Title Details

About the Volume Editors XVII

List of Contributors XIX

1 Introduction to Micro Energy Harvesting 1
Danick Briand, Eric Yeatman, and Shad Roundy

1.1 Introduction to the Topic 1

1.2 Current Status and Trends 3

1.3 Book Content and Structure 4

2 Fundamentals of Mechanics and Dynamics 7
Helios Vocca and Luca Gammaitoni

2.1 Introduction 7

2.2 Strategies for Micro Vibration Energy Harvesting 8

2.2.1 Piezoelectric 9

2.2.2 Electromagnetic 10

2.2.3 Electrostatic 11

2.2.4 From Macro to Micro to Nano 11

2.3 Dynamical Models for Vibration Energy Harvesters 12

2.3.1 Stochastic Character of Ambient Vibrations 14

2.3.2 Linear Case 1: Piezoelectric Cantilever Generator 14

2.3.3 Linear Case 2: Electromagnetic Generator 15

2.3.4 Transfer Function 15

2.4 Beyond Linear Micro-Vibration Harvesting 16

2.4.1 Frequency Tuning 16

2.4.2 Multimodal Harvesting 17

2.4.3 Up-Conversion Techniques 17

2.5 Nonlinear Micro-Vibration Energy Harvesting 18

2.5.1 Bistable Oscillators: Cantilever 19

2.5.2 Bistable Oscillators: Buckled Beam 21

2.5.3 Monostable Oscillators 23

2.6 Conclusions 24

Acknowledgments 24

References 24

3 Electromechanical Transducers 27
Adrien Badel, Fabien Formosa, andMickaël Lallart

3.1 Introduction 27

3.2 Electromagnetic Transducers 27

3.2.1 Basic Principle 27

3.2.1.1 Induced Voltage 28

3.2.1.2 Self-Induction 28

3.2.1.3 Mechanical Aspect 29

3.2.2 Typical Architectures 30

3.2.2.1 Case Study 30

3.2.2.2 General Case 33

3.2.3 Energy Extraction Cycle 33

3.2.3.1 Resistive Cycle 34

3.2.3.2 Self-Inductance Cancelation 34

3.2.3.3 Cycle with Rectification 35

3.2.3.4 Active Cycle 36

3.2.4 Figures of Merit and Limitations 36

3.3 Piezoelectric Transducers 37

3.3.1 Basic Principles and Constitutive Equations 37

3.3.1.1 Physical Origin of Piezoelectricity in Ceramics and Crystals 37

3.3.1.2 Constitutive Equations 38

3.3.2 Typical Architectures for Energy Harvesting 39

3.3.2.1 Modeling 39

3.3.2.2 Application to Typical Configurations 40

3.3.3 Energy Extraction Cycles 41

3.3.3.1 Resistive Cycles 41

3.3.3.2 Cycles with Rectification 43

3.3.3.3 Active Cycles 43

3.3.3.4 Comparison 43

3.3.4 Maximal Power Density and Figure of Merit 44

3.4 Electrostatic Transducers 45

3.4.1 Basic Principles 45

3.4.1.1 Gauss’s Law 45

3.4.1.2 Capacitance C0 45

3.4.1.3 Electric Potential 46

3.4.1.4 Energy 46

3.4.1.5 Force 47

3.4.2 Design Parameters for a Capacitor 47

3.4.2.1 Architecture 47

3.4.2.2 Dielectric 48

3.4.3 Energy Extraction Cycles 48

3.4.3.1 Charge-Constrained Cycle 49

3.4.3.2 Voltage-Constrained Cycle 50

3.4.3.3 Electret Cycle 51

3.4.4 Limits 51

3.4.4.1 Parasitic Capacitors 51

3.4.4.2 Breakdown Voltage 53

3.4.4.3 Pull-In Force 53

3.5 Other Electromechanical Transduction Principles 53

3.5.1 Electrostrictive Materials 53

3.5.1.1 Physical Origin and Constitutive Equations 53

3.5.1.2 Energy Harvesting Strategies 54

3.5.2 Magnetostrictive Materials 55

3.5.2.1 Physical Origin 55

3.5.2.2 Constitutive Equations 56

3.6 Effect of the Vibration Energy Harvester Mechanical Structure 56

3.7 Summary 58

References 59

4 Thermal Fundamentals 61
Mathieu Francoeur

4.1 Introduction 61

4.2 Fundamentals of Thermoelectric Power Generation 62

4.2.1 Overview of Nanoscale Heat Conduction and the Seebeck Effect 62

4.2.2 Heat Transfer Analysis ofThermoelectric Power Generation 64

4.3 Near-FieldThermal Radiation andThermophotovoltaic Power Generation 66

4.3.1 Introduction 66

4.3.2 Theoretical Framework: Fluctuational Electrodynamics 67

4.3.3 Introduction toThermophotovoltaic Power Generation and Physics of Near-Field Radiative Heat Transfer between Two Bulk Materials Separated by a Subwavelength Vacuum Gap 70

