Current Detecting Device with Dual-Core Flux Cancellation
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Solution Overview
Problem
Conventional current detecting devices face noise interference due to the closed circuit configuration, which affects the accuracy of current measurement.
Innovation Solution
The device employs a dual-core configuration with opposing magnetic fluxes generated by first and second coils, canceling out induced electromotive forces and noise, using an excitation unit to apply a frequency-changing signal and a feedback unit to generate a feedback signal that opposes the magnetic flux, thereby suppressing noise in the conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single core with one coil is used for current detection, then the device structure is simple, but noise is superimposed in the closed circuit affecting measurement accuracy
Solution Approach 1:
The single core is divided into two separate cores (first core and second core), each with its own coil. This segmentation allows the magnetic flux paths to be separated, enabling the second coil to generate opposing magnetic flux that cancels out the noise-induced magnetic flux in the first coil, thereby improving measurement accuracy while maintaining reasonable structural complexity
Solution Approach 2:
The second core and second coil act as an intermediary element that generates a counteracting magnetic flux. This intermediary magnetic flux serves as a mediator to cancel out the harmful noise-induced flux in the first core, allowing accurate current measurement without directly modifying the conductor or detection circuit
2Ease of operation
If AC excitation voltage is applied to the coil in a closed circuit configuration, then current detection is enabled, but induced current generates noise terminal voltage
Solution Approach 1:
The second coil is configured to generate magnetic flux in advance that opposes the magnetic flux generated by the AC excitation voltage in the first coil. This preliminary anti-action cancels out the induced electromotive force and prevents noise terminal voltage from being generated in the closed circuit, allowing AC excitation to be applied without harmful noise effects
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 effectively suppresses noise in the closed circuit, improving the accuracy of current measurement by canceling out induced electromotive forces and reducing noise interference.
Implementation Method 1
an excitation unit configured to apply an excitation signal, having a magnitude and a direction that change at a given frequency, to the first coil and the second coil
Implementation Method 2
when a magnetic flux is generated on the periphery of the conductor by a current flowing in the conductor that passes through the core
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A first coil (10) is wound around a first core (1), and have one end that is connected to ground and the other end that is connected to one end of a second coil (20). The second coil (20) is wound around a second core (2), and has the one end that is connected to the first coil (10), and the other end that is connected to an excitation unit (3) via a current-limiting resistor (R1). A magnetic flux is generated in the first core (1) by an excitation signal outputted from the excitation unit (3). Induced electromotive force is generated in the conductor (100) due to the magnetic flux generated in the first core (1). However, the direction of the magnetic flux generated in the second core (2) is opposite to the direction of the magnetic flux generated in the first core (1), and the induced electromotive forces of them generated in the conductor (100) are cancelled each other out. As a result, noise (noise terminal voltage) that is superimposed in a closed circuit including the conductor (100) can be suppressed.