Efficiency Improvment of Toyota Prius Power Train Using a 3Level NPC and Selected Harmonic Elimination Technique

Abstract

Although many converters are proposed for using in electric vehicles (EVs) application, due to the increasing growth of EVs, the choice of a suitable and efficient converter, both technically and efficiency, is worthwhile and difficult. In conventional architecture, a 2-level inverter as well as boost converter are used to control the motor speed. However, efficiency of the boost converter drop at light load condition. Therefore, in this paper, application of a 3-level neutral point clamp converter (3L-NPC), using 600V MOSFET switch instead of 1.2 kV switching devices which leads to significant cost reduction, is considered for EVs. In addition, a selective harmonic elimination (SHE) modulation technique is designed to improve efficiency of the EV power train inverter for every operating point. Moreover, using SHE modulation, there is no need for a variable gain boost converter. Finally, a 3L-NPC and conventional 2-level inverter architecture is chosen for Toyota Prius power train to simulate in MATLAB/Simulink environment using Sim-Power-System and PLECS Blocksets for a driving cycle.