Converter Current Sensor Fault Detection Before Main Relay Connection
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Solution Overview
Problem
Existing methods for detecting current sensor failures in electric vehicle converters are limited, either failing to detect stuck currents within normal ranges or increasing costs due to the use of multiple sensors.
Innovation Solution
A method using a single current sensor in a converter that calculates a reference current value based on the voltage of a high voltage battery and the resistance of a pre-charge relay, comparing it with the sensing current value to detect failures, allowing detection before connecting to the main relay and reducing PCB area and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two current sensors are used to detect current sensor failure, then the reliability of failure detection is improved, but the device complexity and cost increase
Solution Approach 1:
The current sensor detects its own failure by comparing its output signal with a reference current value calculated from the control unit using battery voltage and pre-charge relay resistance, eliminating the need for additional sensors
Solution Approach 2:
The control unit acts as an intermediary by calculating the reference current value based on battery voltage and pre-charge relay resistance, which is then compared with the current sensor output to detect failures
2Reliability
If two current sensors are used to detect current sensor failure, then the reliability of failure detection is improved, but the product price increases
Solution Approach 1:
The current sensor detects its own failure through self-diagnosis by comparing its output with a calculated reference value, eliminating the need for expensive additional sensors
Solution Approach 2:
Instead of using a physical copy (second sensor), the system creates a virtual reference current value through calculation from battery voltage and pre-charge relay resistance for comparison
3Device complexity
If the slope of current sensor level is used to detect failure, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The control unit calculates a reference current value based on battery voltage and pre-charge relay resistance, serving as an intermediary standard for accurate failure detection
Solution Approach 2:
The detection method changes from monitoring current slope to comparing current magnitude against a calculated reference value, improving detection accuracy for stuck current conditions
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
Effectively detects current sensor failures before vehicle operation, reducing PCB area and costs by using a single sensor, ensuring reliable vehicle control and maintaining price competitiveness.
Implementation Method 1
a pre-charge relay for connecting the high voltage battery and the converter and reducing a potential difference between the high voltage battery and the converter
Data Source
AI summary
The present disclosure relates to a failure detection method for detecting a failure of a current sensor in a converter. A failure detection method of a current sensor in a converter includes recognizing a voltage value of a high voltage battery associated with a vehicle, calculating a reference current value of the converter associated with the high voltage battery based on the recognized voltage value of the high voltage battery and a resistance value of a pre-charge relay, obtaining a sensing current value from the current sensor in the converter, and detecting whether the current sensor in the converter fails using the calculated reference current value and a sensing current value obtained from the current sensor.