A reduced sensor PFC BL-Zeta converter based VSI fed BLDC motor drive

Abstract

This papers aims at the design of BL-Zeta (bridgeless Zeta) converter fed BLDC (Brushless DC) motor drive. A single voltage sensor is used for achieving PFC (Power Factor Correction) and DC link voltage control. Unlike the conventional approach of using a PWM (Pulse Width Modulation) switching of VSI (Voltage Source Inverter), a new approach of speed control is used to control the voltage at the DC link of VSI. A fundamental frequency switching is used for electronic commutation of BLDC motor for achieving reduced switching losses in the VSI. A voltage follower approach is employed for DC link voltage control in BL-Zeta converter operating in DCM (Discontinuous Conduction Mode). Moreover, the conduction losses in the DBR (Diode Bridge Rectifier) are also eliminated in a bridgeless topology of Zeta converter. A satisfactory performance of proposed drive is achieved for a wide range of speed control of BLDC motor and varying supply voltage to study the behaviour of proposed drive in practical supply conditions. Switches stresses are also analyzed for their selection and heat sink design. The power quality indices at AC mains obtained are found within the recommended limits by International power quality standards such as IEC 61000-3-2.