Photovoltaic Principles and Design

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Presenters:

Outline

Why Renewable Energy?

The Power of the Sun

The Science of Photovolt-

aics

Designing PV

system and

Tracking Algorithm

Outline

Why Renewable Energy?

The Power of the Sun

The Science of Photovolt-

aics

Designing PV system

and Tracking

Algorithm

Growing Energy Requirements

• the growth of the world population• rising standards of living

Tightening of Resources

world energy consumption continues to grow

Only coal was estimated to last for about 200 year

lack of fuels will lead to strongly rising prices and distribution wars

Climate Change

The heat energy remains in the atmosphere due to CO2 and only a small amount is returned back in to Space Greenhouse Effect

Outline

Why Renewable Energy?

The Power of the Sun

The Science of Photovolt-

aics

Designing PV system

and Tracking

Algorithm

Energy Distribution of Sunlight

Global Radiation Maps

Radiation Availability and World Energy Consumption

The Position of the Sun

The Sun’s Path

Outline

Why Renewable Energy?

The Power of the Sun

The Science of Photovolt-

aics

Designing PV system

and Tracking

Algorithm

The p-n Junction

Generating power

E = hc / λ

• The packet of energy for a violet photon is about twice as large as for a red photon

• Moving from one band to another requires a ‘quantum leap’

• Infrared photons don’t generally have the necessary amount of energy

• Most violet photons towards the end of the spectrum have excess energy that is dissipated as heat

• 20% efficiency is left

Solar Cell Parameters 1

Open Circuit Voltage Voc 0.5 V – 0.6 V

Short Circuit Current Isc proportional to the strength of the sunlight

Maximum Power Point Pmp=Imp*Vmp

Solar Cell Parameters 2

The Fill Factor widely used measure of performance that reflects the overall quality of the cell

FF = Vmp*Imp / Voc*Isc

FF = PMPP / Voc*Isc

Temperature Dependency of Solar Cells

Solar module Ratings

The power of a solar module is measured according to Standard limiting conditions:

Full Sun radiation (radiation strength E = 1000 W/m2)

Temperature of the solar module: T=25 °C

The rated power (or nominal power) of the module is given in Watt-Peak (Wp) describing the peak power of the module under optimal conditions

Design of Solar Modules

Solar Module Simulation

Outline

Why Renewable Energy?

The Power of the Sun

The Science of Photovolt-

aics

Designing PV system

and Tracking

Algorithm

PV Systems

I. Grid Connected (use the National Grid as backup)

II. Stand-alone (use batteries as backup)

III. Hybrid (use generators and batteries as backup)

Grid Connected System

By 2009, more than 95% of solar cell production was being deployed in grid - connected systems

The Grid supply the power needed at night

A part of the power produced at peak Sun hours is connected to the Grid and sold

Scheme of Grid Connected System

PV combiner unit

Protection unit

DC to AC Inverter

Energy - flow metering

junction box connected to utility

DC to AC Inverter

Use advanced electronics to produce AC power at the right frequency and voltage to match the grid supply

Must be able to handle wide output power range (different sunlight conditions)

They do this using maximum power point tracking (MPPT)

DC to AC conversion efficiencies up to 98%

Tracking Algorithm : P and O

STEADY-STATE OPERATION VS RAPIDLY CHANGING IRRADIANCE CONDITIONS

Perturb & Observe Simulation

Conclusion

Energy densities for renewable energies are small → large areas are needed in order to “collect” sufficient energy → high cost of production

As technology grows, the cost of production decreases

In the next 100 years, solar energy will sure be the major provider of energy for world’s consumption

Any Questions?

Thank you For Your Attention