Rotary-Reciprocating Movement Switched-Reluctance Machines With Consequent Axially Shifted Poles

A new switched-reluctance machine (SRM) topology with combined rotary and reciprocating rectilinear movement is introduced in this paper. The topology of this machine is based on the conventional radial-flux SRM with a modified rotor structure. Unlike the other rotary-translational electromechanical systems which have separate units, one for rotary motion and another for translational reciprocating motion, the proposed machine achieves combined rotary-reciprocating (RR) movement with just one set of stator coils around each pole identical to the conventional SRM. By exciting each pole of the stator, both radial and axial magnetic flux will be produced in the air gap of the machine. As a result, the electromagnetic reluctance torque around the axis of the rotation and the reluctance force along the axis of translational movement are produced. Details of the rotor structure and machine operation are presented. Magnetic equivalent circuit (MEC) analytical equations are derived for four operational points within the RR motion cycle. Finite-element analysis (FEA) is utilized to validate the analytical MEC equations. The output performance profiles are simulated for two example machines using static 3-D FEA to investigate the impact of the axial displacement of the consequent poles. In addition, a sensitivity analysis is carried out to investigate the impact of the rotor pole angle on the torque and force production of the machine. The dynamic behavior of the proposed structure is analyzed and discussed for two displacements of the consequent axially shifted poles.