Non-feed network light storage air conditioning system and control method

Abstract

The invention discloses a non-feed network light storage air conditioning system and a control method thereof. The system comprises a direct current boosting module, a power factor correction (PFC) module, a direct current bus, a first inversion module, a second inversion module, an air conditioning compressor, a photovoltaic module, a direct current load, an alternating current load and a direct current energy storage module. The alternating-current power grid is connected to one end of the direct-current bus through the PFC module, and the other end of the direct-current bus is connected with the air conditioner compressor through the second inversion module; the photovoltaic assembly is connected to the DC bus through the DC boost module, and the DC bus is connected to the AC load through the first inversion module. The direct-current load is connected to the direct-current bus and the direct-current energy storage module respectively; the DC boost module and the PFC module adjust the power of the photovoltaic module, supply power to the DC energy storage module and control the connection and disconnection with the AC power grid based on the shared state information of the photovoltaic module, the AC / DC load and the energy storage module. According to the invention, the problem of serious insufficient consumption of photovoltaic grid connection can be effectively relieved, and photovoltaic power is prevented from flowing back to the power grid.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically to a non-grid photovoltaic-storage air conditioning system and its control method. Background Technology

[0002] With the accelerated global energy structure transformation, photovoltaic (PV) power generation technology is widely applied in the air conditioning field, forming two major technical paths: grid-connected PV air conditioners and off-grid PV air conditioners. Existing grid-connected PV air conditioners convert direct current (DC) into alternating current (AC) that conforms to the grid frequency and voltage through built-in inverter circuits, enabling them to feed power to the grid. However, this technical path requires strict adherence to national grid connection standards, involving certification of multiple technical indicators such as harmonic control, islanding protection, and voltage fluctuation regulation, leading to extended product development cycles and increased certification costs.

[0003] In recent years, there has been a severe shortage of photovoltaic power, and related policies have restricted grid connection of photovoltaic power, requiring grid-connected projects to be equipped with energy storage facilities or participate in electricity market transactions, indirectly raising the application threshold for grid-connected photovoltaic air conditioners. Against this backdrop, off-grid air conditioners that do not supply power to the grid have emerged.

[0004] However, conventional off-grid air conditioners, because they do not participate in grid connection, typically lack inverter circuits and energy storage modules in their hardware. Their external power supply interface is only a DC load power supply interface, meaning they cannot supply power to the grid or AC loads. Furthermore, preventing photovoltaic power from flowing back into the AC grid through a bidirectional converter is a pressing issue that needs to be addressed if off-grid air conditioners are to supply power to AC loads. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a non-grid-fed photovoltaic-storage-air conditioning system and its control method. This addresses the problem that existing non-grid-fed photovoltaic-storage-air conditioning systems have a single power consumption mode and cannot maximize the utilization of photovoltaic power. It effectively alleviates the severe insufficient absorption of photovoltaic power by the grid and fundamentally eliminates the possibility of generating electricity to the grid, truly achieving anti-reverse current protection for photovoltaic power.

[0006] The present invention adopts the following technical solution.

[0007] According to a first aspect of the present invention, a non-grid-fed photovoltaic-storage air conditioning system is provided. The system includes a DC boost module, a power factor correction (PFC) module, a DC bus, a first inverter module, a second inverter module, an air conditioning compressor, photovoltaic modules, and a DC energy storage module. The AC power grid is connected to one end of the DC bus through the PFC module, and the other end of the DC bus is connected to the air conditioner compressor through the second inverter module; The photovoltaic module is connected to the DC bus via the DC boost module, and the DC bus is connected to the AC load via the first inverter module; The DC load is connected to the DC bus and the DC energy storage module, respectively. The DC boost module and the PFC module acquire and share the status information of the photovoltaic module, the status information of the DC load and the AC load, and the state of charge information of the DC energy storage module. Based on the shared status information, they adjust the power of the photovoltaic module, the power supply to the DC energy storage module, and control the connection and disconnection with the AC grid to minimize the amount of electricity obtained from the AC grid.

[0008] Furthermore, the PFC module and the first inverter module are connected to the DC boost module via a communication link.

[0009] Furthermore, the PFC module collects the state of charge information of the DC energy storage module and the state information of the DC load and shares them with the DC boost module; The first inverter module collects the status information of the AC load and shares it with the DC boost module.

