CN111641229B - Wind power generation system output monitoring method and system based on extended harmonic domain model - Google Patents

Wind power generation system output monitoring method and system based on extended harmonic domain model Download PDF

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CN111641229B
CN111641229B CN202010548069.3A CN202010548069A CN111641229B CN 111641229 B CN111641229 B CN 111641229B CN 202010548069 A CN202010548069 A CN 202010548069A CN 111641229 B CN111641229 B CN 111641229B
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CN111641229A (en
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孙媛媛
许庆燊
李亚辉
王庆岩
路彤
庄静茹
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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Abstract

本公开提出了基于扩展谐波域模型的风力发电系统输出监测方法及系统，其中，动态模型包括：分别针对风力发电机、背靠背变换器的网侧系统和直流母线建立基于扩展谐波域的双馈异步发电机动态模型、基于扩展谐波域的变换器网侧系统动态模型和基于扩展谐波域的变换器直流母线动态模型。同时还将变换器两侧的开关函数产生的谐波含量考虑在网侧系统和直流母线的扩展谐波域模型中。将发电机、背靠背变换器的网侧系统和直流母线共三个子模型合并为一个谐波状态空间方程，得到双馈风力发电系统的扩展谐波域模型，实现了对发电机定转子电流的动态跟踪，不仅能精准表征基频电流的变化，亦可用于分析高倍频定子谐波电流特征，达到监测和准确评估的目的。

Figure 202010548069

The present disclosure proposes an output monitoring method and system for a wind power generation system based on an extended harmonic domain model, wherein the dynamic model includes: establishing an extended harmonic domain-based dual system for the wind turbine, the grid-side system of the back-to-back converter, and the DC bus, respectively. The dynamic model of the fed asynchronous generator, the dynamic model of the grid-side system of the converter based on the extended harmonic domain, and the dynamic model of the DC bus of the converter based on the extended harmonic domain. At the same time, the harmonic content generated by the switching functions on both sides of the converter is also considered in the extended harmonic domain model of the grid-side system and the DC bus. The three sub-models of the generator, the grid-side system of the back-to-back converter and the DC bus are combined into a harmonic state space equation, and the extended harmonic domain model of the doubly-fed wind power generation system is obtained. Tracking can not only accurately characterize the change of the fundamental frequency current, but also can be used to analyze the characteristics of the harmonic current of the high frequency multiplier stator to achieve the purpose of monitoring and accurate evaluation.

Figure 202010548069

Description

基于扩展谐波域模型的风力发电系统输出监测方法及系统Wind power generation system output monitoring method and system based on extended harmonic domain model

技术领域technical field

本公开涉及风力发电相关技术领域，具体的说，是涉及基于扩展谐波域模型的风力发电系统输出监测方法及系统。The present disclosure relates to the technical field of wind power generation, in particular, to a method and system for monitoring the output of a wind power generation system based on an extended harmonic domain model.

背景技术Background technique

本部分的陈述仅仅是提供了与本公开相关的背景技术信息，并不必然构成在先技术。The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

为缓解能源危机，减轻环境污染，可再生能源发电迅速崛起。风电作为中国第三大电源，双馈异步风力发电机(Doubly-Fed Induction Generator，DFIG)是并网风机中的主流机型。风速变化具有的随机性、间歇性特点导致电能输出不稳定，因此风力发电并网时需接入大量电力电子装置以控制输出电能符合并网标准。而电力电子装置的应用同时引入了高频次、宽频域的不确定性谐波电流，当发电机定子电压和电流中含有谐波分量时，会使定子输出有功功率和无功功率发生脉动，易诱发风机与电网的振荡、瞬时谐波相互作用和电压闪变等复杂问题，严重时导致风机解列，影响电网安全稳定运行。双馈风力发电系统内部谐波的影响因素众多，包括电网背景谐波、电力电子器件调制等，要准确把握双馈风机的谐波输出特征，首先要建立精确的风机动态模型，分析其内部的暂态变化过程，获知电机谐波电流的连续时间域的变化情况以及可能的暂态不安全行为，为进一步研究风机与电网间的谐波相互作用提供理论基础，并为后续设计滤波器和改善控制策略提供模型基础。In order to alleviate the energy crisis and reduce environmental pollution, renewable energy power generation has risen rapidly. Wind power is the third largest power source in China. Doubly-Fed Induction Generator (DFIG) is the mainstream type of grid-connected wind turbine. The random and intermittent characteristics of wind speed change lead to unstable power output. Therefore, when wind power generation is connected to the grid, a large number of power electronic devices need to be connected to control the output power to meet the grid-connected standards. The application of power electronic devices also introduces uncertain harmonic currents of high frequency and wide frequency domain. When the generator stator voltage and current contain harmonic components, the stator output active power and reactive power will pulsate. It is easy to induce complex problems such as oscillation between the wind turbine and the power grid, instantaneous harmonic interaction and voltage flicker. There are many factors affecting the internal harmonics of the DFIG wind power generation system, including the background harmonics of the power grid and the modulation of power electronic devices. During the transient change process, the continuous time domain changes of the harmonic current of the motor and the possible transient unsafe behavior can be known, which provides a theoretical basis for further research on the harmonic interaction between the wind turbine and the power grid, and provides a theoretical basis for the subsequent design of filters and improvements. Control strategies provide the basis for the model.

国内外学者在建立双馈风力发电系统的动态模型方面已有一定研究，分析风机并网点谐波特性主要运用时域仿真方法，量化不同出力和风况下的谐波变化，并给出风机并网点的谐波频谱。对于双馈风力发电机，发电机模型的选择影响定子电流计算的精度。然而双馈风力发电系统复杂的系统构造和控制策略制约了模型精度，大部分动态模型对风机进行了不同程度的简化，常基于简化的背靠背变换器建立风机的平均值模型。发明人发现，简化背靠背变换器，忽略开关调制过程，会导致模型分析谐波的准确度降低，同时对风机运行的暂态过程及其控制的把握也会有偏差。同时，现有平均模型一般应用于连续时不变系统，不满足跟踪系统内各变量的动态变化的要求。另一方面，现有的风机通用平均模型通过dq坐标变换，使基频成分在dq坐标系下转换为直流量，但是单一的dq变换无法顾及到其他稳态谐波，应用于分析谐波特性计算量较大。Scholars at home and abroad have done some research on establishing the dynamic model of the doubly-fed wind power generation system. To analyze the harmonic characteristics of the wind turbine grid connection point, the time domain simulation method is mainly used to quantify the harmonic changes under different output and wind conditions, and give the grid connection point of the wind turbine. the harmonic spectrum. For doubly-fed wind turbines, the choice of generator model affects the accuracy of the stator current calculation. However, the complex system structure and control strategy of the doubly-fed wind power generation system restrict the model accuracy. Most of the dynamic models simplify the wind turbine to varying degrees, and the average value model of the wind turbine is often established based on the simplified back-to-back converter. The inventors found that simplifying the back-to-back converter and ignoring the switching modulation process will lead to a decrease in the accuracy of model analysis of harmonics, and at the same time, there will be deviations in the grasp of the transient process of fan operation and its control. At the same time, the existing average models are generally applied to continuous time-invariant systems, which do not meet the requirements of tracking the dynamic changes of variables in the system. On the other hand, the existing general average model of the fan converts the fundamental frequency component into a DC quantity in the dq coordinate system through the dq coordinate transformation, but the single dq transformation cannot take into account other steady-state harmonics, so it is used to analyze the harmonic characteristics The amount of calculation is large.

