Comparative Study of Permanent-Magnet Synchronous Motor Drives: Two-level GaN-Based and Three-level Silicon-Based Voltage Source Inverters

Gallium Nitride (GaN) transistors, which fall into the category of Wide-bandgap semiconductors, have higher switching capability and typically smaller conduction losses in low voltage when compared to traditional Silicon (Si)-based MOSFET counterparts. Due to these promising features, they are progressively becoming popular in power electronics applications including motor drives. Permanent-Magnet synchronous motors (PMSMs) are gaining significant interest in many drive applications due to their several advantages including high efficiency, high power density, and reduced weight and size. This paper discusses the application of two-level (2L) voltage-source inverter (2L-VSI) with GaN switches and three-level VSI (3L-VSI) with high-end MOSFET switches in PMSM drive systems and compares them in terms of switching performance, power loss, efficiency, and the voltages generated at the PMSM terminals through considering the detailed models of the semiconductor switches. Moreover, the overvoltage and high dv/dt effects due to the connecting cables between VSI and PMSM are studied and a solution to reduce these negative effects is investigated. Simulations carried out using PSIM software are presented.