Recent Developments in Position Sensorless Control Strategies for PMSM Drives

Abstract: (Sponsored by PELS TC 3) Under certain extreme operating conditions, such as harsh high-temperature environments or limited installation space, the use of position sensors such as encoders or resolvers may become impractical or unreliable. Consequently, position sensorless control has emerged as a promising solution for permanent magnet synchronous motor (PMSM) drive systems. In the zero- and low-speed regions, position sensorless algorithms based on inductance saliency typically rely on high-frequency (HF) signal injection into the motor drive system. Rotor position information is then extracted from the resulting HF current responses using digital filtering techniques, which inevitably introduce phase delay during the filtering process. For middle- and high-speed operation, model-based observers are widely employed to estimate the extended back electromotive force or active flux, both of which inherently contain rotor position information. This webinar will present recent advances in position sensorless control methods for PMSM drives, covering techniques applicable to different operating speed regions. In the first segment of this webinar, a filterless position sensorless control method for low-speed operation will be introduced. In addition, a comprehensive compensation strategy, including resistance phase-shift balancing and residual phase-shift cancellation, will be discussed to further enhance position estimation accuracy. In the second segment, advanced observer-based approaches (e.g., under varying operating speeds and in the presence of disturbances such as high-order harmonics, negative-sequence components, and inverter nonlinearities) will be presented to enhance position estimation performance.