundation. By coupling a multiphysics model and using the turbulent wind spectrum generated by TurbSim, the time-domain motion response of the floating foundation under wind speed of 11.4 m/s and irregular wave conditions is simulated. The results show that: 1) The turbulence intensity significantly affects the motion of the floating wind turbine; 2) The new floating foundation outperforms the traditional model in terms of motion response in surge and heave directions, with a 24.6% reduction in surge amplitude and a 0.064 m decrease in maximum instantaneous heave at 10% turbulence intensity; 3) The motion response of the new floating foundation increases linearly with turbulence intensity, with the surge maximum amplitude ranging from 5.60 m to 6.74 m, the heave amplitude ranging from 0.178 m to 0.190 m, and the pitch amplitude ranging from 0.48° to 1.10°, all meeting the design limits; 4) The maximum mooring line tension of the mooring system under the 20% turbulence intensity condition is 1.475 MN (safety factor: 4.13), and the safety factor meets the requirements of general specifications.
  • Zou Jia’nan, Cao Qimin
    PDF ( )   Knowledge map   Save
    The ERA5 wind field data from ECMWF is used to obtain an average annual wind speed of 7.4 m/s at the height of 100 m in shallow sea waters of Guangdong from 2020 to 2024, with a coefficient of variation of 0.44, indicating good wind energy stability. The average annual wind power density in shallow sea waters is 414.5 W/m², with the highest wind power density in autumn at 556.0 W/m² and the lowest in summer at 235.6 W/m², which is misaligned with the peak electricity load in summer. The average annual wind power potential in shallow sea waters is 3061×108 kW·h. Based on the grid electricity price and green power premium, the average annual economic value of wind energy ecological products in eastern Guangdong, the Guangdong-Hong Kong-Macao Greater Bay Area, and western Guangdong is 31.2 billion yuan, 42.8 billion yuan, and 66.6 billion yuan, respectively. According to the recent planned installed capacity, it is expected that the wind power generation in shallow sea waters will reach 1136×108 kW·h by 2030, accounting for only 37.1% of the total potential technological development. There is a large space for green power development and consumption. From the perspective of the planning area, the average annual wind speed and wind power density in deep sea waters are 8.5 m/s and 643.7 W/m2, which are 14.9% and 55.3% higher than those in shallow sea waters, respectively. The potential annual power generation is about 3632×108 kW·h, and the average annual power generation value can reach 167 billion yuan. It is recommended to prioritize the development of deep-sea offshore wind power in eastern Guangdong in the future.