Photovoltaic power supply control method and photovoltaic system

Abstract

The invention relates to the technical field of photovoltaic power supply, in particular to a photovoltaic power supply control method and a photovoltaic system. The photovoltaic power supply control method is applied to a photovoltaic system, and comprises the following steps: detecting whether the connection between a mains supply network and an AC port is disconnected; if yes, detecting whether the connection between the second inverter assembly and the AC port is disconnected; if yes, collecting the grid-connected maximum output power of the micro grid-connected inverter, the maximum photovoltaic output power of the first photovoltaic panel, the load power of the load and the battery maximum charging power of the energy storage battery; whether the first sum of the load power and the maximum charging power of the battery is larger than the second sum of the maximum output power and the maximum photovoltaic output power or not is judged; and if yes, conducting connection between the second inverter assembly and the alternating current port. The photovoltaic energy utilization rate can be maximized.

Description

A photovoltaic power supply control method and photovoltaic system Technical Field

[0001] This invention relates to the field of photovoltaic power supply technology, and in particular to a photovoltaic power supply control method and a photovoltaic system. Background Technology

[0002] With the popularization of photovoltaic energy, many photovoltaic systems are being upgraded with micro grid-connected inverters, and excess electricity can be fed into the grid, meeting the basic photovoltaic power generation needs of users.

[0003] However, with the upgrading of users' electricity demand, traditional grid-connected photovoltaic systems rely on the mains power grid for support. Once the mains power fails, the micro grid-connected inverter will stop working due to its own mandatory "island protection" function (automatically shutting down after detecting grid voltage loss to avoid forming an island operation that threatens grid security). This results in the photovoltaic energy not being able to continue to be used, users losing power supply, and the backup power demand being difficult to meet. Summary of the Invention

[0004] This invention provides a photovoltaic power supply control method and a photovoltaic system to solve the problem of insufficient utilization of photovoltaic energy.

[0005] This invention discloses a photovoltaic power supply control method applied to a photovoltaic system. The photovoltaic system includes: an AC port; a first inverter assembly and a second inverter assembly connected in parallel through the AC port. The first inverter assembly includes an energy storage inverter, a first photovoltaic panel and an energy storage battery connected to the energy storage inverter, and the second inverter assembly includes a micro grid-connected inverter and a second photovoltaic panel connected to the micro grid-connected inverter; a mains power network connected to the AC port; and a load connected to the AC port. The photovoltaic power supply control method includes the following steps: detecting whether the connection between the mains power network and the AC port is disconnected; if so, detecting whether the connection between the second inverter assembly and the AC port is disconnected; if so, collecting the maximum grid-connected output power of the micro grid-connected inverter, the maximum photovoltaic output power of the first photovoltaic panel, the load power of the load, and the maximum battery charging power of the energy storage battery, and determining whether a first sum of the load power and the maximum battery charging power is greater than a second sum of the maximum output power and the maximum photovoltaic output power; if so, connecting the second inverter assembly and the AC port.

[0006] Optionally, the step of closing the connection between the second inverter component and the AC port includes: waiting for a preset time before performing the step of closing the connection between the second inverter component and the AC port.

[0007] Optionally, the preset duration is 1 minute.

[0008] Optionally, after the step of detecting whether the connection between the second inverter component and the AC port is disconnected, the method includes: if not, determining whether the first sum of the load power and the maximum battery charging power is less than the maximum grid-connected output power; if yes, disconnecting the connection between the micro grid-connected inverter and the AC port.

[0009] Optionally, the step of detecting whether the connection between the mains power network and the AC port is disconnected includes: if not, detecting whether the mains power network is in a normal state; if not, disconnecting the connection between the mains power network and the AC port.

[0010] Optionally, after the step of detecting whether the mains power network is in a normal state, the method includes: if so, determining whether the first summation is greater than the second summation; if so, driving the first photovoltaic panel, the micro grid-connected inverter, and the mains power network to supply power to the load and the energy storage battery.

