SOLAR CARSSOLAR CARS

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AN OVERVIEWAN OVERVIEW Powered by sun’s energyPowered by sun’s energy Solar array collect the energy from the sun and Solar array collect the energy from the sun and

converts it into usable electrical energyconverts it into usable electrical energy Power trackers convert it into the required voltage Power trackers convert it into the required voltage Motor controller sends power to the motorMotor controller sends power to the motor Divided into fiveDivided into five

• Driver Controls & Mechanical Systems Driver Controls & Mechanical Systems • Electrical System Electrical System • Drive Train Drive Train • Solar Array Solar Array • Body and ChassisBody and Chassis

Borealis III Raycing with the Sun - Photo by Colin Burnett

DRIVER CONTROLS & DRIVER CONTROLS & MECHANICAL SYSTEMSMECHANICAL SYSTEMS

Standard featuresStandard features SteeringSteering

• Precise steering alignment Precise steering alignment • SUNRUNNER utilized a rack and pinion system SUNRUNNER utilized a rack and pinion system

that was attached to the steering arms by means of that was attached to the steering arms by means of tie rodstie rods

BrakeBrake• Designed to move freely by eliminating brake dragDesigned to move freely by eliminating brake drag • Hydraulic disc brakes Hydraulic disc brakes • Regenerative brakingRegenerative braking

SuspensionSuspension

• front suspension- MacPhearson struts or double A arms front suspension- MacPhearson struts or double A arms • MacPhearson strut requires a large vertical clearance MacPhearson strut requires a large vertical clearance • Double A arms require less vertical clearance, but Double A arms require less vertical clearance, but

consist of more componentsconsist of more components• rear suspensionrear suspension is a trailing arm, similar to that in is a trailing arm, similar to that in

motor cyclesmotor cycles

WheelsWheels• rolling resistance rolling resistance • three or four wheelsthree or four wheels• wheel designs are similar to those of bicycle tires wheel designs are similar to those of bicycle tires

ELECTRICAL SYSTEMELECTRICAL SYSTEM

Made up of batteries and power electronicsMade up of batteries and power electronics BatteriesBatteries

• Lead-Acid Lead-Acid • Nickel-Metal Hydride (NiMH) Nickel-Metal Hydride (NiMH) • Nickel-Cadmium (NiCad) Nickel-Cadmium (NiCad) • Lithium IonLithium Ion• Tesseract uses 512 li-ion batteriesTesseract uses 512 li-ion batteries

Energy Flow Diagram of a Solar Car

Peak Power TrackersPeak Power Trackers

• maximize the power maximize the power • protect the batteries from being damaged by protect the batteries from being damaged by

overchargingovercharging• efficiencies above 95%efficiencies above 95%

Motor Controllers Motor Controllers • decides how much current actually reaches the motordecides how much current actually reaches the motor• up to 90% efficient up to 90% efficient

DRIVE TRAINDRIVE TRAIN

Consist of the electric motor and the means to by Consist of the electric motor and the means to by which the motor's power is transmitted the wheelwhich the motor's power is transmitted the wheel

power generated is less than 5 hppower generated is less than 5 hp only one wheel in the rear of the car is driven by the only one wheel in the rear of the car is driven by the

electric motorelectric motor motor typesmotor types

• brushed DC brushed DC • dual winding DC brushless dual winding DC brushless • induction induction

Dual-winding DC brushlessDual-winding DC brushless• used as an electronic transmissionused as an electronic transmission

Types of transmissionsTypes of transmissions• variable ratio belt drive variable ratio belt drive • hub motor hub motor

SOLAR ARRAYSOLAR ARRAY made from silicon, by made from silicon, by

joining an n-type and a p-joining an n-type and a p-type semiconductortype semiconductor

grouped into space grade grouped into space grade and terrestrial grade and terrestrial grade categories categories

Encapsulation Encapsulation ArrayArray SUNRUNNER'S array SUNRUNNER'S array

consisted of 14,057 razor-consisted of 14,057 razor-blade sized, 16% efficient blade sized, 16% efficient space grade cells.space grade cells.

