An AC/DC converter includes: a charge accumulation unit including first and second capacitors connected in series; a switching unit including a switch unit; a control unit; a switch drive unit; and first current and second current detection units. The switch unit includes first and second switching elements connected in series. The switching unit switches between charging and non-charging of each of the first and second capacitors. The switch drive unit causes the first and second switching elements to perform an ON/OFF operation exclusively to each other. A current detector of the first current detection unit is disposed between a rectifier circuit and the switch unit. The control unit detects a current flowing through the switch unit on the basis of based on a difference value between a detection value of a first current detected by the first current detection unit and a detection value of a second current detected by the second current detection unit.

To reduce the possibility that temperature of refrigerant discharged from a compressor of a refrigeration apparatus becomes excessively high by controlling torque of a motor built into the compressor, the compressor includes the motor having rotation thereof controlled by inverter control. An inverter controller controls torque of the motor using inverter control when operation frequency of the compressor is at least one value within a range of from 10 Hz to 40 Hz. When at least the operation frequency is within the range of from 10 Hz to 40 Hz, torque of the motor is controlled, and under a predetermined condition in which temperature of refrigerant discharged from the compressor easily becomes excessively high, a device controller controls devices provided in a refrigerant circuit such that refrigerant sucked into the compressor is placed in a wet vapor state.

A refrigerator and a method for controlling the same are disclosed. The refrigerator may minimize the size and material cost of the control system by controlling the internal temperature and the speed of a compressor using a thermostat used in the conventional low-capacity/low-cost refrigerator without using a system controller equipped with various sensors (internal sensors and/or external sensors) capable of controlling the internal temperature. In addition, since an inverter controller capable of controlling a BDLC compressor estimates the internal/external temperature based on operation information of the compressor, and determines the internal load, it may save energy and reduce vibrations and noise, which are the largest disadvantages of a constant-speed compressor, thereby improving satisfaction of the consumer. In addition, the BLDC compressor may be started and operated stably by applying a differentiated algorithm of the inverter controller.

An air conditioning system of a vehicle having an internal combustion engine includes a condenser configured to receive refrigerant output by an electric compressor and transfer heat from the refrigerant within the condenser to air passing the condenser. A first evaporator is configured to receive refrigerant from the condenser when a first control valve is open and transfer heat from air passing the first evaporator to the refrigerant within the first evaporator. A first blower is configured to blow air across the first evaporator to a first section of a cabin of the vehicle. A second evaporator is configured to receive refrigerant from the condenser when a second control valve is open and transfer heat from air passing the second evaporator to the refrigerant within the second evaporator. A second blower is configured to blow air across the second evaporator to a second section of the cabin of the vehicle.

An air conditioning system of a vehicle having an internal combustion engine includes a condenser configured to receive refrigerant output by an electric compressor and transfer heat from the refrigerant within the condenser to air passing the condenser. A first evaporator is configured to receive refrigerant from the condenser when a first control valve is open and transfer heat from air passing the first evaporator to the refrigerant within the first evaporator. A first blower is configured to blow air across the first evaporator to a first section of a cabin of the vehicle. A second evaporator is configured to receive refrigerant from the condenser when a second control valve is open and transfer heat from air passing the second evaporator to the refrigerant within the second evaporator. A second blower is configured to blow air across the second evaporator to a second section of the cabin of the vehicle.

A refrigeration cycle including at least one outdoor unit including a plurality of compressors and indoor units each placed in indoor spaces comprises a plurality of compressors for supplying refrigerant to indoor units; and a controller for controlling cooperatively a plurality of the compressors in the outdoor unit to provide a capacity for air-conditioning in the indoor spaces through the indoor units, wherein the controller controls operation of the compressors so as to minimize a cost including start/stop of each compressor by prediction of an air-conditioning requirement in a next time chunk.

In an air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, high efficiency is achieved. The motor rotation rate of a compressor (100) can be changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved. In addition, an electrolytic capacitor is not required on an output side of a rectifier circuit (21), and thus an increase in the size and cost of the circuit is suppressed.

Embodiments of the present disclosure relate to a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system that includes a variable speed drive configured to provide power to a motor that drives a compressor of the HVAC&R system and a silicon carbide transistor of the variable speed drive, where the silicon carbide transistor is configured to adjust a voltage, or a frequency, or both of power flowing through the variable speed drive.

An air conditioning system of a vehicle having an internal combustion engine includes a condenser configured to receive refrigerant output by an electric compressor and transfer heat from the refrigerant within the condenser to air passing the condenser. A first evaporator is configured to receive refrigerant from the condenser when a first control valve is open and transfer heat from air passing the first evaporator to the refrigerant within the first evaporator. A first blower is configured to blow air across the first evaporator to a first section of a cabin of the vehicle. A second evaporator is configured to receive refrigerant from the condenser when a second control valve is open and transfer heat from air passing the second evaporator to the refrigerant within the second evaporator. A second blower is configured to blow air across the second evaporator to a second section of the cabin of the vehicle.

The present invention quickly stops rotation of an electric compressor while preventing damage to switching elements. An electric compressor 1 comprises a motor drive circuit 52 having multiple switching elements IGBT Q1 to Q6, a control unit 53 that controls driving of the multiple switching elements IGBT Q1 to Q6 and drives a motor 4, and a current detection unit 54 that detects a current flowing through the motor drive circuit 52. The control unit 53 performs stop control that stops rotation of the compression mechanism 3 by performing braking control that controls drive of predetermined switching elements IGBT (Q2, Q4, Q6 and the like) among the multiple switching elements IGBT Q1 to Q6. In the brake control, when the detected current value I is lower than the first threshold I.sub.1, the control unit 53 adjusts the drive pattern of the predetermined switching elements IGBT (Q2, Q4, Q6 and the like) in order to prevent the detected current value I from exceeding the second threshold I.sub.2 that is lower than the first threshold I.sub.1.