A hybrid control method and system for tracking and constructing networks based on frequency domain decoupling and phase reuse.

Abstract

A hybrid control method and system based on frequency domain decoupling and phase reuse for grid-connected and grid-connected converters is proposed. The method involves acquiring the three-phase voltage and current at the grid connection point, decoupling them through multi-stage vector delay superposition to obtain the low-frequency fundamental components of the three-phase voltage, the low-frequency fundamental components of the three-phase current, and the high-frequency transient components of the three-phase current. The low-frequency fundamental components of the three-phase voltage and current are then output as a fundamental voltage reference value and a synchronization phase angle via a low-frequency grid-connected main channel. The synchronization phase angle and the high-frequency transient components of the three-phase current at the grid connection point are then output as a high-frequency compensation voltage command via a high-frequency grid-connected channel. The fundamental voltage reference value and the high-frequency compensation voltage command are superimposed in the time domain and modulated by PWM to form the drive signal for the grid-connected converter. This achieves a hybrid control strategy based on single-machine frequency domain channel parallel decoupling and phase-locked loop-free phase reuse for grid-connected and grid-connected converters.

Description

Technical Field

[0001] This invention belongs to the field of power electronics and power system control technology, specifically, it relates to a hybrid control method and system for following and building networks based on frequency domain decoupling and phase reuse. Background Technology

[0002] As a key component of the renewable energy grid connection interface, the control technology of grid-connected converters directly affects the safe and stable operation of the power system. Currently, the control strategies for grid-connected converters are mainly divided into two categories: grid-following and grid-connecting. Traditional grid-following control strategies treat the converter as a controlled current source, tracking the grid voltage phase in real time through a phase-locked loop. This approach offers advantages such as simple control structure, fast dynamic response, and high-quality grid-connected current, making it widely applicable in strong grid environments. Grid-connecting control strategies, on the other hand, simulate the external characteristics of a synchronous generator to establish and maintain the voltage and frequency at the grid connection point, enabling the converter to exhibit voltage source characteristics. This provides inertia support and damping for the grid, making it suitable for weak grids or islanded operation scenarios. With the increasing penetration rate of renewable energy, the power grid exhibits characteristics of low inertia and low short-circuit ratios, making single grid-following or grid-connecting control insufficient to meet the grid connection requirements under complex operating conditions. Therefore, hybrid grid-following / grid-connecting control technology, combining the advantages of both, has become a hot topic.

[0003] However, existing hybrid control technologies for grid-connected converters still face many severe challenges in practical applications, making it difficult to simultaneously achieve both steady-state support performance and transient dynamic response. Firstly, most existing hybrid control schemes adopt a "parameter fusion" approach, attempting to simultaneously achieve steady-state grid connection and transient grid connection functions within the same control loop by adjusting control parameters. This full-frequency-domain parameter coupling leads to mutual constraints on the dynamic and steady-state performance of the control system. For example, increasing the droop coefficient to improve voltage stiffness in the low-frequency range often sacrifices damping performance in the high-frequency range, resulting in slow system adjustment when facing sudden load changes and extremely difficult parameter tuning.

[0004] Secondly, while existing hybrid control strategies introduce grid-type branches, independent phase-locked loop (PLL) units are still commonly retained in the grid-following branches responsible for high-frequency damping or fast current control to obtain synchronization phase. In weak power grids, especially extremely weak ones, the point of common coupling voltage fluctuates drastically due to line impedance, easily causing oscillations or even loss of synchronization in the PLL output phase. This phase observation error forms positive feedback through the control loop, triggering wideband oscillations in the system and even causing the converter to disconnect from the grid.

[0005] Furthermore, while some proposed mode-switching schemes based on harmonic power detection attempt to address the aforementioned issues by switching control modes under different operating conditions, this detection-based switching logic inherently suffers from detection delays and is prone to sudden changes in control power during mode switching, leading to secondary transient impacts and affecting the smooth operation of the system. Therefore, a new control architecture is needed that can completely decouple steady-state grid requirements from transient grid-following requirements at the physical level and eliminate the dependence on phase-locked loops (PLLs) under weak grid conditions, thereby achieving adaptive and stable operation of the converter under all operating conditions. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a hybrid control method and system for grid connection and grid construction based on frequency domain decoupling and phase reuse. This method is applied to converter control in high-penetration renewable energy grid-connected environments. It realizes a hybrid control strategy for grid connection and grid construction based on single-machine frequency domain channel parallel decoupling and phase-locked loop (PLL)-free phase reuse. This solves the instability risk of traditional grid-connected converters under weak grid conditions caused by PLL coupling, as well as the technical challenge of balancing steady-state support and transient response in existing hybrid control strategies.

