EV Charging Disconnection Using Star-Point Voltage Fault Detection
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Solution Overview
Problem
Existing EVSE systems rely on local earth electrodes for fault protection, which can degrade over time, leading to inconsistent earthing performance and potential electrocution risks due to open neutral events, especially in TN earthing systems.
Innovation Solution
A detection system that creates a star point from a multi-phase power source, measures voltage differences between the star point and neutral or earth conductors, and automatically disconnects the vehicle charging interface if the voltage difference exceeds a threshold, providing enhanced fault protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a local earth electrode is installed for EVSE, then earthing protection is provided, but the earthing performance degrades over time due to corrosion leading to inconsistent protection
Solution Approach 1:
The patent introduces a detection system as an intermediary between the power source and the vehicle charging interface. This detection system monitors voltage differences between phases and neutral/earth conductors, and can disconnect the charging interface through a disconnector without relying on the long-term reliability of the local earth electrode. The detection system acts as a mediator that provides fault protection through active monitoring rather than passive earthing alone.
Solution Approach 2:
The patent implements a feedback mechanism where the detection system continuously monitors the electrical conditions (voltage differences between phases and neutral/earth conductors) and provides feedback control through the disconnector. When abnormal voltage differences indicating neutral breaks or earth faults are detected, the system automatically disconnects the charging interface, creating a closed-loop protection system that compensates for earth electrode degradation.
2Ease of manufacture
If reliance is placed on local earth electrode for fault protection, then simple installation is required, but electrocution risk increases when neutral conductor breaks
Solution Approach 1:
The detection system serves as an intermediary monitoring layer that detects neutral breaks and earth faults by measuring voltage differences between phases and neutral/earth conductors. When faults are detected, the disconnector intermediary component isolates the vehicle charging interface from the power source, providing active protection against electrocution risks without complicating the basic earthing installation.
Solution Approach 2:
The detection system performs preliminary detection of potential hazards (neutral breaks, earth faults) before they can cause electrocution. By continuously monitoring voltage differences and automatically disconnecting when abnormal conditions are detected, the system takes preliminary protective action to prevent harmful events rather than relying solely on the passive earthing infrastructure.
3Reliability
If voltage-based detection system is implemented, then fault detection reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical earthing verification systems with an electrical voltage-based detection system. Instead of relying on physical inspection or complex earth resistance measurement equipment, the system uses simple voltage difference measurements between phases and neutral/earth conductors to detect faults. This substitution of measurement methodology achieves high reliability with relatively simple implementation.
Solution Approach 2:
The detection system is designed to perform multiple detection functions using a single integrated approach. It can detect neutral breaks, earth faults, and phase imbalances simultaneously by monitoring voltage differences between various conductors. The same detection mechanism and disconnector serve both protective disconnection and fault indication functions, reducing overall system complexity while maintaining high reliability.
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
Ensures reliable and immediate disconnection in case of neutral or earth faults, reducing the risk of electrocution and maintaining consistent earthing performance by bypassing reliance on a single local earth electrode.
Implementation Method 1
measure a voltage difference between the star point and a neutral conductor or an earth conductor
Data Source
AI summary
Electric vehicle supply equipment (100) comprising a detection system (102), wherein the detection system (102) is configured to: create a star point (104) from phases from a multi-phase power source (1); measure (124, 126, 306, 316) a voltage difference between the star point and a neutral conductor (N) or an earth conductor (E); and cause (320) a disconnector (106) to electrically disconnect a vehicle charging interface (208) of the electric vehicle supply equipment (100) from the multi-phase power source (1) in dependence on the voltage difference exceeding a threshold.