H-type symmetrical distributed capacitor power decoupling circuit

Abstract

Single-phase inverters have inherent double frequency problems, which are likely to cause system instability. In this paper, it does not add additional switching devices while retaining the four switching devices of the H-bridge. This topology only needs to split the original filter capacitor on the AC side into two symmetrical connections and can cancel additional DC side support capacitors. For this topology, the fundamental frequency common-mode voltage injection is used to avoid additional low-frequency harmonics derived from the DC side. Theoretical analysis and experiment explain the working principle of the topology. The result proves that this topology can effectively buffer the double frequency of the system without additional switching devices.