Control and design method of multi-mode access energy storage type power quality treatment device

Abstract

In view to the treatment of voltage quality problem under the influence of power fluctuation of power grid, the application discloses a control and design method of energy storage type power quality treatment device with multi-mode access, and the capacity total of energy storage type power quality treatment device under the same voltage sag compensation requirement is reduced through the complementation of functions of energy storage type power quality treatment devices with two different access modes. For this purpose, firstly, a mathematical model of power grid voltage sag under load side power fluctuation is established, the voltage compensation of series type energy storage and the power compensation of parallel type energy storage are cooperatively controlled, the optimal configuration ratio of energy storage type power quality treatment device is designed according to the power grid and load working condition, and the total amount of energy storage type power quality treatment device to be determined for voltage compensation is obtained according to the analysis of the mathematical model of power grid voltage sag. The method can reduce the overall design capacity of energy storage type power quality treatment device, improve the utilization rate of energy storage unit, and improve the economy of power grid voltage sag compensation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of converters, and relates to the cooperative control of energy storage type power quality treatment devices in series and parallel access modes, in particular to a control and design method of an energy storage type power quality treatment device in multiple modes of access. BACKGROUND

[0002] In a power distribution network, power fluctuation conditions such as impact load and fluctuation of output of new energy equipment can cause voltage sag of the power grid. In order to maintain voltage stability on the user side and ensure power quality of users, an energy storage unit can be used to compensate for voltage sag. The series type energy storage can adjust the voltage of the power grid through a series transformer, and the parallel type energy storage can compensate for the voltage of the power grid by outputting active power and reactive power.

[0003] In a traditional voltage compensation method, compensation for voltage sag mainly adopts a single treatment means of series type energy storage, such as a dynamic voltage restorer and a static synchronous series compensator. In addition, the parallel type energy storage can output or absorb active power and reactive power from the power grid, and therefore research on voltage regulation by using reactive power compensation of the parallel type energy storage is also carried out. Further research has realized voltage regulation without difference under the condition of weak power grid by accessing an energy storage unit through voltage-current droop control.

[0004] In the process of implementing the present application, the inventors have found that the prior art at least has the following problems:

[0005] The traditional voltage compensation method for voltage sag compensation only adopts series type energy storage, has large design capacity, and has single function. When the power grid is in normal operation and the fluctuation power is small, the series type energy storage is in an idle or light load state, and has the disadvantages of low utilization rate and poor economy. SUMMARY

[0006] The purpose of the embodiments of the present application is to provide a control and design method of an energy storage type power quality treatment device in multiple modes of access, which is used to solve the technical problems of single function, low utilization rate and poor economy of the energy storage unit in the related art.

[0007] According to a first aspect of the embodiments of the present application, a design method of an energy storage type power quality treatment device is provided, which is applied to an energy storage type power quality treatment device based on series and parallel access, and includes the following steps.

[0008] A voltage fluctuation mathematical model under fluctuation load power of the power grid is established according to the mathematical interaction relationship between the voltage of the power grid and the power, and a system equivalent impedance Z is derived and solved according to the voltage fluctuation mathematical model. eq ;

[0009] A design method of a controller of series type access energy storage and parallel type access energy storage is determined, and the design method is determined according to a load side power value SL The power factor cosφ and the equivalent impedance Z of the system eq Establish a mathematical model of the voltage compensation capability of energy storage-type power quality management devices;

[0010] Based on the mathematical model of the voltage compensation capability of the energy storage power quality management device system, the evaluation result E of the system's voltage compensation capability under different design schemes to cope with different fluctuating power conditions is generated.

[0011] Analyze and compare the voltage compensation capability evaluation results of the energy storage power quality management device design schemes to determine the optimal configuration ratio σ of series and parallel connected energy storage.

[0012] Based on the optimal configuration ratio σ of the energy storage power quality management device, analyze and calculate the operational weaknesses of voltage sag compensation under the configuration ratio condition.

[0013] Based on the weaknesses in the voltage sag compensation operation of the energy storage-type power quality management device under the optimal configuration ratio, the total system design quantity S is determined. sum ;

[0014] The optimal configuration ratio σ and the total design amount S of the energy storage power quality management device are used. sum As the final design result output.

[0015] Furthermore, based on the mathematical interaction between grid voltage and power, a mathematical model of voltage fluctuation under fluctuating grid load power is established. Based on this voltage fluctuation mathematical model, the system equivalent impedance Z is derived and solved. eq ,include:

[0016] Based on the mathematical interaction between grid voltage and power, a mathematical model of voltage fluctuation under fluctuating grid load power is established;

[0017] By using Thevenin's equivalent theorem, the topology of the energy storage power quality management device connected to the power grid system is simplified into a simplified structure with an ideal voltage source and single-ended output, possessing internal impedance.

[0018] Based on the grid impedance information, load rated power and power factor, and combined with the voltage fluctuation mathematical model, the system equivalent impedance of the simplified structure is derived and calculated.

[0019] Furthermore, in the energy storage power quality management device based on series and parallel access, the design method of the controller for series access energy storage and parallel access energy storage includes voltage compensation for series energy storage, power compensation for parallel energy storage, and coordinated compensation of series and parallel energy storage.

[0020] Furthermore, the voltage compensation of the series-type energy storage includes the following steps:

[0021] Phase-locked loop is applied to the load-side voltage to obtain the load-side electrical angle;

[0022] Based on the load-side electrical angle, an AC voltage at the grid frequency is generated;

[0023] The amplitude of the AC voltage waveform at the grid frequency is normalized based on the rated voltage on the load side to obtain a standard three-phase sinusoidal AC voltage.

[0024] The difference between the actual voltage value on the load side and the standard three-phase sinusoidal AC voltage is used to obtain the voltage to be compensated.

[0025] The effective value of the voltage to be compensated is taken;

[0026] Based on the effective value of the voltage to be compensated, the gain coefficient of the compensation voltage is obtained by proportional-integral control.

[0027] Multiplying the gain coefficient of the compensation voltage by the standard AC voltage on the load side yields the reference voltage output of the series-type energy storage in the three-phase AC coordinate system.

[0028] Furthermore, the parallel-connected energy storage system performs power compensation given active and reactive power command values, comprising the following sub-steps:

[0029] Obtain the power command value of the parallel energy storage system and the current actual output active power and reactive power values;

[0030] Step S42: Calculate the difference between the active power command value and the reactive power command value and the active power and reactive power output by the parallel energy storage, and perform proportional-integral control to obtain the inner loop active current command value and reactive current command value.

[0031] Obtain the actual current output value of the parallel energy storage;

[0032] The actual current output value of the parallel energy storage is subjected to Park transformation to obtain the active current value and reactive current value of the actual output of the parallel energy storage in the synchronous rotating coordinate system.

[0033] The active current command value and reactive current command value are respectively subtracted from the active current value and reactive current value actually output by the parallel energy storage, and proportional-integral control is performed to obtain the reference voltage output of the parallel energy storage in the synchronous rotating coordinate system.

