Hybrid energy storage virtual synchronous generator inertia adaptive control method and system

Abstract

The invention discloses a hybrid energy storage-based virtual synchronous generator inertia adaptive control method, which comprises the following steps of: acquiring three-phase voltage and three-phase current signals output by an alternating current side of a virtual synchronous generator, and calculating the output power of the virtual synchronous generator, constructing a virtual rotor mechanical model and a virtual excitation regulator model of the virtual synchronous generator; a Phillips-Heffron model of the virtual synchronous generator is constructed, and a design principle of virtual inertia is obtained; the output frequency of the virtual synchronous generator is used as a control target to carry out traditional self-adaptive adjustment on the virtual inertia, the charge state of the super capacitor is used as a control target on this basis to secondarily adjust the virtual inertia, the virtual inertia is converted into modulation voltage through a virtual impedance environment and a voltage and current double-closed link, PWM modulation is carried out on the obtained modulation voltage, and the modulation voltage is obtained. The inverter can be controlled to track the given voltage, and the inverter can adjust the frequency and the voltage of the power grid.

Description

Technical Field

[0001] The invention relates to a virtual synchronous generator control technology, in particular to an inertia adaptive control method of a virtual synchronous generator based on hybrid energy storage. Background Art

[0002] In order to meet the growing global energy demand and reduce greenhouse gas emissions, renewable energy has been widely connected to modern power systems. As the proportion of synchronous generators continues to decline, the system will show low inertia characteristics. In order to make new energy power generation have a certain inertia support capability, the virtual synchronous generator (VSG) control technology can be introduced in the control of the power electronic converter to simulate the rotor external characteristics of the synchronous generator in the form of an algorithm. However, unlike the synchronous generator, the power electronic converter does not have a physical rotor and cannot absorb / emit any energy, which requires an additional energy device to simulate the rotor kinetic energy of the synchronous generator. Since distributed power generation, such as wind power generation and photovoltaic power generation, often adopts the control strategy of maximum power point tracking and does not have the ability to regulate power, energy storage devices with flexible power regulation are often configured on the DC side for power regulation. In the prior art, a hybrid energy storage device of batteries and supercapacitors is used. Supercapacitors have the characteristics of high power density and low energy density, so they can be used to provide the high-frequency power required by VSG, that is, to simulate the changing power of the synchronous generator rotor kinetic energy during the transient process, and provide inertia support to the system; batteries have the characteristics of high energy density and low power density, so they can be used to provide the low-frequency power required by VSG, that is, to simulate the power provided by the synchronous generator prime mover, and provide steady-state power support to the system. High-pass / low-pass filters are widely used in engineering to achieve the reasonable distribution of high and low-frequency power.

[0003] When VSG is connected to the grid in normal operation, it will inevitably be disturbed by itself and the system, including changes in VSG power instructions and disturbances in the grid frequency. Under the influence of the above disturbances, the output voltage and power of VSG will oscillate. However, as a power electronic equipment, VSG is far less resistant to power shocks and frequency oscillations than traditional synchronous generators. In order to optimize the transient output characteristics of VSG, a VSG inertia adaptive strategy is proposed. The size of the virtual inertia is adaptively adjusted according to the VSG output angular frequency and angular acceleration to optimize the transient output characteristics of VSG.

[0004] When designing the parameters of the virtual synchronous generator adaptively, the DC side is often equivalent to an infinite constant voltage source, which reduces the engineering practicality of the VSG control technology. In addition, due to the neglect of the physical constraints on the DC side, it may cause overcharging and over-discharging of the energy storage equipment, reducing the service life of the equipment. In particular, supercapacitors with low energy density are used to provide virtual kinetic energy for the virtual rotor, which changes frequently during transient processes and is prone to overcharging and over-discharging, which is not conducive to the safe and stable operation of the system. Summary of the invention

[0005] In order to solve the defects existing in the above-mentioned prior art, the present invention provides a VSG inertia adaptive control method based on hybrid energy storage.

[0006] The technical solution adopted by the present invention is: a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage, collecting three-phase voltage and three-phase current signals outputted by the AC side of the virtual synchronous generator, and calculating the output power of the virtual synchronous generator, characterized in that it also includes the following steps:

[0007] S1: A filter is used to distribute the output power of the virtual synchronous generator, and the power is separated by frequency, where the low-frequency power is responded by the battery and the high-frequency power is responded by the supercapacitor. Then, a current single closed-loop control method is adopted to achieve the tracking of the battery and the supercapacitor to their respective reference powers.

