An efficiency-optimizing permanent-magnet synchronous motor drive

A permanent magnet synchronous-motor drive that uses and adaptive control to find the maximum-efficiency operating point at any speed and load is demonstrated. Active damping is provided by modulating the inverter frequency in proportion to the perturbations in the average inverter DC link current. All principal control functions, including efficiency optimization and frequency modulation, are performed by a real-time digital control algorithm, using only the filtered inverter DC link current as a feedback signal from the inverter. Laboratory tests and computer simulations demonstrate the performance of the efficiency-optimizing control and the frequency-modulation feedback loop