A multi-dc / dc source energy storage converter adaptive regulation method and system
Patent Information
- Application Number
- CN202611086084.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-21
- Publication Date
- 2026-10-30
AI Technical Summary
[0004]针对现有技术存在的上述缺陷，本申请提供一种多DC/DC源储能变换器自适应调控方法及系统，旨在解决现有多DC/DC源储能变换器控制方法存在的各支路储能功率振荡严重、储能功率支撑能力差与实时控制精度不足的问题
1、通过对直流母线电容能量偏差、电压偏差与电压变化率，获取可准确对直流母线能量过剩或缺额状态进行判别的目标能量风险指标；通过直流侧功率失衡量、各储能设备的储能执行功率、直流母线电容能量偏差、电压偏差与电压变化率之间的功率平衡关系，可准确获取需要对各储能支路进行充电或放电时总储能支撑功率，进而通过各储能支路的支路运行系数、储能执行功率与支路荷电量，获取各储能支路储能分配系数与对应的目标储能执行功率，可在保证各配电设备充放电安全的同时，避免总储能支撑功率分配失衡与支路瞬时功率冲击过大，从而可在此基础上准确快速地调控各储能支路的DC/DC变换器占空比，提高配电网的母线电压恢复速度与整体储能功率支撑能力。
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Abstract
Description
Technical Field
[0001] This application belongs to the field of energy storage control technology for power distribution networks, and more specifically, relates to an adaptive control method and system for multi-DC / DC source energy storage converters. Background Technology
[0002] With the continuous integration of distributed photovoltaic (PV) systems, energy storage systems, and grid-connected converters into distribution networks, DC-type or AC / DC hybrid microgrids are gradually becoming an important form of local consumption of new energy and flexible power regulation. In systems with multiple energy storage devices connected in parallel, each energy storage device is typically connected to a common DC bus through an independent bidirectional DC / DC energy storage converter. Since the SOC, rated capacity, internal resistance, temperature, converter current limiting state, and power margin of each energy storage device are not consistent, if a fixed ratio allocation or uniform droop control is still used for each bidirectional DC / DC energy storage converter branch of the DC bus, problems such as unreasonable power sharing, imbalance of SOC (State of Charge) charging and discharging power distribution, and branch power overshoot may occur in each branch. Therefore, a large number of control methods for multi-DC / DC source energy storage converters on the DC bus have emerged.
[0003] Existing control methods for multi-DC / DC source energy storage converters mainly consist of independent voltage control, fixed droop control, and centralized optimized allocation. Independent voltage control relies on the local response of each DC / DC branch to DC bus voltage deviations, lacking collaborative analysis of the SOC of energy storage devices in each branch. This may lead to significant energy storage power oscillations and sharing deviations in each DC / DC branch (energy storage converter branch). Fixed droop control can improve power distribution, but the droop coefficient usually does not change with the SOC, power margin, and current limiting status of each DC / DC branch. When there is an energy shortage or surplus on the common DC bus, it is difficult to provide real-time and accurate dynamic energy storage power support for each branch (overcharging and discharging the branch SOC). Centralized optimized allocation can comprehensively consider multiple grid constraints, but it usually has a long calculation cycle and is highly dependent on the communication integrity of each branch and the modeling accuracy of the global distribution network model. It is difficult to directly adapt to millisecond to second-level disturbances on the DC bus, thus severely reducing real-time control accuracy. Summary of the Invention
[0004] To address the aforementioned deficiencies in existing technologies, this application provides an adaptive control method and system for multi-DC / DC source energy storage converters, aiming to solve the problems of severe oscillation of energy storage power in each branch, poor energy storage power support capability, and insufficient real-time control accuracy in existing multi-DC / DC source energy storage converter control methods.
