| Abstract |
The variable speed, variable frequency wind energy conversion schemes are becoming popular in the recent years. This type of scheme uses a squirrel cage Induction Generator driven by a vertical axis wind turbine. The Induction Generator is self excited by fixed shunt capacitors. The inherent poor voltage and frequency regulation of the Induction Generator are overcome by the AC/DC/AC asychronous link where the a.c. power delivered by the generator is converted to d.c. and fed to the a.c. utility system through an inverter. It is possible to maintain a constant voltage at the load and by controlling the firing angle of the rectifier bridge. The complete system consists of an Induction Motor with suitable fixed shunt capacitors, driven by a d.c. motor, and the controlled three phase rectifier with a load. A control strategy is developed to maintain the voltage at the load and constant, by controlling the firing angle of the rectifier bridge for a wide range of speed and load conditions. The proposed controller has been designed, implemented and successfully tested using an Intel 8085 microcomputer system. |
