IEEE Vehicle Power and Propulsion Conference (VPPC), September 3-5, 2008, Harbin, China

Modeling and Simulation of Hybrid Electric Vehicles Using HEVSIM and ADVISOR

Jun HOU* and Xuexun GUO**

* Wuhan University of Technology/ School of Automobile Engineering, Wuhan, China. Email: ** Wuhan University of Technology/ School of Automobile Engineering, Wuhan, China. Email:

Abstract—This paper discusses a simulation and modeling package developed at Wuhan University of Technology, HEV Simulator (HEVSIM). HEVSIM was written in the Matlab/Simulink graphical simulation language and is portable to most computer platforms. First, comparisons are made for three different hybrid electric topologies according to their power assembly, power-train, control strategies and drive cycles. Then it has been reviewed that two different modeling and simulation methods, the forward- and backward- facing simulation approaches. The modeling and simulation capabilities of existing tools such as ADvanced VehIcle SimulatOR (ADVISOR), HEVSIM are demonstrated through application examples. Differences are given between HEVSIM and ADVISOR2002 based on the two simulation methods. A series HEV and a parallel HEV drive train have been designed using the ADVISOR and HEVSIM respectively. Simulation results such as fuel consumption, vehicle emissions, and complexity are illustrated and discussed for each vehicle.

Keywords—Electric Vehicle; Hybrid Electric Vehicle; HEVSIM ; ADVISOR; Simulation

I. INTRODUCTION

vehicles can meet the criteria outlined in the national Presently, only electric and low-emissions hybrid regulations which require a progressively increasing percentage of automobiles to be ultralow or zero emissions. Pure electric vehicles are propelled only by an electric motor, and a battery pack provides it with electricity. Existing hybrid electric designs can be broken into three basic categories, series, parallel, and combined series/parallel. The vehicle is characterized by the connection of the various components within the vehicle and the energy flow pathway. A series hybrid consists of a power plant providing electricity (i.e. internal combustion engine (ICE)/generator combination, or fuel cell system) to a battery pack. The vehicle is then propelled by an electric drive motor. The power plant is not coupled directly to the wheels and can run in its most efficient operating region. In a parallel hybrid, the power plant (ICE) and the electric motor can both provide power to the driveline in parallel. This design provides a direct mechanical path for power delivery between the engine and the wheels. A combined series/parallel hybrid, like the Toyota Prius, exhibits some of the characteristics of both parallel and series hybrids.

Though purely electric vehicles (EVs) are a promising technology for the long-range goal of energy efficiency and reduced atmospheric pollution, their limited range and lack of supporting infrastructure may hinder their public

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C2008 IEEE. acceptance. Hybrid vehicles offer the promise of higher energy efficiency and reduced emissions when compared with conventional automobiles, but they can also be designed to overcome the range limitations inherent in a purely electric automobile by utilizing two distinct energy sources for propulsion.

Computer modeling and simulation can be used to reduce the expense and length of the design cycle of hybrid vehicles by testing configurations and energy management strategies before prototype construction begins. Interest in hybrid vehicle simulation grew in the 1970’s with the development of several prototypes that were used to collect a considerable amount of test data on the performance of hybrid drive trains. Studies were also conducted to analyze hybrid electric vehicle (HEV) concepts. Several computer programs have since been developed to describe the operation of hybrid electric powertrains, including: simple EV simulation (SIMPLEV) from the DOE’s Idaho National Laboratory [1], MARVEL from Argonne National Laboratory [2], CarSim from AeroVironment Inc., JANUS from Durham University [3], ADVISOR from the DOE’s National Renewable Energy Laboratory [4], Vehicle Mission Simulator [5], and others [6], [7]. ADVISOR is more popular than other computer programs because it is freely available via Internet. The program evaluates the performance of a vehicle in a combined backward-forward facing approach. On a time basis, the program calculates what is required from each component, working backwards through the vehicle from the wheels to the powerplant, in order for the vehicle to follow the desired speed trace. As the requirements are passed from one component to the next, performance limits are enforced. On the forward path, the performance of the downstream components is updated based on limits enforced in upstream components. This approach simplifies the calculation process and eliminates the need to iteratively solve at each time step. The disadvantage in this approach is that it is difficult to generate true control algorithms that can be carried directly to a finished product.

HEVSIM is a system-level modeling, simulation, and analysis package developed at Wuhan University of Technology using Matlab/Simulink to study issues related to EV and HEV design such as energy efficiency, fuel economy, and vehicle emissions. HEVSIM facilitates in-depth studies of power plant configurations, component sizing, energy management strategies, and the optimization of important component parameters for several types of hybrid or electric configuration or energy management strategy. It uses visual programming techniques, allowing the user to quickly change