A Single-Phase Soft-Switching Buck-Boost Inverter

This article presents a single-phase, single-stage unidirectional inverter derived from a non-inverting buck-boost dc/dc converter combined with a full bridge unfolder circuit. Three different operating modes to achieve zero-voltage switching (ZVS) are discussed and evaluated against each other, demonstrating the feasibility of a soft-switching operation for this converter. The circuit structure and operating principles are discussed in detail. A modular 400 W prototype utilizing GaN devices switching at 500 kHz was built to verify the design, using an input dc voltage range of 100 V to 400 V and delivering an ac output voltage of 230 V at 50 Hz.