Virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation

Abstract

The invention discloses a virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation. The method comprises the following steps: establishing a control equation of a virtual generator of an energy storage converter; self-adaptive virtual torque and self-adaptive virtual electromotive force compensation quantity are added into the virtual synchronous generator control equation, and an improved virtual synchronous generator control equation based on self-adaptive virtual torque compensation is obtained; calculating to obtain the compensation amount of the adaptive virtual torque and the adaptive virtual electromotive force; in the off-grid mode, the output voltage of the energy storage converter and the voltage of the power grid are input into the self-adaptive virtual torque compensation controller, the compensation amount of the self-adaptive virtual torque and the compensation amount of the self-adaptive virtual electromotive force are output and compensated to a virtual synchronous generator control equation of the energy storage converter, and therefore synchronization of the voltage of the power grid is achieved. The output voltage amplitude and the voltage phase of the converter can be quickly adjusted only by collecting the output voltage of the converter and the voltage of the power grid, and the effect of smooth grid connection of the converter is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronic converters, and in particular relates to a pre-synchronization control method of a virtual synchronous generator based on adaptive virtual torque compensation. Background Art

[0002] With the development of science and technology and the growth of energy demand, coupled with the limitations of traditional fuel resources, unconventional energy (such as wind energy, solar energy, etc.) is increasingly being connected to the distribution network through inverters. Although the grid connection of these new energy sources helps to ease the energy shortage, it also brings new challenges to the stable operation of the power system, such as voltage instability and cascading failures, which in turn affects the anti-interference ability and dynamic response characteristics of the power grid. In order to cope with the challenges brought by multi-source grid connection to the inertia of the power grid, researchers have proposed a virtual synchronous generator (VSG) control strategy as one of the solutions. VSG technology aims to simulate the behavioral characteristics of traditional synchronous generators, especially its rotor motion and excitation control mechanism, to give the renewable energy power generation system certain inertia and damping characteristics, thereby enhancing the stability of the power grid. Converters using VSG control strategies are called grid-connected converters. Such devices can not only regulate voltage and frequency, but also support two working modes: grid-connected and off-grid. In the grid-connected state, they provide the necessary voltage and frequency support for the grid; in the off-grid mode, they can rely on their own control capabilities to independently supply power to form a microgrid environment. When the converter needs to switch between these two modes, the key to ensuring a smooth transition lies in effective pre-synchronization processing.

[0003] Traditional pre-synchronization methods usually rely on phase-locked loops (PLLs) or frequency-locked loops (FLLs) and their derivative technologies to achieve pre-synchronization, which makes the pre-synchronization effect largely depend on the performance of the PLL or FLL. However, under certain specific conditions, the performance of these components may be affected, resulting in a less than ideal pre-synchronization process. In view of this, the present invention proposes a new pre-synchronization control scheme, which does not rely on PLLs or FLLs, but achieves pre-synchronization through a more simplified mechanism, thereby improving the reliability and efficiency of the converter when switching between different operating modes. Summary of the invention

[0004] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation. The present invention does not require a phase-locked loop or a PI controller. It only needs to collect the converter output voltage and the grid voltage to quickly adjust the converter output voltage amplitude and voltage phase, thereby achieving the effect of smooth converter grid connection.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation, comprising the following steps:

[0007] According to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method, the control equation of the virtual generator of the energy storage converter is established;

[0008] An adaptive virtual torque compensation controller is constructed, and adaptive virtual torque and adaptive virtual electromotive force compensation are added to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation.

[0009] The output voltage of the energy storage converter and the grid voltage are used as control quantities, and the compensation quantities of the adaptive virtual torque and the adaptive virtual electromotive force are calculated through the adaptive virtual torque compensation controller;

[0010] In off-grid mode, the output voltage of the energy storage converter and the grid voltage are input into the adaptive virtual torque compensation controller, and the compensation of the adaptive virtual torque and the adaptive virtual electromotive force is output and compensated to the virtual synchronous generator control equation of the energy storage converter, thereby achieving synchronization of the grid voltage.

