Analytical approach to obtain the harmonics spectra on a five level cascaded inverter with subjected to a new modulation scheme

Abstract

This paper is intended to outline the analytical method to obtain the harmonics spectra of a five level cascaded inverter which is subjected to a new modulation scheme. The motivation of such exercise is to avoid the problem of spectra calculation inaccuracies when using the MATLAB-Simulink time-based block simulation approach. The inaccuracy is known to be severe at higher modulation ratio, i.e. for small PWM pulses [McGrath, B.P. and Holmes, D.G., 2000]. An experimental five-level cascaded inverter is build and the proposed modulation scheme is implemented. The calculated and measured spectra are compared and discussed.