Passive Telemetry System with Inductive Impedance Detection

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Solution Overview

Problem

Existing telemetry systems face challenges in reducing measurement times, simplifying conditioning electronics, and lowering power consumption, especially when using resistive transducers, which often require complex frequency sweeps and increased measurement complexity.

Innovation Solution

A telemetry system employing a passive resistive transducer with a calibration capacitor and a first coupling inductor, coupled inductively with a reading unit to detect impedance amplitude variations at a fixed frequency, allowing for wireless measurement and power transmission without wired connections, simplifying the measurement process and extending the use to resistive transduction sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If frequency sweep is performed to reconstruct impedance trend and recognize significant frequencies, then measurement accuracy is improved, but measurement time increases

Engineering Contradiction:
Improveimpedance measurement accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-defining a fixed working frequency based on the calibration capacitor value before measurement. This eliminates the need for frequency sweep during actual measurement, as the system directly measures impedance at the predetermined frequency, thus reducing measurement time while maintaining accuracy through the fixed-frequency approach.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If frequency sweep and impedance trend reconstruction are performed, then measurement accuracy is improved, but electronics complexity increases

Engineering Contradiction:
Improveimpedance measurement accuracyVSAvoidconditioning electronics complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the frequency determination function from the measurement process by using a calibration capacitor to pre-establish the working frequency. This separates the frequency setting function from the impedance measurement function, eliminating the need for complex frequency sweep control electronics and signal processing circuits, thus simplifying the overall system while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If inductive coupling is used for wireless power and data transmission, then ease of operation is improved, but power consumption increases

Engineering Contradiction:
Improvewireless operation capabilityVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic action by using AC excitation at a fixed frequency to drive the inductive coupling system. The calibration capacitor resonates at this frequency, creating periodic current flow that efficiently transfers power and data wirelessly. This periodic operation allows the system to maintain wireless functionality while managing power consumption through resonant coupling at the predetermined frequency.

Inventive Principle:
Principle #19Periodic action

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 approach reduces measurement times, simplifies electronics, and lowers power consumption while enabling wireless transmission of data, making it suitable for harsh environments and expanding the range of measurable physical or chemical quantities.

Implementation Method 1

a second coupling inductor suitable to realise an inductive coupling with said first coupling inductor

Methodology Applied
Scientific EffectInductive coupling: Electromagnetic Induction

Data Source

PatentEP3093626B1System and method for the measurement of quantities
Publication Date: 2022.10.26 UNIV DEGLI STUDI DI BRESCIA
  • EP3093626B1 patent drawingFigure 1
  • EP3093626B1 patent drawingFigure 2
  • EP3093626B1 patent drawingFigure 3~4

AI summary

This invention relates to a telemetry system for the wireless measurement of a quantity, comprising at least a passive transducer sensitive to a variation of said quantity and a reading unit coupled to said passive transducer and suitable to detect, condition and process information of a measurement coming from the passive transducer. Each passive transducer comprises a resistive transduction sensitive element, a calibration capacitor, suitable to define a working frequency of the system, and a first coupling inductor. The reading unit comprises a second coupling inductor suitable to realise an inductive coupling with said first coupling inductor, and detection means suitable to detect a variation of amplitude of the real part of the impedance of the assembly constituted by the passive transducer and the second coupling inductor, at the working frequency, said amplitude of the real part of the impedance depending on the resistance value of the sensitive element.