Current Sensor Bus Bar Stray Magnetic Field Rejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current measurement systems with high-current sensors are bulky, costly, and prone to interference from adjacent electrical conductors due to the use of large magnetic cores and step-down transformers, which increase size, weight, and cost, and also suffer from magnetic field interference.
Innovation Solution
An electrical bus bar system with elongate bus bars spaced perpendicular to each other, featuring a current sensor mount portion with a circular bore to securely position current sensors, minimizing interference by aligning the sensors' sense axis perpendicular to stray magnetic fields generated by adjacent conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large magnetic cores and step-down transformers are used for high-current sensing, then measurement capability is improved, but device size and weight increase
Solution Approach 1:
The patent extracts and eliminates the heavy magnetic core and step-down transformer from the sensing system. Instead, it uses a lightweight magnetic field sensor that directly detects the magnetic field generated by current flow in the bus bar, achieving accurate measurement without the bulky components that previously were necessary for high-current sensing
Solution Approach 2:
The patent replaces the mechanical/electromagnetic transformation system (magnetic core + transformer) with a direct magnetic field detection system using a magnetic field sensor. This substitution eliminates the need for physical coupling through magnetic cores and allows direct electronic measurement of current through magnetic field detection
2Area of stationary object
If adjacent bus bars are placed close together for space efficiency, then system compactness is improved, but magnetic field interference increases
Solution Approach 1:
The patent applies local quality by orienting the magnetic field sensor's sensitive axis perpendicular to the direction of stray magnetic fields from adjacent bus bars. This directional sensitivity configuration allows the sensor to selectively detect the magnetic field from its own bus bar while rejecting interference from neighboring conductors, enabling close spacing without interference
Solution Approach 2:
The patent converts the potentially harmful stray magnetic fields from adjacent bus bars into a beneficial filtering mechanism. By aligning the sensor's sense axis perpendicular to the interference fields, the system naturally rejects the harmful magnetic coupling between adjacent conductors, allowing denser packing of bus bars while maintaining measurement accuracy
3Measurement precision
If traditional high-current sensing methods are used, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the complex magnetic core assembly and step-down transformer from the sensing system. The simplified design uses only a magnetic field sensor mounted directly on or near the bus bar, eliminating multiple components and their associated mounting, wiring, and calibration requirements
Solution Approach 2:
The bus bar structure itself serves multiple functions: it acts as both the current-carrying conductor and the mounting platform for the sensor. The sensor mounting portion of the bus bar integrates the sensor attachment features directly into the conductor structure, eliminating the need for separate sensor housings and mounting 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
This configuration reduces the sensitivity of current sensors to stray magnetic fields, allowing accurate current measurement with reduced interference and maintaining a compact, cost-effective system design.
Implementation Method 1
Measuring large currents can be done by measuring the magnetic field surrounding a conductor
Implementation Method 2
A step-down transformer may be used to attenuate the large signal that high-currents produce. These step-down transformers may also be used to generate an opposing magnetic field
Data Source
AI summary
An electrical bus bar system (10) is provided for mounting a plurality of current sensor devices (12) in close proximity to each other, each of the current sensor devices (12) having a sense axis (14). The system includes a plurality of elongate bus bars (16) extending along longitudinal axes (18) parallel to each other. The bus bars (16) are spaced from each other along a transverse axis (20) that extends perpendicular to the longitudinal axes (18). Each bus bar has a current sensor mount portion (22) configured to mount one of the current sensor devices (12) with the sense axis (14) extending parallel to the transverse axis (20).