All-Current Residual Current Detection in EV Charging Plugs

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Solution Overview

Problem

Existing residual current devices are inadequate for detecting both AC and DC components in power supply networks, particularly in charging infrastructure for electric vehicles, leading to safety risks and inefficiencies, with type A devices being unsuitable for DC detection and type B devices being costly.

Innovation Solution

A compact residual current device integrating a magnetic-field-sensitive component, switching device, and control circuit for detecting both AC and DC components, allowing for efficient and safe operation in power supply networks, including charging systems for electric vehicles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If type A residual current devices are used to monitor AC power supply networks, then AC residual currents can be detected, but DC residual currents cannot be detected

Engineering Contradiction:

Improvedetection capabilityVSAvoidcurrent type coverage

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by designing a residual current device that can detect both AC and DC residual currents using a single integrated system. The magnetic field sensor and evaluation circuit are configured to process both alternating and direct current components, making the device versatile for different current types without requiring separate monitoring systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If type B residual current devices are used to detect both AC and DC components, then comprehensive residual current detection is achieved, but the cost increases significantly

Engineering Contradiction:

Improvecurrent type coverageVSAvoidcost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the evaluation circuit's processing parameters to selectively evaluate different current components. The circuit can be configured to detect AC components, DC components, or both, by adjusting detection thresholds and processing modes, thereby achieving versatile detection at lower cost through flexible parameter management rather than hardware complexity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If separate monitoring systems are used for AC and DC residual currents, then comprehensive detection is achieved, but device complexity increases

Engineering Contradiction:

Improvedetection completenessVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by integrating the AC and DC residual current detection functions into a single unified device. The magnetic field sensor captures both AC and DC components, and the evaluation circuit processes both types of currents through a unified processing path, eliminating the need for separate monitoring systems and reducing overall device complexity while maintaining detection completeness.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If residual current detection is implemented in charging infrastructure, then safety is improved, but the complexity of the charging system increases

Engineering Contradiction:

ImprovesafetyVSAvoidcharging system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the residual current device to autonomously monitor charging infrastructure safety without requiring external monitoring systems. The integrated sensor and evaluation circuit automatically detect residual currents and can trigger protective actions, making the charging system self-monitoring and reducing the need for additional complex safety infrastructure.

Inventive Principle:

Principle #25Self-service

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

Enables accurate and rapid detection of residual currents, ensuring safe and efficient charging by integrating the detection and switching functions into charging plugs, cables, and devices, reducing the need for separate monitoring systems and lowering costs.

Implementation Method 1

the sensor comprises a magnetic-field-sensitive component having a clearance through which the at least two power supply conductors are routed

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

at least one excitation and sensor winding which, with a plurality of turns, encloses the magnetic-field-sensitive component

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250341547A1Residual current operated device with all-current sensitive detection of differential currents and charging plug, in-cable control box, charging cable and charger therewith

Publication Date: 2025.11.06 MAGNETEC GMBH & CO KG

AI summary

A residual current device is configured for connection to a power supply network having at least two power supply conductors and includes a switching device for interrupting the at least two power supply conductors, a sensor for detecting residual currents in the at least two power supply conductors, and a control circuit which is designed to detect a residual current between the at least two power supply conductors using the sensor and, when a residual current is detected, to control the switching device to carry out a switching operation.