Solar arraySolar array

LIMITATIONS LIMITATIONS • Only 1000 W/m2 of energy reaches the earth’s surface Only 1000 W/m2 of energy reaches the earth’s surface

in an hour of “peak sun”in an hour of “peak sun”• average solar array configuration spans 8m² average solar array configuration spans 8m² • total amount of energy hitting the solar car during peak total amount of energy hitting the solar car during peak

sun is 8KWh/m² sun is 8KWh/m² • average solar cells are only able to convert 12% to 18% average solar cells are only able to convert 12% to 18%

to electricity to electricity • the total amount of converted energy available to a car the total amount of converted energy available to a car

consists of 700-1500 Watts consists of 700-1500 Watts • three primary areas of energy loss consist of three primary areas of energy loss consist of • aerodynamic drag, braking, and rolling resistanceaerodynamic drag, braking, and rolling resistance

BODY & CHASSISBODY & CHASSIS

goals goals • minimize the minimize the

aerodynamic drag aerodynamic drag • maximize the exposure maximize the exposure

to solar insolation to solar insolation • minimize weightminimize weight• maximize safety maximize safety

Body ShapesBody Shapes

• Unified aero body and panelUnified aero body and panel • Fixed or tilting, flat panels with a separate driver cab Fixed or tilting, flat panels with a separate driver cab • Catamaran shapeCatamaran shape• uniquely designed shape uniquely designed shape

MAIZE & BLUE and SUNRUNNER are catamaran MAIZE & BLUE and SUNRUNNER are catamaran shaped.shaped.

Chassis Chassis • space framespace frame

• welded tube structure to support the loads and the body welded tube structure to support the loads and the body • body is a lightweight, non-load bearing, composite shellbody is a lightweight, non-load bearing, composite shell

• Semi - monocoque or carbon beamSemi - monocoque or carbon beam • composite beams and bulkheads to support the loads composite beams and bulkheads to support the loads • integrated into a non-load bearing composite belly panintegrated into a non-load bearing composite belly pan

• monocoquemonocoque • uses the body structure to support the loadsuses the body structure to support the loads

MATERIALS USEDMATERIALS USED

composite materialcomposite material combination of a filler material sandwiched between combination of a filler material sandwiched between

layers of a structural material layers of a structural material structural materialsstructural materials

• Carbon fibre, Kevlar and fibre glass Carbon fibre, Kevlar and fibre glass

filler materials filler materials • Honeycomb and foam Honeycomb and foam

bonded together using epoxy resinsbonded together using epoxy resins

FALLING SHORTFALLING SHORT characteristics that a commercially viable car characteristics that a commercially viable car

• extremely reliable extremely reliable • comfortablecomfortable• be able to function on its ownbe able to function on its own• maintain the required speedmaintain the required speed• amenities such as air conditioning, radio, and power locks and amenities such as air conditioning, radio, and power locks and

windowswindows Solar carsSolar cars

• Limited seating capacityLimited seating capacity• Frequent flat tyresFrequent flat tyres• Often was incapable of maintaining highway speedsOften was incapable of maintaining highway speeds

THE FUTURETHE FUTUREIN THE SHORT TERMIN THE SHORT TERM terrestrial application of the rovers that NASA uses in terrestrial application of the rovers that NASA uses in

spacespace Data collection in a hot, sun rich area Data collection in a hot, sun rich area Carry-over of expertise Carry-over of expertise

• substantial advances to the design of electric vehiclessubstantial advances to the design of electric vehicles• better motors, better use of batteries, and better motor better motors, better use of batteries, and better motor

controller designcontroller design composite hull car composite hull car spread the word about the use of harnessing solar spread the word about the use of harnessing solar

power power

IN THE LONG RUNIN THE LONG RUN

Electric carElectric car Increase in petroleum pricesIncrease in petroleum prices short distance commutation short distance commutation improvementsimprovements

THANK YOUTHANK YOU