This paper develops step-by-step a complete electric model of a light hybrid electric vehicle propulsion system. This model includes the vehicle mass, the radius and mass of the wheels, the aerodynamic profile of the vehicle, the electric motor and the motor drive, among other elements. Each element of the model is represented by a set of equations, which lead to getting an equivalent electric circuit. Based on this model, the outer and inner loop compensators of the motor drive control circuit are designed to provide stability and a fast dynamic response to the system. To achieve this, the steady-state equations and the small-signal model of the equivalent electric circuit are also obtained. Furthermore, as these elements are the main load of the power distribution system of the fully electric and light hybrid electric vehicle, the input impedance model of the set composed of the input filter, the motor drive, the motor, and the vehicle is presented. This input impedance is especially useful to get the system stability of the entire power distribution system.

The design of the optimal power distribution system (PDS or powertrain) for fuel cell-based vehicles is a complex task due to PDS comprising one or more power converters, several types of secondary energy sources, a fuel cell, several control loops, and protections, among others. The optimized powertrain design tries to minimize the mass, volume, and cost, and also to improve system efficiency, fuel economy (both hydrogen and electricity), and vehicle autonomy. This paper analyzes the influence of four different factors that deeply affect the optimal powertrain design, in particular: the minimum power delivered by the fuel cell, the storage of the recovered energy from the regenerative braking periods, the battery technology, and the maximum battery state-of-charge variation. The analysis of these factors is carried out over a set of 9 different fuel cell-based architectures applied to a light vehicle, and a 10th architecture corresponding to a pure electric vehicle. This analysis provides the knowledge of how these design factors affect the mass, volume, and cost of the optimal power distribution architectures, and how they can be considered in the design.

The fuel cell based vehicles powertrain is an extensive system that comprises a fuel cell (FC) as the primary energy source, a set of power converters both unidirectional and bidirectional and batteries or supercapacitors as secondary energy sources. Its design is a complex task that affects the mass, volume, cost, efficiency and fuel economy of the vehicle. This paper describes a graphic and straightforward sizing of the secondary energy sources needed to fulfil the vehicle load requirements, as well as the set of equations related to the mass, cost and volume of each one of the power distribution subsystems. Moreover, this paper analysis ten different power distribution architectures to conclude which is the most suitable secondary energy source, the minimum sizing, cost, volume and weight, depending on the amount of power delivered by the fuel cell. Also, a 1.6 kW fuel cell based architecture is implemented and testing. The experimental results confirm the proposed methodology.

Fuel cells are one of the most promising energy sources, especially for onboard applications. However, fuel cells present several drawbacks, such as slow dynamic response, load-dependent voltage, and unidirectional power flow, which cause an inappropriate vehicle operation. So, secondary energy sources and power converters must be implemented in order to satisfy fast changes in the current load and to store the energy delivered by the load if regenerative braking is intended. Taking into account the number and nature of the power converters, loads, secondary energy sources, and the possibilities for the control strategies, the design of a power distribution architecture based on fuel cells for transport applications is a complex task. In order to address these architectures, modeling and simulation design tools at system level are essential. This paper proposes a complete fuel cell black-box model which reproduces the behavior of a commercial fuel cell with overshooted transient response. The identification technique applied to parameterize the model components, based on manufacturer's datasheets and a test based on load steps, is explained thoroughly. In addition, if only the fuel cell frequency response and manufacturer's datasheet are available, an alternative parameterization methodology based on the fuel cell frequency response is presented. The fuel cell black-box model is validated experimentally using a commercial proton exchange membrane fuel cell. Two different parameterizations are carried out with the aim of verifying the robustness of both the fuel cell model and the proposed identification methodology.

The Harmonic Cancellation Technique (HCT) is a modulation technique able to reduce the output voltage THD in Auxiliary Railway Power Supplies which supply both a linear and a well-known non linear load, helping the manufacturer to achieve the output voltage THD specifications. It is based on the pre-distortion of the inverter output voltage, through the analytical determination of the IGBTs switching events. So, along this paper the limitations of the available solutions space for the HCT is presented, along with some design parameters which may help to enlarge it. Streszczenie. Technika redukcja harmonicznych (HCT) jest metodą modulacji umozliwiającą zmniejszenie wartości wspolczynnika THD w napieciu wyjściowym trakcyjnego źrodla potrzeb wlasnych, zasilającego zarowno odbiorniki liniowe jak i dobrze znane odbiorniki nieliniowe. Metoda ta, umozliwiająca producentom osiąganie wymaganego w specyfikacji wspolczynnika THD, bazuje na ocenie odksztalcenia napiecia wyjściowego falownika, poprzez analityczne wyznaczenie chwil przelączen IGBT. W artykule przedstawiono ograniczenia techniki HCT oraz kilka parametrow konstrukcyjnych, umozliwiających rozszerzenie mozliwości jej zastosowania. (Ocena mozliwych obszarow zastosowania techniki modulacji HCT).

The auxiliary railway power supply (ARPS) is needed in order to provide low and medium voltages to the onboard systems from the catenary high voltage. The outputs of the ARPS can be dc (24 V dc ÷100 V dc ) or ac (400 V ac ). In the case of ac voltage generation, the ac output voltage is under very restrictive total harmonic distortion specifications even in the presence of nonlinear loads which draw low-frequency current harmonics. Along the present paper, a new modulation technique is proposed under the name of harmonic cancellation technique. It is based on the proper pre-distortion of the inverter output voltage in order to generate a controlled fundamental harmonic as well as a set of low-frequency harmonics which cancel out the harmonic pollution due to the nonlinear load performance. The theoretical background needed to implement the modulation technique is provided as well as the experimental validation of the proposed modulation technique through a scale-down prototype.

AC voltage generation in rail applications (auxiliary services), usually employs optimized PWM feedforward schemes in order to control the inverter. In this kind of applications the THD reduction of the filtered output voltage together with the reduced weight of the static converters are the main goals to be reached. In order to achieve these objectives, the most commonly used optimized PWM techniques are going to be compared in terms of total harmonic distortion (THD), weighted total harmonic distortion (WTHD) and IGBT losses.