| With the rapid economical development, the shortage of energy become a globalproblem. The ore energy is exhausting. How to use renewable energy effectively is aresearch hotspot. In this paper, a novel wind turbine with hydraulic transmission ismainly discussed and studied. Expensive wind power converter and heavy gear boxthat used in traditional wind turbine technology are eliminated in the system, whichleads up to a lower costs, it is also easy to assemble and maintain the top nacelle.Therefore, The research on hydraulic transmission is great significant, the advantagewill be particularly obvious in offshore wind power generation system.This paper analyzes the components and the working principle of wind powerwith hydraulic transmission system. The control strategies of system starting andconnecting to grid, owe power operation and rated power operation was proposed forthe wind turbine with hydraulic transmission, and focus on the hydraulic motor rotorspeed precise control of grid-connecting with synchronous generator. The dynamicsmodel of rotor speed control system is built.According to the high order model of hydraulic motor rotor speed control system,the backstepping controller was designed. The adaptive laws are designed to estimatethe uncertain parameters present in the hydraulic motor system and external loaddisturbance. The convergence was proved with Lyapunov stability theory. Thesimulation results show that the controller works fast with responsibility and highrobustness.On the basis of the above study, the model states of the hydraulic motor rotorspeed system are transformed. The uncertain parameters present in the system andexternal load disturbance are considered in whole. A second order extended stateobserver is designed to estimate the acceleration signal of the hydraulic cylinder whichis difficult to measured, and the disturbance in whole of servo valve controlledcylinder system. The backstepping controller is simplified. Simulation resultsdemonstrate the effectiveness of the proposed method. |
