Design and Implementation of a Flyback-Assisted Wide-Range Fully Soft-Switched T-Type Inverter

A novel soft-switched three-level T-type inverter is proposed in this article. The proposed inverter provides turning-
on
by zero-voltage transition and turning-
off
by zero-voltage switching (ZVS) for main switches without any voltage or current stresses. The switching energies are transferred to the snubber capacitors, so the turning-
off
process of the main switches is improved by these snubber capacitors. Besides, the auxiliary switches are turned
on
by zero-current switching and turned
off
by ZVS. Furthermore, all snubber diodes are operated by soft-switching (SS), and the proposed SS snubber cell decreases the electromagnetic interference noises. The novel snubber cell has a simple structure, ease of application, common-ground switches, and low-cost features. The theoretical analysis of the inverter is clarified, and the operating modes for steady-state analysis are presented in detail. The experimental results rated 1-kW output power and 100-kHz switching frequency are provided to justify the theoretical analysis. The proposed unique snubber cell can be easily implemented in other three-level inverters, and the practice is demonstrated in the article.