CN-122026546-A - Control synchronization-based virtual inertia control method and system for wind turbine generator set below cut-in wind speed

CN122026546ACN 122026546 ACN122026546 ACN 122026546ACN-122026546-A

Abstract

The invention discloses a control synchronization-based virtual inertia control method and system for a wind turbine generator set below cut-in wind speed. The invention designs a control strategy capable of simulating the self-synchronization characteristic of a synchronous camera and realizing inertia support. The method comprises the steps of firstly measuring wind speed, rotor rotating speed and power grid frequency in real time, secondly calculating average wind speed, judging operation conditions of a wind turbine generator according to hysteresis switching logic, then switching the wind turbine generator to a control synchronous mode when the condition of entering low wind speed is judged, establishing a proportional synchronous relation between the rotor rotating speed and the power grid frequency through a converter, maintaining synchronous rotating speed operation, providing inertia support for the power grid, and finally smoothly switching back to a maximum power point tracking or constant rotating speed control mode when the wind speed is recovered to be higher than the cut-in wind speed. The invention can enable the wind turbine generator to still have inertia supporting capability under the condition of cutting-in wind speed and even no wind, and effectively improve the frequency stability of the power system.

Inventors

LIU KUNLONG
ZHOU JIANHUA
HUO YULI
HU YINGJIE
FANG XIONGFENG
YIN MINGHUI
LI QUN
WANG CHENGGEN
CHEN ZAIYU
LI QIANG
YANG FEI
ZOU XIAOMING
GU LING

Assignees

南京理工大学
国网江苏省电力有限公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The virtual inertia control method for the wind turbine generator set below the cut-in wind speed based on control synchronization is characterized by comprising the following steps of: Acquiring real-time operation parameters of the wind turbine generator, wherein the operation parameters at least comprise wind speed, rotor rotation speed and grid frequency; determining a statistical characteristic value reflecting a wind speed trend according to the real-time wind speed, and judging whether the wind turbine generator starts to enter or exit a control synchronous mode based on a preset switching logic; when the starting is judged to enter a control synchronous mode, generating a rotor rotating speed instruction dynamically associated with the power grid frequency, and executing closed-loop rotating speed control on the wind turbine generator to enable the wind turbine generator to provide inertia support under working conditions below cut-in wind speed or no-wind working conditions; And when the control synchronous mode is judged to be exited, the control synchronous mode is released, namely the closed-loop rotating speed control is released, and the wind turbine generator is switched to the normal operation control mode.
2. The method for controlling virtual inertia of the wind turbine generator set below the cut-in wind speed based on control synchronization according to claim 1, wherein the statistical characteristic value reflecting the wind speed trend is a moving average wind speed, and the calculation formula is as follows: In the formula, For the purpose of a moving average wind speed, For a statistical period of the average wind speed, Is the current time.
3. The method for controlling virtual inertia of a wind turbine generator set below a cut-in wind speed based on control synchronization according to claim 1, wherein the preset switching logic specifically comprises: Setting a start threshold for controlling a synchronization mode And exit threshold And (2) and ; When the statistical characteristic value is reduced and meets a starting threshold value condition, starting a control synchronization mode, wherein the starting threshold value condition is that the statistical characteristic value is smaller than or equal to a starting threshold value, the wind turbine generator system executes control synchronization-based rotation speed tracking, and simultaneously sets a control mode state variable S to 1 ; When the statistical characteristic value rises and meets an exit threshold value condition, exiting the control synchronous mode, switching the wind turbine generator to a normal operation control mode, and setting a control mode state variable S to 0, wherein the exit threshold value condition is that the statistical characteristic value is larger than the exit threshold value ; When the statistical characteristic value is at the starting threshold value And exit threshold And during the time, the current control mode of the wind turbine generator is kept unchanged.
4. The method for controlling virtual inertia of a wind turbine generator set below a cut-in wind speed based on control synchronization according to claim 3, wherein the rotor rotation speed command is determined based on a proportional synchronization relation, and a specific formula is as follows: In the formula, Is the rotation speed command value of the rotor, Is a synchronization coefficient; Rated frequency for the power grid; for corresponding to rated frequency of electric network Is characterized in that the fan rotor is synchronous in rotating speed, The power generation rotating speed is started for the fan, Is the grid frequency.
5. The method for controlling virtual inertia of wind turbine generator set below cut-in wind speed based on control synchronization of claim 4, further comprising dynamically switching and adjusting an upper limit value of active power output of a closed-loop rotational speed controller according to a state variable S of the control mode when the rotational speed closed-loop control is executed, wherein the specific formula is as follows: In the formula, For the upper clipping value of the active power output, The optimal power coefficient of the wind turbine generator is obtained; is the rated power of the wind turbine generator, Is the rotor speed.
6. The method for controlling virtual inertia of wind turbines below cut-in wind speed based on control synchronization according to claim 5, wherein the closed loop rotational speed control tracks rotor rotational speed instructions by using a proportional-integral controller with output limiting, i.e. a PI controller.
7. The method for controlling virtual inertia of wind turbines under cut-in wind speed based on control synchronization according to claim 6, wherein the active power reference command of the PI controller is calculated by the following formula and executed by a converter; In the formula, As a reference to the active power command, Is the proportionality coefficient of the PI controller; the integral coefficient of the PI controller; as a limiting function, the input quantity is represented Is limited to In the interval of the two-dimensional space, Are used only to indicate a variable, and have no actual meaning.
8. The method for controlling virtual inertia of a wind turbine generator below a cut-in wind speed based on control synchronization of claim 1, wherein the normal operation control mode comprises a maximum power tracking control or a constant rotation speed control mode.
9. A control synchronization based virtual inertia control system for a wind turbine below cut-in wind speed based on the method of any of claims 1 to 8, the system comprising: the first module is used for acquiring real-time operation parameters of the wind turbine generator, wherein the operation parameters at least comprise wind speed, rotor rotating speed and grid frequency; The second module is used for calculating a statistical characteristic value reflecting the wind speed trend and judging the start-stop state of the control synchronous mode based on a preset switching logic; and the third module is used for generating a rotor rotating speed instruction related to the power grid frequency in a control synchronous mode, and executing closed-loop rotating speed control through the converter to realize inertia support or execute control synchronous mode release operation.
10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 8 when executing the computer program.

