A method, system and storage medium for controlling photovoltaic storage based on DC bus coupling

Abstract

The present invention provides a photovoltaic storage control method, system and storage medium based on DC bus coupling. First, the power generation power of a first photovoltaic cell array, i.e., first power information, and the power generation power information of a second photovoltaic cell array, i.e., second power information, are obtained, and the sum of the first power information and the second power information is calculated to obtain third power information; then, fourth power information is obtained, and it is determined whether the third power information exceeds the fourth power information; if so, the DC energy storage system is charged according to the fourth power information; if not, the DC energy storage system is set to discharge or connect to a mains power grid according to the fourth power information; the charging and discharging state of the DC energy storage system is controlled by DC bus coupling to improve the power generation utilization rate of the photovoltaic energy storage system, realize peak shaving and valley filling of the mains power grid, and improve the reliability of the power supply system.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic energy storage, and more specifically, to a photovoltaic energy storage control method, system and storage medium based on direct current bus coupling. Background Art

[0002] Photovoltaic storage system, also known as solar photovoltaic energy storage power generation system, is a power generation system composed of photovoltaic equipment and energy storage equipment; due to its technical maturity and economy, it is widely used in power systems and microgrid systems. It mainly includes photovoltaic components (such as solar panels), inverters (converting DC power into AC power), energy storage equipment (such as lithium-ion batteries, lead-acid batteries, etc.) and energy management systems. However, the use cost of the photovoltaic system is seriously affected by lighting conditions, the service life of photovoltaic panels and batteries, and the price difference during peak and trough power demand. Therefore, there is an urgent need for a photovoltaic storage control technology based on DC bus coupling that intelligently controls photovoltaic energy storage power generation and discharge. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a photovoltaic storage control method, system and storage medium based on DC bus coupling, using two photovoltaic cell arrays to perform solar photovoltaic energy storage power generation and energy storage, according to the power generation power of the two photovoltaic cell arrays and through DC bus coupling to control the charging and discharging state of the DC energy storage system, so as to improve the power generation utilization rate of the photovoltaic energy storage system, realize peak shaving and valley filling of the municipal power grid, and improve the reliability of the power supply system.

[0004] A first aspect of the present invention provides a photovoltaic storage control method based on DC bus coupling, the method comprising:

[0005] Acquire first power information and second power information;

[0006] Calculating the sum of the first power information and the second power information to obtain third power information;

[0007] acquiring fourth power information;

[0008] determining whether the third power information exceeds the fourth power information;

[0009] If yes, charging the DC energy storage system according to the fourth power information;

[0010] If not, the DC energy storage system is configured to discharge or connect to the mains power grid according to the fourth power information.

[0011] In this solution, charging the DC energy storage system according to the fourth power information is specifically:

[0012] determining whether the first power information exceeds the fourth power information;

[0013] If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system;

[0014] If not, calculating the difference between the third power information and the fourth power to obtain first power difference information;

[0015] Part of the first direct current is used to charge the direct current energy storage system according to the first power difference information.

[0016] In this solution, the DC energy storage system is set to discharge or connect to the mains power grid according to the fourth power information, specifically:

[0017] Calculating a difference between the fourth power information and the third power to obtain second power difference information;

[0018] Acquire first power information;

[0019] Determining whether the first power information exceeds a preset first power threshold;

[0020] If not, connecting to the mains power grid to transmit electric energy to the energy storage bidirectional converter;

[0021] If yes, determining first current information according to the first power information and the second power difference information;

[0022] The output current of the DC energy storage system is set according to the first current information to output electric energy to the energy storage bidirectional converter.

[0023] This plan also includes:

[0024] Acquire first power information;

[0025] Determining whether the first power information is lower than a preset second power threshold;

[0026] If yes, determining whether the third power information is lower than the fourth power information;

[0027] If so, the DC energy storage system is supplemented with electric energy through the second photovoltaic cell array or the power grid.

[0028] This plan also includes:

[0029] Acquire first power information;

[0030] Determining whether the first power information exceeds a preset third power threshold;

[0031] If yes, get the first time information;

[0032] According to the first time information, a preset peak-valley period corresponding table is searched to obtain first discharge power information;

[0033] Taking the first discharge power information as an upper limit value, the DC charging system is set to output electric energy to the energy storage bidirectional converter.

[0034] This plan also includes:

[0035] Determining whether the third power information is lower than a preset first power threshold;

[0036] If yes, get the first time information;

[0037] Searching a preset peak-valley period correspondence table according to the first time information to obtain first charging power information;

[0038] The DC energy storage system is charged through the mains power grid according to the first charging power information.

