Simplified direct modulation prediction approach for modular multilevel converter

This paper presents a simplified direct modulation prediction approach for modular multilevel converters (MMC). By using the Euler approximation, the grid-side and circulating currents are firstly predicted to obtain the values in the next switching cycle. Then the modulations are directly calculated based on the established mathematical models for the six-arms of MMC. Subsequently, the capacitor voltage balancing control is designed according to the total on-state submodules (SMs) of each arm, aiming at reducing the computational burden. Finally, proper pulse width modulation (PWM) can be obtained based on proposed control strategy. The effectiveness of the proposed method is verified by both the simulation and experimental results. Besides, compared with the conventional method, the superiority of the proposed approach is increasing with the voltage levels to lessen the computational burden.