Power decoupling method with voltage feed-forward compensation and adaptive virtual impedance cooperative control

Abstract

The application relates to the technical field of new energy power system control, and relates to a power decoupling method of voltage feedforward compensation and adaptive virtual impedance cooperative control. The method comprises the following steps: acquiring grid current and grid voltage, and calculating a real measured value of reactive power and a real measured value of active power of the grid; performing virtual synchronous machine control, introducing a voltage feedforward pre-compensation term in a reactive control loop; calculating a VSG-compensated reactive control loop, acquiring a VSG output side voltage and an instantaneous angular frequency; adopting adaptive virtual impedance control, calculating an adaptive virtual impedance reference value, dynamically adjusting a line impedance, calculating an input instruction voltage of a voltage loop according to the line impedance; and adjusting the output performance of an inverter according to the instruction voltage. The application effectively solves the power fluctuation problem caused by the amplitude variation of the VSG output voltage, and weakens the dynamic influence of the power coupling term.

Description

Technical Field

[0001] This application relates to the field of new energy power system control technology, and to a power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control. Background Technology

[0002] Currently, power systems are gradually shifting towards those with a high proportion of renewable energy. Virtual Synchronous Generator (VSG) control, as a typical grid-connected renewable energy control method, simulates the oscillation equations and speed regulation / excitation mechanisms of a synchronous machine at the control layer. This provides the grid with inertia and damping support similar to a synchronous machine, enabling distributed generation to provide good frequency and voltage support and regulation, thus becoming an important control method for renewable energy participation in high-penetration grid construction. However, the ideal "active power-phase angle, reactive power-voltage" decoupling does not strictly hold true in resistive-inductive lines. The coupling effect is even more pronounced when line resistance is not negligible or the power angle is large. Therefore, decoupling control of grid-connected renewable energy power has become a hot topic in the field of renewable energy control.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0005] This disclosure provides a power decoupling method that combines voltage feedforward compensation and adaptive virtual impedance coordinated control. Based on the traditional grid-type VSG control architecture, a feedforward voltage pre-compensation term is added to the original reactive power control loop. The adaptive virtual impedance control adjustment method is used according to the current amplitude and frequency deviation of the line to effectively reduce the power fluctuation problem caused by the VSG output voltage amplitude variation, thereby offsetting the dynamic influence of the power coupling term.

[0006] In some embodiments, the method includes:

[0007] Obtain the grid current and grid voltage, and calculate the measured values ​​of the grid's reactive power and active power;

[0008] Virtual synchronous machine control is performed based on the measured values ​​of reactive power, active power, reactive power reference value, and active power reference value. A voltage feedforward pre-compensation term is introduced into the reactive power control loop to dynamically compensate for voltage deviation caused by changes in power angle based on changes in active power.

[0009] Calculate the reactive power control loop after VSG compensation based on the voltage feedforward pre-compensation term, and obtain the VSG output side voltage and instantaneous angular frequency based on the VSG active power control loop and reactive power control loop.

[0010] Adaptive virtual impedance control is adopted, the adaptive virtual impedance reference value is calculated, and the line impedance is dynamically adjusted based on the adaptive virtual impedance reference value, VSG output voltage and instantaneous angular frequency. The voltage loop input command voltage is calculated based on the line impedance.

[0011] The command voltage is input to the voltage and current dual-loop control to generate SVPWM control commands, which are then used to adjust the inverter output performance.

[0012] Preferably, the compensation voltage difference of the voltage feedforward pre-compensation term The calculation formula is:

[0013] ,

[0014] in, The compensated VSG reference voltage command value. For the VSG output side voltage, This is the grid-side voltage. The power factor angle, The impedance angle of the line. This is the system power angle.

[0015] Preferably, the system power angle is as follows:

[0016] ,

[0017] in, The instantaneous angular frequency, This is the rated angular frequency;

[0018] The power factor angle is as follows:

[0019] ,

[0020] in, This is a reference value for reactive power. This is a reference value for active power.