发明内容SUMMARY OF THE INVENTION

本公开为了解决上述问题，提出了基于扩展谐波域模型的风力发电系统输出监测方法及系统，扩展谐波域模型考虑了双馈异步发电机定子电压、定子电流、转子电压和转子电流的各次谐波的状态空间模型，既适用于表征暂态情况下的谐波动态，又可用于分析稳态情况下发电机定子输出电流的谐波特征，达到监测和准确评估的目的。In order to solve the above problems, the present disclosure proposes an output monitoring method and system for a wind power generation system based on an extended harmonic domain model. The state space model of sub-harmonic is not only suitable for characterizing the harmonic dynamics under transient conditions, but also for analyzing the harmonic characteristics of generator stator output current under steady-state conditions, so as to achieve the purpose of monitoring and accurate evaluation.

为了实现上述目的，本公开采用如下技术方案：In order to achieve the above object, the present disclosure adopts the following technical solutions:

一个或多个实施例提供了基于扩展谐波域模型的风力发电系统输出监测方法，包括如下步骤：One or more embodiments provide a wind power generation system output monitoring method based on an extended harmonic domain model, including the following steps:

分别针对风力发电机、变换器的网侧系统和直流母线建立时域模型；Establish time domain models for wind turbines, grid-side systems of converters and DC bus respectively;

分别获取风力发电机、变换器的网侧系统和直流母线的电气参数数据；Obtain the electrical parameter data of the wind turbine, the grid-side system of the converter and the DC bus respectively;

针对建立的时域模型，通过矢量变换以及频域定常化，根据获取的电气参数数据分别针对风力发电机、变换器的网侧系统和直流母线建立扩展谐波域模型；According to the established time domain model, through vector transformation and frequency domain normalization, according to the obtained electrical parameter data, an extended harmonic domain model is established for the wind turbine, the grid-side system of the converter and the DC bus respectively;

整合建立的扩展谐波域模型，以电机定子端电压为输入，输出为电机定子电流、转子电流、网侧电流和变换器中直流母线电压的各次谐波分量，得到双馈异步风力发电机的整体扩展谐波域动态模型，利用所述模型对风力发电系统的输出状态进行监测。Integrate the established extended harmonic domain model, take the motor stator terminal voltage as the input, and output the motor stator current, rotor current, grid-side current and the harmonic components of the DC bus voltage in the converter, and obtain the double-fed asynchronous wind generator. The overall extended harmonic domain dynamic model is used to monitor the output state of the wind power generation system.

一个或多个实施例提供了基于扩展谐波域模型的风力发电系统输出监测系统，包括：One or more embodiments provide a wind power generation system output monitoring system based on an extended harmonic domain model, including:

时域模型建立模块：被配置用于分别针对风力发电机、变换器的网侧系统和直流母线建立时域模型；Time-domain model building module: configured to build time-domain models for wind turbines, grid-side systems of converters, and DC bus, respectively;

数据获取模块：被配置用于分别获取风力发电机、变换器的网侧系统和直流母线的电气参数数据；Data acquisition module: configured to acquire the electrical parameter data of the wind turbine, the grid-side system of the converter and the DC bus, respectively;

扩展谐波域模型建立模块：被配置用于针对建立的时域模型，通过矢量变换以及频域定常化，根据获取的电气参数数据分别针对风力发电机、变换器的网侧系统和直流母线建立扩展谐波域模型；Extended harmonic domain model building module: configured for the established time domain model, through vector transformation and frequency domain normalization, according to the acquired electrical parameter data for wind turbines, converter grid-side systems and DC bus. Extended harmonic domain model;

整合监测模块：被配置用于整合建立的扩展谐波域模型，以电机定子端电压为输入，输出为电机定子电流、转子电流、网侧电流和变换器中直流母线电压的各次谐波分量，得到双馈异步风力发电机的整体扩展谐波域动态模型，利用所述模型对风力发电系统的输出状态进行监测。Integrated monitoring module: It is configured to integrate the established extended harmonic domain model, taking the motor stator terminal voltage as the input, and the output is the motor stator current, rotor current, grid-side current and the DC bus voltage in the converter. The harmonic components of each order , obtain the overall extended harmonic domain dynamic model of the doubly-fed asynchronous wind turbine, and use the model to monitor the output state of the wind power generation system.

一种电子设备，包括存储器和处理器以及存储在存储器上并在处理器上运行的计算机指令，所述计算机指令被处理器运行时，完成权利要求上述方法所述的步骤。An electronic device comprising a memory and a processor and computer instructions stored on the memory and executed on the processor, the computer instructions, when executed by the processor, perform the steps described in the above method of the claim.

一种计算机可读存储介质，用于存储计算机指令，所述计算机指令被处理器执行时，完成上述方法所述的步骤。A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps described in the above method are completed.

与现有技术相比，本公开的有益效果为：Compared with the prior art, the beneficial effects of the present disclosure are:

本公开建立了双馈风力发电系统“频域定常化”后的扩展谐波域模型，既适用于表征暂态情况下的谐波动态，又可用于分析稳态情况下整个发电系统内部变量的谐波特征，达到监测和准确评估的目的。The present disclosure establishes an extended harmonic domain model after the "frequency domain normalization" of a doubly-fed wind power generation system, which is not only suitable for characterizing the harmonic dynamics under transient conditions, but also for analyzing the internal variables of the entire power generation system under steady-state conditions. Harmonic characteristics, to achieve the purpose of monitoring and accurate evaluation.

本公开提出的方法打破现有风机通用平均模型通过dq坐标变换计算单一稳态谐波的局限，提出的扩展谐波域模型在状态空间内包含了状态变量、输入量和输出量的多个频率分量，能同时表示各变量的基频和倍数频率响应，分析的谐波次数还可任意选择，将其作为双馈风力发电系统的建模框架能大大降低谐波计算工作量。The method proposed by the present disclosure breaks the limitation of calculating a single steady-state harmonic through the dq coordinate transformation of the existing general average model of wind turbines, and the proposed extended harmonic domain model includes multiple frequencies of state variables, input quantities and output quantities in the state space. It can represent the fundamental frequency and multiple frequency response of each variable at the same time, and the harmonic order of the analysis can be arbitrarily selected. Using it as the modeling framework of the doubly-fed wind power generation system can greatly reduce the workload of harmonic calculation.

附图说明Description of drawings

构成本公开的一部分的说明书附图用来提供对本公开的进一步理解，本公开的示意性实施例及其说明用于解释本公开，并不构成对本公开的限定。The accompanying drawings, which constitute a part of the present disclosure, are used to provide further understanding of the present disclosure, and the exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure, but not to limit the present disclosure.

