Network construction type optical storage system and verification method of network construction type optical storage system

Abstract

The invention discloses a network construction type optical storage system and a verification method of the network construction type optical storage system. The network construction type 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, and the two parallel loads are connected into a power grid; the control module comprises an active power regulation module and a reactive power-voltage regulation module, a first result output by the active power regulation module is used for PWM modulation of the at least two synchronous generators, and a second result output by the reactive power-voltage regulation module is used for controlling output voltages of the at least two synchronous generators, the active-power regulation module calculates a first result by adding a control algorithm comprising a mutual damping item and an electromagnetic power compensation item; and the control module is used for controlling the at least two synchronous generators, so that the technical problem of power frequency oscillation of a plurality of grid-connected generators under various working conditions in the prior art is solved.

Description

Technical Field

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

[0002] In the context of 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 to new energy cannot provide the necessary inertia support and damping support for the power grid, making the power grid highly power electronic. In the context of accelerating energy transformation, my country's new energy power generation will develop rapidly, and the new power system has become one of the main development trends in the power industry. Its healthy and stable development is the basis for ensuring the safe and stable operation of the power system, and it is also the inevitable result of the optimization and transformation of the energy structure.

[0003] While ensuring the implementation of energy security and grid-based control technology, it can effectively solve the problems of low inertia and weak damping in new power systems. However, it has the oscillation characteristics of traditional motors and may cause power frequency oscillation.

[0004] In order to effectively cope with 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 that it has the ability to provide a certain inertia support for the power grid.

[0005] Grid-type control improves system stability by simulating the operating characteristics of synchronous generators, but it also brings about the oscillation problem of synchronous generators. This oscillation characteristic may cause transient active power oscillation and frequency overshoot problems when the grid-side frequency changes or the active power set value is adjusted. When multiple grid-type converters are operated in parallel, due to the weak overcurrent capability of power electronic equipment, it is difficult to reasonably allocate virtual inertia and damping. A series of wide-band oscillations may be generated within the power electronic equipment or coupled with the AC grid, as well as power angle instability under different types of grid faults.

[0006] Currently, no effective solution has been proposed for the above-mentioned problems existing in the related technologies. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects in the prior art and provide a grid-connected photovoltaic storage system and a verification method for the grid-connected photovoltaic storage system to solve the technical problem in the related art that when a large amount of new energy is connected, multiple grid-connected generators experience power frequency oscillation when active power instructions, grid frequency and load are disturbed.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a grid-type photovoltaic storage system is provided. The system includes: at least two synchronous generators, at least two synchronous generators are connected in parallel to a common coupling point, the common coupling point is also connected to at least two parallel loads, and the two parallel loads are respectively connected to the power grid; a control module, including an active-power regulation module and a reactive-voltage regulation module, the control module is connected to the common coupling point, the first result output by the active-power regulation module is used for PWM modulation of at least two synchronous generators, and the second result output by the reactive-voltage regulation module is used to control the output voltage of at least two synchronous generators, wherein the active-power regulation module calculates the first result by adding a control algorithm including a mutual damping term and an electromagnetic power compensation term; the control module is used to control at least two synchronous generators.

[0010] Furthermore, the grid-type photovoltaic storage system also includes a space vector regulation module, which is connected to the control module and at least two synchronous generators, and is used to receive the first result or the second result output by the control module, and generate a control signal for controlling the synchronous generator based on the first result or the second result.

[0011] Furthermore, each synchronous generator is connected to the common coupling point through a branch consisting of a first filter inductor, a filter capacitor and a second filter inductor.

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

[0013] Furthermore, the active power regulation module includes: an active power deviation calculation branch, receiving the active power P output by the synchronous generator ei And the reference power P refi , and output the angular frequency correction according to the electromagnetic power compensation term k1s / s+k2 and the dynamic frequency correction term 1 / ω0; the damping adjustment branch is used to receive the angular frequency deviation, and based on the received angular frequency deviation and the virtual mutual damping factor M i , generating a damping signal; the inertial control branch is used to receive the damping signal and the virtual mutual damping factor M i And the angular frequency correction is transmitted to the inertial module to generate the angular frequency ω corresponding to the synchronous generator i ; Integral calculation branch, used according to the angular frequency ω i A first result is generated by the integration module, where the first result is a reference phase angle θ.

