Current non-delay control method of AC excitation double-fed asynchronous wind power generator rotor

Abstract

The invention discloses a method for controlling rotor current of an AC excitation asynchronous doubly-fed induction generator (DFIG) without time delay. The method comprises acquiring a three-phase rotor current signal to perform rotational coordinate conversion to obtain rotor current feedback quantity in a positive rotation synchronous rotating coordinate system, compared with the rotor current command in the same coordinate system, inputting the error signal to a proportion-integral regulator for regulation, performing feedback compensation and decoupling to obtain rotor reference voltage in the positive rotation synchronous rotating coordinate system, converting to the rotor reference voltage for space vector pulse width modulation in a rotor coordinate system, and generating a switching signal for power devices of a rotor side transformer to control on-line operation of DFIG . The inventive method does not require performing positive and negative sequence decomposition of rotor current neither under balanced network voltage nor under imbalanced network voltage, and does not cause decomposition delay, so as to realize enhanced control target of the power generation system under imbalanced network voltage and effectively improve the uninterrupted operation (passing through) ability of the power generation system under network failure.

Description

technical field [0001] The invention relates to a control method for the rotor current of a wind power generator, especially an AC excitation doubly-fed asynchronous wind power generator (DFIG) suitable for grid voltage balance and unbalance (including small-value steady state and large-value transient unbalance) conditions. ) rotor current without delay control method. Background technique [0002] Modern large-scale wind power generation systems mainly include double-fed asynchronous generators (DFIG) and permanent magnet synchronous generators. In order to improve power generation efficiency, variable-speed constant-frequency power generation operations are implemented, and the DFIG system is the current mainstream model. At present, my country's wind power technology mostly stays in the operation control under ideal grid conditions. Since the actual grid often has various symmetrical and asymmetrical faults, it is necessary to carry out research on operation control unde...

AI Technical Summary

Problems solved by technology

In addition to the delay introduced during the separation, the bandwidth of the control system will be affected, which will cause dynamic tracking errors and the dynamic control effect is not ideal

What's more, the circuit cannot distinguish whether the grid voltage is balanced or unbalanced, and whether positive and negative sequence system decomposition is required

If DFIG operates in a state of strict grid voltage balance, the control system will still use a notch filter to separate the rotor variable, which will bring unnecessary delay to the normal control of the system and seriously affect the dynamic control performance of the system

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