A turn-off dc converter and its multi-stage protection method and system

Abstract

The application discloses a turn-off DC converter and a multi-stage protection method and system thereof. The method comprises the following steps: setting an overvoltage breakdown diode for a power device in the turn-off DC converter; when the anode-cathode voltage of the power device exceeds the protection threshold of the overvoltage breakdown diode, the overvoltage breakdown diode is actively broken down to trigger the power device to open; connecting a metal oxide lightning arrester in parallel with the turn-off device module; the metal oxide lightning arrester performs overvoltage clamping protection on the turn-off device module; connecting a valve lightning arrester in parallel with the bridge arm; and the valve lightning arrester performs overvoltage protection on the bridge arm. The method can cope with overvoltage protection under various extreme working conditions and guarantee the safe operation of the power device, forming a multi-stage protection system. Through the protection design relationship, the protection effect of the converter valve can be gradually increased from inside to outside, and overvoltage protection can be performed on various extreme working conditions of the turn-off converter.

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