A new active power decoupling technique for three-port flyback inverter

In this paper, new decoupling technique for three-port flyback inverter using active power decoupling circuit with auxiliary winding and novel switching pattern is proposed. Conventional passive power decoupling method is applied to control Maximum Power Point Tracking (MPPT) efficiently by attenuating double frequency power pulsation in photovoltaic (PV) side. However this type of power decoupling capacitor for flyback inverter is fairly large so electrolytic capacitor is essentially required. Large value of electrolytic capacitor makes some problem that is bulky size and short lifetime. Because this huge input capacitor is strongly concerned with life-span of AC module system, active power decoupling circuit minimizing input capacitance is needed. From the proposed topology, auxiliary winding defined as ripple port will partially cover surplus pulsation power, so input capacitor and auxiliary capacitor is reduced as it can be replaced film capacitor. To perform the operation of charging/discharging decoupling capacitor Cx, novel switching sequence is also proposed and verified by simulation.