Battery Current Measurement Offset Correction During Variable Charging
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Solution Overview
Problem
Existing methods struggle to correct the offset in current measurement devices when the charging/discharging current is constantly changing, making it difficult to determine the appropriate timing for offset correction.
Innovation Solution
A battery management system that includes an acquisition section for measuring the charging current, a current value calculation section to determine the current value, and a correction section that adjusts the offset based on the calculated current value and measurement value, allowing for offset correction even during changing currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset correction is performed using conventional methods (when current is zero or stable), then measurement accuracy is improved, but the method cannot be applied when charging/discharging current is constantly changing
Solution Approach 1:
The system performs preliminary calibration to establish the relationship between charger current and battery current, then uses this pre-established relationship to enable offset correction at any timing rather than requiring specific current conditions. This preliminary action allows the correction mechanism to function adaptively under varying current conditions.
Solution Approach 2:
The invention transitions from static offset correction (requiring zero or stable current) to dynamic offset correction by calculating the battery current based on the charger current and applying correction continuously or at arbitrary timings. This dynamic approach allows the correction to adapt to constantly changing charging/discharging conditions.
2Measurement precision
If offset correction timing is restricted to when current is zero or stable, then correction accuracy is improved, but correction opportunities are lost during constant current changes
Solution Approach 1:
The system continuously monitors both the charger current and the current measurement device output, compares the calculated battery current with the measured current, and performs offset correction based on this feedback. This feedback mechanism enables timely correction by detecting when correction is needed rather than relying on pre-defined timing conditions.
Solution Approach 2:
The system performs preliminary calibration to establish the current relationship, then uses this foundation to enable flexible timing selection for offset correction. This preliminary preparation allows the system to correct offsets at any timing including during constant current changes, eliminating missed correction opportunities.
3Measurement precision
If multiple current measurement devices are used (charger side and vehicle side), then measurement cross-validation is improved, but system complexity increases
Solution Approach 1:
The battery current calculation based on charger current acts as an intermediary reference that bridges the charger-side measurement and vehicle-side measurement. This intermediary calculated value enables cross-validation and offset correction without requiring direct complex interaction between multiple measurement devices, simplifying the overall system architecture.
Solution Approach 2:
The invention replaces the need for complex synchronization and direct comparison mechanisms between multiple physical measurement devices with a calculation-based approach. By calculating the expected battery current from charger current and comparing with the measurement device output, the system achieves cross-validation through computational means rather than complex mechanical/electrical synchronization.
Data Source
AI summary
Provided are a battery management system and a vehicle that correct an offset in a current measurement device even in a case where a charging/discharging current is constantly changing. The battery management system includes: an acquisition section that acquires, in a case where a charging current flowing from a charger to a battery is measured by a current measurement device, a measurement value measured by the current measurement device; a current value calculation section that calculates a current value of the charging current based on a known value of a current flowing from the charger; and a correction section that corrects an offset in the current measurement device based on the current value having been calculated and the measurement value.