Inertia adaptive control method and system for hybrid energy storage virtual synchronous generator

Abstract

This invention discloses an adaptive control method for the inertia of a virtual synchronous generator based on hybrid energy storage, comprising: acquiring the three-phase voltage and three-phase current signals output from the AC side of the virtual synchronous generator; 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; constructing a Phillips-Heffron model of the virtual synchronous generator to obtain the design principle of the virtual inertia; performing traditional adaptive adjustment of the virtual inertia with the output frequency of the virtual synchronous generator as the control target; and, based on this, adjusting the magnitude of the virtual inertia a second time with the state of charge of the supercapacitor as the control target; converting the virtual inertia into a modulation voltage through a virtual impedance environment and a voltage-current double closed loop; and performing PWM modulation on the obtained modulation voltage to control the inverter to track the given voltage, thereby realizing the inverter's regulation of the grid frequency and voltage.

Description

Technical Field

[0001] This invention relates to virtual synchronous generator control technology, specifically a virtual synchronous generator inertia adaptive control method based on hybrid energy storage. Background Technology

[0002] To meet the growing global energy demand and reduce greenhouse gas emissions, renewable energy has been widely integrated into modern power systems. As the proportion of synchronous generators continues to decline, the system will exhibit low inertia characteristics. To enable renewable energy generation to have a certain inertia support capability, Virtual Synchronous Generator (VSG) control technology can be introduced into the control of power electronic converters to simulate the rotor external characteristics of synchronous generators in the form of algorithms. However, unlike synchronous generators, power electronic converters do not have physical rotors and cannot absorb / generate any energy, which requires additional energy devices to simulate the rotor kinetic energy of synchronous generators. Since distributed generation, such as wind power and photovoltaic power generation, often adopts maximum power point tracking control strategies and lacks power regulation capabilities, energy storage devices with flexible power regulation are often configured on the DC side for power regulation. In existing technologies, energy storage devices employ a hybrid of batteries and supercapacitors. Supercapacitors, characterized by high power density and low energy density, can be used to provide the high-frequency power required by the VSG (Vehicle Stability Generator), simulating the power change of the synchronous generator rotor kinetic energy during transient processes and providing inertia support to the system. Batteries, with their high energy density and low power density, can be used to provide the low-frequency power required by the VSG, simulating the power provided by the synchronous generator prime mover and providing steady-state power support to the system. High-pass / low-pass filters are widely used in engineering to achieve a reasonable distribution of high and low-frequency power.

[0003] During normal grid-connected operation, VSGs inevitably experience disturbances from themselves and the system, including changes in VSG power commands and grid frequency fluctuations. Under these disturbances, the VSG output voltage and power will oscillate. However, as a power electronic device, the VSG's ability to withstand power surges and frequency oscillations is far less than that of a traditional synchronous generator. To optimize the transient output characteristics of the VSG, a VSG inertia adaptive strategy is proposed. This strategy adaptively adjusts the virtual inertia based on the VSG's output angular frequency and angular acceleration, thereby optimizing the VSG's transient output characteristics.

[0004] When performing parameter adaptive design on virtual synchronous generators, the DC side is often equated to an infinite constant voltage source, reducing the engineering practicality of VSG control technology. Furthermore, neglecting the physical constraints of the DC side may lead to overcharging and over-discharging of the energy storage device, reducing its lifespan. This is especially true for supercapacitors with low energy density, as the virtual kinetic energy used to provide the virtual rotor changes frequently during transient processes, making them highly susceptible to overcharging and over-discharging, which is detrimental to the safe and stable operation of the system. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a VSG inertia adaptive control method based on hybrid energy storage.

