A DC source based on current transformer resonance

Abstract

Disclosed in the invention is a current transformer resonance power taking-based direct-current source. The direct-current source comprises a current transformer, a resonant unit, a rectification unit and a control unit for controlling the rectification unit to adjust a direct-current output voltage of the rectification unit. According to the invention, a resonant capacitor is connected in parallel to an output terminal of the current transformer, so that excited inductance resonance is realized between the resonant capacitor and the current transformer in parallel connection. The electric energy obtained by induction is increased under the effect of the same high-voltage side currents; specially, when the high-voltage side current is low, the enough electric energy can be ensured to be obtained by the induction for providing for a load, thereby improving stability of an output power of the direct-current source. Meanwhile, because of improvement of the power taking efficiency of the transformer, the size of the direct-current source can be reduced to an optimal one, thereby effectively reducing the manufacturing cost of the transformer. In addition, a controllable rectifier bridge is used and thus the output voltage can be controlled according to a corresponding control strategy, thereby improving the service life of the transformer.

Description

technical field [0001] The invention belongs to the technical fields of current mutual inductance and power electronics, and in particular relates to a DC source based on current transformer resonance to obtain electricity. Background technique [0002] With the rapid development of urbanization, high-voltage cables have become the main components of the power grid, and online monitoring of their operating conditions has become an important link to improve the reliability of the power grid. In the cable operation monitoring system, the design of the power supply is one of the difficulties. For example, 220V AC mains power cannot be provided in underground wells or remote areas, and the use of photovoltaic panels for power supply is greatly affected by external weather. Only using transformers to directly obtain power from high-voltage cables is a more reliable power supply method. [0003] The Chinese patent No. 200910045470.9 discloses a power supply based on transformer i...

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Problems solved by technology

[0008] When the cable current is less than the starting current I 0 (min), the power cannot work

Under the condition that the number of turns of the secondary side remains unchanged, the traditional transformer power-taking circuit can only increase the excitation inductance, that is, increase the volume of the transformer magnetic core, so as to reduce the starting current to achieve the output voltage U s

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