A Unity Power Factor Bridgeless Isolated Cuk Converter-Fed Brushless DC Motor Drive

This paper presents a power factor correction (PFC)-based bridgeless isolated Cuk converter-fed brushless dc (BLDC) motor drive. A variable dc link voltage of the voltage source inverter (VSI) feeding the BLDC motor is used for its 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 drive is controlled using a single voltage sensor to develop a cost-effective solution. The proposed drive is implemented to achieve a unity power factor at the ac mains for a wide range of speed control and supply voltages. An improved power quality is achieved at ac mains with power quality indices within the limits of the IEC 61000-3-2 standard.