[0034] The reference voltage output of the parallel energy storage in the synchronous rotating coordinate system is subjected to Park inverse transformation to obtain the reference voltage output of the parallel energy storage in the three-phase coordinate system.

[0035] Furthermore, when the output of the series-connected energy storage reaches its capacity limit, the parallel-connected energy storage initiates a coordinated voltage compensation mode. The coordinated compensation of the series and parallel-connected energy storage includes the following sub-steps:

[0036] By detecting the real-time output power of the series-type energy storage, and performing hysteresis control on it according to the capacity value of the series-type energy storage, a logic judgment signal is obtained;

[0037] The logic judgment signal is used as the enable signal for the parallel energy storage collaborative voltage compensation mode;

[0038] Obtain the effective value of the load-side voltage U * loadrms and line current value I line ;

[0039] Under the condition that the enable signal determines that the parallel energy storage is in the cooperative voltage compensation mode, based on the effective value U of the load-side voltage... * loadrms and line current I line The active and reactive power command values ​​of the parallel energy storage are obtained through dynamic coordinated voltage compensation calculation; when the enable signal determines that the parallel energy storage coordinated voltage compensation mode is disabled, the power command value is given by the scheduling command.

[0040] Furthermore, based on the aforementioned mathematical model of voltage compensation capability, an evaluation result E of the system's voltage compensation capability under different design schemes in response to different power fluctuation conditions is generated, including:

[0041] The total design capacity of the energy storage-type power quality management device is set to a constant value, and the single change value of the series-type energy storage capacity is set.

[0042] The series-type energy storage capacity is listed, and the series-type energy storage capacity is gradually increased from zero to the total design amount of the energy storage power quality management device, wherein each change is the single change value of the series-type energy storage capacity;

[0043] Based on the series energy storage capacity design results, the parallel energy storage capacity is the total design capacity of the energy storage power quality management device minus the corresponding series energy storage capacity, resulting in several sets of energy storage power quality management device design schemes with the same total system design capacity but different configuration ratios.

[0044] Using the mathematical model of voltage compensation capability, the voltage compensation capability of each energy storage power quality management device design scheme is calculated to cope with voltage sag problem under the same total power fluctuation and different power factors.

[0045] Based on the voltage compensation capability of the energy storage power quality management device under different conditions, the voltage compensation capability under different power fluctuation conditions under the corresponding design scheme is comprehensively considered, and the evaluation result of the voltage compensation capability of the system under the corresponding design scheme is given.

[0046] Furthermore, based on the optimal configuration ratio σ of the energy storage power quality management device, the operational weaknesses of voltage sag compensation under this configuration ratio condition are analyzed and calculated, including:

[0047] Apply a set of power fluctuation conditions to the system load side;

[0048] In the aforementioned set of power fluctuation conditions, the total amount of fluctuating power is set to the maximum value that may occur under the power grid conditions, and the power factor of the fluctuating power is set to be different for each of them.

[0049] Based on the collaborative voltage compensation method of energy storage power quality management device, the series-connected and parallel-connected energy storage controller design method determined in step S12 is used to compensate for the voltage sag caused by different power factor fluctuation power conditions under the optimal configuration ratio of the energy storage power quality management device. If the energy storage power quality management device can raise the load side voltage to the rated voltage, the compensation level is 1. If the energy storage power quality management device cannot compensate the load side voltage to the rated voltage, the compensation level is (1 - the steady-state voltage deviation value after compensation / the voltage sag depth without voltage compensation).

[0050] Based on the voltage compensation degree of the energy storage power quality management device for voltage sag compensation under the fluctuating power conditions of different power factors, the weak points of the optimal configuration ratio system when performing voltage compensation are analyzed and compared.

[0051] According to a second aspect of the embodiments of this application, a design apparatus for an energy storage power quality management device is provided, applied in an energy storage power quality management device based on series and parallel connection, comprising:

[0052] The derivation module is used to establish a mathematical model of voltage fluctuation under fluctuating load power based on the mathematical interaction between grid voltage and power. Based on this voltage fluctuation mathematical model, the equivalent system impedance Z is derived and solved. eq ;

[0053] The modeling module is used to model the load-side power value S. L The power factor cosφ and the equivalent impedance Z of the system eq Establish a mathematical model of the voltage compensation capability of energy storage-type power quality management devices;

[0054] The generation module is used to generate the voltage compensation capability evaluation result E of the system under different design schemes to cope with different power fluctuation conditions based on the voltage compensation capability mathematical model.

[0055] The analysis module is used to analyze and compare the voltage compensation capability evaluation results E of the design scheme of the energy storage power quality management device, and determine the optimal configuration ratio σ of series and parallel connected energy storage.

[0056] The calculation module is used to analyze and calculate the operational weaknesses of voltage sag compensation under the optimal configuration ratio σ of the energy storage power quality management device.

[0057] The determination module is used to determine the total system design quantity S based on the aforementioned weaknesses. sum ;

[0058] The output module is used to convert the optimal configuration ratio σ and the design total S of the energy storage power quality management device. sum As the final design result output.

[0059] According to a third aspect of the embodiments of this application, an electronic device is provided, comprising:

[0060] One or more processors;

[0061] Memory, used to store one or more programs;

[0062] When the one or more programs are executed by the one or more processors, the one or more processors perform the method as described in the first aspect.

[0063] According to a fourth aspect of the embodiments of this application, a computer-readable storage medium is provided that stores computer instructions thereon, which, when executed by a processor, implement the steps of the method as described in the first aspect.

[0064] The technical solutions provided by the embodiments of this application may include the following beneficial effects:

[0065] As can be seen from the above embodiments, this application improves the energy storage utilization rate and enriches the application functions of energy storage units by coordinating the control of series-connected and parallel-connected energy storage power quality management devices to compensate for voltage sags. Based on the established mathematical model of voltage fluctuation under fluctuating load power and the mathematical model of voltage compensation capability of energy storage power quality management devices, the capacity of energy storage power quality management devices is optimized. Under the condition of meeting the grid voltage sag compensation requirements, the total design capacity of energy storage power quality management devices including series-connected and parallel-connected devices is reduced, thereby improving the system economy.

[0066] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0067] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0068] Figure 1 This is a flowchart illustrating a control and design method for a multi-mode access energy storage power quality management device according to an exemplary embodiment;

[0069] Figure 2 This is a schematic diagram illustrating the basic topology of series and parallel energy storage connected to the power grid according to an exemplary embodiment;

[0070] Figure 3 This is a comparison diagram of the mathematical model of voltage fluctuation under fluctuating load power in the established power grid and the simulation results, based on an exemplary embodiment.

[0071] Figure 4 This is a control block diagram of a series-connected energy storage power quality management device controller according to an exemplary embodiment;

[0072] Figure 5 This is a control block diagram of a parallel-connected energy storage power quality management device controller according to an exemplary embodiment;

[0073] Figure 6 This is a comparison chart of the voltage compensation capability evaluation results of different energy storage power quality management device design schemes in the optimal configuration ratio design according to an exemplary embodiment;

[0074] Figure 7 This is a simulation result diagram showing the degree of load-side voltage compensation under different fluctuating power conditions, based on an exemplary embodiment of the optimal configuration ratio of the energy storage power quality management device.

