Isolated direct current converter applicable for medium-voltage direct current system and control method thereof

A DC converter and DC system technology, applied in the direction of converting DC power input to DC power output, control/regulation system, output power conversion device, etc., can solve the problem of high equipment reliability requirements, poor operating environment, and large power supply and other problems, to achieve the effect of fast and safe switching process, long service life and high overall reliability

CN109347327AInactive Publication Date: 2019-02-15HUNAN UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-02-15
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses an isolated direct current converter applicable for a medium-voltage direct current system and a control method thereof. The direct current converter is of a modularized combined structure for a plurality of power modules through serial connection during input and parallel connection during output, and each power module consists of a switching circuit and an isolated switching circuit cascade connection. Each switching circuit consists of a switching switch, a switching power device and a short circuit prevention diode, and is used for controlling the switching and elimination of the corresponding control module, so that redundant operation and rapid fault isolation of the system are realized; when an external fault appears, the fault can be quickly eliminated, andwhen an internal fault of the module appears, the fault module can be quickly eliminated, so that normal operation of the converter is guaranteed; simultaneously, input and output voltage matching ofeach module can be guaranteed, so that the stress of voltage and current on the power device is reduced; and after the fault is eliminated, the converter also can be quickly used. The converter disclosed by the invention is high in reliability and long in service life, and is applicable for the applications such as long-distance underwater electric energy supply, interconnection of direct currentmicrogrids with different voltage levels and electrolytic aluminum and sea water desalination industries.
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Description

technical field

[0001] The invention relates to a DC converter, in particular to a structure of a high-reliability isolated DC converter suitable for a medium-voltage DC power supply system and a control method thereof. Background technique

[0002] In the context of the transformation of the global energy landscape, DC power transmission and power distribution technology based on DC microgrids has become a solution to effectively utilize distributed renewable energy such as wind and light. Therefore, the interconnection between DC microgrids of different voltage levels is very important. ; On the other hand, traditional marine military, scientific research work and metal manufacturing industry and other energy supply places with special needs need adaptive power supply devices. The above application scenarios have the characteristics of high power supply, poor operating environment, and low maintainability. Therefore, the requirements for equipment reliability are high, and...

Examples

Embodiment Construction

[0018] see Figure 1 ~ Figure 3 .

[0019] The high-reliability isolated DC converter structure of the present invention, which is suitable for a medium-voltage DC power supply system, converts DC 10kV into DC+375V to realize the interconnection of DC buses of different voltage levels or supply loads.

[0020] High reliability isolated DC converter input series input inductance L 1 With the input terminals of 18 switching isolation power modules, a DC 10kV input is formed. Each switching isolation power module converts DC 625V to DC +375V, and the output terminals of each module are connected in parallel to form a DC+375V output terminal of the converter.

[0021] In this embodiment, the highly reliable isolated DC converter structure and its control method suitable for medium-voltage DC power supply systems have the following obvious advantages:

[0022] 1) The system has 10% to 20% redundant operation capability and high reliability. When a module fails, it can still conti...