[0011] As a preferred technical solution, the control equation of the virtual generator is specifically:

[0012]

[0013] Where P ref is the reference active power, Q ref is the reference reactive power, w0 is the reference angular frequency, U n is the effective value of the reference voltage, U n is the reference voltage amplitude, P e is the converter output active power, Q e is the reactive power output by the converter, U is the effective value of the converter output voltage, w is the angular frequency of the converter output voltage, θ is the phase of the converter output voltage, E is the converter terminal voltage, E0 is the rated no-load electromotive force, J is the moment of inertia, D is the damping coefficient, k p is the active power droop coefficient, k q is the reactive power droop coefficient, k i is the integration coefficient.

[0014] As a preferred technical solution, the improved control equation of the virtual synchronous generator based on adaptive virtual torque compensation is specifically:

[0015]

[0016] Where, T comis the adaptive virtual torque compensation, U com is the adaptive virtual electromotive force compensation, S i Indicates the inverter on-grid and off-grid operation state, S i 0 means off-grid, S i 1 indicates grid connection.

[0017] As a preferred technical solution, an adaptive virtual torque compensation controller is designed to obtain an adaptive virtual torque compensation amount and an adaptive virtual electromotive force compensation amount. In a stationary two-axis coordinate system, the converter output voltage and the grid voltage are respectively:

[0018]

[0019] Where V oα and V oβ are the α-axis voltage component and β-axis voltage component output by the converter under the stationary two-phase coordinate axis, V gα and V gβ are the α-axis voltage component and β-axis voltage component of the grid voltage output under the static two-phase coordinate axis, V o and V g are the converter output voltage amplitude and grid voltage amplitude, w0 and w g are the converter output voltage angular frequency and the grid voltage angular frequency, θ o and θ g They are the converter output voltage phase and grid voltage phase respectively.

[0020] As a preferred technical solution, in order to construct the angular frequency and phase relationship between the converter output voltage and the grid voltage, the converter output voltage and the grid voltage in the above-mentioned stationary two-axis coordinate system are cross-multiplied to obtain a first relationship:

[0021] V gα V oβ -V gβ V oα =V o V g sin[(w g -w0)t+(θ g -θ o )]

[0022] When the converter output voltage and grid voltage angular frequency and phase are synchronized, the first relation is obtained:

[0023] V gα V oβ -V gβ V oα =0

[0024] That is, the virtual torque compensation relationship is constructed as:

[0025] T com =h Tcom (V gα V oβ -V gβ V oα )

[0026] In the formula, h Tcom is the virtual torque compensation coefficient;

[0027] According to the difference between the converter output voltage and the grid voltage amplitude, the second relationship is obtained:

[0028]

[0029] When the converter output voltage and grid voltage amplitude are synchronized, the above second relation is obtained:

[0030] V g -V o =0

[0031] That is, the virtual electromotive force compensation relationship is constructed as follows:

[0032]

[0033] In the formula, h Ucom is the virtual electromotive force compensation coefficient.

[0034] As a preferred technical solution, the adaptive rule of the adaptive virtual torque compensation controller is as follows:

[0035]

[0036] In the formula, k iT and K iU are the initial values ​​of virtual torque compensation coefficient and virtual electromotive force compensation coefficient, respectively, rT and k rU They are the virtual torque compensation adjustment coefficient and the virtual electromotive force compensation adjustment coefficient respectively.

[0037] As a preferred technical solution, the synchronization of grid voltage is achieved as follows:

[0038] The voltage sensor collects the three-phase voltage output by the converter and the three-phase voltage of the power grid as the control quantity, which is input into the adaptive virtual torque compensation controller. The virtual torque compensation coefficient and the virtual electromotive force compensation coefficient are calculated in combination with the adaptive rule of the adaptive virtual torque compensation controller. The compensation amounts of the adaptive virtual torque and the adaptive virtual electromotive force are calculated using the virtual torque compensation relationship and the virtual electromotive force compensation relationship. The reference electromotive force and the reference angular frequency are obtained through the control equation of the improved virtual synchronous generator, and then handed over to the voltage and current dual closed-loop control, so that the converter adjusts the output voltage amplitude, angular frequency and phase, so as to achieve synchronization with the power grid voltage.

