电网电压不平衡时PWM整流器脉动控制策略研究

Study of Control Strategy to Suppress the Pulsation of Active Power and DC Side Voltage for PWM Rectifier in Unbalanced Grid Voltage

当电网电压不平衡时,PWM整流器运行的稳定性会受到严重的影响。在分析电网电压不平衡时整流器运行功率脉动原因的基础上,运用直接电流指令控制策略即向网侧注入适量的负序电流,以抑制有功功率和直流侧电压的脉动。所用算法可在无需解耦的情况下计算指令电流,使系统的控制更加简单和精准。最后,在MATLAB/Simulink中仿真验证了控制策略的正确性,并搭建PWM整流器试验平台验证了控制策略的可行性。

When the grid voltage is unbalanced,the stability of PWM rectifier operation would be severely affected.The cause of rectifier’s power pulsation under unbalanced grid voltage was analyzed.On the basis of that,a direct current command control strategy was adopted,which is to inject a proper amount of negative sequence current to the grid side to suppress the pulsation of active power and DC side voltage.This algorithm can calculate the command current without decoupling,which makes the control of the system more simple and accurate.Finally,the simulation results verify the correctness of the control strategy in MATLAB/Simulink,and the experimental platform of PWM rectifier was set up to verify the feasibility of the control strategy.