Bypass device and method of hvdc sub module

Patent metadata

Field	Value
Publication number	US-2022231594-A1
Application number	US-202117623133-A
Country	US
Kind code	A1
Filing date	May 11, 2021
Priority date	May 14, 2020
Publication date	Jul 21, 2022
Grant date	—

Abstract

A bypass device of an HVDC sub module according to the present invention comprises: a sub module for generating a voltage in an HVDC system; a bypass switch driving unit for driving a bypass switch located at an input terminal of the sub module; a sub module controller for monitoring a state of the sub module to transmit the monitored state to a system controller, and controlling the sub module and the bypass switch driving unit according to a command of the system controller; and a voltage monitoring unit for controlling the bypass switch driving unit by monitoring a voltage of a capacitor located in the sub module.

First claim

1 . A device for bypassing a high voltage direct current (HVDC) sub-module, the device comprising:
a sub-module configured to generate a voltage in an HVDC system; a bypass switch driving unit configured to drive a bypass switch positioned at an input of the sub-module; a sub-module controller configured to monitor a state of the sub-module to transmit the monitored state to a system controller and control the sub-module and the bypass switch driving unit according to a command of the system controller; and a voltage monitoring unit configured to monitor a voltage of a capacitor positioned in the sub-module and control the bypass switch driving unit.

2 . The device of claim 1 , wherein the sub-module includes:
the capacitor configured to store and release energy; an insulated gate bipolar transistor1 (IGBT1) and a first diode which are positioned between a P input of the sub-module and a positive terminal of the capacitor; and an insulated gate bipolar transistor2 (IGBT2) and a second diode which are positioned between the P input and a negative terminal of the capacitor connected to an N input of the sub-module.

3 . The device of claim 1 , wherein the bypass switch is connected between a P input and an N input of the sub-module and bypasses the P input and the N input under control of the bypass switch driving unit.

4 . The device of claim 1 , wherein the sub-module controller controls both the IGBT1 and the IGBT2 to be turned off to allow input energy of the sub-module to be stored in the capacitor through the first diode in a section in which a P input voltage of the sub-module is higher than an N input voltage thereof.

5 . The device of claim 1 , wherein the sub-module controller controls the IGBT1 to be turned on and controls the IGBT2 to be turned off to allow energy charged in the capacitor to be released to an input of the sub-module in a section in which a P input voltage of the sub-module is lower than an N input voltage thereof.

6 . The device of claim 1 , wherein the sub-module controller controls the IGBT1 to be turned off and controls the IGBT2 to be turned on to bypass the P input and the N input of the sub-module.

7 . The device of claim 1 , wherein, when the voltage of the capacitor exceeds a bypass switch-on voltage by the sub-module controller positioned between an operating voltage and a capacitor limit voltage, the sub-module controller controls the bypass switch driving unit to perform bypass at the input of the sub-module.

8 . The device of claim 7 , wherein, when the voltage of the capacitor exceeds a bypass switch-on voltage by the voltage monitoring unit positioned between the bypass switch-on voltage by the sub-module controller and the capacitor limit voltage, the voltage monitoring unit controls the bypass switch driving unit to perform bypass at the input of the sub-module.

9 . A method of bypassing a high voltage direct current (HVDC) sub-module, the method comprising:
a system controller command receiving operation of receiving, by a sub-module controller, a control command from a system controller; an energy storage operation of, when the control command indicates energy storage, controlling, by the sub-module controller, an insulated gate bipolar transistor1 (IGBT1) and an insulated gate bipolar transistor2 (IGBT2) of a sub-module to construct a path through which energy is storable in a capacitor in the sub-module; an energy release operation of, when the control command indicates energy release, controlling, by the sub-module controller, the IGBT1 and the IGBT2 of the sub-module to construct a path through which energy of the capacitor in the sub-module is releasable; a bypass operation of, when the control command indicates bypass, controlling, by the sub-module controller, the IGBT1 and the IGBT2 of the sub-module to block a path with the capacitor in the sub-module and construct a bypass path; a capacitor voltage transmitting operation of, when it is checked whether a voltage of the capacitor in the sub-module is greater than a bypass switch-on voltage by the sub-module controller and the voltage of the capacitor is less than the bypass switch-on voltage (V 830 ) by the sub-module controller, transmitting the voltage of the capacitor to the system controller; a bypass switch driving unit turning-on operation of, when the voltage of the capacitor in the sub-module is greater than the bypass switch-on voltage by the sub-module controller, comparing the voltage of the capacitor in the sub-module with a bypass switch-on voltage by a voltage monitoring unit and, when the voltage of the capacitor is greater than the bypass switch-on voltage by the voltage monitoring unit, turning a bypass switch driving unit on; and a bypass switch turning-on operation of turning, by the bypass switch driving unit, a bypass switch on.

10 . The method of claim 9 , wherein, in the energy storage operation, the sub-module controller controls both the IGBT1 and the IGBT2 to be turned off to allow input energy of the sub-module to be stored in the capacitor through a first diode in a section in which a P input voltage of the sub-module is higher than an N input voltage thereof.

11 . The method of claim 9 , wherein, in the energy release operation, the sub-module controller controls the IGBT1 to be turned on and controls the IGBT2 to be turned off to allow energy charged in the capacitor to be released to an input of the sub-module in a section in which a P input voltage of the sub-module is lower than an N input voltage thereof.

12 . The method of claim 9 , wherein, in the bypass operation, the sub-module controller controls the IGBT1 to be turned off and controls the IGBT2 to be turned on to bypass a P input and an N input of the sub-module.

13 . The method of claim 9 , wherein the bypass switch-on voltage by the voltage monitoring unit is positioned between the bypass switch-on voltage by the sub-module controller and the capacitor limit voltage.

Assignees

• Hyosung Heavy Ind Corp

Inventors

• Hong Jung Ki
• Seo Dong Woo

Classifications

• Y02E60/60

  Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD] · CPC title

• H02M7/4835

  comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage · CPC title

• H02M1/325

  with means for allowing continuous operation despite a fault, i.e. fault tolerant converters · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• Y02E40/10

  Flexible AC transmission systems [FACTS] · CPC title