A feasibility and dynamic performance analysis of hydromechanical hybrid power transmission technology for wind turbines

A multi-body dynamical model of a wind turbine power generation system (WTPGS) based on hydromechanical hybrid power transmission (HMHPT) technology is developed and simulated to overcome the individual drawbacks of the gear train and hydrostatic power transmission (HPT) system. The HMHPT is a hybrid concept of a single-stage planetary gear train (SSPGT) and a typical HPT. The input shaft of the SSPGT is coupled with the turbine rotor, whereas the output shaft of the SSPGT is coupled with the shaft of a hydraulic pump. The hydraulic pump supplies flow to the hydro-motor, and its shaft is coupled with the generator. An existing turbine blade model of 750 kW based wind turbine is used for further development and analysis of the HMHPT. The simulation responses indicate that the power generation and the control potential both have been improved using the HMHPT in a wind turbine. Moreover, the influence on the motor power generation due to variations of pump and motor leakages is addressed. Additionally, it is found that if the order of the SSPGT and the HPT are swapped in the proposed HMHPT, then the settling time, maximum overshoot, and rise time of the system responses are increased. As a result, the controllability of the system is decreased.