Integral linear cryogenic Stirling refrigerator comprised of the free piston positive displacement pressure wave generator, the moving assembly of which is connected to the free piston displacer by the dynamic “spring-mass-spring” mechanical phase shifter the mechanical properties of which (spring rates and weight) are selected to provide a predetermined phase lag of motion of the displacer piston relative to the moving assembly of pressure wave generator.

A cryocooler includes a compressor, an expander that includes a motor and is driven by the motor, an inverter that controls an operation frequency of the motor, a high pressure line that connects the compressor to the expander such that a working gas is supplied from the compressor to the expander, a low pressure line that connects the compressor to the expander such that a working gas is collected from the expander to the compressor, a pressure measurement unit that is configured to measure pressures of the high pressure line and the low pressure line or to measure a differential pressure between the high pressure line and the low pressure line, and a controller that compares the differential pressure to a target pressure and controls the inverter such that the operation frequency of the motor is increased when the differential pressure exceeds the target pressure.

Cryogenic refrigeration device comprising a working circuit intended to cool a working fluid circulating in the said circuit, the working circuit comprising, arranged in series in a loop: a compression portion, a cooling portion, a portion with valve(s), an expansion portion and a reheating portion, in order to subject the working fluid to a recuperative working cycle comprising compression, then cooling, then expansion and then reheating to prepare for a new cycle, wherein the compression portion comprises at least one compressor having a linear piston driven by a linear motor, the expansion proportion comprises at least one expander with a linear piston, the portion with valve(s) comprises at least one regulating valve linearly actuated by a linear motor and controlled in order to supply or extract the working fluid from the at least one expansion piston.

A cryogenic cooler includes a housing, and first, second, and third actuators. The first actuator includes at least one first voice coil and at least one first magnetic circuit, the at least one first voice coil of the first actuator configured to drive a compressor piston, the first actuator causing vibrations to the housing when driving the compressor piston. The second actuator includes at least one second voice coil and at least one second magnetic circuit, the at least one second voice coil of the second actuator configured to reduce the vibrations to the housing caused by driving the compressor piston. The third actuator includes at least one third voice coil and at least one third magnetic circuit, the third actuator configured to drive a displacer piston. The compressor piston, balance mechanism, and displacer piston are concentrically formed within the cryogenic cooler.

A free piston Stirling refrigerator of the present invention has a cylinder provided inside a casing; a piston and a displacer that are provided in a way such that they are capable of reciprocating inside the cylinder; a linear motor for reciprocating the piston; and a control unit for controlling the operation of the linear motor. Particularly, the control unit has an inverter circuit for generating an alternating current with a given frequency and then supplying the alternating current to the linear motor; a current detection circuit for detecting the current outputted from the inverter circuit; and a control circuit for controlling the output from the inverter circuit based on a turbulence in the current detected by the current detection circuit. Thus, collisions between the piston and the displacer (i.e. hitting) can be restricted through an inexpensive configuration and a simple control.

A cryocooler includes a compressor, an expander that includes a motor and is driven by the motor, an inverter that controls an operation frequency of the motor, a high pressure line that connects the compressor to the expander such that a working gas is supplied from the compressor to the expander, a low pressure line that connects the compressor to the expander such that a working gas is collected from the expander to the compressor, a pressure measurement unit that is configured to measure pressures of the high pressure line and the low pressure line or to measure a differential pressure between the high pressure line and the low pressure line, and a controller that compares the differential pressure to a target pressure and controls the inverter such that the operation frequency of the motor is increased when the differential pressure exceeds the target pressure.

A linear compressor includes: a shell; a cylinder provided inside the shell; a frame coupled to an outer side of the cylinder; a piston configured to reciprocate in an axial direction; a motor that supplies power to the piston; and a spring mechanism coupled to the piston. The spring mechanism includes: a support connected to the piston and including a spring support unit having one or more insertion holes; a first coupling protrusion that extends from the rear side of the spring support unit along the edge of the insertion hole; a support cap inserted into the insertion hole and including a second coupling protrusion protruding from the front side of the spring support unit; a first resonant spring inserted into the outer circumferential surface of the second coupling protrusion; and a second resonant spring inserted into the outer circumferential surface of the first coupling protrusion.

The present disclosure relates to a linear compressor. The linear compressor according to an aspect of the present disclosure includes a shell, a cylinder, a piston, and a muffler. Also, an internal space in which at least a portion of the muffler is inserted is formed in the piston, and the muffler is disposed in contact with the inner wall of the piston forming the internal space.

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.

Integral linear cryogenic Stirling refrigerator comprised of the free piston positive displacement pressure wave generator, the moving assembly of which is connected to the free piston displacer by the dynamic spring-mass-spring mechanical phase shifter the mechanical properties of which (spring rates and weight) are selected to provide a predetermined phase lag of motion of the displacer piston relative to the moving assembly of pressure wave generator.