EV Charging Pilot-Line Diagnostics for PE Fault Localization
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Solution Overview
Problem
Conventional electric vehicle charging systems and diagnostic methods fail to accurately differentiate and diagnose faults in the Protective Earth (PE) line, making it difficult to determine the location and nature of faults, which complicates maintenance and repair.
Innovation Solution
A vehicle charging diagnostic apparatus and method that uses a voltage sensor to detect negative voltage thresholds on the control pilot line and a current sensor to monitor characteristics on the proximity pilot line, allowing the diagnostic controller to identify and differentiate types of PE line faults, thereby providing indicators for fault location and nature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PE loss detection mechanisms are used, then safety protection is provided, but fault location and differentiation capabilities are insufficient
Solution Approach 1:
The patent segments the PE line into multiple sections (charging station to coupler, coupler to inlet, inlet to charge controller) and uses sectioned diagnostic signaling to identify which specific segment contains the fault. This allows precise fault localization rather than just detecting PE loss generally.
Solution Approach 2:
The patent introduces an intermediary diagnostic signaling mechanism that works through existing conductors (CP, PP, DC+, DC-) to provide fault detection capabilities without requiring additional dedicated diagnostic wires. The intermediary signals carry diagnostic information through the charging connection infrastructure.
2Measurement precision
If additional diagnostic capabilities are added to differentiate fault types, then fault location accuracy improves, but system complexity increases
Solution Approach 1:
The patent makes existing charging conductors multi-functional by using them for both power/communication purposes and diagnostic signaling. The CP, PP, DC+, and DC- lines serve their original functions while also carrying diagnostic information, eliminating the need for separate diagnostic wiring.
Solution Approach 2:
The patent uses parameter changes in existing signals (voltage levels, signal states on CP/PP lines) to encode diagnostic information. By varying signal parameters during charging operations, the system conveys fault location data without adding physical complexity.
3Ease of repair
If comprehensive fault diagnostics are implemented, then maintenance ease improves, but charging protocol complexity increases
Solution Approach 1:
The diagnostic system enables the charging infrastructure to self-diagnose faults automatically during charging operations. The system identifies and reports fault locations without requiring external diagnostic equipment or manual testing, providing self-service capability that simplifies maintenance.
Solution Approach 2:
The patent implements feedback mechanisms where diagnostic information flows back to the charging station and vehicle systems, enabling real-time fault identification. This feedback loop allows the system to automatically adjust operations based on detected faults and provide clear diagnostic information to operators.
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 detection and differentiation of PE line faults, facilitating straightforward repair operations and providing additional safety controls by stopping charging operations when faults are identified.
Implementation Method 1
a voltage sensor for determining the voltage on a control pilot line; and a diagnostic controller for identifying a first fault in response to detecting, using the voltage sensor, a negative voltage at or below a threshold
Implementation Method 2
In the event of a PE line fault, a diode in the CP line and the y-capacitance on the DC+ and DC- lines, creates a negative charge pump circuit effect on the CP line
Data Source
Figure 1~3
Figure 4~5
AI summary
Vehicle charging diagnostic apparatus including a voltage sensor (11) for determining the voltage on a control pilot line (5). A diagnostic controller (10) is provided for identifying a first fault in response to detecting, using the voltage sensor (11), a negative voltage at or below a threshold, such as -15V. A current sensor (12) may be provided for sensing the current on the proximity pilot line (6), with the diagnostic controller (10) identifying a further fault in response to detecting fluctuations in the current sensed by the current sensor (12).