Inductive Position Sensor Resonant Rotor PCB Space Reduction
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Solution Overview
Problem
Conventional inductive position sensors require significant printed circuit board (PCB) space, are complex, and susceptible to electromagnetic emissions and disturbances, leading to increased costs and reduced accuracy.
Innovation Solution
The design incorporates multiple excitation and receive coils configured in a three-phase circuit with twisted loops around a stator core, minimizing electromagnetic interference and using a resonant rotor with capacitive filtering to enhance signal strength and reduce harmonics, allowing for more precise position sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inductive position sensors use single-turn receiving coils laid out in rotational symmetry around excitation coils, then the sensor can detect position changes, but the PCB space required becomes significant and device complexity increases
Solution Approach 1:
The receiving coil is divided into multiple turns (e.g., 3-10 turns) instead of using a single-turn coil. This segmentation allows the coil to achieve sufficient signal strength and detection precision while occupying less PCB space, as the multi-turn configuration concentrates the sensing capability in a more compact area.
Solution Approach 2:
The patent combines multiple functional elements into a integrated PCB-based sensor assembly where excitation coils and multi-turn receiving coils are co-located and interconnected. This merging reduces the overall PCB space required compared to distributed conventional designs, while maintaining position detection accuracy through optimized coil geometry and coupling.
2Measurement precision
If conventional inductive position sensors use multiple coils configured in rotational symmetry, then position detection capability is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The sensor design uses a universal multi-turn receiving coil configuration that can detect position changes in various orientations and applications. The same basic multi-turn coil structure serves multiple sensing functions, reducing device complexity compared to specialized single-turn coil arrangements that require different configurations for different sensing needs.
Solution Approach 2:
The patent optimizes parameters such as the number of turns (3-10 turns), coil diameter, and winding pattern to achieve accurate position detection with simpler structures. By carefully selecting these parameters, the sensor maintains measurement precision while reducing structural complexity and manufacturing difficulty.
3Device complexity
If conventional inductive position sensors use single-turn coils, then the design is simpler, but the sensor becomes susceptible to electromagnetic emissions and disturbances reducing accuracy
Solution Approach 1:
The patent uses excessive action by implementing multiple turns (3-10 turns) in the receiving coil, which provides redundant signal paths and enhanced signal strength. This excessive winding compensates for electromagnetic disturbances and emissions, improving reliability while maintaining relatively simple coil construction suitable for PCB fabrication.
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 reduces the form factor and complexity of inductive position sensors, improves accuracy by minimizing electromagnetic interference, and increases signal strength, making them more cost-effective and reliable.
Implementation Method 1
an excitation coil configured to generate an electromagnetic field when electrical current flows through the coil, a receiving coil configured to detect an electrical potential, a voltage, induced in the receiving coil by the currents flowing through the excitation coil
Implementation Method 2
The rotor is configured to disturb the amount of electrical potential induced in the receiving coil based on the rotor's position. The rotor can be defined to affect the inductive coupling between the excitation coil and the receiving coil by mathematical functions (each a transfer function)
Data Source
AI summary
A resonant rotor, for use in an inductive position sensor, includes a rotor core, a first rotor coil, and a rotor capacitor. The first rotor coil includes a first twisted rotor loop drawn about the rotor core and the rotor capacitor is connected in series with the first rotor coil. For a second embodiment, the first rotor coil includes a second twisted rotor loop. The first rotor coil has a first symmetry and the inductive position sensor includes a stator. An excitation coil is drawn on the stator and has a second symmetry. The first symmetry substantially corresponds to the second symmetry. A method for determining a position of an object using an inductive position sensor includes generating three electromagnetic fields using respective excitation coils, inducing voltages, respectively, in three receive coils, and determining based on voltages a position of an object coupled to a resonant rotor. The voltages being based on mutual inductances arising between the rotor with each of the excitation and receive coils, and the elimination, by the resonant rotor, of mutual inductances arising between the excitation and receive coils.