[0010] Furthermore, when the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module is greater than or equal to the charging cutoff threshold, the PFC module is disconnected from the grid, and the DC boost module reduces the power generation of the photovoltaic module to the sum of the load power of the DC load, the first inverter module, and the second inverter module through MPPT optimization control.

[0011] Furthermore, when the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module is less than the charging cutoff threshold, the PFC module is disconnected from the grid. The DC boost module increases the power generation of the photovoltaic module or maintains it at the maximum power point through MPPT optimization control until the state of charge of the DC energy storage module reaches the charging cutoff threshold. Then, the power generation of the photovoltaic module is reduced to be equal to the sum of the load power of the DC load, the first inverter module, and the second inverter module through MPPT optimization control.

[0012] Furthermore, when the power generation of the photovoltaic module is greater than 0 but less than the sum of the load power of the DC load, the first inverter module and the second inverter module, the DC boost module increases the output power of the DC bus or keeps the photovoltaic module at its maximum power point through MPPT optimization control.

[0013] Furthermore, if the power of the photovoltaic module at its maximum power point is less than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module is greater than the power supply cutoff threshold, then the PFC module is disconnected from the AC grid. If the power of the photovoltaic module at its maximum power point is less than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold, then the PFC module is connected to the AC grid.

[0014] Furthermore, when the power generation of the photovoltaic module is 0 and the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold, the PFC module is connected to the AC grid so that the DC energy storage module is in a charging state.

[0015] Furthermore, when the photovoltaic module generates zero power and the DC energy storage module has a state of charge greater than the power supply cutoff threshold, the DC energy storage module supplies power to the AC load.

[0016] According to a second aspect of the present invention, a control method for a non-grid photovoltaic-storage-air conditioning system based on the first aspect of the present invention is provided. The method includes the following steps: The DC boost module and the PFC module acquire and share the status information of the photovoltaic module, the status information of the DC load and the AC load, and the state of charge information of the DC energy storage module; Based on shared state information, the DC boost module and the PFC module adjust the power of the photovoltaic module, the power supply to the DC energy storage module, and control the connection and disconnection with the AC grid, so as to minimize the amount of electricity obtained from the AC grid.

[0017] Furthermore, the method also includes: when the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module and the second inverter module, and the state of charge of the DC energy storage module is greater than or equal to the charging cutoff threshold, the PFC module is disconnected from the grid, and the DC boost module reduces the power generation of the photovoltaic module to be equal to the sum of the load power of the DC load, the first inverter module and the second inverter module through MPPT optimization control.

[0018] Furthermore, the method further includes: when the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module and the second inverter module, and the state of charge of the DC energy storage module is less than the charging cutoff threshold, the PFC module is disconnected from the grid, the DC boost module increases the power generation of the photovoltaic module or maintains it at the maximum power point through MPPT optimization control until the state of charge of the DC energy storage module reaches the charging cutoff threshold, and then reduces the power generation of the photovoltaic module to be equal to the sum of the load power of the DC load, the first inverter module and the second inverter module through MPPT optimization control.

[0019] Furthermore, the method also includes: when the power generation of the photovoltaic module is greater than 0 but less than the sum of the load power of the DC load, the first inverter module and the second inverter module, the DC boost module increases the output power of the DC bus or keeps the photovoltaic module at its maximum power point through MPPT optimization control.

[0020] If the state of charge of the DC energy storage module is greater than the power supply cutoff threshold when the photovoltaic module is at its maximum power point, then the PFC module is disconnected from the AC grid. If the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold when the photovoltaic module is maintained at the maximum power point, then the PFC module is connected to the AC power grid.

[0021] Furthermore, the method also includes: when the power generation of the photovoltaic module is 0 and the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold, the PFC module is connected to the AC grid so that the DC energy storage module is in a charging state.

[0022] Furthermore, the method also includes: when the power generation of the photovoltaic module is 0 and the state of charge of the DC energy storage module is greater than the power supply cutoff threshold, the DC energy storage module supplies power to the off-grid photovoltaic-storage-air conditioning system.

[0023] The beneficial effects of this invention are that, compared with the prior art, 1. It can effectively alleviate the severe problem of insufficient grid absorption of photovoltaic power. By acquiring and sharing the status information of the photovoltaic modules, the DC load, the AC load, and the state of charge of the DC energy storage module through the DC boost module and the PFC module, and adjusting the power of the photovoltaic modules, the power supply to the DC energy storage module, and controlling the connection and disconnection with the AC grid based on the shared status information, it can realize the first inverter circuit supplying power to the AC load, the DC bus directly supplying power to the DC load, and the DC bus charging the DC energy storage module. At the same time, combined with the adjustment and optimization power of the DC boost module, it can maximize the utilization of photovoltaic energy, effectively alleviate the problem of insufficient photovoltaic power absorption, and minimize the amount of electricity obtained from the AC grid.

