Functional compound type multi-time-scale periodic fluctuation treatment system and method

Abstract

The invention discloses a function compound type multi-time scale periodic fluctuation treatment system and method, and relates to the field of new energy, the function compound type multi-time scale periodic fluctuation treatment system comprises a filter used for filtering electrical parameters of a target area to obtain a plurality of filtering components, the electrical parameters comprise voltage and current, and the multiple filtering components comprise a fundamental component, a harmonic component and an oscillation component; the controller is connected with the filter and used for processing the multiple filtering components to obtain multiple control signals, and the multiple control signals are in one-to-one correspondence with the multiple filtering components; the chain type converter is connected with the controller and used for converting the multiple control signals into multiple output electric energy, and the multiple output electric energy is used for conducting fluctuation treatment on the target area.

Description

Technical Field

[0001] The present application relates to the field of new energy, and more specifically, to a multi-functional multi-time-scale periodic fluctuation management system and method. Background Art

[0002] In the power system of offshore wind farms, with the continuous expansion of wind power generation and the widespread application of power electronic equipment, various fluctuation problems have become increasingly prominent, posing a severe challenge to the safe and stable operation of the power system. These fluctuation problems include not only the common harmonic problem, that is, the damage to the power quality of the power grid caused by the non-fundamental frequency current components generated by power electronic equipment, but also a series of oscillation phenomena, such as low-frequency oscillation, subsynchronous oscillation and supersynchronous oscillation. These oscillation problems often originate from the complex interaction between wind turbines, flexible DC transmission systems, dynamic reactive power compensation equipment and control systems.

[0003] Existing fluctuation control technologies usually target a single type of fluctuation problem. For example, static VAR generators (SVG) are mainly used for harmonic control, while oscillation suppression may rely on adjusting the control parameters of wind turbines or installing special damping control equipment. However, this decentralized control solution is not only inefficient, but also often difficult to take into account fluctuations in different frequency ranges in practical applications. In particular, when multiple fluctuations exist at the same time, a single technical means may not be able to effectively deal with it, thereby increasing the complexity and cost of the system.

[0004] In view of the related technologies, there are various fluctuation problems in wind farms, but the existing technologies lack a technical solution that can effectively deal with different types of fluctuation problems in wind farms, and no effective solution has been proposed yet.

[0005] Therefore, it is necessary to improve the related technology to overcome the above-mentioned defects in the related technology. Summary of the invention

[0006] The embodiments of the present application provide a multi-time-scale periodic fluctuation management system and method with complex functions, so as to at least solve the problem that in the related technology, there are multiple fluctuation problems in wind farms, but the prior art lacks a technical solution that can effectively manage different types of fluctuation problems in wind farms.

[0007] According to one aspect of an embodiment of the present application, a functionally complex multi-time-scale periodic fluctuation control system is provided, comprising: a filter, for filtering electrical parameters of a target area to obtain a plurality of filtering components, wherein the electrical parameters include voltage and current, and the plurality of filtering components include: a fundamental frequency component, a harmonic component, and an oscillation component; a controller, connected to the filter, for processing the plurality of filtering components to obtain a plurality of control signals, wherein the plurality of control signals correspond one-to-one to the plurality of filtering components; a chain converter, connected to the controller, for converting the plurality of control signals into a plurality of output electrical energies, wherein the plurality of output electrical energies are used for fluctuation control of the target area.

[0008] In an exemplary embodiment, the controller includes: a fundamental frequency control loop, which is used to process the fundamental frequency component to obtain a first control signal, wherein the first control signal is used to instruct the chain converter to output a fundamental frequency current corresponding to the fundamental frequency component, and the fundamental frequency current is used to maintain voltage stability in the target area; a harmonic control loop, which is used to process the harmonic component to obtain a second control signal, wherein the second control signal is used to instruct the chain converter to output a harmonic compensation current corresponding to the harmonic component, and the harmonic compensation current is used to perform harmonic control on the target area; an oscillation suppression control loop, which is used to process the oscillation component to obtain a third control signal, wherein the third control signal is used to instruct the chain converter to output a damping current corresponding to the oscillation component, and the damping current is used to suppress oscillation in the target area, and the multiple control signals include at least one of the following: the first control signal, the second control signal, and the third control signal, and the multiple output electric energy includes at least one of the following: the fundamental frequency current, the harmonic compensation current, and the damping current.

