Transcript Final Presentation - ECE Senior Design

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
Outline
Motivation
Specifications
Buck Converter Topology
Sensors
Microcontroller
Algorithm
Design Details
Results
Cost
Conclusion
Questions
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
Comparator
Comparator
Current Sensor
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???