Complex control strategy of parallel hybrid active power filter

A complex current control strategy is put forward, which combines the generalized integral PI controller with the feedforward control algorithm of specified harmonic elimination based on virtual inductor. The basic principle of feedforward controller is: The APF is controlled as a virtual inductor at specified harmonic frequency and it resonates together with PF to provide a low impedance path for harmonic current with good dynamic performance. The feedforward controller has strong dependency on PF parameters and it is difficult to ensure the control precision. The generalized integral PI controller can compensate the specified harmonic without static error, but it needs several cycles to precisely track the harmonic current. The proposed strategy has both better dynamic performance and smaller static error, and compensates harmonic individually. Experimental results verify it is feasible and effective.