Modular Inductive Position Sensor for Multi-Axis Rotor Measurement
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Solution Overview
Problem
Magnetic bearing systems require multiple expensive position sensors for accurate rotor position measurement, which increases costs and complexity, especially when detecting temperature changes and five degrees of freedom.
Innovation Solution
A modular inductive position sensor using E-shaped ferromagnetic cores with overlapping teeth, wound coil bobbins, and a frame, connected in a bridge configuration to provide linear output voltages for rotor position measurement in x, y, and z directions, allowing for low-cost, high-accuracy position feedback without mechanical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate inductive proximity sensors are used to measure rotor position in five degrees of freedom, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple proximity sensing functions into a single integrated inductive sensor assembly. The sensor uses multiple coils arranged in specific configurations (radial and axial coils) that can simultaneously measure multiple degrees of freedom (radial position, axial position, and rotational angle) without requiring separate sensor packages for each measurement dimension.
Solution Approach 2:
The inductive sensor assembly is designed to perform multiple measurement functions simultaneously using a single device. The same sensor structure with its array of coils can measure radial displacement, axial displacement, and angular position, making it a universal position sensing solution that replaces multiple specialized sensors.
2Measurement precision
If bridge connection between proximity sensors is used to enable more accurate measurement, then measurement precision is improved, but device complexity and sensor quantity increase
Solution Approach 1:
The patent integrates the bridge connection functionality directly into the sensor assembly design rather than requiring separate external bridge circuits. The coils are arranged and connected in differential bridge configurations within the sensor housing, eliminating the need for additional external bridging components and reducing overall system complexity.
3Ease of operation
If complete packages including sensors and mechanical constructions are used, then ease of operation is improved, but cost increases
Solution Approach 1:
The patent provides a modular sensor assembly that can be integrated into different mechanical structures. The sensor is designed as a self-contained unit with mounting features that allow it to be installed in various configurations, providing ease of installation while avoiding the need for expensive pre-assembled complete packages.
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 provides a cost-effective, robust, and accurate position measurement system capable of handling high-speed rotations and thermal variations, suitable for magnetic bearing systems, with reduced sensor count and mechanical complexity.
Implementation Method 1
A low-cost modular inductive position sensor is configured to determine sensor information for a magnetic bearing system. A position measurement circuit includes an AC voltage source and windings of the ferromagnetic E-shaped cores, connected to bridge connections, and having output voltages that are linearly dependent of the rotor position
Implementation Method 2
A plurality of E-shaped ferromagnetic cores are arranged to define a stator core. Each E-shaped ferromagnetic core has a plurality of teeth
Data Source
AI summary
A position sensor includes a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft. Each E-shaped ferromagnetic core has a plurality of teeth, wherein adjacent E-shaped ferromagnetic cores of the arranged plurality of E-shaped ferromagnetic cores have an overlapping tooth. The position sensor further includes a frame surrounding the arranged plurality of E-shaped ferromagnetic cores, with the E-shaped ferromagnetic cores coupled to the frame.