Isolation circuit for hydrogen production system and renewable energy hydrogen production system comprising same

Abstract

The invention provides an isolation circuit for a hydrogen production system and a renewable energy hydrogen production system comprising the same, the isolation circuit comprises at least one DC conversion module and at least one DC-AC converter, and the DC conversion module comprises a single output port and a multi-output port; a single output port of the DC conversion module is coupled with the DC side of the DC-AC converter; a plurality of output ports of the DC conversion module are coupled with a plurality of external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow units at least comprise hydrogen production units; and the AC end of the DC-AC converter is coupled and connected with an external AC power grid or a DC power grid in series. According to the scheme, the application requirements of two coupling situations are met at the same time, various types of external units are effectively fused, all parts in the system are fused into a whole, the cost is reduced, and meanwhile positioning and maintenance of faults are facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen preparation, and in particular to an isolation circuit for a hydrogen production system and a renewable energy hydrogen production system including the isolation circuit. Background Art

[0002] At present, the system design of renewable energy hydrogen production application can be summarized as AC coupling or DC coupling. Whether it is AC coupling or DC coupling, each is designed separately for different functional devices or units in the system. Different devices and units are basically unrelated in design. This method not only leads to high costs in the design of the entire system, but also makes it difficult to expand the system. If a system failure occurs, there are great difficulties in fault identification and repair and recovery. Summary of the invention

[0003] The technical problem to be solved by the present application is that in the existing renewable energy hydrogen production scheme, the high cost, difficulty in expansion and difficulty in fault repair are caused by the inability to design the system as a whole due to the independent design of different equipment or units. Therefore, an isolation circuit for a hydrogen production system and a renewable energy hydrogen production system including the isolation circuit are provided.

[0004] In a first aspect, the technical solution of the present application provides an isolation circuit for a hydrogen production system, comprising:

[0005] At least one DC conversion module, the DC conversion module comprising a single output port and a multi-output port;

[0006] at least one DC-AC converter;

[0007] The single output port of the DC conversion module is coupled and connected to the DC side of the DC-AC converter;

[0008] The multiple output ports of the DC conversion module are coupled to multiple external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow unit at least includes a hydrogen production unit;

[0009] The AC end of the DC-AC converter is coupled to an external AC grid or a DC grid in series.

[0010] In some embodiments, the isolation circuit for a hydrogen production system, the unidirectional power flow unit includes a hybrid hydrogen production unit and / or a new energy power generation unit; the hybrid hydrogen production unit includes two or more hydrogen production modules;

[0011] The bidirectional power flow unit includes an energy storage unit.

[0012] In some embodiments of the isolation circuit for a hydrogen production system, a plurality of the unidirectional power flow units are coupled in parallel to the multiple output ports.

[0013] In some schemes, when the DC conversion module of the isolation circuit for the hydrogen production system is connected to the hybrid hydrogen production unit or the new energy power generation unit, the DC conversion module is configured with an isolation unit.

[0014] In a second aspect, the technical solution of the present application provides a renewable energy hydrogen production system, comprising at least one isolation circuit for a hydrogen production system according to the technical solution of the first aspect, and:

[0015] At least one renewable energy power generation unit, each of the renewable energy power generation units is coupled to an output port of the isolation circuit;

[0016] At least one energy storage unit, the energy storage unit is coupled to an output port of the isolation circuit;

[0017] At least one hydrogen production unit is coupled to an output port of the isolation circuit.

[0018] In some embodiments of the renewable energy hydrogen production system, when the renewable energy power generation unit includes multiple renewable energy power generation units, the multiple renewable energy power generation units are coupled in parallel to the multiple output ports of the isolation circuit.

[0019] In some embodiments of the renewable energy hydrogen production system, when the renewable energy power generation unit comprises a plurality of units, the plurality of renewable energy power generation units are divided into a plurality of parallel coupling groups;

[0020] The renewable energy generation units in each of the parallel coupling groups are coupled to the parallel coupling ports in a parallel manner; and the parallel coupling ports in a plurality of the parallel coupling groups are coupled to the plurality of output ports of the isolation circuit in a parallel manner.

