A Soft-Switching Current-Fed Resonant Inverter for HFAC EV Auxiliary Electrical System

High-frequency alternating current (HFAC) power distribution systems have been widely used for many industrial occasions, including electric vehicles (EVs) received much attention. HF inverters are the core of HFAC system connected to the HFAC bus, which has an important influence on the reliability and power quality of the entire distribution system. Among the existed HF inverters, the current source resonant inverter (CSRI) has the characteristics of low current stress, good short-circuit protection, and boost conversion, which is suitable for single-stage boost conversion compared with the voltage source resonant inverters (VSRIs). However, there are still some problems such as hard switching and limited output voltage regulation ability. Regarding these limitations, an improved topology is proposed in this article. This article studies the method of realizing zero-voltage switching (ZVS) by adding bypass auxiliary capacitors, proposes an improved CLCL resonant inverter, and optimizes the CLCL resonant network to achieve wide input voltage, improved output voltage quality with high efficiency. Finally, a 250-W GaN-based inverter prototype is designed to validate the analysis.