A grid-forming optical storage system and a method for verifying a grid-forming optical storage system

Abstract

The application discloses a network-constructed optical storage system and a verification method thereof. The network-constructed optical storage system comprises at least two synchronous generators, the at least two synchronous generators are connected in parallel to a common coupling point, the common coupling point is further connected with at least two parallel loads, the two parallel loads are connected to a power grid, and a control module comprises an active-power regulating module and a reactive-voltage regulating module. A first result output by the active-power regulating module is used for PWM modulation of the at least two synchronous generators, and a second result output by the reactive-voltage regulating module is used for controlling output voltages of the at least two synchronous generators. The active-power regulating module calculates the first result by increasing a control algorithm containing a mutual damping term and an electromagnetic power compensation term. The control module is used for controlling the at least two synchronous generators, and solves the technical problem that multiple grid-connected generators in the related art oscillate in power frequency under multiple working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power grid control, in particular to a grid-forming photovoltaic storage system and a verification method of the grid-forming photovoltaic storage system. BACKGROUND

[0002] Under the development background of implementing the "double carbon" goal and building a new power system, new energy power generation represented by photovoltaic and wind power is the current development focus, and the power electronic equipment connected by new energy cannot provide necessary inertia support and damping support for the power grid, so that the power grid presents a highly power electronic characteristic. Under the background of accelerating energy transformation, China's new energy power generation will develop rapidly, and the new power system has become one of the main development trends of the power industry, and its healthy and stable development is the basis for ensuring the safe and stable operation of the power system and the inevitable result of the optimization and transformation of energy structure.

[0003] In order to ensure the implementation of the "carbon neutral" goal, ensure energy security, and grid-forming control technology can effectively solve the problem of low inertia and weak damping of the new power system, but its own oscillation characteristics of traditional motor may cause power frequency oscillation phenomenon.

[0004] In order to effectively respond to the overall low inertia and weak damping characteristics of the power system, the virtual synchronous generator can effectively simulate the inertia and damping characteristics of the synchronous generator, so as to have the ability to provide certain inertia support for the power grid.

[0005] The grid-forming control improves the system stability by simulating the operating characteristics of the synchronous generator, but also brings the oscillation problem of the synchronous generator. This oscillation characteristic may cause transient active power oscillation and frequency overshoot when the frequency of the power grid side changes or the active set value is adjusted. When multiple grid-forming converters are operated in parallel, due to the weak overcurrent capability of the power electronic equipment, it is difficult to reasonably distribute the virtual inertia and damping, and a series of wideband oscillations may be generated in the internal coupling of the power electronic equipment or the alternating current power grid, and the power angle instability under different types of power grid faults.

[0006] In view of the above problems existing in the related art, no effective solution has been proposed so far. SUMMARY

[0007] The purpose of the present application is to overcome the defects in the prior art, and to provide a grid-forming photovoltaic storage system and a verification method of the grid-forming photovoltaic storage system, so as to solve the technical problem of power frequency oscillation of multiple grid-connected generators when active instruction, power grid frequency and load appear disturbance in the case of large-scale access of new energy in the related art.

[0008] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0009] To achieve the above object, according to one aspect of the present application, a grid-connected optical storage system is provided. The system comprises: at least two synchronous generators connected in parallel to a common coupling point, the common coupling point is also connected with at least two parallel loads, the two parallel loads are respectively connected with a power grid; a control module comprising an active-power regulation module and a reactive-voltage regulation module, the control module is connected with the common coupling point, a first result output by the active-power regulation module is used for PWM modulation of the at least two synchronous generators, a second result output by the reactive-voltage regulation module is used for controlling output voltage of the at least two synchronous generators, wherein the active-power regulation module calculates the first result by increasing a control algorithm comprising a mutual damping term and an electromagnetic power compensation term; the control module is used for controlling the at least two synchronous generators.

[0010] Further, the grid-connected optical storage system further comprises a space vector regulation module connected with the control module and the at least two synchronous generators respectively, used for collecting the first result or the second result output by the control module, and generating a control signal for controlling the synchronous generators according to the first result or the second result.

[0011] Further, each synchronous generator is connected with the common coupling point through a branch comprising a first filter inductance, a filter capacitance and a second filter inductance.

