Design and Research on Power Decoupling Module in Single-Phase H-Bridge Inverter

In single-phase converters, the imbalance of AC side and DC side instantaneous power will cause the appearance of low-frequency ripple in DC side and reduce the reliability of the converter systems. In this paper, a bridge arm and a pair of capacitor as power decoupling module was added in H-bridge inverter, the decoupling theory and capacitor selecting principles of the decoupling module was studied either placing in inverter DC side or AC side. Through analysis of voltage and current stress in both topologies, the influence of the decoupling module on H-bridge inverter and the selection of module capacitor on module voltage and current stress is analyzed. The flow path of double-line frequency ripple current illustrates the decoupling effect of power decoupling module. Simulations are performed to validate the rationality of the analysis providing theoretical basis for design and application of the decoupling module.