Brushless Wound Rotor Vernier Motor Using Single-Phase Additional Winding on Stator for Variable Speed Applications

This paper introduces a topology for achieving the brushless operation of a wound rotor vernier motor using a single-phase additional winding on the stator, specifically designed for variable-speed applications e.g., washing machines. In the proposed topology, the stator winding consists of two sets: a four-pole three-phase main winding and an additional two-pole single-phase winding. On the other hand, the rotor contains a 44-pole field winding to generate the vernier effect, and a two-pole excitation winding for induction. The main winding of the stator produces the fundamental component of MMF, while the additional winding generates the subharmonics component of MMF to induce a current in the excitation winding of the rotor. The excitation winding is connected to a rotating rectifier to supply direct current to the rotor’s field winding. The field interaction of the main and field winding is responsible for the production of torque. The presence of a subharmonic component of MMF in the air gap is confirmed through Fourier analysis of MMF obtained from the winding function. Moreover, the brushless operation of the proposed topology is validated using 2D finite element analysis (FEM) for variable speed application.