An Improved Hybrid ZVS Modulation for SiC High-Frequency Three-Phase Inverter

In recent years, SiC three-phase inverters have been widely used in aviation electric propulsion systems due to their advanced performance. However, some challenges remain, such as the power loss at high-frequency switching and difficulty in further improving efficiency. To solve this problem, we proposed an improved hybrid zero-voltage switching (ZVS) modulation for the high-frequency SiC three-phase inverter. It combines the variable current band control with the clamping modulation to achieve the ZVS during the full-line cycle, to further improve the efficiency. In this article, the control target of about 120° clamp per phase and the soft-switching resonant period are analyzed in detail, and the variable current band is discussed. Still, the transient process of switching between the clamping mode and the high-frequency modulation mode is presented, which minimizes the additional power loss. Finally, a 5-kW/250 kHz proof-of-concept prototype was built and it can realize a peak efficiency of 98.88%, and the efficiency of the proposed method can be increased by 0.38% compared with existing similar modulation. All theoretical analyses and proposed modulation strategies are verified by the designed prototype.