具有电压前馈的两级式逆变器的稳定性分析

Stability Analysis of Two-stage Inverter With Voltage Feedforward

针对两级式逆变器因负载突变引起的电压不稳定问题,提出了带有电压前馈和有效值反馈比例积分(PI)补偿器控制两级式逆变器运行。前级变换器采用有源超前滞后补偿器的电压环控制直流母线电压稳定。基于小信号数学模型,给出了前级变换器闭环输出阻抗和后级变换器闭环输入阻抗,并引入Dr.Feng判据分析了两级式逆变器在空载和满载下的稳定性。根据Dr.Feng判据的分析结果,推出在电压前馈和有效值反馈PI补偿器控制下,两级式逆变器可实现空载和满载切换运行。最后,通过仿真和实验结果的分析,充分证明了该控制方式的可行性和有效性。

A two-stage inverter with voltage feedforward and root-mean-square feedback proportional integration(PI)compensator is proposed to control the voltage instability of the two-stage inverter caused by load mutation.The voltage loop of the active lead lag compensator is used to control the voltage stability of the DC bus in the front converter.Based on the small-signal mathematical model,the closed-loop output impedance of the front converter and the closed-loop input impedance of the back converter are given.The stability of the two-stage inverter under no-load and full-load conditions is analyzed by introducing Dr.Feng criterion.According to the analysis results of Dr.Feng criterion,it is deduced that the two-stage inverter can switch between no-load and full-load under the control of voltage feedforward and virtual value feedback PI compensator.Finally,the feasibility and effectiveness of the control method are fully proved through the analysis of simulation and experimental results.