An off-grid power supply system and control method thereof

Abstract

The off-grid power supply system and control method provided by the present invention are applied to the field of power supply technology. After obtaining the first target parameter and the second target parameter, the method determines the target control strategy from multiple preset control strategies according to the first target parameter and the second target parameter, and finally controls the operation of the off-grid power supply system according to the target control strategy. The method provided by the present invention provides multiple preset control strategies for the off-grid power supply system, and each preset control strategy defines the power supply priority of each subsystem in the off-grid power supply system, which can meet the different power supply requirements of the off-grid power supply system, and more accurately control the operation of the off-grid power supply system, thereby solving the problem of lack of control methods in the prior art and promoting the popularization and application of the off-grid power supply system.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to an off-grid power supply system and a control method thereof. Background Art

[0002] In areas such as plateaus, mountains and isolated islands where it is difficult to build national main power grids, power supply systems based on new energy power generation systems, energy storage systems and other technologies have become the first choice for power supply. Since this type of power supply system does not establish an electrical connection with the national main power grid, it is called an off-grid power supply system.

[0003] Most off-grid power supply systems generate electricity based on new energy modes such as photovoltaics or wind power, and cooperate with energy storage systems, hydrogen production systems, and even electric vehicle charging systems to realize an independent power supply network. They provide stable power supply for the above-mentioned areas where it is difficult to build a national backbone power grid, and play an important role in actual production and life.

[0004] However, since the construction of off-grid power supply systems is not yet mature and there is a lack of effective operation and control methods, it is not conducive to the promotion and application of off-grid power supply systems. Summary of the invention

[0005] The present invention provides an off-grid power supply system and a control method thereof, which solve the problems of immature system construction and lack of operation control method in the prior art, and promote the popularization and application of the off-grid power supply system.

[0006] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides an off-grid power supply system control method, which is applied to an off-grid power supply system including a plurality of subsystems, wherein the plurality of subsystems include a first energy storage system and a second energy storage system, and the method comprises:

[0008] Obtaining a first target parameter and a second target parameter;

[0009] Wherein, the first target parameter represents the operating state of the first energy storage system, and the second target parameter represents the operating state of the second energy storage system;

[0010] Determining a target control strategy from a plurality of preset control strategies according to the first target parameter and the second target parameter;

[0011] Wherein, the preset control strategy includes the power supply priority of each subsystem in the off-grid power supply system;

[0012] The operation of the off-grid power supply system is controlled according to the target control strategy.

[0013] Optionally, the first target parameter includes a battery status value of the first energy storage system, and the second target parameter includes a battery status value of the second energy storage system;

[0014] The multiple preset control strategies include an overcharge control strategy, an undercharge control strategy and a balance control strategy;

[0015] Determining a target control strategy from a plurality of preset control strategies according to the first target parameter and the second target parameter includes:

[0016] If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than a first battery status threshold, determining that the overcharge control strategy is a target control strategy;

[0017] If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both less than a second battery status threshold, determining the undercharge control strategy as the target control strategy;

[0018] If at least one of the battery status value of the first energy storage system and the battery status value of the second energy storage system is greater than or equal to the second battery status threshold and less than or equal to the first battery status threshold, the balancing control strategy is determined to be the target control strategy.

[0019] Optionally, the multiple subsystems further include a hydrogen production system;

[0020] In the case where the overcharge control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes:

[0021] Obtaining the total power generation and total power consumption of the off-grid power supply system;

[0022] If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system and the second energy storage system is controlled in descending order of priority;

[0023] Among them, the priority of the hydrogen production system is higher than the priority of the first energy storage system, and the priority of the first energy storage system is higher than the priority of the second energy storage system.

[0024] Optionally, the process of controlling the power supply of the hydrogen production system, the first energy storage system, and the second energy storage system in order of priority from high to low includes:

[0025] Determining whether the hydrogen production power of the hydrogen production system can be increased;

[0026] If the hydrogen production power can be increased, increase the hydrogen production power and reduce the charging power of the first energy storage system and the second energy storage system;

[0027] If the hydrogen production power cannot be increased, the charging power of the first energy storage system or the second energy storage system is increased.

[0028] Optionally, the determining whether the hydrogen production power of the hydrogen production system can be increased includes:

[0029] If at least one of the battery status value of the first energy storage system and the battery status value of the second energy storage system is less than a third battery status threshold,

[0030] and the hydrogen reserve of the hydrogen production system is less than a first hydrogen reserve threshold,

[0031] and the current hydrogen production power of the hydrogen production system is less than a hydrogen production power threshold, and it is determined that the hydrogen production power of the hydrogen production system can be increased;

[0032] If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold,

[0033] Alternatively, the hydrogen reserve is greater than or equal to the first hydrogen reserve threshold,

[0034] Alternatively, the current hydrogen production power is greater than or equal to the hydrogen production power threshold, and it is determined that the hydrogen production power of the hydrogen production system cannot be increased;

[0035] Wherein, the third battery status threshold is greater than the first battery status threshold.

[0036] Optionally, increasing the hydrogen production power and reducing the charging power of the first energy storage system and the second energy storage system includes:

[0037] The hydrogen production power is increased and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system drops to zero.

[0038] Optionally, the multiple subsystems further include a power generation system, and the method further includes:

[0039] When the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold, reducing the power generation power of the power generation system;

[0040] When the hydrogen reserve is greater than or equal to the first hydrogen reserve threshold, the hydrogen production system is controlled to stop operating.

[0041] Optionally, increasing the charging power of the first energy storage system or the second energy storage system includes:

[0042] Determining whether the charging power of the first energy storage system can be increased;

[0043] If the charging power of the first energy storage system can be increased, increase the charging power of the first energy storage system and reduce the charging power of the second energy storage system;

[0044] If the charging power of the first energy storage system cannot be increased, determining whether the charging power of the second energy storage system can be increased;

[0045] If the charging power of the second energy storage system can be increased, the charging power of the second energy storage system is increased.

[0046] Optionally, the determining whether the charging power of the first energy storage system can be increased includes:

[0047] If the battery status value of the first energy storage system is less than the third battery status threshold, and the current charging power of the first energy storage system is less than the charging power threshold, it is determined that the charging power of the first energy storage system can be increased;

[0048] If the battery status value of the first energy storage system is greater than or equal to the third battery status threshold, or the current charging power of the first energy storage system is greater than or equal to the charging power threshold, it is determined that the charging power of the first energy storage system cannot be increased.

