Air injection enthalpy-increasing scroll compressor and refrigeration system

An enhanced vapor injection scroll compressor comprising:

• a compressor housing;
• a main frame in the compressor housing;
• a motor disposed below the main frame;
• a sub-frame disposed below the motor,
• wherein a high-pressure cavity is defined by a space between the motor and the main frame and a space between the motor and the sub-frame;
• an orbiting scroll on the main frame, wherein the orbiting scroll comprises an orbiting scroll end plate and an orbiting scroll wrap on a side end face of the orbiting scroll end plate away from the main frame, wherein a back pressure chamber is defined between the orbiting scroll end plate and the main frame;
• and
• a fixed scroll on a side of the orbiting scroll away from the main frame, wherein the fixed scroll comprises a fixed scroll end plate and a fixed scroll wrap on a side end face of the fixed scroll end plate adjacent to the main frame, wherein the fixed scroll wrap and the orbiting scroll wrap mesh with each other to form a plurality of crescent-shaped compression cavities that includes a first compression cavity and a second compression cavity,
• wherein one of the orbiting scroll and the fixed scroll is provided with a first medium pressure passage and the other one of the orbiting scroll and the fixed scroll is provided with a second medium pressure passage,
• wherein the first medium pressure passage is configured to operatively connect the first compression cavity of the plurality of compression cavities with the back pressure chamber as the orbiting scroll rotates relative to the fixed scroll, and
• wherein the second medium pressure passage is configured to operatively connect the second compression cavity of the plurality of compression cavities with the back pressure chamber as the orbiting scroll rotates relative to the fixed scroll.