Sensorless control using single current sensor with PFC assisted SRM drive for cost-effective domestic appliances

This paper presents a sensorless control designed for low to medium speed operation of an 8/6 pole switched reluctance motor (SRM) drive, utilizing only a single current and voltage sensor while ensuring grid-side power quality. It emphasizes a cost-effective solution suitable for low-power applications in both domestic and industrial appliances, employing SRM drive technology. In this, AC input is fed to Cuk converter that suppresses grid current total harmonic distortion (THD). Using symmetrical structural properties of SRM allows for a cost-friendly sensorless control approach. Position estimation for four-phase SRM is achieved by comparing two-position reference fluxes with running flux. In case of four-phase SRM, phases A and C are conducted sequentially, enabling a single voltage and current sensor to estimate flux for both phases. This method contrasts with lookup table-based rotor position estimation, requiring only two sets of position flux data, thus reducing memory usage, controller complexity, and speeding up response. A laboratory prototype of a four-phase 8/6 SRM is used to estimate rotor position in sensorless control. Finally, test results are used to validate effectiveness of presented PFC assisted sensorless control approach.