A system includes a compressor having a shell housing a compression mechanism driven by an electric motor in an on state and not driven by the electric motor in an off state. The system also includes a variable frequency drive that drives the electric motor in the on state by varying a frequency of a voltage delivered to the electric motor and that supplies electric current to a stator of the electric motor in the off state to heat the compressor.

Disclosed are an inverter circuit, and air conditioner and refrigerator using the same. The inverter circuit includes a rectifier configured to rectify an input Alternating-Current (AC) voltage into a Direct-Current (DC) voltage; a smoothing portion configured to smoothen the DC voltage output from the rectifier; an inverter connected to a load, and configured to convert the DC voltage smoothened by the smoothing portion into an AC voltage, and to output the AC voltage to the load; and a suppressor installed between the rectifier and the smoothing portion, and configured to suppress an overvoltage or overcurrent of a DC link to which the DC voltage from the smoothing portion is applied.

A compressor driving apparatus and an air conditioner including the same, whereby the compressor driving apparatus includes a capacitor connected to a DC terminal, an inverter, including a plurality of three-phase switching devices, to convert DC power from the capacitor into AC power to drive a compressor motor, an output current detector to detect output current flowing in the motor, and a controller to output a switching control signal for controlling the inverter based on the output current, wherein the controller performs control such that some of the three-phase switching devices in the inverter are turned on or off in a compressor preheating mode.

A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.

Feedwater to be supplied to a feedwater tank via a feedwater path is passed through a waste heat recovery heat exchanger, a supercooler, and a condenser in sequence. A heat source fluid such as heat source water is passed through an evaporator and the waste heat recovery heat exchanger in sequence. The waste heat recovery heat exchanger is an indirect heat exchanger between the feedwater supplied to the feedwater tank via the feedwater path and the heat source fluid having passed through the evaporator. The supercooler is an indirect heat exchanger between the feedwater supplied to the feedwater tank via the feedwater path and a refrigerant supplied from the condenser to an expansion valve.

A compressor of a refrigeration appliance includes a motor, in particular a BLDC motor, and a controller for stopping the motor. The controller is configured to slow down the motor rotating in a first rotating direction until it comes to a standstill and to subsequently position the rotor relative to the stator, in a second rotating direction with a predetermined torque. A method for stopping a compressor of a refrigeration appliance is also provided.

The present invention relates to the fields of power electronics and electric motors, and describes a system for correcting harmonic content in power systems. The invention solves the space and weight problem, associated with the core of an inductor for correcting harmonic content, also providing performance advantages of electric motors, such as higher available voltage at maximum load and higher rotational speed at maximum load. The invention is particularly useful in refrigeration compressors.

A freezing device including a compressor that compresses sucked refrigerant using a compression mechanism and discharges compressed refrigerant includes a compressor, an inverter, and a controller. The compressor includes a motor, a low pressure unit, a compression space, a high pressure unit, a communication flow path, and a flow control valve. The inverter drives or stops the motor. The controller controls the inverter and the flow control valve. The controller performs, in stop control in which an operation of the compressor is stopped, braking control in which driving of the compression mechanism is prevented or suppressed, and pressure equalization control in which pressure in the high pressure unit is equalized with pressure in the low pressure unit.

An electric motor system is described. The electric motor system includes a drive circuit including an inverter configured to supply variable frequency current and a contactor configured to supply line frequency current. The electric motor system also includes an electric motor coupled to the drive circuit wherein the electric motor is communicatively coupled to a controller. The controller is configured to control the inverter to supply variable frequency current to the electric motor, thereby operating the electric motor at a motor speed, and determine, based upon at least one input parameter, a maximum potential motor speed the inverter can achieve. The controller is also configured to receive a command to operate the electric motor at line frequency current and control the drive circuit to transition from supplying variably frequency current to supplying line frequency current before the maximum potential motor speed the inverter can achieve is reached.

An integrated cooling system and method for a transportation refrigeration system including: a heat rejection heat exchanger; a subcooler comprising a plurality of flow paths, the subcooler operably coupled to the first rejection heat exchanger; and a heat transfer apparatus comprising a first portion and a second portion, wherein the first portion is operably coupled to at least one of the plurality of flow paths and the second portion is operably coupled to a heat source.