SOLAR CARS

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SOLAR CARS
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AN OVERVIEW

• Powered by suns energy
• Solar array collect the energy from the sun and
  converts it into usable electrical energy
• Power trackers convert it into the required
  voltage
• Motor controller sends power to the motor
• Divided into five
• Driver Controls Mechanical Systems
• Electrical System
• Drive Train
• Solar Array
• Body and Chassis

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Borealis III Raycing with the Sun - Photo by
Colin Burnett
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DRIVER CONTROLS MECHANICAL SYSTEMS

• Standard features
• Steering
• Precise steering alignment
• SUNRUNNER utilized a rack and pinion system that
  was attached to the steering arms by means of tie
  rods
• Brake
• Designed to move freely by eliminating brake drag
  
• Hydraulic disc brakes
• Regenerative braking

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• Suspension
• front suspension- MacPhearson struts or double A
  arms
• MacPhearson strut requires a large vertical
  clearance
• Double A arms require less vertical clearance,
  but consist of more components
• rear suspension is a trailing arm, similar to
  that in motor cycles
• Wheels
• rolling resistance
• three or four wheels
• wheel designs are similar to those of bicycle
  tires

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ELECTRICAL SYSTEM

• Made up of batteries and power electronics
• Batteries
• Lead-Acid
• Nickel-Metal Hydride (NiMH)
• Nickel-Cadmium (NiCad)
• Lithium Ion
• Tesseract uses 512 li-ion batteries

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Energy Flow Diagram of a Solar Car
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• Peak Power Trackers
• maximize the power
• protect the batteries from being damaged by
  overcharging
• efficiencies above 95
• Motor Controllers
• decides how much current actually reaches the
  motor
• up to 90 efficient

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DRIVE TRAIN

• Consist of the electric motor and the means to by
  which the motor's power is transmitted the wheel
• power generated is less than 5 hp
• only one wheel in the rear of the car is driven
  by the electric motor
• motor types
• brushed DC
• dual winding DC brushless
• induction

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• Dual-winding DC brushless
• used as an electronic transmission
• Types of transmissions
• variable ratio belt drive
• hub motor

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SOLAR ARRAY

• made from silicon, by joining an n-type and a
  p-type semiconductor
• grouped into space grade and terrestrial grade
  categories
• Encapsulation
• Array
• SUNRUNNER'S array consisted of 14,057 razor-blade
  sized, 16 efficient space grade cells.

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Solar array
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LIMITATIONS

• Only 1000 W/m2 of energy reaches the earths
  surface in an hour of peak sun
• average solar array configuration spans 8m²
• total amount of energy hitting the solar car
  during peak sun is 8KWh/m²
• average solar cells are only able to convert 12
  to 18 to electricity
• the total amount of converted energy available to
  a car consists of 700-1500 Watts
• three primary areas of energy loss consist of
• aerodynamic drag, braking, and rolling resistance
  

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BODY CHASSIS

• goals
• minimize the aerodynamic drag
• maximize the exposure to solar insolation
• minimize weight
• maximize safety

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• Body Shapes
• Unified aero body and panel
• Fixed or tilting, flat panels with a separate
  driver cab
• Catamaran shape
• uniquely designed shape
• MAIZE BLUE and SUNRUNNER are catamaran shaped.

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• Chassis
• space frame
• welded tube structure to support the loads and
  the body
• body is a lightweight, non-load bearing,
  composite shell
• Semi - monocoque or carbon beam
• composite beams and bulkheads to support the
  loads
• integrated into a non-load bearing composite
  belly pan
• monocoque
• uses the body structure to support the loads

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MATERIALS USED

• composite material
• combination of a filler material sandwiched
  between layers of a structural material
• structural materials
• Carbon fibre, Kevlar and fibre glass
• filler materials
• Honeycomb and foam
• bonded together using epoxy resins

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FALLING SHORT

• characteristics that a commercially viable car
• extremely reliable
• comfortable
• be able to function on its own
• maintain the required speed
• amenities such as air conditioning, radio, and
  power locks and windows
• Solar cars
• Limited seating capacity
• Frequent flat tyres
• Often was incapable of maintaining highway speeds

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THE FUTURE

• IN THE SHORT TERM
• terrestrial application of the rovers that NASA
  uses in space
• Data collection in a hot, sun rich area
• Carry-over of expertise
• substantial advances to the design of electric
  vehicles
• better motors, better use of batteries, and
  better motor controller design
• composite hull car
• spread the word about the use of harnessing solar
  power

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IN THE LONG RUN

• Electric car
• Increase in petroleum prices
• short distance commutation
• improvements

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THANK YOU