2-AXIS MODEL DEVELOPMENT OF CAGE-ROTOR BRUSHLESS DOUBLY-FED MACHINES

This paper presents a two-axis (d-q) model of cage-rotor Brushless Doubly-Fed Machines (BDFM) which is suitable for machine and BDFM drive system dynamics studies. The novel modeling technique shown in the paper enables the two-axis model to be derived from a very detailed model recently developed for investigation of design aspects of the machine. Unlike the conventional approaches to self-cascaded machine analysis, the new method permits not only analysis of the machine characteristics in both dynamic and steady state conditions, but also facilitates machine and drive system design by directly correlating machine performance with machine structure and parameters. The proposed approach allows the machine parameters to be calculated from machine geometry and developed into the d-q model parameters. In the companion paper, simulation results are presented and compared with test data to show the validity of the two-axis model.