Single-phase power decoupling technique utilizing Hybrid method with passive and active power decoupling

Abstract

This paper proposes a power decoupling method utilizing active and passive method to improve the power density. The active power decoupling techniques compensate the double-line frequency power ripple with a small capacitor. However, when whole power ripple is compensated by the active power decoupling circuit, the total volume becomes large due to the additional component in comparison with the passive method with large electrolytic capacitor. The proposed method limits the power ripple compensation value of the power decoupling circuit in order to reduce the buffer capacitance or peak capacitor voltage. Instead, the small electrolytic capacitor is installed on DC-link for the power decoupling capability. In this method, the DC-link capacitor is smaller than that in the passive power decoupling circuit owing to the small buffer power and the low ripple current. From the experimental result, the second order harmonics is reduced by 76.8% by the DC active filter with the small capacitor of 60 $\mu$. Finally, the power density of the DC active filter with the hybrid method is improved by 38% in comparison with the whole active power decoupling operation.