Spoke Type Motor Rotor Asymmetric Flux Barriers
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Solution Overview
Problem
Spoke type permanent magnet motors experience local demagnetization at the ends of permanent magnets, leading to performance degradation, and existing solutions either increase the magnet thickness or stator distance, which are costly or voluminous.
Innovation Solution
The motor design incorporates a rotor with cavities for holding permanent magnets, flux barriers, and ribs that are asymmetrical in shape and width, minimizing demagnetization without increasing the magnet thickness or stator distance by optimizing the magnetic flux path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of permanent magnets is increased to reduce demagnetization, then the force resistant to demagnetization is improved, but the volume and production cost increase
Solution Approach 1:
The patent applies local quality by creating flux barriers with different widths at different locations. The first flux barrier has a greater width than the second flux barrier, optimizing the magnetic flux path locally at each end of the permanent magnet to prevent demagnetization without increasing overall magnet thickness.
Solution Approach 2:
The patent employs asymmetry by designing unequal flux barrier widths where the first flux barrier is wider than the second flux barrier. This asymmetric configuration optimizes the magnetic flux distribution to counteract demagnetization effects at different magnet ends, achieving improved reliability without proportional volume increase.
2Reliability
If the distance between permanent magnets and stator is increased to reduce demagnetization, then the force resistant to demagnetization is improved, but the motor volume increases
Solution Approach 1:
The patent uses local quality by positioning flux barriers at specific locations adjacent to permanent magnet ends where demagnetization occurs. The varying widths of flux barriers create localized magnetic flux paths that redirect flux away from vulnerable magnet ends, improving demagnetization resistance without increasing overall motor volume.
Solution Approach 2:
The flux barriers act as intermediary structures between the permanent magnets and the magnetic flux path. By introducing these intermediate elements with optimized widths, the patent redirects magnetic flux to prevent demagnetization without requiring increased spacing between magnets and stator, thus avoiding volume increase.
3Device complexity
If conventional flux barrier design is used, then the structure is simple, but demagnetization occurs at permanent magnet ends
Solution Approach 1:
The patent improves upon conventional uniform flux barrier designs by implementing local quality variations. The first flux barrier has a greater width than the second flux barrier, creating localized optimization at different magnet ends. This non-uniform configuration enhances demagnetization resistance while maintaining reasonable structural complexity.
Solution Approach 2:
The patent applies parameter changes by varying the width parameter of flux barriers along the magnetic flux path. The first flux barrier width is changed to be greater than the second flux barrier width, optimizing magnetic flux distribution to prevent demagnetization. This parameter variation achieves improved reliability with controlled increase in device complexity.
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 design effectively reduces demagnetization and enhances the force resistance to demagnetization, improving motor performance without increasing production costs or volume.
Implementation Method 1
flux barriers configured to communicate with first ends of the cavities and formed adjacent to an outer circumferential surface of the rotor; and ribs formed between the outer circumferential surface of the rotor and the flux barriers
Data Source
AI summary
A motor that minimizes demagnetization to improve a force resistant to the demagnetization without increasing a thickness of each permanent magnet and a distance between each permanent magnet and a stator includes a rotor that rotates in one direction and includes cavities configured to hold magnets, flux barriers configured to communicate with first ends of the cavities and formed adjacent to an outer circumferential surface of the rotor, and ribs formed between the outer circumferential surface of the rotor and the flux barriers. Each of the ribs is configured such that a width of one end thereof at an upstream side in a rotational direction of the rotor is wider than that of the other thereof at a downstream side in the rotational direction.