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In this paper, the configuration of a parallel hybrid vehicle, called electrically peaking hybrid (ELPH) vehicle is introduced. Several operation modes of the engine and electric motor and different control strategies are analyzed. The results show that, with proper selection of the drivetrain parameters, the vehicle can satisfy the urban and highway driving with a small internal combustion engine, a small battery pack and a single gear transmission. Moreover, the vehicle does not need to charge the battery pack from the electricity network for keeping its battery SOC at a reasonable level.

Due to their harsh operating environments, military vehicle drive trains have special requirements. These special requirements are usually represented by hill climbing ability, obstacle negotiation, battlefield cross country travel, hard acceleration, high speed, etc. These special requirements need the vehicle drive train to have a wider torque and speed range characteristics than commercial vehicles. We have proved that larger constant power ratio in electric motor can significantly enhance the vehicle acceleration performance. In other words, for the same acceleration performance, large constant power ratio can minimize the power rating of the traction motor drive, thus minimizing the power rating of the power source (batteries for instance). Actually, extension of the constant power range can also significantly enhance the gradeability, which is crucial for military vehicles.

A general design methodology of the fuel cell powered hybrid vehicle drive train has been developed. With the methodology and a computer simulation program, all of the systematic parameters can be designed, such as, the rated power of the electric motor drive, fuel cell system, peaking power source as well as the energy capacity. An overall control strategy has also been developed. The main function of the control strategy is to properly control the power produced by the fuel cell system and the peaking power source, so as to meet the power demand, maintain the energy level of the peaking power source in its optimal region and operate the fuel cell system within its high efficiency region. In this paper, a design example has also been introduced in each section.

The concept of hybrid drive trains was first developed for automobiles. These drive trains allow achieving a minimum fuel consumption by properly matching the driving requirements and the engine characteristics. In this paper the authors analyze the possibility of extending this concept to railway vehicles. Basic hybrid railway vehicles are designed and discussed.

In this paper, a mild hybrid drive train has been proposed. A small electric motor with low rated voltage (42 V) is used to (1) propel the vehicle at low speed, (2) replace the fluid-coupled torque converter and (3) realize regenerative braking. With proper design and control, the fuel economy in urban driving can be significantly improved without much change from conventional drive train to the mild hybrid drive train.

Studying the dynamics of electric motor drives is not easy. Indeed, there is no unified approach to model both the mechanical and the electrical elements of the motor drive in order to bring an intuitive understanding of the dynamic behavior. Moreover, for traction purposes, the machines are often used at field-weakening operation, which can be a source of unwanted oscillations. In this paper, the gyrator-based equivalent circuit modeling is presented. The method allows the understanding of some aspects of the dynamic behavior of DC motor drives such as the interaction between electric inductances and the rotor inertia and their oscillating behavior.

The operation of an electrically peaking hybrid vehicle (ELPH) can be divided into two basic modes. • Constant or cruising speed mode in which a small internal combustion engine (ICE) is used to power the vehicle. • Peak power mode in which the combination of an electric motor and ICE is used to supply peak power for acceleration and limited-duration steep hill climbing of the vehicle. A method, by which the engine size and the speed reduction ratio from the engine to drivewheels can be developed based on the cruising mode, is presented in this paper. The electric motor power rating and the motor gear ratio to the drive wheels can then be determined, based on the acceleration and gradeability. The results show that a simple single-gear transmission would be a good selection for overall performance.