[0075] Figure 8 This is a block diagram illustrating a control and design device for a multi-mode access energy storage power quality management device according to an exemplary embodiment;

[0076] Figure 9 This is a schematic diagram of an electronic device according to an exemplary embodiment. Detailed Implementation

[0077] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0078] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0079] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0080] Energy storage power quality management devices include energy storage units with two different access methods: series access energy storage power quality management devices (hereinafter referred to as series energy storage) and parallel access energy storage power quality management devices (hereinafter referred to as parallel energy storage).

[0081] The multi-mode access energy storage power quality management device in this application refers to an energy storage power quality management device based on series and parallel access.

[0082] The energy storage power quality management device adopts a collaborative voltage compensation control method. It utilizes the power output characteristics of parallel energy storage and the ability to control the line current flowing through the series transformer on the grid side. When the series energy storage cannot meet the voltage sag compensation requirements on the load side, the parallel energy storage can participate in voltage compensation, further improving the voltage compensation capability of the energy storage power quality management device.

[0083] Figure 1 This is a flowchart illustrating a design method for an energy storage-type power quality management device according to an exemplary embodiment, such as... Figure 1 As shown, this method, applied to energy storage-type power quality management devices based on series and parallel connections, may include the following steps:

[0084] Step S11: Based on the mathematical interaction between grid voltage and power, establish a mathematical model of voltage fluctuation under fluctuating grid load power. Based on the voltage fluctuation mathematical model, derive and solve for the system equivalent impedance Z. eq ;

[0085] Step S12: Determine the design method for series and parallel energy storage controllers, based on the load-side power value S. L Power factor and the equivalent impedance Z of the power grid eq A mathematical model of the voltage compensation capability of the energy storage power quality management device was calculated.

[0086] Step S13: Based on the voltage compensation capability mathematical model, generate the voltage compensation capability evaluation result E of the system under different design schemes to cope with different power fluctuation conditions;

[0087] Step S14: Analyze and compare the voltage compensation capability evaluation results E of the energy storage power quality management device design scheme, and determine the optimal configuration ratio σ of series and parallel connected energy storage.

[0088] Step S15: Based on the optimal configuration ratio σ of the energy storage power quality management device, analyze and calculate the weak points of the system in voltage sag compensation under the configuration ratio condition;

[0089] Step S16: Determine the total system design quantity S based on the aforementioned weaknesses. sum ;

[0090] Step S17: Combine the optimal configuration ratio σ and the design total S of the energy storage power quality management device. sum As the final design result.

[0091] As can be seen from the above embodiments, this application improves the energy storage utilization rate and enriches the application functions of energy storage units by coordinating the control of series-connected and parallel-connected energy storage power quality management devices to compensate for voltage sags. Based on the established mathematical model of voltage fluctuation under fluctuating load power and the mathematical model of voltage compensation capability of energy storage power quality management devices, the configuration ratio and total design amount of the two types of energy storage power quality management devices were designed. Under the condition of meeting the grid voltage sag compensation requirements, the total design amount of capacity of energy storage power quality management devices including series-connected and parallel-connected devices was reduced, thus improving the system economy.

[0092] In the specific implementation of step S11, a mathematical model of voltage fluctuation under fluctuating load power is established based on the mathematical interaction between grid voltage and power. The equivalent system impedance Z is then derived and solved based on this voltage fluctuation mathematical model. eq ;

[0093] Specifically, step S11 includes:

[0094] Step S21: Based on the mathematical interaction between grid voltage and power, establish a mathematical model of voltage fluctuation under fluctuating grid load power;

[0095] Specifically, the influence relationship between load-side fluctuating power and grid voltage fluctuation is obtained through simulation model. The equivalent impedance value of the simplified system is verified and corrected through the mathematical interaction relationship between grid voltage and power. Thus, an analytical model that can replace the simulation model is constructed, namely the mathematical model of voltage fluctuation under grid fluctuating load power. The grid voltage fluctuation value can be calculated through this mathematical model using the corrected equivalent system impedance value and the given load-side fluctuating power value.

[0096] In practical implementation, the analytical results of the impact of grid voltage fluctuations under fluctuating power are obtained through the calculation of the system equivalent impedance, and compared and verified with the simulation results obtained from the simulation model. The comparison results are as follows: Figure 3 As shown, Figure 3 The simulation results ensure the accuracy of the mathematical model of voltage fluctuation under fluctuating load power derived using the system's equivalent impedance.

[0097] Step S22: Using Thevenin's equivalent theorem, the topology of the energy storage power quality management device connected to the power grid system is simplified into a simplified structure with an ideal voltage source single-ended output and internal impedance.

[0098] Specifically, the energy storage power quality management device is connected to the power grid system topology as follows: Figure 2 As shown, the simplified structure obtained after simplification is based on Thevenin's equivalence theorem, which is a well-known technical means in the art, and therefore will not be described in detail here.

[0099] Step S23: Based on the grid impedance information, load rated power and power factor, and combined with the voltage fluctuation mathematical model, derive and calculate the system equivalent impedance of the simplified structure.

[0100] Specifically, the grid-side output impedance is obtained by equivalently connecting the grid-side transmission line impedance to the output impedance of the synchronous machine or thermal power plant constituting the grid-side power supply. Then, the output impedance of the series-type energy storage and parallel-type energy storage access points is equivalently processed to obtain a series impedance connected in series in the grid line and a parallel-type energy storage output impedance connected in parallel. Using Thevenin's equivalent theorem, the grid side of the distribution network, as well as series-type and parallel-type energy storage, are included, simplifying the equivalent structure to a simplified structure of a single-ended output network. The initial value of the system equivalent impedance is obtained according to the impedance series and parallel calculation rule. Then, the system equivalent impedance value is further corrected according to the simulation results of the voltage fluctuation mathematical model so that it can fit the response of the grid side and series-type and parallel-type energy storage to load-side power fluctuations. Finally, the system equivalent impedance of the simplified structure is obtained.

[0101] In practical implementation, the voltage fluctuation mathematical model under the power fluctuation of the power grid can be used to calculate the equivalent impedance of the system by combining the simulation results with the load-side power, power factor and grid-side impedance. Alternatively, the voltage sag depth and the voltage compensation amount of the required energy storage power quality management device can be calculated and determined based on the system equivalent impedance information.

[0102] In the specific implementation of step S12, based on the load-side power value S L Power factor and the system equivalent impedance Z eq A mathematical model of the voltage compensation capability of an energy storage-type power quality management device was established.

