A General Model for Describing the Performance of Brushless Doubly-Fed Induction Machines

Abstract

This paper presents a generalized model, by which the dynamic and steady-state behaviour of the Brushless Doubly-Fed Induction Machine (BDFIM) can be precisely predicted. The investigated doubly-fed machine has two sets of three-phase stator windings with different pole numbers. The rotor is a squirrel-cage type with a simple modification in order to support the two air-gap rotating fields that are produced by the stator windings and have different pole numbers. The machine model is derived in the qdo-axis variables. The qdoaxes are attached to rotor and hence, it rotates at the rotor speed ( m ). The electromagnetic torque expression is also obtained based on the presented model. The winding function method is applied as a convenient approach that can be used for machine-winding inductances calculations. Sample case studies are introduced to examine the performance of the proposed model in both steady-state and dynamic conditions.