Solar Powered Battery Charger Kevin McDowall, Joshua Ivaldi, Muhammad Mustaqeem Khatri, and Alfredo...
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Transcript of Solar Powered Battery Charger Kevin McDowall, Joshua Ivaldi, Muhammad Mustaqeem Khatri, and Alfredo...
Solar Powered Battery Charger
Kevin McDowall, Joshua Ivaldi, Muhammad Mustaqeem Khatri, and Alfredo Elias
Department of Electrical and Computer Engineering
University of Connecticut
Advisor: Dr. Sung Yeul Park
Date 19 April 2013
Motivation
Specifications
Buck Converter Topology
Sensors
Microcontroller
Algorithm
Design Details
Results
Cost
Conclusion
Questions
Outline
Motivation
Decided to leave IFEC work and start new work on Solar Battery Charger for better design experience
Design topologies are similar so will help us in transition
Buck Converter Topology
24V ≤ Vin ≤ 48V Vout < 13.8V Buck converter is a
step-down DC to DC converter
Therefore, buck converter topology was chosen
Block Diagram
Sensors
Need sensors for feedback purposes The input voltage and current are monitored, as
is the output voltage and current. This is done with current sensors and
operational amplifier comparators.
Microcontroller Board
The microcontroller chip is TMS320F28335, coded in C++.
The board monitors input current, input voltage, output current, output voltage and current battery charge.
Control Algorithms
The control board is coded to operate three different algorithms; Constant Current, Constant Voltage and Maximum Power Point tracking.
Constant Current – The first stage of the charging process. Will charge battery to about 95% completion
Constant Voltage
The second stage of the charging process. The battery is supplied 13V across its terminals until the full charge is reached.
MPPT
Maximum Power Point Tracking (MPPT) – Sunlight conditions change, so there is need to constantly calculate maximum power available from PV panel
Design details: Power Circuit Schematic
Isolator for signal transfer
Design details: Voltage Supply Schematic
12 Volt Supply
5 Volt Supply
Design details: Sensor Schematic
Current Sensor
Comparator
Comparator
PCB Layout
• Altium Designer• 4 layers
• Top Layer• 5V Layer• 3.3V Layer• GND Layer
Results
• Slight errors in sensor readings
• Modification required in the gate driver
• Able to run all algorithms successfully
Board Cost
The total cost to produce the power board is: $162.06
Cost of control board: $102.80 The cost of a 220W solar panel is: ~$350
Conclusion and Learning Experience
• We have achieved all specification and design requirements
• Learned:
• PV Model
• Battery Charging algorithms
• Design of schematic and PCB board
• Able to combine knowledge from courses such as microcontrollers, power electronics, and digital control systems
Questions???