图1为本公开实施例1的方法流程图；1 is a flow chart of the method of Embodiment 1 of the present disclosure;

图2为本公开实施例1提供的同步旋转坐标系中双馈异步发电机的dq等效电路模型图；2 is a dq equivalent circuit model diagram of a doubly-fed asynchronous generator in a synchronous rotating coordinate system provided in Embodiment 1 of the present disclosure;

图3为本公开实施例1提供的背靠背变换器的网侧系统和直流母线的简化模型图；3 is a simplified model diagram of a grid-side system and a DC bus of a back-to-back converter provided in Embodiment 1 of the present disclosure;

图4为本公开实施例1提供的风速恒定下谐波稳态分析结果(EHD模型)与电磁暂态模型(EMT模型)仿真结果的发电机定子电流频谱对比图；FIG. 4 is a generator stator current spectrum comparison diagram of the simulation result of the harmonic steady state analysis result (EHD model) and the electromagnetic transient model (EMT model) under constant wind speed provided in Embodiment 1 of the present disclosure;

图5为本公开实施例1的双馈异步风力发电机的整体扩展谐波域动态模型与电磁暂态模型、平均模型在变化风速下直流母线电压变化的对比图；5 is a comparison diagram of the overall extended harmonic domain dynamic model, the electromagnetic transient model, and the average model of the doubly-fed asynchronous wind turbine according to Embodiment 1 of the disclosure under the change of the DC bus voltage under changing wind speeds;

图6为本公开实施例1的双馈异步风力发电机的整体扩展谐波域动态模型与电磁暂态模型、平均模型在变化风速下定子基频电流的对比图；6 is a comparison diagram of an overall extended harmonic domain dynamic model, an electromagnetic transient model, and an average model of the doubly-fed asynchronous wind turbine according to Embodiment 1 of the present disclosure under varying wind speeds;

图7为本公开实施例1的双馈异步风力发电机的整体扩展谐波域动态模型与电磁暂态模型在变化风速下某个时间点对应的发电机定子谐波电流频谱对比图；7 is a comparison diagram of the generator stator harmonic current spectrum corresponding to the overall extended harmonic domain dynamic model and the electromagnetic transient model of the doubly-fed asynchronous wind turbine according to Embodiment 1 of the present disclosure at a certain time point under varying wind speeds;

图8为本公开实施例1的双馈异步风力发电机的整体扩展谐波域动态模型在变化风速下发电机38次、42次、79次、81次定子谐波电流的动态变化过程。8 is the dynamic change process of the 38th, 42nd, 79th, and 81st generator stator harmonic currents of the overall extended harmonic domain dynamic model of the doubly-fed asynchronous wind turbine according to Embodiment 1 of the present disclosure.

具体实施方式：Detailed ways:

下面结合附图与实施例对本公开作进一步说明。The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

应该指出，以下详细说明都是示例性的，旨在对本公开提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本公开所属技术领域的普通技术人员通常理解的相同含义。It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图限制根据本公开的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，当在本说明书中使用术语“包含”和/或“包括”时，其指明存在特征、步骤、操作、器件、组件和/或它们的组合。需要说明的是，在不冲突的情况下，本公开中的各个实施例及实施例中的特征可以相互组合。下面将结合附图对实施例进行详细描述。It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof. It should be noted that the various embodiments in the present disclosure and the features of the embodiments may be combined with each other without conflict. The embodiments will be described in detail below with reference to the accompanying drawings.

实施例1Example 1

在一个或多个实施方式中公开的技术方案中，如图1所示，基于扩展谐波域模型的风力发电系统输出监测方法，包括如下步骤:In the technical solutions disclosed in one or more embodiments, as shown in FIG. 1 , a method for monitoring the output of a wind power generation system based on an extended harmonic domain model includes the following steps:

S1、分别针对风力发电机、变换器的网侧系统和直流母线建立时域模型；S1. Establish a time domain model for the grid-side system of the wind turbine, the converter and the DC bus respectively;

S2、分别获取风力发电机、变换器的网侧系统和直流母线的电气参数数据；S2. Obtain the electrical parameter data of the wind turbine, the grid-side system of the converter and the DC bus, respectively;

S3、针对建立的时域模型，通过矢量变换以及频域定常化，根据获取的电气参数数据分别针对风力发电机、变换器的网侧系统和直流母线建立扩展谐波域模型；S3. According to the established time domain model, through vector transformation and frequency domain normalization, according to the obtained electrical parameter data, an extended harmonic domain model is respectively established for the wind turbine, the grid-side system of the converter and the DC bus;

S4、整合建立的扩展谐波域模型，以电机定子端电压为输入，输出为电机定子电流、转子电流、网侧电流和变换器中直流母线电压的各次谐波分量，得到双馈异步风力发电机的整体扩展谐波域动态模型，利用所述模型对风力发电系统的输出状态进行监测。根据模型可以实现对风力发电系统有效监测和准确评估。S4. Integrate the established extended harmonic domain model, take the motor stator terminal voltage as the input, and the output is the motor stator current, rotor current, grid-side current and the harmonic components of the DC bus voltage in the converter, and obtain the doubly-fed asynchronous wind power The overall extended harmonic domain dynamic model of the generator is used to monitor the output state of the wind power generation system. According to the model, the effective monitoring and accurate evaluation of the wind power generation system can be realized.

本实施例采用频域定常化建立了双馈风力发电系统“频域定常化”后的扩展谐波域模型，既适用于表征暂态情况下的谐波动态，又可用于分析稳态情况下整个发电系统内部变量的谐波特征，通过本实施例的模型能够对风力发电系统实现有效监测和准确评估的目的。In this example, the frequency domain normalization is used to establish an extended harmonic domain model of the doubly-fed wind power generation system after the "frequency domain normalization", which is not only suitable for characterizing the harmonic dynamics under transient conditions, but also for analyzing the steady state conditions. The harmonic characteristics of the internal variables of the entire power generation system can be effectively monitored and accurately evaluated for the wind power generation system through the model in this embodiment.

1)针对风力发电机建立基于扩展谐波域的双馈异步发电机动态模型的方法，可以如下：1) The method for establishing a dynamic model of a doubly-fed asynchronous generator based on an extended harmonic domain for a wind turbine can be as follows:

S101、针对双馈异步发电机，将定子电压、定子电流、转子电压和转子电流采用空间矢量描述。根据双馈异步发电机的dq等效电路模型，以定子dq轴电流和转子dq轴电流为状态量，以定子dq轴电压和转子dq轴电压为输入量，建立双馈异步发电机的状态空间方程；S101. For the doubly-fed asynchronous generator, describe the stator voltage, stator current, rotor voltage and rotor current using space vectors. According to the dq equivalent circuit model of the DFIG, the state space of the DFIG is established with the stator dq-axis current and rotor dq-axis current as state quantities, and the stator dq-axis voltage and rotor dq-axis voltage as input quantities. equation;

S102、根据双馈异步发电机的状态空间方程和扩展谐波域核心方程，采用频域定常化方法获得双馈异步发电机的扩展谐波域动态模型；S102. According to the state space equation and the extended harmonic domain core equation of the doubly-fed asynchronous generator, a frequency domain normalization method is used to obtain an extended harmonic domain dynamic model of the doubly-fed asynchronous generator;

S103、获取风力发电机的电气参数数据，确定双馈异步发电机的谐波状态空间模型的系数，建立最终的双馈异步发电机的谐波状态空间模型。S103 , obtaining electrical parameter data of the wind turbine, determining the coefficients of the harmonic state space model of the doubly-fed asynchronous generator, and establishing a final harmonic state space model of the doubly-fed asynchronous generator.

其中，可选的，频域定常化方法具体为：在原状态空间的左侧新增状态量的微分项；各状态量和输入量通过双边傅里叶分解成为谐波空间矢量；建立包含谐波空间矢量各次谐波的傅里叶系数的列向量，对应作为状态量和输入量；根据状态量和输入量的维度变化调整原状态空间的系数矩阵。Wherein, optionally, the frequency domain normalization method is specifically: adding a differential term of the state quantity on the left side of the original state space; each state quantity and input quantity are decomposed into a harmonic space vector through bilateral Fourier transformation; The column vector of the Fourier coefficients of each harmonic of the space vector corresponds to the state quantity and the input quantity; the coefficient matrix of the original state space is adjusted according to the dimensional changes of the state quantity and the input quantity.

