A voltage-balanced hybrid MMC topology for DC fault ride-through

This paper proposes a voltage-balanced HBSMCDSM hybrid MMC topology. This topology adds diodes between sub-modules based on the traditional HBSM-CDSM hybrid topology. The diode's single-conductivity provides a new loop for fault current removal and changes the characteristics of bypassing HBSM during faults. The new topology can quickly clear the fault current during the fault, and evenly distribute the energy on the capacitance of each sub-module, so that the voltage of each capacitor is balanced, which is beneficial to the quick start of the system after the fault ends. On this basis, this paper also proposes a fault ride-through control strategy in which the DC switch is matched with the voltage-balanced hybrid MMC topology. This strategy can achieve fast isolation of DC faults and system recovery without controlling the AC circuit breaker. Finally, the effectiveness of the above method is verified in MATLAB/Simulink.