[0008] S2: construct a virtual rotor mechanical model and a virtual excitation regulator model of the virtual synchronous generator, and combine the two to obtain the active power outer loop of the virtual synchronous generator, and then obtain the amplitude reference and frequency reference of the virtual excitation voltage;

[0009] S3: Taking the output frequency of the virtual synchronous generator as the first control target, the virtual inertia is adaptively adjusted for the first time, and then taking the supercapacitor charge state as the second control target, the size of the virtual inertia is adjusted for the second time, and the active power outer loop of the virtual synchronous generator in step S2 is corrected to obtain the virtual excitation voltage;

[0010] S4: The virtual excitation voltage is converted into a modulation voltage through a virtual impedance environment and a voltage-current double closed loop, and the obtained modulation voltage is PWM modulated to control the inverter to track the given voltage so as to achieve the inverter's regulation of the grid frequency and voltage, thereby realizing the virtual synchronous generator inertia adaptive control.

[0011] An electronic device comprises: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores commands executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the steps of the above-mentioned method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage.

[0012] A readable storage medium, the readable storage medium is a computer-readable storage medium, the computer-readable storage medium stores a program for implementing a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage, the program for implementing a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage is executed by a processor to implement the steps of the above-mentioned method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage.

[0013] Beneficial effects of the present invention:

[0014] (1) Based on the consideration that the DC side is a hybrid energy storage, in order to make full use of the advantage of the high power density of the supercapacitor, the present invention decomposes the power through the filter, and allocates the high-frequency inertia support power corresponding to the virtual inertia to the supercapacitor. Therefore, the size of the virtual inertia will directly affect the charging and discharging power and the state of charge of the supercapacitor during the transient process. According to the analysis, the maximum value of the change in the state of charge of the supercapacitor during the transient process is proportional to the virtual inertia. In the adaptive control of the virtual inertia, the state of charge of the supercapacitor is taken into account, which can prevent the supercapacitor from being overcharged and over-discharged during the transient process, and improve the dynamic characteristics of the output of the virtual synchronous generator during the transient process.

[0015] (2) The inertia adaptive control strategy proposed in the present invention can improve the dynamic characteristics of the transient frequency response and transient power response of the virtual synchronous generator, and effectively suppress the transient oscillation of the virtual synchronous generator.

[0016] (3) The inertia adaptive control strategy proposed in the present invention can reasonably distribute the power of the supercapacitor and battery hybrid energy storage device on the basis of ensuring that the supercapacitor is not overcharged or over-discharged, and provide a certain steady-state power support and transient inertia support to the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the accompanying drawings described below are only some embodiments. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0018] In the attached picture:

[0019] Figure 1 is a flow chart of a method for secondary adjustment of virtual inertia in an embodiment of the present invention;

[0020] Figure 2 It is the main circuit topology diagram of the virtual synchronous generator based on hybrid energy storage on the DC side;

[0021] Figure 3 It is the block diagram of the DC side hybrid energy storage power distribution control;

[0022] Figure 4 This is the control block diagram of the inner loop of the DC side hybrid energy storage;

[0023] Figure 5 It is the block diagram of active power control of virtual synchronous generator;

[0024] Figure 6 It is a block diagram of reactive power control of virtual synchronous generator;

[0025] Figure 7 It is the Phillips-Heffron model diagram of the virtual synchronous generator;

[0026] Figure 8 It is a block diagram of virtual impedance control of virtual synchronous generator;

[0027] Fig. 9 It is the inner loop control block diagram of virtual synchronous generator.

[0028] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Explanation of the meaning of terms used in this manual:

[0033] Virtual Synchronous Generator (VSG): Through control strategy, the grid-connected inverter simulates the operating mechanism of the synchronous generator and participates in the frequency and voltage regulation of the power grid.

[0034] State of charge (SOC): SOC is a physical quantity used to reflect the remaining capacity of the energy storage unit. A value that is too high or too low will affect the charging and discharging performance and life of the energy storage battery.

[0035] Embodiment 1

[0036] Step S1, calculating the output power of the virtual synchronous generator, firstly collects the signals of the three-phase voltage and three-phase current outputted from the AC side of the virtual synchronous generator in real time, and calculates the output power by instantaneous power theory, which is specifically expressed as shown in formula (1):

[0037]

[0038] Where: P e is the active power output by the inverter, u a ,u b ,u c is the voltage output by the inverter (filter capacitor voltage), i a ,i b ,i c is the current output by the inverter (filtered current).

