Dual Current Sensor Charge Control for EV Power Storage
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Solution Overview
Problem
Existing charge control systems for electric vehicles fail to simultaneously provide accurate full charge detection and reliable protection of power storage devices during external charging, as they either lack sufficient detection accuracy or cannot handle wide range and high-speed power calculations effectively.
Innovation Solution
A charge control device equipped with a current detection unit featuring first and second current sensors, where the first sensor provides a low-resolution detection value for protection control and the second sensor provides a high-resolution detection value for full charge control, along with a voltage sensor to determine the fully charged state, ensuring accurate and reliable power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current sensor is used for both protection control and full charge detection, then device complexity is reduced, but measurement precision deteriorates because one sensor cannot simultaneously provide both wide range/high-speed detection and high-resolution detection
Solution Approach 1:
The current detection unit is segmented into two separate current sensors: a first current sensor for protection control (providing wide range and high-speed detection) and a second current sensor for full charge detection (providing high-resolution detection). This segmentation allows each sensor to be optimized for its specific function, resolving the contradiction between device complexity and measurement precision.
2Device complexity
If a current sensor optimized for traveling power measurement is used during external charge, then device complexity is reduced, but measurement precision deteriorates because the sensor cannot provide sufficient detection accuracy for low-power external charging
Solution Approach 1:
Different current sensors are assigned to different operational contexts: the first current sensor handles high-power traveling conditions while the second current sensor handles low-power external charging conditions. This local quality approach ensures that each operational context receives the appropriate detection capability, resolving the contradiction between device complexity and measurement precision for different charging scenarios.
Data Source
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AI summary
A monitoring unit (54) outputs a first current detection value (IB1) having a relatively wide measurement range and a relatively short detection cycle and a second current detection value (IB2) having a relatively high resolution, to a charging ECU (48). When charging power calculated using the first current detection value (IB1) exceeds a predetermined limit value, the charging ECU (48) controls a charger (44) to reduce charging power (protection control). Further, the charging ECU (48) controls the charger (44) such that a power storage device (10) attains a predetermined fully charged state based on charging power calculated using the second current detection value (IB2) (full charge control).