Inductive Position Sensor Shield Layout Against High-Voltage Interference
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Solution Overview
Problem
Inductive position sensors face interference from high voltage sources, such as high voltage electric motors, which affect their accuracy in detecting the relative position between members due to low frequency electrostatic coupling.
Innovation Solution
The implementation of an inductive position sensor with an electrostatic shield that includes conductive traces arranged to prevent current loops, which is grounded and disposed on a printed circuit board or substrate, along with capacitors coupled between windings and ground to reduce interference, providing a low impedance path to ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrostatic shield with conductive traces is added to reduce electromagnetic interference, then the reliability of position detection is improved, but the device complexity increases
Solution Approach 1:
The electrostatic shield is segmented into multiple conductive traces arranged in a specific pattern rather than using a solid continuous shield. This segmentation approach reduces the shield's impact on magnetic field coupling while still providing effective electrostatic interference protection, thus improving position detection reliability without excessive complexity increase
Solution Approach 2:
The conductive traces are strategically positioned and configured to provide electrostatic shielding specifically in regions where interference from high voltage sources is most problematic, rather than uniformly shielding the entire sensor. This localized approach optimizes the balance between interference reduction and device complexity
2Object-affected harmful factors
If conductive traces are arranged to prevent current loops in the electrostatic shield, then electromagnetic interference is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The conductive traces are designed with an asymmetric arrangement that inherently prevents current loop formation without requiring extremely precise symmetric positioning. The asymmetric pattern breaks the continuity that would allow current loops, reducing electromagnetic interference while maintaining reasonable manufacturing tolerances
Solution Approach 2:
The trace arrangement is pre-designed and pre-configured during the manufacturing process to inherently prevent current loop formation, rather than requiring post-manufacturing adjustment or verification. This preliminary configuration ensures interference reduction is achieved without demanding excessive precision during assembly
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 reduces electromagnetic interference, enhancing the accuracy and reliability of the inductive position sensor in detecting relative positions by minimizing the impact of high voltage sources.
Implementation Method 1
at least one electrostatic shield. The electrostatic shield can include a plurality of conductive traces arranged so that no current loops are formed in the electrostatic shield
Implementation Method 2
low frequency electrostatic coupling
Implementation Method 3
a magnetic field generated by alternating current flowing through the transmit aerial induces an electromotive force in the receive aerial that generates a current that is dependent on the position of the coupling element
Data Source
AI summary
Inductive position sensors for sensing relative position (e.g., relative rotary position) between members are provided. In one example implementation, the inductive position sensor includes a transmit aerial having at least one transmit winding. The inductive position sensor can include a receive aerial having one or more receive windings. The inductive position sensor can include a coupling element operable to be disposed on the second member. The inductive position sensor can include processing circuitry configured to provide one or more signals indicative of the position of the first member relative to the second member based on current induced in the one or more receive windings resulting from an oscillating signal provided to the transmit winding. The inductive position sensor includes at least one electrostatic shield. The electrostatic shield can include a plurality of conductive traces arranged so that no current loops are formed in the electrostatic shield.