Rotating Shielding Means for Permanent Magnet Protection
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Solution Overview
Problem
Electrical machines face issues with demagnetization and torque ripple due to external magnetic fields, which are typically addressed by using large permanent magnets or complex designs to mitigate these effects.
Innovation Solution
A shielding means made of electrically conductive and magnetically non-conductive material is strategically placed on the permanent magnets to shield them from external magnetic fields, generating counter magnetic fields that reduce demagnetization and torque ripple effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large permanent magnets are used to counteract demagnetization effects, then the magnetic field strength is improved, but the device complexity and construction difficulty increase
Solution Approach 1:
A shielding means made of electrically conductive and magnetically non-conductive material is introduced as an intermediary between the permanent magnet and external magnetic fields. This shielding means generates counter magnetic fields through induced eddy currents, protecting the permanent magnet from demagnetization without requiring the permanent magnet itself to be larger or stronger.
2Stability of the object's composition
If complex designs are used to mitigate torque ripple, then the torque smoothness is improved, but the device complexity increases
Solution Approach 1:
The shielding means acts as a mediator that reduces torque ripple by generating counter magnetic fields that compensate for the harmful magnetic interactions. This approach simplifies the overall design compared to traditional methods that require complex magnet arrangements, skewing, or displacement techniques to achieve similar torque smoothing effects.
3Adaptability or versatility
If permanent magnets are exposed to high external magnetic fields, then the operational flexibility is improved, but the magnetic field strength deteriorates due to demagnetization
Solution Approach 1:
The shielding means provides preliminary protection against demagnetization by generating counter magnetic fields before the external magnetic fields can significantly affect the permanent magnet. This preemptive shielding allows the electrical machine to operate flexibly in various external magnetic field conditions without risking permanent magnet demagnetization.
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
The solution effectively reduces demagnetization and torque ripple by creating a counter magnetic field within the shielding means, minimizing the impact of external magnetic fields on the permanent magnets, thereby enhancing the stability and efficiency of the electrical machine.
Implementation Method 1
the shielding means is built of an electrically conductive and magnetically non-conductive material
Implementation Method 2
a shielding means shielding the at least one permanent magnet from interactions with external magnetic fields is adjacently disposed to the permanent magnet
Data Source
Figure 1~2
AI summary
Electrical machine (1) comprising a stator (2) and a rotor (3), whereby the rotor (3) is provided with at least one permanent magnet (9), wherein a shielding means (12) shielding the at least one permanent magnet (9) from interactions with external magnetic fields is adjacently disposed to the permanent magnet (9) on rotor (3) supporting the at least one permanent magnet (9) and able to rotate around a center axis (4).