[0021] In some embodiments of the renewable energy hydrogen production system, when the hydrogen production unit includes multiple units, the types of the hydrogen production units include at least two.

[0022] In some embodiments, the renewable energy hydrogen production system comprises a hydrogen production unit including an alkaline hydrogen production module, a solid oxide hydrogen production module and a PEM hydrogen production module.

[0023] In a third aspect, the technical solution of the present application provides a control method for the renewable energy hydrogen production system described in any one of the above items, comprising:

[0024] Determine the system operation mode according to the type of the unidirectional power flow unit and / or the bidirectional power flow unit external to the system;

[0025] If the system operation mode is a new energy basic grid-connected mode: control the power path direction of the isolation circuit to achieve a unidirectional power flow direction of power from a single type of renewable energy power generation unit to an AC or DC bus unit;

[0026] If the system operation mode is the energy storage-based grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve the direction of bidirectional power flow from a single type of energy storage unit to an AC or DC bus unit;

[0027] If the system operating mode is a grid-connected basic hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to the single type of hydrogen production unit.

[0028] The control method of the renewable energy hydrogen production system described in some schemes also includes:

[0029] If the system operation mode is a new energy hybrid grid-connected mode: control the power path direction of the isolation circuit to achieve a unidirectional power flow direction of power from multiple types of renewable energy power generation units to the AC or DC bus unit;

[0030] If the system operation mode is a hybrid energy storage grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve a bidirectional power flow direction from multiple types of energy storage units to the AC or DC bus unit;

[0031] If the system operation mode is a grid-connected hybrid hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to multiple types of hydrogen production units.

[0032] The technical solution of this application has the following technical effects compared with the prior art:

[0033] The present application provides an isolation circuit for a hydrogen production system and a renewable energy hydrogen production system including the same, wherein the isolation circuit includes at least one DC conversion module and at least one DC-AC converter, the DC conversion module includes a single output port and a multi-output port; the single output port of the DC conversion module is coupled and connected to the DC side of the DC-AC converter; the multi-output ports of the DC conversion module are coupled and connected to multiple external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow units at least include a hydrogen production unit; the AC end of the DC-AC converter is coupled and connected in series with an external AC power grid or a DC power grid. Therefore, the present solution has reserved a coupling port for an external AC power grid or a DC power grid, which can be applied to both AC coupling and DC coupling, and meets the application requirements of both coupling situations. In specific use, the port of the unidirectional power flow unit and / or the bidirectional power flow unit is directly connected to the output port of the isolation circuit to complete the coupling connection of the entire system. The above-mentioned scheme of the present application can adopt a simple method to effectively integrate various types of external units, integrate various components in the system into one, reduce costs, and facilitate fault location and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, which will help to understand the purpose and advantages of the present application, wherein:

[0035] Figure 1 A topological schematic diagram of an isolation circuit for a hydrogen production system according to an embodiment of the present application;

[0036] Figure 2 A topological schematic diagram of an isolation circuit for a hydrogen production system according to another embodiment of the present application;

[0037] Figure 3 A topological schematic diagram of an isolation circuit for a hydrogen production system according to another embodiment of the present application;

[0038] Figure 4 This is a structural block diagram of a renewable energy hydrogen production system according to an embodiment of the present application;

[0039] Figure 5 This is a structural block diagram of a renewable energy hydrogen production system according to another embodiment of the present application;

[0040] Figure 6 This is a structural block diagram of a renewable energy hydrogen production system as another specific example of the present application;

[0041] Figure 7 A topological diagram of a DC / DC converter according to an embodiment of the present application;

[0042] Figure 8A topological diagram of an AC / DC converter according to an embodiment of the present application;

[0043] Fig. 9 This is a flow chart of a control method for a renewable energy hydrogen production system according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than 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 the present application.

