Abstract:
Now bearingless motors that are being studied are all to combine the magnetic field together with motor and suspension bearing. The two magnetic fields are mixed, on the one hand, magnetic saturation is easily caused to affect bearing capacity and steady suspension of motor; on the other hand, a very strong nonlinear coupling between electromagnetism torque and radial suspension force is generated, whereas, it is very complex to realize decoupling control. In combination with the advantages of magnetic suspension bearing and direct current(DC) motor without brush, an innovative six-freedom DC motor without bearing and brush was put forward.. Through studying its suspension principle, moving principle, the accurate mathematics model was established when rotor is eccentric and when PWM adjustment speed is used. Simulation results prove the reasonability of this kind of motor structure. The major characteristics of the motor are as follows: it has high bearing capacity, and the control between electromagnetism torque and radial suspension force is mutually independent, in no need of complex nonlinear decoupling control.