Effect of Modulation Techniques on Capacitor Voltage of Modular Multilevel Converter

The capacitor voltage regulation is an important parameter in the stable and effective operation of Modular Multilevel Converter (MMC). This paper presents the different modulation techniques used in MMC. Phase Shift (PS) Pulse Width Modulation (PWM) have a natural capability of balancing submodule (SM) capacitor voltage. However, in Level Shifted (LS) modulation techniques lag due to this issue. Similarly, Nearest Level Control (NLC) technique have also the same issue of capacitor voltage imbalances. The possible remedies for each modulation technique to regulated capacitor voltage are implemented for synthesizing a well-shaped and less distorted output voltage waveform. The simulation is carried out in MATLAB/Simulink for five-level MMC.