COMPUTATION OF WINDING INDUCTANCES OF PERMANENT-MAGNET BRUSHLESS DC MOTORS WITH DAMPER WINDINGS BY ENERGY PERTURBATION

A method for the calculation of motor winding inductances is presented in which damping effects due to metallic retainment sleeves and intentionally introduced damper bar (amortisseur) windings are included. The inductance computation method makes use of the combined energy perturbation concept and finite-element field solutions. These parameters are necessary for the prediction of the dynamic performance of such motors with rotor damping. This modeling approach accounts for all saliency effects, and is entirely carried out in the natural abc frame of reference. Thus, it facilitates the process of integration of the modeling of the motor and its associated power electronics. The approach is most effective in the design of damper bar systems for enhancement of the performance of such motors, as demonstrated in the application of this approach to a 15-hp, 120-V, 6-pole, samarium-cobalt, permanent-magnet brushless DC motor.