Optical storage direct-current flexible system power regulation method and device and direct-current power grid power supply system

Abstract

The invention relates to an optical storage direct-current flexible system power regulation method and device and a direct-current power grid power supply system, in a sampling time period, direct-current bus voltages on a direct-current bus are acquired for multiple times, the voltage change amplitude is calculated according to the multiple direct-current bus voltages, and the power regulation amplitude is determined based on the voltage change amplitude. And adjusting the operation power of the optical storage direct-flexible system according to the power adjustment amplitude. The corresponding power adjustment amplitude is determined based on the change trend of the direct current bus voltage, the operation power of the optical storage direct current flexible system is adjusted according to the power adjustment amplitude, the power can be adjusted based on the direct current bus voltage in a long time, the dynamic response capability is improved, and voltage change perception and power regulation and control of the optical storage direct current flexible system are realized. Long-time supply and demand balance regulation and control are met, and the working reliability of the optical storage direct-flexible system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply systems, and in particular to a power regulation method and device for a photovoltaic-storage-direct-flexible system and a DC power supply system. Background Art

[0002] Driven by the dual development of new power systems, PV-storage, direct-current, and flexible systems are becoming a core driver of building energy transformation. Efficient regulation of flexible loads is key to improving the integration of new energy and enhancing system economics and reliability.

[0003] Traditional PV-storage DC-flexible systems utilize communication-free control of the DC bus voltage. This approach offers advantages such as direct physical signal drive and zero additional cost, improving grid power quality. However, this control method only addresses short-term over-limit conditions (exceeding grid protection thresholds) and cannot maintain long-term supply-demand balance. This results in low reliability for PV-storage DC-flexible systems. Summary of the Invention

[0004] Based on this, it is necessary to address the technical problem that the traditional control method of the photovoltaic storage direct-flexible system causes low working reliability of the photovoltaic storage direct-flexible system, and provide a photovoltaic storage direct-flexible system power regulation method, device and DC grid power supply system to improve the working reliability of the photovoltaic storage direct-flexible system.

[0005] In a first aspect, the present application provides a power regulation method for a photovoltaic-storage-direct-flexible system, wherein the photovoltaic-storage-direct-flexible system includes a photovoltaic module, a photovoltaic converter, a grid-side converter, an energy storage converter, a battery module, and a load, wherein one side of the photovoltaic converter is connected to the photovoltaic module and the other side is connected to a DC bus, one side of the grid-side converter is connected to the grid and the other side is connected to the DC bus, one side of the energy storage converter is connected to the battery module and the other side is connected to the DC bus, and the load is connected to the DC bus;

[0006] The power regulation method of the solar-storage direct-flexible system includes:

[0007] Acquiring the DC bus voltage on the DC bus multiple times within a sampling period;

[0008] Calculating a voltage variation amplitude according to the plurality of DC bus voltages;

[0009] determining a power adjustment amplitude based on the voltage variation amplitude;

[0010] The operating power of the solar-storage direct-flexible system is adjusted according to the power adjustment amplitude.

[0011] In one embodiment, determining the power adjustment amplitude based on the voltage variation amplitude includes:

[0012] A power regulation amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

[0013] In one embodiment, determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes:

[0014] According to a preset voltage-power mapping relationship, a power adjustment amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

[0015] In one embodiment, determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage according to a preset voltage-power mapping relationship includes:

[0016] Based on the voltage-power amplification factor, updating the preset voltage-power mapping relationship;

[0017] Based on the updated preset voltage-power mapping relationship, a power adjustment amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

[0018] In one embodiment, the acquiring the DC bus voltage on the DC bus multiple times within a sampling period includes:

[0019] When the sampling period is longer than the preset voltage sensing time, the voltage acquired during the sampling period is used as the DC bus voltage.

[0020] In one embodiment, determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes:

[0021] When the sampling period is greater than the preset voltage sensing time, the DC bus voltage is updated using the average value of the DC bus voltage obtained during the sampling period;

[0022] A power regulation amplitude is determined based on the voltage variation amplitude and the updated DC bus voltage.

[0023] In one embodiment, determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes:

[0024] Calculating an enabling value of a preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage;

[0025] The power regulation amplitude is determined according to the enable value of the preset gradient judgment function, the voltage variation amplitude and the DC bus voltage.

[0026] In one embodiment, the step of calculating an enable value of a preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage includes:

[0027] Calculating a quotient of the voltage variation amplitude and the DC bus voltage;

[0028] When the quotient is greater than or equal to the preset voltage increase threshold, determining the enable value of the preset gradient judgment function to be a first enable value;

[0029] When the quotient is smaller than the preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be a second enable value.

[0030] In one embodiment, the calculating the quotient of the voltage variation amplitude and the DC bus voltage includes:

[0031] Calculating an absolute value of a difference between a current DC bus voltage and a previous DC bus voltage within the sampling period, and using the absolute value as the voltage variation amplitude;

[0032] A quotient of the absolute value and the current DC bus voltage is calculated.

[0033] In one embodiment, adjusting the operating power of the solar-storage direct-flexible system according to the power adjustment amplitude includes:

[0034] Adjust the operating power of the photovoltaic converter according to the power adjustment amplitude; or,

[0035] Adjust the operating power of the grid-side converter according to the power adjustment amplitude; or,

[0036] Adjust the operating power of the energy storage converter according to the power adjustment amplitude; or,

[0037] The operating power of the load is adjusted according to the power adjustment amplitude.

