Current Shunt Sensing Element Width Optimization
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Solution Overview
Problem
Current shunts used in renewable energy systems face inaccuracies in current measurement at higher frequencies due to the skin effect, which causes non-uniform current distribution, leading to inconsistent voltage drops across the shunt, especially when using narrow sensing elements.
Innovation Solution
A current shunt design with a sensing element of increased width relative to the conductive portion, typically within 20% to 100% of the shunt's width, to enhance the coupling coefficient and improve voltage measurement accuracy across a wide range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a narrow sensing element is used, then the voltage drop measurement is simplified and the sensing element can be easily implemented, but the measurement accuracy deteriorates at higher frequencies due to non-uniform current distribution
Solution Approach 1:
The patent changes the geometric parameter of the sensing element by increasing its width from a narrow configuration to a width that is at least 50% of the shunt width. This parameter change allows the sensing element to capture the full current distribution profile including edge effects, thereby maintaining measurement accuracy at higher frequencies while remaining manufacturable.
2Device complexity
If a narrow sensing element is used, then the device complexity is reduced, but the coupling coefficient decreases at higher frequencies due to skin effect
Solution Approach 1:
The patent modifies the sensing element width parameter to be at least 50% of the shunt width, which increases the coupling coefficient by ensuring the sensing element captures the full current distribution profile including edge effects, thereby maintaining reliability at higher frequencies.
Solution Approach 2:
The patent transitions from a narrow one-dimensional sensing approach to a wider two-dimensional sensing approach that captures current distribution across the full width of the shunt, including edge regions where skin effect is most pronounced.
3Measurement precision
If the sensing element width is increased to capture edge current flow, then the measurement accuracy at high frequencies improves, but the voltage drop measurement range may be affected
Solution Approach 1:
The patent optimizes the sensing element width parameter to be at least 50% of the shunt width, which balances the ability to capture edge current flow for high-frequency accuracy while maintaining compatibility with a wide voltage measurement range through proper element dimensioning and positioning.
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 wider sensing element increases the coupling coefficient, allowing for more accurate current measurements by capturing current flow at the edges of the shunt, even at high frequencies, resulting in improved sensing performance across a broader frequency spectrum.
Implementation Method 1
The voltage drop across the current shunt is measured to determine the current flowing through the shunt
Implementation Method 2
at higher frequencies, eddy currents caused by the skin effect can result in a non-uniform distribution of the current flow across the current shunt
Implementation Method 3
eddy currents caused by the skin effect can result in a non-uniform distribution of the current flow across the current shunt
Data Source
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Figure 3
Figure 4~5
AI summary
An apparatus and method for improved current shunt sensing in an electrical system, such as a renewable energy electrical system, is disclosed. A current shunt 200 according to aspects of the present disclosure includes a conductive portion 220 that is placed in series with an electrical system. The current shunt includes a sensing element 230 that is used to measure the voltage across the conductive portion 220 of the current shunt 200. The sensing element 230 has an increased width relative to the width of the conductive portion of the shunt 200. The increased width of the sensing element 230 provides for improved current shunt sensing that results in more accurate voltage (and thus current) measurements across a wide range of frequencies.