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<p>Preface xiii</p> <p>Notation xv</p> <p><b>1 Applications: Speed and Torque Control 1</b></p> <p>1-1 History 1</p> <p>1-2 Background 2</p> <p>1-3 Types of ac Drives Discussed and the Simulation Software 2</p> <p>1-4 Structure of this Textbook 3</p> <p>1-5 “Test” Induction Motor 3</p> <p>1-6 Summary 4</p> <p>References 4</p> <p>Problems 4</p> <p><b>2 Induction Machine Equations in Phase Quantities: Assisted by Space Vectors 6</b></p> <p>2-1 Introduction 6</p> <p>2-2 Sinusoidally Distributed Stator Windings 6</p> <p>2-2-1 Three-Phase, Sinusoidally Distributed Stator Windings 8</p> <p>2-3 Stator Inductances (Rotor Open-Circuited) 9</p> <p>2-3-1 Stator Single-Phase Magnetizing Inductance <i>L</i>m,1-phase 9</p> <p>2-3-2 Stator Mutual-Inductance <i>L</i>mutual 11</p> <p>2-3-3 Per-Phase Magnetizing-Inductance <i>L</i>m 12</p> <p>2-3-4 Stator-Inductance <i>L</i>s 12</p> <p>2-4 Equivalent Windings in a Squirrel-Cage Rotor 13</p> <p>2-4-1 Rotor-Winding Inductances (Stator Open-Circuited) 13</p> <p>2-5 Mutual Inductances between the Stator and the Rotor Phase Windings 15</p> <p>2-6 Review of Space Vectors 15</p> <p>2-6-1 Relationship between Phasors and Space Vectors in Sinusoidal Steady State 17</p> <p>2-7 Flux Linkages 18</p> <p>2-7-1 Stator Flux Linkage (Rotor Open-Circuited) 18</p> <p>2-7-2 Rotor Flux Linkage (Stator Open-Circuited) 19</p> <p>2-7-3 Stator and Rotor Flux Linkages (Simultaneous Stator and Rotor Currents) 20</p> <p>2-8 Stator and Rotor Voltage Equations in Terms of Space Vectors 21</p> <p>2-9 Making the Case for a <i>dq</i> -Winding Analysis 22</p> <p>2-10 Summary 25</p> <p>Reference 25</p> <p>Problems 26</p> <p><b>3 Dynamic Analysis of Induction Machines in Terms of <i>dq</i> Windings 28</b></p> <p>3-1 Introduction 28</p> <p>3-2 <i>dq</i> Winding Representation 28</p> <p>3-2-1 Stator <i>dq</i> Winding Representation 29</p> <p>3-2-2 Rotor <i>dq</i> Windings (Along the Same dq-Axes as in the Stator) 31</p> <p>3-2-3 Mutual Inductance between <i>dq</i> Windings on the Stator and the Rotor 32</p> <p>3-3 Mathematical Relationships of the <i>dq</i> Windings (at an Arbitrary Speed <i>ω</i>d) 33</p> <p>3-3-1 Relating <i>dq</i> Winding Variables to Phase Winding Variables 35</p> <p>3-3-2 Flux Linkages of <i>dq</i> Windings in Terms of Their Currents 36</p> <p>3-3-3 <i>dq</i> Winding Voltage Equations 37</p> <p>3-3-4 Obtaining Fluxes and Currents with Voltages as Inputs 40</p> <p>3-4 Choice of the <i>dq</i>Winding Speed <i>ω</i>d 41</p> <p>3-5 Electromagnetic Torque 42</p> <p>3-5-1 Torque on the Rotor <i>d</i> -Axis Winding 42</p> <p>3-5-2 Torque on the Rotor <i>q</i> -Axis Winding 43</p> <p>3-5-3 Net Electromagnetic Torque <i>T</i>em on the Rotor 44</p> <p>3-6 Electrodynamics 44</p> <p>3-7 <i>d</i>- and <i>q</i>-Axis Equivalent Circuits 45</p> <p>3-8 Relationship between the <i>dq</i> Windings and the Per-Phase Phasor-Domain Equivalent Circuit in Balanced Sinusoidal Steady State 46</p> <p>3-9 Computer Simulation 47</p> <p>3-9-1 Calculation of Initial Conditions 48</p> <p>3-10 Summary 56</p> <p>Reference 56</p> <p>Problems 57</p> <p><b>4 Vector Control of Induction-Motor Drives: A Qualitative Examination 59</b></p> <p>4-1 Introduction 59</p> <p>4-2 Emulation of dc and Brushless dc Drive Performance 