两并联三相PWM整流器零序环流抑制与均流控制

摘要

The mathematical model of two parallel three-phase PWM (Pulse Width Modulation) rectifiers is established,and the influence of system parameters on the zero sequence circulating current is analyzed in detail.The dual-loop control system for output current balance and circulating current suppression is designed.Based on adjusting zero vector principle,a seven-stage symmetrical SVPWM (Space Vector Pulse Width Modulation) control strategy is presented,and a minimum beat zero sequence circulating current suppressor is designed to suppress the circulating current by adjusting the zero vector in real time.The inner current loop applies the current decoupling feedforward control strategy to achieve unity power factor,and the outer voltage loop applies the common voltage PI regulator to achieve output current balance control.There is no communication between the parallel modules,and the control methods are simple and reliable.Simulative and experimental results show that,the minimum beat circulating current suppressor can effectively suppress the circulating current,and the designed control strategy can eliminate the interference of inductance unbalance on the two parallel three-phase PWM rectifiers and achieve the control of the circulating current and current balance.%以两并联三相脉宽调制(PWM)整流器为研究对象,建立了系统的数学模型,详细分析了系统参数对零序环流的影响,设计了两并联三相PWM整流器的环流、均流双闭环控制系统,提出了一种调零矢量空间矢量脉宽调制(SVPWM)环流抑制策略,并设计了一种基于最小拍算法的零序环流抑制器,通过对零矢量的实时调节实现系统环流的抑制.电流内环采用电流解耦前馈控制策略,实现了单位功率因数,电压外环采用公共电压PI调节器实现均流控制,并联模块间不需要通信,控制简单、可靠.仿真与实验结果表明:最小拍环流抑制器能有效地抑制环流,所设计的控制方案消除了电感参数不一致对两并联三相PWM整流器的影响,实现了环流、均流控制.