Abstract: An acoustic device includes a rotary operator and a base supporting the rotary operator so that the rotary operator is rotatable. The base includes a braking unit configured to be brought into contact with the rotary operator to cause a braking force to act on the rotary operator and an adjuster configured to adjust the braking force caused by the braking unit. The braking unit includes a plurality of contact members configured to be brought into contact with the rotary operator to cause the braking force to act on the rotary operator. The braking force acting on the rotary operator by the plurality of the contact members varies depending on an adjustment amount by the adjuster.

Abstract: Provided are a sub inverter of a full-bridge constituted by two arms: an arm and an arm, each of which is mounted on a different module, a main controller to drive and control the sub inverter by switching an operation mode between a first mode in which a first arm performs a low-frequency switching operation and a second arm performs a high-frequency switching operation, and a second mode in which the second arm performs a low-frequency switching operation and the first arm performs a high-frequency switching operation, and an operation ratio setting circuitry to set an operation ratio on the basis of a bias of a temperature rise between the modules.

Abstract: A three-phase multilevel inverter is connected to a first direct-current voltage source having a first voltage. Single-phase inverters are each connected in series to a corresponding phase of the three-phase multilevel inverter, and include a second direct-current voltage source, respectively, each having a second voltage. Combined output voltages, which are combinations of boost voltages generated by the three single-phase inverters and output voltages of the three-phase multilevel inverter, are supplied to a load. The control device adjusts a common mode voltage of the combined output voltages to be within a predetermined allowable range, and variation ranges of the line voltages in the combined output voltages to satisfy a specified condition established with the second voltage as a reference.

Abstract: For connected-in-parallel N DC-DC converters (1 to N, where N is 3 or more), a first converter group on which PWM switching is performed with a first carrier, and a second converter group on which PWM switching is performed with a second carrier having a phase different from that of the first carrier, are provided. One or more of the DC-DC converters (1 to N) are assigned to each converter group. A plurality of drive modes in which the number of the DC-DC converters that are driven and the converter groups are set, are provided. The drive modes are switched through comparison between a preset threshold value and a total output of the N DC-DC converters (1 to N), and a ratio between total outputs in the first and second converter groups is set to fall within a predetermined range.

Abstract: A power converter includes an inverter circuit connected between the positive and negative terminals of a DC power supply, three single-phase bridge circuits each connected in series between an AC terminal of one of different phases of the inverter circuit and a motor, and a power conversion controller that generates gate signals to control operations of the inverter circuit and the three single-phase bridge circuits based on phase voltage commands. When a semiconductor switching element of the single-phase bridge circuits fails, the power conversion controller sets the output voltage of the single-phase bridge circuit of a phase to which the faulty semiconductor switching element belongs to zero to continue operation.

Abstract: A method of preheating an unfinished stator as an intermediate product before a stator as a final product for a motor is provided in order to preheat a mold for molding together with the unfinished stator in short time by using preheating facilities with simplified structures. In the method, the mold has a hollow and longitudinal barrel portion and a flange portion extending outward from an end of the barrel portion. The flange portion is arranged at a horizontal position to turn the barrel portion upward and an end of a cylindrical and longitudinal frame is put on the flange portion in a state where a core of the unfinished stator is fitted in the frame. A heat-resistant box of which an underside is opened covers the frame and the mold to surrounded outsides of the frame and the mold.

Abstract: A power conversion apparatus includes a hermetic housing, a power semiconductor module, and dry gas. The hermetic housing includes a gas inlet valve and a gas outlet valve. The power semiconductor module is arranged in an internal space in the hermetic housing. The internal space in the hermetic housing is filled with dry gas.

Abstract: Provided is a gradationally controlled inverter formed by series-connection between: a main inverter circuitry which has main inverter arms for outputting AC voltages for respective phases, and to which a voltage of a DC source is applied through a DC busbar; and a sub-inverter circuitry having three single-phase sub-inverters. Each of short-circuit switches is connected between an input terminal and an output terminal of a corresponding one of the sub-inverters. At the time of a failure of the sub-inverter, a bypass for current is formed for only the failure phase by causing short-circuiting at the short-circuit switch connected to the sub-inverter, and only the main inverter arm for the failure phase is operated as a three-level inverter.

Abstract: A power conversion device is provided between a power supply and a load, and converts power from the power supply and supplies the converted power to the load. The power conversion device includes a plurality of switching elements composed of semiconductor elements, and a control device which generates drive signals for controlling the plurality of switching elements. Voltages are respectively applied to the plurality of semiconductor elements, on the basis of the drive signals generated by the control device. The plurality of semiconductor elements have equivalent failure probabilities due to neutron beams. Thus, a failure of the power conversion device due to neutron beams is prevented, and size increase thereof is suppressed.