[0014] Furthermore, the reactive power-voltage regulation module further includes: a reactive power regulation branch, based on the actual power Q of the synchronous generator e and reference power Q ref, determine the reactive power difference, and based on the reactive power difference and the system dynamic reactive power adjustment coefficient ω0K s , output voltage dynamic adjustment compensation signal, voltage dynamic adjustment compensation signal is used to stabilize the voltage operation state of the synchronous generator; regulator branch, according to the reference voltage V r And the actual voltage V m , a dynamic control signal for adjusting reactive power is generated through a proportional-integral controller, and the dynamic control signal for adjusting reactive power includes adjusting reactive voltage information of the synchronous generator.

[0015] Furthermore, after adding the control algorithm, the control expression of the active power regulation module is:

[0016]

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

[0018] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a verification method for a grid-type photovoltaic storage system is provided. The grid-type photovoltaic storage system is the above-mentioned grid-type photovoltaic storage system provided by the present invention. The initial grid-type photovoltaic storage system includes at least two synchronous generators connected to the power grid through at least two loads, and the control module is used to communicate and control the two synchronous generators. No control algorithm is added to the control module. The method includes: building a grid-type photovoltaic storage system through predetermined simulation software; building an initial grid-type photovoltaic storage system through predetermined simulation software; according to setting predetermined working conditions, respectively obtaining the active-power change curves corresponding to the grid-type photovoltaic storage system and the initial grid-type optical output system; comparing the obtained active-power change curves, and obtaining verification results.

[0019] This application provides a grid-type photovoltaic storage system and a verification method for the grid-type photovoltaic storage system to solve the technical problem in the related art that when a large number of new energy sources are connected, multiple grid-connected generators experience power frequency oscillation when active power instructions, grid frequency, and loads are disturbed. This achieves the effect of improving the reliability and robustness of the grid-type photovoltaic storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a network-type photovoltaic storage system provided according to an embodiment of the present application;

[0021] Figure 2 is a schematic diagram of another grid-type photovoltaic storage system provided according to an embodiment of the present application;

[0022] Figure 3 is a specific structural diagram of a network-type photovoltaic storage system provided according to an embodiment of the present application;

[0023] Figure 4 It is a structural schematic diagram of an initial grid-forming type optical storage system in the prior art;

[0024] Figure 5 This is the pole distribution diagram of the grid-type photovoltaic storage system;

[0025] Figure 6 is a schematic diagram of a control block diagram corresponding to the control algorithm provided in this application;

[0026] Figure 7 The conventional control of the grid-type photovoltaic storage system and the inertia coefficient J2 and damping coefficient D in the VSC2 controlled by the present invention are p2 and line impedance X e2 Schematic diagram of the comparison of system pole distribution when the parameters increase;

[0027] Figure 8 In order to continuously increase M, a network-type photovoltaic storage system G is constructed. p1 Schematic diagram of the changes corresponding to the step;

[0028] Fig. 9 It is a flow chart of a verification method of a networked optical storage system provided in an embodiment of the present application;

[0029] Fig.10 Schematic diagram of active power and frequency fluctuation of the PV storage system when active power is increased in working condition 1;

[0030] Fig.11 The active power and frequency fluctuation diagram of the photovoltaic storage system when the frequency drops in working condition 2;

[0031] Fig.12 The schematic diagram of the fluctuation of active power and frequency of the photovoltaic energy storage system when the load suddenly increases under working condition 3;

[0032] Fig.13 A schematic diagram of an electronic device provided for this application. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below through the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, Figure 1 is a schematic diagram of a networked optical storage system provided according to an embodiment of the present application, such as Figure 1 As shown, the system includes the following parts:

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

[0036] It should be noted that the grid-type photovoltaic storage system may include two or more synchronous generators.

