Three Phase Improved Cascaded Multilevel Inverter Fed Induction Motor Drives For THD Reduction

This work focused on investigating closed loop model of improved cascaded multilevel inverter fed induction motor drives with active filter to reduce THD. Multilevel inverter emerged as a key factor in industrial drives to maintain speed and reduce THD for high power-medium voltage applications. Conventional inverter fed induction motor drives contain poor quality of voltage and current due to harmonic content which causes energy losses. To reduce THD content and improve power quality supply, a new topology of cascaded multilevel inverter is presented with minimum number of switches. It needed only 9 switches but conventional topology used 20 switches for the same 11 level output. Active filter used to reduce harmonic content. Eleven levels MLI with active filter is simulated with induction motor as load and harmonic spectrum is analyzed with and without filter.