[0009] In an exemplary embodiment, control frequencies of the fundamental frequency control loop, the harmonic control loop, and the oscillation suppression control loop are all different.

[0010] In an exemplary embodiment, the baseband control loop is further used to: perform an error analysis on a reference voltage and an actual voltage measurement value to obtain a first error result, and perform an error analysis on a reference current and an actual current measurement value to obtain a second error result, wherein the baseband component includes the actual voltage measurement value and the actual current measurement value; and determine the first control signal based on the first error result and the second error result.

[0011] In an exemplary embodiment, the harmonic control loop is also used to: determine the harmonic current and harmonic voltage based on the harmonic components; perform harmonic current control on the harmonic current, and add virtual impedance to the first control result obtained to obtain a second control result; perform harmonic voltage control on the harmonic voltage to obtain a third control result; and determine the second control signal based on the second control result and the third control result.

[0012] In an exemplary embodiment, the oscillation suppression control loop is further used to: process the oscillation component through a damping controller to obtain the third control signal, wherein the magnitude of the damping current corresponding to the third control signal is proportional to the magnitude of the oscillation component.

[0013] According to another aspect of an embodiment of the present application, a functionally complex multi-time-scale periodic fluctuation control method is also provided, comprising: filtering the electrical parameters of the target area to obtain the multiple filtered components; processing the multiple filtered components to obtain the multiple control signals; and converting the multiple control signals into the multiple output electrical energies.

[0014] According to another aspect of the embodiment of the present application, a computer-readable storage medium is provided, in which a computer program is stored, wherein the computer program is configured to execute the above-mentioned functional composite multi-time-scale periodic fluctuation management method when running.

[0015] According to another aspect of an embodiment of the present application, there is also provided an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the functionally complex multi-time-scale periodic fluctuation management method through the computer program.

[0016] According to another aspect of the embodiments of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0017] Through the present application, the voltage and current of the target area are first filtered through a filter to obtain a variety of aluminum foil components, wherein the multiple filtering components include: fundamental frequency component, harmonic component, and oscillation component; then the multiple filtering components are processed by a controller connected to the filter to obtain a variety of control signals, wherein the multiple control signals correspond to the multiple filtering components one by one; finally, the multiple control signals are converted into a variety of output electric energies through a chain converter, so that the target area can be subjected to fluctuation management through the multiple output electric energies; the above-mentioned system integrates a variety of fluctuation management functions at the same time, can handle harmonic and oscillation problems at the same time, and provides dynamic compensation in a wide frequency range, which is of significant significance for improving the grid-connected capacity of wind farms and the stability of power systems; thereby solving the problem of multiple fluctuations in wind farms in related technologies and the lack of a technical solution that can effectively manage different types of fluctuations in wind farms in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 It is a hardware structure block diagram of a computer terminal of a multi-time scale periodic fluctuation management method with a functionally complex embodiment of the present application;

[0021] Figure 2 It is a structural block diagram of a multi-time-scale periodic fluctuation management system with complex functions according to an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of the structure of a controller according to an embodiment of the present application;

[0023] Figure 4 This is a schematic diagram of an application scenario of a multi-time-scale periodic fluctuation management system with a complex function according to an embodiment of the present application;