[0021] Preferably, the compensated reactive power control loop calculated based on the voltage feedforward pre-compensation term is as follows:

[0022] ,

[0023] in, The reactive inertia coefficient of VSG. This is a reference value for reactive power. This is the measured value of reactive power. The reactive power droop factor of VSG. This is the VSG reference voltage command value.

[0024] Preferably, the virtual impedance tuning formula in the adaptive virtual impedance control is as follows:

[0025] ,

[0026] ,

[0027] ,

[0028] ,

[0029]

[0030] in, For virtual resistance, For virtual inductance, This is the steady-state value of the virtual inductance. This is the steady-state value of the virtual resistance. For dynamic virtual resistance, This represents the virtual reactance steady-state value. This represents the virtual reactance steady-state value. This is the steady-state value of the virtual resistance. For dynamic virtual inductance, This is the virtual impedance angle. This is the change in virtual impedance angle. For virtual impedance, This is the virtual impedance change. This represents the change in virtual reactance. The instantaneous angular frequency, The total equivalent impedance is... This is the grid-side voltage. It is the equivalent impedance angle. This represents the change in active power. This is the measured value of reactive power. This is the system power angle.

[0031] Preferably, the voltage loop input command voltage is calculated as follows:

[0032] ,

[0033] in, For voltage loop Shaft reference voltage, for Shaft VSG output current, for Shaft VSG output current, For voltage loop Shaft reference voltage.

[0034] Preferably, the active power control loop formula is as follows:

[0035] ,

[0036] in, For rotational inertia, The droop control frequency modulation coefficient. This is the active power output value. is the damping coefficient.

[0037] Preferably, the voltage and current dual-loop control has the same structure as the grid-type control dual-loop control, and the inverter output performance is adjusted through the hierarchical coordination of the outer voltage loop and the inner current loop.

[0038] In some embodiments, the apparatus includes a processor and a memory storing program instructions, the processor being configured to execute the power decoupling method of voltage feedforward compensation and adaptive virtual impedance co-control when the program instructions are executed.

[0039] In some embodiments, the storage medium stores program instructions that, when executed, perform the power decoupling method of voltage feedforward compensation and adaptive virtual impedance coordinated control.

[0040] The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control provided in this disclosure can achieve the following technical effects:

[0041] This invention introduces voltage feedforward pre-compensation in the power loop to reduce voltage deviation. The compensation is directly applied to the controller input, while adaptive virtual impedance control eliminates the influence of line impedance on power coupling, effectively offsetting the voltage vector offset caused by line impedance. Through the combined action of feedforward voltage compensation and virtual impedance control, precise decoupling of active and reactive power is achieved. The compensated control significantly reduces reactive power fluctuations, avoiding the oscillations caused by the mutual constraint between active and reactive power in traditional methods, resulting in a more stable dynamic response of the system.

[0042] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0043] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0044] Figure 1 Block diagram of the control strategy for a network-type VSG;

[0045] Figure 2 This is a schematic diagram of the method flow of the present invention;

[0046] Figure 3 Schematic diagram of VSG feedforward voltage pre-compensation;

[0047] Figure 4 Decoupling power response curves using traditional methods;

[0048] Figure 5 Decoupling power response curves for the new method;

[0049] Figure 6 This is a schematic diagram of the device structure provided by the present invention.

[0050] In the picture: The DC side voltage is, Grid voltage; This is the output voltage of the filter capacitor. This refers to the inverter output current. For grid current, This refers to the inverter output voltage. , and These include the filter inductor, filter capacitor, and inductor parasitic resistance. and They are respectively of shaft and Axial components; and They are respectively of shaft and Axial components; and They are respectively of shaft and Axis component, SVPWM is space vector pulse width modulation. This is a reference value for active power. This is a reference value for reactive power. This refers to the VSG output voltage value. Let be the instantaneous angular frequency of the system. For voltage loop Shaft reference voltage, For voltage loop Shaft reference voltage, The damping coefficient is... The system's rated angular frequency, For rotational inertia, The droop control frequency modulation coefficient. This is the active power output value. For rotational inertia, The power factor angle, This is the VSG reference voltage command value. To compensate for the voltage difference, This is a reference value for reactive power. This is the measured value of reactive power. The reactive inertia coefficient, For virtual resistance, For virtual inductance, This is the grid voltage. For the system power angle, It is the equivalent impedance angle. For impedance voltage drop, Compensated VSG line impedance voltage drop. This is the grid-connected current. Detailed Implementation

