Because of the current commutation and the double salient pole structure of bearingless switched reluctance motors (BSRMs), the torque and suspension force have large ripples when traditional current control methods are used. According to the special structure of the double stator BSRM (DSBSRM), the direct decoupling of torque and suspension force is realized. Therefore, the DSBSRM can be controlled separately as a conventional 12/8 SRM and a four-poles active magnetic bearing. In order to achieve the suppression of the torque ripple and improve the robustness of speed, a direct torque control (DTC) strategy using second order sliding mode (SOSM) speed controller is proposed. In order to achieve the suppression of the suspension force ripple and rotor displacement chattering, a direct suspension force control (DSFC) strategy is proposed as well. Then the SOSM-DT/DSFC model is established by simulink. The results of simulation show that the torque ripple, suspension force ripple and rotor radial displacements of DSBSRM can be reduced respectively. Moreover, the proposed control strategy has better robustness and dynamic performance than traditional control strategy.
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