Research On The Speed And Power Optimization Control In Hydraulic Type Wind Turbine

In recent years, the frequent occurrence of haze weather, serious air pollution does huge harm to human health, affecting the normal operation of social work. The worldwide energy crisis, reserves of coal, oil, natural gas and nuclear energy is increasing depletion. The use of new energy and renewable energy is imminent.Wind power as a kind of clean energy, wind energy is obtained mainly by the wind turbine, so it’s very important to rich the species of wind generator and optimize the control performance of wind turbine. Hydraulic transmission system are widely applied in aircraft, ships, excavators due to its large output torque, small volume, light weight, so it is very possible that the hydraulic system is used in wind power generation. The main drive system of the hydraulic wind turbine researched in this paper is a closed type hydraulic system of quantitative pump- variable motor. Compared with the traditional wind machine, small volume, light weight, hydraulic transmission is flexible transmission, and output power is easier for grid to accept. it is very important for the industrialization of the hydraulic wind turbine to optimize the control of the unit.In this paper, modern control theory is used to optimize the grid connected power speed control and the power tracking control in the hydraulic type wind turbine. the establishment of mathematical model of wind turbine, according to the control requirements to simplify it, studying on the nonlinear form of model, using the feedback linearization method to decouple the system, and then selecting the control strategy according to the control requirements of the grid connection and power tracking.In the aspect of grid speed control, the coordinated control system of the proportional flow valve and the variable motor swing angle was put forward. In the case of high wind speed, the proportional flow valve was used to control wind wheel rotational speed, to avoid system overflow increasing the workload of pump, improve the service life of the system. Based on the linearized model, finally the method was proposed, which is that the rotating speed of the wind wheel was controlled by a proportional flow valve, and the entrance pressure of the motor was controlled by the swing angle of variable motor, using the Lyapunov energy function to determine the control reference value, realizing the variable motor working in frequency rotational speed thus wind turbine smooth gridIn the aspect of max power point tracking, use the best speed and optimum power as the control targets, based on the feedback linearization method to solve the control laws, use simulation to compare the static and dynamic response characteristics of the system between the two strategies. Analyze the reason of power fluctuations in the control process of power tracking. Finally choose the control scheme with power output as the control target.Simulation validation is through the establishment of simulation model in Matlab/Simulink, and the proposed control strategy was verified in the 30 KVA semi physical simulation experimental platform. Simplify the control theory according to engineering demand and verified in the platform. Simulation and experimental results show that, the control method proposed in the paper can achieve the expected effect.