[0039] In a second aspect, the present invention provides a virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation, comprising a first control equation construction module, a second control equation construction module, a compensation amount calculation module and a grid voltage synchronization module;

[0040] The first control equation building module is used to establish the control equation of the virtual generator of the energy storage converter according to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method;

[0041] The second control equation construction module is used to construct an adaptive virtual torque compensation controller, and add adaptive virtual torque and adaptive virtual electromotive force compensation to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation;

[0042] The compensation amount calculation module is used to use the output voltage of the energy storage converter and the grid voltage as control quantities, and calculate the compensation amounts of the adaptive virtual torque and the adaptive virtual electromotive force through the adaptive virtual torque compensation controller;

[0043] The grid voltage synchronization module is used to input the output voltage of the energy storage converter and the grid voltage into the adaptive virtual torque compensation controller in the off-grid mode, output the compensation amount of the adaptive virtual torque and the adaptive virtual electromotive force, and compensate them to the virtual synchronous generator control equation of the energy storage converter, thereby realizing the synchronization of the grid voltage.

[0044] In a third aspect, the present invention provides an electronic device, the electronic device comprising:

[0045] at least one processor; and,

[0046] a memory communicatively connected to the at least one processor; wherein,

[0047] The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor to enable the at least one processor to perform the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium storing a program, which, when executed by a processor, implements the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] 1. The virtual synchronous generator pre-synchronization control strategy based on adaptive virtual torque compensation proposed in the present invention realizes smooth switching between the grid-connected and off-grid operating states of the converter without adding an additional phase-locked loop or PI controller, and can realize low-cost phase-locked loop-free and PI controller-free control, reduce the algorithm operation complexity, simplify the control algorithm, and reduce the error coupled to the pre-synchronization process due to the phase-locked loop performance.

[0051] 2. The present invention adds adaptive control to virtual torque compensation, and uses an adaptive control function instead of the compensation coefficient to synchronize the converter output voltage with the grid voltage quickly. Even when the converter output voltage amplitude, angular frequency and phase are greatly different from those of the grid, rapid synchronization can be achieved.

[0052] 3. The present invention does not require switching control algorithms when switching between grid and off-grid. During grid-connected and off-grid steady-state operation, the virtual torque compensation and virtual electromotive force compensation are 0, which is an ordinary virtual synchronous generator control strategy. Virtual torque compensation and virtual electromotive force compensation are added only when the converter operates in the pre-synchronization state. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 It is the overall framework of the control system described in the present invention;

[0055] Figure 2 It is a frequency waveform diagram of the pre-synchronization process under different virtual torque compensation coefficients of the present invention;

[0056] Figure 3The waveform diagram of the a-phase voltage output by the converter and the a-phase grid voltage of the present invention;

[0057] Figure 4 The three-phase voltage and current waveform diagram output by the converter of the present invention;

[0058] Figure 5 It is a waveform diagram of output current of the pre-synchronization process converter under different virtual torque compensation coefficients of the present invention;

[0059] Figure 6 The waveform diagram of active power and reactive power output by the converter of the present invention;

[0060] Figure 7 The waveform diagram of active power output by the pre-synchronization process converter under different virtual torque compensation coefficients of the present invention;

[0061] Figure 8 It is a reactive power waveform diagram of the pre-synchronization process converter output under different virtual torque compensation coefficients of the present invention;

[0062] Fig. 9 It is a structural diagram of the pre-synchronization control of the virtual synchronous generator based on adaptive virtual torque compensation of the present invention;

[0063] Fig.10 Schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0065] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0066] like Figure 1 As shown, the overall framework of the control system includes a storage DC source part, a three-phase three-level T-type topology converter part, a three-phase LC filter part, a circuit breaker, an AC power grid, a local load, a virtual synchronous generator control module and a pre-synchronization control module.

