Bi-Permanent Magnet Rotor Segmentation for Torque and Cost
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Solution Overview
Problem
Conventional permanent magnet synchronous motors using rare earth magnets are costly due to their high price and weight, and existing configurations lead to demagnetization issues that reduce motor efficiency.
Innovation Solution
The use of bi-permanent magnets, combining rare earth and ferrite magnets in a multilayer configuration within the rotor, with careful positioning to minimize demagnetization by overlapping the magnetic fields, reducing the need for high-strength magnets and maintaining effective torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If rare earth magnets are used to provide strong magnetic field strength, then torque is enhanced, but cost and weight increase
Solution Approach 1:
The rotor magnet structure is segmented into multiple regions with different magnet types. Ferrite magnets are placed in non-overlapping regions while rare earth magnets are placed in overlapping regions, creating a hybrid configuration that optimizes both cost and performance
Solution Approach 2:
Different regions of the rotor are assigned different magnet materials based on local requirements. Regions experiencing demagnetization risk use ferrite magnets, while regions requiring strong magnetic fields use rare earth magnets, optimizing overall system performance
2Force
If rare earth magnets are used to provide strong magnetic field strength, then torque is enhanced, but cost increases
Solution Approach 1:
The rotor magnet structure is segmented into multiple regions with different magnet types. Ferrite magnets are placed in non-overlapping regions while rare earth magnets are placed in overlapping regions, creating a hybrid configuration that optimizes both cost and performance
Solution Approach 2:
Ferrite magnets, which are cheaper than rare earth magnets, are strategically placed in regions where they can effectively contribute to torque production without suffering from demagnetization, reducing overall material cost
3Ease of manufacture
If ferrite magnets are used to reduce cost, then demagnetization occurs due to magnetic field from rare earth magnets, but torque is reduced
Solution Approach 1:
The rotor magnet structure is segmented into multiple regions with different magnet types. Ferrite magnets are placed in non-overlapping regions while rare earth magnets are placed in overlapping regions, creating a hybrid configuration that optimizes both cost and performance
Solution Approach 2:
The design proactively prevents demagnetization by strategically positioning ferrite magnets in non-overlapping regions where they will not be exposed to demagnetizing fields from adjacent rare earth magnets, eliminating the problem before it occurs
4Force
If uniform rare earth magnets are used throughout the rotor, then strong magnetic field is achieved, but weight and cost increase
Solution Approach 1:
The rotor magnet structure is segmented into multiple regions with different magnet types. Ferrite magnets are placed in non-overlapping regions while rare earth magnets are placed in overlapping regions, creating a hybrid configuration that optimizes both cost and performance
Solution Approach 2:
Different regions of the rotor are assigned different magnet materials based on local requirements. Regions experiencing demagnetization risk use ferrite magnets, while regions requiring strong magnetic fields use rare earth magnets, optimizing overall system performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the overall cost and weight of the motor while maintaining or enhancing torque by minimizing demagnetization and optimizing magnetic field flow, resulting in a more efficient and cost-effective motor design.
Implementation Method 1
the magnet field generated by the rare earth magnets
Implementation Method 2
minimizing a reduction in the demagnetization of the ferrite magnets
Data Source
AI summary
A rotor for an interior permanent synchronous machine. A rotor core structure includes an outer cylindrical wall juxtaposed to an air gap. A plurality of arcuately-shaped cavities is formed within the rotor core structure. The plurality of arcuately-shaped cavities is substantially concentrically layered with respect to an outer cylindrical wall of the rotor core structure. Each arcuately-shaped cavity extending between first and second end sections is juxtaposed to the outer cylindrical surface wall of the rotor structure and includes an intervening center section. A plurality of permanent magnets is inserted within the plurality of arcuately-shaped cavities. Each first end section retains a respective first permanent magnet having a first magnet field strength. Each second end section retains a respective second permanent magnet having the first magnetic field strength. Each center section retains a respective third permanent magnet having a second magnet field strength less than the first magnetic field strength.