Multiple-Output, Variable-Output DC Power Supply - Phase 2 May 04-08

Multiple-Output, Variable-Output Multiple-Output, Variable-Output DC Power Supply - Phase 2DC Power Supply - Phase 2

May 04-08 May 04-08

http://seniord.ee.iastate.edu/may0408/

Multiple-Output, Variable-Output DC Power SupplyMultiple-Output, Variable-Output DC Power Supply

ClientClient Senior DesignSenior Design

Dr. LamontDr. Lamont Prof PattersonProf Patterson

AdvisorsAdvisors Dr. PotterDr. Potter Dr. AjjarapuDr. Ajjarapu

Team MembersTeam Members Benjamin Voetberg, EEBenjamin Voetberg, EE Fares Karadsheh, EEFares Karadsheh, EE Trung Nguyen, EETrung Nguyen, EE Darrell Long, EEDarrell Long, EE

Senior Design :: May 04-08Senior Design :: May 04-08

OverviewOverview Project objectives & guidelinesProject objectives & guidelines

Create low cost dc power supplyCreate low cost dc power supply Range of voltagesRange of voltages

Design ApproachDesign Approach ac to dcac to dc

End ResultEnd Result What the team accomplishedWhat the team accomplished

BudgetBudget Price comparisonPrice comparison Layout of costLayout of cost

ScheduleSchedule Project EvaluationProject Evaluation Risk and Risk ManagementRisk and Risk Management

Senior Design Senior Design :::: May 04-08 May 04-08

Project Objectives & GuidelinesProject Objectives & Guidelines

The project is to design a DC power supply that provides The project is to design a DC power supply that provides

power at various voltagespower at various voltages

+/- voltages will include 5V, 6V, 12V, 18V+/- voltages will include 5V, 6V, 12V, 18V

+/common voltages will include 1.5V, 3.0V, 3.2V, 3.3V, +/common voltages will include 1.5V, 3.0V, 3.2V, 3.3V,

4.5V, 5V, 6V, 7.5V, 9V, 12V, 15V, 18V, 24V 4.5V, 5V, 6V, 7.5V, 9V, 12V, 15V, 18V, 24V

Voltmeter and Ammeter to display output valuesVoltmeter and Ammeter to display output values

Between 2 to 4 output terminals.Between 2 to 4 output terminals.


Project Objectives and Project Objectives and Guidelines Cont.Guidelines Cont.

Operating EnvironmentOperating Environment Indoor use for senior design projectsIndoor use for senior design projects

Intended users/usesIntended users/uses Students enrolled in EE/CprE senior designStudents enrolled in EE/CprE senior design Possibility for use in freshman and sophomore level Possibility for use in freshman and sophomore level

labslabs Used to test senior design projects that require DC Used to test senior design projects that require DC

voltagevoltage Assumptions/LimitationsAssumptions/Limitations

Powered by a 120V, 60Hz wall outletPowered by a 120V, 60Hz wall outlet +/- 1% ripple output voltage+/- 1% ripple output voltage Function with +/- 5% of wall outlet voltageFunction with +/- 5% of wall outlet voltage Output current not to exceed 1A on each terminal Output current not to exceed 1A on each terminal


Design Approach Definitions Design Approach Definitions

PWM : Pulse Width Modulation PWM : Pulse Width Modulation

Duty Ratio (D) : Time ON divided Duty Ratio (D) : Time ON divided by the total time by the total time

Lm : Magnetizing Inductance of a Lm : Magnetizing Inductance of a transformer transformer

For the simulation, 2 choice:For the simulation, 2 choice:

Pspice: Available and have a lot of Pspice: Available and have a lot of partsparts

Electronic Work Bench : Easy and Electronic Work Bench : Easy and more visual more visual


Sample from the simulation

Electronic Work Bench was used to simulate the design

Design Approach Buck ConverterDesign Approach Buck Converter

Convert ac to dc using Convert ac to dc using bridge rectifierbridge rectifier

Buck converter is used to Buck converter is used to vary the voltage to get vary the voltage to get desired voltage outputdesired voltage output

Buck converter outputBuck converter outputVo=Vs*DVo=Vs*D

Buck converter diagram

Simple ac/dc conversion

Design Approach Flyback Design Approach Flyback ConverterConverter

Not able to make 1.5-24 Not able to make 1.5-24 volts directly from 120 Vvolts directly from 120 V

Use a flyback converterUse a flyback converter

Flyback converter output Flyback converter output equationequation

Vo=Vs(D/(1-D)) N2/N1Vo=Vs(D/(1-D)) N2/N1


Design Approach PWMDesign Approach PWM Output equations:Output equations:

Vo=Vs(D/(1-D)) N2/N1 Vo=Vs(D/(1-D)) N2/N1 (Flyback)(Flyback)

Vo=Vs*D ( Buck )Vo=Vs*D ( Buck )

PWM : Generate a PWM : Generate a square wave. square wave. (see figure)(see figure)

Trig.sourceComparator


The Reason behind using Flyback then a The Reason behind using Flyback then a ____buck converter is to create an buck converter is to create an isolation.isolation.

Design Approach TakenDesign Approach Taken

A commercial power supply to replaceA commercial power supply to replace bridge rectifierbridge rectifier flyback converter.flyback converter.