[0011] Optionally, after determining whether the first summation is greater than the second summation, the method includes: if not, driving the first photovoltaic panel and the micro grid-connected inverter to supply power to the load, the energy storage battery, and the mains power network.

[0012] Optionally, after the step of disconnecting the mains power network from the AC port, the process includes: driving the first photovoltaic panel and the micro grid-connected inverter to supply power to the load and the energy storage battery.

[0013] The present invention also discloses a photovoltaic system, the photovoltaic system comprising: an AC port; at least one set of first inverter components and at least one set of second inverter components connected in parallel through the AC port, the first inverter components comprising an energy storage inverter, and a first photovoltaic panel and an energy storage battery connected to the energy storage inverter, the second inverter components comprising a micro grid-connected inverter, and a second photovoltaic panel connected to the micro grid-connected inverter; a mains power network connected to the AC port; and a load connected to the AC port; the photovoltaic system is used to perform the method described in any one of claims 1-7.

[0014] Optionally, the mains power network is connected to the AC port via a first relay; the load is connected to the AC port via a second relay; and the miniature grid-connected inverter is connected to the AC port via a third relay.

[0015] The beneficial effects of the photovoltaic power supply control method and photovoltaic system provided in this embodiment of the invention are as follows: when the connection between the mains power grid and the AC port is disconnected, it is determined whether the maximum output power of the combination of the first inverter component and the second inverter component is within the maximum absorbable power range of the photovoltaic system. If so, the second inverter component is connected to the photovoltaic system, that is, the micro grid-connected inverter is connected to the AC port, making full use of the photovoltaic energy of the second inverter component, and combining the electrical energy of the first inverter component and the second inverter component to supply power to the load, thereby maximizing the photovoltaic energy utilization rate. Attached Figure Description

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the drawings: Figure 1 is a flowchart of an embodiment of the photovoltaic power supply control method provided by the present invention; Figure 2 is a structural schematic diagram of an embodiment of the photovoltaic system provided by the present invention; Figure 3 is a schematic diagram of the power supply flow of the photovoltaic system provided by the present invention when S1 is open and S3 is closed; Figure 4 is a flowchart of a second embodiment of the photovoltaic power supply control method provided by the present invention; Figure 5 is a schematic diagram of the power supply flow of the photovoltaic system provided by the present invention when S1 is open and S3 is open; Figure 6 is a flowchart of a third embodiment of the photovoltaic power supply control method provided by the present invention; Figure 7 is a schematic diagram of the power supply flow when the first sum is greater than the second sum; Figure 8 is a schematic diagram of the power supply flow when the first sum is less than or equal to the second sum.

[0017] The figures are labeled as follows: 10, photovoltaic system; 11, AC port; 12, first inverter assembly; 121, energy storage inverter; 122, first photovoltaic panel; 123, energy storage battery; 13, second inverter assembly; 131, micro grid-connected inverter; 132, second photovoltaic panel; 14, mains power network; 15, load; S1, first relay; S2, second relay; S3, third relay. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] Please refer to Figures 1 and 2. Figure 1 is a flowchart of an embodiment of the photovoltaic power supply control method provided by the present invention, and Figure 2 is a structural diagram of an embodiment of the photovoltaic system provided by the present invention.

[0020] The photovoltaic system 10 includes an AC port 11. In the entire photovoltaic system 10, the AC port 11 is the core hub for power collection and distribution. On the one hand, it integrates AC power from multiple sources (output of energy storage inverter 121, output of micro grid-connected inverter 131, and mains network 14), and on the other hand, it distributes the integrated power to the load 15 for power supply and to the energy storage battery 123 for charging.

