EV Charging Contact Voltage Control via Current Monitoring

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Solution Overview

Problem

Electric vehicle charging devices pose a safety risk when unoccupied electrical contact means are live due to unintentional disconnection of charging cables, potentially injuring passers-by or operators.

Innovation Solution

A method and arrangement where the electrical contact means are initially switched off and only temporarily supplied with voltage when a vehicle is connected, using a current monitoring device to ensure voltage is applied only when current flows, and automatically disconnected if the connection is interrupted, with additional protection from circuit breakers for overcurrent and fault currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact means is continuously supplied with voltage to ensure ready-to-charge state, then the charging readiness is improved, but the safety risk increases due to unoccupied live contact means

Engineering Contradiction:
Improvecharging readinessVSAvoidsafety risk from live contact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary voltage supply to the contact means only when a vehicle is detected to be connected. The control unit activates voltage supply in advance of the actual charging need, but only after confirming vehicle presence through connection detection, thereby ensuring charging readiness while preventing unoccupied contact means from being live

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the connection status between the vehicle and charging device, and adjusts voltage supply accordingly. When the vehicle is connected, voltage is supplied; when disconnected, voltage is cut off. This feedback mechanism ensures the contact means is only live when occupied, resolving the safety risk while maintaining charging readiness

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the contact means is switched off when no vehicle is connected to eliminate safety risks, then the safety is improved, but the charging readiness deteriorates

Engineering Contradiction:
Improvesafety from live contactVSAvoidcharging readiness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system activates voltage supply in advance when vehicle connection is detected, ensuring the contact means is ready for immediate charging. The control unit monitors connection status and switches on voltage before charging actually begins, maintaining readiness without leaving the contact means permanently live

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The voltage supply state of the contact means is made dynamic rather than static. The system transitions between switched-off and voltage-supplied states based on real-time vehicle connection status, allowing the contact means to be safe when unoccupied and ready when occupied

Inventive Principle:
Principle #15Dynamics

3Reliability

If the charging cable is unintentionally disconnected during charging, then the cable safety is improved, but the contact means remains live creating a safety hazard

Engineering Contradiction:
Improvecable connection stabilityVSAvoidlive unoccupied contact hazard
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control unit continuously monitors the connection status during charging and automatically cuts off voltage supply when disconnection is detected. This feedback mechanism ensures that if a cable is unintentionally pulled out, the contact means is immediately de-energized, eliminating the safety hazard while allowing stable charging when connected

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2611645B1Method and arrangement for supplying voltage to an electrical contact-forming means
Publication Date: 2015.04.29 SIEMENS AG
  • EP2611645B1 patent drawingFigure 1
  • EP2611645B1 patent drawingFigure 2

AI summary

The invention relates to a method for supplying voltage to an electrical contact-forming means, in particular a plug socket, for connecting an electrically operated vehicle (23). In this method, the contact-forming means (12) is initially switched to a voltage-free state. During the activation (35) of a switch, the contact-forming means (12) is temporarily supplied with voltage. A current-monitoring device (32) is used to monitor whether electrical current flows through the contact-forming means (12), and the contact-forming means (12) continues to be supplied with voltage only when the current flows.