PCB Fluxgate Fault Current Detection for EV Charging Stations

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Solution Overview

Problem

Current fault current detection systems in electric vehicle charging stations require substantial wiring and installation, are costly, and have limited resolution, accuracy, and noise, especially when detecting DC components.

Innovation Solution

An electrical circuitry with a fluxgate current sensor integrated on a printed circuit board, comprising conductive tracks and a magnetic core, allows for fault current detection without additional wiring by utilizing a magnetic core with a through-hole around the tracks, enhancing accuracy and reducing installation costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a RDC-DD device is installed inside the charging station housing together with the Type A RCD, then fault current detection capability is improved, but the wiring complexity and installation cost increase substantially

Engineering Contradiction:
Improvefault current detection capabilityVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the RDC-DD device and the Type A RCD into a single integrated unit with common housing, mounting structure, and wiring terminals. The fluxgate current sensor is integrated onto the same printed circuit board as the RCD control electronics, eliminating the need for separate wiring connections and reducing installation complexity while maintaining dual fault detection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device performs multiple functions: AC fault detection via the Type A RCD transformer, DC fault detection via the fluxgate current sensor, and unified circuit breaking through a single thermal-magnetic breaker. This multi-functional design eliminates the need for separate detection and protection devices, reducing wiring while improving reliability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a RDC-DD device is installed inside the distribution switchboard, then fault current detection capability is improved, but the installation cost and professional installation requirement increase

Engineering Contradiction:
Improvefault current detection capabilityVSAvoidinstallation cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The RDC-DD functionality is merged with the existing RCD unit, creating a single replaceable module that can be installed in the charging station without modifying the distribution switchboard. This integration eliminates the need for professional installation in the switchboard while maintaining DC fault detection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated RCD-RDC-DD unit is designed as a self-contained module with all necessary components (sensor, electronics, breaker) built-in, allowing it to be installed as a complete unit in the charging station rather than requiring separate installation of detection devices in the distribution switchboard

Inventive Principle:
Principle #25Self-service

3Reliability

If Type B RCDs are used to detect both AC and DC faults, then fault detection capability is improved, but the cost increases substantially

Engineering Contradiction:
Improvefault detection capabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of using a single expensive Type B RCD, the patent segments the detection function into two separate sensors: a Type A RCD transformer for AC faults and a fluxgate current sensor for DC faults. Each sensor is optimized for its specific detection task, allowing the use of lower-cost components that collectively provide comprehensive fault detection capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the detection parameter approach by using two different sensing mechanisms (transformer for AC, fluxgate for DC) rather than a single mechanism attempting to detect both. This parameter-based segmentation allows each sensor to operate in its optimal range at lower cost

Inventive Principle:
Principle #35Parameter changes

4Reliability

If conventional RDC-DD solutions are used, then DC fault detection capability is improved, but the resolution, accuracy, and noise performance worsen

Engineering Contradiction:
ImproveDC fault detection capabilityVSAvoidresolution and accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent uses a fluxgate current sensor, which is a sophisticated sensing technology that provides high-precision DC current measurement by detecting the magnetic field generated by the current. This advanced sensing approach copies the successful application of fluxgate technology from other precision measurement applications, delivering superior resolution and accuracy compared to conventional RDC-DD solutions

Inventive Principle:
Principle #26Copying

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 reliable, compact, and cost-effective fault current detection with high sensitivity and accuracy, reducing mechanical and thermal stress on the magnetic core, and minimizing space occupation in the charging station.

Implementation Method 1

The operation of RCDs relies on measuring the balance between the outgoing current in a live conductor and the returning current in a neutral conductor of an electrical circuit. Typical RCDs rely on the principle of a transformer to detect the presence of a magnetic field.

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a fluxgate current sensor for detecting a fault current in the at least two conductive tracks comprising a magnetic core with a through-hole arranged around the at least two conductive tracks passing through the through-hole of the magnetic core

Methodology Applied
Scientific EffectFluxgate sensing:

Data Source

PatentEP4429912B1Electric circuitry for fault current detection in an electric vehicle charging station
Publication Date: 2026.01.14 ENOVATES NV
  • EP4429912B1 patent drawingFigure 1
  • EP4429912B1 patent drawingFigure 2
  • EP4429912B1 patent drawingFigure 3A~3B

AI summary

An electrical circuitry for detecting a fault current in an electric vehicle charging station. The electrical circuitry comprises a printed circuit board, comprising at least two conductive tracks for conducting electrical charging currents for charging and/or discharging the electric vehicle along the printed circuit board. The electrical circuitry further comprises a fluxgate current sensor for detecting a fault current in the at least two conductive tracks, comprising a magnetic core with a through-hole arranged around the at least two conductive tracks passing through the through-hole of the magnetic core.