Energy Harvesting for Autonomous Systems Book

Chapter 1 Introduction 1

1.1 Background and Motivation 1

1.2 Typical System Architecture 3

1.3 Intended Readership for This Book 4

Reference 5

Chapter 2 Wireless Devices and Sensor Networks 7

2.1 Introduction 7

2.2 Energy Requirements of Autonomous Devices 9

2.2.1 From Mobile Phones to MP3 Players 9

2.2.2 Radio Frequency Identification (RFID) 10

2.2.3 Wireless Sensor Networks 12

2.3 Enabling Technologies: Devices and Peripherals 19

2.3.1 Low-Power Microcontrollers and Transceivers 19

2.3.2 Sensors, Peripherals, and Interfaces 20

2.4 Wireless Communication 24

2.4.1 Communication Protocols and Power Requirements 24

2.4.2 Energy-Aware Communication Protocols 27

2.5 Energy-Awareness in Embedded Software 33

2.5.1 Operating Systems and Software Architectures 33

2.6 Alternative Nonrenewable Power Sources 35

2.6.1 Direct Transmission 35

2.7 Discussion 36

References 37

Chapter 3 Photovoltaic Energy Harvesting 45

3.1 Introduction 45

3.2 Background 46

3.2.1 Semiconductor Basics 46

3.3 Solar Cell Characteristics 49

3.4 Module Characteristics 50

3.5 Irradiance Standards 51

3.5.1 Outdoor Operation 51

3.5.2 Indoor Operation 54

3.6 Efficiency Losses 54

3.6.1 Intrinsic Losses 55

3.6.2 Extrinsic Losses 56

3.6.3 Module Losses 65

3.7 Device Technologies 65

3.7.1 Silicon Wafers 66

3.7.2 Single Crystal and Multicrystalline Devices 67

3.7.3 Amorphous Silicon 69

3.7.4 Thin Film Polycrystalline Silicon 70

3.7.5 Multijunction Silicon 71

3.7.6 Cadmium Telluride/Cadmium Sulphide 72

3.7.7 Copper Indium (Gallium) Disselenide 73

3.7.8 Single and Multijunction III-V Cells 74

3.7.9 Emergent Technologies 76

3.8 Photovoltaic Systems 79

3.8.1 Basic System 79

3.8.2 Charge Controllers 80

3.8.3 DC-DC Converters and Maximum Power Point Tracking 80

3.8.4 Miniaturization and Low-Power Systems 82

3.8.5 Device Technology 82

3.8.6 Systems Considerations 83

3.9 Summary 85

References 85

Chapter 4 Kinetic Energy Harvesting 91

4.1 Introduction 91

4.2 Kinetic Energy-Harvesting Applications 92

4.2.1 Human 92

4.2.2 Industrial 93

4.2.3 Transport 93

4.2.4 Structural 94

4.3 Inertial Generators 95

4.4 Transduction Mechanisms 97

4.4.1 Piezoelectric Generators 98

4.4.2 Electromagnetic Transduction 100

4.4.3 Electrostatic Generators 103

4.4.4 Transduction Damping Coefficients 105

4.4.5 Microscale Implementations 108

4.5 Operating Frequency Range 110

4.5.1 Frequency Tuning 111

4.5.2 Strategies to Broaden the Bandwidth 114

4.6 Rotary Generators 116

4.7 Example Devices 117

4.7.1 Human-Powered Harvesters 117

4.7.2 Conventional Generators for Industrial and Transport Applications 119

4.7.3 Microscale Generators 123

4.7.4 Tuneable Generators 126

4.8 Conclusions and Future Possibilities 128

4.8.1 Piezoelectric Generators 129

4.8.2 Electromagnetic Generators 129

4.8.3 Electrostatic Generators 130

4.8.4 Summary 130

Acknowledgments 131

References 131

Chapter 5 Thermoelectric Energy Harvesting 135

5.1 Introduction 135

5.2 Principles of Thermoelectric Devices 135

5.2.1 Thermoelectric Effects 136

5.2.2 Thermoelectric Devices 139

5.3 Influence of Materials, Contacts, and Geometry 142

5.3.1 Selection of Thermoelectric Materials 142

5.3.2 Thermal and Electrical Contacts 144

5.3.3 Geometry Optimization 146

