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Power Supply for a Remotely Operated Vehicle (May05-12). Team Members: Jonathan Gettler EE Tai Ong EE Adam White EE Wei Yau EE Client: Scott Morgan Stealth ISR Engineering St. Paul, Minnesota Faculty Advisor: Dr. Venkataramana Ajjarapu
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Power Supply for a Remotely Operated Vehicle (May05-12) Team Members: Jonathan Gettler EE Tai Ong EE Adam White EE Wei Yau EE Client: Scott Morgan Stealth ISR Engineering St. Paul, Minnesota Faculty Advisor: Dr. Venkataramana Ajjarapu Date: April 25th, 2005
Presentation Outline • Adam • Research, Design and Implementation • Other Project Activities • Yau • Resources & Schedules • Closing Materials • Questions • Jonathan • Introduction • Assumptions and Limitations • End-Product • Tai • Team Accomplishments • Approaches and Considerations May05-12
Project Introduction • Remote control plane hobbyists want on-board electronics • Existing power systems do not meet the power requirements • Design a power supply that meets the new needs of hobbyists
Project History Summary • Mechanical and electrical projects in parallel • April 5th mechanical team was more successful than expected • Loosens electrical design constraints Mechanical Design Start End Product Electrical Design
List of Definitions • AGM – Absorbed Glass Mat • PWM – Pulse Width Modulation • UAV – Unmanned Aerial Vehicle May05-12
Acknowledgements • Thanks to Dr. Ajjarapu for investing research dollars into SimPower. • Thanks to Scott Morgan for the personal contributions to the project. May05-12
Problem Statement Alternative electronics onboard UAVs Increased power requirements stress the system Onboard batteries are overcharged and overheated Options for power supplies are limited May05-12
Approach Statement • Design a power supply for large electrical loads • Power supply must be versatile • Increase reliability and life of the batteries May05-12
Operating Environment Extreme temperatures -37°F to 125°F Extreme vibration Shock May05-12
Remote control hobbyists Any person who wants to generate electricity Intended Users May05-12
Intended Uses Provide electric power to remotely operated vehicles Transform rotating mechanical energy into electrical energy May05-12
Assumptions • The gasoline motor will operate between 2,500 RPM and 13,000 RPM • Total load will not draw more than 100 Watts • Rectified generator output voltage will be 3.5-13 Volts DC May05-12
Power Limitations • Output • 3.3 Volts (+.1/-.05V) • 5 Volts (+.2/-.1V) • 12 Volts (+.4/-.2V) • Less than .05 Vrms noise in the output • Batteries must supply the full load for 15 minutes without generator power May05-12
Physical Limitations • The power supply shall be less than 2 pounds • Physical size shall be less than 6”x4”x1” • Emissions shall conform to MIL-STD-704C • Costs shall not exceed $500 May05-12
End Product and Other Deliverables • Prototype mobile power supply • Test results • Specifications manual • Final design report May05-12
Present Accomplishments • Order Parts 100% (completed) • Design 100% (completed) • Research 100% (completed) • Testing 80% (completed) May05-12
Three-phase generator Provided by the client AC to DC rectifier Two choices Construct from scratch Six diodes Circuit board Labor cost Purchase off the shelf Less cost Hobby Airplane Engine 3 Phase Generator 3 Phase Rectifier Boost Voltage Regulator Battery Charger 12V Buck Regulator 5V Buck Regulator Batteries Load Load 3.3V Buck Regulator Load Approaches Considered May05-12
DC to DC step-up converter Switching voltage regulator Light Efficient Transformer Heavy Frequency issues Hobby Airplane Engine 3 Phase Generator 3 Phase Rectifier Boost Voltage Regulator Battery Charger 12V Buck Regulator 5V Buck Regulator Batteries Load Load 3.3V Buck Regulator Load Approaches Considered May05-12
Hobby Airplane Engine 3 Phase Generator 3 Phase Rectifier Boost Voltage Regulator Battery Charger 12V Buck Regulator 5V Buck Regulator Batteries Load Load 3.3V Buck Regulator Load Approaches Considered • Battery charger • MAX1873TEE evaluation kit • Meets all project requirements with an upgrade • Other • No other chargers were capable of handling current requirements within design limitations May05-12
