Inductive Signal Transmission via Coupling Coil for Rotating Transponders
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Solution Overview
Problem
Inductive signal transmission between a rotating transponder circuit and a stationary interrogation circuit is affected by varying distance, leading to stray amplitude modulation and interference, especially at higher rotational speeds, and existing high-frequency solutions are hindered by water interference and energy consumption issues.
Innovation Solution
An inductive signal transmission device with a coupling coil mounted coaxially to the rotational axis, acting as an interface between the coils, maintains constant distance and reduces energy consumption by using a passive transponder that only powers up during signal reception, operating at low frequencies like 125 kHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the transponder circuit is placed on a rotating object, then the device can monitor rotating components, but the varying distance causes amplitude modulation interference
Solution Approach 1:
An intermediary coil is introduced between the transmitter coil and the transponder coil to act as a magnetic coupling interface. This intermediary coil is fixed to the rotating object and rotates with it, maintaining constant magnetic coupling with both the stationary transmitter and the transponder, thereby eliminating amplitude modulation caused by distance variations.
2Reliability
If high frequency signals are used, then rotation dependence is reduced, but water interference increases and energy consumption rises
Solution Approach 1:
The system operates at low frequency (125 kHz) rather than high frequency, changing the operating parameter to avoid water interference while maintaining reliable signal transmission through the intermediary coil mechanism that eliminates rotation-dependent amplitude modulation.
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 eliminates amplitude modulation interference and reduces energy consumption, ensuring reliable data transmission independent of rotation and manufacturing tolerances, while maintaining efficient energy usage and cost-effectiveness.
Implementation Method 1
a coupling coil, provided with at least one closed loop turn, is mounted on the structure or on the object coaxially to the axis of rotation of the object, said coupling coil acting as an inductive coupling interface between the first coil and the second coil
Data Source
AI summary
An inductive signal transmission device including a transponder circuit (1) having at least one first coil, and an interrogation circuit (3) having at least one second coil (4). The transponder circuit is placed on an object (5) capable of rotating about at least one rotational axis (9) passing through the object. The interrogation circuit is placed on a structure, which can be stationary, to which the object is connected. A coupling coil (2), provided with at least one turn describing a ring, is mounted on the structure or the object coaxially to the rotational axis of the object. This coupling coil acts as the inductive coupling interface between the first coil and the second coil such that the inductive signal transmission is independent of the rotation of the object. The transponder circuit is of the passive type and includes at least one sensor for measuring a physical parameter. The device can be used in the automobile industry by placing the transponder circuit (1) and the coupling coil (2) on the wheel of a vehicle (5) and the interrogation circuit (3) on the chassis or body of the vehicle.