有源电力滤波器补偿延时及对策的研究

由谐波电流指令计算及PWM控制引起的补偿延时影响了有源电力滤波器的补偿性能,本文分析了在全数字控制及模数混合控制两种控制方式下产生时间延迟的原因,最后给出了实现无差控制的条件.在此基础上提出了一种简单的相位补偿方法,采用该方法可以有效地补偿谐波电流指令计算及PWM控制引起的时间延迟,同时保证有源电力滤波器具有良好的动态性能.最后通过实验验证了采用新方法的有源电力滤波器无论对稳定负载还是变化的负载都具有良好的补偿效果.

Study on the compensation delay and its countermeasure of active power filter

The effect of compensation delay, which is caused by compensation reference calculation and current control, on the performance of active power filter (APF) is analyzed. It can be seen that the compensation of high order harmonics is degraded seriously by even small time delay. The reason causing time delay is analyzed in case of digital control and digital-analog hybrid control. Then the current control method without compensation error is figured out. On this basis, a simple and effective phase compensation method is presented to compensate the time delay caused by compensation reference calculation and current control. Moreover, a simple predictor is implemented to improve the dynamic performance of APF, which essentially does not increase the complexity of calculation. Finally, testing results on an experimental shunt APF are presented to validate the proposed method.