[0012] Further, one end of the parallel load is connected with the power grid through a grid-connected impedance, and the other end of the parallel load is connected with the common coupling point.

[0013] Further, the active-power regulation module comprises: an active-power deviation calculation branch, used for receiving active power P ei output by the synchronous generator and reference power P refi , and outputting an angular frequency correction amount according to an electromagnetic power compensation term k1s / s+k2 and a dynamic frequency correction term 1 / ω0; a damping regulation branch, used for receiving the angular frequency deviation and generating a damping signal based on the received angular frequency deviation and a virtual mutual damping factor M i ; an inertia control branch, used for transmitting the received damping signal, the virtual mutual damping factor M i and the angular frequency correction amount to an inertia module to generate a corresponding angular frequency ω i of the synchronous generator; and an integral calculation branch, used for generating the first result through an integral module according to the angular frequency ω i .

[0014] Further, the reactive-voltage regulation module further comprises: a reactive-power regulation branch, used for receiving actual power Q e of the synchronous generator and reference power Q refdetermining a reactive power difference value, and determining a dynamic reactive power adjustment coefficient ω0K s outputting a voltage dynamic adjustment compensation signal, the voltage dynamic adjustment compensation signal being used to stabilize a voltage operating state of the synchronous generator; and a regulator branch, which generates a dynamic control signal for adjusting reactive power by a proportional-integral controller according to a reference voltage V r and an actual voltage V m of the virtual synchronous generator, the dynamic control signal for adjusting reactive power including reactive voltage information of the synchronous generator.

[0015] Further, after the control algorithm is added, a control expression of the active-power adjustment module is:

[0016]

[0017] wherein P refi is an active reference power of the synchronous generator, P ei is an active actual power of the synchronous generator, ω0 is a reference angular frequency of the synchronous generator, ω i and ω j are angular frequencies of the i-th and j-th synchronous generators, k1 and k2 are power compensation factors corresponding to the synchronous generators, J i is an inertia coefficient, N is a quantity corresponding to the synchronous generators, D pi is a damping coefficient, s is a Laplace operator, and M i is a virtual mutual damping factor.

[0018] To achieve the above object, according to another aspect of the present application, a verification method of a grid-connected optical storage system is provided. The grid-connected optical storage system is the grid-connected optical storage system provided by the present application, and the initial grid-connected optical storage system includes at least two synchronous generators connected to a power grid through at least two loads, and a control module for communication control of the two synchronous generators, wherein the control module does not add a control algorithm. The method includes: building the grid-connected optical storage system by using a predetermined simulation software; building the initial grid-connected optical storage system by using the predetermined simulation software; obtaining active-power change curves corresponding to the grid-connected optical storage system and the initial grid-connected optical storage system, respectively, according to a predetermined working condition; comparing the obtained active-power change curves to obtain a verification result.

[0019] By the present application, a grid-connected optical storage system and a verification method of the grid-connected optical storage system are provided to solve the technical problem of power frequency oscillation of multiple grid-connected generators when active instructions, power grid frequencies and loads are disturbed in the case of large access of new energy in the related art. The reliability and robustness of the grid-connected optical storage system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of a networked optical storage system according to an embodiment of the application;

[0021] Figure 2 is a schematic diagram of another networked optical storage system according to an embodiment of the application;

[0022] Figure 3 is a schematic diagram of a specific structure of a networked optical storage system according to an embodiment of the application;

[0023] Figure 4 is a schematic diagram of an initial networked optical storage system in the prior art;

[0024] Figure 5 is a pole distribution diagram of a networked optical storage system;

[0025] Figure 6 is a control block diagram corresponding to the control algorithm provided by the application;

[0026] Figure 7 is the inertia coefficient J2 and the damping coefficient D of the VSC2 in the conventional control and the control of the application of a networked optical storage system; p2 and the line impedance X e2 are the system pole distribution comparison diagrams when the parameters are increased;

[0027] Figure 8 is a diagram showing the corresponding changes in the networked optical storage system G p1 when M is continuously increased;

[0028] Figure 9 is a flowchart of a verification method of a networked optical storage system according to an embodiment of the application;

[0029] Figure 10 is a diagram showing the active power and frequency fluctuations of the optical storage system when the active power is increased in working condition 1;

[0030] Figure 11 is a diagram showing the active power and frequency fluctuations of the optical storage system when the frequency is decreased in working condition 2;

