Direct torque control

Abstract: New quick-response and high-efficiency control of an induction motor, which is quite different from that of the field-oriented control is proposed. The most obvious differences between the two are as follows. 1) The proposed scheme is based on limit cycle control of both flux and torque using optimum PWM output voltage; a switching table is employed for selecting the optimum inverter output voltage vectors so as to attain as fast a torque response, as low an inverter switching frequency, and as low harmonic losses as possible. 2) The efficiency optimization in the steady-state operation is also considered; it can be achieved by controlling the amplitude of the flux in accordance with the torque command. To verify the feasibility of this scheme, experimentation, simulation, and comparison with field-oriented control are carried out. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme.

Abstract: 1. Elementary Principles of Mechanics.- 1.1 Newtons Law.- 1.2 Moment of Inertia.- 1.3 Effect of Gearing.- 1.4 Power and Energy.- 1.5 Experimental Determination of Inertia.- 2. Dynamics of a Mechanical Drive.- 2.1 Equations Describing the Motion of a Drive with Lumped Inertia.- 2.2 Two Axes Drive in Polar Coordinates.- 2.3 Steady State Characteristics of Motors and Loads.- 2.4 Stable and Unstable Operating Points.- 3. Integration of the Simplified Equation of Motion.- 3.1 Solution of the Linearised Equation.- 3.1.1 Start of a Motor with Shunt-type Characteristic at No-load.- 3.1.2 Starting the Motor with a Load Torque Proportional to Speed.- 3.1.3 Loading Transient of the Motor Initially Running at No-load Speed.- 3.1.4 Starting of a DC Motor by Sequentially Short-circuiting Starting Resistors.- 3.2 Analytical Solution of Nonlinear Differential Equation.- 3.3 Numerical and Graphical Integration.- 4. Thermal Effects in Electrical Machines.- 4.1 Power Losses and Temperature Restrictions.- 4.2 Heating of a Homogeneous Body.- 4.3 Different Modes of Operation.- 4.3.1 Continuous Duty.- 4.3.2 Short Time Intermittent Duty.- 4.3.3 Periodic intermittent duty.- 5. Separately Excited DC Machine.- 5.1 Introduction.- 5.2 Mathematical Model of the DC Machine.- 5.3 Steady State Characteristics with Armature and Field Control.- 5.3.1 Armature Control.- 5.3.2 Field Control.- 5.3.3 Combined Armature and Field Control.- 5.4 Dynamic Behaviour of DC Motor with Constant Flux.- 6. DC Motor with Series Field Winding.- 6.1 Block Diagram of a Series-wound Motor.- 6.2 Steady State Characteristics.- 7. Control of a Separately Excited DC Machine.- 7.1 Introduction.- 7.2 Cascade Control of DC Motor in the Armature Control Region.- 7.3 Cascade Control of DC Motor in the Field-weakening Region.- 7.4 Supplying a DC Motor from a Rotating Generator.- 8. Static Converter as a Power Actuator for DC Drives.- 8.1 Electronic Switching Devices.- 8.2 Line-commutated Converter in Single-phase Bridge Connection.- 8.3 Line-commutated Converter in Three-phase Bridge Connection.- 8.4 Line-commutated Converters with Reduced Reactive Power.- 8.5 Control Loop Containing an Electronic Power Converter.- 9. Control of Converter-supplied DC Drives.- 9.1 DC Drive with Line-commutated Converter.- 9.2 DC Drives with Force-commutated Converters.- 10. Symmetrical Three-Phase AC Machines.- 10.1 Mathematical Model of a General AC Machine.- 10.2 Induction Motor with Sinusoidal Symmetrical Voltages in Steady State.- 10.2.1 Stator Current, Current Locus.- 10.2.2 Steady State Torque, Efficiency.- 10.2.3 Comparison with Practical Motor Designs.- 10.2.4 Starting of the Induction Motor.- 10.3 Induction Motor with Impressed Voltages of Arbitrary Wave- forms.- 10.4 Induction Motor with Unsymmetrical Line Voltages in Steady State.- 10.4.1 Symmetrical Components.- 10.4.2 Single-phase Induction Motor.- 10.4.3 Single-phase Electric Brake for AC Crane-Drives.- 10.4.4 Unsymmetrical Starting Circuit for Induction Motor.- 11. Power Supplies for Adjustable Speed AC Drives.- 11.1 Pulse width modulated (PWM) Voltage Source Transistor Converter (IGBT).- 11.2 Voltage Source PWM Thyristor Converter.- 11.3 Current Source Thyristor Converters.- 11.4 Converter Without DC Link (Cycloconverter).- 12. Control of Induction Motor Drives.- 12.1 Control of Induction Motor Based on Steady State Machine Model.- 12.2 Rotor Flux Orientated Control of Current-fed Induction Motor.- 12.2.1 Principle of Field Orientation.- 12.2.2 Acquisition of Flux Signals.- 12.2.3 Effects of Residual Lag of the Current Control Loops.- 12.2.4 Digital Signal Processing.- 12.2.5 Experimental Results.- 12.2.6 Effects of a Detuned Flux Model.- 12.3 Control of Voltage-fed Induction Motor.- 12.4 Field Orientated Control of Induction Motor with a Current Source Converter.- 12.5 Control of an Induction Motor Without a Mechanical Sensor.- 12.5.1 Machine Model in Stator Flux Coordinates.- 12.5.2 Example of an "Encoderless Control".- 12.5.3 Simulation and Experimental Results.- 12.6 Control of an Induction Motor Using a Combined Flux Model.- 13. Induction Motor Drive with Reduced Speed Range.- 13.1 Doubly-fed Induction Machine with Constant Stator Frequency and Field-orientated Rotor Current.- 13.2 Control of a Line-side Voltage Source Converter as a Reactive Power Compensator.- 13.3 Wound-Rotor Induction with Slip-Power Recovery.- 14. Variable Frequency Synchronous Motor Drives.- 14.1 Control of Synchronous Motors with PM Excitation.- 14.2 Synchronous Motor with Field- and Damper-Windings.- 14.3 Synchronous Motor with Load-commutated Inverter (LCI- Drive).- 15. Some Applications of Controlled Electrical Drives.- 15.1 Speed Controlled Drives.- 15.2 Lineax Position Control.- 15.3 Lineax Position Control with Moving Reference Point.- 15.4 Time-optimal Position Control with Fixed Reference Point.- 15.5 Time-optimal Position Control with Moving Reference Point.