[0024] 2. Effectively avoid photovoltaic power backflow; by replacing the DC / AC bidirectional conversion module with a power factor correction (PFC) module and connecting it to the grid, and by setting up a first inverter module between the DC bus and the AC load, the possibility of photovoltaic modules supplying power to the grid can be fundamentally eliminated, realizing unidirectional power supply from the grid to the load and energy storage. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the non-feed grid photovoltaic storage air conditioning system of the present invention; Figure 2 This is the control logic diagram of the non-feed grid photovoltaic-storage air conditioning system of the present invention.

[0026] Among them, 10 is a non-grid-fed photovoltaic-storage-air conditioning system, 20 is an AC load, 30 is the power grid, 40 is a DC load, 11 is a photovoltaic module, 12 is a photovoltaic air conditioner, 13 is a DC energy storage module, 121 is a DC boost module, 122 is the first inverter module, 123 is an air conditioning compressor, 124 is the second inverter module, 125 is a DC bus, and 126 is a PFC module. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0028] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0029] In the following description, the terms "first" and "second" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first" and "second" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0030] Unless otherwise defined, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in the embodiments of this application is for the purpose of describing the embodiments of this application only and is not intended to limit this application.

[0031] In existing off-grid air conditioning systems, because they do not participate in grid connection, the hardware typically lacks inverter circuits and energy storage modules. The only external power supply interface is a DC load power supply interface, meaning that while they cannot feed power to the grid, they also cannot supply power to AC loads. Therefore, preventing photovoltaic power from flowing back into the AC grid through a bidirectional converter is a pressing issue that needs to be addressed if off-grid air conditioning systems are to supply power to AC loads.

[0032] Therefore, according to a first aspect of the present invention, a non-grid-fed air conditioning system is provided to effectively alleviate the severe insufficient absorption of photovoltaic power by grid connection, and to completely avoid the reverse flow of photovoltaic power to the grid while supplying power to AC loads.

[0033] Example 1 See attached document Figure 1 In this embodiment, the off-grid photovoltaic-storage air conditioning system 10 of the present invention includes: a DC boost module 121, a power factor correction (PFC) module 126, a DC bus 125, a first inverter module 122, a second inverter module 124, an air conditioning compressor 123, a photovoltaic module 11, and a DC energy storage module 13. The DC boost module 121, the PFC module 126, the DC bus 125, the first inverter module 122, the second inverter module 124, and the air conditioning compressor 123 form a photovoltaic air conditioning system 12. The photovoltaic module 11 and the DC energy storage module 13 are detachably connected to the photovoltaic air conditioning system 12.

[0034] The AC power grid 30 is connected to one end of the DC bus 125 through the PFC module 126, and the other end of the DC bus 125 is connected to the air conditioner compressor 123 through the second inverter module 124. The photovoltaic module 11 is connected to the DC bus 125 through the DC boost module 121, and the DC bus 125 is connected to the AC load 20 through the first inverter module 122; The DC load 40 is connected to the DC bus 125 and the DC energy storage module 13 respectively; The DC boost module 121 and the PFC module 126 acquire and share the status information of the photovoltaic module 11, the status information of the DC load 40 and the AC load 20, and the state of charge information of the DC energy storage module 13. Based on the shared status information, they adjust the power of the photovoltaic module 11, the power supply to the DC energy storage module 13, and control the connection and disconnection with the AC grid, so as to minimize the amount of electricity obtained from the AC grid 30.

[0035] In this embodiment, the DC boost module 121 is a standard accessory of the photovoltaic air conditioner 12, used to convert the DC input of the photovoltaic module 11 into a more stable DC input. This module has the MPPT adjustment function and can actively adjust the output power.

[0036] The first inverter module 122 is a standard component of the photovoltaic air conditioner 12 and is used to convert the DC power on the DC bus 125 into AC power to supply power to the AC load 20.

[0037] The second inverter module 124 is a standard component of the photovoltaic air conditioner 12 and is used to convert the DC power on the DC bus 125 into AC power to drive the air conditioner compressor.

