Abstract:

The synchronization signal will be not accurate when the three-phase voltage is unbalanced or distorted,which results in the bad control effect for active power filter.Therefore this paper proposed a new software phase-locked loop based on adaptive filter.The improved adaptive filter has the advantages of fast dynamic response and high steady-state accuracy.It can remove the AC component out of the u_q when the three-phase voltage distorted.Consequently,it eliminates the judder of frequency and phase.Then the new method can provide the accurate synchronization signal.The simulation and experiment results show that the algorithm is effective to get the synchronous signal for active power filter.It can improve the compensation performance of active power filter.

Key words: phase-locked loop, adaptive filter, active power filter, synchronization signal