Ajay Singh & Anil Kumar Sahani 
Comparative Performance Analysis of Thyristor and IGBT Based Induction Motor Soft Starters [PDF ebook] 

Bachelor Thesis from the year 2012 in the subject Engineering – Power Engineering, grade: 10.0, Tribhuvan University (Institute of Engineering), course: Electrical Engineering, language: English, abstract: In this project, the performance of split-phase motor and three-phase induction motor drives for soft starting is evaluated. The pre systematically investigates and compares the characteristics of a variable voltage fed induction motor drive for two different types of soft starters; one based on IGBT and another based on Thyristor. The novelty of the work lies in the development of simple and flexible models for simulation purpose.

This project investigates the influence of the parameters of the machine and of the soft starter on the dynamics of the induction machine start. The situations may reproduce actual situations occurred in practice, for example, the variation of initial voltage Vi, modification of the start time and load value. In this project we have investigated the relation between Total Harmonic Distortion and Power Factor of the IGBT and Thyristor based soft starter. Using an already predefined fire angle characteristic the influence of the initial voltage was also evaluated.

Discussion of these results and conclusions as to the near-optimum types of profiles are delineated based on voltage and current profile fed to induction motor, starting times, and distortion in current with change in firing angle.