[0005] In a first aspect, this application provides an adaptive control method for a multi-DC / DC source energy storage converter, including: S1. Obtain the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period. The DC bus status parameters include DC bus voltage, DC bus capacitance, AC side active power transmitted to the grid-connected inverter, DC side load power, and photovoltaic input power input by the photovoltaic branch. The branch status parameters include branch operating coefficient, energy storage execution power of the energy storage device connected to the DC bus, branch inductor current, and branch charge. S2. Based on photovoltaic input power, AC side active power, DC side load power, DC bus voltage and DC bus capacitance, obtain the DC side power loss of the DC bus, DC bus capacitance energy deviation, voltage deviation and voltage change rate, and target energy risk indicators. S3. When the target energy risk index deviates from the preset safety threshold range, the total energy storage support power is obtained based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, voltage deviation and voltage change rate. S4. Based on the branch operation coefficient, energy storage execution power and branch charge of each energy storage branch, obtain the energy storage allocation coefficient corresponding to each energy storage branch, and adjust the duty cycle of the DC / DC converter of each energy storage branch based on each energy storage allocation coefficient and the total energy storage support power.
[0006] Further, step S2 includes: S21. Based on the DC bus voltage, DC bus capacitance, DC bus rated voltage and rated capacitor energy during the current sampling period, and the DC bus voltage during the previous sampling period, obtain the DC bus capacitor energy deviation, voltage deviation and voltage change rate, and obtain the target energy risk index based on the DC bus capacitor energy deviation, voltage deviation and voltage change rate. S22. Based on the power balance relationship between photovoltaic input power, AC side active power, DC side load power, DC bus voltage, DC bus capacitance and the execution power of each energy storage, obtain the DC side power loss of the DC bus.
[0007] Furthermore, the calculation formula for obtaining the standard energy risk index is as follows:
[0008] in, Sampling period The target energy risk indicator, The rated DC bus voltage, Sampling period DC bus voltage, Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, This refers to the rated capacitor energy of the DC bus. , and These are the risk weights corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively. The maximum rated rate of change of DC bus voltage is allowed. The time difference between two adjacent sampling periods.
[0009] Furthermore, the formula for obtaining the total energy storage support power is expressed as follows:
[0010] in, Sampling period Total energy storage capacity and These are the maximum discharge power and maximum charging power corresponding to the sum of the energy storage execution power of the energy storage devices, respectively. It is a saturation limiting function. Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, Sampling period DC-side power loss measurement , and These are the control gains corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively.
[0011] Furthermore, the energy storage allocation coefficients corresponding to each energy storage branch are obtained, including: S41. Based on the branch operation coefficient, energy storage execution power, branch charge, maximum charge upper limit, minimum charge lower limit and rated maximum energy storage execution power of each energy storage branch during the current sampling period, obtain the energy storage allocation coefficient of each energy storage branch. S42. Based on the total energy storage support power and the energy storage allocation coefficient of each energy storage branch, obtain the target energy storage execution power of each energy storage branch, and adjust the duty cycle of the DC / DC converter of each energy storage branch based on the target energy storage execution power.
[0012] Furthermore, the branch operation coefficients include measurement quality coefficient, communication reliability coefficient, current limiting state coefficient, and temperature safety coefficient.
[0013] Furthermore, based on the target energy storage execution power, the duty cycle of the DC / DC converter in each energy storage branch is adjusted, including: Based on the rated power change rate range of the energy storage branch during the current sampling period, the power change rate during the process of adjusting the energy storage execution power to the target energy storage execution power is constrained until the energy storage execution power of the energy storage branch is adjusted to the target energy storage execution power. Based on the DC bus voltage and target energy storage power during the current sampling period, the target branch inductor current of the energy storage branch is obtained, and the duty cycle of the DC / DC converter of the energy storage branch is adjusted based on the deviation between the target branch inductor current and the branch inductor current.
[0014] Furthermore, prior to step S4, the following steps are also included: Based on the DC bus capacitor energy deviation, voltage deviation, and AC side active power of the grid-connected inverter, the target AC side active power is obtained. Based on the deviation between the target AC side active power and the AC side active power, the AC side active power is adjusted under the constraint of the power change rate range of the grid-connected inverter.
