Minimization of Cogging Torque and Current Control in Brushless DC Machine by Co-simulation Process

This paper deals with a comprehensive study on reducing cogging torque generated in Brushless DC motor drives (BLDC). In such drives, cogging torque suppression techniques that are practically effective in low speed as well as high speed regions are scarcely found in literature. A well-known skewing technique is adapted in the stator slots to reduce the cogging torque using CAD package Magnet 6.1.1.This paper addresses also the problem of phase current control using 3-phase bridge inverter. By the co-simulation interfacing of the PSIM 6.1 and Magnet software, the designed machine is controlled. This is based on a strategy that the current slopes of the incoming and outgoing phases during the commutation interval can be equalized by a proper duty-ratio control scheme. The proposed control method accomplishes suppression of spikes and dips super imposed on the current and torque responses during the commutation intervals of the inverter. The effectiveness of proposed control method is verified through simulation methods.