SYSTEM LEVEL DESIGN REVIEW

P12026: Transcutaneous Power Transmission

Team MembersNooreldin Amer

Michael CarozzoniWilliam Chan

Naveen GeorgeDevin Prescott

Paul Slagle

Outline

Project Description Review of Needs, Specifications Functional Decomposition Basic Calculations and Simulations Concept design Component selection Review of Risks Work Breakdown Structure Schedule for MSD I

Project Description

Team 12026 is currently researching and developing a module for transcutaneous (through the skin) power transmission. Our project involves the transmission of power through a gap using passive magnetic coupling. This unit has potential as a medical device, and is intended as a proof-of-concept for future application in ventricular assist devices (VAD).

Customer NeedsCustomer

Need #Importance Description Comments/Status

CN1 9Transmit power

wirelessly

"Functional prototype paired motor and generator set with passive magnetic coupling." "Delivered system must be “sized” to be able to yield 100 watts at the motor (receiver)."

CN2 9Lasts long and is

reliable"Estimated design life of 99% reliability at 10+ years with 95% confidence."

CN3 9 Safely implantable Bio-compatible and low heat generation

CN4 3 Light "System weight less than 1 pound."

CN5 3 Small"Inner and outer components of the system must each be the size of a hockey puck or smaller."

CN6 3 Contained Shell containing device to prevent unwanted mass or energy transfer

CN7 3 Comfortable Minimize compressive pressure on tissue

Importance: Sample scale (9=must have, 3=nice to have, 1=preference only).

Engineering Specifications

Spec. # Importance Source Function Specification

(metric)Unit of

MeasureIdeal Value

Comments/Status

S1 9 CN1 Output Power Power W 100  

S2 9 CN1 Voltage Output Voltage V 12~15  

S3 9 CN2 Reliable % reliability % 99  

S4 9 CN2 Design Life Time Years 1095%

confident

S5 9 CN3Minimal Heat Generation Heat generation mW/cm² <40  

S6 3 CN4 Lightweight Mass kg <0.45  

S7 3 CN5 Small Diameter cm <7.6  

S8 3 CN5 Thin Thickness cm <2.54  

S9 3 CN7Contact

PressureAxial pressure on skin Pa TBD  

S10 3 CN6 Sealed Leakage rate mL/day 0  

S11 3 CN6Electrically Insulated Leakage current A 0  

Importance: Sample scale (9=must have, 3=nice to have, 1=preference only).

House of QualityEngineering Metrics

Customer Requirements

Customer WeightOutput Power

Voltage Output

Reliable

Design Life

Minimize Heat Genera

tions

Lightweight

Small ThinContact Pressur

eSealed

Electrically

Insulated

Transmit Power Wirelessly 9 9 9     3            

Lasts long and is reliable 9 3   9 9 3         3 3

Safely Implantable 9     3 3 9   3 3   3 3

Light 3           9 3 3      

Small 3           3 9 9      

Contained 3                   9 9

Comfortable 3                 9    

Target Values100W Power Output

12-15V Output

99% Reliable for 10 years

Last 10 years 95%

confident

heat loss <40

mW/cm^2

Mass <0.45kg

<7.6cm Diamet

er

<2.54 cm

thick

Axial Pressure TBD

Pa

leak 0mL/da

y

leaked 0 A/day

RawScore108 81 108 108 135 36 63 63 27 81 81

Relative Weight 12% 9% 12% 12% 15% 4% 7% 7% 3% 9% 9%

Rank 2 5 2 2 1 10 8 8 11 5 5

Functional Decomposition

Basic Calculations and Simulations

Basic Calculations and Simulations (continued)

Basic Calculations and Simulations (continued)

𝐹=𝜋𝜇4𝑀 2𝑅4[ 1𝑥2 + 1

(𝑥+2 𝑡 )2−

2

(𝑥+𝑡 )2 ]

Concept Selection

Concept A: Perpendicular Passive Magnets

Concept B: V-Oriented Passive Magnets

Concept C: Parallel-Slanted Passive Magnets

Concept D: Electromagnet StepperConcept B

Concept A

Concept Selection

Concept CConcept D

Concept SelectionSelection Criteria

Concept A (Baseline)

Concept B Concept C Concept D

Material Cost 0 0 0 -Build Time 0 - - -Ease of Fabrication 0 - - -Testing Variability 0 0 0 -Maintenance and Calibration

0 0 0 -

Controllability 0 0 0 +Expected Output 0 + + +Total Score 0 -1 -1 -3Rank 1 2 2 4Concept A: Perpendicular Passive Magnets

Concept B: V-Oriented Passive Magnets

Concept C: Parallel-Slanted Passive Magnets Concept D: Electromagnet Stepper

Current Technology

Motor/Generator Selection

 Nomenclatur

eSpeed (RPM)

Price ($)

Thickness (mm)

Diameter (mm)

Volume (mm^3) AC/DC

No. Phases

Max Power

(W)

