High Performance Control of AC Drives with Matlab/Simulink
Description
Explore this indispensable update to a popular graduate text on electric drive techniques and the latest converters used in industry
The Second Edition of High Performance Control of AC Drives with Matlab¯®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges in the industrial drive system, as well as their components, and control, current source inverter-based drives, PWM techniques for multilevel inverters, and low switching frequency modulation for voltage source inverters.
This book covers three-phase and multiphase (more than three-phase) motor drives including their control and practical problems faced in the field (e.g., adding LC filters in the output of a feeding converter), are considered.
The new edition contains links to Matlab¯®/Simulink models and PowerPoint slides ideal for teaching and understanding the material contained within the book. Readers will also benefit from the inclusion of:
* A thorough introduction to high performance drives, including the challenges and requirements for electric drives and medium voltage industrial applications
* An exploration of mathematical and simulation models of AC machines, including DC motors and squirrel cage induction motors
* A treatment of pulse width modulation of power electronic DC-AC converter, including the classification of PWM schemes for voltage source and current source inverters
* Examinations of harmonic injection PWM and field-oriented control of AC machines
* Voltage source and current source inverter-fed drives and their control
* Modelling and control of multiphase motor drive system
* Supported with a companion website hosting online resources.
Perfect for senior undergraduate, MSc and PhD students in power electronics and electric drives, High Performance Control of AC Drives with Matlab¯®/Simulink will also earn a place in the libraries of researchers working in the field of AC motor drives and power electronics engineers in industry.
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Persons
Haitham Abu-Rub, PhD, is a Fellow of the IEEE and Professor in the Department of Electrical & Computer Engineering, and Managing Director of the Smart Grid Centre, both for Texas A&M University at Qatar. Abu-Rub received two PhDs from Gdansk University of Technology and Gdansk University, Poland, in 1995 and 2004, respectively.
Dr. Atif Iqbal, DSc, PhD, is a Professor in the Department of Electrical Engineering at Qatar University, Doha, Qatar. He obtained his DSc (Habilitation) from Gdansk University of Technology (GUT), Gdansk, Poland in 2019, and his PhD from Liverpool John Moores University, Liverpool, UK in 2006. He is Fellow of IET (UK), Fellow IE (India) and an IEEE Senior Member.
Jaroslaw Guzinski, DSc, PhD, is a Professor at Gdansk University of Technology (GUT), Gdansk, Poland. He is the Vice-Dean for Scientific Research and Head of the Department of Electric Drives and Energy Conversion at the Faculty of Electrical and Control Engineering at GUT. He received his PhD from the Electrical Engineering Department at GUT in 2000 and his DSc degree from the Faculty of Electrical and Control Engineering at GUT in 2011. He is an IEEE Senior Member.
Content
Acknowledgment xiv
Biographies xvi
Preface to Second Edition xviii
Preface to First Edition xx
About the Companion Website xxii
1 Introduction to High-Performance Drives 1
1.1 Preliminary Remarks 1
1.2 General Overview of High-Performance Drives 6
1.3 Challenges and Requirements for Electric Drives for Industrial Applications 10
1.3.1 Power Quality and LC Resonance Suppression 11
1.3.2 Inverter Switching Frequency 12
1.3.3 Motor-Side Challenges 12
1.3.4 High dv/dt and Wave Reflection 12
1.3.5 Use of Inverter Output Filters 13
1.4 Wide Bandgap (WBG) Devices Applications in Electric Motor Drives 14
1.4.1 Industrial Prototype Using WBG 15
1.4.2 Major Challenges for WBG Devices for Electric Motor Drive Applications 15
