Dynamic modeling of brushless doubly-fed machines

A mathematical model that has the necessary flexibility to investigate design alternatives of the brushless doubly fed machine (BDFM) is developed. The model development starts from a consideration of the basic stator coils and the basic nested loops that constitute the rotor cage. The simple time-domain interactions that occur between the basic machine components are developed into the performance equations of the BDFM by application of the appropriate connection matrices. These matrices represent the internal connection of stator coil groups and the final connections to two independent three-phase supplies of different frequency and voltage. The resulting model of electrical performance and the associated torque equations are suitable for solution as a set of state variable equations. This makes possible the simulation of the system interactions that occur between the machine, its power converter, and the utility supply in any combination of monitoring or generating, synchronous or asynchronous modes that is possible with the BDFM.<>