Abstract
Rotor vibration control during start-up, acceleration and deceleration phases are one of the key problems besides stable levitation, in high-speed applications of bearing less switched reluctance motor (BSRM) [1-3]. Global sliding mode controller (GSMC) is proposed to control the speed and position of BSRM. Sensor less operation is achieved with sliding mode observer. Rotor displacement tracking error functions were used in the sliding mode switching functions. New sliding mode displacement control and speed tracking equations obtained using extra exponential fast decaying nonlinear function and conventional linear sliding mode switching. Simulation is carried on hybrid 12/14 BSRM with the proposed controller and observer. 12 stator poles and 14 rotor poles were selected. Pole arc was 25.71. FEM analysis showed Torque pole arc was 12.85. Air gap length was 0.25 - 0.5 mm. Stator diameters -112/60.2, stator yoke thickness 7.7 mm, shaft diameter of 18 mm, coil width of 4 mm, rotor pole arc of 12.85, axial stack length of 40 mm, rotor yoke thickness of 9.7 mm-were the major design parameters. FEM of motor parameters under different loads for speed, torque load, switching angle, voltage, phase resistance and moment of inertia was performed. Separated single winding, wide suspending force region, higher power density, natural decoupling of torque from suspending force, low magnetic motive force, low core cost of hybrid 12/14 BSRM makes it ideal as motor for total artificial heart as destination therapy.
Keywords: Bearing Less Switched Reluctance Motor (BSRM); Global Sliding Mode Controller (GSMC); FEM Analysis; Destination Therapy (DT)