Current Measuring Device Ground Connection for Voltage Saturation
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Solution Overview
Problem
Current current measuring devices for energy storage devices experience reduced measurement accuracy due to input voltage saturation, which occurs when the input voltage exceeds its allowable value, leading to errors in current measurement.
Innovation Solution
A current measuring device with a measuring resistor positioned on the current path, featuring a pair of detection points and a ground connection point connected to a common ground, where the resistance from one detection point to the ground connection point is minimized to prevent voltage saturation, ensuring accurate current measurement even at high currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shunt resistor is used for current measurement, then current measurement function is achieved, but measurement accuracy decreases when input voltage exceeds allowable value due to saturation
Solution Approach 1:
The patent divides the voltage measurement function into two separate measurement paths: one for measuring the voltage across the shunt resistor (via detection points) and another for measuring the voltage from detection points to ground (via ground connection points). This segmentation allows each path to operate within its own voltage range, preventing saturation of the differential amplifier even when total ground voltage is high.
Solution Approach 2:
The patent introduces ground connection points as intermediary connection points between the shunt resistor and ground. These ground connection points serve as reference points that allow the differential amplifier to measure only the voltage difference across the shunt resistor, effectively mediating the high voltage environment and protecting the amplifier from saturation.
2Ease of operation
If ground connection point is provided for shunt resistor, then current measurement is enabled, but voltage saturation occurs reducing measurement accuracy
Solution Approach 1:
The patent applies local quality by making different parts of the shunt resistor serve different functions: the detection points are positioned specifically to measure the voltage across the resistor for current calculation, while the ground connection points are positioned to provide stable ground references. This localized functional differentiation ensures that each measurement path operates optimally without interference.
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 configuration enhances current measurement accuracy by preventing input voltage saturation, thereby reducing measurement errors and improving the accuracy of current detection, especially at maximum currents.
Implementation Method 1
a measuring resistor positioned on a current path and having a resistor... configured to detect a current of the energy storage device from a voltage difference between the pair of detection points
Data Source
AI summary
A current measurement device 50 for measuring the current of a power storage element comprises a measurement resistor unit 80 that is positioned on a current path and comprises a resistor 81, a pair of detection points Pa, Pb that are positioned on the current path on both sides of the resistor 81, a current detection unit 160 that comprises a pair of voltage input units 161A, 161B that are connected to the pair of detection points Pa, Pb and detects the current of the power storage element from the voltage difference between the pair of detection points, and a ground connection point Pg that is connected to a common ground GND with the current detection unit 160. The resistance Rga along the current path X to the ground connection point Pg from the detection point Pa from among the pair of detection points Pa, Pb that is closest to the ground connection point Pg is smaller than the value obtained by dividing the input voltage tolerance Vm of the current detection unit 160 by a prescribed current of the power storage element.