[0045] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0046] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] This embodiment provides an isolation circuit for a hydrogen production system, such as Figure 1-Figure 3 As shown, including:

[0048] At least one DC conversion module and at least one DC-AC converter; as shown in the dotted box in the figure, the DC conversion module is formed by a combination of multiple internal DC-AC converters and one internal AC-DC converter, and includes a single output port and a multiple output port. The single output port of the DC conversion module is coupled to the DC side of the external DC-AC converter; the multiple output ports of the DC conversion module are coupled to multiple external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow unit includes at least a hydrogen production unit; wherein the AC end of the external DC-AC converter is coupled to the external AC grid or DC grid in series.

[0049] Figure 1-Figure 3 In the embodiment, when the DC conversion module is externally connected to a renewable energy power generation unit or a hydrogen production unit, the DC conversion module can adopt a conversion module with a DC-DC function having an isolation function, that is, a combination structure including a DC-AC converter and an AC-DC converter is used. Figure 3 As shown, if the DC conversion module is externally connected to an energy storage unit, it can be directly connected to a DC-DC converter with a DC conversion function without adding an isolation function.

[0050] The isolation circuit provided in the above embodiment includes at least one DC conversion module and at least one DC-AC converter, the DC conversion module includes a single output port and a multi-output port; the single output port of the DC conversion module is coupled and connected to the DC side of the DC-AC converter; the multi-output port of the DC conversion module is coupled and connected to multiple external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow unit includes at least a hydrogen production unit; the AC end of the DC-AC converter is coupled and connected in series with the external AC power grid or DC power grid. Therefore, this scheme has reserved a coupling port for the external AC power grid or DC power grid, which can be applied to both AC coupling and DC coupling, and meets the application requirements of both coupling situations. In specific use, the port of the unidirectional power flow unit and / or the bidirectional power flow unit is directly connected to the output port of the isolation circuit to complete the coupling connection of the entire system. The above scheme of the present application can adopt a simple method to effectively integrate various types of external units, integrate various components in the system into one, reduce costs, and facilitate fault location and repair.

[0051] In the above solution, the unidirectional power flow unit includes a hybrid hydrogen production unit and / or a new energy power generation unit; the hybrid hydrogen production unit includes two or more hydrogen production modules; and the bidirectional power flow unit includes an energy storage unit. In specific implementation, the number and type of the unidirectional power flow units and the bidirectional power flow units required can be configured according to the actual application scenario, and a plurality of the unidirectional power flow units are coupled to the multiple output ports in parallel.

[0052] The present application also provides a renewable energy hydrogen production system, Figure 4 and Figure 5 As shown, it includes at least one isolation circuit for a hydrogen production system according to any one of the above embodiments, and at least one renewable energy power generation unit, each of the renewable energy power generation units is coupled and connected to an output port of the isolation circuit; at least one energy storage unit, the energy storage unit is coupled and connected to an output port of the isolation circuit; at least one hydrogen production unit, the hydrogen production unit is coupled and connected to an output port of the isolation circuit.

[0053] Through the above scheme, the isolation circuit can establish a hydrogen production system architecture that fully adapts to the volatility of renewable energy as needed by connecting different functional units. The renewable energy power generation unit is connected to the isolation circuit, and the isolation circuit is also connected to the hydrogen production unit and the energy storage unit. With this system, when the energy generated by the renewable energy power generation unit fluctuates, according to the time scale of the fluctuation, for short-term fluctuations, the power-type hydrogen production unit can be directly used for adjustment and compensation, and for long-term fluctuations, the energy-type hydrogen production unit can be used for adjustment and compensation. And through the power-type and energy-type energy storage units, the self-regulation capabilities of the power-type and energy-type hydrogen production units are compensated and optimized, so as to achieve the dual requirements of steady-state energy balance and dynamic power tracking of the system in the hydrogen production application of the whole process of new energy power generation.

