Redundant Current Measuring Circuit with Hall Sensor
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Solution Overview
Problem
Current measuring circuits in high-voltage battery systems, such as those in electric vehicles, face challenges in accurately detecting faults in measuring resistors and shunt circuits due to small voltage drops and susceptibility to external interference, which can lead to undetected errors in current measurement.
Innovation Solution
A compact current measuring circuit integrating a magnetic field sensor on the evaluation circuit board, using both the measuring resistor and magnetic field sensor to provide redundant current measurement, with the magnetic field sensor detecting the magnetic field around the measuring resistor and a Hall sensor as the secondary signal, allowing for error detection by comparing primary and secondary signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a small shunt resistor is used to minimize power loss, then energy efficiency is improved, but the voltage drop becomes too small to measure accurately
Solution Approach 1:
The patent combines two different measurement principles (voltage measurement across shunt resistor and magnetic field measurement via Hall sensor) into a single evaluation circuit board. This merging allows the system to benefit from both methods simultaneously - the voltage measurement provides accurate primary data while the magnetic field measurement provides redundant secondary data, resolving the contradiction between minimizing power loss and maintaining measurement accuracy.
Solution Approach 2:
The Hall sensor acts as an intermediary measurement device that detects the magnetic field generated by the current without requiring a large voltage drop. This intermediary approach allows accurate current measurement while keeping the shunt resistor value low, thus minimizing power loss while maintaining measurement precision through a different physical principle.
2Reliability
If redundant measurement with magnetic field sensor is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the evaluation circuit and Hall sensor onto a single evaluation circuit board, integrating multiple functions into one unified device. This integration reduces the overall system complexity compared to having separate devices, while still providing redundant measurement capabilities through the combination of voltage sensing and magnetic field sensing.
Solution Approach 2:
The evaluation circuit board is designed with multi-functionality, serving both as the signal processing unit for the shunt resistor measurement and as the mounting platform for the Hall sensor. This universal design allows the same component to fulfill multiple roles, reducing the total number of separate components needed and simplifying the overall device architecture.
3Area of stationary object
If Hall sensor is integrated on evaluation circuit board, then compactness is improved, but susceptibility to external magnetic interference increases
Solution Approach 1:
The patent extracts the Hall sensor from the main evaluation circuitry by providing it with a separate mounting area on the evaluation circuit board. This spatial separation within the integrated board allows the Hall sensor to be positioned away from potential sources of magnetic interference generated by other circuit components, reducing susceptibility to external magnetic interference while maintaining compact integration.
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 solution enables precise and fault-tolerant current measurement with reduced power loss and improved immunity to external interference, ensuring reliable operation in high-voltage battery systems.
Implementation Method 1
a magnetic field sensor (20) arranged on the evaluation circuit board (18) for redundant measurement of the current flow through the measuring resistor (16) using a second measuring principle, wherein the magnetic field sensor (20) is designed to measure a magnetic field proportional to the current flow around the measuring resistor (16)
Implementation Method 2
The magnetic field sensor is located on the evaluation circuit board in addition to the evaluation circuitry and is designed to measure a magnetic field proportional to the current flow around the measuring resistor – preferably, the magnetic field sensor is implemented as a Hall sensor.
Data Source
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AI summary
A current measuring circuit for redundantly measuring electrical current using a measuring resistor (16), a magnetic field sensor (20) and an evaluation circuit on an evaluation circuit board (18) is proposed, wherein the evaluation circuit is used to determine electrical current using the measuring resistor (16). Characteristically, the magnetic field sensor (20) on the evaluation circuit board (18) and the evaluation circuit board (18) are arranged in direct proximity to the measuring resistor (16), with the result that the magnetic field sensor (20) can detect the magnetic field from the current-carrying resistor (16). In addition, a battery (14) with the current measuring circuit and a motor vehicle with the battery (14) are proposed.