Control of wide speed range PMSM drives with large dc-link variations without regenerative unit utilizing PWM-VSI overmodulation

In this paper the control of wide speed range PMSM (permanent magnet synchronous motor with sinusoidal excitation) is investigated, with particular attention to the low power drives equipped with PWM-VSI (PWM voltage source inverters) without regenerative unit to supply the ac power from the mains to the dc link. An algorithm is proposed to generate the optimum reference current for four quadrant operation of PMSM drive, which is fed by PWM-VSI with diode rectifier front-end. Moreover the algorithm is suitable for operation of the drive in overmodulation range, so the dynamic and steady-state performance of the system can be improved. The algorithm offers also the optimum dynamic and steady-state performance for the PMSM drive despite significant changes in dc link voltage and machine parameters. The proposed control can be easy integrated in the rotor field oriented control with or without mechanical sensors, but also in the scalar control algorithm.