本实施例建立的双馈异步发电机的扩展谐波域动态模型是考虑双馈异步发电机定子电压、定子电流、转子电压和转子电流在dq坐标系下各次谐波的状态空间模型，既适用于表征暂态情况下的谐波动态，又可用于分析稳态情况下发电机定子输出电流的谐波特征，达到监测和准确评估的目的。The extended harmonic domain dynamic model of the DFIG established in this embodiment is a state space model that considers the various harmonics of the DFIG stator voltage, stator current, rotor voltage and rotor current in the dq coordinate system. It is suitable for characterizing the harmonic dynamics under transient conditions, and can also be used to analyze the harmonic characteristics of generator stator output current under steady-state conditions, so as to achieve the purpose of monitoring and accurate evaluation.

S101中，双馈异步发电机的定子电压、定子电流、转子电压和转子电流采用空间矢量描述，分别为

Figure BDA0002541467000000071
In S101, the stator voltage, stator current, rotor voltage and rotor current of the DFIG are described by space vectors, which are respectively
Figure BDA0002541467000000071

可选的，本实施例的双馈异步发电机的dq等效电路模型可以如图2所示，等效电路模型中包含发电机定子电阻Rs和发电机转子电阻Rr，发电机定子电感Ls、转子电感Lr和励磁电感Lm，三个电感通过定子漏感Lσs、转子漏感Lσr实现关联，满足如下公式：Optionally, the dq equivalent circuit model of the doubly-fed asynchronous generator in this embodiment may be as shown in FIG. 2 . The equivalent circuit model includes the generator stator resistance R s and the generator rotor resistance R r , and the generator stator inductance. L s , rotor inductance L r and excitation inductance L m , the three inductances are related by stator leakage inductance L σs and rotor leakage inductance L σr , which satisfy the following formula:

Figure BDA0002541467000000081
Figure BDA0002541467000000081

图2中，对d轴和q轴的分量分别通过等效电路表示，其中vds和vqs分别是定子电压

Figure BDA0002541467000000082
的d轴和q轴的分量；ids和iqs分别是定子电流
Figure BDA0002541467000000083
的d轴和q轴分量；vdr和vqr分别是转子电压
Figure BDA0002541467000000084
的d轴和q轴分量；idr和iqr分别是转子电流
Figure BDA0002541467000000085
的d轴和q轴分量。In Figure 2, the components for the d-axis and q-axis are represented by equivalent circuits, respectively, where v ds and v qs are the stator voltages, respectively
Figure BDA0002541467000000082
d- and q-axis components of ; i ds and i qs are the stator currents, respectively
Figure BDA0002541467000000083
d-axis and q-axis components of ; vdr and vqr are the rotor voltages, respectively
Figure BDA0002541467000000084
d-axis and q-axis components of ; i dr and i qr are the rotor currents, respectively
Figure BDA0002541467000000085
The d- and q-axis components of .

以定子dq轴电流和转子dq轴电流为状态量，定子dq轴电压和转子dq轴电压为输入量，建立双馈异步发电机的状态空间方程，可以具体如下：Taking the stator dq-axis current and rotor dq-axis current as state quantities, and the stator dq-axis voltage and rotor dq-axis voltage as input quantities, the state space equation of the doubly-fed asynchronous generator is established, which can be specified as follows:

Figure BDA0002541467000000086
Figure BDA0002541467000000086

式中，ωm是发电机转子电角频率，ωs是发电机定子角频率，

Figure BDA0002541467000000088
是ωs的托普利兹矩阵形式(Toeplitz-type matrix)。where ω m is the generator rotor electrical angular frequency, ω s is the generator stator angular frequency,
Figure BDA0002541467000000088
is the Toeplitz-type matrix of ω s .

步骤102中，扩展谐波域核心方程，可以具体为:In step 102, the extended harmonic domain core equation can be specifically:

Figure BDA0002541467000000087
Figure BDA0002541467000000087

Y＝CX+EUY=CX+EU

根据步骤S101所得的状态空间方程，代入扩展谐波域核心方程实现频域定常化。According to the state space equation obtained in step S101, the extended harmonic domain core equation is substituted to realize frequency domain normalization.

将各状态量和输入量通过双边傅里叶分解成为谐波空间矢量，每个变量的结构表现为列向量

Figure BDA0002541467000000091
向量内包含各次谐波的傅里叶系数。原状态空间的系数矩阵跟随状态量和输入量的维度调整。得到同步旋转坐标系中双馈异步发电机的谐波状态空间模型表示为：The state quantities and input quantities are decomposed into harmonic space vectors through bilateral Fourier transformation, and the structure of each variable is expressed as a column vector
Figure BDA0002541467000000091
The vector contains the Fourier coefficients for each harmonic. The coefficient matrix of the original state space is adjusted according to the dimensions of the state quantity and the input quantity. The harmonic state space model of the doubly-fed asynchronous generator in the synchronous rotating coordinate system is obtained as:

Figure BDA0002541467000000095
Figure BDA0002541467000000095

Figure BDA0002541467000000092
Figure BDA0002541467000000092

Figure BDA0002541467000000093
Figure BDA0002541467000000093

其中，D由4个微分矩阵D0＝diag{-jhω0 … -jω0 0 -jω0 … jhω0}以对角线形式组成，ω0是发电机定子的电角速度，为恒定值，单位rad/s；I是单位矩阵，其阶数为(2hmax+1)，hmax是每个变量包含谐波次数的数量；

Figure BDA0002541467000000094
是发电机转子电角频率ωm的托普利兹矩阵形式，其中的元素由转子电角频率对应各次谐波的傅里叶系数决定。where D consists of 4 differential matrices D 0 =diag{-jhω 0 … -jω 0 0 -jω 0 … jhω 0 } in diagonal form, ω 0 is the electrical angular velocity of the generator stator, which is a constant value in units rad/s; I is the identity matrix whose order is (2h max +1), and h max is the number of harmonic orders each variable contains;
Figure BDA0002541467000000094
is the Toeplitz matrix form of the generator rotor electrical angular frequency ω m , the elements of which are determined by the Fourier coefficients of the rotor electrical angular frequency corresponding to each harmonic.

步骤S2中，针对风力发电机，需要获取的风力发电机的电气参数数据包括：风力发电机的电阻、电感和漏感，电阻包括定子电阻RS和转子电阻Rr，电感包括发电机定子电感Ls、转子电感Lr和励磁电感Lm，漏感包括定子漏感Lσs和转子漏感Lσr。In step S2, for the wind turbine, the electrical parameter data of the wind turbine to be acquired includes: the resistance, inductance and leakage inductance of the wind turbine, the resistance includes the stator resistance R S and the rotor resistance R r , and the inductance includes the generator stator inductance. L s , rotor inductance L r and excitation inductance L m , the leakage inductance includes stator leakage inductance L σs and rotor leakage inductance L σr .

根据获取的风力发电机的电气参数数据确定双馈异步发电机的谐波状态空间模型的系数，从而建立双馈异步发电机的谐波状态空间模型。The coefficients of the harmonic state space model of the doubly-fed asynchronous generator are determined according to the acquired electrical parameter data of the wind turbine, thereby establishing the harmonic state space model of the doubly-fed asynchronous generator.