[0037] The control module includes an active power regulation module and a reactive power voltage regulation module. The control module is connected to a common coupling point PCC. The first result output by the active power regulation module is used for PWM modulation of at least two synchronous generators. The second result output by the reactive power voltage regulation module is used to control the output voltage of at least two synchronous generators. The active power regulation module calculates the first result by adding a control algorithm including a mutual damping term and an electromagnetic power compensation term. The first result is a reference phase angle θ corresponding to the synchronous generator, and the second result is E m , which is used to adjust the output voltage amplitude of the inverter to match the voltage requirement at the point of common coupling (PCC). m , the inverter can provide the required reactive power Q e , thereby stabilizing the system voltage.

[0038] This application introduces a control algorithm including mutual damping terms and electromagnetic power compensation terms. It does not need to collect and calculate the output frequency of each VSC through sensors or phase-locked loops. It only needs to convert the ω output of the active loop of the required grid-type photovoltaic storage system into i They are combined into a group to interact with each other and realize the distributed dynamic mutual damping control effect. This method can also be further expanded to multi-machine systems or multi-region converters in parallel without affecting the normal operation of other units or regions, and has good reliability and robustness.

[0039] In an alternative embodiment, Figure 2 As shown, the grid-type photovoltaic storage system also includes a space vector regulation module, which is connected to the control module and at least two synchronous generators, for receiving the first result or the second result output by the control module, and generating a control signal for controlling the synchronous generator based on the first result or the second result.

[0040] As mentioned above, the vector regulation module can accurately control the output voltage and frequency of the inverter through the first result or the second result, while also improving the efficiency and power quality of the inverter. On this basis, the entire grid-type photovoltaic storage system realizes dual closed-loop control of voltage and current.

[0041] In an optional embodiment, each synchronous generator is connected to the common coupling point through 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 grid through a grid impedance, and the other end of the parallel load is connected to the common coupling point. Figure 3 As shown, Figure 3 The grid-connected photovoltaic storage system includes two parallel synchronous generators GFM-VSC1 and GFM-VSC2. Figure 3 In GFM-VSC1, the filter inductor L f1 、Filter capacitor C f1 and L g1 Connected to the common coupling point PCC, GFM-VSC2 is the same, the other end of PCC is also connected to the load, the grid Grid through the grid impedance X g1 , X g2 Connected to the load and then connected to the common coupling point PCC.

[0042] like Figure 4 As shown, Figure 4 The schematic diagram of the structure of the initial grid-type photovoltaic storage system in the prior art. In the main circuit structure, L f , C f and X g They are filter inductance, filter capacitance and grid impedance. Among them, the core control part of the grid-building technology is mainly composed of Figure 4 It consists of an active-frequency regulation module and a reactive-voltage regulation module, and its expression is:

[0043]

[0044] Where J is the moment of inertia of the synchronous generator; ω0 is the reference angular velocity of the generator; ω is the output angular velocity of the generator; T m 、T e and T d are the mechanical torque, electromagnetic torque and damping torque of the synchronous generator respectively; D p is the active damping coefficient, D q is the reactive damping coefficient, Q ref is the reactive reference power of the synchronous generator, Q e is the reactive output power of the synchronous generator, V m is the actual output voltage of the inverter, V r is the voltage reference value of the inverter, E mThe voltage of the inverter is obtained by reactive power-voltage calculation. The mechanical power expression to maintain the droop characteristic is as follows:

[0045] P m =P ref -k f (ω-ω0)(2)

[0046] Among them, k f is the primary frequency modulation coefficient, P ref is the reference power of the inverter active power. Considering the two-unit grid-type photovoltaic storage parallel system, the i-th VSC outputs active power P ei The expression is:

[0047]

[0048] Among them, X i is the equivalent impedance of the line corresponding to the i-th VSC; δ i is the power angle; E i , U g Respectively represent VSC i Output voltage and common point voltage; K i Represents the synchronization coefficient.

