Abstract: According to one embodiment, there is provided a generator excitation apparatus including a plurality of first power converters and a second power converter. The plurality of first power converters are electrically connected to windings of respective phases of rotors of a wound rotor type induction generator in which the windings of the rotors of the respective phases are electrically independent, and are configured to bidirectionally convert DC and AC. The second power converter is configured to bidirectionally convert DC and AC between DC sides of the first power converters and a three-phase DC power supply. The DC sides of the first power converters are electrically connected together to a DC side of the second power converter.

Abstract: In one embodiment, an electric power converting device includes a converter which converts a three-phase AC voltage output from a three-phase AC power source, into a DC voltage of each phase of a three-phase AC load, and an inverter which converts the DC voltage converted by the converter, into a single-phase AC voltage of each phase of the three-phase AC load. The converter includes for each phase of an electric power system a circuit which consists of a plurality of switching elements connected in series. The electric power converting device controls on/off of a switching element corresponding to one of phases of the electric power system in the converter such that a voltage which reduces fluctuation of a DC voltage applied between the converter and the inverter and corresponding to each phase of the three-phase AC load is output from the converter for each phase of the electric power system.

Abstract: According to one embodiment, there is provided a generator excitation apparatus including a plurality of first power converters and a second power converter. The plurality of first power converters are electrically connected to windings of respective phases of rotors of a wound rotor type induction generator in which the windings of the rotors of the respective phases are electrically independent, and are configured to bidirectionally convert DC and AC. The second power converter is configured to bidirectionally convert DC and AC between DC sides of the first power converters and a three-phase DC power supply. The DC sides of the first power converters are electrically connected together to a DC side of the second power converter.

Abstract: A breaker 162 is opened when a pantograph 101 is lowered. The pantograph 101 is connected to an overhead wire 200. Voltage and its phase of the overhead wire are detected by a detector 161. Power is supplied from a power storage device 150c to a tertiary winding 112c via a power converter 14c such that a primary side of the main transformer 110 has the same voltage and phase as the overhead wire so as to reversely excite the main transformer 110. When the voltage of the main transformer 110 has the same phase as the voltage of the overhead wire 200, the breaker 162 is turned on and then the pantograph 101 is raised, to connect the overhead wire 200 and the main transformer 110 to each other, thereby preventing the occurrence of an excitation inrush current to the main transformer 110.

Abstract: In one embodiment, an electric power converting device includes a converter which converts a three-phase AC voltage output from a three-phase AC power source, into a DC voltage of each phase of a three-phase AC load, and an inverter which converts the DC voltage converted by the converter, into a single-phase AC voltage of each phase of the three-phase AC load. The converter includes for each phase of an electric power system a circuit which consists of a plurality of switching elements connected in series. The electric power converting device controls on/off of a switching element corresponding to one of phases of the electric power system in the converter such that a voltage which reduces fluctuation of a DC voltage applied between the converter and the inverter and corresponding to each phase of the three-phase AC load is output from the converter for each phase of the electric power system.

Abstract: A breaker 162 is opened when a pantograph 101 is lowered. The pantograph 101 is connected to an overhead wire 200. Voltage and its phase of the overhead wire are detected by a detector 161. Power is supplied from a power storage device 150c to a tertiary winding 112c via a power converter 14c such that a primary side of the main transformer 110 has the same voltage and phase as the overhead wire so as to reversely excite the main transformer 110. When the voltage of the main transformer 110 has the same phase as the voltage of the overhead wire 200, the breaker 162 is turned on and then the pantograph 101 is raised, to connect the overhead wire 200 and the main transformer 110 to each other, thereby preventing the occurrence of an excitation inrush current to the main transformer 110.