Electric and Hybrid Vehicles: Technologies, Modeling and Control - A Mechatronic Approach

5Modelling and Characteristics of EV/HEV Powertrains Components

5.1 Introduction

Generally, an EV/HEV powertrain includes distinct components such as power unit(s), an internal combustion engine and/or electric motor(s), a transmission system, and batteries. Performance analysis of an EV/HEV powertrain system requires the modeling of each integrated component. Depending on the powertrain topology, component models should be combined to form the overall powertrain model. Components of a powertrain system can be mathematically modeled by using the laws of physics to arrive at a set of differential equations representing powertrain dynamics. Physics-based models are very powerful tools for the design and optimization of powertrain systems. However, they are complicated and sometimes do not match the experimental results exactly.

Alternatively, output power and torque, as well as the energy consumption and efficiency of a powertrain system can be calculated through characteristic curves instead of complicated physics-based models. Characteristic curves illustrate the results of standard experiments with sufficient accuracy.

Driving cycles also are an important tool in the design and offline evaluation of powertrain systems. There are different driving cycles representing urban and highway driving conditions for different geographical regions.

This chapter discusses the performance characteristics, mathematical models, and efficiencies of EV and HEV powertrain components, as well ...