CN-122001030-A - Network side control method and system of converter system, converter system and doubly-fed wind power generation system

CN122001030ACN 122001030 ACN122001030 ACN 122001030ACN-122001030-A

Abstract

The invention relates to a grid-side control method and system of a converter system, the converter system and a doubly-fed wind power generation system, and belongs to the technical field of grid-connected control. According to the method, when a high-voltage fault of a machine end occurs in a doubly-fed wind power generation system where a converter system is located, a network side active current reference value when the voltage of the machine end is abnormally increased is obtained through consistency of two active power changes of a network side and a rotor side, network side reactive current is obtained through derivation of a direct-current bus voltage limiting condition, the maximum value of the network side reactive current is used as the network side reactive current reference value when the voltage of the machine end is abnormally increased, network side active current loop adjustment control is conducted on a difference value between the network side active current reference value and a network side active current actual value, network side reactive current loop adjustment control is conducted on a difference value between the network side reactive current reference value and the network side reactive current actual value, and a control signal is generated according to a result of the two current loop adjustment control, so that the situation that the converter system cannot operate is avoided.

Inventors

QI ZHENGHAO
LI DALEI
WANG GUOJUN
CHANG WEI
CHENG WEIDONG
LEI ZHENFENG
WANG JINGDAN
YUAN JINKU
LIU SHUCAI
Chang Lefeng
WANG YANFENG
ZHAO WANGYANG

Assignees

许继电气股份有限公司郑州电力设计院分公司

Dates

Publication Date: 20260508
Application Date: 20241210
Priority Date: 20241108

Claims (10)

1. A network side control method of a converter system, comprising the steps of: Performing network side active current loop regulation control on a difference value between a network side active current reference value and a network side active current actual value, performing network side reactive current loop regulation control on a difference value between a network side reactive current reference value and a network side reactive current actual value, and generating a control signal for controlling a network side converter in a converter system according to a network side active current loop regulation control result and a network side reactive current loop regulation control result; When a doubly-fed wind power generation system with a converter system is in a high-voltage fault at a machine end, the network side active current reference value is obtained according to the network side active power reference value, the network side active power reference value adopts rotor side active power, the network side reactive current reference value takes the maximum value of network side reactive current, the network side reactive current is deduced according to a direct current bus voltage limiting condition, and the expression of the direct current bus voltage limiting condition is as follows: Wherein U dc is direct current bus voltage, omega 1 is synchronous rotation speed, L g is incoming line reactor inductance, i gq is network side reactive current, and U g is power grid voltage.
2. The grid-side control method of a converter system according to claim 1, wherein the expression of the grid-side reactive current reference value is: in the formula, For a network side reactive current reference value, U dc is direct current bus voltage, U g is power grid voltage, omega 1 is synchronous rotation speed, L g is an incoming line reactor inductance, k is a transient coefficient, and t is time; Or the expression of the network side reactive current reference value is as follows: in the formula, For the network side reactive current reference value, U dc is the direct current bus voltage, U g is the grid voltage, ω 1 is the synchronous rotation speed, L g is the incoming line reactor inductance, and k is the transient coefficient.
3. The grid-side control method of a current transformer system according to claim 1, wherein the grid-side active current loop regulation control is implemented by a first-order active disturbance rejection controller, and the total disturbance of the system of the first-order active disturbance rejection controller is a current change caused by a grid voltage change.
4. The grid-side control method of a converter system according to claim 1, wherein the grid-side reactive current loop regulation control is implemented by a first-order active disturbance rejection controller, and a total disturbance of the system of the first-order active disturbance rejection controller is a current change caused by a grid voltage change.
5. The grid-side control method of a converter system according to any one of claims 1 to 4, wherein the grid-side active current reference value is an output of a voltage outer loop controller, and an input of the voltage outer loop controller is a difference between a dc bus voltage reference value and a dc bus voltage actual value, when the doubly-fed wind power generation system is operating normally.
6. A grid-side control method of a converter system according to any of claims 1-4, characterized in that the grid-side reactive current reference value is 0 when the doubly-fed wind power system is operating normally.
7. The grid-side control method of a converter system according to any one of claims 1 to 4, wherein the expression of the grid-side active current reference value is: in the formula, As the net side active current reference value, As the active power reference value at the network side, u g is the network voltage.
8. A grid-side control system of a converter system, comprising a processor, characterized in that the processor is adapted to execute a computer program for implementing the steps of the grid-side control method of a converter system according to any of claims 1 to 7.
9. A converter system comprising a grid-side converter and a controller of the grid-side converter, the controller of the grid-side converter controlling a connection to the grid-side converter, the controller comprising a processor, characterized in that the processor is adapted to execute a computer program for carrying out the steps of the grid-side control method of the converter system according to any one of claims 1 to 7.
10. A doubly-fed wind power generation system comprising a grid-side converter and a controller of the grid-side converter, the controller of the grid-side converter controlling a connection to the grid-side converter, the controller comprising a processor, characterized in that the processor is adapted to execute a computer program for carrying out the steps of the grid-side control method of the converter system according to any one of claims 1 to 7.