[0051] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0052] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0053] Example 1

[0054] like Figures 1-3As shown, a power decoupling method combining voltage feedforward compensation and adaptive virtual impedance coordinated control employs dual regulation through voltage pre-compensation and adaptive virtual impedance. First, a voltage feedforward pre-compensation stage is introduced into the reactive power control loop to dynamically pre-compensate for voltage fluctuations caused by changes in the power angle during active power changes, thereby reducing the impact on reactive power dynamics. Then, adaptive virtual impedance control is introduced to decouple reactive and active power caused by non-inductive line transmission power, ultimately achieving precise active-reactive power decoupling.

[0055] Specifically, including:

[0056] S1: Obtain the grid current and grid voltage, and calculate the measured values ​​of reactive power and active power of the grid.

[0057] S2: Based on the measured values ​​of reactive power, active power, reactive power reference value, and active power reference value, a virtual synchronous machine control is performed. A voltage feedforward pre-compensation term is introduced into the reactive power control loop to dynamically compensate for voltage deviations caused by changes in the power angle based on changes in active power.

[0058] S3: Calculate the reactive power control loop after VSG compensation based on the voltage feedforward pre-compensation term, and obtain the VSG output side voltage and instantaneous angular frequency based on the VSG active power control loop and reactive power control loop.

[0059] S4: Adaptive virtual impedance control is adopted. The adaptive virtual impedance reference value is calculated. The line impedance is dynamically adjusted based on the adaptive virtual impedance reference value, the VSG output voltage and the instantaneous angular frequency. The voltage loop input command voltage is calculated based on the line impedance.

[0060] S5: Input the command voltage to the voltage and current dual-loop control to generate SVPWM control command, and adjust the inverter output performance through SVPWM.

[0061] As a refinement of the above embodiments, the compensation voltage difference of the voltage feedforward pre-compensation term... The calculation formula is:

[0062] ,

[0063] in, The compensated VSG reference voltage command value. For the VSG output side voltage, This is the grid-side voltage. The power factor angle, The impedance angle of the line. This is the system power angle.

[0064] The specific acquisition process is as follows:

[0065] The voltage regulation capability of a traditional VSG is achieved through reactive power control loop control, as shown in the following formula:

[0066] ,

[0067] in, and These are the VSG reactive inertia coefficient and reactive droop coefficient, respectively, which simulate the voltage regulation characteristics and droop characteristics of a synchronous generator. This is a reference value for reactive power. This is the measured value of reactive power. This is the VSG reference voltage command value. This refers to the output voltage value of the VSG.

[0068] Reactive power is adjusted To achieve control, reactive power is indeed closely related to the power angle. However, since the power angle corresponds to active power, when the active power reference value... When the angle of work changes, the resulting angle of work Changes will affect reactive power through coupling terms. Fluctuations occur. Therefore, reactive power loop voltage feedforward pre-compensation is used to reduce the dynamic impact of active power changes on reactive power generation. The specific compensation method is as follows:

[0069] (1) System power angle The calculation formula is:

[0070] (1)

[0071] in, and These are the instantaneous angular frequency and the rated angular frequency of the system, respectively.

[0072] (2) The voltage drop across the line impedance is:

[0073] (2)

[0074] ,

[0075] ,

[0076]

[0077] in, The impedance angle of the line. This is the grid voltage. This is the line impedance resistance value. This represents the line impedance and inductance value. For line inductance, The inherent impedance of the line. Imaginary unit.

[0078] (3) To facilitate power calculation, the line impedance is assumed to be purely inductive, and regulation is achieved through an adaptive virtual impedance circuit. Power loss due to line impedance is ignored, and power is calculated from the grid side, with the active power referenced... With reactive power reference The power factor angle between Grid voltage With impedance voltage drop The ideal angle difference between them is Let the compensated VSG reference voltage command value and the line impedance voltage drop be respectively... and .

