Nonlinear state space model of a hydraulic wind power transfer

Nonlinearities in gearless hydraulic wind power transfer are originated by operation of discrete elements such as check valves, proportional and directional valves, and leakage factor of hydraulic pumps and motors. Nonlinearities cause behavioral change in the system. This paper introduces a nonlinear state space representation of a hydraulic wind energy transfer system. A rate-limit controller is designed to regulate the proportional valve position to maintain the primary motor´s reference angular velocity. The performance of the controller is verified with simulation results. The simulation response demonstrates accurate modeling of the system operation and close tracking of the reference angular velocity profile.