Electric Vehicle Drive-Chain Leakage Detection With Segmented Sensors
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Solution Overview
Problem
Conventional systems for detecting leakage currents in vehicles with electric drive systems fail to accurately identify the source of current leakage when an auxiliary converter is connected to multiple drive chains, leading to unnecessary disconnection of the entire system or unprotected drive chains.
Innovation Solution
A detection system with inlet and outlet current sensors for each drive chain, coupled with control means to process sensor data and identify the specific drive chain producing leakage, allowing independent disconnection of the affected chain without affecting others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary converter is connected to two independent drive trains to increase system availability, then the system can continue operating when one drive train fails, but the conventional leakage current detection system becomes unable to identify the source of leakage and may force disconnection of the entire system
Solution Approach 1:
The patent divides the detection function into separate inlet and outlet current sensors for each drive train, allowing independent measurement of current flow through each path. This segmentation enables the control means to identify which specific drive train is producing leakage current, rather than treating the entire system as a single detection unit.
Solution Approach 2:
The outlet current sensor acts as an intermediary element that measures current in the supply line and return line of the auxiliary converter. By positioning this sensor to detect current flowing through both lines, the system can calculate leakage current as the difference between supply and return currents, enabling precise identification of the leakage source.
2Measurement precision
If current detection sensors are installed at the inlet and outlet of each drive chain to enable precise leakage detection, then leakage source identification is possible, but the system complexity and installation cost increase
Solution Approach 1:
The outlet current sensor is designed to serve multiple functions: it measures the supply current to the auxiliary converter, measures the return current from the auxiliary converter, and enables leakage current detection. This multi-functionality reduces the total number of sensors needed compared to having separate sensors for each measurement point.
Solution Approach 2:
The patent combines the measurement of supply current and return current into a single outlet current sensor location. By merging these measurement functions at one point in the circuit rather than using separate sensors at multiple locations, the system reduces installation complexity while maintaining detection precision.
3Reliability
If the conventional differential protection system is used with the auxiliary converter connected to multiple drive trains, then the auxiliary converter can protect itself, but the drive chains remain unprotected and the entire system may be disconnected
Solution Approach 1:
The detection system is segmented to provide independent protection for each drive train. The control means can identify which specific drive train is producing leakage current and disconnect only that drive train, rather than forcing disconnection of the entire system. This allows the other drive train to remain operational and continue supplying the auxiliary converter.
Solution Approach 2:
The system uses feedback from the inlet and outlet current sensors to continuously monitor the electrical state of each drive train. When leakage current is detected, the feedback mechanism triggers the control means to disconnect only the affected drive train, providing targeted protection while maintaining system availability through the other drive train.
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
The system effectively detects and isolates leakage currents in individual drive chains, enhancing safety and reducing installation complexity and cost by ensuring independent protection for each converter.
Implementation Method 1
an inlet current sensor (5, 5') in the supply inlet line (1.1, 1.1') of each drive train (1, 1')
Implementation Method 2
an outlet current sensor (6, 6') arranged in each of the drive trains (1, 1') such that a supply line (4.1, 4.1') and a return line (4.2, 4.2') of the auxiliary converter, and a return line (1.2, 1.2') of the corresponding drive train (1, 1'), pass via said outlet current sensor
Data Source
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AI summary
The invention relates to a system for detecting leakage currents for drive systems of vehicles with an electric drive system with two or more traction converters (2, 2'), and with an auxiliary converter (4) fed by both drive chains (2, 2'), with the detection system comprising an inlet current sensor (5, 5') in the inlet line (1.1, 1,1') of each drive chain (1, 1'), and an outlet current sensor (6, 6') in each drive chain (1, 1') such that a supply line (4.1, 4.1') and a return line (4.2, 4.2') of the auxiliary converter, and a return line (1.2, 1.2') of the corresponding drive chain (1, 1') pass via said sensor (6, 6'), and with the detection system comprising control means which receive the information from the sensors (5, 5', 6 and 6') and identify which of the drive chains (1, 1') is producing a leakage current (Ifuga).