電動機車新型低稀土單磁性永磁馬達開發

Abstract

本研究專注於兩輪機車載具所應用的單磁極永磁馬達（Consequent-pole Permanent Magnet Motor, CPM），提出一套系統性的優化設計流程。研究中參考了市面上睿能公司所推出的第二代6 kW內藏式永磁同步馬達（Interior Permanent Magnet Motor, IPM），其最大運轉轉速可達9000 rpm。在馬達設計方面，有鑑於稀土磁鐵材料供應源短缺與電動載具市場對稀土磁鐵需求的顯著上升，本研究的目標主要聚焦於在保持相同直流母線電壓和相電流限制的情況下，於降低稀土磁鐵使用量的同時，對力矩、功率和效率曲線進行改進，以降低馬達製作材料的成本與對稀土磁鐵的依賴。 在單極轉子的設計中，由於磁鐵擺放位置與方向的不對稱性，磁鐵所提供的磁通密度分布與馬達運轉時的反電動勢(Back Electromotive Force, Back EMF)相較於傳統IPM馬達在一個電氣周期內的波型較不理想，並且可能會出現一個周期內波型不對稱的情況，導致單極馬達在未加負載電流時的齒卡力矩（Cogging Torque）和負載後輸出的力矩其漣波（Torque Ripple）峰值會有明顯的增加。為解決這個問題，本研究將通過馬達肋部的縮減以及優化轉子磁鐵的擺放位置，以彌補稀土磁鐵減少所帶來的力矩和功率損失，同時降低由不對稱磁鐵引起的力矩漣波。 在設計階段，本研究運用有限元素法（Finite Element Analysis, FEA）軟體Ansys Maxwell進行穩態性能分析。在馬達暫態響應方面，則採用MATLAB & Simulink軟體進行控制演算法和逆變器的模擬，最後進行模擬結果與實驗數據的對比與分析。

This research focuses on proposing a systematic optimization design process for the application of a single-pole Consequent-pole Permanent Magnet Motor (CPM) in two-wheeled motorcycles. We refer to Gogoro's commercially available second generation 6 kW Interior Permanent Magnet Motor (IPM) with a maximum operating speed of up to 9000 rpm. The primary objective is to reduce the use of rare earth magnets while improving torque, power and efficiency curves under the same voltage and current performance conditions. Although consequent pole motors can improve magnetic flux density by reducing the effective air gap, the asymmetry of the magnets in the rotor significantly increases cogging torque and torque ripple after loading. To address this issue, the study focuses on reducing motor cogging by modifying the motor ribs and optimizing the placement of the rotor magnets to compensate for torque and power losses due to reduced rare earth magnets. At the same time, efforts are being made to minimize torque ripple caused by asymmetric magnets, resulting in the development of a motor with reduced rare earth magnet usage. During the design phase, Finite Element Analysis (FEA) is used for steady-state performance analysis. For transient motor response, MATLAB & Simulink software is used to simulate control algorithms and inverters, with subsequent comparison between simulation and experimental results.