Current Sensor Variable Supply Analog Control Loop Zero-Crossing
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Solution Overview
Problem
Current sensors face limitations in accurately detecting a currentless state and zero-crossing due to non-linear association between magnetic field strength and flux density, and are often restricted to specific current ranges, with existing solutions either being prone to interference or requiring digital signal processing that increases costs and reduces reliability.
Innovation Solution
A current sensor system utilizing a Hall sensor or AMR sensor with a variable supply and differential amplifiers to form an analog control loop, allowing for precise detection of currentless states by adjusting operating current or supply voltage to maintain constant Hall voltage, thereby enhancing sensitivity and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is used with a magnetically conductive ring to focus the magnetic field, then measurement precision is improved, but the association between magnetic field strength and flux density becomes non-linear, limiting the current range
Solution Approach 1:
The patent applies dynamics by making the operating current supplied to the Hall sensor variable rather than fixed. The control unit dynamically adjusts the operating current based on the detected magnetic field strength, allowing the sensor to maintain optimal sensitivity across a wide current range while preserving measurement precision through adaptive parameter adjustment.
Solution Approach 2:
The patent implements parameter changes by varying the operating current of the Hall sensor according to the measured magnetic field conditions. This allows the sensor's sensitivity to be dynamically optimized for different current magnitudes, resolving the non-linearity issue and expanding the usable current range while maintaining measurement accuracy.
2Measurement precision
If a compensation current transformer with a winding is used to regulate the magnetic field to zero, then measurement precision is improved, but the device complexity increases due to additional windings and regulation circuits
Solution Approach 1:
The patent extracts the complex compensation winding structure from the design and replaces it with a simpler approach using a Hall sensor combined with a magnetically conductive ring. The magnetic field focusing function is achieved through the ring's geometry and material properties rather than through complex wound structures, significantly reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent substitutes the mechanical/wound compensation structure with a magnetic field focusing approach using a magnetically conductive ring. This replacement eliminates the need for complex windings and manual regulation mechanisms, achieving precise measurement through the ring's inherent magnetic properties combined with electronic control of the Hall sensor.
3Adaptability or versatility
If digital signal processing is used to process Hall sensor signals, then adaptability is improved, but manufacturing costs increase and reliability decreases
Solution Approach 1:
The patent substitutes digital signal processing with an analog evaluation circuit that directly processes the Hall sensor output. This analog approach eliminates the need for complex digital processing chains, reducing manufacturing costs and improving reliability by minimizing conversion steps and digital processing requirements while maintaining sufficient adaptability for various current measurement applications.
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
Enables reliable and rapid detection of zero-crossing and currentless states, preventing overheating and reducing manufacturing costs, while improving sensitivity for temporally variable magnetic fluxes, allowing for efficient operation in a wide range of alternating voltage frequencies.
Implementation Method 1
a magnetic field generated by the current flow in a conductor can be measured with a Hall sensor alone
Implementation Method 2
If such a ring-shaped current sensor surrounds a conductor, the magnetic field generated by the conductor can be focused and the current flow in the conductor can be determined more precisely
Data Source
AI summary
A current sensor having a magnetic field sensor, and a variable current source connected to the magnetic field sensor, and a first differential amplifier, connected to the magnetic field sensor, for amplifying a first sensor voltage. A second differential amplifier is provided and the second differential amplifier is connected to the first differential amplifier and to the current source. In the case of the first sensor voltage, a first operating current is present at the magnetic field sensor and in the case of a second sensor voltage, a second operating current is present, whereby the second Hall voltage is smaller than the first sensor voltage and the second operating current is greater than the first operating current.