A new control method of suppressing DC-capacitor voltage ripples caused by third-order harmonic compensation in three-phase active power filters

This paper proposes a new control method suitable for active power filters to reduce the dc capacitor voltage ripples associated with the third-order harmonic current compensation. The proposed method superimposes a negative-sequence fundamental current on the compensating current to cancel out the active power ripple caused by the third-order harmonic current. As a result, the proposed method has the capability to eliminate the dc capacitor voltage ripple at double the source frequency. Experimental results obtained by a 10-kW three-phase diode rectifier verify the validity of the proposed method. The proposed method exhibits a good suppression performance of the dc capacitor voltage ripple at double the source frequency.