Current Sensor Thermal Compensation Using Batch Characterization Data
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Solution Overview
Problem
Current methods for calculating thermal compensation of current sensors are time-consuming and not feasible for continuous mass production, as they require introducing each sensor into a temperature-varying chamber for calibration, which is impractical for high-volume production in the electric vehicle industry.
Innovation Solution
A method that uses batch characterization data of shunt resistors, where the resistance versus temperature behavior is pre-measured and stored, allowing for thermal compensation calculation without the need for individual sensors to be tested in a temperature-varying chamber, by using an electronic control unit to adjust for temperature variations based on ambient temperature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each current sensor is introduced into a temperature-varying chamber for individual calibration, then thermal compensation accuracy is improved, but production time and manufacturing complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the temperature-resistance behavior of shunt resistors in batches before they are installed in current sensors. The characterization data is obtained in advance and stored in the electronic control unit, eliminating the need for individual sensors to undergo time-consuming temperature-varying chamber calibration during production.
Solution Approach 2:
The patent uses copying by creating a digital model of the temperature-resistance relationship through characterization data that represents the thermal behavior of the shunt resistor material. This digital copy is stored in the electronic control unit and used to calculate thermal compensation, replacing the physical process of individual sensor calibration in temperature-varying chambers.
2Reliability
If individual current sensors are calibrated in temperature-varying chambers, then thermal compensation is improved, but manufacturing complexity and process time increase
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the temperature-resistance behavior of shunt resistors in batches before they are installed in current sensors. The characterization data is obtained in advance and stored in the electronic control unit, eliminating the need for individual sensors to undergo time-consuming temperature-varying chamber calibration during production.
Solution Approach 2:
The patent replaces the mechanical/physical calibration process using temperature-varying chambers with an electronic calculation system. The electronic control unit uses stored characterization data and ambient temperature measurements to calculate thermal compensation, substituting the complex physical calibration infrastructure with a simpler electronic computation-based approach.
3Measurement precision
If temperature-varying chamber calibration is performed for each sensor, then measurement accuracy is improved, but testing time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the temperature-resistance behavior of shunt resistors in batches before they are installed in current sensors. The characterization data is obtained in advance and stored in the electronic control unit, eliminating the need for individual sensors to undergo time-consuming temperature-varying chamber calibration during production.
Solution Approach 2:
The patent uses copying by creating a digital model of the temperature-resistance relationship through characterization data that represents the thermal behavior of the shunt resistor material. This digital copy is stored in the electronic control unit and used to calculate thermal compensation, replacing the physical process of individual sensor calibration in temperature-varying chambers.
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
This approach significantly reduces testing time by eliminating the need for temperature-varying chamber calibration, enabling efficient thermal compensation calculation and facilitating mass production of current sensors for electric vehicles.
Implementation Method 1
The electronic control unit (ECU) of the current sensor is able to determine the intensity, current, by Ohm's Law: I = V / R. The voltage V is the voltage drop between the terminals of the shunt resistor.
Implementation Method 2
the resistance R of the current sensor is the resistance re-calculated by the electronic control unit as a function of the temperature at a precise moment
Data Source
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AI summary
Method for characterizing a current sensor to calculate a thermal compensation of a sensed current. The current sensor comprising an electronic control unit (ECU) and a shunt resistor. The shunt resistor manufactured from a portion of a batch of an alloy material. The method comprising the steps of: providing a shunt resistor and a batch characterization data of resistivity or resistance versus temperature Rbatch(T) linked to the shunt resistor, mounting the shunt resistor to the current sensor, measuring a reference temperature (T) at the current sensor, obtaining a measured resistance (RT) of the current sensor at the reference temperature (T); and storing in the electronic control unit (ECU): - the batch characterisation data Rbatch(T) linked to the shunt resistor; - the reference temperature (T) at the current sensor; and - the measured resistance (RT) of the current sensor at the reference temperature (T).