Induction Machines - 1. Introduction

This simulator test bench was designed to foster user interaction and to provide a wide range of experiments.

The basic teaching approach for electric machines consists in using both lectures and practical exercises to teach the fundamentals, operating modes and characteristics, modelling on steady state and transient period, and finally, industrial applications.

Laboratory exercises are an essential complement to theory.
They allow students to experience test implementation of real devices that consider the limits imposed by the protection systems.
Furthermore, the characterization tests of electrical machine models at reduced power are an essential goal for lab tests performed as a part of training.

The user can take advantage of this virtual simulator to understand the typical sizing methods for electrical networks and industrial applications using electric machine models with several levels of complexity.
These models are integrated into powerful simulation tools that operate in real-time or offline.
The main problem, often overlooked in training programs, is identifying model parameters for real devices.
When designing or sizing a specific installation, the simulation can only be efficient if the model of the implemented system represents real behavior.

The five basic induction machine tests included in this manual were developed with these problems in mind and allow users to learn:

• Induction machine operating modes, specifically for the wound rotor machine during phase-shifting transformer mode and frequency converter mode.
• Identifying steady state model parameters for the induction machine using standard reduced power tests.
• Induction machine commissioning, start-up, and speed regulation procedures (and its coupled DC machine).
• Validation of the model parameters identified by direct comparison of the measured characteristics with theoretical characteristics calculated by models.

The five exercises that can be run on the virtual test bench developed by OPAL-RT are:

Exercise 1: Wound rotor induction machine operating in a phase-shifting transformer and frequency converter.
Exercise 2: Test identification of steady state induction machine and induction motor without load.
Exercise 3: Induction motor speed regulation using fixed frequency voltage variations.
Exercise 4: Wound rotor induction motor speed regulation using rotor resistance.
Exercise 5: Induction motor speed regulation using a variable voltage and frequency inverter.

Detailed protocols are available in Sections 4 to 8 of this document.