[0103] Specifically, the mathematical model for voltage compensation capability mainly considers two aspects. The first aspect is the output power of parallel-connected energy storage, which is combined with the rated power and fluctuating power on the load side to obtain the power transmitted through the power grid. This power is then decomposed into active and reactive power components. Combining this with the resistive and reactive components in the simplified system's equivalent impedance, the voltage impact of energy storage compensation under fluctuating power is calculated using the voltage drop formula. The second aspect is the output compensation voltage of series-connected energy storage. Since series-connected energy storage can be equivalent to a controlled voltage source connected in series with the grid impedance, the series-connected energy storage... The output compensation voltage directly acts on the grid-side voltage and the load-side voltage, directly raising the load-side voltage. The magnitude of this raising effect is influenced by the upper limit of the output compensation voltage of the series-connected energy storage system. This upper limit is limited by the converter capacity; once the converter output power reaches its capacity, the amplitude of the series-connected energy storage output compensation voltage cannot continue to rise. The converter output power is obtained by multiplying voltage and current. The grid line current is calculated by working backward from the load-side power and voltage values. Combined with the design capacity of the series-connected energy storage system, the upper limit of the output compensation voltage can be derived. Considering the combined impact of parallel and series-connected energy storage on the grid load-side voltage under fluctuating power conditions, the voltage compensation capability of the energy storage-type power quality management device is calculated, thus establishing a mathematical model for its voltage compensation capability.

[0104] In the specific implementation of step S12, the controller design method for series energy storage and parallel energy storage in the energy storage power quality management device based on series and parallel access is first determined, including voltage compensation for series energy storage, power compensation for parallel energy storage, and coordinated compensation for series and parallel energy storage.

[0105] The control block diagram of the series-connected energy storage controller is as follows: Figure 4 As shown, the implementation of voltage compensation for the series-type energy storage may include the following steps:

[0106] Step S31: Phase-locked voltage on the load side to obtain the load side electrical angle;

[0107] Step S32: Generate an AC voltage at the grid frequency based on the load-side electrical angle;

[0108] Step S33: Perform amplitude normalization processing on the AC voltage waveform of the power grid frequency based on the rated voltage on the load side to obtain a standard three-phase sinusoidal AC voltage;

[0109] Step S34: Subtract the actual voltage value on the load side from the standard three-phase sinusoidal AC voltage to obtain the voltage to be compensated;

[0110] Step S35: Take the effective value of the voltage to be compensated;

[0111] Step S36: Based on the effective value of the voltage to be compensated, obtain the gain coefficient of the compensation voltage using proportional-integral control;

[0112] Step S37: Multiply the gain coefficient of the compensation voltage by the standard AC voltage on the load side to obtain the reference voltage output of the series-type energy storage in the three-phase AC coordinate system.

[0113] Specifically, the series-side converter control method described in "Zhang Zhenxiao, Zhao Jianyong, Nian Heng, et al. Power grid integrated management and control strategy based on power electronic voltage regulator [J]. Electric Drive, 2022, 52(04):49-55" is adopted to realize the output control of the converter in the form of a controllable voltage source to compensate for the grid voltage.

[0114] The control block diagram of the parallel-connected energy storage controller is as follows: Figure 5 As shown, in step S12, the parallel-connected storage performs power compensation under given active and reactive power command values, including the following sub-steps:

[0115] Step S41: Obtain the parallel energy storage power command value and the current actual output active power value and reactive power value;

[0116] Step S42: Calculate the difference between the active power command value and the reactive power command value and the active power and reactive power output by the parallel energy storage, and perform proportional-integral control to obtain the inner loop active current command value and reactive current command value.

[0117] Step S43: Obtain the actual current output value of the parallel energy storage;

[0118] Step S44: Perform Parker transformation on the actual current output value of the parallel energy storage to obtain the active current value and reactive current value of the actual output of the parallel energy storage in the synchronous rotating coordinate system.

[0119] Step S45: Calculate the difference between the active current command value, the reactive current command value and the actual active current value and reactive current value output by the parallel energy storage, and perform proportional-integral control to obtain the reference voltage output of the parallel energy storage in the synchronous rotating coordinate system.

[0120] Step S46: Perform a Parker inverse transformation on the reference voltage output of the parallel energy storage in the synchronous rotating coordinate system to obtain the reference voltage output of the parallel energy storage in the three-phase coordinate system.

[0121] The control strategy for the parallel-side converter is a dual closed-loop control of the power outer loop and the current inner loop, which is a well-known control method in this field, so it will not be described in detail here.

[0122] When the output of the series-connected energy storage reaches its capacity limit, the parallel-connected energy storage initiates a coordinated voltage compensation mode. The coordinated compensation of the series-connected and parallel-connected energy storage includes the following sub-steps:

[0123] Step S51: By detecting the real-time value of the output power of the series-type energy storage, and performing hysteresis control on it according to the capacity value of the series-type energy storage, a logic judgment signal is obtained;

[0124] Step S52: Use the logic judgment signal as the enable signal for the parallel energy storage cooperative voltage compensation mode;

[0125] Step S53: Obtain the effective value U of the load-side voltage. * loadrms and line current value I line ;

[0126] Step S54: Under the condition that the enable signal determines that the parallel energy storage is in the cooperative voltage compensation mode, based on the effective value U of the load-side voltage... * loadrms and line current I line The active and reactive power command values ​​of the parallel energy storage are obtained through dynamic coordinated voltage compensation calculation; when the enable signal determines that the parallel energy storage coordinated voltage compensation mode is disabled, the power command value is given by the scheduling command.

[0127] Specifically, the voltage compensation requirements for series-connected and parallel-connected energy storage devices are determined based on grid voltage drops and rises. Real-time monitoring of the output capacity of the series-connected energy storage devices is used to determine whether the voltage compensation requirement exceeds the capacity of the series-connected energy storage devices, i.e., the upper limit of the voltage output that the series-connected energy storage devices can compensate. When it is determined that the series-connected energy storage has reached its voltage output limit, the coordinated voltage compensation mode of the parallel-connected energy storage devices is enabled, based on the effective value of the load-side voltage U. * loadrms and line current I line The active and reactive power values ​​to be output by the parallel energy storage are obtained through dynamic coordinated voltage compensation calculation, and the power command of the parallel energy storage device is followed by the power-current dual closed-loop control of the parallel energy storage, so as to realize the coordinated compensation effect of the parallel energy storage on the grid voltage.

[0128] In the specific implementation of step S13, based on the voltage compensation capability mathematical model, an evaluation result E of the system's voltage compensation capability under different design schemes to cope with different fluctuating power conditions is generated;

[0129] Specifically, first, all design schemes for the energy storage-type power quality management devices to be tested are listed, and the voltage compensation capabilities of energy storage-type power quality management devices with different configuration ratios are evaluated one by one. Step S13 includes the following sub-steps:

[0130] Step S61: Set the total design capacity of the energy storage type power quality management device to a constant value, and set the single change value of the series-type energy storage capacity;

[0131] Specifically, the total design capacity of energy storage-type power quality management devices can be set based on the maximum possible fluctuation power value on the load side or the average value of the fluctuation power on the load side obtained from probability and statistics theory analysis. This ensures that the energy storage-type power quality management devices can meet the voltage compensation requirements in most cases under this design capacity. Setting the single change value of the series-type energy storage capacity involves solving and analyzing the optimal configuration ratio of series-type and parallel-type energy storage devices. The smaller the set value, the higher the solution accuracy. It can be adjusted according to the actual situation during use.