[0006] The technical solution adopted in this invention is: an adaptive control method for the inertia of a virtual synchronous generator based on hybrid energy storage, which involves acquiring the three-phase voltage and three-phase current signals output from the AC side of the virtual synchronous generator and calculating the output power of the virtual synchronous generator. The method further includes the following steps:

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

[0008] S2: Construct a virtual rotor mechanical model and a virtual excitation regulator model for a virtual synchronous generator. 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: Using the output frequency of the virtual synchronous generator as the first control target, the virtual inertia is adaptively adjusted for the first time. Then, using the state of charge of the supercapacitor as the second control target, the magnitude of the virtual inertia is adjusted for the second time. This corrects the active power outer loop of the virtual synchronous generator in step S2, resulting in the virtual excitation voltage. Specifically, this includes:

[0010] A1: Real-time acquisition of the angular acceleration and angular velocity changes of the virtual synchronous generator during transient processes;

[0011] A2: Determine whether the virtual rotor is undergoing accelerated motion with an absolute value of angular acceleration greater than the angular acceleration threshold T, where T is a set value;

[0012] A3: Based on the judgment result in step A2, adaptive control is performed on the virtual inertia of the virtual synchronous generator. If the judgment is yes, the virtual inertia is adaptively increased; if the judgment is no, no action is taken.

[0013] A4: Real-time acquisition of the state of charge of the supercapacitor, determining whether the state of charge exceeds the upper and lower thresholds and whether it is in an overcharged or over-discharged state. The upper and lower thresholds are set values.

[0014] A5: Based on the judgment result in step A4, the virtual inertia of the virtual synchronous generator is adaptively corrected a second time according to the magnitude of the supercapacitor's state of charge by setting a correction coefficient.

[0015] S4: The virtual excitation voltage is converted into a modulation voltage through a virtual impedance environment and a voltage and current double closed loop. The obtained modulation voltage is PWM modulated to control the inverter to track the given voltage so as to realize the inverter's regulation of the grid frequency and voltage, thereby realizing the virtual synchronous generator inertia adaptive control.

[0016] An 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, the commands being executed by the at least one processor to enable the at least one processor to perform the steps of the above-described method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage.

[0017] A readable storage medium, wherein the readable storage medium is a computer-readable storage medium, and the computer-readable storage medium stores a program implementing a method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage, wherein the program implementing the method for adaptive inertia control 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 adaptive inertia control of a virtual synchronous generator based on hybrid energy storage.

[0018] The beneficial effects of this invention are:

[0019] (1) Considering that the DC side is a hybrid energy storage system, this invention, in order to fully utilize the high power density of supercapacitors, decomposes the power through a filter and allocates the high-frequency inertia support power corresponding to the virtual inertia to the supercapacitors. Therefore, the magnitude of the virtual inertia will directly affect the charging and discharging power and state of charge of the supercapacitors during transient processes. Analysis shows that the maximum value of the change in the state of charge of the supercapacitors during transient processes is proportional to the virtual inertia. In the adaptive control of virtual inertia, this invention takes into account the state of charge of the supercapacitors, which can prevent the supercapacitors from overcharging and over-discharging during transient processes and improve the dynamic characteristics of the output of the virtual synchronous generator during transient processes.

[0020] (2) The inertia adaptive control strategy proposed in this 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.

[0021] (3) The inertia adaptive control strategy proposed in this invention can provide a certain steady-state power support and transient inertia support to the system by reasonably allocating power to the hybrid energy storage device of supercapacitor and battery while ensuring that the supercapacitor does not overcharge or over-discharge. Attached Figure Description

[0022] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0023] In the attached diagram:

[0024] Figure 1 This is a flowchart of the method for secondary adjustment of virtual inertia in an embodiment of the present invention;

[0025] Figure 2 This is the main circuit topology diagram of a virtual synchronous generator based on hybrid energy storage on the DC side;

[0026] Figure 3 This is a block diagram of DC-side hybrid energy storage power distribution control;

[0027] Figure 4 This is the inner loop control block diagram of the DC-side hybrid energy storage;

[0028] Figure 5 This is a block diagram of the active power control of a virtual synchronous generator;

[0029] Figure 6 This is a block diagram of reactive power control for a virtual synchronous generator;

[0030] Figure 7 This is a Phillips-Heffron model diagram of a virtual synchronous generator;

[0031] Figure 8 This is a block diagram of virtual impedance control for a virtual synchronous generator;

[0032] Figure 9 This is the inner loop control block diagram of the virtual synchronous generator.

