Calibrating Current Measuring Resistor via Self-Heating
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Solution Overview
Problem
Current methods for calibrating current measuring devices with measuring resistors are complex, costly, and time-consuming, particularly due to the need for temperature chambers that can ineffectively heat or cool the entire device, rather than targeting specific components.
Innovation Solution
A method where a measuring resistor is calibrated by applying a first reference current to determine a voltage drop at a first temperature, and then heated to a second temperature using a second reference current, with the temperature change achieved solely by the reference current, allowing for efficient and targeted heating of the resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature chambers are used to calibrate the current measuring device at different temperatures, then measurement accuracy at various temperatures is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the temperature change function from the entire current measuring device and applies it only to the measuring resistor. By using the reference current to heat only the measuring resistor rather than the entire device in temperature chambers, the calibration system complexity is reduced while maintaining measurement accuracy at different temperatures.
Solution Approach 2:
The invention applies local quality by heating only the measuring resistor (a specific local component) rather than the entire current measuring device. The reference current is directed specifically to the measuring resistor to create temperature changes at that location, allowing temperature-dependent calibration without the need for comprehensive temperature chambers.
2Measurement precision
If temperature chambers are used to heat or cool the entire current measuring device, then temperature-dependent measurement accuracy is improved, but calibration time increases
Solution Approach 1:
The invention extracts the temperature control function from the entire device level to the component level (measuring resistor only). By applying reference current directly to the measuring resistor, temperature changes are achieved rapidly at the specific location without the time-consuming process of heating or cooling the entire device in temperature chambers.
Solution Approach 2:
The invention uses periodic application of reference current pulses to the measuring resistor to achieve the desired temperature changes. By controlling the duration and amplitude of these current pulses, the measuring resistor can be rapidly heated to target temperatures and then allowed to cool, significantly reducing calibration time compared to thermal chamber methods.
3Productivity
If multiple temperature chambers are used in parallel to increase calibration throughput, then productivity is improved, but device complexity and cost increase
Solution Approach 1:
The invention enables the measuring resistor to self-heat through the application of reference current, eliminating the need for external temperature chambers. By controlling the reference current parameters (amplitude, duration), the same calibration system can rapidly sequence through multiple temperature points on a single resistor, achieving high throughput without requiring multiple parallel chambers.
4Measurement precision
If the entire current measuring device is heated in temperature cabinets, then temperature calibration is achieved, but energy efficiency deteriorates due to unnecessary heating of non-target parts
Solution Approach 1:
The invention applies energy efficiently by heating only the measuring resistor (the specific component requiring calibration) rather than the entire current measuring device. The reference current is directed specifically to the measuring resistor, creating localized heating that consumes minimal energy while achieving the necessary temperature changes for accurate calibration.
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 simplifies and accelerates the calibration process, reducing costs and optimizing calibration time by using the reference current to heat the measuring resistor, thereby improving measurement accuracy without unnecessary heating of the entire device.
Implementation Method 1
the measuring resistor being heated from the first temperature to the second temperature by the first and / or second reference current
Data Source
AI summary
A method for calibrating a current measuring device (1), wherein the current measuring device (1) comprises a measuring resistor (Rmess) as a sensor, wherein for calibration a first known reference current (Imess) is applied to the measuring resistor (Rmess) to determine a first voltage drop across the measuring resistor (Rmess) at a first temperature, wherein for calibration at a second temperature different from the first temperature the measuring resistor (Rmess) is heated to the second temperature and a second known reference current (Imess) is applied to the measuring resistor (Rmess) to determine a second voltage drop across the measuring resistor (Rmess) at the second temperature, wherein the measuring resistor (Rmess) is heated from the first temperature to the second temperature by the first and/or second known reference current (Imess) and a current measuring device (1) configured to carry out such a method.