Split-Shunt Current Sensing With Analog-Digital Fault 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 over-discharge.
Innovation Solution
A current sensing module with a shunt resistor comprising two resistive parts and separate digital and analog sensing circuits, which provide digital and analog measuring values to a management system for determining the shunt resistor's functionality and triggering alarms if failures are detected, allowing for reduced power operations and user alerts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single current sensing module is used to monitor battery current, then the device complexity is low, but the reliability is insufficient due to inability to perform failure diagnosis
Solution Approach 1:
The shunt resistor is divided into two separate resistive parts (first resistive part and second resistive part) that are connected in series. Each resistive part is monitored by separate sensing circuits (first current sensing circuit and second current sensing circuit), allowing independent failure diagnosis. This segmentation enables the system to detect which specific part has failed while maintaining overall system functionality.
Solution Approach 2:
A management system acts as an intermediary that receives measuring values from both sensing circuits, compares them to detect failures, and generates alarm signals. This intermediary component coordinates the failure diagnosis process by analyzing the relationship between the two measuring values and determining when a failure has occurred.
2Measurement precision
If separate digital and analog sensing circuits are used to measure current from different resistive parts, then the measurement precision and failure diagnosis capability are improved, but the device complexity increases
Solution Approach 1:
The management system performs multiple functions: it receives measuring values from both sensing circuits, compares them to detect failures, generates alarm signals, and controls power supply to the motor. This multi-functional approach consolidates what could be separate components into a single system, reducing overall device complexity while maintaining measurement precision and failure diagnosis capability.
Solution Approach 2:
The digital sensing circuit and analog sensing circuit are merged into a unified current sensing module that shares common components such as the shunt resistor structure and management system. This merging allows both digital and analog measurement approaches to coexist and cross-validate each other, improving measurement precision and enabling failure diagnosis without proportionally increasing device complexity.
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 measurement and failure diagnosis of the shunt resistor, ensuring reliable battery monitoring and improved product reliability and safety by preventing common-cause failures and alerting users to maintenance needs.
Implementation Method 1
a shunt resistor which includes two resistive parts... the first current sensing circuit is coupled to the first resistive part of the shunt resistor for measuring a first current... the second current sensing circuit is coupled to the second resistive part of the shunt resistor for measuring a second current
Data Source
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AI summary
A current sensing module (100) includes a shunt resistor (10) for receiving and sensing a current (Ib), a digital sensing circuit (20), and an analog sensing circuit (30) . The shunt resistor (10) includes a connecting part (10C), a first resistive part (10A) and a second resistive part (10B) coupled in series to the first resistive part (10A) via the connecting part (10C). The digital sensing circuit (20) measures a first analog voltage (V1) of the first resistive part (10A) when the current (Ib) flows through the first resistive part (10A), and provides a first digital measuring value (I1d) associated with the first analog voltage (V1). The analog sensing circuit (30) measures a second analog voltage (V2) of the second resistive part (10B) when the current (Ib) flows through the second resistive part (10B), and provides a second analog measuring value (V2a) associated with the second analog voltage (V2).