An energy scheduling method based on dynamic impedance

Abstract

The application discloses a kind of energy scheduling methods based on dynamic impedance, comprising the following steps: S1: real-time acquisition and each inverter in parallel system corresponding grid each phase sequence dynamic impedance;S2: according to each inverter in parallel system corresponding grid each phase sequence dynamic impedance, the safe limit of each inverter in parallel system each phase charge-discharge power is calculated;S3: according to the safe limit of each inverter in parallel system each phase charge-discharge power calculated, adjustment target power distribution.The energy scheduling method based on dynamic impedance proposed in the application can avoid overcurrent problem caused by circulating current, and plays a role in protecting inverter.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and in particular to an energy dispatching method based on dynamic impedance. Background Technology

[0002] With the rapid development of the energy storage industry, residential energy storage products are becoming increasingly popular. More and more users hope to use the parallel inverter solution to expand inverter power and battery capacity. However, parallel expansion of high-power inverters will bring about the problem of parallel circulating current. If the EMS (Energy Management System) does not pay attention to this problem when adjusting the power after grid connection, it may cause overcurrent at the inverter grid port, which will eventually damage the inverter.

[0003] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an energy dispatching method based on dynamic impedance, which can avoid overcurrent problems caused by circulating current and protect the inverter.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention discloses an energy dispatching method based on dynamic impedance, comprising the following steps:

[0007] S1: Real-time acquisition of the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid;

[0008] S2: Based on the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid, calculate the safety limit of the charging and discharging power of each phase of each inverter in the parallel system.

[0009] S3: Adjust the target power allocation based on the calculated safety limits of the charging and discharging power of each phase of each inverter in the parallel system.

[0010] Furthermore, S1 specifically includes:

[0011] S11: Real-time acquisition of voltage data at the input grid terminal and the grid terminal of each inverter, as well as the effective current value of each inverter;

[0012] S12: Based on voltage data and effective current values, obtain the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time.

[0013] Furthermore, S12 specifically includes: calculating the voltage difference between the voltage data at the input grid terminal and the voltage data at the grid terminal of each inverter based on the voltage data at the input grid terminal and the grid terminal of each inverter, and obtaining the dynamic impedance of each phase sequence of the grid corresponding to each inverter in the parallel system in real time based on the ratio of the voltage difference to the effective value of the current.

[0014] Further, S2 includes: calculating the maximum value of the ratio of the dynamic impedance of each inverter phase in the parallel system to the sum of the dynamic impedances of all inverter phases in the parallel system based on the dynamic impedance of each inverter corresponding to a certain phase sequence of the power grid, and dynamically calculating the safety limit of the charging and discharging power of the inverter phase based on the maximum value of the ratio.

[0015] Furthermore, S2 includes, under charging conditions, using formula (1) to dynamically calculate the safety limit of the charging power per phase of each inverter in the parallel system based on the dynamic impedance:

[0016]

[0017] In the formula, For the inverter j The total target charging power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters. j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

[0018] Furthermore, when the inverter is calculated using formula (1), the first... j When the total target charging power is less than 0, then the inverter's first... j The total charging target power is set to 0.

[0019] Furthermore, S2 includes the calculation of the safety limit of the discharge power per phase of each inverter in the parallel system based on the dynamic impedance using formula (2) under the discharge state:

[0020]

[0021] In the formula, For the inverter j The total discharge target power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters.j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

[0022] Further, S1 includes: acquiring the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time, so as to generate an n×m dimensional dynamic impedance matrix, where n is the number of inverters and m is the number of phases of the inverters; S2 calculates the nth phase of the parallel system based on the dynamic impedance matrix. i The first inverter j Safety limits for phase charge and discharge power, among which i ≤ n , j ≤ m .

[0023] In a second aspect, the present invention discloses a computer-readable storage medium storing a computer program, wherein the computer program is configured to be run by a processor to perform the energy dispatching method based on dynamic impedance as described in the first aspect.