[0054] like Figure 4 and Figure 5 As shown in the figure, the system architecture and topology of the renewable energy hydrogen production system mainly include four scalable levels:

[0055] (1) When the bottom submodule ISub Module is a multi-port high-frequency isolated DC-DC module, the multi-port side can be coupled to connect and expand multiple renewable energy power generation units, energy storage units and hydrogen production units. The coupling connection method is to realize the parallel connection of i groups of multiple energy units through the above-mentioned isolation circuit with isolation function, where i can be expanded according to application requirements. Assuming that the number of renewable energy power generation units is u, the number of energy storage units is v, and the number of electrolyzers of the hydrogen production unit is w, then i satisfies the following formula: i=u+v+w, where u, v and w can all be expanded according to requirements.

[0056] (2) The bottom submodule ISub Module is a multi-port unidirectional flow energy device of the same type, which can be directly connected in parallel in j groups to meet the scale requirements. Among them, j can be expanded according to application requirements.

[0057] (3) When the middle-level submodule (i.e., the external DC-AC converter) is a non-isolated DC-AC module, the single-port DC end of the bottom-level submodule (ISub ​​Module) is connected to the DC end of the middle-level submodule (ISub ​​Module): the DC end of the DC-AC converter, and the AC end of the middle-level submodule (ISub ​​Module) can be connected in series with the AC bus coupling end (or connected to the DC bus coupling end based on the MMC connection method), where n can be expanded according to application requirements.

[0058] (4) The middle-level sub-modules are connected in series to form an upper-level cascade system, which has two implementations: an AC connection structure or a DC connection structure. m groups of upper-level cascade systems can be connected in parallel through an AC bus or a DC bus to form an overall cascade architecture, where m can be expanded according to application requirements.

[0059] Since four scalable levels are used to form a scalable architecture for renewable energy hydrogen production, the power allocation and optimization of different types of energy devices can be optimized, combined and calculated according to the following maximum power allocation boundaries.

[0060] The maximum power generation capacity of renewable energy generation unit satisfies the formula

[0061] The maximum power range of energy storage unit charging and discharging satisfies the formula

[0062] The maximum power demand of hydrogen production unit meets the public notice

[0063] In the above formula, 3 refers to three phases, n is the series number of the middle-level submodules, m is the parallel number of the upper-level cascade system, px represents the power of the x-th new energy power generation unit, py represents the power of the y-th energy storage unit, and pz represents the power of the z-th hydrogen production unit.

[0064] Based on the above architecture, according to the type of unidirectional power flow units and / or bidirectional power flow units external to the system, this solution proposes a two-level working mode optimization method, namely, a single combination mode and a mixed combination mode. The difference is that the single combination mode mainly considers a single power flow path in a single direction, and the mixed combination mode mainly considers a combination of two power flow paths in more than two directions.

[0065] (1) The specific definition of a single combination model is as follows:

[0066] 1.1 If the system operating mode is the new energy basic grid-connected mode: control the power path direction of the isolation circuit to realize the unidirectional power flow direction from a single type of renewable energy power generation unit to the AC or DC bus unit.

[0067] 1.2 If the system operating mode is the energy storage-based grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve a bidirectional power flow direction from a single type of energy storage unit to an AC or DC bus unit.

[0068] 1.3 If the system operating mode is the grid-connected basic hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to the single type of hydrogen production unit.

[0069] (2) The specific definition of the hybrid combination model is as follows:

[0070] 2.1 If the system working mode is the new energy hybrid grid-connected mode Mrex: control the power Pmrex path direction of the isolation circuit to realize the unidirectional power flow direction from multiple types of renewable energy power generation units to the AC or DC bus unit.

[0071] 2.2 If the system operating mode is the energy storage hybrid grid-connected charging / discharging mode (Mesx1 / Mesx2): control the power (Pmesx1 / Pmesx2) path direction of the isolation circuit to realize the bidirectional power flow direction from multiple types of energy storage units to the AC or DC bus units.

[0072] 2.3 If the system operating mode is the grid-connected hybrid hydrogen production mode Melx: control the power Pmelx path direction of the isolation circuit to realize the direction of power from the AC or DC bus to multiple types of hydrogen production units.