[0049] Optionally, the multiple subsystems further include a hydrogen production system;

[0050] In the case where the balancing control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes:

[0051] Obtaining the total power generation and total power consumption of the off-grid power supply system;

[0052] If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system and the second energy storage system is controlled in descending order of priority;

[0053] Among them, the priority of the hydrogen production system is higher than the priorities of the first energy storage system and the second energy storage system, and the priorities of the first energy storage system and the second energy storage system are the same.

[0054] Optionally, the process of controlling the power supply of the hydrogen production system, the first energy storage system, and the second energy storage system in order of priority from high to low includes:

[0055] Determining whether the hydrogen production power of the hydrogen production system can be increased;

[0056] If the hydrogen production power can be increased, increase the hydrogen production power of the hydrogen production system and reduce the charging power of the first energy storage system and the second energy storage system;

[0057] If the hydrogen production power cannot be increased, the first energy storage system and the second energy storage system are controlled to be charged alternately according to a preset charging interval.

[0058] Optionally, the determining whether the hydrogen production power of the hydrogen production system can be increased includes:

[0059] If the hydrogen reserve of the hydrogen production system is less than a second hydrogen reserve threshold and the current hydrogen production power of the hydrogen production system is less than a hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system can be increased;

[0060] If the hydrogen reserve of the hydrogen production system is greater than or equal to a first hydrogen reserve threshold or the current hydrogen production power of the hydrogen production system reaches the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system cannot be increased;

[0061] The second hydrogen storage threshold is smaller than the first hydrogen storage threshold.

[0062] Optionally, increasing the hydrogen production power of the hydrogen production system and reducing the charging power of the first energy storage system and the second energy storage system includes:

[0063] The hydrogen production power of the hydrogen production system is increased and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system drops to zero.

[0064] Optionally, controlling the first energy storage system and the second energy storage system to charge alternately according to a preset charging interval includes:

[0065] If the hydrogen reserve of the hydrogen production system is greater than or equal to the first hydrogen reserve threshold, the hydrogen production system is controlled to shut down, and the first energy storage system and the second energy storage system are controlled to charge alternately according to a preset charging interval;

[0066] If the hydrogen storage of the hydrogen production system is greater than or equal to the second hydrogen storage threshold and less than the first hydrogen storage threshold, controlling the first energy storage system and the second energy storage system to charge alternately according to a preset charging interval;

[0067] Furthermore, the charging power of the energy storage system in the charging state is the same as the hydrogen production power of the hydrogen production system.

[0068] Optionally, if the total power generation is less than the total power consumption, the hydrogen production power of the hydrogen production system is reduced;

[0069] Controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval;

[0070] If the total power generation is equal to the total power consumption, the current operating state of the off-grid power supply system is maintained.

[0071] Optionally, controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval includes:

[0072] If the hydrogen reserve of the hydrogen production system is greater than a second hydrogen reserve threshold, reducing the hydrogen production power of the hydrogen production system to zero, and controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval;

[0073] If the hydrogen reserve of the hydrogen production system is less than or equal to the second hydrogen reserve threshold and greater than or equal to the third hydrogen reserve threshold, the hydrogen production power of the hydrogen production system is reduced according to a preset ratio, and the first energy storage system and the second energy storage system are controlled to discharge alternately according to a preset discharge interval;

[0074] If the hydrogen reserve of the hydrogen production system is less than the third hydrogen reserve threshold, reducing the discharge power of the first energy storage system and the second energy storage system to zero, and reducing the hydrogen production power of the hydrogen production system;

[0075] The third hydrogen storage threshold is smaller than the second hydrogen storage threshold, and the preset ratio is greater than zero.

[0076] Optionally, the multiple subsystems further include a hydrogen production system and a charging system;

[0077] In the case where the undercharging control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes:

[0078] Obtaining the total power generation and total power consumption of the off-grid power supply system;

[0079] If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system, the second energy storage system and the charging system is controlled in descending order of priority;

[0080] Among them, the priority of the first energy storage system and the second energy storage system is higher than the priority of the hydrogen production system, and the priority of the hydrogen production system is higher than the priority of the charging system.

[0081] Optionally, the process of controlling the power supply of the hydrogen production system, the first energy storage system, the second energy storage system, and the charging system in order of priority from high to low includes:

[0082] If the hydrogen reserve of the hydrogen production system is greater than or equal to a third hydrogen reserve threshold, controlling the charging system to shut down;

[0083] reducing the hydrogen production power of the hydrogen production system;

[0084] If the hydrogen storage amount of the hydrogen production system is less than the third hydrogen storage amount threshold, and the battery status value of the first energy storage system and the battery status value of the second energy storage system are both less than a fourth battery status threshold, the hydrogen production system and the charging system are controlled to shut down;

[0085] The first energy storage system and the second energy storage system are charged according to the total generated power.

[0086] In a second aspect, the present invention provides an off-grid power supply system, including: a power generation system, a hydrogen production system, a charging system, a first energy storage system, a second energy storage system, a DC bus, an AC bus and a controller, wherein:

[0087] The output end of the power generation system is connected to the DC bus;

[0088] The DC input end of the hydrogen production system, the DC connection end of the first energy storage system, and the DC connection end of the second energy storage system are respectively connected to the DC bus;

[0089] The AC connection end of the first energy storage system is connected to the AC bus;

[0090] The AC input end of the hydrogen production system and the charging system are respectively connected to the AC bus;

[0091] The controller is respectively connected to the power generation system, the hydrogen production system, the charging system, the first energy storage system, and the second energy storage system;

[0092] The controller executes the off-grid power supply system control method described in any one of the first aspects of the present invention.

[0093] Optionally, the power generation system includes a photovoltaic power generation system.

