EV Charging Cable Earthing Check Without Network Communication
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Solution Overview
Problem
Existing methods for controlling electric vehicle charging processes are complex and require additional electronic equipment for communication with the power network to determine the type of network configuration, making it difficult to ascertain and adapt to TN, TT, or IT networks without proper communication means.
Innovation Solution
A method that measures resistance between network contacts and a protective conductor to identify network types, and applies a time-variable voltage to detect network configurations, enabling or disabling charging based on the integrity of the earthing, without the need for communication between the charging cable and the power network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If communication means (CAN bus technology) are provided to detect power network type, then the charging cable can identify TN, TT, or IT networks, but the device complexity increases due to additional electronic equipment
Solution Approach 1:
The patent extracts the communication protocol layer and replaces it with direct electrical measurement. Instead of using CAN bus communication to detect network type, the invention measures resistance directly between protective conductor and network contacts to determine whether the network is TN or TT type. This eliminates the need for complex communication electronics while achieving the same detection goal.
Solution Approach 2:
The patent replaces the electronic communication system (CAN bus) with an electrical measurement system. By substituting the mechanical/electronic communication protocol with direct resistance measurement, the invention simplifies the charging cable while maintaining network type detection capability.
2Device complexity
If no communication means are provided on the network side, then the charging cable cannot communicate with the network to ascertain network type, but the device complexity is reduced
Solution Approach 1:
The charging cable performs self-detection of the power network type by measuring resistance internally between its own contacts. Instead of requiring external communication infrastructure, the cable uses its own measurement capabilities to determine network configuration, making the system self-sufficient and eliminating dependency on network-side communication means.
Solution Approach 2:
The patent introduces resistance measurement as an intermediary method to bridge the gap between the charging cable and the power network. By measuring the electrical resistance between protective conductor and network contacts, the system can infer network type without requiring direct communication, serving as a mediator that enables detection in the absence of communication protocols.
3Device complexity
If resistance measurement is used to detect network type without communication means, then the charging cable can identify network configurations, but the measurement precision may be affected by earthing conditions
Solution Approach 1:
The patent implements a feedback mechanism where the measured resistance value is compared against predetermined thresholds to determine network type. The system continuously monitors the resistance between protective conductor and network contacts, and based on the measured value, it can reliably distinguish between TN (lower resistance) and TT (higher resistance) networks, compensating for variations in earthing conditions through threshold-based decision logic.
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 a universal charging cable to connect to differently configured power networks by reliably identifying network types and ensuring safe earthing, allowing charging processes to proceed only when protective earthing is intact, thus simplifying the charging process and eliminating the need for network-specific communication.
Implementation Method 1
ascertaining a resistance between a network contact and a protective conductor of a network connection
Implementation Method 2
This signal is transmitted to the network contact of the network connection via the protective earthing in a TN or TT network
Implementation Method 3
This signal is transmitted to the network contact of the network connection via the protective earthing in a TN or TT network
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates to a method for controlling a charging process of an electric vehicle. In a first step, a resistance between a network contact and a first protective earth conductor contact of a network connection is determined. In a second method step, the determined resistance is compared to a predetermined value. In a third method step, a time-variable voltage is applied to a vehicle connection. In a fourth method step, it is examined whether a time-variable signal, triggered by the time-variable voltage being applied to the vehicle connection, can be detected at the network connection. In a fifth method step, a charging process is enabled when either the determined resistance is below the predetermined value or the determined resistance is above the predetermined value and, at the same time, no time-variable signal can be detected at the network connection. The invention further relates to a charging cable, with which the method can be carried out.