A compressor may include first and second compression members, first and second bearing assemblies, a sensor, and processing circuitry. The second compression member cooperates with the first compression member to define a compression pocket. The first and second bearing assemblies rotatably support the first and second compression members, respectively. The first bearing assembly may include a bearing rotor and a bearing stator. The bearing stator may surround the bearing rotor and may include poles each having a winding. The sensor may measure a radial position of the bearing rotor relative to the bearing stator. The processing circuitry may be in communication with the sensor and may control electrical current supplied to the windings based on the radial position measured by the sensor to adjust the radial position of the bearing rotor relative to the bearing stator.

A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

A compressor may include a shell, first and second scrolls, a seal assembly, a modulation control chamber, and a modulation control valve. The first scroll may include a first end plate having a biasing passage extending therethrough. The seal assembly may isolate a discharge pressure region from a suction pressure region. The seal assembly and the first scroll may define an axial biasing chamber therebetween that communicates with the axial biasing chamber and a first pocket between the first and second scrolls. The modulation control chamber may be fluidly coupled with the biasing chamber by a first passage. The modulation control valve may be fluidly coupled with the modulation control chamber by a second passage and movable between a first position allowing communication between the second passage and the suction pressure region and a second position restricting communication between the second passage and the suction pressure region.

A compressor may include a shell, first and second scrolls, a seal assembly, a modulation control chamber, and a modulation control valve. The first scroll may include a first end plate having a biasing passage extending therethrough. The seal assembly may isolate a discharge pressure region from a suction pressure region. The seal assembly and the first scroll may define an axial biasing chamber therebetween that communicates with the axial biasing chamber and a first pocket between the first and second scrolls. The modulation control chamber may be fluidly coupled with the biasing chamber by a first passage. The modulation control valve may be fluidly coupled with the modulation control chamber by a second passage and movable between a first position allowing communication between the second passage and the suction pressure region and a second position restricting communication between the second passage and the suction pressure region.

A scroll compressor includes a casing accommodating a rotary shaft and a driving unit, a first scroll making an orbiting movement by the rotary shaft, a second scroll engaged with the first scroll to form a compression chamber and having a bypass hole bypassing a refrigerant sucked into the compression chamber to an internal space of the casing, and a back-pressure chamber assembly pressing the second scroll toward the first scroll, wherein the back-pressure chamber assembly includes: a back-pressure space, a first valve unit allowing the bypass hole and the internal space of the casing to selectively communicate with each other, and a second valve unit opened and closed to selectively supply the refrigerant of the back-pressure space to the first valve unit to operate the first valve unit, and positioned to be fixed to the casing.

A scroll compressor includes a casing accommodating a rotary shaft and a driving unit, a first scroll making an orbiting movement by the rotary shaft, a second scroll engaged with the first scroll to form a compression chamber and having a bypass hole bypassing a refrigerant sucked into the compression chamber to an internal space of the casing, and a back-pressure chamber assembly pressing the second scroll toward the first scroll, wherein the back-pressure chamber assembly includes: a back-pressure space, a first valve unit allowing the bypass hole and the internal space of the casing to selectively communicate with each other, and a second valve unit opened and closed to selectively supply the refrigerant of the back-pressure space to the first valve unit to operate the first valve unit, and positioned to be fixed to the casing.

A compressor may include a shell assembly, a non-orbiting scroll, and an orbiting scroll. The shell assembly may define a discharge chamber. The non-orbiting scroll includes a first end plate and a first spiral wrap extending from the first end plate. The first end plate may include a variable-volume-ratio port. The orbiting scroll may be disposed within the discharge chamber. The orbiting scroll includes a second end plate and a second spiral wrap extending from the second end plate and cooperating with the first spiral wrap to define a plurality of fluid pockets therebetween. The second end plate may include a discharge passage in communication with a radially innermost one of the fluid pockets and the discharge chamber. The variable-volume-ratio port may be disposed radially outward relative to the discharge passage and may be in selective communication with the radially innermost one of the fluid pockets.

A compressor may include a shell assembly, a non-orbiting scroll, and an orbiting scroll. The shell assembly may define a discharge chamber. The non-orbiting scroll includes a first end plate and a first spiral wrap extending from the first end plate. The first end plate may include a variable-volume-ratio port. The orbiting scroll may be disposed within the discharge chamber. The orbiting scroll includes a second end plate and a second spiral wrap extending from the second end plate and cooperating with the first spiral wrap to define a plurality of fluid pockets therebetween. The second end plate may include a discharge passage in communication with a radially innermost one of the fluid pockets and the discharge chamber. The variable-volume-ratio port may be disposed radially outward relative to the discharge passage and may be in selective communication with the radially innermost one of the fluid pockets.

A scroll compressor comprises a partition plate, a compression mechanism, a capacity adjustment device and a sealing assembly. The sealing assembly isolates a back pressure chamber from a high-pressure space and low-pressure space. A first sealing portion is formed between the sealing assembly and the partition plate. The capacity adjustment device is provided with a variable pressure chamber and configured to establish or break the communication between a first compression chamber and the low pressure space by changing the pressure in the variable pressure chamber. According to the compressor, requirements for pressure in the back pressure chamber of the compressor in different load conditions can be balanced, the axial force on the compression mechanism can be reduced, the power consumption of the scroll compressor can be lowered, the system performance can be improved, and the manufacturing cost can be reduced.

Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.