[0024] Figure 5 It is a flow chart of a functionally complex multi-time-scale periodic fluctuation management method according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] The method embodiments provided in the embodiments of the present application can be executed in a computer terminal or a similar computing device. Taking running on a computer terminal as an example, Figure 1 This is a hardware structure block diagram of a computer terminal of a multi-time scale periodic fluctuation management method with a functionally complex embodiment of the present application. Figure 1 As shown, the computer terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor (Central Processing Unit, CPU) or a programmable logic device (Field Programmable Gate Array, FPGA)) and a memory 104 for storing data, wherein the above-mentioned computer terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above-mentioned computer terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0028] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the functionally complex multi-time scale periodic fluctuation management method in the embodiment of the present application. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0029] A wireless network provided by a communication provider of a computer terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0030] In the relevant technologies, wind farms face a variety of fluctuation problems during operation. The following introduces several major fluctuation problems and their corresponding solutions:

[0031] (1) Oscillation risk:

[0032] In the course of large-scale new energy development, as the degree of power electronics in the power system continues to deepen, the problem of wide-band oscillation in areas where new energy is concentrated has become increasingly prominent. For example, subsynchronous oscillations between a doubly-fed wind farm and a transmission system with series compensation have occurred many times in a certain area, with an oscillation frequency of about 6-8Hz and an amplitude of up to about 50%, causing a large number of wind turbines to be disconnected from the grid. Studies have shown that compared with traditional equipment such as generators, power electronic equipment has significant differences in physical structure, control mode, dynamic response, and interaction with other equipment. The fast and flexible control characteristics of power electronic equipment have a profound impact on the dynamic behavior of the power system, thereby causing oscillation problems in the power system over a wide frequency range.

[0033] Offshore wind power grid-connected systems, similar to the development of new energy on land, also face significant oscillation risks. There are a large number of power electronic equipment in offshore wind farms, including wind turbines, dynamic reactive power compensation and flexible DC transmission systems, which are sensitive to system voltage changes and will respond quickly to system changes and disturbances. The interaction between wind power converters, MMC flexible DC converters, FACTS devices, wiring cables and control systems causes multiple non-fundamental frequency energy exchange processes between power electronic equipment. In areas where offshore wind power is developed on a large scale, the risk of oscillations caused by multiple wind farms is higher. For example, offshore wind power grid-connected projects using flexible DC transmission technology have reported oscillation events in multiple commissioning or operation stages at home and abroad. These events include subsynchronous oscillations and medium and high frequency oscillations. As a highly power-electronic system, the types, mechanisms and influencing factors of high-frequency oscillations in offshore wind power systems are closely related to the power electronic equipment inside them. In the AC transmission and flexible DC transmission configurations of offshore wind power, the types of broadband oscillations that the system may experience include low-frequency oscillations (frequency range 0.5Hz to 2Hz), subsynchronous / supersynchronous oscillations (frequency range 2Hz to 100Hz) and high-frequency resonances (frequency range 200Hz to 5000Hz). High-frequency resonances mainly occur inside the flexible DC system and manifest as electromagnetic oscillations. The interactions between the mechanical components of the offshore wind power system, wind turbine converters, MMC flexible DC converters, flexible AC transmission systems (FACTS) devices, wiring cables and control systems are mainly manifested as low-frequency oscillations and subsynchronous / supersynchronous oscillations.

[0034] In order to suppress the oscillation caused by the grid connection of wind farms, two major control strategies are currently used; one is based on the suppression measures of the wind turbine itself. The suppression strategy starting from the power generation unit itself includes the optimization of the generator controller parameters and the additional damping controller of the converter control loop. The second is to rely on auxiliary equipment with additional damping control. By connecting damping control equipment in series and parallel in the system, the sub- / super-synchronous oscillation signal in the system is responded to and controlled to increase the grid connection stability of the system in the sub- / super-synchronous frequency band. For example, an SVG device with additional control is connected in parallel at the outlet of the wind farm, and a controllable series compensation TCSC device is connected in the line. Static VAR generator (SVG), also known as STATCOM, is a device that uses a high-power inverter to achieve dynamic reactive compensation. SVG monitors the signal containing the torsional vibration frequency of the generator shaft system and uses it as the input of the controller to accurately control the sub-synchronous component in its output voltage. In this way, SVG can adjust the current injected into the power system, thereby generating a damping torque on the generator rotor and effectively suppressing sub-synchronous oscillations. The application of SVG in the transmission network not only enhances the stability of the power system, but also improves the damping capacity of the system, helps to suppress various oscillation phenomena, and significantly enhances the voltage transmission efficiency.

