A Magnetic Continuously Variable Transmission Device

This paper describes a continuously variable transmission device, in which torque transmission and variable gear ratio is achieved by magnetic means. It consists of a stator which accommodates a 3-phase winding, and three concentric rotors: control rotor, input and output rotors. The control rotor has
p
_c
number of pole-pairs on the outer surfaces and
p
_l
number of pole-pairs of permanent magnets on its inner surface. The magnets on the outer surface of the control rotor interact with the currents in the 3-phase stator winding to produce torque in the same way as conventional brushless permanent magnet (PM) machines. The magnets on the inner surface of the control rotor interact with the input and output rotors to produce magnetic gearing action. It has been shown that by controlling the speed of the control rotor, the gear ratio between the output rotor and input rotor can be varied.