22-05-2013, 11:47 AM
High-order Models of a Doublefed Induction Generator
ABSTRACT
This chapter focuses on the modelling of a Double-fed Induction Generator (DFIG). DFIG
is nowadays one of the most currently researched wind turbine models and there is a
growing interest in understanding its behaviors. Therefore, it is of great importance to
compare different models and for instance to study how excluding transient phenomena
influences the simulation of the DFIG.
In other chapters, the modelling of the turbine as well as wind gust and other physical
phenomena are investigated and such phenomena are therefore excluded in this chapter.
Introduction
The high-order modelling of the DFIG is presented in this chapter. The chapter starts with
presenting a model on the most detailed level namely, an 8th-order differential model
including both rotor and stator electromagnetic transients, see Centeno (2000). With this,
the model covers fast transient phenomena that are not the situation when simulating DFIG
with a reduced-order, fundamental frequency model. The reduced-order model is used for
stationary studies, when it is assumed that all quantities are varying with fundamental
frequency, which is an appropriate simplification depending on which types of phenomena
the model should be valid for.
Comparisons
On the market it exists a number of different models for simulating DFIG. This chapter
makes comparisons between those models and when each of them can be used for which
environment, i.e., how valid they are depending on what should be studied and simplifications
that have been made for each of them. The chapter will shortly comment different
simulation methods, i.e., instantaneous value models and fundamental frequency models
respectively and necessary simplifications that have to be done when simulating with
fundamental frequency models.