[0067] The virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation in this embodiment includes the following steps:

[0068] Step S1, establishing a control equation of a virtual generator of an energy storage converter according to the rotor motion equation and excitation control equation of a synchronous generator and a droop control method.

[0069] Furthermore, in step S1, the control equation of the virtual synchronous generator is:

[0070]

[0071] Where P ref is the reference active power, Q ref is the reference reactive power, w0 is the reference angular frequency, U n is the effective value of the reference voltage, U n is the reference voltage amplitude, P e is the converter output active power, Q e is the reactive power output by the converter, U is the effective value of the converter output voltage, w is the angular frequency of the converter output voltage, θ is the phase of the converter output voltage, E is the converter terminal voltage, E0 is the rated no-load electromotive force, J is the moment of inertia, D is the damping coefficient, k p is the active power droop coefficient, k q is the reactive power droop coefficient, k i is the integration coefficient.

[0072] Step S2, constructing an adaptive virtual torque compensation controller, adding adaptive virtual torque and adaptive virtual electromotive force compensation to the virtual synchronous generator control equation, and obtaining an improved virtual synchronous generator control equation based on adaptive virtual torque compensation.

[0073] Further, in step S2, after adding the adaptive virtual torque compensation and the adaptive virtual electromotive force compensation, the control equation of the virtual synchronous generator is:

[0074]

[0075] Where, T com is the adaptive virtual torque compensation, U com is the adaptive virtual electromotive force compensation, S i Indicates the inverter is in the on-grid and off-grid operating state. i The formula is:

[0076]

[0077] Step S3: using the converter output voltage and the grid voltage as control quantities, and calculating the compensation quantities of the adaptive virtual torque and the adaptive virtual electromotive force through an adaptive virtual torque compensation controller.

[0078] In step S3, an adaptive virtual torque compensation controller is designed to obtain an adaptive virtual torque compensation amount and an adaptive virtual electromotive force compensation amount. Assume that in a stationary two-phase coordinate system, the converter output voltage and the grid voltage are respectively:

[0079]

[0080] Where V oα and V oβ are the α-axis voltage component and β-axis voltage component output by the converter under the stationary two-phase coordinate axis, V gα and V gβ are the α-axis voltage component and β-axis voltage component of the grid voltage output under the static two-phase coordinate axis, V o and V g are the converter output voltage amplitude and grid voltage amplitude, w0 and w g are the converter output voltage angular frequency and the grid voltage angular frequency, θ o and θ g They are the converter output voltage phase and grid voltage phase respectively.

[0081] In step S3, an adaptive virtual torque compensation controller is designed. In order to construct the angular frequency and phase relationship between the converter output voltage and the grid voltage, the converter output voltage and the grid voltage are cross-multiplied in the above-mentioned stationary two-axis coordinate system to obtain:

[0082] V gα V oβ -V gβ V oα =V o V g sin[(w g -w0)t+(θ g -θ o )] (5)

[0083] When the angular frequency and phase of the converter output voltage and the grid voltage are synchronized, the above relationship can be obtained:

[0084] V gα V oβ -V gβ V oα =0 (6)

[0085] That is, the virtual torque compensation relationship is constructed as:

[0086] T com=h Tcom (V gα V oβ -V gβ V oα ) (7)

[0087] In the formula, h Tcom is the virtual torque compensation coefficient.

[0088] According to the difference between the converter output voltage and the grid voltage amplitude, we can get:

[0089]

[0090] When the converter output voltage and grid voltage amplitude are synchronized, the above relationship can be obtained:

[0091] V g -V o =0 (9)

[0092] That is, the virtual electromotive force compensation relationship is constructed as:

[0093]

[0094] In the formula, h Ucom is the virtual electromotive force compensation coefficient.

