Calculation of the number of modules and the switching frequency of a modular multilevel converter using near level control

This paper is focused on the modular multilevel converter (MMC) topology that uses the near level control (NLC) method. Specifically, it addresses the relationship between the number of levels or switching modules, the switching frequency and the harmonics superimposed on the generated voltages and currents, making a comparison with the high and medium voltage AC codes. Furthermore, it also assesses the possibility of connecting the MMC to the electrical grid without using any coupling inductor, either using a transformer or simply directly. Finally, it shows how to automate the simulations necessary to select the number of levels and the switching frequency.