PWM-DRIVEN INDUCTION MOTOR CONTROLLER: STATE SPACE APPROACH
By
MUHAMMAD NAJffi BIN MOHD NASRUDDIN
FINAL PROJECT REPORT
Submitted to the Electrical & Electronics Engineering Programme in Partial Fulfillment of the Requirements
for the Degree
Bachelor of Engineering (Hons) (Electrical & Electronics Engineering)
Universiti Teknologi Petronas Bandar Seri Iskandar 31750Tronoh
Perak Darul Ridzuan
©Copyright 2011
by
Muhammad Najib Bin Mohd Nasruddin, 2011
CERTIFICATION OF APPROVAL
PWM-DRIVEN INDUCTION MOTOR CONTROLLER: STATE SPACE APPROACH
Approved:
by
Muhammad Najib Bin Mohd Nasruddin
A project dissertation submitted to the Electrical & Electronics Engineering Programme
Universiti Teknologi PETRONAS in partial fulfilment of the requirement for the
Bachelor of Engineering (Hons) (Electrical & Electronics Engineering)
(Assoc. Prof. Dr. Nordin Saad) trSitiJ~lpervisor
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TRONOH, PERAK
December 2011
CERTIFICATION OF ORIGINALITY
This is to certify that I am responsible for the work submitted in this project, that the original work is my own except as specified in the references and acknowledgements, and that the original work contained herein have not been undertaken or done by unspecified sources or persons.
BIN MOHD NASRUDDIN)
ABSTRACT
In adjustable-speed drive applications, the range of speed and torque achievable is very important. A power electronic converter is needed as an interface between the input AC power and the drive. A controller is needed to make the motor (drive), through the power electronics converter meets the drive requirements. The widely used conventional control that is based on mathematical model of the controlled system is very complex and not easy to be determined since it requires explicit knowledge of the motor and load dynamics.
This final project report is a design and implementation of a state space controller from a for a PWM-driven variable-voltage variable-frequency (VVVF) speed control of an induction motor and the analysis, evaluation and improvement of the control strategies. A simulation model in MA TLAB/Simulink is developed using state space approach to perform verification of the controller. To provide stability in response to sudden changes in reference speed and/or load torque, details study on the pole placement method used in the system will be conducted.
Detailed evaluations of the controller's performance based-on a pre-defined performance indices under several conditions are presented. The findings demonstrate the ability of the control approach to provide a viable control solution in response to the different operating conditions and requirements.
TABLE OF CONTENTS
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CHAPTER!: INTRODUCTION ... 4
1.1. Project Background ... .4
1.2. Problem Statements ... 6
1.3. Objectives and Scope ofStudy ... 6
CHAPTER2: LITEit)lTURE RE~E~ ... 7
2.1 Introduction ... 7
2.2 Induction motor ... 8
2.3 Pulse Width Modulation (PWM) ... 9
2.4 State Space Approach ... 11
2.5 Pole Placement Method ... .12
CHAPTER3: METHODOLOGY ... 13
3.1. Project Work ... .l3 CHAPTER4: RESULT AND DISCUSSION ... 15
4.1 Plant Model of Simulink diagram ... .15
4.2 System poles characteristics without controller ... 17
4.3 State feedback controller poles characteristics ... 19
CHAPTERS: CONCLUSION AND RECOMMENDATION ... .32
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LIST OF FIGURES
Figure 2.1: Basic PWM model.. ... 9
Figure 2.2: PWM signals ... 10
Figure 4.1: Simulink diagram of the G1 transfer function in state space without controller ... .15
Figure 4.2: The output response of the state space system given a step input of 600rpm is applied ... 16
Figure 4.3: Poles moving in vertical direction ... .17
Figure 4.4: Poles moving in horizontal direction ... 17
Figure 4.5: Poles moving in constant radial line direction ... 18
Figure 4.6: Simulink diagram of the G1 plant in state space with state feedback controller ... 19
Figure 4. 7: System response for vertical moving direction poles ... 23
Figure 4.8: System response for horizontal direction poles ... 26
Figure 4.9: System response for constant radial line direction poles ... 29
Figure 4.10: System response using the best pole placement ... .30
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