以印刷電路板實現軸向式馬達定子繞組於電動自行車之應用

Abstract

本論文針對應用於電動自行車且採用無鐵心(coreless)設計之軸向式馬達(axial-flux motor)進行分析與探討，因其定子繞組並非固定於矽鋼片上，而是以特殊樹脂材料加以固定線圈，故此類馬達定子繞組在製作上須賴以手工繞製而使其無法進行大量生產及產生品質不一等缺點。為改善上述之缺點，本論文利用印刷電路板(printed circuit board, PCB)取代既有以銅線纏繞之軸向式馬達定子繞組，針對在相同轉子磁通量分布下提出印刷電路板之定子繞組設計方法，包括印刷電路板之設計方法、測試平台的建立以及樣品之實測結果分析。首先以轉子永久磁鐵排列與體積的限制為依據，建立一印刷電路板定子繞組佈線圖，並針對其功率密度(power density)、轉矩常數、電阻與電感等之分析作為設計考量，藉以選擇一較佳的定子繞組佈線做為樣品進行後續測試。在馬達測試方面，本論文針對此馬達分兩部份進行單片印刷電路板定子繞組測試，其一為馬達操作於發電機模式時，量測其所感應之反抗電動勢，藉由三相反抗電動勢波形估測其反抗電動勢常數、總諧波失真(total harmonic distortion, THD)、磁通量分布及參數鑑別等，可推論所設計之馬達其反抗電動勢近似正弦波，總諧波失真約為7%。其次則為馬達操作於電動機模式時，針對其單片定子繞組進行驅動控制測試，其利用線性型霍爾感測器訊號做為轉子位置之參考，以正弦脈波寬度調變(sinusoidal PWM, SPWM)進行驅動控制之模擬與實驗分析。測試結果得以驗證軸向式馬達使用印刷電路板定子繞組的可行性與效能。

This thesis presents an analysis and discussion of the axial-flux motor used on electrical-bike and adopted a coreless design. Therefore, the stator winding fix by a special resin instead of traditional silicon steel. It causes the stator winding can’t be mass produced and have quality variations. In order to improve this problem, this thesis presents a design of the axial-flux motor used on electrical-bike with printed circuit board (PCB) stator winding to instead of copper wire in the same rotor flux distribution, including PCB stator winding design method, test experiment prototype setup and analysis of PCB stator winding prototype test results. By regarding the analysis of shape and position of permanent magnets, power density, torque constant and basic parameters to develop a better PCB stator winding layout. In motor test, the generation mode, measure the tri-phase back-emf to calculate and estimate the back-emf constant, total harmonic distortion (THD), flux distribution and motor *parameters. The results infer that the back-emf is similar to a sine wave and THD is about 7%. Then setup a control system with linear hall-effect sensors and sinusoidal PWM control strategy to drive this motor with a single PCB stator winding. By simulation and experiment to test and analyze the current response, motor performance, skin-effect and temperature, etc. The test and experiment results verifies the feasibility and performance of the axial-flux motor with PCB stator winding.