On-off grid Switching Hybrid-type Heterogeneous Electrolysis System and Its Control Method

Abstract

The present invention relates to a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof, which can switch power to supply an AEM and PEM type water electrolysis system with a relatively low minimum load or an AWE type water electrolysis system with a relatively high minimum load but a high hydrogen production capacity, depending on the predicted value of renewable energy generation. A heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention for solving the above problems comprises: an eco-friendly power generation system; an external power grid; an energy storage device; a heterogeneous water electrolysis system; a power prediction and supply unit; and a power distributor, wherein the power prediction and supply unit comprises a renewable energy generation amount prediction unit; an external power information collection unit; an energy storage device status detection unit; a power supply switching unit; and a control unit, wherein the power distributor controls the supply of power to the Alkaline Water Electrolysis (AWE) system among the heterogeneous water electrolysis systems when renewable energy power is supplied through the control unit, if the predicted value of the renewable energy generation amount is greater than or equal to a preset reference value, and if the predicted value of the renewable energy generation amount is less than a preset reference value, to supply power to the water electrolysis systems excluding the Alkaline Water Electrolysis (AWE) system.

Description

Technology Field

[0001] The present invention relates to a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof. More specifically, it relates to a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof that predicts the amount of renewable energy (Off-grid) produced through an eco-friendly power generation system and switches and supplies power according to the amount of power generated to an AEM and PEM type water electrolysis system with a relatively low minimum load or an AWE type water electrolysis system with a relatively high minimum load but a high hydrogen production capacity. Background Technology

[0002] A water electrolysis system is a system that produces hydrogen and oxygen by electrolyzing water. While such systems are generally configured to be powered on-grid through an external power grid like KEPCO, development is currently underway to efficiently produce hydrogen by configuring them to be powered off-grid through eco-friendly power generation systems.

[0003] As prior art for the above purpose, the hybrid green hydrogen production system and method of operation thereof disclosed in Published Patent Application No. 2024-0155815 (hereinafter referred to as the 'Patent Document') is disclosed.

[0004] The above patent document describes a power generation unit that generates power using a new and renewable energy source; an energy storage unit that stores electrical energy produced by the power generation unit and performs auto-balancing during normal operation; a hydrogen production unit that produces hydrogen using the electrical energy produced by the power generation unit; a hydrogen storage unit that stores hydrogen produced by the hydrogen production unit; a fuel cell unit that produces electrical energy by combining hydrogen and oxygen stored in the hydrogen storage unit; and a selection unit that selectively supplies electrical energy produced by the power generation unit to the energy storage unit and the hydrogen production unit, wherein the selection unit comprises a power input unit that receives power produced by the power generation unit; a charge state detection unit that detects the charge state of the energy storage unit; an information input unit that inputs information on the power generation duration; and a control unit that determines the charge state information of the energy storage unit input through the charge state detection unit and the input information of the information input unit, and performs control according to the determination result. The distribution unit includes a power input unit that distributes power input through the power input unit to the energy storage unit and the hydrogen production unit according to the control of the control unit, wherein when the charging ratio of the energy storage unit is greater than or equal to a first reference value, the electrical energy of the power production unit is supplied only to the hydrogen production unit, and when the power generation sustainability time information input through the information input unit is checked and the charging ratio of the energy storage unit is insufficient as reserve power but there is a possibility that the power currently produced by the power production unit will continue to be produced for more than a set time, the electrical energy of the power production unit is distributed and supplied to both the hydrogen production unit and the energy storage unit to secure sufficient hydrogen energy when the charging ratio of the energy storage unit is less than the first reference value and greater than or equal to a second reference value, and the electrical energy of the power production unit is distributed to both the hydrogen production unit and the energy storage unit according to the sustainability of power production by the power production unit determined by information from a weather forecasting agency.Depending on the degree to which the charge state of the energy storage unit is close to the first reference value or the second reference value, the power from the power production unit supplied to the hydrogen production unit is distributed differentially. If the charge ratio of the energy storage unit is less than the second reference value, all electrical energy from the power production unit is supplied to the energy storage unit. The energy storage unit includes a plurality of battery units, and the battery units are classified into a charging group or a discharging group according to the initial voltage value. In a charging mode, the charging group performs charging, and in a discharging mode, the discharging group performs discharging, thereby performing charging or discharging operations and performing auto-balancing. The auto-balancing is performed without a direct processing step for auto-balancing, but by grouping all batteries within the safe voltage reference range to charge or discharge while performing normal operation according to the operation mode of the energy storage unit based on the operation of the power production unit and the power exchange grid. The processor of the power conversion unit, which includes a DC / DC converter, a DC / AC converter, and a processor, identifies a specific battery having the highest voltage and a battery having the lowest voltage among all batteries in the battery unit, and designates them as the maximum voltage battery and the minimum voltage battery, respectively. Subsequently, all other batteries are checked to identify batteries within the maximum voltage range and set safety voltage range, and group them into a discharge group; and identify batteries within the minimum voltage range and set safety voltage range, and group them into a charge group, thereby preventing overcharging or over-discharging when the batteries belonging to each group are charged or discharged simultaneously.

