A control method and device for a three-phase PWM rectifier

Abstract

The present application provides a method and a device for controlling a three-phase PWM rectifier, and relates to the technical field of power. The method comprises the steps of: converting an outputthree-phase voltage of a wind power generator to an [alpha]-axis voltage component ug[alpha] and a [beta]-axis voltage component ug[beta] in an [alpha]-[beta] two-phase stationary coordinate system and an [alpha]*axis voltage component u*g[alpha] and a [beta]*axis voltage component u*g[beta] in an [alpha]*-[beta]* two-phase stationary coordinate system; determining a regulation factor kcm; according to the kcm and a u*g[alpha], determining a first voltage component, and according to the kcm and a u*g[beta], determining a second voltage component; taking the sum of ug[alpha] and the first voltage component as a first controlled quantity, and taking the sum of the ug[beta] and the second voltage component as a second controlled quantity; and according to the first controlled quantity and the second controlled quantity, generating the pulse signals used for on-off of the power switching device of each bridge arm of the three-phase PWM rectifier. By adopting the invention, the response speed can be improved when the three-phase PWM rectifier is controlled.

Description

technical field [0001] The present application relates to the field of electric power technology, in particular to a control method and device for a three-phase PWM rectifier. Background technique [0002] At present, the three-phase PWM (Pulse width modulation, pulse width modulation) rectifier has been widely used in wind power generation and other fields due to its advantages of sinusoidal AC side current and unit power factor operation. [0003] The control strategy of the existing three-phase PWM rectifier is usually a control strategy with a phase-locked link and a control strategy without a phase-locked link, while the control strategy with a phase-locked link is usually established on a two-phase synchronous rotating coordinate system, relying on the lock The phase loop realizes the synchronization with the AC side voltage vector. The detection accuracy of the phase-locked loop is a key factor affecting the control performance of wind turbines, but when the AC side ...

AI Technical Summary

Problems solved by technology

The detection accuracy of the phase-locked loop is a key factor affecting the control performance of wind turbines, but when the AC side voltage of the three-phase PWM rectifier is distorted or the frequency changes suddenly, the phase-locked loop will not be able to quickly and accurately detect the voltage synchronization signal, reducing the Operational performance of wind turbines

In addition, the phase-locked loop also increases the complexity of the control system, making the response speed lower when controlling the three-phase PWM rectifier

In addition, in the control strategy with a phase-locked link, the model of the three-phase PWM rectifier in the two-phase rotating coordinate system contains cross-coupling items, which requires feed-forward decoupling control, which further increases the complexity of the control algorithm structure, making it difficult to control the three-phase PWM rectifier. Slow response speed when phase PWM rectifier

[0004] The control strategy without a phase-locked link is usually established on the virtual dq coordinate system with a fixed rotation frequency, that is, after Park (Parker) transformation, the decoupling control of the dq axis components is performed in the dq coordinate system, which also increases the control algorithm complexity, making the response speed slow when controlling the three-phase PWM rectifier

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