[0039] A second aspect of the present invention provides a photovoltaic storage control system based on DC bus coupling, including a photovoltaic storage control method program based on DC bus coupling, wherein the photovoltaic storage control method program based on DC bus coupling implements the following steps when executed by the processor:

[0040] Acquire first power information and second power information;

[0041] Calculating the sum of the first power information and the second power information to obtain third power information;

[0042] acquiring fourth power information;

[0043] determining whether the third power information exceeds the fourth power information;

[0044] If yes, charging the DC energy storage system according to the fourth power information;

[0045] If not, the DC energy storage system is configured to discharge or connect to the mains power grid according to the fourth power information.

[0046] In this solution, charging the DC energy storage system according to the fourth power information is specifically:

[0047] determining whether the first power information exceeds the fourth power information;

[0048] If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system;

[0049] If not, calculating the difference between the third power information and the fourth power to obtain first power difference information;

[0050] Part of the first direct current is used to charge the direct current energy storage system according to the first power difference information.

[0051] This plan also includes:

[0052] A third aspect of the present invention provides a computer-readable storage medium, which includes a photovoltaic storage control method program based on DC bus coupling. When the photovoltaic storage control method program based on DC bus coupling is executed by a processor, the steps of the photovoltaic storage control method based on DC bus coupling as described in any one of the above items are implemented.

[0053] The present invention provides a photovoltaic storage control method, system and storage medium based on DC bus coupling. First, the power generation power of a first photovoltaic cell array, i.e., first power information, and the power generation power information of a second photovoltaic cell array, i.e., second power information, are obtained, and the sum of the first power information and the second power information is calculated to obtain third power information; then, fourth power information is obtained, and it is determined whether the third power information exceeds the fourth power information; if so, the DC energy storage system is charged according to the fourth power information; if not, the DC energy storage system is set to discharge or connect to a mains power grid according to the fourth power information; the charging and discharging state of the DC energy storage system is controlled by DC bus coupling to improve the power generation utilization rate of the photovoltaic energy storage system, realize peak shaving and valley filling of the mains power grid, and improve the reliability of the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0055] Figure 1 A schematic diagram of a photovoltaic storage device based on DC bus coupling is shown;

[0056] Figure 2 A flow chart of a photovoltaic storage control method based on DC bus coupling of the present invention is shown;

[0057] Figure 3 A flow chart for charging a DC energy storage system provided by an embodiment of the present invention is shown;

[0058] Figure 4 A flow chart for supplying power to a load provided by an embodiment of the present invention is shown;

[0059] Figure 5 A block diagram of a photovoltaic storage control system based on DC bus coupling of the present invention is shown. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless the embodiments of the present invention are explicitly defined in this way.

[0062] The words "first", "second" and similar words used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" and similar words do not indicate a quantity limitation, but indicate the existence of at least one. Similarly, words such as "include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The steps before or after the method of the embodiment of the present invention are not necessarily carried out in order. On the contrary, various steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or a step or several steps can be removed from these processes.

[0063] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0064] Figure 1 A schematic diagram of a photovoltaic storage device based on DC bus coupling is shown.

[0065] like Figure 1 As shown, a photovoltaic storage device based on DC bus coupling includes:

[0066] A first photovoltaic cell array 102, a second photovoltaic cell array 104, a DC energy storage system 106, a DC bus 108, and an energy storage bidirectional converter 110;

[0067] The first photovoltaic cell array 102 is at least one group of solar cell groups, which generates a DC voltage and is then converted into a first AC voltage;

[0068] The second photovoltaic cell array 104 is a group of solar cells, which generates a DC voltage and is used to stabilize the voltage into a first DC voltage;

[0069] The DC energy storage system 106 is an energy storage battery, which is used to store electrical energy and release the second DC power;

[0070] The DC bus 108 is the operating channel of the photovoltaic storage DC power;

[0071] The energy storage bidirectional converter 110 is used to realize the conversion between AC and DC and control the flow direction of electric energy.

[0072] It should be noted that the first photovoltaic cell array 102 is converted into alternating current through a photovoltaic inverter, and together with the power grid, it is used as the input of the intelligent switching switch, and the intelligent switching switch can be switched to a non-output state, a photovoltaic output state, a grid output state, and a photovoltaic and grid simultaneous output state. The DC bus 108 transmits the electric energy generated by the second photovoltaic cell array 104 or the DC electric energy converted by the energy storage bidirectional converter 110 to the DC energy storage system 106 according to the charging demand; the DC bus 108 transmits the electric energy generated by the second photovoltaic cell array 104 or the electric energy of the DC energy storage system 106 to the energy storage bidirectional converter 110 according to the discharging demand.

[0073] Figure 2 A flow chart of a photovoltaic storage control method based on DC bus coupling of the present invention is shown.

