Portable Li-Ion Battery Charging System Using Wind Power. Shawn Ocorr Trevor Smith Danielle Allen John VanDeLinde

Transcription

1 Portable Li-Ion Battery Charging System Using Wind Power Shawn Ocorr Trevor Smith Danielle Allen John VanDeLinde EE EE EE ME

2 PROJECT DESCRIPTION Design and build a portable energy system that will charge a single cell lithium ion battery from a renewable source. Batteries and charging system are to be used for the WOCCS wireless transceiver applications. Primary design parameters for this project focused on the needs of the WOCCS project teams. Design considerations were also in place to reflect the military applications of Harris RF Sponsored by Harris RF. The BIG Picture KEY CUSTOMER NEEDS 1. Portable 2. Supply power to WOCCS 3. Reliable 4. Obtain energy from the environment P11401

3 KEY ENGINEERING SPECS Engineering Spec Customer Need Ideal Value Units Net weight Portable 30 lbs System volume Portable 7 ft 3 Power Supply Power 1.0 Watts Voltage Supply Power 3.2 Volts Ripple Supply Power 0.5 % Battery discharge time Supply Power 8 Hours Compatibility Reliable Yes Binary Achieve power Energy from environment Watts

4 WOCCS POWER BOARD SUCESSES Functional board submitted for system integration January 21, 2011 Provides adequate power for midrange and long-range RF transmission Functional connection for Test Bench testing CHALLENGES Misaligned switch/power connector in 1 st iteration (expected) Revised board layout during 2 nd iteration Loose battery during housing team drop test Broken switch during drop test 8 power boards completed Load Resistance (Ohm) Voltage (V) (W) Measured Value 10Ω V Watts Peak-To-Peak Voltage (V) Average Voltage (V) (%) Measured Value V V %

5 Disassembled Portable Charging System Disassembled Charging System Volume Length inches Width inches Height 4 inches System Volume in ft 3 Component Weight (lbs) Turbine Blades 4.0 Hub with nuts and bolts 1.5 Tail assembly 4.5 Cab les with flange, caribeeners, and spikes Galvanized Pipe #1 with coupling (bottom half of stand) Galvanized Pipe #2 with coupling and 3 pipe ( top half of stand) 4.5 Electronics Box with Charge Circuitry and 20 gage generator wire 0.5 Generator with mount 2.0 Total 24 Assembled

6 Charging System Test Results VIDEO: low wind speed startup VIDEO: stopping the windmill Challenges Temperature operating range removed NTC resistor Efficiency may be effected by cold temperatures generator dependent bipolar configuration limits Amps/phase Data Set Average Wind Speed (m/s) Generator Voltage (V) Voltage Across Current Sense Resistor (0.05Ω) Generator Current (I) Power of Generator (W) Power in Wind (W) Efficiency % %

7 CHARGE CIRCUIT: Test Results Post-Rectification Battery IC Input Voltage (V) Current (A) Power (W) Voltage (V) Current (A) Power (W) Efficiency Successes Handles dynamic generator output voltage range Efficiency > 90% Peak tested operating temperature of 83 F Safely charges lithium ion battery CC/CV rate critical

8 BATTERY: Charging and Discharging PHASE I PHASE II Results 8 hour charge test resulted in battery voltage increase 0.9V 1/30/ V initial to 3.63V after 2.5 hrs 2/01/ V initial to 3.78V after 5.5 hrs Charge deposited is important Most time spent in charging Phase II Phase 1: min Phase 2: min Time (Minutes) Voltage (V) Time (Minutes) The system passes the charging test if the voltage across the battery reaches 4.2 V (or fluctuates above 3.7 V) before or at the 480 minute mark. Voltage (V

9 System Testing Summary P11401: Preliminary Test Plan Specs Met Net weight System volume Sound pressure level Power: rated, peak Voltage: rated, peak Ripple Li-Ion battery charge time Li-Ion battery discharge time Battery quantity Energy storage efficiency Drop impact Operating temperature range Compatible with P11201 test bench Component surface operating temperature RoHS compliance Specs Not Met Achieve power > Watt-hr Measured Watts instantaneous Test # Engineering Spec Verification Method Fail Criteria 1 Net weight Measurement > 30 lbs 2 System volume Measurement > 7 cubic feet 3 System sound pressure level (audible noise) Measurement > 90 db 4 Power: rated, peak Measurement < 1 Watts 5 Voltage: rated, peak Measurement < 3.2 Volts 6 Ripple: % of battery voltage Measurement > 0.5% 7 Li-Ion Battery charge time Measurement > 8 hours 8 Li-Ion Battery discharge time Measurement < 6 hours 9 Battery Quantity during charging Observation Greater than 1 10 Energy generation efficiency Analysis < 15 % 11 Energy storage efficiency Analysis < 50 % 12 Withstand drop impact Measurement < 5 feet 13 Operating temperature range Measurement > 32 F or > 100 F 14 Compatible with P11201 test bench Demonstration components Not Compatible 15 Component surface operating temperature Measurement > 140 F 16 RoHS Compliant with hazardous Not all parts are Analysis substances laws compliant 17 Achieve power Demonstration < Watt-hr Energy generation efficiency 11.82% < 15%

10 Recommendations for Future Work 1. Larger generator 2. Higher power output 3. Charge multiple batteries 4. Larger batteries or battery pack 5. Microcontroller IC Entire user interface - control voltage configurations at low/high wind speeds 1. Digital voltage display on charge circuit 2. Gear head device for higher generator RPM 3. Integration with solar IMAGE SOURCES

11 QUESTIONS?