一种用于H7电流源逆变器的最小化开关损耗PWM新方案

Traditionally, silicon-based (Si) reverse-blocking (RB) switches are employed in current-source inverters (CSIs), but they suffer from high conduction losses, limited switching frequency, and bulky designs. In contrast, four-quadrant (FQ) switches based on wide bandgap (WBG) materials, such as gallium nitride (GaN) and silicon carbide (SiC), offer reverse-voltage-blocking capability with significantly lower conduction losses, making them attractive for efficient CSI applications. This study focuses on the H7 topology CSI, where an additional (S7) switch provides a shunting path for the DC-link current, enabling zero-current switching (ZCS) to (S1a - S6a) switches. The conventional switching schemes for the H7 topology split the zero state into four segments, leading to frequent switching transitions and elevated switching losses. A new switching scheme is proposed, which optimally arranges vectors to reduce switching transitions that eventually reduce switching losses. The effectiveness of the proposed scheme in comparison with the conventional scheme is evaluated through loss and efficiency analysis using PLECS software for various CSI topologies (3−ϕ, 400 V, 8 kW). Further, the hardware validation is conducted for the proposed switching scheme on H7 CSI using FQ switches. The experimental results are validated on a 1.2 kW laboratory prototype, demonstrating improved efficiency over conventional schemes.