Abstract: A power converter includes: a rectifying and boosting unit that rectifies first alternating-current power supplied from a commercial power supply and boosts a voltage of the first alternating-current power; a capacitor connected to an output end of the rectifying and boosting unit; an inverter to convert power output from the rectifying and boosting unit and the capacitor into second alternating-current power, and output the second alternating-current power to a device; and a control unit that reduces a current flowing through the capacitor by controlling the rectifying and boosting unit and by controlling the inverter such that the inverter outputs, to the device, the second alternating-current power containing a ripple dependent on a ripple of power flowing from the rectifying and boosting unit into the capacitor. The control unit controls operation of the power converter in accordance with an air-conditioning condition of an air conditioner.

Abstract: The outdoor unit (1000) includes a housing whose inside is divided into a fan chamber (110) and a machine chamber (120). A compressor and a reactor that are heat-generating components are provided in a lower area of the machine chamber (120). An electric board (50) including a printed circuit board (51) and an electric component (52), and an electric component box (10) constituted by an inner box (11) and an outer box (12) and accommodating the electric board are provided above the heat-generating components. A lower face of the inner box (first thermal insulation plate) and a lower face of the outer box (second thermal insulation plate) constitute a double thermal insulation plate (10a).

Abstract: An outdoor unit includes a housing having a front surface formed with an outlet and a back surface facing the front surface, an airflow flowing through the outlet; a substrate horizontally placed in the housing, an electric component being mounted on the substrate; and a heat dissipator including a plurality of fins, each of the fins having a heat dissipation surface, the heat dissipator dissipating, due to the airflow, heat generated by the electric component. The heat dissipation surface of each of the fins is parallel to the back surface or is angled at greater than 0 degrees and less than 90 degrees relative to the back surface in top view.

Abstract: A power conversion apparatus includes a converter circuit converting alternating current voltage output from an AC power supply into direct current voltage. The converter circuit includes unit converters. The power conversion apparatus generates a reference duty based on detection values of a current detector and a voltage detector, and generates a pulse width modulation signal based on a result of comparison between a carrier signal and a corrected duty obtained by correcting the reference duty. When a first reference duty in a first carrier period differs from a second reference duty in a second carrier period subsequent to the first carrier period, a first corrected duty of a first phase in a first carrier period in one power supply period after and a second corrected duty of a second phase in the first carrier period in one power supply period after are controlled to have different values.

Abstract: A power converter includes: a rectifying and boosting unit that rectifies first alternating-current power supplied from a commercial power supply and boosts a voltage of the first alternating-current power; a capacitor connected to an output end of the rectifying and boosting unit; an inverter to convert power output from the rectifying and boosting unit and the capacitor into second alternating-current power, and output the second alternating-current power to a device; and a control unit that reduces a current flowing through the capacitor by controlling the rectifying and boosting unit and by controlling the inverter such that the inverter outputs, to the device, the second alternating-current power containing a ripple dependent on a ripple of power flowing from the rectifying and boosting unit into the capacitor. The control unit controls in accordance with a load state.

Abstract: An outdoor unit includes: a housing; a compressor placed in the housing; a heat exchanger placed in the housing; and a blower placed in the housing, the blower admitting air from outside the housing and passing the air through the heat exchanger. Furthermore, the outdoor unit includes: a partition plate partitioning the housing into a compressor chamber and a blower chamber; a board on which an electronic component is mounted; a heat dissipator placed in the blower chamber and adjacent to the partition plate, the heat dissipator including a base and a plurality of fins, the base having a fin formation surface, the fins projecting from the fin formation surface, the heat dissipator dissipating heat of the electronic component; and a duct covering the heat dissipator. When the fins are viewed from the fin formation surface side, the fins extend toward the blower side from the partition plate side.

Abstract: A power converting apparatus includes a first arm including a switching element and a switching element connected in series, a second arm connected in parallel with the first arm and including a switching element and a switching element connected in series, a reactor having one end connected to the switching element and the switching element and the other end connected to a single-phase alternating-current power supply, and a smoothing capacitor connected in parallel with the first arm and the second arm. The power converting apparatus includes a driving circuit driving the switching element, a bootstrap circuit, and a diode adjusting a power supply voltage, wherein a first voltage at which a forward current starts to flow to the diode is lower than a second voltage at which a forward current starts to flow in a body diode formed in the second switching element.

Abstract: A motor drive device includes a reactor, a converter circuit, a capacitor, an inverter circuit, and overcurrent determination units. The converter circuit converts a first AC voltage output from an AC power supply into a DC voltage. The capacitor smooths a second voltage on the DC side of the converter circuit. The inverter circuit converts DC power stored in the capacitor into AC power. One of the overcurrent determination units determines overcurrent based on a detected value of the first AC current, flowing between the AC power supply and the converter circuit. Another overcurrent determination unit determines overcurrent based on a detected value of the second DC current, flowing between the converter circuit and the capacitor. The converter and inverter circuits stop operating when the determination result of one of the overcurrent determination units indicates an overcurrent.

Abstract: A power converting apparatus includes a converter, a smoothing unit, inverters, and a control unit. The inverters are connected to the converter, the inverters being in parallel connection with each other. The inverter converts power output from the smoothing unit into a first alternating-current power, and outputs the first alternating-current power to a device in which a motor is installed. The inverter converts power outputted from the smoothing unit into a second alternating-current power, and outputs the second alternating-current power to a device in which a motor is installed. The control unit controls an operation of the converter and the inverters to reduce a current flowing in the smoothing unit and concurrently controls an operation of the inverter in accordance with an operation state of the inverter and a load unit including the device.