Abstract: 1. Introduction 2. The space-phasor model of A.C. machines 3. Vector and direct torque control of synchronous machines 4. Vector and direct torque control of induction machines 5. Torque control of switched reluctance motors 6. Effects of magnetic saturation 7. Artificial intelligence-based steady-state and transient analysis of electrical machines, estimators 8. Self-commissioning Index

Abstract: The phenomena of stability of synchronous machines under small perturbations is explored by examining the case of a single machine connected to an infinite bus through external reactance.

Abstract: Preface. Part One Introduction. 1. Introduction. 1.1 Introduction. 1.2 Technical Requirements and Challenges. 1.3 Converter Configurations. 1.4 MV Industrial Drives. 1.5 Summary. References. Appendix. 2. High-Power Semiconductor Devices. 2.1 Introduction. 2.2 High-Power Switching Devices. 2.3 Operation of Series-Connected Devices. 2.4 Summary. References. Part Two Multipulse Diode and SCR Rectifiers. 3. Multipulse Diode Rectifiers. 3.1 Introduction. 3.2 Six-Pulse Diode Rectifier. 3.3 Series-Type Multipulse Diode Rectifiers. 3.4 Separate-Type Multipulse Diode Rectifiers. 3.5 Summary.(c) References. 4. Multipulse SCR Rectifiers. 4.1 Introduction. 4.2 Six-Pulse SCR Rectifier. 4.3 12-Pulse SCR Rectifier. 4.4 18- and 24-Pulse SCR Rectifiers. 4.5 Summary. References. 5. Phase-Shifting Transformers. 5.1 Introduction. 5.2 Y/Z Phase-Shifting Transformers. 5.3 /Z Transformers. 5.4 Harmonic Current Cancellation. 5.5 Summary. Part Three Multilevel Voltage Source Converters. 6. Two-Level Voltage Source Inverter. 6.1 Introduction. 6.2 Sinusoidal PWM. 6.3 Space Vector Modulation. 6.4 Summary. References. 7. Cascaded H-Bridge Multilevel Inverters. 7.1 Introduction. 7.2 H-Bridge Inverter. 7.3 Multilevel Inverter Topologies. 7.4 Carrier Based PWM Schemes. 7.5 Staircase Modulation. 7.6 Summary. References. 8. Diode-Clamped Multilevel Inverters. 8.1 Introduction. 8.2 Three-Level Inverter. 8.3 Space Vector Modulation. 8.4 Neutral-Point Voltage Control. 8.5 Other Space Vector Modulation Algorithms. 8.6 High-Level Diode-Clamped Inverters. 8.7 Summary. References. Appendix. 9. Other Multilevel Voltage Source Inverters. 9.1 Introduction. 9.2 NPC/H-Bridge Inverter. 9.3 Multilevel Flying-Capacitor Inverters. 9.4 Summary. References. Part Four PWM Current Source Converters. 10. PWM Current Source Inverters. 10.1 Introduction. 10.2 PWM Current Source Inverter. 10.3 Space Vector Modulation. 10.4 Parallel Current Source Inverters. 10.5 Load-Commutated Inverter (LCI). 10.6 Summary. References. Appendix. 11. PWM Current Source Rectifiers. 11.1 Introduction. 11.2 Single-Bridge Current Source Rectifier. 11.3 Dual-Bridge Current Source Rectifier. 11.4 Power Factor Control . 11.5 Active Damping Control. 11.6 Summary. References. Appendix. Part Five High-Power AC Drives. 12. Voltage Source Inverter-Fed Drives. 12.1 Introduction. 12.2 Two-Level VBSI-Based MV Drives. 12.3 Neutral-Point Clamped (NPC) Inverter-Fed Drives. 12.4 Multilevel Cascaded H-Bridge (CHB) Inverter-Fed Drives. 12.5 NPC/H-Bridge Inverter-Fed Drives. 12.6 Summary. References. 13. Current Source Inverter-Fed Drives. 13.1 Introduction. 13.2 CSI Drives with PWM Rectifiers. 13.3 Transformerless CSI Drive for Standard AC Motors. 13.4 CSI Drive with Multipulse SCR Rectifier. 13.5 LCI Drives for Synchronous Motors. 13.6 Summary. References. 14. Advanced Drive Control Schemes. 14.1 Introduction. 14.2 Reference Frame Transformation. 14.3 Induction Motor Dynamic Models. 14.4 Principle of Field-Oriented Control (FOC). 14.5 Direct Field-Oriented Control. 14.6 Indirect Field-Oriented Control. 14.7 FOC for CSI-Fed Drives. 14.8 Direct Torque Control. 14.9 Summary. References. Abbreviations. Appendix Projects for Graduate-Level Courses. P. 1 Introduction. P. 2 Sample Project. P. 3 Answers to Sample Project. Index. About the Author.