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Detailed Design Review. MSD Project #12441: Thermoelectric Power Pack Lead Software Engineer: Colin McCune (EE) Project Manager: Andrew Phillips (EE) Test Engineer: Lauren Cummings (EE) Cost Engineer: Xiaolong Zhang (EE). Goals of Detailed Design Review.
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Detailed Design Review MSD Project #12441: Thermoelectric Power Pack Lead Software Engineer: Colin McCune (EE) Project Manager: Andrew Phillips (EE) Test Engineer: Lauren Cummings (EE) Cost Engineer: XiaolongZhang (EE)
Goals of Detailed Design Review • Communicate detailed design to P12442 and project guides. • Catch mistakes and overlooked details of the design. • Display feasibility of the design.
Customer Needs Importance Scale: 1 - Low Importance, 2 - Moderate Importance, 3 - High Importance
Engineering Specifications 1-10 Importance Scale: 1 - Low Importance, 2 - Moderate Importance, 3 - High Importance
Functional Decomposition: Maximum Power Point Tracker (MPPT)
Battery • Battery Selection • Given the high storage requirements, relatively high current draw (about 700mA), and low cost requirements the Panasonic LC-R064R5P Lead Acid battery was selected. • The recommended trickle charge current for the battery to achieve a 5 hour charge is 720mA. This is slightly higher than the predicted maximum output current of the MPPT of 670mA. Because of this no current control or disconnect system is needed.
Battery Selections Effect on the System • From the figure below it can be seen that at a discharge rate of 1.125 A the terminal voltage ranges from 5.1V to 6.5V. The power systems will need to be designed to operate across this voltage range.
MPPT Reference Material* Maximum Power Equations MPPT Schematic Results *A maximum power point tracking circuit of thermoelectric generators without digital controllers – Shiho Kim, Sungkyu Cho, Namjae Kim, and Jungyong Park
MPPT Sawtooth Wave Generator Sawtooth generator simulation. Sawtooth generator simulation schematic.
12V Fan Converter Fan converter schematic
System Converter simulation Both input / output current and output voltage become stable after 300 µs. Vary input voltages to 5V, 6V and 7V, output voltages stay the same at 3.3V.
USB Converter Input: 5V to 7V, to account for and voltage fluctuations from the MPPT and the full discharge level of the battery. Output: 5V +/- 5% per USB specifications, the output current will be 700mA max to allow for a maximum draw of 500ma for the USB, and an additional 200mA draw for the analog circuitry.
USB Operation at Nominal Input and 1A Output The input current (above) and output voltage and current (below) with a 6V input and a load current of 1A.
Output Behavior With A Varying Input The output voltage and current with an input voltage of 5V, 6V, and 7V.
Enclosure Concept Top View Side View
Sample Test Document • What is being tested and why • Equipment • List of required equipment • The settings of the required equipment • Procedure • What is being measured? • How is it being measured? • Result table • Step number • What is being measured? • What is the expected value? • What is the measured value? • Pass/Fail and why • Did the device pass the test? • Defend the decision.
Risks 1-6 Importance Scale: 1 - Low, 2 - Moderate, 3 - High