Development of Three-Phase Synchronous Permanent-Magnet Motors and Drives for Low Speed and High Torque Applications

• Main Authors: Xie-Jun Lu, 盧協駿
• Other Authors: Jonq-Chin Hwang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/tmqu46

碩士 === 國立臺灣科技大學 === 電機工程系 === 107 === This thesis presents the design and control of three-phase permanent magnet synchronous motor for low-speed and high-torque applications. The multi-pole structure of internal rotor type is installed by inset permanent-magnet, while the three-phase windings of the stator is concentrated winding. The electromagnetic analysis software JMAG is used to analyze the distribution of magnetic flux density and no-load induced voltage of the permanent magnet synchronous motor. Hence, the design of geometric dimensions and core of the designed motor and neodymium-iron-boron magnet is carried out. The parameters and performance of the designed motor are measured and confirmed by a measurement platform. As for the drive system design for the designed motor, the rotor position is estimated by three digital Hall-effect sensors. When the motor starts to run, the rotor position is discontinuous, and the unit six-step square wave is generated, while the rotor position is continuous, and the unit sine wave is generated when the motor runs in the steady-state. The unit waves are switched by control strategy of current closed loop. During transient state to run, the current control is based on six-step square wave. When the motor runs in the steady-state, the current control is switched current closed loop control of quadrature and direct axis coordinate system. By using this control strategy, the overall efficiency of the system is the best. In the experiment tests, the peak value of induced voltage and harmonic distortion measured are 113V and 1.30% repectively, and the rotor flux linkage is 0.3382 , whereas the equivalent resistance of each phase is 1.0159 , and the equivalent inductance of each phase is 10.02 mH which is measured by the load analysis of the generator mode. When the speed command is 150 rpm and the load torque is 35.6 N-m, the maximum phase current of phase A of the motor is 4.8 A, the quadrature-axis current is 3.53 A, the direct-axis current is 0.05 A, and the overall system efficiency is 84.4%. The measured results are close to the analytical results, which verifies the feasibility of this thesis.