1.5 Organization of the Book 16
References 19
2 Mathematical and Simulation Models of AC Machines 23
2.1 Preliminary Remarks 23
2.2 DC Motors 23
2.2.1 Separately Excited DC Motor Control 24
2.2.2 Series DC Motor Control 27
2.3 Squirrel Cage Induction Motor 28
2.3.1 Space Vector Representation 28
2.3.2 Clarke Transformation (ABC to aß) 29
2.3.3 Park Transformation (aß to dq) 32
2.3.4 Per Unit Model of Induction Motor 33
2.3.5 Double Fed Induction Generator (DFIG) 36
2.4 Mathematical Model of Permanent Magnet Synchronous Motor 39
2.4.1 Motor Model in dq Rotating Frame 40
2.4.2 Example of Motor Parameters for Simulation 42
2.4.3 PMSM Model in Per Unit System 42
2.4.4 PMSM Model in a - ß (x - y)-Axis 44
2.5 Problems 45
References 45
3 Pulse-Width Modulation of Power Electronic DC-AC Converter 47
Atif Iqbal, Arkadiusz Lewicki, and Marcin Morawiec
3.1 Preliminary Remarks 47
3.2 Classification of PWM Schemes for Voltage Source Inverters 48
3.3 Pulse-Width Modulated Inverters 49
3.3.1 Single-Phase Half-Bridge Inverters 49
3.3.2 Single-Phase Full-Bridge or H-Bridge Inverters 55
3.4 Three-Phase PWM Voltage Source Inverter 60
3.4.1 Carrier-Based Sinusoidal PWM 67
3.4.2 Third-Harmonic Injection Carrier-Based PWM 67
3.4.3 MATLAB/Simulink Model for Third-Harmonic Injection PWM 72
3.4.4 Carrier-Based PWM with Offset Addition 72
3.4.5 Space Vector PWM (SVPWM) 74
3.4.6 Discontinuous Space Vector PWM 79
3.4.7 MATLAB/Simulink Model for Space Vector PWM 84
3.4.8 Space Vector PWM in Overmodulation Region 93
3.4.9 MATLAB/Simulink Model to Implement Space Vector PWM in Overmodulation Regions 99
3.4.10 Harmonic Analysis 100
3.4.11 Artificial Neural Network-Based PWM 100
3.4.12 MATLAB/Simulink Model of Implementing ANN-Based SVPWM 103
3.5 Relationship Between Carrier-Based PWM and SVPWM 104
3.5.1 Modulating Signals and Space Vectors 105
3.5.2 Relationship Between Line-to-Line Voltages and Space Vectors 106
3.5.3 Modulating Signals and Space Vector Sectors 107
3.6 Low-Switching Frequency PWM 107
3.6.1 Types of Symmetries and Fourier Analysis 109
3.6.2 Selective Harmonics Elimination in a two-Level VSI 109
3.6.3 MATLAB Code 114
3.7 Multilevel Inverters 116
3.7.1 Neutral-Point-Clamped (Diode-Clamped) Multilevel Inverters 116
3.7.2 Flying Capacitor-Type Multilevel Inverter 120
3.7.3 Cascaded H-Bridge Multilevel Inverter 126
3.8 Space Vector Modulation and DC-Link Voltage Balancing in Three-Level Neutral-Point-Clamped Inverters 128
3.8.1 The Output Voltage of Three-Level NPC Inverter in the Case of the DC-Link Voltage Unbalance 128
3.8.2 The Space Vector PWM for NPC Inverters 134
3.8.3 MATLAB/Simulink of SVPWM 137
3.9 Space Vector PWM for Multilevel-Cascaded H-Bridge Converter with DC-Link Voltage Balancing 138
3.9.1 Control of a Multilevel CHB Converter 141
3.9.2 The Output Voltage of a Single H-Bridge 142
3.9.3 Three-Level CHB Inverter 143
3.9.4 The Space Vector Modulation for Three-Level CHB Inverter 145
3.9.5 The Space Vector Modulation for Multilevel CHB Inverter 149
3.9.6 MATLAB/Simulink Simulation of SVPWM 150
3.10 Impedance Source or Z-source Inverter 150
3.10.1 Circuit Analysis 154
3.10.2 Carrier-Based Simple Boost PWM Control of a Z-source Inverter 156
3.10.3 Carrier-Based Maximum Boost PWM Control of a Z-source Inverter 157
3.10.4 MATLAB/Simulink Model of Z-source Inverter 159
3.11 Quasi Impedance Source or qZSI Inverter 159
3.11.1 MATLAB/Simulink Model of qZ-source Inverter 164
3.12 Dead Time Effect in a Multiphase Inverter 164
3.13 Summary 169
Problems 169
References 170
4 Field-Oriented Control of AC Machines 177
4.1 Introduction 177
4.2 Induction Machines Control 178
4.2.1 Control of Induction Motor Using V/f Methods 178
4.2.2 Vector Control of Induction Motor 182
4.2.3 Direct and Indirect Field-Oriented Control 188
4.2.4 Rotor and Stator Flux Computation 188
4.2.5 Adaptive Flux Observers 189
4.2.6 Stator Flux Orientation 190
4.2.7 Field Weakening Control 191
