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Renewable Energy Renewable Energy and LED Lamp Post & and LED Lamp Post &

Energy CenterEnergy CenterProf. Eric Cheng

Dept. of EE

The HK PolyU

Why LED lamp

Long life time Future lighting More method to control and display Low voltage DC Safer Work well with battery

Prototype of Solar LED Lighting and Battery Charging system

Solar LED street light is a big contribution to energy savings

Before (HPS) After (LED)

Solar energy is environmental energy source. LED light has many advantages: Energy saving, low power consumption High efficacy(>70lm/w) Long life span(>50000hours) Controllable light level

Before and after photos of the lighting on the street

Solar LED street light and battery charging system block diagram

Working Mode of Overall System

At daytime, solar panel tracks sunlight to absorb maximum solar energy

At nighttime, reset stepper motor for tomorrow’s tracking sunlight and start LED lighting system.

At dusk time and early morning, tracking sunlight and LED lighting stop operating. Converter also stops operating. Solar street light system is at idle state

Equipment for Lightings

Spectrum of a LEDLamp Complete Analysis System

DC/DC converter

Charging mode At daytime, Solar panel absorbs sunlight and

its output voltage is higher than battery’s voltage. M1 turns off to disconnect LED with converter. Converter works at charging mode.

LED lighting mode At nighttime, Solar panel has no energy

stored in it.M1 turn on to connect LED with converter. Converter works at LED lighting mode. Converter boost battery voltage to LED lighting voltage needed.

LED

D1

M1

R1

M2

M3

L1

C1

Chargi ng mode

LED l i ghti ng mode

Two tracking system

Mechanical tracking system

-Solar panel tracking sunlight Solar panel tracks sunlight step by step with stepper

motor to absorb maximum solar energy Electronic tracking system

-Maximum power point tracking Varies the electrical operating point of the solar panel

so that the solar panel is able to deliver maximum

available power

Main Applications

Streets and highways Parking sites Railroad lines Community areas Rural towns Schools

Energy center

The energy collected from the Solar can also provide additional power source.

It act as an energy center to users We can use the additional power unit for

computer, phone charger

System control

Thank You!