Leakage Detection Circuit Failure Diagnosis in EV Power Systems
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Solution Overview
Problem
Existing car power source apparatuses fail to accurately determine leakage detection circuit failure when leakage current occurs, leading to potential misjudgment and safety risks during maintenance of high-voltage systems in electric vehicles.
Innovation Solution
A car power source apparatus with a leakage detection circuit that includes a failure detection circuit to control and determine the status of leakage detection switches and resistors by measuring voltage ratios across different configurations, allowing for accurate identification of circuit failures even in the presence of leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If leakage detection switches are turned on to detect circuit failure, then the ability to detect switch/resistor failure is improved, but leakage current causes false positive failure detection
Solution Approach 1:
The detection process is segmented into multiple distinct steps: a first detection step with first detection switches connected to battery connection nodes, and a second detection step with second detection switches connected to other circuit nodes. This segmentation allows the system to isolate and differentiate between actual component failures and voltage changes caused by leakage current, preventing false positive detections while maintaining accurate failure detection capability.
2Power
If high voltage is used to increase output power, then the motor response and power output are improved, but the risk of electric shock during maintenance increases
Solution Approach 1:
The system performs preliminary leakage detection before allowing maintenance operations or power delivery. By continuously monitoring leakage current through the detection switches and control circuit, the system identifies potential safety hazards in advance and can disconnect or alert operators before electric shock occurs, thus preventing the harmful effect while maintaining high voltage operation.
Solution Approach 2:
The control circuit receives feedback signals from the detection switches indicating leakage current status. Based on this feedback, the control circuit automatically adjusts system operation - disconnecting power or alerting operators when leakage is detected - thereby maintaining safety during high-voltage operation through continuous monitoring and responsive control.
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 precise determination of leakage detection circuit failure, ensuring safe operation by distinguishing between actual failures and leakage current effects, thereby preventing unnecessary shutdowns and ensuring electrical safety.
Implementation Method 1
voltage detection circuits (4) to detect voltage at the first leakage detection resistors (12) and the second leakage detection resistors (22)
Data Source
AI summary
The car power source apparatus is provided with a leakage detection circuit 3 having a battery 1 with a plurality of battery units 2 connected in series, a first series circuit 11 made up of first leakage detection resistors 12 and a first leakage detection switch 13 to connect the first connection node 10 of the series connected battery units 2 to ground 9, a second series circuit 21 made up of second leakage detection resistors 22 and a second leakage detection switch 23 to connect the second connection node 20 of the series connected battery units 2 to ground 9, and voltage detection circuits 4 to detect voltage of the first leakage detection resistors 12 and the second leakage detection resistors 22. Further, the car power source apparatus is provided with a failure detection circuit 5 to control the first leakage detection switch 13 and the second leakage detection switch 23 ON and OFF and determine failure of the leakage detection circuit 3 from voltages detected by the voltage detection circuits 4.