Intelligent Solar Battery Charger

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Intelligent Solar Battery Charger

• Ricky White 2004
• Supervisor Ken Mercer

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Overview

• Theory / why develop this system
• The Control Algorithm
• The power control hardware
• The Embedded System
• The Windows Software
• Future Work

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System Overview
Data Logging and configuration
Intelligent Solar Battery Charger
Solar Panel(s)
Load or other charging source
Battery
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Design ConsiderationsSolar Panel Characteristics
VI PV75 1000W/m2 _at_ 25?C
P PV75 1000W/m2 _at_ 25?C
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Battery Charging supportfor Lead Acid Batteries

• Several charging modes
• Absorption
• Normal charging mode at 14.4V
• Float
• Used once battery is fully charged
• float at 13.8V typically,
• Maintain charge in battery
• Equalisation
• Slight over charge
• Equalise individual cells by ensuring all are
  fully charged
• Force cells to boil to stir them up
• Charging Implemented as part of the regulator
  software module.

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Peak power Tracking
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Peak power Tracking
Impedance matching Switch Mode Converter
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The Control Algorithm
P for Kyocera PV75 Solar Panel,1000W/m2 _at_ 25degC

• Peak Tracking (dither)
• Asymmetric slope
• Micro to Converter
• Simulated in Matlab

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Block Diagram of Controller
Cygnal C8051F020 Microcontroller
Step down / up Switch Mode converter
Power Measurement MAX472
Power Measurement MAX472
Power Measurement MAX472
Solar Panel
Load
Battery
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Block Diagram of Controller
MAX 472 High Side Current Measurement
Cygnal C8051F020 Microcontroller
5mO
12V Source
To Load
50O
50O

• Very low shunt R
• Low Power
• No Offset Issues
• Bidirectional
• Compact

MAX 472
Vout
Step down / up Switch Mode converter
2KO
Power Measurement MAX472
Power Measurement MAX472
Power Measurement MAX472
0V
Solar Panel
Load
Battery
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Switch Mode Converter Design
Vout
Vin
Mode Q1 Q2 Q3 Q4 Buck
On Off Boost On Off
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Switch Mode ConverterStep Down, phase 1
Switch (On)
On
Vout
Vin
Off
Synchronous Rectifier (Off)
Mode Q1 Q2 Q3 Q4 Buck
On Off Boost On Off
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Switch Mode ConverterStep Down, phase 2
Switch (Off)
On
Vout
Vin
Off
Synchronous Rectifier (On)
Mode Q1 Q2 Q3 Q4 Buck
On Off Boost On Off
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Switch Mode ConverterStep Up, phase 1
Synchronous Rectifier (Off)
On
Vout
Vin
Off
Switch (On)
Mode Q1 Q2 Q3 Q4 Buck
On Off Boost On Off
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Switch Mode ConverterStep Up, phase 2
Synchronous Rectifier (On)
On
Vout
Vin
Off
Switch (Off)
Mode Q1 Q2 Q3 Q4 Buck
On Off Boost On Off
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The Prototype
Front Panel board
Microprocessor and support
Power Converter and Power Measurement
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The Controller Software
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The Windows side
Control / Configuration Application
ODBC interface DLL
Comport Sharing DLL and EXE
Data collection / polling NT Service

• All 4 blocks developed as part of project

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Screenshots
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Future Work

• Completion of embedded software
• Completion of Windows software
• Commercialisation
• Other Uses

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Possible Commercialisation

• Prototype cost lt 300
• Replaces basic regulator offsetting cost
• Can be adapted to different uses
• Product development for enclosure
• Some more software implementation needed
• Optomisation of Efficiency

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Summary

• An embedded hardware controller incorporating a
  switch mode converter has been implemented to
  optomise power transfer from solar panel to
  battery
• The hardware has been tested, with the software
  algorithm needing tuning
• The PC interface and communications Software has
  been developed along with a basic GUI
• System Integration

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Questions?