[0049] VSC output active power P ei With load power P load The relationship is shown in the following formula:

[0050]

[0051] According to equations (1)-(4), the corresponding parameters are linearized to obtain:

[0052]

[0053] In this application, a grid-connected photovoltaic storage system consisting of two VSCs in parallel is taken as the analysis object. The power-frequency oscillation mechanism of the parallel VSC system during load fluctuations, frequency drops and active power command changes is studied. Combined with the parallel characteristic expression, the stability changes of the system under different virtual inertia and damping changes are considered.

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

[0055]

[0056] Among them, the characteristic expressions of the two-machine parallel connection related to angular frequency and active power are:

[0057] D(s)=as 3 +bs 2 +cs+d(7)

[0058] In the formula, the expressions of each parameter 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 of parallel systems are mainly reflected in the key control parameters J, D and X. In actual situations, the power frequency oscillation of the dual-machine parallel system is mainly related to the distribution of the D(s) poles, 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, and the time domain expression of the VSC1 output power can be expressed as:

[0064]

[0065] Where A1 and A2 are constant coefficients of the two modes; λ1 is the negative pole, λ2 is the real part of the conjugate pole, ω d is the imaginary part of the conjugate pole; β is the phase angle. Because of the presence of sinusoidal components, oscillation will occur under step excitation.

[0066] like Figure 5 As shown, Figure 5 is the pole distribution diagram of the grid-type photovoltaic storage system, Figure 5 It can be seen that there is a pair of conjugate poles in the dual-machine parallel system. With the increase of J1, the conjugate pole pair gradually approaches the imaginary axis, indicating that the system damping decreases, the adjustment time may become longer, and power oscillation is prone to occur; with the increase of D1, 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 oscillation; with the increase of X1, the conjugate pole pair approaches the real axis almost vertically, indicating that it only affects the natural oscillation frequency of the system.

[0067] In an optional embodiment, the active power regulation module includes: an active power deviation calculation branch, receiving the active power P output by the synchronous generator ei And the reference power P refi , calculate the active power deviation P ei -P refi , the active power deviation is combined with the electric k1s / s+k2 magnetic power compensation term and the dynamic frequency correction term 1 / ω0 to output the angular frequency correction value; 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 , generating a damping signal; the inertial control branch is used to receive the damping signal and the virtual mutual damping factor M i And the angular frequency correction is transmitted to the inertial module 1 / J I S, generates the angular frequency ω corresponding to the synchronous generator i ; Integral calculation branch, used according to the angular frequency ω i The first result is generated by the integration module 1 / S, and the first result is the reference phase angle θ, where ω i Reaction and regulation i It should be noted that the active power regulation module of the control algorithm including the mutual damping term and the electromagnetic power compensation term of the present application is not applied in the initial grid-type photovoltaic storage system, that is, the initial grid-type photovoltaic storage system only includes the following Figure 4 The power deviation calculation branch in the schematic diagram of the photovoltaic storage system shown in the figure, the dynamic frequency correction term 1 / ω0, the integration module D p , inertial module 1 / J I S, integration module 1 / S.

[0068] Specifically, due to the inertia coefficient J of each converter i , damping coefficient D pi , line impedance X ei There are differences. When there are sudden load changes, frequency drops and active power instructions, the parallel system is prone to power frequency oscillation problems, which seriously affect the stability of the system. To this end, this application proposes a control method that takes electromagnetic power and distributed mutual damping into consideration. By introducing additional mutual damping terms, the VSC virtual torque is dynamically adjusted to narrow the gap between the virtual torques of each VSC. The introduction of electromagnetic transient processes will not cause system steady-state deviations, but will also improve the adjustment time of the dynamic process, and can also reduce impact power, thereby suppressing power oscillation problems in the system transient process. Introducing the block diagram of electromagnetic power and distributed mutual damping control, see for details. Figure 3 The control algorithm in the active power regulation module is shown in the specific control block diagram. Figure 6 As shown, the red part of the control block diagram adds a damping term, M i is the virtual mutual damping factor, and M is introduced i After that, the system can dynamically adjust the virtual torque of each VSC according to the average angular velocity ω output by different VSCs (voltage source converters) to reduce the power oscillation between the VSCs in the system. The blue part is the added electromagnetic red and green compensation item, which helps the system achieve a smoother power output during transient processes through dynamic compensation.

