Field-Oriented Induction Machine (FOIM) Assignment Solution

INTRODUCTION

1.1 Introduction
In recent years, field-oriented induction machine (FOIM) drives have been increasingly utilized in motion control applications due to easy implementation and low cost. Besides, they have the advantage of decoupling the torque and flux control, which makes high servo quality achievable. However, the decoupling control feature can be adversely affected by load disturbances and parameter variations in the motor so that the variable-speed tracking performance of an IM is degraded. In general, both conventional PI and PID controllers have the difficulty in making the motor closely follow a reference speed trajectory under torque disturbances. In this regard, an effective and robust speed controller design is needed.

Fuzzy-logic-based intelligent controllers have been proposed for speed control of FOIM drives. Those intelligent controllers are associated with adaptive gains due to fuzzy inference and knowledge base. As a result, they can improve torque disturbance rejections in comparison with best trial-and-error PI or PID controllers. Nonetheless, no performance advantages of intelligent controllers in combination with a PI or PID controller are investigated.

1.2 Problem Formulation
Motivated by the successful development and application, we propose a hybrid PID+ fuzzy controller consisting of a PID controller and a fuzzy logic controller (FLC) in a serial arrangement for speed control of FOIM drives, more specifically; direct field-oriented IM (DFOIM) drives. The Ziegler-Nichols (Z-N)) method in is adopted for designing a PID controller (denoted as ―the Z-N PID‖) because its design rule is simple and systematic. We next design a FLC carrying out fuzzy tuning of the output of the Z-N PID controller to issue adequate torque commands.

Based on a simulation model of the DFOIM drives incorporating the proposed controller, experiments are set up in a Mat lab /Simulink environment and implemented in real time using the MRC-6810 analog-to-digital (AD)/ digital-to-analog (DA) servo control card together with a DSP electronic controller. The results show that the incorporation of the proposed controller into the DFOIM drives can yield superior and robust variable-speed tracking performance.

1.3 Objective of Thesis
The main objective of this project is to control the speed of the induction motor using a hybrid PID and fuzzy logic controller and to also improve the stability, transient response and load disturbance rejection of speed control of an Induction motor.

1.4 ORGANISATION OF THESIS
Chapter 1: Discusses about the introduction to the project, challenges involved and the main objective of the work.
Chapter 2: Explains the study of all the existing literature on the topic and its influence on the design process.
Chapter 3: Discusses the theoretical analysis of the project, Design calculations and final design of the Simulink model.
Chapter 4 : Discusses about the implementation of the Simulink to control the speed of the induction motor using fuzzy logic
Chapter 5: The final output of the project explained and the results are discussed.
Chapter 6: The conclusion of the project is stated.

LITERATURE SURVEY

The classical or conventional type of control is used in most of the electrical motor drives. It requires mathematical model to control the system. When there are system parametric variations, the behavior of the system is unsatisfactory and it deviates from the desired performance.

Pillay and Levin developed mathematical models like the dq model and the abc models incorporating the various forms of impedance and/or voltage unbalances and designed controllers to control the various parameters of the IMs using the d–q method and the abc method.

The new minimum-time, minimum-loss speed control algorithms are developed for IM to obtain better performance, efficiency, under FOC with practical constraints on voltage and current.

A novel control technique for controlling some of the parameters of IM using the SVPWM method is presented.

Also an excellent 3Φ bridge inverter, which was used to apply a balanced 3Ф voltage to the SCIM, was developed.

Maamoun presented an SVPWM technique based inverter for v/f control method, and it was used for open loop speed control of IM. Ben-Brahim proposed a modified ̳v/f‘ method of developing a controller for high-rating IMs in his paper which yielded excellent results.