CONTROL STRATEGY OF VSG-SST UNDER UNBALANCED VOLTAGE CONDITION

Cheng Jing; Zhao Zhenmin; Zhang Ling; Nan Dongliang

doi:10.19912/j.0254-0096.tynxb.2022-0137

PDF(5936 KB)

Acta Energiae Solaris Sinica ›› 2023, Vol. 44 ›› Issue (3) : 393-400. DOI: 10.19912/j.0254-0096.tynxb.2022-0137

CONTROL STRATEGY OF VSG-SST UNDER UNBALANCED VOLTAGE CONDITION

Cheng Jing^1,2, Zhao Zhenmin^1,3, Zhang Ling³, Nan Dongliang^1,3

Author information +

History +

Abstract

When the low-voltage distribution network voltage is unbalanced, the generated negative sequence component will cause current unbalance and power oscillation in the solid state transformer (SST) output stage in the traditional virtual synchronous generator (VSG) control. Therefore, this paper proposes a T-type three-level output stage joint control strategy based on VSG to improve output stage power quality. Firstly, the mechanism of VSG current unbalance and power oscillation under unbalanced voltage is analyzed. Secondly, based on VSG control algorithm and instantaneous power theory, a new current reference generator is designed, which realizes cascade control with positive and negative sequence current regulator. This ensures the SST output current balance and constant active/reactive power, and realizes reliable switching of different operating conditions. Finally, the separation method of positive and negative sequence components and the midpoint potential balance algorithm are analyzed and researched, and the control strategy is simulated and verified. The results show that the proposed joint control strategy is effective and feasible, and can guarantee the quality of the grid-connected current and power of the SST output stage under three-phase unbalanced voltage conditions.

Key words

power quality / solid state transformer / virtual synchronous generator / T-type three-level / unbalanced grid voltage / control strategy

Cite this article

EndNote

Ris (Procite)

Bibtex

Download Citations

Cheng Jing, Zhao Zhenmin, Zhang Ling, Nan Dongliang. CONTROL STRATEGY OF VSG-SST UNDER UNBALANCED VOLTAGE CONDITION[J]. Acta Energiae Solaris Sinica. 2023, 44(3): 393-400 https://doi.org/10.19912/j.0254-0096.tynxb.2022-0137

References

[1] 盛万兴, 吴鸣, 季宇, 等. 分布式可再生能源发电集群并网消纳关键技术及工程实践[J]. 中国电机工程学报, 2019, 39(8): 2175-2186.
SHENG W X, WU M, JI Y, et al.Key techniques and engineering practice of distributed renewable generation clusters integration[J]. Proceedings of the CSEE, 2019, 39(8): 2175-2186.
[2] 梁得亮, 柳轶彬, 寇鹏, 等. 智能配电变压器发展趋势分析[J]. 电力系统自动化, 2020, 44(7): 1-14.
LIANG D L, LIU Y B, KOU P, et al.Analysis of development trend for intelligent distribution transformer[J]. Automation of electric power systems, 2020, 44(7): 1-14.
[3] 李子欣, 高范强, 赵聪, 等. 电力电子变压器技术研究综述[J]. 中国电机工程学报, 2018, 38(5): 1274-1289.
LI Z X, GAO F Q, ZHAO C, et al.Research review of power electronic transformer technologies[J]. Proceedings of the CSEE, 2018, 38(5): 1274-1289.
[4] 刘维, 涂春鸣, 兰征, 等. 具有同步电机特性的电力电子变压器[J]. 电网技术, 2016, 40(3): 918-924.
LIU W, TU C M, LAN Z, et al.Power electronic transformers with synchronous generator characteristics[J]. Power system technology, 2016, 40(3): 918-924.
[5] 艾欣, 荣经国, 吕正, 等. 一种新型的能量路由器结构及其控制策略的研究[J]. 电网技术, 2019, 43(4): 1202-1210.
AI X, RONG J G, LYU Z, et al.Research on structure and control strategy of a novel router[J]. Power system technology, 2019, 43(4): 1202-1210.
[6] 钟庆昌. 虚拟同步机与自主电力系统[J]. 中国电机工程学报, 2017, 37(2): 336-348.
ZHONG Q C.Virtual synchronous machines and autonomous power systems[J]. Proceedings of the CSEE, 2017, 37(2): 336-348.
[7] TANG S, WANG W J, LI S, et al.Research on control technology of distributed power generation virtual synchronous generator[J]. IOP conference series: earth and environmental science, 2021, 657(1): 1-9.
[8] 李振, 吕志鹏, 盛万兴, 等. 基于虚拟同步电机控制的固态变压器对多控制类型分布式电源接入的适应性分析[J]. 电力自动化设备, 2020, 40(9): 80-87.
LI Z, LYU Z P, SHENG W X, et al.Adaptability analysis of VSM controlled SST to distributed generation with multiple control types[J]. Electric power automation equipment, 2020, 40(9): 80-87.
[9] WANG C P, YU X J, LI H T.Research on the structure and control strategy of energy storage grid connected inverter[J]. IOP conference series: earth and environmental science, 2021, 012032(1): 1-8.
[10] AFONSO J L, TANTA M, PINTO J G O. A review on power electronics technologies for power quality improvement[J]. Energies, 2021, 14(24): 8585.
[11] 涂春鸣, 杨义, 肖凡, 等. 非线性负载下微电网主逆变器输出侧电能质量控制策略[J]. 电工技术学报, 2018, 33(11): 2486-2495.
TU C M, YANG Y, XIAO F, et al.The output side power quality control strategy for microgrid main inverter under nonlinear load[J]. Transactions of China Electrotechnical Society, 2018, 33(11): 2486-2495.
[12] 孙伟莎, 程启明, 程尹曼,等. 不平衡电网电压下MMC滑模变结构控制策略[J]. 太阳能学报, 2020, 41(9): 310-317.
SUN W S, CHENG Q M, CHENG Y M, et al.MMC control strategy based on sliding mode variable structure under unbalanced grid voltage[J]. Acta energiae solaris sinica, 2020, 41(9): 310-317.
[13] 黄倩, 袁旭峰, 陈明洋, 等. 基于DSOGI的不平衡负载补偿策略研究[J]. 电测与仪表, 2021, 58(3): 126-130.
HUANG Q, YUAN X F, CHEN M Y, et al.Research on compensation strategy of unbalanced load based on DSOGI[J]. Electrical measurement and instrumentation, 2021, 58(3): 126-130.
[14] 郑诗程, 胡青松, 彭勃. T型三电平拓扑及其中点电位平衡控制策略[J]. 电力系统及其自动化学报, 2017, 29(12): 63-68.
ZHENG S C, HU Q S, PENG B.T-type three-level topology and control strategy for its neutral-point voltage balance[J]. Proceeding of the CSU-EPSA, 2017, 29(12): 63-68.
[15] HUANG H H, DING C, LI E W.Modified DPWM method for vienna rectifier considering current harmonic distortions reduction and neutral point potential balance[J]. IEEJ transactions on electrical and electronic engineering, 2020, 15(12): 1205-1212.