Power quality improvements in a zeta converter for brushless DC motor drives

This study deals with a reduced sensor configuration of a power factor correction (PFC) based zeta converter for brushless DC (BLDC) motor drive for low power applications. The speed of the BLDC motor is controlled by varying the dc-link voltage of the voltage source inverter (VSI) feeding BLDC motor drive. A low-frequency switching of the VSI is used for achieving the electronic commutation of BLDC motor for reduced switching losses. The PFC-based zeta converter is designed to operate in discontinuous inductor current mode; thus utilising a voltage follower approach which requires a single voltage sensor for dc-link voltage control and PFC operation. The proposed drive is designed to operate over a wide range of speed control with improved power quality at ac mains. The performance of the proposed drive is validated with experimental results obtained on a developed prototype of PFC converter.