Method and device for frequency recovery and active oscillation suppression of multi-parallel energy storage power supply system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN UNIV
- Filing Date
- 2026-07-07
- Publication Date
- 2026-08-07
AI Technical Summary
因此，现有控制方法在极端灾害下的弱通信或无通信孤岛运行场景中，仍难以同时实现多并联储能供电系统的有功功率振荡抑制和稳态功率分配关系保持
[0034]The beneficial effects of the technical solutions provided in some embodiments of this application include at least the following: achieving error-free recovery of the common AC bus frequency and effective suppression of active power interaction oscillation without relying on communication between energy storage converters, while maintaining the original steady-state active power distribution relationship of each energy storage converter.
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Figure CN122532998A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microgrid control and parallel operation control technology of power electronic converters, and in particular to a method and apparatus for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system. Background Technology
[0002] Extreme disasters may force some distribution areas or microgrids into islanded operation. To ensure continuous power supply to critical loads during disasters, multiple energy storage converters can be connected in parallel to form an islanded power supply system, providing voltage and frequency support for local loads. In such multi-parallel energy storage power supply systems, energy storage converters typically employ strategies such as virtual synchronous machine control to simulate the inertia and damping characteristics of synchronous generators, thereby improving the system's frequency support capability and dynamic stability. However, traditional multi-energy storage converter parallel control methods usually rely on the active power-frequency droop control relationship to achieve load power sharing, but its droop characteristic can lead to system frequency deviation. Due to the mismatch between converter control parameters and line parameters, differences in the dynamic responses of each energy storage unit will occur, resulting in active power oscillations. Frequency deviation and active power oscillations not only reduce the power quality of the islanded power supply system but may also affect the normal operation of sensitive loads and important equipment. Therefore, how to achieve frequency recovery and oscillation suppression in multi-parallel energy storage power supply systems under islanded operation conditions is a crucial issue for ensuring stable system operation and reliable power supply to critical loads.
[0003] To address the aforementioned steady-state frequency deviation problem, existing technologies typically employ secondary frequency control methods to compensate for the frequency commands of energy storage converters. These methods mainly include centralized control based on a central controller and distributed control based on information exchange between adjacent units. Centralized methods usually rely on a central controller to collect operating information such as frequency and power from each energy storage converter and generate unified frequency compensation commands; distributed methods achieve coordinated frequency recovery through information exchange between adjacent energy storage converters. While these methods can achieve error-free frequency regulation to a certain extent, their control effectiveness depends on the reliability and real-time performance of the communication link. In extreme disaster scenarios, communication link delays, packet loss, and even interruptions are unavoidable. Secondary frequency control methods reliant on communication may experience compensation lag, decreased control performance, or even control failure, which is detrimental to the reliable operation of multi-parallel energy storage power supply systems under weak or no communication conditions. Therefore, existing frequency recovery methods still suffer from strong reliance on communication and insufficient operational reliability in disaster scenarios.
[0004] Furthermore, when multiple energy storage converters operate in parallel, active power oscillations are easily triggered due to factors such as differences in the impedance of each branch line, mismatch in the control parameters of the energy storage converters, and load disturbances. During islanded power supply processes following extreme disasters, the switching of critical loads, rapid adjustment of energy storage power, and changes in the local power supply range become more frequent, exacerbating the active power oscillation problem. Current technologies typically employ methods such as increasing virtual damping or adjusting virtual inertia to suppress these oscillations. While simply increasing virtual damping can improve the system's damping capability to some extent, it may alter the original steady-state active power distribution relationship, making it difficult for multiple energy storage converters to bear the load power according to the preset proportions. Adjusting virtual inertia, on the other hand, may affect the system's dynamic response speed and stability margin. Using communication coordination to suppress active power oscillations also increases dependence on communication links, facing reliability issues similar to those encountered with frequency recovery methods. Therefore, existing control methods still struggle to simultaneously suppress active power oscillations and maintain steady-state power distribution relationships in islanded operation scenarios with weak or no communication under extreme disasters. Summary of the Invention
[0005] Based on the above problems, this application provides a method and apparatus for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system, which can simultaneously eliminate frequency deviation and suppress active power oscillation under conditions without communication.