Power Density

(MW/m^2)Brush-

lessEfficiency

(%)Mass

(g) Comments

Spec - - - 19.05 68.58 7.0E+04 - - 100 1.42 - >96% 453  

Maxon

EC 45 Flat 10,000 135 26.55 45 4.2E+04 DC 3 70 1.66 yes 83.2~85.4 141  

EC 22 60,000 223 62.7 22 2.4E+04 DC 2 100 4.20 yes 89.7~90.3 128$30 for Hall

Effect sensor

EC Max 40 12,000 430 88 40 1.1E+05 DC 2 120 1.09 yes 81.7~84.6 655  

Faulhaber

Series 3257 … CR 5,900 - 57 32 4.6E+04 DC - 84.5 1.84 no 83 242  

Series 3272 … CR 5,500 - 72 32 5.8E+04 DC - 167 2.88 no 88 312  

PMW GPM12 3,000 - 85 152 1.5E+06 DC - 110 0.07 no - -  

ebmpapst

VD-3-49.15 B00 4,500   52 63 1.6E+05 DC 3 110 0.68 yes - 590 See Link 1

VD-3-54.14 B02 6,200 - 43.3 68.4 1.6E+05 DC 3 97 0.61 yes - 520 See Link 2

VDC-3-49.15 D00 4,000 - 52 63 1.6E+05 DC 3 105 0.65 yes - 590 See Link 3

Portescap 32BF 3C K .03 12,800 - 11.2 32 9.0E+03 DC 3 10 - yes - 26 See Link 4

Applimotion UTH Series 10000 924 13.716 63.5 4.3E+04 AC 3 100 2.30 Yes   136  

Notes Design EnvelopeSpec diameter is 90% of envelope diameter Thickness

(mm) Diameter (mm)Volume (mm^3) Area (m^2) Total Heat Generation (W) Mass (g)Spec thickness is 75% of envelope thickness

Spec efficiency comes from 40mW/cm^2 heat generation (6W total loss) 25.4 76 1.2E+05 0.0152 6.08 453Spec mass comes from 80% total system weight            Link 1 http://www.ebmpapst.com/en/products/motors/vd-motors/VD_motors_detail.php?pID=150748Link 2 http://www.ebmpapst.com/en/products/motors/vd-motors/VD_motors_detail.php?pID=142157Link 3 http://www.ebmpapst.com/en/products/motors/vdc-motors/VDC_motors_detail.php?pID=142217Link 4 http://www.portescap.com/brushless-slotless-dc/product-72-nuvoDisc32BF.html

Motor/Generator Selection

    Maxon Faulhaber PMW ebmpapst Portescap Applimotion

CriteriaIdeal

Motor*

EC 45 Flat

EC 22

EC Max 40

Series 3257 CR

Series 3273 CR

GPM 12

VD-3-49.15 B00

VD-3-54.14 B02

VD-3-49.15 D00

32BF 3C K.03 UTH Series

Efficiency x - - - - - x x x x x x

Max Power x - - + - + + + - - - -Volume x + + - + 0 - - - - - +Mass x + + - 0 -   - - - + +Cost x + + - x x x x x x x -

Sum +'s x 3 3 1 1 1 1 1 0 0 1 2Sum 0's x 0 0 0 1 1 0 0 0 0 0 0Sum -'s x 2 2 4 2 2 1 2 3 3 2 2Sum x's x 0 0 0 1   2 2 2 2 2 1

Net Score x 1 1 -3 -1 -1 0 -1 -3 -3 -1 0

Uncertainty x 0 0 0 1 0 2 2 2 2 2 1Rank x 1 1 9 5 5 3 5 9 9 5 3

                         *Efficiency 96%  *Max Power 105W  *Volume 58000 mm^3  *Mass 0.25 kg  *Cost $250  

Review of Risks

ID Risk Item Effect Cause

Likelihood

Severity

Importance

Action to Minimize Risk Owner

 

Describe the risk briefly

What is the effect on any or all of the project deliverables if the cause actually happens?

What are the possible cause(s) of this risk?

    L*S What action(s) will you take (and by when) to prevent, reduce the impact of, or transfer the risk of this occurring?

Who is responsible for following through on mitigation?

1High Heat Generation Not meeting specifications,

Low generator efficiency, improper heat dissipation, 3 3 9

Research into generators, dissipating heat properly DP

2High Operating RPM failure Unsafe testing condition Power requirements 2 3 6

Extra layer of safety during testing, gearing DP

3Breakdown Torque/Slippage Lose transmission of power

Large air gap, weak magnet strength, 2 3 6

Ramp-up algorithm, fail-safe mechanism WC

4Low Power Transmission

Not meeting power transmission requirement

Heat specification causing a bottleneck 3 2 6

Research into generators, proper heat dissipation MC

5Low Motor Efficiency

Possible too much heat generation, not meeting other specifications

Lack of research into motors, 2 2 4 Do research regarding motor, NG

6 Large device Not meeting specification,

Trying to meet specification, not enough research 2 2 4

Research components, negotiate with customer, PS

7Failure of parts due to Transience Higher stress Going from 0 to x RPM, 1 1 2

Ramp-up algorithm, factor of safety NA

Likelihood scale Severity scale1 - This cause is unlikely to happen 1 - The impact on the project is very minor. We will still meet deliverables on time and within budget, but it will cause extra work2 - This cause could conceivably happen 2 - The impact on the project is noticeable. We will deliver reduced functionality, go over budget, or fail to meet some of our

Engineering Specifications.3 - This cause is very likely to happen 3 - The impact on the project is severe. We will not be able to deliver, or what we deliver will not meet the customer's needs.

Interface with 12022 

Sub-assembliesResponsibilities

Design Team Test Team

Power Supply Will have an external and internal power supplies

 

 Motor/Generator Assembly

 

Will have a thermistor circuit in the motor/generator assembly to measure

heat

Will collect the data from the thermistor using the respective

software 

Torque Measurement   Will take responsibility

 RPM Measurement

Will have a slit in the casing for accessing the motor for measurement

Will use an optical sensor to measure the RPM of the motor

 Contact Pressure on Skin

  Will measure the pressure by using a type of pressure film or force

gauge

 Rectifier circuit (if needed)

Will provide access points  

Will measure the current, voltage of desired components on the circuit.

 

 Loads for Measurement

  Will provide a range of loads for the product to see the functioning of the

total product

Work Breakdown Structure

Work Breakdown Structure (continued)

Schedule for MSD I