Solar Array Maximum Power Point Tracker Group Senior

Solar Array & Maximum Power Point Tracker Group Senior Design Project 2003 Stephanie Chin Jeanell Gadson Katie Nordstrom Advisor: Karen Panetta

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.

Basic Design The maximum power tracker unit includes the following components: n n n n 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

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

PIC Microcontroller n n Operates the DACs and ADCs Computes the power point of the array accordin to the I-V curve. n Regulates the Integrated Circuits (ICs)

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

Pulse Width Modulator (PWM) n Controls the FET Field Effect Transistor (FET) n Our “Light Switch” n Prevents overcharging of the batteries n Determines the current paths between the solar array, power supply, and ground

Protection Diodes n Prevent the current from flowing back into the solar array DC/DC Converters n Boost and Buck Converters which power the ADCs, DACs, PIC, and PWM

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