[0006] In a first aspect, embodiments of this application provide a method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system, applied to various energy storage converters in isolated distribution areas after a disaster in islanded microgrids or distribution networks. The proposed scenario includes at least two energy storage converters, each connected to a common AC bus via line impedance. The method includes:
[0007] Collect local operating information and common AC bus voltage; local operating information includes the output active power of each energy storage converter;
[0008] A common physical variable is constructed based on the common AC bus voltage. The common physical variable is used to characterize the deviation of the common AC bus frequency from the rated frequency.
[0009] The frequency recovery control quantity is generated based on common physical variables. The frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency.
[0010] The oscillation component in the output active power of the energy storage converter is extracted, and an oscillation suppression control quantity is generated based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters.
[0011] The frequency recovery control and oscillation suppression control are introduced into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter.
[0012] The three-phase voltage reference signal is synthesized based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, and the corresponding energy storage converter is controlled to output electrical energy.
[0013] In one possible embodiment, the common physical variable is obtained by performing an inner product operation between the common AC bus voltage and the standard three-phase sinusoidal reference vector.
[0014] In one possible embodiment, under small work angle conditions, the common physical variables satisfy the following equivalence relationship:
[0015]
[0016] Among them, e ωi U is the common physical variable corresponding to the i-th energy storage converter. bus The amplitude of the common AC bus voltage, ω n The rated angular frequency, ω bus ω is the angular frequency of the common AC bus, and s is the Laplace operator.
[0017] In one possible embodiment, the frequency recovery control quantity is generated as follows:
[0018]
[0019] Where, ω FRi Let a be the frequency recovery control value for the i-th energy storage converter. i e is the steady-state frequency recovery coefficient. ωi Let be the common physical variable corresponding to the i-th energy storage converter; the frequency recovery control quantity has zero-error regulation characteristics relative to the frequency deviation of the common AC bus.
[0020] In one possible embodiment, the oscillation suppression control quantity is generated according to the following relationship:
[0021]
[0022] Among them, P TDCi Let b be the oscillation suppression control quantity for the i-th energy storage converter. i τ is the oscillation suppression coefficient. i P is the filtering time constant. ei Let be the output active power of the i-th energy storage converter, and s be the Laplace operator. The oscillation suppression control quantity extracts the oscillation component in the output active power through high-pass filtering and feeds the oscillation component back to the active-frequency control loop of the energy storage converter.
[0023] In one possible embodiment, the frequency recovery control parameters of each energy storage converter are set in the same way so that the steady-state active power distribution relationship of the multi-parallel energy storage power supply system remains unchanged after the frequency recovery control is introduced.
[0024] In one possible embodiment, both the frequency recovery control quantity and the oscillation suppression control quantity are generated in the local controller of the energy storage converter, and each energy storage converter collects its own local operating information and the common AC bus voltage.
[0025] Secondly, embodiments of this application provide a frequency recovery and active power oscillation suppression device for a multi-parallel energy storage power supply system. This device includes: a data acquisition module, a construction module, a generation module, an extraction module, and a control module, wherein:
[0026] The data acquisition module is used to collect local operating information and the common AC bus voltage; the local operating information includes the output active power of each energy storage converter;
[0027] The construction module is used to construct common physical variables based on the common AC bus voltage. The common physical variables are used to characterize the deviation of the common AC bus frequency from the rated frequency.
[0028] The generation module is used to generate frequency recovery control quantities based on common physical variables. The frequency recovery control quantities are used to compensate for the steady-state deviation of the common AC bus frequency.
[0029] The extraction module is used to extract the oscillation component in the output active power of the energy storage converter itself, and generate an oscillation suppression control quantity based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters.
[0030] The correction module is used to introduce frequency recovery control and oscillation suppression control into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter.
[0031] The control module is used to synthesize a three-phase voltage reference signal based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, and to control the corresponding energy storage converter to output electrical energy.
[0032] Thirdly, embodiments of this application provide a computer storage medium storing multiple instructions adapted for loading by a processor and executing the steps of the above-described method.
[0033] Fourthly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being adapted to be loaded by the processor and to execute the steps of the above-described method.
