Current Sensor with Conductive Convex Portion for Frequency-Independent Measurement
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Solution Overview
Problem
Current sensors using magnetoelectric conversion elements face challenges in maintaining measurement accuracy when the frequency of the current changes, leading to varying sensitivity and difficulty in obtaining correct measurements, especially in devices like electric vehicles where frequency changes occur during idling, acceleration, and regenerative braking.
Innovation Solution
The current sensor incorporates a conductive convex portion in the current path to align minimum and maximum frequency magnetic flux densities, allowing the magnetoelectric conversion element to be positioned where the magnetic flux density change is minimal, and uses multiple elements on the same substrate for differential processing to cancel out external magnetic field influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic sensor is disposed in the middle of the conductor to be measured, then the current sensitivity is improved for low frequency currents, but the measurement accuracy deteriorates for high frequency currents due to skin effect
Solution Approach 1:
The conductor to be measured is segmented into multiple sections along its length. Multiple magnetoelectric conversion elements are arranged at different positions corresponding to different sections. This segmentation allows each element to detect magnetic fields at specific locations, and the combined output provides accurate measurement across a wide frequency range by compensating for skin effect distribution.
Solution Approach 2:
Multiple detection signals from magnetoelectric conversion elements arranged at different positions are merged through differential processing. By combining the outputs of elements positioned at different locations along the conductor, the system achieves frequency-independent measurement accuracy, as the differential configuration cancels out the effects of skin effect and magnetic flux density variations.
2Adaptability or versatility
If the magnetic sensor is disposed away from the central position to compensate for high frequency skin effect, then the high frequency measurement is improved, but the low frequency sensitivity is reduced
Solution Approach 1:
The system dynamically adapts to different frequency conditions by utilizing multiple magnetoelectric conversion elements at different positions. The differential processing of signals from these elements creates a dynamic response that automatically compensates for frequency-dependent effects, maintaining optimal sensitivity across the entire frequency range without requiring manual adjustment.
Solution Approach 2:
The system changes the effective detection parameters by using multiple elements at different positions along the conductor. By varying the combination of element outputs through differential processing, the system adjusts its effective sensitivity profile to maintain accuracy across different frequencies, transforming the static detection configuration into a multi-parameter measurement system.
3Device complexity
If a single magnetoelectric conversion element is used, then the device complexity is reduced, but the measurement accuracy varies with frequency changes
Solution Approach 1:
The single sensor approach is segmented into multiple magnetoelectric conversion elements distributed along the conductor. This segmentation increases measurement accuracy stability across frequencies while keeping each individual element simple. The segmented configuration allows differential processing to cancel frequency-dependent errors without requiring complex individual sensor designs.
Solution Approach 2:
Multiple magnetoelectric conversion elements are arranged to serve multiple functions simultaneously: each element detects magnetic field at its specific position, and collectively they provide frequency-compensated measurement through differential processing. This multi-functional arrangement maintains relative simplicity while achieving accurate measurement across varying frequency conditions.
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 design enables accurate current measurement across varying frequencies by minimizing the difference between minimum and maximum frequency magnetic flux densities and reduces measurement error by effectively canceling out magnetic field influences, thus maintaining high accuracy and cost-effectiveness.
Implementation Method 1
a method has been well known that utilizes a magnetoelectric conversion element (magnetic detecting element) such as a magnetoresistance effect element or a Hall element, used for sensing a magnetic field generated from a current to be measured flowing through a current path
Implementation Method 2
sensing a magnetic field generated from a current to be measured flowing through a current path
Implementation Method 3
If the frequency of the current to be measured flowing through such a flat-shaped conductor to be measured 901 increases, the current to be measured is concentrated into end portions of the conductor to be measured 901 by a skin effect
Data Source
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AI summary
[Object] A purpose is to provide a current sensor capable of accurately measuring a current to be measured even if the frequency of the current to be measured changes. [Solution] A current sensor 101 includes a first current path 12 including a first flat-shaped portion 12f, and a first magnetoelectric conversion element 13 arranged on the first current path 12 and configured to detect magnetism generated when a current to be measured flows through the first current path 12, wherein the current sensor 101 measures the current to be measured of a device to which the first current path 12 is connected, a first conductive convex portion 12w is provided, in the first current path 12, in a direction in which the current to be measured flows, and the first magnetoelectric conversion element 13 is arranged at a position on the first current path 12, at which a minimum frequency magnetic flux density serving as a magnetic flux density in a case of passing the current to be measured of a minimum frequency used in the device and a maximum frequency magnetic flux density serving as a magnetic flux density in a case of passing the current to be measured of a maximum frequency used in the device substantially coincide with each other.