[0038] PFC module 126 is a standard accessory of photovoltaic air conditioner 12. It is connected to AC grid 30 and is used to convert AC power from AC grid 30 into DC power to supply power to DC load 40 and second inverter module 124.

[0039] The DC energy storage module 13 is charged and outputs DC power, and can be directly charged by the DC bus; it can also be directly connected to the DC bus.

[0040] In this embodiment, the DC boost module 121 and the PFC module 126 acquire and share the status information of the photovoltaic module 11, the DC load 40 and the AC load 20, and the state of charge information of the DC energy storage module 13. Based on the shared status information, the power of the photovoltaic module 11, the power supplied to the DC energy storage module 13, and the connection and disconnection with the AC grid are adjusted. This enables the DC / AC inverter circuit to supply power to the AC load 20, the DC bus 125 to directly supply power to the DC load, and the DC bus 125 to charge the DC energy storage module 13. Simultaneously, by combining the power optimization adjustment of the DC boost module 121, the utilization of photovoltaic energy can be maximized, effectively alleviating the problem of insufficient photovoltaic power absorption and minimizing the amount of electricity obtained from the AC grid. Furthermore, by replacing the DC / AC bidirectional conversion module with a power factor correction (PFC) module and connecting it to the grid, and by setting up a first inverter module between the DC bus and the AC load, the possibility of photovoltaic modules supplying power to the grid can be fundamentally eliminated, realizing unidirectional power supply from the grid to the load and energy storage.

[0041] Example 2 This embodiment provides a non-grid-fed photovoltaic-storage-air conditioning system 10. This non-grid-fed photovoltaic-storage-air conditioning system is a further improvement on the system described in Embodiment 1.

[0042] Preferably, the PFC module 126 and the first inverter module 122 are connected to the DC boost module 121 via a communication link. More preferably, the PFC module 126 collects and shares the state of charge information of the DC energy storage module 13 and the state information of the DC load 40 with the DC boost module 121; simultaneously, the first inverter module 122 collects and shares the state information of the AC load 20 with the DC boost module 121.

[0043] Figure 2 The control logic diagram of the non-feed grid photovoltaic storage air conditioning system of this embodiment is shown.

[0044] When the power generation of the photovoltaic module 11 is greater than the sum of the load power of the DC load 40, the first inverter module 122, and the second inverter module 124, and the state of charge of the DC energy storage module 13 is greater than or equal to the charging cutoff threshold, it indicates that the photovoltaic power generation is too abundant. In other words, at this time, the photovoltaic power generation completely covers the power demand of the air conditioner compressor 123, the AC load 30, and the DC load 40, and the DC energy storage module 13 is also fully charged with a surplus. Accordingly, the PFC module 126 is disconnected from the AC power grid 30, and the DC boost module 121 reduces the power generation of the photovoltaic module 11 to the sum of the load power of the DC load 40, the first inverter module 122, and the second inverter module 124 through MPPT optimization control.

[0045] This reduces the power output of photovoltaic power generation, thus maximizing the utilization of photovoltaic energy.

[0046] When the power generation of the photovoltaic module 11 is greater than the sum of the load power of the DC load 40, the first inverter module 122, and the second inverter module 124, and the state of charge of the DC energy storage module 13 is greater than the charging cutoff threshold, it indicates that the photovoltaic power generation is sufficient, but the DC energy storage module 13 is not fully charged. Accordingly, the PFC module 126 is disconnected from the AC grid 30, and the DC boost module 121 increases the power generation of the photovoltaic module 11 or maintains it at the maximum power point through MPPT optimization control until the state of charge of the DC energy storage module 13 reaches the charging cutoff threshold. Then, through MPPT optimization control, the power generation of the photovoltaic module 11 is reduced to be equal to the sum of the load power of the DC load 40, the first inverter module 122, and the second inverter module 124.

[0047] In this way, the off-grid photovoltaic-storage air conditioning system 10 can draw all its power from the photovoltaic modules 11, leaving the AC grid 30 idle. The photovoltaic power is converted into more stable DC power by the DC boost module 121 and fed into the DC bus 125. The power on the DC bus 125 can be directly used to power the DC load, drive the air conditioning compressor through the second inverter module 124, and be converted into AC power by the first inverter module 122 to power the AC load 20. The DC energy storage module 13 is charged by the DC bus 125 after meeting the power supply needs of all other loads. After being fully charged, the DC energy storage module 13 is idle and in a state of neither charging nor discharging.