[0035] (2) Harmonic problem:

[0036] Since the collection network of large offshore wind farms uses cable lines to collect electric energy, the phase-to-phase capacitance and ground capacitance of the cables cannot be ignored. The impedance network of the collection network is complex and changeable, and there is a risk of high-frequency resonance caused by interaction with the impedance of wind turbines, threatening the safe and stable operation of wind farms. The harmonic currents generated by wind turbines are collected on the integrated lines and then penetrate into the system. The inherent spectrum characteristics of the collection lines will produce series / parallel resonance phenomena for specific harmonics, further amplifying the harmonic voltage / harmonic current, resulting in excessive harmonic voltage / harmonic current content. In addition, the source of harmonic voltage sources in the power system, such as the background harmonics of the power system, will cause the harmonic voltage / harmonic current at the common bus to be amplified or even exceeded due to the interaction between the harmonic impedance of the power system and the impedance of the wind turbine converter and the impedance of the collection line.

[0037] By using modern power electronics technology and digital signal processing technology based on high-speed DSP devices, a new type of active power filter, a special device for power harmonic control, is manufactured. The active power filter obtains the harmonic components in the system through detection, generates a compensation current with the same amplitude and opposite polarity as the harmonic current of the power grid, and injects it into the power grid to compensate or offset the harmonic current. This is an effective means of harmonic control.

[0038] Existing fluctuation control technologies usually only target a single type of fluctuation problem. For example, static VAR generators (SVG) are mainly used for harmonic control, while oscillation suppression may rely on adjusting the control parameters of wind turbines or installing special damping control equipment. However, this decentralized control solution is not only inefficient, but also often difficult to take into account fluctuations in different frequency ranges in practical applications. In particular, when multiple fluctuations exist at the same time, a single technical means may not be able to effectively deal with it, thereby increasing the complexity and cost of the system.

[0039] In view of the above problems, a multi-time scale periodic fluctuation management system with complex functions is provided in this embodiment. Figure 2 is a structural block diagram of a multi-time scale periodic fluctuation management system with a functionally complex structure according to an embodiment of the present application, such as Figure 2 As shown, including:

[0040] A filter 22, used for filtering the electrical parameters of the target area to obtain a plurality of filtering components, wherein the electrical parameters include voltage and current, and the plurality of filtering components include: a fundamental frequency component, a harmonic component, and an oscillation component;

[0041] A controller 24, connected to the filter 22, for processing the multiple filtering components to obtain multiple control signals, wherein the multiple control signals correspond to the multiple filtering components one by one;

[0042] The chain converter 26 is connected to the controller 24 and is used to convert the multiple control signals into multiple output electric energies, wherein the multiple output electric energies are used to perform fluctuation management on the target area.

[0043] Through the above steps, the voltage and current of the target area are first filtered through a filter to obtain a variety of aluminum foil components, wherein the multiple filtering components include: fundamental frequency component, harmonic component, oscillation component; then the multiple filtering components are processed by a controller connected to the filter to obtain a variety of control signals, wherein the multiple control signals correspond to the multiple filtering components one by one; finally, the multiple control signals are converted into a variety of output electric energies through a chain converter, so that the target area can be subjected to fluctuation management through the multiple output electric energies; the above system is adopted, and multiple fluctuation management functions are integrated at the same time, which can simultaneously handle harmonic and oscillation problems and provide dynamic compensation in a wide frequency range, which is of significant significance for improving the grid-connected capacity of wind farms and the stability of power systems; thereby solving the problem that there are multiple fluctuations in wind farms in related technologies, and the existing technology lacks a technical solution that can effectively manage different types of fluctuations in wind farms.

