Mohammad Sotoodehkia - Department of Electrical Engineering, Kish International Branch, Islamic Azad University, Kish Island, Iran
Mohammad Arasteh - Department of Electrical Engineering, University of Science and Culture, Tehran, Iran
Soodabeh Soleymani Mucheh Khorti - Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Majid Hoseinpour - Department of Electrical and Computer Engineering, University of Mohaghegh Ardabili, Ardabil, Iran

In this paper, the process of designing and comparing cascaded H-bridge (CHB) converter, modular multilevel converter (MMC), and five-level active neutral-point clamped (۵L-ANPC) converter as a solid-state transformer (SST) utilized in the distribution network was investigated. The design was based on ۱.۷ kV IGBT modules (for CHB and MMC converters) and ۳.۳ and ۴.۵ kV IGBT modules (for ۵L-ANPC converter). The converters were compared at voltage levels of ۶.۹, ۱۱, and ۲۰ kV and power levels of ۰.۵ and ۲ MW. As well, when the number of MC voltage levels increases, the complexity of the control system, as well as the control algorithm, increases largely. In order to simplify the control system, a hierarchical control system is designed for these MCs. In the process of designing converters, thermal analysis and selecting smaller parts with lower losses due to enhanced efficiency were considered.

Active NPC (ANPC), Cascaded H-bridge (CHB), Modular multilevel converter (MMC) efficiency, Modular multilevel converter (MMC), Solid state transformers (SST), Control systems