Research on compound current control strategy based on LCL type active power filter

In view of contradiction between high steady state accuracy and fast dynamic response of traditional current control strategy, a novel compound current control strategy based on LCL type active power filter was proposed. The control strategy combines proportional integral control and repetitive control, the PI controller is used to ensure fast dynamic response, and further compensate control model to the stable system, which has good control characteristics in low frequency range; the repetitive controller is used to correct resonance peak and PI-inner-loop inherent phase lag of LCL filter, so as to realize fast tracking and high precision compensation on harmonic current of the power grid. The experiment results show that total harmonic distortion of the grid current is significantly reduced by compensating of shunt active power filter and the single-cycle fast response is achieved when the load changes, which verifies the compound current control strategy is effective.