Current control of PM synchronous motor in overmodulation range

This paper presents a study on a current control of a PM synchronous motor which is fed by two-level voltage source inverter in the high modulation index area. In order to increase dynamic response and extend speed limit caused by limit voltage, overmodulation methods is generally used. However, the voltage ripple in the overmodulation region generates current ripple. Because of this current ripple, the current controller with high bandwidth makes entire system unstable. In this paper, a new current controller with ripple compensation has been proposed. By the proposed method, speed dynamics can be improved and stable current control can be achieved.