Performance study of various discontinuous PWM strategies for multilevel inverters using generalized space vector algorithm

The space vector (SV) pulse-width modulation (PWM) approach is extensively preferred in the control of multilevel inverters (MLI). In this paper, the implementation of various advanced discontinuous pulse-width modulation (ADPWM) strategies using a generalized space vector algorithm is presented. The ADPWM MIN, ADPWM MAX, and ADPWM 0 ~ ADPWM 3, strategies are developed using a combination of advanced switching sequences 1012-2721 and 0121-7212. The output performance in terms of voltage THD, current THD, and reduction of common mode voltage (CMV) of a three-level inverter-fed induction motor for different ADPWM strategies is investigated initially through MATLAB simulation and comparison of the obtained results is presented. It can be observed that the ADPWM 1 strategy with the 0121–7212 switching sequence offered the best performance in terms of the voltage and current THD at the modulation range of 47.5 Hz to 50 Hz. In addition, it is validated experimentally. Experimental work is done on a V/f-controlled three-level inverter-fed induction motor with the help of dSPACE. To validate the study, experimental results of the line voltage, stator current, and CMV waveforms for the ADPWM 1 (optimal performance PWM strategy) are presented in comparison with the 0127 sequence at fundamental frequencies of 49 Hz and 30 Hz.