[0038] In the second aspect, the present application also provides a power regulation device for a photovoltaic storage direct-flexible system, wherein the photovoltaic storage direct-flexible system includes a photovoltaic module, a photovoltaic converter, a grid-side converter, an energy storage converter, a battery module and a load, wherein one side of the photovoltaic converter is connected to the photovoltaic module and the other side is connected to the DC bus, one side of the grid-side converter is connected to the power grid and the other side is connected to the DC bus, one side of the energy storage converter is connected to the battery module and the other side is connected to the DC bus, and the load is connected to the DC bus;

[0039] The power regulation device of the solar-storage direct-flexible system includes:

[0040] A voltage acquisition module, configured to acquire the DC bus voltage on the DC bus multiple times within a sampling period;

[0041] A voltage change calculation module, configured to calculate a voltage change amplitude based on the plurality of DC bus voltages;

[0042] A power change calculation module, configured to determine a power adjustment amplitude based on the voltage change amplitude;

[0043] The power regulation module is used to adjust the operating power of the solar-storage direct-flexible system according to the power regulation amplitude.

[0044] In a third aspect, the present application also provides a DC grid power supply system, including a photovoltaic storage direct-flexible system and a controller, wherein the controller is communicatively connected to the photovoltaic storage direct-flexible system, and the controller is used to implement the above method.

[0045] The above-mentioned power regulation method, device, and DC power grid power supply system for the photovoltaic, storage, and flexible direct current system acquire the DC bus voltage on the DC bus multiple times within a sampling period, calculate the voltage variation amplitude based on the multiple DC bus voltages, determine the power regulation amplitude based on the voltage variation amplitude, and adjust the operating power of the photovoltaic, storage, and flexible direct current system according to the power regulation amplitude. The corresponding power regulation amplitude is determined based on the variation trend of the DC bus voltage, and the operating power of the photovoltaic, storage, and flexible direct current system is adjusted according to the power regulation amplitude. This allows for long-term power regulation based on the DC bus voltage, thereby improving dynamic response capabilities, enabling voltage change perception and power regulation of the photovoltaic, storage, and flexible direct current system, satisfying long-term supply and demand balance regulation, and improving the operational reliability of the photovoltaic, storage, and flexible direct current system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 This is a schematic structural diagram of a solar-storage direct-flexible system in one embodiment;

[0048] Figure 2 1. A schematic flow chart of a power regulation method for a PV-storage direct-flexible system according to an embodiment;

[0049] Figure 3 A schematic flow chart of a power regulation method for a PV-storage direct-flexible system in another embodiment;

[0050] Figure 4 Schematic diagram of a flow chart of a power regulation method for a PV-storage direct-flexible system in another embodiment;

[0051] Figure 5 1 is a flow chart illustrating a step of determining a power adjustment amplitude based on a voltage variation amplitude and a DC bus voltage according to a preset voltage-power mapping relationship in one embodiment;

[0052] Figure 6 A schematic flow chart of a power regulation method for a PV-storage direct-flexible system in yet another embodiment;

[0053] Figure 7 1. A schematic flow chart of a step of determining a power regulation amplitude based on a voltage variation amplitude and a DC bus voltage in one embodiment;

[0054] Figure 8 Schematic diagram of a flow chart of the step of determining a power adjustment amplitude based on a voltage variation amplitude and a DC bus voltage in another embodiment;

[0055] Figure 9 1. A schematic flow chart of a step of calculating an enable value of a preset gradient judgment function according to a voltage variation amplitude and a DC bus voltage in one embodiment;

[0056] Figure 10 1 is a flow chart of the steps of calculating the quotient of the voltage variation amplitude and the DC bus voltage in one embodiment;

[0057] Figure 11 1 is a schematic diagram of a process of voltage filtering in one embodiment;

[0058] Figure 12 Schematic diagram of the structure of a power regulation device for a solar-storage direct-flexible system in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0060] The embodiment of the present application provides a method for adjusting the power of a PV-storage direct-flexible system, which is used to adjust the power of the PV-storage direct-flexible system. Figure 1 As shown, the PV-storage-DC-flexible system includes PV panels, PV converters, grid-side converters, energy storage converters, battery modules and loads. One side of the PV converter is connected to the PV panels, and the other side is connected to the DC bus. One side of the grid-side converter is connected to the grid, and the other side is connected to the DC bus. One side of the energy storage converter is connected to the battery module, and the other side is connected to the DC bus. The load is connected to the DC bus.

[0061] Specifically, the PV-storage-DC-flexible system is an architecture with a DC bus as its energy hub, enabling flexible and coordinated management of photovoltaic power generation, energy storage, grid interaction, and load power supply. In this system, PV panels convert solar energy into DC power. The PV converter is connected to the PV panels on one side and to the system DC bus on the other. Its core function is to track the maximum power point of the PV panels and efficiently feed the DC power generated by the panels into the DC bus. The grid-side converter is connected to the AC grid on one side and to the system DC bus on the other. This converter is a bidirectional converter, enabling bidirectional energy flow between the AC grid and the DC bus. The energy storage converter is connected to the battery module on one side and to the system DC bus on the other. This converter is also a bidirectional converter, responsible for controlling the charging and discharging of the battery module, enabling bidirectional energy transfer between the DC bus and the battery module. The battery module stores DC power and serves as the system's energy buffer. The load is directly connected to the system DC bus. The load can be a native DC load, an AC load powered by a local DC / AC or DC / DC converter, or a DC load of a specific voltage level. For example, the load can be a DC flexible air conditioner. The DC bus serves as the core energy collection and distribution channel for the entire system. The output end of the photovoltaic inverter, the DC end of the grid-side inverter, the DC end of the energy storage inverter, and the input end of the load are all directly connected to the common DC bus. Based on the above structure, the photovoltaic storage DC flexible system coordinates the working status of each inverter through an intelligent energy management system to achieve efficient and flexible energy flow.