[0034] The beneficial effects of the technical solutions provided in some embodiments of this application include at least the following: achieving error-free recovery of the common AC bus frequency and effective suppression of active power interaction oscillation without relying on communication between energy storage converters, while maintaining the original steady-state active power distribution relationship of each energy storage converter. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 This is a schematic diagram of the structure of a multi-parallel energy storage power supply system provided in an embodiment of this application;
[0037] Figure 2 A flowchart illustrating the frequency recovery and active power oscillation suppression method for a multi-parallel energy storage power supply system provided in this application embodiment;
[0038] Figure 3 This is a schematic diagram of the control topology of a single energy storage converter provided in an embodiment of this application;
[0039] Figure 4 A structural block diagram of a frequency recovery and active power oscillation suppression device for a multi-parallel energy storage power supply system provided in an embodiment of this application;
[0040] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0041] To make the features and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0042] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0043] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.
[0044] As mentioned earlier, existing multi-parallel energy storage power supply systems suffer from steady-state frequency deviation due to active power-frequency droop control when operating in islanded environments. Conventional secondary frequency control methods are highly dependent on communication links and lack reliability in communication-constrained scenarios. At the same time, line impedance differences and control parameter mismatches can easily cause active power interactive oscillations, and existing damping adjustment methods may alter the steady-state power distribution relationship.
[0045] In view of this, this application provides a method and apparatus for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system. The aim is to achieve error-free recovery of the common AC bus frequency and effective suppression of active power oscillation without relying on communication between energy storage converters, while maintaining the original steady-state active power distribution relationship of each energy storage converter.
[0046] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a multi-parallel energy storage power supply system provided in an embodiment of this application.
[0047] like Figure 1 As shown, this multi-parallel energy storage power supply system includes at least two energy storage converters (energy storage 1...energy storage i...energy storage n), a common AC bus, line impedance, and loads. Each energy storage converter is connected to the common AC bus via its corresponding line impedance. The common AC bus is connected to the local load, forming an islanded microgrid power supply architecture. In this embodiment, the local controllers of each energy storage converter do not need to communicate with each other. Instead, the common AC bus voltage is used as a common physical quantity that can be directly acquired by each energy storage converter. Frequency recovery control information is constructed based on this common physical quantity, and oscillation suppression control quantity is generated by combining the oscillation component of its own output active power. This achieves frequency recovery and active power oscillation suppression under communication-free conditions.
[0048] Please see Figure 2 , Figure 2 This is a flowchart illustrating the frequency recovery and active power oscillation suppression method for a multi-parallel energy storage power supply system provided in an embodiment of this application. Figure 2As shown, the methods for frequency recovery and active power oscillation suppression in multi-parallel energy storage power supply systems may include at least:
[0049] S201. Collect local operating information and common AC bus voltage.
[0050] Specifically, each energy storage converter acquires one or more of the following through a local sampling stage: its own output voltage, output current, output active power, output reactive power, and internal controller operating status information. Simultaneously, it acquires the three-phase voltage signal at the common AC bus. The output active and reactive power can be calculated from the output voltage and current of the energy storage converters, while the common AC bus voltage is obtained from the voltage sampling unit at the common coupling point. The common AC bus voltage is acquired because it is consistent across all energy storage converters in the parallel system and can serve as a common physical quantity for constructing subsequent frequency recovery information. The output active power is acquired to extract its oscillating components to suppress active power interaction oscillations.
[0051] In one possible implementation, each energy storage converter relies solely on locally measurable information to calculate subsequent control parameters, without needing to receive frequency, power, phase angle, or control parameter information from other energy storage converters. All control parameters are generated locally, thus avoiding the impact of communication delays or interruptions on control performance. This step lays the data foundation for subsequent communication-free coordinated control through localized data acquisition.
[0052] S202. Construct common physical variables based on the common AC bus voltage. The common physical variables are used to characterize the deviation of the common AC bus frequency from the rated frequency.
[0053] Specifically, each energy storage converter uses the common AC bus voltage as a common physical quantity that can be directly acquired by all of them. They then use this common AC bus voltage and a locally generated standard reference signal to construct a common physical variable characterizing the operating state of the common AC bus. Because the common AC bus voltage is consistent across all energy storage converters in the parallel system, each converter can obtain information related to the system frequency deviation based on this common physical variable without needing to communicate.
