Power loss analysis and comparision of DC and AC side decoupling module in a H-bridge inverter

In single-phase inverters, a considerable amount of low-frequency ripples appear on the DC side due to the instantaneous power imbalance between the DC side and AC side. Recently, active methods using film capacitors or inductors as ripple power storage components introduced at the DC or AC side are applied to ease this issue. Nevertheless, there is lack of research regarding the selection of DC side or AC side power decoupling. This paper investigates the power losses of key components in both AC side and DC side active power decoupling solutions and compares their performance from an efficiency perspective. The analytical power loss models are derived based on the operation principles of the active power decoupling methods. A comparative study is performed based on a 500 W single-phase H-bridge inverter study case with 400 V DC-link voltage level. The results provide a guideline to justify whether or not to apply active power decoupling methods or which active power decoupling method to choose for a given application.