Photovoltaic-storage microgrid systems and their constraint control methods, electronic devices, and storage media

Abstract

This invention relates to the field of power electronic control technology, and discloses a photovoltaic-storage microgrid system and its constraint control method, electronic equipment, and storage medium. It not only configures a photovoltaic-storage microgrid system integrating photovoltaic and energy storage stability, but also achieves stable photovoltaic power output by controlling the photovoltaic inverter to perform maximum power point tracking (MPPT). In particular, it distinguishes between grid-connected and off-grid scenarios by real-time monitoring of the grid power switching switch. Based on this, and combining the photovoltaic scenario conditions and real-time load conditions, it performs separate constraint control on the photovoltaic-storage microgrid system under grid-connected and off-grid scenarios, thereby achieving stable operation of the photovoltaic-storage microgrid system.

Description

Technical Field

[0001] This invention relates to the field of power electronic control technology, and in particular to a photovoltaic-storage microgrid system and its constraint control method, electronic equipment, and computer-readable storage medium. Background Technology

[0002] A microgrid is a small-scale power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, loads, monitoring and protection devices, etc. Generally speaking, a microgrid is an autonomous system capable of self-control, protection, and management. It can operate in parallel with the external power grid or in isolation; a common example is a photovoltaic-storage microgrid. In recent years, although the application of photovoltaic-storage microgrids in power systems has become increasingly widespread, the increasing complexity of their operating scenarios and the diversification of their operating modes have led to significant challenges to their stability during operation. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a photovoltaic-storage microgrid system and its constraint control method, electronic equipment, and storage medium, which can achieve stable operation of the photovoltaic-storage microgrid system.

[0004] In a first aspect, embodiments of the present invention provide a photovoltaic-storage microgrid system, including an energy storage converter, a photovoltaic inverter, an isolation transformer, battery units, photovoltaic units, and a mains power switching switch. The battery units are connected to the mains power switching switch via the energy storage converter. The photovoltaic units are connected to the mains power switching switch sequentially via the photovoltaic inverter and the isolation transformer. The AC port of the energy storage converter is connected to the AC port of the photovoltaic inverter via the isolation transformer. The mains power switching switch is used to connect to the mains power input. A load port for supplying power to the load is provided between the mains power switching switch and the isolation transformer.

[0005] Secondly, embodiments of the present invention provide a constraint control method for a photovoltaic-storage microgrid system as described in the first aspect, comprising the following steps:

[0006] Step S1: Control the photovoltaic inverter to perform maximum power point tracking (MPPT) and monitor the opening and closing status of the mains power switching switch in real time.

[0007] Step S2: If the mains power switching switch is in the closed state, generate a grid-connected constraint control strategy for the photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power and the real-time mains electricity price; otherwise, proceed to step S3.

[0008] The photovoltaic power is obtained by converting the DC energy input to the photovoltaic unit by the photovoltaic inverter, and the load power is the power required for the load to operate as monitored through the load port.

[0009] Step S3: Based on the obtained relationship between photovoltaic power and load power, generate an off-grid constraint control strategy for the photovoltaic-storage microgrid system.

[0010] Optionally, in one embodiment of the present invention, step S2, which generates a grid-connected constraint control strategy for the photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power and the real-time grid electricity price, includes the following steps:

[0011] Step S21: When the photovoltaic power is greater than or equal to the load power and the mains electricity price is at its peak, control the energy storage converter to enter standby mode and supply power to the load separately based on the photovoltaic power, and connect to the grid with the first photovoltaic surplus power, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power;

[0012] or,

[0013] Step S22: When the photovoltaic power is less than the load power and the mains electricity price is at its peak, control the energy storage converter to enter the discharge state to output discharge power, and perform mixed power supply for the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power;

[0014] or,

[0015] Step S23: When the photovoltaic power is greater than or equal to the load power and the mains electricity price is in a valley, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state, and the energy storage converter is charged based on the first photovoltaic surplus power.

[0016] or,

[0017] Step S24: When the photovoltaic power is less than the load power and the mains electricity price is in a low-price period, control the energy storage converter to enter standby mode and provide separate power supply to the load based on the mains electricity.

[0018] Optionally, in one embodiment of the present invention, when the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S23, after charging the energy storage converter based on the first photovoltaic surplus power, further includes the following step:

[0019] Step S231: Control the energy storage converter to enter standby mode and connect to the grid using the second photovoltaic surplus power, wherein the second photovoltaic surplus power is the difference between the first photovoltaic surplus power and the charging power.

