Bus Bar Module With Narrow Section For Current Sensing
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Solution Overview
Problem
Conventional current sensors without magnetic cores in electrically-driven vehicles face sensitivity issues due to the interference of magnetic fields from adjacent bus bars, which affects the signal-to-noise ratio (SNR) of current measurement.
Innovation Solution
The bus bar module design includes bus bars with varying sectional areas and strategically placed magnetoelectric transducers to minimize the influence of adjacent bus bars' magnetic fields, enhancing the SNR by positioning transducers to detect higher magnetic flux densities relative to the current-carrying bus bars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetoelectric transducer is placed close to a bus bar to increase sensitivity, then current measurement sensitivity is improved, but magnetic field interference from adjacent bus bars increases
Solution Approach 1:
The bus bar is designed with a localized narrow section at the measurement position, creating a non-uniform current density distribution. This local structural change concentrates the magnetic flux at the measurement point, enhancing sensitivity without requiring the transducer to be placed closer to the bus bar, thereby avoiding increased interference from adjacent bus bars.
Solution Approach 2:
The sectional area of the bus bar is changed at the measurement position to create a narrow section. This parameter change (reducing cross-sectional area) increases current density and magnetic flux concentration locally, improving the signal strength for the magnetoelectric transducer while maintaining adequate spacing from adjacent bus bars to minimize interference.
2Measurement precision
If a magnetic core is added to the current sensor to improve sensitivity, then magnetic flux gathering capability is improved, but device complexity and size increase
Solution Approach 1:
Instead of using a magnetic core to gather magnetic flux, the invention utilizes the bus bar's own narrow section to concentrate and guide the magnetic flux naturally. The bus bar structure itself serves the dual function of current conduction and flux concentration, eliminating the need for separate magnetic core components and simplifying the overall sensor structure.
Solution Approach 2:
The bus bar is designed to serve multiple functions: it conducts current and simultaneously acts as a flux concentrator through its narrow section. This self-service approach eliminates the need for additional magnetic core components, reducing device complexity while maintaining sensitivity.
3Measurement precision
If the sectional area of the bus bar is reduced to increase current density, then magnetic flux density is improved, but current carrying capacity decreases
Solution Approach 1:
The bus bar is segmented into different sections along its length: narrow sections at measurement positions for high current density and flux concentration, and wide sections for adequate current carrying capacity. This segmentation allows the bus bar to simultaneously satisfy both measurement sensitivity requirements and power transmission requirements.
Solution Approach 2:
The bus bar cross-section is varied along its length, transitioning from a uniform dimension to a non-uniform dimension with narrow and wide sections. This dimensional variation allows optimization of magnetic flux density at measurement points while maintaining overall current carrying capacity through the wider sections.
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 configuration increases the sensitivity of current measurement by reducing noise interference from adjacent bus bars, thereby improving the signal-to-noise ratio and accuracy of current detection.
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
AI summary
A bus bar module includes a first bus bar, a second bus bar, and a first magnetoelectric transducer. The second bus bar is placed in parallel to the first bus bar. The first magnetoelectric transducer is placed so as to be opposed to a side surface of the first bus bar. A sectional area of the first bus bar is smaller than a sectional area of the second bus bar in a first section. The first section is a section passing through the first magnetoelectric transducer and perpendicular to an extending direction of the first and second bus bars.