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Direct-current-free magnetized bidirectional magnetic amplifier for direct-current large current detection

A magnetic amplifier, no DC technology, applied in the direction of measuring current/voltage, instruments, measuring devices, etc., can solve the problems of increasing the volume of the excitation transformer, reducing the efficiency, and failing to demagnetize, and achieving the effect of reducing the volume and improving the efficiency.

Inactive Publication Date: 2013-01-16
HUAZHONG UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the 1930s, W.Kraemer of Germany designed a magnetic amplifier for measuring large DC currents. The magnetic amplifier has two iron cores and a relatively simple structure, but it can only measure DC current flowing in one direction. One-way magnetic amplifiers, while those used in zero-flux DC high-current transformers or DC high-current comparators must be bidirectional magnetic amplifiers, which can measure DC currents in both positive and negative directions
However, because the DC pulsating current passes through the excitation transformer winding, it cannot be demagnetized, so there is a serious problem of DC magnetization, which leads to a large increase in the volume of the excitation transformer and a serious drop in efficiency.

Method used

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  • Direct-current-free magnetized bidirectional magnetic amplifier for direct-current large current detection
  • Direct-current-free magnetized bidirectional magnetic amplifier for direct-current large current detection
  • Direct-current-free magnetized bidirectional magnetic amplifier for direct-current large current detection

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example

[0034] The iron cores T1 and T2 of a bidirectional magnetic amplifier without DC magnetization are annular in shape, with a core diameter of 0.65m and a cross-sectional area of ​​0.7×10 -4 m 2 . The measured bus passes through the iron cores T1 and T2, so the turns of the primary coils W3 and W4 are equal to one turn, the turns of the secondary coils W5 and W6 are 1200 turns, and the turns of the exciting coils W1 and W2 are 1000 turns. The primary winding W7 of the excitation transformer B1 is connected to a single-phase AC power supply with a voltage of 220V and a frequency of 50Hz. The output voltage of the secondary winding W9 of the excitation transformer is 28V, and the output voltage of W8 is double 28V. The type of rectifier diodes D1-D2 is 2CZ57, the forward current is 5A, and the reverse voltage is 800V. Resistance R5=R6=10Ω.

[0035] The switch circuit is a thyristor switch circuit, which is composed of a thyristor SCR, a capacitor C, a voltage regulator tube Z ...

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Abstract

The invention belongs to the technical field of power measurement and particularly discloses a direct-current-free magnetized bidirectional magnetic amplifier for direct-current large current detection. The magnetic amplifier can be used for measuring bidirectional direct current by using two iron cores only. An excitation signal of the magnetic amplifier is provided by an excitation transformer and a switch circuit, and an excitation current flowing through a winding of the excitation transformer is an alternating current, so that the direct-current magnetizing phenomenon is inexistent in the excitation transformer, thereby improving the efficiency of the excitation transformer and reducing the volume. A synchronous control voltage of the switch circuit is directly obtained from a secondary winding of the excitation transformer. The magnetic amplifier can serve as a current sensor and is applied to a zero-magnetic-flux direct-current large current transformer and a direct-current large current comparator.

Description

technical field [0001] The invention belongs to the technical field of electric power measurement, and in particular relates to a direct current large current sensor, in particular to a bidirectional magnetic amplifier which is used as a sensor in high precision zero magnetic flux direct current large current measuring equipment and can measure direct current in both positive and negative directions. Background technique [0002] As the main high-precision DC high-current measurement equipment, zero-flux DC high-current transformers and DC high-current comparators are widely used in many fields such as cross-regional high-voltage DC transmission, non-ferrous metal smelting, electrochemistry, particle accelerators, etc. . [0003] The core component sensor in the zero-flux DC high-current transformer and the DC high-current comparator often uses a magnetic amplifier. When working, the magnetic amplifier plays two roles: first, compare the magnitude of the magnetic potential ...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R15/00
Inventor 徐垦徐雁肖霞
Owner HUAZHONG UNIV OF SCI & TECH
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