Zero-flux current transformer and error modulation method

A current transformer, zero-flux technology, applied in the direction of only measuring current, voltage/current isolation, measuring current/voltage, etc., can solve the problem that the current transformer error cannot be theoretically eliminated, and achieves low material and cross-section. , the effect of reducing weight and volume, and improving measurement accuracy

Inactive Publication Date: 2021-02-26
WUHAN UNIV
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  • Application Information

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Problems solved by technology

However, the excitation current still exists, and the error of the current transformer cannot be eliminated theoretically. Therefore, scholars have proposed various methods of compensating the current transformer around eliminating the error caused by the excitation current of the current transformer. The excitation current in the transformer is zero, and the magnetic core is in the state of "zero flux"

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  • Zero-flux current transformer and error modulation method
  • Zero-flux current transformer and error modulation method

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Embodiment Construction

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] see figure 1 , the embodiment of the present invention includes a ring magnetic core, two coils surrounding the magnetic core, a sampling unit and a controllable current source, a main control unit and a display unit.

[0027] The cross-section of the ring core is a rectangular ring core, which can be made into an open-loop or closed-loop form, but it is recommended to choose a closed-loop form to eliminate the influence of the air gap of the core and improve the measurement accuracy of the sensor. The material of the ring magnetic core is selected as a material with high magnetic permeability, such as ferrite. The cross-section of the annular magnetic core should be as large as possible while considering the weight of the device, so as to improve the electromagnetic conversion sensitivity and accuracy of the transformer devic...

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Abstract

The invention provides a zero-flux current transformer and an error modulation method. The zero-flux current transformer comprises an annular magnetic core, a primary side coil N1, a sampling coil N3,a secondary side coil N2, a sampling unit, a controllable current source and a main control unit; based on an error modulation principle, a current accumulation error is eliminated by compensating anexciting current, so that the magnetic core is in a zero-flux state, the magnetic error of the current transformer is zero, and a measurement result has relatively high precision. Only one magnetic core is needed, the requirements for the material and the cross section of the magnetic core are low, and the weight and the size of the transformer are reduced.

Description

technical field [0001] The invention belongs to the technical field of current transformers, and in particular relates to a zero-flux current transformer and an error modulation method. Background technique [0002] As the first-level sampling unit, the current sensor is widely used in on-line monitoring devices for electrical equipment insulation. According to different measurement principles, current sensors can be mainly divided into: shunts, electromagnetic current transformers, photoelectric current transformers, etc. The shunt needs to be directly connected in series with the grounding wire of electrical equipment, which poses safety hazards to electrical equipment, power systems and staff; photoelectric current transformers measure weak leakage currents in power systems with strong electromagnetic interference, with poor linearity and poor accuracy. Low, immature technology. Therefore, electromagnetic current transformers are mainly used in power systems at present....

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): G01R15/18G01R19/00
CPCG01R15/185G01R19/0092
Inventor黄宗武乔雪峰袁佳歆
OwnerWUHAN UNIV