Solar Cell Array Design Handbook

I Solar Cell Arrays.- 1 Array Systems.- Array Concepts.- 1-1. Arrays and Batteries.- 1-2. Arrays, Panels, Parts, and Components.- 1-3. Array Types.- 1-4. The Array as Part of the Power System.- 1-5. The Array as a System.- 1-6. Hybrid Systems 6 Historical Developments.- 1-7. History of Terrestrial Arrays.- 1-8. History of Space Arrays.- 1 -9. The Future of Solar Cell Arrays.- Array Applications.- 1-10. Terrestrial Applications.- 1-11. Space Applications.- 1-12. Power from Space.- Array Systems Performance.- 1-13. Array Ratings.- 1-14. Terrestrial Flat-Plate Arrays.- 1-15. Terrestrial Concentrator Arrays.- 1-16. Space Flat-Hate Arrays.- 1-17. Spinning Space Arrays.- 1-18. Space Concentrator Arrays.- 1-19. Space Array Orbital Performance.- 2 Array Analysis.- Analytical Concepts.- 2-1. The Role of Analysis.- 2-2. Atoms and Electrons.- 2-3. Electric Charge.- 2-4. Conductors.- 2-5. Insulators.- 2-6. Current.- 2-7. Electric Field.- 2-8. Potential and Voltage.- 2-9. Electrical Circuits.- 2-10. Sources and Generators.- 2-11. Current Flow Convection.- 2-12. Resistance and Resistors.- 2-13. Ohm's Law.- 2-14. Power.- 2-15. Energy.- 2-16. Capacitance and Capacitors.- 2-17. Magnetism.- 2-18. Inductance and Inductors.- 2-19. AC and DC Current.- 2-20. Impedance.- Circuit Analysis.- 2-21. Circuit Modelling.- 2-22. Circuit Simplifications.- 2-23. Circuit Responses.- 2-24. Circuit Equations.- 2-25. Operating Points.- Semiconductors and Solar Cell Models.- 2-26. Quantum Mechanics.- 2-27. Semiconductor Materials.- 2-28. Semiconductor Junctions.- 2-29. Solar Cell Operation.- 2-30. Solar Cell Equation.- 2-31. Solar Cell DC Model.- 2-32. Distributed Parameter Solar Cell Model.- 2-33. Analytical Models for Computer Work.- 2-34. Non-Analytical Computer Models.- 2-35. Selecting the Proper Model.- 2-36. Solar Cell AC Model.- 2-37. Solar Cells in Parallel and Series.- 2-38. Illuminated Arrays.- 2-39. Partially Shadowed Cells in Parallel.- 2-40. Partially Shadowed Cells in Series.- 2-41. Solar Cell Strings with Shunt Diodes.- 2-42. Shadowing Factors.- 2-43. Nonilluminated Array Models.- 2-44. Blocking Diode Models.- 2-45. Reverse-Biased Solar Cells.- 2-46. Power Dissipation in Reverse-Biased Solar Cells.- Array Performance Prediction.- 2-47. Array Output Analysis.- 2-48. Sequence of Shifting I-V Curves.- 2-49. Calculation of Angle of Incidence.- 2-50. Calculation of Effective Solar Intensity.- 2-51. Calculation of Cell and Array I-V Curves.- Shadow Analysis.- 2-52. Shadows 84 Thermal Analysis.- Thermal Analysis.- 2-53. Heat Flow and Temperature.- 2-54. Heat Transfer by Conduction.- 2-55. Heat Transfer by Convection.- 2-56. Heat Transfer by Radiation.- 2-57. Electrical Heat Transfer Analogy.- 2-58. Terrestrial Array Operating Temperatures.- Reliability.- 2-59. Reliability and Failure Rates.- 2-60. Failure Modes and Effects.- 2-61. Reliability Models.- Orbital Analysis.- 2-62. Spacecraft Motion in Orbit.- 2-63. Simplified Orbit Theory.- 2-64. Altitude in Elliptic Orbits.- 2-65. Location in Space.- 2-66. Illumination of the Orbit Plane.- 2-67. The Sun Angle.- 2-68. Solar Eclipses.- 3 Array Design.- Design Concepts.- 3-1. The Design Process.- 3-2. Design Phases.- 3-3. Design Personnel.- 3-4. Uncertainties and Risks.- 3-5. Design Optimization.- 3-6. Design Requirements, Criteria and Interfaces.- 3-7. Policy Constraints.- 3-8. Design Review.- 3-9. Producibility and Cost.- 3-10. Human Engineering.- Photovoltaic System Design.- 3-11. Load Profile Development.