Analytical and FE calculation of eddy-current losses in PM concentrated winding machines for wind turbines

Conference paper (2011)

Authors

A.K. Jassal Electrical Power Processing
H. Polinder Electrical Power Processing
D.J.P. Lahaye Numerical Analysis - EEMCS
Jan Abraham Ferreira Electrical Power Processing
Research Group
Electrical Power Processing
More Info
expand_more

Published Date

2011

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Research Group

Electrical Power Processing

Abstract

Permanent Magnet (PM) machines with
concentrated windings are cost effective, compact and
highly efficient. The application of such machines in large
Direct Drive (DD) wind turbines can be advantageous.
However, these machines have the problem of eddy
current losses in solid parts like magnets and rotor backiron.
Apart from cooling problems, these eddy current
losses might lead to de-magnetization of PMs because of
excessive heating. This paper presents an analytical model
for eddy current loss calculation in magnets and solid
back-iron of large wind turbines of MW rating. The
analytical model has been derived from 2-d magnetic
vector potential. The effects of simplifying assumptions
have been quantified by comparison with Finite Element
(FE) simulations. The analytical model over-estimates the
losses in magnets while losses in rotor back-iron are underestimated.
However, the total losses are accurate within
9% of FE calculation. The analytical model is very fast and
generic whereby this model can serve as a tool for design
optimization where eddy current loss is a criterion. A
design with 9 slots per 8 poles has acceptable eddy current
losses while in a 3 slots per 4 poles design losses are
unacceptable.