[0007] The present invention adopts the following technical solution.

[0008] This invention proposes a hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse, comprising: The three-phase voltage and three-phase current at the grid connection point are collected, and the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current are obtained through multi-level vector delay superposition and decoupling. The low-frequency fundamental components of the three-phase voltage and the three-phase current are input into the low-frequency grid main channel, and the fundamental voltage reference value and the synchronization phase angle are output. The high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point are input into the high-frequency grid follower channel, and the high-frequency compensation voltage command is output. The fundamental voltage reference value and the high-frequency compensation voltage command are superimposed in the time domain and modulated by PWM to obtain the drive signal of the grid-connected converter; The driving signals are used to perform mixed control of the following net and the construction net.

[0009] The transfer function of the superposition of vector delays at each stage is established by utilizing the delay time and phase compensation angle; Different delay times are set for the transfer functions of the vector delay superposition at each level; the transfer functions of the vector delay superposition at each level are cascaded to obtain a multi-level vector delay superposition decoupling unit; The three-phase voltage and three-phase current at the grid connection point are processed by a multi-stage vector delay superposition decoupling unit to obtain the low-frequency fundamental component of the three-phase voltage and the low-frequency fundamental component of the three-phase current at the grid connection point. The difference between the three-phase current at the grid connection point and the low-frequency fundamental component is taken as the high-frequency transient component of the three-phase current; the difference between the three-phase voltage at the grid connection point and the low-frequency fundamental component is taken as the high-frequency transient component of the three-phase voltage at the grid connection point.

[0010] No. The transfer function for the superposition of time delays of vectors is shown in the following equation:

[0011]

[0012] In the formula, For the first The transfer function of superposition of vector delays. , For a series, For phase compensation angle, To delay time, For frequency domain operators, Angular velocity at the fundamental frequency. The period is the fundamental frequency.

[0013]

[0014] In the formula, It is a positive integer. This represents the harmonic order.

[0015] Clark transform is performed on the low-frequency fundamental components of the three-phase voltage and the three-phase current to obtain the fundamental voltage in a two-phase stationary coordinate system. Components, fundamental wave of current Quantity; Using the fundamental wave of voltage Components, fundamental wave of current The actual values ​​of active power and reactive power of the component calculation system; Based on the phase synchronization loop control law of active power deviation, the actual value of active power is input into the virtual rotor motion equation to calculate the synchronization phase angle; Based on the reactive power-voltage integral control law, the actual value of reactive power is input into the virtual excitation regulation formula to calculate the voltage amplitude. exist In a synchronously rotating coordinate system, The axis is oriented in the direction of the voltage vector, and the fundamental voltage reference value vector is constructed based on the voltage amplitude; The fundamental voltage reference value generated by the low-frequency network channel is equal to the voltage amplitude.

[0016] Synchronization phase angle As shown in the following formula:

[0017] In the formula, The active power setpoint, The rated angular frequency, For proportional gain, For integral gain, This is the actual value of active power. This represents the actual value of reactive power. , All are set durations.

[0018] voltage amplitude As shown in the following formula:

[0019] In the formula, The given value for reactive power. This is the rated voltage amplitude. The time constant of the reactive power loop integral is... This is the voltage damping coefficient. Actual value of grid connection point voltage Compared with reference value deviation, .

[0020] exist In a synchronously rotating coordinate system, The axis is oriented in the direction of the voltage vector, according to the voltage amplitude. The constructed fundamental voltage reference vector is shown in the following equation:

[0021] In the formula, , for The components of the fundamental voltage reference value in a synchronously rotating coordinate system.

