Bidirectional Converter For Renewable Energy Application.

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

FACULTY OF ELECTRICAL ENGINEERING

LAPORAN PROJEK SARJANA MUDA

BIDIRECTIONAL CONVERTER FOR

RENEWABLE ENERGY APPLICANTION

CHONG MAN YUEN

“I hereby declare that I have read through this report entitle “Bidirectional converter for

renewable energy application” and found that it has comply the partial fulfillment for awarding the degree of Bachelor of Electrical Engineering (Industrial Power)”

Signature : ...

Supervisor’s Name : ...

Date : ...

BIDIRECTIONAL CONVERTER FOR RENEWABLE ENERGY APPLICATION

CHONG MAN YUEN

A report submitted in partial fulfillment of the requirements for the degree of Electrical Engineering(Industrial Power)

Faculty of Electrical Engineering

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

I declare that this report entitle “Bidirectional converter for renewable energy application”

is the result of my own research except as cited in the references. The report has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.

Signature : ...

Special dedicated to my beloved parent and family

For my supervisor, Mr. Azhan Bin Ab. Rahman Universiti Teknikal Malaysia Melaka

And lastly to my beloved friends and who encouraged, guided and inspired me throughout

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ACKNOWLEDGEMENT

First of all, I would like to express my deepest thankful and gratitude to my family which give me fully support during my deepest concentrations. In particular, I wish to

express my sincere appreciation to my main project supervisor, En. Azhan Bin Ab. Rahman for encouragement, guidance critics and friendship. Without his continued support and interest, this project would not have been same as presented here.

Secondly, it is difficult to name all the people who directly and indirectly help me in this project; an idea here and there may have appeared insignificant at the time but may have had a significant casual effect. In addition, deeply acknowledge who involve directly and indirectly for their never ending encouragement, moral support and patient during the

duration of final year project. For all your advice and encouragement, this thesis is gratefully dedicated to my family and my friends. Thank you very much for your

continuous support toward this the publication of this thesis.

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ABSTRACT

The Project is aimed to design a battery system that consists of a bidirectional converter for renewable energy application. In order to determine the most applicable

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ABSTRAK

Projek ini adalah bermatlamat untuk merekabentuk satu sistem bateri yang mengandungi sebuah penukar dwiarah untuk mengaplikasikan penggunaan tenaga boleh

viii 2.2 Switch-mode power supply (SMPS) 6 2.2.1 Rectifier 6 2.2.2 Smoothing 9

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CHAPTER TITLE PAGE

2.3.4 Diode 18 2.3.5 Insulated gate bipolar transistor (IGBT) 19 2.4 Feedback control system 20 3.3.3 Bidirectional converter circuit 29 3.3.3.1 Circuit one 29

4 SIMULATION RESULT AND DISCUSSION 37

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4.5 Summary of simulation result 45 4.5 Performance test for circuit four 47

4.5.1 Test one 47 4.5.2 Test two 49

5 Conclusion 51

5.1 Conclusion 51

5.2 Recommendation 52 5.3 Contribution 52

CHAPTER TITLE PAGE

REFERENCES 53

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4.7 Capacitor voltage and battery current of circuit three 46 4.8 Capacitor voltage and battery current of circuit four 46 4.9 Waveform of Vs, Is,Vcap, Icap, Vbat, Ibat and Icon 48

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LIST OF FIGURES

FIGURE TITLE PAGE

2.1 Cost of generating electricity in UK[3] 4 2.2 Wind power technology development[7] 5 2.3 Conventional configuration for renewable 6

energy power generation[4]

2.4 Half-wave rectifier and waveform[15] 7 2.5 Half-wave rectifier with transformer-coupled 7

input voltage[15]

2.6 Half-wave rectifier operation and waveform[15] 7

2.7 Full wave rectifier and waveform[15] 8 2.8 Center-tapped full wave rectifier[15] 8

2.9 Full-wave rectifier operation and waveform[15] 9 2.10 Waveform after smoothing[4] 10 2.11 Bridge inverter configuration[6] 11 2.12 Renewable energy generation configuration with 11

back-up supply and bidirectional converter

2.13 Current from line flow into battery while 12 excessive of power available

2.14 Current flow out from battery and supply to load 12

while supply is low

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FIGURE TITLE PAGE

2.19 Buck-boost circuit diagram[16] 15 2.20 Buck-boost converter waveform in continuous 16

mode[17]

2.21 Bidirectional converter circuit diagram[8] 17 2.22 Example and circuit symbol of diode[11] 18

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LIST OF ABBREVATIONS

V - Voltage I - Current

A - Ampere

IEEE - Institute of Electrical and Electronic Engineers SMPS - Switch-mode power supply

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LIST OF APPENDICES

APPENDIX TITLE PAGE

A Project Planning 56 B A new topology of a battery energy storage system 58 C Efficient, High-Temperature Bidirectional Dc/Dc

Converter for Plug-in-Hybrid Electric Vehicle(PHEV) 65 using SiC Devices

D Analysis and Control of Bidirectional DC/DC 73 Converter for PEM Fuel Cell Applications

E Parallel Bidirectional DC/DC Converter Topology 81

for Energy Storage Systems in Wind Applications

CHAPTER 1

INTRODUCTION

1.1 Problem Statement

Although switch-mode power supply (SMPS) is commonly use in renewable energy generation industry but renewable energy generation supply is inconsistent due to renewable energy relies on the weather for its source of power. To solve this problem, battery and bidirectional converter is needed to perform bidirectional power flow. Besides that, Bidirectional converter that use in the renewable energy generation industrial is

complex and expensive.