[0044] In an exemplary embodiment, the controller 24 includes: a fundamental frequency control loop, which is used to process the fundamental frequency component to obtain a first control signal, wherein the first control signal is used to instruct the chain converter to output a fundamental frequency current corresponding to the fundamental frequency component, and the fundamental frequency current is used to maintain voltage stability in the target area; a harmonic control loop, which is used to process the harmonic component to obtain a second control signal, wherein the second control signal is used to instruct the chain converter to output a harmonic compensation current corresponding to the harmonic component, and the harmonic compensation current is used to perform harmonic control on the target area; an oscillation suppression control loop, which is used to process the oscillation component to obtain a third control signal, wherein the third control signal is used to instruct the chain converter to output a damping current corresponding to the oscillation component, and the damping current is used to suppress oscillation in the target area, and the multiple control signals include at least one of the following: the first control signal, the second control signal, and the third control signal, and the multiple output electrical energies include at least one of the following: the fundamental frequency current, the harmonic compensation current, and the damping current.

[0045] The schematic diagram of the controller is as follows: Figure 3As shown in the figure, the controller is composed of three control loops: base frequency control loop, harmonic control loop, and oscillation suppression control loop. The base frequency control loop outputs a smaller "fundamental frequency" current to maintain the stability of the device terminal voltage; the harmonic control loop realizes the comprehensive control of harmonic voltage and harmonic current, and is used to output harmonic compensation current with the same frequency as the "harmonic frequency"; the oscillation suppression control loop is used to output a damping current with the same "oscillation frequency".

[0046] Optionally, the control frequencies of the base frequency control loop, the harmonic control loop and the oscillation suppression control loop are all different.

[0047] The control frequency of the base frequency control loop is 50Hz, the control frequency of the oscillation suppression control loop is set to 1-150Hz (the oscillation frequency range for AC access of offshore wind power), and the control frequency of the harmonic control loop is set to 250Hz and 350Hz (5th / 7th harmonics, which can be changed according to the actual engineering harmonic frequency). By setting different frequencies, the mutual coupling effects between control loops can be minimized.

[0048] Optionally, the baseband control loop is also used to: perform error analysis on a reference voltage and an actual voltage measurement value to obtain a first error result, and perform error analysis on a reference current and an actual current measurement value to obtain a second error result, wherein the baseband component includes the actual voltage measurement value and the actual current measurement value; and determine the first control signal based on the first error result and the second error result.

[0049] like Figure 3 As shown, the baseband control loop includes a voltage outer loop and a current inner loop. The voltage outer loop is used to perform error analysis on the reference voltage loop and the actual voltage measurement value to obtain a first error result, while the current inner loop is used to perform error analysis on the reference current and the actual current measurement value to obtain a second error result. Finally, the baseband control loop determines the first control signal in combination with the first error result and the second error result.

[0050] It should be noted that the base frequency control loop in SVG (static var generator) or similar power electronic equipment is mainly used to maintain the voltage stability of the power system, ensure that the device port voltage is synchronized with the grid voltage, and provide or absorb reactive power when needed. The input and output of the base frequency control loop can be specifically described as follows: Input:

[0051] Reference voltage (U_{ref}): This is a voltage value based on system requirements or settings, used as a control target to ensure that the SVG port voltage is close to or equal to this target value.

[0052] Actual voltage measurement value ((U_{abc})): The real-time three-phase AC voltage value of the SVG grid connection point collected by the voltage transformer (PT), which is used to compare with the reference voltage to form a control error signal.

[0053] Reference current (I_{ref}): This is the current value set based on the control target of the SVG (such as providing or absorbing a specific reactive power), usually the current level that needs to be maintained at the base frequency.

