Variable speed constant frequency method for wind power generation and device thereof

The invention belongs to the field of wind power generation, particularly to a variable speed constant frequency method for wind power generation and a device thereof; the variable speed constant frequency method obtains signals of wind speed, rotating speed of a wind wheel and the rotating speed of a generator by monitoring, and inputs the signals to a PLC (Programmable Logic Controller) controller; the PLC controller calculates according to certain control algorithm and outputs displacement control signal to regulate the displacement of variable hydraulic pumps and variable hydraulic motors, thereby regulating the rotating speed of the wind wheel to follow the wind speed to operate at variable speed, and regulating the generator to operate at constant frequency; the variable speed constant frequency device comprises a wind wheel, two variable hydraulic pumps, two variable hydraulic motors and a generator; a three-position three-way electromagnetic directional valve is used for controlling the type and the n