Position Sensorless Permanent Magnet Synchronous Machine Drives—A Review

Owing to the competitive advantages of cost reduction, system downsizing, and reliability enhancement, position sensorless control methods for permanent magnet synchronous machine drives have drawn increasing attention from academia to industrial applications. In this article, a survey of the major sensorless control techniques for a wide speed range from low to high speeds is presented. The different high frequency signal injection schemes, fundamental pulsewidth modulation excitation methods, and model-based sensorless control are displayed and compared, which is able to facilitate the sensorless control implementation.