[0074] like Figure 2 As shown, the present invention discloses a photovoltaic storage control method based on DC bus coupling, the method comprising:

[0075] S202, obtaining first power information and second power information;

[0076] S204, calculating the sum of the first power information and the second power information to obtain third power information;

[0077] S206, obtaining fourth power information;

[0078] S208, determining whether the third power information exceeds the fourth power information;

[0079] S210: If yes, charging the DC energy storage system according to the fourth power information;

[0080] S212: If not, setting the DC energy storage system to discharge or connect to the mains power grid according to the fourth power information.

[0081] It should be noted that the first power information is the power value generated and converted by the first photovoltaic cell array; the second power information is the power value generated and converted by the second photovoltaic cell array; the third power information P3 is the power value generated and converted by all photovoltaic cell arrays; the fourth power information is the real-time power value required for the load to work. When the photovoltaic power generation power is large or the load power is small, that is, the sum of the power generated by the first photovoltaic cell array and the power generated by the second photovoltaic cell array is greater than the load power, it means that the photovoltaic cell array power generation power meets the power consumption demand of the load and there is surplus, so the surplus power is charged to the DC energy storage system through the DC bus. When the photovoltaic power generation power is small or the load power is large, that is, the sum of the power generated by the first photovoltaic cell array and the power generated by the second photovoltaic cell array is less than the load power, it means that the photovoltaic cell array power generation power is insufficient to meet the power consumption demand of the load, so the power of the DC energy storage system is transmitted to the energy storage bidirectional converter through the DC bus or the power of the power grid is transmitted to the energy storage bidirectional converter through the intelligent switching switch, and finally the energy storage bidirectional converter selects and adjusts the power supplied to the load.

[0082] Figure 3 A flow chart of charging a DC energy storage system provided by an embodiment of the present invention is shown.

[0083] According to an embodiment of the present invention, Figure 3 As shown, charging the DC energy storage system according to the fourth power information is specifically:

[0084] S302, determining whether the first power information exceeds the fourth power information;

[0085] S304: If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system;

[0086] S306: If not, calculate the difference between the third power information and the fourth power to obtain first power difference information;

[0087] S308: Use part of the first direct current to charge the direct current energy storage system according to the first power difference information.

[0088] It should be noted that the first AC power is the AC power transmitted from the intelligent switching switch to the energy storage bidirectional converter; the first DC power is the DC power when the energy storage bidirectional converter charges the DC energy storage system; the first power difference information is the power value when the total power generated by the first photovoltaic cell array and the second photovoltaic cell array exceeds the load power. When the power generated by the photovoltaic cell array meets the power consumption demand of the load and there is surplus power, and the DC energy storage system is charged with the surplus power through the DC bus, first, it is determined whether the power converted from the first photovoltaic cell array into AC power through the photovoltaic inverter is greater than the power demand of the load; if so, the part of the power generated by the first photovoltaic cell array that exceeds the load power is converted into DC power through the energy storage bidirectional converter, and charged to the DC energy storage system through the DC bus. At the same time, all the power generated by the second photovoltaic cell array is charged to the DC energy storage system through the DC bus; if not, it means that the power generated by the first photovoltaic cell array is greater than the load power. The electric power is not enough to meet the load demand, and part of the luminous power of the second photovoltaic cell array needs to be used to supplement the load demand. That is to say, the difference between the total luminous power of the first photovoltaic cell array and the second photovoltaic cell array and the load power obtains the first power difference information, which is the power value of the DC electric energy converted by the second photovoltaic cell array for charging the DC energy storage system; finally, the DC energy storage system is charged through the DC bus according to the first power difference information; the remaining part of the power generated by the second photovoltaic cell array and all the power generated by the first photovoltaic cell array are transmitted to the energy storage bidirectional converter to power the load.

[0089] Figure 4 A flow chart of supplying power to a load provided by an embodiment of the present invention is shown.

[0090] According to an embodiment of the present invention, Figure 4 As shown, the DC energy storage system is set to discharge or connect to the mains power grid according to the fourth power information, specifically:

[0091] S402, calculating a difference between the fourth power information and the third power to obtain second power difference information;

[0092] S404, obtaining first power information;

[0093] S406, determining whether the first power information exceeds a preset first power threshold;

[0094] S408, if not, connecting to the mains power grid to transmit electric energy to the energy storage bidirectional converter;

[0095] S410: If yes, determining first current information according to the first power information and the second power difference information;

[0096] S412: Setting the output current of the DC energy storage system according to the first current information, and outputting electric energy to the energy storage bidirectional converter.

