Felix A. Farret

An electrochemical-based fuel-cell model suitable for electrical engineering automation approach

This paper presents a dynamic electrochemical model for representation, simulation, and evaluation of performance of small size generation systems emphasizing particularly proton exchange membrane fuel-cell (PEMFC) stacks. The results of the model are used to predict the output voltage, efficiency, and power of FCs as a function of the actual load current and of the constructive and operational parameters of the cells. Partial and total load insertion and rejection tests were accomplished to evaluate the dynamic response of the studied models. The results guarantee a better analytical performance of these models with respect to former ones with a consequent reduction in time and costs of projects using FCs as the primary source of energy. Additionally, this electrochemical model was tested for the SR-12 Modular PEM Generator, a stack rated at 500 W, manufactured by Avista Laboratories, for the Ballard Mark V FC and for the BCS 500-W stack.

Dynamic simulation and analysis of parallel self-excited induction generators for islanded wind farm systems

In this paper, a dynamic mathematical model to describe the transient behavior of a system of self-excited induction generators (SEIGs) operating in parallel and supplying a common load is proposed. Wind turbines with SEIGs are increasingly being used to generate clean renewable energy in rural areas owing to many economical advantages. Parallel operation of SEIGs is required where the size of the machine is a constraint. SEIGs connected in parallel experience various transient conditions such as generator/load/capacitor switching that are not easy to simulate using conventional models. An automatic numerical solution to predict the steady-state and transient behavior of any number of SEIGs connected in parallel is proposed in this paper. The generators can be of different ratings and can have different prime mover speeds. The performance of the proposed model when subjected to various dynamic scenarios is compared with experimental results. The simulation results are in good agreement with the experimental results, confirming the validity of the proposed model. An aggregated model of a small wind power system is also proposed. This model was applied to a two-wind turbine case, which can be extended to simulate a complete wind generating system.

Appendix C: The Stirling Engine

This appendix contains sections titled: Introduction Stirling Cycle Displacer Stirling Engine Two-Piston Stirling Engine References ]]>

Appendix B: Geothermal Energy

This appendix contains sections titled: Introduction Geothermal as a Source of Energy References