Design And Implementation Of A Dc-Dc Boost Converter Using PID Controller Fed To A Dc Motor

ABSTRACT

DC-DC converters are electronic devices used to change DC electrical power efficiently from one voltage level to another. Operation of the switching devices causes the inherently nonlinear characteristic of the DC-DC converters including one known as the Boost converter.

This proposed study is based on the PID controlling direct current (DC) to the direct current boost converter feds DC motor which has 0.5hp and 220 V of DC voltage input on its characteristics. What is first formed is the boost converter mathematical model at the design stage. Secondly, a mathematical model of the DC motor is created so that the boost converter with the machine can be established and modeled at the Matlab Simulink. The PID controller is considered for arranging a pulse width modulation for a boost converter switch because the needed voltage is provided for a DC motor. After that, the PID controlling direct current (DC) to a direct current boost converter running the DC motor is implemented at the Matlab Simulink. In addition to that, the only constant source running the DC motor is simulated at the Matlab Simulink. The DC motor operated by the PID controlling converter that has a low input voltage is compared to the DC motor operated by the high constant DC voltage. A low voltage input converter controlling the DC motor has a high performance according to the high constant DC source running the DC motor.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• PROJECT SCOPE
• PROJECT LIMITATION
• APPLICATION OF THE PROJECT
• RESEARCH METHODOLOGY
• PROJECT ORGANIZATION

CHAPTER TWO

LITERATURE REVIEW

• INTRODUCTION
• DC TO DC CONVERTER
• OVERVIEW OF PID CONTROLLER
• OVERVIEW OF BOOST CONVERTER
• HISTORICAL BACKGROUND OF DC TO DC CONVERTERS
• APPLICATIONS OF DC TO DC CONVERTERS

CHAPTER THREE

METHODOLOGY

• SYSTEM BLOCK DIAGRAM
• SYSTEM OPERATION
• BOOST CONVERTER
• PID CONTROLLER
• MOTOR MODELLING

CHAPTER FOUR

RESULT ANALYSIS

4.1       SIMULATION RESULT

CHAPTER FIVE

• CONCLUSION
• REFERENCES

LIST OF SYMBOLS AND ABBREVIATIONS

C                        –        Capacitor

C_c                             –        The critical values capacitor

CCM                  –        Continuous Conduction Mode

D                        –        Duty Cycle

DC                     –        Direct Current

DCM                  –        Discontinuous Conduction Mode

E                        –        Error

F                               –        Frequency

FLC                   –        Fuzzy Logic Controller

Fs                       –        Frequency Switching

H∞                     –        H-infinity Controller

KD                     –        Derivative Gain

KI                      –        Integral Gain

KP                     –        Proportional Gain

KCL                   –        Kirchhoff Current Law

KVL                   –        Kirchhoff Voltage Law

L                        –        Inductor

MIMO                –        Multi-Input Multi-Output

MOSFET           –        Metal-Oxise- Semiconductor Field- Effect Transistor

PID                    –        Proportional Integral Derivative

PWM                 –        Pulse Width Modulation

R                        –        Resistor

CHAPTER ONE

1.0                                         INTRODUCTION

1.1                            BACKGROUND OF THE STUDY

DC motors are used in Industrial applications where wide range of speed control is required. The main advantage of DC motor is it presents the wide range of speed control both above and below the rated speed. DC series motors are used in electrical traction applications. DC-DC converters are widely used in switched-mode power supplies, adjustable speed drives, uninterruptible power supplies and many other applications to change the level of an input voltage to fulfill required operating conditions [Rubaai, 2004].

DC-DC converters are circuits which convert sources of DC from one voltage level to another by changing the duty cycle of the main switches in the circuits. Since DC-DC converters are nonlinear systems, they represent a big challenge for control design. Since classical control methods are designed at one nominal operating point, they are not able to respond satisfactorily to operating point variations and load disturbance. They often fail to perform satisfactorily under large parameter or load variations [Dhali, 2012].

