Optical storage all-in-one machine frequency indifference and dynamic mutual damping compound control method

Abstract

The invention belongs to the technical field of optical storage all-in-one machine control, and particularly relates to an optical storage all-in-one machine frequency indifference and dynamic mutual damping compound control method. Comprising the following steps: S1, establishing a mathematical model for parallel connection of multiple virtual synchronous generators; s2, carrying out frequency indifference control, enabling the optical storage all-in-one machines to quickly recover to a rated frequency after load disturbance through a distributed frequency consistency algorithm, and achieving the accurate distribution of the active power of each optical storage all-in-one machine; s3, dynamic mutual damping control is carried out, a dynamic mutual damping item is introduced between the optical storage all-in-one machines, the damping characteristic of the system is enhanced, and the problems of active power overshoot and oscillation caused by load disturbance are restrained; according to the method, two strategies of frequency indifference control and dynamic mutual damping control are combined, under the condition of not depending on communication, the frequency stability and power adjustment of the district micro-grid are ensured, and the dynamic response performance and the disturbance rejection capacity of the system are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated photovoltaic and storage machine control, and in particular relates to a frequency zero-difference and dynamic mutual damping composite control method for an integrated photovoltaic and storage machine. Background Art

[0002] With the development and application of renewable energy technology, the application of photovoltaic and energy storage integrated devices (photovoltaic power generation and energy storage systems) in substation microgrids has become increasingly important. Substation microgrids are an important link between the user end and the distribution network. By integrating photovoltaic and energy storage integrated devices into substation microgrids, it can effectively improve the efficiency of power utilization, reduce the peak-to-valley difference of the power grid, and enhance the stability and reliability of the power grid. In addition, photovoltaic and energy storage integrated devices can provide flexible energy management and scheduling functions to meet the diverse power needs of users, thereby improving the intelligence level of the overall energy system.

[0003] The application of virtual synchronous generator (VSG) control strategy in photovoltaic and energy storage integrated machines is particularly important. Traditional photovoltaic power generation and energy storage systems are prone to frequency fluctuations and voltage instability under load disturbances due to the lack of inertia characteristics of synchronous generators. The VSG control strategy simulates the inertia and damping characteristics of synchronous generators, so that the photovoltaic and energy storage integrated machine has a certain inertial response and adjustment ability, thereby improving the dynamic characteristics and stability of the system. The application of VSG control strategy in the substation microgrid can not only improve the response speed and adjustment ability of the photovoltaic and energy storage integrated machine, but also enhance the stability and anti-disturbance ability of the entire microgrid.

[0004] Although the VSG control strategy can effectively improve the dynamic response characteristics of the photovoltaic and storage integrated machine, the frequency deviation problem still exists in practical applications. In the case of load disturbance, the photovoltaic and storage integrated machine may not be able to accurately recover to the rated frequency, thus affecting the overall stability and operating efficiency of the system. Therefore, it is necessary to adopt a frequency zero-difference control strategy. Frequency zero-difference control introduces precise frequency regulation and active power distribution mechanisms to ensure that the photovoltaic and storage integrated machine can quickly recover to the rated frequency after load disturbance and maintain the stability of the system frequency. At the same time, this control strategy can effectively distribute the active power of each photovoltaic and storage integrated machine to ensure the stable operation of the system under different load conditions.

[0005] In the substation microgrid, relying solely on the frequency zero-difference control strategy cannot completely solve all problems. Load disturbances will not only cause frequency deviations, but also lead to overshoot and oscillation problems of active power. The dynamic mutual damping control method can effectively enhance the damping characteristics of the system and suppress overshoot and oscillation of active power by introducing dynamic mutual damping terms between the photovoltaic and storage integrated machines, thereby improving the dynamic response performance of the system. Combining the frequency zero-difference control and dynamic mutual damping control methods can achieve the dual goals of frequency stability and active power regulation, ensuring the stable operation of the system under various load conditions. In modern power systems, the widespread application of photovoltaic and storage integrated machines and the introduction of VSG control strategies have greatly improved the operating efficiency and stability of the system. However, most of the existing research focuses on the optimization of a single control strategy, and there is little research on the combination of frequency zero-difference control and dynamic mutual damping control. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a frequency-neutral and dynamic mutual damping composite control method for a photovoltaic and storage integrated machine. By combining the two strategies of frequency-neutral control and dynamic mutual damping control, the frequency stability and power regulation of the microgrid in the substation area can be ensured without relying on communication, thereby significantly improving the dynamic response performance and anti-disturbance capability of the system.

