Minimal Capacitor Voltage Ripple Control for the Modular Multilevel Converter Based Wind Energy Conversion System

Owing to the demand for larger wind turbine generators, the megawatt wind energy, conversion system using the modular multilevel converter (MMC) has shown great potential in this area. However, the capacitor voltage of this topology is floating, whi0ch leads to the requirement of large capacitor and the increment of project cost. This paper proposes a minimal capacitor voltage tipple (MCVR) control for the MMC-based wind energy conversion system. In the method, the second and third harmonic components of the capacitor voltage are controlled to counteract its fundamental component. With the proposed MCVR control, the capacitor voltage ripple can be reduced without influencing the maximum power point tracking of the wind energy conversion system. Finally, the effectiveness of the proposed method is validated in MATLAB/Simulink.