- 3-12. Illumination Profile Development.- 3-13. Preliminary Array Sizing-Area Method.- 3-14. Preliminary Array Sizing-Cell Efficiency Method.- 3-15. Preliminary Array Sizing-Cell Power Method.- Detailed Array Design.- 3-16. Detailed Array Sizing.- 3-17. Space Array Configuration Selection.- 3-18. Number of Required Solar Cells.- 3-19. Array Layout.- 3-20. Array Wiring.- 3-21. Hot Spot Design Considerations.- 3-22. Designing for Reliability.- 3-23. High Voltage Design.- Thermal Design.- 3-24. Temperature Control in Space.- 3-25. Temperature Control on Earth.- 3-26. Decreasing Absorptance.- 3-27. Increasing Emittance.- 3-28. Increasing Convection.- 3-29. Improving the Geometry.- 3-30. Minimizing Eclipse Exit Temperatures.- Radiation Shielding Design.- 3-31. Solar Cell Radiation Shielding.- 3-32. Damage-Equivalent Fluence in Orbit.- 3-33. Shielding Thickness Determination.- 3-34. Procedure for 1-MeV Fluence Analysis.- 3-35. Shielding Against Low Energy Protons.- 3-36. Absorbed Dose in Cover and Adhesive.- Electromagnetic Design.- 3-37. Electrostatic Shielding.- 3-38. Magnetic Cleanliness.- 3-39. Minimizing Magnetic Moments.- 3-40. Electrostatic Charging Control.- II Array Building Blocks.- 4 Solar Cells.- Photovoltaics.- 4-1. Solar Cell Devices.- 4-2. Direct Energy Conversion.- 4-3. Discovery of the Photovoltaic Effect.- 4-4. History of Contemporary Silicon Cells.- 4-5. History of Non-Silicon Cells.- Solar Cell Types.- 4-6. Solar Cell Classification.- 4 - 7. Classification According to Application.- 4-8. Classification According to Materials.- 4 -9. Classification According to Construction.- 4-10. Classification According to Optical Features.- 4-11. Contemporary Silicon Solar Cell Types for Space Use.- 4-12. Contemporary Silicon Solar Cells for Terrestrial Use.- Electrical Characteristics.- 4-13. Solar Cell Polarity.- 4-14. Current-Voltage Characteristics.- 4-15. Series Resistance.- 4-16. Shunt Resistance.- 4-17. Energy Conversion Efficiency.- 4-18. Curve and Fill Factors.- 4-19. Effects of Solar Intensity.- 4-20. Reversible Effects of Temperature.- 4-21. Temperature Coefficients.- 4-22. Irreversible Temperature Effects.- 4-23. High-Intensity, High-Temperature Operation.- 4-24. Low-Intensity, Low-Temperature Operation.- 4-25. Reverse Characteristics.- Optical Characteristics.- 4-26. Effects of Optical Characteristics on Cell Efficiency.- 4-27. Spectral Response Defined.- 4-28. Spectral Response of Solar Cells.- Mechanical Characteristics.- 4-29. Solar Cell Sizes and Shapes.- 4-30. Cell Thicknesses.- 4-31. Active Area.- Contacts.- 4-32. Solar Cell Contact Types.- 4-33. Contact Configurations.- 4-34. Contact Strength.- Radiation Effects.- 4-35. Solar Cell Radiation Damage.- 4-36. Damage-Equivalent 1-MeV Fluence.- 4-37. Effects of Base Resistivity.- 4-38. Low-Energy Proton Damage.- 4-39. Radiation Damage Annealing and Output Instabilities.- Practical Considerations.- 4-40. Glassed Cell Output.- 4-41. Distribution of Parameters.- 4-42. Handling Precautions.- 4-43. Storage.- 4-44. Solar Cell Space Flight Experiments.- 4-45. Laboratory Test Data for Space Cells.- 4-46. Radiation Test Data for Space Cells.- 5 Optical Elements.- Functions of Optical Elements.- 5-1. Flat-Plat Optics.- 5-2. Concentrator Optics.- 5-3. Historical Developments.- Optical Energy Transfer.- 5-4. The Optical System.- 5-5. The Air (or Space)-To-Cover Interface.- 5-6. The Cover-To-Cell Interface.- 5-7. Glassing Factors.- 5-8. Angle-of-Incidence Effects.- 5-9. Thermal Control.- Covers for Space Applications.