Measuring method and device of pulse width detection type magnetic modulation direct current

A technology of direct current and measurement method, which is applied in the direction of measuring device, measuring current/voltage, measuring electrical variables, etc., can solve the problem of small test range, achieve the effect of simplifying the circuit, improving stability, and improving measurement accuracy

Active Publication Date: 2010-05-12
漳州市东南电子技术研究所有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the influence of these factors, the actual test range that can be realized by the ...

Method used

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  • Measuring method and device of pulse width detection type magnetic modulation direct current
  • Measuring method and device of pulse width detection type magnetic modulation direct current
  • Measuring method and device of pulse width detection type magnetic modulation direct current

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Embodiment 1

[0030] Embodiment 1 is a clamp-on ammeter for measuring direct current, and its magnetic modulation sensor includes a square wave generator 1, a coupling capacitor C, a resonant capacitor C1, a current sampling resistor R, a magnetic sensor 2, and a standard current source Is. Its magnetic sensor structure like image 3 As shown; the magnetic core FC is made of ferrite, which is divided into two symmetrical halves; the magnetic core is wound with an excitation coil N1 and a correction coil N2, and there is a magnetic shielding shell PO outside it, and the magnetic shielding shell is made of Permalloy The gap between the magnetic core and the magnetic shielding shell is filled with epoxy resin; the left and right halves can be opened and closed, and the central hole is used to clamp the measured wire. The square wave generator generates a voltage with a duty ratio of 1:1 , the frequency can be adjusted within the range of 1-10KHz, the signal generated by the square wave generat...

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PUM

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Abstract

The invention provides a measuring method and a device of pulse width detection type magnetic modulation direct current, comprising a magnetic modulation circuit, a magnetic sensor, a pulse width measuring and magnetic characteristic modifying circuit and a method, and the size and direction of the direct current to be measured are reflected through the variation of the pulse width of the pulse generated by measuring the magnetic modulation circuit. The working frequency of the adopted magnetic modulation signal is far higher than the power frequency, thus the interference of power frequency is avoided; the outside of the magnetic sensor is provided with a magnetic shielding case, which can effectively lower the influence of earth magnetic field and external interference magnetic field on the test, and magnetic characteristic modification measures are adopted. The method and device possess higher sensitivity, stronger capability of resisting interference, can effectively reduce the influence of magnetic material nonlinearity, and improve test precision and stability.

Description

technical field [0001] The invention relates to a method and device for measuring electrical parameters, in particular to a method and device for detecting weak and small direct currents. Background technique: [0002] The existing patent No. 98106874.X and its related technical paper "A New Magnetic Modulation DC Current Measurement Method" discloses a DC current detection method using a magnetic modulation circuit and phase difference detection technology to form a DC current measurement method. It utilizes: when the DC constant magnetic field exists, the symmetry of the alternating magnetic flux in the iron core will be destroyed, and the positive and negative half waves of the magnetic flux waveform will have relative phase shifts, and the magnitude and direction of the phase changes of the positive and negative half waves can reflect the DC bias. Set the characteristics of the magnitude and direction of the current to measure the current. The 25Hz triangular wave excit...

Claims

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Application Information

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IPC IPC(8): G01R19/00
Inventor 徐先
Owner 漳州市东南电子技术研究所有限公司
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