GaN based transformer-less microinverter with coupled inductor interleaved boost and half bridge voltage swing inverter

Abstract

Due to their plug and play feature, easy installation, and higher power yield under partial shading conditions, microinverters have gained popularity in the roof-top-PV market. This paper explores a converter system for the transfomer-less microinverter with coupled inductor based interleaved boost as the dc-dc stage and half bridge voltage swing (HBVS) inverter as the dc-ac stage. The dc-dc stage is capable of offering high gain with a flexible choice of turns ratio of the coupled inductor but simultaneously maintaining a reduced voltage stress on the main switch. The HBVS inverter has the advantages of reduced capacitor requirement for 120 Hz power decoupling and being half-bridge derived, minimized capacitive-coupled common-mode ground currents. A 300 W GaN based inverter prototype with 30 V nominal dc input and 120 V, 60 Hz nominal ac output and operating at switching frequency of 200/100 kHz has been developed to validate the converter's operation in hardware.