Description

Control synchronization-based virtual inertia control method and system for wind turbine generator set below cut-in wind speed Technical Field The invention belongs to the technical field of wind power generation control, and particularly relates to a method and a system for controlling virtual inertia of a wind turbine generator set below cut-in wind speed based on control synchronization. Background With the advancement of global energy transformation, the permeability of new energy, represented by wind power, in an electric power system is continuously improved. Since wind turbines are usually connected to the grid via a power electronic converter, their rotational speed is decoupled from the grid frequency, so that they cannot respond directly to the grid frequency change, as in conventional synchronous generators. This causes the equivalent moment of inertia of the power system to drop significantly, and frequency fluctuation caused by load disturbance is more severe, so that the problem of system frequency stability is increasingly prominent. Therefore, the wind turbine generator system has inertia supporting capability similar to that of a synchronous generator, and becomes an urgent requirement of current power grid guidelines and a research hot spot of scientific research. To achieve this goal, the prior art generally employs virtual inertia control strategies. The strategy simulates the inertial power external characteristic of the synchronous generator by adding a power instruction which is proportional to the frequency change rate of the power grid on the maximum power point tracking curve and utilizing the flexible regulation characteristic of the active output force of the fan. However, this power regulation-based control has a significant limitation in that it relies on the wind turbine being in a normal generating state (i.e., wind speeds higher than cut-in wind speeds). When the wind speed is lower than the cut-in wind speed, the wind turbine generator is usually in a stop state or a low-rotation-speed standby state, and support cannot be provided by adjusting active power. Statistics show that in a low wind speed site or an inland complex terrain area, the time occupied by the wind turbine generator set under the cut-in wind speed is relatively high throughout the year, which means that in a quite long time, huge rotor inertia resources of the wind turbine generator set are in an idle waste state, and the required frequency support cannot be provided for a power grid. In contrast, the conventional synchronous camera has no prime motor drive, but can still maintain synchronous rotation with the frequency of the power grid by virtue of the self-synchronizing effect brought by the electromechanical structural design of the synchronous camera, and provides inertia support by releasing the kinetic energy of the rotor when the frequency is changed. The wind turbine generator set also has a physical rotor with large inertia, if the operation mechanism of the synchronous camera can be used for referencing, the dependence of the traditional control on pneumatic power is broken through, the self-synchronization characteristic is simulated by a control means below the cut-in wind speed, so that the wind turbine generator set can maintain synchronous rotation and respond to frequency change under weak wind even no wind conditions, the time for providing auxiliary service for the wind turbine generator set can be greatly prolonged, the inertia supporting potential of the wind turbine generator set is fully excavated, and the wind turbine generator set has important significance for improving the full-time frequency stability of a high-proportion new energy power system. Disclosure of Invention The invention aims to solve the problems in the prior art and provides a method and a system for controlling virtual inertia of a wind turbine generator set below cut-in wind speed based on control synchronization. According to the invention, a control synchronization mechanism is introduced in the converter control, so that the rotor speed of the wind turbine generator is dynamically bound with the frequency of the power grid, and the operation characteristic of the synchronous regulator is simulated under the low-wind-speed or even windless working condition, so that the inertia support of the power grid is realized. The technical scheme for achieving the purpose of the invention is that on one hand, a virtual inertia control method of a wind turbine generator set below cut-in wind speed based on control synchronization is provided, and the method comprises the following steps: Acquiring real-time operation parameters of the wind turbine generator, wherein the operation parameters at least comprise wind speed, rotor rotation speed and grid frequency; determining a statistical characteristic value reflecting a wind speed trend according to the real-time wind speed, and judging whether the wind turbine generator