Wind turbine driven self-excited induction generator

Abstract Owing to increased emphasis on renewable resources, the development of suitable isolated power generators driven by energy sources such as wind, small hydro-electric, biogas, etc. have recently assumed greater significance. A capacitor self-excited induction generator has emerged as a suitable candidate of isolated power sources. The utilization of a three-phase squirrel cage induction motor as an autonomous self-excited induction generator is reviewed. Variations of electrical power due to changes in wind speed should be as small as possible. This is obtained by using an induction generator driven by a wind turbine. The system incorporates the use of turbine blade angle pitch control to control wind turbine speeds and shaft torque. A variable pitch turbine operates efficiently over a wider range of wind speeds. Self-excitation with capacitors at the stator terminals of the induction machine is well demonstrated experimentally on a d.c. motor-induction generator set. The parameters and the excitation requirement of the induction machine run in self-excited induction generator mode are determined. The effects of variations in prime mover speed, terminal capacitance and load power factor on the machine terminal voltage are studied.