[0015] The existing control of DC / DC converters for each energy storage branch relies solely on DC bus voltage deviation to adjust the execution power of the energy storage device, which has a series of progressive defects: 1. The energy of the bus capacitor and the bus voltage have a quadratic nonlinear relationship. The voltage deviation alone cannot accurately represent the actual energy surplus or deficit of the bus, and therefore cannot adjust the energy storage execution power of each energy storage branch according to the actual charging and discharging requirements, thus failing to achieve adaptive adjustment of each DC / DC converter; 2. Relying on DC bus voltage deviation cannot effectively adjust the active power on the AC side of the grid-connected inverter. All power disturbances experienced by the DC bus of the distribution network during energy storage support can only be shared by the energy storage branch, which increases the risk of instantaneous power surges in the energy storage execution power.
[0016] Secondly, this application also provides an adaptive control system for a multi-DC / DC source energy storage converter, used to perform any of the methods described above, including: The status parameter acquisition module is used to acquire the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period. The energy risk indicator acquisition module is used to acquire the DC-side power loss of the DC bus, the DC bus capacitor energy deviation, the voltage deviation and voltage change rate, and the target energy risk indicator based on the photovoltaic input power, AC-side active power, DC-side load power, DC bus voltage and DC bus capacitance. The energy storage support power acquisition module is used to acquire the total energy storage support power based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, voltage deviation and voltage change rate when the target energy risk index deviates from the preset safety threshold range. The energy storage allocation coefficient acquisition module is used to obtain the energy storage allocation coefficient corresponding to each energy storage branch based on the branch operation coefficient, energy storage execution power and branch load of each energy storage branch. The DC / DC converter adjustment module is used to adjust the duty cycle of the DC / DC converters of each energy storage branch based on the energy storage allocation coefficient and the total energy storage support power.
[0017] Thirdly, this application also provides an electronic device, characterized in that it comprises: At least one memory for storing computer programs; At least one processor is configured to execute a program stored in the memory, such that, when the program is executed, the processor performs the method described in the first aspect or any possible implementation thereof.
[0018] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: 1. By analyzing the DC bus capacitor energy deviation, voltage deviation, and voltage change rate, target energy risk indicators can be obtained to accurately determine the excess or deficiency state of DC bus energy. By analyzing the power balance relationship between DC-side power loss, the energy storage execution power of each energy storage device, DC bus capacitor energy deviation, voltage deviation, and voltage change rate, the total energy storage support power when charging or discharging each energy storage branch can be accurately obtained. Furthermore, by analyzing the branch operation coefficient, energy storage execution power, and branch charge of each energy storage branch, the energy storage allocation coefficient and corresponding target energy storage execution power of each energy storage branch can be obtained. This ensures the charging and discharging safety of each power distribution device while avoiding imbalance in the total energy storage support power distribution and excessive instantaneous power surges in the branches. Based on this, the duty cycle of the DC / DC converters of each energy storage branch can be accurately and quickly adjusted to improve the bus voltage recovery speed and overall energy storage power support capability of the distribution network.
[0019] 2. By measuring the DC bus capacitor energy deviation, voltage deviation, and AC side active power of the grid-connected inverter, the target AC side active power can be obtained. Based on the target AC side active power, the grid-connected inverter can be power-regulated. This allows all power disturbances experienced by the DC bus during energy storage support to be shared by each energy storage branch, reducing power oscillations in each energy storage branch. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in this application or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a flowchart illustrating the adaptive control method for multi-DC / DC source energy storage converters provided in the embodiments of this application.
[0022] Figure 2 A schematic diagram of the power distribution network structure corresponding to the multi-DC / DC source energy storage converter provided in the embodiments of this application.
[0023] Figure 3 This is another flowchart illustrating the adaptive control method for multi-DC / DC source energy storage converters provided in the embodiments of this application.
[0024] Figure 4 A comparison curve of the AC side active power of the grid-connected inverter provided in the embodiments of this application before and after correction.
[0025] Figure 5 A comparison curve of the total energy storage power before and after correction of the grid-connected inverter provided in the embodiments of this application.
[0026] Figure 6 A comparison curve of the DC bus voltage before and after correction for the grid-connected inverter provided in the embodiments of this application.