2)针对背靠背变换器网侧系统建立基于扩展谐波域的变换器网侧动态模型的方法，可以如下：2) The method of establishing a grid-side dynamic model of the converter based on the extended harmonic domain for the grid-side system of the back-to-back converter can be as follows:

本实施例以两电平拓扑背靠背变换器进行说明，图3是本公开实施例提供的背靠背变换器的网侧系统和直流母线的简化模型图。假设直流侧电容足够大，可以实现机侧和网侧系统的独立控制，网侧系统包括网侧变换器、网侧滤波器和电网系统共同组成。This embodiment is described with a two-level topology back-to-back converter. FIG. 3 is a simplified model diagram of a grid-side system and a DC bus of the back-to-back converter provided by the embodiment of the present disclosure. Assuming that the DC-side capacitance is large enough, the independent control of the machine-side and grid-side systems can be realized. The grid-side system includes the grid-side converter, the grid-side filter and the grid system.

步骤201、根据网侧系统等效电路模型及理想双向开关函数，分别建立网侧变换器模型，网侧变换器连接到电网的三相感性滤波器模型。对两个子模型中的三相变量进行矢量变换，然后整合为同步旋转坐标系中网侧系统以状态空间方程形式描述的动态数学模型。Step 201 , according to the grid-side system equivalent circuit model and the ideal bidirectional switching function, respectively establish grid-side converter models, and the grid-side converters are connected to the three-phase inductive filter model of the grid. The three-phase variables in the two sub-models are transformed into vectors, and then integrated into a dynamic mathematical model described by the state-space equation of the grid-side system in the synchronous rotating coordinate system.

步骤202、将网侧系统的状态空间方程转化至扩展谐波域中，频域定常化方法具体为：在原状态空间方程的左侧新增状态量的微分项；各状态量和输入量通过双边傅里叶分解成为谐波空间矢量，结构表现为列向量，向量内包含各次谐波的傅里叶系数；原状态空间的系数矩阵跟随状态量和输入量的维度做出相应调整。Step 202: Transform the state space equation of the grid-side system into the extended harmonic domain, and the frequency domain normalization method is specifically: adding a differential term of the state quantity on the left side of the original state space equation; The Fourier decomposition becomes a harmonic space vector, and the structure is expressed as a column vector, and the vector contains the Fourier coefficients of each harmonic; the coefficient matrix of the original state space is adjusted according to the dimensions of the state quantity and the input quantity.

以电网输出电流为状态量，根据扩展谐波源核心方程，对网侧系统的状态空间方程中的各状态量和输入量采用双边傅里叶分解成为谐波空间矢量，获得背靠背变换器网侧系统的谐波状态空间模型，即获得扩展谐波域的变换器网侧系统动态模型，如下：Taking the output current of the power grid as the state quantity, according to the core equation of the extended harmonic source, each state quantity and input quantity in the state space equation of the grid-side system are decomposed into harmonic space vectors by bilateral Fourier decomposition, and the grid-side back-to-back converter is obtained. The harmonic state space model of the system, that is, the dynamic model of the grid-side system of the converter in the extended harmonic domain, is as follows:

Figure BDA0002541467000000111
Figure BDA0002541467000000111

式中，Rg是滤波器的电阻，Lg是滤波器的电感；

Figure BDA0002541467000000112
是发电机定子角速度的托普利兹矩阵；理想双向开关函数
Figure BDA0002541467000000113
和
Figure BDA0002541467000000114
分别表示网侧变换器A、B、C三相上下桥臂的开关状态；D由4个微分矩阵D0＝diag{-jhω0 … -jω0 0 -jω0 … jhω0}以对角线形式组成；I是单位矩阵，阶数为(2hmax+1)；
Figure BDA0002541467000000115
和
Figure BDA0002541467000000116
幅值相等，相位相反，分别代表直流母线上两个电容的对地电压；Vds和Vqs分别对应电网电压(定子电压)
Figure BDA0002541467000000117
的d轴和q轴的分量；Idg和Iqg分别对应网侧变换器输入电网的电流的d轴和q轴的分量；C3/2是将abc三相坐标系变量转换到dq坐标系的变换矩阵，表示为：where R g is the resistance of the filter, and L g is the inductance of the filter;
Figure BDA0002541467000000112
is the Toeplitz matrix of the generator stator angular velocity; the ideal bidirectional switching function
Figure BDA0002541467000000113
and
Figure BDA0002541467000000114
respectively represent the switching states of the upper and lower bridge arms of the grid -side converters A, B, and C ; Form composition; I is the identity matrix, the order is (2h max +1);
Figure BDA0002541467000000115
and
Figure BDA0002541467000000116
The amplitudes are equal and the phases are opposite, respectively representing the ground voltage of the two capacitors on the DC bus; V ds and V qs correspond to the grid voltage (stator voltage) respectively
Figure BDA0002541467000000117
I dg and I qg correspond to the d-axis and q-axis components of the current input to the grid by the grid-side converter, respectively; C 3/2 is to convert the abc three-phase coordinate system variable to the dq coordinate system The transformation matrix of , expressed as:

Figure BDA0002541467000000118
Figure BDA0002541467000000118

式中，θs表示定子电角位置。In the formula, θ s represents the stator electrical angle position.

可选的，将网侧变换器的时域开关函数

Figure BDA0002541467000000119
和
Figure BDA00025414670000001110
通过双边傅里叶分解获得扩展谐波域下的开关函数Sx：获取定子角频率和开关函数对应各次谐波的傅里叶系数，确定扩展谐波域下的开关函数Sx的元素；开关函数Sx由开关调制方法决定，在扩展谐波域中表现为Toeplitz矩阵形式，表示为：Optionally, the time-domain switching function of the grid-side converter
Figure BDA0002541467000000119
and
Figure BDA00025414670000001110
Obtain the switching function S x in the extended harmonic domain through bilateral Fourier decomposition: obtain the Fourier coefficients of the stator angular frequency and the switching function corresponding to each harmonic, and determine the elements of the switching function S x in the extended harmonic domain; The switching function S x is determined by the switching modulation method, and is expressed in the form of a Toeplitz matrix in the extended harmonic domain, which is expressed as:

Figure BDA0002541467000000121
Figure BDA0002541467000000121

本实施例以Toeplitz矩阵形式在扩展谐波域模型中体现了开关过程产生的谐波含量，同时还考虑了开关调制方法的特性。This embodiment reflects the harmonic content generated by the switching process in the extended harmonic domain model in the form of a Toeplitz matrix, and also considers the characteristics of the switching modulation method.

本实施例明确考虑了电力电子器件的开关过程，开关函数经傅里叶分解后可很容易在方程中体现，更适用于反应风机内部的动态响应，跟踪定子谐波电流的动态过程。This embodiment explicitly considers the switching process of the power electronic device, and the switching function can be easily reflected in the equation after Fourier decomposition, which is more suitable for reflecting the dynamic response inside the fan and tracking the dynamic process of the stator harmonic current.

3)针对背靠背变换器直流母线建立基于扩展谐波域的变换器直流母线动态模型的方法，可以如下：3) The method for establishing the DC bus dynamic model of the converter based on the extended harmonic domain for the DC bus of the back-to-back converter can be as follows:

针对两电平拓扑背靠背变换器，直流母线连接转子侧变换器和网侧变换器，各支路电流流向如图3所示。For the two-level topology back-to-back converter, the DC bus connects the rotor-side converter and the grid-side converter, and the current flow of each branch is shown in Figure 3.

