Adual-rotor permanent magnet induction motor (DRPMIM) is an induction motor having two rotors within the same motor housing. This rotor arrangement can increase power density, efficiency, and reduce cogging torque.[1][2]
Stator on the outside
In one arrangement, the motor has an ordinary induction motor stator. A squirrel-cage rotor connected to the output shaft rotates within the stator at slightly less than the rotating field from the stator. Within the squirrel-cage rotor is a freely rotating permanent magnet rotor, which is locked in with rotating field from the stator. The effect of the inner rotor is to reenforce the field from the stator.[1]
Stator between rotors
One rotor in on the inside and one rotor is on the outside
In another arrangement, one rotor is inside the stator with a second rotor on the outside of the stator.[2][3]
Applications
Because of their greater power, density dual-rotor permanent magnet induction motors are being considered for use in electric vehicles.