[0027] Figure 7 This is a schematic diagram of the structure of the adaptive control system for a multi-DC / DC source energy storage converter provided in an embodiment of this application.
[0028] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0029] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.
[0030] In the following description, the terms "second" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The following description provides multiple embodiments of this application, which can be substituted or combined with each other. Therefore, this application can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more other possible combinations of A, B, C, and D, even if such embodiments are not explicitly described in the following text.
[0031] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of this application. Various processes or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.
[0032] Figure 1 This is a flowchart illustrating the adaptive control method for multi-DC / DC source energy storage converters provided in this application embodiment. The method includes the following steps: S1. Obtain the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period.
[0033] In the embodiments of this application, such as Figure 2 The implementing entity of the method shown in this application can be a collaborative controller of a distribution network system composed of a common DC bus, multiple energy storage branches, photovoltaic branches, and a grid-connected inverter. The photovoltaic branches consist of a DC / DC converter and photovoltaic equipment, while the energy storage branches consist of a bidirectional DC / DC converter and energy storage equipment, which can be used for charging and discharging interaction with the DC bus. The grid-connected inverter is sequentially connected to the AC filter interface and the external AC grid PCC. This application does not limit the specific topology of the bidirectional DC / DC converter; it can be a bidirectional Buck Boost converter, an interleaved parallel bidirectional converter, an isolated bidirectional converter, or other power electronic converters capable of realizing energy storage charging and discharging control. The grid-connected inverter can employ voltage-oriented control, power outer loop current inner loop control, or other control structures suitable for grid-connected microgrids. The DC bus status parameters include DC bus voltage, DC bus capacitance, AC side active power transmitted to the grid-connected inverter, DC side load power, and photovoltaic input power input from the photovoltaic branch. The branch status parameters include branch operating coefficient, energy storage execution power of the energy storage device connected to the DC bus, branch inductor current, and branch charge. The formula symbols for the electrical quantities in this application can be found in the following formulas.
[0034] S2. Based on photovoltaic input power, AC side active power, DC side load power, DC bus voltage and DC bus capacitance, obtain the DC side power loss of the DC bus, DC bus capacitance energy deviation, voltage deviation and voltage change rate, and target energy risk indicators.
[0035] In one possible implementation, step S2 includes: S21. Based on the DC bus voltage, DC bus capacitance, DC bus rated voltage and rated capacitor energy during the current sampling period, and the DC bus voltage during the previous sampling period, obtain the DC bus capacitor energy deviation, voltage deviation and voltage change rate, and obtain the target energy risk index based on the DC bus capacitor energy deviation, voltage deviation and voltage change rate. S22. Based on the power balance relationship between photovoltaic input power, AC side active power, DC side load power, DC bus voltage, DC bus capacitance and the execution power of each energy storage, obtain the DC side power loss of the DC bus.
[0036] In this embodiment, the expressions for DC bus capacitor energy and energy deviation are:
[0037] in, For DC bus capacitors, Sampling period The DC bus voltage has a very short time difference between adjacent sampling periods, which can be equivalent to a single sampling time point. Sampling period DC bus capacitor energy, Rated capacitor energy, This refers to the DC bus capacitor energy deviation. Generally, when... When the DC bus capacitor energy is lower than the rated capacitor energy, the distribution network system has an energy deficit. At that time, there is excess energy in the distribution network system. However, since the actual energy risk of the DC bus is affected by voltage deviation and instantaneous voltage fluctuation (voltage change rate), judging whether the DC bus needs charging and discharging solely based on the DC bus capacitor energy will result in significant deviation. Therefore, this application proposes a target energy risk index, expressed by the following formula:
[0038] in, Sampling period The target energy risk indicator, The rated DC bus voltage, Sampling period DC bus voltage, Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, This refers to the rated capacitor energy of the DC bus. , and These are the risk weights corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively. The maximum rated rate of change of DC bus voltage is allowed. The time difference between two adjacent sampling periods.
