Self-blocking sub-module with energy-consuming resistor and application thereof

Abstract

The invention discloses a self-blocking sub-module topological structure with an energy-consuming resistor. The sub-module topological structure comprises two switch modules connected in series, a DC capacitor, a third switch module, a diode, and the energy-consuming resistor. Each of the two switch modules is composed of a full-controlled device and a diode in inverse parallel connection. The negative end of the first switch module is connected with the positive end of the second switch module. The positive pole and the negative pole of the DC capacitor are connected with the positive end of the first switch module and the negative end of the second switch module respectively. The third switch module is electrically connected with the first switch module or the second switch module. The diode is electrically connected with the third switch module and the DC capacitor. The energy-consuming resistor and the diode are connected in series to form a series connection assembly. The invention further discloses a modular multi-level converter containing the self-blocking sub-module topological structure. The self-blocking sub-module topological structure may inhibit an increase in the voltage of a sub-module DC capacitor for the duration of blocking a DC fault, and guarantees system operation safety.

Description

technical field [0001] The invention belongs to the technical field of electric power transmission and distribution, and more specifically relates to a self-resistance sub-module topology and a hybrid converter with the self-resistance sub-module topology. Background technique [0002] Self-blocking sub-module (Self-blocking Sub-module) is a new type of modular multilevel converter sub-module topology, the modular multilevel converter (MMC) composed of it has the ability to block DC fault current Function, suitable for overhead line DC transmission occasions. [0003] Currently recognized modular multilevel converter sub-modules include half-bridge sub-modules, full-bridge sub-modules and clamped double-type sub-modules. The MMC composed of half-bridge sub-modules does not have the ability to block the DC fault current. When a DC fault occurs, it is necessary to open the AC circuit breaker or rely on the DC circuit breaker to cut off the DC fault path. This method reduces t...

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Problems solved by technology

But before the fault current drops to zero, the fault current flows through D1, C, and D4, and continues to charge the DC capacitor C, causing the voltage of the DC capacitor to rise

[0005] When the self-resistance type sub-module is used for intermediate frequency MMC (such as 200Hz-500Hz MMC), since the capacitance of the intermediate frequency MMC sub-module and the inductance of the bridge arm are small, the charging of the DC capacitor voltage will cause the voltage of the DC capacitor to rise quickly. When the value is high, the full-control device of the sub-module will be subjected to high voltage, which may damage the full-control device, thereby threatening the safe operation of the system. Therefore, certain measures must be taken to suppress the rise of the DC capacitor voltage

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