Robust Current Regulator with 2 DOF Structure and Stability Analysis for IPMSM Drives under High Speed Region

This paper proposes a new current regulator for IPMSM sensorless drives under high speed region. It has been pointed out that the conventional current control system for IPMSM becomes unstable under high speed region, which caused by position estimation error. First, this paper shows that this phenomenon is caused by position estimation error, and this instability is especially emphasized under high speed region. To overcome this instability, two degrees of freedom (2 DOF) controller is proposed in this paper. Stability using the proposed current regulator is then analyzed theoretically, and the proposed controller can enlarge stable region of position sensorless control for IPMSM drives, which can conclude that the proposed controller is superior to that using conventional one