ANALYSIS OF A STAND-ALONE INDUCTION GENERATOR WITH ROTOR FLUX ORIENTED CONTROL

Abstract

In this dissertation a detailed mathematical modelling of an induction generator in isolated mode has been presented. Reactive power requirement of generator are met by a static reactive power compensator of voltage source inverter (VS I) type, where the control of the compensator is achieved using rotor flux oriented control. Simulated results were also recorded for the induction generator with its reactive power requirements supplied through capacitor bank. The behaviour of induction generator was recorded for the following mode of operation: Case - I: Sudden removal and reapplication after a time delay of a purely resistive load. Case - IL: Sudden removal and reapplication after a time delay of a inductive load (0.8 p.f. lagging load). Case - III: When a capacitance of a sufficient value is connected across the terminals of a self-excited induction generator, the voltage starts building up due to the residual magnetism present in the machine. The initiation of the self-excitation process has been studied. Case - IV : The self-excited stand alone induction generator looses excitation when a sudden short circuit (or heavy load) takes place at its terminals. This is one of the advantages of self-excited stand alone induction generators. The phenomenon has also been studied by plotting the variation of terminal voltage with respect to time. Case - V: No load self-excitation process, step load application and speed variation in the base speed region has been studied under rotor flux orientation control.