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 implement 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.