An H7 Current-Source Inverter using Wide Bandgap Bidirectional Switches to Achieve High Efficiency and Low Conducted Common-Mode EMI

Abstract

Traditional current-source inverters (CSI) using silicon-based reverse-voltage-blocking (RB) switches typically have high conduction loss, low switching frequency, and bulky size. New bidirectional (BD) switches (also called four-quadrant switches) built from wide-bandgap semiconductor materials such as gallium nitride (GaN) and silicon carbide (SiC) offer both RB capability and low conduction loss that make them appealing candidates for increasing the CSI’s efficiency. This paper proposes a new modulation scheme for an emerging three-phase CSI topology (H7-CSI) to make it compatible with BD switches to achieve higher efficiency compared to the conventional H6-CSI topology. In addition, the modulation strategy combined with the topology can noticeably reduce the conducted CM EMI. Analysis, simulation and experimental results confirm the advantages of the proposed BD switch-enabled H7-CSI over conventional H6-CSIs.