One of the main disadvantage of the squirrel cage self-excited induction generator is the variation of both voltage and frequency with the speed variations. The amplitude and frequency of the output voltage of a self-excited induction generator may be adjusted across a wide speed range by using a slip-ring induction machine. In this, paper a study on using a self-excited slip-ring induction generator (SEWRIG) to generate an output with constant voltage and frequency by controlling effective rotor resistance. The steady state characteristics are obtained by analyzing the normalized equivalent circuit of the self-excited induction generator. The study revealed that, for a given stator load impedance, as the speed is varied both the frequency and the voltage can be maintained constant, without changing the excitation capacitance. A closed-loop control scheme for the constant voltage and frequency operation of (SEWRIG) using chopper-controlled rotor resistance is also discussed. With a properly tuned proportional-plus-integral (PI) controller using Particle Swarm Optimization (PSO) algorithm,
satisfactory dynamic performance of the (SEWRIG) is obtained. Experiments performed on a 370 W laboratory machine to confirm the feasibility of the proposed method.