[0020] Optionally, in one embodiment of the present invention, step S3 includes the following steps:

[0021] Step S31: When the photovoltaic power is less than the load power, control the energy storage converter to enter the discharge state to output discharge power, and perform mixed power supply for the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power;

[0022] or,

[0023] Step S32: When the photovoltaic power is greater than or equal to the load power, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state. The energy storage converter is charged based on the first photovoltaic surplus power, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power.

[0024] Optionally, in one embodiment of the present invention, when the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S32 further includes the following steps:

[0025] Step S321: Obtain the AC bus voltage of the energy storage converter through the AC port of the energy storage converter;

[0026] Step S322: Based on the relationship between the AC bus voltage and the predetermined AC bus rated voltage and AC bus threshold voltage, the photovoltaic inverter is controlled for power output, wherein the AC bus threshold voltage is greater than the AC bus rated voltage.

[0027] Optionally, in one embodiment of the present invention, step S322 includes the following steps:

[0028] Step S3221: When the AC bus voltage is less than or equal to the AC bus rated voltage, control the photovoltaic inverter to output the rated power of the photovoltaic inverter; or, when the AC bus voltage is greater than or equal to the AC bus threshold voltage, control the photovoltaic inverter not to output power; or, when the AC bus voltage is greater than the AC bus rated voltage and less than the AC bus threshold voltage, control the photovoltaic inverter to output variable power, wherein the variable power decreases linearly over time from the rated power of the photovoltaic inverter to zero.

[0029] Optionally, in one embodiment of the present invention, when the energy storage converter adopts a current-limiting charging method, step S32 further includes the following steps:

[0030] Step S323: Based on the charging power and the rated power of the photovoltaic inverter, control the energy storage converter to maintain the AC bus voltage at... ,in, The expression is as follows:

[0031] ;

[0032] The rated voltage of the AC bus is... The AC bus threshold voltage, The charging power, The rated power of the photovoltaic inverter is... The rated power of the energy storage converter. These are current-limited charging parameters. .

[0033] Thirdly, embodiments of the present invention provide an electronic device, comprising:

[0034] At least one processor;

[0035] At least one memory for storing at least one program;

[0036] When at least one of the programs is executed by at least one of the processors, the constrained control method for the photovoltaic-storage microgrid system as described in the second aspect is implemented.

[0037] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a processor-executable program, which, when executed by a processor, is used to implement the constraint control method for a photovoltaic-storage microgrid system as described in the second aspect.

[0038] The photovoltaic-storage microgrid system, its constraint control method, electronic equipment, and storage medium proposed in this invention not only integrate photovoltaic and energy storage into a stable photovoltaic-storage microgrid system, but also achieve stable photovoltaic power output by controlling the photovoltaic inverter to perform maximum power point tracking (MPPT). In particular, by monitoring the opening and closing status of the mains switching switch in real time to distinguish between grid-connected and off-grid scenarios, and based on this, the photovoltaic-storage microgrid system is constrained and controlled separately in grid-connected and off-grid scenarios in combination with the photovoltaic scenario and real-time load conditions, thereby achieving stable operation of the photovoltaic-storage microgrid system. Attached Figure Description

[0039] Figure 1 This is a schematic block diagram of a photovoltaic-storage microgrid system provided in an embodiment of the present invention;

[0040] Figure 2 This is a flowchart of a constraint control method for a photovoltaic-storage microgrid system provided in an embodiment of the present invention;

[0041] Figure 3 This is a flowchart following step S23, "charging the energy storage converter based on the first photovoltaic surplus power," provided in an embodiment of the present invention.

[0042] Figure 4 This is a flowchart of step S32 provided in an embodiment of the present invention;

[0043] Figure 5 yes Figure 4 The flowchart of step S322 in the document;

[0044] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] It should be noted that although functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart.

[0047] Figure 1 This is a schematic block diagram of a photovoltaic-storage microgrid system provided in an embodiment of the present invention.