[0005] However, the aforementioned patent document describes a method in which electricity produced by a power generation unit or electricity from a power exchange is stored in an energy storage unit, and the electricity stored in the energy storage unit is supplied to a hydrogen production unit. Although the system is controlled to supply electricity through the optimal battery based on the charge and discharge status of multiple batteries, this method aims solely to supply electricity to the hydrogen production unit without considering changes in the power generation amount of the power generation unit or the electricity rates of the power exchange. Consequently, there is a problem in that it is difficult to maximize the utilization of renewable energy or reduce the unit cost of hydrogen production.

[0006] In addition, there is a problem in stably supplying power to the water electrolysis system due to reduced power generation at nuclear and thermal power plants and the intermittent operation of eco-friendly power generation systems.

[0007] In addition, since conventional water electrolysis systems are installed using a single method, it is difficult to operate the system efficiently in response to load fluctuations caused by renewable energy generation.

[0008] Therefore, there is a need to develop an improved water electrolysis system and a control method thereof that can accurately predict renewable energy generation using weather information and simultaneously increase the efficiency of hydrogen production using renewable energy by selectively supplying power to different water electrolysis systems based on the predicted generation value, while also significantly reducing grid power usage by storing excess power in an energy storage device when the predicted generation value exceeds the power consumption. Prior art literature

[0009] KR 10-2024-0155815 A (2024. 10. 29.)KR 10-2024-0167746 A (2024. 11. 28.)KR 10-2024-0099082 A (2024. 06. 28.)KR 10-2331300 B1 (November 22, 2021) The problem to be solved

[0010] The present invention was devised to solve the problems of the conventional water electrolysis system as described above. The problem to be solved by the present invention is to provide a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof, which predicts the amount of renewable energy generated using real-time weather data and switches power according to the predicted amount of generation to an AEM and PEM type water electrolysis system with a relatively low minimum load or an AWE type water electrolysis system with a relatively high minimum load but a high hydrogen production capacity.

[0011] Furthermore, the present invention provides a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof, which can achieve stability and lower hydrogen production costs by storing renewable energy in an energy storage device as needed according to the predicted value of renewable energy generation and supplying grid power supplied through an external power grid to the water electrolysis system. means of solving the problem

