Adaptive Variable Switching Frequency Control for SiC-based PMSM Drive Systems

As global demand for hybrid/electric vehicles continues to rise, the efficiency analysis and improvement of traction motor drive systems, including the global drive efficiency, become more pressing. This paper investigates the impact of incorporating constant switching frequency pulse-width modulation (PWM) and variable switching frequency PWM (VSF-PWM) on the efficiency of a motor drive system based on a permanent magnet synchronous motor. The system also considers the use of silicon carbide metal-oxide semiconductor field-effect transistors. Furthermore, an adaptive VSF-PWM control scheme is presented to analyse the dynamic performance of the drive system, whereby the rotor speed and load torque change, allowing for improved system performance. Simulation results and the methodology for the proposed approach are presented. By applying the VSF-PWM method, system efficiency is significantly improved without introducing negative effects on the harmonic quality of currents, and can be improved up to 3% at specific operating conditions.