Propulsion system design of electric and hybrid vehicles

TLDR

Growing environmental concerns have spurred interest in electric and hybrid‑electric vehicles, prompting efforts to develop improved propulsion systems. The paper aims to develop system‑design philosophies for electric and hybrid vehicle propulsion systems. The authors analyze vehicle dynamics to determine an optimal torque‑speed profile and evaluate candidate motors operating in the constant‑power region. The study shows that meeting operational constraints such as acceleration and grade can be achieved with minimal power rating when the powertrain operates mainly in the constant‑power region, and motor comparisons confirm this advantage.

Abstract

There is a growing interest in electric and hybrid-electric vehicles due to environmental concerns. Efforts are directed toward developing an improved propulsion system for electric and hybrid-electric vehicles applications. This paper is aimed at developing the system design philosophies of electric and hybrid vehicle propulsion systems. The vehicles' dynamics are studied in an attempt to find an optimal torque-speed profile for the electric propulsion system. This study reveals that the vehicles' operational constraints, such as initial acceleration and grade, can be met with minimum power rating if the power train can be operated mostly in the constant power region. Several examples are presented to demonstrate the importance of the constant power operation. Operation of several candidate motors in the constant power region are also examined. Their behaviors are compared and conclusions are made.