Battery Sensor Shunt Calibration via Reference Resistor
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Solution Overview
Problem
Existing battery sensors face challenges in accurately measuring current with low tolerance and high temperature drift, leading to increased power consumption and load on vehicle batteries due to the need for additional current pulses to detect high currents.
Innovation Solution
A battery sensor design that includes a measuring resistor and a reference resistor connected in parallel via a switch, allowing for calibration by alternately opening and closing the switch to calculate the resistance value without requiring a precise measuring resistor, thereby reducing power consumption by eliminating the need for additional current pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional current pulses are generated to detect high currents with sufficient resolution, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic calibration cycles where the switch is alternately opened and closed at predetermined intervals to measure the actual resistance value of the measuring resistor. During normal operation, the switch remains closed and no additional current pulses are generated, thus avoiding increased power consumption while maintaining measurement precision through periodic calibration.
Solution Approach 2:
The system uses the existing current flow through the measuring resistor to perform self-calibration by measuring voltage drops during switch state changes. The calibration process utilizes the operational current itself rather than requiring external test signals, eliminating additional power requirements while maintaining measurement accuracy.
2Measurement precision
If a highly stable measuring resistor material like copper-nickel-manganese alloy is used, then measurement precision and temperature stability are improved, but manufacturing cost and processing difficulty increase
Solution Approach 1:
The patent changes the approach from relying on material parameter stability to using electrical parameter measurement and calculation. Instead of requiring stable resistor materials, the system measures voltage drops across the measuring resistor during known switch state transitions and calculates the actual resistance value, allowing use of easier-to-process materials while maintaining precision.
Solution Approach 2:
The patent replaces the mechanical/material solution (using special stable alloys) with an electrical measurement and calculation approach. The actual resistance value is determined through electrical measurements during calibration cycles rather than relying on inherent material stability, enabling use of conventional, easier-to-manufacture resistor materials.
3Measurement precision
If the switch is opened and closed during calibration periods to measure voltage drops, then resistance calibration is achieved, but device complexity increases
Solution Approach 1:
The switch serves multiple functions: it enables calibration by allowing open/closed state transitions for resistance measurement, and simultaneously acts as a normal circuit element during operational modes. This multi-functionality reduces overall device complexity compared to having separate calibration and operational switching mechanisms.
Solution Approach 2:
The existing switch in the circuit is utilized for dual purposes - normal circuit operation and calibration functionality. The calibration process leverages the switch's inherent capability to change states, eliminating the need for separate calibration switching mechanisms and reducing overall device complexity.
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 design enables accurate current measurement with reduced power consumption and thermal load, maintaining measurement precision across varying current ranges without the need for expensive, difficult-to-process materials like copper-nickel-manganese alloys.
Implementation Method 1
the current strength is typically determined via the voltage drop across the measuring resistor, which is realized when a current flows through the measuring resistor
Implementation Method 2
measuring the voltage drop across a sufficiently precise, known reference resistor
Data Source
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AI summary
The invention relates to a battery sensor in which a voltage is measured via a shunt resistor with alternating parallel connection of a reference resistor. Furthermore, the invention relates to a corresponding method and to a corresponding use.