A NOVEL SEVEN LEVEL SERIES CONNECTED MLI TOPOLOGY FED BLDC DRIVE SYSTEM FOR INDUSTRIAL APPLICATIONS

Recently, developments in power electronics and semiconductor technology have lead improvements in power electronic systems. Pulse Width Modulation variable speed drives are increasingly applied in many new industrial applications that require superior performance. Hence, different circuit configurations namely multilevel inverters have become popular and considerable interest by researcher are given on them. The torque produced by the Brushless DC (BLDC) motors with trapezoidal back Electromotive force (BEMF) is constant under ideal condition. However in practice the torque ripple appears on the delivered output torque. Smoothness of variable speed drive operation is critical due to this torque ripple. The brushless DC motors uses power electronic switches for the commutation purpose, it creates the harmonics in armature current regulate by increased number of levels by switching topology. This paper proposes a 7-level Cascaded H-Bridge Multilevel Inverter fed BLDC drive with current controller used to reduce the torque ripple and the harmonics. The simulation results based on Matlab/Simulink are discussed in detail in this paper