Bus Bar Module Notch Positioning for Magnetoelectric Sensor Accuracy
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Solution Overview
Problem
Conventional current sensors without magnetic cores suffer from insufficient sensitivity, and existing techniques to enhance sensitivity, such as those described in WO2013/005459 and JP 2001-74783 A, face challenges in accurately positioning magnetoelectric transducers relative to bus bars, leading to decreased accuracy in current measurement.
Innovation Solution
A bus bar module configuration that includes notches or bending portions in the bus bars to secure accurate relative positions of magnetoelectric transducers, reducing the sectional area of the bus bars and increasing current density, thereby enhancing the signal-to-noise ratio by minimizing the influence of adjacent bus bars' magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a current sensor without a magnetic core is used, then the device complexity is reduced and compactness is improved, but the sensitivity of the magnetoelectric transducer becomes insufficient
Solution Approach 1:
The patent changes the geometric parameters of the bus bar by introducing folding portions with specific curvature radii (R1, R2) and positioning dimensions (a, b, c, d). These parameter modifications concentrate the magnetic flux in the measurement region, thereby increasing the sensitivity of the magnetoelectric transducer even without a magnetic core.
Solution Approach 2:
The patent introduces folding portions that create three-dimensional spatial arrangement of the bus bar. By bending the bus bar in specific patterns with multiple curvature centers, the magnetic flux distribution is optimized in the spatial dimension, allowing the magnetoelectric transducer to detect stronger magnetic signals without requiring additional magnetic core components.
2Measurement precision
If magnetoelectric transducers are placed in folding portions of parallel bus bars, then the sensitivity is improved, but the magnetic field from adjacent bus bars interferes with the measurement
Solution Approach 1:
The patent employs asymmetric folding patterns where adjacent bus bars have folding portions at different positions along the extending direction. This asymmetric arrangement ensures that the magnetic flux from adjacent bus bars does not symmetrically overlap with the measurement region, thereby reducing magnetic interference while maintaining sensitivity.
Solution Approach 2:
The patent creates different local geometric configurations for different sections of the bus bar system. Each bus bar has folding portions with specific curvature radii and positioning that are optimized for its particular measurement location, while the overall arrangement ensures that adjacent regions have complementary patterns that minimize mutual interference.
3Object-affected harmful factors
If the positions of magnetoelectric transducers are different in the extending direction of bus bars, then the interference from adjacent bus bars is reduced, but the accuracy of current measurement decreases
Solution Approach 1:
The patent pre-calculates and pre-designs the optimal positioning of folding portions and magnetoelectric transducers before assembly. By establishing predetermined dimensional relationships (a, b, c, d) and curvature radii (R1, R2) during the design phase, the system ensures both interference reduction and measurement accuracy are achieved through careful preliminary geometric planning.
Solution Approach 2:
The patent creates a universal folding portion design that serves multiple functions simultaneously: it concentrates magnetic flux for sensitivity enhancement, positions the magnetoelectric transducer at the optimal measurement location, and through its specific geometric parameters, automatically reduces interference from adjacent bus bars. This multi-functional geometric feature eliminates the need for separate adjustment mechanisms.
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
The proposed bus bar module design significantly improves current measurement accuracy by accurately positioning magnetoelectric transducers and reducing noise interference from adjacent bus bars, resulting in a higher signal-to-noise ratio and increased sensitivity.
Implementation Method 1
The magnetic core gathers a magnetic flux generated around the bus bar due to a current flowing through the bus bar
Implementation Method 2
The magnetoelectric transducer detects a magnetic flux density of the magnetic flux to pass therethrough
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A bus bar module equipped with a current sensor includes a first bus bar, a second bus bar, a substrate, and a first magnetoelectric transducer. The first bus bar has a first notch. The second bus bar has a second notch and is placed in parallel to the first bus bar. The second notch is provided at a position different from the first notch in an extending direction of the first bus bar. The substrate is fitted to both the first notch and the second notch. Further, the substrate is sandwiched between those side surfaces of the first bus bar and the second bus bar which are opposed to each other. The first magnetoelectric transducer is placed inside the first notch and fixed to the substrate.