[0097] It should be noted that the second power difference information is the power value of the load power exceeding the total power generated by the first photovoltaic cell array and the second photovoltaic cell array; the first power information is the electric energy capacity stored in the DC energy storage system, usually expressed in the form of a voltage value; the first current information is the current value output by the DC energy storage system to the energy storage bidirectional converter through the DC bus, that is, the discharge current value. When the power generated by the photovoltaic cell array is not enough to meet the power consumption demand of the load, it is necessary to discharge through the DC energy storage system or enter the grid electricity to supplement the power consumption demand of the load. The difference between the fourth power information and the third power is calculated to obtain the second power difference information, which indicates the power demand supplemented by the discharge of the DC energy storage system or the power supply of the grid. Then, based on the remaining power of the DC energy storage system, that is, the first power information, it is determined whether the first power information exceeds a preset first power threshold; if not, it means that the power of the DC energy storage system is insufficient to support the operation of the load, so electric energy is provided through the power grid, and the load is powered by the energy storage bidirectional converter; if so, it means that the power of the DC energy storage system is sufficient. At this time, the output current value is obtained based on the remaining power of the DC energy storage system and the power that needs to be supplemented, and then the electric energy is transmitted to the energy storage bidirectional converter via the DC bus to supply power to the load.

[0098] According to an embodiment of the present invention, it also includes:

[0099] Acquire first power information;

[0100] Determining whether the first power information is lower than a preset second power threshold;

[0101] If yes, determining whether the third power information is lower than the fourth power information;

[0102] If yes, the grid supplies electric energy to the DC energy storage system;

[0103] If not, the second photovoltaic cell array generates electricity to supplement the DC energy storage system.

[0104] It should be noted that when the remaining power of the DC energy storage system is lower than the preset second power threshold, it means that the power value of the DC energy storage system is too low. In order to avoid the reduction of the service life of the DC energy storage system due to excessive discharge, the power grid is converted into DC power through the energy storage bidirectional converter, or the second photovoltaic cell array generates DC power, and supplies power to the DC energy storage system through the DC bus. When the total power generation power of the photovoltaic cell array is lower than the load power, the DC energy storage system is supplemented with electricity through the grid; when the total power generation power of the photovoltaic cell array is not lower than the load power, the second photovoltaic cell array is used to generate DC power, which is directly used to quickly supplement the DC energy storage system with electricity.

[0105] According to an embodiment of the present invention, it also includes:

[0106] Acquire first power information;

[0107] Determining whether the first power information exceeds a preset third power threshold;

[0108] If yes, get the first time information;

[0109] According to the first time information, a preset peak-valley period corresponding table is searched to obtain first discharge power information;

[0110] Taking the first discharge power information as an upper limit value, the DC charging system is set to output electric energy to the energy storage bidirectional converter.

[0111] It should be noted that the first time information shown is the time of the day. When the remaining power value of the DC energy storage system is higher than the preset third power threshold, it means that the power is fully charged and can release electric energy to the outside. If the power demand of this load is large and the DC energy storage system or the power grid needs to supplement the power demand, the first time information is obtained. According to the first time information, the preset peak-valley period correspondence table is queried to obtain the first discharge power information at the current moment; wherein, when the power grid is in the peak period, the DC energy storage system is set to output a larger power; when the power grid is in the valley period, the DC energy storage system is set to output a smaller power; peak-time discharge is used to reduce the demand for power supply to the power grid, thereby reducing the electricity cost during the peak period of the power grid.

[0112] According to an embodiment of the present invention, it also includes:

[0113] Determining whether the third power information is lower than a preset first power threshold;

[0114] If yes, get the first time information;

[0115] Searching a preset peak-valley period correspondence table according to the first time information to obtain first charging power information;

[0116] The DC energy storage system is charged through the mains power grid according to the first charging power information.

[0117] It should be noted that when the third power information, that is, the total power generated by the first photovoltaic cell array and the second photovoltaic cell array, is lower than the preset first power threshold, it means that the photovoltaic power generation power is insufficient to meet the charging demand of the DC energy storage system. For example, when the weather or equipment is blocked and other factors affect power generation, and it is necessary to supplement power to the DC energy storage system through the power grid, the preset peak-valley period correspondence table is queried according to the first time information to obtain the first charging power information at the current moment; wherein, when the power grid is in the valley period, the charging power of the DC energy storage system is set to be larger; when the power grid is in the peak period, the charging power of the DC energy storage system is set to be smaller; valley charging reduces the electricity cost of the power grid when charging the DC energy storage system.

[0118] It is worth mentioning that it also includes:

[0119] Determine whether the power grid is in an abnormal power outage state;

[0120] If yes, obtaining first power information;

[0121] Determining whether the first power information is lower than a preset fourth power threshold;

[0122] If yes, a low current output mode is set and a first abnormal instruction is sent.

[0123] It should be noted that when the power grid is in an abnormal state such as a power outage, it is determined whether the remaining power of the DC energy storage system is lower than the preset fourth power threshold; if so, it means that the power can no longer support the normal operation of the load for a long time. In order to avoid the load being completely out of power and affecting the production and living conditions of the user, the DC energy storage system will enter the trickle output state. When entering the trickle output state, the DC energy storage system only provides power output that allows the load to work in a standby state, and sends a first abnormal instruction to the background to promptly notify the user of the abnormal state.

