Maximum available torque weak magnetic control method for permanent-magnet direct-drive wind turbine

Abstract

The invention relates to the field of wind power generation, and specifically relates to a maximum available torque weak magnetic control method for a permanent-magnet direct-drive wind turbine. The method is characterized by comprising the following steps: obtaining a maximum wind energy tracking designing curve of the permanent-magnet direct-drive wind turbine: T<e><0>=MPPT(omega<t>), under a given rotating speed omega<t>, by taking a direct-axis current and a cross-axis current i<d> and i<q> as optimization variables, solving a constrained optimization problem in an off-line mode, taking i<dpt> and i<qpt> as the optimization variable solutions of the optimization problem, and obtaining weak magnetic currents of the maximum available torque weak magnetic control method, given i<d><0>=i<dpt>; changing a rotor rotating speed omega<t> by taking a proper step length delta omega<t>, i.e., enabling omega<t>= omega<t>+delta omega<t>; and connecting a series (omega<t>, i<d><0>) of points to form a curve so as to obtain a weak magnetic current given curve i<d><0>=MAT(omega<t>) under various rotating speeds. According to the particularity of wind turbine control, i.e., the overall control strategy of the turbine enables the torque instruction of a permanent-magnet synchronous generator and a current rotating speed to be in a one-to-one corresponding relationship, possibility is provided for simplifying the design of the weak magnetic controller of a wind turbine.

Description

technical field [0001] The invention relates to the field of wind power generation, in particular to a maximum available torque field weakening control method for permanent magnet direct drive wind turbines. Background technique [0002] Permanent magnet direct drive wind turbines have been widely used in the field of wind power generation because of their compact structure and reliable performance. Megawatt-class large-capacity permanent magnet direct drive units generally use full-power back-to-back converters as the drive unit of permanent magnet synchronous motors. In order to capture more wind energy, when the wind speed is high, the operating speed of the permanent magnet synchronous generator is also high, which in turn makes the induced electromotive force of the generator also high. Due to the limited DC bus voltage of the back-to-back converter, if the electromotive force induced by the stator of the generator is too high, the generator cannot output enough active...

AI Technical Summary

Problems solved by technology

[0010] In order to overcome the problems that the existing direct drive wind turbine permanent magnet synchronous generator's magnetic field weakening control method is complex in principle and difficult to adjust the parameters, on the basis of fully combining the overall control strategy of the wind turbine, a simple structure and stable The Maximum Available Torque (Maximum Available Torque, MAT) Field Weakening Control Method of Permanent Magnet Direct Drive Wind Turbines with Good and No Parameter Tuning

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