Abstract: An outdoor machine includes a housing including a front panel with an opening formed therein; a blower disposed in the housing; a bell mouth disposed in the outer periphery of the blower and connected to the opening; a control board on which an electric component is mounted, the control board being provided in the housing; a heat radiation part that radiates heat generated by the electric component; and a vent deflector that covers the heat radiation part, and forms a ventilation flue through which air generated by the blower flows in the heat radiation part, in which the vent deflector 20 is not provided in a region between a virtual plane S and the front panel, the virtual plane S covering the entire periphery of an edge of the bell mouth and extending in parallel with the front panel.

Abstract: A control device controls operation of a power conversion apparatus including a converter, a smoothing capacitor, and an inverter. The control device includes a voltage command calculation unit, a torque ripple compensation command calculation unit, and a beat component compensation command calculation unit. The voltage command calculation unit calculates a voltage command including a first compensation command to reduce a first torque ripple pulsating at twice a frequency of a power-supply voltage. The torque ripple compensation command calculation unit calculates a second compensation command to reduce a second torque ripple pulsating at a rotational frequency of a motor. The beat component compensation command calculation unit calculates a third compensation command to reduce a third torque ripple caused by the first torque ripple and by the second torque ripple.

Abstract: A power converter includes a converter, a smoothing capacitor, an inverter, and a controller. The converter rectifies a power supply voltage applied from an alternating-current power supply. The smoothing capacitor smooths a rectified voltage output from the converter into a direct-current voltage including a ripple. The inverter converts the direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage to be applied to a motor. The controller performs control such that a first physical quantity representing an operation state of the converter is equal to a second physical quantity representing an operation state of the inverter.

Abstract: A power converter includes a converter that rectifies an alternating-current voltage applied from an alternating-current power supply, a capacitor connected to output ends of the converter, an inverter connected both ends of the capacitor, and a controller that controls an operation of the inverter. A voltage output from the converter includes a ripple component due to a voltage fluctuation of the alternating-current voltage. When the controller performs acceleration and deceleration control on the motor, the controller changes a rotational speed command from a command value during the normal control, in a first period in which a rotational speed of the motor is in a first speed range.

Abstract: An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate a DC voltage, an inverter to generate three-phase AC voltages from the DC voltage, a motor to produce a driving force for driving the compressor with a plurality of coils, the three-phase AC voltages being applied to the coils, a connection switching unit to switch connection states of the coils between a first connection state and a second connection state, and a controller to detect an abnormality of the connection switching unit.

Abstract: A power converter includes a converter, a smoothing capacitor, an inverter, and a single calculator. The converter includes a switching element and rectifies a power supply voltage applied from an alternating-current power supply. The smoothing capacitor smooths a rectified voltage output from the converter into a direct-current voltage including a ripple. The inverter converts the direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage for a motor. The calculator performs control such that a first physical quantity representing an operation state of the converter is equal to a second physical quantity representing an operation state of the inverter.

Abstract: A power supply includes: a converter circuit including boost circuits, the converter circuit boosting a voltage output from a power source; a current detector that detects a first current flowing between the power source and the converter circuit; current detectors that each detect a second current, the second current being a sum current of currents flowing in switching elements of the boost circuits; and overcurrent determiners that determine whether the second currents are overcurrent on the basis of detection values of the second currents. When a result of the determination made by corresponding one of the overcurrent determiners indicates overcurrent, the boost circuits stop operating.

Abstract: A power conversion apparatus includes a rectification and boost unit that rectifies a first alternating-current power supplied from a commercial power supply and boosts voltage of the first alternating-current power; a capacitor connected to output terminals of the rectification and boost unit; an inverter that is connected across the capacitor, converts power output from the rectification and boost unit and the capacitor into a second alternating-current power, and outputs the second alternating-current power to a load including a motor; and a control unit that performs operation control on the rectification and boost unit, and performs operation control on the inverter to cause the second alternating-current power that includes a pulsation based on a pulsation of power that flows into the capacitor from the rectification and boost unit to be output from the inverter to the load, to restrain a current that flows into the capacitor.

Abstract: A converter device includes: a power conversion circuit including a reactor and a switching element, rectifying a voltage of alternating-current power supplied from an alternating-current power supply to a direct-current voltage, and boosting and outputting the direct-current voltage; a current detector detecting a current flowing in the reactor; a filter circuit filtering a first signal detected by the current detector; and a control unit generating a control signal on the basis of a carrier and a second signal generated by the filter circuit and controlling, on the basis of the control signal and with a first period, the switching element, the first period being a period of the carrier. The filter circuit cuts off a repetition frequency component in the first period and passes a repetition frequency component in a second period, the second period being longer than the first period.

Abstract: A direct-current power supply apparatus includes: a reactor having one end connected to an alternating-current power supply; a bridge circuit, connected to an opposite end of the reactor, converting an alternating-current first voltage output from the alternating-current power supply into a direct-current voltage; and a current detector detecting an alternating current flowing between the alternating-current power supply and the bridge circuit. The reactor reduces an inductance in accordance with an increase of the alternating current and, when the alternating current exceeds a first current, has an inductance lower than one third of an inductance at which a current does not flow in the reactor. The bridge circuit performs an active operation when the detection value of the alternating current is larger than or equal to the first current and performs a passive operation when the detection value of the alternating current is lower than the first current.

Abstract: A power converting apparatus includes: a reactor that includes a first terminal and a second terminal, the first terminal being connected to an alternating-current power supply; a bridge circuit that is connected to the second terminal of the reactor, includes at least one or more switching elements, and converts an alternating-current voltage output from the alternating-current power supply into a direct-current voltage; a power-supply current detecting unit that detects a current from the alternating-current power supply; and a control unit that controls ON and OFF of the switching elements depending on a current value detected by the power-supply current detecting unit, in which two or more current thresholds for controlling ON and OFF of the switching elements are included.