S301、根据两电平拓扑背靠背变换器中各支路电流流向和理想双向开关函数，获得直流母线的直流输入和直流输出关系。获取直流母线的电容参数，建立直流母线的动态数学模型。再将转子变量通过逆旋转变换转换到定子坐标系中，对三相变量进行矢量变换，建立同步旋转坐标系中直流母线的状态空间方程。S301 , according to the current flow of each branch in the two-level topology back-to-back converter and the ideal bidirectional switching function, obtain the relationship between the DC input and the DC output of the DC bus. Obtain the capacitance parameters of the DC bus, and establish a dynamic mathematical model of the DC bus. Then, the rotor variables are transformed into the stator coordinate system through the inverse rotation transformation, and the three-phase variables are vectorized to establish the state space equation of the DC bus in the synchronous rotating coordinate system.

S302、根据扩展谐波源核心方程，在原状态空间方程的左侧新增状态量的微分项；对直流母线的状态空间方程中的各状态量和输入量采用双边傅里叶分解成为谐波空间矢量，获得背靠背变换器直流母线的谐波状态空间模型，即获得扩展谐波域的变换器直流母线动态模型，表示为：S302. According to the core equation of the extended harmonic source, a differential term of the state quantity is added to the left side of the original state space equation; each state quantity and input quantity in the state space equation of the DC bus are decomposed into a harmonic space by bilateral Fourier decomposition vector, obtain the harmonic state space model of the DC bus of the back-to-back converter, that is, obtain the dynamic model of the DC bus of the converter in the extended harmonic domain, which is expressed as:

Figure BDA0002541467000000131
Figure BDA0002541467000000131

式中，

Figure BDA0002541467000000132
和
Figure BDA0002541467000000133
幅值相等，相位相反，分别代表直流母线上两个电容的对地电压；C1、C2为直流母线上大小相等的对地电容；理想双向开关函数
Figure BDA0002541467000000134
Figure BDA0002541467000000135
分别表示网侧变换器A、B、C三相上下桥臂的开关状态；理想双向开关函数
Figure BDA0002541467000000136
分别表示转子侧变换器A、B、C三相上下桥臂的开关状态；Idg和Iqg分别对应网侧变换器输入电网的电流的d轴和q轴的分量；Idr和Iqr分别对应转子输入转子侧变换器的电流的d轴和q轴的分量；C3/2是将abc三相坐标系变量转换到dq坐标系的变换矩阵，上标-1表示逆矩阵。In the formula,
Figure BDA0002541467000000132
and
Figure BDA0002541467000000133
The amplitudes are equal and the phases are opposite, respectively representing the ground-to-ground voltage of the two capacitors on the DC bus; C 1 and C 2 are the equal-sized ground-to-ground capacitors on the DC bus; the ideal bidirectional switching function
Figure BDA0002541467000000134
Figure BDA0002541467000000135
respectively represent the switching states of the upper and lower bridge arms of the grid-side converters A, B, and C; the ideal bidirectional switching function
Figure BDA0002541467000000136
respectively represent the switching states of the upper and lower bridge arms of the three-phase converters A, B, and C on the rotor side; I dg and I qg correspond to the d-axis and q-axis components of the current input to the grid by the grid-side converter; I dr and I qr respectively Corresponding to the d-axis and q-axis components of the current input to the rotor-side converter by the rotor; C 3/2 is the transformation matrix that converts the abc three-phase coordinate system variable to the dq coordinate system, and the superscript -1 represents the inverse matrix.

其中，M-1是旋转变换矩阵的逆，具体表示为：Among them, M -1 is the inverse of the rotation transformation matrix, which is specifically expressed as:

Figure BDA0002541467000000137
Figure BDA0002541467000000137

其中，θm为转子电角位置。Among them, θ m is the rotor electrical angle position.

将转子侧变换器时域开关函数

Figure BDA0002541467000000138
以及网侧变换器的时域开关函数
Figure BDA0002541467000000141
通过双边傅里叶分解，获得开关函数Sx，本步骤中扩展谐波域下的开关函数Sx的确定方法与步骤S202中的开关函数Sx相同，开关函数Sx作为扩展谐波域的变换器直流母线动态模型
Figure BDA0002541467000000142
Figure BDA0002541467000000143
提供取值。The rotor-side converter time-domain switching function
Figure BDA0002541467000000138
and the time-domain switching function of the grid-side converter
Figure BDA0002541467000000141
Through bilateral Fourier decomposition, the switching function S x is obtained. The method for determining the switching function S x in the extended harmonic domain in this step is the same as the switching function S x in step S202 , and the switching function S x is used as the extended harmonic domain. Converter DC bus dynamic model
Figure BDA0002541467000000142
Figure BDA0002541467000000143
Provide a value.

步骤4中，是对上述1)-3)所获得的模型整合，获得双馈风力发电系统动态模型，具体整合的方法可以如下：In step 4, the models obtained in the above 1)-3) are integrated to obtain the dynamic model of the doubly-fed wind power generation system. The specific integration method can be as follows:

由于xd与xq存在90°相位差，两者的关系式可表示为xq＝Exd，其中，Since there is a 90° phase difference between x d and x q , the relationship between the two can be expressed as x q =Ex d , where,

Figure BDA0002541467000000144
Figure BDA0002541467000000144

则简化模型时，可只提取xd为变量。Then when simplifying the model, only x d can be extracted as a variable.

平衡系统中，背靠背变换器中的直流母线上满足

Figure BDA0002541467000000145
直流母线电压
Figure BDA0002541467000000146
In a balanced system, the DC bus in the back-to-back converter satisfies
Figure BDA0002541467000000145
DC bus voltage
Figure BDA0002541467000000146

将上述获得的基于扩展谐波域的双馈异步发电机动态模型、背靠背变换器网侧系统动态模型和直流母线动态模型进行整合，使模型输入为电机定子端电压，输出为电机定子电流、转子电流、网侧电流和变换器中直流母线电压的各次谐波分量，即得到双馈异步风力发电机的整体扩展谐波域动态模型，具体表示为：Integrate the dynamic model of the doubly-fed asynchronous generator based on the extended harmonic domain, the dynamic model of the grid-side system of the back-to-back converter, and the dynamic model of the DC bus, so that the input of the model is the motor stator terminal voltage, and the output is the motor stator current and rotor. The harmonic components of the current, grid-side current and DC bus voltage in the converter can be obtained to obtain the overall extended harmonic domain dynamic model of the doubly-fed asynchronous wind turbine, which is specifically expressed as:

Figure BDA0002541467000000147
Figure BDA0002541467000000147

其中，系数矩阵中各元素表达式分别表示为：Among them, the expression of each element in the coefficient matrix is expressed as:

Figure BDA0002541467000000148
Figure BDA0002541467000000148

Figure BDA0002541467000000151
Figure BDA0002541467000000151

Figure BDA0002541467000000152
Figure BDA0002541467000000152

Figure BDA0002541467000000153
Figure BDA0002541467000000153

Figure BDA0002541467000000154
Figure BDA0002541467000000154

Figure BDA0002541467000000155
Figure BDA0002541467000000155

Figure BDA0002541467000000156
Figure BDA0002541467000000156

Figure BDA0002541467000000157
Figure BDA0002541467000000157

为了说明本实施例的效果，进行了仿真实验：In order to illustrate the effect of this embodiment, a simulation experiment was carried out:

利用本实施例分析双馈风力发电系统在稳态和暂态情况下的谐波特性。图4给出了本实施例在恒定风速下的谐波稳态分析结果(EHD模型)与电磁暂态模型(EMT模型)仿真结果的对比，解析值与仿真值具有较好的一致性。This embodiment is used to analyze the harmonic characteristics of the doubly-fed wind power generation system under steady-state and transient conditions. FIG. 4 shows the comparison between the harmonic steady state analysis results (EHD model) and the electromagnetic transient model (EMT model) simulation results under constant wind speed in this embodiment, and the analytical values are in good agreement with the simulated values.

