A novel digital current control strategy for torque ripple reduction in permanent magnet synchronous motor drives

Permanent magnet synchronous motors (PMSM) are attractive candidates in various applications because of their high efficiency, high power density, and high position resolution. In some special applications such as military and aerospace, the torque ripple percentage from PMSM has to be maintained in an acceptable level. This objective drives motivations of either optimum design of electrical machines or optimum control of motor drives. On optimum control of motor drives, injecting higher order harmonics has been a dominant technique. This paper presents a novel digital current control strategy to regulate currents with feature of fast dynamic response and easy implementation. Compared with conventional current control loop in vector control of PMSM, a bank of resonant controllers is proposed in parallel connection of PI type controllers. As a result, both fundamental and harmonic components of current can be regulated using high bandwidth digital controllers. Simulation results have verified the control effect of the proposed strategy.