Off-grid green electricity hydrogen production micro-grid regulation and control system

Abstract

The utility model discloses an off-grid green electricity hydrogen production micro-grid regulation and control system which comprises a photovoltaic power generation unit, energy storage units, a standby energy supply unit, a power supply and distribution tandem execution unit, a hydrogen production system and an upper energy management unit. And the power of the photovoltaic module is transmitted to the power supply and distribution tandem execution unit through the inverter for power supply and distribution. In order to ensure that the two groups of energy storage devices supply energy uninterruptedly and stably in the switching process, an additional standby energy supply unit is added. The hydrogen production system is used as a terminal device of photovoltaic power generation local consumption, can adjust the imbalance of hydrogen production instantaneous power through the energy storage unit, and reduces the influence of power generation volatility; the upper energy management unit mainly carries out overall coordination on all the subunits, through reasonable distribution and scheduling of energy, the influence of randomness and volatility of renewable energy on a hydrogen production system is reduced, hydrogen production continuity and hydrogen production efficiency are maintained, and maximum absorption is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy hydrogen production, in particular to an off-grid green electricity hydrogen production microgrid control system. Background Art

[0002] Under the background of "dual carbon" goal and energy security, my country's hydrogen energy industry has ushered in explosive growth. Various regions have actively promoted the strategic layout of the hydrogen energy industry and seized the opportunity of hydrogen energy development. Hydrogen energy is a green, low-carbon and widely used secondary energy. It can help large-scale consumption of renewable energy, realize grid peak regulation and cross-seasonal and cross-regional energy storage, and accelerate the low-carbonization of industries, construction, transportation and other fields. In particular, the production of green hydrogen with renewable energy as the main body is regarded as an ideal model for achieving carbon neutrality. It is the only hydrogen production technology route that can achieve zero carbon emissions throughout the entire cycle. In terms of promoting the consumption of renewable energy, the green electricity production system with alkaline electrolyzer as the core is an important means to achieve 100% renewable energy consumption and 100% zero-carbon power supply. It has the characteristics of a wide power operation range and good adaptability to renewable energy fluctuations. Coupling hydrogen energy with renewable energy generation can effectively reduce the impact of renewable energy on the power grid and promote the consumption of renewable energy. At the same time, hydrogen-electricity coupled energy storage uses hydrogen and derivative gases as storage media, which can achieve large-scale long-term energy storage with a scale ranging from megawatts to hundreds of megawatts and a storage time from hours to seasons.

[0003] According to different sources of electricity, renewable energy hydrogen production technology is divided into two types: grid-connected and off-grid. Grid-connected hydrogen production is a method of connecting wind and solar power generation to the grid and then taking electricity from the grid. At present, commercial photovoltaic power generation hydrogen production basically adopts the grid-connected method, which requires DC / AC / DC three-stage conversion. The hydrogen production system is complex, costly, has large power loss, and is highly dependent on the grid. The off-grid mode uses DC / DC two-stage conversion, which can reduce dependence on the grid, has flexible scale and capacity settings, and low electricity price costs. There are three types of topological structures for renewable energy green hydrogen production systems: AC bus, DC bus, and mixed bus. The main difference lies in the different forms of energy transmission and distribution. The AC bus microgrid structure is mainly based on three-phase AC power. It is the most mature technology, the most widely used, and the easiest to connect to the grid in the hydrogen production system. However, there are factors such as complex system structure, complex control strategy and algorithm, difficulty in controlling the frequency and voltage stability of energy storage unit access, and the unstable power generation of micro power sources that have a great impact on terminal loads. The DC busbar microgrid structure is mainly based on DC. As an emerging technology, it has begun to be promoted and applied at home and abroad. It uses semiconductor and phase control technology. The equipment cost is relatively high. It needs to design a specific distribution system for grid-connected operation. The energy loss is small and the system structure is relatively simple. It has great application prospects in the field of off-grid microgrids. The mixed-current busbar microgrid is a relatively complex microgrid structure configured according to the ratio of new energy power generation methods (such as photovoltaic and wind power) and downstream AC and DC power equipment. It takes into account the advantages and disadvantages of AC and DC busbar structures and can be configured according to actual working conditions. According to the characteristics of the above-mentioned renewable energy hydrogen production microgrid structures, the off-grid renewable energy green hydrogen production system involved in this patent adopts an AC bus-based topology to build a hardware environment. Two sets of energy storage devices are configured to provide the system with a bus voltage source, which is switched between each other for standby. The microgrid topology is simple, and the energy storage maintains good bus voltage stability and low volatility. The communication between each sub-unit adopts a bus standard interface with good compatibility. At the same time, the upper-level energy management system is used to reasonably allocate and schedule energy for each sub-unit, reducing the impact of the randomness and volatility of photovoltaic power generation on the hydrogen production system, and maintaining the continuity and efficiency of hydrogen production. Utility Model Content