[0022] Using the synchronous phase angle, the high-frequency transient components of the three-phase current are subjected to Park transform to obtain... High-frequency harmonics of current in a synchronous rotating coordinate system Quantity; Construct a second-order linear generalized total disturbance real-time estimator, and High-frequency harmonics of current in a synchronous rotating coordinate system The component inputs are fed into a second-order linear generalized total disturbance real-time estimator to obtain the real-time state estimates of the high-frequency current, the high-frequency current derivative, and the total disturbance. Based on the real-time state estimate of the high-frequency current, the high-frequency current derivative, and the total disturbance, the high-frequency compensation voltage command corresponding to the control frequency bandwidth is calculated.

[0023] Another aspect of this invention proposes a hybrid control system for tracking and constructing networks based on frequency domain decoupling and phase reuse, comprising: The component decoupling module is used to collect the three-phase voltage and three-phase current at the grid connection point, and obtain the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current at the grid connection point through multi-level vector delay superposition decoupling. The low-frequency processing module is used to input the low-frequency fundamental components of the three-phase voltage and the three-phase current into the low-frequency grid main channel, and output the fundamental voltage reference value and the synchronization phase angle. The high-frequency processing module is used to input the high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point into the high-frequency grid slave channel and output the high-frequency compensation voltage command. The modulation module is used to superimpose the fundamental voltage reference value and the high-frequency compensation voltage command in the time domain, and obtain the drive signal of the grid-connected converter through PWM modulation. The drive signal is used to perform mixed control of grid connection and grid connection.

[0024] The present invention is also a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the method.

[0025] The present invention is also a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method.

[0026] The beneficial effects of this invention are that, compared with the prior art, it at least includes: 1) This invention utilizes a multi-stage vector delay superposition decoupling unit to achieve high-precision frequency domain physical isolation. Unlike traditional filter banks which suffer from phase lag and slow dynamic response, this invention employs a multi-stage vector delay superposition decoupling unit. Utilizing the principle of periodic delay superposition of spatial vectors, it can accurately eliminate specific subharmonics and negative sequence components in the power grid signal. In the low-frequency band, it ensures that the grid connection channel obtains a pure fundamental positive sequence signal, preventing harmonic interference and ensuring synchronization stability. In the high-frequency band, it ensures that the grid connection channel can capture complete broadband transient disturbances, achieving a full-band, dead-angle-free response to power grid disturbances. 2) This invention, based on phase self-synchronization control using power deviation integral, completely eliminates the root cause of instability in weak power grids. This invention abandons the phase-locked loop (PLL), an essential component of traditional grid-following control, and utilizes the inherent integral synchronization mechanism of power and angle to achieve phase self-synchronization. This method, in principle, cuts off the positive feedback loop of voltage fluctuation-PLL oscillation-current distortion commonly found in extremely weak power grids, giving the system strong robustness similar to that of flexible DC transmission, enabling it to maintain stable operation even when the power grid is extremely fragile or even in islanded conditions. 3) This invention achieves decoupled design of control parameters. Due to the introduction of frequency domain current splitting, the system's steady-state parameters mainly act on the low-frequency channel, while the transient parameters mainly act on the high-frequency channel. Both are confined to different frequency bands and do not interfere with each other. This greatly reduces the difficulty of tuning the control parameters and enhances its engineering practicality. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall control principle of the hybrid control of the tracking network and the network structure based on frequency domain decoupling and phase reuse proposed in this invention; Figure 2 This is the control block diagram of the multi-level vector delay superposition decoupling unit proposed in this invention; Figure 3 This is the control block diagram of the low-frequency network main channel proposed in this invention; Figure 4 This is the control block diagram of the high-frequency follower channel proposed in this invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention proposes a hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse. The overall control block principle is as follows: Figure 1 As shown, the DC power supply is connected to the power grid via a grid-connected converter, and the three-phase voltage at the grid connection point PCC is... and three-phase current The low-frequency fundamental component of the three-phase voltage at the grid connection point is obtained through multi-stage vector delay superposition and decoupling. Low-frequency fundamental component of the three-phase current at the grid connection point High-frequency transient components of the three-phase current at the grid connection point The low-frequency fundamental component of the three-phase voltage at the grid connection point Low-frequency fundamental component of the three-phase current at the grid connection point Reference value of fundamental voltage output from the main channel of the low-frequency grid and synchronization phase angle Synchronization phase angle High-frequency transient components of the three-phase current at the grid connection point High-frequency compensation voltage command is output from the high-frequency network channel. Fundamental voltage reference value and high-frequency compensation voltage command After being superimposed in the time domain, the signal is modulated by PWM to become the drive signal for the grid-connected converter.

