ENERGY HARVESTING Solar, Wind, and Ocean Energy Conversion Systems Alireza Khaligti Omer C. Onar Energy, Power Electronics, and Machines Series AH Emadi, Series Editor TECHNiSCHE INFOF.MATIONSBIBLIOTHEK UNIVERSITATSBIBLIOTHEK HANNOVER CRC Press Taylor & Francis Group Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business
Contents Preface Authors xiii xv 1. Solar Energy Harvesting 1 1.1 Introduction 1 1.1.1 Structures of Photovoltaic Cells/Modules/Arrays 1 1.1.2 Semiconductor Materials for PV Cells 3 1.1.3 Active and Passive Solar Energy Systems 5 1.1.4 Components of a Solar Energy System 5 1.2 I-V Characteristics of PV Systems 7 1.3 PV Models and Equivalent Circuits 9 1.3.1 Single-Diode 1.3.2 Single-Diode 1.3.3 Single-Diode and Dual-Diode Models 9 Model without Parallel Resistance 10 Model without Resistances 12 1.3.4 PV Model Performance under Nominal and Standard Conditions 13 1.3.5 Effects of Irradiance and Temperature on PV Characteristics 15 1.4 Sun 15 Tracking Systems 1.5 MPPT Techniques 21 1.5.1 Incremental Conductance Based MPPT Technique 21 1.5.2 Perturb and Observe-Based MPPT 23 1.5.3 MPPT Controller-Based on Linearized J-V Characteristics 24 1.5.4 Fractional Open-Circuit Voltage-Based MPPT 26 1.5.5 Fractional Short-Circuit Current-Based MPPT 27 1.5.6 Fuzzy Logic Control-Based MPPT 28 1.5.7 Neural Network-Based MPPT 30 1.5.8 Ripple Correlation Control-Based MPPT 31 1.5.9 Current Sweep-Based MPPT 32 1.5.10 DC Link Capacitor Droop Control-Based MPPT 33 1.6 Shading Effects on PV Cells 35 1.7 Power Electronic Interfaces for PV Systems 40 1.7.1 Power Electronic Interfaces for Grid-Connected PV Systems 40 1.7.1.1 Topologies 1.7.1.2 Topologies Based on Module and. Stage Configurations... Based on Inverter Utilization 41 42 1.7.2 Power Electronic Interfaces for Stand-Alone PV Systems 61 1.7.2.1 PV/Battery Connection: Type 1 61 vii
viii Contents 1.7.2.2 PV/Battery Connection: Type 2 63 1.7.2.3 PV/Battery Connection: Type 3 64 1.7.2.4 PV/Battery Connection: Type 4 65 1.7.2.5 PV/Battery Connection: Type 5 65 1.8 Sizing the PV Panel and Battery Pack for Stand-Alone PV Applications 66 1.8.1 Sun Hour 67 1.8.2 Load Calculation 67 1.8.3 Days of Autonomy 67 1.8.4 Solar Radiation 68 1.8.5 PV Array Sizing 68 1.8.5.1 PV Module Selection 68 1.8.5.2 System Losses 68 1.8.5.3 Determination of the Number of Series-Connected PV Modules 68 1.8.5.4 Determination of the Number of Parallel-Connected PV Modules 69 1.8.5.5 Design Verification and a Sizing Example 69 1.9 Modern Solar 72 Energy Applications 1.9.1 Residential 72 Applications 1.9.1.1 Boost Converter 74 1.9.1.2 MPPT Control of the PV Panel 77 1.9.1.3 Bidirectional Inverter/Converter 78 1.9.1.4 Power Conditioner 79 1.9.2 Electric Vehicle Applications 81 1.9.2.1 Solar Miner II 84 1.9.3 Naval Applications 86 1.9.3.1 Solar-Powered AUV 87 1.9.3.2 Solar-Powered Boat, Korona 88 1.9.4 Space Applications 89 1.9.4.1 Solar Power Satellite Energy System 90 1.9.4.2 Pathfinder, the Solar Rechargeable Aircraft 90 1.9.4.3 Solar-Powered Aircraft 91 1.9.4.4 Solar Airplane 91 1.9.4.5 Solar-Powered Unmanned Aerial Vehicle 92 1.10 Summary 94 References 94 2. Wind Energy Harvesting 101 2.1 Introduction 101 2.2 Winds 101 2.3 History of Wind Energy Harvesting 104 2.4 Fundamentals of Wind Energy Harvesting 105 2.4.1 Wind Turbine Siting 105 2.4.2 Wind Turbine Power 107 2.4.2.1 BetzLaw 107 2.4.2.2 Power Curve 109 2.4.2.3 Power Coefficient 110
