Study On Normal Modular Multilevel Converter And Its Control Strategy

With the rapid development in the past half a century, power elevtronics has been widely used in various fields. In the field of low-voltage and small-power, power electronics has become increasingly mature; Whereas in the field of high-voltage and high-power, all aspects such as HVDC, FACTS, large motor drive and power supply devices are becoming a hot research. There are so many solutions for power electronics to achieve high-voltage and high-power conversion. But attention has been paid to multi-level converter for it’s lower stress of switching devices, lower electromagnetic interference and smaller output waveform THD content, etc., and began to be widely studied and used.Modular multi-level converter is a new topology in voltage source converter based on HVDC field. Due to its characteristics of good scalability, modularity and low harmonic content of the output waveform, modular multi-level conterver can satisfy the requirements of future power conversions in high or medium voltage. Based on the analysis of traditional modular multi-level converter, this paper mainly focused on the analysis and descirption of the novel modular multi-level converter’s topology and control strategy, then build the simulation platform based on MATLAB/SIMULINK and experiment platform to verify the correctness of the modulation technique, at lastThe main research contents of the paper are as follows:1. Summary of the background, status and topology about multi-level converter, and then take a brief introduction to the various control strategies.2. Introduce the topological structure, working principle and PWM modulation strategy for the modular multi-level converter, and then build the simulation platform based on MATLAB/SIMULINK to verify the correctness of the carrier phase shifted PWM modulation technique.3. Introduce a novel modular multi-level converter: a single phase bridge-module unit seried multi-level converter, and then propose two kinds of modulation strategies, build the corresponding simulation platform, at last the proposed modulation strategy was analyzed and validated.4. Introduce a novel modular multi-level converter: a three phase bridge-module unit seried multi-level converter, and then propose two kinds of modulation strategies, build the corresponding simulation platform to verify the validity of the proposed modulation strategy.5. Establishe experimental platform for a single phase multi-level converter, and take a brief introduction of its hardware component and control system, further verify the validity of the proposed modulation strategy according to the experimental platform.