[0031] Figure 12 is a diagram showing the active power and frequency fluctuations of the optical storage system when the load is suddenly increased in working condition 3;

[0032] Figure 13 is a schematic diagram of an electronic device provided by the application. DETAILED DESCRIPTION

[0033] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] AsFigure 1 As shown in the figure, Figure 1 is a schematic diagram of a grid-forming optical storage system according to an embodiment of the present application, as shown in the figure, the system comprises the following parts: Figure 1

[0035] At least two synchronous generators, at least two synchronous generators are connected in parallel to the common coupling point PCC, and the common coupling point PCC is also connected with at least two parallel loads, and the two parallel loads are respectively connected with the power grid;

[0036] It should be noted that the grid-forming optical storage system can contain two or more than two synchronous generators.

[0037] A control module comprising an active-power regulating module and a reactive-voltage regulating module, the control module is connected with the common coupling point PCC, the first result output by the active-power regulating module is used for PWM modulation of the at least two synchronous generators, and the second result output by the reactive-voltage regulating module is used for controlling the output voltage of the at least two synchronous generators, wherein the active-power regulating module calculates the first result by increasing a control algorithm containing mutual damping terms and electromagnetic power compensation terms. Wherein, the first result is the reference phase angle θ of the synchronous generator, and the second result is E m , used for adjusting the output voltage amplitude of the inverter to match the voltage demand at the common coupling point (PCC). By adjusting E m , the inverter can provide the required reactive power Q e , so as to stabilize the system voltage.

[0038] The present application introduces a control algorithm containing mutual damping terms and electromagnetic power compensation terms, which does not need to collect and calculate the output frequency of each VSC through sensors or phase-locked loops, but only needs to combine ω i for information interaction, realizing the effect of decentralized dynamic mutual damping control, and this method can also be further expanded to a multi-machine system or a multi-area converter parallel, without affecting the normal work of other units or areas, and has good reliability and robustness.

[0039] In an alternative embodiment, as shown in the figure, Figure 2 The grid-forming optical storage system further comprises a space vector regulating module connected with the control module and the at least two synchronous generators respectively, for receiving the first result or the second result output by the control module, and generating a control signal for controlling the synchronous generator according to the first result or the second result.

[0040] ​As mentioned above, the vector control module can precisely control the output voltage and frequency of the inverter through the first result or the second result, while also improving the inverter's efficiency and power quality. Based on this, the entire grid-type photovoltaic-storage system achieves dual closed-loop control of voltage and current.

[0041] In one alternative embodiment, each synchronous generator is connected to a common coupling point via a branch consisting of a first filter inductor, a filter capacitor, and a second filter inductor. One end of the parallel load is connected to the power grid through the grid connection impedance, and the other end of the parallel load is connected to the common coupling point. Figure 3 As shown, Figure 3 The grid-type photovoltaic-storage system in the middle includes two parallel synchronous generators, GFM-VSC1 and GFM-VSC2. Figure 3 The GFM-VSC1 uses a filter inductor L f1 Filter capacitor C f1 and L g1 The common coupling point PCC is connected to the GFM-VSC2, and the other end of the PCC is also connected to a load. The power grid is connected through the grid impedance X. g1 X g2 It connects to the load and then to the common coupling point PCC.

[0042] like Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of an initial grid-type photovoltaic energy storage system in the prior art. In the main circuit structure, L f C f and X g These are the filter inductor, filter capacitor, and grid connection impedance, respectively. The core control part of the grid-connected technology mainly consists of... Figure 4 It consists of an active power-frequency regulation module and a reactive power-voltage regulation module, and its expression is:

[0043]

[0044] Where J is the moment of inertia of the synchronous generator; ω0 is the generator's reference angular velocity; ω is the generator's output angular velocity; T m T e and T d These represent the mechanical torque, electromagnetic torque, and damping torque of the synchronous generator, respectively; D p D is the active damping coefficient. q Q is the reactive power damping coefficient. ref Q is the reactive power reference power of the synchronous generator. e It is the reactive power output of the synchronous generator, V. m It is the actual output voltage of the inverter, V r This is the inverter's voltage reference value, E mThe voltage of the inverter obtained by reactive-voltage calculation. Wherein, the mechanical power expression maintaining the droop characteristic is as follows:

[0045] P m ref -k f (ω-ω0)(2)

[0046] Wherein, k f is the primary frequency modulation coefficient, P ref is the reference power of the active power of the inverter. Considering two grid-connected type optical storage systems, the active power P ei of the i-th VSC output is expressed as:

[0047]

[0048] Wherein, X i is the equivalent impedance of the i-th VSC corresponding line; δ i is the power angle; E i , U g respectively represent the VSC i output voltage and the common point voltage; K i represents the synchronization coefficient.