[0132] Step S62: List the series-type energy storage capacity, and gradually increase the series-type energy storage capacity from zero to the total design amount of the energy storage power quality management device, wherein each change is the single change value of the series-type energy storage capacity;

[0133] Step S63: Based on the series energy storage capacity design listing results, the parallel energy storage capacity is the total design of the energy storage power quality management device minus the corresponding series energy storage capacity, resulting in several sets of energy storage power quality management device design schemes with the same total system design and different configuration ratios.

[0134] Specifically, through the steps described above, several sets of design schemes for energy storage-type power quality management devices are obtained. Each set of design schemes includes the capacity of series-connected energy storage devices and the capacity of parallel-connected energy storage devices.

[0135] Step S64: Using the voltage compensation capability mathematical model, calculate the voltage compensation capability of each energy storage power quality management device design scheme to cope with voltage sag problems under the same total power fluctuation and different power factors.

[0136] Specifically, in the established mathematical model of voltage compensation capability of energy storage power quality management device, the voltage compensation capability analysis and calculation are performed on the overall design scheme formed by the design capacity of each specific series-type energy storage device and parallel-type energy storage device. The voltage compensation condition given is the same total power fluctuation on the load side, but the power factor of each group of conditions is set differently. In this way, the voltage compensation capability of each group of energy storage power quality management device design scheme to deal with the voltage sag problem under the same total power fluctuation and different power factors can be calculated.

[0137] Step S65: Based on the voltage compensation capability of the energy storage power quality management device under different conditions, comprehensively consider the voltage compensation capability under different power fluctuation conditions under the corresponding design scheme, and give the voltage compensation capability evaluation result E of the system under the corresponding design scheme.

[0138] Specifically, under each group of energy storage power quality management device design schemes, the voltage compensation capability value for voltage sag issues under the same total power fluctuation and different power factors is weighted for each power factor fluctuation power condition. The weighting method can be an average allocation, i.e., allocating weights equally to each condition to form a series of conditions with a total weight of 1, or a specific weight allocation based on the power factor distribution of fluctuating power during actual load operation. Based on the weight allocation results, the voltage compensation capability of each group of energy storage power quality management device design schemes is weighted and calculated to obtain the voltage compensation capability evaluation result for that group of design schemes.

[0139] In one embodiment, steps S61-S65 are specifically implemented as follows: setting the total energy storage amount to 0.1 pu, setting the series-type energy storage capacity value to vary from 0 to 0.1 pu, with a step size b of 0.1 pu × (1 / 100), and setting each individual series-type energy storage capacity value... After obtaining the value, the parallel energy storage capacity is obtained by subtracting the series energy storage capacity value from the total energy storage capacity of 0.1 pu.

[0140]

[0141] The grid line current I is calculated based on the rated load power, fluctuating power, and the parallel energy storage capacity (i.e., the output power of the parallel energy storage) and the actual value of the grid load-side voltage. line .

[0142]

[0143] The actual value of the grid load side voltage Based on fluctuating power and grid-side voltage U g The output power of parallel energy storage and the resistance R of the system's equivalent impedance. eq and reactance X eq Calculated.

[0144]

[0145] U L To consider the impact of load fluctuation power on the grid load-side voltage under the condition that energy storage does not participate in voltage regulation, this study aims to address the issue of load fluctuation power affecting the grid load-side voltage.

[0146]

[0147] Finally, series and parallel energy storage configurations are evaluated, considering power fluctuations. Under the operating condition, the sum of the active and reactive components of the fluctuating power remains at D, while the active component changes from 0 to D, with a step size a of D / 100.

[0148]

[0149] Based on whether the compensated voltage reaches the rated voltage value of the original load side, the evaluation result of the energy storage configuration scheme's voltage compensation capability under this power factor fluctuation situation is obtained. a,b If compensation can be achieved, then E a,b =1, if compensation E cannot be achieved a,b This is to compensate for the ratio of the actual voltage value to the rated value on the load side.

[0150]

[0151] By accumulating the evaluation results E of the energy storage configuration scheme for compensating for fluctuating power conditions with the same power value but different power factors under the same value of b, a,b The evaluation result E of this configuration scheme was obtained. b .

[0152]

[0153] In the specific implementation of step S14, the voltage compensation capability evaluation results of the design scheme of the energy storage power quality management device are analyzed and compared to determine the optimal configuration ratio σ of series and parallel access energy storage.

[0154] Figure 6 The results show the numerical comparison of the comprehensive evaluation results E of 100 energy storage power quality management device design schemes, with the total design capacity of energy storage type power quality management device set at 0.1 pu, the single change value of series energy storage capacity set at 0.01 pu, and the series energy storage capacity gradually increasing from 0 to 0.1 pu.

[0155] Depend on Figure 6 It can be concluded that under the current power grid conditions, the series-type energy storage capacity is 0.043 pu, meaning that the optimal voltage compensation capability is achieved when the ratio of series-type to parallel-type energy storage configuration is 0.43 / 0.57. In other words, under these power grid conditions, the optimal configuration ratio for energy storage-type power quality management devices is 0.43 / 0.57.

[0156] In the specific implementation of step S15, based on the optimal configuration ratio σ of the energy storage power quality management device, the weak points of the system in voltage sag compensation under the configuration ratio condition are analyzed and calculated.

[0157] Specifically, step S15 includes the following sub-steps:

[0158] Step S71: Apply a set of power fluctuation conditions to the system load side;

[0159] Step S72: In the set of power fluctuation conditions, the total amount of fluctuating power is set to the maximum value that may occur under the power grid conditions, and the power factor of the fluctuating power is set to be different for each of them.

[0160] Step S73: Based on the collaborative voltage compensation method of the energy storage power quality management device, the energy storage power quality management device under the optimal configuration ratio compensates for the voltage sag caused by different power factor fluctuation power conditions through the series-connected and parallel-connected energy storage controller design method determined in step S12. If the energy storage power quality management device can raise the load side voltage to the rated voltage, the compensation level is 1. If the energy storage power quality management device cannot compensate the load side voltage to the rated voltage, the compensation level is (1 - the steady-state voltage deviation value after compensation / the voltage sag depth without voltage compensation).

[0161] Step S74: Based on the voltage compensation degree of the energy storage power quality management device in voltage sag compensation under the fluctuating power conditions of different power factors, analyze and compare to find the weak points of the energy storage power quality management device in voltage compensation under the optimal configuration ratio.

[0162] Specifically, under the same total fluctuating power but different power factor fluctuating power conditions, the energy storage design method under test (which includes the total energy storage design and the ratio of series and parallel energy storage) is used to compensate for a series of fluctuating power. Using the voltage compensation capability mathematical model, the voltage compensation level of the energy storage design method for this series of fluctuating power conditions can be calculated in step S73. A voltage compensation level of 1 indicates that the existing energy storage design method can compensate for the fluctuating power conditions with this power factor, restoring the load-side voltage to the rated value. If the voltage compensation level is not 1 and is lower than 1, it indicates that when dealing with the same total fluctuating power, the existing energy storage design method will not be able to compensate the load-side voltage to the rated value for fluctuating power under this power factor condition. The lower the voltage compensation level, the weaker the voltage compensation capability of the existing energy storage design method is when facing fluctuating power under this condition. Therefore, by analyzing the power factor with a low voltage compensation level, the weak point of the energy storage design method in compensating for fluctuating power conditions can be found.

