Cell Capacitor Voltage Switching-Cycle Balancing Control for Modular Multilevel Converters

Modular multilevel converters (MMC) with the conventional control are subjected to large capacitor voltage ripples, especially at low-line frequencies. The existing attenuation approaches, such as the second-order or high-frequency harmonic injections, are designed based on average models limiting the achievable performance. This letter aims to greatly increase the control time resolution, investi...