Rotary Electric Machine Sensor Shielding for Accurate Position Detection
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Solution Overview
Problem
The detection accuracy of rotation sensors in rotary electric machines is compromised due to electromagnetic interference from power lines, which can affect the signal lines and hinder precise rotational position detection.
Innovation Solution
A configuration is introduced where a blocking portion is interposed between the power line and the signal line to suppress electromagnetic interference, utilizing a stator holder with a protrusion as a fixing and blocking portion for the rotation sensor, and arranging the power line and signal line in the axial direction to minimize electromagnetic field influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the power line is placed close to the rotation sensor for compact design, then the device complexity is reduced, but electromagnetic noise interference increases compromising detection accuracy
Solution Approach 1:
A blocking portion is introduced as an intermediary element between the power line and the rotation sensor. This blocking portion shields the signal line from electromagnetic noise generated by the power line, allowing both components to be positioned close together while maintaining detection accuracy. The blocking portion acts as a mediator that enables proximity without direct interference.
2Measurement precision
If the power line and signal line are routed separately to avoid noise, then measurement precision is improved, but the device complexity and space requirements increase
Solution Approach 1:
The blocking portion is integrated with either the stator holder or the rotation sensor structure, merging the noise shielding function with existing structural components. This eliminates the need for separate shielding elements and reduces wiring complexity while maintaining the ability to suppress electromagnetic noise effectively.
3Reliability
If the blocking portion is added between power line and signal line, then electromagnetic noise interference is suppressed, but device complexity increases
Solution Approach 1:
The blocking portion serves multiple functions: it provides electromagnetic shielding between the power line and signal line, and simultaneously serves as a structural component for mounting the rotation sensor. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving reliable noise suppression.
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 effectively suppresses electromagnetic interference, allowing for accurate rotation detection by the rotation sensor and enables a more compact design by reducing the axial length of the rotary electric machine.
Implementation Method 1
A blocking portion is interposed between the power line and the signal line to suppress the electromagnetic field
Data Source
AI summary
A rotary electric machine includes a rotor including a plurality of magnetic poles, a stator including a multi-phase stator winding, a power line that supplies power to the stator winding, and a rotation sensor that detects a rotational position of the rotor. The stator and the rotor face each other on the inner side and the outer side in the radial direction. The power line and a signal line that extends from the rotation sensor are provided so as to extend in the axial direction. Blocking portions that block an electromagnetic field generated by the power line are each interposed between the power line and the signal line.