[0062] The power regulation method of the PV-storage direct-flexible system can be executed by a terminal or server that is communicatively connected to the PV-storage direct-flexible system. The terminal can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The server can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services. Alternatively, the power regulation method of the PV-storage direct-flexible system can be executed by the photovoltaic converter, grid-side converter, energy storage converter, or load in the PV-storage direct-flexible system, which is not limited here.

[0063] For example, the power regulation method of the PV-storage direct current flexible system is executed by the terminal, PV converter, grid-side converter, energy storage converter or controller in the load. Figure 2 As shown, the power regulation method of the PV-storage direct-flexible system includes the following steps:

[0064] Step 202: Acquire the DC bus voltage on the DC bus multiple times within a sampling period.

[0065] The specific value of the sampling time period can be set according to actual needs and is not limited here.

[0066] During the sampling period, the controller samples the DC bus voltage multiple times, either directly or through other mechanisms, to obtain multiple DC bus voltages. When acquiring the DC bus voltage, the controller can continuously acquire multiple DC bus voltages to facilitate monitoring of changes in the DC bus voltage.

[0067] Step 204 : Calculate the voltage variation amplitude according to the multiple DC bus voltages.

[0068] The magnitude of the voltage change represents the fluctuation of the DC bus voltage.

[0069] After obtaining multiple DC bus voltages, the voltage variation can be calculated. This can be done by calculating the difference between any two DC bus voltages within a sampling period and using the difference as the voltage variation, or by using the absolute value of the difference as the voltage variation. This is not limited here.

[0070] It can be understood that any two DC bus voltages can be the DC bus voltage at the current moment and the DC bus voltage at the previous moment, or can be the DC bus voltage at the current moment and the DC bus voltage at an earlier moment, or can be two DC bus voltages earlier than the current moment, etc., and are not limited here.

[0071] Step 206: Determine a power adjustment range based on the voltage variation range.

[0072] The power regulation trend is consistent with the voltage trend. Generally, the power regulation amplitude is proportional to the voltage change amplitude. As shown in the following formula (1):

[0073] ΔP(t)∝ΔU(t) (1)

[0074] Where ΔP(t) is the power adjustment amplitude, and ΔU(t) is the voltage variation amplitude. After determining the voltage variation amplitude, the power adjustment amplitude corresponding to the voltage variation amplitude can be matched by combining the voltage variation amplitude with a preset correspondence. The preset correspondence can be obtained by fitting based on empirical values ​​or by testing multiple sets of data. The specific method is not limited.

[0075] Step 208: Adjust the operating power of the PV-storage direct-flexible system according to the power adjustment amplitude.

[0076] The operating power of the PV-storage direct-flexible system represents the operating state of the PV-storage direct-flexible system. Adjusting the operating power of the PV-storage direct-flexible system according to the power adjustment range can increase or decrease the operating power of the PV-storage direct-flexible system according to the value of the power adjustment range.

[0077] The operating power of the PV-storage direct-flexible system can be the operating power of some devices in the PV-storage direct-flexible system, for example, the operating power of the photovoltaic converter, the operating power of the grid-side converter, the operating power of the energy storage converter, the operating power of the load, etc.

[0078] In this embodiment, the DC bus voltage on the DC bus is obtained multiple times within a sampling period, the voltage variation amplitude is calculated based on the multiple DC bus voltages, the power adjustment amplitude is determined based on the voltage variation amplitude, and the operating power of the PV-storage-flexible DC system is adjusted based on the power adjustment amplitude. The corresponding power adjustment amplitude is determined based on the variation trend of the DC bus voltage, and the operating power of the PV-storage-flexible DC system is adjusted based on the power adjustment amplitude. This allows for long-term power regulation based on the DC bus voltage, thereby improving dynamic response capabilities, enabling voltage change perception and power regulation of the PV-storage-flexible DC system, satisfying long-term supply and demand balance regulation, and improving the operational reliability of the PV-storage-flexible DC system.

[0079] In one scalable embodiment, step 208 includes the step of adjusting the operating power of the photovoltaic converter based on the power regulation amplitude. Based on the power regulation method for a PV-storage DC-flexible system provided in this embodiment of the present application, the photovoltaic converter can regulate its operating power based on changes in the DC bus voltage, thereby adjusting the discharge power of the photovoltaic modules. Alternatively, step 208 includes the step of adjusting the operating power of the grid-side converter based on the power regulation amplitude, thereby adjusting the grid-side converter's operating power based on changes in the DC bus voltage, thereby adjusting the discharge power of the grid. Alternatively, step 208 includes the step of adjusting the operating power of the energy storage converter based on the power regulation amplitude, thereby adjusting the energy storage converter's operating power based on changes in the DC bus voltage, thereby adjusting the charge and discharge power of the photovoltaic modules. Alternatively, step 208 includes the step of adjusting the operating power of the load based on the power regulation amplitude, thereby adjusting the load's own operating power based on changes in the DC bus voltage, thereby better achieving source-load interaction and supply-demand balance. This facilitates achieving dynamic balance in the PV-storage DC-flexible system and improves the power quality of the system.

[0080] In an exemplary embodiment, Figure 3 As shown, step 206 includes step 306: determining a power regulation amplitude based on the voltage variation amplitude and the DC bus voltage.

[0081] The method of determining the power adjustment range based on the voltage variation range is not the only one. In an exemplary embodiment, the power adjustment range is determined by combining the voltage variation range and the DC bus voltage.