[0039] It should be noted that in this embodiment, the power calculated using the instantaneous power theory is often accompanied by high-order harmonics and needs to be filtered through a low-pass filter, such as Figure 5 , Figure 6 shown.

[0040] A low-pass filter is used to decompose the output power of the virtual synchronous generator, and the power is separated by frequency, where the low-frequency power is responded by the battery and the high-frequency power is responded by the supercapacitor, so as to realize the distribution between the battery and the supercapacitor. The battery responds to the low-frequency power in the output power of the virtual synchronous generator, simulates the prime mover in the synchronous generator, and provides steady-state power support to the system; the supercapacitor responds to the high-frequency power in the output power of the virtual synchronous generator, simulates the rotor kinetic energy in the synchronous generator, and provides transient inertia support to the system. This part of power is zero in steady state, that is, the supercapacitor output is zero. The DC side hybrid energy storage power distribution control block diagram is as follows: Figure 3 The specific expression is shown in formula (2):

[0041]

[0042] Where: τ is the time constant of the low-pass filter.

[0043] Then, a single closed-loop current control method is adopted to achieve the tracking of the battery and supercapacitor to their respective reference powers, such as Figure 4 As shown in Equation 3, the bandwidth of the inner loop is much larger than that of the outer power loop, and the dynamics of the inner loop are often ignored during transient processes.

[0044]

[0045] Step S2, construct a virtual rotor mechanical model and a virtual excitation regulator model of the virtual synchronous generator, and combine the two to obtain the active power outer loop of the virtual synchronous generator, and then obtain the amplitude reference and frequency reference of the virtual excitation voltage, such as Figure 5 , Figure 6 The specific expression is shown in formula (4):

[0046]

[0047] Where: J is the virtual inertia corresponding to the virtual rotor, D is the damping coefficient, δ is the virtual power angle, ω is the angular frequency output by the virtual synchronous generator, ω0 is the rated angular frequency of the power grid, E is the amplitude of the virtual internal potential voltage of the VSG, and K is q is the virtual exciter droop control coefficient, U n , U are the rated value and actual value of the virtual stator voltage of VSG, respectively, P m , Q ref is the VSG power given value, which is given by the upper dispatch control layer. k is the integral coefficient, which is used to achieve error-free tracking of reactive power by the VSG system.

[0048] The Phillips-Heffron model of VSG is derived based on active power control, such as Figure 7As shown in Figure 2, the transient output characteristics of VSG are analyzed through this model, and the design principle of virtual inertia is obtained.

[0049] Step S3, taking the output frequency of the virtual synchronous generator as the first control target, making a first adaptive adjustment to the virtual inertia, and then taking the supercapacitor charge state as the second control target, making a second adjustment to the virtual inertia, and correcting the active power outer loop of the virtual synchronous generator in step S2 to obtain the virtual excitation voltage. Figure 1 As shown, it includes the following processes:

[0050] A1: Real-time acquisition of the angular acceleration and angular velocity changes of virtual synchronous generation during transient processes;

[0051] A2: Determine whether the virtual rotor is performing an accelerating motion with an absolute value of angular acceleration greater than a threshold value T; T is a very small value set manually to prevent some small errors from causing frequent fluctuations in the algorithm during operation. In this embodiment, the value of T is 1;

[0052] A3: Adaptively control the virtual inertia of the virtual synchronous generator according to the judgment result in process A2. If the judgment is yes, the virtual inertia should be adaptively increased to prevent the angular velocity from deviating too much, as shown in equations (5) and (6);

[0053] A4 obtains the charge state of the supercapacitor in real time, determines whether the charge state exceeds the upper and lower limit thresholds and whether it is in overcharging or discharging; in this embodiment, the upper and lower limit thresholds (A, B) of the charge state are set manually, which determines the sensitivity of the secondary adjustment. In this embodiment, A takes a value of 20% and B takes a value of 80%.

[0054] A5: Perform secondary adaptive correction on the virtual inertia of the virtual synchronous generator according to the judgment result in step A4. If the judgment result is that the charge state of the supercapacitor is close to the upper and lower limit thresholds, a certain inertia support capacity should be sacrificed to avoid overcharging or overdischarging of the supercapacitor and damage to the equipment. If the judgment result is that the supercapacitor is already in the state of overcharging or overdischarging, the virtual inertia of the VSG is adjusted to zero. At this time, the VSG will be converted into droop control, as shown in equations (7) and (8).