[0054] Specifically, the common physical variables are obtained by performing an inner product operation between the common AC bus voltage and the standard three-phase sinusoidal reference vector, and the expression is as follows:
[0055] (1)
[0056] Among them, e ωi Let u be the common physical variable corresponding to the i-th energy storage converter. busThe common AC bus voltage is given, sinθ0 is the standard three-phase sinusoidal reference vector, and θ0 is the standard reference phase angle. When the amplitude of the common AC bus voltage is u... bus The phase angle of the common AC bus is δ bus In this case, the common physical variable can be expressed as:
[0057] (2)
[0058] In one possible implementation, under normal operating conditions, the deviation between the common AC bus phase angle and the standard reference phase angle is small, and a small-angle approximation can be used to obtain:
[0059] (3)
[0060] Where, ω bus Here, 's' represents the common AC bus angular frequency, and 's' represents the Laplace operator. Therefore, the common physical variable reflects the deviation of the common AC bus frequency from the rated frequency. Thus, each energy storage converter can construct the control quantity required for frequency recovery using the common AC bus voltage without directly measuring the system frequency or obtaining global frequency information through communication. This embodiment preferably employs a direct construction method using inner product operations, as it does not rely on the small power angle assumption and has a wider range of applications. Through this step, each energy storage converter obtains unified information related to the system frequency deviation without directly measuring the frequency or obtaining global frequency information through communication.
[0061] S203. Generate frequency recovery control quantity based on common physical variables. The frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency.
[0062] Specifically, each energy storage converter's local controller generates a frequency recovery control quantity based on common physical variables. This frequency recovery control quantity acts on the active-frequency control loop of the energy storage converter to compensate for the deviation of the common AC bus frequency from the rated frequency. When load disturbances cause the common AC bus frequency to deviate from its rated value, the frequency recovery control quantity can adjust the generation process of the energy storage converter's output angular frequency and voltage reference phase angle, gradually restoring the system frequency to near the rated frequency, thereby reducing or eliminating the steady-state frequency deviation caused by traditional active-frequency control.
[0063] Specifically, the frequency recovery control quantity is generated according to the following relationship:
[0064] (4)
[0065] Where, ω FRi Let a be the frequency recovery control value for the i-th energy storage converter. i e is the steady-state frequency recovery coefficient.ωi Let be the common physical variable corresponding to the i-th energy storage converter. Substituting formula (3) into formula (4), we get:
[0066] (5)
[0067] As shown in the above equation, the frequency recovery control quantity has zero-error adjustment characteristics relative to the frequency deviation of the common AC bus. This integral element enables the control quantity to adjust the constant frequency deviation without error; that is, as long as the bus frequency deviates from the rated value, the control quantity will continue to integrate until the deviation is zero. When load disturbances cause the bus frequency to drop, this control quantity positively compensates the active-frequency control element of the energy storage converter, gradually raising the frequency to the rated value; conversely, it provides negative compensation. This step fundamentally eliminates the inherent steady-state frequency deviation of traditional droop control through integral action.
[0068] S204. Extract the oscillation component from the output active power of the energy storage converter itself, and generate an oscillation suppression control quantity based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters.
[0069] Specifically, each energy storage converter's local controller extracts the oscillation component from its own output active power and generates an oscillation suppression control quantity based on this component. This oscillation suppression control quantity reflects the dynamic oscillation characteristics of the output active power under conditions of load disturbance, line impedance differences, or control parameter mismatch, and feeds this oscillation characteristic back to the active-frequency control loop of the energy storage converter. In this way, without changing the steady-state active power distribution relationship, the equivalent damping capability of the multi-parallel energy storage power supply system can be improved, and active power interaction oscillations in the parallel system can be suppressed.