[0048] like Figure 1 As shown, the photovoltaic-storage microgrid system may include, but is not limited to:

[0049] Energy storage converter 100, photovoltaic inverter 300, isolation transformer 500, battery unit 200, photovoltaic unit 400 and mains power transfer switch 600;

[0050] The battery unit 200 is connected to the mains power switch 600 via the energy storage converter 100. The photovoltaic unit 400 is connected to the mains power switch 600 via the photovoltaic inverter 300 and the isolation transformer 500. The AC port of the energy storage converter 100 is connected to the AC port of the photovoltaic inverter 300 via the isolation transformer 500. The mains power switch 600 is used to connect to the mains power input. A load port for powering the load is provided between the mains power switch 600 and the isolation transformer 500.

[0051] The energy storage converter 100 is used to convert the DC energy of the battery unit 200 into AC energy, which can realize bidirectional AC-DC energy conversion; the photovoltaic inverter 300 is used to convert the DC energy of the photovoltaic unit 400 into AC energy, which can realize unidirectional DC-to-AC energy transmission; the AC port of the energy storage converter 100 and the AC port of the photovoltaic inverter 300 are isolated by the isolation transformer 500 to prevent AC coupling from affecting each other. In other words, by configuring a photovoltaic and energy storage microgrid system that integrates photovoltaic and energy storage stability, it is possible to further effectively and reliably constrain and control the photovoltaic and energy storage microgrid system.

[0052] It is understood that the specific specifications and parameters of the energy storage converter 100, photovoltaic inverter 300, isolation transformer 500, battery unit 200, photovoltaic unit 400, and mains power transfer switch 600 can be, but are not limited to, set according to the actual application scenario. This part is well known to those skilled in the art and is not the main inventive point of this invention, so it will not be elaborated here. For example, the photovoltaic unit 400 can, but is not limited to, use common PV panels; the mains power transfer switch 600 can, but is not limited to, use an STS, i.e., a static transfer switch. As a grid-connected and off-grid transfer switch, it is mainly used for switching between two power sources. It is a common power source two-to-one automatic switching system. Under normal working conditions, when the main power source is within the normal voltage range, the load is always connected to the main power source. When the main power source fails, the load automatically switches to the backup power source. After the main power source returns to normal, the load automatically switches back to the main power source. Here, "main power source" refers to the mains power. In other words, when the mains power is normal, the STS is closed; conversely, when the mains power is abnormal, the STS is open.

[0053] The photovoltaic-storage microgrid system and application scenarios described in the embodiments of this invention are intended to more clearly illustrate the technical solutions of the embodiments of this invention, and do not constitute a limitation on the technical solutions provided by the embodiments of this invention. As the photovoltaic-storage microgrid system evolves and new application scenarios emerge, the technical solutions provided by the embodiments of this invention are also applicable to similar technical problems.

[0054] It will be understood by those skilled in the art that Figure 1 The photovoltaic-storage microgrid system shown in the figure does not constitute a limitation on the embodiments of the present invention. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0055] Figure 2 This is a flowchart illustrating a constraint control method for a photovoltaic-storage microgrid system according to an embodiment of the present invention. Figure 2 As shown, the constraint control method for the photovoltaic-storage microgrid system may include, but is not limited to, steps S1 to S3.

[0056] Step S1: Control the photovoltaic inverter to perform MPPT (Maximum Power Point Tracking) and monitor the opening and closing status of the mains power transfer switch in real time.

[0057] Step S2: If the mains power switching switch is in the closed state, generate a grid connection constraint control strategy for the photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power and the real-time mains electricity price; otherwise, proceed to step S3.

[0058] Among them, photovoltaic power is obtained by converting the DC energy input from the photovoltaic unit by the photovoltaic inverter, and load power is the power required for the load to operate as monitored through the load port;

[0059] Step S3: Based on the obtained relationship between photovoltaic power and load power, generate an off-grid constraint control strategy for photovoltaic-storage microgrid systems.

[0060] In this step, the photovoltaic inverter is controlled to perform maximum power point tracking (MPPT) to achieve stable photovoltaic power output. In particular, the opening and closing status of the mains power switching switch is monitored in real time to distinguish between grid-connected and off-grid scenarios. Based on this, the photovoltaic-storage microgrid system is constrained and controlled separately in grid-connected and off-grid scenarios, taking into account the photovoltaic scenario and real-time load conditions, so as to achieve stable operation of the photovoltaic-storage microgrid system.

