An adjustable speed PFC bridgeless-SEPIC fed brushless DC motor drive

This paper presents a bridgeless-single ended primary inductance converter (BL-SEPIC) fed brushless DC (BLDC) motor drive for low power household applications. The speed of the BLDC motor is controlled by adjusting the DC link voltage of the VSI feeding a BLDC motor. The VSI feeding BLDC motor is used for achieving an electronic commutation of the BLDC motor and operates in a low frequency switching for reduced switching losses in it. A bridgeless configuration of SEPIC is proposed which offers lower conduction losses due to the elimination of diode bridge rectifier (DBR) at the front end. A PFC based BL-SEPIC is designed to operate in a discontinuous inductor current mode (DICM) for achieving an inherent power factor correction at AC mains using a single voltage sensor. The performance of the proposed drive is validated with experimental results obtained on a developed prototype. An improved power quality is achieved at the AC mains for all conditions and the obtained power quality indices are achieved within the limits of international power quality standard IEC 61000-3-2.