Abstract: According to one embodiment, a control system includes a chopper, a short-circuit unit, a voltage detector circuit, and a controller. The chopper reduces a direct current voltage between a converter connected to a stator in a wound induction machine and an inverter connected to a rotor in the wound induction machine. The short-circuit unit shorts a wire used for connection between the rotor and the inverter and the voltage detector circuit is to detect the direct current voltage. The controller causes driving the chopper and, at the same time, outputting from the inverter an alternating current over which a direct current component is superimposed when a voltage value exceeds a first predetermined value, and causes driving the short-circuit unit and, at the same time, halting the inverter when the voltage value exceeds a second predetermined value.

Abstract: According to one embodiment, a control system includes a chopper, a short-circuit unit, a voltage detector circuit, and a controller. The chopper reduces a direct current voltage between a converter connected to a stator in a wound induction machine and an inverter connected to a rotor in the wound induction machine. The short-circuit unit shorts a wire used for connection between the rotor and the inverter and the voltage detector circuit is to detect the direct current voltage. The controller causes driving the chopper and, at the same time, outputting from the inverter an alternating current over which a direct current component is superimposed when a voltage value exceeds a first predetermined value, and causes driving the short-circuit unit and, at the same time, halting the inverter when the voltage value exceeds a second predetermined value.

Abstract: In a power converter a DC positive terminal of a DC power supply is connected to a switching element, the DC negative terminal of the DC power supply is connected to a switching element. A capacitor and a capacitor connected in series are connected in parallel with the DC power supply, and a DC neutral point divided by the capacitor and the capacitor is connected to a switching element and a switching element. The switching element is connected to the positive terminal of a chopper cell group circuit, and the switching element is connected to the negative terminal of a chopper cell group circuit. The negative terminal of the chopper cell group circuit is connected to the positive terminal of the chopper cell group circuit, and the connection node therebetween serves as an output AC terminal.

Abstract: According to one embodiment, there is provided a power conversion device, including a control unit configured to control ON/OFF of a switching element of a neutral-point-clamped power conversion device unit, wherein the control unit drives the power conversion device unit by a one-pulse control, controls a phase difference of an output voltage of the power conversion device unit with respect to a reference phase of to control an active current component of an output current of the power conversion device unit, and controls ON/OFF based on: (a) a phase angle for eliminating a predetermined odd-order harmonic component of the output voltage; and (b) a sum of the reference phase and the phase difference.

Abstract: According to one embodiment, there is provided a control device of a neutral-point-clamped power converter apparatus including a converter configured to convert current which were obtained by passing a d-axis current and a q-axis current of a rotating coordinate system through a filter having a time constant which is greater than an inverse number of a fundamental wave frequency of a three-phase currents, to three-phase currents, and a controller configured to calculate, based on the three-phase currents converted, a zero-phase voltage instruction value for controlling voltages into which a DC input voltage is divided at a neutral point, as an instruction value which is superimposed on three-phase voltage instruction values.

Abstract: According to one embodiment, there is provided a switching element driving power supply circuit that converts a main circuit voltage into a driving voltage of power-converting switching elements. The circuit includes a plurality of insulating power supplies, and a plurality of switching element driving power supply units. The insulating power supplies have respective direct-current input circuit ends connected in series, respective input-side circuits and output-side circuits insulated from each other, and respective output circuit ends connected in parallel. The power supply units are connected in parallel with the output circuit ends, and supplying power to the gate driving circuits of the power conversion switching elements.

Abstract: According to an embodiment, a power conversion apparatus for a vehicle is provided with a single-phase two-level converter and a single-phase three-level converter. The single-phase two-level converter is composed of a capacitor, first to fourth controllable switching devices, diodes connected in antiparallel with the controllable switching devices, respectively. The single-phase three-level converter is composed of two series-connected capacitors, fifth to tenth controllable switching devices, diodes connected in antiparallel with the controllable switching devices, respectively. The single-phase two-level converter and the single-phase three-phase converter are connected in series at the AC input/output points. The single-phase two-level converter has smaller switching loss than the single-phase three-level converter, and the single-phase three-level converter has higher withstand voltage property than the single-phase two-level converter.