5.3.4 Heat Exchangers 148

5.4 Existing and Future Capabilities 148

5.4.1 Low Power Systems 149

5.4.2 Waste Heat Recovery 151

5.4.3 Symbiotic Cogeneration System 153

5.4.4 Commercial Thermoelectric Module Suppliers 154

5.5 Summary 155

References 155

Chapter 6 Power Management Electronics 159

6.1 Introduction 159

6.1.1 Interface Circuit Impedance Matching 159

6.1.2 Energy Storage 161

6.1.3 Output Voltage Regulation 161

6.1.4 Overview 162

6.2 Interface Electronics for Kinetic Energy Harvesters 162

6.2.1 Electromagnetic Harvesters 164

6.2.2 Example of a Complete Power Electronics System for a Continually Rotating Energy Harvester 166

6.2.3 Piezoelectric Harvesters 182

6.2.4 Electrostatic Harvesters 188

6.3 Interface Circuits for Thermal and Solar Harvesters 197

6.3.1 Thermal 197

6.3.2 Power Electronics for Photovoltaics 201

6.4 Energy Storage Interfaces 204

6.4.1 Output Voltage Regulation 205

6.5 Future Outlook 206

6.6 Conclusions 207

References 207

Chapter 7 Energy Storage 211

7.1 Introduction 211

7.1.1 Battery Operating Principles 212

7.1.2 Electrochemical Capacitor Operating Principles 213

7.1.3 Comparison of Energy Storage Devices 214

7.2 Micropower Supply for Wireless Sensor Devices 215

7.2.1 Microenergy Storage Considerations 216

7.2.2 Materials Considerations for Microbatteries 217

7.2.3 Geometry and Processing Considerations for Microbatteries 219

7.3 Implementations of 2D Microbatteries 219

7.3.1 Thin Film Solid-State Microbatteries 220

7.3.2 Thick Film Microbatteries 222

7.3.3 Concluding Remarks for 2D Microbatteries 229

7.4 Three-Dimensional Microbatteries 230

7.4.1 3D Microbattery Architectures with a Discontinuous Element 232

7.4.2 3D Microbattery Architectures with Continuous Elements 237

7.4.3 Prospects for Three-Dimensional Microbattery Implementation 240

7.5 Electrochemical Microcapacitors 242

7.5.1 Electrochemical Capacitor Materials 242

7.5.2 Microcapacitor Prototypes 243

7.5.3 Conclusions and Prospects for Microcapacitors 246

7.6 Conclusion 247

References 247

Chapter 8 Case Study: Adaptive Energy-Aware Sensor Networks 253

8.1 Introduction 253

8.2 Requirements 254

8.3 Energy Harvesting Sensor Node Hardware Design 254

8.3.1 Node Core Design 254

8.3.2 Overview of Modular Design 255

8.3.3 Choice of Microprocessor 255

8.3.4 Energy Multiplexer Subsystem 256

8.3.5 Supercapacitor Energy Storage Module 257

8.3.6 Solar Energy-Harvesting Module 258

8.3.7 Vibration Energy-Harvesting Module 260

8.3.8 Thermal Energy-Harvesting Module 260

8.3.9 Wind Energy-Harvesting Module 261

8.3.10 Other Energy-Harvesting and Storage Modules 262

8.3.11 Plug-and-Play Capabilities 262

8.3.12 Sensor Module 264

8.3.13 Built-In Sensing Capabilities 265

8.3.14 Energy Efficient Hardware Design 265

8.4 Energy-Harvesting Sensor Node Demonstration Overview 267

8.5 Energy-Harvesting Sensor Node Software Design 267

8.5.1 Node Software 267

8.5.2 Intelligent Energy Management 269

8.5.3 Information Reported by the Energy-Harvesting Node 270

8.6 Energy-Aware, Energy-Harvesting Node Demonstration 271

8.6.1 Supporting Nodes for Demonstration 271

8.6.2 Energy Sources for Demonstration 271

8.6.3 Demonstration Sequence 272

8.7 Conclusions 275

References 276

Chapter 9 Concluding Remarks 277

About the Editors 279

About the Contributors 279

Index 283