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.
Table of Contents
Chapter 1
INTRODUCTION
1.1 Project background
1.2 Literature review
Objectives
Methodology
Chapter 2
THEORETICAL BACKGROUND
2.1 Induction motor
2.1.1 Operating Principle
2.2 Starting of Induction motor
2.2.1 Direct-on-Line Starter
2.2.2 Star Delta Starter
2.2.3 Auto Transformer Starting Method
2.2.4 Rotor Resistance Starter
2.2.5 Solid State starting
2.3 Soft starters
2.4 Power electronics devices
2.4.1 Thyristor
2.4.2 Insulated Gate Bipolar Transistor (IGBT)
2.5 AC Voltage Controllers (AC Regulator)
2.5.1 Phase Control of Thyristor
2.6 Soft Starter with R-L Load
2.7 Performance parameter
2.8 Three Phase Soft Starter
2.9 Firing Circuits
2.9.1 Using ramp signal
2.9.2 Using cosine control:
2.10 Matlab/Simulink Basics
2.10.1 Matlab
2.10.2 Simulink
2.10.3 Lists of Blocks Used
2.10.4 Thyristor Characteristics
2.10.5 IGBT Characterisics
Chapter 3
SIMULATION STUDY
3.1 Thyristor with R-L load
3.2 Simulink model of IGBT with RL load
3.3 Comparative Performance
3.4 Simulink Model of Three Phase Induction Motor with Thyristor
CONCLUSION AND RECOMMENDATION
FUTURE IMPROVEMENT
REFERENCES
Project Goals and Thematic Focus
This project evaluates and compares the performance of Thyristor-based and IGBT-based soft starters for induction motors, specifically focusing on the dynamics during startup. The primary goal is to analyze the influence of system parameters on Total Harmonic Distortion (THD) and power factor under varying firing angles through simulation models developed in MATLAB/Simulink.
- Comparative analysis of Thyristor and IGBT soft starter performance.
- Evaluation of Total Harmonic Distortion (THD) and power factor in induction motor drives.
- Development of flexible MATLAB/Simulink simulation models for soft starters.
- Investigation of firing angle impacts on voltage and current profiles.
- Study of soft starter impact on reducing mechanical and electrical starting stress.
Excerpt from the Book
2.3 Soft starters
Soft starter using silicon-controlled rectifiers (SCRs) are now used extensively in the industry. This starting method essentially allows the control of the voltages applied to an induction motor and hence, control of its torque and the acceleration of a machine during its starting transient.
Electrical soft starters can use solid state devices to control the current flow and therefore the voltage applied to the motor. They can be connected in series with the line voltage applied to the motor, or can be connected inside the delta (Δ) loop of a delta-connected motor, controlling the voltage applied to each winding. Solid state soft starters can control one or more phases of the voltage applied to the induction motor with the best results achieved by three-phase control. Typically, the voltage is controlled by reverse-parallel-connected silicon-controlled rectifiers (thyristors), but in some circumstances with three-phase control, the control elements can be a reverse-parallel-connected SCR and diode.
The soft starters of switch all three phases are controlled can use the starting-up or shutting-down by means of voltage, current or torque control. At voltage control, is achieved a soft start-up, but it’s not generated any current or torque reaction. Appearance of soft starters produced a qualitative raise in starting, stopping or braking matter of induction motors with squirrel cage. These equipments are useless at starting-up of induction motors with phase wound rotor.
Summary of Chapters
Chapter 1: This chapter provides an overview of induction motor applications, the disadvantages of direct online starting, and the necessity of using soft starters to reduce starting currents and mechanical stress.
Chapter 2: This chapter establishes the theoretical framework, covering induction motor operation, various conventional and solid-state starting methods, and detailed descriptions of power electronics devices like Thyristors and IGBTs used in soft starters.
Chapter 3: This chapter presents the simulation study, detailing the modeling of soft starters for R-L loads and three-phase induction motors using MATLAB/Simulink, including comparative performance analysis regarding THD and power factor.
Keywords
Soft starter, Induction motor, Thyristor, IGBT, Total Harmonic Distortion, THD, Power Factor, MATLAB, Simulink, Phase control, Firing angle, Inrush current, Voltage regulator, Power electronics, Electrical drives
Frequently Asked Questions
What is the core focus of this research?
The work focuses on performing a comparative analysis of Thyristor and IGBT-based soft starters for induction motors to determine their efficiency in controlling starting transients.
What are the primary themes covered in this project?
The main themes include power electronics, induction motor dynamics, soft starting techniques, harmonic distortion analysis, and simulation-based performance modeling.
What is the central research objective?
The objective is to analyze and compare the performance of Thyristor and IGBT soft starters, specifically evaluating their impact on Total Harmonic Distortion (THD) and power factor.
Which methodology is utilized for the investigation?
The research employs a theoretical study of power electronics and induction motor drives, followed by the development, implementation, and analysis of firing circuits using MATLAB/Simulink.
What topics are discussed in the main section of the document?
The main section covers the theory of induction motors, soft starter configurations, operation of Thyristors and IGBTs, firing circuit design, and comprehensive simulation results for R-L loads and three-phase motors.
Which keywords best describe this study?
Key terms include soft starter, induction motor, Thyristor, IGBT, THD, power factor, MATLAB, and Simulink.
Why are IGBTs considered as an alternative to Thyristors in soft starters?
IGBTs are used because they are fast switching devices, which helps in addressing the low-frequency switching limitations associated with traditional Thyristors.
What does the simulation of the three-phase soft starter demonstrate?
The simulation demonstrates the use of a synchronized 6-pulse generator to control an induction motor load and shows the resulting phase currents and voltages at specific firing angles.
- Quote paper
- Ajay Singh (Author), Anil Kumar Sahani (Author), Mahanji Yadav (Author), 2012, Comparative Performance Analysis of Thyristor and IGBT Based Induction Motor Soft Starters, Munich, GRIN Verlag, https://www.grin.com/document/376772
