Research On Sensorless Detection And Control Of Bearingless Synchronous Reluctance Motor

A bearingless synchronous reluctance motor(BSRM) is a kind of simple structure、 distinctive and outstanding motor. BSRM not only has some advantages of a synchronous reluctance motor, such as simple structure, small size, low cost, no excitation windings or permanent magnet on the rotor, etc., but also has excellent characteristics of magnet bearings, such as no friction, no lubrication, no pollution and long life-span. Compared with other types of bearingless motor, BSRM can easily achieve high speed, high torque density because of its high saliency ratio. And it’s more suitable for high speed and high precision fields or occasions, such as aerospace, defense and military. So BSRM has wide application prospects and a wealth of research value.Sponsored by National Natural Science Foundation of China(60974053) and “333 project” of Jiangsu Province, two degrees of freedom BSRM was used as the research object of this dissertation to analyze and study the basic structure, the mathematical model, sensorless self-detection technology(speed sensorless and displacement sensorless), digital control system and experimental platform. The main work is as follows:Firstly, research background of bearingless motors has been introduced detailedly. Furthermore, research status and the development trends of bearingless motors and application prospects were expounded. Then, the generation principles of BSRM torque and radial suspension force were explained. Finally, the mathematical model of BSRM torque subsystem and radial suspension force subsystem were derived respectively, according to the principle of magnet circuit and the principle of field virtual displacement.Secondly, the technology of phase-locked loop(PLL) was introduced, and applied to BSRM. In this dissertation, a novel method for speed self-detection using PLL was proposed. And then, a speed sensorless of BSRM based on PLL was designed. At last, the reliability of the system was validated by simulation and experiment studies. The results have shown that the proposed method is able to identify the rotor position or angular velocity precisely, and the control system has good capability of anti-interference.Furthermore, the dissertation has taken the object of the inductance matrix of BSRM to continue the thorough research. With Ansoft finite element analysis software, the accuracy of mathematical model of BSRM radial suspension force subsystem has been verified. Finally, according to the relationship between inductance of two sets of stator windings with rotor radial displacement, the displacement self-detection method was deduced. Then, the corresponding control system was built and the simulation model was constructed in Matlab/Simulink to verify the proposed method. Simulation results demonstrate the correctness and reliability of the displacement self-detection method.Finally, the hardware and software of digital control system of BSRM have been given. And the experimental platform was built and debugged. Some related experiments have been carried out to verify the reliability of the experimental platform.