APF二次脉动的指令电流放大效应及其影响

在有源电力滤波器(APF)的运用场合中,直流侧电压脉动问题非常普遍,而这种脉动问题主要以二次脉动为主。在对三相三线制非对称负载APF的研究中发现,直流侧的二次脉动会在一定程度上影响电压环,产生不必要的附加负序指令电流形成指令电流放大效应,使得APF发出的补偿电流中基波负序电流分量要大于实际非对称负载中的基波负序电流分量,进而造成网侧电流的不对称。而加入陷波器对直流侧二次脉动进行滤除后,可以有效的降低这种指令电流放大效应,使得网侧电流对称。通过仿真以及实验验证了观点的正确性。

Reference current amplification effect of secondary pulsation and its influence for APF

In application of active power filters (APF),DC side voltage fluctuation is very common and the secondary pulsation is particularly prominent in this kind of fluctuation.In the study of three-phase three-wire APF with asymmetric load,it is found that voltage loop is affected by secondary pulsation in some degree and it will generate unnecessary additional negative sequence reference current and reference current amplification effect.As a result,the fundamental negative sequence current in compensation current produced by APF is greater than fundamental negative sequence current produced by asymmetrical load,which causes the asymmetry of the network side current.After secondary pulsant suppressed by notch filter,the reference current amplification effect can be reduced effectively and the network side current will be symmetrical.The simulation and the experiments have proved the correctness of views proposed by this paper.