[0004] The purpose of the utility model is to provide an off-grid green electricity hydrogen production microgrid control system to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] An off-grid green electricity hydrogen production microgrid control system, comprising a power supply and distribution tandem execution unit, the power supply and distribution tandem execution unit serving as a system power distribution node and connected to a photovoltaic power generation unit, a first energy storage unit, a second energy storage unit, a backup power supply unit, and a hydrogen production system through an AC cable;

[0007] The photovoltaic power generation unit includes a first photovoltaic component, the output end of the first photovoltaic component is connected to the photovoltaic grid-connected inverter, the output end of the photovoltaic grid-connected inverter is connected to the power supply and distribution connection execution unit; the first energy storage unit includes a second photovoltaic component, the output end of the second photovoltaic component is connected to the first photovoltaic controller, the output end of the first photovoltaic controller is connected to the first energy storage battery group, the output end of the first energy storage battery group is connected to the first inverter, and the output end of the first inverter is connected to the power supply and distribution connection execution unit; the second energy storage unit includes a third photovoltaic component, the output end of the third photovoltaic component is connected to the second photovoltaic controller, the output end of the second photovoltaic controller is connected to the second energy storage battery group, the output end of the second energy storage battery group is connected to the second inverter, and the output end of the second inverter is connected to the power supply and distribution connection execution unit; the backup power supply unit includes a UPS backup power supply, the discharge interface and the charging interface of the UPS backup power supply are sequentially connected to the power supply and distribution connection execution unit; the input end of the hydrogen production system is connected to the power supply and distribution connection execution unit;

[0008] The photovoltaic grid-connected inverter, the first photovoltaic controller, the first energy storage battery group, the first inverter, the second photovoltaic controller, the second energy storage battery group, and the second inverter are connected to the input end of the system server through a system bus, and the output end of the system server is respectively connected to the power supply and distribution connection execution unit and the hydrogen production system.

[0009] Preferably, the first photovoltaic components are connected in series via DC cables to form a photovoltaic string, and multiple photovoltaic strings are connected in parallel to a photovoltaic grid-connected inverter.

[0010] The working process of the utility model is:

[0011] The utility model is composed of a photovoltaic power generation unit, an energy storage unit, a backup energy supply unit, a power supply and distribution connection execution unit, a hydrogen production system and an upper energy management unit. The photovoltaic components of the photovoltaic power generation unit supply power to the system through a photovoltaic inverter; the system is equipped with two groups of energy storage devices as bus voltage sources, and a single group of energy storage devices supplies the power of the photovoltaic components to the energy storage battery through a photovoltaic controller, and transmits it to the power supply and distribution connection execution unit through an inverter for power supply distribution and stable bus voltage. The backup energy supply unit mainly provides uninterrupted energy supply for the two groups of energy storage to switch between each other. The two groups of energy storage devices are backup for each other to ensure that the microgrid bus voltage is within the rated range and ensure uninterrupted and stable operation of the system; the hydrogen production system is a lower-end energy consumption device; the upper energy management unit coordinates the sub-units, and performs data analysis and energy scheduling through the system bus. Its goal is to reduce the impact of the randomness and volatility of renewable energy on the water electrolysis hydrogen production system, achieve maximum renewable energy consumption, maintain the continuity of hydrogen production and improve hydrogen production efficiency.