[0012] A heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention for solving the above problem comprises: an eco-friendly power generation system comprising one or more selected from wind, solar, wave, and tidal power generation to produce renewable energy power; an external power grid supplying external grid power; an energy storage device that selectively stores power applied from the eco-friendly power generation system; a heterogeneous water electrolysis system comprising one or more selected from an AEM (Anion Exchange Membrane Electrolysis) system and a PEM (Proton Exchange Membrane Electrolysis) system and an AWE (Alkaline Water Electrolysis) system, while power is applied through the eco-friendly power generation system, the external power grid, and the energy storage device; and a power prediction and supply unit that controls the application of power from any one of the eco-friendly power generation system, the external power grid, and the energy storage device to the heterogeneous water electrolysis system, provided that the power meets preset conditions. and includes a power distributor that distributes and supplies power supplied through the power prediction and supply unit to the heterogeneous water electrolysis system, wherein the power prediction and supply unit comprises: a renewable energy generation amount prediction unit that predicts the renewable energy generation amount produced through the eco-friendly power generation system based on real-time weather data from the Korea Meteorological Administration; an external power information collection unit that collects real-time power rate information of grid power supplied through the external power grid and information on the supply and demand status of grid power; an energy storage device status detection unit that detects the charge rate (SOC), charge / discharge state (SOH), power status (SOP), and temperature status of the energy storage device; and a power supply switching unit that causes any one of the renewable energy, grid, and energy storage device selected to be supplied to the heterogeneous water electrolysis system.The system includes a control unit that controls the operation of the power supply switching unit based on information obtained through the renewable energy generation amount prediction unit, the external power information collection unit, and the energy storage device status detection unit, thereby controlling the power supplied to the heterogeneous water electrolysis system. The power distributor is characterized by controlling the supply of power to the AWE (Alkaline Water Electrolysis) system among the heterogeneous water electrolysis systems when renewable energy power is supplied through the control unit, provided that when the renewable energy generation amount prediction value is greater than or equal to a preset reference value, the power distributor supplies power to the AWE (Alkaline Water Electrolysis) system, and when the renewable energy generation amount prediction value is less than the preset reference value, the power distributor supplies power to the water electrolysis systems excluding the AWE (Alkaline Water Electrolysis) system.

[0013] In addition, the control unit of the present invention is further characterized by controlling the load to be set to 20% through an AC / DC converter when power is initially supplied to the AWE (Alkaline Water Electrolysis) system through the power distributor, and then gradually increasing to the target load.

[0014] In addition, the present invention is further characterized by controlling the system so that, during the operation of the heterogeneous water electrolysis system using renewable energy, if the predicted value of the renewable energy generation exceeds the power consumption of the heterogeneous water electrolysis system, the excess power is stored in the energy storage device.

[0015] Meanwhile, the control method of a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention comprises: a renewable energy generation amount collection step of collecting a renewable energy generation amount predicted based on real-time weather data from the Korea Meteorological Administration through a renewable energy generation amount prediction unit of a power prediction supply unit; an external power information collection step of collecting real-time electricity rates and grid power supply and demand information, respectively, through an external power information collection unit of the power prediction supply unit; an energy storage device status detection step of detecting the charge rate (SOC), charge / discharge state (SOH), power status (SOP), and temperature status of an energy storage device through an energy storage device status detection unit of the power prediction supply unit; and a power distribution supply step of comprehensively determining the collected renewable energy generation amount, electricity rates, and energy storage device status, and ensuring that any one of the selected powers among renewable energy power, grid power, and stored power of the energy storage device is distributed to the heterogeneous water electrolysis system or supplied exclusively through a control unit of the power prediction supply unit. The method includes a stepwise load control step that controls the load applied during the initial startup of the heterogeneous water electrolysis system by controlling the AC / DC converter through the control unit, and the power distribution supply step is characterized by controlling the supply of power to the AWE (Alkaline Water Electrolysis) system among the heterogeneous water electrolysis systems when renewable energy power is supplied through the control unit if the predicted value of renewable energy generation is greater than or equal to a preset reference value, and controlling the supply of power to the water electrolysis systems excluding the AWE (Alkaline Water Electrolysis) system if the predicted value of renewable energy generation is less than the preset reference value. Effects of the invention

[0016] According to the present invention, when the predicted value of renewable energy generation is less than a preset reference value, power is applied to PEM and AEM water electrolysis systems with a relatively low minimum load to produce hydrogen, and when the predicted value of renewable energy generation is greater than or equal to a preset reference value, power is applied to AWE water electrolysis systems with a relatively high load and high hydrogen production capacity to produce hydrogen, so there is an advantage of being able to continuously produce hydrogen by efficiently operating the water electrolysis system according to the amount of renewable energy generation.

