Advanced Electric Drives

Ned Mohan 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 four other books published by Wiley, and is a member of the National Academy of Engineering.

• Preface xiiiNotation xv1 Applications: Speed and Torque Control 11-1 History 11-2 Background 21-3 Types of ac Drives Discussed and the Simulation Software 21-4 Structure of this Textbook 31-5 “Test” Induction Motor 31-6 Summary 4References 4Problems 42 Induction Machine Equations in Phase Quantities: Assisted by Space Vectors 62-1 Introduction 62-2 Sinusoidally Distributed Stator Windings 62-2-1 Three-Phase, Sinusoidally Distributed Stator Windings 82-3 Stator Inductances (Rotor Open-Circuited) 92-3-1 Stator Single-Phase Magnetizing Inductance Lm,1-phase 92-3-2 Stator Mutual-Inductance Lmutual 112-3-3 Per-Phase Magnetizing-Inductance Lm 122-3-4 Stator-Inductance Ls 122-4 Equivalent Windings in a Squirrel-Cage Rotor 132-4-1 Rotor-Winding Inductances (Stator Open-Circuited) 132-5 Mutual Inductances between the Stator and the Rotor Phase Windings 152-6 Review of Space Vectors 152-6-1 Relationship between Phasors and Space Vectors in Sinusoidal Steady State 172-7 Flux Linkages 182-7-1 Stator Flux Linkage (Rotor Open-Circuited) 182-7-2 Rotor Flux Linkage (Stator Open-Circuited) 192-7-3 Stator and Rotor Flux Linkages (Simultaneous Stator and Rotor Currents) 202-8 Stator and Rotor Voltage Equations in Terms of Space Vectors 212-9 Making the Case for a dq -Winding Analysis 222-10 Summary 25Reference 25Problems 263 Dynamic Analysis of Induction Machines in Terms of dq Windings 283-1 Introduction 283-2 dq Winding Representation 283-2-1 Stator dq Winding Representation 293-2-2 Rotor dq Windings (Along the Same dq-Axes as in the Stator) 313-2-3 Mutual Inductance between dq Windings on the Stator and the Rotor 323-3 Mathematical Relationships of the dq Windings (at an Arbitrary Speed ωd) 333-3-1 Relating dq Winding Variables to Phase Winding Variables 353-3-2 Flux Linkages of dq Windings in Terms of Their Currents 363-3-3 dq Winding Voltage Equations 373-3-4 Obtaining Fluxes and Currents with Voltages as Inputs 403-4 Choice of the dqWinding Speed ωd 413-5 Electromagnetic Torque 423-5-1 Torque on the Rotor d -Axis Winding 423-5-2 Torque on the Rotor q -Axis Winding 433-5-3 Net Electromagnetic Torque Tem on the Rotor 443-6 Electrodynamics 443-7 d- and q-Axis Equivalent Circuits 453-8 Relationship between the dq Windings and the Per-Phase Phasor-Domain Equivalent Circuit in Balanced Sinusoidal Steady State 463-9 Computer Simulation 473-9-1 Calculation of Initial Conditions 483-10 Summary 56Reference 56Problems 574 Vector Control of Induction-Motor Drives: A Qualitative Examination 594-1 Introduction 594-2 Emulation of dc and Brushless dc Drive Performance 594-2-1 Vector Control of Induction-Motor Drives 614-3 Analogy to a Current-Excited Transformer with a Shorted Secondary 624-3-1 Using the Transformer Equivalent Circuit 654-4 d- and q -Axis Winding Representation 664-5 Vector Control with d-Axis Aligned with the Rotor Flux 674-5-1 Initial Flux Buildup Prior to t = 0−674-5-2 Step Change in Torque at t = 0+684-6 Torque, Speed, and Position Control 724-6-1 The Reference Current isq t * ( ) 724-6-2 The Reference Current isd t ( ) 734-6-3 