[0012] When using this off-grid green electricity hydrogen production microgrid system: start one of the energy storage devices, and use the first photovoltaic controller and the second photovoltaic controller to charge the first energy storage battery group and the second energy storage battery group; the purpose is to charge the first energy storage battery group and the second energy storage battery group so that they have enough electricity to meet the system operation, and secondly, judge the current power generation of the photovoltaic power generation unit according to the output power of the first photovoltaic controller and the second photovoltaic controller, and then determine the operating power and hydrogen production of the terminal hydrogen production device.

[0013] When the microgrid system is running, the system server obtains real-time photovoltaic meteorological data from the network end. The energy control system sends control instructions to the terminal hydrogen production system in advance according to the change of solar radiation intensity by the energy control strategy, so that it can adjust the corresponding operating state under different lighting conditions; the two energy storage devices are mutually backup, one group is composed of the first energy storage battery group and the second energy storage battery group, which discharges through the inverter to provide a stable bus voltage to the power grid and supply energy to the terminal hydrogen production system at the same time, and the other group is composed of the second photovoltaic module and the third photovoltaic module, which charge the first energy storage battery group and the second energy storage battery group through the first photovoltaic controller and the second photovoltaic controller; the UPS backup power supply can provide power supply conditions for the safe shutdown of the hydrogen production device when a system failure occurs, and at the same time, it serves as an intermediate transition when the two energy storage devices are switched to ensure the stability of the system bus voltage. The power supply and distribution tandem execution unit can be used to switch in and out various parts of the system, collect data, and adjust system operation parameters.

[0014] The control system and method involved in the utility model are suitable for a microgrid environment in an off-grid renewable energy green electricity hydrogen production scenario.

[0015] The beneficial effects of the utility model are:

[0016] (1) The utility model realizes the effect of dynamically adjusting the randomness and volatility of renewable energy by using the energy storage unit as the system bus voltage source.

[0017] (2) The utility model integrates photovoltaic power generation units, energy storage units, backup energy supply units, power supply and distribution connection execution units, hydrogen production systems and upper-level energy management units, and opens up the conversion technology of microgrid electricity-hydrogen coupling in terms of off-grid hydrogen production unit equipment combination integration and energy management process, which can meet the needs of industrial scale-up of hydrogen-electricity coupling systems.

[0018] (3) The utility model provides a bus voltage source for the system by configuring two sets of energy storage devices, which are switched between each other for standby. The microgrid topology is simple, the energy storage maintains the bus voltage with good stability and small volatility, and the communication of each sub-unit adopts a bus standard interface with good compatibility.

[0019] (4) The utility model also utilizes the upper-level energy management system to reasonably allocate and dispatch the energy of each sub-unit, thereby reducing the impact of the randomness and volatility of photovoltaic power generation on the hydrogen production system and maintaining the continuity and efficiency of hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the utility model;

[0021] In the figure: 1-first photovoltaic module, 2-photovoltaic grid-connected inverter, 3-second photovoltaic module, 4-first photovoltaic controller, 5-first energy storage battery group, 6-first inverter, 7-third photovoltaic module, 8-second photovoltaic controller, 9-second energy storage battery group, 10-second inverter, 11-power supply and distribution connection execution unit, 12-UPS backup power supply, 13-hydrogen production system, 14-system server, 15-system bus. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] like Figure 1 An off-grid green electricity hydrogen production microgrid control system is shown, which uses an AC bus as an energy transmission and distribution method, and includes a power supply and distribution tandem execution unit 11, which serves as a system power distribution node and is connected to a photovoltaic power generation unit, a first energy storage unit, a second energy storage unit, a backup power supply unit, and a hydrogen production system 13 through AC cables;