59</p> <p>4-2-1 Vector Control of Induction-Motor Drives 61</p> <p>4-3 Analogy to a Current-Excited Transformer with a Shorted Secondary 62</p> <p>4-3-1 Using the Transformer Equivalent Circuit 65</p> <p>4-4 <i>d</i>- and <i>q</i> -Axis Winding Representation 66</p> <p>4-5 Vector Control with <i>d</i>-Axis Aligned with the Rotor Flux 67</p> <p>4-5-1 Initial Flux Buildup Prior to <i>t</i> = 0−67</p> <p>4-5-2 Step Change in Torque at <i>t</i> = 0+68</p> <p>4-6 Torque, Speed, and Position Control 72</p> <p>4-6-1 The Reference Current <i>isq</i> <i>t</i> * ( ) 72</p> <p>4-6-2 The Reference Current <i>isd</i> <i>t </i>( ) 73</p> <p>4-6-3 Transformation and Inverse-Transformation of Stator Currents 73</p> <p>4-6-4 The Estimated Motor Model for Vector Control 74</p> <p>4-7 The Power-Processing Unit (PPU) 75</p> <p>4-8 Summary 76</p> <p>References 76</p> <p>Problems 77</p> <p><b>5 Mathematical Description of Vector Control in Induction Machines 79</b></p> <p>5-1 Motor Model with the <i>d</i>-Axis Aligned Along the Rotor Flux Linkage λ <i>r</i>-Axis 79</p> <p>5-1-1 Calculation of <i>ω</i>dA 81</p> <p>5-1-2 Calculation of <i>T</i>em 81</p> <p>5-1-3 <i>d</i>-Axis Rotor Flux Linkage Dynamics 82</p> <p>5-1-4 Motor Model 82</p> <p>5-2 Vector Control 84</p> <p>5-2-1 Speed and Position Control Loops 86</p> <p>5-2-2 Initial Startup 89</p> <p>5-2-3 Calculating the Stator Voltages to Be Applied 89</p> <p>5-2-4 Designing the PI Controllers 90</p> <p>5-3 Summary 95</p> <p>Reference 95</p> <p>Problems 95</p> <p><b>6 Detuning Effects in Induction Motor Vector Control 97</b></p> <p>6-1 Effect of Detuning Due to Incorrect Rotor Time Constant <i>τ</i>r 97</p> <p>6-2 Steady-State Analysis 101</p> <p>6-2-1 Steady-State <i>i</i>sd /<i>i</i>s*<i>d</i> 104</p> <p>6-2-2 Steady-State <i>i</i>sq /<i>i</i>s*<i>q</i> 104</p> <p>6-2-3 Steady-State <i>θ</i>err 105</p> <p>6-2-4 Steady-State <i>T</i>em /<i>T</i>e*<i>m</i> 106</p> <p>6-3 Summary 107</p> <p>References 107</p> <p>Problems 108</p> <p><b>7 Dynamic Analysis of Doubly Fed Induction Generators and Their Vector Control 109</b></p> <p>7-1 Understanding DFIG Operation 110</p> <p>7-2 Dynamic Analysis of DFIG 116</p> <p>7-3 Vector Control of DFIG 116</p> <p>7-4 Summary 117</p> <p>References 117</p> <p>Problems 117</p> <p><b>8 Space Vector Pulse Width-Modulated (SV-PWM) Inverters 119</b></p> <p>8-1 Introduction 119</p> <p>8-2 Synthesis of Stator Voltage Space Vector vsa 119</p> <p>8-3 Computer Simulation of SV-PWM Inverter 124</p> <p>8-4 Limit on the Amplitude ˆ<i>V</i>s of the Stator Voltage Space Vectov sa 125</p> <p>Summary 128</p> <p>References 128</p> <p>Problems 129</p> <p><b>9 Direct Torque Control (DTC) and Encoderless Operation of Induction Motor Drives 130</b></p> <p>9-1 Introduction 130</p> <p>9-2 System Overview 130</p> <p>9-3 Principle of Encoderless DTC Operation 131</p> <p>9-4 Calculation of λ<i>s</i>, λ <i>r</i>, <i>T</i>em, and <i>ω</i>m 132</p> <p>9-4-1 Calculation of the Stator Flux λ <i>s</i> 132</p> <p>9-4-2 Calculation of the Rotor Flux λ <i>r</i> 133</p> <p>9-4-3 Calculation of the Electromagnetic Torque <i>T</i>em 134</p> <p>9-4-4 Calculation of the Rotor Speed <i>ω</i>m 135</p> <p>9-5 Calculation of the Stator Voltage Space Vector 136</p> <p>9-6 Direct Torque Control Using <i>dq</i>-Axes 139</p> <p>9-7 Summary 