[0033] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0034] To make the objectives, 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 with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0035] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Explanation of the meanings of terms used in the instruction manual:

[0038] Virtual Synchronous Generator (VSG): Through control strategies, the grid-connected inverter simulates the operating mechanism of a synchronous generator and participates in the frequency and voltage regulation of the power grid.

[0039] State of charge (SOC): SOC is a physical quantity that reflects the remaining capacity of an energy storage unit. A value that is too high or too low will affect the charging and discharging performance and lifespan of the energy storage battery.

[0040] Example 1

[0041] Step S1: Calculate the output power of the virtual synchronous generator. First, the signals of the three-phase voltage and three-phase current output from the AC side of the virtual synchronous generator are collected in real time. The output power is calculated using instantaneous power theory, as shown in Equation (1):

[0042] { P e = u a ⋅ i a + u b ⋅ i b + u c ⋅ i c Q e = 1 3 [ ( u a − u b ) ⋅ i c + ( u b − u c ) ⋅ i a + ( u a − u c ) ⋅ i b ]

[0043] In the formula: P e u is the active power output of the inverter. a u b u c i is the output voltage of the inverter (filter capacitor voltage). a i bi c This is the output current of the inverter (the filtered current).

[0044] It should be noted that the power calculated using instantaneous power theory in this embodiment often contains high-order harmonics, requiring filtering with a low-pass filter, such as... Figure 5 , Figure 6 As shown.

[0045] A low-pass filter is used to decompose the output power of the virtual synchronous generator, separating the power according to frequency. Low-frequency power is responded to by the battery, and high-frequency power by the supercapacitor, thus achieving power distribution between the battery and supercapacitor. Specifically, the battery responds to the low-frequency power of the virtual synchronous generator's output power, simulating the prime mover in the synchronous generator and providing steady-state power support to the system. The supercapacitor responds to the high-frequency power of the virtual synchronous generator's output power, simulating the rotor kinetic energy in the synchronous generator and providing transient inertia support to the system. In steady state, this power is zero, meaning the supercapacitor output is zero. The DC-side hybrid energy storage power distribution control block diagram is shown below. Figure 3 As shown, the specific expression is as shown in equation (2):

[0046]

[0047] In the formula: τ is the time constant of the low-pass filter.

[0048] Then, a single closed-loop current control method is adopted to achieve tracking of the reference power of the battery and the supercapacitor, such as... Figure 4 As shown in Equation 3, since the bandwidth of the inner loop is much larger than that of the power outer loop, the dynamics of the inner loop are often ignored during transient processes.

[0049]

[0050] Step S2 involves constructing a virtual rotor mechanical model and a virtual excitation regulator model for the virtual synchronous generator. Combining these two models yields the active power outer loop of the virtual synchronous generator, which in turn provides the amplitude and frequency references for the virtual excitation voltage. Figure 5 , Figure 6 As shown, the specific expression is as shown in equation (4):

[0051]

[0052] In the formula: 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 of the virtual synchronous generator output, ω0 is the rated angular frequency of the power grid, E is the amplitude of the virtual internal electromotive force voltage of the VSG, and K q U is the droop control coefficient for the virtual exciter.n U and P are the rated and actual values ​​of the VSG virtual stator voltage, respectively. m Q ref The VSG power setpoint is given by the higher-level dispatch control layer. k is the integral coefficient, used to achieve error-free tracking of reactive power by the VSG system.

[0053] The Phillips-Heffron model of VSG is derived based on active power control, such as... Figure 7 As shown in the figure. By analyzing the transient output characteristics of VSG through this model, the design principles of virtual inertia are obtained.

[0054] Step S3 involves first adaptively adjusting the virtual inertia using the output frequency of the virtual synchronous generator as the first control target, and then adjusting the virtual inertia a second time using the supercapacitor's state of charge as the second control target. This corrects the active power outer loop of the virtual synchronous generator from step S2, resulting in the virtual excitation voltage. Figure 1 As shown, the process includes the following:

[0055] A1: Real-time acquisition of angular acceleration and angular velocity changes during the transient process of virtual synchronous power generation;

[0056] A2: Determine whether the virtual rotor is undergoing accelerated motion with an absolute value of angular acceleration greater than the threshold T; T is a very small value set manually to prevent small errors from causing frequent fluctuations in the algorithm during operation. In this embodiment, T is set to 1.