[0094] The off-grid power supply system control method provided by the present invention, after obtaining the first target parameter and the second target parameter, determines the target control strategy from multiple preset control strategies according to the first target parameter and the second target parameter, and finally controls the operation of the off-grid power supply system according to the target control strategy. The method provided by the present invention provides multiple preset control strategies for the off-grid power supply system, and each preset control strategy defines the power supply priority of each subsystem in the off-grid power supply system, which can meet the different power supply requirements of the off-grid power supply system, and more accurately control the operation of the off-grid power supply system, thereby solving the problem of lack of control methods in the prior art and promoting the popularization and application of off-grid power supply systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0096] Figure 1 is a structural block diagram of an off-grid power supply system provided by an embodiment of the present invention;

[0097] Figure 2 is a flow chart of an off-grid power supply system control method provided by an embodiment of the present invention;

[0098] Figure 3 is a flow chart of another off-grid power supply system control method provided by an embodiment of the present invention;

[0099] Figure 4 is a flow chart of another off-grid power supply system control method provided by an embodiment of the present invention;

[0100] Figure 5 is a flow chart of another off-grid power supply system control method provided by an embodiment of the present invention;

[0101] Figure 6 It is a flow chart of another off-grid power supply system control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0102] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0103] See also Figure 1 , Figure 1 is a structural block diagram of an off-grid power supply system provided by an embodiment of the present invention. The off-grid power supply system provided by this embodiment includes: a power generation system, a hydrogen production system, a charging system, a first energy storage system, a second energy storage system, a DC bus, an AC bus and a controller (not shown in the figure), wherein:

[0104] The output end of the power generation system is connected to the DC bus. As the main source of power for the off-grid power supply system, in practical applications, the power generation system can use a photovoltaic power generation system. Of course, other power generation systems that can be independent of the national main power grid and supply power independently can also be used. After generating electricity, the power generation system directly outputs it to the DC bus.

[0105] The DC input end of the hydrogen production system, the DC connection end of the first energy storage system, and the DC connection end of the second energy storage system are respectively connected to the DC bus, wherein the hydrogen production system can directly draw power from the DC bus to perform hydrogen production operations, and the first energy storage system and the second energy storage system can draw power from the DC bus to perform charging operations, and can also output electric energy to the DC bus to supplement the power supply shortage of the power generation system. At the same time, the AC connection end of the first energy storage system is also connected to the AC bus to output electric energy to the AC bus. Further, combined with the subsequent content, it can be seen that in the off-grid power supply system provided in this embodiment, the first energy storage system is mainly used for power supply, and the second energy storage system is mainly used to stabilize the bus voltage.

[0106] The AC input terminal and charging system of the hydrogen production system are connected to the AC busbar respectively. It should be noted that the AC power received by the AC input terminal of the hydrogen production system is not used for hydrogen production operations, but is mainly used for the operation of auxiliary systems of the hydrogen production system, such as cooling water circulation, air compressor operation, and power supply of AC distribution cabinets and other equipment.

[0107] It can be imagined that in order to obtain electrical energy to meet its own operating requirements, each constituent system must be equipped with corresponding power conversion devices, such as DC / DC converters, DC / AC converters, etc., which are not listed one by one in this embodiment and can be implemented in combination with existing technologies in actual applications.

[0108] The controller is respectively connected to the power generation system, the hydrogen production system, the charging system, the first energy storage system and the second energy storage system. The controller executes the off-grid power supply system control method provided in the following embodiments of the present invention to control the operation process of the off-grid power supply system.

[0109] Based on the basic structure of the off-grid power supply system described above, an embodiment of the present invention provides a control method for the off-grid power supply system. The control method can be applied to a controller in the system. In some cases, it can also be applied to a server that is set on the network side and can control the operation process of each component system in the off-grid power supply system. Figure 2 , the process of an off-grid power supply system control method provided in this embodiment includes:

[0110] S100: Obtain a first target parameter and a second target parameter.

[0111] Specifically, in this embodiment, the first target parameter is used to characterize the operating state of the first energy storage system, and correspondingly, the second target parameter is used to characterize the operating state of the second energy storage system. Optionally, the first target parameter may be a battery status value of the first energy storage system, and the second target parameter may be a battery status value of the second energy storage system. Through the battery status value, the remaining power of the corresponding energy storage system can be intuitively obtained, and then the working mode of the first energy storage system and the second energy storage system can be determined based on the battery status value. The specific process will be expanded in the subsequent content and will not be described in detail here.

[0112] For the battery status value, the SOC value or the SOH value may be selected, and it can be flexibly selected according to the specific control process, which also falls within the scope of protection of the present invention.

[0113] S110. Determine a target control strategy from a plurality of preset control strategies according to the first target parameter and the second target parameter.

[0114] In order to facilitate the control of the operation process of the off-grid power supply system, the present method provides a variety of preset control strategies, mainly including overcharge control strategy, undercharge control strategy and balance control strategy. Any preset control strategy defines the power supply priority of each subsystem in the off-grid power supply system. It can be imagined that the subsystems described in this embodiment and subsequent embodiments mainly include Figure 1 The power generation system, hydrogen production system, first energy storage system, second energy storage system and charging system shown in.

[0115] Optionally, when the first target parameter is the battery status value of the first energy storage system and the second target parameter is the battery status value of the second energy storage system, the preset control strategy is selected based on the size relationship between the battery status value and the preset battery status threshold. It is conceivable that if the battery status value is the SOC value, the battery status threshold is the SOC threshold, and correspondingly, if the battery status value is the SOH value, the battery status threshold is the SOH threshold.

[0116] Specifically, taking the selection of SOC value as an example, if the SOC value of the first energy storage system and the SOC value of the second energy storage system are both greater than the first SOC threshold, the overcharge control strategy is determined as the target control strategy. In practical applications, the first SOC threshold can be set larger, such as 70%. In this case, the first energy storage system and the second energy storage system have sufficient power, and charging the energy storage system is naturally not a priority issue. This embodiment defines the control strategy in this case as an overcharge control strategy.

[0117] If the SOC value of the first energy storage system and the SOC value of the second energy storage system are both less than the second SOC threshold, the undercharge control strategy is determined to be the target control strategy. In contrast to the overcharge control strategy, in actual applications, the second SOC threshold is set to be relatively small, such as 30%. In this case, the remaining power of the first energy storage system and the second energy storage system is not too high, and priority can be given to charging the first energy storage system and the second energy storage system. This embodiment defines the control strategy in this case as the undercharge control strategy.

[0118] Finally, if at least one of the SOC value of the first energy storage system and the SOC value of the second energy storage system is greater than or equal to the second SOC threshold and less than or equal to the first SOC threshold, the balancing control strategy is determined to be the target control strategy, and it is necessary to control it in combination with the specific conditions of each subsystem in the power supply system. This embodiment defines the control strategy in this case as a balancing control strategy.

