Abstract: The present invention relates to a first-cycle charging device and method of a modular multi-level converter, in which, in order to prevent the overcharging of a capacitor in a submodule in a HVDC system, charging and discharging of the capacitor in the submodule are independently carried out, and charging of the submodule in the HVDC system is enabled to be gradually carried out so as to prevent sudden flow of an instantaneous current. The first-cycle charging device of the modular multi-level converter of the present invention comprises: a submodule provided with a capacitor so as to carry out alternating current power charging and discharging; and a submodule control unit for controlling the charging, discharging, and bypassing of the submodule.

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: A method includes receiving a voice input at an electronic device. An ambiguity of the voice input is determined. The ambiguity is resolved based on contextual data. The contextual data includes at least one of: an image, a non-voice input comprising a gesture, a pointer of a pointing device, a touch, or a combination thereof.

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: 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: A power supply for a submodule controller of an MMC converter, which supplies driving power to a submodule controller of an MMC connected to an HVDC system. The power supply includes: a bridge circuit unit including an energy storage unit storing a DC voltage of a series-connected submodule of the MMC converter, and multiple power semiconductor devices connected in parallel to the energy storage unit in a bridge form; a first resistor unit connected in parallel to the energy storage unit, and configured with at least one series-connected resistor; a second resistor unit connected in series to the first resistor unit; a switch unit connected in parallel to the first resistor unit; and a DC/DC converter converting a voltage output from output terminals formed in both ends of the second resistor unit into a low voltage, and supplying the same to the submodule controller.

Abstract: The present invention provides a method of MMC for HVDC. According to the present invention, there is provided a redundancy control method of an MMC for HVDC, wherein the MMC includes multiple converter arms each has multiple submodules in operation and redundancy modules for spares, the method including: checking whether a breakdown of a submodule in operation of a first converter arm among the multiple converter arms occurs in a case where the all redundancy modules of the first converter arm are applied in operation; and lowering an output voltage of each submodule of other converter arms in such a manner that a DC link voltage of each of the other converter arms is controlled to be equal to a DC link voltage of the first converter arm when the breakdown of the submodule of the first converter arm occurs.

Abstract: The present invention provides a method of MMC for HVDC. According to the present invention, there is provided a redundancy control method of an MMC for HVDC, wherein the MMC includes multiple converter arms each has multiple submodules in operation and redundancy modules for spares, the method including: checking whether a breakdown of a submodule in operation of a first converter arm among the multiple converter arms occurs in a case where the all redundancy modules of the first converter arm are applied in operation; and lowering an output voltage of each submodule of other converter arms in such a manner that a DC link voltage of each of the other converter arms is controlled to be equal to a DC link voltage of the first converter arm when the breakdown of the submodule of the first converter arm occurs.

Abstract: A method includes receiving a voice input at an electronic device. An ambiguity of the voice input is determined. The ambiguity is resolved based on contextual data. The contextual data includes at least one of: an image, a non-voice input comprising a gesture, a pointer of a pointing device, a touch, or a combination thereof.