Design of a robust current controller to position estimation error for positioning of a sensorless control of interior permanent magnet synchronous motors under high-speed drives

Abstract

This article proposes a new current controller for high-speed drives in interior permanent magnet synchronous motors (IPMSMs) with position sensorless control. It has been pointed out that the conventional current control systems become unstable under high-speed drives. First, this article shows that rotor position estimation error causes unstable current control, and this instability is especially emphasized at high speed. To overcome this instability, this article proposes a simple modified controller with 2DOF structure, the design of which is also explained. Stability, using the proposed current controller, is then analyzed theoretically, and the proposed controller can extend the stable region for IPMSM position sensorless control, which is an improvement over conventional systems. © 2008 Institute of Electrical Engineers of Japan.