ix Contents Chapter 7 Electric Machines ..................................................................................................... 179 7.1 Simple Electric Machines .............................................................................. 180 7.1.1 Fundamental Machine Phenomena .................................................. 180 7.1.1.1 Motional Voltage B ........................................................... 180 7.1.1.2 Electromagnetic Force ...................................................... 181 7.1.2 Simple DC Machine .........................................................................
181 7.1.2.1 Induced Voltage ................................................................ 181 7.1.2.2 Force and Torque .............................................................. 183 7.1.2.3 DC Machine Back-EMF and Torque ................................ 184 7.1.3 Simple Reluctance Machine ............................................................. 185 7.2 Materials for Electric Machines .................................................................... 186 7.2.1 Conductors ........................................................................................ 186 7.2.2 Magnetic Materials ..........................................................................
187 7.3 DC Machines .................................................................................................190 7.4 Three-Phase AC Machines ............................................................................192 7.4.1 Sinusoidal Stator Windings .............................................................. 193 7.4.2 Number of Poles ............................................................................... 195 7.4.3 Three-Phase Sinusoidal Windings ................................................... 195 7.4.4 Space Vector Representation ............................................................
195 7.4.4.1 Interpretation of Space Vectors ........................................199 7.4.4.2 Inverse Relations ...............................................................199 7.4.4.3 Resultant mmf in a Balanced System ...............................200 7.4.4.4 Mutual Inductance L m and Induced Stator Voltage ..........201 7.4.5 Types of AC Machines .....................................................................202 7.4.6 dq Modeling .....................................................................................202 7.5 Induction Machines .......................................................................................204 7.5.1 Per-Phase Equivalent Circuit ............................................................206 7.5.2 Simplified Torque Expression ..........................................................208 7.5.3 Regenerative Braking .......................................................................
211 7.6 Permanent Magnet Machines ........................................................................ 212 7.6.1 PM Synchronous Motors .................................................................. 213 7.6.1.1 Surface PMSM Flux and Torque ...................................... 214 7.6.1.2 Interior PMSM Flux and Torque ...................................... 217 7.6.2 PM Brushless DC Motors ................................................................ 218 7.6.2.1 PM BLDC Machine Modeling .........................................
218 7.7 Reluctance Machines .....................................................................................220 7.7.1 Synchronous Reluctance Machines ..................................................220 7.7.2 PM Assisted Synchronous Reluctance Machines ............................222 7.7.3 Switched Reluctance Machines ........................................................222 7.7.3.1 SRM Principles of Operation ...........................................223 7.7.3.2 Energy Conversion ............................................................225 7.7.3.3 Torque Production .............................................................226 7.8 Traction IPM Machine Design ......................................................................227 7.8.1 Initial Machine Sizing:
Electromagnetic Design .............................228 7.8.2 Thermal Analysis .............................................................................228 7.8.3 Mechanical/Structural Analysis .......................................................228 7.8.4 Stator and Winding Designs .............................................................229 7.8.5 Rotor Design .....................................................................................230 Problems ...................................................................................................................234 References ................................................................................................................235