Abstract: A motor control device includes a power converter that supplies a three-phase voltage to two motors being connected in parallel, a three-phase power line that connects between one of the two motors and the power converter, a branch three-phase power line that connects between the other of the two motors and the power converter, a switching device having two switches that are provided on the branch three-phase power line, a current detection device that detects three-phase currents flowing in the two motors, and a controller. The controller performs a failure determination of the switching device by identifying a phase of a power line in which no current flows in the three-phase power line and the branch three-phase power line, and, when a failure is detected in one of the two switches in the failure determination, controls to change a state of the other switch, which operates normally, to coincide with a state of the failed switch.

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: A motor control device includes a power converter that supplies a three-phase voltage to two motors being connected in parallel, a three-phase power line that connects between one of the two motors and the power converter, a branch three-phase power line that connects between the other of the two motors and the power converter, a switching device having two switches that are provided on the branch three-phase power line, a current detection device that detects three-phase currents flowing in the two motors, and a controller. The controller performs a failure determination of the switching device by identifying a phase of a power line in which no current flows in the three-phase power line and the branch three-phase power line, and, when a failure is detected in one of the two switches in the failure determination, controls to change a state of the other switch, which operates normally, to coincide with a state of the failed switch.

Abstract: An air-conditioning apparatus includes a plurality of indoor units. Each of the indoor units includes a heat-medium flow adjusting valve and a heat exchanger. The heat-medium flow adjusting valve adjusts the flow rate of a heat medium that flows into the heat-medium flow adjusting valve, and causes the heat medium to flow out of the heat-medium flow adjusting valve. The heat exchanger causes heat exchange to be performed between the heat medium and air. The heat medium flows into the heat exchanger from an inflow side of the heat exchanger. The inflow side of the heat exchanger is connected to an outflow side of the heat-medium flow adjusting valve. The plurality of indoor units are connected in series.

Abstract: An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a heat-source-side expansion device, and a circuit-circuit heat exchanger are connected via a refrigerant pipe and refrigerant circulates, and a heat medium circuit in which a pump, the circuit-circuit heat exchanger, a load-side expansion device, and a load-side heat exchanger are connected via a heat medium pipe and a heat medium circulates. The air-conditioning apparatus includes a radiator that is connected to the heat medium pipe and a control unit that is attached to the radiator. The circuit-circuit heat exchanger exchanges heat between the refrigerant circulating in the refrigerant circuit and the heat medium circulating in the heat medium circuit. The control unit is cooled via the radiator by the heat medium flowing in the heat medium pipe.

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: An air-conditioning apparatus includes a plurality of devices including at least a compressor, and a controller which stores device information indicating the kinds of the devices. The controller reads out a control parameter and a control program for a device which is indicated by kind by the device information, from an external storage device which stores control parameters and control programs for the devices, and controls the device in accordance with the control program.

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 ventilation device includes an outside air heat exchanger disposed between a total heat exchanger and an outside air port, a return air heat exchanger disposed between the total heat exchanger and a return air port, and a supply air heat exchanger disposed between the total heat exchanger and a supply air port. A compressor, a flow switching device, the outside air heat exchanger, an outside air expansion device, and the return air heat exchanger are sequentially connected by pipes, the supply air heat exchanger and a supply air expansion device which are connected in series by pipes are connected in parallel to the outside air heat exchanger and the outside air expansion device by pipes, thereby forming a refrigerant circuit in which refrigerant is circulated.

Abstract: A cooling device includes a cooling-side intermediate heat exchanger that causes heat exchange to be performed between a heat medium and a cooling refrigerant that flows in a cooling refrigerant circuit. A heating device includes a heating-side intermediate heat exchanger that causes heat exchange to be performed between the heat medium and heating refrigerant that flows in a heating refrigerant circuit. The cooling device and the heating device are connected in series in a heat-medium circulation circuit in which the heat medium circulates.

