Transcript SOLAR CARS - Mechanical Engineering Online

SOLAR CARS
AN OVERVIEW





Powered by sun’s 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
Borealis III Raycing with the Sun
- Photo by Colin Burnett
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

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
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
Energy Flow Diagram of a Solar Car

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
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

Dual-winding DC brushless
•

used as an electronic transmission
Types of transmissions
•
•
variable ratio belt drive
hub motor
SOLAR ARRAY





made from silicon, by
joining an n-type and a ptype semiconductor
grouped into space grade
and terrestrial grade
categories
Encapsulation
Array
SUNRUNNER'S array
consisted of 14,057 razorblade sized, 16% efficient
space grade cells.
Solar array
LIMITATIONS
•
•
•
•
•
•
•
Only 1000 W/m2 of energy reaches the earth’s 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
BODY & CHASSIS

goals
•
•
•
•
minimize the
aerodynamic drag
maximize the exposure
to solar insolation
minimize weight
maximize safety

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.

Chassis
•
space frame
•
•
•
Semi - monocoque or carbon beam
•
•
•
welded tube structure to support the loads and the body
body is a lightweight, non-load bearing, composite shell
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
MATERIALS USED
composite material
 combination of a filler material sandwiched between
layers of a structural material
 structural materials

•

filler materials
•

Carbon fibre, Kevlar and fibre glass
Honeycomb and foam
bonded together using epoxy resins
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
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
IN THE LONG RUN




Electric car
Increase in petroleum prices
short distance commutation
improvements
THANK YOU