[0079] According to the relationship between sides and angles,

[0080] (3)

[0081] The voltage difference that needs to be compensated is:

[0082] (4)

[0083] Among them, the power factor angle .

[0084] (4) Substituting the voltage to be compensated into the reactive power control loop yields:

[0085] (5)

[0086] Feedforward voltage pre-compensation can offset the impact of active power changes on reactive power, thereby improving the dynamic performance of reactive power and avoiding the impact of reactive power fluctuations on the system.

[0087] As a refinement of the above embodiments, the virtual impedance tuning formula in the adaptive virtual impedance control is as follows:

[0088] ,

[0089] ,

[0090] ,

[0091] ,

[0092]

[0093] in, For virtual resistance, For virtual inductance, This is the steady-state value of the virtual inductance. This is the steady-state value of the virtual resistance. For dynamic virtual resistance, This represents the virtual reactance steady-state value. This represents the virtual reactance steady-state value. This is the steady-state value of the virtual resistance. For dynamic virtual inductance, This is the virtual impedance angle. This is the change in virtual impedance angle. For virtual impedance, This is the virtual impedance change. This represents the change in virtual reactance. The instantaneous angular frequency, The total equivalent impedance is... This is the grid-side voltage. It is the equivalent impedance angle. This represents the change in active power. This is the measured value of reactive power. This is the system power angle.

[0094] Specifically, the acquisition process is as follows:

[0095] To meet the requirement of the reactive voltage pre-compensation stage for the line to be purely inductive, virtual impedance control is used to dynamically adjust the line impedance value, making the line impedance equivalent to approximately inductive, thereby further reducing the power coupling caused by line variations; the specific principle is as follows:

[0096] Synchronous rotation of the three-phase grid-connected inverter In the coordinate system, the lines can be equivalent to a series connection. Impedance network. The inverter adds a virtual impedance voltage to the voltage loop as follows:

[0097] (7)

[0098] in, for Shaft virtual impedance voltage, for Shaft virtual impedance voltage; for Shaft VSG output current, for Shaft VSG output current.

[0099] The "equivalent series" effect is achieved by subtracting the voltage commands. In the voltage-current dual-loop control, the voltage loop input command voltage is:

[0100] (8)

[0101] in, and These are dynamic virtual resistance and inductance, respectively. For voltage loop Shaft reference voltage, For voltage loop Shaft reference voltage.

[0102] To obtain the desired grid-connected equivalent impedance, the actual line parameters are superimposed in series with an adjustable virtual impedance. Total equivalent impedance for:

[0103] (9)

[0104] in, This is the line impedance resistance value. This represents the line impedance inductance value.

[0105] The output power of the VSG is expressed as:

[0106] (10)

[0107] in, This refers to the output voltage of the inverter. This is the grid voltage. The system power angle and impedance angle are... This is the equivalent impedance angle.

[0108] When active power changes, reactive power remains constant by adjusting the power angle and amplitude of the virtual reactance. Taking the partial derivative of equation (10), we get:

[0109] (11)

[0110] (1) Only change the virtual impedance angle (keep) If the angle remains unchanged, then the change in angle is:

[0111] (12)

[0112] (2) Only change the virtual impedance magnitude (keep) (Unchanged) The change in amplitude can be obtained as:

[0113] (13)

[0114] The variable relationships of the virtual impedance are given as follows:

[0115] (14)

[0116] in, For virtual impedance, This is the virtual impedance angle. This is a virtual reactance.

[0117] To each and Taking the partial derivative, we get:

[0118] (15)

[0119] right and Taylor expansion yields:

[0120] (16)

[0121] Substituting equation (15) into equation (16), we get:

[0122] (17)

[0123] in, At the same time, disturbances in the line impedance are ignored, i.e. , Substituting equations (12) and (13) into equation (17), the virtual impedance tuning formula is as follows:

[0124] (18)

[0125] in, and These are the steady-state values ​​of the virtual inductance and virtual resistance.

[0126] By adjusting the parameters of the inverter control loop through adaptive virtual impedance, the equivalent impedance between the inverter output point and the grid connection point is made approximately inductive, thus satisfying the requirements of... , The total equivalent resistance is... It is the total equivalent reactance.