[0124] It is worth mentioning that it also includes:

[0125] Acquiring first discharge cycle information;

[0126] Determining whether the first discharge cycle information exceeds a preset discharge cycle threshold;

[0127] If so, the DC charging system is configured to output electric energy to the energy storage bidirectional converter until the first electric quantity information drops to a preset third electric quantity threshold.

[0128] It should be noted that the first discharge cycle information is the length of time since the last discharge of the DC energy storage system. When the first discharge cycle information exceeds the preset discharge cycle threshold, it means that the DC energy storage system is in a long-term non-start state. In order to avoid the situation where the service life of the DC energy storage system is reduced due to long-term non-use, an active activation discharge method is adopted to set the DC energy storage system to output electric energy to the energy storage bidirectional converter until the first power information drops to the preset third power threshold.

[0129] Figure 5 A block diagram of a photovoltaic storage control system based on DC bus coupling of the present invention is shown.

[0130] like Figure 5 As shown, the present invention discloses a photovoltaic storage control system 5 based on DC bus coupling, including a memory 51 and a processor 52, wherein the memory includes a photovoltaic storage control method program based on DC bus coupling, and when the photovoltaic storage control method program based on DC bus coupling is executed by the processor, the following steps are implemented:

[0131] Acquire first power information and second power information;

[0132] Calculating the sum of the first power information and the second power information to obtain third power information;

[0133] acquiring fourth power information;

[0134] determining whether the third power information exceeds the fourth power information;

[0135] If yes, charging the DC energy storage system according to the fourth power information;

[0136] If not, the DC energy storage system is configured to discharge or connect to the mains power grid according to the fourth power information.

[0137] It should be noted that the first power information is the power value generated and converted by the first photovoltaic cell array; the second power information is the power value generated and converted by the second photovoltaic cell array; the third power information is the power value generated and converted by all photovoltaic cell arrays; and the fourth power information is the real-time power value required for the load to work. When the photovoltaic power generation power is large or the load power is small, that is, the sum of the power generated by the first photovoltaic cell array and the power generated by the second photovoltaic cell array is greater than the load power, it means that the photovoltaic cell array power generation power meets the power consumption demand of the load and there is surplus, so the surplus power is charged to the DC energy storage system through the DC bus. When the photovoltaic power generation power is small or the load power is large, that is, the sum of the power generated by the first photovoltaic cell array and the power generated by the second photovoltaic cell array is less than the load power, it means that the photovoltaic cell array power generation power is insufficient to meet the power consumption demand of the load, so the power of the DC energy storage system is transmitted to the energy storage bidirectional converter through the DC bus or the power of the power grid is transmitted to the energy storage bidirectional converter through the intelligent switching switch, and finally the energy storage bidirectional converter selects and adjusts the power supplied to the load.

[0138] According to an embodiment of the present invention, charging the DC energy storage system according to the fourth power information is specifically:

[0139] determining whether the first power information exceeds the fourth power information;

[0140] If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system;

[0141] If not, calculating the difference between the third power information and the fourth power to obtain first power difference information;

[0142] Part of the first direct current is used to charge the direct current energy storage system according to the first power difference information.

[0143] It should be noted that the first AC power is the AC power transmitted from the intelligent switching switch to the energy storage bidirectional converter; the first DC power is the DC power when the energy storage bidirectional converter charges the DC energy storage system; the first power difference information is the power value when the total power generated by the first photovoltaic cell array and the second photovoltaic cell array exceeds the load power. When the power generated by the photovoltaic cell array meets the power consumption demand of the load and there is surplus power, and the DC energy storage system is charged with the surplus power through the DC bus, first, it is determined whether the power converted from the first photovoltaic cell array into AC power through the photovoltaic inverter is greater than the power demand of the load; if so, the part of the power generated by the first photovoltaic cell array that exceeds the load power is converted into DC power through the energy storage bidirectional converter, and charged to the DC energy storage system through the DC bus. At the same time, all the power generated by the second photovoltaic cell array is charged to the DC energy storage system through the DC bus; if not, it means that the power generated by the first photovoltaic cell array is greater than the load power. The electric power is not enough to meet the load demand, and part of the luminous power of the second photovoltaic cell array needs to be used to supplement the load demand. That is to say, the difference between the total luminous power of the first photovoltaic cell array and the second photovoltaic cell array and the load power obtains the first power difference information, which is the power value of the DC electric energy converted by the second photovoltaic cell array for charging the DC energy storage system; finally, the DC energy storage system is charged through the DC bus according to the first power difference information; the remaining part of the power generated by the second photovoltaic cell array and all the power generated by the first photovoltaic cell array are transmitted to the energy storage bidirectional converter to power the load.