139</p> <p>References 139</p> <p>Problems 139</p> <p>Appendix 9-A 140</p> <p>Derivation of Torque Expressions 140</p> <p><b>10 Vector Control of Permanent-Magnet Synchronous Motor Drives 143</b></p> <p>10-1 Introduction 143</p> <p>10-2 <i>d-q</i> Analysis of Permanent Magnet (Nonsalient-Pole) Synchronous Machines 143</p> <p>10-2-1 Flux Linkages 144</p> <p>10-2-2 Stator <i>dq</i> Winding Voltages 144</p> <p>10-2-3 Electromagnetic Torque 145</p> <p>10-2-4 Electrodynamics 145</p> <p>10-2-5 Relationship between the <i>dq</i> Circuits and the Per-Phase Phasor-Domain Equivalent Circuit in Balanced Sinusoidal Steady State 145</p> <p>10-2-6 <i>dq</i>-Based Dynamic Controller for “Brushless DC” Drives 147</p> <p>10-3 Salient-Pole Synchronous Machines 151</p> <p>10-3-1 Inductances 152</p> <p>10-3-2 Flux Linkages 153</p> <p>10-3-3 Winding Voltages 153</p> <p>10-3-4 Electromagnetic Torque 154</p> <p>10-3-5 <i>dq</i>-Axis Equivalent Circuits 154</p> <p>10-3-6 Space Vector Diagram in Steady State 154</p> <p>10-4 Summary 156</p> <p>References 156</p> <p>Problems 156</p> <p><b>11 Switched-Reluctance Motor (SRM) Drives 157</b></p> <p>11-1 Introduction 157</p> <p>11-2 Switched-Reluctance Motor 157</p> <p>11-2-1 Electromagnetic Torque <i>T</i>em 159</p> <p>11-2-2 Induced Back-EMF <i>e</i>a 161</p> <p>11-3 Instantaneous Waveforms 162</p> <p>11-4 Role of Magnetic Saturation 164</p> <p>11-5 Power Processing Units for SRM Drives 165</p> <p>11-6 Determining the Rotor Position for Encoderles Operation 166</p> <p>11-7 Control in Motoring Mode 166</p> <p>11-8 Summary 167</p> <p>References 167</p> <p>Problems 167</p> <p>Index 169</p>

<b>Ned Mohan</b> is the Oscar A. Schott Professor of Power Electronics at the University of Minnesota. A holder of numerous patents in the field, Mohan is the author of <i>four other books published by Wiley</i>, and is a member of the National Academy of Engineering.

With nearly two-thirds of global electricity consumed by electric motors, it should come as no surprise that their proper control represents appreciable energy savings. The efficient use of electric drives also has far-reaching applications in such areas as factory automation (robotics), clean transportation (hybrid-electric vehicles), and renewable (wind and solar) energy resource management. <i>Advanced Electric Drives</i> utilizes a physics-based approach to explain the fundamental concepts of modern electric drive control and its operation under dynamic conditions. Author Ned Mohan, a decades-long leader in Electrical Energy Systems (EES) education and research, reveals how the investment of proper controls, advanced MATLAB and Simulink simulations, and careful forethought in the design of energy systems translates to significant savings in energy and dollars. Offering students a fresh alternative to standard mathematical treatments of dq-axis transformation of a-b-c phase quantities, Mohan’s unique physics-based approach “visualizes” a set of representative dq windings along an orthogonal set of axes and then relates their currents and voltages to the a-b-c phase quantities. <i>Advanced Electric Drives</i> is an invaluable resource to facilitate an understanding of the analysis, control, and modelling of electric machines.

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