[0049] The active power P ei of the VSC output is related to the load power P load as shown in the following formula:

[0050]

[0051] According to the linearization processing of the corresponding parameters according to formulas (1)-(4), the following can be obtained:

[0052]

[0053] In this application, the grid-connected type optical storage system containing two parallel VSCs is taken as the analysis object, the power frequency oscillation mechanism of the parallel VSC system during load fluctuation, frequency drop and active instruction change is studied, and the stability change of the system under different virtual inertia and damping changes is considered in combination with the parallel characteristic expression.

[0054] According to formula (5), the expression of the output power of the two parallel units is as follows:

[0055]

[0056] Wherein, the double-machine parallel characteristic expression related to the angular frequency and the active power is:

[0057] D(s)=as 3 +bs 2 +cs+d(7) ​

[0058] The expressions for each parameter in the formula are as follows:

[0059] a=ω0(K1+K2)J1J2

[0060] b=ω0(K1+K2)(D1J2+D2J1)

[0061] c=ω0(K1+K2)D1D2+K1K2(J1+J2)

[0062] d=K1K2(D1+D2) (8)

[0063] From equations (1)-(8), it can be seen that the differences in parallel systems are mainly reflected in the key control parameters J, D, and X. In practice, the power frequency oscillation of a dual-machine parallel system is mainly related to the distribution of the poles of D(s), and the distribution of its poles can reflect the output mode of the system. In equation (7), the system has one negative real root and two conjugate negative roots, where the time-domain expression of the output power of VSC1 can be expressed as:

[0064]

[0065] In the formula, A1 and A2 are constant coefficients of the two modes; λ1 is the negative pole, λ2 is the real part of the conjugate pole, and ω d β represents the imaginary part of the conjugate poles; β is the phase angle. Because of the presence of a sinusoidal component, oscillations will occur under step excitation.

[0066] like Figure 5 As shown, Figure 5 This is a pole distribution diagram of a grid-type photovoltaic-storage system, from... Figure 5 It can be seen that the dual-machine parallel system has a pair of conjugate poles. As J1 increases, the conjugate pole pair gradually moves closer to the imaginary axis, indicating that the system damping decreases, the settling time may become longer, and power oscillations are more likely to occur. As D1 increases, the conjugate pole pair moves to the left and away from the imaginary axis, indicating that the system damping increases and can effectively suppress power oscillations. As X1 increases, the conjugate pole pair moves closer to the real axis with an almost vertical trend, indicating that it only affects the natural oscillation frequency of the system.

[0067] In one optional embodiment, the active power regulation module includes: an active power deviation calculation branch that receives the active power P output by the synchronous generator. ei and reference power P refi Calculate the active power deviation P ei -P refi The active power deviation, combined with the electromagnetic power compensation term k1s / s+k2 and the dynamic frequency correction term 1 / ω0, outputs the angular frequency correction; the damping adjustment branch is used to receive the angular frequency deviation (ω). i -ω0), and based on the angular frequency deviation and the virtual mutual damping factor Mi , generate a damping signal; an inertia control branch for transmitting the received damping signal, a virtual mutual damping factor M i and an angular frequency correction amount to the inertia module 1 / J I S, generate an angular frequency ω i corresponding to the synchronous generator;an integral calculation branch for generating a first result according to the angular frequency ω i through the integral module 1 / S, the first result being a reference phase angle θ, wherein ω i , and the adjustment M i It should be noted that the active-power regulation module containing the mutual damping term and the electromagnetic power compensation term in the present application is applied to the initial network type optical storage system, that is, the initial network type optical storage system only contains the power-power deviation calculation branch, the dynamic frequency correction term 1 / ω0, the integral module D p , the inertia module 1 / J I S, the integral module 1 / S in the optical storage system schematic diagram as shown in Figure 4