[0082] The ratio of the voltage variation amplitude to the DC bus voltage can represent the rate of change of the DC bus voltage. The ratio of the power regulation amplitude to the operating power can represent the rate of change of the power. The rate of change of the DC bus voltage and the rate of change of the power are correlated and can be equal or proportional, for example. Therefore, after determining the voltage variation amplitude and the DC bus voltage, the operating power of the device to be power regulated can be obtained to calculate the power regulation amplitude.

[0083] It should be understood that when determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage, the DC bus voltage at this time can be one of the DC bus voltages obtained in the above steps, and the DC bus voltage corresponding to the current moment is recorded. Alternatively, the DC bus voltage at this time can also be a DC bus voltage calculated based on multiple DC bus voltages obtained in the above steps, and can be determined based on actual needs.

[0084] In this embodiment, the power regulation range is determined based on the voltage variation range and the DC bus voltage. Comprehensive consideration of the impact of the voltage variation range and the DC bus voltage on the power regulation range can improve the accuracy of the calculated power regulation range.

[0085] In an exemplary embodiment, Figure 4 As shown, step 306 includes step 406: determining the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage according to a preset voltage-power mapping relationship.

[0086] Among them, the preset voltage-power mapping relationship can be obtained by fitting based on empirical values, or by calculating based on detection values, which is not limited here. The preset voltage-power mapping relationship can be determined and adjusted according to actual conditions. In this embodiment, the preset voltage-power mapping relationship is: the quotient of the voltage variation amplitude and the DC bus voltage, and the quotient of the power regulation amplitude and the operating power, and the two quotients are proportional. Therefore, according to the preset voltage-power mapping relationship, the specific method of determining the power regulation amplitude based on the voltage variation amplitude and the DC bus voltage can be to calculate the quotient of the voltage variation amplitude and the DC bus voltage, and the product of this quotient and the operating power is the power regulation amplitude.

[0087] In this embodiment, according to the preset voltage-power mapping relationship, the power adjustment range is determined based on the voltage variation range and the DC bus voltage, which can quickly determine the power adjustment range and improve the response speed of power control.

[0088] In an exemplary embodiment, Figure 5 As shown, step 406 includes step 506 and step 508.

[0089] Step 506: Update the preset voltage-power mapping relationship based on the voltage-power amplification factor.

[0090] During the power regulation process, the power supply may be subject to the adjustable voltage range, the operating voltage range of the device to be power regulated (e.g., load, photovoltaic converter, grid-side converter, or energy storage converter), and the adjustable power range boundary of the device to be power regulated (e.g., load, photovoltaic converter, grid-side converter, or energy storage converter). Therefore, a voltage-power amplification factor is introduced, and the preset voltage-power mapping relationship is updated based on the voltage-power amplification factor. The updated preset voltage-power mapping relationship is shown in the following formula (2):

[0091]

[0092] Among them, K vp is the voltage-power amplification factor, ΔP(t) is the power regulation amplitude, P(t) is the real-time power of the device to be power regulated, ΔU(t) is the voltage variation amplitude, and U(t) is the real-time DC bus voltage of the power supply.

[0093] Furthermore, the voltage-power amplification factor K vp The calculation method can be shown in the following formula (3):

[0094]

[0095] Wherein, ΔP is the adjustable power range of the device to be power regulated, P0 is the rated power of the device to be power regulated, ΔU is the voltage variation range, and U0 is the rated DC bus voltage or reference voltage of the power supply.

[0096] Step 508 : Determine a power adjustment range based on the updated preset voltage-power mapping relationship, the voltage variation range, and the DC bus voltage.

[0097] Based on the updated preset voltage-power mapping relationship, the power adjustment range can be obtained based on the voltage change range and a certain ratio. The specific calculation method can be obtained from the above formulas (2)-(3) and will not be repeated here.

[0098] In this embodiment, a preset voltage-power mapping relationship is updated based on the voltage-power amplification factor. Based on the updated preset voltage-power mapping relationship, the power adjustment range is determined based on the voltage variation and the DC bus voltage. This allows the resulting power adjustment range to meet the limits of the power supply's adjustable voltage range, the operating voltage range of the device to be power-regulated, and the adjustable power range of the device to be power-regulated, thereby improving the safety and effectiveness of power regulation.

[0099] In an exemplary embodiment, Figure 6 As shown, step 204 includes step 604 .

[0100] Step 604 : When the sampling period is longer than the preset voltage sensing time, the voltage acquired during the sampling period is used as the DC bus voltage.

[0101] The preset voltage sensing time is a preset fixed value, and the specific value can be determined according to actual needs and is not limited here.

[0102] If the sampling period is too short, the acquired voltage may be a transient voltage, which may be affected by some factors and may be abnormally large or small. If the sampling period is longer than the preset voltage sensing time, it indicates that the sampling period is long. Using the voltage acquired during this long sampling period as the DC bus voltage can obtain a more stable DC bus voltage.

[0103] The DC bus voltage may experience real-time transients due to voltage disturbances caused by power clutter, PV switching, and energy storage charging and discharging switching in the PV-storage-direct-flexible system. If power regulation is performed based on the power regulation amplitude derived from the transient DC bus voltage, this may cause power regulation disruption. Therefore, by introducing a preset voltage sensing time, the DC bus voltage used for power regulation is only obtained as the command voltage when the sampling period is greater than the preset voltage sensing time. The voltage obtained during the sampling period is used as the DC bus voltage, thus avoiding power surges caused by transient voltage changes.

