Dual-Path Shunt Current Sensing for EV Failure Diagnosis
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Solution Overview
Problem
Current sensing modules in electric vehicles fail to perform failure diagnosis during current sensing operations, which is crucial for accurate battery state monitoring and preventing overcharge or overdischarge.
Innovation Solution
A current sensing module comprising a shunt resistor with two resistive parts and both analog and digital sensing circuits, where the management system determines the functionality of the shunt resistor by comparing digital and analog measuring values, and reduces operations of the charging circuit and motor when a failure is detected, outputting an alarm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensing circuit is used for current measurement, then the device complexity is reduced, but the reliability of current sensing and failure diagnosis capability deteriorates
Solution Approach 1:
The shunt resistor is divided into two separate resistive parts (first resistive part and second resistive part), each measured by independent sensing circuits. This segmentation allows separate measurement paths that can be cross-checked for failure diagnosis, resolving the contradiction by maintaining simple individual circuits while achieving reliable combined measurement through redundancy
Solution Approach 2:
The system measures different voltage parameters (first analog voltage across the first resistive part, second analog voltage across the second resistive part) using different sensing circuits. By changing the measurement parameter approach from single-voltage to multi-voltage measurement, the system achieves both simplicity and reliability through comparative analysis of these parameters
2Reliability
If dual sensing circuits are implemented for failure diagnosis, then the reliability improves, but the device complexity increases
Solution Approach 1:
The shunt resistor is segmented into two resistive parts that can be measured independently. This segmentation enables failure diagnosis by comparing measurements from different parts, achieving reliability improvement without requiring complex redundant circuits throughout the entire sensing system
Solution Approach 2:
The management system acts as an intermediary that receives measurements from both sensing circuits, compares the first and second analog voltages, and determines shunt resistor functionality. This intermediary approach allows simple sensing circuits to achieve reliable failure diagnosis through centralized comparative analysis
3Device complexity
If the shunt resistor is measured by a single circuit, then the device complexity is reduced, but the measurement precision for failure diagnosis deteriorates
Solution Approach 1:
The shunt resistor is divided into two resistive parts, each measured by a separate sensing circuit. This segmentation provides multiple independent measurement data points that can be compared for failure diagnosis, achieving measurement precision improvement without requiring a single complex high-precision circuit
Solution Approach 2:
The management system compares the first analog voltage and second analog voltage measurements and uses this feedback to determine shunt resistor functionality. This feedback mechanism enables precise failure diagnosis by detecting discrepancies between the two measurement paths, achieving measurement precision without complex individual circuits
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 current sensing and failure diagnosis of the shunt resistor, ensuring reliable battery monitoring and improving product reliability and driving security by preventing common-cause failures.
Implementation Method 1
a shunt resistor for receiving and sensing the current... when the current flows through the second resistive part... when the current flows through the first resistive part
Data Source
AI summary
A current sensing module includes a shunt resistor for receiving and sensing a current, a digital sensing circuit, and an analog sensing circuit. The shunt resistor includes a connecting part, a first resistive part and a second resistive part coupled in series to the first resistive part via the connecting part. The digital sensing circuit is coupled to the first resistive part for measuring a first analog voltage of the first resistive part when the current flows through the first resistive part, and providing a first digital measuring value associated with the first analog voltage. The analog sensing circuit is coupled to the second resistive part for measuring a second analog voltage of the second resistive part when the current flows through the second resistive part, and providing a second analog measuring value associated with the second analog voltage.