Determination of minimum and maximum capacitances of a self-regulated self-excited single-phase induction generator using a three-phase winding

This paper presents a simple and direct approach based on eigenvalue and eigenvalue sensitivity method to predict both minimum and maximum values of capacitance required for self-excitation of a single-phase induction generator using a three-phase winding. The generator consists of a three-phase star connected induction machine and three capacitors connected in series and parallel with a single-phase resistive load. The voltage regulation of this generator is very small due to the effect of the series capacitors. Traditionally, the minimum and maximum capacitances required for a self-excited induction generator (SEIG) were solved by a high order non-linear polynomial equation based on a per phase equivalent circuit model. But, the advantage of this proposed method is its simplicity, since the complicated solution procedure of the high order polynomial is avoided. The dynamic model of the three-phase SEIG is developed, based on stationary reference frame d-q axes theory, and the excitation capacitorspsila equations are described by three-phase abc model, assuming constant speed prime-mover. Eigenvalue sensitivity method is used to determine both the minimum and maximum values of the capacitance for self-excitation of the studied SEIG.