[0070] Specifically, the oscillation suppression control quantity is generated according to the following relationship:
[0071] (6)
[0072] Among them, P TDCi Let b be the oscillation suppression control quantity for the i-th energy storage converter. i τ is the oscillation suppression coefficient. i P is the filtering time constant. ei Let τ be the output active power of the i-th energy storage converter, and s be the Laplace operator. The oscillation suppression control quantity extracts the oscillation component from the output active power through a high-pass filter and feeds this oscillation component back to the active-frequency control loop of the energy storage converter. The cutoff frequency of this high-pass filter is determined by τ. iThe control variable can be set for typical oscillation frequency bands. When active power oscillations are caused by load disturbances or parameter mismatches, this control variable is dynamically fed back to the active power-frequency control loop, effectively increasing system damping. In steady state, since the high-pass filter does not respond to the DC component, the oscillation suppression control variable approaches zero and does not affect the steady-state distribution of active power. This embodiment preferably uses a first-order high-pass filter, which has a simple structure and easy parameters to tune.
[0073] S205. Introduce the frequency recovery control quantity and oscillation suppression control quantity into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter.
[0074] Specifically, frequency recovery control and oscillation suppression control are superimposed on the original active-frequency control loop of the energy storage converter. The frequency recovery control is used to compensate for system frequency deviation, and the oscillation suppression control is used to suppress oscillating components in the output active power. With their combined effect, the active-frequency control loop of the energy storage converter can simultaneously achieve steady-state frequency recovery and transient oscillation suppression during load changes, and further correct the generation process of the voltage reference phase angle, enabling all energy storage converters to maintain coordinated operation even without communication. The active-frequency control loop of the i-th energy storage converter satisfies the following relationship:
[0075] (7)
[0076] Among them, J i Let ω be the virtual inertia of the i-th energy storage converter. i Let P be the output angular frequency of the i-th energy storage converter. mi Let D be the active power setpoint for the i-th energy storage converter. i Let be the damping coefficient of the i-th energy storage converter. In the above control relationship, the frequency recovery control variable is used to compensate for the frequency deviation of the common AC bus, enabling the system to achieve frequency recovery after load disturbance; the oscillation suppression control variable is used to suppress the oscillating component in the output active power, reducing the active power interaction oscillation during the parallel operation of multiple energy storage converters. Simultaneously, the voltage reference phase angle is obtained by integrating the output angular frequency, satisfying: sδ i =ω i , where δ i Let be the virtual phase angle of the i-th energy storage converter.
[0077] Please see Figure 3 , Figure 3 This is a schematic diagram of the control topology of a single energy storage converter provided in an embodiment of this application, as shown below. Figure 3As shown, for a single energy storage converter, its local control structure includes a common physical variable construction stage, a frequency recovery control stage, an oscillation suppression control stage, an active power-frequency control stage, a reactive power-voltage control stage, and a voltage reference generation stage. The common AC bus voltage is input to the common physical variable construction stage, and after processing, the common physical variable is obtained. The common physical variable is input to the frequency recovery control stage, generating a frequency recovery control quantity. The active power output from the energy storage converter is input to the oscillation suppression control stage, generating an oscillation suppression control quantity. The frequency recovery control quantity and the oscillation suppression control quantity work together on the active power-frequency control stage to correct the output angular frequency and voltage reference phase angle. The reactive power-voltage control stage generates a voltage amplitude reference. The voltage amplitude reference and the voltage reference phase angle together generate a three-phase voltage reference signal, which is finally output through the inverter control stage.
[0078] In one possible implementation, the frequency recovery control parameters of each energy storage converter are set in the same way, i.e., m1=m2=……=m i Through the above settings, the steady-state active power distribution relationship of the multi-parallel energy storage power supply system can remain unchanged after the introduction of the frequency recovery control. When the system enters steady state, the high-pass filter corresponding to the oscillation suppression control does not respond to the DC component; therefore, the steady-state output of the oscillation suppression control is zero. Simultaneously, under the action of the frequency recovery control, the common AC bus angular frequency and the output angular frequency of each energy storage converter are restored to their rated angular frequencies, i.e.: ω i =ω bus =ω n At this point, the multi-parallel energy storage power supply system achieves frequency restoration.