Abstract: An air-conditioning apparatus includes a plurality of indoor units. Each of the indoor units includes a heat-medium flow adjusting valve and a heat exchanger. The heat-medium flow adjusting valve adjusts the flow rate of a heat medium that flows into the heat-medium flow adjusting valve, and causes the heat medium to flow out of the heat-medium flow adjusting valve. The heat exchanger causes heat exchange to be performed between the heat medium and air. The heat medium flows into the heat exchanger from an inflow side of the heat exchanger. The inflow side of the heat exchanger is connected to an outflow side of the heat-medium flow adjusting valve. The plurality of indoor units are connected in series.

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: A motor drive apparatus includes a power converter including an inverter having an upper arm and a lower arm, the inverter being configured to control an operation of an electric motor, and a drive controller configured to apply a dead time for preventing a short circuit between the upper arm and the lower arm, and to control the power converter. The drive controller is configured to control the power converter by switching a first mode in which a first correction value representing a time used to correct a voltage drop due to the dead time is employed to control the power converter, and a second mode in which a second correction value smaller than the first correction value is employed to control the power converter.

Abstract: An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a heat-source-side expansion device, and a circuit-circuit heat exchanger are connected via a refrigerant pipe and refrigerant circulates, and a heat medium circuit in which a pump, the circuit-circuit heat exchanger, a load-side expansion device, and a load-side heat exchanger are connected via a heat medium pipe and a heat medium circulates. The air-conditioning apparatus includes a radiator that is connected to the heat medium pipe and a control unit that is attached to the radiator. The circuit-circuit heat exchanger exchanges heat between the refrigerant circulating in the refrigerant circuit and the heat medium circulating in the heat medium circuit. The control unit is cooled via the radiator by the heat medium flowing in the heat medium pipe.

Abstract: An exhaust heat recovery type of air-conditioning apparatus includes: an air-conditioning-side refrigerant circuit including a first flow switching device, a second flow switching device, and an exhaust-heat recovery heat exchanger connected in parallel to an outdoor heat exchanger and an indoor heat exchanger; and a refrigeration-side refrigerant circuit. The first flow switching device causes the outdoor heat exchanger to communicate with one of a discharge side and a suction side of a first compressor through a pipe. The second flow switching device causes the indoor heat exchanger to communicate with one of the discharge and suction sides of the first compressor through a pipe. The exhaust-heat recovery heat exchanger is connected to the suction side of the first compressor through a pipe, and causes heat exchange between refrigerants. Because of the above configuration, the exhaust heat recovery type of air-conditioning apparatus can use exhaust heat in any of operation modes.

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 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: In an air-conditioning apparatus and a method of detecting an abnormality in a transmission line, the air-conditioning apparatus includes plural facility apparatuses which are connected to each other by a transmission line and communicate with each other. One of the plural facility apparatuses includes: a transmission circuit including an abnormality detection comparator which detects an abnormality in the transmission line, the transmission circuit being provided to detect the abnormality in the transmission line; and a data storage device which stores a reception signal and signal voltage wave-height information indicating that the abnormality in the transmission line is detected. The transmission circuit further compares a voltage value of a reception signal received from another of the plural facility apparatuses through the transmission line with a threshold value set in advance in the abnormality detection comparator.

Abstract: A heat pump system includes a first air-conditioning apparatus, a ventilator, and a refrigerant circuit. The first air-conditioning apparatus includes a compressor, an outdoor-side heat exchanger, an expansion device, and an indoor-side heat exchanger, and air-conditions a first space. The ventilator includes a first auxiliary heat exchanger, and ventilates and air-conditions a second space different from the first space. In the refrigerant circuit, the compressor, the outdoor-side heat exchanger, the first auxiliary heat exchanger, the expansion device, and the indoor-side heat exchanger are sequentially connected by a refrigerant pipe to allow refrigerant to circulate. The first auxiliary heat exchanger is provided in a supply air passage in the ventilator.

Abstract: An air-conditioning apparatus includes a plurality of devices including at least a compressor, and a controller which stores device information indicating the kinds of the devices. The controller reads out a control parameter and a control program for a device which is indicated by kind by the device information, from an external storage device which stores control parameters and control programs for the devices, and controls the device in accordance with the control program.