[0104] In this embodiment, when the sampling period is longer than the preset voltage sensing time, the voltage acquired during the sampling period is used as the DC bus voltage. This allows for a more stable DC bus voltage to be acquired, avoiding power surges caused by transient voltage changes, thereby improving the stability and accuracy of power regulation.

[0105] In an exemplary embodiment, Figure 7 As shown, step 306 includes step 706 and step 708 .

[0106] in:

[0107] Step 706 : When the sampling period is longer than the preset voltage sensing time, the DC bus voltage is updated using the average value of the DC bus voltages acquired during the sampling period.

[0108] If the sampling period is longer than the preset voltage sensing time, the sampling period is long, and the DC bus voltage obtained during the long sampling period is relatively stable. The average value of the DC bus voltage obtained during the sampling period is calculated and used as the DC bus voltage for subsequent calculation of the power regulation amplitude.

[0109] Step 708: Determine a power adjustment range based on the voltage variation range and the updated DC bus voltage.

[0110] When determining the power regulation amplitude, the power regulation amplitude is determined based on the voltage variation amplitude and the updated DC bus voltage. The power regulation amplitude can be calculated based on a relatively intermediate and stable DC bus voltage value, and then power regulation is performed, thereby improving the accuracy of power regulation.

[0111] In this embodiment, when the sampling time period is greater than the preset voltage sensing time, the DC bus voltage is updated using the average value of the DC bus voltage obtained during the sampling time period, and the power regulation amplitude is determined based on the voltage change amplitude and the updated DC bus voltage, which can improve the accuracy of power regulation.

[0112] In an exemplary embodiment, Figure 8 As shown, step 306 includes step 806 and step 808 .

[0113] in:

[0114] Step 806 : Calculate an enable value of a preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage.

[0115] The preset gradient judgment function may be used to judge the relationship between the voltage variation amplitude and the DC bus voltage.

[0116] A specific method of calculating the enable value of the preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage may be to calculate the quotient of the voltage variation amplitude and the DC bus voltage, and different quotients correspond to different enable values ​​of the preset gradient judgment function.

[0117] Step 808 : Determine the power adjustment range according to the enabled value of the preset gradient judgment function, the voltage variation range, and the DC bus voltage.

[0118] When determining the power adjustment range, a preset gradient judgment function is introduced. Only when the enabled value of the preset gradient judgment function meets certain conditions can the power adjustment range be determined based on the enabled value of the preset gradient judgment function, the voltage variation range, and the DC bus voltage. This is equivalent to adding an enabling condition related to the voltage amplitude to the power adjustment conditions. If the enabled value of the preset gradient judgment function, calculated based on the voltage variation range and the DC bus voltage, does not meet the conditions, the power adjustment range cannot be determined, and power adjustment cannot be enabled.

[0119] In this embodiment, an enable value of a preset gradient judgment function is calculated based on the voltage variation and the DC bus voltage. The power adjustment range is determined based on the enable value of the preset gradient judgment function, the voltage variation, and the DC bus voltage. Introducing the preset gradient judgment function when determining the power adjustment range helps improve the effectiveness of the power adjustment range.

[0120] In an expandable embodiment, the method for determining the power adjustment range can also combine a preset voltage-power mapping relationship and a preset gradient judgment function. According to the preset voltage-power mapping relationship and the preset gradient judgment function, the power adjustment range is determined based on the voltage variation range and the DC bus voltage. This helps to make the obtained power adjustment range more suitable for actual conditions.

[0121] In an exemplary embodiment, Figure 9 As shown, step 806 includes steps 902 to 906.

[0122] in:

[0123] Step 902: Calculate the quotient of the voltage variation amplitude and the DC bus voltage.

[0124] The voltage variation amplitude can be the difference between the current DC bus voltage and the DC bus voltage obtained at an earlier time, or the absolute value of the difference. The DC bus voltage can be the current DC bus voltage. Calculating the quotient of the voltage variation amplitude and the DC bus voltage can represent the change in the DC bus voltage.

[0125] Step 904 : When the quotient is greater than or equal to the preset voltage increase threshold, determine that the enable value of the preset gradient judgment function is the first enable value.

[0126] The preset voltage increase threshold value is not unique and can be set based on actual conditions. For example, the preset voltage increase threshold value Z can be set to 0 < Z ≤ 1. For example, if the grid-side converter voltage adjustable range is 80% to 105% of 800 VDC, the voltage increase threshold value Z can be set to 0 < Z ≤ 0.25. The specific value can be determined based on the voltage sampling accuracy.

[0127] When the quotient is greater than or equal to the preset voltage increase threshold, it indicates that the DC bus voltage changes significantly and rapidly, and the enable value of the preset gradient judgment function is determined to be the first enable value. The first enable value can be a value that enables the calculation of the power adjustment amplitude.

[0128] Step 906 : When the quotient is less than the preset voltage increase threshold, determine that the enable value of the preset gradient judgment function is a second enable value.

[0129] If the quotient is less than the preset voltage increase threshold, indicating that the DC bus voltage is changing slowly and relatively small, the enable value of the preset gradient judgment function is determined to be a second enable value. The second enable value is different from the first enable value and may be a value that invalidates the calculation of the power adjustment amplitude.

[0130] The specific values ​​of the first enable value and the second enable value can be determined based on the role of the preset gradient judgment function in calculating the power adjustment amplitude. For example, if the enable value of the preset gradient judgment function is a coefficient that needs to be multiplied during the calculation of the power adjustment amplitude, the first enable value can be 1 and the second enable value can be 0. It is understood that in other embodiments, the values ​​of the first enable value and the second enable value can also be other values, which are not limited here.

