Switched reluctance motor delivering constant torque from three phase sinusoidal voltages

摘要

The physical characteristics of a switched reluctance motor that is able to produce constant torque when driven by three phase sinusoidal voltages are disclosed. The main requirement is that the coil inductances have a sinusoidal variation of inductance as a function of rotor angle. The required angular variation of the inductance is achievable by selecting certain proportions of stator and rotor pole widths, and stacking the rotor laminates in a particular spiral pattern. The constant torque is possible only for certain specific values of the number of salient rotor and stator poles in a combination not previously used in switched reluctance motors. When the three coils are connected in standard “Y” connection and the junction is not grounded, but left floating, the voltage at the junction becomes a sensor for the mechanical speed and position of the rotor, since it will have an electrical frequency that is a multiple of the rotor angular frequency plus the input electrical frequency, and a phase relative to the applied voltages that uniquely determines the angular position of the rotor.