[0017] In addition, by collecting real-time weather information from the Korea Meteorological Administration to relatively accurately predict the renewable energy generation of the eco-friendly power generation system, and based on this, when renewable energy generation is low, the renewable energy is stored in an energy storage device and then supplied to the heterogeneous water electrolysis system; conversely, when renewable energy generation is high, the renewable energy and the power stored in the energy storage device are supplied to the heterogeneous water electrolysis system instead of the grid power, thereby enabling stable hydrogen production while having the advantage of lowering the production cost of hydrogen. Brief explanation of the drawing

[0018] FIG. 1 is a configuration diagram showing an example of a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention. FIGS. 2 and FIGS. 3 are flowcharts showing a control method for a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention. FIGS. 4 to 6 are enlarged drawings of the flowchart according to FIG. 3. Specific details for implementing the invention

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0020] The present invention aims to provide a heterogeneous water electrolysis system based on an on / off grid switching hybrid method and a control method thereof, which can switch power to an AEM and PEM type water electrolysis system with a relatively low minimum load or an AWE type water electrolysis system with a relatively high minimum load but a high hydrogen production capacity, depending on the predicted value of renewable energy generation. As shown in FIG. 1, the present invention includes an eco-friendly power generation system (1), an external power grid (2), an energy storage device (3), a heterogeneous water electrolysis system (4), a power prediction supply unit (5), and a power distributor (PD).

[0021] The eco-friendly power generation system (1) is configured to produce renewable energy power by being composed of one or more selected from wind power, solar power, wave power, and tidal power generation. The eco-friendly power generation system (1) can be configured by selecting from various known types of eco-friendly power generation systems to facilitate implementation by a person skilled in the art, and accordingly, a detailed description of the configuration of the eco-friendly power generation system (1) is omitted.

[0022] Meanwhile, renewable energy produced through the eco-friendly power generation system (1) is configured to be selectively supplied to an energy storage device (3) or a heterogeneous water electrolysis system (4) through the power prediction supply unit (5) described later.

[0023] The external power grid (2) is external system power supplied through the Korea Electric Power Corporation, the Korea Power Exchange, nuclear power plants, thermal power plants, etc., and this external power grid (2) is configured to selectively supply to the heterogeneous water electrolysis system (4) according to real-time power rate information and information on the supply and demand status of system power collected through the power prediction and supply unit (5) described later.

[0024] The energy storage device (3) is configured to selectively store power supplied from the eco-friendly power generation system (1) and to selectively supply the stored power to the heterogeneous water electrolysis system (4) by the power prediction supply unit (5).

[0025] As shown in FIG. 1, this energy storage device (3) is configured such that renewable energy produced in an eco-friendly power generation system (1) passes through a transformer (6) to convert the input voltage to a set voltage, and then passes through a power conversion device (7, PCS) to improve the quality of the power, and then is charged into the energy storage device (3).

[0026] At this time, the energy storage device (3) is monitored in real time for the state of charge (SOC), state of health (SOH), state of power (SOP), and temperature through the power prediction supply unit (5) described later, and thereby prevents the energy storage device (3) from being discharged or overcharged.

[0027] Although it was described above that the status of the energy storage device (3) is detected in real time through the power prediction supply unit (5), it can be changed so that real-time status information is transmitted to the power prediction supply unit (5) through the BMS (Battery Management System) installed in the energy storage device (3).

[0028] The heterogeneous water electrolysis system (4) is configured such that power is supplied from one or more selected from an eco-friendly power generation system (1), an external power grid (2), and an energy storage device (3) by the selection of the power prediction supply unit (5), and through this, water (electrolyte) is electrolyzed to produce hydrogen and oxygen.

[0029] The water electrolysis stack of this heterogeneous water electrolysis system (4) is formed in a stacked form of multiple cells including an anode electrode (not shown), a cathode electrode (not shown), a membrane (not shown), a separator (not shown), an end plate (not shown), and a gasket (not shown), and the hydrogen and oxygen generated through the water electrolysis stack pass through a pre-filter (not shown), a gas-liquid separator, etc., so that the hydrogen and oxygen are separated from the water (electrolyte), and then the hydrogen is purified to a high purity and stored.