[0021] The first inverter assembly 12 and the second inverter assembly 13 are connected in parallel via AC port 11. The first inverter assembly 12 includes an energy storage inverter 121, a first photovoltaic panel 122, and an energy storage battery 123. The first photovoltaic panel 122 and the energy storage battery 123 are both directly connected to the energy storage inverter 121, and the AC output terminal of the energy storage inverter 121 is connected to AC port 11. The second inverter assembly 13 includes a micro grid-connected inverter 131 and a second photovoltaic panel 132. The second photovoltaic panel 132 is connected to the DC input terminal of the micro grid-connected inverter 131, and the AC output terminal of the micro grid-connected inverter 131 is connected to AC port 11.

[0022] The mains power network 14 is controllably connected to the AC port 11 via the first relay S1 to enable or disable mains power. The load 15 is controllably connected to the AC port 11 via the second relay S2 to obtain system power. The third relay S3 is connected in series between the micro grid-connected inverter 131 and the AC port 11 to controllably switch the power connection between the micro grid-connected inverter 131 and the AC port 11. The on and off states of the first relay S1, the second relay S2, and the third relay S3 can be flexibly controlled, thereby enabling dynamic switching and coordination of power sources under different operating scenarios, and accurately matching various operating conditions such as mains power / mains power failure, sufficient / insufficient / overflowing photovoltaic power.

[0023] In the scenario shown in Figure 2, assume that the maximum photovoltaic output power of the first photovoltaic panel 122 is... The maximum grid-connected output power of the micro grid-connected inverter 131 is The load power of load 15 is The maximum charging power of energy storage battery 123 is .

[0024] The photovoltaic power supply control method provided by the present invention includes the following steps: S101: Detect whether the connection between the mains network and the AC port is disconnected; if so, proceed to step S102.

[0025] In a specific implementation scenario, the on / off state of the first relay S1 is collected, or the grid voltage / frequency signal on the side of the mains network 14 corresponding to the AC port 11 is directly detected to detect whether the connection between the mains network 14 and the AC port 11 is disconnected.

[0026] If the first relay S1 remains closed after the mains power grid 14 fails, the photovoltaic system 10 will form an independent power supply island (a closed-loop power supply network consisting of load 15, photovoltaic, and energy storage). This island can cause grid maintenance personnel to accidentally touch the live island lines when repairing the de-energized lines, leading to electric shock accidents. At the same time, the voltage and frequency of the island operation are not controlled by the grid and may not match the parameters (voltage phase and frequency) when the grid restores power. The moment the grid is restored, a huge current surge will be generated, damaging system equipment and grid facilities.

[0027] A grid voltage / frequency detection module can be built into the energy storage inverter 121 to monitor the power supply status of the mains network 14 in real time. Normal mains power has a stable voltage and frequency range, such as 220V±10% and 50Hz±0.5Hz. The detected power supply status is compared with the stable state to determine if the mains network 14 has lost power. When the mains power fails, the grid voltage / frequency detection module detects a sudden voltage drop to 0 or a frequency exceeding the normal range, and the photovoltaic system 10 immediately drives the first relay S1 to disconnect. The first relay S1 can be an electromagnetic or solid-state relay, capable of quickly disconnecting in response to system commands, completely isolating the mains network 14 from the AC port 11.

[0028] S102: Detect whether the connection between the second inverter component and the AC port is disconnected; if so, proceed to step S103.

[0029] In a specific implementation scenario, the first relay S1 is disconnected, thus the connection between the mains power network 14 and the AC port 11 is broken, and the photovoltaic system 10 enters off-grid mode. Further detection is needed to determine whether the connection between the second inverter component 13 and the AC port 11 is broken. The connection status between the mains power network 14 and the AC port 11 can be determined by detecting the on / off state of the third relay S3.

[0030] If a disconnection is detected (the third relay S3 is not closed, and the micro grid-connected inverter 131 is not connected), then it is necessary to determine whether to switch the micro grid-connected inverter 131 through power judgment.

[0031] S103: Collect the maximum grid-connected output power of the micro grid-connected inverter, the maximum photovoltaic output power of the photovoltaic panel, the load power of the load, and the maximum charging power of the energy storage battery. Determine whether the first sum of the load power and the maximum charging power of the battery is greater than the second sum of the maximum output power and the maximum photovoltaic output power. If so, proceed to step S104.