[0024] The photovoltaic power generation unit includes a first photovoltaic component 1, the output end of the first photovoltaic component 1 is connected to a photovoltaic grid-connected inverter 2, the first photovoltaic components 1 are connected in series through DC cables to form a photovoltaic string, multiple photovoltaic strings are connected in parallel to the photovoltaic grid-connected inverter 2, and the output end of the photovoltaic grid-connected inverter 2 is connected to a power supply and distribution connection execution unit 11; the first energy storage unit includes a second photovoltaic component 3, the output end of the second photovoltaic component 3 is connected to a first photovoltaic controller 4, the output end of the first photovoltaic controller 4 is connected to a first energy storage battery group 5, the output end of the first energy storage battery group 5 is connected to a first inverter 6, and the output end of the first inverter 6 is connected to a power supply and distribution connection execution unit 11. The power connection execution unit 11; the second energy storage unit includes a third photovoltaic module 7, the output end of the third photovoltaic module 7 is connected to the second photovoltaic controller 8, the output end of the second photovoltaic controller 8 is connected to the second energy storage battery group 9, the output end of the second energy storage battery group 9 is connected to the second inverter 10, and the output end of the second inverter 10 is connected to the power supply and distribution connection execution unit 11; the backup power supply unit includes a UPS backup power supply 12, the discharge interface and the charging interface of the UPS backup power supply 12 are connected to the power supply and distribution connection execution unit 11 in sequence; the input end of the hydrogen production system 13 is connected to the power supply and distribution connection execution unit 11;

[0025] The photovoltaic grid-connected inverter 2, the first photovoltaic controller 4, the first energy storage battery group 5, the first inverter 6, the second photovoltaic controller 8, the second energy storage battery group 9, and the second inverter 10 are connected to the input end of the system server 14 through the system bus 15, and the output end of the system server 14 is respectively connected to the power supply and distribution connection execution unit 11 and the hydrogen production system 13.

[0026] The working process of the utility model is:

[0027] The utility model is composed of a photovoltaic power generation unit, an energy storage unit, a backup energy supply unit, a power supply and distribution connection execution unit, a hydrogen production system and an upper energy management unit. The photovoltaic components of the photovoltaic power generation unit supply power to the system through a photovoltaic inverter; the system is equipped with two groups of energy storage devices as bus voltage sources, and a single group of energy storage devices supplies the power of the photovoltaic components to the energy storage battery through a photovoltaic controller, and transmits it to the power supply and distribution connection execution unit through an inverter for power supply distribution and stable bus voltage. The backup energy supply unit mainly provides uninterrupted energy supply for the two groups of energy storage to switch between each other. The two groups of energy storage devices are backup for each other to ensure that the microgrid bus voltage is within the rated range and ensure uninterrupted and stable operation of the system; the hydrogen production system is a lower-end energy consumption device; the upper energy management unit coordinates the sub-units, and performs data analysis and energy scheduling through the system bus. Its goal is to reduce the impact of the randomness and volatility of renewable energy on the water electrolysis hydrogen production system, achieve maximum renewable energy consumption, maintain the continuity of hydrogen production and improve hydrogen production efficiency.

[0028] When using this off-grid green electricity hydrogen production microgrid system: start one of the energy storage devices, and use the first photovoltaic controller 4 and the second photovoltaic controller 8 to charge the first energy storage battery group 5 and the second energy storage battery group 9; its purpose is to charge the first energy storage battery group 5 and the second energy storage battery group 9 so that they have enough electricity to meet the system operation, and secondly, judge the current power generation of the photovoltaic power generation unit according to the output power of the first photovoltaic controller 4 and the second photovoltaic controller 8, and then determine the operating power and hydrogen production of the terminal hydrogen production device.