4.3.4 Nanoscale-Gap Thermophotovoltaic Power Generation 76

4.4 Conclusions 80

Acknowledgments 80

References 81

5 Power Conditioning for Energy Harvesting – Theory and Architecture 85
Stephen G. Burrow and Paul D.Mitcheson

5.1 Introduction 85

5.2 The Function of Power Conditioning 85

5.2.1 Interface to the Harvester 86

5.2.2 Circuits with Resistive Input Impedance 87

5.2.3 Circuits with Reactive Input Impedance 89

5.2.4 Circuits with Nonlinear Input Impedance 90

5.2.5 Peak Rectifiers 90

5.2.6 Piezoelectric Pre-biasing 92

5.2.7 Control 94

5.2.7.1 Voltage Regulation 94

5.2.7.2 Peak Power Controllers 96

5.2.8 System Architectures 97

5.2.8.1 Start-Up 97

5.2.9 Highly Dynamic Load Power 98

5.3 Summary 100

References 100

6 ThermoelectricMaterials for Energy Harvesting 103
Andrew C.Miner

6.1 Introduction 103

6.2 Performance Considerations in Materials Selection: zT 103

6.2.1 Properties of Chalcogenides (Group 16) 106

6.2.2 Properties of Crystallogens (Group 14) 106

6.2.3 Properties of Pnictides (Group 15) 107

6.2.4 Properties of Skutterudites 108

6.3 Influence of Scale on Material Selection and Synthesis 110

6.3.1 Thermal Conductance Mismatch 111

6.3.2 Domination of Electrical Contact Resistances 112

6.3.3 Domination of Bypass Heat Flow 113

6.3.4 Challenges inThermoelectric Property Measurement 113

6.4 Low Dimensionality: Internal Micro/Nanostructure and Related Approaches 114

6.5 Thermal Expansion and Its Role in Materials Selection 115

6.6 Raw Material Cost Considerations 116

6.7 Material Synthesis with Particular Relevance to Micro Energy Harvesting 116

6.7.1 Electroplating, Electrophoresis, Dielectrophoresis 117

6.7.2 Thin andThick Film Deposition 118

6.8 Summary 118

References 119

7 Piezoelectric Materials for Energy Harvesting 123
Emmanuel Defay, Sébastien Boisseau, and Ghislain Despesse

7.1 Introduction 123

7.2 What Is Piezoelectricity? 123

7.3 Thermodynamics: the RightWay to Describe Piezoelectricity 125

7.4 Material Figure of Merit: the Electromechanical Coupling Factor 126

7.4.1 Special Considerations for Energy Harvesting 128

7.5 Perovskite Materials 129

7.5.1 Structure 129

7.5.1.1 Ferroelectricity in Perovskites 129

7.5.1.2 Piezoelectricity in Perovskites: Poling Required 131

7.5.2 PZT Phase Diagram 131

7.5.3 Ceramics 132

7.5.3.1 Fabrication Process 132

7.5.3.2 Typical Examples for Energy Harvesting 134

7.5.4 Bulk Single Crystals 135

7.5.4.1 Perovskites 135

7.5.4.2 Energy Harvesting with Perovskites Bulk Single Crystals 135

7.5.5 Polycrystalline PerovskitesThin Films 136

7.5.5.1 Fabrication Processes 136

7.5.5.2 Energy Harvesting with Poly-PZT Films 136

7.5.6 Single-Crystal Thin Films 137

7.5.6.1 Fabrication Process 137

7.5.6.2 Energy Harvesting with SC Perovskite Films 137

7.5.7 Lead-Free 138

7.5.7.1 Energy Harvesting with Lead-Free Materials 139

7.6 Wurtzites 139

7.6.1 Structure 139

7.6.2 Thin Films and Energy Harvesting 140

7.6.3 Doping 141

7.7 PVDFs 141

7.7.1 Structure 141

7.7.2 Synthesis 143

7.7.3 Energy Harvesters with PVDF 143

7.8 Nanomaterials 143

7.9 Typical Values for the Main Piezoelectric Materials 144

7.10 Summary 145

References 145

8 Electrostatic/Electret-Based Harvesters 149
Yuji Suzuki

8.1 Introduction 149

8.2 Electrostatic/Electret Conversion Cycle 149

8.3 Electrostatic/Electret Generator Models 151

8.3.1 Configuration of Electrostatic/Electret Generator 151

8.3.2 Electrode Design for Electrostatic/Electret Generator 153

8.4 Electrostatic Generators 156

