Abstract: A wind power generation system design based on power-split type Hydro-mechanical continuously variable transmission ( HMCVT) was proposed，aiming at the problem of variable speed constant frequency ( VSCF) in wind power generation system． The system combines high-power density and stepless speed regulation in hydraulic circuit and high efficiency in mechanical circuit by means of power-split． Firstly，the static speed regulation and efficiency characteristics were analyzed theoretically on the premise of variable speed input and constant speed output． Secondly，modeling，dynamic simulation and analysis were carried out for the HMCVT wind power system by Matlab/Simulink，combining with the practical working conditions． Additionally，the controller based on fuzzy PID was established，which enabled it to control the output speed rapidly and accurately． Finally，the speed regulation characteristics of the transmission prototype was investigated on the comprehensive test platform． The simulation and experimental results show that the HMCVT technology provides a solution to VSCF problem for wind power generation system between the wind speed range of cut-in and cut-out． Moreover，it has swift dynamic property with the efficiency around 87%． 

Key words: wind power generation, variable speed constant frequency ( VSCF) , hydro-mechanical continuously variable transmission ( HMCVT) , power-split