[0057] A3: Based on the judgment result in process A2, the virtual inertia of the virtual synchronous generator is adaptively controlled. 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).

[0058] A4 acquires the state of charge of the supercapacitor in real time and determines whether the state of charge exceeds the upper and lower thresholds and whether it is overcharged or discharged. In this embodiment, the upper and lower thresholds of the state of charge (A, B) are set manually, which determines the sensitivity of the secondary adjustment. In this embodiment, A is 20% and B is 80%.

[0059] A5: Based on the judgment result in step A4, the virtual inertia of the virtual synchronous generator is adaptively corrected for the second time. If the judgment result is that the state of charge of the supercapacitor is close to the upper and lower limit thresholds, a certain amount of inertia support capacity should be sacrificed to avoid overcharging and over-discharging of the supercapacitor, which would harm the equipment. If the judgment result is that the supercapacitor is already overcharged or over-discharged, 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).

[0060]

[0061]

[0062]

[0063]

[0064] In the formula: J0 is the value of the system in steady state, J adapt For adaptive virtual inertia, T is the angular acceleration threshold, and k j k f J represents the traditional adaptive adjustment coefficient for virtual inertia, n1 represents the secondary correction coefficient for virtual inertia, and k1 and k2 represent the correction adjustment coefficients for virtual inertia. tra and J sec The magnitudes of the virtual inertia obtained in steps A3 and A5 are respectively, and the SOC is... sc The state of charge (SOC) of a supercapacitor is... sc Higher than SOC max At that time, the supercapacitor is in an overcharged state; when the SOC (State of Charge) is reached... sc Below SOC min At that time, the supercapacitor is in an over-discharged state; when the SOC (State of Charge) is reached... sc When the supercapacitor is in the range (A, B), it has a large charge and discharge margin and does not require secondary correction of virtual inertia.

[0065] Step S4: The virtual excitation voltage is converted into a modulation voltage through a virtual impedance environment and a voltage-current double-closed loop. The obtained modulation voltage is then subjected to PWM modulation to control the inverter to track the given voltage, thereby achieving inverter regulation of grid frequency and voltage. This realizes adaptive inertia control of the virtual synchronous generator, enabling the inverter to track the given voltage and regulate grid frequency and voltage. The DC-side main circuit topology of the virtual synchronous generator based on hybrid energy storage is shown below. Figure 2 As shown.

[0066] To ensure the designed virtual synchronous generator control strategy possesses the stator electrical characteristics of a synchronous motor, a virtual impedance control strategy is introduced. The excitation voltage obtained in step 5 is then divided by the virtual impedance to obtain the final voltage reference, such as... Figure 8 As shown, the specific expression is shown in equation (9); the voltage reference value obtained through the virtual impedance can be directly used as the modulation signal of SPWM. Although it can simulate the characteristics of a synchronous machine, 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 output of the virtual synchronous generator, such as Figure 9As 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 are often ignored during transient processes.

[0067]

[0068]

[0069] In the formula: , For virtual impedance, , The virtual synchronous generator outputs a reference voltage. , This refers to the voltage component output by the inverter in a synchronous rotating coordinate system.

[0070] Example 2

[0071] This embodiment provides an electronic device, at least one processor, and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to execute the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in Embodiment 1 above.

[0072] Electronic devices may include processing units (such as central processing units, graphics processing units, etc.) that can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) or programs loaded from storage devices into random access memory (RAM). RAM also stores various programs and data required for the operation of the electronic device. The processing unit, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0073] Typically, the following systems can be connected to the I / O interface: input devices including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices including, for example, magnetic tapes, hard disks, etc.; and communication devices. Communication devices allow electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although electronic devices with various systems are shown in the figures, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems may be implemented alternatively.

[0074] In particular, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device, or installed from a ROM. When the computer program is executed by a processing device, it performs the functions defined above in the methods of embodiments of this disclosure.

