感應馬達弱磁控制設計與實證

Design and Verification of a Field Weakening Control Scheme for Induction Machines

陳家宏(Chia-Hung Chen 陳家宏)

指導教授 ： 楊勝明

國立臺北科技大學/電資學院/電機工程系研究所/碩士(2009年)

摘要

利用轉子磁場導向來驅動感應馬達在工業界早已廣泛的使用，磁場導向主要是仿效直流馬達的運轉方式，將激磁電流與轉矩電流分開控制。轉子磁場導向的感應馬達在額定轉速內使用固定之激磁，此區域馬達可以以定轉矩方式運轉。在實現高於額定轉速運轉時，轉子磁場須隨轉速下降以限制感應馬達的反電動勢，避免馬達電壓太過接近於變頻器直流匯流排上的電壓，此方法通常稱為弱磁控制。由於轉子磁場減弱相當於轉矩常數降低，因此馬達最大的輸出轉矩會與轉速成反比，此時馬達只能維持在定功率運轉。
本文的主要目的在探討感應馬達在高速時之弱磁控制策略、控制器設計流程及驅動系統，利用數位訊號處理及週邊硬體電路，使用具有電壓控制迴路之弱磁控制方法。此控制方法測量馬達電壓與變頻器直流匯流排上的電壓進行比較，比較結果產生適當的磁通電流命令，利用簡單的閉迴路控制策略，即可達到高速運轉。實驗結果證實此控制策略在無載實驗時達到感應馬達額定轉速3.5倍運轉，連接動力計時轉速可達到基本轉速的2倍及加載1牛頓-米的實驗測試，並獲得良好的暫態響應。

關鍵字

感應馬達 ； 磁場導向 ； 弱磁控制

並列摘要

Rotor flux filed orientation is commonly used in industry for induction motor drives. The principle of this control scheme is to imitate brushed dc motor drive operation, where the field and torque controlling currents are separately controlled. Below the base speed, magnetic field of a rotor flux field oriented induction motor drive is generally fixed. For high speed operations, however, magnetic field must decrease with speed in order to keep motor back-emf from too close to the supply voltage. This method is generally called field weakening control. Because the field is decreased with the field weakening control, the motor can only operate with constant power output.
The purpose of this thesis is to develop a field weakening control scheme for induction motor drives. The proposed scheme is consist of a voltage control loop and implemented using digital signal processors. The controller uses the field current to regulate the error between motor terminal voltage and inverter dc bus voltage. High speed operations are achieved with a simple closed-loop control strategy. The experimental results shown that three and half times the base speed can be achieved for no load operations, and two times the base speed can be achieved with 1 N-m load. Both operations have good dynamic responses.

並列關鍵字

Induction Motor ； Flux Filed Orientation ； Field Weakening

參考文獻

[36] 李韋瑩, “感應馬達之電氣參數自動辨識研究,” 淡江大學機械與機電工程學系碩士論文, 2004.

[2] M. Zeraoulia et al., “Electric motor drive selection issues for HEV propulsion systems: a comparative study,” in Proc. IEEE-VPPC, Sep. 2005, pp. 280-286.

[4] K. Hasse, “Zur Dynamik Drehzahlgeregelter Antriebe Mit Stromrichterg - espeisten Asynchron - Kurzschlublaufermaschinen,” Ph. D Dissertation, Techn. Hochschule Darmstadt, July 17, 1969.

[7] B. K. Bose, “Power electronics and AC drives,” Prentice-Hall, Englewood Cliffs, NJ, USA, 1986.

[8] A. M. Trzynadlowski, “The field orientation principle in control of induction motors,” Kluwer Academic Publishers, Netherland, 1992.