[0030] Specifically, the method includes the following steps: Step 1: Collect the three-phase voltage at the grid connection point. and three-phase current .

[0031] Step 2, three-phase voltage at the grid connection point and three-phase current The low-frequency fundamental component of the three-phase voltage at the grid connection point is obtained through multi-stage vector delay superposition and decoupling. Low-frequency fundamental component of three-phase current High-frequency transient components of three-phase current .

[0032] This invention proposes a frequency domain division based on a multi-level vector delay superposition decoupling unit. The three-phase voltage signal and three-phase current signal of the PCC point are sent to the multi-level vector delay superposition decoupling unit in real time. This step uses the principle of spatial vector periodic delay superposition to physically separate the input signal into a low-frequency fundamental component and a high-frequency transient component. Then the signals are respectively entered into a dual-channel parallel processing step.

[0033] The control block diagram of the multi-level vector delay superposition decoupling unit disclosed in this invention is as follows: Figure 2 As shown, step 2 includes the following steps: Step 2.1: Establish the transfer function of the superposition of vector delays at each stage using the delay time and phase compensation angle. , , It is a series; No. The transfer function for the superposition of time delays of vectors is shown in the following equation:

[0034]

[0035] In the formula, For phase compensation angle, To delay time, For frequency domain operators, Angular velocity at the fundamental frequency. The period is the fundamental frequency.

[0036] Step 2.2: Set different delay times for the transfer functions of the vector delay superposition at each level; cascade the transfer functions of the vector delay superposition at each level to obtain a multi-level vector delay superposition decoupling unit.

[0037] The transfer function of the vector delay superposition at each level is to rotate the delayed fundamental vector back to the phase of the current moment, so that it is superimposed with the signal without delay.

[0038] Specifically, in order to eliminate the specified The second harmonic must be such that the transfer function is in The gain at the second harmonic frequency is 0, that is... When the exponent is When it is an odd multiple, the following relationship exists:

[0039] Then Substitute the values ​​to obtain the delay time. The general design formula is as follows:

[0040] To ensure the system has the fastest dynamic response speed, the delay time... It should be the smallest possible positive number, therefore a suitable integer needs to be chosen. To calculate the smallest positive integer .

[0041] Step 2.3, Three-phase voltage at the grid connection point and three-phase current The low-frequency fundamental component of the three-phase voltage at the grid connection point is obtained through a multi-stage vector delay superposition decoupling unit. Low-frequency fundamental component of the three-phase current at the grid connection point .

[0042] In actual operation, the three-phase signal may contain multiple high-frequency harmonics. Therefore, in order to extract the pure fundamental component, it is necessary to set different delay times. The transfer functions of vector delay superposition are cascaded to eliminate multiple harmonic components of a specified frequency, thus obtaining the low-frequency fundamental component of the three-phase voltage at the grid connection point. Low-frequency fundamental component of the three-phase current at the grid connection point .

[0043] Step 2.4, Three-phase current at grid connection point With low-frequency fundamental component The difference is taken as the high-frequency transient component of the three-phase current at the grid connection point. ; Three-phase voltage at grid connection point With low-frequency fundamental component The difference is taken as the high-frequency transient component of the three-phase voltage at the grid connection point. .

[0044] Step 3, Low-frequency fundamental component of the three-phase voltage at the grid connection point Low-frequency fundamental component of the three-phase current at the grid connection point Reference value of fundamental voltage output from the main channel of the low-frequency grid and synchronization phase angle .

[0045] In the low-frequency main channel of the network, the synchronization phase angle is determined by the phase synchronization loop control law based on the active power deviation, and the voltage amplitude is determined as the fundamental voltage reference value based on the reactive power-voltage integral control law.

[0046] This invention constructs a frequency domain division of labor and collaborative control architecture with a fixed fundamental wave in the main channel of the grid and a harmonic compensation in the follow-up channel. It achieves frequency domain allocation of electrical quantities through multi-level vector delay superposition decoupling and eliminates additional synchronization links through phase reuse. Compared with existing switching, fusion and compensation hybrid control schemes, this invention has theoretical advantages in terms of control structure simplicity, grid strength adaptability and harmonic suppression capability.