[0024] Compared with existing technologies, the beneficial effects of this invention are as follows: The energy dispatching method based on dynamic impedance disclosed in this invention acquires the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time. Then, based on the dynamic impedance, it calculates the safety limit of the charging and discharging power of each phase of each inverter in the parallel system, and adjusts the target power allocation based on the safety limit. This can prevent overcurrent problems caused by circulating current in the parallel operation of inverters, thus protecting the inverters and enabling the energy storage system to operate stably for a long time. Moreover, dynamic impedance matching achieves balanced power distribution among multiple inverters, improving the overall system efficiency. Attached Figure Description

[0025] Figure 1 This is a flowchart of the energy dispatching method based on dynamic impedance disclosed in a preferred embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of an inverter parallel system in a specific embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the path from the grid end to the Backup coupling point of the inverter parallel system in a specific embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the impedance from the grid terminal to the Backup coupling point of the inverter parallel system in a specific embodiment of the present invention;

[0029] Figure 5This is a schematic diagram of the inverter parallel system when the impedances of each line are unbalanced in a specific embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of voltage acquisition in an inverter parallel system in a specific embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram showing the connection between each inverter and each phase of the grid in a specific embodiment of the inverter parallel system of the present invention;

[0032] Figure 8 This is a schematic diagram of the Backup load of the inverter parallel system in a specific embodiment of the present invention. Detailed Implementation

[0033] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0034] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for both fixing and circuit / signal connectivity.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] like Figure 1 As shown, a preferred embodiment of the present invention discloses an energy dispatching method based on dynamic impedance, comprising the following steps:

[0038] S1: Real-time acquisition of the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid;

[0039] S1 includes: acquiring the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time, so as to generate an n×m dynamic impedance matrix, where n is the number of inverters and m is the number of phases of the inverters; S2 calculates the nth phase of the parallel system based on the dynamic impedance matrix. i The first inverter j Safety limits for phase charge and discharge power, among which i ≤ n , j ≤ m .

[0040] Specifically, S1 includes:

[0041] S11: Real-time acquisition of voltage data at the input grid terminal and the grid terminal of each inverter, as well as the effective current value of each inverter;

[0042] S12: Based on voltage data and effective current values, obtain the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time.

[0043] This step S12 specifically includes: calculating the voltage difference between the voltage data at the input grid terminal and the voltage data at the grid terminal of each inverter based on the voltage data at the input grid terminal and the grid terminal of each inverter, and obtaining the dynamic impedance of each phase sequence of the grid corresponding to each inverter in the parallel system in real time based on the ratio of the voltage difference to the effective value of the current.

[0044] In AC systems, impedance itself is a complex number, containing components such as resistance, inductance, and capacitance. Therefore, to obtain more complete impedance information, phase data can be introduced into the measurement. In some embodiments, Kirchhoff's Voltage Law (KVL) or FFT analysis can be used to obtain the phase information of voltage and current. In this case, S11 includes: acquiring the voltage amplitude and phase difference at the input grid terminal and each inverter grid terminal in real time, as well as the effective value and phase of the current of each inverter. Correspondingly, S12 includes: calculating the amplitude and phase angle of the complex impedance based on the voltage amplitude and phase difference at the input grid terminal and each inverter grid terminal, combined with the effective value and phase of the current, thereby obtaining the dynamic impedance containing the real and imaginary parts of the impedance.

[0045] In some embodiments, the dynamic impedance is updated at a frequency of 10-100 times per second, that is, the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid is obtained at a period of 10ms to 100ms.

[0046] To ensure synchronized sampling of voltage and current data from multiple inverters and avoid deviations in dynamic impedance calculation, in some embodiments, a high-precision clock is used to synchronize the voltage and current sampling at the grid end of each inverter, and a sliding window averaging method is used to suppress high-frequency noise.

[0047] S2: Based on the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid, calculate the safety limit of the charging and discharging power of each phase of each inverter in the parallel system.

[0048] Step S2 includes: calculating the maximum value of the ratio of the dynamic impedance of each inverter phase in the parallel system to the sum of the dynamic impedances of all inverter phases in the parallel system based on the dynamic impedance of each inverter corresponding to a certain phase sequence of the power grid; and dynamically calculating the safety limit of the charging and discharging power of the inverter phase based on the maximum value of the ratio.

[0049] In the charging state, the safety limit of the charging power per phase of each inverter in the parallel system is dynamically calculated based on the dynamic impedance using formula (1):

[0050]

[0051] In the formula, For the inverter j The total target charging power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters. j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

[0052] When the inverter is calculated using formula (1), j When the total target charging power is less than 0, then the inverter's first... j The total charging target power is set to 0.

[0053] Under discharge conditions, the safety limit of the discharge power per phase of each inverter in the parallel system is dynamically calculated based on the dynamic impedance using formula (2):

[0054]

[0055] In the formula, For the inverter j The total discharge target power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters. j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

[0056] In formulas (1) and (2) As a dynamic adjustment coefficient, its value ranges from greater than 0 to less than 1.

[0057] In some embodiments, if all inverters are of the first j When the sum of the dynamic impedances of each phase is zero, then the first phase of each inverter is forced to... j The safe limit for phase charge and discharge power is It will also trigger a warning to check the line connection status.

