The invention discloses a capacity-control type double-cylinder
rotary compressor and a control method thereof. The capacity-control type double-cylinder
rotary compressor comprises a seal shell, wherein the
internal pressure of the seal shell is a high-pressure side pressure, and a motor
assembly and a compression
assembly connected with the motor
assembly are arranged in the shell; the compression assembly comprises a first cylinder, a second cylinder, an intermediate plate, a
crankshaft, a first
piston, a second
piston, a first
slip sheet, a second
slip sheet, a first
slip sheet cavity, a second slip sheet cavity, a
main bearing and an auxiliary bearing, wherein the
crankshaft is connected with the motor assembly; the first
piston and the second piston are connected with the
crankshaft to carry out eccentric rotation, and respectively arranged in a first cylinder compression chamber and a second cylinder compression chamber; the first slip sheet cavity and the second slip sheet cavity are respectively used for accommodating the back side end of the slip sheet; the
main bearing and the auxiliary bearing are used for supporting the crankshaft; and the double-cylinder
rotary compressor is provided with a gas
refrigerant injection device which injects gas refrigerants into the second cylinder compression chamber and is also provided with a
volume control device which switches the pressure of the second cylinder compression chamber between the high-pressure side pressure and the low-pressure side pressure. The capacity-control type double-cylinder rotary compressor has the advantages that the efficiency is improved effectively, and the EER (energy efficiency ratio) is high.