Steady-state analysis of an isolated self-excited induction generator driven by regulated and unregulated turbine

This paper examines the steady-state analysis and performance of an isolated three-phase self-excited induction generator (SEIG) driven by regulated and unregulated turbine. For the case of a regulated turbine the equivalent circuit is solved with speed as a constant parameter, while for the unregulated turbine, the speed is considered as a variable which depends on the shaft torque according to the turbine characteristics. The no-load speed is considered as a constant independent parameter, which depends on wind speed which is assumed constant in this analysis. The steady-state equivalent circuit is solved using the node-admittance method, and the shaft torque is expressed in terms of the rotor current. The Newton-Raphson method is used to solve the system nonlinear equations. For the present investigation, a linear speed-torque characteristic is considered, but the method of analysis applies equally well to nonlinear characteristics. Experimental investigations on a 1-kW three-phase induction generator driven by a separately excited de shunt motor have confirmed the accuracy of the proposed method of analysis.