[0061] In one embodiment of the present invention, step S2, which generates a grid-connected constraint control strategy for a photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power and the real-time grid electricity price, may include, but is not limited to, the following steps:

[0062] Step S21: When the photovoltaic power is greater than or equal to the load power and the grid electricity price is at its peak, control the energy storage converter to enter the standby state and provide separate power supply to the load based on the photovoltaic power, and use the first photovoltaic surplus power to connect to the grid, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power.

[0063] or,

[0064] Step S22: When the photovoltaic power is less than the load power and the grid electricity price is at its peak, control the energy storage converter to enter the discharge state to output discharge power, and provide mixed power supply to the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power.

[0065] or,

[0066] Step S23: When the photovoltaic power is greater than or equal to the load power and the grid electricity price is in a valley, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state, and the energy storage converter is charged based on the first photovoltaic surplus power.

[0067] or,

[0068] Step S24: When the photovoltaic power is less than the load power and the grid electricity price is in a low-price period, control the energy storage converter to enter the standby state and provide separate power supply to the load based on the grid electricity.

[0069] In this step, when the photovoltaic power is greater than or equal to the load power and the grid electricity price is at its peak, it means that the photovoltaic power is sufficient to provide the load power. The load can be supplied with power separately based on the photovoltaic power. At the same time, there is still a certain amount of photovoltaic power in reserve. Since the grid electricity price is at its peak, it is not suitable to connect to the grid through the grid. Instead, the first photovoltaic surplus power is used to connect to the grid, thereby realizing the grid connection constraint control of the photovoltaic-storage microgrid system.

[0070] When the photovoltaic power is less than the load power and the grid electricity price is at its peak, it means that the photovoltaic power is insufficient to fully provide the load power and can only provide a portion of the power. At the same time, since the grid electricity price is at its peak, it is not suitable to connect to the grid through the grid. Instead, the energy storage converter is controlled to enter the discharge state to output discharge power. The discharge power is used to supplement the load power that the photovoltaic cannot provide. That is, the load is supplied with a hybrid power supply based on photovoltaic power and discharge power, thereby realizing the grid connection constraint control of the photovoltaic-storage microgrid system.

[0071] When the photovoltaic power is greater than or equal to the load power and the grid electricity price is in a trough, it means that the photovoltaic power is sufficient to provide the load power. The load can be supplied with power separately based on the photovoltaic power. At the same time, the surplus photovoltaic power can be used to charge the energy storage converter, thereby realizing the grid connection constraint control of the photovoltaic-storage microgrid system.

[0072] When the photovoltaic power is less than the load power and the grid electricity price is at its lowest point, it indicates that the photovoltaic power is insufficient to fully supply the load power. Since the grid electricity price is at its lowest point, it is recommended to supply power through the grid electricity, while storing both the photovoltaic power and the energy storage power for backup. This means controlling the energy storage converter to enter standby mode and supplying power to the load separately based on the grid electricity, thereby achieving grid-connected constraint control of the photovoltaic-storage microgrid system.

[0073] It can be seen that, under grid-connected conditions, by comparing the relative magnitudes of photovoltaic power and load power and combining them with the peak and off-peak conditions of the grid electricity price, grid-connected constraint control of the photovoltaic-storage microgrid system under corresponding conditions can be effectively and reliably implemented, thereby facilitating the stable operation of the photovoltaic-storage microgrid system.

[0074] like Figure 3As shown, in one embodiment of the present invention, when the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S23, after charging the energy storage converter based on the first photovoltaic surplus power, may further include, but is not limited to, the following steps:

[0075] Step S231: Control the energy storage converter to enter standby mode and use the second photovoltaic surplus power to connect to the grid, wherein the second photovoltaic surplus power is the difference between the first photovoltaic surplus power and the charging power.

[0076] In other words, if the surplus power of the first photovoltaic power is greater than the charging power required by the energy storage converter, then there is still surplus power of the first photovoltaic power. Therefore, there is no need to use the battery power stored in the energy storage converter, but to directly use this surplus power of the second photovoltaic power to connect to the grid, thereby realizing the grid connection constraint control of the photovoltaic-storage microgrid system.

[0077] In one embodiment of the present invention, step S3 may include, but is not limited to, the following steps:

[0078] Step S31: When the photovoltaic power is less than the load power, control the energy storage converter to enter the discharge state to output discharge power, and provide mixed power supply to the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power.

[0079] or,

[0080] Step S32: When the photovoltaic power is greater than or equal to the load power, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state. The energy storage converter is charged based on the first photovoltaic surplus power, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power.

