Abstract: A power converting device includes power conversion circuitry connected to a power system, voltage amplitude determination circuitry that determines a voltage amplitude of the power system, and control circuitry that controls an output current from the power conversion circuitry to the power system based on an oscillation component of the voltage amplitude determined by the voltage amplitude determination circuitry.

Abstract: A power conversion device includes a switching circuit and a switch driver. The switching circuit includes a plurality of switching elements including a first switching element and a second switching element that are electrically coupled in series. The switch driver includes a first, a second, and a third switching pattern controller. The first switching pattern controller executes a first switching pattern which is set such that a current in a reverse direction flows through the first switching element and the second switching element is off. The second switching pattern controller executes a second switching pattern which is set such that a direction of the current flowing through the first switching element is switched to a forward direction from the reverse direction. The third switching pattern controller executes a third switching pattern which is set such that the first switching element is off and the second switching element is on.

Abstract: A DC-to-DC converter includes a first switching circuit, a second switching circuit, a transformer positioned between an AC side of the first switching circuit and an AC side of the second switching circuit, an inductance element positioned between the transformer and at least one of the AC side of the first switching circuit and the AC side of the second switching circuit, and control circuitry that operates the first switching circuit and the second switching circuit. The control circuitry sets a predetermined operation ratio of the first switching circuit and the second switching circuit to each other, and adjusts, based on the predetermined operation ratio, a first operation period of the first switching circuit and a second operation period of the second switching circuit.

Abstract: An electric power converter according to an embodiment includes a switching unit, a controller, and a second bidirectional switch. The switching unit includes a plurality of first bidirectional switches disposed between a DC power source and an AC load or between a DC load and an AC power source. The controller controls the switching unit to perform power conversion between DC power and AC power. When turning off the second bidirectional switch disposed on a path between one pole of the DC power source or the DC load and the switching unit, the controller turns on the first bidirectional switch connected between the other pole of the DC power source and the AC load or between the other pole of the DC load and the AC power source.

Abstract: A power conversion device includes a switching circuit and a switch driver. The switching circuit includes a plurality of switching elements including a first switching element and a second switching element that are electrically coupled in series. The switch driver includes a first, a second, and a third switching pattern controller. The first switching pattern controller executes a first switching pattern which is set such that a current in a reverse direction flows through the first switching element and the second switching element is off. The second switching pattern controller executes a second switching pattern which is set such that a direction of the current flowing through the first switching element is switched to a forward direction from the reverse direction. The third switching pattern controller executes a third switching pattern which is set such that the first switching element is off and the second switching element is on.

Abstract: An electric power converter according to an embodiment includes a switching unit, a controller, and a second bidirectional switch. The switching unit includes a plurality of first bidirectional switches disposed between a DC power source and an AC load or between a DC load and an AC power source. The controller controls the switching unit to perform power conversion between DC power and AC power. When turning off the second bidirectional switch disposed on a path between one pole of the DC power source or the DC load and the switching unit, the controller turns on the first bidirectional switch connected between the other pole of the DC power source and the AC load or between the other pole of the DC load and the AC power source.

Abstract: A grid interconnection apparatus includes a voltage conversion section including DC/DC converters to step up or down output voltages of DC power sources. The voltage conversion section combines DC power outputs from the DC/DC converters into combined DC power and output the DC power. A power conversion section converts the DC power output from the voltage conversion section into AC power, and outputs the AC power to a power grid. A current detector detects a current input into the power conversion section. A voltage detector detects a voltage input into the power conversion section. A controller controls the DC/DC converters to maximize the power outputs from the DC power sources based on the detected current and the detected voltage.

Abstract: A PWM cycloconverter is disclosed that can switch power supplies without interrupting operation in the event of a power supply abnormality. When a power supply abnormality occurs in three-phase AC power supply 1, power supply abnormality detection circuit 30 outputs power supply abnormality detection signal 120, whereby power supply switch 20 selects and outputs the output voltage of uninterruptible power supply 10. Phase detection circuit switch 43 selects and outputs phase information that is output from uninterruptible power supply phase detection circuit 41. Uninterruptible power supply phase detection circuit 41 detects the phase of uninterruptible power supply 10 from before the occurrence of the power supply abnormality, whereby accurate phase information of uninterruptible power supply 10 can be output even immediately after phase detection circuit switch 43 switches the phase information that is output. As a result, operation is not interrupted when switching power supplies.

Abstract: A protection apparatus and a protection method of a PWM cycloconverter wherein when the PWM cycloconverter is shut off, a surge voltage or an overcurrent is not produced on the output side are provided. A protection apparatus of a PWM cycloconverter is made up of fault detection means 30 for detecting a fault of the PWM cycloconverter, operation stop means 25 for turning off at least some of the uni-directional semiconductor switches 3 to 20 of the PWM cycloconverter if a fault signal occurs, continuous flow means for allowing a load current of the PWM cycloconverter to continuously flow if at least some output phases of the PWM cycloconverter become open, and protection switching means 50 for turning on and off the unidirectional semiconductor switches of the PWM cycloconverter based on the fault signal output from the fault detection means.