Description  Claims  Drawing  Cited references 

Single-to-three-phase direct AC/AC modular multilevel converters with integrated split battery energy storage for railway interties   [0003] 
Accurate Capacitor Voltage Ripple Estimation and Current Control Considerations for Grid-Connected Modular Multilevel Converters   [0003] 
Simplified model and submodule capacitor voltage balancing of single-phase AC/ AC modular multilevel converter for railway traction purpose   [0003] 
A Medium-Voltage Large Wind Turbine Generation System Using an AC/ AC Modular Multilevel Cascade Converter   [0003]