图5给出了本实施例与电磁暂态模型、平均模型在变化风速下直流母线电压变化的对比，本实施例可及时跟踪风电系统内直流母线电压变量的动态响应；图6给出了本实施例与电磁暂态模型、平均模型在变化风速下定子基频电流的对比，本实施例可反映电流的冲击式不稳定性现象；图7给出了本实施例与电磁暂态模型在变化风速下某个时间点对应的发电机定子谐波电流频谱对比图；图8给出了本实施例变化风速下发电机38次、42次、79次、81次定子谐波电流的动态变化过程。可见，本实施例的算法明确考虑开关过程的数学模型更适用于反应风机内部的动态响应，跟踪定子谐波电流的动态过程,在稳态和暂态下均有较高的准确性，能够精确反映各次谐波的冲击跳变，及时反馈电能质量情况。Fig. 5 shows the comparison of the DC bus voltage variation of this embodiment with the electromagnetic transient model and the average model under changing wind speeds. This embodiment can track the dynamic response of the DC bus voltage variable in the wind power system in time; Fig. 6 shows this embodiment. The comparison between the embodiment and the electromagnetic transient model and the average model of the stator fundamental frequency current under the changing wind speed shows that the present embodiment can reflect the shock-type instability phenomenon of the current; FIG. 7 shows the variation between the present embodiment and the electromagnetic transient model. Figure 8 shows the dynamic change process of the 38th, 42nd, 79th, and 81st generator stator harmonic currents under the changing wind speed of this embodiment. . It can be seen that the algorithm of this embodiment explicitly considers the mathematical model of the switching process, which is more suitable for reflecting the dynamic response inside the fan and tracking the dynamic process of the stator harmonic current. It has high accuracy in steady state and transient state, and can accurately Reflect the impact jump of each harmonic, and timely feedback the power quality.

实施例2Example 2

本实施例提供基于扩展谐波域模型的风力发电系统输出监测系统，包括：This embodiment provides a wind power generation system output monitoring system based on an extended harmonic domain model, including:

时域模型建立模块：被配置用于分别针对风力发电机、变换器的网侧系统和直流母线建立时域模型；Time-domain model building module: configured to build time-domain models for wind turbines, grid-side systems of converters, and DC bus, respectively;

数据获取模块：被配置用于分别获取风力发电机、变换器的网侧系统和直流母线的电气参数数据；Data acquisition module: configured to acquire the electrical parameter data of the wind turbine, the grid-side system of the converter and the DC bus, respectively;

扩展谐波域模型建立模块：被配置用于针对建立的时域模型，通过矢量变换以及频域定常化，根据获取的电气参数数据分别针对风力发电机、变换器的网侧系统和直流母线建立扩展谐波域模型；Extended harmonic domain model building module: configured for the established time domain model, through vector transformation and frequency domain normalization, according to the acquired electrical parameter data for wind turbines, converter grid-side systems and DC bus. Extended harmonic domain model;

整合监测模块：被配置用于整合建立的扩展谐波域模型，以电机定子端电压为输入，输出为电机定子电流、转子电流、网侧电流和变换器中直流母线电压的各次谐波分量，得到双馈异步风力发电机的整体扩展谐波域动态模型，利用所述模型对风力发电系统的输出状态进行监测。Integrated monitoring module: It is configured to integrate the established extended harmonic domain model, taking the motor stator terminal voltage as the input, and the output is the motor stator current, rotor current, grid-side current and the DC bus voltage in the converter. The harmonic components of each order , obtain the overall extended harmonic domain dynamic model of the doubly-fed asynchronous wind turbine, and use the model to monitor the output state of the wind power generation system.

实施例3Example 3

本实施例提供一种电子设备，包括存储器和处理器以及存储在存储器上并在处理器上运行的计算机指令，所述计算机指令被处理器运行时，完成实施例1的方法所述的步骤。This embodiment provides an electronic device, including a memory, a processor, and computer instructions stored in the memory and executed on the processor, and when the computer instructions are executed by the processor, the steps described in the method of Embodiment 1 are completed.

实施例4Example 4

本实施例提供一种计算机可读存储介质，用于存储计算机指令，所述计算机指令被处理器执行时，完成实施例1的方法所述的步骤。This embodiment provides a computer-readable storage medium for storing computer instructions. When the computer instructions are executed by a processor, the steps described in the method of Embodiment 1 are completed.

以上所述仅为本公开的优选实施例而已，并不用于限制本公开，对于本领域的技术人员来说，本公开可以有各种更改和变化。凡在本公开的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.

上述虽然结合附图对本公开的具体实施方式进行了描述，但并非对本公开保护范围的限制，所属领域技术人员应该明白，在本公开的技术方案的基础上，本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本公开的保护范围以内。Although the specific embodiments of the present disclosure are described above in conjunction with the accompanying drawings, they do not limit the protection scope of the present disclosure. Those skilled in the art should understand that on the basis of the technical solutions of the present disclosure, those skilled in the art do not need to pay creative efforts. Various modifications or variations that can be made are still within the protection scope of the present disclosure.

Claims (7)