[0119] It should be noted that the specific settings of the first battery status threshold and the second battery status threshold can be set in combination with specific control requirements and the actual situation of the energy storage system, and the present invention does not make specific limitations on this.

[0120] S120. Control the operation of the off-grid power supply system according to the target control strategy.

[0121] After the target control strategy is determined, the operation of the power supply system can be controlled according to the power supply priority of each subsystem defined in the target control strategy.

[0122] To sum up, the off-grid power supply system control method provided in the embodiment of the present invention provides multiple preset control strategies for the off-grid power supply system, and each preset control strategy defines the power supply priority of each subsystem in the off-grid power supply system, which can meet the different power supply requirements of the off-grid power supply system, and more accurately control the operation of the off-grid power supply system, thereby solving the problem of lack of control methods in the prior art and promoting the popularization and application of off-grid power supply systems.

[0123] The following describes the specific process of controlling the operation of the off-grid power supply system according to the target control strategy for different preset control strategies.

[0124] When the overcharge control strategy is the target control strategy, the process of controlling the operation of the off-grid power supply system can refer to Figure 3 Implementation shown.

[0125] S200: Obtain the total power generation and total power consumption of the off-grid power supply system.

[0126] In practical applications, the total power generation of the off-grid power supply system refers to the total power output by the power generation system in the off-grid power supply system. Although the first energy storage system and the second energy storage system can also output power to supply the power load, the electric energy of both also needs to be provided by the power generation system. Therefore, the total power generation of the off-grid power supply system does not include the output power of the first energy storage system and the second energy storage system.

[0127] Accordingly, the total power consumption includes the systems and equipment that consume power in the off-grid power supply system, such as Figure 1 As shown, the power consumption includes the hydrogen production system, the first energy storage system, the second energy storage system and the charging system.

[0128] S210, determine whether the total power generation is greater than the total power consumption, if so, execute S220.

[0129] If the total power generation of the off-grid power supply system is greater than the total power consumption, S220 and subsequent steps are executed to control the power supply process of the hydrogen production system, the first energy storage system, and the second energy storage system in order of priority from high to low. Furthermore, in this embodiment, the priority of the hydrogen production system is higher than the priority of the first energy storage system, and the priority of the first energy storage system is higher than the priority of the second energy storage system; on the contrary, if the total power generation of the off-grid power generation system is less than or equal to the total power consumption, the current operating state of the system is maintained.

[0130] S220, determine whether the hydrogen production power of the hydrogen production system can be increased, if so, execute S230, if not, execute S240.

[0131] When the total power generation of the off-grid power supply system is greater than the total power consumption, it is further determined whether the hydrogen production power of the hydrogen production system can be increased. If so, S230 is executed; if not, S240 is executed.

[0132] Optionally, whether the hydrogen production power of the hydrogen production system can be increased can be determined according to the following criteria:

[0133] If at least one of the battery status value of the first energy storage system and the battery status value of the second energy storage system is less than a third battery status threshold, and the hydrogen reserve of the hydrogen production system is less than the first hydrogen reserve threshold, and the current hydrogen production power of the hydrogen production system is less than the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system can be increased;

[0134] On the contrary, if the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold, or the hydrogen reserves are greater than or equal to the first hydrogen reserves threshold, or the current hydrogen production power is greater than or equal to the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system cannot be increased.

[0135] Among them, the third battery state threshold in the above judgment standard is greater than the first battery state threshold described in the above embodiment. In practical applications, a higher value can be selected. Still taking the SOC value as an example, it can be set to 98%. Of course, if you want to reserve more safety space for the energy storage system, you can also lower the selection of the third SOC threshold accordingly, such as setting it to 90%. The main purpose of setting the third SOC threshold is to determine whether the energy storage system is at or close to full capacity and can absorb more electric power. Under this premise, the third SOC threshold selected in combination with the actual operation of the energy storage system is optional. The present invention does not specifically limit the specific value of the third SOC threshold.

[0136] Furthermore, the first hydrogen reserve threshold should be a larger value to measure or limit whether further hydrogen production operations can be carried out. For example, 98% of the total capacity of the hydrogen storage device can be taken as the first hydrogen reserve threshold. Correspondingly, the hydrogen production power threshold can be determined based on the maximum hydrogen production power or rated hydrogen production power threshold of the hydrogen production system to measure whether the hydrogen production power can be further increased. The present invention does not limit the specific values ​​of the first hydrogen reserve threshold and the hydrogen production power threshold.

[0137] S230, increasing the hydrogen production power and reducing the charging power of the first energy storage system and the second energy storage system.

[0138] Optionally, after the above judgment, if it is determined that the hydrogen production power still has room for increase, the hydrogen production power is further increased, and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the aforementioned hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system is reduced to zero, that is, all power is used for hydrogen production, thereby achieving the purpose of using electrical energy for hydrogen production as much as possible and improving hydrogen production efficiency. Of course, this also further illustrates that in this embodiment, the power supply priority of the hydrogen production system is higher than that of the first energy storage system and the second energy storage system.

[0139] S240: Increase the charging power of the first energy storage system or the second energy storage system.

[0140] If the hydrogen production power cannot be further increased, the charging power of the first energy storage system or the second energy storage system is increased to store as much electric energy as possible from the power generation system for use when the subsequent power generation system cannot provide sufficient electric energy.

[0141] Optional, see Figure 4 , Figure 4 The flowchart shown shows an optional implementation process of this step.

[0142] S300, determining whether the charging power of the first energy storage system can be increased, if so, executing S310, if not, executing S320.

[0143] Optionally, if the battery status value of the first energy storage system is less than the aforementioned third battery status threshold, that is, there is a possibility of further storing electrical energy, and the current charging power of the first energy storage system is less than the charging power threshold, that is, the charging power can be further increased, then it is determined that the charging power of the first energy storage system can be increased; on the contrary, if the battery status value of the first energy storage system is greater than or equal to the third battery status threshold, or the current charging power of the first energy storage system is greater than or equal to the charging power threshold, it is determined that the charging power of the first energy storage system cannot be increased.

[0144] Similar to the threshold setting involved in the aforementioned content, the setting of the charging power threshold is subject to the specific energy storage system adopted, and the present invention does not limit the specific setting of the charging power threshold.