The DC-DC converter has some functions, from this functions it convert a DC input voltage v_s into a DC output voltage v_o as well as regulate the DC output voltage against load and line variations, reduce the AC voltage ripple on the DC output voltage below the required level, and protect the supplied system and the input source from electromagnetic interference [Rubaai, 2004].

The DC-DC converters can have two distinct modes of operation: Continuous conduction mode (CCM) and discontinuous conduction mode (DCM). In practice, a converter may operate in both modes, which have significantly different characteristics. However, for this project only considers the DC-DC converters operated in CCM. CCM is for efficient power conversion and DCM for low power or stand-by operation [Elbaset, 2008].

The DC-DC converter is considered as the heart of the power supply, thus it will affect the overall performance of the power supply system. The converter accepts DC and produces a controlled DC output.

Operation of the switching devices causes the inherently nonlinear characteristic of the DC-DC converters. Due to this unwanted nonlinear characteristics, the converters requires a controller with a high degree of dynamic response. Pulse Width Modulation (PWM) is the most frequently consider method among the various switching control method [Jamali, 2012]. In DC-DC voltage regulators, it is important to supply a constant output voltage, regardless of disturbances on the input voltage.

There are many control techniques used for control in DC-DC converter, for example: PID Controller, Fuzzy logic controller and H-infinity Controller (H∞), but in this study we are using PID Controller techniques: PID stands for proportional, integral, derivative are one of the most popular feedback controller widely use in processing industry. It is easy to understand the algorithm to produce excellent control performance [Hartmut, 1994].

1.2                                                                              PROBLEM STATEMENT

DC-DC converter consists of power semiconductor devices which are operated as electronic switches. Operation of the switching devices causes the inherently nonlinear characteristic of the DC-DC converters including one known as the boost converter. Development of the DC-DC converter requires PWM signals with a high switching frequency to avoid more of output voltage ripple, overshoot and decrease the setting time. This converter requires a controller with a high degree of dynamic response. Proportional-Integral- Differential (PID) controllers have been usually applied to the converters because of their simplicity.

1.3                                                                           AIM AND OBJECTIVE OF THE PROJECT

The main aim of this work is to study the PID Controller control techniques used for control in DC-DC converter that is used in control of a dc motor speed. The objectives of this project are:

1. To simulation of boost converter fed DC motor using PID techniques
2. To model and analyze of the DC-DC Boost converter

• To design a PID controller to control the switching of DC-DC Boost

1. To analyze the voltage output for DC-DC Boost converter between closed

1.4                               PROJECT SCOPE

This study explains the simulation of boost converter fed DC motor. The output voltage of the boost converter is maintained constant regardless of slight change in input voltage. Using PID controller output voltage of the boost converter is kept constant. The output voltage of boost converter is fed to the DC motor. Hence speed of DC motor is controlled and kept constant for various applications.

1.5                           PROJECT LIMITATION

Consequently, this converter requires a controller with a high degree of dynamic response. Proportional-Integral- Differential (PID) controllers have been usually applied to the converters because of their simplicity. However, the main drawback of PID controller is unable to adapt and approach the best performance when applied to nonlinear system. It will suffer from dynamic response, produces overshoot, longer rise time and settling time which in turn will influence the output voltage regulation of the Boost converter.

1.6                                         APPLICATION OF THE PROJECT

DC motors are used in Industrial applications where wide range of speed control is required. The main advantages of DC motor are it presents the wide range of speed control both above and below the rated speed. DC series motors are used in electrical traction applications. These motors have high starting torque. There for used in electrical trains and cranes.

In order to maintain constant speed of dc motor the armature voltage is kept constant. For this DC-DC converter is used. The armature voltage is kept constant by using PID controller.

1.7                                             RESEARCH METHODOLOGY

In the course of carrying this study, numerous sources were used which most of them are by visiting libraries, consulting journal and news papers and online research which Google was the major source that was used.

1.8                                     PROJECT ORGANIZATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.