[0095] Combining the above control with adaptive control theory, the converter can quickly reach the synchronization state when adapting to different working conditions during pre-synchronization with the power grid. The exponential function is used to construct the compensation coefficient and the following adaptive rules are designed:

[0096]

[0097] In the formula, k iT and K iU are the initial values ​​of virtual torque compensation coefficient and virtual electromotive force compensation coefficient, respectively, rT and k rU They are the virtual torque compensation adjustment coefficient and the virtual electromotive force compensation adjustment coefficient respectively.

[0098] Step S4: In off-grid mode, the converter output voltage and grid voltage are input into the adaptive virtual torque compensation controller, and the adaptive virtual torque and adaptive virtual electromotive force compensation are output and compensated to the virtual synchronous generator control equation of the converter, that is, the pre-synchronization process is started to achieve the purpose of smooth grid connection.

[0099] Furthermore, in step S4, the three-phase voltage output by the converter and the three-phase voltage of the grid are collected as control quantities through the voltage sensor and input into the adaptive virtual torque compensation controller. The virtual torque compensation coefficient and the virtual electromotive force compensation coefficient are calculated by combining formula (11) and formula (12). The adaptive virtual torque and adaptive virtual electromotive force compensation quantities are calculated by formula (7) and formula (10). The reference electromotive force and reference angular frequency are obtained through the improved control equation of the virtual synchronous generator, i.e., formula (2). The voltage and current dual closed-loop control is then used to enable the converter to adjust the output voltage amplitude, angular frequency and phase, thereby achieving synchronization with the grid voltage.

[0100] In a specific embodiment, a simulation platform is used to build Figure 1 The virtual synchronous generator control system of the three-phase three-level T-type topology is shown. The converter is initially in off-grid operation mode, with a 10KW local load, a rated active power of 30KW, and a circuit breaker in the disconnected state. At 1.5s, the pre-synchronization switch is started, and at 1.7s, the pre-synchronization is completed, the circuit breaker is closed, and the converter operates in the grid-connected operation mode. Figure 2 is the fixed virtual torque compensation coefficient h Tcom 6, 8, 10 and the change of the frequency pre-synchronization comparison process under the adaptive virtual torque compensation coefficient proposed by the present invention. Figure 2 It can be seen that when the virtual torque compensation coefficient is small, the frequency drop is large when the pre-synchronization is turned on, the frequency recovery is slow, and there is a long pre-synchronization overshoot. When the virtual torque compensation coefficient is large, the frequency drop is small when the pre-synchronization is turned on, and the frequency recovery is fast, but the frequency pre-synchronization process has a large overshoot, and the pre-synchronization process consumes a short time; when the adaptive virtual torque compensation coefficient is used, there is less frequency drop, less frequency shock, faster frequency recovery, and faster pre-synchronization time during the pre-synchronization process. The above examples can prove that the pre-synchronization control strategy of the virtual synchronous generator with adaptive virtual torque compensation adopted by the present invention can effectively improve the shortcomings of large frequency drop, long frequency recovery time, large frequency shock, and long pre-synchronization process consumption time during the pre-synchronization process.

[0101] Figure 3 When the pre-synchronization method proposed in the present invention is used, the voltage at both ends of the circuit breaker has an obvious phase difference before the pre-synchronization starts. The pre-synchronization is started at 1.5s. At about 1.7s, the output voltage of the converter and the grid voltage images are basically coincident. The output voltage amplitude, angular frequency and phase of the converter basically reach the grid-connected standard. The circuit breaker is closed to perform the grid-connected operation. Figure 4 The voltage and current waveforms of the converter output are as follows: From the pre-synchronization process to the closing of the circuit breaker, there is no obvious distortion of the voltage and current, and the voltage and current smoothly transition to the grid connection. Figure 5The output current waveform of the pre-synchronization process converter is compared under the fixed virtual torque compensation coefficient and the adaptive virtual torque compensation coefficient. It can be seen that the output current of the converter off-grid switching and grid-connected switching is smoother under the adaptive virtual torque compensation coefficient. Figure 6 The active power and reactive power waveforms output by the converter show that the active power and reactive power fluctuate slightly when connected to the grid, and then return to the rated value without obvious overshoot and distortion. Figure 7 The output active power waveform of the pre-synchronization process converter under fixed virtual torque compensation coefficient and adaptive virtual torque compensation coefficient is compared. Under the adaptive virtual torque compensation coefficient, the output active power fluctuation of the converter is smaller when it is switched off-grid and connected to the grid. Figure 8 The reactive power waveform of the converter output during the pre-synchronization process is compared under the fixed virtual torque compensation coefficient and the adaptive virtual torque compensation coefficient. When the adaptive virtual torque compensation coefficient is used, the output reactive power of the converter does not have much overshoot and has smaller fluctuation when switching off-grid and connecting to the grid.

