solar car electrical system overview. basic system diagram solar array battery motor maximum...

Solar Car Electrical System Overview

Basic System Diagram

Solar Array

Battery

Motor

Maximum PowerPoint

Trackers

Battery Management

System

Motor Controller

DC/DC Converter

Driver Display

Lights

Telemetry Radio

Rear View Camera

Vehicle Control and Data Acquisition

Computer

CAN Bus 1

CAN Bus 2

HV Bus

LV Bus

Solar Array

• 6m2 SunPower B30 monocrystalline silicon cells

• Split into 4 sub-arrays• Specialist encapsulation, increasing efficiency

by ~4%• 22% efficient overall• 1.3kW measured max power output• Value: £22,500

Maximum PowerPoint Trackers

• Also known as MPPTs• Built to custom specification by

Drivetek• Essentially a DC/DC converter,

converting array voltage to HV bus voltage

• 98% efficient• 4 MPPTs, one to interface with each of

the sub-arrays of solar cells

Motor & Motor Controller

• 1.8kW CSIRO 3-phase brushless DC hub motor

• 98% efficient• 4kW peak power• Custom designed hub, machined by

Cambridge Precision• Value: £18,000• Motor Controller: Tritium

Wavesculptor• Value: £5,500

Battery

• LiFePO4 chemistry• Limited by World Solar Challenge regulations

to 40kgs• Capacity of over 4kWhr• 125V nominal• Custom BMS with CAN interface module

Control and Data Acquisition

• Entire solution provided by National Instruments CompactRIO

• Interfaces with CAN busses• Driver inputs and vehicle

instrumentation connected directly to modules

• Telemetry radio connected to serial output port

Control and Data Acquisition

• High-speed control loop run in FPGA, providing fast, reliable response to driver inputs

• Background loop run in Real-Time Controller• Sets maximum allowable currents• Determines preferred speed for cruise control• Logs all data• Selects data to be transmitted over telemetry, to

minimise power consumption