Abstract: A motor control device includes: a power source device including a DC-output power conversion device having a first mode for outputting first voltage and a second mode for outputting second voltage higher than the first voltage; a power supply device; and a control device, and controls a motor. When a flying object takes off, the control device controls the power conversion device in the second mode. When the control device judges that flight information which is one or both of information of a motor parameter obtained along with control for the motor and information of an environmental factor relevant to the flight altitude satisfies a predetermined condition, or when the control device has received an operation mode signal for which the first mode is selected on the basis of the flight information during control for the motor, the control device controls the power conversion device in the first mode.

Abstract: A motor control device includes: a step-down device including a DC-output power conversion device having a first mode for outputting first voltage and a second mode for outputting second voltage lower than the first voltage; a power supply device; and a control device, and controls a motor. When a flying object takes off, the control device controls the power conversion device in the first mode. When the control device judges that flight information which is one or both of information of a motor parameter obtained along with control for the motor and information of an environmental factor relevant to the flight altitude of satisfies a predetermined condition, or when the control device has received an mode signal for which the second mode is selected on the basis of the flight information during control for the motor, the control device controls the power conversion device in the second mode.

Abstract: A method of preheating an unfinished stator as an intermediate product before a stator as a final product for a motor is provided in order to preheat a mold for molding together with the unfinished stator in short time by using preheating facilities with simplified structures. In the method, the mold has a hollow and longitudinal barrel portion and a flange portion extending outward from an end of the barrel portion. The flange portion is arranged at a horizontal position to turn the barrel portion upward and an end of a cylindrical and longitudinal frame is put on the flange portion in a state where a core of the unfinished stator is fitted in the frame. A heat-resistant box of which an underside is opened covers the frame and the mold to surrounded outsides of the frame and the mold.

Abstract: A power converter includes an inverter circuit connected between the positive and negative terminals of a DC power supply, three single-phase bridge circuits each connected in series between an AC terminal of one of different phases of the inverter circuit and a motor, and a power conversion controller that generates gate signals to control operations of the inverter circuit and the three single-phase bridge circuits based on phase voltage commands. When a semiconductor switching element of the single-phase bridge circuits fails, the power conversion controller sets the output voltage of the single-phase bridge circuit of a phase to which the faulty semiconductor switching element belongs to zero to continue operation.

Abstract: A control circuit corrects a reference gain by multiplying the reference gain by a correction value set in association with state-of-charge information of a storage battery, and uses the corrected reference gain as a first gain for controlling a DC/AC inverter, to adjust the slope of frequency drooping characteristic. The correction value is a value that gradually decreases with increase in state-of-charge information of the storage battery, the minimum value of the correction value is N1 which is a real number greater than 0 and corresponding to a first state of charge for stopping charging of the storage battery, and the maximum value of the correction value is N2 which is a real number greater than N1 and corresponding to a second state of charge for stopping discharging of the storage battery.

Abstract: A three-phase multilevel inverter is connected to a first direct-current voltage source having a first voltage. Single-phase inverters are each connected in series to a corresponding phase of the three-phase multilevel inverter, and include a second direct-current voltage source, respectively, each having a second voltage. Combined output voltages, which are combinations of boost voltages generated by the three single-phase inverters and output voltages of the three-phase multilevel inverter, are supplied to a load. The control device adjusts a common mode voltage of the combined output voltages to be within a predetermined allowable range, and variation ranges of the line voltages in the combined output voltages to satisfy a specified condition established with the second voltage as a reference.

Abstract: A control circuit corrects a reference gain by multiplying the reference gain by a correction value set in association with state-of-charge information of a storage battery, and uses the corrected reference gain as a first gain for controlling a DC/AC inverter, to adjust the slope of frequency drooping characteristic. The correction value is a value that gradually decreases with increase in state-of-charge information of the storage battery, the minimum value of the correction value is N1 which is a real number greater than 0 and corresponding to a first state of charge for stopping charging of the storage battery, and the maximum value of the correction value is N2 which is a real number greater than N1 and corresponding to a second state of charge for stopping discharging of the storage battery.

Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.

Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.

Abstract: An ultrasonic testing apparatus includes an ultrasonic probe disposed under an end portion of a pipe laid in the horizontal direction to face the pipe end portion. The probe transmits ultrasonic waves to the end portion of the pipe and receives the ultrasonic waves therefrom. A probe holder housing the probe includes a coupling medium reserver part which surrounds a space between the probe and the end portion of the pipe to contain a coupling medium W. The coupling medium reserver part includes a part body 21 into which the coupling medium is supplied; an annular bellows part, which is attached to the upper side of the part body to internally communicate with the part body, and an annular spacer 23 attached to the upper side of the bellows part, the upper surface of the annular spacer being a flat horizontal surface.

Abstract: An ultrasonic testing equipment of the present invention includes: an ultrasonic probe having a plurality of transducers arranged along a predetermined annular curved surface; a transmission/reception control unit that causes at least two transducers selected from the plurality of the transducers to transmit the ultrasonic waves to and receive the same from the tubular test object and a ultrasonic testing waveform display unit which displays ultrasonic testing waveforms received by the selected transducers radially corresponding to the propagation directions of the ultrasonic waves transmitted from and received by the selected transducers.