[0029] When the microgrid system is running, the system server 14 obtains real-time photovoltaic meteorological data from the network end, and the energy control system pre-issues control instructions to the terminal hydrogen production system 13 according to the change of solar radiation intensity by the energy control strategy, so that it can adjust the corresponding operating state under different lighting conditions; the two groups of energy storage devices are mutually backup, one group is composed of the first energy storage battery group 5 and the second energy storage battery group 9, which discharges through the inverter to provide a stable bus voltage to the power grid and supply energy to the terminal hydrogen production system, and the other group is composed of the second photovoltaic module 3 and the third photovoltaic module 7, which charges the first energy storage battery group 5 and the second energy storage battery group 9 through the first photovoltaic controller 4 and the second photovoltaic controller 8; the UPS backup power supply 12 can provide power supply conditions for the safe shutdown of the hydrogen production device when a system failure occurs, and at the same time, it serves as an intermediate transition when the two groups of energy storage devices are switched to ensure the stability of the system bus voltage. The power supply and distribution tandem execution unit 11 can be used to switch in and out various parts of the system, collect data, and adjust system operation parameters.

[0030] The above are only preferred examples of the present invention. It should be pointed out that for ordinary technicians in this field, under the technical inspiration provided by the present invention, as common knowledge in the field of new energy, other equivalent variations and improvements can be made, which should also be regarded as the protection scope of the present invention.

Claims

1. An off-grid green electricity hydrogen production microgrid control system, which uses AC bus as an energy transmission and distribution method, and is characterized by: It comprises a power supply and distribution tandem execution unit (11), the power supply and distribution tandem execution unit (11) serving as a system power distribution node and connected to a photovoltaic power generation unit, a first energy storage unit, a second energy storage unit, a backup power supply unit, and a hydrogen production system (13) respectively through an AC cable; The photovoltaic power generation unit comprises a first photovoltaic component (1), the output end of the first photovoltaic component (1) is connected to a photovoltaic grid-connected inverter (2), the output end of the photovoltaic grid-connected inverter (2) is connected to a power supply and distribution junction execution unit (11); the first energy storage unit comprises a second photovoltaic component (3), the output end of the second photovoltaic component (3) is connected to a first photovoltaic controller (4), the output end of the first photovoltaic controller (4) is connected to a first energy storage battery group (5), the output end of the first energy storage battery group (5) is connected to a first inverter (6), the output end of the first inverter (6) is connected to the power supply and distribution junction execution unit (11); the second energy storage unit comprises a third photovoltaic assembly (7), the output end of the third photovoltaic assembly (7) is connected to a second photovoltaic controller (8), the output end of the second photovoltaic controller (8) is connected to a second energy storage battery group (9), the output end of the second energy storage battery group (9) is connected to a second inverter (10), and the output end of the second inverter (10) is connected to a power supply and distribution junction execution unit (11); the backup power supply unit comprises a UPS backup power supply (12), the discharge interface and the charging interface of the UPS backup power supply (12) are connected to the power supply and distribution junction execution unit (11) in sequence; the input end of the hydrogen production system (13) is connected to the power supply and distribution junction execution unit (11); The photovoltaic grid-connected inverter (2), the first photovoltaic controller (4), the first energy storage battery group (5), the first inverter (6), the second photovoltaic controller (8), the second energy storage battery group (9), and the second inverter (10) are connected to the input end of the system server (14) via a system bus (15), and the output end of the system server (14) is respectively connected to the power supply and distribution tandem execution unit (11) and the hydrogen production system (13).

2. The off-grid green electricity hydrogen production microgrid control system according to claim 1 is characterized by: The first photovoltaic components (1) are connected in series via direct current cables to form a photovoltaic string, and a plurality of photovoltaic strings are connected in parallel to a photovoltaic grid-connected inverter (2).

Images