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Mathematical models of brushless doubly-fed induction machines

Brushless doubly-fed machines (BDFM) are used in electric drives and variable speed generators. There is a large number of BDFM designs and models used for various purposes and controlled by various methods. This article provides an overview of the mathematical models used by BDFM. An analysis of the models is made, their main properties and characteristics are indicated, and recommendations are made regarding their usage. Original mathematical models are proposed for the two main types of BDFM - single-frame stator windings and isolated ones. The proposed models have the smallest dimensions and contain the minimum number of variable coefficients.