Dynamic Load Calculation Of The Variable-speed Variable-pitch Wind Turbine Transmission System

With economic development, the energy requirement is on the increase. However,the conventional energy, such as oil, coal, natural gas and other fossil fuels, arenonrenewable energy, and its reserves are limited in the earth. Because of its excessiveconsumption in the past decades, the conventional energy is becoming more shortagesnow. Wind energy as an ideal renewable energy, has attracted the attention of the wholeworld. The governments around the world have invested huge resources for the windpower research.Variable speed and variable pitch wind turbine is able to more effectively to utilizethe wind power from the wind farm, and its output power is more stable. It has been themainstream type of moderm large scale wind turbine. Wind turbine running at thecomplicated natural environment, and with the changing of the wind speed, the windturbine automatically regulate its rotor speed and pitch angle, all of these make thedynamic loads of transmission system of the variable speed and variable pitch windturbine very complicated. And the dynamic loads of the transmission system is seriouslyinfluence the design of the key components of the wind turbine, such as the increasinggearbox. So the dynamic loads of the variable speed and variable pitch wind turbinetransmission system are calculated and analyzed in this dissertation, and thisdissertation mainly do the following works:①The aerodynamic loads is the main effect factors to the dynamic loads of thewind turbine transmission system. So the unsteady aerodynamic loads calculation modelis established in this dissertation. The dynamic inflow, dynamic stall, stall delay and soon correction model is included in this model, so that the calculation result more in linewith the actual wind turbine aerodynamic condition.②The dynamic respond models, such as the blade, tower, transmission system,generator, variable speed and variable pitch control system and the brake system, areestablished in this dissertation. By combining these models and the unsteadyaerodynamic loads model, it is able to make the wind turbine transmission systemdynamic loads calculation model to be more complete and its calculation results to bemore precise.③The particle swarm optimization (PSO) algorithm is studied in this dissertationto get the proper parameters for the blade aerodynamic shape and all the PI and PID controller in the variable speed and variable pitch control system. Then the optimizationresults are analyzed to verify the rationality of the optimization results.④With the wind turbine transmission system dynamic loads calculation modelthat establish in this dissertation, the wind turbine running characteristics are analyzedto verify the rationality of the calculation model. Then the dynamic loads of the windturbine transmission system are calculated and its characteristics are analyzed. From thecalculation results, the variation regulations and its effect factors of the geartransmission system’s input loads are obtained. The results lay the foundation for thestudy of the dynamic and reliability of the gear transmission system of wind turbine.