Abstract: A power converting device includes; one or more backflow preventing elements that prevent electric current from flowing backward from a load side toward a power supply; a commutating unit for performing a commutation operation for causing electric current to flow toward a different path that is connected in parallel with the one or more backflow preventing elements; a malfunction detector for detecting a malfunction of the commutating unit; and a controller configured to control the commutating unit to perform commutation operation just before the recovery current flows through the backflow preventing element from the load side to the power supply and to perform operation control related to protection of the commutating unit on a basis of detection by the malfunction detector.

Abstract: Provided is a power converter for converting electric power between a power source and a load, including: a boosting device including a boost rectifier configured to prevent a backflow of a current from the load side to the power source side, the boosting device being configured to change a voltage of electric power supplied from the power source to a predetermined voltage; a commutation device configured to perform a commutation operation of directing a current flowing through the boosting device to another path; and a controller configured to perform control related to the voltage change of the boosting device and control related to the commutation operation of the commutation device, in which the commutation device is configured to flow, when the commutation device performs the commutation operation, a current generating a voltage causing reverse recovery of the boost rectifier to the commutation device side.

Abstract: For example, backflow preventing means is provided, which reduces a recovery electric current occurring in the event of backflow of an electric current so as to ensure high efficiency, high reliability, etc. The backflow preventing means includes a backflow preventing element, such as a rectifying element, which is connected between an alternating-current power supply and a load and prevents the electric current from flowing backward from the load toward the alternating-current power supply; and commutating means for performing a commutation operation for causing the electric current to flow toward a different path that is connected in parallel with the backflow preventing element, whereby a conduction loss and a loss caused by the electric current can be reduced.

Abstract: A charging/discharging device includes a charging/discharging connector that electrically connects a storage battery and the charging/discharging device, a cable that is connected to the charging/discharging connector at one end and is connected to the charging/discharging device at the other end, a power conversion unit, a control unit that controls an operation of the power conversion unit, and an abnormality detection unit that outputs an abnormality detection signal for stopping an operation of the power conversion unit to at least any of the control unit and the power conversion unit, when an output from a comparator and an ON signal from the control unit are input to an AND circuit.

Abstract: A power converter includes step-up means for varying a voltage applied by a power supply to a predetermined voltage, commutating means for performing a commutation operation for allowing a current flowing through the step-up means to flow through a second path, smoothing means for smoothing a voltage related to outputs of the step-up means and the commutating means to produce power and supplying the power to a load side, and control means for performing control related to voltage varying, such as stepping up, by the step-up means and controlling the commutation operation of the commutating means on the basis of at least one of a voltage and a current related to the step-up means.

Abstract: An object of the present invention is to efficiently heat a refrigerant retained in a compressor. An inverter control unit generates six drive signals corresponding to the respective switching elements of the inverter, and outputs the generated drive signals to the corresponding switching elements of the inverter to cause the inverter to generate a high-frequency AC voltage. Particularly, the inverter control unit generates a drive signal having a switching pattern A for turning on all the three switching elements on a positive voltage side or a negative voltage side of the inverter, and subsequent thereto, generates a drive signal having a switching pattern B for turning on two switching elements of the three switching elements and turning off one switching element thereof.

Abstract: A motor incorporating a power converter including a printed board on which a semiconductor module (an inverter IC), which converts a voltage of an external power supply into a high-frequency voltage and supplies the high-frequency voltage to a stator, is mounted, wherein a high-voltage circuit ground, which is a power ground of a high-voltage main circuit system of the inverter IC, and a low-voltage circuit ground, which is a ground of a control circuit system, which is a low-voltage circuit, of the semiconductor module, are provided on the board, and the high-voltage circuit ground and the low-voltage circuit ground are connected at one point via a resistor.

Abstract: A power conversion device includes a switching control unit that controls respective switching elements constituting a plurality of chopper circuits, a rectified-voltage detection unit, a bus-bar voltage detection unit, and a bus-bar current detection unit. The switching control unit includes an on-duty calculation unit that calculates a reference on-duty of respective drive pulses with respect to the switching elements based on a bus-bar voltage and a bus-bar current, an on-duty correction unit that corrects the reference on-duty to output on-duties of the respective drive pulses based on the bus-bar current, so that change amounts of respective reactor currents become substantially the same, and a drive-pulse generation unit that generates the respective drive pulses, based on the respective on-duties.

Abstract: A power supply switching device and switch board checks whether or not a primary-side voltage of a remote shutoff breaker and a secondary-side voltage thereof become a rated voltage after a commercial power system is recovered from a blackout. Next, when both primary-side voltage and secondary-side voltage become the rated voltage, a contactor is actuated to interconnect a home power system with the commercial power system. Hence, charging of the home power system without causing a user to notice such a charging upon recovery of the commercial power system from a blackout can be prevented. As a result, the safety for the user can be ensured.