[0081] In this step, when the photovoltaic power is less than the load power and is not connected to the grid, it means that the photovoltaic power is insufficient to fully provide the load power and can only provide a portion of the power. It is necessary to control the energy storage converter to enter the discharge state to output discharge power. The discharge power is used to supplement the load power that the photovoltaic cannot provide. That is, the load is supplied with a mixed power supply based on the photovoltaic power and the discharge power, thereby realizing the off-grid constraint control of the photovoltaic-storage microgrid system. When the photovoltaic power is greater than or equal to the load power and is not connected to the grid, it means that the photovoltaic power is sufficient to provide the load power. The load can be supplied with power separately based on the photovoltaic power. At the same time, the energy storage converter is controlled to enter the charging state. The surplus photovoltaic power can be used to charge the energy storage converter, thereby realizing the grid-connected constraint control of the photovoltaic-storage microgrid system.

[0082] like Figure 4 As shown in one embodiment of the present invention, when the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S32 may further include, but is not limited to, the following steps:

[0083] Step S321: Obtain the AC bus voltage of the energy storage converter through the AC port of the energy storage converter;

[0084] Step S322: Based on the relationship between the AC bus voltage and the predetermined AC bus rated voltage and AC bus threshold voltage, the power output of the photovoltaic inverter is controlled, wherein the AC bus threshold voltage is greater than the AC bus rated voltage.

[0085] In this step, considering that the surplus photovoltaic power is greater than the charging power required by the energy storage inverter, that is, when the battery cell is fully charged or the energy storage inverter is current-limited charging, there is excess photovoltaic energy, which may lead to an increase in AC bus voltage or even system collapse. By obtaining the AC bus voltage of the energy storage inverter under real-time conditions, and then based on the relationship between the AC bus voltage and the predetermined AC bus rated voltage and AC bus threshold voltage, the power output of the photovoltaic inverter is controlled to avoid abnormal increase in AC bus voltage.

[0086] It should be noted that the rated voltage of the AC bus represents the rated normal operating condition of the AC bus, while the threshold voltage of the AC bus represents the critical normal operating condition of the AC bus. Therefore, generally speaking, the reasonable AC bus voltage should not exceed the AC bus threshold voltage. In actual scenarios, the rated voltage of different AC buses may be different, and the AC bus threshold voltage will change accordingly. For example, the AC bus threshold voltage in a certain scenario is 1.1 times the rated voltage of the AC bus.

[0087] like Figure 5 As shown, in one embodiment of the present invention, step S322 may include, but is not limited to, the following steps:

[0088] Step S3221: When the AC bus voltage is less than or equal to the AC bus rated voltage, control the photovoltaic inverter to output the rated power of the photovoltaic inverter; or, when the AC bus voltage is greater than or equal to the AC bus threshold voltage, control the photovoltaic inverter not to output power; or, when the AC bus voltage is greater than the AC bus rated voltage and less than the AC bus threshold voltage, control the photovoltaic inverter to output variable power, wherein the variable power decreases linearly over time from the rated power of the photovoltaic inverter to zero.

[0089] In this step, when the AC bus voltage is less than or equal to the AC bus rated voltage, it indicates that the AC bus voltage is within the normal range. Therefore, there is no need to excessively limit the output power of the photovoltaic inverter. Instead, the photovoltaic inverter is controlled to output its rated power to ensure that the AC bus voltage remains within the normal range. When the AC bus voltage is greater than or equal to the AC bus threshold voltage, it indicates that the AC bus voltage is already outside the acceptable range. In this case, the photovoltaic inverter needs to be restricted from outputting power to prevent the AC bus voltage from rising abnormally again. When the AC bus voltage is greater than the AC bus rated voltage but less than the AC bus threshold voltage, it indicates that the AC bus voltage is within the critical range, meaning that a limited amount of photovoltaic energy can be output. Therefore, the photovoltaic inverter's output power is controlled to vary. Since this varied power decreases linearly over time from the photovoltaic inverter's rated power to zero, it can provide photovoltaic energy to the energy storage converter within certain limits, while effectively preventing abnormal rises in the AC bus voltage. The "time" here can be set according to the actual scenario, such as a custom unit time or a fixed time period, and is not limited here.