[0039] like Figure 3 As shown, in order to accurately obtain the total energy storage support power (total discharge power or total charging power) of each energy storage branch, it is necessary to obtain the DC side power loss of the DC bus, and the formula for obtaining it is as follows:
[0040] in, Sampling period DC-side power loss measurement Sampling period The The energy storage execution power of each energy storage branch (positive value indicates discharge, negative value indicates charging). For DC bus capacitors, Sampling period DC bus voltage, For photovoltaic input power, The active power on the AC side of the grid-connected inverter. For DC-side load power, Sampling period The equivalent power loss of lines, filters and converters in the power distribution network.
[0041] S3. When the target energy risk index deviates from the preset safety threshold range, the total energy storage support power is obtained based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, voltage deviation and voltage change rate.
[0042] In this embodiment, the target energy risk index is used to determine the charging and discharging requirements corresponding to the DC bus status parameters. When it is within the safe threshold range, it indicates that the DC bus energy is within the normal operating range, and charging and discharging are not required. The formula for calculating the total energy storage support power is:
[0043] in, Sampling period Total energy storage capacity and These are the maximum discharge power and maximum charging power corresponding to the sum of the energy storage execution power of the energy storage devices, respectively. It is a saturation limiting function. Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, Sampling period DC-side power loss measurement , and These are the control gains corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively.
[0044] S4. Based on the branch operation coefficient, energy storage execution power and branch charge of each energy storage branch, obtain the energy storage allocation coefficient corresponding to each energy storage branch, and adjust the duty cycle of the DC / DC converter of each energy storage branch based on each energy storage allocation coefficient and the total energy storage support power.
[0045] In one possible implementation, obtaining the energy storage allocation coefficient corresponding to each energy storage branch includes: S41. Based on the branch operation coefficient, energy storage execution power, branch charge, maximum charge upper limit, minimum charge lower limit and rated maximum energy storage execution power of each energy storage branch during the current sampling period, obtain the energy storage allocation coefficient of each energy storage branch. S42. Based on the total energy storage support power and the energy storage allocation coefficient of each energy storage branch, obtain the target energy storage execution power of each energy storage branch, and adjust the duty cycle of the DC / DC converter of each energy storage branch based on the target energy storage execution power.
[0046] In this embodiment of the application, when the energy storage device requires discharge support, the first The discharge weight of each energy storage device is determined by the following formula:
[0047] When the energy storage device needs to absorb charge, the first The charging weight of each energy storage device is determined by the following formula:
[0048] in, For the first The discharge weight of the energy storage devices in each energy storage branch. For the first The charging weight of each energy storage device The sampling period; and This indicates the upper and lower limits of the State of Charge (SOC) for charging devices. For the first The branch load of each energy storage device and The first The maximum discharge power and maximum charging power (energy storage execution power) of each energy storage device. No. Branch operation coefficient of each energy storage branch.
[0049] In addition, the branch operation coefficient includes the measurement quality coefficient, communication reliability coefficient, current limiting state coefficient, and temperature safety coefficient, which are expressed by the following formula:
[0050] in, To measure the quality coefficient, For communication reliability coefficient, This is the current limiting state coefficient. The temperature safety factor has a value range of 0 to 1.
[0051] Based on this, the formula for calculating the energy storage allocation coefficient of each energy storage branch is as follows:
[0052] in, For the first Energy distribution coefficient during discharge of each energy storage branch For the first Energy storage distribution coefficient during charging of each energy storage branch.
[0053] The formula for calculating the target energy storage power of the energy storage branch is:
[0054] in, For the first Energy distribution coefficient when each energy storage branch discharges For the first Energy distribution coefficient during charging of each energy storage branch Sampling period Total energy storage capacity For the sampling period, for The energy storage execution power during the sampling period, but from During the process of adjusting the -1 sampling period to the target energy storage execution power, it is necessary to suppress the power change rate of the energy storage execution power, the power surge of the energy storage branch, and the current surge constraint of the bidirectional DC / DC converter.