This project is focused on the design of bidirectional converter. The Bidirectional converter to be designed has to meet the requirement of:

1. Enable to perform basic bidirectional power flow 2. Simple design

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1.2 Project Objective

The objectives of this project are:

1. To design a battery system which consist of a bidirectional converter for a renewable energy application.

2. The battery is supposed to be energized when there is excessive supply of power available.

3. The battery is also supposed to release its energy when supply of power is low.

1.3 Project Scope

The target of this project is on the design of bidirectional converter. Simulation will be performed only on the four chosen bidirectional converter circuits by using PSCAD. From the simulation result, the battery is supposed to be energized when there is excessive

supply of power available. The battery is also supposed to release its energy when supply of power is low. Besides, the four chosen bidirectional converter circuits have to meet three

CHAPTER 2

LITERATURE REVIEW

2.1 Renewable energy

Nowadays, many energy sources include oil, nature gas, and coal that are extremely limited in supply and they will exhaust soon. So in an effort to find alternative forms of energy, the world has turned to renewable energy sources as the solution.

Renewable energy is the energy generated from natural sources such as sunlight,

wind, tides and geothermal heat which are naturally replenished. We can capture some of this energy and put it to use in our homes and businesses with the help of special collectors.

As long as sunlight, water and wind continue to flow and trees and other plants continue to grow, we have access to a ready of supply of energy.

The most common advantage with the use of renewable energy is that they are renewable and cannot be depleted. Besides that, Renewable energy is produces little or no waste products such as carbon dioxide or other chemical pollutants, so they don’t pollute environment and don’t contribute to global warming or greenhouse effect. Since renewable energy is natural, the cost of operations is reduced. By then, renewable energy facilities

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in that area.[1]

It is easy to recognize the environmental advantages of utilizing the alternative and renewable forms of energy but we must also be aware of the disadvantages. One of the disadvantages with renewable energy is difficult to generate the quantities of electricity that are as large as those produced by traditional fossil fuel generators. This may mean that we need to reduce the amount of energy we use or simply build more energy facilities.[2]

Another disadvantage of renewable energy sources is the reliability of supply. Renewable energy often relies on the weather for its source of power, for example, hydro generators need rain to fill dams to supply flowing water, Wind turbines need wind to turn the blades and solar collectors need clear skies and sunshine to collect heat and make electricity. When unsuitable weather condition happens, renewable energy plant cannot supply enough energy to us. This mean renewable energy is unpredictable and inconsistent.[1] Besides that, the current cost of renewable energy technology is also far in excess of traditional fossil fuel generation. This is because it is a new technology and as such has extremely

large capital cost.[2]

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Figure 2.1 shows the cost of generating electricity with no cost of CO2 emissions included in UK. The first six elements is traditional generation and last four is renewable energy generation. From here show that cost of generating electricity by renewable energy are more expensive than traditional generation.[3]

Renewable energy generation will improve because of power electronics. Once renewable energy generation establish and stable, it will much cheaper if compare to

traditional generation.[7]

Figure 2.2: Wind power technology development.[7]

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2.2 Switch-mode power supply (SMPS)

Figure 2.3 : Conventional configuration for renewable energy power generation[4]

Figure 2.3 shows conventional configuration for renewable energy power generation. First, renewable energy output pass rectifier and convert to DC output. After that, DC output from rectifier will pass a capacitor to smooth the ripple of DC output. Next,

the DC output will pass inverter and convert to AC output. Last, AC output from inverter will go in to grid line and supply to consumer.

2.2.1 Rectifier

A basic rectifier is a circuit that converts AC input power to DC output power. The input supply may be a single phase or a multi-phase supply. The output is DC voltage and

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In practice, the half-wave rectifier is used most often in low-power applications because the average current in the supply will not be zero. This may cause problems in transformer performance. While practical applications of half wave rectifier are limited, the analysis is important because it will enable us to understand more complicated circuits such as full wave-and three-phase rectifiers.

Figure 2.4: Half-wave rectifier and waveform[15]

Figure 2.5: Half-wave rectifier with transformer-coupled input voltage[15]

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Figure 2.4 shows the half-wave rectifier and waveform. Next, Figure 2.5 shows the half-wave rectifier with transformer-coupled input voltage. Last, Figure 2.6 shows half-wave rectifier operation and waveform. Like half-wave, the objective of a full-wave rectifier is to produce a voltage or current which is purely DC or has some specified dc component. While the purpose of the full wave rectifier is basically the same as that of the half-wave rectifiers have some fundamental advantages. The average current in the ac source is zero in the full-wave rectifier, thus avoiding problems associated with nonzero

average source currents. The average DC output voltage is higher than half-wave. The output of the full-wave is inherently less ripple that the half-wave rectifier.[7]

Figure 2.7: Full wave rectifier and waveform[15]