S⁴BL Power-Factor-Corrected Converter Powered Sensorless BLDC Motor Ceiling-Fan

Ceiling fans (CF) with brushless direct current motor (BLDCM) are available commercially. However, power-quality issues are present in an existing CF like high supply current harmonics distortion, poor power factor (PF), electromagnetic interferences (EMI), etc. Power quality and EMI issues are present due to high-frequency PWM control of an inverter. Moreover, cost of these fans is much high due to use of sensors. To fix these problems, a sensorless BLDCM-CF is presented. A change in output-voltage with single-switch and single-stage boost-Luo power factor corrected converter (S⁴BL-PFCC) is employed to acquire a controlled-speed. A variable voltage control has fundamental-frequency operation of an inverter, which shrinks-down switching-losses, eliminating current-sensors needed to sense current and improving CF-efficiency. Converter's discontinuous-conduction mode (DCM) design inherently offers PFC and minimizes size of components.  High-frequency transformer's auxiliary winding is utilized to eliminate a DC-link sensor, which reduces CF cost. Moreover, motor Hall-sensors are removed with sensorless-control of back-EMF, which removes filtering circuitry, required auxiliary supply and reduces CF's overall cost. PFCC-fed BLDCM drive is designed and modeled such that its performance is not affected under dynamic conditions. To verify CF’s design and simulated performance with a change in speed, a lab-based prototype is built. Presented CF exhibits excellent PQ indices and obeys standard-IEC61000-3-2.