[0102] It should be noted that, for the sake of convenience, the aforementioned method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited to the described order of actions, because according to the present invention, certain steps can be performed in other orders or simultaneously.

[0103] Based on the same idea as the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation in the above-mentioned embodiment, the present invention also provides a virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation, which can be used to execute the above-mentioned virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation. For ease of explanation, in the structural schematic diagram of the embodiment of the virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation, only the parts related to the embodiment of the present invention are shown. Those skilled in the art can understand that the illustrated structure does not constitute a limitation on the device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0104] See also Fig. 9 In another embodiment of the present application, a virtual synchronous generator pre-synchronization control system 100 based on adaptive virtual torque compensation is provided, the system comprising a first control equation building module 101, a second control equation building module 102, a compensation amount calculation module 103 and a grid voltage synchronization module 104;

[0105] The first control equation building module 101 is used to establish the control equation of the virtual generator of the energy storage converter according to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method;

[0106] The second control equation construction module 102 is used to construct an adaptive virtual torque compensation controller, and add adaptive virtual torque and adaptive virtual electromotive force compensation to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation;

[0107] The compensation amount calculation module 103 is used to use the output voltage of the energy storage converter and the grid voltage as control quantities, and calculate the compensation amounts of the adaptive virtual torque and the adaptive virtual electromotive force through the adaptive virtual torque compensation controller;

[0108] The grid voltage synchronization module 104 is used to input the output voltage of the energy storage converter and the grid voltage into the adaptive virtual torque compensation controller in the off-grid mode, output the compensation amount of the adaptive virtual torque and the adaptive virtual electromotive force, and compensate them to the virtual synchronous generator control equation of the energy storage converter, thereby realizing the synchronization of the grid voltage.

[0109] It should be noted that the virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation of the present invention corresponds one to one with the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation of the present invention. The technical features and beneficial effects described in the embodiment of the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation are applicable to the embodiment of the virtual synchronous generator pre-synchronization control based on adaptive virtual torque compensation. For specific contents, please refer to the description in the embodiment of the method of the present invention. It will not be repeated here. This is hereby declared.

[0110] In addition, in the implementation manner of the virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation in the above-mentioned embodiment, the logical division of each program module is only an example. In actual application, the above-mentioned functions can be assigned to different program modules as needed, for example, for the convenience of corresponding hardware configuration requirements or software implementation. That is, the internal structure of the virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation is divided into different program modules to complete all or part of the functions described above.

[0111] See also Fig.10 In one embodiment, an electronic device for implementing a virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation is provided. The electronic device 200 may include a first processor 201, a first memory 202 and a bus, and may also include a computer program stored in the first memory 202 and executable on the first processor 201, such as a virtual synchronous generator pre-synchronization control program 203 based on adaptive virtual torque compensation.

[0112] The first memory 202 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the first memory 202 can be an internal storage unit of the electronic device 200, such as a mobile hard disk of the electronic device 200. In other embodiments, the first memory 202 can also be an external storage device of the electronic device 200, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 200. Further, the first memory 202 can also include both an internal storage unit of the electronic device 200 and an external storage device. The first memory 202 can not only be used to store application software and various types of data installed in the electronic device 200, such as the code of the virtual synchronous generator pre-synchronization control program 203 based on adaptive virtual torque compensation, but also can be used to temporarily store data that has been output or is to be output.

