[01] C. R. Balamurugan, Department of EEE, Arunai Engineering College, Tiruvannamalai, Tamil nadu, India. [02] S. P. Natarajan, Department of EEE & EIE, Annamalai University, Chidambaram, Tamil nadu, India. [03] R. Bensraj, Department of EEE & EIE, Annamalai University, Chidambaram, Tamil nadu, India. [04] T. S. Anandhi, Department of EEE & EIE, Annamalai University, Chidambaram, Tamil nadu, India.

This paper presents the comparison of various Unipolar Inverted Sine Carrier Pulse Width Modulation (UISCPWM) techniques for the three phase Cascaded Multi Level Inverter (CMLI). Due to switch combination redundancies, there are certain degrees of freedom to generate the multilevel AC (Alternating Current) output voltage. This paper presents the use of Control Freedom Degree (CFD) combination. The effectiveness of the pulse width modulation strategies developed using CFD are demonstrated using simulation. The results indicate that the chosen five level inverter triggered by the developed UISCPSPWM (Unipolar Inverted Sine Carrier Phase Shift Pulse Width Modulation) and UISCVFPWM (Unipolar Inverted Sine Carrier Variable Frequency Pulse Width Modulation) strategy with sine and stepped wave reference and UISCAPODPWM strategy with 60 degree reference exhibits reduced harmonics and UISCCOPWM (Unipolar Inverted Sine Carrier Carrier Overlapping Pulse Width Modulation) provides higher fundamental RMS (Root Mean Square) output voltage for all references. Simulation are performed using MATLAB-SIMULINK.

ISCPWM, CMLI, THD, 60 Degree, FF, Unipolar

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