[0163] In the specific implementation of step S16, the total system design quantity S is determined based on the aforementioned weaknesses. sum ;

[0164] Specifically, based on the operational weaknesses of the voltage compensation of the energy storage power quality management device under the optimal configuration ratio, the total design quantity of the energy storage power quality management device is determined, so as to achieve a load-side voltage compensation level of 1 under the operating point condition.

[0165] Figure 7 Simulation results show the degree of load-side voltage compensation for a power quality management device with a total system design capacity of 0.1 pu, designed according to the optimal configuration ratio (0.43 / 0.57) for series and parallel energy storage systems. The device addresses power fluctuations under varying power factor conditions. Figure 7 The voltage compensation level reaches its minimum when the active component of the impact load is 0.16 pu. Therefore, under these grid conditions, the weakest point for the energy storage power quality management device in addressing voltage dips caused by power fluctuations is when the power factor is 0.2. By adjusting the total design capacity of the energy storage power quality management device, the system can compensate the load-side voltage to the rated value under this condition, i.e., the voltage compensation level reaches 1, ultimately resulting in a total design capacity of 0.1212 pu.

[0166] In the specific implementation of step S17, the optimal configuration ratio σ and the design total S of the energy storage power quality management device are combined. sum As the final design result.

[0167] In this embodiment, the configuration ratio of series-type energy storage to parallel-type energy storage is 0.43 / 0.57. Therefore, the final design result output is the optimal configuration ratio σ = 0.43 / 0.57 and the total design quantity S. sum =0.1212 pu. In this energy storage power quality management device, the design capacity of the series-connected energy storage is 0.0521 pu, and the total design capacity of the parallel-connected energy storage is 0.0690 pu. Through the control and design method of the energy storage power quality management device based on series and parallel access, the optimized design quantity of the energy storage power quality management device was obtained, ensuring that the system can cope with the voltage sag problem that may occur in the power grid, while maximizing the utilization rate of the energy storage unit and improving the system economy.

[0168] Corresponding to the aforementioned embodiments of the control and design method for multi-mode access energy storage power quality management devices, this application also provides embodiments of the control and design device for multi-mode access energy storage power quality management devices.

[0169] Figure 8 This is a block diagram illustrating the control and design of a multi-mode access energy storage-type power quality management device according to an exemplary embodiment. (Refer to...) Figure 8 This device, applied in energy storage-type power quality management devices based on series and parallel connection, may include:

[0170] Derivation module 21 is used to establish a mathematical model of voltage fluctuation under fluctuating load power based on the mathematical interaction between grid voltage and power, and to derive and solve the equivalent impedance Z of the system based on the voltage fluctuation mathematical model. eq ;

[0171] Modeling module 22 is used to determine the design methods for series-connected and parallel-connected energy storage controllers, based on the load-side power value S. L Power factor and the system equivalent impedance Z eq Establish a mathematical model of the voltage compensation capability of energy storage-type power quality management devices;

[0172] The generation module 23 is used to generate the voltage compensation capability evaluation result E of the system under different design schemes to cope with different fluctuating power conditions based on the voltage compensation capability mathematical model of the energy storage power quality management device system.

[0173] Analysis module 24 is used to analyze and compare the voltage compensation capability evaluation results of the design scheme of the energy storage power quality management device, and determine the optimal configuration ratio σ of series and parallel connected energy storage.

[0174] The calculation module 25 is used to analyze and calculate the operational weaknesses of voltage sag compensation under the optimal configuration ratio σ of the energy storage power quality management device.

[0175] Module 26 is used to determine the total system design quantity S based on the weak points in the operation of the voltage sag compensation of the energy storage power quality management device under the optimal configuration ratio. sum ;

[0176] Output module 27 is used to output the optimal configuration ratio σ and the design total S of the energy storage power quality management device. sum As the final design result output.

[0177] Specifically, in the derivation module 21, a mathematical model of voltage fluctuation under fluctuating load power is established based on the mathematical interaction between grid voltage and power; the topology of the energy storage power quality management device connected to the grid is simplified into a simplified structure with an ideal voltage source single-ended output and internal impedance by using Thevenin's equivalent theorem; based on grid impedance information, rated load power and power factor, combined with the voltage fluctuation mathematical model, the system equivalent impedance of the simplified structure is derived and calculated.

[0178] Specifically, in energy storage-type power quality management devices based on series and parallel access, the design methods for series and parallel access energy storage controllers include voltage compensation for series energy storage, power compensation for parallel energy storage, and coordinated compensation for series and parallel energy storage.

[0179] The voltage compensation for the series-type energy storage is achieved by including:

[0180] Phase-locked loop (PLL) is applied to the load-side voltage to obtain the load-side electrical angle. Based on the load-side electrical angle, an AC voltage at the grid frequency is generated. The amplitude of the AC voltage waveform at the grid frequency is standardized according to the load-side rated voltage to obtain a standard three-phase sinusoidal AC voltage. The difference between the actual load-side voltage and the standard three-phase sinusoidal AC voltage is calculated to obtain the voltage to be compensated. The effective value of the voltage to be compensated is taken. Based on the effective value of the voltage to be compensated, proportional-integral control (PIC) is used to obtain the gain coefficient of the compensation voltage. The gain coefficient of the compensation voltage is multiplied by the standard AC voltage on the load side to obtain the reference voltage output of the series-type energy storage in the three-phase AC coordinate system.

[0181] Among them, the parallel-connected energy storage system performs power compensation under given active and reactive power command values, including:

[0182] The following steps are performed: 1. Obtain the power command value of the parallel energy storage system and the current actual output active and reactive power values. 2. Subtract the active and reactive power command values ​​from the actual output active and reactive power of the parallel energy storage system, and perform proportional-integral control to obtain the inner-loop active current command value and reactive current command value. 3. Obtain the actual current output value of the parallel energy storage system. 4. Perform a Parker transformation on the actual current output value of the parallel energy storage system to obtain the actual output active and reactive current values ​​of the parallel energy storage system in a synchronous rotating coordinate system. 5. Subtract the active and reactive current command values ​​from the actual output active and reactive current values ​​of the parallel energy storage system, and perform proportional-integral control to obtain the reference voltage output of the parallel energy storage system in a synchronous rotating coordinate system. 6. Perform an inverse Parker transformation on the reference voltage output of the parallel energy storage system in a synchronous rotating coordinate system to obtain the reference voltage output of the parallel energy storage system in a three-phase coordinate system.

