Study of the applied technology of hydraulic speed variation and transmission for wind power generation systems

The authors have analyzed the working principle of a hydraulic tortjue converter used for a wind power generation system to realize speed variation and constant frequency. To secure maximal wind power with a comprehensive consideration of the structural parameters of a mechanical transmission system, determined was the output speed regulation range of the hydraulic torque converter, capable of accommodating to any change of wind-wheel rotating speed and keeping a generator operating at a constant speed. On the basis of the torque balancing relationship of the transmission system and in conjunction with the torque-speed characteristics of a windmill rotor, the input power of a pump wheel has been calculated. Herefrom, the characteristic geometric parameters of the hydraulic torque converter was tentatively ascertained. From an energy balance equation, the efficiency of the whole transmission system was evaluated. The above research has laid a theoretical and analytic basis for the popularization of hydraulic transmission in wind power generation systems.