[0047] This invention establishes a low-frequency grid-connecting main channel. This channel utilizes a phase self-synchronization control strategy based on power deviation integral. Through the active power integral feedback mechanism of the power synchronization loop, it simulates the electromechanical transient characteristics of the synchronous machine rotor, directly anchoring to the grid frequency without a phase-locked loop (PLL), generating a unique synchronization phase angle for the entire system. Using a reactive power-voltage integral control law, by integrally adjusting the reactive power deviation and introducing a voltage damping element, it achieves error-free regulation and rigid support of the PCC point voltage, while simultaneously outputting a fundamental voltage reference value. Furthermore, in traditional schemes, the grid-connecting channel relies on an independent PLL, which can become a source of instability in weak grids. This invention reuses the phase angle of the grid-connecting channel, enabling harmonic compensation of the grid-connecting channel to be completed within the stable coordinate system established by the grid-connecting channel. The two are naturally synchronized on the phase reference, requiring no additional synchronization element.

[0048] The control block diagram of the low-frequency network main channel disclosed in this invention is as follows: Figure 3 As shown, step 3 includes the following steps: Step 3.1, analyze the low-frequency fundamental component of the three-phase voltage at the grid connection point. Low-frequency fundamental component of the three-phase current at the grid connection point Perform a Clark transformation to obtain the fundamental voltage in the two-phase stationary coordinate system. Quantity , The fundamental wave of the current Quantity , ; Step 3.2, using the fundamental frequency of the voltage Quantity , The fundamental wave of the current Quantity , Calculate the actual value of the active power of the system and actual reactive power value As shown in the following formula:

[0049] Step 3.3: Based on the phase synchronization loop control law of active power deviation, the actual value of active power is... Input the motion equation of the virtual rotor and calculate the synchronization phase angle. As shown in the following formula:

[0050] In the formula, The active power setpoint, The rated angular frequency, For proportional gain, virtual damping is provided to suppress power oscillations. For the integral gain, a virtual inertia is provided to determine the rate of change of the system frequency. , All are set durations.

[0051] Step 3.4, based on the reactive power-voltage integral control law, the actual value of reactive power is... The voltage amplitude is calculated by inputting it into the virtual excitation regulation formula. As shown in the following formula:

[0052] In the formula, The given value for reactive power. This is the rated voltage amplitude. The time constant of the reactive power loop integral is... This is the voltage damping coefficient. Actual value of grid connection point voltage Compared with reference value deviation, .

[0053] Step 3.5, in In a synchronously rotating coordinate system, The axis is oriented in the direction of the voltage vector, according to the voltage amplitude. The constructed fundamental voltage reference vector is shown in the following equation:

[0054] In the formula, , for Components of the fundamental voltage reference value in a synchronously rotating coordinate system; Reference value of fundamental voltage generated by low-frequency network channel equal .

[0055] Step 4, Synchronize Phase Angle High-frequency transient components of the three-phase current at the grid connection point High-frequency compensation voltage command is output from the high-frequency network channel. .

[0056] This invention establishes a high-frequency follow-the-network channel that receives high-frequency transient components. Its core feature is the elimination of the independent phase-locked loop (PLL). Synchronization phase angles generated by the master channel are directly read and forcibly reused. The Park transformation is performed to treat parameter drift, frequency coupling, and harmonic interference under weak power grid conditions as a total disturbance state for real-time observation, and the feedforward channel is used to directly cancel them, finally outputting a high-frequency compensation voltage command.

[0057] The control block diagram of the high-frequency follower channel provided by this invention is as follows: Figure 4 As shown, step 4 includes the following steps: Step 4.1, using the synchronization phase angle The high-frequency transient components of the three-phase current Perform the Park transformation to obtain High-frequency harmonics of current in a synchronous rotating coordinate system Quantity , :

[0058] In the formula, , , It represents the high-frequency transient component of the three-phase current at the grid connection point.

[0059] Step 4.2: Construct a second-order linear generalized total disturbance real-time estimator, which will... High-frequency harmonics of current in a synchronous rotating coordinate system Quantity , The input is fed into a second-order linear generalized total disturbance real-time estimator to obtain real-time state estimates of the high-frequency current, the high-frequency current derivative, and the total disturbance. Taking the d-axis component as an example, its differential equation expression in the continuous time domain is as follows:

[0060] In the formula, , , These are the real-time state estimates of the high-frequency current, the derivative of the high-frequency current, and the total disturbance, respectively. , , These are the real-time state estimates. , , The derivative with respect to time, For observation error, To control the gain, , , They are respectively , , Error feedback gain, To control the input.