[0048] When the power generation of the photovoltaic module is greater than 0 but less than the sum of the load power of the DC load, the first inverter module, and the second inverter module, it indicates that the photovoltaic power is insufficient. Accordingly, the DC boost module 121 increases the output power of the DC bus 125 or keeps the photovoltaic module 11 at its maximum power point through MPPT optimization control.

[0049] In this way, the photovoltaic power can not only supply power to the DC load 40, the first inverter module 122, and the second inverter module 124, but also strive to supply power to the DC energy storage module 13. The process of supplying power to the DC energy storage module 13 also relies on the MPPT optimization control of the DC boost module 121. Specifically, when the state of charge of the DC energy storage module 13 is less than the charging cutoff threshold, the DC boost module 121 uses MPPT optimization control to maximize the charging current of the DC energy storage module 13 while not exceeding the rated charging current; when the state of charge of the DC energy storage module 13 is greater than or equal to the charging cutoff threshold, the DC boost module 121 uses MPPT optimization control to adjust the power generation of the photovoltaic module 11 to be equal to the sum of the load power of the DC load 40, the first inverter module 122, and the second inverter module 124.

[0050] If the power of the photovoltaic module 11 at its maximum power point is less than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module 13 is greater than the power supply cutoff threshold, it indicates that the photovoltaic power is insufficient, but the DC energy storage module 13 can supply power. Accordingly, the PFC module 126 is disconnected from the AC grid.

[0051] In this way, the system prioritizes drawing power from the photovoltaic module 11, with any shortfall automatically supplemented by the DC energy storage module 13, leaving the AC grid 30 idle. The photovoltaic power is converted into more stable DC power by the DC boost module 121 and fed into the DC bus. The power on the DC bus 125 can be directly supplied to DC loads, used to drive the air conditioner compressor via the second inverter module 124, and converted into AC power by the first inverter module 122 to supply AC load 20.

[0052] If the power of the photovoltaic module 11 at its maximum power point is less than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module 13 is less than or equal to the power supply cutoff threshold, it indicates insufficient photovoltaic power supply, and the DC energy storage module 13 is unable to supply power due to insufficient charge. Accordingly, the PFC module 126 is connected to the AC power grid 30.

[0053] In this way, the photovoltaic air conditioner preferentially draws power from the photovoltaic module 11, with the remaining power supplied by the AC grid 30. The grid also feeds into the DC bus 125 via the PFC module 126 to charge the DC energy storage module 13. The photovoltaic power is converted into more stable DC power by the DC boost module 121 and fed into the DC bus 125. The AC power from the AC grid 30 is converted into DC power by the PFC module 126 and fed into the DC bus 125. The power on the DC bus 125 can directly power the DC load 40, and simultaneously drives the air conditioner compressor 123 via the second inverter module 124, converting it into AC power via the first inverter module 122 to power the AC load 20.

[0054] When the photovoltaic module's power generation is 0 and the state of charge of the DC energy storage module 13 is less than or equal to the power supply cutoff threshold, it indicates that the photovoltaic cannot generate electricity (e.g., at night), and the DC energy storage capacity is insufficient. Accordingly, the PFC module 126 is connected to the AC power grid 30 to put the DC energy storage module 13 into a charging state.

[0055] In this way, the photovoltaic air conditioner 12 draws power from the AC grid 30, which also feeds into the DC bus 125 via the PFC module 126 to charge the DC energy storage module 13. The AC power from the AC grid 30 is converted into DC power by the PFC module 126 and fed into the DC bus 125. The power on the DC bus 125 can directly power the DC load 40, and at the same time, it drives the air conditioner compressor through the second inverter module 124, and is converted into AC power by the first inverter module 122 to power the AC load 20.

[0056] When the photovoltaic module 11 generates zero power and the state of charge of the DC energy storage module is greater than the power supply cutoff threshold, it indicates that the photovoltaic system cannot generate power (e.g., at night), but the DC energy storage module 13 can still supply power. Accordingly, the DC energy storage module 13 supplies power to the off-grid photovoltaic-storage-air conditioning system.

[0057] In this way, the photovoltaic air conditioner 12 draws all its power from the DC energy storage module 13, leaving the power grid idle. The DC power output from the DC energy storage module 13 is directly fed into the DC bus 125, and the power on the DC bus 125 can directly power the DC load 40. At the same time, the second inverter module 124 drives the air conditioner compressor 123, and the first inverter module 122 converts it into AC power to power the AC load 20.