[0127] (19)

[0128] Substituting equation (19) into equation (10), its output power can be simplified to:

[0129] (20)

[0130] Adding an adaptive virtual impedance control loop can reduce power coupling and achieve initial decoupling of active and reactive power, which is beneficial to achieving the control objective of "active frequency regulation and reactive voltage regulation".

[0131] As a refinement of the above embodiments, the active power control loop formula is as follows:

[0132] ,

[0133] in, For rotational inertia, The droop control frequency modulation coefficient. This is the active power output value. is the damping coefficient.

[0134] As a refinement of the above embodiments, the voltage and current dual-loop control is the same as the general grid-type control dual-loop structure. Through the hierarchical coordination of the outer voltage loop and the inner current loop, the output performance of the inverter is adjusted.

[0135] It should be noted that this invention reconstructs the grid-based renewable energy control method from two dimensions to achieve decoupling of active and reactive power responses. On one hand, virtual impedance control dynamically compensates for the coupling effects between the active and reactive power loop responses caused by non-purely inductive factors in the line. On the other hand, a voltage feedforward pre-compensation stage is introduced into the reactive power control loop, and a dynamic voltage compensation path is designed. This dynamically pre-compensates for the voltage fluctuations caused by changes in the power angle during active power changes, thereby reducing the impact on reactive power dynamics. It can adaptively calculate the theoretical value of the internal potential based on the virtual power angle changes during the active power response process and dynamically change its magnitude, reducing the impact of voltage differences introduced by power angle changes on the reactive power response.

[0136] like Figure 4 As shown, without the introduction of a power decoupling method, when the active power increases by a step (from 0.5 pu to 2.0 pu) in 1 second, the reactive power exhibits a significant disturbance. Its output experiences a momentary drop at the initial stage of the step, with a minimum amplitude of approximately 0.86 pu, and gradually recovers to its steady-state value after about 0.5 seconds. This phenomenon indicates that in conventional virtual synchronous machine control, the power angle change caused by the active power loop regulation not only affects the system's active power output but also causes fluctuations in the port voltage amplitude, leading to dynamic disturbances in reactive power, demonstrating strong active and reactive power dynamic coupling characteristics.

[0137] and Figure 5 The system's response characteristics after incorporating the method proposed in this patent are demonstrated. It can be observed that under the same active power step, reactive power experiences only a very small fluctuation (minimum amplitude of approximately 0.97 pu) and can quickly recover to steady-state output. Figure 4 In comparison, the transient drop in reactive power is significantly reduced, and the dynamic response time is significantly shortened, indicating that this method effectively suppresses the dynamic shift of reactive components during active power disturbances. The coupling effect between the active and reactive power components of the system is significantly weakened.

[0138] Therefore, the power decoupling scheme proposed in this patent can significantly eliminate reactive power disturbances caused by rapid changes in active power, ensuring independent regulation and stable output of power components. This method not only improves the power coordination characteristics of the system during dynamic processes, but also enhances the voltage support capability and dynamic adaptability of the grid-connected inverter under weak grid conditions, providing effective control support for the stable operation of high-penetration distributed power sources.

[0139] Example 2

[0140] Combination Figure 6 As shown, this disclosure provides a power decoupling device 300 for voltage feedforward compensation and adaptive virtual impedance coordinated control, including a processor 304 and a memory 301. Optionally, the device may further include a communication interface 302 and a bus 303. The processor 304, communication interface 302, and memory 301 can communicate with each other via the bus 303. The communication interface 302 can be used for information transmission. The processor 304 can call logic instructions in the memory 301 to execute the power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control described in the above embodiment.

[0141] Furthermore, the logic instructions in the aforementioned memory 301 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0142] The memory 301, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 304 executes functional applications and data processing by running the program instructions / modules stored in the memory 301, thereby realizing the power decoupling method of voltage feedforward compensation and adaptive virtual impedance coordinated control in the above embodiments.

[0143] The memory 301 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 301 may include high-speed random access memory and may also include non-volatile memory.