Power supply eliminates problemsPower supply eliminates problems Current and the voltage regulationCurrent and the voltage regulation Difficulty finding transformerDifficulty finding transformer Saved timeSaved time

Even with changes still functions as the Even with changes still functions as the simulationsimulation

Buck converter still used to vary voltage to get Buck converter still used to vary voltage to get desired outputdesired output


The new design The new design


Power Supply

120 VAC

Wall outlet 48VDC

Fixed Buck Converter

High Freq. Switch

TL499ACD

25VDCVariable Outputs

Variable Buck Converter

End Product OptionsEnd Product Options

# of +/- terminals

# of + terminals

Meters

Option #1 1 1AmmeterVoltmeter



Client wants for power supply

Low cost system

Useful to senior design teams

Portable Power Supply


Commercial Power SupplyCommercial Power Supply

Astrodyne ® Power SupplyAstrodyne ® Power Supply Regulated OutputRegulated Output 85-265 VAC input85-265 VAC input Overload Voltage protectionOverload Voltage protection Short Circuit ProtectionShort Circuit Protection EMI FilterEMI Filter


Fixed Buck ConverterFixed Buck Converter Switch componentsSwitch components

Motorola SG3527A Pulse Width Modulator Control CircuitMotorola SG3527A Pulse Width Modulator Control Circuit

Fixed duty ratio, 44 VDC to 25 VDCFixed duty ratio, 44 VDC to 25 VDC

Sends square wave to MOSFET DRIVERSends square wave to MOSFET DRIVER

Maxim MA4428 Dual High-speed 1.5A MOSFET DriverMaxim MA4428 Dual High-speed 1.5A MOSFET Driver Drivers both a N-channel and P-channel MOSFET to achieve Drivers both a N-channel and P-channel MOSFET to achieve

the desired switching speedthe desired switching speed

Texas Instruments TL499A circuitTexas Instruments TL499A circuitWide-Range Power-Supply Controllers

R1, R2, R3 create a R1, R2, R3 create a comparison voltagecomparison voltage

Voltage varied by changing Voltage varied by changing potentiometerpotentiometer

Minimum output voltage is Minimum output voltage is 2.5 volts.2.5 volts.

Maximum output voltage is Maximum output voltage is 24 volts24 volts

Digital DisplayDigital Display

Maxim ICL7107 3 1/2 Maxim ICL7107 3 1/2 Digit A/D Converter Digit A/D Converter

Connected across the Connected across the outputoutput

Displays output Displays output voltage to 1/10 voltage to 1/10 accuracyaccuracy

2 double digit 7 2 double digit 7 segment LED displayssegment LED displays

Future Work RecommendationsFuture Work Recommendations

A phase to finalize the projectA phase to finalize the project Necessary future workNecessary future work

Negative voltagesNegative voltages Voltage regulationVoltage regulation Circuit protectionCircuit protection

Other future workOther future work Variable currentVariable current Voltage zero at start upVoltage zero at start up Auto zeroing voltmeterAuto zeroing voltmeter


Financial ComparisonFinancial Comparison


Agilent 3631a triple output power supplyAgilent 3631a triple output power supply 80 watts80 watts ++ 25 V at 1 A 25 V at 1 A +6 V at 6 A+6 V at 6 A $ 1200$ 1200

Proam universal ac-dc adaptorProam universal ac-dc adaptor 9 watts9 watts + 1.5, 3, 4.5, 6, 7.5, 9, 12 V at .5 A+ 1.5, 3, 4.5, 6, 7.5, 9, 12 V at .5 A $ 9.00$ 9.00

Our design nowOur design now 24 watts24 watts 2.5 to 24 V at 1 A2.5 to 24 V at 1 A $ 120$ 120

Personal Time CommitmentPersonal Time Commitment


Paper work

Research Design Construction Total

Darrel Long 25 41 42 24 134

Fares Karadsheh

20 48 47 14 131

Trung Nguyen

22 41 43 24 132

Benjamin Voetberg

25 51 45 14 137

Total 90 184 195 65 534

First Semester ScheduleFirst Semester Schedule


Second Semester ScheduleSecond Semester Schedule


Project EvaluationProject Evaluation Identify possible designs to implement, completed Identify possible designs to implement, completed and choose one and choose one

Design hardwareDesign hardware completed completed

Hardware specificationsHardware specifications completed completed

Circuit simulationsCircuit simulations completed completed

Test hardwareTest hardware almost almost complete complete

DocumentationDocumentation completed completed


Lessons LearnedLessons Learned What went wellWhat went well

CommunicationCommunication Within the teamWithin the team With company representativesWith company representatives

TeamworkTeamwork What didn’t go wellWhat didn’t go well

Unspecific project, time constraint for meeting with Unspecific project, time constraint for meeting with clientsclients

Simulation of the circuitSimulation of the circuit Hardware implementationHardware implementation

Technical knowledge gainedTechnical knowledge gained Simulation experienced gainedSimulation experienced gained Power electronics knowledgePower electronics knowledge


Risk and Risk ManagementRisk and Risk Management Anticipated risksAnticipated risks

Team schedulingTeam scheduling Loss of team member, advisor, or clientsLoss of team member, advisor, or clients

Unanticipated risksUnanticipated risks Simulation complicationsSimulation complications Hardware implementationHardware implementation Unable to use certain designs because of costUnable to use certain designs because of cost


Closing SummaryClosing Summary Variable dc output of 2.5 to 24 voltsVariable dc output of 2.5 to 24 volts

Meets client specificsMeets client specifics Provides extra voltage valuesProvides extra voltage values

Digital voltmeterDigital voltmeter Accurately provides output voltageAccurately provides output voltage

Design is a solid base to further expandDesign is a solid base to further expand Negative voltagesNegative voltages Circuit protectionCircuit protection Voltage regulationVoltage regulation


Questions?Questions?


Documents

Multiple-Output, Variable-Output DC Power Supply - Phase 2 May 04-08