A refrigeration cycle apparatus includes a refrigerant circuit, a controller, a bypass pipe, a refrigerant cooler, a second expansion device, and a controller temperature sensor. In a case where a temperature measured by the controller temperature sensor is lower than or equal to a set temperature in a state where an opening degree of the second expansion device is controlled to an instruction opening degree that is lower than or equal to a set opening degree, the controller is configured to perform foreign substance release control where the controller is configured to increase the opening degree of the second expansion device and then is configured to return the opening degree of the second expansion device to the instruction opening degree.

A system and method of controlling temperature of a medium by refrigerant vaporization, the system including a container, at least one a refrigerant reservoir having at least one reservoir section that includes a wall with an exterior surface structured to be thermally coupled with a volume of the medium in the container and to provide a volume of medium thermal coverage in the container, a vapor pressure apparatus to provide regulation of refrigerant vapor pressure in the at least one refrigerant reservoir, whereby the refrigerant reservoir forms a vapor space in each of the at least one reservoir section in response to receiving refrigerant and to the vapor pressure apparatus regulation of vapor pressure above the refrigerant to enable refrigerant vaporization at or near a selected temperature of the volume of medium in the container that is thermally coupled to the respective reservoir section.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

A driving device drives a motor having coils. The driving device includes a converter to generate a bus voltage, an inverter to convert the bus voltage to an AC voltage and supply the AC voltage to the coils, and a connection switching unit to switch a connection state of the coils. The bus voltage generated by the converter is switched in accordance with the connection state of the coils.

A method for controlling a linear compressor and a method for controlling a refrigerator are provided. The method for controlling a linear compressor may include measuring an ambient temperature, and when the measured ambient temperature is equal to or lower than a predetermined safety temperature, applying a safety current to a motor assembly for driving a piston. On the other hand, when the measured ambient temperature is higher than the predetermined safety temperature, a current lower than the safety current may be applied to the motor assembly.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

A system and method for flooded start control of a compressor for a refrigeration system are provided. A sensor generates sensed data corresponding to a condition of the refrigeration system. A control module is configured to operate the compressor in a flooded-start control mode including operating the compressor according to a cycle with a first time period during which the compressor is on and a second time period during which the compressor is off. The control module operates the compressor in an initial time period, without using the flooded-start control mode, with liquid refrigerant present in the compressor and monitors the sensed data from the sensor. The control module operates the compressor in the flooded start control mode after determining the first time period, the second time period, or a number of cycles, based on the sensed data monitored during the initial time period.

Methods and systems for detecting and correcting improper operation of a compressor in a refrigeration system and/or an HVAC system include a component level detection and prevention and a system level detection and prevention. The system level detection and prevention can be a backup or a confirmation of the component level detection and prevention. The component level detection and prevention can detect and prevent improper compressor operation within a predetermined time so that the compressor's operation period in an improper direction can be minimized, thereby minimizing wear and damage to the compressor.

Techniques are disclosed for systems and methods to reduce mechanical vibrations within a cryocooler/refrigeration system configured to provide cryogenic and/or general cooling of a device or sensor system. A cryocooler includes a motor driver controller configured to receive operational parameters and generate motor driver control signals and/or balancer system control signals based, at least in part, on the received operational parameters, and a motor driver configured to receive the control signals and generate drive signals to drive a motor and/or a balancer system of the cryocooler. The cryocooler includes a motorized and/or actively balanced expander configured to drive and/or balance motion of a displacer of the expander. The expander includes a magnet ring fixed to the displacer and a motor coil disposed within a cylinder head of the motorized and/or actively balanced expander.

An air conditioning system includes a main circuit having a multi-stage compressor, a condenser, a throttling element and an evaporator connected by pipelines; and a cooling branch, the inlet of which is connected to the main circuit between the condenser and the throttling element, and the outlet of which is connected to at least one of the first-stage suction port and the intermediate-stage suction port of the multi-stage compressor, wherein refrigerant from the cooling branch flows through the drive motor of the multi-stage compressor, and a regulating valve for controlling the opening of the cooling branch is provided on the cooling branch; and a control module that controls the opening of the regulating valve on the cooling branch based on the temperature of the outlet downstream of the drive motor on the cooling branch and the intermediate suction pressure of the intermediate-stage suction port of the multi-stage compressor.