并联有源滤波器网侧谐波电流反馈控制

Improvement for the Closed-Loop Control of Shunt Active Power Filter Based on Feedback of Supply-Side Current

有源滤波器采用电源端电流检测的谐波抑制效果优于负载端电流检测法,但因其稳定性较差而应用较少。电源端检测方法因电源电流的反馈而构成闭环控制系统,它把产生谐振的传递函数包括在闭环内,选择适当的校正环节可以抑制谐振,通过相位超前校正可以提升系统稳定裕度和增大环路增益,但加入相位超前校正环节在提高系统的相位稳定裕度的同时系统低频段增益较低,限制了实际补偿效果。为提高低频段增益,本文提出应用选择性滤波器复合比例环节提高特定频率增益,该环节同时提高了系统相位稳定裕度和低频段的增益,保证系统稳定性并提升了补偿效果。实验结果表明了其有效性。

The active power filter based on supply-side current detection is better than load current detection in harmonic compensation,while the application is rare because it has worse stability.The system is a closed-loop system because the feedback is supply-side current,including the transfer function producing resonance in the closed-loop.Using proper correction method can suppress the resonance,and the stability margin can be improved by adding phase lead correction to the system.However,after adding phase lead correction to the system,gain of low frequency band is low while increasing the phase margin,limit the improvement of compensation effect.This paper adds selective filter and proportion link to increase gain of specific frequency,which can increase the gain of low frequency band while increasing the phase margin.Its effectiveness is verified by the experiment results.