Magnetic Bearing Preliminary Design

ReviewTeam miniMuffin

Lauren Glogiewicz Jacob Beckner Kevin Bodkin James Holley

Philip Terry

Project Description• Different bearing design using magnetic fields 

• Electromagnets will levitate an axle 

• Optical sensors monitor position of axle

• FPGA interprets data to control electromagnets

• System less prone to mechanical restraints

Lauren

Why Magnetic Bearings?• Eliminates friction present in mechanical bearings

o Higher speed of rotation possibleo Fewer parts require maintenanceo Not as susceptible to heat  

                                                                             VS

Lauren

Project Objectives

Lauren

Concept: 8-Magnet Bearing

Lauren

First Objective: 1D Proof of Concept Design

Lauren

Final Objective: Magnetic Ring Bearing with Axial Bearing

 

James

Final Objective: Magnetic Ring Bearing with Axial Bearing

James

Hardware Functional Diagram

James

8-12 bits per magnet sent to

current control via FPGA I/O

Convert distance error to current

8x sensor distance in to FPGA

Software Functional Diagram

James

Design Constraints• Speed of Control

o Need a tight control loop between sensors & FPGAo Electromagnets need to be adjusted continuously

• Power

o Electromagnets are typically high powero Bearings only useful if energy efficient

• Budget

o Certain components could be expensive

James

Major Components• Optical Sensors

• FPGA: Hardware & Software Interface

• Current Control

• Electromagnets

• Power Supply

Jake

Sensing Devices• Optical sensors will track axle position

• Sensors will be paired with electromagnets

• Vital to the positioning feedback loop

Jake

Altera Flex 6000 FPGA

• 199 I/O pinso 8 magnet

control with 12-bit accuracy

• Re-programmable with Altera software

• 100 MHz maximum clock frequency

Jake

Electromagnets• Found source of low-cost, high-power magnets

• Currently testing two models:

o 1" Magnet: 3 V, 5.5 W, 25 lb holding force

o 2" magnet: 6 V, 7 W, 105 lb holding force

Kevin

Current Control• Will receive information from the FPGA

• Information fed to D/A converter to amplifier

• Amplifier will feed into BJT-based current source

• Will change the strength of the electromagnets

• Current limited based on the magnet used

Kevin

Power Supply

•  Need the following: o 15 V for OpAmps o 6 V +/- mV for magnets o 3.3 V for integrated circuits

• Initial work using power supplies & 12 V batteries 

• Final design should use wall power

Kevin

Prediction of Material CostsItem Part No. Cost Quantity Total Cost

FPGA Altera FLEX 6000 $43 2 $86.00

Electromagnets EM 200 $41.61 15 $624.15

Optical Sensors Sharp GP2Y0D805Z0F $3.70 15 $55.50

BJT TRANS NPN 10VCEO 5A $0.38 25 $9.50

Op Amps $1.00 25 $25.00

Capacitors $0.60 100 $60.00

Resistors $0.60 100 $60.00

High Power Diodes $1.71 15 $25.65

Wire Wire T Lead Plastic 22AG $18.00 5 $90.00

Nuts, Bolts, Screws Aluminum (25 pack) $9.58 3 $28.74

Aluminum 6ft x 1/4" x 2" $30.22 1 $30.22

Machining $200.00 1 $200.00

PCB $60 3 $180.00

Shipping and Handling $10.00 6 $60.00

Posters/Presentation $70 $70

Total: $1,600.76

Phil

Sources of Funding• UROP

• Boettcher Scholar Educational Enrichment Grant

• Engineering Excellence Fund Mini Grant

Phil

Division of Labor• For preliminary steps, we will divide as follows:

o Jake: Interfacing/ programming FPGA

o James: Electromagnets and supporting electronics

o Kevin: Power electronics

o Lauren: Mechanical design

o Phil: Sensors and documentation

Phil

Timeline

Phil

Risks and Contingency Plan

• Mechanical Problems

o Some parts manufactured by other people

• Time delay of sensors

o Look into components with faster responseo Different sensing types: capacitive, magnetic field, etc.

• Time delay of current control

o Better components

Phil

Questions?