Thermal Analysis of A Novel Hybrid Multilevel Megawatt AC Drive with ETO Devices

Abstract

The hybrid multilevel converter topology was proposed recently to reduce the number of DC sources needed in a cascaded multilevel converter. This paper proposes to use the hybrid multilevel converter topology and the emerging medium voltage ETO (Emitter Turn-Off Thyristor) devices for megawatt AC drives. A case study and thermal analysis show that the proposed AC drive can have higher output power capability, higher output power quality with low device switching frequency when compared to the traditional megawatt AC drives with SPWM method under the same thermal conditions. Therefore, the proposed hybrid megawatt AC drive is an attractive low cost solution to future medium voltage drive applications with output voltage higher than 3300 V.