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?
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