Abstract: A power converter includes a rectifier configured to rectify an AC voltage supplied from an AC power supply, a booster circuit configured to boost the voltage rectified by the rectifier, a smoothing capacitor configured to smooth the voltage output from the booster circuit, a power module configured to convert a DC voltage obtained by smoothing the output voltage by the smoothing capacitor into an AC voltage, and a snubber capacitor configured to absorb a surge voltage superimposed on the DC voltage to be input to the power module. The snubber capacitor is mounted in the power module.

Abstract: This power conversion device includes: a current detection unit for detecting current flowing through a rotary electric machine; a switching pattern determination unit for determining a switching pattern on the basis of the detected current, a current prediction value, a current command value, and a current harmonic command value; and a power conversion unit for outputting AC power to the rotary electric machine in accordance with the switching pattern, wherein the switching pattern determination unit determines the switching pattern so that the current value follows the current command value and the current harmonic becomes equal to or smaller than a limit value.

Abstract: A harmonic current compensating device according to an embodiment of the present disclosure is a harmonic current compensating device including a power converter including at least a pair of arms each including a switching element, the harmonic current compensating device being configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, in which the switching element includes a unipolar device using a wide bandgap semiconductor.

Abstract: A power converter that includes a rectifier rectifying a voltage supplied from a three-phase AC power supply, a voltage step-down circuit including a voltage step-down switching element, a reactor, a backflow prevention element, and a smoothing capacitor and stepping down a DC voltage supplied from the rectifier, and an inverter circuit converting the DC voltage smoothed by the smoothing capacitor into an AC voltage. The power converter includes an imbalance determining unit determining, based on states of the voltage step-down circuit and the smoothing capacitor, whether or not voltage imbalance has occurred in the three-phase AC power supply and a voltage step-down control unit performing switching of the voltage step-down switching element in a case where the imbalance determining unit determines that the voltage imbalance has occurred.

Abstract: This power conversion device includes: a current detection unit for detecting current flowing through a rotary electric machine; a switching pattern determination unit for determining a switching pattern on the basis of the detected current, a current prediction value, a current command value, and a current harmonic command value; and a power conversion unit for outputting AC power to the rotary electric machine in accordance with the switching pattern, wherein the switching pattern determination unit determines the switching pattern so that the current value follows the current command value and the current harmonic becomes equal to or smaller than a limit value.

Abstract: A refrigeration cycle apparatus includes a refrigerant circuit through which refrigerant circulates, a control box in which equipment for controlling the refrigeration cycle apparatus is accommodated, and a refrigerator for cooling a heat emitting body exposed from an opening of the control box. The heat emitting body is the equipment accommodated in the control box. The refrigerator includes a cooling body in contact with the heat emitting body, and a refrigerant pipe through which the refrigerant circulating through the refrigerant circuit passes to cool the cooling body. The refrigerant pipe is in contact with the cooling body. The pipe contact surface is different from the heating-body contact surface. The cooling body has a recessed portion at which the cooling body and the heat emitting body are not in contact with each other. The recessed portion is formed in the heating-body contact surface and spaced from the control box.

Abstract: A harmonic current compensating device according to an embodiment of the present disclosure is a harmonic current compensating device including a power converter including at least a pair of arms each including a switching element, the harmonic current compensating device being configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, in which the switching element includes a unipolar device using a wide bandgap semiconductor.

Abstract: An outdoor unit comprises a casing, a fan, a heat exchanger, an electrical component, a heat radiation member, and a duct. The casing is provided with an air outlet. The fan is disposed inside the casing and configured to blow air to the outside of the casing via the air outlet. The heat exchanger is disposed inside the casing at a position lower than the fan. The electrical component is disposed inside the casing at a position lower than the heat exchanger. The heat radiation member is connected to the electrical component inside the casing. The duct is configured to accommodate at least part of the heat radiation member inside the casing and extend in the vertical direction. An upper end of the duct is configured to protrude upward higher than a lower end of the heat exchanger.

Abstract: A power converter includes a rectifier configured to rectify an AC voltage supplied from an AC power supply, a booster circuit configured to boost the voltage rectified by the rectifier, a smoothing capacitor configured to smooth the voltage output from the booster circuit, a power module configured to convert a DC voltage obtained by smoothing the output voltage by the smoothing capacitor into an AC voltage, and a snubber capacitor configured to absorb a surge voltage superimposed on the DC voltage to be input to the power module. The snubber capacitor is mounted in the power module.

Abstract: An air-conditioning apparatus includes a refrigerant pipe through which refrigerant that flows through the refrigeration cycle passes; a pipe-side plate thermally connected to the refrigerant pipe; a control box thermally connected to the pipe-side plate and containing an electric component including a heating element; a housing of an outdoor unit, the housing containing the pipe-side plate and the control box; a positioning element fixing the pipe-side plate and the control box to each other; and a fastening element fixing the control box and the positioning element to each other. At least one side surface of the housing has a work opening. A front portion of the control box is positioned closer to the work opening in the housing, and a rear portion of the control box is positioned closer to a rear surface of the housing, the rear surface facing the side surface having the work opening.

Abstract: A power conversion device includes a rectifier module configured to rectify an alternating current supplied from an alternating-current power supply; an inverter unit configured to convert a direct current rectified by the rectifier module into an alternating current, output the alternating current to an electric motor, and drive the electric motor; and a cooling mechanism. The inverter unit has a plurality of inverter modules. The cooling mechanism is configured to cool the rectifier module and the plurality of inverter modules. Thermal resistance between the rectifier module and the cooling mechanism and thermal resistance between the plurality of inverter modules and the cooling mechanism are different from each other.

