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

Abstract

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 number of the variable hydraulic pumps in real work; and a three-position four-way electromagnetic directional valve is used for controlling the type and the number of the variable hydraulic motors in real work. The method and device provided by the invention realize variable speed constant frequency power generation of a wind power generation device by regulating the displacement of the variable hydraulic pumps and the variable hydraulic motors, thus improving energy capture efficiency and achieving stable energy output of the generator.

Description

technical field [0001] The invention belongs to the field of wind power generation, and in particular relates to a variable speed and constant frequency method and device for wind power generation. Background technique [0002] In wind power generation, when the wind turbine is running in parallel with the grid, the frequency of the output wind power is required to be consistent with the frequency of the grid, that is, the frequency of the output wind power remains constant. Wind power generation includes two power generation methods: constant speed and constant frequency power generation and variable speed and constant frequency power generation. Among them, constant speed and constant frequency power generation refers to the electric energy that keeps the generator speed constant and the output frequency of the generator is constant during the process of wind power generation; Variable speed constant frequency power generation is a new type of power generation method deve...

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Problems solved by technology

The disadvantages of the above invention are: 1. After the variable hydraulic pump and the variable hydraulic motor in the ocean current power generation device are selected, the displacement adjustment accuracy and adjustment range of the variable hydraulic pump and the variable hydraulic motor are determined and cannot be changed; 2. If the change in seawater flow rate is small, the displacement adjustment accuracy of the determined variable hydraulic pump and variable hydraulic motor cannot adapt to the small change in seawater flow rate, and cannot guarantee the operation accuracy of variable speed and constant frequency; 3. If the change in seawater flow rate is large, The displacement of the variable hydraulic pump and the variable hydraulic motor needs to be greatly adjusted, which is beyond the determined range of displacement adjustment of the variable hydraulic pump and variable hydraulic motor, and the running accuracy of variable speed and constant frequency cannot be guaranteed.

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