This paper presents a new operational strategy for a small scale wind farm which is composed of both fixed and variable speed wind turbine generator systems (WTGS). Fixed speed wind generators suffer greatly from meeting the requirements of new wind farm grid code, because they are largely dependent on reactive power. Integration of flexible ac transmission systems (FACTS) devices is a solution to overcome that problem, though it definitely increases the overall cost. Therefore, in this paper, we focuses on a new wind farm topology, where series or parallel connected fixed speed WTGSs are installed with variable speed wind turbine (VSWT) driven permanent magnet synchronous generators (PMSG). VSWT-PMSG uses a fully controlled frequency converter for grid interfacing and it has abilities to control its reactive power as well as to provide maximum power to the grid. Suitable control strategy is developed in this paper for the multilevel frequency converter of VSWT-PMSG. A real grid code defined in the power system is considered to analyze the low voltage ride through (LVRT) characteristic of both fixed and variable speed WTGSs. Moreover, dynamic performance of the system is also evaluated using real wind speed data. Simulation results clearly show that the proposed topology can be a cost effective solution to augment the LVRT requirement as well as to minimize voltage fluctuation of both fixed and variable speed WTGSs.Index Terms-Frequency converter, low voltage ride through (LVRT), multilevel converter/inverter, permanent magnet synchronous generator (PMSG), voltage source converter (VSC), wind generator.

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This paper presents a combination system of wind energy conversion and hydrogen production. Hydrogen is expected as an alternative energy source in the future, and this is the best way to produce it from renewable energy like wind energy. On the other hand, the output of a wind generator, in general, fluctuates greatly due to wind speed variations, and thus the output fluctuations can have a serious influence on the power system operation. In the proposed system, a variable speed wind generator is adopted, and an electrolyzer is installed in parallel with it for hydrogen production. Output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer based on the cooperative control method. The performance of the proposed system is evaluated by simulation analyses, in which simulations are performed by using PSCAD/EMTDC. Index Terms-Hydrogen production, power smoothing, variable speed wind generator, wind energy conversion.

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A microreaction system for organic photoreactions was developed, and the processes of diastereo-differentiating photosensitized reaction, photocatalytic oxidation and reduction of organic compounds, and amine N-alkylation were examined in microspace. These model reactions proceeded very rapidly with considerably large photonic efficiencies because of some distinct properties of microreactors for photoreactions, such as higher spatial illumination homogeneity and better light penetration through the entire reactor depth, and large surface-to-volume ratio in comparison with large-scale batch reactors. These results suggest feasibility of microreaction systems on organic photoreactions.

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This paper proposes a fuzzy-logic-controlled superconducting magnetic energy storage (SMES) scheme for the stabilization of grid-connected wind-generator systems. The control scheme of SMES is based on a sinusoidal pulsewidth-modulation voltage-source converter and a two-quadrant dc-dc chopper using an insulated-gate bipolar transistor. A comparative study is carried out between the proposed fuzzy-logic-controlled SMES and the fuzzy-logic-based pitch controller to improve the windgenerator stability. Simulation results demonstrate that the performance of the proposed fuzzy-logic-controlled SMES is better than that of the fuzzy-logic-based pitch controller in order to stabilize the wind generator.Index Terms-Fuzzy-logic controller, pitch controller, superconducting magnetic energy storage (SMES), unsuccessful reclosing, voltage-source converter (VSC), wind-generator stability.