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

Abstract

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 seriesconnected respectively 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 optimise energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimise switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications.

Mathematical Modeling and Analysis of Capacitor Voltage Balancing for Power Converters with Fewer Switches

“…Several issues exist with the three-phase alternating machine and system supply PWM signaling approaches [9]. Since low-level inverters contain nonlinear elements such as MOSFET and IGBT, they may also produce waveforms with harmonics using pulse-width modulation (PWM) [10]. Nonlinear impacts such as distortion caused by harmonics develop on the outputs of load when the amount of the element has risen on the inverter.…”