多并网逆变器耦合谐振特性

针对多LCL滤波型并网逆变器并联并网系统的复杂耦合谐振问题,建立单台逆变器的数学模型,并扩展成多台逆变器并联系统的数学模型.考虑逆变器自身、并联逆变器和电网单独作用时的等效电路模型,提出一种基于叠加定理的多逆变器并联系统小信号等效简化电路.利用频域分析法仿真分析了多逆变器并联的耦合谐振特性,并与单台逆变器谐振特性进行了对比分析,结果表明,多逆变器并联系统会出现额外的谐振尖峰,且谐振峰值和频率与并联逆变器的数量有关.

Coupling resonance characteristics of multiple grid-connected inverters

In order to solve the complex coupled resonance problem for the parallel grid-connected system of grid-connected inverters with multiple LCL filters, the mathematical model for single inverter was established, which was extended to form the mathematical model for the multiple inverter parallel system. With considering the equivalent circuit model when the inverter itself, parallel inverter and grid separately functioned, a small signal equivalent simplified circuit of multiple inverter parallel system based on the superposition theorem was proposed. With the frequency domain analysis method, the coupling resonance characteristics of multi inverters in parallel were analyzed, which were compared with the resonance characteristics of single inverter. The results show that an additional resonance peak will occur in the multiple inverter parallel system, and the resonance peak value and frequency are related to the number of parallel inverters.