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: 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 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: 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 power converter includes a power converting module and a gate drive circuit that includes first and second drive circuits and a power supply module including a limiting resistor, a bootstrap diode, and a bootstrap capacitor, and configured to generate a voltage to be supplied to the second drive circuit. The bootstrap capacitor is charged when a switching element connected to a reference potential side performs switching. A charging period of the bootstrap capacitor includes at least first and second periods. In the first period, the switching element is driven by a pulse signal having a first pulse width. In the second period, the switching element is driven by a pulse signal having a second pulse width greater than the first one. The first pulse width in the first period is determined based on an allowable magnitude of a voltage drop of the control power supply in the first period.

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 conversion device supplies power to a load. The power conversion device includes a power conversion unit, a control unit, a noise suppression unit, and an error detection unit. The power conversion unit receives power from a first power source. The control unit controls the power conversion unit. The noise suppression unit is connected between the first power source and the power conversion unit and outputs a noise suppression signal to suppress noise generated from the power conversion unit. When an error condition is established, the error detection unit detects an error. The error condition indicates that the error has occurred in the power conversion device or the load. The error condition includes a condition that an amount of noise generated from the power conversion unit is larger than a reference value.

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 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 bridge circuit that includes at least two legs each including switching elements connected in series, and converts an alternating-current voltage output from an 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; a zero crossing detecting unit that detects a voltage polarity of the alternating-current power supply; and a control unit that controls ON and OFF of the switching elements depending on outputs of the power-supply current detecting unit and the zero crossing detecting unit, in which a dead time that is set for switching and includes a change in the voltage polarity of the alternating-current power supply is longer than a dead time that is set for switching and does not include a change in the polarity.

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.

Abstract: An outdoor unit includes a housing that includes a front panel and a back panel facing the front panel. The outdoor unit further includes a bell mouth provided on the front panel and a heat dissipator that dissipates heat generated by electric components. A windward end surface and a leeward end surface of the heat dissipator are, when viewed from above, placed in a region between a virtual surface and the back panel, the virtual surface being a virtual surface that is in contact with an end of the bell mouth on a side of the back panel and is parallel to an inner surface of the front panel.

Abstract: An over-current protection circuit for a motor capable of selecting one of a plurality of connection states has a plurality of decision circuits, a combining circuit, and a nullifying circuit. The combining circuit combines results of the comparisons in the plurality of decision circuits. The nullifying circuit nullifies part of the comparisons in the plurality of decision circuits. The number of outputs of the over-current protection circuit is one, so that for controlling the driving and stopping of the inverter needs just one terminal is required for receiving the output of the combining circuit. Moreover, because the over-current protection circuit is formed of hardware, the protection can be performed at a high speed.

Abstract: A motor driving device is a device for driving a motor including stator windings, includes: a connection switching unit that is connected to the stator windings, includes circuits including semiconductor switches, and switches connection condition of the stator windings to either of first connection condition and second connection condition different from the first connection condition by setting the semiconductor switches to ON or OFF; and an inverter that supplies AC drive voltages to the stator windings.

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 is connected between a power supply source of a first direct current power and a power supply destination of a second direct current power obtained by performing power conversion on the first direct current power. The power converter includes: a switching element; a reactor; a first diode; a first capacitor; a second diode. The reactor is connected to a first end of the switching element. The first end of the switching element and a first end of the reactor are connected to a first connection point. A cathode of the first diode is connected to a second end of the reactor. The cathode of the first diode and the second end of the reactor are connected to a second connection point. The second diode includes an anode connected to the first connection point and a cathode connected to the power supply destination.

Abstract: An outdoor unit includes a housing that includes a front panel having an outlet for an airflow, a back panel facing the front panel, a left side panel, a right side panel facing the left side panel, a bottom panel, and a top panel facing the bottom panel. The outdoor unit further includes a control substrate that is provided in the housing and provided with an electric component, an electric component box in which the control substrate is provided, and a heat dissipator that is provided between the top panel and the electric component box and dissipates heat generated by the electric component. A second region surrounded by the heat dissipator, the back panel, the front panel, the electric component box, and the top panel is formed on a windward side of the heat dissipator.

Abstract: A direct-current power supply device includes a reactor, a bridge circuit that converts alternating-current voltage output from an alternating-current power supply, which is connected to the reactor, into direct-current voltage, a capacitor that smoothes the output voltage of the bridge circuit, a current detector that detects a first current flowing as an alternating current between the alternating-current power supply and the bridge circuit, a current detector that detects a second current flowing as a direct current between the bridge circuit and the capacitor, an overcurrent determination unit that determines on the basis of a detected first current value whether or not the first current is an overcurrent, and an overcurrent determination unit that determines on the basis of a detected second current value whether or not the second current is an overcurrent.