Author: Chen, Yilin Title: Automatic numerical modelling of electric machines and its applications Advisors: Fu, W. N. (EE) Degree: M.Sc. Year: 2021 Subject: Permanent magnet motorsElectric motors -- Design and constructionHong Kong Polytechnic University -- Dissertations Department: Department of Electrical Engineering Pages: [8], 53 pages : color illustrations Language: English Abstract: As permanent magnet synchronous machines for industrial use become more and more popular. This dissertation proposes a model of the outer-rotor permanent magnet synchronous motor, which has specific dimension requirements. Based on the 138mm rotor outer diameter, 104mm axial length of an iron core, the filling factor of each slot is 0.5. Its winding design used concentrated winding and double-layers. In this condition, industrial automation desires the torque of the motor is as larger as possible, and the rated speed of the motor can stay at 20 rpm and the torque wants to be 180Nm. But the simulations find out that there is an inverse proportion between torque and efficiency at an extremely small motor speed. To make the motor has 60Nm at least, considering its design parameter. This paper changes its rated speed and increases it to1000rpm to get much better performance. To ensure the correction of the model, the process of designing the model is designed by ANSYS RMxprt. In the process of design, this paper also makes a comparison with different pole slot matching as long as it is a fractional slot, and try to work out the best condition. After choosing three types of slot pole matching, which are 36 slots and 48 poles 36slots and 40 poles and 24 slots and 22 poles, as the best slot pole matching for further analysis. First of all, the paper shows the effect of a permanent magnet on the motor and studies the influence of the thickness and length of a permanent magnet on the motor torque and efficiency. And following the study of the thickness, it also studies the effect of air gap on the performance of torque and efficiency. Afterward, the study concentrates on the structure of stator slots. The slot type is chosen as pear groove type and it is divided into six parts. This dissertation chooses four parts to analyze each of them can make what impact on the rated torque, cogging torque, and efficiency. At the end of the dissertation, the motor model designed by RMxprt would be imported in Maxwell 2D to get the analysis of electromagnetic properties in two conditions. One is no load, the other is the rated load. The analysis of electromagnetic properties can be as follows, grid segmentation, magnetic flux line distribution map, and distribution of magnetic fields. In rated load condition, the motor performance can be calculated pass through the three-phase current waveform and the induced voltage diagram. After calculation, test and verify the result in RMxprt. Rights: All rights reserved Access: restricted access

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