[0032] In a specific implementation scenario, the third relay S3 is turned off, the connection between the second inverter component 13 and the AC port 11 is disconnected, and the maximum grid-connected output power of the micro grid-connected inverter 131 is collected. The maximum photovoltaic output power of the first photovoltaic panel 122 Load 15 power The maximum charging power of the energy storage battery 123 .

[0033] 15 power load +Maximum battery charging power Calculate the first sum, which represents the maximum absorbable power of the photovoltaic system 10 under off-grid conditions (the total power required by load 15 + the maximum charging power of the battery). Maximum grid-connected output power. +Maximum photovoltaic output power Calculate the second sum, which represents the maximum output power when the first inverter component 12 and the second inverter component 13 are combined (the peak total power of the photovoltaic on the 1 side of the energy storage inverter 121 + the photovoltaic on the 1 side of the micro grid-connected inverter 131).

[0034] By comparing the magnitudes of the first summation and the second summation, it is determined whether the maximum output power of the combination of the first inverter component 12 and the second inverter component 13 is within the maximum absorbable power range of the photovoltaic system 10, so as to avoid power overflow after connecting the micro grid-connected inverter 131, which would cause the photovoltaic system 10 to be overloaded.

[0035] If the second summation is greater than or equal to the first summation, it indicates that the maximum output power of the combination of the first inverter component 12 and the second inverter component 13 has exceeded the maximum absorption capacity of the photovoltaic system 10. After connecting the micro grid-connected inverter 131, power overflow will occur, which may lead to abnormal voltage / frequency of the photovoltaic system 10 and equipment overload damage. Therefore, the third relay S3 is kept in the open state to disconnect the connection between the micro grid-connected inverter 131 and the AC port 11, and only the first inverter component 12 is allowed to supply power to the photovoltaic system 10 to ensure the safe and stable operation of the system.

[0036] If the first sum is greater than the second sum, it means that the maximum output power of the combination of the first inverter component 12 and the second inverter component 13 is within the maximum absorption range of the photovoltaic system 10. After connecting the micro grid-connected inverter 131, there will be no power overflow and the photovoltaic energy of the second inverter component 13 can be fully utilized. Therefore, the operation of closing the third relay S3 is executed to connect the micro grid-connected inverter 131 to the AC port 11, so as to realize the coordinated power supply of the first inverter component 12 and the second inverter component 13 and maximize the photovoltaic energy utilization rate.

[0037] S104: Connect the second inverter assembly and the AC port.

[0038] In a specific implementation scenario, the first summation is greater than the second summation. Therefore, the connection between the second inverter component 13 and the AC port 11 is established, and the photovoltaic energy of the micro grid-connected inverter 131 is safely connected. This allows the first inverter component 12 and the second inverter component 13 to work together to supply power to the load 15 and charge the energy storage battery 123, maximizing the utilization of photovoltaic resources while avoiding system overload.

[0039] In this case, please refer to Figure 3, which is a schematic diagram of the power supply flow of the photovoltaic system provided by the present invention when S1 is open and S3 is closed. The first photovoltaic panel 122 converts solar energy into direct current (DC), inputs it into the energy storage inverter, and outputs it to the AC port 11 after being inverted into alternating current (AC). The second photovoltaic panel 132 converts solar energy into DC, inputs it into the micro grid-connected inverter, and outputs it to the AC port 11 after being inverted into AC. After integrating all the AC power, the AC port 11 delivers it to the load through the closed second relay S2 to meet the load's power demand. Since the total photovoltaic power provided by the combination of the first photovoltaic panel 122 and the second photovoltaic panel 132 is sufficient (exceeding the load demand), as shown in Figure 3, the excess power is input in reverse through the AC port to the energy storage inverter, converted into DC, and then used to charge the energy storage battery 123 until the energy storage battery 123 reaches a fully charged state.

