Digital Current Signal Recombination for Fast Offset Correction
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Solution Overview
Problem
Current sensors using analog electronic components face accuracy issues and require long stabilization times for offset voltage correction, particularly in the context of power supply interruptions, which is problematic in aircraft electrical networks.
Innovation Solution
A digital recombination method combining low-frequency and high-frequency current signals from separate sensors, involving digital amplification, filtering, and summation/subtraction operations to eliminate parasitic offsets, allowing for faster stabilization times and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog electronic components are used for current measurement, then the measurement can be performed with traditional components, but the accuracy deteriorates and temperature stability worsens
Solution Approach 1:
The patent replaces analog electronic components with digital signal processing. The measurement system uses digital filters, digital amplifiers, and digital summation operations instead of analog circuits, thereby eliminating the accuracy and temperature stability issues inherent in analog components.
Solution Approach 2:
The patent changes the operating parameters by moving from analog domain to digital domain. The signal processing is performed in digital form with configurable filter cutoff frequencies, digital gain factors, and programmable correction algorithms, allowing precise control without the drift and instability of analog parameters.
2Measurement precision
If offset voltage correction is performed by integrating the measured signal, then the offset can be corrected, but the stabilization time increases to seconds
Solution Approach 1:
The patent replaces the analog integrator with a digital correction algorithm. Instead of using a physical integrator circuit with large time constants, the system uses digital signal processing to calculate and apply offset corrections, reducing stabilization time from seconds to milliseconds or less.
Solution Approach 2:
The patent performs offset correction in advance through digital processing. The system measures the offset, calculates the correction factor, and applies it before the final measurement is taken, thereby eliminating the need for long stabilization periods required by analog integrators.
3Adaptability or versatility
If low-frequency and high-frequency current signals are measured separately, then each frequency range can be optimized, but the recombination introduces parasitic offsets
Solution Approach 1:
The patent uses digital signal processing to combine low-frequency and high-frequency current signals. Digital amplifiers with precise gain factors and digital filters with exact cutoff frequencies are used to process each signal band, and digital summation combines them without introducing the parasitic offsets that plague analog recombination circuits.
Data Source
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AI summary
The invention relates to a method for measuring a current digitally recombining a low-frequency current signal IBF from a low-frequency current sensor and at least one high-frequency current signal IHF+offset from a high-frequency current sensor on the same current conductor, the method comprising the steps of amplifying, filtering and summing the signals, said steps being suitable for eliminating a DC offset created in the amplification of the HF signals.