[0075] The electronic device provided by the present invention adopts the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in Embodiment 1 above. Compared with the prior art, the beneficial effects of the electronic device provided by the present invention are the same as those of the virtual synchronous generator inertia adaptive control method based on hybrid energy storage provided in Embodiment 1 above. Moreover, other technical features of the electronic device are the same as those disclosed in the method of Embodiment 1, and will not be repeated here.

[0076] It should be understood that various parts of this disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0077] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0078] Example 3

[0079] This invention provides a readable storage medium, which is a computer-readable storage medium having computer-readable program instructions stored thereon. The computer-readable program instructions are used to execute the virtual synchronous generator inertia adaptive control method based on hybrid energy storage in Embodiment 1 above.

[0080] This invention also provides a computer-readable storage medium, such as a USB flash drive, but not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium can be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof.

[0081] The aforementioned computer-readable storage medium may be included in an electronic device or may exist independently, not assembled into an electronic device. Computer program code for performing the operations of this disclosure may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code may be executed entirely on the computer of the person being detected, partially on the computer of the person being detected, as a stand-alone software package, partially on the computer of the person being detected 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 computer of the person being detected 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).

[0082] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0083] The modules described in the embodiments of this disclosure can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0084] The computer-readable storage medium provided by this invention stores computer-readable program instructions for executing the above-described adaptive inertia control method for a virtual synchronous generator based on hybrid energy storage. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this embodiment are the same as those of the adaptive inertia control method for a virtual synchronous generator based on hybrid energy storage provided in Embodiment 1 above, and will not be repeated here.

[0085] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage.

[0086] Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the virtual synchronous generator inertia adaptive control method based on hybrid energy storage provided in Embodiment 1 above, and will not be repeated here.

[0087] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0088] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A hybrid energy storage virtual synchronous generator inertia adaptive control method, comprising acquiring the three-phase voltage and three-phase current signals output from 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: S1: The output power of the virtual synchronous generator is distributed by a filter, and the power is separated by frequency. The low-frequency power is responded to by the battery and the high-frequency power is responded to by the supercapacitor. Then, a single closed-loop current control method is adopted to realize the tracking of the battery and the supercapacitor to their respective reference power. S2: Construct a virtual rotor mechanical model and a virtual excitation regulator model for a virtual synchronous generator. 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: Using the output frequency of the virtual synchronous generator as the first control target, the virtual inertia is adaptively adjusted for the first time. Then, using the state of charge of the supercapacitor as the second control target, the magnitude of the virtual inertia is adjusted for the second time. This corrects the active power outer loop of the virtual synchronous generator in step S2, resulting in the virtual excitation voltage. Specifically, this includes: A1: Real-time acquisition of the angular acceleration and angular velocity changes of the virtual synchronous generator during transient processes; A2: Determine whether the virtual rotor is undergoing accelerated motion with an absolute value of angular acceleration greater than the angular acceleration threshold T, where T is a set value; A3: Based on the judgment result in step A2, adaptive control is performed on the virtual inertia of the virtual synchronous generator. If the judgment is yes, the virtual inertia is adaptively increased; if the judgment is no, no action is taken. A4: Real-time acquisition of the state of charge of the supercapacitor, determining whether the state of charge exceeds the upper and lower thresholds and whether it is in an overcharged or over-discharged state. The upper and lower thresholds are set values. A5: Based on the judgment result in step A4, the virtual inertia of the virtual synchronous generator is adaptively corrected a second time according to the magnitude of the supercapacitor's state of charge by setting a correction coefficient. S4: The virtual excitation voltage is converted into a modulation voltage through a virtual impedance environment and a voltage and current double closed loop. The obtained modulation voltage is PWM modulated to control the inverter to track the given voltage so as to realize the inverter's regulation of the grid frequency and voltage, thereby realizing the virtual synchronous generator inertia adaptive control.