[0073] The above six combination modes constitute the basic application mode of the architecture, and the above six combination modes can be further repeatedly superimposed to achieve comprehensive coverage of power flow control in all scenarios of the system. Typical implementation combinations are shown in Table 1.

[0074] Table 1 System working mode combination example table

[0075]

[0076]

[0077] As shown in Table 1, according to different operating modes, the green hydrogen index can be defined according to the utilization rate of renewable energy in the hydrogen production process to determine the preferred principle of the hydrogen production process. Among them, the second mode combination and the fourth mode combination have the highest green hydrogen index and belong to the highest priority hydrogen production mode. The sixth mode combination and the seventh mode have relatively high and very high green hydrogen indexes respectively. The determining factor mainly depends on whether the source of energy storage electricity is all renewable energy. The green hydrogen index of the third mode combination is medium, and the determining factor comes from whether the source of power supply from the power grid is renewable energy. The green hydrogen index is low in the two scenarios of the first mode combination, which mainly provides auxiliary support such as stability for the hydrogen production process.

[0078] This solution adopts an extended design of multi-port high-frequency isolation, which can simultaneously connect to other types of energy units other than the hydrogen production unit electrolyzer, such as energy storage units and renewable energy power generation units. Therefore, it can provide more directly coupled renewable energy power generation for electrolyzer hydrogen production, and perform smoothing and stability control through energy storage. In addition, multi-port isolation also makes it possible to cooperate with different hydrogen production units. For example, by simultaneously connecting to an alkaline electrolyzer and a PEM electrolyzer, the complementary characteristics of the two hydrogen production devices can be fully utilized to establish a more cost-effective hybrid hydrogen production mode and control. In addition, the underlying submodule ISub Module can be extended in parallel between energy devices of the same type with unidirectional flow, so large-capacity alkaline electrolyzers of different levels can be integrated. For example, for an alkaline electrolyzer with tens of thousands of amperes, the operating current of the underlying submodule ISub Module can be made more reasonable by reasonably selecting the j value, so as to optimize the design of the underlying submodule ISub Module to improve the cost-effectiveness of the system.

[0079] like Figure 6-Figure 8 A specific embodiment of a hybrid hydrogen production system for an AC power grid. Figure 6 The isolation circuit shown is used as a bottom-level submodule ISub Module. The bottom-level submodule ISub Module is composed of a single-ended output isolated DC-DC converter, and its circuit topology is not limited to series resonance, phase-shifted full-bridge, LLC, etc. Figure 6 In the structure shown, the number of new energy power generation units is zero, the number of energy storage units is zero, and the number of hydrogen production units is 2. And because the hydrogen production unit is a unidirectional flow type energy device, therefore, Figure 6 The architecture shown can realize j groups of direct parallel connection to meet the scale demand. In the specific implementation, in this embodiment, 150 modules (3 phases) of alkaline hydrogen production modules and 60 modules of PEM hydrogen production modules are connected in parallel respectively. Figure 7 Given Figure 6 One implementation of each DC-DC converter in, Figure 8 Given Figure 6 The implementation method of the middle DC-AC (DC side is connected to the DC-DC converter, and the AC side is connected to the grid through an inductor) converter. The DC-AC converter is connected to the bottom submodule ISubModule as a middle-level DC-AC module. The middle-level DC-AC module is an H-bridge circuit. The hydrogen production unit includes an alkaline hydrogen production unit ALK and a PEM hydrogen production unit. If the grid voltage is assumed to be 35kV, the gain of the isolated DC / DC converter is selected to be 1, and the minimum operating voltage Udc_min of the hydrogen production unit is assumed to be 500V, it can be calculated that the minimum number of middle-level submodules SubModule after each phase cascade is N=65.

[0080]

[0081] Where Us is the rated voltage of the power grid; k v k is the correction coefficient under the condition of maximum fluctuation of grid voltage, which is 1.07; b k is the correction factor for the most severe voltage imbalance, which is 1.02; L It is the correction coefficient of the maximum voltage drop of the grid-connected reactance and is taken as 1.1.

