Harmonic suppression for pulsed load based on improved software phase locked loop method

  Objective   Pulsed load will inject a large number of harmonics into the ship power system. In order to perform harmonic compensation, the phase locking function of the active filter needs to be completed under severe conditions of mains voltage distortion and frequency fluctuation.

  Methods   An improved software phase locking method including harmonic suppression and adaptive voltage control is proposed. The parameters such as stability margin, dynamic response and anti-interference of the phase locked loop are optimized. Matlab simulation analysis and hardware verification experiments are carried out.

  Results   The simulation results show that the software phase-locked loop can output the correct synchronization signal under non-ideal grid conditions. The hardware experiment results show that the active power filter of the phase-locking method is applicable to the independent small-scale power grids such as ship power system.

  Conclusion   The research results can provide reference for the effective management of power quality of ship power system.