Abstract: A converter circuit capable of being compact and light-weight and capable of reducing switching loss, a motor drive control apparatus, an air-conditioner, a refrigerator, and an induction heating cooker provided with the circuit. The converter circuit including: a step-up converter including a rectifier, a step-up reactor, a switching element, and a reverse current prevention element; a step-up converter having a step-up reactor, a switching element, and a reverse current prevention element and connected in parallel with the step-up converter; switching control unit that controls switching elements; and a smoothing capacitor that is provided at the output of the step-up converters. The switching control unit switches the current mode of the current flowing through the step-up reactors into any of a continuous mode, a critical mode, and a discontinuous mode based on a predetermined condition.

Abstract: A drive device driving a power converter that includes a switching element formed from a wide bandgap semiconductor, includes a PWM-signal output unit that generates a drive signal that drives the switching element with PWM; an on-speed reducing unit that, when the switching element is changed from off to on, reduces a change rate of the drive signal; and an off-speed improving unit that, when the switching element is changed from on to off, draws charge from the switching element at a high speed and with a charge drawing performance higher than that at a time when the switching element is changed from off to on.

Abstract: An inverter device, a motor driving device, a refrigerating air conditioner, and a power generation system, which can reduce the recovery loss thereof, are obtained. A plurality of arms that can conduct and block current are provided. At least one of the plurality of arms includes: a plurality of switching elements each having a parasitic diode and being connected in series with each other; and a reverse current diode connected in parallel with the plurality of switching elements.

Abstract: Provided is an alternating-current direct-current converter capable of controlling a harmonic current and improving a power factor at reduced costs.

Abstract: A converter circuit including a step-up converter including a rectifier, a step-up reactor, a switching element, and a reverse current prevention element; a step-up converter having a step-up reactor, a switching element, and a reverse current prevention element and connected in parallel with the step-up converter; a switching control unit that controls switching elements; and a smoothing capacitor that is provided at the output of the step-up converters. The switching control unit switches the current mode of the current flowing through the step-up reactors into any of a continuous mode, a critical mode, and a discontinuous mode based on a predetermined condition.

Abstract: A direct-current power supply device includes a reactor, one end of which is connected to one output end of an alternating-current power supply, a switching unit for short-circuiting the other end of the reactor and the other output end of the alternating-current power supply, a rectifying unit configured to rectify an alternating-current voltage supplied from the alternating-current power supply and generate a voltage equal to or higher than a double voltage, a smoothing capacitor connected to the rectifying unit via backflow preventing diodes and configured to smooth a direct-current voltage output from the rectifying unit, and a control unit configured to control the switching unit and stop the supply of the alternating-current voltage to the rectifying unit in a predetermined period after a predetermined time has elapsed from a zero cross point of the alternating-current voltage output from the alternating-current power supply.

Abstract: For example, backflow preventing means is provided, which reduces a recovery electric current occurring in the event of backflow of an electric current so as to ensure high efficiency, high reliability, etc. The backflow preventing means includes a backflow preventing element, such as a rectifying element, which is connected between an alternating-current power supply and a load and prevents the electric current from flowing backward from the load toward the alternating-current power supply; and commutating means for performing a commutation operation for causing the electric current to flow toward a different path that is connected in parallel with the backflow preventing element, whereby a conduction loss and a loss caused by the electric current can be reduced.

Abstract: A heat pump device that can efficiently feed a high-frequency current to an electric motor and effectively heat a compressor includes a compressor including a compression mechanism configured to compress a refrigerant and a motor configured to drive the compression mechanism, heat exchangers, an inverter configured to apply a voltage to the motor, and an inverter control unit configured to drive the inverter. The inverter control unit includes a stagnation detecting unit configured to determine whether heating of the compressor is necessary and notify the determination result and a high-frequency-alternating-current-voltage generating unit and a PWM-signal generating unit configured to shift to a heating operation mode when the heating is necessary and, in the heating operation mode, generate PWM signals to provide, based on a heating time carrier signal having two or more frequencies, a period in which a reflux current flows.

Abstract: A power converting device includes a rectifying circuit that rectifies voltage of an alternating-current power supply; smoothing means that smoothes output voltage from the rectifying circuit; short-circuiting means that is disposed more closely to the alternating-current power supply than the smoothing means and that short-circuits the alternating-current power supply and controls at least one of electric current and voltage; a reactor that is disposed more closely to the alternating-current power supply than the short-circuiting means; one or more backflow preventing elements that prevent electric current from flowing backward from a load side toward the alternating-current power supply; commutating means for performing a commutation operation for causing electric current to flow toward a different path that is connected in parallel with the one or more backflow preventing elements; malfunction detecting means for detecting a malfunction of the commutating means; and switching control means that performs op

Abstract: A power conversion device according to the present invention includes a power supply, a booster unit (a reactor, a switch) that boosts a voltage supplied from the power supply by switching control, a smoothing circuit that smoothes an output voltage from the booster unit, a rectifier that is arranged between the booster unit and the smoothing circuit to prevent a current reverse flow toward the booster unit, and a commutation unit that is connected to the rectifier in parallel to commutate a current flowing through the rectifier toward itself.

Abstract: An inverter device, a motor driving device, a refrigerating air conditioner, and a power generation system, which can reduce the recovery loss thereof, are obtained. A plurality of arms that can conduct and block current are provided. At least one of the plurality of arms includes: a plurality of switching elements each having a parasitic diode and being connected in series with each other; and a reverse current diode connected in parallel with the plurality of switching elements.