Overview of Double-Line-Frequency Power Decoupling Techniques for Single-Phase Z-Source/Quasi-Z-Source Inverter

The power decoupling strategies of single-phase Z-source/quasi-Z-source inverter (ZSI/qZSI) to handle the inherent double-line-frequency (2 omega) power are overviewed. They are categorized as passive and active power decoupling methods. The former suppresses the 2 omega ripple by the impedance network, modified modulation methods, or closed-loop damping control. The latter diverts the 2 omega ripple to the compensation capacitor of integrated active power filters, through properly operating a half-bridge phase leg. The pros and cons of those 2 omega power decoupling methods are discussed and recommendations are given for future development of such single-phase inverters.