[0069] After adding the above control algorithm, the active power control expression of the grid-connected photovoltaic storage system is:

[0070]

[0071] Among them, P refi is the active reference power of the synchronous generator, P ei is the active power of the synchronous generator, ω0 is the reference angular frequency of the synchronous generator, ω i ,ω j is the angular frequency of the i-th and j-th synchronous generators, k1 and k2 are the power compensation factors corresponding to the synchronous generators, and J i is the inertia coefficient, N is the number of synchronous generators, D pi is the damping coefficient, s is the Laplace operator, M i is the virtual mutual damping factor.

[0072] By introducing a control algorithm, this application does not need to collect and calculate the output frequency of each VSC through sensors or phase-locked loops, but only needs to convert the ω output of the active loop of the required grid-type photovoltaic storage system into i They are combined into a group to interact with each other and realize the distributed dynamic mutual damping control effect. This method can also be further expanded to multi-machine systems or multi-region converters in parallel without affecting the normal operation of other units or regions, and has good reliability and robustness.

[0073] Further analysis of the optimization principle after the introduction of the proposed control algorithm shows that the parallel output power transfer function expression of the grid-type photovoltaic storage system is as follows:

[0074]

[0075] Among them, the expressions of a1~d1 are as follows:

[0076]

[0077] According to equations (10)-(12), after the control of the present invention is introduced, the active power transfer function of the grid-connected photovoltaic storage system changes, and the corresponding system characteristic root locus also changes, such as Figure 7 As shown, Figure 7 The conventional control of the grid-type photovoltaic storage system and the inertia coefficient J2 and damping coefficient D in the VSC2 controlled by the present invention are p2 and line impedance X e2 Schematic diagram of the comparison of system pole distribution when the parameters increase. When J2 increases, the root loci of the system gradually approach the imaginary axis when using conventional control and the control of the present invention. In contrast, the poles of the control of the present invention are relatively far away from the imaginary axis and even farther away from the real axis, indicating that the control proposed by the present invention can increase the damping of the system and speed up the stability of the system. When D p2When X increases, the root locus of the system gradually moves away from the imaginary axis, but under the proposed control, its root locus is relatively farther away from the imaginary axis, indicating that the control proposed by the present invention can increase the damping of the system and accelerate the speed at which the system reaches a steady state; similarly, when X e2 When it increases, the conjugate pole pair approaches the real axis almost vertically, indicating that it only affects the natural oscillation frequency of the system.

[0078] In summary, the introduction of electromagnetic power and distributed mutual damping control algorithm can increase the damping of the grid-type photovoltaic storage system, improve the dynamic response characteristics, and effectively suppress the power-frequency oscillation of the system.

