Yetmişli yılların başında geliştirilen dolaylı Alan Oryantasyonlu Kontrol (AOK) metodu, AC asenk-ron motorların yüksek başarım gerektiren değişken hız uygulamalarında kullanılmasını sağlamıştır. Diğer taraftan, yüksek mertebeli çok değişkenli doğrusal olmayan matematik modellerle temsil edi-lebilen AC asenkron motorlar, sahip oldukları karmaşık dinamiğe ilave olarak, çalışmaları sırasın-da bilinmeyen bozuculara (yük momenti) ve rotor ve startor direnci gibi parametrelerinin değişim-lerine maruz kalırlar. Halihazırda yapısal basitliği ve kullanımının yaygınlığı nedeniyle asenkron motorların hız kontrolünde PID kontrol yaygın olarak kullanılmaktadır. Bu yaygın kullanımına rağmen PID kontrolün birçok dezavantajları söz konusudur. En önemli dezavantajlarından biri her çalışma şartında istenen kapalı çevrim performans taleplerini karşılayabilecek kazanç parametrele-rinin ayarlanması işidir. Tipik bir AOK şemasında, aynı anda ayar edilmesi gereken üç PID çevrimi vardır. Performans talepleri genellikle birbirleriyle çeliştiğinden, her çevrim için en uygun kazanç-ları ayarlama işi oldukça uzun zaman ve aynı zamanda deneyim gerektirir. Ayarlanmasının nispe-ten kolay olduğu Model Öngörülü Kontrol, son yıllarda doğrusal ve doğrusal olmayan sistemlerin kontrolünde oldukça yaygın olarak kullanılan önemli metotlardan biri olmuştur. Bu çalışmada PID kontrolün dezavantajlarını ortadan kaldırmak ve AC asenkron motorun bozucu reddetme cevabı ve kumanda izleme performansını geliştirmek üzere bir model öngörülü kontrol tekniği geliştirilmiştir. Durum uzayı formunda geliştirilen teknikte, AC motorun referans modeli olarak dolaylı vektör kontrolü prensibinden faydalanılarak türetilen doğrusal bir model temel alınmıştır. Önerilen tekni-ğin gürbüzlüğünü ve izleme performansını ortaya çıkarmak için değişik benzetim senaryoları oluş-turulmuştur.

The DC motors have been the most popular in the motion control applications due to their flexibility in the control of torque and speed using field flux and armature current. However, DC motors posses in-herent problems due to the existence of the commu-tators and brushes. The commutators require peri-odical maintenance and also due to the sparks cre-ated by them DC motors cannot be used in explosive or corrosive environments. On the other hand, since the AC current has become an economical form of power supply for operating industrial machinery, much attention has been given to the development of AC motors. Some advantages of AC induction motor are: Cost effectiveness, high reliability, no commu-tator and brush mechanism, no electric arcing, etc. The only drawback holding these motors behind from more common use was the difficulty of variable speed control. However, with the invention of Field Orientation Control (FOC), the use of AC induction motor has become more and more abundant. The FOC technique decouples the flux and torque con-trol, in an AC motor, thus makes high performance induction motor drive theoretically feasible. Due to the relatively simple formulation, most of the industrial drivers utilize indirect FOC technique. Currently, PID controller structure is widely used in the indirect FOC based driver, mainly due to its simplicity in structure, and familiarity to most field operators. However, despite its widespread use, PID controller does have a number of limitations. One of the main drawbacks of PID controller is the task of tuning gains to achieve a set of desired closed-loop performance in every condition. It is very difficult to suit a wide range of working conditions with only a set of fixed gains. Also, despite its simplicity, the PID controller cannot always effectively control sys-tems with changing parameters or strong non-linearities and they may need frequent on-line retun-ing. In a typical PID based indirect FOC scheme, there are three PID loops that should be tuned properly. Since performance specifications general-ly conflict with each other, the task of tuning gains to meet several closed-loop performance specifica-tions requires considerable time and experience. These drawbacks of the PID based controllers imply a need for a reliable control method designed sys-tematically to meet all performance specifications. This, in fact, was the one of the main objectives of this study. MPC is one of the most important methods for both linear and nonlinear systems including unstable sys-tems. Also, the concept predictive control is not re-stricted to single input single output (SISO) systems; it can easily be applied to multi input multi output systems. One of the attractive features of predictive controller is that they are relatively easy to tune. On the other hand, since predictive controller is evalu-ated in the class of model based controller design method, a model that adequately represents the plant must be available. If a plant can be represent-ed with a linear model, the calculation of the control action would be relatively fast, thus suitable for in-dustrial FOC drivers. There is therefore a strong motivation for obtaining the linear model of AC in-duction motor. AC IM is essentially a high order multivariable non-linear system. In this work, utilizing the principle of indirect FOC and applying the input-output lineari-zation technique, a reduced order linear model of AC IM was developed. Similar linear model based model predictive control study in the literature (Kutasi et al., 2008) did not consider the steady-state error caused by model un-certainties, viscous friction, unknown disturbances, etc. However, the induction motor cannot generate any torque at zero speed if steady-state error exists. In this study, to remove the steady-state error, an artificial state as an integrator of the electrome-chanical torque error has been added. The new state greatly improved the performance of the developed model based controllers. One of the main contributions of this work was to develop a model predictive control technique based on the indirect FOC to improve the command track-ing performance and the disturbance rejection re-sponse of the AC induction motor. Several simula-tions were performed to illustrate the tracking per-formance and robustness of the proposed technique. It was seen that the MPC based controller could im-prove the performance of classical indirect FOC drives especially in the presence of disturbance such as external load torque and changes in the rotor re-sistance.