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 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 refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.

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: In a motor driving apparatus having an inverter for driving a motor capable of switching between a star connection and a delta connection, when currents detected by winding current detecting elements detecting currents flowing through windings become excessive, the inverter is made to stop. Moreover, inverter output currents are calculated after removing a circulating current component at the time of the delta connection, from the winding currents detected by the winding current detecting elements, and the inverter is controlled using the calculated inverter output currents. Because over-current protection is performed based on the detected values of the winding currents, it is possible to prevent demagnetization taking account oSf the circulating current. Also, the inverter control is prevented from being affected by the circulating current in the delta connection. Accordingly, it is possible to reduce the number of the current detecting elements, and perform the over-current protection and control properly.

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: 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 harmonic suppression device includes a power converter that generates a harmonic suppression current that is an electric current for suppressing a harmonic current flowing in a power line and outputs the generated harmonic suppression current to the power line, a communication unit that exchanges signals with other harmonic suppression devices, and a controller that controls the power converter based on a signal received by the communication unit.

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: In a power converter, modules are electrically interconnected by a busbar and joint members. Each joint member has a connecting portion formed on one side and a connecting portion formed on the other side, with respect to a bisector bisecting the width. The busbar has a connecting portion on one side with respect to a bisector bisecting the width. For a 200 V power supply specification, one end of each of two busbars is fixed to one joint member. For a 400 V power supply specification, one end of one busbar is fixed to one joint member.

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: A motor driver includes an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor. The inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage. The second integer is smaller than the first integer.

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 heat pump apparatus includes an outdoor heat exchanger, a fan configured to introduce outdoor air into the outdoor heat exchanger, and a control device configured to control a defrosting operation of the outdoor heat exchanger. The fan rotates at a first rotational speed within a first period, after the defrosting operation is finished and the fan starts rotating. The fan rotates at the first rotational speed within a second period, after a non-defrosting operation is finished and the fan starts rotating. The first period is shorter than the second period.

Abstract: An electric-motor driving apparatus according to the present invention is the electric-motor driving apparatus that drives an electric motor having a winding structure in which a first multi-phase winding and a second multi-phase winding are wound and includes a first DC/AC converter connected to the first multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a second DC/AC converter connected to the second multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a first three-phase switching unit to perform connecting and disconnecting between phases of the first multi-phase winding, a second three-phase switching unit to perform connecting and disconnecting between phases of the second multi-phase winding, and a winding switching unit to perform connecting and disconnecting between the first multi-phase winding and the second multi-phase winding.

Abstract: An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate DC voltage, an inverter to generate three-phase AC voltage from the DC voltage, a motor to generate driving force to drive the compressor by using a plurality of coils to which the three-phase AC voltage is applied, a connection switching unit to switch connection states of the plurality of coils, and an outdoor control device to control the connection switching unit. The outdoor control device restricts the switching of the connection states when a switching count of the connection states exceeds a count threshold value.

Abstract: A motor system according to the present invention includes: a motor including a first winding portion and a second winding portion, the second winding portion having a larger number of turns than the first winding portion; a first inverter connected to the first winding portion; and a second inverter connected to the second winding portion.

Abstract: Provided is a motor driving apparatus used for driving a motor including a first winding group and a second winding group to which three-phase alternating-current voltages are applied. The motor driving apparatus includes a first inverter and a second inverter; the first inverter applies an alternating-current voltage to the first winding group; and the second inverter applies an alternating-current voltage to the second winding group. A first induced voltage detector, a second induced voltage detector, and a third induced voltage detector are provided as voltage detectors for detecting induced voltages induced either in the first winding group or in the second winding group.

Abstract: A harmonic suppression device includes a power converter that generates a harmonic suppression current that is an electric current for suppressing a harmonic current flowing in a power line and outputs the generated harmonic suppression current to the power line, a communication unit that exchanges signals with other harmonic suppression devices, and a controller that controls the power converter based on a signal received by the communication unit.

Abstract: A motor driving device and an air conditioner are capable of increasing the efficiency in a low speed region in which a motor performs low speed rotation. The motor driving device that is a motor driving device for driving a motor including stator windings, includes: a connection switching unit that switches connection condition of the stator windings to either of first connection condition and second connection condition different from the first connection condition; and an inverter that converts a DC voltage into AC drive voltages and supplies the AC drive voltages to the stator windings. The inverter includes MOS transistors as switching elements.