Review of sensorless control techniques for PMSM drives

Permanent magnet synchronous motor (PMSM) drive systems have been increasingly applied in all kinds of high-power AC drives because of their inherent advantages of good performance, rapid dynamic response, as well as high reliability and efficiency. Precise control of the system traditionally depends on the shaft encoder, but the presence of the encoder could result in increased cost and volume, reduced reliability, etc. Therefore, the development of sensorless control techniques is important to avoid the above issues by the elimination of the sensor. Based on the running process of the motor, sensorless control techniques can be classified into four categories: initial position detection methods (IPDMs), low-speed control strategies, mid-high-speed control strategies, and full-speed control strategies. The fundamental principles, their advantages and disadvantages, the control precision, and the application range of these strategies on surface and interior permanent magnet synchronous motors (SPMSMs, IPMSMs) are described in detail in this paper. Finally, the development trend of PMSM sensorless control technologies is discussed. (c) 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.