[0040] When off-grid, the photovoltaic system 10 is not powered by the mains grid 14. The photovoltaic power of the first inverter component 12 and the second inverter component 13 fluctuates dynamically with changes in sunlight conditions. This may result in frequent switching situations where the third relay S3 is closed just when the conditions are met, only to be disconnected again when the sunlight intensifies and power overflows. Repeated switching will accelerate the wear and tear on the third relay S3, the micro grid-connected inverter 131, and the energy storage inverter 121, reducing the equipment lifespan. Therefore, a preset time is waited before the step of closing the connection between the second inverter component 13 and the AC port 11 is executed.

[0041] After a mains power outage, the energy storage inverter 121 needs to switch from grid-connected to off-grid mode (to maintain stable AC port voltage / frequency). This process typically takes 10-30ms. However, subsequent stabilization of bus parameters (to avoid fluctuations) requires a buffer period. Therefore, the preset duration is no less than 1 minute to ensure complete stability of the bus voltage and frequency, preventing instantaneous impacts when connecting the micro grid-connected inverter 131. Furthermore, changes in sunlight may rapidly decrease within minutes (e.g., cloud cover), reducing the power output of the micro grid-connected inverter 131. Excessive delay could prevent timely connection and miss opportunities for photovoltaic utilization. Therefore, the preset duration is set to 1 minute.

[0042] As described above, in this embodiment, when the connection between the mains power network and the AC port is disconnected, it is determined whether the maximum output power of the combination of the first inverter component and the second inverter component is within the maximum absorbable power range of the photovoltaic system. If so, the second inverter component is connected to the photovoltaic system, that is, the micro grid-connected inverter is connected to the AC port, making full use of the photovoltaic energy of the second inverter component, and combining the electrical energy of the first inverter component and the second inverter component to supply power to the load, thereby maximizing the photovoltaic energy utilization rate.

[0043] Please refer to Figure 4, which is a flowchart illustrating the second embodiment of the photovoltaic power supply control method provided by the present invention. The photovoltaic power supply control method provided by the present invention includes the following steps: S201: Detect whether the connection between the mains network and the AC port is disconnected; if so, proceed to step S202.

[0044] S202: Detect whether the connection between the second inverter component and the AC port is disconnected; if not, proceed to step S203.

[0045] In a specific implementation scenario, steps S201-S202 are basically the same as steps S101-S102 in the first embodiment of the photovoltaic power supply control method provided by the present invention, and will not be described again here.

[0046] S203: Determine whether the first sum of the load power and the battery's maximum charging power is less than the maximum output power. If so, proceed to step S204.

[0047] In a specific implementation scenario, the second inverter component 13 and the AC port 11 are connected. The second inverter component 13 is connected to the photovoltaic system 10. Since the first inverter component 12 and the second inverter component 13 are powered together in the system, it is necessary to determine whether there is a risk of overload caused by power removal.

[0048] Load power +Maximum battery charging power Calculate the first sum, which represents the maximum absorbable power of the photovoltaic system 10 under off-grid conditions (the total power required by load 15 + the maximum charging power of the battery). Determine whether the first sum is less than the maximum grid-connected output power of the micro grid-connected inverter 131, that is, determine whether the maximum output power of the micro grid-connected inverter 131 exceeds the maximum absorbable capacity of the photovoltaic system 10.

[0049] If so, disconnect the third relay S3 to cut off the power connection between the miniature grid-connected inverter 131 and the AC port 11.

[0050] S204: Keep the connection between the micro grid-connected inverter and the AC port disconnected.

[0051] In a specific implementation scenario, when the maximum output power of the micro grid-connected inverter 131 exceeds the maximum absorption capacity of the photovoltaic system 10, the connection between the micro grid-connected inverter 131 and the AC port 11 is promptly disconnected to avoid overload impact. Only the first inverter component 12 is retained to supply power to the photovoltaic system 10, ensuring the voltage and frequency stability of the photovoltaic system 10 in the off-grid state and protecting core equipment such as the energy storage battery 123, the load 15, and the energy storage inverter 121.