[0183] When the output of the series-connected energy storage reaches its capacity limit, the parallel-connected energy storage initiates a coordinated voltage compensation mode. The coordinated compensation of the series-connected and parallel-connected energy storage includes the following sub-steps:

[0184] By detecting the real-time output power of the series-type energy storage, hysteresis control is performed on it according to the capacity value of the series-type energy storage to obtain a logic judgment signal; the logic judgment signal is used as the enable signal for the parallel-type energy storage cooperative voltage compensation mode; and the effective value of the load-side voltage U is obtained. * loadrmsand line current value I line Under the condition that the enable signal determines that the parallel energy storage is in the cooperative voltage compensation mode, based on the effective value U of the load-side voltage... * loadrms and line current I line The active and reactive power command values ​​of the parallel energy storage are obtained through dynamic coordinated voltage compensation calculation; when the enable signal determines that the parallel energy storage coordinated voltage compensation mode is disabled, the power command value is given by the scheduling command.

[0185] Specifically, in the generation module 23, the total design capacity of the energy storage power quality management device is set to a constant value, and the single change value of the series energy storage capacity is set. The series energy storage capacity is enumerated, and the series energy storage capacity is gradually increased from zero to the total design capacity of the energy storage power quality management device, wherein each change is the single change value of the series energy storage capacity. According to the enumeration result of the series energy storage capacity design, the parallel energy storage capacity is the total design capacity of the energy storage power quality management device minus the corresponding series energy storage capacity, resulting in several sets of energy storage power quality management device design schemes with the same total system design capacity but different configuration ratios. Through the voltage compensation capability mathematical model, the voltage compensation capability of each set of energy storage power quality management device design schemes is calculated to cope with the voltage sag problem under the same total power fluctuation and different power factors. Based on the voltage compensation capability of the energy storage power quality management device under different conditions, the voltage compensation capability under different power fluctuation conditions under the corresponding design scheme is comprehensively considered, and the voltage compensation capability evaluation result of the system under the corresponding design scheme is given.

[0186] Specifically, in the calculation module 25, a set of power fluctuation conditions is applied to the system load side. In this set of power fluctuation conditions, the total amount of fluctuating power is set to the maximum value that may occur under the grid conditions, and the power factors of the fluctuating power are set to be different for each of them. Based on the collaborative voltage compensation method of the energy storage power quality management device, the series-connected energy storage and parallel-connected energy storage controller design method determined in step S12 is used to compensate the voltage sag caused by the power fluctuation conditions of different power factors under the optimal configuration ratio of the energy storage power quality management device. If the energy storage power quality management device can raise the load side voltage to the rated voltage, the compensation level is 1. If the energy storage power quality management device cannot compensate the load side voltage to the rated voltage, the compensation level is (1 - the steady-state voltage deviation value after compensation / the voltage sag depth without voltage compensation). According to the voltage compensation level of the energy storage power quality management device for voltage sag compensation under the power fluctuation conditions of different power factors, the working weakness of the optimal configuration ratio system when performing voltage compensation is analyzed and compared.

[0187] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0188] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0189] Accordingly, this application also provides an electronic device, including: one or more processors; a memory for storing one or more programs; and when the one or more programs are executed by the one or more processors, causing the one or more processors to implement the control and design method for the multi-mode access energy storage type power quality management device as described above. Figure 9 The diagram shown is a hardware structure diagram of any data processing-capable device where a deep learning dataset access system is located, according to an embodiment of the present invention. Except for... Figure 9 In addition to the processor, memory, and network interface shown, any data processing device in the embodiment may also include other hardware depending on the actual function of the data processing device, which will not be described in detail here.

[0190] Accordingly, this application also provides a computer-readable storage medium storing computer instructions, which, when executed by a processor, implement the control and design method for a multi-mode access energy storage-type power quality management device as described above. The computer-readable storage medium can be an internal storage unit of any data processing-capable device as described in any of the foregoing embodiments, such as a hard disk or memory. The computer-readable storage medium can also be an external storage device for a wind turbine, such as a plug-in hard disk, smart media card (SMC), SD card, flash card, etc., equipped on the device. Furthermore, the computer-readable storage medium can include both internal storage units of any data processing-capable device and external storage devices. The computer-readable storage medium is used to store the computer program and other programs and data required by the data processing-capable device, and can also be used to temporarily store data that has been output or will be output.

[0191] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0192] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A design method for an energy storage-type power quality management device, applied to energy storage-type power quality management devices based on series and parallel connection, characterized in that, include: Based on the mathematical interaction between grid voltage and power, a mathematical model of voltage fluctuation under fluctuating load power is established. Based on this voltage fluctuation mathematical model, the system equivalent impedance is derived and solved. Z eq ; Based on the load-side power value S L Power factor cos φ and the system equivalent impedance Z eq Establish a mathematical model of the voltage compensation capability of energy storage-type power quality management devices; Based on the mathematical model of voltage compensation capability, evaluation results of the system's voltage compensation capability under different design schemes and different power fluctuation conditions are generated. E ; The voltage compensation capability evaluation results of the proposed energy storage-type power quality management device design schemes were analyzed and compared. E Determine the optimal configuration ratio of series and parallel connected energy storage. σ ; Based on the optimal configuration ratio of the energy storage-type power quality management device σ The analysis and calculation of the operational weaknesses of voltage sag compensation under this configuration ratio condition were performed. Based on the aforementioned weaknesses, determine the total system design quantity. S sum To achieve a load-side voltage compensation level of 1 under the operating point condition; The optimal configuration ratio of the energy storage power quality management device σ and total design volume S sum As the final design result; Among them, according to the optimal configuration ratio of the energy storage type power quality management device σ The analysis and calculation of the operational weaknesses of voltage sag compensation under this configuration ratio condition include: Apply a set of power fluctuation conditions to the system load side; In the aforementioned set of power fluctuation conditions, the total amount of fluctuating power is set to the maximum value that may occur under the power grid conditions, and the power factor of the fluctuating power is set to be different for each of them. Based on the collaborative voltage compensation method of energy storage power quality management device, the series-connected and parallel-connected energy storage controller design method determined in step S12 is used to compensate for the voltage sag caused by different power factor fluctuation power conditions under the optimal configuration ratio of the energy storage power quality management device. If the energy storage power quality management device can raise the load side voltage to the rated voltage, the compensation level is 1. If the energy storage power quality management device cannot compensate the load side voltage to the rated voltage, the compensation level is (1 - the steady-state voltage deviation value after compensation / the voltage sag depth without voltage compensation). Based on the voltage compensation degree of the energy storage power quality management device for voltage sag compensation under the fluctuating power conditions of different power factors, the weak points of the optimal configuration ratio system when performing voltage compensation are analyzed and compared.

2. The method according to claim 1, characterized in that, Based on the mathematical interaction between grid voltage and power, a mathematical model of voltage fluctuation under fluctuating load power is established. Based on this voltage fluctuation mathematical model, the system equivalent impedance is derived and solved. Z eq ,include: Based on the mathematical interaction between grid voltage and power, a mathematical model of voltage fluctuation under fluctuating grid load power is established; By using Thevenin's equivalent theorem, the topology of the energy storage power quality management device connected to the power grid system is simplified into a simplified structure with an ideal voltage source and single-ended output, possessing internal impedance. Based on the grid impedance information, load rated power and power factor, and combined with the voltage fluctuation mathematical model, the system equivalent impedance of the simplified structure is derived and calculated.