8.4.1 Design and Fabrication Methods 156

8.4.2 Generator Examples 158

8.5 Electrets and Electret Generator Model 160

8.5.1 Electrets 160

8.5.2 Electret Materials 161

8.5.3 Charging Technologies 162

8.5.4 Electret Generator Model 163

8.6 Electret Generators 168

8.7 Summary 171

References 171

9 Electrodynamic Vibrational Energy Harvesting 175
Shuo Cheng, Clemens Cepnik, and David P. Arnold

9.1 Introduction 175

9.2 Theoretical Background 178

9.2.1 Energy Storage, Dissipation, and Conversion 178

9.2.2 Electrodynamic Physics 179

9.2.2.1 Faraday’s Law 179

9.2.2.2 Lorentz Force 180

9.2.3 Simplified Electrodynamic Equations 180

9.3 Electrodynamic Harvester Architectures 181

9.4 Modeling and Optimization 183

9.4.1 Modeling 184

9.4.1.1 Lumped Element Method 184

9.4.1.2 Finite Element Method 188

9.4.1.3 Combination of Lumped Element Model and Finite Element Model 189

9.4.2 Optimization 190

9.5 Design and Fabrication 191

9.5.1 Design of Electrodynamic Harvesters 192

9.5.2 Fabrication of Electrodynamic Harvesters 194

9.6 Summary 196

References 197

10 Piezoelectric MEMS Energy Harvesters 201
Jae Yeong Park

10.1 Introduction 201

10.1.1 The General Governing Equation 202

10.1.2 Design Consideration 203

10.2 Development of Piezoelectric MEMS Energy Harvesters 204

10.2.1 Overview 204

10.2.2 Fabrication Technologies 205

10.2.3 Characterization 211

10.2.3.1 Frequency Response 211

10.2.3.2 Output Power of Piezoelectric MEMS Energy Harvesters 211

10.3 Challenging Issues in Piezoelectric MEMS Energy Harvesters 213

10.3.1 Output Power 213

10.3.2 Frequency Response 215

10.3.3 Piezoelectric Material 217

10.4 Summary 218

References 218

11 Vibration Energy Harvesting fromWideband and Time-Varying Frequencies 223
Lindsay M.Miller

11.1 Introduction 223

Contents XI

11.1.1 Motivation 223

11.1.2 Classification of Devices 223

11.1.3 General Comments 225

11.2 Active Schemes for Tunable Resonant Devices 225

11.2.1 Stiffness Modification for Frequency Tuning 226

11.2.1.1 Modify L 226

11.2.1.2 Modify E 227

11.2.1.3 Modify keff Using Axial Force 227

11.2.1.4 Modify keff Using an External Spring 229

11.2.1.5 Modify keff Using an Electrical External Spring 231

11.2.2 Mass Modification for Frequency Tuning 232

11.3 Passive Schemes for Tunable Resonant Devices 232

11.3.1 Modify meff by Coupling Mass Position with Beam Excitation 233

11.3.2 Modify keff by Coupling Axial Force with Centrifugal Force from Rotation 234

11.3.3 Modify L by Using Centrifugal Force to Toggle Beam Clamp Position 234

11.4 Wideband Devices 235

11.4.1 Multimodal Designs 236

11.4.2 Nonlinear Designs 237

11.5 Summary and Future Research Directions 240

11.5.1 Summary of Tunable andWideband Strategies 240

11.5.2 Areas for Future Improvement in Tunable andWideband Strategies 241

11.5.2.1 Tuning range and resolution 241

11.5.2.2 Tuning sensitivity to driving vibrations 242

11.5.2.3 System Size considerations 242

References 243

12 Micro Thermoelectric Generators 245
Ingo Stark

12.1 Introduction 245

12.2 Classification of Micro Thermoelectric Generators 247

12.3 General Considerations for MicroTEGs 250

12.4 Micro Device Technologies 252

12.4.1 Research and Development 253

12.4.1.1 Electrodeposition 253

12.4.1.2 Silicon-MEMS Technology 253

12.4.1.3 CMOS-MEMS Technology 254

12.4.1.4 Other 255

12.4.2 Commercialized Micro Technologies 257

12.4.2.1 Micropelt Technology 257

12.4.2.2 Nextreme/Laird Technology 258

12.4.2.3 Thermogen Technology 259

