Page 164 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

7 Small Wind Energy Systems

Marcelo Godoy Simões, Felix Alberto Farret,
and Frede Blaabjerg

CONTENTS

Abstract ..........................................................................................................................................151
7.1 Introduction ...........................................................................................................................151
7.2 Generator Selection for Small-Scale Wind Energy Systems ................................................152
7.3 Turbine Selection for Wind Energy ......................................................................................157
7.4 Self-Excited Induction Generators for Small Wind Energy Applications ............................159
7.5 Permanent Magnet Synchronous Generators for Small Wind Power Applications ..............162
7.6 Grid-Tied Small Wind Turbine Systems ...............................................................................168
7.7 Magnus Turbine–Based Wind Energy System .....................................................................171
7.8 Summary ...............................................................................................................................175
References ......................................................................................................................................175
Further Reading .............................................................................................................................176

ABSTRACT
This chapter intends to serve as a brief guide when someone is considering the use of wind energy
for small power applications. It is discussed that small wind energy systems act as the major energy
source for residential or commercial applications, or how to make it part of a microgrid as a distrib-
uted generator. In this way, sources and loads are connected in such a way to behave as a renew-
able dispatch center. With this regard, non-critical loads might be curtailed or shed during times of
energy shortfall or periods of high costs of energy production. If such a wind energy system is con-
nected to the public distributor, it can serve as a backup system, as a non-interruptible power supply
(with storage aggregation), provide low-voltage support, or give a clean surplus of energy trans-
ferred to the public network under economical and technological basis.
In this chapter, several factors are also considered when selecting a generator for a wind power
plant, including capacity of the AC system, types of loads, availability of spare parts, voltage regu-
lation, technical personal and cost. If several loads are likely inductive, such as phase-controlled
converters, motors, and fluorescent lights, it is evaluated that synchronous generators or induction
generators are an open-ended problem to be solved for the best choice.

7.1 INTRODUCTION
The application of small wind turbines for residential and commercial use depends on how a set of
distributed generation and loads using controllers can operate in a suitable way, because in addition
to variable demand, there is a random nature of the wind speed. Small wind turbines can supply
electrical power for stand-alone applications, or grid connected or even connected to microgrids,
that is, a group of generating sources and single or multiple end users for residential, industrial,
commercial, rural, or public applications.
Alternative sources of energy for microgrid systems may include wind turbines, small hydroplants,
photovoltaic panels, fuel cell stacks, geothermal energy, and small-scale renewable generators. In
general, either the management of energy storage or the control of a dummy load and a centralized

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