Battery Current Sensor Offset Diagnosis Using Charge Balance
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Solution Overview
Problem
Current measurement using current sensors in battery-operated devices is prone to offset errors, leading to inaccurate modeling of battery states and erroneous time integration in battery models.
Innovation Solution
A method and apparatus for determining a current sensor offset by measuring battery current, creating a charge balance model, and using a central processing unit to correct the offset, enabling accurate battery state determination and predicting the remaining service life of the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sensor offset is not corrected, then device complexity remains low, but measurement precision deteriorates due to offset errors in battery current measurement
Solution Approach 1:
The system uses the battery model and charge balance calculations that are already necessary for battery state determination to automatically detect and diagnose current sensor offsets, without requiring separate dedicated diagnostic hardware or complex additional measurement systems
Solution Approach 2:
The system continuously monitors the charge balance derived from battery model calculations and uses deviations from expected charge balance (caused by sensor offsets) to generate feedback signals that trigger offset correction procedures
2Measurement precision
If current sensor offset is corrected using charge balance model, then measurement precision improves, but loss of time increases due to additional diagnosis and correction steps
Solution Approach 1:
The system performs charge balance calculations and offset diagnostics using data already collected during normal battery operation, rather than requiring separate dedicated calibration sessions or stopping device operation for correction
Solution Approach 2:
The offset correction process utilizes continuous battery operation data and model calculations that are already being performed for battery state management, transforming existing computational work into dual-purpose diagnostic information
3Reliability
If charge balance model is continuously monitored for offset detection, then reliability improves, but use of energy increases due to continuous calculation and monitoring
Solution Approach 1:
The charge balance model serves multiple functions simultaneously: it is used for both battery state determination (original purpose) and current sensor offset detection (diagnostic purpose), eliminating the need for separate dedicated diagnostic calculations
Solution Approach 2:
The battery management system's existing computational infrastructure and data processing capabilities are used to perform offset diagnostics, rather than requiring separate dedicated diagnostic hardware or computational resources
Data Source
AI summary
A method for determining a current sensor offset of a current sensor (47) in a device battery (41) of a technical device (4). In one example, the method includes measuring the battery current using the current sensor (47); providing (S1) a temporal profile of the battery current; recording (S2) a charge balance of the electrical charge amount flowing into the device battery (41) and out of the device battery (41) over time depending on the temporal profile of the battery current; creating (S2) or adjusting a charge balance model depending on a time-accumulated charge amount; and determining the current sensor offset depending on a local slope of the charge balance model at a specified time.