为确保光伏制冷的运行性能,该文针对离网型光伏冷库采用动态等效阻抗匹配的控制策略,通过阻抗变换器进行脉宽调制输出不同占空比,使光伏发电输出与负载相匹配,构建光伏最大功率点等效阻抗与温度、辐照度和标准测试条件下最大功率点等效阻抗之间的数学模型。基于所提的控制方法,搭建一套5.4 kW的分布式光伏直驱冷库实验系统,研究表明,采用动态等效阻抗匹配的控制方法能有效改善太阳辐射波动性对光伏冷库的影响,控制后的光电转换效率、制冰量和制冷系统利用率与常规控制的系统相比同比提高41.0%、64.1%和63.5%,为光伏冷库在优化控制方面提供了理论分析及实验参考。
Abstract
To ensure the operational performance of photovoltaic （PV） refrigeration,a dynamic equivalent impedance matching （DEIM） control strategy is presented in the paper for off-grid PV cold storage. Impedance converters are used to match PV generation and load by adjusting different duty cycles with pulse width modulation （PWM）. In addition, the paper presents a model of the maximum power point （MPP） equivalent impedance for the PV system, which is influenced by temperature, irradiance, and the equivalent impedance of MPP under the standard test conditions （STC）. Accordingly, a 5.4 kW direct-driven cold storage with distributed PV system is established based on the theory and the controlling strategy. The results indicate that the DEIM can significantly reduce the impact of solar radiation fluctuation on PV cold storage systems. Compared to the condition with traditional strategy, the novel methods presented by the paper improve the values of PV modules conversion efficiency,the production quantity of ice, and the rate of refrigeration system utilization increased by 41.0%, 64.1%,and 63.5%,respectively. In addition, the paper will be a reference that provides a theoretical analysis and optimization for PV cold storage system control.
关键词
光伏阵列 /
脉宽调制 /
最大功率点 /
动态阻抗匹配 /
冷库
Key words
photovoltaic arrays /
pulse width modulation /
maximum power point /
dynamic impedance matching /
cold storage
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基金
国家自然科学基金（51966019; 51867022）; 云南省重点研发计划（201903F140013）
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