[0090] In one embodiment of the present invention, when the energy storage converter adopts a current-limiting charging method, step S32 further includes the following steps:

[0091] Step S323: Based on the charging power and the rated power of the photovoltaic inverter, control the energy storage converter to maintain the AC bus voltage at... ,in, The expression is as follows:

[0092] ;

[0093] The rated voltage of the AC bus. The AC bus threshold voltage, For charging power, This refers to the rated power of the photovoltaic inverter. This refers to the rated power of the energy storage converter. These are current-limited charging parameters. .

[0094] It can be seen that when This indicates that the charging power of the energy storage converter under current limiting conditions has exceeded the rated power of the photovoltaic inverter. Therefore, even if there is excess photovoltaic energy, it is not easy to cause an abnormal rise in the AC bus voltage. Thus, the AC bus voltage can be maintained at the rated AC bus voltage. Conversely, this indicates that excess photovoltaic energy may cause an abnormal rise in the AC bus voltage. Therefore, it is necessary to further limit the AC bus voltage of the energy storage converter to be lower to prevent an abnormal rise in the AC bus voltage.

[0095] Understandably, The settings can be adjusted according to the actual scenario; there are no restrictions here. Then the above formula can be simplified to:

[0096] .

[0097] Figure 6 This is a schematic diagram of the structure of an electronic device 1000 provided in an embodiment of the present invention. For example... Figure 6 As shown, the electronic device 1000 includes a memory 1100 and a processor 1200. The number of memories 1100 and processors 1200 can be one or more. Figure 6 Taking a memory 1100 and a processor 1200 as an example; the memory 1100 and the processor 1200 in the device can be connected via a bus or other means. Figure 6 Taking the example of a connection between China and Israel via a bus.

[0098] The memory 1100, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the constraint control method of the photovoltaic-storage microgrid system provided in any embodiment of the present invention. The processor 1200 implements the aforementioned constraint control method of the photovoltaic-storage microgrid system by running the software programs, instructions, and modules stored in the memory 1100.

[0099] The memory 1100 may primarily include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function. Furthermore, the memory 1100 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the memory 1100 may further include memory remotely located relative to the processor 1200, and these remote memories can be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0100] An embodiment of the present invention also provides a computer-readable storage medium storing computer-executable instructions for executing a constraint control method for a photovoltaic-storage microgrid system as provided in any embodiment of the present invention.

[0101] An embodiment of the present invention also provides a computer program product, including a computer program or computer instructions, which are stored in a computer-readable storage medium. A processor of a computer device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the computer device to perform the constraint control method for a photovoltaic-storage microgrid system as provided in any embodiment of the present invention.

[0102] The electronic devices and application scenarios described in the embodiments of this invention are for the purpose of more clearly illustrating the technical solutions of the embodiments of this invention, and do not constitute a limitation on the technical solutions provided by the embodiments of this invention. As those skilled in the art will know, with the evolution of electronic devices and the emergence of new application scenarios, the technical solutions provided by the embodiments of this invention are also applicable to similar technical problems.

[0103] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0104] In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor (such as a central processing unit, digital signal processor, or microprocessor), or as hardware, or as integrated circuits, such as application-specific integrated circuits (ASICs). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0105] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process or execution thread, and components may be located on a single computer or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, or a network, such as the Internet interacting with other systems via signals).

