Fault Ride-Through Scheme and Control Strategy of Multilevel Voltage-Balancing DC-DC Converter

Multilevel voltage-balancing DC-DC converter (MVBDC) generally shows the advantages of simple structure and control, modularization, low electrical stress of switches, bidirectional energy flow, high power density and efficiency, which has good prospect in high-power and high-voltage DC-DC application. However, with increasing voltage level of MVBDC, both the number of modules and the potential risk of fault increases. Therefore, the fault ride-through scheme and control strategy of MVBDC are proposed in this paper. By introducing the improved modules and redundant modules, the fault ride-through MVBDC (FRT-MVBDC) may achieve fault protection. Based on the analysis of topology and principle of FRT-MVBDC, the fault characteristics and fault ride-through strategy are discussed in detail. Finally, the simulation model of FRT-MVBDC is built to verify the fault ride-through performances with proposed control strategy.