[0055] J tra =J0+J adapt (5)

[0056]

[0057] J sec =n1·J tra (7)

[0058]

[0059] Where: J0 is the value of the system in steady state, T is the angular acceleration threshold, k j , k f is the traditional adaptive adjustment coefficient of virtual inertia, n1 is the secondary correction coefficient of virtual inertia, k1 and k2 are the correction adjustment coefficients of virtual inertia, J tra and J sec are the virtual inertia obtained in steps A3 and A5, SOC sc is the supercapacitor charge state. When SOC sc Higher than SOC max When SOC sc Below SOC min When SOC sc When in the interval (A, B), the supercapacitor has a large charge and discharge margin, and no secondary correction of virtual inertia is performed.

[0060] Step S4, convert the virtual excitation voltage into a modulation voltage through the virtual impedance environment and the voltage-current double closed loop, perform PWM modulation on the obtained modulation voltage, control the inverter to track the given voltage to achieve the inverter to adjust the grid frequency and voltage, thereby achieving the virtual synchronous generator inertia adaptive control, which can control the inverter to track the given voltage and achieve the inverter to adjust the grid frequency and voltage. The main circuit topology diagram of the virtual synchronous generator based on hybrid energy storage on the DC side is shown in Figure 2 shown.

[0061] In order to make the designed virtual synchronous generator control strategy have the electrical characteristics of the synchronous motor stator, a virtual impedance control strategy is introduced. The excitation voltage obtained in step 5 is divided by the virtual impedance to obtain the final voltage reference, such as Figure 8 As shown, the specific expression is shown in formula (9); the voltage reference value obtained by the virtual impedance can be directly used as the modulation signal of SPWM. Although the synchronous machine characteristics can be simulated at this time, the dynamic characteristics are poor and the grid-connected power quality cannot be guaranteed. Therefore, it is necessary to add an inner loop controller to improve the power quality of the virtual synchronous generator output, such as Fig. 9 As shown in Equation (10), since the bandwidth of the inner loop is much larger than that of the power outer loop, the dynamics of the inner loop is often ignored during transient processes.

[0062]

[0063] Where: r v , L v is the virtual impedance, u dref 、u qref The virtual synchronous generator output reference voltage, u d 、u q is the voltage component of the inverter output in the synchronous rotating coordinate system.

[0064] Embodiment 2

[0065] In this embodiment, an electronic device is provided, at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions that can be executed by at least one processor, and the instructions are executed by at least one processor so that the at least one processor can execute the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in the above-mentioned embodiment 1.

[0066] Electronic devices may include processing devices (e.g., central processing units, graphics processing units, etc.), which may perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) or programs loaded from a storage device into a random access memory (RAM). In RAM, various programs and data required for the operation of the electronic device are also stored. The processing device, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0067] Typically, the following systems can be connected to the I / O interface: input devices including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices including, for example, a magnetic tape, a hard disk, etc.; and communication devices. The communication device can allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows an electronic device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0068] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device, or installed from a ROM. When the computer program is executed by a processing device, the above-mentioned functions defined in the method of the embodiment of the present disclosure are executed.

[0069] The electronic device provided by the present invention adopts the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in the above-mentioned embodiment 1. Compared with the prior art, the beneficial effects of the electronic device provided by the embodiment of the present invention are the same as the beneficial effects of the virtual synchronous generator inertia adaptive control method based on hybrid energy storage provided by the above-mentioned embodiment 1, and other technical features in the electronic device are the same as the features disclosed in the method of embodiment 1, which will not be repeated here.

[0070] It should be understood that the various parts of the present disclosure can be implemented with hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0071] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0072] Embodiment 3

[0073] An embodiment of the present invention provides a readable storage medium, which is a computer-readable storage medium. The computer-readable storage medium has computer-readable program instructions stored thereon, and the computer-readable program instructions are used to execute the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in the above-mentioned embodiment 1.

[0074] The present invention also provides a computer-readable storage medium, which may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including, but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof.

[0075] The above-mentioned computer-readable storage medium may be contained in an electronic device; or it may exist independently without being assembled into an electronic device. The computer program code for performing the operation of the present disclosure may be written in one or more programming languages ​​or a combination thereof, and the above-mentioned programming languages ​​include object-oriented programming languages, such as Java, Smalltalk, C++, and also conventional procedural programming languages, such as "C" language or similar programming languages. The program code may be executed entirely on the computer of the person to be detected, partially on the computer of the person to be detected, as an independent software package, partially on the computer of the person to be detected and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the computer of the person to be detected through any type of network, including a local area network (LAN) or a wide area network (WAN), or it may be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0076] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0077] The modules involved in the embodiments described in the present disclosure may be implemented by software or hardware, wherein the name of the module does not limit the unit itself in some cases.