[0061] Step 4.3: Based on the principle of disturbance cancellation, calculate the high-frequency compensation voltage command corresponding to the control frequency bandwidth according to the real-time state estimate of the high-frequency current, the high-frequency current derivative, and the total disturbance. The high-frequency compensation voltage command vector along the d-axis is shown in the following formula:

[0062] In the formula, This is the high-frequency compensation voltage command vector along the d-axis. To control frequency bandwidth, the -z3 term is used to cancel out total disturbances. Used to configure the error convergence dynamics of the closed-loop system.

[0063] The q-axis control structure is exactly the same as the d-axis control structure.

[0064] Step 5, Fundamental voltage reference value and high-frequency compensation voltage command After being superimposed in the time domain, the signal is modulated by PWM to become the drive signal for the grid-connected converter.

[0065] Specifically, step 5 includes: Step 5.1: Superimpose the fundamental voltage reference value vector with the high-frequency compensation voltage command vector in the entire time domain to obtain the modulation voltage vector, as shown in the following equation:

[0066] In the formula, , for The components of the modulated voltage in a synchronously rotating coordinate system; Step 5.2, using the synchronization phase angle The modulation voltage vector is then subjected to an inverse Park transform to obtain the final modulation voltage. The modulated voltage generates the switching signal for the grid-connected inverter through PWM.

[0067] Another aspect of this invention proposes a hybrid control system for tracking and constructing networks based on frequency domain decoupling and phase reuse, comprising: The component decoupling module is used to collect the three-phase voltage and three-phase current at the grid connection point, and obtain the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current at the grid connection point through multi-level vector delay superposition decoupling. The low-frequency processing module is used to input the low-frequency fundamental components of the three-phase voltage and the three-phase current into the low-frequency grid main channel, and output the fundamental voltage reference value and the synchronization phase angle. The high-frequency processing module is used to input the high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point into the high-frequency grid slave channel and output the high-frequency compensation voltage command. The modulation module is used to superimpose the fundamental voltage reference value and the high-frequency compensation voltage command in the time domain, and obtain the drive signal of the grid-connected converter through PWM modulation. The drive signal is used to perform mixed control of grid connection and grid connection.

[0068] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0069] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0070] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0071] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse, characterized in that, include: The three-phase voltage and three-phase current at the grid connection point are collected, and the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current are obtained through multi-level vector delay superposition and decoupling. The low-frequency fundamental components of the three-phase voltage and the three-phase current are input into the low-frequency grid main channel, and the fundamental voltage reference value and the synchronization phase angle are output. The high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point are input into the high-frequency grid follower channel, and the high-frequency compensation voltage command is output. The fundamental voltage reference value and the high-frequency compensation voltage command are superimposed in the time domain and modulated by PWM to obtain the drive signal of the grid-connected converter; The driving signal is used to perform mixed control of the follow net and the structure net.

2. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase multiplexing according to claim 1, characterized in that, The three-phase voltage and three-phase current at the grid connection point are collected, and after multi-stage vector delay superposition and decoupling, the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current at the grid connection point are obtained, including: The transfer function of the superposition of vector delays at each stage is established by utilizing the delay time and phase compensation angle; Different delay times are set for the transfer functions of the vector delay superposition at each level; the transfer functions of the vector delay superposition at each level are cascaded to obtain a multi-level vector delay superposition decoupling unit; The three-phase voltage and three-phase current at the grid connection point are processed by a multi-stage vector delay superposition decoupling unit to obtain the low-frequency fundamental component of the three-phase voltage and the low-frequency fundamental component of the three-phase current at the grid connection point. The difference between the three-phase current at the grid connection point and the low-frequency fundamental component is taken as the high-frequency transient component of the three-phase current; the difference between the three-phase voltage at the grid connection point and the low-frequency fundamental component is taken as the high-frequency transient component of the three-phase voltage at the grid connection point.

3. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase multiplexing according to claim 2, characterized in that, No. The transfer function for the superposition of time delays of vectors is shown in the following equation: In the formula, For the first The transfer function of superposition of vector delays. , For a series, For phase compensation angle, To delay time, For frequency domain operators, Angular velocity at the fundamental frequency. The period is the fundamental frequency.

4. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 3, characterized in that, In the formula, It is a positive integer. This represents the harmonic order.

5. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 3, characterized in that, The low-frequency fundamental components of the three-phase voltage and the three-phase current are input into the low-frequency grid main channel, and the fundamental voltage reference value and synchronization phase angle are output, including: Clark transform is performed on the low-frequency fundamental components of the three-phase voltage and the three-phase current to obtain the fundamental voltage in a two-phase stationary coordinate system. Components, fundamental wave of current Quantity; Using the fundamental wave of voltage Components, fundamental wave of current The actual values ​​of active power and reactive power of the component calculation system; Based on the phase synchronization loop control law of active power deviation, the actual value of active power is input into the virtual rotor motion equation to calculate the synchronization phase angle; Based on the reactive power-voltage integral control law, the actual value of reactive power is input into the virtual excitation regulation formula to calculate the voltage amplitude. exist In a synchronously rotating coordinate system, The axis is oriented in the direction of the voltage vector, and the fundamental voltage reference value vector is constructed based on the voltage amplitude; The fundamental voltage reference value generated by the low-frequency network channel is equal to the voltage amplitude.

6. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 5, characterized in that, Synchronization phase angle As shown in the following formula: In the formula, The active power setpoint, The rated angular frequency, For proportional gain, For integral gain, This is the actual value of active power. , All are set durations.

7. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 5, characterized in that, voltage amplitude As shown in the following formula: In the formula, The given value for reactive power. This represents the actual value of reactive power. This is the rated voltage amplitude. The time constant of the reactive power loop integral is... This is the voltage damping coefficient. Actual value of grid connection point voltage Compared with reference value deviation, .

8. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 5, characterized in that, exist In a synchronously rotating coordinate system, The axis is oriented in the direction of the voltage vector, according to the voltage amplitude. The constructed fundamental voltage reference vector is shown in the following equation: In the formula, , for The components of the fundamental voltage reference value in a synchronously rotating coordinate system.

9. The hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase reuse according to claim 2, characterized in that, The high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point are input into the high-frequency grid slave channel, and the high-frequency compensation voltage command is output, including: Using the synchronous phase angle, the high-frequency transient components of the three-phase current are subjected to Park transform to obtain... High-frequency harmonics of current in a synchronous rotating coordinate system Quantity; Construct a second-order linear generalized total disturbance real-time estimator, and High-frequency harmonics of current in a synchronous rotating coordinate system The component inputs are fed into a second-order linear generalized total disturbance real-time estimator to obtain the real-time state estimates of the high-frequency current, the high-frequency current derivative, and the total disturbance. Based on the real-time state estimate of the high-frequency current, the high-frequency current derivative, and the total disturbance, the high-frequency compensation voltage command corresponding to the control frequency bandwidth is calculated.

10. A hybrid control system for tracking and constructing networks based on frequency domain decoupling and phase multiplexing, used to implement the hybrid control method for tracking and constructing networks based on frequency domain decoupling and phase multiplexing as described in any one of claims 1 to 9, characterized in that, include: The component decoupling module is used to collect the three-phase voltage and three-phase current at the grid connection point, and obtain the low-frequency fundamental component of the three-phase voltage, the low-frequency fundamental component of the three-phase current, and the high-frequency transient component of the three-phase current at the grid connection point through multi-level vector delay superposition decoupling. The low-frequency processing module is used to input the low-frequency fundamental components of the three-phase voltage and the three-phase current into the low-frequency grid main channel, and output the fundamental voltage reference value and the synchronization phase angle. The high-frequency processing module is used to input the high-frequency transient components of the synchronization phase angle and the three-phase current at the grid connection point into the high-frequency grid slave channel and output the high-frequency compensation voltage command. The modulation module is used to superimpose the fundamental voltage reference value and the high-frequency compensation voltage command in the time domain, and then modulate them with PWM to obtain the drive signal of the grid-connected converter. The drive signal is used to perform mixed control of the grid connection and grid connection.

11. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-9.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-9.

Images