Current Sensor Fault Detection via Paired Voltage-Current Correlation
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Solution Overview
Problem
Current battery systems require a second redundant current sensor for fault detection, which is not always feasible, especially in automotive applications where on-board diagnostics demand a two-sided rationality check for current sensor faults.
Innovation Solution
A method and system that utilize a single current sensor by comparing the ratio of changes in battery voltage and current samples over a predetermined number of samples to detect faults, using a controller to determine if the ratio is within an expected range for battery resistance or conductance, thereby identifying sensor faults without a secondary sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a second redundant current sensor is used for fault detection, then measurement precision and reliability improve, but device complexity and cost increase
Solution Approach 1:
The system uses the voltage sensor and battery electrical characteristics to perform self-diagnosis of the current sensor. The controller calculates expected current values from voltage measurements and compares them with actual current sensor readings, enabling the system to detect faults using its existing components rather than requiring additional redundant sensors.
Solution Approach 2:
The voltage sensor acts as an intermediary element that enables current sensor fault detection. By measuring voltage and using the known electrical characteristics of the battery and circuit, the system can infer current values and compare them with current sensor measurements, using the voltage measurement as a mediator to validate current sensor accuracy without needing a second current sensor.
2Reliability
If a second redundant current sensor is installed, then reliability of fault detection improves, but manufacturing cost and hardware requirements worsen
Solution Approach 1:
The voltage sensor performs multiple functions: it not only measures battery voltage for normal operation but also serves as a tool for current sensor fault detection. By utilizing the voltage sensor's measurements in conjunction with electrical characteristic data, the system achieves dual functionality from a single sensor, eliminating the need for redundant current sensors.
Solution Approach 2:
The system employs self-service diagnostics where the existing voltage sensor and controller work together to monitor and validate current sensor performance. The controller uses voltage measurements and electrical characteristic models to generate expected current values and compare them with actual readings, enabling the system to self-diagnose sensor faults without external redundant components.
3Measurement precision
If electrical characteristic data is collected and processed, then fault detection capability improves, but use of energy and computational load increase
Solution Approach 1:
The system performs preliminary actions by pre-storing electrical characteristic data (resistance values, capacitance values, temperature coefficients) in memory before fault detection is needed. This pre-prepared data eliminates the need for real-time complex calculations during fault detection, as the controller only needs to retrieve stored values and perform simple comparisons with current measurements.
Solution Approach 2:
The system changes parameters by using pre-characterized electrical values (resistance, capacitance, temperature coefficients) that are determined during manufacturing or initial operation. These fixed parameters are stored and reused during fault detection, converting a potentially complex real-time calculation problem into a simpler comparison task that requires minimal computational energy.
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 reliable detection of current sensor faults in battery systems using a single sensor, improving efficiency and reducing hardware requirements, while maintaining compliance with automotive diagnostics standards.
Implementation Method 1
checking whether a ratio of the change in the battery voltage samples and the change in the battery current samples is within an expected range for one of (i) a resistance of the battery and (ii) a conductance of the battery
Data Source
AI summary
A method for current sensor fault detection in a battery system comprises receiving a sequence of battery voltage samples from a voltage sensor configured to measure a battery voltage of a battery and a sequence of battery current samples from a current sensor configured to measure a battery current of the battery; determining a change in the battery voltage samples over a predetermined number of samples and a change in the battery current samples over the predetermined number of samples; checking whether a ratio of the change in the battery voltage samples and the change in the battery current samples is within an expected range for one of (i) a resistance of the battery and (ii) a conductance of the battery; and detecting a fault in the current sensor based on whether the ratio is within the expected range.