[0145] S310: Increase the charging power of the first energy storage system and reduce the charging power of the second energy storage system.

[0146] When it is determined that the charging power of the first energy storage system can be further increased, the charging power of the first energy storage system can be increased, while the charging power of the second energy storage system can be reduced, so as to give priority to ensuring the energy storage of the first energy storage system until the charging power of the first energy storage system reaches the aforementioned charging power threshold or the charging power of the second energy storage system drops to zero, so that the first energy storage system is charged at the maximum charging power.

[0147] S320: Determine whether the charging power of the second energy storage system can be increased. If so, execute S330.

[0148] If it is determined in S300 that the charging power of the first energy storage system cannot be further increased, it is further determined whether the charging power of the second energy storage system can be increased. Specifically, the judgment logic of this step is similar to the judgment logic of S300, that is, if the battery status value of the second energy storage system is less than the aforementioned third battery status threshold, and the current charging power of the second energy storage system is less than the charging power threshold, it is determined that the charging power of the second energy storage system can be increased; on the contrary, if the battery status value of the second energy storage system is greater than or equal to the third battery status threshold, or the current charging power of the second energy storage system is greater than or equal to the charging power threshold, it is determined that the charging power of the second energy storage system cannot be increased.

[0149] It should be noted that, after screening by the aforementioned judgment logic, when executing this step, if it is determined that the charging power of the second energy storage system cannot be further increased, that is, the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold, it means that the output power of the power generation system can no longer be further absorbed. In this case, the output power of the power generation system should be reduced to ensure stable operation of the system.

[0150] Correspondingly, if the hydrogen reserve of the hydrogen production system is greater than or equal to the first hydrogen reserve threshold, the hydrogen production system is controlled to stop running.

[0151] S330: Increase the charging power of the second energy storage system.

[0152] It is conceivable that, in the process of increasing the charging power of the second energy storage system, if the charging power of the second energy storage system reaches the aforementioned charging power threshold, the increase in the charging power of the second energy storage system can be stopped.

[0153] In summary, when the overcharging control strategy is adopted, the hydrogen production system has the highest priority, the first energy storage system has the second priority, and the second energy storage system has the lowest priority. The operation of the off-grid power supply system is controlled in order of priority from high to low, and electric energy is used for hydrogen production first, which helps to improve the utilization rate of electric energy.

[0154] When the balance control strategy is the target control strategy, the process of controlling the operation of the off-grid power supply system can refer to Figure 5 Implementation shown.

[0155] S400: Obtain the total power generation and total power consumption of the off-grid power supply system.

[0156] Optionally, the optional implementation of S400 can refer to Figure 3 The corresponding contents in S200 in the illustrated embodiment will not be repeated here.

[0157] S410, determine whether the total power generation is greater than the total power consumption, if so, execute S420, if not, execute S450.

[0158] Optionally, the optional implementation of S410 can refer to Figure 3 The corresponding content in S210 in the illustrated embodiment is not further described here.

[0159] S420, determine whether the hydrogen production power of the hydrogen production system can be increased, if so, execute S430, if not, execute S440.

[0160] Optionally, if the hydrogen reserves of the hydrogen production system are less than a second hydrogen reserves threshold and the current hydrogen production power of the hydrogen production system is less than the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system can be increased; on the contrary, if the hydrogen reserves of the hydrogen production system are greater than or equal to the first hydrogen reserves threshold or the current hydrogen production power of the hydrogen production system reaches the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system cannot be increased.

[0161] It should be noted that the second hydrogen reserve threshold described in this embodiment is less than the first hydrogen reserve threshold described in the aforementioned embodiment. For example, 70% of the total amount of hydrogen that can be stored in the hydrogen production system can be used as the second hydrogen reserve threshold. As for the hydrogen production power threshold, it needs to be set in combination with the specific parameters of the hydrogen production system. The present invention does not limit the specific values ​​of the first hydrogen reserve threshold and the hydrogen production power threshold.

[0162] S430: Increase the hydrogen production power of the hydrogen production system and reduce the charging power of the first energy storage system and the second energy storage system.

[0163] When it is determined that the hydrogen production power of the hydrogen production system can be increased, the hydrogen production power of the hydrogen production system is increased, and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system is reduced to zero, that is, the electricity consumption of the hydrogen production system is prioritized, with the normal operation of the hydrogen production system as the highest priority.

[0164] S440, controlling the first energy storage system and the second energy storage system to charge alternately according to a preset charging interval.

[0165] If it is determined in S420 that the hydrogen production power of the hydrogen production system cannot be further increased, the first energy storage system and the second energy storage system are controlled to be charged alternately according to a preset charging interval.

[0166] Specifically, further judgment can be made based on the hydrogen reserves of the hydrogen production system. If the hydrogen reserves of the hydrogen production system are greater than or equal to the aforementioned first hydrogen reserves threshold, it can be determined that the hydrogen reserves are close to saturation. At this time, the hydrogen production system can be controlled to shut down, and the first energy storage system and the second energy storage system can be controlled to charge alternately according to the preset charging interval; correspondingly, if the hydrogen reserves of the hydrogen production system are greater than or equal to the second hydrogen reserves threshold and less than the first hydrogen reserves threshold, the current hydrogen production power of the hydrogen production system is maintained, and hydrogen production continues. At the same time, the first energy storage system and the second energy storage system are controlled to charge alternately according to the preset charging interval, and the charging power of the energy storage system in the charging state (which can be the first energy storage system or the second energy storage system) is the same as the hydrogen production power of the hydrogen production system.

[0167] Optionally, in this step, the first energy storage system and the second energy storage system are controlled to be charged alternately according to a preset charging interval, and any one of the first energy storage system and the second energy storage system can be selected as the target energy storage system. The target energy storage system is first controlled to charge according to the preset charging interval. After the charging time reaches the preset charging interval, the charging of the target energy storage system is stopped, and the other energy storage system other than the target energy storage system is charged according to the preset charging interval. This process is repeated alternately to charge the first energy storage system and the second energy storage system respectively.

[0168] S450: When the total power generation is less than the total power consumption, the hydrogen production power of the hydrogen production system is reduced.

