Sensorless Integrated AC–DC Power-Factor Correction (PFC) Converter for BLDCM-CF

The existing brushless direct current motor ceiling-fan (BLDCM-CF) has the demerits of high total harmonics distortion (THD) in the supply current, poor power-factor (PPF), slightly high-power consumption, and a high cost. It limits its use in household and industrial applications. This article presents the sensorless integrated ac–dc power factor correction (PFC) converter for BLDCM-CF with a high step-down gain (SDG) and reduced switch-stress to overcome the power quality problems. Its auxiliary-winding voltage is used as feedback to simplify the control. PFC converter is designed in discontinuous inductor current mode (DICM) with a wide change in dc-link-voltage (15–48 V) for an inherent PFC operation. The ceiling-fan (CF) speed is controlled by utilizing the voltage-speed linearity of the brushless direct current motor (BLDCM) with commutation control of inverter switches to get minimum switching losses. For the sensorless operation of BLDCM, the back EMF method is used to detect the actual rotor position. A laboratory prototype is developed to validate its design and show the presented CF has enhanced performance. Its current THD-1.46% with PF of 0.99885, and it meets IEC-standard 61000-3-2.