基于补偿电流的并联逆变器环流抑制方法
A Method of Suppressing Circulating Current for Parallel Inverters Based on the Compensating Current
-
摘要: 为了提高并网逆变器的并联运行效率和特性,需对并联运行的逆变器进行环流抑制。本文基于补偿电流法的平均电流控制的逆变器并联系统,对补偿电流的位置及调节函数进行优化,使其响应的时间常数小,均流效果不受PI调节器相移和滞后作用的影响,基波环流抑制效果更好;考虑到补偿电流法主要抑制基波环流,将补偿电流经过低通滤波器,使得补偿电流中只含有基波电流分量,消除补偿电流中谐波分量对环流抑制的影响。外部采用LCL滤波器对高频谐波环流进行抑制。仿真结果表明本文给出的基于补偿电流法的平均电流控制对抑制基波环流的优越性及LCL滤波器对抑制高频谐波环流的有效性。Abstract: For improving the efficiency and characteristics of parallel grid inverter, the suppression of circulating current is needed. A parallel inverters system of average current control based on the compensating current control method is studied in this paper, in which the position and adjusted function of compensating current are optimized to make its response time constant small and current averaging effect not influenced by the delay and phase shift of the PI regulator, and it has better suppressing effect of fundamental circulating current. For the compensating current method is mainly used to suppress the circulation of fundamental circulating current, the low pass filter is applied to eliminate the effect of harmonic current in compensating circulation current, which make fundamental current component only be included in compensating current. While the high frequency harmonics circulation is suppressed by using LCL filter. The simulation results show that the proposed average current control scheme based on compensating current has superiority for suppressing fundamental circulating current, and LCL filter has the validity to suppress the high frequency harmonics circulation.