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a b s t r a c tThis paper focuses on dynamic modeling, simulation, control and energy management in an isolated integrated power generation system consisting of a 315 kW offshore wind turbine, a 175 kW tidal turbine, a 290 kW microturbine, and a 3.27 kAh lead acid battery storage. A first, due to efficient and economical utilization of the renewable energy resources, optimal sizing of the hybrid system is accomplished based on economic analysis using genetic algorithms. A model of power-consumption for a microturbine is obtained using least square estimation algorithm based on capstone™ company data and is suggested for implementing at economic analysis. For extraction of maximum energy from a variable speed wind turbine, a developed Lyapunov model reference adaptive feedback linearization method accompanied by an indirect space vector control is applied. Because of more reliability, more fuel flexibility, less environmental pollution, less noise generation and less power fluctuation in comparison with a diesel generator, a microturbine integrated with battery storage is suggested as a back up for this system.A supervisory controller is designed for energy management between the maximum energy captured from the wind turbine and consumed energies of the load, dump load, energy of the battery based on state of charge and generated energy by the microturbine. Dynamic modeling and simulation are fulfilled using MATLAB Simulink™7.2.

Power quality was always a major concern in designing an electric supply system for railways. Since electric railcars are usually single-phase loads, they draw high amounts of negative sequence component of currents, in addition to harmonic contents and transient currents. Therefore, many compensation methods were examined to improve the power quality indices. The active power quality conditioner (APQC) can be considered as an ideal compensator for high-speed railway, which contains a three-phase converter connected to the traction substation through a step-down transformer. However, with the growth of railway loads, the nominal rating of the solid-state high-frequency switches of APQC increases seriously, which in turn, results in an exponential growth of the cost of power-electronic switches. Therefore, for a very high-capacity railway system, it is not economic to apply an APQC. As a solution, a combination of APQC with the static VAr compensator is proposed in this study, which reduces the rating of APQC, and improves the power quality of the system. Simulation results validate the pre-defined hypothesis. Moreover, the performance of APQC depends on the DC-link operation, for which genetic-algorithm optimisation has been applied to obtain an optimum design of a stable DC-link voltage.

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