[0169] If the total power generation of the power generation system is less than the total power consumption, in order to ensure the stability of the entire system, it is necessary to reduce the hydrogen production power of the hydrogen production system, and give priority to reducing the consumption of electricity by the hydrogen production system so that more electric power can be used to supply the power load, thereby ensuring the normal operation of the power load.

[0170] S460, controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval.

[0171] In order to more finely control the discharge process of the first energy storage system and the second energy storage system, this embodiment further provides a second hydrogen storage threshold and a third hydrogen storage threshold on the basis of the aforementioned first hydrogen storage threshold, and the second hydrogen storage threshold is less than the aforementioned first hydrogen storage threshold, and the third hydrogen storage threshold is less than the second hydrogen storage threshold. For example, the second hydrogen storage threshold may be 70% of the total reserves, and the third hydrogen storage threshold may be 30% of the total reserves.

[0172] On this basis, it is further determined whether the hydrogen reserves of the hydrogen production system are greater than the second hydrogen reserves threshold. If the hydrogen reserves of the hydrogen production system are greater than the second hydrogen reserves threshold, the hydrogen production power of the hydrogen production system is directly reduced to zero, and the first energy storage system and the second energy storage system are controlled to discharge alternately according to the preset discharge interval.

[0173] If the hydrogen reserves of the hydrogen production system are less than or equal to the second hydrogen reserves threshold and greater than or equal to the third hydrogen reserves threshold, the hydrogen production power of the hydrogen production system is reduced according to a preset ratio, that is, it is not directly reduced to zero, but hydrogen production is continued at a relatively small hydrogen production power, and at the same time, the first energy storage system and the second energy storage system are controlled to discharge alternately according to a preset discharge interval.

[0174] Furthermore, if the hydrogen reserves of the hydrogen production system are less than a third hydrogen reserves threshold, the discharge power of the first energy storage system and the second energy storage system is reduced to zero, and the hydrogen production power of the hydrogen production system is reduced.

[0175] It should be noted that the process of controlling the first energy storage system and the second energy storage system to discharge alternately according to the preset discharge interval in this embodiment is similar to the process of controlling the first energy storage system and the second energy storage system to charge alternately according to the preset charging interval. Specifically, any one of the first energy storage system and the second energy storage system can be selected as the target energy storage system, and the target energy storage system is first controlled to discharge according to the preset discharge interval. After the discharge time reaches the preset discharge interval, the target energy storage system is stopped from being discharged, and the other energy storage system other than the target energy storage system is discharged according to the preset discharge interval. This process is repeated alternately to discharge the first energy storage system and the second energy storage system respectively.

[0176] Optionally, if the total power generated by the power generation system is equal to the total power consumed, the current operating state of the off-grid power supply system is maintained.

[0177] In summary, when the balancing control strategy is used to control the off-grid power supply system, it is also necessary to control the power supply process of the hydrogen production system, the first energy storage system and the second energy storage system in order of priority from high to low. Specifically, in the balancing control strategy, the priority of the hydrogen production system is higher than that of the first energy storage system and the second energy storage system, and the first energy storage system and the second energy storage system have the same priority, and the first energy storage system and the second energy storage system can be charged and discharged at the same time.

[0178] When the under-charging control strategy is the target control strategy, the process of controlling the operation of the off-grid power supply system can refer to Figure 6 Implementation shown.

[0179] S500: Obtain the total power generation and total power consumption of the off-grid power supply system.

[0180] Optional, the optional implementation of S500 can refer to Figure 3 The corresponding contents in S200 in the illustrated embodiment will not be repeated here.

[0181] S510, determine whether the total power generation is greater than the total power consumption, if so, execute S520.

[0182] Optionally, the optional implementation of S510 can refer to Figure 3 The corresponding content in S210 in the illustrated embodiment is not further described here.

[0183] If the total power generation is equal to the total power consumption, no further processing is required and the system can be maintained in its current operating state. If the total power generation is less than the total power consumption, the power load of the power load should be reduced. It should be noted that since the hydrogen production load is a special power load, in the process of reducing the power load, the hydrogen production power should be reduced first, that is, the hydrogen production load should be reduced, and then other power loads connected to the system should be gradually reduced.

[0184] S520, determining whether the hydrogen reserve of the hydrogen production system is greater than or equal to a third hydrogen reserve threshold, if not, executing S530, and if so, executing S540.

[0185] S530, controlling the charging system to shut down and reducing the hydrogen production power of the hydrogen production system.

[0186] When the hydrogen reserves of the hydrogen production system are less than the third hydrogen reserves threshold, the charging system is preferentially shut down to reduce the total amount of electric power consumption. At the same time, the hydrogen production power of the hydrogen production system is gradually reduced until the hydrogen production power is reduced to zero.

[0187] S540, determine whether the battery status value of the first energy storage system and the battery status value of the second energy storage system are both less than a fourth battery status threshold, and if so, execute S550.

[0188] When the hydrogen storage of the hydrogen production system is greater than or equal to the third hydrogen storage threshold, the relationship between the battery status value of the first energy storage system and the battery status value of the second energy storage system and the fourth battery status threshold is further determined. It should be noted that in this embodiment, the fourth battery status threshold needs to be a smaller value, which is smaller than any of the aforementioned battery status thresholds, for example, 2%. If the battery status value of the energy storage system is less than the fourth battery status threshold, it means that the power of the energy storage system is very low and charging continues.

[0189] If the battery status value of at least one of the first energy storage system and the second energy storage system is greater than a fourth battery status threshold, the discharge power of the energy storage system whose battery status value is greater than the fourth battery status threshold is increased.

[0190] S550, controlling the hydrogen production system and the charging system to shut down, and charging the first energy storage system and the second energy storage system according to the total power generation.

[0191] When the hydrogen reserves of the hydrogen production system are greater than or equal to the third hydrogen reserves threshold, and the battery status values ​​of the first energy storage system and the second energy storage system are both less than the fourth battery status threshold, the hydrogen production system and the charging system are controlled to shut down, and the first energy storage system and the second energy storage system are charged according to the total power generation, that is, all the power of the power generation system is used to charge the energy storage system.

[0192] From the above control process, it can be seen that in the undercharging control strategy, although the power supply process of the hydrogen production system, the first energy storage system, the second energy storage system and the charging system is also controlled in order of priority from high to low, however, unlike the aforementioned embodiment, in this embodiment, the priority of the first energy storage system and the second energy storage system is higher than that of the hydrogen production system, and the priority of the hydrogen production system is higher than that of the charging system.