[0078] The computer-readable storage medium provided by the present invention stores computer-readable program instructions for executing the above-mentioned virtual synchronous generator inertia adaptive control method based on hybrid energy storage. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the embodiment of the present invention are the same as the beneficial effects of the virtual synchronous generator inertia adaptive control method based on hybrid energy storage provided by the above-mentioned embodiment 1, and are not described in detail here.

[0079] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the above-mentioned method for adaptive control of inertia of a virtual synchronous generator based on hybrid energy storage are implemented.

[0080] Compared with the prior art, the computer program product provided in the present application has the same beneficial effects as the method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage provided in the above-mentioned embodiment 1, and will not be elaborated here.

[0081] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0082] In addition, those skilled in the art will understand that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments also means being within the scope of protection of the present invention and forming different embodiments. For example, in the above embodiments, those skilled in the art can use them in combination according to the known technical solutions and the technical problems to be solved by this application.

[0083] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A hybrid energy storage virtual synchronous generator inertia adaptive control method, collecting the three-phase voltage and three-phase current signals output by the virtual synchronous generator AC side, calculating the output power of the virtual synchronous generator, characterized in that: The following steps are also included: S1: A filter is used to distribute the output power of the virtual synchronous generator, and the power is separated by frequency, where the low-frequency power is responded by the battery and the high-frequency power is responded by the supercapacitor. Then, a current single closed-loop control method is adopted to achieve the tracking of the battery and the supercapacitor to their respective reference powers. S2: construct a virtual rotor mechanical model and a virtual excitation regulator model of the virtual synchronous generator, and combine the two to obtain the active power outer loop of the virtual synchronous generator, and then obtain the amplitude reference and frequency reference of the virtual excitation voltage; S3: Taking the output frequency of the virtual synchronous generator as the first control target, the virtual inertia is adaptively adjusted for the first time, and then taking the supercapacitor charge state as the second control target, the size of the virtual inertia is adjusted for the second time, and the active power outer loop of the virtual synchronous generator in step S2 is corrected to obtain the virtual excitation voltage; S4: The virtual excitation voltage is converted into a modulation voltage through a virtual impedance environment and a voltage-current double closed loop, and the obtained modulation voltage is PWM modulated to control the inverter to track the given voltage so as to achieve the inverter's regulation of the grid frequency and voltage, thereby realizing the virtual synchronous generator inertia adaptive control.

2. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 1 is characterized in that: In step S1, the output power is calculated based on the instantaneous power theory using the following relationship: Where: P e is the active power output by the inverter, u a ,u b ,u c is the three-phase voltage output by the inverter, i a ,i b ,i c is the three-phase current output by the inverter, Q e It is the reactive power output by the inverter.

3. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 2 is characterized in that: The output power distribution in step S1 specifically includes: using a low-pass filter to decompose the output power of the virtual synchronous generator, and then adopting a current single closed-loop control method to achieve the tracking of the battery and the supercapacitor to their respective reference powers, so that the battery responds to the low-frequency power in the output power of the virtual synchronous generator, and the supercapacitor responds to the high-frequency power in the output power of the virtual synchronous generator. The specific calculation is shown in the following formula: Where τ is the time constant of the low-pass filter, P e is the active power output by the inverter, P b_ref is the reference power of the battery, P sc_ref is the reference power of the supercapacitor, and s represents the continuous domain.

4. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 1 is characterized in that: In step S1, a current single closed-loop control method is adopted to realize the tracking of the battery and the supercapacitor to their respective reference powers, as shown in the following formula: In the formula, i bat is the battery port output current, i bat_ref is the battery port output current reference, i sc is the output current of the supercapacitor port, i bat_ref It is the output current reference of the super capacitor port.

5. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 3 is characterized in that: The virtual rotor mechanical model and the virtual excitation regulator model are shown in the following equations: In the formula: is the virtual inertia corresponding to the virtual rotor, is the damping coefficient, is the virtual power angle, is the angular frequency output by the virtual synchronous generator, is the rated angular frequency of the power grid, is the voltage amplitude of the virtual internal potential of the VSG, Kq is the virtual exciter droop control coefficient, and are the rated value and actual value of the VSG virtual stator voltage respectively, and are the VSG power given value, and K is the integral coefficient, which is used to realize error-free tracking of reactive power by the VSG system.

6. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 1 is characterized in that: Step S5 includes: A1: Real-time acquisition of the angular acceleration and angular velocity changes of the virtual synchronous generator during the transient process; A2: Determine whether the virtual rotor is performing an acceleration motion with an absolute value of angular acceleration greater than an angular acceleration threshold T, where T is a set value; A3: Adaptively control the virtual inertia of the virtual synchronous generator according to the judgment result in step A2. If the judgment is yes, the virtual inertia is adaptively increased. If the judgment is no, no processing is performed. A4: Obtain the charge state of the supercapacitor in real time, determine whether the charge state exceeds the upper and lower limit thresholds and whether it is in an overcharge or overdischarge state. The upper and lower limit thresholds are set values; A5: According to the judgment result in step A4, a correction coefficient is set to perform a secondary adaptive correction on the virtual inertia of the virtual synchronous generator according to the charge state of the supercapacitor.

7. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 6 is characterized in that: The method for adaptively increasing the virtual inertia in step A3 is shown in the following formula: <h2 style=";text-align:left;direction:ltr">J<h2 style=";text-align:left;direction:ltr"> tra <h2 style=";text-align:left;direction:ltr"> =J0+J<h2 style=";text-align:left;direction:ltr"> adapt <h2 style=";text-align:left;direction:ltr"> (5) Where: J0 is the value of the system in steady state, T is the angular acceleration threshold, k j , k f is the traditional adaptive adjustment coefficient of virtual inertia, J tra is the size of the virtual inertia of an adaptive correction, f is the VSG output frequency, and △f is the VSG output frequency deviation.

8. The method for adaptive inertia control of a virtual synchronous generator with hybrid energy storage according to claim 7 is characterized in that: The method for performing secondary adaptive correction on the virtual inertia of the virtual synchronous generator in step A5 is shown in the following formula: I sec =n1·J tra (7) In the formula, J sec is the size of the virtual inertia corrected by the secondary adaptive correction, n1 is the virtual inertia secondary correction coefficient, k1 and k2 are the virtual inertia correction adjustment coefficients, SOC sc is the state of charge of the supercapacitor; A and B are the upper and lower thresholds set manually. sc When it is between the interval (A, B), the virtual inertia of the virtual synchronous generator is not corrected.

9. A hybrid energy storage virtual synchronous generator inertia adaptive control system, used to implement the method according to any one of claims 1 to 8, characterized in that: include: Acquisition module, current single closed-loop control module, active power outer-loop control module, correction module, modulation module; The acquisition module is used to acquire the three-phase voltage and three-phase current signals outputted by the AC side of the virtual synchronous generator and calculate the output power of the virtual synchronous generator; The current single closed-loop control module is used to distribute the output power of the virtual synchronous generator using a filter, and separate the power according to the frequency, where the low-frequency power is responded by the battery and the high-frequency power is responded by the supercapacitor. Then, the current single closed-loop control method is adopted to realize the tracking of the battery and the supercapacitor to their respective reference powers; The active power outer loop control module is used to construct a virtual rotor mechanical model and a virtual excitation regulator model of the virtual synchronous generator. The two are combined to obtain the active power outer loop of the virtual synchronous generator, and then the amplitude reference and frequency reference of the virtual excitation voltage are obtained; A correction module is used to perform a first adaptive adjustment on the virtual inertia with the output frequency of the virtual synchronous generator as the first control target, and then adjust the size of the virtual inertia for the second time with the supercapacitor charge state as the second control target, and correct the active power outer loop of the virtual synchronous generator to obtain a virtual excitation voltage; The modulation module is used to convert the virtual excitation voltage into a modulation voltage through a virtual impedance environment and a voltage-current double closed loop, perform PWM modulation on the obtained modulation voltage, and control the inverter to track the given voltage to achieve the inverter's regulation of the grid frequency and voltage, thereby realizing the virtual synchronous generator inertia adaptive control.

10. An electronic device, characterized in that The electronic device includes: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores commands executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the steps of a virtual synchronous generator inertia adaptive control method based on hybrid energy storage as described in any one of claims 1 to 8.

11. A readable storage medium, characterized in that: The readable storage medium is a computer-readable storage medium, and a program for implementing a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage is stored on the computer-readable storage medium. The program for implementing a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage is executed by a processor to implement the steps of a method for adaptively controlling the inertia of a virtual synchronous generator based on hybrid energy storage as described in any one of claims 1-8.

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