1. The wind power generation system output monitoring method based on the extended harmonic domain model is characterized by comprising the following steps of:
respectively establishing time domain models aiming at a wind driven generator, a network side system of a converter and a direct current bus;
respectively acquiring electrical parameter data of a wind driven generator, a network side system of a converter and a direct current bus;
aiming at the established time domain model, respectively establishing an extended harmonic domain model aiming at a wind driven generator, a network side system of a converter and a direct current bus according to the obtained electrical parameter data through vector transformation and frequency domain normalization;
the method for establishing the doubly-fed asynchronous generator dynamic model based on the extended harmonic domain for the wind driven generator comprises the following steps:
according to a dq equivalent circuit model of the doubly-fed asynchronous generator, a state space equation of the doubly-fed asynchronous generator is established by taking stator current and rotor current as state quantities and taking stator voltage and rotor voltage as input quantities, and the method specifically comprises the following steps:
Figure FDF0000016945170000011
in the formula, omegamIs the electrical angular frequency, omega, of the generator rotorsIs the angular frequency of the stator of the generator,
Figure FDF0000016945170000012
is omegasOf Toplitz matrix form idsAnd iqsAre respectively stator currents
Figure FDF0000016945170000021
D-axis and q-axis components of (1); i.e. idrAnd iqrAre respectively rotor currents
Figure FDF0000016945170000022
D-axis and q-axis components of (1); rsIs the generator stator resistance, RrIs the generator rotor resistance, Ls、Lr、LmThe inductance of the stator, the inductance of the rotor and the excitation inductance of the generator are respectively; v. ofdsAnd vqsAre respectively stator voltages
Figure FDF0000016945170000023
The d-axis and q-axis components of (a); v. ofdrAnd vqrAre respectively rotor voltage
Figure FDF0000016945170000024
D-axis and q-axis components of (1);
obtaining an extended harmonic domain dynamic model of the doubly-fed asynchronous generator by adopting a frequency domain normalization method according to a state space equation and an extended harmonic domain core equation of the doubly-fed asynchronous generator;
acquiring electrical parameter data of the wind driven generator, determining coefficients of a harmonic state space model of the doubly-fed asynchronous generator, and establishing a final harmonic state space model of the doubly-fed asynchronous generator;
the method for establishing the converter grid-side dynamic model based on the extended harmonic domain for the back-to-back converter grid-side system comprises the following steps:
establishing a grid-side converter model and a three-phase inductive filter model of the grid-side converter connected to the power grid according to the equivalent circuit model of the grid-side system and the ideal bidirectional switch function;
carrying out vector transformation on three-phase variables in the network side converter model and the three-phase inductive filter model, and then integrating the three-phase variables into a dynamic mathematical model described by a network side system in a synchronous rotating coordinate system in a state space equation form;
converting a state space equation of the network side system into an extended harmonic domain by adopting a frequency domain constant method;
the method for establishing the converter direct-current bus dynamic model based on the extended harmonic domain for the direct-current bus comprises the following steps:
obtaining the relation between the direct current input and the direct current output of the direct current bus according to an ideal bidirectional switching function and a two-level topology back-to-back converter; acquiring capacitance parameters of the direct current bus, and establishing a dynamic mathematical model of the direct current bus; converting the rotor variable into a stator coordinate system through inverse rotation transformation, performing vector transformation on the three-phase variable, and establishing a state space equation of a direct current bus in a synchronous rotation coordinate system;
taking the direct-current bus capacitor voltage as a state quantity, and adding a differential term of the state quantity on the left side of an original state space equation according to an extended harmonic source core equation; performing bilateral Fourier decomposition on each state quantity and input quantity in a state space equation of the direct current bus to obtain a harmonic wave state space model of the direct current bus of the back-to-back converter, namely obtaining a converter direct current bus dynamic model of an extended harmonic wave domain, wherein the harmonic wave state space model is expressed as follows:
Figure FDF0000016945170000031
in the formula (I), the compound is shown in the specification,
Figure FDF0000016945170000032
and
Figure FDF0000016945170000033
the amplitudes are equal, the phases are opposite, and the amplitudes represent the voltages to the ground of two capacitors on the direct current bus respectively; c1、C2The direct current bus is provided with the same capacitance to ground; ideal bidirectional switching function
Figure FDF0000016945170000034
Figure FDF0000016945170000035
Respectively showing the switching states of three-phase upper and lower bridge arms of the grid-side converter A, B, C; ideal bidirectional switching function
Figure FDF0000016945170000036
Respectively showing the switching states of the three-phase upper and lower arms of rotor-side converter A, B, C; i isdgAnd IqgRespectively corresponding to the components of a d axis and a q axis of the current input into the power grid by the grid-side converter; i isdrAnd IqrComponents of d-axis and q-axis of the current input to the rotor-side converter corresponding to the rotor, respectively; c3/2Converting variables of an abc three-phase coordinate system into a transformation matrix of a dq coordinate system, and superscript-1 represents an inverse matrix; m-1Is the inverse of the rotation transformation matrix;
and integrating the established extended harmonic domain model, taking the terminal voltage of a motor stator as input, and outputting the terminal voltage of the motor stator, the rotor current, the network side current and each subharmonic component of the direct current bus voltage in the converter to obtain an integral extended harmonic domain dynamic model of the doubly-fed asynchronous wind driven generator, which is specifically expressed as follows:
Figure FDF0000016945170000037
wherein, each element expression in the coefficient matrix is respectively expressed as:
Figure FDF0000016945170000041
Figure FDF0000016945170000042
Figure FDF0000016945170000043
Figure FDF0000016945170000044
Figure FDF0000016945170000045
Figure FDF0000016945170000046
Figure FDF0000016945170000047
Figure FDF0000016945170000051
and monitoring the output state of the wind power generation system by using the integral extended harmonic domain dynamic model.
2. The method according to claim 1, wherein the method comprises the following steps: the method for frequency domain stationary normalization comprises the following steps of obtaining a dynamic model of an extended harmonic domain of a doubly-fed asynchronous generator, specifically: a differential term of the state quantity is newly added on the left side of the original state space; each state quantity and input quantity are decomposed into harmonic space vectors through bilateral Fourier; establishing a column vector of Fourier coefficients containing each subharmonic of a harmonic space vector, and correspondingly taking the column vector as a state quantity and an input quantity; and adjusting the coefficient matrix of the original state space according to the dimension changes of the state quantity and the input quantity.
3. The method according to claim 1, wherein the method comprises the following steps: for the wind driven generator, the electrical parameter data of the wind driven generator required to be acquired comprises: the wind driven generator comprises a resistor, an inductor and a leakage inductor, wherein the resistor comprises a stator resistor and a rotor resistor, the inductor comprises a generator stator inductor, a rotor inductor and an excitation inductor, and the leakage inductor comprises a stator leakage inductor and a rotor leakage inductor.
4. The method according to claim 1, wherein the method comprises the following steps: a method for converting a state space equation of a network side system into an extended harmonic domain by adopting a frequency domain constancy method specifically comprises the following steps:
adding a differential term of the state quantity on the left side of the original state space equation;
each state quantity and input quantity are decomposed into harmonic space vectors through bilateral Fourier, and the vectors contain Fourier coefficients of each harmonic; the method comprises the following steps that a time domain switching function of a network side converter is subjected to bilateral Fourier decomposition to obtain a switching function expressed in a Toeplitz matrix form in an extended harmonic domain;
the coefficient matrix of the original state space is adjusted correspondingly according to the dimension of the state quantity and the input quantity.
5. An output monitoring system for the wind power generation system output monitoring method based on the extended harmonic domain model according to any one of claims 1 to 4, comprising:
a time domain model building module: the system comprises a wind driven generator, a converter, a network side system and a direct current bus, wherein the network side system and the direct current bus are configured to establish a time domain model respectively aiming at the wind driven generator and the converter;
a data acquisition module: the system comprises a wind driven generator, a converter, a network side system and a direct current bus, wherein the system is configured to obtain electrical parameter data of the wind driven generator, the network side system of the converter and the direct current bus respectively;
an extended harmonic domain model building module: the system is configured to establish an extended harmonic domain model for the wind driven generator, a grid side system of the converter and the direct current bus respectively according to the obtained electrical parameter data through vector transformation and frequency domain normalization aiming at the established time domain model;
an integration monitoring module: the method comprises the steps that an extended harmonic domain model which is configured and used for being integrated and established is used, the end voltage of a motor stator is used as input, the output is the harmonic components of the motor stator current, the rotor current, the network side current and the direct current bus voltage in a converter, the integral extended harmonic domain dynamic model of the double-fed asynchronous wind driven generator is obtained, and the model is used for monitoring the output state of a wind power generation system.
6. An electronic device comprising a memory and a processor and computer instructions stored on the memory and executable on the processor, the computer instructions when executed by the processor performing the steps of the method of any of claims 1 to 4.
7. A computer-readable storage medium storing computer instructions which, when executed by a processor, perform the steps of the method of any one of claims 1 to 4.
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