[0079] Furthermore, when the steady-state active power is distributed among the energy storage converters according to the damping coefficient, the steady-state active power variation of each energy storage converter satisfies the following proportional relationship:
[0080] (8)
[0081] Where, ΔP e1 ΔP e2 ΔP ei These represent the steady-state active power changes of the corresponding energy storage converters, D1, D2, and D... i These are the damping coefficients of the corresponding energy storage converters.
[0082] S206. Based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, a three-phase voltage reference signal is synthesized to control the corresponding energy storage converter to output electrical energy.
[0083] Specifically, the energy storage converter synthesizes a three-phase voltage reference signal based on the voltage reference phase angle corrected by the active-frequency control loop and the internal electromotive force amplitude generated by the reactive-voltage control loop. The reactive-voltage control loop generates a voltage amplitude reference based on the deviation between the reactive power output of the energy storage converter and the given reactive power value, and then combines this with the voltage reference phase angle to generate the three-phase voltage reference signal. This three-phase voltage reference signal, after passing through a voltage-current inner loop or pulse width modulation loop, is applied to the power conversion unit of the energy storage converter, causing each energy storage converter to output electrical energy according to the corresponding voltage amplitude, frequency, and phase angle, thereby realizing the parallel operation control of multiple energy storage converters in a multi-parallel energy storage power supply system. Each energy storage converter independently executes the above steps, achieving parallel operation at a common AC bus. This step ultimately converts the preceding control quantities into the actual output voltage, completing the closed-loop control for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system under conditions without communication.
[0084] This application provides a method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system. It constructs a frequency recovery control quantity through the common AC bus voltage to eliminate steady-state frequency deviation, and extracts the active power oscillation component to generate a suppression control quantity to improve transient damping. Both are generated in the local controller and do not require communication. Under load disturbance and parameter mismatch conditions, it can still effectively suppress active power interactive oscillation and restore the rated frequency, while maintaining the original steady-state active power distribution relationship. It is simple to implement, has good dynamic performance, and is easy to expand.
[0085] Please see Figure 4 , Figure 4 This is a structural block diagram of the frequency recovery and active power oscillation suppression device for a multi-parallel energy storage power supply system provided in an embodiment of this application. Figure 4 As shown: The frequency recovery and active power oscillation suppression device 400 for a multi-parallel energy storage power supply system includes: a data acquisition module 410, a data construction module 420, a data generation module 430, a data extraction module 440, and a control module 460, wherein:
[0086] The acquisition module 410 is used to acquire local operating information and common AC bus voltage; the local operating information includes the output active power of each energy storage converter;
[0087] Construction module 420 is used to construct common physical variables based on the common AC bus voltage. The common physical variables are used to characterize the deviation of the common AC bus frequency from the rated frequency.
[0088] The generation module 430 is used to generate a frequency recovery control quantity based on common physical variables. The frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency.
[0089] The extraction module 440 is used to extract the oscillation component in the output active power of the energy storage converter itself, and generate an oscillation suppression control quantity based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters.
[0090] The correction module 450 is used to introduce frequency recovery control and oscillation suppression control into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter.
[0091] The control module 460 is used to synthesize a three-phase voltage reference signal based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, and to control the corresponding energy storage converter to output electrical energy.
[0092] It should be noted that the frequency recovery and active power oscillation suppression device for multi-parallel energy storage power supply systems provided in the above embodiments is only illustrated by the division of the above functional modules when performing the frequency recovery and active power oscillation suppression method for multi-parallel energy storage power supply systems. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the frequency recovery and active power oscillation suppression device for multi-parallel energy storage power supply systems and the embodiment of the frequency recovery and active power oscillation suppression method for multi-parallel energy storage power supply systems provided in the above embodiments belong to the same concept, and the implementation process is detailed in the method embodiment, which will not be repeated here.
[0093] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0094] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5 As shown, the electronic device 500 may include: at least one processor 501, at least one network interface 504, user interface 503, memory 505, and at least one communication bus 502.
[0095] The communication bus 502 is used to enable communication between these components.
[0096] The user interface 503 may include a display screen, and the optional user interface 503 may include a standard wired interface or a wireless interface.
[0097] The network interface 504 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).
[0098] The processor 501 may include one or more processing cores. The processor 501 connects to various parts within the electronic device 500 using various interfaces and lines, and performs various functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 505, and by calling data stored in the memory 505. Optionally, the processor 501 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 501 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 501 and may be implemented as a separate chip.