4.3 Vector Control of Double Fed Induction Generator (DFIG) 192
4.3.1 Introduction 192
4.3.2 Vector Control of DFIG Connected with the Grid (aß Model) 194
4.3.3 Variables Transformation 194
4.3.4 Simulation Results 198
4.4 Control of Permanent Magnet Synchronous Machine 198
4.4.1 Introduction 198
4.4.2 Vector Control of PMSM in dq Axis 200
4.4.3 Vector Control of PMSM in a-ß Axis Using PI Controller 203
4.4.4 Scalar Control of PMSM 207
Exercises 208
Additional Tasks 208
Possible Tasks for DFIG 208
Questions 208
References 209
5 Direct Torque Control of AC Machines 211
Truc Phamdinh
5.1 Preliminary Remarks 211
5.2 Basic Concept and Principles of DTC 212
5.2.1 Basic Concept 212
5.2.2 Principle of DTC 214
5.3 DTC of Induction Motor with Ideal Constant Machine Model 220
5.3.1 Ideal Constant Parameter Model of Induction Motors 220
5.3.2 Direct Torque Control Scheme 222
5.3.3 Speed Control with DTC 225
5.3.4 MATLAB/Simulink Simulation of Torque Control and Speed Control with DTC 225
5.4 DTC of Induction Motor with Consideration of Iron Loss 240
5.4.1 Induction Machine Model with Iron Loss Consideration 240
5.4.2 MATLAB/SIMULINK Simulation of the Effects of Iron Losses in Torque Control and Speed Control 243
5.4.3 Modified Direct Torque Control Scheme for Iron Loss Compensation 254
5.5 DTC of Induction Motor with Consideration of Both Iron Losses and Magnetic Saturation 259
5.5.1 Induction Machine Model with Consideration of Iron Losses and Magnetic Saturation 259
5.5.2 MATLAB/Simulink Simulation of Effects of Both Iron Losses and Magnetic Saturation in Torque Control and Speed Control 260
5.6 Modified Direct Torque Control of Induction Machine with Constant Switching Frequency 275
5.7 Direct Torque Control of Sinusoidal Permanent Magnet Synchronous Motors (SPMSM) 276
5.7.1 Introduction 276
5.7.2 Mathematical Model of Sinusoidal PMSM 276
5.7.3 Direct Torque Control Scheme of PMSM 278
5.7.4 MATLAB/Simulink Simulation of SPMSM with DTC 278
References 296
6 Nonlinear Control of Electrical Machines Using Nonlinear Feedback 299
Zbigniew Krzeminski and Haitham Abu-Rub
6.1 Introduction 299
6.2 Dynamic System Linearization Using Nonlinear Feedback 300
6.3 Nonlinear Control of Separately Excited DC Motors 301
6.3.1 MATLAB/Simulink Nonlinear Control Model 303
6.3.2 Nonlinear Control Systems 303
6.3.3 Speed Controller 304
6.3.4 Controller for Variable m 304
6.3.5 Field Current Controller 306
6.3.6 Simulation Results 306
6.4 Multiscalar Model (MM) of Induction Motor 306
6.4.1 Multiscalar Variables 307
6.4.2 Nonlinear Linearization of Induction Motor Fed by Voltage Controlled VSI 308
6.4.3 Design of System Control 310
6.4.4 Nonlinear Linearization of Induction Motor Fed by Current Controlled VSI 311
6.4.5 Stator-Oriented Nonlinear Control System (based on ¿s, is) 314
6.4.6 Rotor-Stator Fluxes-Based Model 315
6.4.7 Stator-Oriented Multiscalar Model 316
6.4.8 Multiscalar Control of Induction Motor 318
6.4.9 Induction Motor Model 319
6.4.10 State Transformations 320
6.4.11 Decoupled IM Model 321
6.5 MM of Double-Fed Induction Machine (DFIM) 322
6.6 Nonlinear Control of Permanent Magnet Synchronous Machine 325
6.6.1 Nonlinear Control of PMSM for a dq Motor Model 327
6.6.2 Nonlinear Vector Control of PMSM in a-ß Axis 329
6.6.3 PMSM Model in a-ß (x-y) Axis 329
6.6.4 Transformations 329
6.6.5 Control System 333
6.6.6 Simulation Results 334
6.7 Problems 334
References 334
7 Five-Phase Induction Motor Drive System 337
7.1 Preliminary Remarks 337
7.2 Advantages and Applications of Multiphase Drives 338
7.3 Modeling and Simulation of a Five-Phase Induction Motor Drive 339
7.3.1 Five-Phase Induction Motor Model 339
7.3.2 Five-Phase Two-Level Voltage Source Inverter Model 345
7.3.3 PWM Schemes of a Five-Phase VSI 380
7.4 Direct Rotor Field-Oriented Control of Five-Phase Induction Motor 396
7.4.1 MATLAB/Simulink Model of Field-Oriented Control of Five-Phase Induction Machine 398
7.5 Field-Oriented Control of Five-Phase Induction Motor with Current Control in the Synchronous Reference Frame 402
