永磁馬達之傳統直接轉矩控制(Conventional Direct Torque Control, DTC)，控制架構簡單、轉矩響應快速，在負載快速變動的應用場域極具優勢，但也由於其採用簡單的磁滯查表法，對轉矩與定子磁交鏈都不是精準控制，導致轉矩漣波過大，也造成切換不定頻，產生的電磁干擾(Electromagnetic Interference, EMI)較難處理。於是本文將模型預測控制法(Model Predictive Control, MPC)引入直接轉矩控制之中，以馬達在alpha eta靜止兩相座標系下的數學模型，預測施加各基本電壓向量控制馬達，產生之未來時刻相應轉矩與磁交鏈，利用目標函數取代傳統直接轉矩控制的磁滯查表，準確決定合適的電壓向量輸出，實際控制馬達運轉，並加入脈波寬度調變，控制電壓向量作用的時間長度，使其趨近定頻切換，更大幅下修轉矩漣波。
由實驗結果證明本文策略確實提高轉矩精度，且轉矩響應速度高於磁場導向向量控制(Field Oriented Control, FOC)，並降低平均開關切換頻率，減少功率電晶體的切換損失。

This dissertation presents an improved model predictive control (MPC) strategy to reduce the torque ripple and commutation frequency in conventional direct torque control (DTC) of the permanent magnet synchronous motor (PMSM). Nowadays, DTC has been widely used in industrial applications thanks to its simple structure and high dynamic performances. However, hysteresis controllers cause high torque ripple and variable switching frequency. In this novel method, hysteresis controllers and the switching table are replaced with a model predictive controller base online optimization for the selection of voltage space vector among the possible ones. Furthermore, a pre-selective process is designed to filter out the inappropriate voltage vectors to reduce the computational burden caused by the eight basic voltage space vectors. Then apply duty ratio modulation to determine the operating time of the selected voltage vector and zero voltage vector in one sample period for torque ripple reduction. By implementing the proposed DTC, torque ripple is reduced and the approximated switching frequency can be minimized to retain the advantages of a conventional DTC; meanwhile, the torque response is still quick. Both simulation and experimental results exhibit the effectiveness of this proposed approach.

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