Triaxial Magnetic Sensor Current Measurement with Noise Removal and Sign Restoration
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Solution Overview
Problem
Current measurement devices using magnetic sensors face challenges in accurately measuring current direction due to noise removal processes, which can lead to erroneous values, especially when dealing with direct and alternating currents in non-contact measurements.
Innovation Solution
A current measurement device employing a plurality of triaxial magnetic sensors with a noise remover, sign adder, and current calculator to remove noise, restore sign information, and calculate current flow, allowing for accurate non-contact measurement of direct and alternating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise removal processing (averaging or square root of sum of squares) is performed on magnetic sensor detection results, then measurement accuracy is improved, but direction information is lost leading to erroneous measurements
Solution Approach 1:
The patent segments the processing into two distinct stages: first applying noise removal processing to improve measurement accuracy, then separately restoring direction information by detecting the sign of the magnetic field at specific time points. This segmentation allows both noise reduction and direction preservation to achieve their respective goals without interfering with each other.
Solution Approach 2:
The patent performs preliminary noise removal processing on the magnetic sensor detection results before final current calculation. By removing noise components first through averaging or square root of sum of squares processing, the measurement accuracy is improved while the system prepares for subsequent direction information restoration.
Solution Approach 3:
The patent uses feedback by detecting the sign of the magnetic field at specific time points and using this information to restore the direction of the current. The system continuously monitors the magnetic field sign and adjusts the current measurement accordingly, ensuring that direction information is preserved despite noise removal processing.
2Reliability
If multiple triaxial magnetic sensors are used to preserve direction information, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple triaxial magnetic sensors into a unified processing system. By combining the detection results from multiple sensors and applying noise removal processing followed by direction restoration, the system achieves reliable current measurement while managing complexity through integrated signal processing.
Solution Approach 2:
The patent creates a universal measurement system that can handle both direct current and alternating current measurements using the same triaxial magnetic sensor configuration and processing methodology. The system is designed to be multi-functional, accommodating different current types and measurement scenarios without requiring separate dedicated systems.
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
Enables precise measurement of current flow through conductors regardless of current type, improving measurement accuracy and flexibility in installation and direction, particularly suitable for compact spaces like hybrid and electric vehicles.
Implementation Method 1
detecting a voltage induced by a magnetic field generated due to an AC current flowing through the measurement target conductor
Implementation Method 2
detecting a voltage induced by a magnetic field generated due to an AC current flowing through the measurement target conductor interlinking with a Rogowski coil
Data Source
AI summary
A current measurement device (1 and 2) is for measuring a current (I) flowing through measurement target conductors (MC1 and MC2), and the current measurement device includes: a plurality of triaxial magnetic sensors (11, 12, and 13) disposed so that a magnetic sensing direction and a relative position have a prescribed relationship; a noise remover (25a) configured to remove noise components included in detection results of the plurality of triaxial magnetic sensors; a sign adder (25b) configured to add a sign to the detection results from which the noise components have been removed, based on sign information of each of the detection results of the plurality of triaxial magnetic sensors obtained at a specific point in time; and a current calculator (25c and 25d) configured to calculate a current flowing through the measurement target conductors by using the detection results to which the sign has been added by the sign adder.