A regulator assembly, comprising a vaned diffuser, a motor, a driving gear engaged with a driven gear, the driven gear having rectangle-shaped through holes thereon, the rectangle-shaped through holes disposed and extending along an axis of the driven gear, and a regulating mechanism including a regulator, a supporting member, wherein the regulator is sleeved on the supporting member, and wherein the vaned diffuser is fixed on the supporting member, and regulator sliding members fixed to the regulator through the rectangle-shaped through holes of the driven gear, whereby the motor is configured to drive the driving gear to rotate, the driving gear is configured to drive the driven gear to rotate, the driven gear is configured to push the regulator sliding members to move, and the regulator sliding members are configured to drive the regulator to rotate relative to the vaned diffuser, thus driving the regulator to move along its axis.