[0144] According to an embodiment of the present invention, setting the DC energy storage system to discharge or connect to the mains grid according to the fourth power information is specifically:

[0145] Calculating a difference between the fourth power information and the third power to obtain second power difference information;

[0146] Acquire first power information;

[0147] Determining whether the first power information exceeds a preset first power threshold;

[0148] If not, connecting to the mains power grid to transmit electric energy to the energy storage bidirectional converter;

[0149] If yes, determining first current information according to the first power information and the second power difference information;

[0150] The output current of the DC energy storage system is set according to the first current information to output electric energy to the energy storage bidirectional converter.

[0151] It should be noted that the second power difference information is the power value of the load power exceeding the total power generated by the first photovoltaic cell array and the second photovoltaic cell array; the first power information is the electric energy capacity stored in the DC energy storage system, usually expressed in the form of a voltage value; the first current information is the current value output by the DC energy storage system to the energy storage bidirectional converter through the DC bus, that is, the discharge current value. When the power generated by the photovoltaic cell array is not enough to meet the power consumption demand of the load, it is necessary to discharge through the DC energy storage system or enter the grid electricity to supplement the power consumption demand of the load. The difference between the fourth power information and the third power is calculated to obtain the second power difference information, which indicates the power demand supplemented by the discharge of the DC energy storage system or the power supply of the grid. Then, based on the remaining power of the DC energy storage system, that is, the first power information, it is determined whether the first power information exceeds a preset first power threshold; if not, it means that the power of the DC energy storage system is insufficient to support the operation of the load, so electric energy is provided through the power grid, and the load is powered by the energy storage bidirectional converter; if so, it means that the power of the DC energy storage system is sufficient. At this time, the output current value is obtained based on the remaining power of the DC energy storage system and the power that needs to be supplemented, and then the electric energy is transmitted to the energy storage bidirectional converter via the DC bus to supply power to the load.

[0152] According to an embodiment of the present invention, it also includes:

[0153] Acquire first power information;

[0154] Determining whether the first power information is lower than a preset second power threshold;

[0155] If yes, determining whether the third power information is lower than the fourth power information;

[0156] If yes, the grid supplies electric energy to the DC energy storage system;

[0157] If not, the second photovoltaic cell array generates electricity to supplement the DC energy storage system.

[0158] It should be noted that when the remaining power of the DC energy storage system is lower than the preset second power threshold, it means that the power value of the DC energy storage system is too low. In order to avoid the reduction of the service life of the DC energy storage system due to excessive discharge, the power grid is converted into DC power through the energy storage bidirectional converter, or the second photovoltaic cell array generates DC power, and supplies power to the DC energy storage system through the DC bus. When the total power generation power of the photovoltaic cell array is lower than the load power, the DC energy storage system is supplemented with electricity through the grid; when the total power generation power of the photovoltaic cell array is not lower than the load power, the second photovoltaic cell array is used to generate DC power, which is directly used to quickly supplement the DC energy storage system with electricity.

[0159] According to an embodiment of the present invention, it also includes:

[0160] Acquire first power information;

[0161] Determining whether the first power information exceeds a preset third power threshold;

[0162] If yes, get the first time information;

[0163] According to the first time information, a preset peak-valley period corresponding table is searched to obtain first discharge power information;

[0164] Taking the first discharge power information as an upper limit value, the DC charging system is set to output electric energy to the energy storage bidirectional converter.

[0165] It should be noted that the first time information shown is the time of the day. When the remaining power value of the DC energy storage system is higher than the preset third power threshold, it means that the power is fully charged and can release electric energy to the outside. If the power demand of this load is large and the DC energy storage system or the power grid needs to supplement the power demand, the first time information is obtained. According to the first time information, the preset peak-valley period correspondence table is queried to obtain the first discharge power information at the current moment; wherein, when the power grid is in the peak period, the DC energy storage system is set to output a larger power; when the power grid is in the valley period, the DC energy storage system is set to output a smaller power; peak-time discharge is used to reduce the demand for power supply to the power grid, thereby reducing the electricity cost during the peak period of the power grid.

[0166] According to an embodiment of the present invention, it also includes:

[0167] Determining whether the third power information is lower than a preset first power threshold;

[0168] If yes, get the first time information;

[0169] Searching a preset peak-valley period correspondence table according to the first time information to obtain first charging power information;

[0170] The DC energy storage system is charged through the mains power grid according to the first charging power information.

[0171] It should be noted that when the third power information, that is, the total power generated by the first photovoltaic cell array and the second photovoltaic cell array, is lower than the preset first power threshold, it means that the photovoltaic power generation power is insufficient to meet the charging demand of the DC energy storage system. For example, when the weather or equipment is blocked and other factors affect power generation, and it is necessary to supplement power to the DC energy storage system through the power grid, the preset peak-valley period correspondence table is queried according to the first time information to obtain the first charging power information at the current moment; wherein, when the power grid is in the valley period, the charging power of the DC energy storage system is set to be larger; when the power grid is in the peak period, the charging power of the DC energy storage system is set to be smaller; valley charging reduces the electricity cost of the power grid when charging the DC energy storage system.