[0007] The object of the present invention is achieved by: a frequency-indifferent and dynamic mutual damping composite control method for an integrated optical storage device, comprising the following steps:

[0008] S1. Establish a mathematical model of multiple virtual synchronous generators in parallel;

[0009] S2. Perform frequency error-free control. Through a distributed frequency consistency algorithm, the PV-storage integrated machine can quickly recover to the rated frequency after a load disturbance, and achieve accurate active power distribution of each PV-storage integrated machine.

[0010] S3, dynamic mutual damping control is performed, and dynamic mutual damping terms are introduced between the optical storage integrated devices to increase Strong system Damping characteristics can suppress active power overshoot and oscillation problems caused by load disturbances.

[0011] The step S1 of establishing a mathematical model of multiple virtual synchronous generators in parallel includes:

[0012] In a system with N VSGs, each VSG is connected through a power network. The network is represented by a graph G = (V, E), where V is a set of nodes and E is a set of edges. ij ∈E represents VSG i and VSG j The power lines between

[0013] The active power expression of the i-th VSG is:

[0014]

[0015] Among them, P ni , P i Respectively represent the VSG rated active power and actual output active power; ω N ,ω i Represent the rated angular frequency and virtual angular frequency respectively; J i is the virtual moment of inertia; D pi is the virtual damping coefficient, ω bus is the bus frequency;

[0016] Among them, P i The expression is as follows,

[0017]

[0018] Among them, X ei is the equivalent inductive reactance of the line corresponding to the i-th VSG; δ i is the power angle; U i , U bus Respectively represent VSG i Output voltage and common point voltage; k i For VSG i The coefficient of power angle to output power;

[0019] Power angle δ i The expression is as follows,

[0020]

[0021] Where s is the complex frequency;

[0022] VSG output power P i With load power P load The relationship between them is expressed as follows:

[0023]

[0024] The mathematical model of multi-VSG is obtained as follows:

[0025] Δω i =G oi (s)Δω bus

[0026] ΔPi=-(Jiω N s+Dpiω N )Goi(s)Δωbus

[0027]

[0028] Among them, ΔP iThe change in active power of the i-th VSG; Δω i The change in the angular frequency of the i-th VSG; Δω bus is the change value of bus angular frequency; J i is the virtual moment of inertia of the ith VSG; D pi is the virtual damping coefficient of the ith VSG; G ωi (s) is the transfer function from the angular frequency to active power of the i-th VSG; ΔP load is the change of load power; s is the complex frequency;

[0029] G ωi (s) is,

[0030]

[0031] Among them, k i is the gain factor from the angular frequency change to the active power change of the i-th VSG.

[0032] The step S2 of performing frequency error-free control comprises:

[0033] Calculate the frequency error of each optical storage device.

[0034] e ω =ω n -ω bus

[0035] Among them, ω n is the rated angular frequency, ω bus is the bus frequency;

[0036] Calculate the secondary frequency modulation additional term based on the frequency error,

[0037] ufsec=a·∫eωdt+b·eω

[0038] Among them, a and b are adjustment coefficients;

[0039] Adjust the active power command and set u fsec Input into the active power control loop to achieve accurate active power distribution and frequency recovery.

[0040] P i * =P i +u fsec

[0041] Among them, P i * is the adjusted active power command, P i is the original active power command.

[0042] The step S3 of performing dynamic mutual damping control comprises:

[0043] Calculate the frequency difference between each optical storage integrated machine and other optical storage integrated machines,

[0044] Δω ij =ω i -ω j

[0045] The dynamic mutual damping torque is calculated based on the frequency difference,

[0046]

[0047] Among them, H mi is the virtual mutual damping factor, N is the number of integrated optical storage devices involved in the calculation;

[0048] T Hi Input into the active power control loop to enhance system damping,

[0049] P i ** =P i * -T Hi

[0050] Among them, P i ** is the active power command after dynamic mutual damping control.