[0054] Actual current measurement value (I_{abc}): The real-time three-phase AC current value of the SVG grid connection point collected by the current transformer (CT), which is used to compare with the reference current to form a control error signal.

[0055] Output:

[0056] Control signal ((i_m)): The control signal output of the baseband control loop is usually a current command corresponding to the amount of reactive power that the SVG needs to output or absorb. This signal will be sent to the current control loop of the SVG to instruct the SVG how to adjust the output of its inverter to achieve reactive power regulation.

[0057] Adjusted DC side voltage (U_{dc}): Through the adjustment of the base frequency control loop, the DC side voltage of the SVG may be appropriately adjusted according to system requirements to ensure that the inverter has enough energy to meet the reactive power regulation requirements.

[0058] The core task of the baseband control loop is to ensure that the SVG can stably operate in the power system according to the predetermined reference voltage and current requirements, provide or absorb reactive power, and maintain system voltage stability. In the application embodiment, the output signal of the baseband control loop will be superimposed with the output signals of the harmonic control loop and the oscillation suppression control loop, and act together on the inverter control of the SVG to achieve the control of multi-time scale periodic fluctuations.

[0059] It should be noted that reactive power is an important concept in the power system. It and active power together constitute the total power in the power system. In the AC power system, reactive power (usually represented by Q) refers to the electrical energy stored and exchanged in inductive and capacitive components instead of being converted into useful working energy. Reactive power constantly travels back and forth between the power source and the load in the circuit. It does not directly do work, but it has an important impact on the voltage stability and power transmission efficiency of the power system.

[0060] For example, when the current lags behind the voltage in an inductive load (such as a motor and a transformer), inductive reactive power appears in the system; conversely, when the current leads the voltage, such as in a capacitive load (such as a capacitor and some power electronic equipment), capacitive reactive power appears in the system. The balance of reactive power is essential to maintaining the voltage level of the power system and improving the power transmission capacity. If there is insufficient reactive power in the power system, it may cause the voltage level to drop and affect the normal operation of the power equipment; while excess reactive power may cause the voltage level to rise abnormally, which also poses a threat to the power system.

[0061] Reactive power compensation equipment, such as SVG (static VAR generator) and SVC (static VAR compensator), helps the power system maintain voltage stability and optimize power transmission efficiency by providing or absorbing reactive power. It is an indispensable part of modern power systems.

[0062] In summary, the base frequency control loop first receives the system reference voltage and actual voltage measurement, as well as the reference current and actual current measurement, to evaluate the voltage and current status of the SVG grid connection point. By comparing these input values, the loop calculates the control error and generates appropriate control signals to guide the SVG to adjust its output current to stabilize the voltage and harmonics at the grid connection point. Ultimately, the control signal output by the base frequency control loop ensures that the SVG can accurately provide or absorb reactive power and maintain stable operation within the base frequency range of the power system.

[0063] Optionally, the harmonic control loop is also used to: determine harmonic current and harmonic voltage based on the harmonic components; perform harmonic current control on the harmonic current, and add virtual impedance to the first control result obtained to obtain a second control result; perform harmonic voltage control on the harmonic voltage to obtain a third control result; and determine the second control signal based on the second control result and the third control result.

[0064] The working process of the harmonic control loop is as follows: First, the loop detects and analyzes the harmonic components in the power system, and captures the harmonic voltage and current signals in the system through the current transformer (CT) and the voltage transformer (PT). Secondly, the loop calculates the compensation current instruction with the same amplitude as the detected harmonic component but opposite polarity, in order to offset or weaken the harmonics in the power system and improve the power quality. Finally, the generated compensation current instruction is sent to the current control loop of the SVG to guide the SVG to accurately generate harmonic compensation current and inject it into the power grid to achieve harmonic control.