[0068] Specifically, due to the differences in the inertia coefficient J i , the damping coefficient D pi , and the line impedance X ei , when there is a load mutation, a frequency drop, and an active instruction, the power-frequency oscillation problem of the connected system is easy to occur, which seriously affects the stability of the system. Therefore, the present application proposes an electromagnetic power and decentralized mutual damping control method, which dynamically adjusts the virtual torque of the VSC by introducing an additional mutual damping term, and reduces the difference between the virtual torques of the VSCs; by introducing an electromagnetic transient process, the system steady-state deviation is not caused, the regulation time of the dynamic process is improved, and the impact power is reduced, so as to suppress the power oscillation problem in the transient process of the system. The control algorithm in the active-power regulation module in Figure 3 , and the specific control block diagram is shown in Figure 6 The red part in the control block diagram is an additional damping term, M i is a virtual mutual damping factor, and after introducing M i , the system can dynamically adjust the virtual torque of each VSC according to the average angular velocity ω output by the different VSCs (voltage source converter), so as to reduce the power oscillation between the VSCs in the system. The blue part is an added electromagnetic red-green compensation term, which is helpful to the system to realize more stable power output in the transient process through dynamic compensation.

[0069] After adding the above control algorithm, the active power control expression of the network type optical storage system is:

[0070]

[0071] wherein P refi is the active reference power of the synchronous generator, P ei is the active actual power of the synchronous generator, ω0is the reference angular frequency of the synchronous generator, ω i , ω j is the angular frequency of the i-th and j-th synchronous generator, k1, k2are the power compensation factors corresponding to the synchronous generator, J i is the inertia coefficient, N is the number corresponding to the synchronous generator, D pi is the damping coefficient, s is the Laplace operator, M i is the virtual mutual damping factor.

[0072] The application introduces a control algorithm, and does not need to collect and calculate the output frequency of each VSC through sensors or phase-locked loops, but only needs to combine ω i of the active ring output of the required grid-forming optical storage system into a group to interact information, so as to realize the effect of decentralized dynamic mutual damping control. The method can also be further expanded to a multi-machine system or a multi-area converter parallel, and does not affect the normal work of other units or areas, and has good reliability and robustness.

[0073] Further analysis of the optimization principle after introducing the control algorithm, at this time, the parallel output power transfer function expression of the grid-forming optical storage system is as follows:

[0074]

[0075] wherein a1~d1are expressed as follows:

[0076]

[0077] According to formula (10)-(12), after introducing the control of the application, the active transfer function of the grid-forming optical storage system changes, and the system characteristic root locus also changes, as shown in Figure 7 , wherein Figure 7 is the inertia coefficient J2, the damping coefficient D p2 and the line impedance X e2 of VSC2 of the grid-forming optical storage system under the conventional control and the control of the application. When the parameters of J2, D p2When the damping factor M increases, the root locus of the system gradually moves away from the imaginary axis, but under the proposed control, the root locus moves relatively further away from the imaginary axis, indicating that the proposed control can increase the damping of the system and speed up the system to reach the steady state; similarly, when the damping factor M increases, the conjugate poles approach the real axis in a nearly vertical trend, indicating that it only affects the natural oscillation frequency of the system. e2 When the damping factor M increases, the conjugate poles approach the real axis in a nearly vertical trend, indicating that it only affects the natural oscillation frequency of the system.

[0078] In summary, after introducing the electromagnetic power and decentralized mutual damping control algorithm, the damping of the network-forming optical storage system can be increased, the dynamic response characteristics can be improved, and the system power frequency oscillation can be effectively suppressed.

[0079] In an alternative embodiment, as shown in the reactive-voltage regulation module shown in Figure 3 , Figure 4 The reactive-voltage regulation module includes: a reactive power regulation branch that determines the reactive power difference based on the actual power Q e of the synchronous generator and the reference power Q ref , and outputs a voltage dynamic regulation compensation signal based on the reactive power difference and the system dynamic reactive regulation coefficient ω0K s , the voltage dynamic regulation compensation signal is used to stabilize the voltage operating state of the synchronous generator; a regulator branch that generates a dynamic control signal for adjusting the reactive power based on the reference voltage V r of the virtual synchronous generator and the actual voltage V m , the dynamic control signal for adjusting the reactive power includes reactive voltage information of the synchronous generator, wherein the reactive voltage information is E m . E m represents the output voltage amplitude of the inverter, and is a key control signal generated by the reactive-voltage regulation control link. Its main function is to adjust the reactive power Q e output by the inverter to stabilize the voltage at the point of common coupling (PCC). By comparing with the reference voltage V r , the output voltage amplitude E m is dynamically adjusted to ensure the stability of the system voltage and power quality. By effectively controlling E m , the system can achieve accurate regulation of the reactive power, maintain the voltage stability of the power grid, and enhance the dynamic response capability and stability of the overall power system.

