Active Linear Current Transducer PCB Rogowski Coil
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Solution Overview
Problem
Existing methods for measuring alternating currents face challenges such as high precision errors due to parasite inductances, core saturation, limited frequency response, high costs, and susceptibility to interference and temperature drift, particularly in measuring high currents and low frequencies.
Innovation Solution
An active linear current transducer based on Rogowski coils integrated with electronics on a printed circuit board for signal amplification, filtering, and quality parameter measurement, featuring a multi-layer design with high permeability materials to enhance sensitivity and adaptability, allowing non-invasive measurement across a wide current range without electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Rogowski coil with air core is used to measure alternating current without electrical contact, then measurement safety and isolation are improved, but manufacturing precision requirements increase and production cost rises
Solution Approach 1:
The patent replaces the traditional mechanical hand-winding process with an automated PCB-based coil structure. The coil is formed by etching conductive traces on a printed circuit board, eliminating the need for manual winding operations. This substitution of mechanical fabrication with a standardized manufacturing process significantly reduces precision requirements while maintaining measurement accuracy and safety.
2Measurement precision
If the Rogowski coil output signal is integrated using an external device, then current measurement capability is improved, but signal loss and interference increase
Solution Approach 1:
The patent integrates the signal conditioning electronics directly into the PCB structure housing the Rogowski coil. The amplifier and integrator circuits are mounted on the same board as the coil, creating a compact unified device. This merging eliminates long external signal paths that would otherwise be susceptible to interference and signal loss, while maintaining full measurement capability.
3Measurement precision
If a current transformer with closed core is used to measure high currents, then measurement precision is improved, but installation complexity increases due to circuit opening requirements
Solution Approach 1:
The patent divides the measurement system into two independent parts: the Rogowski coil that remains outside the circuit and the current-carrying conductor that stays intact. Unlike closed-core transformers that require circuit opening, the Rogowski coil can be installed around an existing conductor without disrupting the electrical circuit, greatly simplifying installation while maintaining measurement precision.
4Adaptability or versatility
If Hall effect sensors are used to measure very high currents with excellent frequency response, then measurement capability is improved, but temperature drift and cost increase
Solution Approach 1:
The patent changes the fundamental measurement parameter from Hall effect voltage output to Rogowski coil voltage induction. By using electromagnetic induction principle with air core coil, the system achieves frequency response comparable to Hall sensors while eliminating temperature drift issues. The output signal characteristics are modified to be inherently more stable across temperature variations.
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 provides high sensitivity and adaptability, minimizing interference and power loss, enabling accurate measurement from milliamps to hundreds of kiloamps with low manufacturing costs and stability across varying frequencies and temperatures, while preventing adverse effects from short circuits and surge currents.
Implementation Method 1
The functioning principle of the Rogowski coils is based on the coil with an air core placed around the conductor in such a way that the magnetic field produced by the current, which flows through the conductor, induces voltage in the coil.
Implementation Method 2
The transducer is designed in a multi-layer printed circuit board geometrically compensated to reject the influence of external fields
Data Source
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AI summary
The active linear current transducer based on the use of the Rogowski principle and characterised by building a coil on a printed circuit board, integrating the conditioning electronicsof the signal jointly with the coil, which is all under the housing. Thanks to the designed transducer, it is possible to achieve the measurement from mA until several hundreds of kA, it also prevents any negative effect on the standard measurement devices; it also makes it possible to obtain a response in case of short circuit or surge current, since it lacks an iron core, it presents good linearity even when high intensities are measured; it makes it possible to work in an extensive bandwidth and measure small signals of alternating current.