[0058] Example 3 This embodiment provides a control method for a non-grid photovoltaic-storage air conditioning system based on the present invention. The method includes: The DC boost module and the PFC module acquire and share the status information of the photovoltaic module, the status information of the DC load and the AC load, and the state of charge information of the DC energy storage module; Based on shared state information, the DC boost module and the PFC module adjust the power of the photovoltaic module, the power supply to the DC energy storage module, and control the connection and disconnection with the AC grid, so as to minimize the amount of electricity obtained from the AC grid.

[0059] The DC boost module and the PFC module, based on shared state information, adjust the power of the photovoltaic module, the power supplied to the DC energy storage module, and control the connection and disconnection with the AC grid to minimize the amount of electricity obtained from the AC grid. Specifically, this includes: When the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module and the second inverter module, and the state of charge of the DC energy storage module is greater than or equal to the charging cutoff threshold, the PFC module is disconnected from the grid, and the DC boost module reduces the power generation of the photovoltaic module to the sum of the load power of the DC load, the first inverter module and the second inverter module through MPPT optimization control.

[0060] When the power generation of the photovoltaic module is greater than the sum of the load power of the DC load, the first inverter module, and the second inverter module, and the state of charge of the DC energy storage module is less than the charging cutoff threshold, the PFC module is disconnected from the grid. The DC boost module increases the power generation of the photovoltaic module or maintains it at the maximum power point through MPPT optimization control until the state of charge of the DC energy storage module reaches the charging cutoff threshold. Then, the power generation of the photovoltaic module is reduced to be equal to the sum of the load power of the DC load, the first inverter module, and the second inverter module through MPPT optimization control.

[0061] When the power generation of the photovoltaic module is greater than 0 but less than the sum of the load power of the DC load, the first inverter module and the second inverter module, the DC boost module increases the output power of the DC bus or keeps the photovoltaic module at its maximum power point through MPPT optimization control.

[0062] If the state of charge of the DC energy storage module is greater than the power supply cutoff threshold when the photovoltaic module is at its maximum power point, then the PFC module is disconnected from the AC grid. If the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold when the photovoltaic module is maintained at the maximum power point, then the PFC module is connected to the AC power grid.

[0063] When the power generation of the photovoltaic module is 0 and the state of charge of the DC energy storage module is less than or equal to the power supply cutoff threshold, the PFC module is connected to the AC grid so that the DC energy storage module is in a charging state.

[0064] When the power generation of the photovoltaic module is 0 and the state of charge of the DC energy storage module is greater than the power supply cutoff threshold, the DC energy storage module supplies power to the off-grid photovoltaic-storage-air conditioning system.

[0065] In summary, the beneficial effects of the present invention are that, compared with the prior art, 1. It can effectively alleviate the severe problem of insufficient grid absorption of photovoltaic power. By acquiring and sharing the status information of the photovoltaic module 11, the DC load 40 and the AC load 20, and the state of charge information of the DC energy storage module 13 through the DC boost module 121 and the PFC module 126, and adjusting the power of the photovoltaic module 11, the power supplied to the DC energy storage module 13, and controlling the connection and disconnection with the AC grid based on the shared status information, it can realize the DC / AC inverter circuit supplying power to the AC load 20, the DC bus 125 directly supplying power to the DC load, and the DC bus 125 charging the DC energy storage module 13. At the same time, combined with the adjustment and optimization power of the DC boost module 121, the purpose of maximizing the utilization of photovoltaic energy can be achieved, effectively alleviating the problem of insufficient photovoltaic power absorption, and minimizing the amount of electricity obtained from the AC grid.

[0066] 2. Effectively avoid photovoltaic power backflow; by replacing the DC / AC bidirectional conversion module with a power factor correction (PFC) module and connecting it to the grid, and by setting up a first inverter module between the DC bus and the AC load, the possibility of photovoltaic modules supplying power to the grid can be fundamentally eliminated, realizing unidirectional power supply from the grid to the load and energy storage.