[0055] In one possible implementation, the duty cycle of the DC / DC converter in each energy storage branch is adjusted based on the target energy storage execution power, including: Based on the rated power change rate range of the energy storage branch during the current sampling period, the power change rate during the process of adjusting the energy storage execution power to the target energy storage execution power is constrained until the energy storage execution power of the energy storage branch is adjusted to the target energy storage execution power. Based on the DC bus voltage and target energy storage power during the current sampling period, the target branch inductor current of the energy storage branch is obtained, and the duty cycle of the DC / DC converter of the energy storage branch is adjusted based on the deviation between the target branch inductor current and the branch inductor current.
[0056] In this embodiment of the application, the expression function for constraining the rate of power change during the process of adjusting the energy storage execution power to the target energy storage execution power is as follows:
[0057] in, and The first The maximum rate of increase in power change and the minimum rate of decrease in power change for each energy storage branch. It is a saturation limiting function. for The target energy storage execution power during the sampling period, its value is... same.
[0058] The expression for the target branch inductor current is:
[0059] in, For the first The target branch inductor current of each energy storage branch is... Target energy storage execution power during the sampling period The corresponding branch inductor current, To prevent small positive numbers from being divided by zero under low voltage.
[0060] The expression for the duty cycle of the DC / DC converter in the energy storage branch is:
[0061] in, For the first The duty cycle of the DC / DC converter in an energy storage device For steady-state duty cycle feedforward term, and These are the proportional gain and integral gain of the inner current loop, respectively. and These are the lower and upper limits of the duty cycle, respectively. For the first The target branch inductor current of each energy storage branch It is a time integration operator.
[0062] In one possible implementation, before step S4, the method further includes: Based on the DC bus capacitor energy deviation, voltage deviation, and AC side active power of the grid-connected inverter, the target AC side active power is obtained. Based on the deviation between the target AC side active power and the AC side active power, the AC side active power is adjusted under the constraint of the power change rate range of the grid-connected inverter.
[0063] In this embodiment of the application, during the adjustment of the AC side active power of the grid-connected inverter, a dual-deviation dynamic iterative correction logic is used. The deviation is updated in real time for each discrete sampling period, and the dynamic correction process is determined by the following formula:
[0064] in, For the revised version The active power of the grid-connected inverter on the AC side during the sampling period. The AC active power before correction. and These are the fixed adjustment gains corresponding to DC bus voltage deviation and energy deviation, respectively. Sampling period DC bus voltage, This is the rated value of the DC bus voltage. This refers to the rated capacitor energy of the DC bus. for DC bus capacitor energy during the sampling period.
[0065] The rate of change of active power of the grid-connected inverter satisfies the following formula:
[0066] in, For the revised version The active power of the grid-connected inverter on the AC side during the sampling period. This is the upper limit of the rate of change of active power on the AC side. This constraint can prevent sudden changes in grid current and power surges on the AC side. The duration of a sampling period.
[0067] like Figure 4 As shown, the AC side active power of the original grid-connected inverter remains constant, while the AC side active power modified by the method in this application dynamically changes with the DC bus capacitor energy. Figure 5 As shown, if the active power on the AC side of the grid-connected inverter is not corrected, all the disturbance power can only be borne by the energy storage branch. In this case, the total energy storage power will remain at its peak for a long time, causing a large instantaneous power surge to the energy storage device. However, after correcting the active power on the AC side, this phenomenon is effectively suppressed. Figure 6As shown, if the active power on the AC side of the grid-connected inverter is not corrected, the DC bus voltage will be subject to significant disturbances and large voltage deviations. This may lead to a decrease in the accuracy of using the target energy risk index to determine whether the DC bus needs to be charged or discharged. However, after correcting the active power on the AC side, the peak value of the DC bus voltage when disturbed is significantly reduced, and the speed of recovery to stability is significantly accelerated. This can effectively improve the dynamic response speed of the DC bus voltage and capacitor energy, and improve the operational stability of the entire distribution network.
