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Title: Novel sensorless control of permanent magnet synchronous machines
Author: Liu, Jiaming
ISNI:       0000 0004 2745 4272
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2013
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This thesis is focused on the sensorless control of permanent magnet synchronous machine (PMSM) based on high frequency carrier voltage injection for zero and low speed and third harmonic back-EMF for higher speed, respectively. Differing from the conventional high-frequency carrier signal injection based sensorless controls, a new sensorless control strategy is proposed which injects a pulsating high-frequency carrier voltage into α- (or β-) axis of the stationary reference frame as stable as rotating carrier signal injection method and estimates rotor position information from the amplitude-modulated carrier current response as simple as pulsating carrier signal injection method. By injecting a high frequency square waveform carrier voltage, the bandwidth of the rotor position estimation can be significantly improved due to the higher injected frequency and removal of all filters. When the rotor speed is sufficiently high, the back-EMF based sensorless control should be applied. Third harmonic back-EMF is usually applied as reference for sensorless control since it is not sensitive to the machine and controller parameters. To improve the dynamic performance due to insufficient resolution, a speed error compensation strategy based on the continuous signal of third harmonic flux-linkage is proposed. This method also can be extended to improve the robustness and rotor position estimation in flux observer based sensorless control. Furthermore, based on Extended Kalman Filter (EKF), rotor position can be derived without considering speed even with poor quality signals for single and dual three-phase PMSM. Third harmonic back-EMF based sensorless control also has some restrictions. In salient pole machines, the winding inductance varies with the rotor position which will introduce estimation error. With imbalanced machine parameters, the measured triplen harmonic back-EMF will contain certain fundamental components which will deteriorate the rotor position estimation. By compensating the contained fundamental distortion in advance, the steady-state and dynamic performance of single and dual three-phase PMSM can be remarkably improved with high robustness.
Supervisor: Zhu, Zi-Qiang Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available