Sensorless BLDC Motor Ceiling Fan with an Isolated S4 BL PFC Converter

Here, a single switch and single stage boost-Luo (S⁴ BL) PFC (Power Factor Correction) converter is used with a DC link voltage of 48V to drive the sensorless brushless direct current (BLDC) motor ceiling fan. The main aim of this paper is to produce the retrofit solution for a ceiling fan without sensor with improved efficiency and power quality. This paper presents a new PFC converter for the sensorless BLDC motor ceiling fan with consideration of lower drain to source voltage across the switch. This PFC converter is designed in discontinuous inductor current mode (DCIM). The ceiling fan topology consists of a S⁴ BL PFC converter followed by a voltage source inverter (VSI) fed permanent magnet brushless direct current (PMBLDC) motor. To avoid the DC link voltage sensing, an auxiliary winding voltage is used to take care of an input voltage variation and it is also used to control the speed of the BLDC motor ceiling fan. The fundamental switching frequency is used to switch the VSI, to reduce the switching losses in it. Performance of a ceiling fan system is simulated in MATLAB to validate the design.