Abstract: A power converter that includes a rectifier rectifying a voltage supplied from a three-phase AC power supply, a voltage step-down circuit including a voltage step-down switching element, a reactor, a backflow prevention element, and a smoothing capacitor and stepping down a DC voltage supplied from the rectifier, and an inverter circuit converting the DC voltage smoothed by the smoothing capacitor into an AC voltage. The power converter includes an imbalance determining unit determining, based on states of the voltage step-down circuit and the smoothing capacitor, whether or not voltage imbalance has occurred in the three-phase AC power supply and a voltage step-down control unit performing switching of the voltage step-down switching element in a case where the imbalance determining unit determines that the voltage imbalance has occurred.

Abstract: A power conversion device includes a filter unit including an active noise canceler including an active element reducing low frequency components contained in common mode noise of noise and lower than a predetermined threshold frequency, and a passive filter including a passive element reducing normal mode noise of noise and high frequency components contained in the common mode noise of noise and equal to or higher than the threshold frequency. The active noise canceler includes a choke coil having a primary winding to which a first alternating current power is supplied and a secondary winding outputting a current, a filter circuit reducing a high frequency region of the current of the secondary winding, an amplifier circuit amplifying output of the filter circuit and securing a required amount of the current, and a current injection circuit injecting output of the amplifier circuit to each phase of the first alternating current power.

Abstract: A heat pump device includes a compressor including a motor, a heat exchanger, an inverter, and an inverter control unit. The inverter control unit generates a drive signal for the inverter. When the compressor is heated, the inverter control unit applies, to the motor, a high-frequency voltage with which the motor cannot be rotationally driven; estimates a magnetic pole position indicating a stop position of a rotor of the motor; determines an amplitude and a phase of a voltage command based on an estimation result of the magnetic pole position and a necessary amount of heat, and generates a drive signal.

Abstract: A power conversion device includes a filter unit including an active noise canceler including an active element reducing low frequency components contained in common mode noise of noise and lower than a predetermined threshold frequency, and a passive filter including a passive element reducing normal mode noise of noise and high frequency components contained in the common mode noise of noise and equal to or higher than the threshold frequency. The active noise canceler includes a choke coil having a primary winding to which a first alternating current power is supplied and a secondary winding outputting a current, a filter circuit reducing a high frequency region of the current of the secondary winding, an amplifier circuit amplifying output of the filter circuit and securing a required amount of the current, and a current injection circuit injecting output of the amplifier circuit to each phase of the first alternating current power.

Abstract: An outdoor unit comprises a casing, a fan, a heat exchanger, an electrical component, a heat radiation member, and a duct. The casing is provided with an air outlet. The fan is disposed inside the casing and configured to blow air to the outside of the casing via the air outlet. The heat exchanger is disposed inside the casing at a position lower than the fan. The electrical component is disposed inside the casing at a position lower than the heat exchanger. The heat radiation member is connected to the electrical component inside the casing. The duct is configured to accommodate at least part of the heat radiation member inside the casing and extend in the vertical direction. An upper end of the duct is configured to protrude upward higher than a lower end of the heat exchanger.

Abstract: An air-conditioning apparatus includes a refrigerant pipe through which refrigerant that flows through the refrigeration cycle passes; a pipe-side plate thermally connected to the refrigerant pipe; a control box thermally connected to the pipe-side plate and containing an electric component including a heating element; a housing of an outdoor unit, the housing containing the pipe-side plate and the control box; a positioning element fixing the pipe-side plate and the control box to each other; and a fastening element fixing the control box and the positioning element to each other. At least one side surface of the housing has a work opening. A front portion of the control box is positioned closer to the work opening in the housing, and a rear portion of the control box is positioned closer to a rear surface of the housing, the rear surface facing the side surface having the work opening.

Abstract: A refrigeration cycle apparatus includes a refrigerant circuit through which refrigerant circulates, a control box in which equipment for controlling the refrigeration cycle apparatus is accommodated, and a refrigerator for cooing a heat emitting body exposed from an opening of the control box. The heat emitting body is the equipment accommodated in the control box. The refrigerator includes a cooling body in contact with the heat emitting body, and a refrigerant pipe through which the refrigerant circulating through the refrigerant circuit passes to cool the cooling body. The refrigerant pipe is in contact with the cooling body. The pipe contact surface is different from the heating-body contact surface. The cooling body has a recessed portion at which the cooling body and the heat emitting body are not in contact with each other. The recessed portion is formed in the heating-body contact surface and spaced from the control box.

Abstract: A backflow preventing device includes a backflow preventing element that is connected between a power supply and a load and that prevents electric current from flowing backward from the load side toward the power supply side, and a commutating device that performs a commutation operation for causing the electric current to flow to a commutation path connected in parallel with the backflow preventing element. A plurality of elements including at least one or more of elements constituting the commutating device are configured as a module, so that, for example, the device can be reduced in size. Moreover, a simplified heat-dissipation design and a simplified air-duct design can be achieved.

Abstract: A power converter includes a transformation circuit configured to transform a rectified voltage, and a converter control unit configured to control a switching element of the transformation circuit. The converter control unit calculates a current command value based on a line voltage or the phase voltage, calculates a current deviation between the current command value and the reactor current, and calculates a switching command value from the current deviation. The converter control unit includes a plurality of integrators for the respective different phase angles of a power supply voltage. The integrator corresponding to a power supply phase angle is caused to accumulate the current deviation, and the integrator corresponding to a phase angle that is advanced by a set delay phase from the power supply phase angle is caused to output the control amount. A switching signal is generated with use of the control amount and the switching command value.