[0144] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to perform the aforementioned power decoupling method of voltage feedforward compensation and adaptive virtual impedance coordinated control.

[0145] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0146] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and other media capable of storing program code. It can also be a transient storage medium.

[0147] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0148] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0149] The methods and products (including but not limited to devices and equipment) disclosed in the embodiments herein can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed between each other may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0150] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control, characterized in that, Includes the following steps: Obtain the grid current and grid voltage, and calculate the measured values ​​of the grid's reactive power and active power; Virtual synchronous machine control is performed based on the measured values ​​of reactive power, active power, reactive power reference value, and active power reference value. A voltage feedforward pre-compensation term is introduced into the reactive power control loop to dynamically compensate for voltage deviation caused by changes in power angle based on changes in active power. Calculate the reactive power control loop after VSG compensation based on the voltage feedforward pre-compensation term, and obtain the VSG output side voltage and instantaneous angular frequency based on the VSG active power control loop and reactive power control loop. Adaptive virtual impedance control is adopted, the adaptive virtual impedance reference value is calculated, and the line impedance is dynamically adjusted based on the adaptive virtual impedance reference value, VSG output voltage and instantaneous angular frequency. The voltage loop input command voltage is calculated based on the line impedance. The command voltage is input to the voltage and current dual-loop control to generate SVPWM control command, which is then used to adjust the inverter output performance via SVPWM. The compensation voltage difference of the voltage feedforward pre-compensation term The calculation formula is: ， in, The compensated VSG reference voltage command value. For the VSG output side voltage, This is the grid-side voltage. The power factor angle, The impedance angle of the line. The system's power angle; The virtual impedance tuning formula in the adaptive virtual impedance control is as follows: ， ， ， ， in, For virtual resistance, For virtual inductance, This is the steady-state value of the virtual inductance. This is the steady-state value of the virtual resistance. For dynamic virtual resistance, This represents the virtual reactance steady-state value. This is the virtual impedance steady-state value. For dynamic virtual inductance, This is the virtual impedance angle. This is the change in virtual impedance angle. For virtual impedance, This is the virtual impedance change. This represents the change in virtual reactance. The instantaneous angular frequency, The total equivalent impedance is... This is the grid-side voltage. It is the equivalent impedance angle. This represents the change in active power. This is the measured value of active power. This is the measured value of reactive power. This is the system power angle.

2. The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control according to claim 1, characterized in that, The system power angle is as follows: ， in, The instantaneous angular frequency, The rated angular frequency; The power factor angle is as follows: ， in, This is a reference value for reactive power. This is a reference value for active power.

3. The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control according to claim 2, characterized in that, The post-compensation reactive power control loop calculated based on the voltage feedforward pre-compensation term is as follows: ， in, The reactive inertia coefficient of VSG. This is a reference value for reactive power. This is the measured value of reactive power. The reactive power droop factor of VSG. This is the VSG reference voltage command value.

4. The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control according to claim 2, characterized in that, The voltage loop input command voltage is calculated as follows: ， in, For voltage loop Shaft reference voltage, for Shaft VSG output current, for Shaft VSG output current, For voltage loop Shaft reference voltage.

5. The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control according to claim 4, characterized in that, The formula for the active power control loop is as follows: ， in, For rotational inertia, The droop control frequency modulation coefficient. This is the measured value of active power. is the damping coefficient.

6. The power decoupling method for voltage feedforward compensation and adaptive virtual impedance coordinated control according to claim 1, characterized in that, The voltage and current dual-loop control has the same structure as the grid-type control dual-loop control. Through the hierarchical coordination of the outer voltage loop and the inner current loop, the output performance of the inverter can be adjusted.

7. A power decoupling device for voltage feedforward compensation and adaptive virtual impedance coordinated control, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute, when running the program instructions, the power decoupling method of voltage feedforward compensation and adaptive virtual impedance coordinated control as described in any one of claims 1 to 6.

8. A storage medium storing program instructions, characterized in that, When the program instructions are executed, they perform the power decoupling method of voltage feedforward compensation and adaptive virtual impedance coordinated control as described in any one of claims 1 to 6.

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