[0172] It is worth mentioning that it also includes:

[0173] Determine whether the power grid is in an abnormal power outage state;

[0174] If yes, obtaining first power information;

[0175] Determining whether the first power information is lower than a preset fourth power threshold;

[0176] If yes, a low current output mode is set and a first abnormal instruction is sent.

[0177] It should be noted that when the power grid is in an abnormal state such as a power outage, it is determined whether the remaining power of the DC energy storage system is lower than the preset fourth power threshold; if so, it means that the power can no longer support the normal operation of the load for a long time. In order to avoid the load being completely out of power and affecting the production and living conditions of the user, the DC energy storage system will enter the trickle output state. When entering the trickle output state, the DC energy storage system only provides power output that allows the load to work in a standby state, and sends a first abnormal instruction to the background to promptly notify the user of the abnormal state.

[0178] It is worth mentioning that it also includes:

[0179] Acquiring first discharge cycle information;

[0180] Determining whether the first discharge cycle information exceeds a preset discharge cycle threshold;

[0181] If so, the DC charging system is configured to output electric energy to the energy storage bidirectional converter until the first electric quantity information drops to a preset third electric quantity threshold.

[0182] It should be noted that the first discharge cycle information is the length of time since the last discharge of the DC energy storage system. When the first discharge cycle information exceeds the preset discharge cycle threshold, it means that the DC energy storage system is in a long-term non-start state. In order to avoid the situation where the service life of the DC energy storage system is reduced due to long-term non-use, an active activation discharge method is adopted to set the DC energy storage system to output electric energy to the energy storage bidirectional converter until the first power information drops to the preset third power threshold.

[0183] A third aspect of the present invention provides a computer-readable storage medium, which includes a photovoltaic storage control method program based on DC bus coupling. When the photovoltaic storage control method program based on DC bus coupling is executed by a processor, the steps of the photovoltaic storage control method based on DC bus coupling as described in any one of the above items are implemented.

[0184] The present invention provides a photovoltaic storage control method, system and storage medium based on DC bus coupling. First, the power generation power of a first photovoltaic cell array, i.e., first power information, and the power generation power information of a second photovoltaic cell array, i.e., second power information, are obtained, and the sum of the first power information and the second power information is calculated to obtain third power information; then, fourth power information is obtained, and it is determined whether the third power information exceeds the fourth power information; if so, the DC energy storage system is charged according to the fourth power information; if not, the DC energy storage system is set to discharge or connect to a mains power grid according to the fourth power information; the charging and discharging state of the DC energy storage system is controlled by DC bus coupling to improve the power generation utilization rate of the photovoltaic energy storage system, realize peak shaving and valley filling of the mains power grid, and improve the reliability of the power supply system.

[0185] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

[0186] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photovoltaic storage control method based on DC bus coupling, applied to a photovoltaic storage device based on DC bus coupling, the photovoltaic storage device based on DC bus coupling comprising: A first photovoltaic cell array, a second photovoltaic cell array, a DC energy storage system, a DC bus, and an energy storage bidirectional converter; The first photovoltaic cell array is at least one group of solar cell groups, which generates a direct current voltage and is then converted into a first alternating current; The second photovoltaic cell array is a group of solar cell groups, which generates a DC voltage and is used to stabilize the voltage into a first DC voltage; The DC energy storage system is an energy storage battery, which is used to store electrical energy and release the second DC power; The DC bus is the operating channel of the photovoltaic storage DC power; The energy storage bidirectional converter is used to realize the conversion between AC and DC and control the flow direction of electric energy; Characterized in that the method comprises: Acquire first power information and second power information; Calculate the sum of the first power information and the second power information to obtain third power information; acquiring fourth power information; determining whether the third power information exceeds the fourth power information; If yes, charging the DC energy storage system according to the fourth power information; If not, setting the DC energy storage system to discharge or connect to the mains power grid according to the fourth power information; Acquire first power information; Determining whether the first power information exceeds a preset third power threshold; If yes, get the first time information; According to the first time information, a preset peak-valley period corresponding table is searched to obtain first discharge power information; Taking the first discharge power information as an upper limit value, setting the DC energy storage system to output electric energy to the energy storage bidirectional converter; Determining whether the third power information is lower than a preset first power threshold; If yes, get the first time information; Searching a preset peak-valley period correspondence table according to the first time information to obtain first charging power information; Charging the DC energy storage system through the mains power grid according to the first charging power information; Acquiring first discharge cycle information; Determining whether the first discharge cycle information exceeds a preset discharge cycle threshold; If so, the DC energy storage system is configured to output electric energy to the energy storage bidirectional converter until the first electric quantity information drops to a preset third electric quantity threshold.

