Abstract: A dynamic model in a D-Q synchronous rotating reference is presented for a self-excited induction generator (SEIG) that takes into account the stator and rotor iron core and stray load losses and dynamic saturation of magnetizing inductance. The new model deals with the same number of state-space differential equations as the conventional SEIG model by a modification the machine equivalent circuit. The modified equivalent circuit of SEIG can deal with all machine parameters without losing the accuracy of the calculation. This equivalent circuit will become an efficient tool for performing calculations as well as a suitable for vector control algorithm.