EV Charging Current Sensor Merging for Weight Reduction
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Solution Overview
Problem
The existing systems for quick charging of electric vehicles require multiple current sensors to accurately detect abnormalities, leading to increased costs and vehicle weight due to the number of components needed.
Innovation Solution
A vehicle configuration that includes a connection wire, an electricity storage device, an auxiliary machinery load, a current sensor, and a control device to estimate inflow current, using contactors and a resistor to determine abnormalities without the need for dedicated current sensors, thereby reducing the number of components and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current sensors are provided to accurately detect abnormalities during quick charging, then measurement precision and reliability are improved, but device complexity, cost, and vehicle weight increase
Solution Approach 1:
The patent merges the functions of multiple current sensors into a single current sensor by combining the measurements of auxiliary machinery current with the single sensor's readings. The control device calculates total inflow current by adding the auxiliary machinery current (measured when disconnected) to the current sensor reading, thereby achieving accurate abnormality detection with fewer components
Solution Approach 2:
The control device acts as an intermediary that processes and combines data from the single current sensor with auxiliary machinery current measurements to derive accurate total current information. This intermediary computation allows the system to infer what multiple sensors would have detected without actually installing multiple sensors
2Reliability
If multiple current sensors are installed near the power receiving port and electricity storage device, then abnormality detection reliability is improved, but vehicle weight increases
Solution Approach 1:
The patent reduces vehicle weight by merging multiple current sensing functions into a single physical sensor. The system combines the single current sensor measurements with auxiliary machinery current data through control device calculations, achieving reliable abnormality detection without the weight penalty of multiple sensors
3Measurement precision
If multiple current sensors are provided to measure inflow and outflow currents separately, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent merges multiple current measurement functions into a single current sensor by strategically timing measurements. The auxiliary machinery current is measured when disconnected from the main circuit, and this measurement is combined with the current sensor readings during operation, achieving precise current measurement without requiring separate sensors for each measurement point
Solution Approach 2:
The system performs preliminary measurement of auxiliary machinery current when it is disconnected from the main circuit, before connecting it during normal operation. This preliminary measurement allows the control device to accurately calculate total current during charging without needing a separate sensor for the auxiliary machinery branch
Data Source
AI summary
A vehicle includes a connection wire which is provided at the vehicle, an electricity storage device, an external charging system, which charges the electricity storage device with power received from an external power supply through the connection wire, an auxiliary machinery load which is connected to the connection wire, a current sensor which measures au inflow current value into the electricity storage device and an outflow current value from the electricity storage device, an auxiliary machinery current consumption measurement unit which measures a current value to be consumed by the auxiliary machinery load, and a control device which, estimates the inflow current value from the external power supply based on a measurement result of the current sensor and a measurement result of the auxiliary machinery current consumption measurement unit while the electricity storage device is being charged with power received from the external power supply.