Abstract: Proposed is a sub-module of a power converter, the sub-module capable of allowing failure-causing electric current to quickly bypass the sub-module when a failure occurs in the sub-module. A sub-module of a power converter according to an embodiment of the present disclosure, the sub-module including an energy storage unit, at least one power semiconductor circuit connected, in parallel, to the energy storage unit and configured with a plurality of power semiconductor switches and a plurality of freewheeling diodes, and a switching element arranged between two output terminals connected to one of one or more of the power semiconductor circuits, forced to undergo an induced failure when an induced-failure signal is input into a gate terminal thereof, and internally short-circuited, thereby connecting the output terminals to each other.

Abstract: Proposed is a submodule of an MMC converter configured to stably supply power to a submodule controller controlling the submodule of an MMC converter. The submodule includes: an energy storage part storing electric energy therein; a plurality of switching elements connected in parallel to the energy storage part to have a shape of a bridge; a plurality of serially-connected resistors connected in parallel to the energy storage part; a plurality of DC-DC converters connected in parallel to a resistor of the plurality of resistors; a power switching part operating to select and output one voltage of voltages output from the plurality of DC-DC converters and a plurality of voltages input from outside; and a submodule controller operating with the voltage output by the power switching part so as to control switching operations of the plurality of switching elements.

Abstract: A component grounding system according to one embodiment includes a case for accommodating a plurality of components, a direct current (DC) capacitor disposed on one side of the case and electrically connected to the case, and a bus bar, disposed between the case and the DC capacitor, for connecting the case and the DC capacitor, the bus bar representing an electrode, wherein each of the plurality of components may be connected to the bus bar.

Abstract: Provided are a graphene-based fiber in which a liquid-crystalline aromatic compound is intercalated into a graphene-based material, a graphene-based carbon fiber obtained by carbonizing the graphene-based fiber, and a method of manufacturing the same.

Abstract: The present disclosure relates to a sub-module of a power converter, the sub-module capable of allowing failure-causing electric current to bypass the sub-module when a failure occurs in the sub-module.

Abstract: Proposed is a sub-module of a power converter, the sub-module capable of allowing failure-causing electric current to quickly bypass the sub-module when a failure occurs in the sub-module. A sub-module of a power converter according to an embodiment of the present disclosure, the sub-module including an energy storage unit, at least one power semiconductor circuit connected, in parallel, to the energy storage unit and configured with a plurality of power semiconductor switches and a plurality of freewheeling diodes, and a switching element arranged between two output terminals connected to one of one or more of the power semiconductor circuits, forced to undergo an induced failure when an induced-failure signal is input into a gate terminal thereof, and internally short-circuited, thereby connecting the output terminals to each other.

Abstract: The present disclosure relates to a sub-module of a power converter, the sub-module capable of allowing failure-causing electric current to bypass the sub-module when a failure occurs in the sub-module.

Abstract: A method for diagnosing a state of a submodule in initial charging of an MMC converter includes identifying, by an upper level controller, a stopped state of the MMC converter; supplying, by the upper level controller, an alternating current (AC) voltage from an AC side to N submodules in the MMC converter when the MMC converter is in the stopped state; charging a capacitor in the submodule with the supplied AC voltage to store an initial charging voltage in the capacitor; determining, by a submodule controller, whether the submodule is in a fault state and when the submodule is in a fault state, transmitting a fault signal to the upper level controller; and detecting, by a voltage detection unit of the submodule the initial charging voltage stored in the capacitor and transmitting the initial charging voltage to the submodule controller.

Abstract: Proposed is a submodule of an MMC converter configured to stably supply power to a submodule controller controlling the submodule of an MMC converter. The submodule includes: an energy storage part storing electric energy therein; a plurality of switching elements connected in parallel to the energy storage part to have a shape of a bridge; a plurality of serially-connected resistors connected in parallel to the energy storage part; a plurality of DC-DC converters connected in parallel to a resistor of the plurality of resistors; a power switching part operating to select and output one voltage of voltages output from the plurality of DC-DC converters and a plurality of voltages input from outside; and a submodule controller operating with the voltage output by the power switching part so as to control switching operations of the plurality of switching elements.

Abstract: Provided is a 2D nanomaterial fiber. The 2D nanomaterial fiber includes plate-type fibrous cross sections formed by orienting a 2D nanomaterial in a longitudinal direction and stacking the oriented 2D nanomaterial.

Abstract: An MMC converter linked to a HVDC system and a sub-module constituting the MMC converter are proposed. The sub-module includes: first and second power semiconductor switches connected in series in the same direction, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; a capacitor connected in parallel to the first and second power semiconductor switches connected together in series; a first terminal connected to a first node between the first and second power semiconductor switches; a second terminal connected to a second node between the second power semiconductor switch and the capacitor; third and fourth power semiconductor switches connected in series in opposite directions between the first and second terminals, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; and a third terminal connected to a third node between the third and fourth power semiconductor switches.

