A ZVS-PWM Scheme for Three-Phase Active-Clamping T-Type Inverters

For increasing power density and other performance of T-type three-level inverters, the soft-switching technique is studied. This article proposes a novel zero-voltage switching (ZVS) PWM scheme for active clamping three-phase T-type inverters, which can realize the ZVS operation of all switches and reduce the switching loss. The proposed ZVS PWM scheme is evolved from discontinuous PWM and modified for the requirements of T-type inverter. It enables all switches, including main switches and auxiliary switches, operate at a fixed frequency. However, a larger current on the power semiconductor devices occurs at 60 degrees zone transition. To suppress this current surge, the carriers used in the ZVS PWM scheme are phase shifted. Finally, the novel ZVS PWM scheme is verified on a 10 kW/150 kHz SiC-based ZVS T-type inverter prototype.

Automated summary

This article studies the soft-switching technique to improve the power density and performance of T-type three-level inverters. A novel zero-voltage switching (ZVS) PWM scheme is proposed for active clamping three-phase T-type inverters, which enables ZVS operation of all switches and reduces switching loss. The scheme is evolved from discontinuous PWM and modified for T-type inverters, allowing all switches to operate at a fixed frequency. To suppress current surge, the carriers used in the ZVS PWM scheme are phase shifted. Finally, the proposed ZVS PWM scheme is validated on a 10 kW/150 kHz SiC-based ZVS T-type inverter prototype.