Control Strategy for a Modified Cascade Multilevel Inverter With Dual DC Source for Enhanced Drivetrain Operation.

This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase series-connected to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimize energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimize switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications. [ABSTRACT FROM AUTHOR]