Abstract: A method for diagnosing a state of a submodule in initial charging of an MMC converter includes identifying, by an upper level controller, a stopped state of the MMC converter; supplying, by the upper level controller, an alternating current (AC) voltage from an AC side to N submodules in the MMC converter when the MMC converter is in the stopped state; charging a capacitor in the submodule with the supplied AC voltage to store an initial charging voltage in the capacitor; determining, by a submodule controller, whether the submodule is in a fault state and when the submodule is in a fault state, transmitting a fault signal to the upper level controller; and detecting, by a voltage detection unit of the submodule the initial charging voltage stored in the capacitor and transmitting the initial charging voltage to the submodule controller.

Abstract: An MMC converter linked to a HVDC system and a sub-module constituting the MMC converter are proposed. The sub-module includes: first and second power semiconductor switches connected in series in the same direction, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; a capacitor connected in parallel to the first and second power semiconductor switches connected together in series; a first terminal connected to a first node between the first and second power semiconductor switches; a second terminal connected to a second node between the second power semiconductor switch and the capacitor; third and fourth power semiconductor switches connected in series in opposite directions between the first and second terminals, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; and a third terminal connected to a third node between the third and fourth power semiconductor switches.

Abstract: An MMC converter linked to a HVDC system and a sub-module are proposed. The sub-module includes: first and second power semiconductor switches serially connected in the same direction, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; a capacitor parallelly connected to the first and second power semiconductor switches serially connected; a first terminal connected to a first node between the first and second power semiconductor switches; a second terminal connected to a second node between the second power semiconductor switch and the capacitor; a third power semiconductor switch of which a side is connected to the second node, the third power semiconductor switch including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; and a third terminal connected to a terminal of an AC grid system and connected to the other side of the third power semiconductor switch.

Abstract: The present invention relates to a liquid crystal composite elastic fiber manufactured by means of spinning a graphene-based composition in which graphene-based materials are dispersed into a polymer solution including polymer having a polar group so that the polymer is intercalated in or chemically reacted with the graphene-based materials. The present invention also related to a method of manufacturing the same.

Abstract: Provided is a hybrid control device for a static synchronous compensator (STATCOM), the device including: a first arithmetic operation unit calculating the deviation between a reference voltage desired to be controlled by the STATCOM and output voltage to be output so as to output the same; a proportional integral (PI) controller performing PI control on the deviation output from the first arithmetic operation unit within a range between a new inductive reactive current maximum value and a new capacitive reactive current maximum value, so as to output a reactive current output value; and a second arithmetic operation unit adding the preset reactive current set value to the reactive current output value output from the PI control unit so as to output a reactive current reference value.

Abstract: Proposed is a power supply device for a submodule controller of a modular multilevel converter (MMC) connected to a high voltage direct current (HVDC) system, which generates and supplies power through by hydraulic turbine generation using coolant flowing through a heat sink that cools a submodule. The power supply device includes a heat sink disposed inside the submodule of the MMC converter to cool the submodule using coolant; a pipe having an inlet configured to supply the coolant to the heat sink and an outlet configured to discharge the coolant to outside of the heat sink and configured to form a flow path to cause the coolant supplied through the inlet to flow to the heat sink; and a hydraulic turbine generator disposed at one side of the pipe to generate power by the coolant flowing through the pipe and supply the power to the submodule controller.

Abstract: Provided is a hybrid control device for a static synchronous compensator (STATCOM), the device including: a first arithmetic operation unit calculating the deviation between a reference voltage desired to be controlled by the STATCOM and output voltage to be output so as to output the same; a proportional integral (PI) controller performing PI control on the deviation output from the first arithmetic operation unit within a range between a new inductive reactive current maximum value and a new capacitive reactive current maximum value, so as to output a reactive current output value; and a second arithmetic operation unit adding the preset reactive current set value to the reactive current output value output from the PI control unit so as to output a reactive current reference value.

Abstract: An MMC converter linked to a HVDC system and a sub-module are proposed. The sub-module includes: first and second power semiconductor switches serially connected in the same direction, each including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; a capacitor parallelly connected to the first and second power semiconductor switches serially connected; a first terminal connected to a first node between the first and second power semiconductor switches; a second terminal connected to a second node between the second power semiconductor switch and the capacitor; a third power semiconductor switch of which a side is connected to the second node, the third power semiconductor switch including a semiconductor switch and a diode connected in anti-parallel to the semiconductor switch; and a third terminal connected to a terminal of an AC grid system and connected to the other side of the third power semiconductor switch.

Abstract: Provided are a graphene-based fiber in which a liquid-crystalline aromatic compound is intercalated into a graphene-based material, a graphene-based carbon fiber obtained by carbonizing the graphene-based fiber, and a method of manufacturing the same.