[0080] In an alternative embodiment, considering the value of the virtual mutual damping factor M, by continuously increasing M, the change of the network-forming optical storage system Gp1 step response is observed, as shown in Figure 8 , Figure 8 is a schematic diagram of the change of the network-forming optical storage system Gp1 step response by continuously increasing M, as shown in Figure 8It can be seen that with the increase of M, the maximum amplitude of the system step response is reduced, but when M reaches a certain degree, the system step response can be large, the steady state time is long and the steady state error can occur. Therefore, the value of M cannot be too large, and the application takes M=10.

[0081] The application is used for electromagnetic power and distributed mutual damping control algorithm acting on the active control loop, increasing the damping of the system from the perspective of the closed-loop characteristic roots of the system without changing the steady-state characteristics of the system, using the distributed damping method, without collecting and calculating the output frequency of each VSC through sensors or phase-locked loops, only needing to output the ω i The information interaction is combined into a group to realize the effect of distributed dynamic mutual damping control, thereby changing the dynamic characteristics of the system. Compared with the traditional method, the application considers the problems of the fluctuation of the output active power of the grid-connected optical storage system and the frequency oscillation, so that the optical storage system can effectively suppress the fluctuation and reduce the oscillation when the active power suddenly changes, the frequency fluctuates and the load changes, and the application can be further expanded to a multi-machine system or a multi-area converter in parallel, without affecting the normal work of other units or areas, and has good reliability and robustness.

[0082] It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a group of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0083] The application embodiment also provides a verification method of a grid-connected optical storage system, Figure 9 is a flowchart of a verification method of a grid-connected optical storage system provided by the application. The grid-connected optical storage system is the above-mentioned grid-connected optical storage system provided by the application, the initial grid-connected optical storage system includes at least two synchronous generators, at least two parallel loads, a power grid and a control module, the at least two synchronous generators are connected with the power grid through the at least two loads, the control module is used for communication control of the two synchronous generators, and no control algorithm is added in the control module, such as Figure 9 As shown, the method comprises:

[0084] S101, building the grid-connected optical storage system through a predetermined simulation software;

[0085] S102, building the initial grid-connected optical storage system through a predetermined simulation software;

[0086] S103, obtaining the active-power change curves corresponding to the grid-connected optical storage system and the initial grid-connected optical storage system respectively according to setting a predetermined working condition;

[0087] S104, compare the active-power change curve obtained and get the verification result.

[0088] The application utilizes Simulink software to build Figure 3 The network type optical storage system shown in the figure, and according to the model, the conventional control and the electromagnetic power based on the distributed mutual damping compensation control are simulated, and the specific parameters are shown in Table 1, and three different working conditions are set to verify:

[0089] Working condition 1: the active instruction increases by 10kW at t=1.6s, and stops increasing at t=3s.

[0090] Working condition 2: the system frequency drops by 0.2Hz at t=1.6s, and returns to normal at t=3s.

[0091] Working condition 3: the system is connected with 20kW load at t=1.6s, and the load is cut off at t=3s.

[0092] Table 1 Simulation parameter table of network type optical storage grid-connected system

[0093]

[0094] The active power and frequency changes of the network type optical storage system under different working conditions are shown in Figure 10 、 11 , (a) and (b) in 12, Figure 10 represent the active power and frequency fluctuation diagram of the optical storage system when the active power increases in working condition 1, Figure 11 represent the active power and frequency fluctuation diagram of the optical storage system when the frequency drops in working condition 2, Figure 12 represent the active power and frequency fluctuation diagram of the optical storage system when the load suddenly increases in working condition 3, there are four curves in each diagram, two solid lines represent the active and frequency change curves of the conventional control of two VSCs, and two dotted lines represent the change curves after the introduction of the control.