[0193] It can be seen from the control methods provided in the above-mentioned embodiments that the control method provided by the present invention for an off-grid power supply system including two energy storage systems can not only meet the different power supply requirements of the off-grid power supply system, but also more accurately control the operation of the off-grid power supply system, thereby solving the problem of lack of control methods in the prior art. Furthermore, by separately controlling the first energy storage system and the second energy storage system, the first energy storage system and the second energy storage system play different functions. The first energy storage system is mainly used to supply power to the electrical load, so in the process of charging and discharging control, the priority of the first energy storage system is higher than that of the second energy storage system, while the second energy storage system is mainly used to stabilize the voltage of the DC bus. In the control process, the SOC of the second energy storage system is maintained in a reasonable range, and the output voltage can be stabilized. Therefore, its priority is lower. Through the cooperation of the first energy storage system and the second energy storage system, the operation stability of the off-grid power supply system is effectively improved.

[0194] The various embodiments of the present invention are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0195] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A control method for an off-grid power supply system, characterized in that: The invention is applied to an off-grid power supply system including a plurality of subsystems, and the plurality of subsystems include a power generation system, a hydrogen production system, a charging system, a first energy storage system, and a second energy storage system, wherein the output end of the power generation system, the DC input end of the hydrogen production system, the DC connection end of the first energy storage system, and the DC connection end of the second energy storage system are respectively connected to a DC bus, the first energy storage system and the second energy storage system can both draw power from the DC bus and output electric energy to the DC bus, the AC input end of the charging system, the hydrogen production system, and the AC connection end of the first energy storage system are connected to the AC bus, and the method comprises: Acquire a first target parameter and a second target parameter; wherein the first target parameter represents the operating state of the first energy storage system, and the second target parameter represents the operating state of the second energy storage system; the first target parameter includes a battery status value of the first energy storage system, and the second target parameter includes a battery status value of the second energy storage system; According to the first target parameter and the second target parameter, a target control strategy is determined from a plurality of preset control strategies based on a magnitude relationship between a battery status value and a preset battery status threshold; wherein the plurality of preset control strategies include an overcharge control strategy, an undercharge control strategy, and a balance control strategy, and each of the preset control strategies includes a power supply priority of each subsystem in the off-grid power supply system; The operation of the off-grid power supply system is controlled according to the target control strategy; wherein, when the overcharging control strategy is adopted, the priority of the hydrogen production system is higher than the priority of the first energy storage system, the priority of the first energy storage system is higher than the priority of the second energy storage system, and the operation of the off-grid power supply system is controlled in descending order of priority; when the balancing control strategy is adopted, the priority of the hydrogen production system is higher than the priority of the first energy storage system and the second energy storage system, the first energy storage system and the second energy storage system have the same priority, and the operation of the off-grid power supply system is controlled in descending order of priority; when the undercharging control strategy is adopted, the priority of the first energy storage system and the second energy storage system is higher than the priority of the hydrogen production system, the priority of the hydrogen production system is higher than the priority of the charging system, and the operation of the off-grid power supply system is controlled in descending order of priority.

2. The off-grid power supply system control method according to claim 1, characterized in that: The determining of a target control strategy from a plurality of preset control strategies based on the relationship between the battery state value and a preset battery state threshold value according to the first target parameter and the second target parameter includes: If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than a first battery status threshold, determining that the overcharge control strategy is a target control strategy; If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both less than a second battery status threshold, determining the undercharge control strategy as the target control strategy; If at least one of the battery status value of the first energy storage system and the battery status value of the second energy storage system is greater than or equal to the second battery status threshold and less than or equal to the first battery status threshold, the balancing control strategy is determined to be the target control strategy.

3. The off-grid power supply system control method according to claim 2, characterized in that: In the case where the overcharge control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes: Obtaining the total power generation and total power consumption of the off-grid power supply system; If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system and the second energy storage system is controlled in order of priority from high to low.

4. The off-grid power supply system control method according to claim 3, characterized in that: The process of controlling the power supply of the hydrogen production system, the first energy storage system, and the second energy storage system in order of priority from high to low includes: Determining whether the hydrogen production power of the hydrogen production system can be increased; If the hydrogen production power can be increased, increase the hydrogen production power and reduce the charging power of the first energy storage system and the second energy storage system; If the hydrogen production power cannot be increased, the charging power of the first energy storage system or the second energy storage system is increased.

5. The off-grid power supply system control method according to claim 4, characterized in that: The determining whether the hydrogen production power of the hydrogen production system can be increased includes: If at least one of the battery status value of the first energy storage system and the battery status value of the second energy storage system is less than a third battery status threshold, and the hydrogen reserve of the hydrogen production system is less than a first hydrogen reserve threshold, and the current hydrogen production power of the hydrogen production system is less than a hydrogen production power threshold, and it is determined that the hydrogen production power of the hydrogen production system can be increased; If the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold, Alternatively, the hydrogen reserve is greater than or equal to the first hydrogen reserve threshold, Alternatively, the current hydrogen production power is greater than or equal to the hydrogen production power threshold, and it is determined that the hydrogen production power of the hydrogen production system cannot be increased; Wherein, the third battery status threshold is greater than the first battery status threshold.

6. The off-grid power supply system control method according to claim 5, characterized in that: The increasing the hydrogen production power and reducing the charging power of the first energy storage system and the second energy storage system includes: The hydrogen production power is increased and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system drops to zero.

7. The off-grid power supply system control method according to claim 5, characterized in that: The method further comprises: When the battery status value of the first energy storage system and the battery status value of the second energy storage system are both greater than or equal to the third battery status threshold, reducing the power generation power of the power generation system; When the hydrogen reserve is greater than or equal to the first hydrogen reserve threshold, the hydrogen production system is controlled to stop operating.

8. The off-grid power supply system control method according to claim 5, characterized in that: The increasing the charging power of the first energy storage system or the second energy storage system includes: Determining whether the charging power of the first energy storage system can be increased; If the charging power of the first energy storage system can be increased, increase the charging power of the first energy storage system and reduce the charging power of the second energy storage system; If the charging power of the first energy storage system cannot be increased, determining whether the charging power of the second energy storage system can be increased; If the charging power of the second energy storage system can be increased, the charging power of the second energy storage system is increased.