- 5-10. Classification of Covers and Coatings.- 5-11. Cover Materials.- 5-12. Coatings and Filters.- 5-13. Mechanical Characteristics.- 5-14. Conductive Coatings.- 5-15. Cover Adhesives.- 5-16. Integral Organic Covers.- Windows for Terrestrial Applications.- 5-17. Window Construction.- 5-18. Window Requirements.- 5-19. Window Materials.- Sunlight Concentrators.- 5-20. Principles of Sunlight Concentration.- 5-21. Concentrator Types.- 6 Electrical Elements.- Solar Cell Interconnectors.- 6-1. Interconnector Terminology.- 6-2. Interconnector Types.- 6-3. Solar Cell Interconnector Design Requirements.- 6-4. Solar Cell and Interconnector Failure Modes.- 6 - 5. Historical Developments of Solar Cell Interconnectors.- 6-6. Soldered or Welded Joints?.- The Interconnector Design Problem.- 6 - 7. Interconnector Material Selection.- 6-8. Interconnector Electrical Design.- 6 - 9. Minimizing Thermomechanical Stress.- 6-10. Thermomechanical Stress in Rigid Joints.- 6-11. Stresses in Joints Due to External Forces.- 6-12. Changes in Intercell Gap Width.- 6-13. Loop Deformation.- 6-14. Stresses in Interconnector Expansion Loops.- 6-15. Stress-free Interconnector Loops.- 6-16. Stresses in Imbeded Interconnectors and Conductors.- 6-17. Practical Interconnector Design Considerations.- 6-18. Stresses in Flexible Bonded Layers.- Interconnector Fatigue.- 6-19. Static and Dynamic Material Stress.- 6-20. Stress and Strain Loading.- 6-21. Fatigue of Materials.- 6-22. Fatigue Life of Interconnectors.- Diodes.- 6-23. Diode Applications.- 6-24. Blocking Diodes for Energy Conservation.- 6-25. Blocking Diodes for Fault Isolation.- 6-26. Blocking Diode Characteristics.- 6-27. Shunt Diode Use.- 6-28. Shunt Diode Characteristics.- 6-29. Zener Diodes.- Wiring and Cabling.- 6-30. Wires and Cables.- 6-31. Methods of Wiring.- 6-32. Wiring for Terrestrial Arrays.- 6-33. Wiring for Space Arrays.- 6-34. Wire Insulation Properties.- 6-35. Current Carrying Capability.- Terminals and Connectors.- 6-36. Wire Terminations.- 6-37. Connectors and Terminals for Space Arrays.- 6-38. Connectors and Terminals for Terrestrial Use.- 6-39. Termination Design Practices.- 7 Mechanical Elements.- Array Mechanical Characteristics.- 7-1. Array Design Options.- 7-2. Array Mechanical Elements.- Terrestrial Flat Hate Arrays.- 7-3. Flat Plate Modules.- 7-4. Open Frame Supports.- 7-5. Roof Supports.- 7-6. Flat Plate Orientation Mechanisms.- Terrestrial Concentrator Arrays.- 7-7. Linear Concentrator Modules.- 7-8. Axial Concentrator Modules.- 7-9. Mirror Field Systems.- Space Arrays.- 7-10. Space Array Overview.- 7-11. Rigid Honeycomb Panels.- 7-12. Honeycomb Panels With Stiffeners.- 7-13. Flexible Substrates With Rigid Frames.- 7-14. Flexible Fold-Up Blankets.- 7-15. Flexible Roll-Up Blankets.- 7-16. Hybrid Arrays.- 7-17. Other Developments.- Deployment Mechanisms.- 7-18. Deployable Booms.- 7-19. Spring/Actuator Deployment Concepts.- Orientation Drives.- 7-20. Orientation Mechanisms.- 7-21. Stepping Drive Example.- 7-22. Continuous Drive Example.- III Support Data.- 8 Fabrication and Test.- 8-1. Soldering.- 8-2. Welding.- 8-3. Thermocompression Joining.- 8-4. Ultrasonic Joining.- 8-5. Electrical Degradation Due to Joining.- 8-6. Adhesive Bonding.- Assembly Process Control.- 8-7. Metal Joining Control.- 8-8. Nondestructive Testing (NDT).- 8-9. Adhesive Bonding Control.- 8-10. Visual Inspection.- 8-11. Workmanship Criteria.- Photovoltaic Testing.- 8-12. History of Solar Cell-Testing.- 8-13. Standard Solar Cells.- 8-14. light Sources For Solar Cell-Testing.