Claims

1. A constraint control method for a photovoltaic-storage microgrid system, characterized in that, The photovoltaic-storage microgrid system includes an energy storage converter, a photovoltaic inverter, an isolation transformer, battery units, photovoltaic units, and a mains power transfer switch. The battery units are connected to the mains power transfer switch via the energy storage converter. The photovoltaic units are connected to the mains power transfer switch sequentially via the photovoltaic inverter and the isolation transformer. The AC port of the energy storage converter is connected to the AC port of the photovoltaic inverter via the isolation transformer. The mains power transfer switch is used to connect to the mains power input. A load port for powering the load is provided between the mains power transfer switch and the isolation transformer. The method includes the following steps: Step S1: Control the photovoltaic inverter to perform maximum power point tracking (MPPT) and monitor the opening and closing status of the mains power switching switch in real time. Step S2: If the mains power switching switch is in the closed state, generate a grid-connected constraint control strategy for the photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power and the real-time mains electricity price; otherwise, proceed to step S3. The photovoltaic power is obtained by converting the DC energy input to the photovoltaic unit by the photovoltaic inverter, and the load power is the power required for the load to operate as monitored through the load port. Step S3: Based on the obtained relationship between photovoltaic power and load power, generate an off-grid constraint control strategy for the photovoltaic-storage microgrid system; Step S3 includes the following steps: Step S31: When the photovoltaic power is less than the load power, control the energy storage converter to enter the discharge state to output discharge power, and perform mixed power supply for the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power; or, Step S32: When the photovoltaic power is greater than or equal to the load power, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state. The energy storage converter is charged based on the first photovoltaic surplus power, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power. When the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S32 further includes the following steps: Step S321: Obtain the AC bus voltage of the energy storage converter through the AC port of the energy storage converter; Step S322: Based on the relationship between the AC bus voltage and the predetermined AC bus rated voltage and AC bus threshold voltage, the photovoltaic inverter is controlled for power output, wherein the AC bus threshold voltage is greater than the AC bus rated voltage. When the energy storage converter adopts a current-limited charging method, step S32 further includes the following steps: Step S323: Based on the charging power and the rated power of the photovoltaic inverter, control the energy storage converter to maintain the AC bus voltage at V, where the expression for V is as follows: V n The rated voltage of the AC bus is V. x The AC bus threshold voltage, kP n1 For the charging power, P n P is the rated power of the photovoltaic inverter. n1 The rated power of the energy storage converter is given by k, where k is the current-limiting charging parameter and 0 is the rated power of the energy storage converter. <k<1。 2. The constraint control method for a photovoltaic-storage microgrid system according to claim 1, characterized in that, Step S2 involves generating a grid-connected constraint control strategy for the photovoltaic-storage microgrid system based on the obtained relationship between photovoltaic power and load power, combined with the real-time grid electricity price. This strategy includes the following steps: Step S21: When the photovoltaic power is greater than or equal to the load power and the mains electricity price is at its peak, control the energy storage converter to enter standby mode and supply power to the load separately based on the photovoltaic power, and connect to the grid with the first photovoltaic surplus power, wherein the first photovoltaic surplus power is the difference between the photovoltaic power and the load power; or, Step S22: When the photovoltaic power is less than the load power and the mains electricity price is at its peak, control the energy storage converter to enter the discharge state to output discharge power, and perform mixed power supply for the load based on the photovoltaic power and the discharge power, wherein the discharge power is the difference between the load power and the photovoltaic power; or, Step S23: When the photovoltaic power is greater than or equal to the load power and the mains electricity price is in a valley, the load is supplied with power separately based on the photovoltaic power, and the energy storage converter is controlled to enter the charging state, and the energy storage converter is charged based on the first photovoltaic surplus power. or, Step S24: When the photovoltaic power is less than the load power and the mains electricity price is in a low-price period, control the energy storage converter to enter standby mode and provide separate power supply to the load based on the mains electricity.

3. The constraint control method for a photovoltaic-storage microgrid system according to claim 2, characterized in that, When the first photovoltaic surplus power is greater than the charging power required by the energy storage converter, step S23, after charging the energy storage converter based on the first photovoltaic surplus power, further includes the following steps: Step S231: Control the energy storage converter to enter standby mode and connect to the grid using the second photovoltaic surplus power, wherein the second photovoltaic surplus power is the difference between the first photovoltaic surplus power and the charging power.

4. The constraint control method for a photovoltaic-storage microgrid system according to claim 1, characterized in that, Step S322 includes the following steps: Step S3221: When the AC bus voltage is less than or equal to the AC bus rated voltage, control the photovoltaic inverter to output the rated power of the photovoltaic inverter; or, when the AC bus voltage is greater than or equal to the AC bus threshold voltage, control the photovoltaic inverter not to output power; or, when the AC bus voltage is greater than the AC bus rated voltage and less than the AC bus threshold voltage, control the photovoltaic inverter to output variable power, wherein the variable power decreases linearly over time from the rated power of the photovoltaic inverter to zero.

5. An electronic device, characterized in that, include: At least one processor; At least one memory for storing at least one program; When at least one of the programs is executed by at least one of the processors, the constraint control method for the photovoltaic-storage microgrid system as described in any one of claims 1 to 4 is implemented.

6. A computer-readable storage medium, characterized in that, It stores a processor-executable program, which, when executed by the processor, is used to implement the constraint control method for the photovoltaic-storage microgrid system as described in any one of claims 1 to 4.

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