Research On The Grid Connected Control In The Parallel Generator Of The Turbine With Hydraulic Transmission

With the rapid development of wind power industry in recent years, it plays animportant role in the mitigation of enxironmental and energy crisis. As a new type of thewind turbine, compared with the traditional model, the wind turbine with hydraulictransmission has advantages of a higher power-to-weight ratio and the real-timeadjustment to the speed ratio. It also eliminates the need for the inverter and box-typetransformer, so it greatly reduces the weight and the cost of the wind turbine. Therefore,the research of the key hydraulic wind turbine technology has practical significance.Generally two or more generators are connected in parallel to generate power to meetthe greater power requirements. The parallel generators system of the hydraulic drive windturbine, as the topic of this paper, has been studied by doing theoretical analysis and theexperimental research. By starting from the characteristics of wind, wind turbine andhydraulic-drive system of the fixed-displacement pump/variable motor, we studied boththe speed control method and the pressure control method when the grid connected.In the analysis of the fixed-displacement pump/variable motor system characteristics,we used the small signal linearization method to solve problems of multiplying nonlinear,and proposed a high pressure control method based on structure invariance compensation,which solved the issues of mutual coupling between the two variable motor angle and thehigh pressure. Then we proposed the high pressure control strategy when the gridconnected and speed control technologies.AMESim software is employed to construct a simulation model of the hydraulicsystem. The wind model, the wind turbine model and system high pressure and parallelmotor speed control methods are modeled by the simulation software MATLAB/Simulink.The two softwares co-simulation is completed with the interface technology. The paperestablishes the hydraulic parallel wind turbine generator overall simulation model to studythe parallel generator grid connected control strategy applicability of the hydraulic windturbine. Based on both theoretical and simulation analysis, a24kW hydraulic drive windturbine experimental platform is built. Through the experimental platform, it verifyed the feasibility of hyperbaric pressure control and parallel motor speed control of the system.The research lays the foundation for carrying out the research of the hydraulic windturbines parallel generator grid connected speed control.