PCB Rogowski Coil Current Sensor for Compact Energy Measurement
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Solution Overview
Problem
Conventional current transformers used in current sensors are bulky and require significant internal spacing, making them difficult to incorporate into compact electronic devices like miniature circuit breakers, and they also involve complex mechanical installation.
Innovation Solution
A Rogowski coil type current sensor is implemented using electrically conductive traces on a printed circuit board (PCB) substrate, forming a conductive helix that resembles a Rogowski coil, reducing volume and simplifying installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional current transformers are used as current sensors, then current sensing function is achieved, but the device occupies large space and requires significant internal spacing
Solution Approach 1:
The patent replaces the mechanical current transformer structure with an electronic Rogowski coil implementation using PCB traces. The conductive traces are arranged in a spiral pattern on the PCB substrate, creating a planar current sensor that eliminates the need for bulky mechanical components while maintaining accurate current sensing through electromagnetic induction principles.
Solution Approach 2:
The invention transitions from a three-dimensional current transformer structure to a two-dimensional planar configuration. The PCB traces are laid out in a spiral pattern on the flat substrate surface, reducing the sensor from occupying significant internal spacing in 3D space to a compact 2D footprint that fits within constrained device dimensions.
2Ease of operation
If conventional current transformers are used, then current measurement capability is provided, but mechanical complexity increases and installation becomes difficult
Solution Approach 1:
The patent merges the current sensor functionality directly into the PCB structure by forming conductive traces that serve dual purposes: as electrical connection paths and as the sensing element itself. This integration eliminates separate mechanical components and simplifies installation to merely mounting the PCB assembly, reducing mechanical complexity while improving ease of operation.
Solution Approach 2:
The invention creates a simplified planar copy of the traditional Rogowski coil structure using PCB traces instead of wrapped wire loops. The spiral trace pattern replicates the essential electromagnetic sensing function of the conventional coil while eliminating the complex mechanical winding and assembly processes associated with traditional current transformers.
3Volume of stationary object
If PCB trace current sensor is used, then volume is reduced and installation is simplified, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes PCB manufacturing parameters such as trace width, trace spacing, and spiral geometry that can be precisely controlled during the PCB fabrication process. By designing the trace dimensions and spiral pattern to specific parameters, the sensor achieves accurate current measurement while maintaining a compact footprint, with manufacturing precision managed through standard PCB manufacturing tolerances.
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 PCB trace current sensor offers a reduced volume, low profile, easy installation, and lower production costs, with improved bandwidth for measuring higher currents without magnetic saturation.
Implementation Method 1
The Rogowski coil type current sensor provides an output signal, which is a voltage, that is proportional to the rate of change of the input signal, which is the line current
Data Source
AI summary
Systems and methods for sensing current provide a Rogowski coil type current sensor for a current flow monitoring device in which the coil windings are formed by electrically conductive traces on a printed circuit board (PCB) substrate. Each coil winding is composed of two or more elongate traces formed on a PCB substrate and extending radially outward from a central opening or hole in the PCB substrate. Each trace coil winding is connected to electrically conductive vias, one via at each end of the trace. The via at one end connects the trace to another trace in coil winding, while the via at the other end connects the trace to a different trace in the same coil winding or an adjacent coil winding. The result is a conductive helix encircling the central opening in the PCB substrate that electrically resembles a Rogowski coil.