A compressor fault diagnostic apparatus including a current sensing unit to sense a current flowing through a motor of the compressor, a fault diagnostic unit to determine whether or not the motor performs a reverse rotation based on the current flowing through the motor, and a cut-off unit to remove power based on a determination of the fault diagnostic unit.

An air-conditioning apparatus includes a refrigerant circuit including a compressor, an indoor-side heat exchanger, and an outdoor-side heat exchanger; a drive circuit configured to drive an electric motor; a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state; and a controller configured to perform defrosting operation for removing frost formed on the outdoor-side heat exchanger and cause the connection switching device to switch connection. In performing the defrosting operation with the stator windings being in the second connection state, the controller causes the connection switching device to switch the connection of the stator windings from the second connection state to the first connection state.

A method and system for dynamic power allocation in a transport refrigeration system (TRS) is provided. The method includes a TRS power source operating in an operational state. The method also includes monitoring an amount of current being drawn from one or more generator powered components of the TRS. Also, the method includes calculating, via a TRS controller of the TRS, a maximum available horsepower amount based on the amount of current being drawn from the one or more generator powered components. Further, the method includes controlling, via the TRS controller, an amount of horsepower directed to a compressor of the TRS based on the maximum available horsepower amount.

Embodiments of the present invention provide a method for controlling compressor braking, a frequency converter and a variable speed compressor. The method includes steps of: determining to brake a compressor, wherein a brake circuit includes three switching units and the three switching units are respectively electrically connected to three phases of windings of a motor of the compressor; actuating two of the three switching units to short-circuit two phases of windings of the motor. The two phases of windings of the motor are short-circuited by controlling the three switching units to generate braking torque, such that the compressor is braked without introducing a DC voltage, and thus the braking energy consumption is reduced. Besides, by turning on only two switches at a time, the switching abrasion is reduced, and the overall service life of the three switching units is effectively improved.

A condenser includes a shell having a vapor refrigerant inlet, a first tube bundle and a liquid refrigerant outlet. A second tube bundle is positioned in a subcooler component. The subcooler component has a center channel and at least two outer channels and conforms to the shell.

An air-conditioning apparatus including a compressor incorporating an electric motor; a temperature sensor configured to detect indoor temperature; a drive circuit configured to drive the electric motor; a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state; and a controller configured to enter thermo-off when the indoor temperature reaches a target temperature or a correction temperature set based on the target temperature and cause the connection switching device to switch connection, the thermo-off being entered by stopping the compressor via the drive circuit. When a thermo-off count reaches a reference count with the electric motor being in the first connection state, the controller causes the connection switching device to switch connection from the first connection state to the second connection state.

A portable refrigerator includes a main housing, a refrigerator cover, a cooling mechanism, a rechargeable battery pack and a control unit. The cooling mechanism includes heat exchanging tubes, a compressor, an evaporator and a condenser connected to the evaporator and the compressor. The rechargeable battery pack is detachably attached on a power compartment of the main housing. The control unit is supported in the main housing and electrically connected to the rechargeable battery pack and the cooling mechanism for centrally controlling an operation of the cooling mechanism. A predetermined amount of refrigerant is arranged to controllably pass through the heat exchanging tubes, the condenser, the evaporator and the compressor for extracting heat from the accommodating cavity.

A portable refrigerator includes a main housing, a refrigerator cover, a cooling mechanism, a rechargeable battery pack and a control unit. The cooling mechanism includes heat exchanging tubes, a compressor, an evaporator and a condenser connected to the evaporator and the compressor. The rechargeable battery pack is detachably attached on a power compartment of the main housing. The control unit is supported in the main housing and electrically connected to the rechargeable battery pack and the cooling mechanism for centrally controlling an operation of the cooling mechanism. A predetermined amount of refrigerant is arranged to controllably pass through the heat exchanging tubes, the condenser, the evaporator and the compressor for extracting heat from the accommodating cavity.

A vector control system is used to control a vapor compression circuit that includes a compressor motor. The vector control system is used to monitor the vapor compression circuit and adjust the speed of one or more motors within the vapor compression circuit to increase efficiency of the system by taking into account the torque forces placed on the compressor motor.

This method for controlling asynchronous electrical motors of a compressor system, comprises: receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.