A new multi carrier based PWM for multilevel converter

Abstract

This paper addresses a new multi-carrier modulation technique called wave shift multi-carrier modulation (WSHM), which used to control the cascade multilevel converter (CMC). The proposed switching technique generates lower voltage total harmonic distortion (THD) in comparison with conventional multi-carrier based pulse width modulation (PWM) schemes, phase-shift (PSHM) and level-shift (LSHM) modulations. To compare the performance of proposed method with PSHM and LSHM techniques, a simulation circuit of seven and nine levels for CMC is designed and simulated. To complete the comparison between the proposed method and PSHM, LSHM the dynamic behavior of dynamic voltage restorer (DVR) based seven-level CMC for power quality improvement is investigated. Digital simulations are carried out using PSCAD/ EMTDC to validate the performance of CMC.