[0068] Figure 7 This is a schematic diagram of the structure of the adaptive control system for a multi-DC / DC source energy storage converter provided in the embodiments of this application, as shown below. Figure 7 As shown, the system includes at least: The status parameter acquisition module is used to acquire the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period. The energy risk indicator acquisition module is used to acquire the DC-side power loss of the DC bus, the DC bus capacitor energy deviation, the voltage deviation and voltage change rate, and the target energy risk indicator based on the photovoltaic input power, AC-side active power, DC-side load power, DC bus voltage and DC bus capacitance. The energy storage support power acquisition module is used to acquire the total energy storage support power based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, voltage deviation and voltage change rate when the target energy risk index deviates from the preset safety threshold range. The energy storage allocation coefficient acquisition module is used to obtain the energy storage allocation coefficient corresponding to each energy storage branch based on the branch operation coefficient, energy storage execution power and branch load of each energy storage branch. The DC / DC converter adjustment module is used to adjust the duty cycle of the DC / DC converters of each energy storage branch based on the energy storage allocation coefficient and the total energy storage support power.
[0069] like Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: a processor 801, a communications interface 802, a memory 803, and a communication bus 804. The processor 801, communications interface 802, and memory 803 communicate with each other via the communication bus 804. The processor 801 can call software instructions in the memory 803 to execute the methods described in the above embodiments.
[0070] Furthermore, the logical instructions in the aforementioned memory 803 can be implemented as a software functional device and sold or used as an independent product, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application.
[0071] Based on the methods in the above embodiments, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to execute the methods in the above embodiments.
[0072] Based on the methods in the above embodiments, this application provides a computer program product that, when run on a processor, causes the processor to execute the methods in the above embodiments.
[0073] It is understood that the processor in the embodiments of this application can be a CPU (Central Processing Unit), or other general-purpose processors, DSPs (Digital Signal Processors), ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.
[0074] The method steps in this application embodiment can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, ROM (Read-only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), EEPROM (Electrically Erasable EPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.
[0075] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line DSL) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., SSD (Solid State Disk)).
[0076] It is understood that the various numerical designations used in the embodiments of this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application.
[0077] Those skilled in the art will readily understand that the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. An adaptive control method for a multi-DC / DC source energy storage converter, characterized in that, include: S1. Obtain the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period. The DC bus status parameters include DC bus voltage, DC bus capacitance, AC side active power transmitted to the grid-connected inverter, DC side load power, and photovoltaic input power input by the photovoltaic branch. The branch status parameters include branch operating coefficient, energy storage execution power of the energy storage device connected to the DC bus, branch inductor current, and branch charge. S2. Based on the photovoltaic input power, AC side active power, DC side load power, DC bus voltage and DC bus capacitance, obtain the DC side power loss of the DC bus, DC bus capacitance energy deviation, voltage deviation and voltage change rate, and target energy risk index. S3. When the target energy risk index deviates from the preset safety threshold range, the total energy storage support power is obtained based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, the voltage deviation and the voltage change rate. S4. Based on the branch operation coefficient, energy storage execution power and branch charge of each energy storage branch, obtain the energy storage allocation coefficient corresponding to each energy storage branch, and adjust the duty cycle of the DC / DC converter of each energy storage branch based on each energy storage allocation coefficient and the total energy storage support power.
2. The adaptive control method for multi-DC / DC source energy storage converters according to claim 1, characterized in that, Step S2 includes: S21. Based on the DC bus voltage, DC bus capacitance, DC bus rated voltage and rated capacitor energy during the current sampling period, and the DC bus voltage during the previous sampling period, obtain the DC bus capacitor energy deviation, voltage deviation and voltage change rate, and obtain the target energy risk index based on the DC bus capacitor energy deviation, voltage deviation and voltage change rate. S22. Based on the power balance relationship between the photovoltaic input power, AC side active power, DC side load power, DC bus voltage, DC bus capacitance and each of the energy storage execution powers, obtain the DC side power loss of the DC bus.
3. The adaptive control method for multi-DC / DC source energy storage converters according to claim 2, characterized in that, The calculation formula for obtaining the target energy risk index is as follows: in, Sampling period The target energy risk indicator, The rated DC bus voltage, Sampling period DC bus voltage, Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, This refers to the rated capacitor energy of the DC bus. , and These are the risk weights corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively. The maximum rated rate of change of DC bus voltage is allowed. The time difference between two adjacent sampling periods.