2. The method for controlling a photovoltaic storage system based on DC bus coupling according to claim 1, characterized in that: The charging of the DC energy storage system according to the fourth power information is specifically: determining whether the first power information exceeds the fourth power information; If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system; If not, calculating the difference between the third power information and the fourth power to obtain first power difference information; Part of the first direct current is used to charge the direct current energy storage system according to the first power difference information.

3. The method for controlling a photovoltaic storage system based on DC bus coupling according to claim 1, characterized in that: The step of setting the DC energy storage system to discharge or connect to the mains power grid according to the fourth power information is specifically: Calculating a difference between the fourth power information and the third power to obtain second power difference information; Acquire first power information; Determining whether the first power information exceeds a preset first power threshold; If not, connecting to the mains power grid to transmit electric energy to the energy storage bidirectional converter; If yes, determining first current information according to the first power information and the second power difference information; The output current of the DC energy storage system is set according to the first current information to output electric energy to the energy storage bidirectional converter.

4. The method for controlling a photovoltaic storage system based on DC bus coupling according to claim 1, characterized in that: Also includes: Acquire first power information; Determining whether the first power information is lower than a preset second power threshold; If yes, determining whether the third power information is lower than the fourth power information; If so, the DC energy storage system is supplemented with electric energy through the second photovoltaic cell array or the power grid.

5. A photovoltaic storage control system based on DC bus coupling, applied to a photovoltaic storage device based on DC bus coupling, the photovoltaic storage device based on DC bus coupling comprising: A first photovoltaic cell array, a second photovoltaic cell array, a DC energy storage system, a DC bus, and an energy storage bidirectional converter; The first photovoltaic cell array is at least one group of solar cell groups, which generates a direct current voltage and is then converted into a first alternating current; The second photovoltaic cell array is a group of solar cell groups, which generates a DC voltage and is used to stabilize the voltage into a first DC voltage; The DC energy storage system is an energy storage battery, which is used to store electrical energy and release the second DC power; The DC bus is the operating channel of the photovoltaic storage DC power; The energy storage bidirectional converter is used to realize the conversion between AC and DC and control the flow direction of electric energy; The system comprises a memory and a processor, wherein the memory comprises a photovoltaic storage control method program based on DC bus coupling, and when the photovoltaic storage control method program based on DC bus coupling is executed by the processor, the following steps are implemented: Acquire first power information and second power information; Calculate the sum of the first power information and the second power information to obtain third power information; acquiring fourth power information; determining whether the third power information exceeds the fourth power information; If yes, charging the DC energy storage system according to the fourth power information; If not, setting the DC energy storage system to discharge or connect to the mains power grid according to the fourth power information; Acquire first power information; Determining whether the first power information exceeds a preset third power threshold; If yes, get the first time information; According to the first time information, a preset peak-valley period corresponding table is searched to obtain first discharge power information; Taking the first discharge power information as an upper limit value, setting the DC energy storage system to output electric energy to the energy storage bidirectional converter; Determining whether the third power information is lower than a preset first power threshold; If yes, get the first time information; Searching a preset peak-valley period correspondence table according to the first time information to obtain first charging power information; Charging the DC energy storage system through the mains power grid according to the first charging power information; Acquiring first discharge cycle information; Determining whether the first discharge cycle information exceeds a preset discharge cycle threshold; If so, the DC energy storage system is configured to output electric energy to the energy storage bidirectional converter until the first electric quantity information drops to a preset third electric quantity threshold.

6. The solar energy storage control system based on DC bus coupling according to claim 5 is characterized in that: The charging of the DC energy storage system according to the fourth power information is specifically: determining whether the first power information exceeds the fourth power information; If yes, converting the first alternating current of the set power into direct current to charge the direct current energy storage system; If not, calculating the difference between the third power information and the fourth power to obtain first power difference information; Part of the first direct current is used to charge the direct current energy storage system according to the first power difference information.

7. The solar energy storage control system based on DC bus coupling according to claim 5 is characterized in that: The step of setting the DC energy storage system to discharge or connect to the mains power grid according to the fourth power information is specifically: Calculating a difference between the fourth power information and the third power to obtain second power difference information; Acquire first power information; Determining whether the first power information exceeds a preset first power threshold; If not, connecting to the mains power grid to transmit electric energy to the energy storage bidirectional converter; If yes, determining first current information according to the first power information and the second power difference information; The output current of the DC energy storage system is set according to the first current information to output electric energy to the energy storage bidirectional converter.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer-readable storage medium includes a photovoltaic storage control method program based on DC bus coupling. When the photovoltaic storage control method program based on DC bus coupling is executed by a processor, the steps of the photovoltaic storage control method based on DC bus coupling as described in any one of claims 1 to 4 are implemented.

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