[0113] In some embodiments, the first processor 201 may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips, etc. The first processor 201 is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes various functions and processes data of the electronic device 200 by running or executing programs or modules stored in the first memory 202, and calling data stored in the first memory 202.

[0114] Fig.10 Only an electronic device with components is shown, and those skilled in the art will understand that Fig.10 The structure shown does not constitute a limitation on the electronic device 200 , and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0115] The virtual synchronous generator pre-synchronization control program 203 based on adaptive virtual torque compensation stored in the first memory 202 of the electronic device 200 is a combination of multiple instructions. When running in the first processor 201, it can achieve:

[0116] According to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method, the control equation of the virtual generator of the energy storage converter is established;

[0117] An adaptive virtual torque compensation controller is constructed, and adaptive virtual torque and adaptive virtual electromotive force compensation are added to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation.

[0118] The output voltage of the energy storage converter and the grid voltage are used as control quantities, and the compensation quantities of the adaptive virtual torque and the adaptive virtual electromotive force are calculated through the adaptive virtual torque compensation controller;

[0119] In off-grid mode, the output voltage of the energy storage converter and the grid voltage are input into the adaptive virtual torque compensation controller, and the compensation of the adaptive virtual torque and the adaptive virtual electromotive force is output and compensated to the virtual synchronous generator control equation of the energy storage converter, thereby achieving synchronization of the grid voltage.

[0120] Furthermore, if the module / unit integrated in the electronic device 200 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0121] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0122] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation, characterized in that: The steps include: According to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method, the control equation of the virtual generator of the energy storage converter is established; An adaptive virtual torque compensation controller is constructed, and adaptive virtual torque and adaptive virtual electromotive force compensation are added to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation. The output voltage of the energy storage converter and the grid voltage are used as control quantities, and the compensation quantities of the adaptive virtual torque and the adaptive virtual electromotive force are calculated through the adaptive virtual torque compensation controller; In off-grid mode, the output voltage of the energy storage converter and the grid voltage are input into the adaptive virtual torque compensation controller, and the compensation of the adaptive virtual torque and the adaptive virtual electromotive force is output and compensated to the virtual synchronous generator control equation of the energy storage converter, thereby achieving synchronization of the grid voltage.

2. The method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation according to claim 1, characterized in that: The control equation of the virtual generator is specifically: Where P ref is the reference active power, Q ref is the reference reactive power, w0 is the reference angular frequency, U n is the effective value of the reference voltage, U n is the reference voltage amplitude, P e is the converter output active power, Q e is the reactive power output by the converter, U is the effective value of the converter output voltage, w is the angular frequency of the converter output voltage, θ is the phase of the converter output voltage, E is the converter terminal voltage, E0 is the rated no-load electromotive force, J is the moment of inertia, D is the damping coefficient, k p is the active power droop coefficient, k q is the reactive power droop coefficient, k i is the integration coefficient.

3. The virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation according to claim 1 is characterized in that: The improved control equation of the virtual synchronous generator based on adaptive virtual torque compensation is specifically: Where, T com is the adaptive virtual torque compensation, U com is the adaptive virtual electromotive force compensation, S i Indicates the inverter on-grid and off-grid operation state, S i 0 means off-grid, S i 1 indicates grid connection.

4. The method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation according to claim 1, characterized in that: An adaptive virtual torque compensation controller is designed to obtain the adaptive virtual torque compensation and the adaptive virtual electromotive force compensation. In the stationary two-axis coordinate system, the converter output voltage and the grid voltage are: Where V oα and V oβ are the α-axis voltage component and β-axis voltage component output by the converter under the stationary two-phase coordinate axis, V gα and V gβ are the α-axis voltage component and β-axis voltage component of the grid voltage output under the static two-phase coordinate axis, V o and V g are the converter output voltage amplitude and grid voltage amplitude, w0 and w g are the converter output voltage angular frequency and the grid voltage angular frequency, θ o and θ g They are the converter output voltage phase and grid voltage phase respectively.

