Variable Speed Generators: 2nd Edition (Hardback) book cover

Variable Speed Generators

2nd Edition

By Ion Boldea

CRC Press

580 pages | 456 B/W Illus.

Purchasing Options:$ = USD
Hardback: 9781498723572
pub: 2015-10-06
SAVE ~$35.00
eBook (VitalSource) : 9781315214177
pub: 2015-09-03
from $28.98

FREE Standard Shipping!


Variable Speed Generators, the second of two volumes in the Electric Generators Handbook, provides extensive coverage of variable speed generators in distributed generation and renewable energy applications around the world. The book delves into the steady state, transients, control, and design of claw-pole-rotor synchronous, induction, permanent-magnet-(PM)-assisted synchronous, and switched reluctance starter alternators for electric hybrid vehicles. It discusses PM synchronous, transverse flux PM, and flux reversal PM generators for low-speed wind and hydro energy conversion. It also explores linear motion alternators for residential and spacecraft applications. Numerous design and control examples illustrate the exposition.

Fully revised and updated to reflect the last decade’s worth of progress in the field, this Second Edition adds new sections that:

  • Address the ride-through control of doubly fed induction generators under unbalanced voltage sags
  • Consider the control of stand-alone doubly fed induction generators under unbalanced nonlinear loads
  • Detail a stand-alone squirrel cage induction generator (SCIG) with AC output and a low-rating pulse-width modulated (PWM) converter
  • Present a twin stator winding SCIG with 50 percent rating inverter and diode rectifier, and a dual stator winding induction generator with nested cage rotor
  • Examine interior permanent magnet claw-pole-alternator systems for more vehicle braking energy recuperation, and high power factor Vernier PM generators
  • Depict a PM-assisted reluctance synchronous motor/generator for an electric hybrid vehicle, and a double stator switched reluctance generator with segmented rotor
  • Describe the grid to stand-alone transition motion-sensorless dual-inverter control of permanent magnet synchronous generators with asymmetrical grid voltage sags and harmonics filtering

The promise of renewable, sustainable energy rests on our ability to design innovative power systems that are able to harness energy from a variety of sources. Variable Speed Generators, Second Edition supplies state-of-the-art tools necessary to design, validate, and deploy the right power generation technologies to fulfill tomorrow's complex energy needs.

