Permanent Magnet Motor Angle Detection Leakage Flux Shielding
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Solution Overview
Problem
In permanent magnet motors, armature leakage magnetic flux reduces angle detection precision due to leakage magnetic flux from the rotation shaft end and armature winding, which is not effectively addressed by existing technologies.
Innovation Solution
A permanent magnet motor design incorporating a plate member made of a magnetic substance between the semiconductor sensor and the armature iron core, guiding the armature leakage magnetic flux to bypass the semiconductor sensor, thereby reducing leakage and improving detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic substance is arranged around the semiconductor sensor, then the magnetic resistance around the semiconductor sensor is decreased, but the armature leakage magnetic flux is conversely concentrated around the semiconductor sensor, resulting in a decrease in angle detection precision
Solution Approach 1:
A plate member made of magnetic substance is introduced as an intermediary component between the armature and the semiconductor sensor. This plate member serves as a magnetic flux guide that redirects the armature leakage magnetic flux away from the sensor region, effectively mediating the interaction between the armature and sensor to prevent harmful flux concentration while maintaining necessary magnetic circuit functionality
Solution Approach 2:
The magnetic flux path is segmented by introducing the plate member, which divides the magnetic flux flow into separate regions. The plate member creates distinct magnetic flux pathways that guide leakage flux away from the semiconductor sensor, segmenting the原本 continuous magnetic field into controlled regions that prevent interference with angle detection
2Device complexity
If the plate member is integrated with the frame section between the angle detector and armature iron core, then the structure is simplified, but the plate member cannot effectively guide the armature leakage magnetic flux away from the semiconductor sensor
Solution Approach 1:
The plate member is designed as a separate, independent component rather than being integrated with the frame. This segmentation allows the plate member to be positioned optimally for guiding magnetic flux away from the sensor, while maintaining structural simplicity through separate installation rather than complex integration
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 armature leakage magnetic flux, enhancing the angle detection precision by routing the magnetic flux through the magnetic substance, thus minimizing interference with the semiconductor sensor.
Implementation Method 1
A plate member of a thin plate made of a magnetic substance is provided between the semiconductor sensor and an end portion of the armature iron core on the semiconductor sensor side... The plate member includes a first section extending in the axial direction and a second section extending in an imaginary plane having a perpendicular line along the axial direction
Data Source
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AI summary
Provided is a permanent magnet motor including an armature, a rotor, and an angle detector. The angle detector includes a sensor magnet and a semiconductor sensor. The sensor magnet is magnetized into two poles and is provided in an end portion of a rotation shaft, and has the same rotation center as that of the rotation shaft. The semiconductor sensor is opposed to the sensor magnet in an extension direction of the rotation shaft. The semiconductor sensor and the sensor magnet have a gap formed therebetween, and a plate member made of a magnetic substance is provided between the semiconductor sensor and an end portion of the armature iron core on the semiconductor sensor side.