Multi-Clock Signal Sampling for Mixed-Frequency Measurements

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Solution Overview

Problem

Existing measuring arrangements for electrical signals in power supply networks face challenges in accurately tracking sampling clocks across signals with different frequencies, leading to measurement errors and potential device malfunctions due to galvanic isolation of measuring points.

Innovation Solution

The measuring arrangement divides measurement inputs into tracking groups based on signal frequency, with each group having its own sampling clock adaptation, allowing simultaneous sampling of signals with different frequencies and reducing the need for separate clock tracking for each input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single centralized clock tracking is used for all measuring inputs, then device complexity is reduced, but measurement precision deteriorates when signals have different frequencies due to galvanic isolation

Engineering Contradiction:
Improveclock tracking structureVSAvoidsampling accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the measuring inputs into multiple tracking groups based on signal frequency characteristics. Each tracking group has its own dedicated clock tracking device that independently adjusts the sampling clock for signals within that group. This segmentation allows accurate tracking of multiple frequency sources simultaneously while avoiding the measurement errors that would occur with a single centralized tracker trying to handle divergent frequencies.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If separate clock tracking is implemented for each measuring input, then measurement precision is maintained for signals with different frequencies, but device complexity increases

Engineering Contradiction:
Improvesampling accuracyVSAvoidclock tracking structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple measuring inputs that share the same frequency characteristics into single tracking groups. By merging inputs with matching frequencies, the system reduces the total number of clock tracking devices needed compared to having separate tracking for each input, while still maintaining measurement precision for signals with different frequencies.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If signals are sampled with a fixed sampling clock, then device complexity is minimized, but measurement precision deteriorates when signal frequency varies due to galvanic isolation

Engineering Contradiction:
Improveclock adjustment mechanismVSAvoidsampling accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic clock adjustment within each tracking group by using clock tracking devices that continuously monitor the frequency of signals and adaptively adjust the sampling clock frequency accordingly. This dynamic adaptation ensures that the sampling rate remains synchronized with the signal frequency even when frequencies vary due to galvanic isolation, thereby maintaining measurement precision without requiring overly complex fixed-frequency systems.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3527996B1Measuring system and method for measuring electrical signals
Publication Date: 2023.03.29 SIEMENS AG
  • EP3527996B1 patent drawingFigure 1~2
  • EP3527996B1 patent drawingFigure 3
  • EP3527996B1 patent drawingFigure 4

AI summary

The invention relates to a measuring arrangement (21) with at least two measuring inputs (22a-c) for acquiring signals of alternating electrical quantities, a scanning device (23) downstream of the measuring inputs (22a-c) with which the signals are sampled to form digital sample values, and a clock tracking device (24) which adjusts a sampling clock used by the scanning device (23) for sampling with respect to the frequency of the signal to be sampled. In order to be able to reliably acquire signals of alternating electrical quantities even if they have different frequencies, it is proposed that the scanning device (23) be configured to sample at least two of the signals with their own separate sampling clock, wherein the clock tracking device (24) is configured to simultaneously adjust the sampling clock with respect to the frequency of the signal to be sampled for each of these at least two signals.The invention also relates to a corresponding method for measuring electrical signals.