Novel DC to single-phase AC isolated current source inverter with power decoupling capability for micro-inverter system

This paper discusses a circuit configuration for a single-phase current source inverter that features power decoupling capability. This converter consists of a resonant type isolated DC/DC converter, power decoupling circuit, and a current source inverter (CSI). The proposed converter can be achieved the low input voltage ripple without a large smoothing inductor or electrolytic capacitor. In this paper, the fundamental operation of the proposed circuit is confirmed by simulation and experiment. From the simulation results, the fundamental operation is conformed. In addition, the Pulse Density Modulation (PDM) is applied on the active buffer and inverter control. As a result, the each switching devices are switched at zero current period. Thus, the zero current switching is achieved. Moreover, the maximum efficiency is 93.5% when the output power is 280 W. From the experimental results, the input voltage ripple fluctuation is reduced by 1.2% by proposed control. In addition, the Total Harmonic Distortion (THD) of the inverter output current is 2.9%.