[0052] In other implementation scenarios, after the third relay S3 is disconnected, the maximum absorbable power (load power) of the photovoltaic system 10 is continuously monitored. +Maximum battery charging power ), and the maximum grid-connected output power and maximum photovoltaic output power When the maximum output power of the grid is +Maximum photovoltaic output power Load power +Maximum battery charging power At this time, the third relay S3 is closed, so that the second inverter component 13 can be reconnected to the photovoltaic system 10 to make full use of photovoltaic power.

[0053] Please refer to Figure 5, which is a schematic diagram of the power supply flow of the photovoltaic system provided by the present invention when S1 and S3 are disconnected. The first photovoltaic panel 122 converts solar energy into direct current, inputs it into the energy storage inverter, and outputs it to the AC port 11 after being inverted into alternating current.

[0054] The AC Port receives electrical energy and delivers it to the load through the closed second relay S2 to meet the load's power demand. If the total photovoltaic power provided by the first photovoltaic panel 122 is sufficient (exceeding the load demand), as shown in Figure 5, the excess electrical energy is input in reverse to the energy storage inverter 121 through the AC Port 11, converted into DC power, and then used to charge the energy storage battery 123 until the energy storage battery 123 reaches a fully charged state.

[0055] As described above, in this embodiment, when the mains power fails and the photovoltaic system is in an off-grid operation state, if the second inverter component is connected to the photovoltaic system, a power compatibility judgment is performed on the connected micro grid-connected inverter. When the sum of the load power and the maximum charging power of the battery is less than the maximum output power of the micro grid-connected inverter, the connection between the micro grid-connected inverter and the AC port is disconnected in time. This can prevent excessive power from causing abnormal fluctuations in the voltage and frequency of the AC port, effectively protecting the energy storage inverter, energy storage battery and load equipment from overload impact. At the same time, it ensures that the photovoltaic system retains only the stable power supply of the first inverter group, ensuring the continuity of core power demand.

[0056] Please refer to Figure 6, which is a flowchart illustrating the third embodiment of the photovoltaic power supply control method provided by the present invention. The photovoltaic power supply control method provided by the present invention includes the following steps: S301: Detect whether the connection between the mains network and the AC port is disconnected; if not, proceed to step S302.

[0057] In a specific implementation scenario, the on / off state of the first relay S1, or the mains power access signal of the AC port 11, is detected to check whether the connection between the mains power network 14 and the AC port 11 is disconnected. If the mains power network 14 and the AC port 11 are in a connected state, there is a risk that abnormal mains power will affect the system, and further detection is required.

[0058] S302: Check if the mains power network is in normal condition. If not, proceed to step S303. If yes, proceed to step S309.

[0059] In a specific implementation scenario, the core electrical parameters of the mains power network 14 are checked to see if they are within the preset standard range, including voltage (e.g., 220V±10%), frequency (e.g., 50Hz±0.5Hz), phase stability, and whether there are faults such as voltage surge / dip or excessive harmonics.

[0060] If the mains power network 14 is in a normal state, it will maintain its current operating status and operate according to the original power management logic. If the mains power network 14 is in an abnormal state, it proves that there is a safety hazard in the mains power network 14, and it needs to be isolated immediately.

[0061] S303: Disconnect the mains power network from the AC port.

[0062] In a specific implementation scenario, the mains power network 14 is in an abnormal state and sends a disconnect command to the first relay S1. The first relay S1 quickly disconnects, completely severing the power connection between the mains power network 14 and the AC port 11. This prevents abnormal mains power (such as high voltage or low frequency) from impacting the energy storage inverter 121, energy storage battery 123, and load 15, thus preventing equipment burnout or lifespan degradation. Please refer to Figure 3; the power flow in this situation is consistent with that shown in Figure 3.