[0095] Under the condition of working condition 1, the active instruction increases from 25kW to 35kW at 1.6s, and stops increasing at 3s, from Figure 10 (a) and (b) can be seen that when the active instruction appears disturbance, the conventional control has obvious power frequency oscillation phenomenon, and the introduction of the control proposed in the application can reduce the active power and frequency overshoot of the optical storage system, and effectively alleviate the power frequency oscillation phenomenon.

[0096] Under the condition of working condition 2, the system frequency drops by 0.2Hz at 1.6s, and the frequency returns at 3s; analysis Figure 11(a) It can be seen that when the system frequency is disturbed at 1.6s, the photovoltaic storage system actively supports and increases the active power. The uncompensated output power P1 and P2 oscillate and the response time is long. After compensation, the output power P1 and P2 have no obvious overshoot and no oscillation phenomenon, and the response time is significantly shortened. Figure 11 (b) It can be seen that the frequency response curves f1 and f2 after compensation are significantly better than those before compensation.

[0097] Under operating condition 3, the load suddenly increases by 20kW at 1.6s, and the frequency recovers at 3s; analysis Figure 12 As shown in (a) and (b), when load disturbance occurs, the uncompensated output powers P1 and P2 oscillate and exhibit vibration spikes. After compensation is introduced, the oscillations are significantly reduced and there is no overshoot, but the spikes still exist. The reason may be that the load connected to the photovoltaic storage system is too heavy. At the same time, the frequency response also has corresponding characteristics.

[0098] As can be seen from the above verification method, the grid-type photovoltaic energy storage system provided by the present invention dynamically adjusts the virtual torque of VSC by introducing a control algorithm containing a mutual damping term, thereby reducing the difference between the virtual torques of each VSC; the introduction of electromagnetic transient process will not cause steady-state deviation of the system, but will also improve the adjustment time of the dynamic process and reduce the impact power, thereby suppressing the power oscillation problem in the transient process of the system.

[0099] This invention provides a processor for running a program, wherein the program executes a verification method for a network-type optical storage system according to this invention.

[0100] like Figure 13 As shown, an embodiment of the present invention provides an electronic device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps:

[0101] A grid-type photovoltaic-storage system was built using pre-defined simulation software; an initial grid-type photovoltaic-storage system was also built using the same software; based on pre-defined operating conditions, the active power-power variation curves for both the grid-type photovoltaic-storage system and the initial grid-type photovoltaic system were obtained; the active power-power variation curves were compared, and the verification results were obtained.

[0102] The predetermined operating conditions are any of the following: Operating condition 1: At t=1.6s, the active power is increased to 10kW, and at t=3s, the increase in active power is stopped; Operating condition 2: At t=1.6s, the system frequency drops to 0.2Hz, and at t=3s, the control system frequency returns to the set frequency; Operating condition 3: At t=1.6s, the system receives a 20kW load, and at t=3s, the control load is cut off.

[0103] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0104] Those skilled in the art will appreciate that embodiments of the application can be readily used as a method, apparatus, or computer program product. Accordingly, the application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, magnetic disks, CD-ROMs, optical storage media such as DVD s, etc.) embodying computer program instructions.

[0105] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0106] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0107] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0108] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0109] Memory can include non-persistent memory, Random Access Memory (RAM), and / or non-volatile memory, such as Read Only Memory (ROM) or flash memory, in computer readable medium. Memory is an example of computer readable storage media.

[0110] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0111] It should also be noted that the terms "comprising," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0112] Those skilled in the art will appreciate that embodiments of the present application can be devised for a method, a system, or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer readable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0113] The above embodiments are merely exemplary and are not intended to limit the embodiments. Based on the above description, those skilled in the art can further make modifications and variations to the embodiments. The modifications and variations do not depart from the scope of the embodiments.

