VOLTAGE BALANCE BASED ON CAPACITOR VOLTAGE VALUE SORTING ALGORITHM IN THE MMC CONVERTER

Abstract

The application of MMC converters to power systems has many advantages such as: operation at high voltage, large capacity. The problem of MMC when applying NLM modulation is to balance the voltage on the capacitors to ensure stable operation of the MMC. This paper proposes a voltage balance algorithm on the capacitor by arranging the capacitor voltage value to select the ON and OFF of the SMs. The algorithm is implemented by program the arrangement of the capacitor voltage value measure from the sensors to select the appropriate SMs to be turned on in a modulation cycle in order to ensure the capacitor voltage balance between the SMs. The algorithm is applied to the MMC model with 13 AC voltage levels and is verified by simulation on Simulink software and system experiments to prove that the algorithm implementation is feasible.