[0051] Beneficial effects of the present invention: A frequency-differenceless and dynamic mutual damping composite control method for a photovoltaic-storage integrated machine of the present invention, through step S1, establishes a mathematical model of multiple virtual synchronous generators in parallel; S2, performs frequency-differenceless control, through a distributed frequency consistency algorithm, enables the photovoltaic-storage integrated machine to quickly recover to the rated frequency after a load disturbance, and realizes the precise distribution of active power of each photovoltaic-storage integrated machine; S3, performs dynamic mutual damping control, by introducing dynamic mutual damping terms between photovoltaic-storage integrated machines, enhances the damping characteristics of the system, and suppresses the overshoot and oscillation of active power caused by load disturbance; by combining frequency-differenceless control and dynamic mutual damping control, a new method is formed to ensure the frequency stability and power regulation of the substation microgrid without relying on communication. Frequency-differenceless control can accurately adjust the system frequency to keep it stable under various load change conditions, while dynamic mutual damping control can quickly respond to external disturbances and avoid frequency fluctuations by adaptively adjusting the system damping characteristics. The core advantage of this method is that even in a distributed structure, each microgrid unit can work together to ensure the stability and reliability of the entire system. Through a control strategy that does not rely on communication, the present invention not only simplifies the difficulty of implementing the system, but also greatly improves the dynamic response speed and anti-disturbance capability of the system, enabling it to exhibit excellent performance in a complex and changeable power environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0053] Figure 1 It is a diagram of the improved VSG control system of the integrated optical storage machine.

[0054] Figure 2 This is a parallel structure diagram of multiple optical storage devices.

[0055] Figure 3 It is the control block diagram of frequency error-free control.

[0056] Figure 4 It is the block diagram of dynamic mutual damping control.

[0057] Figure 5 It is the overall structure diagram.

[0058] Figure 6 This is the topology diagram of the optical storage integrated machine. DETAILED DESCRIPTION

[0059] The present invention will be further described below in conjunction with the accompanying drawings.

[0060] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] like Figure 1-6 As shown, a frequency-neutral and dynamic mutual damping composite control method for an integrated optical storage device of the present invention comprises the following steps:

[0063] S1. Establish a mathematical model of multiple virtual synchronous generators in parallel;

[0064] S2. Perform frequency error-free control. Through a distributed frequency consistency algorithm, the PV-storage integrated machine can quickly recover to the rated frequency after a load disturbance, and achieve accurate active power distribution of each PV-storage integrated machine.

[0065] S3. Perform dynamic mutual damping control by introducing dynamic mutual damping terms between the photovoltaic and energy storage devices to enhance the damping characteristics of the system and suppress active power overshoot and oscillation problems caused by load disturbances.

[0066] In order to deeply study the dynamic behavior of the multi-virtual synchronous generator parallel system, a detailed mathematical model was first established. The model not only covers the basic dynamic characteristics of each VSG, but also considers the mutual coupling and power sharing mechanism between the VSGs. By introducing a unified virtual inertia, damping coefficient and voltage regulator parameters, the model can accurately simulate the synchronous operation state of the multi-VSG system under different load conditions. The model ensures that the multi-VSG can stably distribute the load and maintain the voltage and frequency stability of the power grid. In addition, by modeling and analyzing the power balance and phase synchronization between multiple VSGs, the mathematical model provides a theoretical basis for further optimizing the control strategy of the multi-VSG parallel system and improving the overall stability of the system.

[0067] like Figure 1 As shown in the figure, in the multi-virtual synchronous machine parallel system, the photovoltaic storage integrated machine simulates the inertia and damping characteristics of the traditional synchronous generator by adopting the virtual synchronous generator control strategy. The goal of the system is to achieve frequency error-free regulation and dynamic mutual damping control by coordinating the control of each photovoltaic storage integrated machine, thereby improving the stability and dynamic response performance of the system.