[0131] In this embodiment, the quotient of the voltage variation amplitude and the DC bus voltage is calculated. If the quotient is greater than or equal to a preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be a first enable value. If the quotient is less than the preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be a second enable value. Thus, the enable value of the preset gradient judgment function can be determined based on the quotient of the voltage variation amplitude and the DC bus voltage. Based on the DC bus voltage variation, power calculation and power regulation can be enabled when the voltage changes significantly and rapidly, thereby filtering out the impact of smooth voltage fluctuations on power calculation and power regulation.

[0132] In an exemplary embodiment, Figure 10 As shown, step 902 includes step 1002 and step 1004. Among them:

[0133] Step 1002 : Calculate the absolute value of the difference between the current DC bus voltage and the previous DC bus voltage within the sampling period, and use the absolute value as the voltage variation amplitude.

[0134] Step 1004 , calculating the quotient of the absolute value and the current DC bus voltage.

[0135] To calculate the voltage variation, the current DC bus voltage and the previous DC bus voltage during the sampling period are used as the reference. The absolute value of the difference between the current DC bus voltage and the previous DC bus voltage during the sampling period is used as the voltage variation. The quotient of this absolute value and the current DC bus voltage is then calculated to determine the most recent DC bus voltage fluctuation.

[0136] In this embodiment, the absolute value of the difference between the current DC bus voltage and the previous DC bus voltage during the sampling period is calculated. This absolute value is used as the voltage variation amplitude, and the quotient of this absolute value and the current DC bus voltage is calculated. This facilitates the subsequent determination of the enable value of a preset gradient judgment function based on the most recent DC bus voltage fluctuations, and further calculation of the power adjustment amplitude, thereby improving the timeliness of power regulation.

[0137] In order to better understand the above embodiment, a detailed explanation is given below in conjunction with a specific embodiment. Figure 1 As shown, the PV-storage-DC-flexible system includes PV panels, PV converters, grid-side converters, energy storage converters, battery modules and loads. One side of the PV converter is connected to the PV panels, and the other side is connected to the DC bus. One side of the grid-side converter is connected to the grid, and the other side is connected to the DC bus. One side of the energy storage converter is connected to the battery module, and the other side is connected to the DC bus. The load is connected to the DC bus.

[0138] The power regulation method for a PV-storage, direct-current, and flexible system is executed by the load, specifically by the controller within the load, which regulates its own power. This power regulation method is primarily based on the mapping relationship between voltage and load power. The orderly stability of load power regulation is strongly correlated with its sensitivity to voltage. Therefore, the impact of voltage fluctuations in different operating states must be considered, and a voltage signal filtering algorithm designed in both timing and amplitude dimensions is required.

[0139] The power regulation method for a PV-storage-DC-flexible system uses the grid-side converter to adjust the DC bus voltage. The load monitors changes in the DC bus voltage and adjusts its own operating power up or down based on the magnitude of the DC bus voltage change. The power regulation trend is consistent with the voltage trend, with the load power change value no less than the monitoring accuracy value, and the load power change time no less than the system trigger time. Taking an 800VDC flexible DC multi-link system as an example, the grid-side converter voltage regulation range is 80% to 105% of the rated voltage, and the load power is adjustable within the full rated power range.

[0140] ΔP(t)∝ΔU(t) (1)

[0141] The actual voltage-power regulation is limited by the adjustable voltage range of the power supply, the load operating voltage range and the load adjustable power range. The voltage-power amplification factor K is introduced. vp , based on the voltage adjustment amplitude, it can be amplified according to the amplification factor to obtain the corresponding power adjustment amplitude.

[0142]

[0143] Where: ΔP is the adjustable range of load power, P0 is the rated power of the load, ΔU is the voltage variation range, and U0 is the rated DC bus voltage or reference voltage of the power supply.

[0144] Based on the voltage-power amplification factor K vp , the voltage-power mapping relationship is formulated as follows:

[0145]

[0146] Where: ΔP(t) is the load power adjustment amplitude, P(t) is the load real-time power, ΔU(t) is the voltage adjustment amplitude, and U(t) is the real-time DC bus voltage of the power supply.

[0147] The load monitoring DC bus voltage needs to filter out voltage disturbances caused by power clutter, photovoltaic switching, energy storage charging and discharging switching, etc., to avoid real-time transients causing load power regulation disorder. Introducing voltage sensing time T vpd , gradient judgment function G(ΔU, U, Z). Voltage sensing time T vpd The time threshold of the load sensing voltage is t, and the continuous sampling time t exceeds T vpd Only then can the command voltage for power regulation be calculated, which can be set to s level or min level to avoid sudden changes in load power caused by transient voltage changes. The gradient judgment function G(ΔU, U, Z) is the enabling value of the load-sensing voltage in amplitude. When the specified judgment conditions are met, power regulation is enabled. Otherwise, it is prohibited. The voltage increase threshold Z is set in G(ΔU, U, Z), which is the threshold of the load-sensing voltage in amplitude. When the voltage increase or decrease amplitude exceeds the threshold, G(ΔU, U, Z) can be made effective, that is, power regulation can be enabled. The voltage increase threshold Z can be set to 0<Z≤1. According to the grid-side converter voltage adjustable range of 80% to 105% of 800VDC, the setting range can be 0<Z≤0.25. The specific value can be determined in combination with the voltage sampling accuracy to filter voltage measurement errors and smooth voltage fluctuations. After the voltage signal is "filtered" and conditioned, the command voltage U for load power regulation can be obtained. ord , and thus ΔP is calculated.

