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Pulse Width Modulation (PWM) and Model Predictive Control (MPC) are two switching methods for Modular Mutlilevel Converter (MMC) presented in the literature [1], [2]. PWM switching cannot mitigate circulating currents in the converter bridges. An MPC method proposed in [2] compares all switching sequences and finds the optimal one to minimize the objective function (a weighted sum of the absolute values of the ac current deviation, capacitor voltage deviation, and the circulating current of the next time step). The computation effort is significant when the numbers of submodules increase. In this paper, a one-step model predictive control with minimum computing effort has been proposed to control the ac currents, keep the capacitor voltages nominal, and mitigate the circulating currents. The algorithm determines the ideal values of the lower-level and upper-level voltages on each phase based on the current …