Special Section on Vehicular Energy-Storage Systems

The ten papers in this special section focus on state-of-the-art research and development and future trends in the modeling, design, control, and optimization of energy-storage systems for electric vehicles (EVs), hybrid electric vehicles (HEVs), fuel cell vehicles, and plug-in HEVs.     

The State of the Art of Electric, Hybrid, and Fuel Cell Vehicles

With the more stringent regulations on emissions and fuel economy, global warming, and constraints on energy resources, the electric, hybrid, and fuel cell vehicles have attracted more and more attention by automakers, governments, and customers. Research and development efforts have been focused on developing novel concepts, low-cost systems, and reliable hybrid electric powertrain. This paper reviews the state of the art of electric, hybrid, and fuel cell vehicles. The topologies for each category and the enabling technologies are discussed     

Power Semiconductor Devices for Hybrid, Electric, and Fuel Cell Vehicles

Power semiconductor devices are key components in all power electronic systems, particularly in hybrid, electric, and fuel cell vehicles. This paper reviews the system requirement and latest development of power semiconductor devices including IGBTs, freewheeling diodes, and advanced power module technology in relating to electric vehicle applications. State-of-the-art silicon device technologies, their future trends, and theoretical limits are discussed. Emerging wide bandgap semiconductor devices such as SiC devices and their potential applications in electric vehicles are also reviewed     

一种基于Z源逆变器的燃料电池汽车变换器

在燃料电池汽车中,电能转换是一个核心问题。结合燃料电池的特性,简要说明了燃料电池汽车中现有变换器的不足。同时,为了克服传统燃料电池汽车电能变换器两级结构固有的不足,进一步提高其稳定性,提出了一种性能较高的Z源逆变器,分析了该结构的工作原理,采用了一种新型的具有直通零矢量的三相电压空间矢量调制方法,介绍了其工作特点以及直通零矢量的产生方法,进行了相关的仿真实验。仿真结果表明,该电路结构能够达到较高的性能要求,适合在燃料电池汽车上应用。     

An impedance-based approach to predict the state-of-charge for carbon-based supercapacitors

The impedance behavior of supercapacitors is not only a key issue for the parameterize modeling of the supercapacitor, but also an important factor for the design processes of an intelligent energy-management system which monitors the state of the supercapacitor and predicts its performance. In this paper, a simple equivalent circuit model and convolution algorithm based on impedance analysis were presented to assess state-of-charge, terminal voltage and charge/discharge capability of supercapacitors. Furthermore, an impedance function based on the equivalent impedance model was established to simulate the dynamic performance of a supercapacitor. The results can be used to control the reliable prediction of supercapacitors performance in electric vehicles, hybrid electric vehicles, fuel cell vehicles and classical automotive applications.     

Engineering the EV future

Continuing environmental concerns are moving electric vehicles (EV) into high gear at development facilities everywhere. The General Motors EV1 and the Ford Ranger EV are old news, the 106 Electric from PSA Peugeot-Citroen is established in France, where more than 1500 have been sold, and Toyota's Prius hybrid electric vehicle has exceeded all expectations in Japan, with plans afoot for an early introduction in the United States. In share-of-market terms, electric vehicles (EVs) are just beginning their infancy, total worldwide sales will be measured in the thousands of cars in 1998, compared with perhaps 20 million vehicles sold in all. But the big companies at long last are taking EVs seriously. The question now seems to be not whether automobiles will go electric but when. Battery, fuel cell and hybrid vehicles are briefly reviewed in this article     

Fuel cells for the long haul, batteries for the spurts [electricvehicles]

Until only a few years ago, when environmentalists, automakers, and other concerned parties spoke about low-emissions vehicles, they were almost always referring to electric vehicles (EVs)-cars, trucks, and buses powered by batteries of one kind or another. Today, having so far failed in their quest for a battery that could make EVs practical, they are looking more and more to hybrid electric vehicles (HEVs), which automakers had hitherto rejected as merely an interim solution. But hybrids based on a combination of electric motors and internal combustion engines are attractive for two main reasons: they require no technology breakthroughs and no new infrastructure. They work with existing batteries since they do not rely on them for primary energy storage; rather, they can obtain fuel at any service station. An alternative to HEVs is fuel cell powered vehicles. The principles of this technology and the associated hydrogen storage issues are discussed. Other alternative fuels are briefly outlined     

Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug-In Hybrid Electric Vehicles

With the requirements for reducing emissions and improving fuel economy, automotive companies are developing electric, hybrid electric, and plug-in hybrid electric vehicles. Power electronics is an enabling technology for the development of these environmentally friendlier vehicles and implementing the advanced electrical architectures to meet the demands for increased electric loads. In this paper, a brief review of the current trends and future vehicle strategies and the function of power electronic subsystems are described. The requirements of power electronic components and electric motor drives for the successful development of these vehicles are also presented.     

Transportation [Technology 1998 analysis and forecast]

The safety debate has taken a new twist in both the aviation and the rail industries. High-profile aviation disasters and freight train wrecks have prompted demands for another great leap forward in safety. In both industries, new technology is playing a key role. And in the automotive field, public health will be the ultimate beneficiary if electric or hybrid electric vehicles start coming into wider use now that manufacturers have announced significant improvements in range. An enhanced ground proximity warning system for aviation, automatic train control, development of high speed trains, and electric vehicles powered by batteries and fuel cells, are discussed     

Powering Sustainable Mobility: Roadmaps of Electric, Hybrid, and Fuel Cell Vehicles

In a world where environmental protection and energy conservation are growing concerns, the development of electric, hybrid, and fuel cell vehicles has taken on an accelerated pace. The dream of having commercially viable electric and hybrid vehicles is becoming a reality. It is important that the automobile companies have both proper technical and commercialization roadmaps hand-in-hand. The company CEOs should take the lead in drawing the technical and commercialization roadmaps. This task should not just be dedicated to the R&D departments or sales departments, since this is a major project that will have major effects on the company and society. In addition to having clear objectives, the senior management should also have holistic and creative thinking to oversee the progress of the project.     

Effects of drivetrain hybridization on fuel economy and dynamic performance of parallel hybrid electric vehicles

Hybrid electric vehicles have proved to be the most practical solution in reaching very high fuel economy as well as very low emissions. However, there is no standard solution for the optimal size or ratio of the internal combustion engine and the electric system. The optimum choice includes complex tradeoffs between the heat engine and electric propulsion system on one hand and cost, fuel economy, and performance on the other. Each component, as well as the overall system, have to be optimized to give optimal performance and durability at a low price. In this paper, we look at the effects of hybridization on fuel economy and dynamic performances of vehicles. Different hybridization levels from mild to full hybrid electric traction systems are examined. We also present the optimum level of hybridization for typical passenger cars. This study shows that low hybridization levels provide an acceptable fuel economy benefit at a low price, while the optimal level of hybridization ranges between 0.3 and 0.5, depending on the total vehicle power.     

Are hybrid vehicles worth it?

In this paper, the author describes how, despite superior fuel economy and low emissions, hybrid electric vehicles (HEVs) cost too much at present to make economic sense     

Top 10 tech cars

This article gives an overview of technical advances in automobiles. It covers such diverse areas as: hybrid vehicle drive trains; white LED lighting; roll stability control; active steering control; electric vehicles; hydrogen powered vehicles; 42 V automotive electrical systems; and fuel cells.     

Unified modeling of hybrid electric vehicle drivetrains

Hybridizing automotive drivetrains, or using more than one type of energy converter, is considered an important step toward very low pollutant emission and high fuel economy. The automotive industry and governments in the United States, Europe, and Japan have formed strategic initiatives with the aim of cooperating in the development of new vehicle technologies. Efforts to meet fuel economy and exhaust emission targets have initiated major advances in hybrid drivetrain system components, including: high-efficiency high-specific power electric motors and controllers; load-leveling devices such as ultracapacitors and fly-wheels; hydrogen and direct-methanol fuel cells; direct injection diesel and Otto cycle engines; and advanced batteries. The design of hybrid electric vehicles is an excellent example of the need for mechatronic system analysis and design methods. If one is to fully realize the potential of using these technologies, a complete vehicle system approach for component selection and optimization over typical driving situations is required. The control problems that arise in connection with hybrid power trains are significant and pose additional challenges to power-train control engineers. The principal aim of the paper is to propose a framework for the analysis, design, and control of optimum hybrid vehicles within the context of energy and power flow analysis. The approaches and results presented in the paper are one step toward the development of a complete toolbox for the analysis and design of hybrid vehicles     

