A power unit for producing both alternating current and direct current includes a switcher connected to a direct current source, wherein the switcher includes circuitry configured to produce both alternating current having first characteristics and direct current having second characteristics, wherein the circuitry comprises a plurality of insulated gate bipolar transistor circuits and drive circuits connected to the insulated gate bipolar transistor circuits. The switcher may receive variable voltage and frequency or constant voltage and frequency. In either case, the switcher circuitry is able to provide power of the desired characteristics. The power unit may be used to power aircraft when the aircraft is on the ground.

Disclosed are an inverter control device and method. The method according to an embodiment of the present includes estimating a rotation speed of a motor, determining a slip frequency reference using an energy of a direct current terminal capacitor of an inverter, which provides an output voltage to the motor, and a direct current terminal energy reference when a direct current terminal voltage of the inverter is a certain level or less, and providing a frequency reference determined by adding the rotation speed of the motor and the slip frequency reference to the inverter.

A motor control system includes a DC-to-DC converter including a semiconductor switch and a reactor that cooperates with the switch to convert input-side DC bus voltage across first and second input-side DC buses into predetermined output-side DC bus voltage across first and second output-side DC buses and to output the output-side voltage, control circuitry that controls duty factor of the switch and determine, based on input-side detection value of the input-side voltage and output-side detection value of the output-side voltage, whether there is failure in the system when the factor is 100 percent and reactor-current detection value of reactor current through the reactor is approximately zero, a smoothing capacitor connected to the output-side buses and disposed between the output-side buses, and an inverter that is connected to the capacitor through the output-side buses, converts DC power from the output-side buses into AC power and supplies the power to a motor.

A power supply device includes a controller configured to output, to a power converter, a command value to control at least one of a voltage or a current of power output from the power converter, and acquire a measurement value measured by a measurement unit. The controller is configured to, while power conversion operation is being performed by the power converter, change the command value and determine a deterioration of the power converter based on a mode of a change in the measurement value measured by the measurement unit due to a change in the command value.

A DC power supply device includes a booster circuit generating boosted voltage obtained by boosting DC voltage output from a rectifier circuit and applying the boosted voltage to an inverter circuit, a control unit controlling operation of the booster circuit, and a current detection unit detecting current flowing into and from the inverter circuit. The booster circuit includes a charge accumulation unit including first and second capacitors connected in series and first and second switching elements connected in series. The booster circuit includes a switching unit including backflow prevention elements for preventing backflow of charges from the charge accumulation unit and a current detection unit detecting current flowing into and from the booster circuit. The control unit determines whether to continue driving of an electric motor based on each of detection values of the current detection units.

A DC power supply device includes a booster circuit generating boosted voltage obtained by boosting DC voltage output from a rectifier circuit and applying the boosted voltage to an inverter circuit, a control unit controlling operation of the booster circuit, and a current detection unit detecting current flowing into and from the inverter circuit. The booster circuit includes a charge accumulation unit including first and second capacitors connected in series and first and second switching elements connected in series. The booster circuit includes a switching unit including backflow prevention elements for preventing backflow of charges from the charge accumulation unit and a current detection unit detecting current flowing into and from the booster circuit. The control unit determines whether to continue driving of an electric motor based on each of detection values of the current detection units.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

An embodiment relates to an arrangement for equalizing voltage drops in a power supply mains having a first mains supply and a second mains supply. The arrangement includes at least one first converter system and one second converter system, to which intermediate circuits are coupled and which form a mains coupling as a result. The first mains supply is connected to a distributor via a decoupling inductor, a voltage measurement and a first switch. The second mains supply is connected to the distributor via a second switch, and wherein the mains coupling is arranged parallel to the second switch.

An embodiment relates to an arrangement for equalizing voltage drops in a power supply mains having a first mains supply and a second mains supply. The arrangement includes at least one first converter system and one second converter system, to which intermediate circuits are coupled and which form a mains coupling as a result. The first mains supply is connected to a distributor via a decoupling inductor, a voltage measurement and a first switch. The second mains supply is connected to the distributor via a second switch, and wherein the mains coupling is arranged parallel to the second switch.