[0082] In order to improve the reliability of the system, considering the 5% redundancy design, the total number of Sub Module modules per phase of the system is set to 70. Since the power of the alkaline electrolyzer is much higher than that of the PEM electrolyzer and is greater than the maximum power of a single module, it can be connected in parallel at the output of the ISubModule. The specific number of parallel connections should be determined according to the power ratio of the alkaline electrolysis system and the PEM electrolysis system. Assuming that the power ratio of the alkaline hydrogen production system to the PEM hydrogen production system is 5:2, there should be 50 ISubModule outputs in each phase connected in parallel to the alkaline hydrogen production system, and 20 ISubModule outputs connected in parallel to the PEM hydrogen production system. Since the phases of A, B, and C differ by 120° respectively, the current ripple of the input electrolysis system can be further reduced after parallel connection.

[0083] Considering that the response speed of the PEM hydrogen production unit is much faster than that of the alkaline hydrogen production system, the power flowing into the alkaline system and the PEM hydrogen production system can be flexibly modulated by controlling the voltage on the AC side of the Sub Module, so as to quickly respond to and accurately track the dispatching instructions of the power grid, that is, by controlling the voltage gain ratio of the DC-DC in the bottom submodule, the current distribution ratio and the current change rate of the DC-DC can be controlled to meet the dynamic needs of different hydrogen production units. The system architecture of the present application realizes high voltage by connecting different units in series, and does not require a step-down transformer, so it can help to improve the response speed. In addition, the cascade topology in this scheme can be regarded as multiple small power supplies (AC-DC+DC-DC) connected in parallel and then connected to the hydrogen production unit, because for the same converter topology, the smaller the power supply power, the smaller the inductance value required, so relative to a single large power supply, the dynamic characteristics of this scheme are good. In the present application scheme, multiple modules in the three phases A, B, and C are connected in parallel to naturally produce staggered parallel operation characteristics, which can further offset the ripple current, thereby reducing the required filter inductance value and improving the dynamic characteristics.

[0084] The present application also provides a control method for the renewable energy hydrogen production system described in any one of the above items, such as Fig. 9 As shown, including:

[0085] S100: Determine a system operating mode according to the type of a unidirectional power flow unit and / or a bidirectional power flow unit external to the system.

[0086] S211: If the system operating mode is the new energy basic grid-connected mode: control the power path direction of the isolation circuit to realize the unidirectional power flow direction from a single type of renewable energy power generation unit to the AC or DC bus.

[0087] S212: If the system operating mode is the energy storage-based grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve a bidirectional power flow direction from a single-type energy storage unit to an AC or DC bus.

[0088] S213: If the system operating mode is the grid-connected basic hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to the single type of hydrogen production unit.

[0089] S221: If the system operating mode is a new energy hybrid grid-connected mode: control the power path direction of the isolation circuit to achieve a unidirectional power flow direction from multiple types of renewable energy power generation units to the AC or DC bus.

[0090] S222: If the system operating mode is the energy storage hybrid grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve a bidirectional power flow direction from multiple types of energy storage units to the AC or DC bus units.

[0091] S223: If the system operating mode is a grid-connected hybrid hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to multiple types of hydrogen production units.

[0092] Through the above-mentioned scheme of the present application, the scale of the renewable energy hydrogen production process can be guaranteed, and the AC coupling or DC coupling requirements in both grid-connected and off-grid modes can be met. The high-frequency isolation multi-port characteristics of the isolation circuit are utilized to optimize the energy flow paths and processes of different hydrogen production modes and renewable energy and energy storage. This cascaded large-scale renewable energy hydrogen production system control method based on high-frequency isolation multi-port modules can greatly improve the adaptability of the hydrogen production process to the volatility of renewable energy and the level of equipment utilization, further optimize the standardized combination and modular production of large-scale renewable energy hydrogen production structures, reduce system architecture and control customization, complexity and operation and maintenance costs, thereby improving system reliability, safety and economy.

