Faulty operation method of doubly-fed wind turbine under direct power control

Abstract

The invention discloses a fault operation method under direct power control of a doubly-fed wind power generator. The control method avoids complex coordinate transformation and compensation adjustment in vector control, and the control command is simple and direct, and is easy to implement. , the rotor flux linkage flux weakening predictive control is adopted, the given value of the rotor flux linkage is calculated by the actual value of the stator flux linkage, and the discrete model of the converter voltage on the rotor side of the doubly-fed wind turbine is used to predict the different switching states of the converter at the next moment The dynamic behavior of the seven voltage vectors is evaluated by the value function, and finally the voltage vector that minimizes the value function is selected. This algorithm can predict the optimal switching state in each sampling period as the switching signal of the converter. The invention does not need synchronous rotating coordinate system conversion and PI regulator design, has fast dynamic response, simple control instructions, and is easy to implement, and improves the fault operation capability of the double-fed wind power generator during the fault process.

Description

technical field [0001] The invention belongs to the technical field of control of a doubly-fed wind power generator rotor side converter, and is respectively aimed at a direct power control method when the grid voltage is in a steady state and a rotor flux-linkage flux-weakening predictive control method when the grid voltage suddenly drops. Background technique [0002] Wind energy is a random, explosive, and uncertain energy source. The random fluctuation of electric energy generated by the wind power generation system has a great impact on the power grid. How to maintain the voltage of the power grid when the wind power generation system and power loads are in a fluctuating state The amplitude and frequency are within the allowable range, and how to ensure the stability of the grid operation during the dynamic adjustment process of the wind turbine is the requirement of the wind power generation system for the grid. These problems must be seriously faced and resolved, oth...

AI Technical Summary

Problems solved by technology

This method increases the cost of hardware, and absorbs a large amount of reactive power from the grid when a fault occurs, which affects the stability of the grid, and the transient electromagnetic impact on the grid and the mechanical impact of the wind turbine are very serious.

When the grid voltage has a single-phase 90% or three-phase symmetrical drop of 70% or more serious faults, the rotor current of the doubly-fed wind turbine can hardly be controlled within 2 times the rated current, which will cause serious damage to the unit.

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