Dual Control of Induction Generators for Tracing the Maximum Wind Energy

Abstract

ABSTRACT. All experts have expected the rapid exhaust of the conventional energy resources. Therefore, the utilization of wind energy is very important and finds nowadays great interest. The present paper aims at enhancing the performance of wind-driven induction generators at the different expected wind speeds through controlling both the stator and rotor sides. Controlling the stator side is done via a cycloconverter, while controlling the rotor side is done through adding resistances in the rotor circuit. This is achieved by connecting a bridge rectifier feeding a single resistance shunted by a dc chopper. This enables easier electronic control.The combined-controlled induction generator has been modelled at steady-state conditions using a frequency domain equivalent circuit. A new technique has been used to determine the stator cycloconverter frequency and the value of the added resistance in the rotor of the generator to track the maximum wind-energy point. Computer programs have been developed to compare the performance characteristics of the combined-controlled induction generator (CCIG) with the uncontrolled induction generator (UCIG). The comparison have revealed that the control of the induction generator through the stator cycloconverter and the rotor added resistances has enabled capturing more energy from the wind, and delivering more power to the network.