| The global economy has accelerated the consumption of energy, including coal, oil,natural gas and other non-renewable energy occupied a dominant position in China’s energy structure. Excessive energy consumption accelerated the depletion of fossil fuels and not conducive to the sustainable development of energy. While extensive use of fossil fuels inevitably produce harmful substances to environment such as carbon dioxide, and it has adversely affect health on people’s lives. As a clean, renewable energy, more and more people pay attention to the wind. In addition to hydropower, the wind is the most valuable development and utilization of renewable energy. The main methods are grid-connected and off-grid to use of wind energy. Small wind turbines either as a standalone system provides electricity to the user’s production and life or as a distributed network systems transmission of electricity for the grid.5k W wind turbine has been widely used, because it has a lot of advantages, such as capacity suitable for easy transportation maintenance and small footprint. In order to make the wind turbine output frequency with the user desired frequency or grid frequency compatible, wind turbines are generally added a complex system commutation between wind turbines to the grid in production applications. This system increases the current harmonic components,increases the frequency control of electric energy consumption, increased the failure rate of the generator and reduces the reliability of the generator. To achieve high reliability,small wind generators must reduce complexity and poor reliability commutation system,so research a high wind energy utilization constant speed wind variable pitch turbine is very necessary.First, this article designed and calculated the aerodynamic shape of wind wheel by Wilson design method, and analyzed the pitch principle of 5k W wind turbines in operation based on blade element theory, and proposed method for calculating the amount of the pitch angle adjustment at different wind speeds. Then calculate the blade shape parameters and the volume adjustment of pitch angle by MATLAB software. And converting the two-dimensional coordinates into three-dimensional coordinates according to the principle of coordinate transformation. Build wind turbine model in Gambit software. Third, using Ansys software to numerical simulation the aerodynamic characteristics of wind wheel. Simulated wind turbine power output the power outputcharacteristics of wind wheel under fixed blade running and pitch running. Finally,produced experimental physics of wind wheel based on similarity theory. Verified the power performance of the wind wheel by vehicles-carried experiment in the wild.This paper studies the operating characteristics of the constant-speed pitch wind turbine, and obtained the following results.1.When the wind speed is less than the rated wind speed, the correspondence between best pitch angle and wind speed of variable pitch wind turbine in order to maximize the utilization factor of wind turbines.2.When the wind speed exceeds the rated wind speed, the relationship between pitch angle adjustment and wind speed in order to maintain the stability of the wind turbine power output.3.Got wind wheel power output characteristics under the pitch conditions by numerical simulation.4. Verified physical variable pitch wind turbine output characteristics under fixed pitch condition and variable pitch condition by vehicles-carried experiment. |
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