SOLAR CELL ENERGY SYSTEMS

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SOLAR CELL ENERGY SYSTEMS Research
Assoc. Prof. Nesimi Ertugrul School of Electrical
and Electronic Engineering University of Adelaide
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100 Renewable Energy Supply by 2050 !Concept
developed by The International Network for
Sustainable Energy
Introduction
PV Cells and Charac.
System Configurations
Research
Pilot studies continues ...
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Solar Energy Conversion Methods
Introduction
PV Cells and Charac.
System Configurations
Research

• Concentrating solar power systems
• Using the sun's heat to produce electricity.
• Passive solar heating and daylighting
• Using solar energy to heat and light buildings.
• Solar hot water
• Heating water with solar energy.
• Solar process heat and space heating and cooling
  Industrial and commercial uses of the sun's
  heat.
• Photovoltaic, PV (solar cell) systems
• Producing electricity directly from sunlight.

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Status of Solar Cell System Activities
Introduction
PV Cells and Charac.
System Configurations
Research
Rapidly growing applications 30 per year, 10
times in California only Globally Predicted
Power 15 GW by 2012 and 70 GW by 2020
Predicted Job growth 2014 ? 500,000 and 2040 ?
2 million Small Scale (up to 10 kW) PV
Systems Installation cost 10/watt for a 2000
watt system. (Total 20,000 !). Increasing
efficiency (costly !) 1 increase generates 20W
more, and 200 saving Emerging applications
Flexible cells, very thin structures, military
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Principle of Solar Cells
Introduction
PV Cells and Charac.
System Configurations
Research
It is based on the ability of semiconductors to
directly convert sunlight to electricity.
Basically, a solar cell is a P-N junction that
absorbs light, releases electrons and holes,
creating a voltage in the cell, which is then
applied to a load
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Best Research-Cell Efficiencies
Introduction
PV Cells and Charac.
System Configurations
Research
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Cell, Module and Array
Introduction
PV Cells and Charac.
System Configurations
Research
One cell produces about 0.5 V Multiple cells
(about 30-36) make a module and several modules
make an array (panel)
In domestic applications Various designs can
interlock with roof tiles and can provide an
aesthetic look and can make installation easier.
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Modeling and Output Characteristics
Introduction
PV Cells and Charac.
System Configurations
Research
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Introduction
PV Cells and Charac.
System Configurations
Research
Modeling and Electrical Characteristics
Power
Current
Isc
Vpp, Ipp
T2 gt T1
T1
T2 gt T1
Isc/2
T1
Voc
Voltage
Current/Voltage characteristic of a battery
? Multiple cell series and parallel connections ?
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Introduction
PV Cells and Charac.
System Configurations
Research
Electrical Output Characteristics ...
MPP
Maximum Power depends on the environment
Insolation, clouds, mobile applications,
reflection and temperature Maximum Power Point
Tracking (MPPT) Algorithms Constant voltage,
constant current, incremental conductance
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System Configurations Typical interconnecting
voltages
Introduction
PV Cells and Charac.
System Configurations
Research
For larger applications an array of cells is used
(connected in series or parallel depending upon
the voltage and current requirements !). System
can be stand-alone, grid connected (GC) or hybrid
!
Small Scale Solar Sys !
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Schematic Diagram of GC PV System
Introduction
PV Cells and Charac.
System Configurations
Research
Inverter Level ! Voltage/Current Source!
In some GC programs around the world, the
customer is compensated for the electricity
flowing into the grid from the distributed energy
resources at a rate (e.g. the utility avoided
cost) different from the rate the utility charges
the customer.
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Schematic Diagram of GC PV System
Introduction
PV Cells and Charac.
System Configurations
Research
Multi-string, smaller inverters
(0.7-5kW). Multiple inverter (redundancy). Not
badly affected by shading.
Series/parallel on DC side. Single DC bus. Single
large inverter and single protection. Affected by
partial shading.
Grouped with DC-DC step-up converters. High
voltage DC link feeds transformerless converter.
One inverter (AC!) per panel. High volume/low
cost.
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Critical Issues About GC PV Systems
Introduction
PV Cells and Charac.
System Configurations
Research

• Static power converter
• Synchronization and loss of synchronization
• Voltage regulation (due to load and supply
  effects!)
• Voltage and Frequency disturbance handling
• DC injection
• Voltage flicker
• Harmonics (a form of electrical noise generated
  by converter!), THD lt5
• EMI
• Voltage/current surge capability
• Disconnection for faults
• Monitoring
• Isolation
• Islanding (distributed energy source or a
  portion of the area electric power system may
  remain energized ... power quality problems!)
• Generator out of synchronization operations
• Feeder reclosing coordination
• Integration with area electric power system
  grounding

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Some of the Research Activities
Introduction
PV Cells and Charac.
System Configurations
Research

• Research group has a very strong hardware and
  software infrastructure and is highly active and
  successful in the areas of emerging wind, solar,
  electrical machines and vehicle technologies.
• Supported by ARC Discovery Grants and SA Premiers
  Research Fund
• Currently, more than 6 PhD students working
  directly in the area of solar and wind generation
  systems, including
• Low Cost, Small-Scale Wind Generation
• Grid-Connected Converter Topologies for
  Photovoltaic Systems
• Power Quality Detection and Analysis
• Investigation and Implementation of Electric
  Assisted Bicycle

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Typical irradiance and real power output
Introduction
PV Cells and Charac.
System Configurations
Research
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Power outputs of all solar energy systems
Introduction
PV Cells and Charac.
System Configurations
Research
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Research Real Time Monitoring PV System
Introduction
PV Cells and Charac.
System Configurations
Research
To measure, store, transmit and/or to manipulate
electrical characteristics from a solar panel (or
array) in remote locations
Wind Speed and Direction Data
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Research Real Time Monitoring PV System
Introduction
PV Cells and Charac.
System Configurations
Research

• All test results logged to an Excel file
• Name of file is auto-generated from current date
  and time
• E.g. Test run on January 21 at 453pm
• gt File generated Jan21_1653.xls
• Can set times to run both I-V and MPPT tests
  throughout the day
• Once automation started
• Program will run round the clock
• Constantly check the test times with the current
  system time
• If a match has been found, then that
  corresponding test is executed automatically
• Tests run include measurements of environmental
  conditions

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Introduction
PV Cells and Charac.
System Configurations
Research
Research Low-Cost Converter Technology
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Conclusions

• Rapidly growing technology and job prospect
  (including other renewable energy sources and
  technologies, such as wind !).
• Very active research area both system level and
  component level.
• Sustainable Engineering degree covers various
  aspects of the applied technology.