The invention discloses a 660MW supercritical unit FCB control technology system, and belongs to the technical field of a vehicle speed reducer. The system has energy feedback auxiliary speed reduction and cooling functions and can convert rotation energy or thermal energy on a rotor into a part of cooling energy needed by cooling and a part of brake energy needed by transmission shaft speed reduction. The system comprises a micro controller, a stator, a rotor, a control mechanism and a transmission shaft; the stator comprises a clutch end cover, a stator drum equipped with an exciting coil, agearbox end cover and a transverse pipe which are fixedly connected in sequence from left to right; the rotor comprises a circular annular block and a number one bearing; a pipe cavity of the transverse pipe is movably formed in the transmission shaft in a sleeving manner; the right end of the transverse pipe is fixedly connected with the left end plane of the gearbox end cover; an inner hole ofthe number one bearing is tightened and fixedly connected with the outer wall of the transverse pipe; an inner ring of the circular annular block is tightened and fixed on the number one baring; and the control end of the exciting coil is connected with the micro controller.