[0093] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. An isolation circuit for a hydrogen production system, characterized in that: include: At least one DC conversion module, the DC conversion module comprising a single output port and a multi-output port; at least one DC-AC converter; The single output port of the DC conversion module is coupled and connected to the DC side of the DC-AC converter; The multiple output ports of the DC conversion module are coupled to multiple external unidirectional power flow units and / or bidirectional power flow units, and the unidirectional power flow unit at least includes a hydrogen production unit; The AC side of the DC-AC converter is coupled to an external AC grid or a DC grid in series.

2. The isolation circuit for a hydrogen production system according to claim 1, characterized in that: The unidirectional power flow unit includes a hybrid hydrogen production unit and / or a new energy power generation unit; the hybrid hydrogen production unit includes two or more hydrogen production modules; The bidirectional power flow unit includes an energy storage unit.

3. The isolation circuit for a hydrogen production system according to claim 2, characterized in that: A plurality of the unidirectional power flow units are coupled to the multiple output ports in parallel.

4. The isolation circuit for a hydrogen production system according to claim 2, characterized in that: When the DC conversion module is connected to the hybrid hydrogen production unit or the new energy power generation unit, the DC conversion module is configured with an isolation unit.

5. A renewable energy hydrogen production system, characterized in that: The invention comprises at least one isolation circuit for a hydrogen production system according to any one of claims 1 to 4, and: At least one renewable energy power generation unit, each of the renewable energy power generation units is coupled to an output port of the isolation circuit; At least one energy storage unit, the energy storage unit is coupled to an output port of the isolation circuit; At least one hydrogen production unit is coupled to an output port of the isolation circuit.

6. The renewable energy hydrogen production system according to claim 5, characterized in that: When the renewable energy generation unit includes a plurality of units, the plurality of renewable energy generation units are coupled to the plurality of output ports of the isolation circuit in parallel.

7. The renewable energy hydrogen production system according to claim 5, characterized in that: When the renewable energy generation unit comprises a plurality of units, the plurality of renewable energy generation units are divided into a plurality of parallel coupling groups; The renewable energy generation units in each of the parallel coupling groups are coupled to the parallel coupling ports in a parallel manner; and the parallel coupling ports in a plurality of the parallel coupling groups are coupled to the plurality of output ports of the isolation circuit in a parallel manner.

8. The renewable energy hydrogen production system according to claim 5, characterized in that: When the hydrogen production unit includes a plurality of units, the types of the hydrogen production units include at least two.

9. The renewable energy hydrogen production system according to claim 8, characterized in that: The hydrogen production unit comprises an alkaline hydrogen production module, a solid oxide hydrogen production module and a PEM hydrogen production module.

10. A control method for a renewable energy hydrogen production system according to any one of claims 5 to 9, characterized in that: include: Determine the system operation mode according to the type of the unidirectional power flow unit and / or the bidirectional power flow unit external to the system; If the system operation mode is a new energy basic grid-connected mode: control the power path direction of the isolation circuit to achieve a unidirectional power flow direction of power from a single type of renewable energy generation unit to an AC or DC bus unit; If the system operation mode is the energy storage-based grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve the direction of bidirectional power flow from a single type of energy storage unit to an AC or DC bus unit; If the system operating mode is a grid-connected basic hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to the single type of hydrogen production unit.

11. The control method of the renewable energy hydrogen production system according to claim 10, characterized in that: Also includes: If the system operation mode is a new energy hybrid grid-connected mode: control the power path direction of the isolation circuit to achieve the direction of unidirectional power flow from multiple types of renewable energy power generation units to the AC or DC bus unit; If the system operation mode is a hybrid energy storage grid-connected charging / discharging mode: control the power path direction of the isolation circuit to achieve a bidirectional power flow direction from multiple types of energy storage units to the AC or DC bus unit; If the system operation mode is a grid-connected hybrid hydrogen production mode: control the power path direction of the isolation circuit to realize the direction of power from the AC or DC bus to multiple types of hydrogen production units.

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