Implementation and experimental validation of efficiency improvement in PMSM drives through switching frequency reduction

Energy efficiency improvement in variable speed motor drives is of widespread interest because of the rising cost of energy. Permanent magnet synchronous motor (PMSM) drives are especially favored in variable speed applications due to their high efficiency of operation. This research focuses on improving efficiency of the PMSM drive system by reducing the switching frequency of the inverter driving the motor. At reduced switching frequencies, programmed pulse width modulation methods that results in elimination or reduction of the low ordered sidebands of the currents are considered in this work. The study showcases new implementation aspects of programmed PWM and closed loop current control at reduced switching frequencies necessary to operate the PMSM drive system at higher efficiency. The experimental measurements validate the total system efficiency improvement at reduced switching frequencies.