Synchronous drive performance of brushless doubly-fed motors

This paper presents studies of the steady-state performance of the brushless doubly-fed machine for adjustable-speed drive applications. The equivalent circuit and basic performance equations are presented followed by a proven technique for the solution of the least restrained form of the equations. Model predictions and experimental results are given. The studies show that the machine acts like both a synchronous motor, with power factor adjustable by control winding excitation, and a slip-ring induction machine with slip power recovery and a low converter rating. The model is suitable for development of control schemes and performance index optimization.>