[0067] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0068] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0069] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0070] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A non-feed optical storage air conditioning system, characterized by, The system comprises a DC boost module, a power factor correction (PFC) module, a DC bus, a first inverter module, a second inverter module, an air conditioner compressor, a photovoltaic assembly and a DC energy storage module. An alternating current (AC) power grid is connected to one end of the DC bus through the PFC module, and the other end of the DC bus is connected to the air conditioner compressor through the second inverter module. The photovoltaic assembly is connected to the DC bus through the DC boost module, and the DC bus is connected to an AC load through the first inverter module. DC loads are connected to the DC bus and the DC energy storage module respectively, and the DC energy storage module is connected to the DC bus. The DC boost module and the PFC module acquire and share state information of the photovoltaic assembly, state information of the DC loads and the AC load, and state of charge (SOC) information of the DC energy storage module, and adjust power of the photovoltaic assembly, power supplied to the DC energy storage module, and connection and disconnection with the AC power grid based on the shared state information, so as to minimize power obtained from the AC power grid.

2. The non-grid-connected photovoltaic energy storage air conditioner system according to claim 1, wherein the PFC module and the first inverter module are connected to the DC boost module through a communication link.

3. The non-grid-connected photovoltaic energy storage air conditioner system according to claim 1 or 2, wherein the PFC module collects SOC information of the DC energy storage module and state information of the DC loads and shares the information with the DC boost module; and the first inverter module collects state information of the AC load and shares the information with the DC boost module.

4. The non-grid-connected photovoltaic energy storage air conditioner system according to claim 1, wherein when power generated by the photovoltaic assembly is greater than the sum of load powers of the DC loads, the first inverter module and the second inverter module, and the SOC of the DC energy storage module is greater than or equal to a charging cutoff threshold, the PFC module is disconnected from the AC power grid, and the DC boost module reduces the power generated by the photovoltaic assembly to be equal to the sum of the load powers of the DC loads, the first inverter module and the second inverter module through MPPT optimization control.

5. The non-grid-connected photovoltaic energy storage air conditioner system according to claim 1, wherein when power generated by the photovoltaic assembly is greater than the sum of load powers of the DC loads, the first inverter module and the second inverter module, and the SOC of the DC energy storage module is less than the charging cutoff threshold, the PFC module is disconnected from the AC power grid, and the DC boost module increases the power generated by the photovoltaic assembly or keeps the power at a maximum power point until the SOC of the DC energy storage module reaches the charging cutoff threshold, and then reduces the power generated by the photovoltaic assembly to be equal to the sum of the load powers of the DC loads, the first inverter module and the second inverter module through MPPT optimization control.

6. The non-grid-connected photovoltaic energy storage air conditioner system according to claim 1, wherein ​ ​ ​ ​ ​ When the power generated by the photovoltaic assembly is greater than 0 but less than the sum of the load power of the DC load, the first inverter module and the second inverter module, the DC boost module increases the output power of the DC bus or keeps the photovoltaic assembly at the maximum power point through MPPT optimization control.

7. The non-grid-connected optical storage air conditioning system according to claim 6, wherein: If the power when the photovoltaic assembly is kept at the maximum power point is less than the sum of the load power of the DC load, the first inverter module and the second inverter module, and the state of charge of the DC energy storage module is greater than the energy supply cutoff threshold, the PFC module is disconnected from the AC power grid; If the power when the photovoltaic assembly is kept at the maximum power point is less than the sum of the load power of the DC load, the first inverter module and the second inverter module, and the state of charge of the DC energy storage module is less than or equal to the energy supply cutoff threshold, the PFC module is connected to the AC power grid.

8. The non-grid-connected optical storage air conditioning system according to claim 1, wherein: When the power generated by the photovoltaic assembly is 0, and the state of charge of the DC energy storage module is less than or equal to the energy supply cutoff threshold, the PFC module is connected to the AC power grid to make the DC energy storage module in the charging state.

9. The non-grid-connected optical storage air conditioning system according to claim 1, wherein: When the power generated by the photovoltaic assembly is 0, and the state of charge of the DC energy storage module is greater than the energy supply cutoff threshold, the DC energy storage module supplies power to the non-grid-connected optical storage air conditioning system.

10. A control method of the non-feed optical storage air conditioning system according to any one of claims 1 to 9, characterized by, The steps include: The DC boost module and the PFC module acquire and share the state information of the photovoltaic assembly, the state information of the DC load and the AC load, and the state of charge information of the DC energy storage module; The DC boost module and the PFC module adjust the power of the photovoltaic assembly, the power supplied to the DC energy storage module, and the connection and disconnection with the AC power grid based on the shared state information, so as to minimize the power obtained from the AC power grid.

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