Design of Two-Phase 4/6 Switched Reluctance Motor for Bidirectional Starting in Washing Machine Application

In this article, design modification of stator poles of conventional two-phase switched reluctance motor is proposed to achieve self-start in both directions of rotation. Stator poles are slanted in a particular direction at the pole tips. This creates a range of rotor positions where torque polarity is the same for both phases, so starting torque is available. A unique excitation scheme is also proposed to run the motor in a particular direction from any initial position. The sequence in which the two phases are excited and the duration of their first excitation decides the direction of continuous rotation. Washing machine is selected as a potential application of the proposed work. Design parameters such as input voltage, rated current, and torque-speed characteristics are investigated to suit top-load washing machines. Simulations are carried out in finite element analysis software. Relation between the slant angle of the stator pole tip and minimum starting torque is analyzed through parametric simulations. Experiments are performed on a prototype two-phase switched reluctance motor. An incremental encoder is used as a position sensor. The initial position is not known, but self-starting in both directions of rotation is achieved with the proposed excitation scheme.