三相四线制系统中计及零序电流特性的分布式电源逆变器有功和无功功率控制

Active and reactive power control with zero sequence current characteristics for distributed generation inverters in three-phase four-wire system

分布式电源逆变器广泛应用于三相四线制系统,在发生接地故障时,逆变器应该实现低电压穿越的要求,另外,四线制系统下的故障零序特性不能忽略。提出一种能够同时实现以上两个目标的控制策略。基于对分布式电源逆变器控制和并网系统的故障零序电流特性分析,将逆变器的故障电流控制在最大限值内,并通过注入正负序电流消除对零序电流特性曲线产生的不利影响。最后通过实际工程算例分析,验证了所提控制策略的正确性和可行性。

Distributed generation inverters have been widely used in three-phase four-wire systems.The inverter should meet the requirements of low voltage ride through when a ground fault occurs in the grid.In addition,the fault zero sequence characteristics of the four-wire system cannot be ignored.This paper proposes a control strategy that can achieve the above two objectives at the same time.Based on the analysis of distributed power inverter control and zero-sequence current characteristics of grid-connected system,the fault current is limited to the maximum limit,and the adverse effects on the zero-sequence current characteristic curve are eliminated by injecting positive and negative sequence currents.The actual engineering examples are analyzed to verify the correctness and feasibility of the proposed control strategy.