Leakage current analysis of three-phase inverter motor drive system with sine wave filter

Using gallium nitride (GaN) transistors in motor drive systems presents challenges because of their high dv/dt characteristics. Compared with silicon (Si) transistors, GaN transistors cause a higher leakage current in the bearing. This phenomenon results in a bearing corrosion problem in the motor, consequently shortening its lifespan. In response to these challenges, an output filter placed between an inverter and the motor has been studied recently. This paper compares the leakage current in a permanent magnet synchronous motor (PMSM) drive system driven by a GaN inverter without and with a sine wave filter. By modeling the impedance of the leakage current path, this paper confirms the possibility of reducing leakage current with the application of the sine wave filter. Experimental results show that using the sine wave filter reduces the leakage current by 32.24% at full load.