Active power decoupling using bi-directional resonant converter for flyback inverter without electrolytic capacitor of PV AC module system

Recently, AC module system in photovoltaic (PV) generation, mismatch problem between AC power which fluctuates continuously and constant input power has been occurred. To solve this problem, power decoupling techniques are required. These techniques are connecting electrolytic capacitors of a large capacitance in parallel to PV input power to reduce voltage ripple of input voltage. But, electrolytic capacitor has disadvantages of low lifespan and weakness in high temperature. For long life span AC module system, the electrolytic capacitor should be replaced to a film capacitor. This paper proposes active power decoupling method using bi-directional resonant converter (APD-BRC) for flyback inverter. Since voltage ripple of input voltage is reduced, electrolytic capacitor can be replaced to film capacitor. APD-BRC circuit is composed of a bi-directional buck-boost converter using soft-switching techniques. The proposed topology is verified by simulation and experimental results.