[0148] Furthermore, the dynamic voltage-power mapping relationship is as follows: Specifically:

[0149]

[0150] Where: U ord，1 is the previous command voltage, U ord，n is the current command voltage.

[0151] Specifically, the process of voltage filtering is as follows: Figure 11 As shown, the specific steps include:

[0152] 1. First set the voltage sensing time T vpd , the sampling step is t, at T vpd The DC bus voltage is recorded within a period of time, filtered by voltage sensing, and sampled cyclically. When the sampling is completed within this period of time, the average value is set as the command voltage value.

[0153] 2. The voltage sensing filter is at T vpd The absolute value of the difference between the previous and next internal sampling voltages and the current voltage value is compared with the set voltage increase threshold Z. When the current value is greater than the next value, it is recorded as one state, otherwise, it is recorded as another state. Through cyclic comparison, only when it is within T vpd When the voltage is in a certain state, the command voltage calculation is started. Otherwise, the initialization is continued to re-collect the DC bus voltage value.

[0154] 3. Repeat steps 1 and 2, and solve the load power control value ΔP based on the voltage-power mapping function according to the calculated two command voltage values.

[0155] 4. The load adjusts power according to the load power control value.

[0156] Based on the power regulation method of the photovoltaic storage direct-flexible system provided in the embodiment of the present application, a voltage-power mapping relationship model is established to achieve a quantitative characterization of the flexible load power regulation method based on the DC bus voltage. Through the voltage perception filter design, the influence of the fluctuation of the collected voltage in different operating states is taken into account, and a voltage signal filtering algorithm in two dimensions of timing and amplitude is designed. A voltage signal filtering method based on trend judgment within a limited perception time is designed to suppress unstable signals within ±5% of the real-time voltage value while ensuring dynamic response. The flexible DC load can perceive and regulate long-term and short-term voltage changes. The established voltage-power mapping relationship model and filtering method have a transient voltage fluctuation range of 96.09%-101.61%. Under the nominal voltage condition, the load power regulation can be unaffected, the response time is 14s, and the tracking accuracy reaches 98.8%.

[0157] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0158] Based on the same inventive concept, embodiments of the present application also provide a power regulation device for a PV-storage, direct-flexible system for implementing the aforementioned power regulation method for a PV-storage, direct-flexible system. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the power regulation device for a PV-storage, direct-flexible system provided below can be found in the aforementioned limitations of the power regulation method for a PV-storage, direct-flexible system, and will not be further elaborated here.

[0159] In an exemplary embodiment, a power regulation device for a photovoltaic-storage-direct-flexible system is provided. The photovoltaic-storage-direct-flexible system includes photovoltaic modules, photovoltaic converters, grid-side converters, energy storage converters, battery modules, and loads. One side of the photovoltaic converter is connected to the photovoltaic modules and the other side is connected to the DC bus. One side of the grid-side converter is connected to the grid and the other side is connected to the DC bus. One side of the energy storage converter is connected to the battery module and the other side is connected to the DC bus. The load is connected to the DC bus. Figure 12 As shown, the power regulation device of the PV-storage direct-flexible system includes: a voltage acquisition module, a voltage change calculation module, a power change calculation module and a power regulation module, wherein:

[0160] The voltage acquisition module 1202 is used to obtain the DC bus voltage on the DC bus multiple times within a sampling period;

[0161] A voltage variation calculation module 1204 is configured to calculate a voltage variation amplitude based on a plurality of DC bus voltages;

[0162] A power change calculation module 1206 is configured to determine a power adjustment range based on a voltage change range;

[0163] The power adjustment module 1208 is used to adjust the operating power of the solar-storage direct-flexible system according to the power adjustment amplitude.

[0164] In an exemplary embodiment, the power change calculation module is further configured to determine a power regulation amplitude based on the voltage change amplitude and the DC bus voltage.

[0165] In an exemplary embodiment, the power change calculation module is further configured to determine the power adjustment amplitude based on the voltage change amplitude and the DC bus voltage according to a preset voltage-power mapping relationship.

[0166] In an exemplary embodiment, the power change calculation module is also used to update the preset voltage-power mapping relationship based on the voltage-power amplification factor; based on the updated preset voltage-power mapping relationship, determine the power adjustment amplitude based on the voltage change amplitude and the DC bus voltage.

[0167] In an exemplary embodiment, the voltage acquisition module is further configured to use the voltage acquired during the sampling period as the DC bus voltage when the sampling period is greater than a preset voltage sensing time.

[0168] In an exemplary embodiment, the power change calculation module is also used to update the DC bus voltage using the average value of the DC bus voltage obtained during the sampling time period when the sampling time period is greater than the preset voltage sensing time; and determine the power adjustment amplitude based on the voltage change amplitude and the updated DC bus voltage.

[0169] In an exemplary embodiment, the power change calculation module is also used to calculate the enable value of the preset gradient judgment function based on the voltage change amplitude and the DC bus voltage; and determine the power adjustment amplitude based on the enable value of the preset gradient judgment function, the voltage change amplitude and the DC bus voltage.

[0170] In an exemplary embodiment, the power change calculation module is also used to calculate the quotient of the voltage change amplitude and the DC bus voltage; when the quotient is greater than or equal to the preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be the first enable value; when the quotient is less than the preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be the second enable value.

[0171] In an exemplary embodiment, the power change calculation module is further used to calculate the absolute value of the difference between the current DC bus voltage and the previous DC bus voltage during the sampling time period, and use the absolute value as the voltage change amplitude; calculate the quotient of the absolute value and the current DC bus voltage.

