Direct-drive fan high-penetration improved control based on virtual synchronization technology

A virtual synchronization and technical technology, applied in the direction of single-grid parallel feeding arrangement, reducing/preventing power oscillation, AC network voltage adjustment, etc. network hazards and other problems, to achieve the effect of stabilizing power output and slowing down the transition process

CN114362194APending Publication Date: 2022-04-15NORTH CHINA ELECTRIC POWER UNIV (BAODING) +1
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2022-04-15

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Abstract

The invention provides an improved control scheme for increasing the controllability of the GSC by dynamically adjusting the voltage of a DC bus during high voltage penetration, aiming at solving the problems that the transient overvoltage of a power grid easily causes that the grid-side converter of a direct-driven fan reaches the upper limit of the AC voltage regulation, so that the AC / DC power coupling oscillation is caused, and the instability or overvoltage generator tripping protection is caused. According to active control, the VSG technology is improved, a power compensation item is designed, system frequency support is added externally, and bus voltage fluctuation is reduced internally; reactive control is based on industrial standards, and voltage recovery is supported by injecting reactive current into a power grid. The improved control effectively improves the fault continuous ride-through capability of the unit, improves the power generation efficiency and the electric energy quality of the fan, and improves the system stability.
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Description

technical field

[0001] The invention relates to the field of inverter control for distributed power generation micro-grids, in particular to an improved high-throughput control of direct-drive wind turbines based on virtual synchronization technology. Background technique

[0002] The effective consumption of large-scale wind power often requires a high-voltage external transmission system. However, in a typical large-capacity new energy delivery project, the sending end system has a certain electrical distance from the main grid, and the capacity of the nearby supporting thermal power units is insufficient, making it a "weak support" grid characteristic.

[0003] A power grid with such characteristics, when various faults occur, is likely to cause large fluctuations in frequency and voltage, and trigger wind turbines to go off-grid, and even cause chain reactions in serious cases, causing blackouts. The design of the fan fault ride-through strategy helps to enhance the uni...

Examples

Embodiment Construction

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

[0033] The principle of VSG is to make the converter simulate the characteristics of inertia, damping and primary frequency modulation of traditional synchronous units by adding "swing equation" and "droop control" to the control of power electronic devices. The control part mainly includes: active power and frequency control loop, reactive power and voltage control loop, virtual impedance control, current closed-loop control, PWM modulation. The active power and frequency control loop consists of two parts: the inertia damping model and the frequency regulator model. Its differential equation is:

[0034]

[0035] P ref is the active power reference value, P e is the electromagnetic power output by VSG, ω s is the system reference angular velocity, J is the moment of i...