A low-voltage ride-through control method for double-fed wind power generation system

Abstract

The present invention discloses a double-fed wind generation system low-voltage ride-through control method. A reactive current meeting a power grid guide rule requirement is injected into a PCC in afault period, a rotor reactive current command as shown in the description is calculated to ensure that the total reactive current IGq injected into the PCC and the total active current IGd meets a condition as shown in the description; an active current command as shown in the description and a reactive current command as shown in the description of a converter at a network side are calculated; on the premise of ensuring the output of reactive current meeting the power grid guide rule requirement, a rotor active current command as shown in the description is calculated; and the control current commands as shown in the description are transmitted to a rotor current loop controller, and the control current commands are transmitted to a current loop controller at the network side. The unstability problem of a double-fed wind generation system in the faults of the power grid special in a weak grid is effectively solved, and the stable operation capacity of the double-fed wind generation system and the voltage quality of the connected power grid are improved.

Description

technical field [0001] The invention relates to an improved low-voltage ride-through control method of a doubly-fed wind power generation system, in order to improve the stability of the doubly-fed wind power generation system under fault conditions, and solve the oscillation in the doubly-fed wind power generation system during the fault process, especially in the weak grid fault process and out-of-sync problems. Background technique [0002] With the increasingly severe energy and environmental problems, wind power technology has received extensive attention and rapid development. Due to the distribution of wind energy, large-scale wind farms are generally located in relatively remote areas and connected to the power grid through long transmission lines, resulting in weakening of the power grid and adversely affecting the stable operation of the power grid. Especially when the power grid fails, due to the interaction between the controller and the long transmission line, ...

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Problems solved by technology

[0005] Literature (1) analyzes the influence of various factors such as phase-locked loop and current loop control parameters on the stability of the DFIG wind power generation system under severe faults in the weak grid, and does not involve effective control to improve the stability of the DFIG system during faults Strategy

Literature (2) explored the transient characteristics and dynamic behavior of the doubly-fed wind power system under different fault types and proposed an improved control strategy, but the article mainly focused on how to reduce the transient overcurrent on the rotor side during the fault, and did not examine the fault The dynamic stability problem of the system during the duration

Severe faults in the weak grid will bring adverse dynamic effects to the DFIG control system. Under the interaction between the controller and the line impedance, this adverse dynamic may lead to the instability of the DFIG wind power generation system, and even disconnection from the grid

At the same time, the instability of the wind power system during the fault period will further affect the stability of the grid after the fault is cleared, which may cause the grid voltage to drop again after the fault is cleared, or even collapse.

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