Brushless Doubly-Fed Induction Machines: Magnetic field modelling

The brushless DFIM is a complex machine type. Though never commercially exploited, it has a great potential as generator system in large-scale wind turbines. This paper develops an analytical magnetic field model for the brushless DFIM. Since the brushless DFIM rotor construction has a rich space harmonic spectrum, attention is paid to the effects of winding space-harmonics. The developed model is validated by FE calculations. With use of the developed model, the brushless DFIM operating principles are considered from the point of view of the magnetic field.