9. The off-grid power supply system control method according to claim 8, characterized in that: The determining whether the charging power of the first energy storage system can be increased includes: If the battery status value of the first energy storage system is less than the third battery status threshold, and the current charging power of the first energy storage system is less than the charging power threshold, it is determined that the charging power of the first energy storage system can be increased; If the battery status value of the first energy storage system is greater than or equal to the third battery status threshold, or the current charging power of the first energy storage system is greater than or equal to the charging power threshold, it is determined that the charging power of the first energy storage system cannot be increased.

10. The off-grid power supply system control method according to claim 2, characterized in that: In the case where the balancing control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes: Obtaining the total power generation and total power consumption of the off-grid power supply system; If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system and the second energy storage system is controlled in order of priority from high to low.

11. The off-grid power supply system control method according to claim 10, characterized in that: The process of controlling the power supply of the hydrogen production system, the first energy storage system, and the second energy storage system in order of priority from high to low includes: Determining whether the hydrogen production power of the hydrogen production system can be increased; If the hydrogen production power can be increased, increase the hydrogen production power of the hydrogen production system and reduce the charging power of the first energy storage system and the second energy storage system; If the hydrogen production power cannot be increased, the first energy storage system and the second energy storage system are controlled to be charged alternately according to a preset charging interval.

12. The off-grid power supply system control method according to claim 11, characterized in that: The determining whether the hydrogen production power of the hydrogen production system can be increased includes: If the hydrogen reserve of the hydrogen production system is less than a second hydrogen reserve threshold and the current hydrogen production power of the hydrogen production system is less than a hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system can be increased; If the hydrogen reserve of the hydrogen production system is greater than or equal to a first hydrogen reserve threshold or the current hydrogen production power of the hydrogen production system reaches the hydrogen production power threshold, it is determined that the hydrogen production power of the hydrogen production system cannot be increased; The second hydrogen storage threshold is smaller than the first hydrogen storage threshold.

13. The off-grid power supply system control method according to claim 12, characterized in that: The increasing the hydrogen production power of the hydrogen production system and reducing the charging power of the first energy storage system and the second energy storage system includes: The hydrogen production power of the hydrogen production system is increased and the charging power of the first energy storage system and the second energy storage system is reduced until the hydrogen production power reaches the hydrogen production power threshold or the charging power of the first energy storage system and the second energy storage system drops to zero.

14. The off-grid power supply system control method according to claim 12, characterized in that: The step of controlling the first energy storage system and the second energy storage system to charge alternately according to a preset charging interval includes: If the hydrogen reserve of the hydrogen production system is greater than or equal to the first hydrogen reserve threshold, the hydrogen production system is controlled to shut down, and the first energy storage system and the second energy storage system are controlled to charge alternately according to a preset charging interval; If the hydrogen storage of the hydrogen production system is greater than or equal to the second hydrogen storage threshold and less than the first hydrogen storage threshold, controlling the first energy storage system and the second energy storage system to charge alternately according to a preset charging interval; Furthermore, the charging power of the energy storage system in the charging state is the same as the hydrogen production power of the hydrogen production system.

15. The off-grid power supply system control method according to claim 10, characterized in that: If the total power generation is less than the total power consumption, reducing the hydrogen production power of the hydrogen production system; Controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval; If the total power generation is equal to the total power consumption, the current operating state of the off-grid power supply system is maintained.

16. The off-grid power supply system control method according to claim 15, characterized in that: The step of controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval includes: If the hydrogen reserve of the hydrogen production system is greater than a second hydrogen reserve threshold, reducing the hydrogen production power of the hydrogen production system to zero, and controlling the first energy storage system and the second energy storage system to discharge alternately according to a preset discharge interval; If the hydrogen reserve of the hydrogen production system is less than or equal to the second hydrogen reserve threshold and greater than or equal to the third hydrogen reserve threshold, the hydrogen production power of the hydrogen production system is reduced according to a preset ratio, and the first energy storage system and the second energy storage system are controlled to discharge alternately according to a preset discharge interval; If the hydrogen reserve of the hydrogen production system is less than the third hydrogen reserve threshold, reducing the discharge power of the first energy storage system and the second energy storage system to zero, and reducing the hydrogen production power of the hydrogen production system; The third hydrogen storage threshold is smaller than the second hydrogen storage threshold, and the preset ratio is greater than zero.

17. The off-grid power supply system control method according to claim 2, characterized in that: In the case where the undercharging control strategy is a target control strategy, controlling the operation of the off-grid power supply system according to the target control strategy includes: Obtaining the total power generation and total power consumption of the off-grid power supply system; If the total power generation is greater than the total power consumption, the power supply process of the hydrogen production system, the first energy storage system, the second energy storage system and the charging system is controlled in order of priority from high to low.

18. The off-grid power supply system control method according to claim 17, characterized in that: The process of controlling the power supply of the hydrogen production system, the first energy storage system, the second energy storage system and the charging system in order of priority from high to low includes: If the hydrogen reserve of the hydrogen production system is greater than or equal to a third hydrogen reserve threshold, controlling the charging system to shut down; reducing the hydrogen production power of the hydrogen production system; If the hydrogen storage amount of the hydrogen production system is less than the third hydrogen storage amount threshold, and the battery status value of the first energy storage system and the battery status value of the second energy storage system are both less than a fourth battery status threshold, the hydrogen production system and the charging system are controlled to shut down; The first energy storage system and the second energy storage system are charged according to the total generated power.

19. An off-grid power supply system, characterized in that: include: A power generation system, a hydrogen production system, a charging system, a first energy storage system, a second energy storage system, a DC bus, an AC bus and a controller, wherein: The output end of the power generation system is connected to the DC bus; The DC input end of the hydrogen production system, the DC connection end of the first energy storage system, and the DC connection end of the second energy storage system are respectively connected to the DC bus; The AC connection end of the first energy storage system is connected to the AC bus; The AC input end of the hydrogen production system and the charging system are respectively connected to the AC bus; The controller is respectively connected to the power generation system, the hydrogen production system, the charging system, the first energy storage system, and the second energy storage system; The controller executes the off-grid power supply system control method according to any one of claims 1-18.

20. The off-grid power supply system according to claim 19, characterized in that: The power generation system includes a photovoltaic power generation system.

Images