Dynamic Modelling and Analysis of a Hydraulic Energy Storage Based Hybrid Power Transmission for Wind Turbine

This work discussed the detailed dynamic model of a Hydraulic Energy Storage based Hybrid Power Transmission (HESbHPT) technology.It is an unite operation of two individual power transmission systems, such as gear train and a state-of-art hydraulic energy storage-based hydraulic power transmission.The output power of the turbine rotor is applied as the input power of the gear train whereas the output power of the gear train is supplied to the hydraulic pump that supplies flow to the hydraulic motor of the hydraulic power transmission (HPT).A hydraulic energy storage, i.e., an accumulator and two control valves are incorporated between the hydraulic pump and the motor in order to operate the fixed load by storing or releasing the excess flow supplied from the pump.A Two-step or On-Off controller controls the control valves and ensures the charging and discharging operation of the accumulator.The dynamic bond graph model of the HESbHPT is developed and simulated using SYMBOLS SHAKTI software.The simulation responses of the proposed model indicate that the output speed of the hydro-motor is stable to 8.2 rad/s although the input power to the gear train is variable in nature.Also, the efficiency of the HESbHPT is reported, and found that the overall transmission efficiency is in the range of 90-98%.Moreover, the pressure and energy storage variation into the accumulator is reported.