2.5 Wind Turbine Systems 112 2.5.1 Basic Parts of Wind Turbines 112 2.5.1.1 The Tower 112 2.5.1.2 Yaw Mechanism 113 2.5.1.3 The Nacelle 113 2.5.1.4 The Turbine 113 2.6 Wind Turbines 114 2.6.1 Wind Turbines Based on Axis Position 114 2.6.2 Wind Turbines Based on Power Capacity 114 2.7 Different Electrical Machines in Wind Turbines 116 2.7.1 BLDC Machines 116 2.7.2 Permanent Magnet Synchronous Machines 123 2.7.3 Induction Machines 130 2.7.3.1 Conventional Control Scheme 134 2.7.3.2 Voltage and Frequency Control with Load Regulation 134 2.7.3.3 Improved Voltage and Frequency Control with a VSI 135 2.7.3.4 Advanced Voltage and Frequency Control Using VSI 136 2.7.3.5 Back-to-Back Connected PWM VSI 136 2.7.3.6 DFIG 137 2.7.3.7 Voltage and Frequency Control Using Energy Storage Devices 143 2.8 Synchronous Generators 151 2.9 Wind Harvesting Research and Development 156 2.9.1 Developments in Control Systems 156 2.9.2 Developments in Machine Design 158 2.9.3 Developments in Distribution and Grid-Connected Topologies 158... 2.10 Summary 159 References 159 Tidal Energy Harvesting 167 3.1 Introduction 167 3.1.1 History of Tidal Energy Harvesting 169 3.1.2 Physical Principles of Tidal Energy 170 3.2 Categories of Tidal Power and Corresponding Generation Technology... 173 3.2.1 Potential Energy 173 3.2.2 Tidal Barrages Approach 174 3.2.2.1 Ebb Generation 174 3.2.2.2 Flood Generation 174 3.2.2.3 Two-Way Generation 174 3.2.3 Tidal Lagoons Concept 176 3.2.4 Tidal Turbines Used in Barrages 178 3.2.4.1 Bulb Turbine 178 3.2.4.2 Rim Turbine 179 3.2.4.3 Tubular Turbine 179 3.3 Turbine and Generator's Control 180 3.3.1 Modeling of Hydraulic Turbine Conduit Dynamics 181 3.3.2 Hydro Turbine Controls 183 3.3.3 Kinetic Energy 188
X Contents 3.3.3.1 Energy Calculation for Tidal Current Energy Harvesting Technique 189 3.3.3.2 Tidal Turbines Used in Tidal Current Approach 192 3.4 Tidal Energy Conversion Systems 199 3.4.1 Generators 199 3.4.1.1 Synchronous Generator 199 3.4.1.2 Asynchronous Generator 202 3.4.2 Gearbox 205 3.4.3 Optimal Running Principle of Water Turbine 205 3.4.4 Maximum Power Point Tracking 206 3.4.4.1 MPPT Method Based on Look-Up Table 207 3.4.4.2 MPPT Method Based on Current Speed Calculation 208 3.4.5 P&O-Based MPPT Method 208 3.5 Grid Connection Interfaces for Tidal Energy Harvesting Applications... 211 3.5.1 Grid Connection Interfaces for Tidal Turbine Applications 211 3.5.1.1 Grid-Connected Systems 212 3.5.2 Grid Connection and Synchronization for Tidal Energy Harvesting with Basin Constructions 216 3.6 Potential Resources 217 3.7 Environmental Impacts 218 3.7.1 Sediment 218 3.7.2 Fish 219 3.7.3 Salinity 219 3.8 Summary 219 References 219 4. Ocean Wave Energy Harvesting 223 4.1 Introduction to Ocean Wave Energy Harvesting 223 4.2 The Power of Ocean Waves 225 4.3 Wave Energy Harvesting Technologies 