An Approach to Improve the Performance of Three-phase Self-excited Induction Generator Feeding an Induction Motor Load using Hilbert Transform and Coordinate Rotation Digital Computer

Abstract

Self-excited induction generators are mostly preferred in isolated areas to feed three-phase squirrel-cage induction motors for agricultural purposes to pump water. When the induction motor is connected to the self-excited induction generator without any voltage and frequency controller, it causes severe transients in the electrical and mechanical variables of the generator. Due to the large starting current requirement of the induction motor, there is a collapse of the terminal voltage of the generator; thus, the self-excited induction generator requires a voltage and frequency controller to run an induction motor safely in remote and isolated areas. This article presents a voltage and frequency control scheme for the self-excited induction generator to run an induction motor using a generalized impedance controller. The novelty of this work is to estimate the peak terminal voltage and frequency of the self-excited induction generator using Hilbert transform and the Coordinate Rotation Digital Computeralgorithm. The proposed scheme requires only one voltage sensor, and its output voltage is processed to estimate peak voltage and control the modulation index of the generalized impedance controller to control the self-excited induction generator voltage and frequency and run the induction motor without causing any disturbance.