Planar Rogowski Coil for PCB Current Sensing
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Solution Overview
Problem
Conventional current sensors, such as Rogowski coils, face challenges in accurately measuring currents in multi-phase conductor systems due to magnetic interference from adjacent conductors and are not suitable for planar arrangements on printed circuit boards.
Innovation Solution
A current sensor arrangement featuring spatially extended measuring coils with winding-free connecting sections, allowing for a modified Rogowski coil design that reduces magnetic interference and accommodates current-carrying conductors, while being compatible with printed circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional Rogowski coil is used for current measurement, then current detection capability is provided, but magnetic interference from adjacent conductors falsifies the measurement and the toroidal shape cannot accommodate planar PCB arrangements
Solution Approach 1:
The Rogowski coil is segmented into multiple measuring coils arranged in a specific geometric pattern (e.g., triangular, rectangular) on the PCB. Each measuring coil is positioned near a specific conductor, and the coils are electrically connected in series with alternating polarity to achieve vectorial subtraction of interference fields while maintaining sensitivity to the target conductor's current.
Solution Approach 2:
The magnetic interference fields from adjacent conductors, which were previously harmful, are converted into a beneficial effect through the alternating polarity connection of the measuring coils. The interference fields from unwanted conductors induce voltages that cancel each other out due to the opposite winding directions, while the target conductor's field adds constructively, thus transforming interference into a selective measurement mechanism.
2Measurement precision
If a toroidal Rogowski coil shape is used, then current measurement is enabled, but the coil cannot be arranged planarly on printed circuit boards
Solution Approach 1:
The three-dimensional toroidal coil structure is transformed into a two-dimensional planar arrangement by flattening the coil geometry and distributing the windings across multiple layers of the PCB. The measuring coils are arranged in a geometric pattern on the PCB plane, with windings extending in different directions (e.g., x-axis and y-axis) to maintain the effective area for magnetic flux coupling while achieving planar compatibility.
3Measurement precision
If multiple measuring coils are used to reduce interference, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
Multiple measuring coils are electrically merged in series with alternating polarity connections, creating a single integrated sensing element. The PCB traces connect the coils such that their individual outputs combine vectorially, achieving interference rejection and enhanced measurement capability without requiring separate processing circuits or complex signal conditioning for each coil.
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 solution effectively measures currents in multi-phase conductor systems with reduced interference, enabling precise current detection and short-circuit protection in coordination type 2 scenarios, and allows for a space-saving, planar arrangement on printed circuit boards.
Implementation Method 1
an electrical voltage being generated in the measuring coil due to the current flowing in the current-carrying conductor
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3
AI summary
The invention relates to a current sensor arrangement having a measuring inductance (103), said measuring inductance having the following characteristics: a first measuring coil (105); a second measuring coil (107); the first measuring coil (105) and the second measuring coil (107) being electrically connected in rows and having different coil properties.