Transformation and Inverse-Transformation of Stator Currents 734-6-4 The Estimated Motor Model for Vector Control 744-7 The Power-Processing Unit (PPU) 754-8 Summary 76References 76Problems 775 Mathematical Description of Vector Control in Induction Machines 795-1 Motor Model with the d-Axis Aligned Along the Rotor Flux Linkage λ r-Axis 795-1-1 Calculation of ωdA 815-1-2 Calculation of Tem 815-1-3 d-Axis Rotor Flux Linkage Dynamics 825-1-4 Motor Model 825-2 Vector Control 845-2-1 Speed and Position Control Loops 865-2-2 Initial Startup 895-2-3 Calculating the Stator Voltages to Be Applied 895-2-4 Designing the PI Controllers 905-3 Summary 95Reference 95Problems 956 Detuning Effects in Induction Motor Vector Control 976-1 Effect of Detuning Due to Incorrect Rotor Time Constant τr 976-2 Steady-State Analysis 1016-2-1 Steady-State isd /is*d 1046-2-2 Steady-State isq /is*q 1046-2-3 Steady-State θerr 1056-2-4 Steady-State Tem /Te*m 1066-3 Summary 107References 107Problems 1087 Dynamic Analysis of Doubly Fed Induction Generators and Their Vector Control 1097-1 Understanding DFIG Operation 1107-2 Dynamic Analysis of DFIG 1167-3 Vector Control of DFIG 1167-4 Summary 117References 117Problems 1178 Space Vector Pulse Width-Modulated (SV-PWM) Inverters 1198-1 Introduction 1198-2 Synthesis of Stator Voltage Space Vector vsa 1198-3 Computer Simulation of SV-PWM Inverter 1248-4 Limit on the Amplitude ˆVs of the Stator Voltage Space Vectov sa 125Summary 128References 128Problems 1299 Direct Torque Control (DTC) and Encoderless Operation of Induction Motor Drives 1309-1 Introduction 1309-2 System Overview 1309-3 Principle of Encoderless DTC Operation 1319-4 Calculation of λs, λ r, Tem, and ωm 1329-4-1 Calculation of the Stator Flux λ s 1329-4-2 Calculation of the Rotor Flux λ r 1339-4-3 Calculation of the Electromagnetic Torque Tem 1349-4-4 Calculation of the Rotor Speed ωm 1359-5 Calculation of the Stator Voltage Space Vector 1369-6 Direct Torque Control Using dq-Axes 1399-7 Summary 139References 139Problems 139Appendix 9-A 140Derivation of Torque Expressions 14010 Vector Control of Permanent-Magnet Synchronous Motor Drives 14310-1 Introduction 14310-2 d-q Analysis of Permanent Magnet (Nonsalient-Pole) Synchronous Machines 14310-2-1 Flux Linkages 14410-2-2 Stator dq Winding Voltages 14410-2-3 Electromagnetic Torque 14510-2-4 Electrodynamics 14510-2-5 Relationship between the dq Circuits and the Per-Phase Phasor-Domain Equivalent Circuit in Balanced Sinusoidal Steady State 14510-2-6 dq-Based Dynamic Controller for “Brushless DC” Drives 14710-3 Salient-Pole Synchronous Machines 15110-3-1 Inductances 15210-3-2 Flux Linkages 15310-3-3 Winding Voltages 15310-3-4 Electromagnetic Torque 15410-3-5 dq-Axis Equivalent Circuits 15410-3-6 Space Vector Diagram in Steady State 15410-4 Summary 156References 156Problems 15611 Switched-Reluctance Motor (SRM) Drives 15711-1 Introduction 15711-2 Switched-Reluctance Motor 15711-2-1 Electromagnetic Torque Tem 15911-2-2 Induced Back-EMF ea 16111-3 Instantaneous Waveforms 16211-4 Role of Magnetic Saturation 16411-5 Power Processing Units for SRM Drives 16511-6 Determining the Rotor Position for Encoderles Operation 16611-7 Control in Motoring Mode 16611-8 Summary 167References 167Problems 167Index 169