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

3. The virtual synchronous generator inertia adaptive control method for hybrid energy storage according to claim 2, characterized in that: Step S1, which involves allocating the output power, specifically includes: decomposing the output power of the virtual synchronous generator using a low-pass filter, and then employing a current-based single-loop control method to achieve tracking of the battery and supercapacitor against their respective reference power. This ensures that the battery responds to the low-frequency power in the output power of the virtual synchronous generator, while the supercapacitor responds to the high-frequency power. The specific calculation is shown in the following formula: （2） In the formula, τ is the time constant of the low-pass filter, and P e P represents the active power output of the inverter. b_ref P is the reference power of the battery. sc_ref is the reference power of the supercapacitor, and s represents the continuous domain.

4. The virtual synchronous generator inertia adaptive control method for hybrid energy storage according to claim 1, characterized in that: In step S1, a single closed-loop current control method is adopted to achieve tracking of the reference power of the battery and the supercapacitor, as shown in the following formula: （3） In the formula, i bat i is the output current at the battery port. bat_ref i serves as the reference for the battery's port output current. sc i is the port output current of the supercapacitor. bat_ref This serves as a reference for the port output current of the supercapacitor.

5. The virtual synchronous generator inertia adaptive control method for hybrid energy storage according to claim 3, characterized in that: The virtual rotor mechanical model and the virtual excitation regulator model are shown in the following equations: （4） In the formula: 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 of the virtual synchronous generator output, ω0 is the rated angular frequency of the power grid, E is the amplitude of the virtual internal electromotive force voltage of the VSG, and K q U is the droop control coefficient for the virtual exciter. n U and P are the rated and actual values ​​of the VSG virtual stator voltage, respectively. m Q ref The given value for VSG power is k, which is the integral coefficient used to achieve error-free tracking of reactive power by the VSG system.

6. The virtual synchronous generator inertia adaptive control method for hybrid energy storage according to claim 1, characterized in that: The method for adaptively increasing the virtual inertia in step A3 is shown in the following formula: （5） （6） In the formula: J0 is the value of the system in steady state, J adapt For adaptive virtual inertia, T is the angular acceleration threshold, and k j k f J is the traditional adaptive adjustment coefficient for virtual inertia. tra The magnitude of the virtual inertia for one adaptive correction. For the VSG output frequency, △ This refers to the VSG output frequency deviation.

7. The virtual synchronous generator inertia adaptive control method for hybrid energy storage according to claim 1, characterized in that: The method for performing a secondary adaptive correction on the virtual inertia of the virtual synchronous generator in step A5 is shown in the following formula: （7） （8） In the formula, J sec The virtual inertia is the magnitude of the second-order adaptive correction, n1 is the second-order correction coefficient of the virtual inertia, k1 and k2 are the virtual inertia correction adjustment coefficients, and SOC is the value of the virtual inertia. sc This refers to the state of charge (SOC) of the supercapacitor; A and B are artificially set upper and lower threshold values. sc When the virtual inertia is between the intervals (A, B), no correction is made to the virtual inertia of the virtual synchronous generator.

8. A hybrid energy storage virtual synchronous generator inertia adaptive control system for implementing the method described in any one of claims 1 to 7, 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 output from 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, separating the power according to frequency. The low-frequency power is responded to by the battery, and the high-frequency power is responded to 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 power. The active power outer loop control module is used to construct the virtual rotor mechanical model and the 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. The correction module is used to perform the first adaptive adjustment of 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 state of charge of the supercapacitor as the second control target, thereby correcting the active power outer loop of the virtual synchronous generator and obtaining the 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 and current double closed loop. The obtained modulation voltage is then subjected to PWM modulation to control the inverter to track the given voltage, thereby realizing the inverter's regulation of the grid frequency and voltage, and thus achieving virtual synchronous generator inertia adaptive control.

9. 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, the commands being executed by the at least one processor to enable the at least one processor to perform the steps of the virtual synchronous generator inertia adaptive control method based on hybrid energy storage as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium is a computer-readable storage medium, and the computer-readable storage medium stores a program that implements a method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage. The program that implements the method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage is executed by a processor to implement the steps of the method for adaptive inertia control of a virtual synchronous generator based on hybrid energy storage as described in any one of claims 1-7.

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