Proposal of an expert PID control strategy for current controllers in parallel active power filters

In this paper, one conventional proportional integral differential (pid) control and one new current control, for parallel active power filters (apf) design, were compared. because of the system stability constrained, the closed loop gain of the pid control is restricted. hence, in order to improve the performance of the apf, a novel expert pid current control strategy for harmonics compensation was proposed. based on the information of the control target and control rules, the current controller is designed intelligently. if the absolute value of the error trended to decrease, the pid current control keeps its maintenance; if not, then the pid current control applies strong functions. under this method, the dynamic error is reduced, and the performance of the current tracking is improved. simulated results prove the validity of the proposed method.