[0058] in, For example, load power can be measured in real time using current and voltage sensors at the off-grid output port, and a low-pass filter can be used to suppress transient fluctuations.

[0059] S3: Adjust the target power allocation based on the calculated safety limits of the charging and discharging power of each phase of each inverter in the parallel system.

[0060] When adjusting the target power allocation, it is necessary to ensure that the total charging and discharging power of the parallel system does not exceed the maximum carrying capacity of the grid side or the load side.

[0061] The energy dispatching method based on dynamic impedance disclosed in the preferred embodiment of the present invention can avoid overcurrent problems caused by circulating current when the inverter is in parallel by real-time monitoring of the dynamic impedance of the system and adjusting the target power based on the dynamic impedance, thereby protecting the inverter and enabling the energy storage system to operate stably for a long time.

[0062] The following detailed description of the energy dispatching method based on dynamic impedance disclosed in the preferred embodiment of the present invention, with reference to specific examples, provides further explanation.

[0063] like Figure 2 The diagram shown is a schematic of the inverter parallel system in this specific example. Each inverter (INV1, INV2, or INV3) has an off-grid output port (Backup) and a grid-connected output port (Grid). When the system is off-grid, the off-grid output ports (Backup) of all inverters (including INV1, INV2, and INV3) are interconnected and share the load. When the system is grid-connected, the relays between the off-grid output port (Backup) and the grid-connected output port (Grid) within each inverter are activated, and all grid-connected output ports (Grid) are connected to the power grid. Figure 2 Only one phase is used as an example; the other two phases are the same.

[0064] Figure 2In the case of a typical application scenario for a parallel inverter system, after the system is in operation, when it is off-grid, only the off-grid output port (Backup) relay is closed to carry off-grid load. This corresponds to the application scenario of the energy dispatching method based on dynamic impedance disclosed in the preferred embodiment of the present invention, which is off-grid parallel operation with load. When connected to the grid, after the phase lock is successful, the grid output port (Grid) relay is closed to interact with the grid and carry out grid-connected charging and discharging.

[0065] refer to Figure 3 In one example, taking a 1kW charging rate per phase for each inverter as an example, the charging power at the inverter end is controllable, ensuring that the power from the backup coupling point of the three inverters (INV1, INV2, INV3) to their respective inverter ends is controlled at 1kW. However, there are three paths from the grid end to the backup coupling point, and the amount of power traversed by each of these three paths cannot be directly determined. Specifically, each of these three paths can be divided into two parts: one part is the internal wiring of the inverter, and the other part is the external wiring connecting the inverter to the grid. (Reference) Figure 4 The impedance of the line from the Backup coupling point to the external port of the inverter is named 'a' (including a1, a2, and a3, where a1 represents the impedance from the Backup coupling point to the INV1 grid terminal, a2 represents the impedance from the Backup coupling point to the INV2 grid terminal, and a3 represents the impedance from the Backup coupling point to the INV3 grid terminal). The impedance of the line from the external port of the inverter to the grid is named 'b' (including b1, b2, and b3, where b1 represents the impedance from the INV1 grid terminal to the input grid terminal, b2 represents the impedance from the INV2 grid terminal to the input grid terminal, and b3 represents the impedance from the INV3 grid terminal to the input grid terminal). Impedance 'a' (including a1, a2, and a3) is the impedance of the internal lines of the inverter, and its value range is fixed and cannot be changed. Impedance 'b' (including b1, b2, and b3) is the impedance of the line from the external port of the inverter to the grid, and the line can be easily changed, so its impedance is not fixed.

[0066] refer to Figure 5 When the impedances of the lines in a parallel system are unbalanced, circulating current will occur. The smaller the impedance, the greater the power passing through. If the impedance of phase a1+b1 corresponding to INV1 is much smaller than that of the other two phases, then circulating current will occur. Figure 5 In this situation, a1 is carrying more power (13kW as shown in the figure). Ideally, a1 can only handle 5kW of power, but now it will handle more than twice that. Meanwhile, a2 and a3 only handle 1kW. With the rated power of a (a1, a2 or a3) at 10kW, although the three a lines can handle up to 30kW in parallel operation, due to the circulating current problem, problems may occur when the total input power is 15kW. This may eventually lead to severe overheating of a1 and ultimately damage to the inverter.