[0068] Furthermore, the step S1 of establishing a mathematical model of multiple virtual synchronous generators in parallel includes:

[0069] like Figure 2 As shown in the figure, in a system with N VSGs, each VSG is connected through a power network. The network is represented by a graph G = (V, E), where V is a node set and E is an edge set. Each edge e ij ∈E represents VSG i and VSG j The power lines between

[0070] The active power expression of the i-th VSG is:

[0071]

[0072] Among them, P ni , P i Respectively represent the VSG rated active power and actual output active power; ω N ,ω i Represent the rated angular frequency and virtual angular frequency respectively; J i is the virtual moment of inertia; D pi is the virtual damping coefficient, ω bus is the bus frequency;

[0073] Among them, P i The expression is as follows,

[0074]

[0075] Among them, X ei is the equivalent inductive reactance of the line corresponding to the i-th VSG; δ i is the power angle; U i , U bus Respectively represent VSG i Output voltage and common point voltage; k i For VSG i The coefficient of power angle to output power;

[0076] Power angle δ i The expression is as follows,

[0077]

[0078] Where s is the complex frequency;

[0079] VSG output power P i With load power P load The relationship between them is expressed as follows:

[0080]

[0081] The mathematical model of multi-VSG is obtained as follows:

[0082] Δω i =G oi (s)Δω bus

[0083] ΔPi=-(Jiω N s+Dpiω N )Goi(s)Δωbus

[0084]

[0085] Among them, ΔP i The change in active power of the i-th VSG; Δω i The change in the angular frequency of the i-th VSG; Δω bus is the change value of bus angular frequency; J i is the virtual moment of inertia of the ith VSG; D pi is the virtual damping coefficient of the ith VSG; G ωi (s) is the transfer function from the angular frequency to active power of the i-th VSG; ΔP load is the change of load power; s is the complex frequency;

[0086] G ωi (s) is,

[0087]

[0088] Among them, k i is the gain factor from the angular frequency change to the active power change of the i-th VSG.

[0089] Furthermore, the step S2 of performing frequency error-free control includes:

[0090] like Figure 3 As shown, the frequency error-free control uses a decentralized frequency consistency algorithm to enable the photovoltaic and storage integrated machine to quickly recover to the rated frequency after a load disturbance and achieve accurate distribution of active power of each photovoltaic and storage integrated machine.

[0091] Calculate the frequency error of each optical storage device.

[0092] e ω =ω n -ω bus

[0093] Among them, ω n is the rated angular frequency, ω bus is the bus frequency;

[0094] Calculate the secondary frequency modulation additional term based on the frequency error,

[0095] ufsec=a·∫eωdt+b·eω

[0096] Among them, a and b are adjustment coefficients;

[0097] Adjust the active power command and set u fsec Input into the active power control loop to achieve accurate active power distribution and frequency recovery.

[0098] P i * =P i +u fsec

[0099] Among them, P i * is the adjusted active power command, P i is the original active power command.

[0100] Furthermore, the step S3 of performing dynamic mutual damping control includes:

[0101] like Figure 4 As shown in the figure, dynamic mutual damping control enhances the damping characteristics of the system by introducing dynamic mutual damping terms between the photovoltaic and energy-storage integrated devices, effectively suppressing the active power overshoot and oscillation problems caused by load disturbances.

[0102] Calculate the frequency difference between each optical storage integrated machine and other optical storage integrated machines,

[0103] Δω ij =ω i -ω j

[0104] The dynamic mutual damping torque is calculated based on the frequency difference,

[0105]

[0106] Among them, H mi is the virtual mutual damping factor, N is the number of integrated optical storage devices involved in the calculation;

[0107] T Hi Input into the active power control loop to enhance system damping,

[0108] P i ** =P i * -T Hi

[0109] Among them, P i ** is the active power command after dynamic mutual damping control.

[0110] By combining frequency zero-difference control and dynamic mutual damping control, the present invention can ensure the frequency stability and power regulation of the substation microgrid without relying on communication, and significantly improve the dynamic response performance and anti-disturbance capability of the system.

[0111] In summary, the present invention provides a frequency-difference-free and dynamic mutual damping composite control method for a photovoltaic-storage integrated machine. Through steps S1, a mathematical model of multiple virtual synchronous generators in parallel is established; S2, frequency-difference-free control is performed. Through a distributed frequency consistency algorithm, the photovoltaic-storage integrated machine can quickly recover to the rated frequency after a load disturbance, and the active power of each photovoltaic-storage integrated machine is accurately distributed; S3, dynamic mutual damping control is performed. By introducing dynamic mutual damping terms between photovoltaic-storage integrated machines, the damping characteristics of the system are enhanced, and the active power overshoot and oscillation problems caused by load disturbances are suppressed; by combining frequency-difference-free control and dynamic mutual damping control, a new method is formed to ensure the frequency stability and power regulation of the substation microgrid without relying on communication. Frequency-difference-free control can accurately adjust the system frequency to keep it stable under various load change conditions, while dynamic mutual damping control can quickly respond to external disturbances and avoid frequency fluctuations by adaptively adjusting the system damping characteristics. The core advantage of this method is that even in a distributed structure, each microgrid unit can work together to ensure the stability and reliability of the entire system. Through a control strategy that does not rely on communication, the present invention not only simplifies the difficulty of implementing the system, but also greatly improves the dynamic response speed and anti-disturbance capability of the system, enabling it to exhibit excellent performance in a complex and changeable power environment.