Hobby Airplane Engine 3 Phase Generator 3 Phase Rectifier Boost Voltage Regulator Battery Charger 12V Buck Regulator 5V Buck Regulator Batteries Load Load 3.3V Buck Regulator Load Approaches Considered • Batteries • AGM lead acid • Heavy, not available in small sizes • Nickel Cadmium/Nickel Metal Hydride • Lower capacity than Lithium Ion • Lithium Ion • High capacity • Used for high power applications May05-12
Project Definition Activities Used for small airplane Power on-board electronics May05-12
Research Activities • Project components May05-12
Research Activities: Generator • Experimental setup May05-12
Research Activities: Generator • Voltage vs. generator RPM curve with three phase rectifier May05-12
Research Activities: Step-up Converter • Research components to use in building a step-up switching converter May05-12
Research Activities: Step-up Converter • Research commercially available step-up switching converter • After initially finding none that met the project’s demands, one was stumbled upon • DCDC12/24/160 from Zahn Electronics
Research Activities: Batteries and Charger • Lithium Ion batteries to meet weight and capacity requirements • Maxim charger evaluation kit
Research Activities: Step-down Converter • Linear regulator • Switching regulator May05-12
Design Activities: Step-up Converter • Initially selected components to use in a step-up switching converter • TI, TL5001 PWM control circuit May05-12
Design Activities: Step-up Converter • Later purchased a step-up converter May05-12
#1 #2 #5 #4 #1 #3 Design Activities: Battery Charger • An evaluation kit in the prototype • Evaluation board needed special tweaking May05-12
Design Activities: Step-down Converter • Client decided that only the 12V output was needed • A 12V step-down regulator was purchased May05-12
Tested Vout vs. RPM using a high-speed rotary tool Tested step-up voltage converter Unable to test battery charger due to shipping and other supplier issues Tested ability of batteries to supply rated load Tested the step-down converter’s ability to power 12V load Testing and Modification Activities May05-12
Other Significant Project Activities • Met with client in Eagan, MN • Phone calls • Sampled parts • PSpice simulations of circuit components May05-12
Personal Effort May05-12
Resource Cost May05-12
Total Project Cost Parts and Materials: Without Labor With Labor Project Poster $50.00 $50.00 Project Parts: Generator * (donated by client) donated Rectifier/Booster parts $30.04 $30.04 Battery charger $61.32 $61.32 Batteries $91.80 $91.80 DC/DC boost converter $100.00 $100.00 12 volt regulator $100.00 $100.00 Subtotal $433.16 $433.16 Labor ($10.30 per hour): Gettler, Jonathan $0.00 $2472.00 Ong, Tai $0.00 $1977.60 White, Adam $0.00 $2863.40 Yau, Wei $0.00 $2307.20 Subtotal $0.00 $9620.20 Totals $433.16 $10053.36 May05-12
Project Task Schedule Specification changes Additional lead time on parts May05-12
Project Evaluation May05-12
Commercialization • Potential market • Remote control hobbyists • Production cost $350 • Retail price $700 May05-12
Complete testing of battery charger Increase load handling capability Size and weight reduction of prototype Recommendations for Future Work May05-12
Went well • Team communication • Vision of final product • Desire to finish project • Did not go well • Difference between experimental and expected results of testing • Lack of circuit fabrication experience • Often behind schedule Lessons Learned May05-12
Lessons Learned • Technical knowledge gained • Electrical characteristics of motors • Power electronics design and modeling • Operation of a gas engine for UAV • Datasheet implementation • Non-technical knowledge gained • Public speech • Improved formal documentation and communication skills May05-12
Lessons Learned • What would be done differently • Further define project specifications • More work in the beginning stages • Order parts sooner • Clearly divide tasks among members May05-12
Potential/Encountered risks • Lead time on ordered parts • Loss of stored data • Voltage drop when load is connected • Management of risks • Backup data on engineering storage drive • Increase generator output by changing gear ratio Risk and Risk Management May05-12
Cascading system: generator, rectifier, booster, charger, batteries, and regulator. Provide required 12 volts and 75 watts at output An easy to install and use add-on for remotely operated vehicles that require on-board power electronics Upgrade UAV’s power capabilities, ground/air constant power source Closing Summary May05-12
Questions/Feedback? May05-12