Research Of A Wind Turbine With Hydraulic Transmission Based On Digital Displacement Pump

The high wind speed and the large potential for development make the offshore wind power occupy an important position.The cabin of traditional wind turbine is very heavy,which greatly increases the weight of tower and foundation,resulting in a significant increase in the construction cost of offshore wind farm.The wind turbine with hydraulic transmission can reduce the weight of the cabin by transferring the generator to the platform.But there are some problems such as the torsion of the hydraulic pipeline during yawing,low efficiency of swash plate variable displacement pump under partial load.In this paper,a hydraulic driven wind turbine using digital displacement pump as energy conversion component is designed,and the operation mode of the wind turbine is planned,provide a new solution for reducing the cost of offshore wind farm.By analyzing the working principle of the wind turbine with hydraulic transmission,a mode of the pump placed in the tower by the bevel gear transmission is proposed.and the mathematical model of the energy conversion process of the wind turbine is established.The influence of relevant parameters on the steady flow fluctuation of the accumulator is studied.The key parameters of the wind turbine is calculated in vase of a rated power of 1.5 MW.A mechanical structure of the digital displacement pump is designed,the cylindrical cam drives multiple sets of plunger cylinder modules.The high-speed electromagnetic on-off valve and the check valve are used to distribute the flow of the plunger pump module,and a flow control method is proposed.A digital displacement pump simulation model is constructed and the dynamic response of the digital pump is analyzed.The results show that with the increase of the displacement coefficient,the flow and the anti-torque of digital displacement pump all show a “stepped” increase,and pulsing near the theoretical flow and the theoretical torque.After the output flow of the digital pump is stabilized by the accumulator,the flow fluctuation is greatly attenuated.According to the effective wind speed region of the wind turbine,a operation mode of wind turbine in different wind speed regions is proposed.The problem of low power efficiency of generator is avoided by intermittent power generation;When the wind speed is high,the wind turbine generates electricity continuously,and the accumulator stabilizes the motor output power;When the wind speed is high and the power demand is small,the motor maintains the output power constant,the accumulator absorbs excess energy.A method of maximum power point tracking for hydraulic wind turbine based on digital displacement pump is studied: By detecting the wind speed,the effective displacement of the digital displacement pump is adjusted to make the wind turbine run near the optimal speed.The model of hydraulic transmission wind power generation system was established by Matlab/Simulink and AMEsim.The operating characteristics of the wind turbine in different working modes were obtained,and the correctness of the overall scheme of wind turbines was verified.