Solar Powered Golf Cart

Group 9Jake BettisJacob KruegerMatthew RolandMatt Tourtelot

With Support from:

Motivation

Rapid growth in renewable energy, such as solar power, has caused a huge increase in the demand for engineers that know how to utilize these alternative sources of energy

With our project we are able to design and create an environmentally friendly vehicle while gaining first-hand knowledge and experience in a growing industry

Goals

To create an energy efficient golf cart that is capable of running on solar power and external outlet. A touch-screen display will give the user options for different energy modes, navigational help, and status of golf cart

Objectives Harvest energy from sunlight to power electric motor and onboard

electronic systems Three modes of energy operations

o standard, max performance, max efficiency Power monitoring system to display battery levels and check for battery

storage defects User touch-screen display

o Provides navigational map interfaceo Allows users to change cart’s operating modeo Displays cart’s current speed, current mode, and battery charge

remaining.

Objectives

Energy Modes Standard mode: A normal acceleration ramp will be used for this setting Max Performance: The motor controller will ramp up the speed almost

instantly Max Efficiency: The motor controller will ramp up the speed very slowly

The biggest power drain on the cart is acceleration so this was controlled to save energy

Specifications and Requirements

1. Must have a top speed of at least 15 mph2. Must have 3 modes of operation which can be controlled by

user3. Must run off of a 36V or 48V battery storage bank4. Batteries must be able to charge from solar panels or wall outlet5. Must have a touch-screen display for user information6. Must provide navigational aid to user7. Must provide power mode options and current speed

Budget

Part Estimated Cost Actual Cost

Motor Controller $600 $550

Batteries $600 $550

Charge Controller $150 $100

Microcontroller(s) $120 $140

Touch-Screen Display $120 $70

Sensors $150 $50

Misc. $100 $400

PCB Fabrication $0 $265

Total $1,840 $2,125

Power System Components

Solar Panels and Wall Outleto provide power for motor and onboard electronics

Solar Charge Controller o Regulate power inputs from solar panels the batterieso Implement MPPT algorithm to keep from overcharging and

damaging the batteries

Battery Banko provides 36V battery supply

Power System Overview

Wall Outlet

Solar PanelsSolar Charge

Controller

Battery Bank Motor+36 V Power

Board

3.3VDC/DC

Regulator

Motor Controller

5VDC/DC

Regulator Oddroid C1

Touchscreen Display

Solar Panel Electrical Specs

Project design implements two panels connected in series.

Unit Quantity

Maximum Power Pmax 250 W

Voltage at maximum power point Vmpp

30.7 V

Current at maximum power point Impp 8.15 A

Open Circuit Voltage Voc 37.7 V

Open Circuit Current Ioc 8.72 A

Operating Temperature -40° C to +85° C*Specs are based on single panel at standard test conditions

Battery Supply

36V battery bank that will power motor and all onboard electronics

Flooded lead-acid, deep cycle batterieso Able to withstand deep discharge cycles

and have a long lifetime At 25A output batteries can last for 474

minutes, and 122 minutes at 75A

Battery Specs

Unit Quantity

Voltage 6 V

Amp hours (20 hour rate) 232 Ah

Minutes at 75 Amps 122 min.

Minutes at 56 Amps 179 min.

Minutes at 25 Amps 474 min.

Wet Weight Lbs. 62 Lbs.

U.S. 2200-XC2 Deep Cycle Lead-Acid battery

Battery Specs

Rate of discharge Batteries need to

be able to operate for as long as possible while supporting different energy modes

Consider current vs. discharge time

Charge Controller Goal is to regulate voltage and current

from solar panels to the battery, to prevent overcharging

Will implement a maximum power point tracking (MPPT) algorithm Finds the maximum power point on

the I/V curve and tracks that point as sunlight conditions vary

Works as DC to DC converter Outputs GPS coordinate information

to the microcomputer Design is based off of Texas Instruments

TIDA-00120

Solar Charge Controller Schematic

• Block diagram of Solar Charge Controller System

• SM72295: Photovoltaic Full Bridge Driver

• INA271 : voltage output, current sense amplifier

Solar Charge Controller Schematic

• MSP430F5132: ultra-low power mixed signal microcontroller

• LM5019: 100V buck regulator

• TLV70433: low dropout regulator (LDO)

MPPT Algorithm

• Perturb and Observe• Method is to modify the

operating voltage or current from PV panel until you obtain maximum power from it

Touchscreen Display System Objectives

Provide users with straightforward navigation around the UCF campus via GPS locationo Navigational map will be interactive and contain

certain customizable features Display the golf cart’s current speed and operating

mode Allow users to easily switch between available cart

operating modes

Touchscreen Display System Components

Microcomputer Provides platform for Android Operating System Processes GPS and display signal input and output

GPS PCB module Outputs GPS coordinate information to the

microcomputer Touchscreen Display

Provides user with display of the Android Application Supplies microcomputer with user input

Touchscreen Display Data Flow Chart

Microcomputer

ODROID C1 Raspberry Pi

Market Price $38 $35

CPU 1500 MHz Cortex-A5

700 MHz ARM1176JZF-S

Video Outputs Micro-HDMI HDMI and composite video

Power Source 0.8mm x 2.5mm 5V jack

5V via MicroUSB or GPIO header

ODROID C1 Features Implemented

Android Runtime Environment compatibilityo Allows for the creation of a specialized Android

Applicationo Easy Debugging

HDMI video signal outputo Allows video signal to be sent to the touch screen

display while freeing up the USB input for the touch screen’s user input signals

Touchscreen Display

HDMI 4 Pi: 5” Display w/ Touch and Mini Driver - 800x480 HDMI

Tekit 619AHT 7” LCD Monitor

Market Price $79.95 $179.98

Screen Size 4.8” x 3.0” 8.23” x 5.7”

Resolution 800 x 480 800 x 480

Display Ratio 16:10 16:9

Contrast 300:1 500:1

MTK3339 GPS Module

Sends GPS data pertaining to the current user position to the ODROID C1

10 Hz update frequency Accurate to about 3

meters

GPS Module - PCB Schematic

GPS Module - PCB Design

GPS Module - PCB

Android Application Development

Developed within the Eclipse IDE using the latest Android SDK

Many other inherent features of Java are used throughout the application design

Tested for accuracy and reliability on every design prototype iteration

Android Application Class Diagram

UCF EzNAV Main Menu

Very simple, intuitive interface

The only screen that gives access to every created class

Each button takes the user to a new screen within the app

Navigate Screen

Interactive Google Maps Fragment

“My Location” button and functionality

Map markers for reference and building information

License key for Google Maps API obtained through Google Inc.

Cart Status Screen

Features updating data fields for cart informationo Uses signals from

the Motor Controller and GPS module to generate values

Interface buttons that allow users to change the cart’s operating mode

Motor Controller Overview

Pre-charge circuit prevents inrush current to motor controller

Potentiometer pedal provides a voltage from 1.45-1.92

Direction switch removes need for H-Bridge

Power Board

Power Board Schematic

High current MOSFET’s On-Resistance of 1.45mΩ

Capacitance Flyback diodes

Motor Controller Logic

Pedal

Potentiometer over ITS

Modes of Operation

Mode determined by user from touch screen

Progress

Testing

Prototyping

Research

Design

Total

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Chart Title

Questions?