Description

Network side control method and system of converter system, converter system and doubly-fed wind power generation system Technical Field The invention relates to a grid-side control method and system of a converter system, the converter system and a doubly-fed wind power generation system, and belongs to the technical field of grid-connected control. Background A doubly-fed wind power generation system is used in a large amount as a main stream system of wind power generation. In a doubly-fed wind power generation system, the stator side of a doubly-fed generator is directly connected to a power grid, and the rotor side of the doubly-fed generator is connected to the power grid through a back-to-back converter system. The rotor and stator of the generator are both capable of feeding electrical energy into the grid, and are therefore known as "doubly fed" generators. This back-to-back converter system is typically composed of a rotor-side converter (Rotor Side Converter, RSC) and a grid-side converter (Grid Side Converter, GSC), with energy buffering and controlled decoupling between the rotor-side and grid-side converters by means of dc bus direct-current capacitors, which allows the doubly-fed generator to flexibly control its power delivered to the grid. The safe and stable operation of the power grid brings more stringent requirements on the power generation technology and the fault ride-through capability of the doubly-fed wind power generation system, wherein the fault ride-through capability refers to the capability of ensuring that a wind turbine generator can continuously operate without off-grid according to standard requirements and stably transition to a normal operation state within a certain voltage or frequency range and a duration interval when grid-connected point voltage or frequency is beyond a standard allowable normal operation range caused by power system accidents or disturbance. Unlike the scenario where the system short-circuit fault causes the low voltage ride through problem, the wind power high voltage ride through problem at present mainly occurs in the large-scale wind power base DC output scenario. When the direct current inversion station fails to commutate or is blocked, the filter capacitor and the reactive power compensation device generate excessive reactive power to cause transient overvoltage of the alternating current bus at the transmitting end, so that the fan has high-voltage off-grid risk. The existing high-voltage ride through control method for the doubly-fed wind power generation system mainly comprises the steps of adding hardware circuit protection measures and improving control strategies, and the main purpose of the method is to ensure that the doubly-fed wind power generation system can stably operate when the voltage of a power grid is abnormally increased and reduce impact on the power grid. However, most of researches are focused on a rotor-side converter, for example, a patent document with publication number CN114665515A discloses a high-voltage ride-through control method for introducing active disturbance rejection control, the method introduces the active disturbance rejection control into a rotor-side current inner loop, and simulation results show that the proposed high-voltage ride-through control method can effectively reduce rotor-side current and reduce fluctuation time. The influence of current transient of the grid-side converter, which is caused by abnormal rise of voltage at the end when the doubly-fed wind power generation system breaks down at high voltage, on the voltage and reactive power of the direct-current bus is usually ignored, and the capacitor at the direct-current bus is damaged due to the fact that the voltage of the direct-current bus rises, so that the doubly-fed wind power generation system cannot operate finally. Disclosure of Invention The invention aims to provide a grid-side control method, a control system and a current transformer system of the current transformer system, which are used for solving the problem that the current transformer system cannot operate due to the fact that the current transient of a grid-side current transformer is ignored in high-voltage ride through control when the existing current transformer system is in high-voltage fault, and the problem that the doubly-fed wind power generation system cannot operate due to the fact that the current transient of the grid-side current transformer is ignored in high-voltage ride through control when the existing doubly-fed wind power generation system is in high-voltage fault. In order to achieve the above object, the present invention provides a method comprising: The invention relates to a network side control method of a converter system, which comprises the following steps: Performing network side active current loop regulation control on a difference value between a network side active current reference value and a network side active current actual