[0079] In an alternative embodiment, Figure 3 , Figure 4 The reactive-reactive-voltage regulation module shown in FIG. 1 includes: a reactive power regulation branch, based on the actual power Q of the synchronous generator e and reference power Q ref , determine the reactive power difference, and based on the reactive power difference and the system dynamic reactive power adjustment coefficient ω0K s , output voltage dynamic adjustment compensation signal, voltage dynamic adjustment compensation signal is used to stabilize the voltage operation state of the synchronous generator; regulator branch, according to the reference voltage V r And the actual voltage V m , a dynamic control signal for adjusting reactive power is generated by a proportional-integral controller, and the dynamic control signal for adjusting reactive power includes adjusting the 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 the key control signal generated by the reactive-voltage regulation control link. Its main function is to adjust the reactive power Q output by the inverter. e , to stabilize the voltage at the point of common coupling (PCC). r Comparison, dynamically adjust the output voltage amplitude E m , ensuring the stability of system voltage and power quality. By effectively controlling E m The system can achieve precise regulation of 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 optional embodiment, considering the value of the virtual mutual damping factor M, by continuously increasing M, the change of the step response of the grid-type photovoltaic storage system Gp1 is observed, as shown in detail. Figure 8 As shown, Figure 8 To continuously increase M, the schematic diagram of the corresponding step change of the grid-type photovoltaic storage system Gp1 is constructed, as shown in Figure 8It can be seen that as M increases, the maximum amplitude of the system step response decreases, but when M reaches a certain level, the system step response may become larger, the time to reach steady state becomes longer, and steady-state error may occur. Therefore, the value of M cannot be too large, and the present invention takes M=10.

[0081] The present invention adopts electromagnetic power and distributed mutual damping control algorithm to act on the active control loop. On the basis of not changing the steady-state characteristics of the system, the damping of the system is increased from the perspective of the closed-loop characteristic root of the system. By using the distributed damping method, it is not necessary to collect and calculate the output frequency of each VSC through sensors or phase-locked loops. It is only necessary to calculate the ω output of the active loop of the required grid-type photovoltaic storage system. i Combined into a group for information exchange, the distributed dynamic mutual damping control effect is realized, which will change the dynamic characteristics of the system. Compared with other traditional methods, the present invention takes into account the fluctuation of active power output and frequency oscillation of the grid-type photovoltaic storage system, so that the photovoltaic storage system can effectively suppress fluctuations and reduce oscillations when active power suddenly changes, frequency fluctuates and load changes occur. Moreover, the invention can be further expanded to a multi-machine system or multi-region converter parallel connection without affecting the normal operation of other units or regions, and has good reliability and robustness.

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

[0083] The present application also provides a verification method for a networked optical storage system. Fig. 9 It is a flow chart of a verification method of a grid-type photovoltaic storage system provided in an embodiment of the present application. The grid-type photovoltaic storage system is the above-mentioned grid-type photovoltaic storage system provided in the present application. The initial grid-type photovoltaic 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 to the power grid through at least two loads. The control module is used to communicate and control the two synchronous generators. No control algorithm is added to the control module, such as Fig. 9 As shown, the method includes:

[0084] S101, building a grid-based photovoltaic storage system through a predetermined simulation software;

[0085] S102, constructing an initial grid-forming photovoltaic storage system through predetermined simulation software;

[0086] S103, according to the preset working conditions, respectively obtaining active power-power variation curves corresponding to the grid-forming photovoltaic storage system and the initial grid-forming photovoltaic output system;

[0087] S104, comparing the obtained active power-power variation curves and obtaining a verification result.

[0088] The present invention uses Simulink software to build Figure 3 The grid-type photovoltaic storage system shown in the figure is simulated for conventional control and control based on electromagnetic power and distributed mutual damping compensation according to the model. The specific parameters are shown in Table 1. At the same time, three different working conditions are set for verification:

[0089] Working condition 1: At t=1.6s, the active power command increases by 10kW, and at t=3s, the increase stops.

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

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

[0092] Table 1 Simulation parameters of grid-connected photovoltaic and energy storage system

[0093]

[0094] The active power and frequency changes of the grid-type photovoltaic storage system under different working conditions are as follows: Fig.10 , 11 , as shown in (a) and (b) in 12, Fig.10 The schematic diagram of the active power and frequency fluctuation of the PV storage system when the active power is increased in working condition 1 is shown. Fig.11 The active power and frequency fluctuation diagram of the photovoltaic storage system when the frequency drops in working condition 2 is shown in Figure 2. Fig.12 The active power and frequency fluctuation diagram of the photovoltaic storage system when the load suddenly increases under working condition 3 is shown. There are four curves in each figure. The two solid lines represent the active power and frequency change curves of the two VSCs under conventional control, and the two dotted lines represent the change curves after the control of the present invention is introduced.

