Modeling and Analysis with Induction Generators, 3rd Edition

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12

Simulation Tools for

Induction Generators

12.1 SCOPE OF THIS CHAPTER

Modern control of induction machines is a very challenging area of electrical engi-

neering, especially when control is based on detailed machine physical and math-

ematical models. The correct transient state representation of an induction generator

is a very complex matter because of the various electromagnetic and electromechan-

ical phenomena involved in a detailed equivalent circuit. This complexity is mostly

related to the dependence of the parameters on the frequency, transient mechanical

and electromagnetic states, and degree of accuracy of the approximations included

in the transient model.

Distributed stray inductances and capacitances in the machine windings and core,

imbricated variable magnetic path, and the exact core geometry representations are

some of the major difculties that make this one of the most complex elds in electri-

cal engineering. Nevertheless, the exact representation of so many details can lead

to important ndings in terms of reduction of electrical and mechanical stresses and

to an improvement of the electric eld distribution. Most of these details have been

resolved in daily practice and experience accumulated over the years. For these rea-

sons, many simplications are usually made throughout the kinds of practical repre-

sentations in Chapters 2 through 5. Industrial simulations of such scalar and vector

elds use nite elements and are beyond the scope of this book. For most practical

purposes, an extremely simplied model is sufcient to represent the main variations

of mechanical speed, frequency, torque, power, voltage, and current. Peaks of torque,

current, and voltage approximate the real ones encountered in practice, though elec-

tromagnetic interference and shaft oscillations are still not quite clear.

This chapter discusses the application of computer tools to the induction genera-

tor. The design of a small wind power plant and an appreciation of overall machine

behavior are proposed as applications for MATLAB

®

, PSpice

®

, the Pascal computer

language, the C computer language, Excel

®

, and PSIM

®

. Each of these computer tools

has features more or less suitable for applications in the eld of renewable sources

of energy that lead to precious increments of efciency and durability of equipment

under operating conditions. Furthermore, electrical and mechanical stresses can be

minimized with knowledge of the causes of torque, voltage, and current peaks or the

voltage and current intensity of switching surges.