[0099] The memory 505 may include random access memory (RAM) or read-only memory. Optionally, the memory 505 may include a non-transitory computer-readable storage medium. The memory 505 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 505 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory 505 may also be at least one storage device located remotely from the aforementioned processor 501. Figure 5 As shown, the memory 505, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an application program for frequency recovery and active power oscillation suppression of multi-parallel energy storage power supply systems.
[0100] exist Figure 5In the illustrated electronic device 500, the user interface 503 is mainly used to provide an input interface for the user and to acquire user input data; while the processor 501 can be used to call the application program for frequency recovery and active power oscillation suppression of multi-parallel energy storage power supply system stored in the memory 505, and specifically perform the following operations:
[0101] Collect local operating information and common AC bus voltage; local operating information includes the output active power of each energy storage converter;
[0102] A common physical variable is constructed based on the common AC bus voltage. The common physical variable is used to characterize the deviation of the common AC bus frequency from the rated frequency.
[0103] The frequency recovery control quantity is generated based on common physical variables. The frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency.
[0104] The oscillation component in the output active power of the energy storage converter is extracted, and an oscillation suppression control quantity is generated based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters.
[0105] The frequency recovery control and oscillation suppression control are introduced into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter.
[0106] The three-phase voltage reference signal is synthesized based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, and the corresponding energy storage converter is controlled to output electrical energy.
[0107] In one possible embodiment, the common physical variable is obtained by performing an inner product operation between the common AC bus voltage and the standard three-phase sinusoidal reference vector.
[0108] In one possible embodiment, under small work angle conditions, the common physical variables satisfy the following equivalence relationship:
[0109]
[0110] Among them, e ωi U is the common physical variable corresponding to the i-th energy storage converter. bus The amplitude of the common AC bus voltage, ω n The rated angular frequency, ω bus ω is the angular frequency of the common AC bus, and s is the Laplace operator.
[0111] In one possible embodiment, the frequency recovery control quantity is generated as follows:
[0112]
[0113] Where, ω FRi Let a be the frequency recovery control value for the i-th energy storage converter. i e is the steady-state frequency recovery coefficient. ωi Let be the common physical variable corresponding to the i-th energy storage converter; the frequency recovery control quantity has zero-error regulation characteristics relative to the frequency deviation of the common AC bus.
[0114] In one possible embodiment, the oscillation suppression control quantity is generated according to the following relationship:
[0115]
[0116] Among them, P TDCi Let b be the oscillation suppression control quantity for the i-th energy storage converter. i τ is the oscillation suppression coefficient. i P is the filtering time constant. ei Let be the output active power of the i-th energy storage converter, and s be the Laplace operator. The oscillation suppression control quantity extracts the oscillation component in the output active power through high-pass filtering and feeds the oscillation component back to the active-frequency control loop of the energy storage converter.
[0117] In one possible embodiment, the frequency recovery control parameters of each energy storage converter are set in the same way so that the steady-state active power distribution relationship of the multi-parallel energy storage power supply system remains unchanged after the frequency recovery control is introduced.
[0118] In one possible embodiment, both the frequency recovery control quantity and the oscillation suppression control quantity are generated in the local controller of the energy storage converter, and each energy storage converter collects its own local operating information and the common AC bus voltage.
[0119] This application also provides a computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the above-described instructions. Figure 2 One or more steps in the illustrated embodiment. If the constituent modules of the above-described multi-parallel energy storage power supply system frequency recovery and active power oscillation suppression device are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.
[0120] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital versatile discs (DVDs)), or semiconductor media (e.g., solid state disks (SSDs)).
[0121] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The aforementioned storage medium includes various media capable of storing program code, such as read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation schemes can be combined arbitrarily.