12.5 Applications of Complete Systems 260

12.5.1 Energy-Autonomous Sensor for Air Flow Temperature 261

12.5.2 Wireless Pulse Oximeter SpO2 Sensor 261

12.5.3 Intelligent Thermostatic Radiator Valve (iTRV) 262

12.5.4 Wireless Power Generator Evaluation Kit 263

12.5.5 Jacket-IntegratedWireless Temperature Sensor 263

12.6 Summary 264

References 265

13 Micromachined Acoustic Energy Harvesters 271
Stephen Horowitz and Mark Sheplak

13.1 Introduction 271

13.2 Historical Overview 272

13.2.1 A Brief History 272

13.2.2 Survey of Reported Performance 274

13.3 Acoustics Background 276

13.3.1 Principles and Concepts 276

13.3.2 Fundamentals of Acoustics 276

13.3.3 Challenges of Acoustic Energy Harvesting 277

13.4 Electroacoustic Transduction 277

13.4.1 Modeling 278

13.4.1.1 Lumped Element Modeling (LEM) 278

13.4.1.2 Equivalent Circuits 279

13.4.1.3 Transduction 280

13.4.1.4 Numerical Approaches 281

13.4.2 Impedance Matching and Energy Focusing 281

13.4.3 Transduction Methods 281

13.4.3.1 Piezoelectric Transduction 281

13.4.3.2 Electromagnetic Transduction 282

13.4.3.3 Electrostatic Transduction 282

13.4.3.4 Comparative Analysis 283

13.4.4 Transduction Structures 284

13.4.4.1 Structures for Impedance Matching 284

13.4.4.2 Structures for Acoustical to Mechanical Transduction 286

13.5 Fabrication Methods 288

13.5.1 Materials 288

13.5.2 Processes 289

13.6 Testing and Characterization 289

13.7 Summary 290

Acknowledgments 290

References 290

14 Energy Harvesting from Fluid Flows 297
Andrew S. Holmes

14.1 Introduction 297

14.2 Fundamental and Practical Limits 298

Contents XIII

14.3 MiniatureWind Turbines 301

14.3.1 Scaling Effects in MiniatureWind Turbines 302

14.3.1.1 Turbine Performance 302

14.3.1.2 Generator and Bearing Losses 305

14.4 Energy Harvesters Based on Flow Instability 306

14.4.1 Vortex Shedding Devices 307

14.4.2 Devices Based on Galloping and Flutter 310

14.5 Performance Comparison 316

14.6 Summary 317

References 317

15 Far-Field RF Energy Transfer and Harvesting 321
Hubregt J. Visser and Ruud Vullers

15.1 Introduction 321

15.2 Nonradiative and Radiative (Far-Field) RF Energy Transfer 322

15.2.1 Nonradiative Transfer 322

15.2.2 Radiative Transfer 323

15.2.3 Harvesting versus Transfer 324

15.3 Receiving Rectifying Antenna 326

15.3.1 Antenna–Rectifier Matching 326

15.3.1.1 Voltage Boosting Technique 327

15.3.1.2 Antenna Matched to Rectifier 328

15.3.1.3 Antenna Not Matched to the Rectifier/Multiplier 329

15.3.1.4 Consequences for the Rectifier and the Antenna Design 330

15.4 Rectifier 330

15.4.1 RF Input Impedance 331

15.4.2 DC Output Voltage 332

15.4.3 Antenna 334

15.4.3.1 50 Ω Antenna 335

15.4.3.2 Complex Conjugately Matched Antenna 335

15.4.4 Rectenna Results 336

15.4.5 Voltage Up-Conversion 339

15.5 Transmission 340

15.6 Examples and Future Perspectives 341

15.7 Conclusions 344

References 344

16 Microfabricated Microbial Fuel Cells 347
Hao Ren and Junseok Chae

16.1 Introduction 347

16.2 Fundamentals of MEMS MFC 348

16.2.1 Operation Principle 348

16.2.1.1 Structure 348

16.2.1.2 Materials 350

16.2.2 Critical Parameters for Testing 350

16.2.2.1 Anode and Cathode Potential, the Total Cell Potential 350

16.2.2.2 Open Circuit Voltage (EOCV) 351

16.2.2.3 Areal/Volumetric Current Density and Areal/Volumetric Power Density 351

16.2.2.4 Internal Resistance and Areal Resistivity 352

16.2.2.5 Efficiency 353

16.3 Prior Art MEMS MFCS 354

16.4 FutureWork 355

