No description available.

In a Doubly-fed Induction Generator (DFIG) wind energy conversion system, the rotor of a wound rotor induction generator is connected to the grid via a partial scale ac/ac power electronic converter which controls the rotor frequency and speed. In this research, detailed models of the DFIG wind energy conversion system with Sinusoidal Pulse-Width Modulation (SPWM) scheme and Optimal Pulse-Width Modulation (OPWM) scheme for the power electronic converter are developed in detail in PSCAD/EMTDC. As the computer simulation using the detailed models tends to be computationally extensive, time consuming and even sometimes not practical in terms of speed, two modified approaches (switching-function modeling and average-value modeling) are proposed to reduce the simulation execution time. The results demonstrate that the two proposed approaches reduce the simulation execution time while the simulation results remain close to those obtained using the detailed model simulation.

China is an energy production and consumption country, wind power is one of the greatest development potential energy.The authors use literature research methodology, case study, comparative study and trend analysis study to analysis current condition of the breeze wind power.China has a long history of wind development, use wind power to generate electric is only developed in recent years, but it is expanding fast. China is a country covering vast territory, and it is rich in wind resources. But some reasons such like natural, economy, environmental etc, limit the wind power development of China.The VAWT is a new kind of wind driven generator, it has many advantages that HAWT doesn’t have. Utilize VAWT to develop breeze wind power generation, will bring wind power into more families.

In order to support large-scale integration of wind power into current electric energy system, accurate wind speed forecasting is essential, because the high variation and limited predictability of wind pose profound challenges to the power system operation in terms of the efficiency of the system. The goal of this dissertation is to develop advanced statistical wind speed predictive models to reduce the uncertainties in wind, especially the short-term future wind speed. Moreover, a criterion is proposed to evaluate the performance of models. Cost reduction in power system operation, as proposed, is more realistic than prevalent criteria, such as, root mean square error (RMSE) and absolute mean error (MAE). Two advanced space-time statistical models are introduced for short-term wind speed forecasting. One is a modified regime-switching, space-time wind speed fore- casting model, which allows the forecast regimes to vary according to the dominant wind direction and seasons. Thus, it avoids a subjective choice of regimes. The other one is a novel model that incorporates a new variable, geostrophic wind, which has strong influence on the surface wind, into one of the advanced space-time statistical forecasting models. This model is motivated by the lack of improvement in forecast accuracy when using air pressure and temperature directly. Using geostrophic wind in the model is not only critical, it also has a meaningful geophysical interpretation. The importance of model evaluation is emphasized in the dissertation as well. Rather than using RMSE or MAE, the performance of both wind forecasting models mentioned above are assessed by economic benefits with real wind farm data from Pacific Northwest of the U.S and West Texas. Wind forecasts are incorporated into power system economic dispatch models, and the power system operation cost is used as a loss measure for the performance of the forecasting models. From another perspective, the new criterion leads to cost-effective scheduling of system-wide wind generation with potential economic benefits arising from the system-wide generation of cost savings and ancillary services cost savings. As an illustration, the integrated forecasts and economic dispatch framework are applied to the Electric Reliability Council of Texas (ERCOT) equivalent 24- bus system. Compared with persistence and autoregressive models, the first model suggests that cost savings from integration of wind power could be on the scale of tens of millions of dollars. For the second model, numerical simulations suggest that the overall generation cost can be reduced by up to 6.6% using look-ahead dispatch coupled with spatio-temporal wind forecast as compared with dispatch with persistent wind forecast model.

Wind energy systems are being closely studied because of its benefits as an environmentally friendly and renewable source of energy. Because of its unpredictable availability, power management concepts are essential to extract as much power as possible from the wind when it becomes available. The purpose of this thesis is to presents a new adaptive control algorithm for maximum power point tracking (MPPT) in wind energy systems. The proposed control algorithm allows the generator to track the optimal operation points of the wind turbine system under fluctuating wind conditions and the tracking process speeds up over time. This algorithm does not require the knowledge of intangible turbine mechanical characteristics such as its power coefficient curve, power characteristic or torque characteristic. The algorithm uses its memory feature to adapt to any given wind turbine and to infer the optimum rotor speeds for wind speeds that have not occurred before. The proposed algorithm uses a modified version of Hill Climb Search (HCS) and intelligent memory to implement its power management scheme. This algorithm is most suitable for smaller grid or battery connected wind energy systems. PSIM simulation studies have been done to confirm the effectiveness of the proposed algorithm. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-12-15 20:47:44.884

No description available.

No description available.

In a Doubly-fed Induction Generator (DFIG) wind energy conversion system, the rotor of a wound rotor induction generator is connected to the grid via a partial scale ac/ac power electronic converter which controls the rotor frequency and speed. In this research, detailed models of the DFIG wind energy conversion system with Sinusoidal Pulse-Width Modulation (SPWM) scheme and Optimal Pulse-Width Modulation (OPWM) scheme for the power electronic converter are developed in detail in PSCAD/EMTDC. As the computer simulation using the detailed models tends to be computationally extensive, time consuming and even sometimes not practical in terms of speed, two modified approaches (switching-function modeling and average-value modeling) are proposed to reduce the simulation execution time. The results demonstrate that the two proposed approaches reduce the simulation execution time while the simulation results remain close to those obtained using the detailed model simulation.

The focus of the research program is to analysis and design of a new generation glass-fibre reinforced polymer (GFRP) wind turbine tower for full scale prototype testing. The study includes the finite element analyses of different tower section configurations, the parametrical study of different variables, the selection of appropriate configuration and dimensions, and the finalization of the section. The design section arrived from this study has the bottom outer diameter of 1350 mm, the top outer diameter of 800 mm, the constant inner diameter of 600 mm and uniform wall thickness of 11.25 mm. The tower is also analysed and compared with a steel tapered tower. The analysis results indicate that the tower is considered as a soft-soft tower and that, in general, the lateral deflection limitation is a governing factor in the design of GFRP wind turbine tower. The proposed section met all the design requirements and the fabrication drawings are provided for the further study of full scale test.

In 2004 a post-frame structure with plastered straw bales as an in-fill wall system was built at the University of Manitoba. Load cells installed at the top and bottom of ten eave wall posts were intended to measure the tributary load transferred from the roof structure into the supporting posts. In 2011 wind speed and direction were measured adjacent to the structure and correlated to simultaneous load data. A linear regression model relating load to wind speed within four directional quadrants revealed that load behaviour was inconsistent with design-level loading prescribed by the National Building Code of Canada (2005). A second regression model with both speed and direction as independent variables did not determine any statistically significant relationships. This research concluded that the initial assumptions made in 2004 required additional scrutiny, including the conditions under which the load cells were calibrated, and the structural contribution of the walls’ plastered skins.