The paper suggests a power traction converter for battery electrical vehicles (BEV) based on a modular multilevel topology integrated with supercapacitor energy storage system (ESS). The relevant contribution is given by the integration of a control method for mitigating the ac voltage fluctuation at low speed operation, with an energy management control strategy. Some numerical simulations referring to a 400 V, 37 kW traction drive is presented in order to verify the effectiveness of the proposed controls.