MD Sabbir Ahmed

Speed Control of Sensorless Brushless DC Motor MD Sabbir Ahmed

This book is all about running a brushless DC motor using a sensorless technique. The target of the work was to make a very simple operating method for a brushless motor and formulate a speed control mechanism. Initially the work was started with both considering back-EMF and without considering back-EMF. Because of more complexity in the back-EMF sensing method, and as our intention was to make a simpler and cost effective operation, so finally we assembled our project the without back-EMF sensing. Even though being a simple and inexpensive machine, the performance was quite good. However adding back-EMF sensing in this machine can give it more dependability. TABLE OF CONTENTS: DECLARATIONIAPPROVALIIACKNOWLEDGEMENTIIILIST OF FIGURESVIIABSTRACTIXCHAPTER 1INTRODUCTION101.1. Introduction101.2. Historical Background101.3. Advantage over Traditional Method111.4. Objective of this Work121.4.1. Primary objectives121.4.2. Secondary Objectives121.5. Introduction to this Thesis12CHAPTER 2BRUSHLESS DC MOTOR142.1. Introduction142.2. Comparison of Brushless motor with brushed motors152.3. Structure of a BLDC152.3.1. Stator162.3.2. Rotor172.4. Operating Principle182.4.1. Sensored Commutation192.4.2. Conventional Control Method Using Hall-effect Sensors202.4.3. Sensorless Control222.5. Applications232.6. Summary24CHAPTER 3MOTOR DRIVE SYSTEMS253.1. Introduction253.2. Components of Drive Electronics253.3. Inverter263.3.1. Three-Phase Inverter263.3.1.1.120-Degree Conduction273.3.1.2.180-Degree Conduction293.4. Speed Control Techniques303.4.1. Open Loop Speed Control313.4.2. Closed Loop Speed Control313.4.2.1. Proportional-Integral (PI) Controller323.5. PWM based Methods333.5.1. Conventional 120° PWM technique333.5.2. PWM Duty Cycle Calculation333.6. Summary34CHAPTER 4SIMULATION354.1. Introduction354.2. Simulation354.2.1. Simulating Three-Phase Inverter364.2.2. Simulating Controller Unit384.3. Simulation Results394.3.1. Speed Control404.4. Summary40CHAPTER 5HARDWARE IMPLEMENTATION415.1. Introduction415.2. Equipments and Components425.3. Power Supply Unit435.4. Microcontroller Unit445.5. Motor Drive Unit455.6. Performance of the System465.7. Summary47CHAPTER 6DISCUSSIONS AND CONCLUSIONS486.1. Discussions486.2. Suggestion for future Work496.2.1. Limitations496.2.2. Future Scope496.3. Conclusions50REFERENCES51APPENDIX A53SPEED CONTROL FLOWCHART53APPENDIX B54MICROCONTROLLER CODES54APPENDIX C55ATMEGA32 (MICROCONTROLLER)556.3.1. Pin Descriptions556.3.2. Block Diagram586.3.3. Electrical Characteristics59APPENDIX D60L298 (DUAL FULL-BRIDGE DRIVER)606.3.4. Pin Configurations606.3.5. Maximum Ratings61