Reduction of common mode voltage for three-level inverter using novel switching sequences

Abstract

This paper proposes three Novel switching sequences 712, 7121 and 1712 for a NPC three level inverter for reducing the Common mode voltages. In switching sequences reported recently for three-level inverter, given by 0127, 0121 and 1012, the current THD is less for 0121 at higher frequencies and also less for 0127 for middle frequencies compared to remaining possible sequences. But the common mode voltage is more for these sequences. The proposed sequences maintain the same current THD as that of recently reported sequences and also reduce the Common mode voltage. To check the validity of the proposed sequences, simulations are done using MATLAB/Simulink for open loop v/f control of three-level inverter fed Induction motor.