[0063] S304: Check if the connection between the second inverter component and the AC port is disconnected; if not, proceed to step S305. If yes, proceed to step S307.

[0064] S305: Determine whether the first sum of the load power and the battery's maximum charging power is less than the maximum output power. If yes, proceed to step S306. If no, proceed to step S307.

[0065] S306: Keep the connection between the micro grid-connected inverter and the AC port disconnected.

[0066] In a specific implementation scenario, steps S304-S306 are basically the same as steps S202-S204 of the second embodiment of the photovoltaic power supply control method provided by the present invention, and will not be described again here.

[0067] S307: Determine whether the first sum of the load power and the battery's maximum charging power is greater than the second sum of the maximum output power and the maximum photovoltaic output power; if not, proceed to step S308.

[0068] S308: Connects the second inverter assembly and the AC port.

[0069] In a specific implementation scenario, steps S307-S308 are basically the same as steps S103-S104 of the first embodiment of the photovoltaic power supply control method provided by the present invention, and will not be described again here.

[0070] S309: Determine whether the first summation is greater than the second summation. If yes, proceed to step S310; otherwise, proceed to step S311.

[0071] In a specific implementation scenario, compare the maximum absorbable power (load power) of photovoltaic system 10. +Maximum battery charging power The maximum output power (grid-connected maximum output power) when combined with the first inverter component 12 and the second inverter component 13. +Maximum photovoltaic output power The size of ).

[0072] S310: Drives the first photovoltaic panel, micro grid-connected inverter, and mains network to supply power to the load and energy storage battery.

[0073] In a specific implementation scenario, if the first sum is greater than the second sum, the first inverter component 12 (first photovoltaic panel 122) and the second inverter component 13 (micro grid-connected inverter 131) are driven to output electrical energy simultaneously, with the first photovoltaic panel 122 and the second photovoltaic panel 132 outputting according to their actual maximum power. Since the second sum is less than the first sum, the output of the first inverter component 12 and the second inverter component 13 cannot meet the power demand of the load 15 and the energy storage battery 123. The power difference is supplemented by the mains network 14 through the first relay S1 in the conducting state input AC Port 11. After integrating all the electrical energy, the AC Port 11 delivers it all to the load 15 and the energy storage battery 123. Please refer to Figure 7, which is a schematic diagram of the power supply flow when the first sum is greater than the second sum according to the present invention. By supplementing the photovoltaic power supply gap through the mains network 14, the normal power consumption of the load 15 and the charging of the battery as needed are ensured, avoiding power outages due to insufficient photovoltaic power.

[0074] S311: Drives the first photovoltaic panel and the micro grid-connected inverter to supply power to the load, energy storage battery and the mains network.

[0075] In a specific implementation scenario, if the first sum is less than or equal to the second sum, the first inverter component 12 (first photovoltaic panel 122) and the second inverter component 13 (micro grid-connected inverter 131) simultaneously output electrical energy, with the first photovoltaic panel 122 and the second photovoltaic panel 132 outputting according to their actual maximum power. Since the second sum is greater than or equal to the first sum, the total supply meets the demand of "load 15 + battery charging" with a surplus. The AC port 11 first allocates electrical energy to meet the charging needs of load 15 and energy storage battery 123, and the remaining surplus power is fed into the mains network 14 through the closed first relay S1. Please refer to Figure 8, which is a schematic diagram of the power supply flow when the first sum is less than or equal to the second sum provided by the present invention. The excess power is fed into the mains network to maximize the utilization of dual-path photovoltaic energy. After meeting its own power consumption and energy storage needs, the excess power is grid-connected for monetization, improving the utilization efficiency of photovoltaic resources and user benefits.

