双闭环控制的光伏系统多逆变器并联运行策略

Parallel Operation Strategy of Multiple Inverters in Photovoltaic System Based on Double Closed-loop Control

基于光伏电站的多并联逆变器控制技术日趋成熟,并随国内清洁能源的快速发展其应用将更加广泛。然而,多并联逆变器受设备自身容量差异、输出电压不等、接线阻抗以及测量阻抗不同将会产生系统环流。环流的增大将导致电力电子器件工作效率降低、功耗增大、寿命缩短等一系列问题。针对上述现象,此处建立了多并联逆变器数学模型,重点分析了环流产生机理、设计了相应抑制措施、提出了基于虚拟阻抗的电压、电流双闭环改进鲁棒控制策略,通过搭建的Matlab/Simulink理论模型与物理实验平台对所提方案进行了测试。结果表明,控制策略合理可行,解决了环流抑制的问题,并提高了功率分配精度,预期可为工程实践提供理论指导并具有较好地推广应用价值。

The control technology of multi-parallel inverters based on photovoltaic power plants is becoming more and more mature,and its application will become more extensive with the rapid development of domestic clean energy.However,multi-parallel inverters are subject to the difference in the capacity of the device itself,the unequal output voltage,the wiring impedance and the measurement impedance,which will cause system circulation.The increase of circulating current will lead to a series of problems such as the reduction of work efficiency of power electronic devices,the increase of power consumption and the shortening of lifespan.In response to the above phenomenon,a mathematical model is established of multi-parallel inverters,focusing on the analysis of circulating current generation mechanism,designing corresponding suppression measures and proposing a virtual impedance-based voltage and current double closed loop improved robust control strategy,the proposed scheme is tested through the built Matlab/Simulink theoretical model and physical experimental platform.The results show that the control strategy is reasonable and feasible,solves the problem of circulating current suppression and improves the accuracy of power distribution,it is expected to provide theoretical guidance for engineering practice and have good application value.