Linear Motor Salient Pole Position Detection Using Magnetic Field Sensors
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Solution Overview
Problem
Existing linear motors face challenges in accurately detecting the relative positions of salient poles with respect to the armature, which affects the generation of a traveling magnetic field and subsequent thrust, leading to inefficiencies in relative motion.
Innovation Solution
Incorporating magnetic-field sensors that detect the magnetic field generated by permanent magnets and passing through salient poles, allowing for precise detection of the relative positions of salient poles, thereby optimizing the traveling magnetic field and thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic-field sensors are incorporated to detect the magnetic field generated by permanent magnets, then measurement precision of salient pole positions is improved, but device complexity increases
Solution Approach 1:
The patent uses the magnetic field generated by permanent magnets as an intermediary to detect the position of salient poles. Magnetic-field sensors detect the magnetic field distribution, which serves as a mediator between the physical position of salient poles and the detection system, enabling precise position measurement without direct mechanical contact or complex sensing mechanisms.
Solution Approach 2:
The patent replaces mechanical position detection methods with magnetic field-based detection. Instead of using mechanical encoders or direct physical contact sensors, the system uses magnetic-field sensors to detect the magnetic field generated by permanent magnets, substituting a mechanical detection system with a field-based detection system that achieves higher precision with simpler mechanics.
2Productivity
If magnetic-field sensors are used to detect magnetic field passing through salient poles, then productivity of relative motion is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where magnetic-field sensors continuously detect the magnetic field generated by permanent magnets, providing real-time position information of salient poles. This feedback enables dynamic adjustment and optimization of the traveling magnetic field generation, improving the efficiency of relative motion while the system self-corrects for manufacturing variations through continuous monitoring.
Solution Approach 2:
The patent utilizes changes in magnetic field parameters (strength, distribution, direction) as permanent magnets and salient poles move relative to each other. By detecting these parameter changes, the system can precisely determine position without requiring extremely tight manufacturing tolerances, as the dynamic field parameters provide continuous position information that compensates for static manufacturing variations.
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 enhances the sensitivity and accuracy of detecting salient pole positions, leading to improved thrust generation and relative motion efficiency in linear motors, simplifying the detection process and maintaining structural integrity.
Implementation Method 1
a magnetic-field sensor that detects a magnetic field which is generated by the plurality of permanent magnets and which passes through the plurality of salient poles
Implementation Method 2
The armature causes the armature core, the armature windings, and the permanent magnets to cooperate with one another, so as to generate a travelling magnetic field. When the travelling magnetic field acts on the salient poles of the stator, the foregoing relative motion occurs.
Data Source
AI summary
A linear motor includes a stator and an armature that faces the stator with a gap therebetween. The stator has an elongated shape extending so as to cross a direction in which the stator faces the armature, and includes a plurality of salient poles that are arranged along a longitudinal direction of the stator and protrude toward the armature. The armature includes an armature core including a tooth that protrudes toward the stator, an armature winding wound around the tooth, a plurality of permanent magnets disposed on an end side of the tooth so as to be arranged along the longitudinal direction of the stator, and a magnetic-field sensor that detects a magnetic field which is generated by the plurality of permanent magnets and which passes through the plurality of salient poles.