Energy management strategies for vehicular electric power systems

In the near future, a significant increase in electric power consumption in vehicles is expected. To limit the associated increase in fuel consumption and exhaust emissions, smart strategies for the generation, storage/retrieval, distribution, and consumption of electric power will be used. Inspired by the research on energy management for hybrid electric vehicles (HEVs), this paper presents an extensive study on controlling the vehicular electric power system to reduce the fuel use and emissions, by generating and storing electrical energy only at the most suitable moments. For this purpose, both off-line optimization methods using knowledge of the driving pattern and on-line implementable ones are developed and tested in a simulation environment. Results show a reduction in fuel use of 2%, even without a prediction of the driving cycle being used. Simultaneously, even larger reductions of the emissions are obtained. The strategies can also be applied to a mild HEV with an integrated starter alternator (ISA), without modifications, or to other types of HEVs with slight changes in the formulation.     

Dynamic simulation for analysis of hybrid electric vehicle system and subsystem interactions, including power electronics

Simulation tools for hybrid electric vehicles (HEVs) can be classified into steady-state and dynamic models, according to their purpose. Tools with steady-state models are useful for system-level analysis. The information gained is helpful for assessing long-term behavior of the vehicle. Tools that utilize dynamic models give in-depth information about the short-term behavior of sublevel components. In this paper, a dynamic model of a hybrid electric vehicle that includes fuel cells, batteries, ultracapacitors, and induction machine drives is presented. Simulation results of vehicle configurations with a battery, a fuel cell-battery combination and a fuel cell-ultracapacitor combination are discussed. The focus of the model is a detailed assessment of different subsystem components, particularly component losses.     

The state of the art of electric and hybrid vehicles

In a world where environment protection and energy conservation are growing concerns, the development of electric vehicles (EV) and hybrid electric vehicles (HEV) has taken on an accelerated pace. The dream of having commercially viable EVs and HEVs is becoming a reality. EVs and HEVs are gradually available in the market. This paper will provide an overview of the present status of electric and hybrid vehicles worldwide and their state of the art, with emphasis on the engineering philosophy and key technologies. The importance of the integration of technologies of automobile, electric motor drive, electronics, energy storage, and controls and also the importance of the integration of society strength from government, industry, research institutions, electric power utilities, and transportation authorities are addressed. The challenge of EV commercialization is discussed     

Innovative iteration algorithm for a vehicle simulation program

Resulting from Ph.D. research, a vehicle simulation program is proposed and continuously developed, which allows simulation of the behavior of electric, hybrid, fuel cell, and internal combustion vehicles while driving any reference cycle. The goal of the simulation program is to study power flows in the drivetrains of vehicles and the corresponding component losses, as well as to compare different drivetrain topologies. This comparison can be realized for energy consumption and emissions, as well as for performance (acceleration, range, maximum slope, etc.). The core of this program, consisting of a unique iteration algorithm, will be highlighted in this paper. This algorithm not only allows the calculation of the limits of vehicle acceleration in the function of drivetrain component characteristics, but at the same time is able to develop and evaluate the different power-management strategies of hybrid vehicles, combining combustion engines and electric motors. Furthermore, the comprehensive iteration algorithm is demonstrated to be very efficient in handling any type of working limit for all components in different types of drivetrains, which results in an accurate and modular vehicle simulation program with high data flexibility.     

Modeling of a Series Hybrid Electric High-Mobility Multipurpose Wheeled Vehicle

In an effort to reduce fuel costs and gas emissions, the U.S. Army is looking into replacing their diesel high-mobility multipurpose wheeled vehicle (HMMWV) with hybrid electric vehicles. The aim of this paper is to present the simulation of the series hybrid electric HMMWV based on a multidomain model using Ansoft Simplorer. Emphasis is placed on the vehicle's transient response to desired speeds dictated by drive cycles based on an urban dynamometer driving schedule and SAE J227a Schedule D. Also included in this paper were the vehicle's responses to hill climbing up to 60% grade