The control of arm currents and the parameters for modular multilevel converters

This paper describes the operation of modular multilevel converter (MMC). A control method of adding the feed-forward current is introduced. Another strategy of removing the second harmonic current is also described in order to improve the arm currents. Simulation results based on a detailed PSIM model prove the effectiveness of the two methods. The paper presents principle of parameters selection of MMC especially the arm inductance.