Download Final Report - Senior Design

Table of Contents
1. Introduction Material ................................................................................................................................... 1
1.1 Executive Summary ................................................................................................................................ 1
1.2 Acknowledgements ................................................................................................................................. 1
1.3 Problem Statement ................................................................................................................................. 1
1.4 Potential solution .................................................................................................................................... 2
1.5 Operating Environment ......................................................................................................................... 2
1.6 Intended Users ........................................................................................................................................ 2
1.7 Intended Uses .......................................................................................................................................... 2
1.9 Market Survey .......................................................................................................................................... 2
1.10 Intellectual Property and Legal Considerations................................................................................ 3
2. Approach ....................................................................................................................................................... 4
2.1 Concept Sketch ....................................................................................................................................... 4
2.2 System Block Diagram ........................................................................................................................... 4
2.3 Functional Requirements ....................................................................................................................... 5
2.4 Non-functional Requirements .............................................................................................................. 5
2.5 Assumptions and Limitations ............................................................................................................... 5
2.6 Deliverables.............................................................................................................................................. 6
2.7 Safety Considerations ............................................................................................................................. 6
3 Design, Implementation & Testing.............................................................................................................. 7
3.1 Design ....................................................................................................................................................... 7
3.1.1 Power Inputs .................................................................................................................................... 7
3.1.2 MPPT ................................................................................................................................................ 7
3.1.2.1 Li-ion Charging Cycle .................................................................................................................. 9
3.1.3 Microprocessor ..............................................................................................................................10
3.1.3.1 VCC and VSS..............................................................................................................................10
3.1.3.2 Voltage Senses ............................................................................................................................11
3.1.3.3 Low-side Current Sense ............................................................................................................12
3.1.3.4 High-side Current Sense ...........................................................................................................13
3.1.3.5 UART Output ............................................................................................................................14
3.1.4 Charging Circuitry .........................................................................................................................14
3.1.5 Batteries ..........................................................................................................................................15
3.1.6 Buck Converter..............................................................................................................................15
3.2 Implementation .....................................................................................................................................17
3.2.1 Initial Buck Converter ..................................................................................................................17