7.6 Direct Torque Control of a Five-Phase Induction Motor 404
7.6.1 Control of Inverter Switches Using DTC Technique 404
7.6.2 Virtual Vector for Five-Phase Two-Level Inverter 405
7.7 Model Predictive Control (MPC) 420
7.7.1 MPC Applied to a Five-Phase Two-Level VSI 421
7.7.2 MATLAB/Simulink of MPC for Five-Phase VSI 422
7.7.3 Using Eleven Vectors with ¿ = 0 423
7.7.4 Using Eleven Vectors with ¿ = 1 425
7.8 Summary 426
7.9 Problems 426
References 427
8 Sensorless Speed Control of AC Machines 433
8.1 Preliminary Remarks 433
8.2 Sensorless Control of Induction Motor 433
8.2.1 Speed Estimation Using Open-Loop Model and Slip Computation 434
8.2.2 Closed-Loop Observers 434
8.2.3 MRAS (Closed-Loop) Speed Estimator 443
8.2.4 The Use of Power Measurements 446
8.3 Sensorless Control of PMSM 448
8.3.1 Control System of PMSM 450
8.3.2 Adaptive Backstepping Observer 450
8.3.3 Model Reference Adaptive System for PMSM 452
8.3.4 Simulation Results 454
8.4 MRAS-Based Sensorless Control of Five-Phase Induction Motor Drive 454
8.4.1 MRAS-Based Speed Estimator 458
8.4.2 Simulation Results 460
References 464
9 Selected Problems of Induction Motor Drives with Voltage Inverter and Inverter Output Filters 469
9.1 Drives and Filters - Overview 469
9.2 Three-Phase to Two-Phase Transformations 471
9.3 Voltage and Current Common Mode Component 473
9.3.1 MATLAB/Simulink Model of Induction Motor Drive with PWM Inverter and Common Mode Voltage 474
9.4 Induction Motor Common Mode Circuit 477
9.5 Bearing Current Types and Reduction Methods 478
9.5.1 Common Mode Choke 480
9.5.2 Common Mode Transformers 482
9.5.3 Common Mode Voltage Reduction by PWM Modifications 483
9.6 Inverter Output Filters 489
9.6.1 Selected Structures of Inverter Output Filters 489
9.6.2 Inverter Output Filters Design 494
9.6.3 Motor Choke 503
9.6.4 MATLAB/Simulink Model of Induction Motor Drive with PWM Inverter and Differential Mode LC Filter 506
9.7 Estimation Problems in the Drive with Filters 509
9.7.1 Introduction 509
9.7.2 Speed Observer with Disturbances Model 511
9.7.3 Simple Observer Based on Motor Stator Models 514
9.8 Motor Control Problems in the Drive with Filters 516
9.8.1 Introduction 516
9.8.2 Field-Oriented Control 518
9.8.3 Nonlinear Field-Oriented Control 522
9.8.4 Nonlinear Multiscalar Control 526
9.9 Predictive Current Control in the Drive System with Output Filter 530
9.9.1 Control System 530
9.9.2 Predictive Current Controller 534
9.9.3 EMF Estimation Technique 536
9.10 Problems 541
Questions 544
References 545
10 Medium Voltage Drives - Challenges and Trends 549
Haitham Abu-Rub, Sertac Bayhan, Shaikh Moinoddin, Mariusz Malinowski, and Jaroslaw Guzinski
10.1 Introduction 549
10.2 Medium Voltage Drive Topologies 551
10.3 Challenges and Requirements of MV Drives 561
10.3.1 Power Quality and LC Resonance Suppression 561
10.3.2 Inverter Switching Frequency 561
10.3.3 Motor Side Challenges 562
10.4 Summary 569
References 569
11 Current Source Inverter Fed Drive 575
Marcin Morawiec and Arkadiusz Lewicki
11.1 Introduction 575
11.2 Current Source Inverter Structure 576
11.3 Pulse Width Modulation of Current Source Inverter 578
11.4 Mathematical Model of the Current Source Inverter Fed Drive 582
11.5 Control System of an Induction Machine Supplied by a Current Source Inverter 583
11.5.1 Open-Loop Control 583
11.5.2 Direct Field Control of Induction Machine 584
11.6 Control System Model in Matlab/Simulink 587
References 591
Index 593
1
Introduction to High-Performance Drives
1.1 Preliminary Remarks