226 4.3.1 Offshore Energy Harvesting Topologies 227 4.3.1.1 Dynamics of Fixed Bodies in Water 227 4.3.1.2 Dynamics of Floating Bodies in Water 228 4.3.1.3 Air-Driven Turbines 229 4.3.1.4 Fixed Stator and Directly Driven PM Linear Generator-Based Buoy Applications 230 4.3.1.5 Salter Cam Method 231 4.3.2 Nearshore Energy Harvesting Topologies 233 4.3.2.1 Nearshore Wave Energy Harvesting by the Channel/Reservoir/Turbine Method 233 4.3.2.2 Air-Driven Turbines Based on the Nearshore Wave Energy Harvesting Method 233 4.3.3 Wave Power Absorbers 234 4.3.4 Wave Power Turbine Types 236 4.3.4.1 The "Wells" Air Turbines 237 4.3.4.2 Self-Pitch-Controlled Blades Turbine for WEC 239 4.3.4.3 Kaplan Turbines for WEC 241 4.3.4.4 Other Types of Turbines Used for WEC 243
Contents xi 4.3.5 Wave Power Generators 249 4.3.5.1 A Wave-Activated Linear Generator Model 249 4.3.5.2 Linear, Synchronous, Longitudinal-Flux PM Generators... 255 4.3.5.3 A Three-Phase Synchronous Generator for Ocean Wave Applications 260 4.3.5.4 Radial Flux PM Synchronous Generator for WEC 266 4.3.5.5 Induction Machines for Ocean WEC 272 4.3.5.6 Switched Reluctance Machines for Ocean WEC 274 4.3.5.7 Ocean Energy Conversion Using Piezoelectric/Electrostictive Materials 275 4.3.6 Grid Connection Topologies for Different Generators Used in Wave Energy Harvesting Applications 282 4.3.6.1 Grid Connection Interface for Linear and Synchronous Generator Applications 282 4.3.6.2 Grid Connection Interface for Induction Generator Applications 283 4.3.6.3 Grid Connection Interface for SRG Applications 286 4.3.6.4 Grid Connection Interface for Piezoelectric/Electrostrictive Power Generators 289 4.4 Wave Energy Applications 289 4.4.1 Oscillating Water Column 290 4.4.2 Pelamis 291 4.4.3 Wave Dragon 294 4.4.4 AWS 294 4.4.5 Wave Star Energy 296 4.4.6 Magnetohydrodynamics Wave Energy Converter 298 4.5 Wave Energy in Future 298 4.6 Summary 299 References 299 5. Ocean Thermal Energy Harvesting 305 5.1 History 306 5.2 Classification of OTECs 308 5.2.1 Closed-Cycle OTEC Systems 308 5.2.1.1 Structure and Principles of Closed-Cycle Systems 308 5.2.1.2 Thermodynamic Principles of Closed-Cycle Systems 309 5.3 Technical Obstacles of Closed-Cycle OTEC Systems 312 5.3.1 Working Fluids and Its Potential Leakage 312 5.3.1.1 Degradation of Heat Exchanger Performance by Microbial Fouling 314 5.3.2 Thermal Energy Conversion for OTEC Systems 314 5.3.3 Open-Cycle OTEC Systems 315 5.3.3.1 Structure and Principles of Open-Cycle Systems 315 5.3.3.2 Technical Difficulties of Open-Cycle OTEC Systems 316 5.3.4 Hybrid Cycle OTEC Systems 316 5.3.4.1 Structure and Principles of Hybrid OTEC Systems 316 5.4 Components of an OTEC System 317 5.4.1 Heat Exchanger 318 5.4.2 Evaporator 318
xii Contents 5.4.3 Condenser 322 5.4.4 Vacuum Flash Evaporator 325 5.5 Control of an OTEC Power Plant 326 5.6 Control of a Steam Turbine 329 5.7 Potential Resources 333 5.8 Multipurpose Utilization of OTEC Systems 337 5.8.1 Desalination 337 5.8.2 Aquaculture 337 5.8.3 Air-Conditioning 338 5.8.4 Mineral Extraction 338 5.9 Impact on Environment 338 5.10 Summary 339 References 339 Index 343