[0076] As described above, in this embodiment, when photovoltaic supply is insufficient, the grid power network is linked to supplement the power gap, ensuring continuous and stable power supply to the load and charging of the energy storage battery as needed, thus avoiding power outages. When photovoltaic supply is sufficient, after meeting its own power consumption and energy storage needs, the excess power is fed back into the grid power network, maximizing the utilization value of photovoltaic resources and creating additional benefits for users. At the same time, the system power balance is maintained throughout the process, taking into account power supply reliability, photovoltaic energy utilization rate and user economy, and fully adapting to the core operating requirements of grid-connected photovoltaic energy storage systems.

[0077] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A photovoltaic power supply control method, characterized in that, An application is made in a photovoltaic system, the photovoltaic system comprising: an AC port; a first inverter assembly and a second inverter assembly connected in parallel through the AC port, the first inverter assembly comprising an energy storage inverter, and a first photovoltaic panel and an energy storage battery connected to the energy storage inverter, the second inverter assembly comprising a micro grid-connected inverter, and a second photovoltaic panel connected to the micro grid-connected inverter; a mains power grid connected to the AC port; and a load connected to the AC port; the photovoltaic power supply control method comprises the following steps: detecting whether the connection between the mains power grid and the AC port is disconnected; if so, detecting whether the connection between the second inverter assembly and the AC port is disconnected; if so, collecting the maximum grid-connected output power of the micro grid-connected inverter, the maximum photovoltaic output power of the first photovoltaic panel, the load power of the load, and the maximum battery charging power of the energy storage battery, and determining whether a first sum of the load power and the maximum battery charging power is greater than a second sum of the maximum output power and the maximum photovoltaic output power; if so, connecting the second inverter assembly and the AC port.

2. The photovoltaic power supply control method according to claim 1, characterized in that, The step of closing the connection between the second inverter component and the AC port includes: waiting for a preset time before performing the step of closing the connection between the second inverter component and the AC port.

3. The photovoltaic power supply control method according to claim 2, characterized in that, The preset duration is 1 minute.

4. The photovoltaic power supply control method according to claim 1, characterized in that, After the step of detecting whether the connection between the second inverter component and the AC port is disconnected, the method includes: if not, determining whether the first sum of the load power and the maximum charging power of the battery is less than the maximum grid-connected output power; if yes, disconnecting the connection between the micro grid-connected inverter and the AC port.

5. The photovoltaic power supply control method according to claim 1, characterized in that, The step of detecting whether the connection between the mains power network and the AC port is disconnected includes: if not, detecting whether the mains power network is in a normal state; if not, disconnecting the connection between the mains power network and the AC port.

6. The photovoltaic power supply control method according to claim 5, characterized in that, After the step of detecting whether the mains power network is in a normal state, the method includes: if so, determining whether the first summation is greater than the second summation; if so, driving the first photovoltaic panel, the micro grid-connected inverter, and the mains power network to supply power to the load and the energy storage battery.

7. The photovoltaic power supply control method according to claim 5, characterized in that, After determining whether the first summation is greater than the second summation, the method includes: if not, driving the first photovoltaic panel and the micro grid-connected inverter to supply power to the load, the energy storage battery and the mains network.

8. The photovoltaic power supply control method according to claim 5, characterized in that, After the step of disconnecting the mains power network from the AC port, the method includes: driving the first photovoltaic panel and the micro grid-connected inverter to supply power to the load and the energy storage battery.

9. A photovoltaic system, characterized in that, The photovoltaic system includes: an AC port; at least one set of first inverter components and at least one set of second inverter components connected in parallel through the AC port, wherein the first inverter components include an energy storage inverter, a first photovoltaic panel and an energy storage battery connected to the energy storage inverter, and the second inverter components include a micro grid-connected inverter and a second photovoltaic panel connected to the micro grid-connected inverter; a mains power network connected to the AC port; and a load connected to the AC port; the photovoltaic system is used to perform the method according to any one of claims 1-7.

10. The photovoltaic system according to claim 9, characterized in that, The mains power network is connected to the AC port via a first relay; the load is connected to the AC port via a second relay; and the miniature grid-connected inverter is connected to the AC port via a third relay.

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