Abstract
本文旨在設計一高性能感應馬達伺服驅動系統，且其性能無論在速度及位置控制上均不易受參數變化及外來干擾之影響。縱然磁場導向技術之利用可使感應馬達伺服驅動系統之控制特性相似於他激式直流馬達，但其性能容易受馬達參數變化之影響。為了使驅動系統具有良好之控制特性，需要更複雜的控制法則，也需要功能更強之處理器來執行這些法則。由於數位信號處理器的發展，使得複雜控制之及時(real-time) 執行變得更為容易。本論文即在介紹一以數位信號處理器為主的間接磁場導向感應馬達伺服驅動系統及其控制法則。系統中利用數位信號處理器與個人電腦相結合，提供處理複雜運算法則的良好環境。在高性能控制器設計之方面， 本文首先發展一套雙可調度 (two-degree-of-freedom) 控制器之系統化設計步驟，以使驅動系統在命令追隨及負載調節方面能同時具有良好的控制特性。接著設計一個具有直接消去不明系統動態(uncertainties) 的簡單強健控制器 (robust controller)，使驅動系統在參數變化及外在干擾下仍能保持良好之控制特性，上述控制器亦考慮了控制力與控制特性間之協調。由於延遲時間之存在會影響閉迴路驅動系統的穩定度及控制特性， 因此設計一個延遲時間補償器 (dead- time compensator) 以克服上述問題。將延遲時間補償器與前述之強健雙可調度控制器相結合以改善驅動系統之操作特性，並且利用在參數平面上之穩定度分析來設計此系統。文中並利用模擬及實作之結果來驗証上述控制器之功能。本文之內容如下：首先在第二章中設計及製作一套間接磁場導向感應馬達伺服驅動系統，並詳述了磁場導向的原理，感應馬達之物理模式 (physical modelling) 及以數位信號處理器為主的控制電腦架構。另外也介紹了在位置控制中用來產生負載干擾之機構。接著在第三章中利用隨機估測 (stochasticmodelling ) 技術來估測速度迴路之動態模式。由於隨機估測方法較不適用於轉子靜止之狀態，故利用步級響應及曲線配合(curve fitting ) 之技術找出位置迴路之動態模式。第四章敘述了雙可調度控制器之系統化設計步驟，使驅動系統同時在命令追隨及負載調節等特性上具有良好之控制特性。為使系統之控制特性不受參數變化及外來干擾之影響，第五章提出一個簡單的強健控制器。接著在第六章中說明了延遲時間補償器的原理及如何與強健雙可調度控制器相結合，以減低延遲時間對系統控制特性之不良影響。最後第七章為結論。Even though the field-oriented induction motor drive can beoperated as a separately excited DC motor, itsperformance is much affected by the variations of motorparameters. Therefore, more sophisticated control techniquesare required to achieve better control performances, andmore powerful processors are also needed to implement thesecontrol algorithms. Recently, due to the development ofDSPs, the realization of complex real-time control tech-niques becomes easier. A DSP-based indirect field-orientedinduction motor servo drive and its feedback control arepresented in this dissertation. The DSP with suitableinterfacing to a personal computer provides an environmentfor realizing complex control algorithms. As for thedevelopment of high performance controllers, in order to letthe drive have good command tracking and load regulatingdynamic responses, the two-degree-of-freedom speed andposition controllers and their systematic design proceduresare introduced first. Then a simple robust controllerbased on direct cancellation of uncertainties is proposedsuch that the desired drive control performances can bepreserved under parameter variations and externaldisturbances. In the proposed robust controller, theperformances and the control effort can be compromised. Theexistence of system dead-time may greatly affect thestability and performances of the closed-loop controlleddrive system. A dead-time compensator is then proposed tosolve this problem. The proposed dead-time compensator isdesigned based on the stability analysis made on theparameter plane. The effectiveness of the proposedcontroller and the performance of the motor drive aredemonstrated by some simulation and experimental results.