Solar Array

1
Solar Array Maximum Power Point Tracker Group

• Senior Design Project 2003
• Stephanie Chin
• Jeanell Gadson
• Katie Nordstrom
• Advisor Karen Panetta

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What is a Maximum Power Point Tracker?

• The Maximum Power Point Tracker (MPPT) optimizes
  the amount of power obtained from the
  photovoltaic array used to charge the electrical
  power supply

Why Design a MPPT?

• Our design is customized to meet the varying
  conditions of solar car racing, i.e. shadows,
  over-sun exposure, weather conditions, etc.

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Basic Design

• The maximum power tracker unit includes the
  following components
• Solar Array
• Power Supply
• PIC Microcontroller
• Analog to Digital Digital to Analog Converters
  (ADCs and DACs)
• Pulse Width Modulator (PWM)
• Field Effect Transistor (FET)
• Protection Diodes
• DC/DC Converters

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Solar Array

• A solar cell is a semiconductor device that
  absorbs the sunlight and converts it into
  electrical energy
• Power Supply
• The solar array charges 4 batteries at a time

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PIC Microcontroller

• Operates the DACs and ADCs
• Computes the power point of the array according
  to the I-V curve.
• Regulates the Integrated Circuits (ICs)

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Converters

• ADCs
• Built into PIC
• Changes the analog output of the solar
  array into a digital signal
• DACs
• Translates the digital output of the PIC into
  an analog signal for the PWM

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Pulse Width Modulator (PWM)

• Controls the FET

Field Effect Transistor (FET)

• Our Light Switch
• Prevents overcharging of the batteries
• Determines the current paths between the
  solar array, power supply, and ground

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Protection Diodes

• Prevent the current from flowing back into the
  solar array

DC/DC Converters

• Boost and Buck Converters which power the ADCs,
  DACs, PIC, and PWM

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System Specifications

• MPPT can handle Solar Array Input Voltage range
  0-200v and max input current of 10A.
• The DC/DC Buck Converter steps down the Array
  voltage to 5v to power the PIC, DACs, and RS-232.
  Similarly, the DC/DC Boost Converter steps up
  the 5v input to 12v to power the PWM.