[0095] Under working condition 1, the active power command increases from 25kW to 35kW at 1.6s and stops at 3s. Fig.10 (a)(b) It can be seen that when the active power command is disturbed, the conventional control has obvious power-frequency oscillation phenomenon. The introduction of the control proposed in the present invention can reduce the active power and frequency overshoot of the photovoltaic storage system and effectively alleviate the power-frequency oscillation phenomenon.

[0096] Under working condition 2, the system frequency drops by 0.2Hz at 1.6s and recovers at 3s; analysis Fig.11(a) It can be seen that when the system frequency is disturbed at 1.6s, the solar energy storage system actively supports and increases the active power. The uncompensated output power P1 and P2 oscillates and the response time is long. The compensated output power P1 and P2 have no obvious overshoot and no oscillation, and the response time is significantly shortened. Fig.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 working condition 3, the load suddenly increases by 20kW at 1.6s, and the frequency recovers at 3s; analysis Fig.12 (a) (b) shows that when there is a load disturbance, the uncompensated output power P1 and P2 oscillates and has vibration spikes. After the compensation is introduced, the oscillation is significantly weakened 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] Through the above verification method, it can be known that a grid-type photovoltaic storage system provided by the present invention dynamically adjusts the VSC virtual torque and narrows the gap between the virtual torques of each VSC by introducing a control algorithm including a mutual damping term; the introduction of electromagnetic transient process will not cause system steady-state deviation, but also improve the adjustment time of the dynamic process, and can also reduce the impact power, thereby suppressing the power oscillation problem in the system transient process.

[0099] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein when the program is run, a verification method of a networked optical storage system in the present invention is executed.

[0100] like Fig.13 As shown, an embodiment of the present invention provides an electronic device, the device includes a processor, a memory, and a program stored in the memory and executable on the processor, and the processor implements the following steps when executing the program:

[0101] A grid-forming photovoltaic storage system is built through predetermined simulation software; an initial grid-forming photovoltaic storage system is built through predetermined simulation software; according to the set predetermined working conditions, the active power-power variation curves corresponding to the grid-forming photovoltaic storage system and the initial grid-forming optical output system are obtained respectively; the obtained active power-power variation curves are compared and the verification results are obtained.

[0102] The preset working condition is any one of the following: working condition 1: at t=1.6s, the active power is increased to 10kw, and at t=3s, the active power is stopped; working 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; working condition 3: at t=1.6s, the system is connected to a 20kw load, and at t=3s, the load is controlled to be cut out.

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

[0104] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0105] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0106] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

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

[0109] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0110] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be 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 disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0111] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0112] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0113] The above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A network-type solar storage system, characterized in that: include: At least two synchronous generators, at least two of the synchronous generators are connected in parallel to a common coupling point, the common coupling point is connected to at least two parallel loads, and the two parallel loads are respectively connected to a power grid; A control module, comprising an active-power regulation module and a reactive-voltage regulation module, the control module being connected to the common coupling point, a first result output by the active-power regulation module being used for PWM modulation of at least two of the synchronous generators, and a second result output by the reactive-voltage regulation module being used for controlling the output voltages of at least two of the synchronous generators, wherein the active-power regulation module calculates the first result by adding a control algorithm including a mutual damping term and an electromagnetic power compensation term; The control module is used to control at least two of the synchronous generators.

2. The grid-type photovoltaic storage system according to claim 1, characterized in that: The grid-type photovoltaic storage system also includes a space vector regulation module, which is respectively connected to the control module and at least two of the synchronous generators, and is used to receive the first result or the second result output by the control module, and generate a control signal for controlling the synchronous generator based on the first result or the second result.