5. The method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation according to claim 4 is characterized in that: In order to construct the angular frequency and phase relationship between the converter output voltage and the grid voltage, the converter output voltage and the grid voltage in the above-mentioned stationary two-axis coordinate system are cross-multiplied to obtain the first relationship: V gα V pβ -V gβ V oα =V o V g sin[(w g -w0)t+(θ g -θ o )] When the converter output voltage and grid voltage angular frequency and phase are synchronized, the first relation is obtained: V gα V oβ -V gβ V oα =0 That is, the virtual torque compensation relationship is constructed as: T com =h Tcom (V gα V oβ -V gβ V oα ) In the formula, h Tcom is the virtual torque compensation coefficient; According to the difference between the converter output voltage and the grid voltage amplitude, the second relationship is obtained: When the converter output voltage and grid voltage amplitude are synchronized, the above second relation is obtained: V g -V o =0 That is, the virtual electromotive force compensation relationship is constructed as: In the formula, h Ucom is the virtual electromotive force compensation coefficient.

6. The method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation according to claim 5, characterized in that: The adaptive rule of the adaptive virtual torque compensation controller is as follows: In the formula, k iT and K iU are the initial values ​​of virtual torque compensation coefficient and virtual electromotive force compensation coefficient, respectively, rT and k rU They are the virtual torque compensation adjustment coefficient and the virtual electromotive force compensation adjustment coefficient respectively.

7. The method for pre-synchronization control of a virtual synchronous generator based on adaptive virtual torque compensation according to claim 6, characterized in that: To achieve the synchronization of grid voltage, specifically: The voltage sensor collects the three-phase voltage output by the converter and the three-phase voltage of the power grid as the control quantity, which is input into the adaptive virtual torque compensation controller. The virtual torque compensation coefficient and the virtual electromotive force compensation coefficient are calculated in combination with the adaptive rule of the adaptive virtual torque compensation controller. The compensation amounts of the adaptive virtual torque and the adaptive virtual electromotive force are calculated using the virtual torque compensation relationship and the virtual electromotive force compensation relationship. The reference electromotive force and the reference angular frequency are obtained through the control equation of the improved virtual synchronous generator, and then handed over to the voltage and current dual closed-loop control, so that the converter adjusts the output voltage amplitude, angular frequency and phase, so as to achieve synchronization with the power grid voltage.

8. A virtual synchronous generator pre-synchronization control system based on adaptive virtual torque compensation, characterized in that: It includes a first control equation building module, a second control equation building module, a compensation amount calculation module and a power grid voltage synchronization module; The first control equation building module is used to establish the control equation of the virtual generator of the energy storage converter according to the rotor motion equation and excitation control equation of the synchronous generator and the droop control method; The second control equation construction module is used to construct an adaptive virtual torque compensation controller, and add adaptive virtual torque and adaptive virtual electromotive force compensation to the virtual synchronous generator control equation to obtain an improved virtual synchronous generator control equation based on adaptive virtual torque compensation; The compensation amount calculation module is used to use the output voltage of the energy storage converter and the grid voltage as control quantities, and calculate the compensation amounts of the adaptive virtual torque and the adaptive virtual electromotive force through the adaptive virtual torque compensation controller; The grid voltage synchronization module is used to input the output voltage of the energy storage converter and the grid voltage into the adaptive virtual torque compensation controller in the off-grid mode, output the compensation amount of the adaptive virtual torque and the adaptive virtual electromotive force, and compensate them to the virtual synchronous generator control equation of the energy storage converter, thereby realizing the synchronization of the grid voltage.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor so that the at least one processor can execute the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation as described in any one of claims 1-7.

10. A computer-readable storage medium storing a program, characterized in that: When the program is executed by the processor, the virtual synchronous generator pre-synchronization control method based on adaptive virtual torque compensation as described in any one of claims 1 to 7 is implemented.

Images