Improved Power Quality Bridgeless Isolated Cuk Converter Fed BLDC Motor Drive

In this paper a new bridgeless isolated power factor correction (PFC)-based Cuk converter-fed brushless dc (BLDC) motor drive is introduced for power factor correction and reduction in total harmonic distortion of input current. Dc link voltage of the voltage source inverter (VSI) feeding the BLDC motor is varied for speed control. This allows the operation of VSI in fundamental frequency switching to achieve an electronic commutation of the BLDC motor for reduced switching losses. A bridgeless configuration of an isolated Cuk converter is derived for the elimination of the front-end diode bridge rectifier to reduce conduction losses in it. The proposed PFC-based bridgeless isolated Cuk converter is designed to operate in discontinuous inductor current mode to achieve an inherent PFC at the ac mains. The proposed system is simulated in MATLAB using both PI controller and fuzzy logic controller and implemented to achieve unity power factor at the ac mains for a wide range of speed control. An improved power quality is also achieved at ac mains with power quality indices within the limits of international standards.