Level Selection Algorithm with Fixed Sampling Frequency for Modular Multilevel Converter

Abstract

This paper deals with a level selection algorithm with fixed sampling frequency for Modular Multilevel Converter(MMC) system. Theoretically, the proposed method increases the level infinitely while the sampling time remains the same. The proposed method called Cluster Stream Buffer(CSB) consists of several cluster where each cluster is composed of 32 (or 17) submodules. For an increase in the level of the MMC system, additional clusters are used and the sampling time between clusters is determined from the sampling time between levels needed for utilizing the entire level from the MMC system. This method plays a vital role in the control of MMC type HVDC system by improving its scalability and precision.