Brushless Doubly-Fed Induction Machine with Feed-Forward Torque Compensation Control

Compared to Doubly-Fed Induction Machines (DFIMs), the dynamic and steady-state behavior of the Brushless Doubly-Fed Induction Machine (BDFIM) is more complicated. This fact is due to the coexistence of the undesirable asynchronous torques (disturbance torques) with the expected synchronous torque. In this paper, first, an analytical relationship between Control Machine (CM) currents, regarded as the system's input, and the total output torque, regarded as the system's output is derived. The relationship is expressed in both frequency and time domains to have a more clear vision of the BDFIM dynamic behavior. In the introduced equations, all types of torques that coexist in the BDFIM are considered. Then, by examining the obtained relationship, a motor drive with Feed-forward torque compensation is proposed that actively predicts the dynamic behavior of the BDFIM and attempts to eliminate undesirable dynamic responses. The dynamic behavior of the BDFIM with and without torque compensation method are compared for both open-loop and closed-loop torque control drive schemes, and the simulation results are presented. Field oriented control assumptions are made to obtain a suitable dynamic model for the BDFIM.