[0122] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system, applied to energy storage converters in isolated microgrids or post-disaster isolated distribution areas in a distribution network, wherein the isolated microgrid or post-disaster isolated distribution area includes at least two energy storage converters, each energy storage converter being connected to a common AC bus via line impedance, characterized in that... The method includes: Collect local operating information and common AC bus voltage; the local operating information includes the output active power of each energy storage converter; A common physical variable is constructed based on the common AC bus voltage, and the common physical variable is used to characterize the deviation of the common AC bus frequency from the rated frequency; A frequency recovery control quantity is generated based on the common physical variables, and the frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency; The oscillation component in the output active power of the energy storage converter itself is extracted, and an oscillation suppression control quantity is generated based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage converters. The frequency recovery control quantity and the oscillation suppression control quantity are introduced into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter. Based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, a three-phase voltage reference signal is synthesized to control the corresponding energy storage converter to output electrical energy.
2. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 1, characterized in that, The common physical variables are obtained by performing an inner product operation between the common AC bus voltage and the standard three-phase sinusoidal reference vector.
3. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 2, characterized in that, Under small work angle conditions, the common physical variables satisfy the following equivalence relationship: Among them, e ωi U is the common physical variable corresponding to the i-th energy storage converter. bus The amplitude of the common AC bus voltage, ω n The rated angular frequency, ω bus ω is the angular frequency of the common AC bus, and s is the Laplace operator.
4. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 1, characterized in that, The frequency recovery control quantity is generated in the following manner: Where, ω FRi Let a be the frequency recovery control value for the i-th energy storage converter. i e is the steady-state frequency recovery coefficient. ωi For the i-th energy storage converter, there is a common physical variable; the frequency recovery control quantity has zero-error adjustment characteristics relative to the frequency deviation of the common AC bus.
5. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 1, characterized in that, The oscillation suppression control quantity is generated according to the following relationship: Among them, P TDCi Let b be the oscillation suppression control quantity for the i-th energy storage converter. i τ is the oscillation suppression coefficient. i P is the filtering time constant. ei Let be the output active power of the i-th energy storage converter, and s be the Laplace operator; the oscillation suppression control quantity extracts the oscillation component in the output active power through high-pass filtering and feeds the oscillation component back to the active-frequency control loop of the energy storage converter.
6. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 1, characterized in that, The frequency recovery control parameters of each energy storage converter are set in the same way so that the steady-state active power distribution relationship of the multi-parallel energy storage power supply system remains unchanged after the frequency recovery control quantity is introduced.
7. The method for frequency recovery and active power oscillation suppression in a multi-parallel energy storage power supply system according to claim 1, characterized in that, Both the frequency recovery control quantity and the oscillation suppression control quantity are generated in the local controller of the energy storage converter. Each energy storage converter collects its own local operating information and the common AC bus voltage.
8. A frequency recovery and active power oscillation suppression device for a multi-parallel energy storage power supply system, applied to each energy storage converter in an isolated distribution network after a disaster, wherein the isolated microgrid includes at least two energy storage converters, and each energy storage converter is connected to a common AC bus via line impedance, characterized in that... The device includes: The acquisition module is used to acquire local operating information and the common AC bus voltage; the local operating information includes the output active power of each energy storage converter; A construction module is used to construct common physical variables based on the common AC bus voltage, wherein the common physical variables are used to characterize the deviation of the common AC bus frequency from the rated frequency; The generation module is used to generate a frequency recovery control quantity based on the common physical variables, and the frequency recovery control quantity is used to compensate for the steady-state deviation of the common AC bus frequency. The extraction module is used to extract the oscillation component in the output active power of the energy storage converter itself, and generate an oscillation suppression control quantity based on the oscillation component. The oscillation suppression control quantity is used to suppress the active power oscillation during the parallel operation of multiple energy storage systems. The correction module is used to introduce the frequency recovery control quantity and the oscillation suppression control quantity into the active-frequency control loop of the energy storage converter to correct the output angular frequency and voltage reference phase angle of the energy storage converter. The control module is used to synthesize a three-phase voltage reference signal based on the corrected voltage reference phase angle and the amplitude of the internal electromotive force of the energy storage converter, and to control the corresponding energy storage converter to output electrical energy.
9. A computer storage medium, characterized in that, The computer storage medium stores a plurality of instructions adapted for loading by a processor and executing the steps of the method as described in any one of claims 1 to 7.
10. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method as described in any one of claims 1 to 7.