A power decoupling technique for single-stage micro inverter in ac-module application

摘要

In this paper a new power decoupling solution for mitigating double-line frequency pulsation at photovoltaic panel terminals of ac-modules is proposed. Single-stage flyback inverter, as a popular candidate due to simplicity and effectiveness, is exploited as power electronic interface. The new power decoupling circuit is integrated with DCM flyback inverter to form power processing stage of the ac-module. In addition to use smaller decoupling capacitor- compared to other power decoupling methods- proposed topology uses only 3 high-frequency switches, while two switches at the second side of the flyback transformer are switched at low frequency; thus, having negligible switching loss. An auxiliary inductor causes input voltage to vary smoothly and facilitate decoupling capacitor selection plus playing snubber role for one of high-frequency switches. Validity of proposed power decoupling strategy is verified by simulation in PSIM software.