Planar Shunt Resistor Layout for Accurate Busbar Current Sensing
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Solution Overview
Problem
Existing current measurement solutions for busbars, particularly for low-frequency currents and short circuits, are inefficient due to reliance on expensive closed-loop transducers and indirect magnetic field sensing, which can lead to delayed protection and measurement distortion.
Innovation Solution
A compact shunt resistor with a planar resistor body and conductive traces, where measurement and connection portions are strategically positioned for optimal sensitivity and connection, integrated with a current path for accurate current measurement, and enveloped in a non-conductive material to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed-loop current transducers are used for current measurement, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the measurement function from complex closed-loop transducers and implements it through a simple shunt resistor with conductive traces directly on the resistor body. This eliminates the need for additional sensing components and complex signal conditioning circuits, achieving accurate current measurement through direct voltage measurement across the shunt resistor.
Solution Approach 2:
The patent uses conductive traces printed on the resistor body that replicate the function of separate connection terminals and measurement leads. The traces are designed with specific geometric patterns to minimize inductance and provide accurate voltage measurement, effectively copying the electrical connection function in a more integrated and compact manner.
2Device complexity
If magnetic field sensing is used for indirect current measurement, then device complexity is reduced, but measurement precision deteriorates due to distortion from adjacent busbars
Solution Approach 1:
The patent converts the harmful effect of adjacent busbars creating magnetic field distortion into a beneficial direct electrical measurement. By using a shunt resistor with conductive traces that directly measure voltage drop, the measurement system becomes immune to magnetic field interference from adjacent busbars, eliminating the distortion problem entirely rather than trying to compensate for it.
3Measurement precision
If measurement portion is positioned at bottom or upper part of resistor body, then measurement sensitivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the measurement portion and connection portions into a single integrated conductive trace structure that is directly printed or formed on the resistor body. This eliminates the need for separate components and assembly steps, making the manufacturing process simpler while maintaining optimal measurement sensitivity through strategic positioning of the trace geometry.
4Ease of operation
If connection portion is separated from measurement portion, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent segments the conductive trace into distinct measurement portion and connection portion regions within a single continuous trace structure. The measurement portion is positioned at the bottom or upper part of the resistor body for optimal sensitivity, while the connection portion extends to facilitate easy connection to external circuitry. This segmentation is achieved through trace geometry design rather than separate physical components, maintaining structural simplicity.
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 both low-frequency currents and short circuits, reducing the risk of component damage and improving measurement accuracy by minimizing electromagnetic interference and optimizing surface area usage.
Implementation Method 1
two connection terminals for measuring voltage across the planar resistor body
Data Source
AI summary
The invention pertains to a shunt resistor for a current measurement apparatus of a busbar, the resistor having a planar resistor body and two connection terminals for measuring voltage across the planar resistor body, wherein each of the two connection terminals is connected to one of two conductive traces provided on opposite sides of the resistor body, and wherein each of the conductive traces includes a measurement portion and a connection portion for connecting the measurement portion to one of the connection terminals. The invention is also directed at a current measurement apparatus including said shunt resistor and a current path provided in parallel to the shunt resistor. The invention is furthermore directed at a busbar with a corresponding current measurement apparatus, wherein the shunt resistor and the current path are provided for connecting the busbar to an electronic component.