感應馬達高速運轉之弱磁控制策略

Abstract

本論文針對感應馬達應用編碼器角度感測器的高速運轉力矩控制，提出定功率區(Constant power region)的新型控制方法，藉此提高感應馬達的可控轉速，同時維持有效的力矩輸出，其應用是在電動載具包含電動車、電動機車或者自動搬運車等，確保載具使用之感應馬達的速度表現能夠符合各類使用需求。 本論文所提出的新複合型弱磁控制策略是根據既有的一般複合型弱磁控制架構進行改良，整合回授型架構內部的電壓控制器與前饋型架構的直接輸入電流命令兩種架構，使新複合型弱磁控制策略能夠有效適應不同的初始磁通分量電流以及不同電壓命令，有效減少力矩與弱磁控制模式切換的暫態響應，同時，確保系統能夠在不同力矩條件下進入弱磁控制，滿足定功率區的定義。 最後本論文針對一顆6kW的感應馬達進行實驗測試，根據實驗結果，新複合型弱磁控制策略能夠達成定功率控制，正確減少磁通分量電流，抑制反電動勢，拓展速度可控區間，由原先5300RPM馬達即將失控的情況，改善至10000RPM都能穩定控制，並且比較一般複合型弱磁控制控制模式，在控制模式切換過程的電壓暫態反應，新複合型弱磁控制策略不會發生明顯的電壓暫態反應，更不會出現電壓失控的情況。

This thesis proposes a novel constant power control methodology for high speed torque control of induction motor. The objective is to enhance the motor controllable speed while ensuring effective torque output. This approach is intended for application in electric vehicles, including cars, motorcycles, or automated guided vehicles, to guarantee that the motor speed performance meets diverse usage demands. The proposed control strategy enhances the existing hybrid field weakening control framework. It integrates the voltage controller within the feedback framework and the direct input current command within the feedforward framework. The proposed integrated field weakening control can meet the constant power region definition. It also adapts to different initial magnetic flux component currents and voltage commands. Moreover, it can reduce the transient response during constant torque and constant power control mode transitions, while ensuring the system can enter field weakening control under various torque conditions. Finally, a 6-kW induction motor is used for experimental verification. According to experimental results, the proposed hybrid field weakening control achieves the constant power control by accurately reducing the magnetic flux component current and suppressing the back electromotive force. It extends the controllable speed range from 5300 RPM to 10000 RPM. A comparison of voltage transient response during control mode switching is performed between the general hybrid field weakening control and the proposed control strategy. It concluded that the proposed field weakening control minimize the voltage transient response with improved voltage control stability.