Sensorless Control of Permanent Magnet Synchronous Motor in Full Speed Range*


Aiming at resolving the limitation of the speed regulation range of sensorless control technology, a new composite sensorless control strategy is proposed to realize a control method for a permanent magnet synchronous motor (PMSM) in full speed range. In the medium- and high-speed range, the improved new sliding mode observer method is used to estimate the motor speed and rotor position information.


In the zero and low speed range, in order to avoid the defects of the sliding mode method, the rotating high-frequency voltage signal injection method is used. When switching between low, medium, and high speed, the fuzzy control algorithm is adopted to achieve smooth transitions. The simulation experiment results show that the hybrid mode combining the sliding mode observer and rotating high-frequency voltage injection methods, can effectively reduce the jitter in the algorithm switching process, and realize the smooth control of a PMSM in full speed range.


  1. PMSM
  2. Full speed range
  3. Rotating high-frequency voltage signal injection method
  4. Sliding mode observer method
  5. Fuzzy Control



Fig. 1 Schematic diagram of improved sliding mode observer


Fig. 2 The full range sensorless control waveform under the traditional weighting algorithm

Fig. 3 Full range sensorless control waveform based on fuzzy control

Fig. 4 Comparison of the speed waveforms of the two control algorithms in the switching interval

Fig. 5 Comparison of the rotor position waveforms of the two control algorithms in the switching interval


In this paper, the overall scheme design and control strategy of the PMSM sensorless control system, are studied, and the control method of motor running in the full-speed range, is analyzed in detail. The simulation and experiment results show that the low-speed high-frequency signal injection method and the medium and high-speed sliding mode observer method


can accurately estimate the rotor position and speed, and the tracking speed is fast. In the estimation process, the robustness improves. At the same time, using fuzzy control in the low-speed to medium and high-speed range, can make the PMSM switch smoothly, which has a certain application value.


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[3] Y P Zhou, G Yang, J H Yang. Speed control strategy of permanent magnet synchronous motor based on adaptive backstepping. Chinese Journal of Electrical Engineering, 2020, 15(3): 38-43.

[4] Y P Zhou , G Yang , J H Yang. PMSM speed control using adaptive sliding mode control based on an extended state observer. High Technology Letters, 2018(4): 422-433.

[5] S Q Peng , Y Y Song . Sensorless vector control of PMSM based on adaptive fuzzy sliding mode observer. Control and Decision, 2018, 33(4): 644-648.

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