4. The adaptive control method for multi-DC / DC source energy storage converters according to claim 2, characterized in that, The formula for obtaining the total energy storage support power is expressed as follows: in, Sampling period Total energy storage capacity and These are the maximum discharge power and maximum charging power corresponding to the sum of the energy storage execution power of the energy storage devices, respectively. It is a saturation limiting function. Sampling period DC bus voltage deviation, Sampling period DC bus capacitor energy deviation, Sampling period DC-side power loss measurement , and These are the control gains corresponding to DC bus voltage deviation, capacitor energy deviation, and voltage change rate, respectively.
5. The adaptive control method for multi-DC / DC source energy storage converters according to claim 1, characterized in that, The step of obtaining the energy storage allocation coefficient corresponding to each of the energy storage branches includes: Based on the branch operation coefficient, energy storage execution power, branch charge, maximum charge upper limit, minimum charge lower limit and rated maximum energy storage execution power of each energy storage branch during the current sampling period, the energy storage allocation coefficient of each energy storage branch is obtained. Based on the total energy storage support power and the energy storage allocation coefficient of each energy storage branch, the target energy storage execution power of each energy storage branch is obtained, and the duty cycle of the DC / DC converter of each energy storage branch is adjusted based on the target energy storage execution power.
6. The adaptive control method for multi-DC / DC source energy storage converters according to claim 1, characterized in that, The branch operation coefficients include measurement quality coefficient, communication reliability coefficient, current limiting status coefficient, and temperature safety coefficient.
7. The adaptive control method for multi-DC / DC source energy storage converters according to claim 1, characterized in that, The step of adjusting the duty cycle of the DC / DC converter of each energy storage branch based on the target energy storage execution power includes: Based on the rated power change rate range of the energy storage branch during the current sampling period, the power change rate during the process of adjusting the energy storage execution power to the target energy storage execution power is constrained until the energy storage execution power of the energy storage branch is adjusted to the target energy storage execution power. Based on the DC bus voltage and the target energy storage execution power during the current sampling period, the target branch inductor current of the energy storage branch is obtained, and the duty cycle of the DC / DC converter of the energy storage branch is adjusted based on the deviation between the target branch inductor current and the branch inductor current.
8. The adaptive control method for multi-DC / DC source energy storage converters according to claim 1, characterized in that, Before step S4, the method further includes: Based on the DC bus capacitor energy deviation, voltage deviation, and AC side active power of the grid-connected inverter, the target AC side active power is obtained. Based on the deviation between the target AC side active power and the AC side active power, the AC side active power is adjusted under the constraint of the power change rate range of the grid-connected inverter.
9. An adaptive control system for a multi-DC / DC source energy storage converter, used to execute the method as described in any one of claims 1-8, characterized in that, include: The status parameter acquisition module is used to acquire the DC bus status parameters and the branch status parameters of each energy storage branch during the current sampling period. The energy risk index acquisition module is used to acquire the DC-side power loss, DC-side capacitor energy deviation, voltage deviation and voltage change rate, and target energy risk index of the DC bus based on the photovoltaic input power, AC-side active power, DC-side load power, DC bus voltage and DC bus capacitance. The energy storage support power acquisition module is used to acquire the total energy storage support power based on the DC side power loss, the energy storage execution power of each energy storage device, the DC bus capacitor energy deviation, voltage deviation and voltage change rate when the target energy risk index deviates from the preset safety threshold range. The energy storage allocation coefficient acquisition module is used to acquire the energy storage allocation coefficient corresponding to each of the energy storage branches based on the branch operation coefficient, energy storage execution power and branch charge of each of the energy storage branches. The DC / DC converter adjustment module is used to adjust the duty cycle of the DC / DC converter of each energy storage branch based on the energy storage allocation coefficient and the total energy storage support power.
10. An electronic device, characterized in that, include: At least one memory for storing computer programs; At least one processor is configured to execute a program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to perform the method as described in any one of claims 1-8.