Method for controlling direct-current bus voltage of double-fed wind power converter

Abstract

The invention relates to a method for controlling the direct-current bus voltage of a double-fed wind power converter. The method employs a network side converter and a machine side converter to commonly control a direct-current bus voltage, the network side converter has a main effect, and the machine side converter performs auxiliary control for the transient process. In a network side convertercontrol unit, according to the voltage effective value and the generator slip of the power grid, a direct-current bus voltage reference value is calculated; an energy current feed-forward value and adirect current bus voltage closed-loop output current reference value are generated according to the direct-current bus voltage deviation, and the energy current feed-forward value and the direct current bus voltage closed-loop output current reference value are added as the network side active current reference value. In a machine side converter control unit, a steady-state self-attenuation PI regulator with hysteresis is adopted to perform auxiliary control on direct-current bus voltage in a transient process, and a control result and an active power instruction of a main controller of a wind turbine generator set are added to form a machine side active current reference value. The method can improve the stability of the voltage control of the direct current bus, and is beneficial to the excavation of the supporting capability of the doubly-fed wind motor group on the frequency and the voltage in the transient process of the power grid.

Description

technical field [0001] The invention relates to a method for controlling the DC bus voltage of a doubly-fed wind power converter. Background technique [0002] In recent years, the utilization of renewable energy, especially wind energy, has been paid more and more attention. Among many wind power generation schemes, variable speed constant frequency doubly-fed wind turbines are widely used in power levels of 2MW and below due to the advantages of small converter capacity, high system efficiency, and controllable power factor. In the double-fed power generation system, the stator of the generator is connected to the grid, and the rotor is excited by the three-phase slip frequency current provided by the double-fed converter. In the variable speed operation of tracking the maximum wind energy, the amplitude, frequency and phase of the rotor excitation current are adjusted at any time, so that the generator can operate at variable speed and constant frequency in a wide range ...

AI Technical Summary

Problems solved by technology

Both solutions require the addition of additional components, resulting in an increase in the cost of the doubly-fed converter

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