Steady state analysis of brushless doubly fed induction machine taking core loss into account

Brushless doubly fed induction machines show promising results for wind power applications. Due to their poor rotor magnetic coupling and relatively high value of slip, core loss is an important factor which affects the steady state and dynamic performance. The core loss effect on performance of brushless doubly fed induction machines has not been extensively studied in the literature. In this paper, a steady state equivalent circuit taking core loss into account is introduced. Simple relationships are derived which show that the brushless doubly-fed induction machine is similar to the cascaded doubly-fed induction machine in terms of core loss. The energy conservation principle is applied to derive relations for steady state torque of the machine when core loss exists. The steady state characteristics of the machine taking core loss into account are simulated and compared with the model without core loss.