16.4.1 Reducing Areal Resistivity 355

16.4.1.1 Applying Materials with High Surface-Area-to-Volume Ratio 355

16.4.1.2 Mitigating Oxygen Intrusion 358

16.4.2 Autonomous Running 359

16.4.3 Elucidating the EET Mechanism 359

References 359

17 Micro Photovoltaic Module Energy Harvesting 363
Shunpu Li ,WensiWang, NingningWang, Cian O’Mathuna, and Saibal Roy

17.1 Introduction 363

17.1.1 p-n Junction and Crystalline Si Solar Cells 363

17.1.2 Amorphous Silicon Solar Cell 366

17.1.3 CIGS and CdTe Solar Cell Development 367

17.1.4 Polymer Solar Cell 370

17.1.5 Dye-Sensitized Solar Cells (DSSC) 373

17.2 Monolithically Integration of Solar Cells with IC 375

17.3 Low-Power Micro Photovoltaic Systems 376

17.3.1 Maximum Power Point Tracking 376

17.3.2 Output Voltage Regulation 379

17.3.3 Indoor-Light-PoweredWireless Sensor Networks – a Case Study 380

17.4 Summary 382

References 383

18 Power Conditioning for Energy Harvesting – Case Studies and Commercial Products 385
Paul D.Mitcheson and Stephen G. Burrow

18.1 Introduction 385

18.2 Submilliwatt Electromagnetic Harvester Circuit Example 386

18.3 Single-Supply Pre-biasing for Piezoelectric Harvesters 388

18.4 Ultra-Low-Power Rectifier and MPPT for Thermoelectric Harvesters 392

18.5 Frequency Tuning of an Electromagnetic Harvester 393

18.6 Examples of Converters for Ultra-Low-Output Transducers 396

18.7 Power Processing for Electrostatic Devices 397

18.8 Commercial Products 397

18.9 Conclusions 398

References 399

19 Micro Energy Storage: Considerations 401
Dan Steingart

19.1 Introduction 401

19.2 Boundary Conditions 401

19.2.1 Microbatteries 404

19.2.2 Supercapacitors 405

19.3 Primary Energy Storage Approaches 405

19.3.1 Volume-Constrained versus Conformally Demanding Approaches 408

19.3.2 Caveat Emptor 409

19.3.3 FutureWork and First-Order Problems 409

References 410

20 Thermoelectric Energy Harvesting in Aircraft 415
Thomas Becker, Alexandros Elefsiniotis, andMichail E. Kiziroglou

20.1 Introduction 415

20.2 Aircraft Standardization 416

20.3 AutonomousWireless Sensor Systems 417

20.4 Thermoelectric Energy Harvesting in Aircraft 419

20.4.1 Efficiency of a Thermoelectric Energy Harvesting Device 420

20.4.2 StaticThermoelectric Energy Harvester 421

20.4.3 Dynamic Thermoelectric Energy Harvester 423

20.5 Design Considerations 425

20.6 Applications 427

20.6.1 StaticThermoelectric Harvester for Aircraft Seat Sensors 427

20.6.2 The Dynamic Thermoelectric Harvesting Prototype 428

20.6.3 Heat Storage Thermoelectric Harvester for Aircraft Strain Sensors 428

20.6.4 Outlook 430

20.7 Conclusions 432

References 433

21 Powering Pacemakers with Heartbeat Vibrations 435
M. Amin Karami and Daniel J. Inman

21.1 Introduction 435

21.2 Design Specifications 436

21.3 Estimation of Heartbeat Oscillations 437

21.4 Linear Energy Harvesters 438

21.5 Monostable Nonlinear Harvesters 441

21.6 Bistable Harvesters 446

21.7 Experimental Investigations 450

21.8 Heart Motion Characterization 450

21.9 Conclusions 456

Acknowledgment 457

References 457

Index 459

"The book is loaded with ideas using a wide range of different energy harvesting methods with detailed explanations of the principles of each method and new materials being used to take advantage of the surrounding energy...Engineers interested in energy harvest­ing will find this book to be a very good resource for learning about new methods for parasitically powering low power electronic devices." (IEEE Electrical Insulation 17/03/2017)