- 8-15. Solar Simulators.- 8-16. Solar Cell Output Measurements.- 8-17. Array Output Measurements.- 8-18. Standard Test Conditions.- 8-19. Effects of Lead and Contact Resistances.- 8-20. Three Types of Solar Cel- V Curves.- 8-21. Measurement of Solar Cell Series Resistance.- 8-22. Dark Forward-Testing.- 8-23. Insulation Resistance and Voltage Breakdown.- Thermo-optical Measurements.- 8-24. Measurement of Spectral Distribution and Spectral Response.- 8-25. Determination of Solar Absorptance.- 8-26. Determination of Hemispherical Emittance.- 8-27. Measurement of Spectral Reflectance.- 8-28. Measurement of Total Reflectance.- Environmental Testing.- 8-29. Particle Radiation Testing.- 8-30. Ultraviolet Radiation-Testing.- 8-31. Far Ultraviolet Testing.- 8-32. Combined Environments-Testing.- 8-33. Temperature Cycling-Testing.- Significance of Test Data.- 8-34. Errors.- 8-35. Uncertainties.- 8-36. Uncertainties in Inspection.- 8-37. Significance of Sample Size.- 9 Environments and Their Effects.- 9-1. The Solar Cell Array Environment.- Solar Energy.- 9-2. The Sun.- 9-3. The Solar Constant.- 9-4. Albedo.- 9-5. Solar Radiation Pressure.- 9-6. Terrestrial Sunshine.- 9-7. Ultraviolet Radiation.- Terrestrial Environments.- 9-8. Temperature-Terrestrial.- 9-9. Humidity.- 9-10. Precipitation.- 9-11. Wind.- 9-12. Sand, Dust, Dirt.- 9-13. Earthquakes.- 9-14. Gravity.- 9-15. The Atmosphere.- 9-16. Atmospheric Electricity.- 9-17. Corrosion.- 9-18. Ozone.- 9-19. Fungi and Bacteria.- 9-20. Salt Spray.- 9-21. Biotic Elements.- 9-22. Vandalism.- Handling and Transportation.- 9-23. Handling and Assembly.- 9-24. Vibration and Acoustic Noise in Transportation.- 9-25. Mechanical Shock in Transportation.- 9-26. Storage.- 9-27. Pressure/Altitude in Transportation.- Launch and Flight of Space Arrays.- 9-28. Dynamic Forces During Launch and Flight.- 9-29. Acceleration.- 9-30. Shock (Mechanical).- 9-31. Vibration.- 9-32. Acoustic Field.- The Space Environment.- 9-33. The Solar System.- 9-34. The Space Vacuum.- 9-35. Meteoroids.- 9-36. Deposits.- 9-37. Gravity in Space.- 9-38. Time in Space.- 9-39. Magnetic Fields.- 9-40. Temperature in Space.- 9-41. Solar Cell Arrays in Orbit.- 9-42. Solar Eclipses.- The Radiation Environment in Space.- 9-43. Radiation Terms.- 9-44. Space Radiation and its Effects.- 9-45. Radiation in Interplanetary Space.- 9-46. Solar Flares.- 9-47. Radiation Near Earth.- 9-48. Radiation At Synchronous Altitude.- 9-49. Geomagnetic Substorms.- 10 Material Properties.- 10-1. Where to Find the Data.- 10-2. Material Properties and the Designer.- General Characteristics.- 10-3. Characteristics of Metals.- 10-4. Characteristics of Non-metals.- 10-5. Density, Mass and Weight.- 10-6. Centroids, Moments of Inertia and Radii of Gyration.- Mechanical Properties.- 10-7. Stress, Strain, and Strength.- 10-8. Stiffness and Bending Stress.- 10-9. Mechanical Properties as Function of Temperature.- 10-10. Elongation and Reduction in Area.- 10-11. Fatigue Life.- 10-12. Mechanical Properties of Elastomers.- 10-13. Outgassing and Weight Loss.- Thermal Properties.- 10-14. Thermal Expansion.- 10-15. Specific Heat and Heat Conductance.- Electromagnetic Properties.- 10-16. Electrical Properties of Conductors.- 10-17. Electrical Properties of Dielectrics.- 10-18. Magnetic Properties.- 10-19. Thermal Emittance 498 Appendices.- Appendices.- Appendix A Mathematics.- Appendix B Insolance Tables.- Appendix C Physical Constants.- Appendix D Conversion Factors and Formulas.- Appendix E 1 MeV Fluence Tables.