Inductive Position Sensor with Phase-Shifted Receiver Coils
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Solution Overview
Problem
Inductive position sensors require longer receiver coils to detect linear or angular movements of conductive targets, which increases their size and reduces accuracy due to interference from magnetic fields.
Innovation Solution
The design incorporates at least two conductive targets, each covering half the detection range of the receiver coils, which are phase-shifted and spaced equally, to enhance accuracy and reduce coil length, using a processing unit to calculate the target's position based on the amplitude imbalance of induced signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the receiver coils are made longer to increase detection range, then the detection range is improved, but the accuracy deteriorates due to increased magnetic field interference
Solution Approach 1:
The invention divides the detection task into two separate receiver coils (first and second receiver coils) that are phase-shifted relative to each other. Each coil covers a portion of the detection range, and their combined output provides full-range detection. This segmentation allows each coil to be shorter while maintaining overall detection range, thereby reducing magnetic field interference and improving accuracy.
2Measurement precision
If additional magnetic shielding is added to reduce magnetic field interference, then the accuracy is improved, but the device complexity increases
Solution Approach 1:
The invention replaces mechanical magnetic shielding structures with an electrical solution using phase-shifted receiver coils. By using two coils with different phase shifts and processing their combined signals, the system achieves immunity to magnetic field interference without adding physical shielding layers, thus improving accuracy while maintaining simple device structure.
3Device complexity
If the receiver coils are made shorter to reduce size, then the device complexity is reduced, but the detection range decreases
Solution Approach 1:
The invention introduces a phase dimension to the detection system by using two receiver coils with different phase shifts. This allows the system to achieve extended detection range through phase differentiation rather than through increased physical coil length. The phase-shifted coils can be shorter while their combined phase information provides full-range detection capability.
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 increases the detection range and accuracy of the inductive position sensor by minimizing interference from magnetic fields and reducing coil length, thereby enhancing precision in detecting conductive target positions.
Implementation Method 1
the transmitter coil induces a secondary voltage in the two receiver coils, which depends on the position of the conductive, e.g., metallic, target above the receiver coils
Implementation Method 2
utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target
Data Source
AI summary
An inductive position sensor for detecting a linear or angular movement of a conductive target, including: a transmitter coil; a first receiver coil and a second receiver coil, where the first receiver coil and the second receiver coil have a linear or angular shape and define the detection range of the inductive linear or arc position sensor; a first conductive target and a second conductive target; the first conductive target and the second conductive target each have a linear or angular shape extension of half the detection range of the inductive position sensor and are spaced from each other by half the detection range of the inductive position sensor.