[0065] Optionally, the oscillation suppression control loop is further used to: process the oscillation component through a damping controller to obtain the third control signal, wherein the magnitude of the damping current corresponding to the third control signal is proportional to the magnitude of the oscillation component.

[0066] The working process of the oscillation suppression control loop is as follows: the control loop monitors the voltage and current signals in the system and identifies the oscillation components, especially those periodic fluctuations that may cause system instability. Subsequently, the loop designs and applies a damping controller to generate an oscillation frequency current command proportional to the system voltage oscillation component, increase system damping, and suppress oscillation. These command currents are superimposed with the fundamental frequency and harmonic control signals and executed by the main circuit of the SVG. By injecting appropriate current into the power grid, the oscillation in the system is effectively damped, improving the stability and reliability of the power system.

[0067] Through the superposition of the above-mentioned multiple control signals, the system can simultaneously realize the functions of harmonic control and oscillation suppression: when controlling harmonics, the device obtains the harmonic components in the system through detection and filtering, and generates a compensation current with the same amplitude and opposite polarity as the harmonic current of the power grid and injects it into the power grid to compensate or offset the harmonic current; when suppressing oscillation, the device obtains the oscillation components in the system through monitoring and filtering, and reasonably designs the damping controller (i.e. Figure 3 The oscillation controller in the converter generates an oscillation frequency current proportional to the system voltage oscillation component and injects it into the system, thereby damping the oscillation of the wind farm.

[0068] The application scenarios of the above-mentioned multi-time scale periodic fluctuation management system with complex functions are as follows: Figure 4 As shown in the figure, the system adopts a main circuit topology similar to that of the parallel SVG, and the converter is connected to the offshore wind farm metering station through a 220kV dedicated step-down transformer.

[0069] Based on this application scenario, the signal path of the system during operation is as follows: Install a voltage transformer PT and a current transformer CT at the offshore wind farm metering station to measure the voltage v at the metering station. c With current i L ; By setting an appropriate filter, the voltage v is extracted c With current i L The fundamental frequency component u abc 、i abc , harmonic component u h 、i h And the oscillation component u s , respectively input into the corresponding controller; each controller respectively outputs the control signal of the corresponding control function, and the superimposed signal is connected to the booster station through the chain converter and the coupling transformer to realize the control of multi-time scale periodic fluctuations of the offshore wind farm.

[0070] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0071] Figure 5 It is a flow chart of a method for managing multi-time-scale periodic fluctuations with a functional composite type according to an embodiment of the present application. The method is applied to the above-mentioned multi-time-scale periodic fluctuation management system with a functional composite type. The method includes the following steps S502-S506:

[0072] Step S502, filtering the electrical parameters of the target area to obtain the multiple filtering components;

[0073] Step S504, processing the multiple filtering components to obtain the multiple control signals;

[0074] Step S506, converting the multiple control signals into the multiple output electrical energies.

[0075] Through the above scheme, the electrical parameters of the target area are first filtered to obtain a variety of filter components; then these multiple filter components are processed to obtain a variety of control signals, and finally these multiple control signals are converted into a variety of output electric energies to complete the fluctuation management of the target area; using the above scheme, a variety of fluctuation management functions are integrated into the system at the same time, which can handle harmonic and oscillation problems at the same time and provide dynamic compensation within a wide frequency range, which is of significant significance for improving the grid-connected capacity of wind farms and the stability of power systems; thereby solving the problem of multiple fluctuations in wind farms in related technologies and the lack of a technical solution that can effectively manage different types of fluctuations in wind farms in the prior art.

[0076] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0077] Optionally, in this embodiment, the storage medium may be configured to store a computer program for performing the following steps:

[0078] S1, filtering the electrical parameters of the target area to obtain the multiple filtering components;

[0079] S2, processing the multiple filtering components to obtain the multiple control signals;

[0080] S3, converting the plurality of control signals into the plurality of output electrical energies.