3. The method according to claim 1, characterized in that, In the energy storage power quality management device based on series and parallel access, the design method of the energy storage controller for series and parallel access includes voltage compensation for series energy storage, power compensation for parallel energy storage, and coordinated compensation of series and parallel energy storage.

4. The method according to claim 3, characterized in that, The voltage compensation of the series-type energy storage includes the following steps: Phase-locked loop is applied to the load-side voltage to obtain the load-side electrical angle; Based on the load-side electrical angle, an AC voltage at the grid frequency is generated; The amplitude of the AC voltage waveform at the grid frequency is normalized based on the rated voltage on the load side to obtain a standard three-phase sinusoidal AC voltage. The difference between the actual voltage value on the load side and the standard three-phase sinusoidal AC voltage is used to obtain the voltage to be compensated. The effective value of the voltage to be compensated is taken; Based on the effective value of the voltage to be compensated, the gain coefficient of the compensation voltage is obtained by proportional-integral control. Multiplying the gain coefficient of the compensation voltage by the standard AC voltage on the load side yields the reference voltage output of the series-type energy storage in the three-phase AC coordinate system.

5. The method according to claim 3, characterized in that, Parallel-connected energy storage performs power compensation given active and reactive power command values, including the following sub-steps: Take the parallel energy storage power command value and the current actual output active power value and reactive power value; The active power command value and reactive power command value are respectively subtracted from the active power and reactive power output of the parallel energy storage, and proportional-integral control is performed to obtain the inner loop active current command value and reactive current command value. Obtain the actual current output value of the parallel energy storage; The actual current output value of the parallel energy storage is subjected to Park transformation to obtain the active current value and reactive current value of the actual output of the parallel energy storage in the synchronous rotating coordinate system. The active current command value and reactive current command value are respectively subtracted from the active current value and reactive current value actually output by the parallel energy storage, and proportional-integral control is performed to obtain the reference voltage output of the parallel energy storage in the synchronous rotating coordinate system. The reference voltage output of the parallel energy storage in the synchronous rotating coordinate system is subjected to Park inverse transformation to obtain the reference voltage output of the parallel energy storage in the three-phase coordinate system.

6. The method according to claim 3, characterized in that, When the output of series-connected energy storage reaches its capacity limit, parallel-connected energy storage initiates a coordinated voltage compensation mode. The coordinated compensation of series and parallel-connected energy storage includes the following sub-steps: By detecting the real-time output power of the series-type energy storage, and performing hysteresis control on it according to the capacity value of the series-type energy storage, a logic judgment signal is obtained; The logic judgment signal is used as the enable signal for the parallel energy storage collaborative voltage compensation mode; Obtain the effective value of the load-side voltage U * loadrms and line current value I line ; Under the condition that the enable signal determines that the parallel energy storage is in cooperative voltage compensation mode, based on the effective value of the load-side voltage... U * loadrms and line current I line The active and reactive power command values ​​of the parallel energy storage are obtained through dynamic coordinated voltage compensation calculation; when the enable signal determines that the parallel energy storage coordinated voltage compensation mode is disabled, the power command value is given by the scheduling command.

7. The method according to claim 1, characterized in that, Based on the mathematical model of voltage compensation capability, evaluation results of the system's voltage compensation capability under different design schemes and different power fluctuation conditions are generated. E ,include: The total design capacity of the energy storage-type power quality management device is set to a constant value, and the single change value of the series-type energy storage capacity is set. The series-type energy storage capacity is listed, and the series-type energy storage capacity is gradually increased from zero to the total design amount of the energy storage power quality management device, wherein each change is the single change value of the series-type energy storage capacity; Based on the series energy storage capacity design results, the parallel energy storage capacity is the total design capacity of the energy storage power quality management device minus the corresponding series energy storage capacity, resulting in several sets of energy storage power quality management device design schemes with the same total system design capacity but different configuration ratios. Using the mathematical model of voltage compensation capability, the voltage compensation capability of each energy storage power quality management device design scheme is calculated to cope with voltage sag problem under the same total power fluctuation and different power factors. Based on the voltage compensation capability of the energy storage power quality management device under different conditions, the voltage compensation capability under different power fluctuation conditions under the corresponding design scheme is comprehensively considered, and the evaluation result of the voltage compensation capability of the system under the corresponding design scheme is given.

8. A design device for an energy storage-type power quality management device, applied in energy storage-type power quality management devices based on series and parallel connection, characterized in that, include: The derivation module is used to establish a mathematical model of voltage fluctuation under fluctuating load power based on the mathematical interaction between grid voltage and power, and to derive and solve the equivalent impedance of the system based on the voltage fluctuation mathematical model. Z eq ; The modeling module is used to model the load-side power values. S L Power factor cos φ and the system equivalent impedance Z eq Establish a mathematical model of the voltage compensation capability of energy storage-type power quality management devices; The generation module is used to generate evaluation results of the system's voltage compensation capability under different design schemes and different power fluctuation conditions based on the voltage compensation capability mathematical model. E ; The analysis module is used to analyze and compare the voltage compensation capability evaluation results of the energy storage-type power quality management device design scheme. E Determine the optimal configuration ratio of series and parallel connected energy storage. σ ; The calculation module is used to calculate the optimal configuration ratio of the energy storage power quality management device. σ The analysis and calculation of the operational weaknesses of voltage sag compensation under this configuration ratio condition were performed. The determination module is used to determine the total system design quantity based on the aforementioned weaknesses. S sum To achieve a load-side voltage compensation level of 1 under the operating point condition; The output module is used to output the optimal configuration ratio of the energy storage power quality management device. σ and total design volume S sum As the final design result output; Among them, according to the optimal configuration ratio of the energy storage type power quality management device σ The analysis and calculation of the operational weaknesses of voltage sag compensation under this configuration ratio condition include: Apply a set of power fluctuation conditions to the system load side; In the aforementioned set of power fluctuation conditions, the total amount of fluctuating power is set to the maximum value that may occur under the power grid conditions, and the power factor of the fluctuating power is set to be different for each of them. Based on the collaborative voltage compensation method of energy storage power quality management device, the series-connected and parallel-connected energy storage controller design method determined in step S12 is used to compensate for the voltage sag caused by different power factor fluctuation power conditions under the optimal configuration ratio of the energy storage power quality management device. If the energy storage power quality management device can raise the load side voltage to the rated voltage, the compensation level is 1. If the energy storage power quality management device cannot compensate the load side voltage to the rated voltage, the compensation level is (1 - the steady-state voltage deviation value after compensation / the voltage sag depth without voltage compensation). Based on the voltage compensation degree of the energy storage power quality management device for voltage sag compensation under the fluctuating power conditions of different power factors, the weak points of the optimal configuration ratio system when performing voltage compensation are analyzed and compared.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method as described in any one of claims 1-7.

Images