A simplified computational technique for the analysis of self-excited induction generators considering the core loss resistance

A simplified technique has been developed for accurately evaluating the steady-state performance of self-excited induction generator (SEIG). This proposed technique employs nodal analysis of the equivalent circuit of SEIG, taking the core loss resistance (Rm) also into consideration. This circuit has no voltage or current source and hence the net value of its complex nodal admittance becomes zero. The real and imaginary parts of this admittance, are then individually equated to zero and a closed-form expression for per unit (pu) speed (b), without involving the magnetizing reactance (Xm), is easily obtained in a few steps, for the specified pu frequency (a). Then, the expressions for Xm and Rm are also obtained. Subsequently, the complete performance of the SEIG is evaluated using the equivalent circuit. It is also shown that the proposed technique does not require lengthy complex derivations and it takes much less computational time, compared to the other commonly used methods for the analysis of SEIG. Test results, obtained on a three-phase, 4-pole, 3.7 kW, 230 V SEIG very closely agree with the computed values. The formulated technique is also slightly modified to make it applicable, if the performance evaluation is needed for a given pu speed.