[0112] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0113] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A frequency-neutral and dynamic mutual damping composite control method for an integrated optical storage device, characterized in that: The following steps are involved: S1. Establish a mathematical model of multiple virtual synchronous generators in parallel; S2. Perform frequency error-free control. Through a distributed frequency consistency algorithm, the PV-storage integrated machine can quickly recover to the rated frequency after a load disturbance, and achieve accurate active power distribution of each PV-storage integrated machine. S3. Perform dynamic mutual damping control by introducing dynamic mutual damping terms between the photovoltaic and energy storage devices to enhance the damping characteristics of the system and suppress active power overshoot and oscillation problems caused by load disturbances.

2. A frequency-neutral and dynamic mutual damping composite control method for an integrated optical storage device as claimed in claim 1, characterized in that: The step S1 of establishing a mathematical model of multiple virtual synchronous generators in parallel includes: In a system with N VSGs, each VSG is connected through a power network. The network is represented by a graph G = (V, E), where V is a set of nodes and E is a set of edges. ij ∈E represents VSG i and VSG j The power lines between The active power expression of the i-th VSG is: Among them, P ni , P i Respectively represent the VSG rated active power and actual output active power; ω N ,ω i Represent the rated angular frequency and virtual angular frequency respectively; J i is the virtual moment of inertia; D pi is the virtual damping coefficient, ω bus is the bus frequency; Among them, P i The expression is as follows, Among them, X ei is the equivalent inductive reactance of the line corresponding to the i-th VSG; δ i is the power angle; U i , U bus Respectively represent VSG i Output voltage and common point voltage; k i For VSG i The coefficient of power angle to output power; Power angle δ i The expression is as follows, Where s is the complex frequency; VSG output power P i With load power P load The relationship between them is expressed as follows: The mathematical model of multi-VSG is obtained as follows: Give i =G oi (s)See bus ΔPi=-(Jiω N s+Dpiω N )Goi(s)Δωbus Among them, ΔP i The change in active power of the i-th VSG; Δω i The change in the angular frequency of the i-th VSG; Δω bus is the change value of bus angular frequency; J i is the virtual moment of inertia of the ith VSG; D pi is the virtual damping coefficient of the ith VSG; G ωi (s) is the transfer function from the angular frequency to active power of the i-th VSG; ΔP load is the change of load power; s is the complex frequency; G ωi (s) is, Among them, k i is the gain factor from the angular frequency change to the active power change of the i-th VSG.

3. The frequency-neutral and dynamic mutual damping composite control method of an integrated optical storage device as claimed in claim 1, characterized in that: The step S2 of performing frequency error-free control comprises: Calculate the frequency error of each optical storage device. e ω =ω n -oh bus Among them, ω n is the rated angular frequency, ω bus is the bus frequency; Calculate the secondary frequency modulation additional term based on the frequency error, ufsec=a·∫eωdt+b·eω Among them, a and b are adjustment coefficients; Adjust the active power command and set u fsec Input into the active power control loop to achieve accurate active power distribution and frequency recovery. Q i * =P i +u fsec Among them, P i * is the adjusted active power command, P i is the original active power command.

4. The frequency-neutral and dynamic mutual damping composite control method of an integrated optical storage device as claimed in claim 1, characterized in that: The step S3 of performing dynamic mutual damping control comprises: Calculate the frequency difference between each optical storage integrated machine and other optical storage integrated machines, Give ij =ω i -oh j The dynamic mutual damping torque is calculated based on the frequency difference, Among them, H mi is the virtual mutual damping factor, N is the number of integrated optical storage devices involved in the calculation; T Hi Input into the active power control loop to enhance system damping, P i ** =P i * -T Hi Among them, P i ** is the active power command after dynamic mutual damping control.

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