The function of an electric drives system is the controlled conversion of electrical energy to a mechanical form, and vice versa, via a magnetic field. Electric drive is a multidisciplinary field of study, requiring proper integration of knowledge of electrical machines, actuators, power electronic converters, sensors and instrumentation, control hardware and software, and communication links (Figure 1.1). There have been continued developments in the field of electric drives since the inception of the first principle of electrical motors by Michael Faraday in 1821 [1]. The world dramatically changed after the first induction machine was patented (US Patent 381968) by Nikola Tesla in 1888 [2]. Initial research focused on machine design with the aim of reducing the weight per unit power and increasing the efficiency of the motor. Constant efforts by researchers have led to the development of energy-efficient industrial motors with reduced volume machines. The market is saturated with motors reaching high efficiency of almost 95-96%, resulting in no more significant complaints from users [3]. AC motors are broadly classified into three groups: synchronous, asynchronous (induction), and electronically commutated motors. Asynchronous motors are induction motors with a field wound circuit or with squirrel cage rotors. Synchronous motors run at synchronous speeds decided by the supply frequency (Ns = 120f/P) and are classified into three major types: rotor excited, permanent magnets, and synchronous reluctance types. Electronic commutated machines use the principle of DC machines but replace the mechanical commutator with inverter-based commutations. There are two main types of motors that are classified under this category: brushless DC motors and switched reluctance motors. There are several other variations of these basic configurations of electric machines used for specific applications, such as stepper motors, hysteresis motors, permanent magnet-assisted synchronous reluctance motors, hysteresis-reluctance motors, universal motors, claw pole motors, frictionless active bearing-based motors, linear induction motors, etc. Active magnetic bearing systems work on the principle of magnetic levitation and, therefore, do not require working fluid, such as grease or lubricating oils. This feature is highly desirable in special applications, such as artificial heart or blood pumps, as well as in the oil and gas industry.
Figure 1.1 Electric drive system
Induction motors are called the workhorse of industry due to their widespread use in industrial drives. They are the most rugged and cheap motors available off the shelf. However, their dominance is challenged by permanent magnet synchronous motors (PMSM), because of their high power density and high efficiency due to reduced rotor losses. Nevertheless, the use of PMSMs is still restricted to the high-performance application area, due to their moderate ratings and high cost. PMSMs were developed after the invention of Alnico, a permanent magnet material, in 1930. The desirable characteristics of permanent magnets are their large coercive force and high reminiscence. The former characteristics prevent demagnetization during start and short conditions of motors, and the latter maximizes the air gap flux density. The most used permanent magnet material is neodymium-boron-iron (NdBFe), which has almost 50 times higher B-H energy compared to Alnico. The major shortcomings of permanent magnet machines are the nonadjustable flux, irreversible demagnetization, and expensive rare-earth magnet resources. Variable flux permanent magnet (VFPM) machines have been developed to incorporate the adjustable flux feature. This variable flux feature offers flexibility by optimizing efficiency over the whole machine operation range, enhancing torque at low speed, extending the high speed operating range, and reducing the likelihood of an excessively high back-electromotive force (EMF) being induced at high speed during inverter fault conditions. The VFPMs are broadly classified into hybrid-excited machines (they have the field coils and the permanent magnets) and mechanically adjusted permanent magnet machines. Detailed reviews on the variable flux machines are given in [4]. The detailed reviews on the advances on electric motors are presented in [5-16].