Abstract: According to one embodiment, an over-voltage prevention device includes a first short-circuit device provided between a secondary side of a wound-rotor induction machine and a frequency converter configured to excite the secondary side by a three-phase AC current and having a function of short-circuiting between phases of the three-phase AC current, resistors each connected between the first short-circuit device and the frequency converter for each phase, and second short-circuit devices connected respectively to the resistors in parallel and having a function of short-circuiting between the frequency converter and the secondary side of the wound-rotor induction machine.

Abstract: In a power converter a DC positive terminal of a DC power supply is connected to a switching element, the DC negative terminal of the DC power supply is connected to a switching element. A capacitor and a capacitor connected in series are connected in parallel with the DC power supply, and a DC neutral point divided by the capacitor and the capacitor is connected to a switching element and a switching element. The switching element is connected to the positive terminal of a chopper cell group circuit, and the switching element is connected to the negative terminal of a chopper cell group circuit. The negative terminal of the chopper cell group circuit is connected to the positive terminal of the chopper cell group circuit, and the connection node therebetween serves as an output AC terminal.

Abstract: A power conversion apparatus comprises a first converter connected to a second converter. The first converter includes a first capacitor and the second converter includes a second capacitor connected in series to a third capacitor. The capacitors are each connected in parallel with a respective resistor. The power conversion apparatus also includes a bypass switch connected in parallel to the first converter and in series to the second converter. A control module is configured to control a single-phase output voltage by operation of the first converter, the second converter, and the bypass switch.

Abstract: According to one embodiment, there is provided a power conversion device, including a control unit configured to control ON/OFF of a switching element of a neutral-point-clamped power conversion device unit, wherein the control unit drives the power conversion device unit by a one-pulse control, controls a phase difference of an output voltage of the power conversion device unit with respect to a reference phase of to control an active current component of an output current of the power conversion device unit, and controls ON/OFF based on: (a) a phase angle for eliminating a predetermined odd-order harmonic component of the output voltage; and (b) a sum of the reference phase and the phase difference.

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: According to one embodiment, there is provided a switching element driving power supply circuit that converts a main circuit voltage into a driving voltage of power-converting switching elements. The circuit includes a plurality of insulating power supplies, and a plurality of switching element driving power supply units. The insulating power supplies have respective direct-current input circuit ends connected in series, respective input-side circuits and output-side circuits insulated from each other, and respective output circuit ends connected in parallel. The power supply units are connected in parallel with the output circuit ends, and supplying power to the gate driving circuits of the power conversion switching elements.

Abstract: According to one embodiment, there is provided a control device of a neutral-point-clamped power converter apparatus including a converter configured to convert current which were obtained by passing a d-axis current and a q-axis current of a rotating coordinate system through a filter having a time constant which is greater than an inverse number of a fundamental wave frequency of a three-phase currents, to three-phase currents, and a controller configured to calculate, based on the three-phase currents converted, a zero-phase voltage instruction value for controlling voltages into which a DC input voltage is divided at a neutral point, as an instruction value which is superimposed on three-phase voltage instruction values.

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, an over-voltage prevention device includes a first short-circuit device provided between a secondary side of a wound-rotor induction machine and a frequency converter configured to excite the secondary side by a three-phase AC current and having a function of short-circuiting between phases of the three-phase AC current, resistors each connected between the first short-circuit device and the frequency converter for each phase, and second short-circuit devices connected respectively to the resistors in parallel and having a function of short-circuiting between the frequency converter and the secondary side of the wound-rotor induction machine.

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: According to an embodiment, a power conversion apparatus for a vehicle is provided with a single-phase two-level converter and a single-phase three-level converter. The single-phase two-level converter is composed of a capacitor, first to fourth controllable switching devices, diodes connected in antiparallel with the controllable switching devices, respectively. The single-phase three-level converter is composed of two series-connected capacitors, fifth to tenth controllable switching devices, diodes connected in antiparallel with the controllable switching devices, respectively. The single-phase two-level converter and the single-phase three-phase converter are connected in series at the AC input/output points. The single-phase two-level converter has smaller switching loss than the single-phase three-level converter, and the single-phase three-level converter has higher withstand voltage property than the single-phase two-level converter.

Abstract: A power conversion apparatus comprises a first converter connected to a second converter. The first converter includes a first capacitor and the second converter includes a second capacitor connected in series to a third capacitor. The capacitors are each connected in parallel with a respective resistor. The power conversion apparatus also includes a bypass switch connected in parallel to the first converter and in series to the second converter. A control module is configured to control a single-phase output voltage by operation of the first converter, the second converter, and the bypass switch.

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.