Method for optimum controlling for electric transmission system of low-speed direct-drive wind turbine generator

Abstract

The invention discloses a method for controlling efficiency of an electric transmission system of a low-speed direct-drive wind turbine generator. The method comprises the following steps of (1) preestablishing a total loss model of the electric transmission system of the wind turbine generator, wherein the total loss model comprises a generator loss submodel and a converter loss submodel which are respectively established according to the stator voltage and running rotation speed of the generator; (2) when the control is executed, inputting initial power to control the running of the target wind turbine generator; (3) adjusting the stator voltage and running rotation speed of the generator, minimizing the loss of the generator calculated according to the generator loss submodel, and minimizing the total loss calculated according to the main loss model, so as to control the target wind turbine generator to run according to minimum total loss. The method has the advantages that the realizing method is simple, the required cost is low, the high-efficiency power generation in the full-power running range is realized, and the control efficiency is high.

Description

technical field [0001] The invention relates to the technical field of control of low-speed direct-drive wind turbines, in particular to a method for optimally controlling the efficiency of an electric transmission system of a low-speed direct-drive wind turbine. Background technique [0002] At present, the key technical indicators of wind turbines are power generation performance and reliability, and power generation performance, as the most concerned indicator of wind turbine operators, directly affects the market prospect of wind turbines. A low-speed direct-drive wind turbine (DDWT) is a wind turbine that is directly driven by a wind turbine to run a generator, and the generator is directly connected to the grid through a full-power converter. For low-speed direct-drive wind turbines, because the generator is directly driven by the wind wheel, the gearbox and high-speed coupling are omitted, and the transmission loss during operation is mainly the loss of the electric d...

AI Technical Summary

Problems solved by technology

For the above-mentioned existing control methods, when the wind turbine is in the small wind stage, since the mechanical power input from the wind rotor to the generator is small, the loss of the electric drive system accounts for a large proportion of the total power. At the same time, in the small wind stage, The deviation between the actual speed of the wind turbine and the optimal speed has little effect on the mechanical power input by the generator. Therefore, in the existing control mode, only the optimal speed of the wind turbine is tracked (the generator’s input mechanical power is optimal) as Control objectives, while ignoring the optimal control of the electrical efficiency of the electrical drive system, resulting in the overall efficiency of the wind turbine in the small wind stage is not high

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