Figure 1.2 General view of a DFIG connected to wind system and utility grid
Another popular class of electrical machine is the double-fed induction machine (DFIM) with a wound rotor. The DFIM is frequently used as an induction generator in wind energy systems. The double-fed induction generator (DFIG) is a rotor-wound, three-phase induction machine that is connected to the AC supply from both stator and rotor terminals (Figure 1.2). The stator windings of the machine are connected to the utility grid without using power converters, and the rotor windings are fed by an active front-end converter. Alternatively, the machine can be fed by current or voltage source inverters with controlled voltage magnitude and frequency [17-22].
In the control schemes of DFIM, two output variables on the stator side are generally defined. These variables could be electromagnetic torque and reactive power, active and reactive power, or voltage and frequency, with each pair of variables being controlled by different structures.
The machine is popular and widely adopted for high-power wind generation systems and other types of generators with similar variable-speed high-power sources (e.g. hydro systems). The advantage of using this type of machine is that the required converter capacity is up to three times lower than those that connect the converter to the stator side. Hence, the costs and losses in the conversion system are drastically reduced [17].
A DFIG can be used either in an autonomous generation system (stand-alone) or, more commonly, in parallel with the grid. If the machine is working autonomously, the stator voltage and frequency are selected as the controlled signals. However, when the machine is connected to the infinite bus, the stator voltage and frequency are dictated by the grid system. In the grid-interactive system, the controlled variables are the active and reactive powers [23-25]. Indeed, there are different types of control strategies for this type of machine; however, the most widely used is vector control, which has different orientation frames similar to the squirrel cage induction motor; however, the most popular of these is the stator orientation scheme.
Power electronics converters are used as an interface between the stiff voltage and frequency grid system and the electric motors to provide adjustable voltage and frequency. This is the most vital part of a drive system that provides operational flexibility. The development in power electronic switches is steady, and nowadays high-frequency low-loss power semiconductor devices are available for manufacturing efficient power electronic converters. The power electronic converter can be used as DC-DC (buck, buck-boost, boost converters), AC-DC (rectifiers), DC-AC (inverters), and AC-AC (cycloconverters and matrix converters) modes. In AC drive systems, inverters are used with two-level output or multilevel output (particularly for higher-power applications). The input side of the inverter system can consist of a diode-based, uncontrolled rectifier or controlled rectifier for regeneration capability called back-to-back or active front-end converter. The conventional two-level inverter has the disadvantages of the poor source-side (grid-side) power factor and distorted source current. The situation is improved by using back-to-back converters or matrix converters in drive systems.
The output-side (AC) voltage/current waveforms are improved by employing the appropriate pulse width modulation (PWM) technique, in addition to using a multilevel inverter system. In modern motor drives, the transistor-based [insulated gate bipolar transistor (IGBT), integrated gate-commutated thyristor (IGCT), MOSFET] converters are most commonly used. The increase in transistors switching frequency and decrease in transistor switching times are a source of some serious problems. The high dv/dt and the common-mode (CM) voltage generated by the inverter PWM control result in undesirable bearing currents, shaft voltages, motor terminal overvoltages, reduced motor efficiency, acoustic noise, and electromagnetic interference (EMI) problems, which are aggravated by the long length of the cable between the converter and the motor. To alleviate such problems, generally, the passive LC filters are installed on the converter output. However, the use of an LC filter introduces unwanted voltage drops and causes a phase shift between the filter input and output voltages and currents. These can negatively influence the operation of the whole drive system, especially when sophisticated speed, sensorless control methods are employed, requiring some estimation and control modifications for an electric drive system with an LC filter at its output. With the LC filter, the principal problem is that the motor input voltages and currents are not precisely known; hence, additional voltage and current sensors...