Claims

1. A grid-forming optical storage system, characterized by, The networked optical storage system comprises: at least two synchronous generators, the at least two synchronous generators being connected in parallel to a common coupling point, the common coupling point being connected with at least two parallel loads, the two parallel loads being connected with a power grid respectively; a control module comprising an active-power regulating module and a reactive-voltage regulating module, the control module being connected with the common coupling point, a first result output by the active-power regulating module being used for PWM modulation of the at least two synchronous generators, a second result output by the reactive-voltage regulating module being used for control of output voltage of the at least two synchronous generators, wherein the active-power regulating module calculates the first result by increasing a control algorithm containing a mutual damping term and an electromagnetic power compensation term; the control module is used for control of the at least two synchronous generators; The active power regulation module includes: an active power deviation calculation branch, which receives the active power output from the synchronous generator. P ei and reference power P refi And based on the electromagnetic power compensation term and dynamic frequency correction term The output angular frequency correction is provided; the damping adjustment branch is used to receive the angular frequency deviation and, based on the received angular frequency deviation and the virtual cross-damping factor... M i The system generates a damping signal; an inertial control branch is used to process the received damping signal and the virtual cross-damping factor. M i The angular frequency correction amount is transmitted to the inertial module to generate the angular frequency corresponding to the synchronous generator. ω i The integral calculation branch is used to calculate the angular frequency. ω i The first result is generated by the integration module, and the first result is the reference phase angle. θ .

2. The network infrastructure type optical storage system of claim 1, wherein, The networked optical storage system further comprises a space vector regulating module connected with the control module and the at least two synchronous generators respectively, used for receiving the first result or the second result output by the control module, and generating a control signal for control of the synchronous generators according to the first result or the second result. 3.The network-constructing type optical storage system according to claim 1, wherein, Each of the synchronous generators is connected with the common coupling point through a branch composed of a first filter inductance, a filter capacitance and a second filter inductance. 4.The network-constructing type optical storage system according to claim 1, wherein, One end of the parallel load is connected with the power grid through a grid-connection impedance, and the other end of the parallel load is connected with the common coupling point. 5.The network-constructing type optical storage system according to claim 1, wherein, The reactive-voltage regulating module comprises: a reactive power regulating branch, which is regulated in dependence on the actual power of the synchronous generator Q e and a reference power Q ref determining a reactive power difference value, and regulating the reactive power regulating branch in dependence on the reactive power difference value and a system dynamic reactive regulating coefficient ω 0 K s and outputting a voltage dynamic regulating compensation signal, which is used to stabilize the voltage operating state of the synchronous generator a regulator branch, which generates a dynamic control signal for regulating the reactive power of the synchronous generator in dependence on a reference voltage of the synchronous generator V r and an actual voltage V m by means of a proportional-integral controller, which generates a dynamic control signal for regulating the reactive power, which includes reactive voltage information for regulating the synchronous generator. 6.The network-constructing type optical storage system according to claim 1, wherein, After the control algorithm is added, a control expression of the active-power regulating module is: ； wherein, P ref is the active reference power of the synchronous generator, P act is the active actual power of the synchronous generator, ω ref is the reference angular frequency of the synchronous generator, , ω i,j is the angular frequency of the i-th and j-th synchronous generator, k 1、 k 2 is the power compensation factor of the synchronous generator, J i J is the inertia coefficient, N N is the number of the synchronous generators, D is the damping coefficient, s L is the Laplace operator, M i K is the virtual cross-damping factor.

7. A method of verifying a meshed optical storage system according to any one of claims 1 to 6, characterized in that, The method comprises: building the networked optical storage system through a predetermined simulation software; building an initial networked optical storage system through the predetermined simulation software, the initial networked optical storage system containing at least two parallel-connected synchronous generators and a control module, the control module being used for communication control of the at least two synchronous generators, each of the synchronous generators being connected with a power grid through at least one load, the control module comprising an active-power regulating module and a reactive-voltage regulating module, the active-power regulating module not containing a control algorithm of a mutual damping term and an electromagnetic power compensation term; obtaining active-power variation curves corresponding to the networked optical storage system and the initial networked optical storage system respectively according to setting of predetermined working conditions; comparing the obtained active-power variation curves to obtain a verification result. 8.The method of claim 7, wherein, The predetermined working conditions are any of the following: Working condition one: at t=1.6s, the active power is increased to 10kw, and at t=3s, the increase of the active power is stopped; Working condition two: at t=1.6s, the system frequency is decreased to 0.2Hz, and at t=3s, the system frequency is controlled to return to a set frequency; Working condition three: at t=1.6s, a 20kw load is connected to the system, and at t=3s, the load is controlled to be cut off.

9. An electronic device, comprising: An apparatus, including one or more processors and memory storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the method of any of claims 7-8.

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