[0030] And the heterogeneous water electrolysis system (4) is configured to include an AWE (Alkaline Water Electrolysis) system (4A) in one or more systems selected from the publicly known and widely known PEM (Proton Exchange Membrane Electrolysis) system (4B) and AEM (Anion Exchange Membrane Electrolysis) system (4C).

[0031] Here, the AWE system (4A) has the disadvantage of a relatively high minimum load level that can be operated, but has the advantage of being able to produce large volumes and stable hydrogen, while the PEM system (4B) and AEM system (4C) have the advantage of a relatively low minimum load level that can be operated, but have the disadvantage of being expensive and having a small unit stack capacity.

[0032] Accordingly, the heterogeneous water electrolysis system (4) according to the present invention can produce hydrogen at a relatively low load by supplying power to the PEM system (4B) and AEM system (4C), which have a relatively lower minimum load level, when the predicted value of renewable energy generation falls short of the minimum load level of the AWE system (4A), and by supplying power to the AWE system (4A) to produce hydrogen when the predicted value of renewable energy generation matches the minimum load level of the AWE system (4A), thereby enabling efficient control of the standby, operation, and shutdown of the heterogeneous water electrolysis system (4) according to the predicted value of renewable energy generation.

[0033] Meanwhile, the power supplied to the heterogeneous water electrolysis system (4) is configured such that the voltage input through the transformer (6) is converted to match a preset voltage, and then passes sequentially through the AC / DC converter (8) and the rectifier (9) to be applied to the heterogeneous water electrolysis system (4). At this time, the AC / DC converter (8) is configured such that the load rate is controlled to match a preset ratio through the control unit (50) of the power prediction supply unit (5) described later.

[0034] The power prediction supply unit (5) is configured to control the application of power from one of the following sources—an eco-friendly power generation system (1), an external power grid (2), and an energy storage device (3)—to the heterogeneous water electrolysis system (4) to meet pre-set conditions (e.g., economic efficiency, renewable energy utilization rate, operational sustainability, safety, etc.), thereby maximizing the use of renewable energy and thereby lowering the hydrogen production cost to increase economic efficiency.

[0035] This power prediction and supply unit (5) may be composed of a control device including a processor, memory, and a communication module, and furthermore, as shown in FIG. 1, the power prediction and supply unit (5) comprises a renewable energy generation amount prediction unit (10) that predicts the amount of renewable energy generated through an eco-friendly power generation system (1) based on real-time weather data from the Korea Meteorological Administration, an external power information collection unit (20) that collects real-time power rate information of grid power supplied through an external power grid (2) and information on the supply and demand status of grid power, an energy storage device status detection unit (30) that detects the charge rate (SOC), charge / discharge state (SOH), power status (SOP), and temperature state of an energy storage device (3), a power supply switching unit (40) that causes one of the power selected from renewable energy, grid, and energy storage device to be supplied to a heterogeneous water electrolysis system (4), and the power supply based on the information obtained through the renewable energy generation amount prediction unit (10), the external power information collection unit (20), and the energy storage device status detection unit (30). It may be configured to include a control unit (50) that controls the power supplied to the heterogeneous water electrolysis system (4) by controlling the operation of the switching unit (40).

[0036] At this time, the renewable energy generation amount prediction unit (10) obtains weather information from the weather agency in real time via the internet and predicts the amount of power generated by the eco-friendly power generation system (1) according to the weather conditions. As the actual power generation amount data and weather information such as temperature, humidity, date, time, wind direction and wind speed are accumulated and stored in this renewable energy generation amount prediction unit (10), the error between the actual renewable energy generation amount and the predicted amount is continuously corrected, and as a result, the accuracy of the renewable energy generation amount prediction naturally improves as the operating time progresses, and the predicted renewable energy generation amount prediction value is transmitted in real time to the control unit (50).

