摘要
本研究建立四極14槽永磁直流有刷馬達之模擬技術，以有限元素軟體(Ansys Maxwell)分析馬達的性能，主要探討移刷對馬達之影響、實現馬達高低速檔位之運行與降低頓轉扭矩之方法。最後使用有限元素軟體(Ansys Mechanical)進行分析馬達運轉時所產生之電磁激振力與輻射至空氣中的噪音。 結果顯示移刷之方向及角度均會影響馬達之性能，碳刷偏移的設計建議移至馬達因電樞反應所產生新磁中性面上，這樣的方式會使整體效率提升。在設計馬達高低速檔位，是透過碳刷偏移的方式來降低電樞有效導體數，偏移角度越大，電樞有效導體數則越低，而碳刷偏移方向會與馬達旋轉方向相反，主要原因與電樞反應有關。因此當碳刷偏移時，堵轉扭矩會降低，額定扭矩則上升，所以在相同負載之情況時，轉速將會提升。在降低頓轉扭矩之研究中，本文透過四種方法來降低頓轉扭矩，分別為改變磁石展開比例、氣隙寬度、磁石圓心偏移量、轉子槽開口大小，透過這些方式都能夠降低頓轉扭矩，但也會同時改變馬達性能，因此在降低頓轉扭矩的同時也要特別注意性能之變化。在電磁噪音的研究中，其噪音產生之頻率主要與馬達極對數、槽數及轉速有關，其中最嚴重的噪音階次為極對數與槽數乘積的倍數，分別為28階、56階與84階。
並列摘要
This study establishes the simulation technology of a four-pole 14-slot permanent magnet DC brush motor. Firstly, analyzes the performance of the motor utilizing a finite element software (Ansys Maxwell). The focus is put on discussing the influence of brush position on the performance of motor, the operation of the high and low speed of the motor, and the countermeasure to reduce the cogging torque. Secondly, the finite element software (Ansys Mechanical) is used to analyze the electromagnetic excitation force generated by motor operation and the noise how to radiate and propagate into the air. The results show that the direction and angle of the brush-moving affects the performance of the motor, the design of the brush movement is recommended to move to the new magnetic neutral surface of the motor due to the armature reaction, which will increase the overall efficiency. While designing the high and low operation positions of the motor, the number of effective conductors of the armature is reduced by increasing the angle between two brushes. When the angle is increasing, the number of effective armature conductors is decreasing. Besides, the carbon brush movement direction is opposite to the motor rotation direction. Therefore, when the brush angle is increasing, the stall torque will decrease and the rated torque will rise, so the speed will increase under the same load. In the study of reducing the cogging torque, the work uses four methods to reduce the cogging torque, i.e. change the magnet expansion ratio, air gap width, magnet center offset, and rotor slot opening size. Although the cogging torque can be reduced by these four methods, the motor performance can also be changed at the same time. Therefore, pay attention to the change of performance while reducing the cogging torque. The results of simulating electromagnetic noise show that, the frequency of motor noise is mainly related to multiply of the number of poles of the motor, the number of slots and the rotation speed of the motor. The frequency of serious noise is the order of 28th, 56th, and 84th related to the motor speed.