[0067] In an energy storage inverter system, the line impedance from the grid-connected output port (Grid) to the off-grid output port (Backup) includes resistance R, inductance L, and capacitance C. This solution operates at low frequencies, where resistance is dominant; therefore, the effects of inductance L and capacitance C can be ignored. The resistance R of the line impedance from the grid-connected output port (Grid) to the off-grid output port (Backup) is affected by two factors: power output and frequency variation. Specifically, firstly, due to the temperature effect, increased power leads to increased current, Joule heating, and a rise in line temperature, increasing resistance. Secondly, the skin effect occurs; at high frequencies or with large currents, the current concentrates on the conductor surface, reducing the effective cross-sectional area of ​​the line, which also leads to increased resistance. Based on these factors, the inverter's line impedance is not constant during operation but changes in real time according to environmental conditions or power output.

[0068] In a specific embodiment of the present invention, a monitoring method is used to monitor line impedance in real time, and a corresponding adjustment algorithm is used to enable the parallel system to operate safely for a long time, thereby eliminating the safety hazards caused by parallel circulating current problems to the operation of the parallel system.

[0069] First, the impedance matrix is ​​obtained in real time by monitoring the voltage at the input grid terminal and the inverter grid terminal.

[0070] refer to Figure 6 A multiplexer can be added to the circuit section (i.e., Figure 6 The voltage acquisition unit shown collects the voltage at the grid terminal and the grid terminal of each inverter. Additionally, the inverter needs to transmit the RMS current value from the grid port to the EMS (Energy Management System). Using a multiplexer ensures that the voltage sampling data comes from the same acquisition system, reducing errors; the RMS current value can be obtained from the inverter. It should be noted that... Figure 6 The diagram only shows the schematic of a single phase of each inverter. The voltage information obtained includes the grid terminal voltage Vgrid of that phase and the grid terminal voltages V1, V2, and V3 of each inverter in that phase. Each inverter transmits the effective current values ​​I1, I2, and I3 of the grid port to the EMS. The schematic diagrams of other phases are similar.

[0071] Based on the obtained voltage information (voltages at the grid terminal and each inverter's grid terminal), a dynamic impedance matrix can be obtained. This impedance matrix has an order of n×m, where n represents the number of inverters and m represents the number of inverter phases. Each element Rij in the matrix represents the total impedance from the j-th phase inverter terminal of the i-th inverter to the grid terminal. A schematic diagram of the connection between each inverter and each phase of the grid terminal is shown below. Figure 7 As shown in the figure (where the grid-connected output port and the off-grid output port are omitted), the final impedance matrix is ​​shown in Table 1.

[0072] Table 1 Total impedance of each phase of the power grid corresponding to each inverter

[0073]

[0074] In the table above, INV1, INV2, and INV3 represent the 1st, 2nd, and 3rd inverters, respectively; L1, L2, and L3 represent the 1st, 2nd, and 3rd phases of the power grid, respectively; Rij represents the total impedance from the inverter terminal of the jth phase of the i-th inverter to the grid terminal; Vgrid_j represents the grid terminal voltage of the jth phase; Vinvi_j represents the inverter grid terminal voltage of the jth phase of the i-th inverter; and Iinvi_j represents the effective value of the current in the jth phase of the i-th inverter.

[0075] The impedance matrix described above can be updated in real time based on the voltage information and the effective value of the current obtained in real time.

[0076] Second, energy dispatch is performed using an impedance matrix.

[0077] This step involves adding limits to the total charging and discharging power of each phase based on the impedance matrix, building upon the existing EMS dispatching scheme. Limiting fine-tuning; that is, calculating the safe limit of charging and discharging power for each phase based on the impedance matrix, and then adjusting the distribution of target power based on the safe limit, i.e., energy dispatching.

[0078] refer to Figure 8 In the charging state, taking one phase as an example, assume the total target charging power for that phase is... Target charging power and off-grid output port (Backup) load The sum is ( That is, the total power at the Backup coupling point), and the single-phase rated protection power point of each inverter is... ,if This indicates an overcurrent risk, and an additional limiting strategy needs to be added to the target power of each phase to obtain... The maximum value is To ensure system security, it is necessary to ensure ,Right now The final result is: This means that there is an upper limit to the total target charging power of this phase. If the value is negative, it is treated as 0. The target charging power for each phase can be calculated using this method.

[0079] In the discharge state, taking one phase as an example, let's assume the total discharge target power of that phase is... Discharge target power and off-grid output port (Backup) load The difference is ( That is, the total power at the backup coupling point), if A negative value (where power is negative when it flows from the grid into the system and positive when it flows from the system into the grid; i.e., power is negative during charging and negative during discharging) indicates that the load power is too high, and no further processing is necessary; similar to the charging principle, obtain... The maximum value is To protect the inverter's grid side, it is necessary to ensure ,Right now That is, the upper limit of the target discharge power of this phase is The above steps, calculated and processed in real time during operation, ensure that the power at the machine's mains outlet remains within the protection range. The target discharge power for each phase can be calculated using this method.