[0172] In an exemplary embodiment, the power regulation module is also used to adjust the operating power of the photovoltaic inverter according to the power regulation amplitude; or, to adjust the operating power of the grid-side inverter according to the power regulation amplitude; or, to adjust the operating power of the energy storage inverter according to the power regulation amplitude; or, to adjust the operating power of the load according to the power regulation amplitude.

[0173] Each module in the aforementioned power regulation device for a PV-storage direct-flexible system can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor within a computer device in hardware form, or stored in a computer device memory in software form, allowing the processor to call and execute the corresponding operations of each module.

[0174] In one embodiment, a DC grid power supply system is provided, including a photovoltaic storage direct-flexible system and a controller. The controller is communicatively connected to the photovoltaic storage direct-flexible system, and the controller is used to implement the method of any of the above embodiments.

[0175] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile memory and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable logic unit (PLC), a data processing logic unit based on quantum computing, an artificial intelligence (AI) processor, and the like.

[0176] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0177] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A power regulation method for a PV-storage direct-flexible system, characterized in that: The photovoltaic storage direct-flexible system includes a photovoltaic module, a photovoltaic converter, a grid-side converter, an energy storage converter, a battery module and a load. One side of the photovoltaic converter is connected to the photovoltaic module, and the other side is connected to the DC bus. One side of the grid-side converter is connected to the power grid, and the other side is connected to the DC bus. One side of the energy storage converter is connected to the battery module, and the other side is connected to the DC bus. The load is connected to the DC bus. The power regulation method of the solar-storage direct-flexible system includes: Acquiring the DC bus voltage on the DC bus multiple times within a sampling period; Calculating a voltage variation amplitude according to the plurality of DC bus voltages; determining a power adjustment amplitude based on the voltage variation amplitude; The operating power of the solar-storage direct-flexible system is adjusted according to the power adjustment amplitude.

2. The method according to claim 1, characterized in that The determining of the power adjustment amplitude based on the voltage variation amplitude includes: A power regulation amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

3. The method according to claim 2, characterized in that The determining of the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes: According to a preset voltage-power mapping relationship, a power adjustment amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

4. The method according to claim 3, characterized in that The determining of the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage according to a preset voltage-power mapping relationship includes: Based on the voltage-power amplification factor, updating the preset voltage-power mapping relationship; Based on the updated preset voltage-power mapping relationship, a power adjustment amplitude is determined based on the voltage variation amplitude and the DC bus voltage.

5. The method according to claim 2, characterized in that The step of acquiring the DC bus voltage on the DC bus multiple times within a sampling time period includes: When the sampling period is longer than the preset voltage sensing time, the voltage acquired during the sampling period is used as the DC bus voltage.

6. The method according to claim 5, characterized in that The determining of the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes: When the sampling period is greater than the preset voltage sensing time, the DC bus voltage is updated using the average value of the DC bus voltage obtained during the sampling period; A power regulation amplitude is determined based on the voltage variation amplitude and the updated DC bus voltage.

7. The method according to claim 2, characterized in that The determining of the power adjustment amplitude based on the voltage variation amplitude and the DC bus voltage includes: Calculating an enabling value of a preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage; The power regulation amplitude is determined according to the enable value of the preset gradient judgment function, the voltage variation amplitude and the DC bus voltage.

8. The method according to claim 7, characterized in that The step of calculating an enable value of a preset gradient judgment function according to the voltage variation amplitude and the DC bus voltage includes: Calculating a quotient of the voltage variation amplitude and the DC bus voltage; When the quotient is greater than or equal to the preset voltage increase threshold, determining the enable value of the preset gradient judgment function to be a first enable value; When the quotient is smaller than the preset voltage increase threshold, the enable value of the preset gradient judgment function is determined to be a second enable value.

9. The method according to claim 8, characterized in that The calculating a quotient of the voltage variation amplitude and the DC bus voltage includes: Calculating an absolute value of a difference between a current DC bus voltage and a previous DC bus voltage within the sampling period, and using the absolute value as the voltage variation amplitude; A quotient of the absolute value and the current DC bus voltage is calculated.

10. The method according to claim 1, characterized in that The step of adjusting the operating power of the solar-storage direct-flexible system according to the power adjustment amplitude includes: Adjust the operating power of the photovoltaic converter according to the power adjustment amplitude; or, Adjust the operating power of the grid-side converter according to the power adjustment amplitude; or, Adjust the operating power of the energy storage converter according to the power adjustment amplitude; or, The operating power of the load is adjusted according to the power adjustment amplitude.

11. A power regulation device for a solar-storage direct-flexible system, characterized in that: The photovoltaic storage direct-flexible system includes a photovoltaic module, a photovoltaic converter, a grid-side converter, an energy storage converter, a battery module and a load. One side of the photovoltaic converter is connected to the photovoltaic module, and the other side is connected to the DC bus. One side of the grid-side converter is connected to the power grid, and the other side is connected to the DC bus. One side of the energy storage converter is connected to the battery module, and the other side is connected to the DC bus. The load is connected to the DC bus. The power regulation device of the solar-storage direct-flexible system includes: A voltage acquisition module, configured to acquire the DC bus voltage on the DC bus multiple times within a sampling period; A voltage change calculation module, configured to calculate a voltage change amplitude based on the plurality of DC bus voltages; A power change calculation module, configured to determine a power adjustment amplitude based on the voltage change amplitude; The power regulation module is used to adjust the operating power of the solar-storage direct-flexible system according to the power regulation amplitude.

12. A DC power supply system, characterized in that: It includes a solar-storage, direct-flexible system and a controller, the controller is communicatively connected to the solar-storage, direct-flexible system, and the controller is used to implement the method described in any one of claims 1-10.

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