Slide 1: The Rare-Earth Scarcity Challenge
The Rare-Earth Scarcity Challenge Innovative Designs for Magnetic Position Sensing
Slide 2: Rare-Earth Materials
Rare-Earth Materials Rare-Earth Elements (REEs) are a group of 17 metallic elements, including the 15 lanthanides plus yttrium and scandium A distinction is made between Light Rare-Earth Elements (LREs) and Heavy Rare-Earth Elements (HREs)
Slide 3: Magnetic Material Comparison
Magnetic Material Comparison Commonly used target magnets Ceramic / Injection Compresion SmCo Sintered Ferrite Molded Bonded NdFeB NdFeB NdFeB Br max [T] 0.2-0.4 0.3-0.8 0.3-0.8 0.9-1.1 1.1-1.4 Coercivity [kA/m] 160 400 400 3200 900 Max Temp [°C] 250 160 160 500 220 Material Cost Low Med Med Highest
Slide 4: NdFeB Temp Grades (cont.)
NdFeB Temp Grades (cont.) There are typically 4-7 temperature grades: - Standard, M, H, SH, UH, EH, AH - Higher grades are increasingly more expensive - This is due to the manufacturing – for higher temperature grades, HREs are added in increasing relative quantities
Slide 5: Design Adjustments
Design Adjustments High BR magnets that can perform at high temp are increasingly difficult to source
Slide 6: SFANANNAVAVL DED AZZAM
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Slide 7: Magnetic Position Sensor as a Point Field Sensor
Magnetic Sensor System Design Magnetic Position Sensor as a Point Field Sensor A magnetic sensor sees one thing: The component(s) of the magnetic field vector at the “point” of the Hall Place image or graphic here sensor(s)
Slide 8: Magnetic Sensor System Design Variables
Magnetic Sensor System Design Variables Electrical Mechanical - More sensitive sensor component - Smaller air gap - Change sensor filter - Move sensor to area of higher flux density - Find a sensor sensitive to an axis with higher flux density Magnetic - Increase magnet size - Change magnetization o
Slide 9: More sensitive sensor component
Electrical More sensitive sensor 100000 BW MA732 BW MA600 component 10000 E.g. MA702 to MA600A F cutoff (Hz) 1000 Tradeoff: Cost 100 10 9 10 11 12 13 14 15 Resolution (bit)
Slide 10: Change sensor filter window
Electrical Change sensor filter Tradeoff: Dynamic Bandwidth window
Slide 11: Change sensing axis
Electrical Change sensing axis
Slide 12: Reduce the air gap
Mechanical Reduce the air gap Tradeoff: Mechanical Tolerance Stack-up
Slide 13: Shift sensor to area of higher flux density
Mechanical Shift sensor to area of higher flux density
Slide 14: Increase magnet size
Magnetic Increase magnet size Neodymium 2.5 mm D x 1 mm H magnet https://tinyurl.com/2yo3z8hx Ferrite 5 mm D x 2.5 mm H magnet https://tinyurl.com/2yo3z8hx
Slide 15: Change magnetization orientation
Magnetic Change magnetization orientation Diametral magnetization Biaxial magnetization
Slide 16: Change number of poles
Magnetic Change number of poles Tradeoff: Absolute Angle Detection
Slide 17: Tradeoff Review
Tradeoff Review Field Strength Dynamic Bandwidth Resolution Magnet Remnance Magnet Size Air Gap
Slide 18: Summary
Summary Electrical Mechanical - More sensitive sensor component - Smaller air gap - MA600A - Move sensor to area of higher flux density - Change sensor filter - Utilize MPS Sensor simulation software - MA600A, MA732, MA330 - Find a sensor sensitive to an axis with higher flux Magnetic density - Incr
Slide 19: Questions
mrS Questions
Slide 20: Thank You!
mrS Thank You!