[0081] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0082] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0083] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0084] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0085] S1, filtering the electrical parameters of the target area to obtain the multiple filtering components;

[0086] S2, processing the multiple filtering components to obtain the multiple control signals;

[0087] S3, converting the plurality of control signals into the plurality of output electrical energies.

[0088] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0089] An embodiment of the present application further provides a computer program product, comprising a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program product, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0090] Optionally, in this embodiment, the above computer program may be configured to implement the following steps when executed by a processor:

[0091] S1, filtering the electrical parameters of the target area to obtain the multiple filtering components;

[0092] S2, processing the multiple filtering components to obtain the multiple control signals;

[0093] S3, converting the plurality of control signals into the plurality of output electrical energies.

[0094] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0095] Obviously, those skilled in the art should understand that the above modules or steps of the present application can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that herein, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0096] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A multi-time scale periodic fluctuation management system with complex functions, characterized by: include: A filter, used for filtering the electrical parameters of the target area to obtain a plurality of filter components, wherein the electrical parameters include voltage and current, and the plurality of filter components include: a fundamental frequency component, a harmonic component, and an oscillation component; A controller connected to the filter, and configured to process the plurality of filter components to obtain a plurality of control signals, wherein the plurality of control signals correspond to the plurality of filter components one by one; A chain converter is connected to the controller and is used to convert the multiple control signals into multiple output electrical energies, wherein the multiple output electrical energies are used to perform fluctuation management on the target area.

2. The system according to claim 1, characterized in that The controller comprises: A fundamental frequency control loop, used for processing the fundamental frequency component to obtain a first control signal, wherein the first control signal is used to instruct the chain converter to output a fundamental frequency current corresponding to the fundamental frequency component, and the fundamental frequency current is used to maintain voltage stability in the target area; A harmonic control loop, used for processing the harmonic component to obtain a second control signal, wherein the second control signal is used to instruct the chain converter to output a harmonic compensation current corresponding to the harmonic component, and the harmonic compensation current is used to perform harmonic control on the target area; An oscillation suppression control loop is used to process the oscillation component to obtain a third control signal, wherein the third control signal is used to instruct the chain converter to output a damping current corresponding to the oscillation component, and the damping current is used to suppress oscillation in the target area. The multiple control signals include at least one of the following: the first control signal, the second control signal, and the third control signal. The multiple output electrical energies include at least one of the following: the fundamental frequency current, the harmonic compensation current, and the damping current.

3. The system according to claim 2, characterized in that The control frequencies of the base frequency control loop, the harmonic control loop and the oscillation suppression control loop are all different.

4. The system according to claim 2, characterized in that The base frequency control loop is also used for: Performing an error analysis on a reference voltage and an actual voltage measurement value to obtain a first error result, and performing an error analysis on a reference current and an actual current measurement value to obtain a second error result, wherein the fundamental frequency component includes the actual voltage measurement value and the actual current measurement value; The first control signal is determined according to the first error result and the second error result.

5. The system according to claim 2, characterized in that The harmonic control circuit is further used to: determine the harmonic current and harmonic voltage according to the harmonic components; Performing harmonic current control on the harmonic current, and adding virtual impedance to the obtained first control result to obtain a second control result; performing a harmonic voltage control device on the harmonic voltage to obtain a third control result; The second control signal is determined according to the second control result and the third control result.

6. The system according to claim 2, characterized in that The oscillation suppression control loop is further used to: process the oscillation component through a damping controller to obtain the third control signal, wherein the magnitude of the damping current corresponding to the third control signal is proportional to the magnitude of the oscillation component.

7. A multi-time scale periodic fluctuation management method with complex functions, characterized in that: The system applied to any one of claims 1 to 6, comprising: filtering the electrical parameters of the target area to obtain the plurality of filtering components; Processing the multiple filtering components to obtain the multiple control signals; The plurality of control signals are converted into the plurality of output electrical energies.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method of claim 7 when executed.

9. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method of claim 7 through the computer program.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to claim 7 are implemented.

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