3. The grid-type photovoltaic storage system according to claim 1, characterized in that: Each of the synchronous generators is connected to the common coupling point through a branch consisting of a first filter inductor, a filter capacitor and a second filter inductor.

4. The grid-type photovoltaic storage system according to claim 1, characterized in that: One end of the parallel load is connected to the power grid via a grid-connected impedance, and the other end of the parallel load is connected to the common coupling point.

5. The grid-type photovoltaic storage system according to claim 1, characterized in that: The active power regulation module comprises: The active power deviation calculation branch receives the active power P output by the synchronous generator. ei And the reference power P refi , and according to the electromagnetic power compensation term And dynamic frequency correction Output angular frequency correction; The damping adjustment branch is used to receive the angular frequency deviation and adjust the damping factor M based on the received angular frequency deviation and the virtual mutual damping factor M. i , generating a damping signal; The inertial control branch is used to receive the damping signal and the virtual mutual damping factor M i and the angular frequency correction value, which is transmitted to the inertial module to generate the angular frequency ω corresponding to the synchronous generator i ; The integral calculation branch is used to calculate the angular frequency ω according to the i The first result is generated by an integration module, and the first result is a reference phase angle θ.

6. The grid-type photovoltaic storage system according to claim 1, characterized in that: The reactive power-voltage regulation module comprises: Reactive power regulation branch, according to the actual power Q of the synchronous generator e and reference power Q ref Determine the reactive power difference, and adjust the reactive power according to the reactive power difference and the system dynamic reactive power adjustment coefficient ω0K s , output voltage dynamic adjustment compensation signal, the voltage dynamic adjustment compensation signal is used to stabilize the voltage operation state of the synchronous generator; regulator branch, according to the reference voltage V r And the actual voltage V m , a dynamic control signal for adjusting reactive power is generated through a proportional-integral controller, and the dynamic control signal for adjusting reactive power includes reactive voltage information for adjusting the synchronous generator.

7. The grid-type photovoltaic storage system according to claim 1, characterized in that: After adding the control algorithm, the control expression of the active power regulation module is: Among them, P refi is the active reference power of the synchronous generator, P ei is the active actual power of the synchronous generator, ω0 is the reference angular frequency of the synchronous generator, ω i ,ω j is the angular frequency of the i-th and j-th synchronous generators, k 1、 k2 is the power compensation factor corresponding to the synchronous generator, J i is the inertia coefficient, N is the number of synchronous generators, D pi is the damping coefficient, s is the Laplace operator, M i is the virtual mutual damping factor.

8. A verification method for a networked optical storage system according to any one of claims 1 to 7, characterized in that: The method comprises: building the grid-type photovoltaic storage system by using predetermined simulation software; The initial grid-forming photovoltaic storage system is constructed by the predetermined simulation software, wherein the initial grid-forming photovoltaic storage system comprises at least two synchronous generators connected in parallel and a control module, wherein the control module is used for communication control of at least two synchronous generators, wherein each synchronous generator is connected to the power grid through at least one load, and wherein the control module comprises an active power regulation module and a reactive power voltage regulation module, wherein the active power module does not comprise a control algorithm for mutual damping terms and electromagnetic power compensation terms; According to the preset working conditions, active power-power variation curves corresponding to the grid-forming photovoltaic storage system and the initial grid-forming photovoltaic output system are obtained respectively; Compare the active power change curves and obtain verification results.

9. A verification method for a networked optical storage system according to claim 10, characterized in that: The predetermined operating condition is any one of the following: Working condition 1: when t=1.6s, the active power is increased to 10kw, and when t=3s, the increase of the active power is stopped; Working condition 2: when t=1.6s, the system frequency drops to 0.2Hz, and when t=3s, the system frequency is controlled to return to the set frequency; Working condition three: at t=1.6s, the system is connected to a 20kw load, and at t=3s, the load is controlled to be cut out.

10. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement a verification method for a networked optical storage system as described in any one of claims 8 to 9.

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