Soft‐switching SiC Three‐phase Four‐wire Back‐to‐back Converter

This chapter introduces a soft‐switching silicon carbide (SiC) three‐phase four‐wire back‐to‐back (BTB) converter. A three‐phase four‐wire BTB converter composed of a front‐end pulse‐width‐modulation (PWM) rectifier and a load‐side PWM inverter is widely used in alternating current sources, uninterruptible power supply, motor drives, and micro‐grids. The rectifier and the inverter in the zero‐voltage‐switching (ZVS) BTB converter share one auxiliary circuit to realize the ZVS operation of all the switches. In the converter, the current commutation of each leg in one switching period depends on the PWM scheme and the filter inductor current polarity. A short‐circuit stage is designed to achieve the ZVS condition. The resonant parameters are critical for the performance of the ZVS converter. The loss distribution of the ZVS BTB converter is different from that of the traditional BTB converter. The operation principle of the ZVS BTB converter is verified on a 9 kW prototype with SiC metal‐oxidesemiconductor field‐effect transistor devices.