Inner current control method for modular multilevel converter applied in motor drive

This paper presents the modular multilevel converter as medium voltage motor driver. An investigation of the capacitor requirements is performed and a novel control method, based in the inner current control, is proposed. This method can ensure the capacitor balancing as well minimizes the harmonic current in the converter phases. The control method is evaluated by computational simulations of a three-phase driver of a 350 kW, 2.3 kV induction motor. The simulated results have proven the effectiveness of the control structure in the startup procedure and steady state operation.