以DSP為基礎發展永磁同步馬達使用線性型霍爾感測器與無感測控制方法

Abstract

本論文利用數位訊號處理器發展弦波型永磁同步馬達的控制方法，包括使用線性型霍爾感測器之伺服控制架構，以及以定子磁通估測為基礎之無感測速度控制。首先利用線性型霍爾感測器訊號做為轉子位置之參考，達到磁場導向控制的目的，不需透過靜止三軸與同步旋轉二軸間的座標轉換，而能在三軸靜止座標直接產生各相電流命令。由轉子位置資訊可計算轉速，進而達到速度控制與定位控制之目的。另一方面，無感測演算法以磁通鏈增量與正規化的反抗電動勢函數估測轉子角度變化量。此無感測演算法對於因數位化處理的量化誤差，以及回授訊號的雜訊所造的轉子角度估測誤差具有內迴路的自動修正機制。數學分析與電腦模擬驗證了此方法的強健性。然而，馬達參數的變異，以及回授訊號的不準確仍會導致估測誤差，對此本論文亦呈現分析與模擬之結果。根據這個以定子磁通估測為基礎的方法，本論文提出一種新型的演算法，此新型演算法加入了估測反抗電動勢峰值為另一個參數，藉由調整其比重能得到較原演算法為佳的估測性能。此外，為了提升穩態時馬達的運轉效率，本論文提出一個參數調整機制，刻意的使估測結果產生誤差，使各相電流能與反抗電動勢同相。實驗結果驗證了使用線性型霍爾感測器以及無感測控制方法的可行性與性能。

This thesis presents the development of control methods based on a digital signal processor (DSP) for permanent magnet synchronous motors (PMSMs). Two methodologies are presented: 1) a servo control architecture employing linear Hall effect sensors, and 2) a sensorless speed control scheme with a flux-based rotor position estimation algorithm. By using linear Hall effect sensors, the rotor position information can be obtained, and flux-oriented control (FOC) is achieved by generating current references in the three-phase stationary frame without the stationary-to-rotating reference frame transformation and its inverse. Also, the rotor speed can be calculated, and then speed control and position control are carried out. On the other hand, the sensorless algorithm uses the incremental values of flux linkage and the normalized back-EMF functions to estimate incremental rotor position. An internal closed-loop correction mechanism within this algorithm can correct rotor position estimation drift, which could due to quatization error of digital processing or measurement noise. Mathematical analyses and numerical simulations demonstrate robustness of this sensorless algorithm. However, motor parameter variations and measurement inaccuracies still introduce rotor position estimation error. Sensitivity analyses to motor parameters and measured signals are also presented. According to this flux-based sensorless approach, a new algorithm is proposed. The estimated back-EMF peak value is involved in the new algorithm as an additional parameter. By tuning the weighting of the new parameter, better performance than the original algorithm’s can be obtained. This thesis proposes another approach, which makes the phase current be inphase with each phase back-EMF respectively by tuning a parameter in the new sensorless algorithm at the steady state to intentionally produce rotor position estimation error. An experimental platform has been constructed and results are given for verification.