Direct Power and Torque Control of AC/DC/AC Converter-Fed ...

Contents
Page
1. Introduction............................................................................................................ 1
1.1. AC/DC/AC Converters ..................................................................................... 1
2. Voltage Source Converters – VSC...................................................................... 11
2.1. Introduction..................................................................................................... 11
2.2. Space Vector Based Description of VSC........................................................ 11
2.3. Operation of Voltage Source Converter – VSC.............................................. 12
2.4. Mathematical Model of the VSI - Fed Induction Motor (IM) ........................ 14
2.4.1. IM Mathematical Model in Rotating Coordinate System with Arbitrary
Angular Speed.................................................................................................... 16
2.4.2. IM Model in Stationary αβ Coordinates ................................................ 16
2.4.3. IM Model in Synchronous Rotating dq Coordinates - RFOC ................ 18
2.4.4. IM Model in Synchronous Rotating xy Coordinates - SFOC................. 19
2.5. Operation of Voltage Source Rectifier – VSR................................................ 22
2.5.1. Operation Limits of the Voltage Source Rectifier – VSR ....................... 24
2.5.2. VSR Model in Three-Phase ABC Coordinates........................................ 27
2.5.3. VSR Model in Stationary αβ Coordinates............................................... 29
2.5.4. VSR Model in Synchronously Rotating xy Coordinates ......................... 30
2.6. Summary ......................................................................................................... 32
3. Vector Control Methods of AC/DC/AC Converter-Fed Induction Motor
Drives – A Review .................................................................................................... 33
3.1. Introduction..................................................................................................... 33
3.2. Control Methods of VSI-Fed Induction Motor ............................................... 34
3.2.1. Field Oriented Control – FOC ................................................................. 34
3.2.2. Direct Torque Control – DTC.................................................................. 38
3.2.3. Direct Torque Control with Space Vector Modulation – DTC-SVM...... 43
3.3. Control Methods of VSR ................................................................................ 45
3.3.1. Virtual Flux Oriented Control – V-FOC.................................................. 45
3.3.1.1. Line Current Controllers ....................................................................... 47
3.3.2. VF based Direct Power Control – VF-DPC............................................. 52
3.3.3. Direct Power Control with Space Vector Modulator – DPC-SVM ......... 57
3.3.3.1. Line Power Controllers ......................................................................... 57
3.3.3.2. DC-link Voltage Controller .................................................................. 65
3.4. Conclusion ...................................................................................................... 68
4. Direct Power and Torque Control with Space Vector Modulation – DPTC-
SVM........................................................................................................................... 69
4.1. Introduction..................................................................................................... 69
4.2. Model of the AC/DC/AC Converter-Fed Induction Motor Drive with Active
power feedforward ................................................................................................. 69
4.2.1. Analysis of the Power Response Time Constant ..................................... 71