Research On Independent Variable Pitch Electro-hydraulic System Of Tidal Current Turbine

Due to the increase in energy consumption and the pressing social expectations,tidal current energy faces many challenges in the development and application.When the tidal current turbine works,if the water flow velocity exceeds the rated flow rate,the power can be output stably through pitch control.However,the different loads on the blades during the collective pitch process cause the multi-blade movement process to be out of synchronization,which will cause the imbalance of the impeller and affect the safe operation of the turbine.In this paper,a 650 k W tidal current turbine is taken as the research object,and a new pitch system combining the pre-valve compensation and proportional control technology is designed to achieve individual pitch control,focusing on the problem of multi-blade synchronous motion in the collective pitch mode,the feasibility of the scheme is verified by amesim simulation.The main contents of each chapter of the paper are as follows:The first chapter introduces the research background of the subject,summarizes the current status of domestic and foreign tidal current turbine and the research on pitch technology through literature research,and proposes a phenomenon that the blade movements are not synchronized during the collective pitch process have an impact on safe operation of the turbine,the application of the hydraulic synchronous control system in construction machinery and equipment is introduced,and the significance and content of the research are elaborated.The second chapter introduces the principle and characteristics of pitch control,analyzes the blade load,and lays a theoretical foundation for the calculation of the pitch torque.The design load condition table is developed based on the operating conditions that may be encountered during the operation of the ocean current generator set,and take the 650 k W turbine as the research object to carry out full load analysis and calculation.The third chapter firstly proposes a preliminary pitch scheme,and optimizes the existing problems of the scheme.The feasibility of the design is demonstrated through simulation.Finally,a new pitch system combining pre-valve compensation and proportional control is proposed.The fourth chapter performs mathematical modeling and analysis on the position control system of the valve-controlled motor pitch,establishes a simulation model of the proportional control system with pre-valve compensation,analyzes the dynamic performance about collective pitch and individual pitch.The effect of parameter changes on the synchronization accuracy of multi-blade movements is proposed.Then a fuzzy cross-coupling synchronization control strategy is proposed.It is verified by simulation that the strategy can meet the requirements of synchronization accuracy on the premise of ensuring the response speed of single blade pitch.The fifth chapter designs the hydraulic test bench according to the previously proposed pitch scheme,focuses on the research and analysis of the pitch load loading system,selects the main hardware,and uses Lab VIEW as the upper computer virtual software platform to pitch the test bench.The system carried out a preliminary scheme design.The six chapter summarizes the research work of the subject and looks forward to further research directions.