Table of Contents

Wound-Rotor Induction Generators: Steady State


Construction Elements

Steady-State Equations

Equivalent Circuit

Phasor Diagrams

Operation at the Power Grid

Autonomous Operation of WRIGs

Operation of WRIGs in the Brushless Exciter Mode

Losses and Efficiency of WRIGs



Wound-Rotor Induction Generators: Transients and Control


WRIG Phase Coordinate Model

Space-Phasor Model of WRIG

Space-Phasor Equivalent Circuits and Diagrams

Approaches to WRIG Transients

Static Power Converters for WRIGs

Vector Control of WRIG at Power Grid

Direct Power Control of WRIG at Power Grid

Independent Vector Control of Positive and Negative Sequence Currents

Motion-Sensorless Control

Vector Control in Stand-Alone Operation

Self-Starting, Synchronization, and Loading at the Power Grid

Voltage and Current Low-Frequency Harmonics of WRIG

Ride-Through Control of DFIG under Unbalanced Voltage Sags

Stand-Alone DFIG Control under Unbalanced Nonlinear Loads



Wound-Rotor Induction Generators: Design and Testing


Design Specifications: An Example

Stator Design

Rotor Design

Magnetization Current

Reactances and Resistances

Electrical Losses and Efficiency

Testing of WRIGs



Self-Excited Induction Generators


Principle of Cage-Rotor Induction Machine

Self-Excitation: A Qualitative View

Steady-State Performance of Three-Phase SEIGs

Performance Sensitivity Analysis

Pole Changing SEIGs for Variable Speed Operation

Unbalanced Operation of Three-Phase SEIGs

One Phase Open at Power Grid

Three-Phase SEIG with Single-Phase Output

Two-Phase SEIGs with Single-Phase Output

Three-Phase SEIG Transients

Parallel Connection of SEIGs

Direct Connection to Grid Transients in Cage-Rotor Induction Generators

More on Power Grid Disturbance Transients in Cage-Rotor Induction Generators



Stator-Converter-Controlled Induction Generators


Grid-Connected SCIGs: The Control System

Grid Connection and Four-Quadrant Operation of SCIGs

Stand-Alone Operation of SCIG

Parallel Operation of SCIGs

Static Capacitor Exciter Stand-Alone IG for Pumping Systems

Operation of SCIGs with DC Voltage-Controlled Output

Stand-Alone SCIG with AC Output and Low Rating PWM Converter

Dual Stator Winding for Grid Applications

Twin Stator Winding SCIG with 50% Rating Inverter and Diode Rectifier

Dual Stator Winding IG with Nested Cage Rotor



Automotive Claw-Pole-Rotor Generator Systems


Construction and Principle

Magnetic Equivalent Circuit Modeling

Three-Dimensional Finite Element Method Modeling

Losses, Efficiency, and Power Factor

Design Improvement Steps

Lundell Starter/Generator for Hybrid Vehicles

IPM Claw-Pole Alternator System for More Vehicle Braking Energy Recuperation: A Case Study



Induction Starter/Alternators for Electric Hybrid Vehicles

Electric Hybrid Vehicle Configuration

Essential Specifications

Topology Aspects of Induction Starter/Alternator

ISA Space-Phasor Model and Characteristics

Vector Control of ISA


ISA Design Issues for Variable Speed



Permanent-Magnet-Assisted Reluctance Synchronous Starter/Alternators for Electric Hybrid Vehicles


Topologies of PM-RSM

Finite Element Analysis

dq Model of PM-RSM

Steady-State Operation at No Load and Symmetric Short Circuit

Design Aspects for Wide Speed Range Constant Power Operation

Power Electronics for PM-RSM for Automotive Applications

Control of PM-RSM for EHV

State Observers without Signal Injection for Motion Sensorless Control

Signal Injection Rotor Position Observers

Initial and Low-Speed Rotor Position Tracking

50/100 kW, 1350–7000 rpm (600 Nm Peak Torque, 40 kg) PM-Assisted Reluctance Synchronous Motor/Generator for HEV: A Case Study



Switched Reluctance Generators and Their Control


Practical Topologies and Principles of Operation

SRG(M) Modeling

Flux/Current/Position Curves

Design Issues

PWM Converters for SRGs

Control of SRG(M)s

Direct Torque Control of SRG(M)

Rotor Position and Speed Observers for Motion-Sensorless Control

Output Voltage Control in SRG

Double Stator SRG with Segmented Rotor



Permanent Magnet Synchronous Generator Systems


Practical Configurations and Their Characterization

Air Gap Field Distribution, emf, and Torque

Stator Core Loss Modeling

Circuit Model

Circuit Model of PMSG with Shunt Capacitors and AC Load

Circuit Model of PMSG with Diode Rectifier Load

Utilization of Third Harmonic for PMSG with Diode Rectifiers

Autonomous PMSGs with Controlled Constant Speed and AC Load

Grid-Connected Variable-Speed PMSG System

PM Genset with Multiple Outputs

Super-High-Speed PM Generators: Design Issues

Super-High-Speed PM Generators: Power Electronics Control Issues

Design of a 42 Vdc Battery-Controlled-Output PMSG System

Methods for Testing PMSGs

Grid to Stand-Alone Transition Motion-Sensorless Dual-Inverter Control of PMSG with Asymmetrical Grid Voltage Sags and Harmonics Filtering: A Case Study

Note on Medium-Power Vehicular Electric Generator Systems



Transverse Flux and Flux Reversal Permanent Magnet Generator Systems


Three-Phase Transverse Flux Machine: Magnetic Circuit Design

TFM: The dq Model and Steady State

Three-Phase FR-PM Generator: Magnetic and Electric Circuit Design

High Power Factor Vernier PM Generators



Linear Motion Alternators


LMA Principle of Operation

PM-LMA with Coil Mover

Multipole LMA with Coil Plus Iron Mover

PM-Mover LMAs

Tubular Homopolar PM Mover Single-Coil LMA

Flux Reversal LMA with Mover PM Flux Concentration

PM-LMAs with Iron Mover

Flux Reversal PM-LMA Tubular Configuration

Control of PM-LMAs

Progressive-Motion LMAs for Maglevs with Active Guideway



About the Author

Ion Boldea is a professor of electrical engineering at the University Politehnica Timisoara, Romania. A life fellow of the Institute of Electrical and Electronics Engineers (IEEE), Professor Boldea has worked, published, lectured, and consulted extensively on the theory, design, and control of linear and rotary electric motors and generators for more than 40 years.

Subject Categories

BISAC Subject Codes/Headings:
TECHNOLOGY & ENGINEERING / Electronics / General
TECHNOLOGY & ENGINEERING / Power Resources / Electrical