C. Raga

Behavioural Modeling of Solid State Power Controllers (SSPC) for Distributed Power Systems

The development of new aircrafts, such as A380 and B787, has provided new opportunities in the field of electronic devices and power electronics. One of the most interesting areas is focused on the protection devices field and the management of the loads by means of the Solid State Power Controllers (SSPC). This fact is mainly due to the great increase of these devices in the architectures of the electrical power distribution systems used in the new airplanes. In this paper, the areas of interest for research groups regarding SSPC in onboard platforms are presented. Also, behavioural SSPC model has been developed according with different manufacturers datasheets. Moreover, experimental validation with commercial SSPC are presented.

Black-Box Model, Identification Technique and Frequency Analysis for PEM Fuel Cell With Overshooted Transient Response

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 manufacturers datasheets and a test based on load steps, is explained thoroughly. In addition, if only the fuel cell frequency response and manufacturers 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.

Black-Box Behavioral Modeling and Identification of DC–DC Converters With Input Current Control for Fuel Cell Power Conditioning

Fuel cells are a prime candidate for alternative power source of future on-board power distribution systems such as those for the more-electric-aircraft and electric vehicles. These systems are comprised of a large number of power converters, often provided by a variety of manufacturers. Modeling and simulation are powerful tools to evaluate the system-level behavior but, due to confidentiality of manufacturers, black-box behavioral models of the converters are required instead of the conventional ones. This paper proposes a black-box modeling and identification method of dc-dc converters with input current control for fuel-cell power conditioning. The model is simple, requires low computational cost for simulation, and the identification procedure is based on simple experiments. Moreover, the model does not represent the internal structure of the converter, so it can be provided by the manufacturer while protecting confidential data. The method is illustrated in detail and validated by making use of a commercial dc-dc converter specifically designed for fuel-cell power conditioning.

SSPC model with variable reset time, environmental temperature compensation and thermal memory effect

Solid state power controller (SSPC) is being utilized in spacecraft and aircraft power distribution system in order to replace conventional electro-mechanical circuit like breakers, contactors and relays. Since power distribution on-board systems are very complex, SSPC models play an important role in order to predict the real behaviour and to avoid design fails in future applications. The main aim of this paper is to obtain a generic SSPC model based on datasheets provided by manufacturers. This model has to take into account the current-squared-time curve (I t), the environmental temperature, the thermal memory effect and the reset time. With this model it is possible to simulate and to analyze the influence of the switching of different types of loads in a power distribution system, in order to predict future problems. In addition, the model can guide SSPC designer to optimize better component performance. The SSPC model has been validated by means of simulation and experimental measurement.

High level decision methodology for the selection of a fuel cell based power distribution architecture for an aircraft application

The selection of the right power distribution architecture for a given application has a tremendous impact on the overall system in terms of efficiency, cost, reliability, fault tolerance and size. Moreover, with the increasing number of power sources, storage elements, different supply voltages and strong requirements imposed at system level, the selection of the appropriate architecture becomes a nightmare for the system designer. The purpose of this paper is to describe a methodology for the selection of the most suitable architecture for a fuel cell based power distribution application. The methodology is based on the assessment of metric functions for all the components that can configure the architecture as a function of the electrical boundary conditions of each component.

High voltage gain DC-DC converter for micro and nanosatellite electric thrusters

The increasing miniaturization in the satellite industry, together with the use of solar energy as main energy source has given rise to a new generation of electrically powered space probes. These new probes are featured by a small size and weight. In this paper, a DC-DC converter that adapts the energy produced by solar arrays to supply an electric thruster is proposed. This type of thruster demands high DC voltage, whereas the solar array gives out a low DC voltage with limited power. Hence, this converter must have high voltage gain and low power. A topology comprised of a step-up transformer, a resonant tank and a voltage multiplier in cascade is proposed to meet these requirements. In addition, an optimization study is made to spot a design criterion. Finally, a low scale prototype is tested and experimental results are shown.

Black-box model and identification methodology for PEM fuel cell with overshooted transient response

One of the power sources with most potential is fuel cells, especially in on-board applications. The design of a power distribution architecture based on fuel cells for transport applications is a complex task, due to the number and nature of the power converters, loads, secondary energy sources, etc. Modeling and simulation are essential design tools at system level. This paper proposes a complete fuel cell black box model, in order to reproduce the behavior of a commercial fuel cell with overshooted transient response. The model is parameterized by applying an identification methodology based on manufacturers datasheets and a test based on load steps. The fuel cell black-box model is validated experimentally using a commercial PEM (Proton Exchange Membrane) fuel cell.

Optimal sizing of propulsion systems applied to fuel cell based vehicles

The propulsion system implemented in a fuel cell based vehicle strongly affects the mass, cost and volume of the overall system. The design of a propulsion system architecture, which comprises different power converters and secondary energy storage systems, is closely related to the driving profile applied, since the power and energy requirements depend on the driving profile. This paper tackles the optimum sizing of the secondary energy storage systems, as well as the set of equations that describes the mass and cost of each one of the power train subsystems. After that, ten different propulsion systems are analyzed in order to determine which of them minimize the mass, cost and volume depending on the power delivered by the fuel cell.

System-level black-box modeling of DC-DC converters with input current control for fuel cell power conditioning

System-level modeling and simulation are powerful tools to evaluate the system-level behavior of new power distribution systems. However, due to confidentiality of manufacturers, black-box behavioral models of the converters are required instead of conventional ones. This paper proposes a black-box modeling method of DC-DC converters with input current control, oriented to fuel cells power conditioning. The model is simple and the identification procedure is based on straightforward experiments. The model does not represent the internal structure of the converter, thus maintaining manufacturers confidentiality. The method is validated using a commercial DC-DC converter for fuel-cells power conditioning.

Control strategy improvement for a parallel power distribution architecture based on fuel cells and supercapacitors

The use of fuel cells as main source of energy is suffering an important increase, due to their continuous improvements and their good performances. Fuel cells are being used in very different industrial applications, and they are being particularly applied in automotive field. So, there is an important growing in the study of new power distribution architectures based on fuel cells.