Current Sensor Waveform Adjuster for Zeroing Error
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Solution Overview
Problem
Current sensors with fluxgate sensor elements face challenges in setting the error signal and detection signal close to zero when no current is flowing, due to fluctuations in auxiliary current transformers and windings, making accurate zeroing adjustments difficult.
Innovation Solution
A current sensor design incorporating a ring-shaped main magnetic core with first and second fluxgate sensor elements, a signal generator for excitation signals, a detector for outputting a detection signal based on voltage differences, and a waveform adjuster connected to the detection windings, which adjusts the signal waveform using a series circuit with variable resistance and capacitance elements, allowing for precise zeroing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two auxiliary current transformers are made effectively the same with opposite winding directions, then the error signal should be close to zero when no main current flows, but fluctuations in manufacturing characteristics make it difficult to achieve accurate zeroing
Solution Approach 1:
The patent applies preliminary action by introducing a waveform adjuster that can pre-adjust the signal waveform from one auxiliary current transformer before it is combined with the other. This adjustment is performed in advance to compensate for manufacturing variations, allowing the error signal to be set close to zero despite fluctuations in auxiliary current transformer characteristics. The waveform adjuster modifies the signal characteristics (amplitude, phase, or shape) of one transformer's output to match the other, thereby achieving accurate zeroing without requiring perfect manufacturing consistency.
2Measurement precision
If the detection signal is maintained close to zero volts when no current flows, then accurate current measurement is improved, but this requires complex zeroing adjustment mechanisms
Solution Approach 1:
The patent applies parameter changes by using a waveform adjuster that can modify the signal waveform parameters (such as amplitude, phase, or shape) of one auxiliary current transformer's output. By changing these waveform parameters, the system can compensate for imbalances and maintain the detection signal close to zero volts. This approach provides a flexible and relatively simple mechanism for achieving accurate zeroing compared to more complex mechanical or structural adjustment mechanisms, as it relies on electronic signal processing rather than physical reconfiguration.
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 accurate measurement of current values by maintaining the detection signal close to zero volts and improving detection precision by reducing magnetic susceptibility, thus facilitating precise current measurement.
Implementation Method 1
a signal generator that outputs excitation signals to the first detection winding and the second detection winding to magnetize the first detection winding and the second detection winding with inverted phases
Implementation Method 2
a detector that outputs a detection signal whose amplitude changes in proportion to a current value of a current flowing in the detected object based on a difference between a first voltage signal generated in the first detection winding and a second voltage signal generated in the second detection winding
Data Source
AI summary
A current sensor includes: a magnetic core that surrounds a detected object; a first sensor with a first sub-magnetic core incorporated in the magnetic core and a first winding wound around the first sub-magnetic core; a second sensor with a second sub-magnetic core incorporated in the magnetic core and a second winding wound around the second sub-magnetic core in the opposite direction to the first winding; a signal generator outputting signals to magnetize the first and second windings with inverted phases; a detector outputting a detection signal whose amplitude is proportionate to a current in the detected object based on the difference between first and second voltage signals generated in the first and second windings; and a waveform adjuster that is connected to at least one of the first and the second windings and adjusts the waveform of a voltage signal generated by the connected winding.