[0080] In a specific embodiment of the present invention, the safety limit of the charging and discharging power of each phase of each inverter is calculated in real time through the impedance matrix, and the original charging and discharging target power of the system is limited by the safety limit of the charging and discharging target power. This can avoid overcurrent problems caused by circulating current, protect the inverter, and ultimately achieve the purpose of protecting the inverter parallel system.

[0081] Another preferred embodiment of the present invention discloses a computer-readable storage medium storing a computer program, wherein the computer program is configured to be run by a processor to perform the steps of the energy dispatching method based on dynamic impedance in the above preferred embodiment.

[0082] Optionally, the aforementioned computer-readable storage media may include, but are not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0083] The background section of this invention may include background information about the problems or circumstances surrounding the invention, rather than a description of prior art by others. Therefore, the content included in the background section is not an admission of prior art by the applicant.

[0084] The background section of this invention may include background information about the problems or circumstances surrounding the invention, rather than a description of prior art by others. Therefore, the content included in the background section is not an admission of prior art by the applicant.

[0085] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate different embodiments or examples and features of different embodiments or examples described in this specification without contradiction. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope defined by the appended claims.

Claims

1. An energy dispatching method based on dynamic impedance, characterized in that, Includes the following steps: S1: Real-time acquisition of the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid; S2: Based on the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid, calculate the safety limit of the charging and discharging power of each phase of each inverter in the parallel system. S3: Adjust the target power allocation based on the calculated safety limit of the charging and discharging power of each phase of each inverter in the parallel system; S2 includes: calculating the maximum value of the ratio of the dynamic impedance of each inverter phase in the parallel system to the sum of the dynamic impedances of all inverter phases in the parallel system based on the dynamic impedance of each inverter corresponding to a certain phase sequence of the power grid; dynamically calculating the safety limit of the charging and discharging power of the inverter phase based on the maximum value of the ratio; and dynamically calculating the safety limit of the charging power of each inverter phase in the parallel system based on the dynamic impedance using formula (1) during charging. In the formula, For the inverter j The total target charging power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters. j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

2. The energy dispatching method based on dynamic impedance according to claim 1, characterized in that, S1 specifically includes: S11: Real-time acquisition of voltage data at the input grid terminal and the grid terminal of each inverter, as well as the effective current value of each inverter; S12: Based on voltage data and effective current values, obtain the dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid in real time.

3. The energy dispatching method based on dynamic impedance according to claim 2, characterized in that, S12 specifically includes: calculating the voltage difference between the voltage data at the input grid terminal and the voltage data at the grid terminal of each inverter based on the voltage data at the input grid terminal and the grid terminal of each inverter, and obtaining the dynamic impedance of each phase sequence of the grid corresponding to each inverter in the parallel system in real time based on the ratio of the voltage difference to the effective value of the current.

4. The energy dispatching method based on dynamic impedance according to claim 1, characterized in that, When formula (1) is used to calculate the inverter's first... j When the total target charging power is less than 0, then the inverter's first... j The total charging target power is set to 0.

5. The energy dispatching method based on dynamic impedance according to claim 1, characterized in that, S2 includes the safety limit of the discharge power of each phase of each inverter in the parallel system, which is dynamically calculated based on the dynamic impedance using formula (2) during the discharge state. In the formula, For the inverter j The total discharge target power, For the inverter j The rated protection power value of the phase, For each inverter j The dynamic impedance of the phase accounts for the largest proportion of all inverters. j The maximum percentage of the sum of the dynamic impedances of the phases. For the inverter j The load power of the off-grid output port of the phase.

6. The energy dispatching method based on dynamic impedance according to claim 1, characterized in that, S1 includes: The dynamic impedance of each inverter in the parallel system corresponding to each phase sequence of the power grid is acquired in real time to generate an n×m dynamic impedance matrix, where n is the number of inverters and m is the number of phases of the inverters; in S2, the dynamic impedance matrix is ​​used to calculate the nth phase of the inverter in the parallel system. i The first inverter j Safety limits for phase charge and discharge power, among which i ≤ n , j ≤ m .

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program is configured to be run by a processor to perform the energy dispatching method based on dynamic impedance as described in any one of claims 1 to 6.

Images