[0037] In addition, the external power information collection unit (20) collects real-time information on the comparison of electricity rates by time of day and the power supply and demand status (reduced generation) of the external power grid (2) supplied through KEPCO, the Korea Power Exchange, nuclear power plants, thermal power plants, etc., and transmits it to the control unit (50).

[0038] And the energy storage device status detection unit (30) monitors the charge rate (SOC), charge / discharge status (SOH), power status (SOP), and temperature status of the energy storage device (3) in real time, and the detected information is transmitted to the control unit (50) in real time.

[0039] Meanwhile, the control unit (50) receives the predicted renewable energy generation amount predicted through the renewable energy generation amount prediction unit (10), real-time power rate and power supply status information collected through the external power information collection unit (20), and the charging rate (SOC), charging / discharging status (SOH), power status (SOP), and temperature information of the energy storage device (3) detected through the energy storage device status detection unit (30), and calculates the power cost required for unit hydrogen production in real time based on the various information received, and controls the switching operation of the power supply switching unit (40) so that the power with the minimum cost is selected and supplied to the heterogeneous water electrolysis system (4).

[0040] At this time, the control unit (50) can control the preheating operation to be performed before reaching rated operation when the predicted value of renewable energy generation is greater than or equal to the set standard, and more specifically, the control unit (50) can control the AC / DC converter (8) so that the load is increased stepwise according to the temperature, pressure, time, or gas concentration standard of the electrolyte during the initial startup of the heterogeneous water electrolysis system (4).

[0041] This prevents abnormal behavior of the system and shock (thermal shock, etc.) to the components that occur when the normal operating load is input while the temperature of the electrolyte is lower than the normal operating temperature during the initial startup of the heterogeneous water electrolysis system (4).

[0042] Additionally, the control unit (50) can control the excess power to be stored in the energy storage device (3) when the predicted value of renewable energy generation is greater than the power consumption of the heterogeneous water electrolysis system (4), and, conversely, when the predicted value of renewable energy generation is less than the power consumption of the heterogeneous water electrolysis system (4), control the power stored in the energy storage device (3) to be supplied to the heterogeneous water electrolysis system (4) as a primary power, and then control the grid power supplied from the external power grid (2) to be supplied as a secondary power.

[0043] Through this, it becomes possible to stably supply power to the heterogeneous water electrolysis system (4) even if continuous power generation and power output of the eco-friendly power generation system (1) are not guaranteed, and at the same time, hydrogen can be produced at a relatively low cost, and as a result, the production cost of hydrogen can be lowered to increase price competitiveness.

[0044] The power distributor (PD) is configured such that when power is supplied to a heterogeneous water electrolysis system (4) according to the predicted renewable energy generation amount predicted by the power prediction supply unit (5), the predicted renewable energy generation amount is additionally compared with a secondary reference value (e.g., 25%), and in this process, if the predicted renewable energy generation amount is greater than or equal to the secondary reference value, power is supplied to the AWE system (4A), and if the predicted renewable energy generation amount is less than the secondary reference value, power is distributed and supplied to the AEM system (4B) and / or PEM system (4C).

[0045] This power distributor (PD) can be configured so that the reference value is changed remotely through the control unit (50) of the power supply unit (5).

[0046] Hereinafter, a control method for a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention will be described in detail.

[0047] The control method of a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to the present invention is performed through a power prediction supply unit (5) and a power distributor (PD). First, the control unit (50) collects real-time weather information through the meteorological agency as shown in FIGS. 2 and 3, and predicts the amount of renewable energy generated by the eco-friendly power generation system (1) based on this (renewable energy generation amount collection step (S10)).

[0048] Then, the control unit (50) collects information on real-time electricity rates and power supply and demand status of external power systems, such as KEPCO, the Korea Power Exchange, nuclear power plants, and thermal power plants, through the external power information collection unit (20) (external power information collection step (S20)).

[0049] Afterwards, the control unit (50) determines whether the predicted value of renewable energy generation is greater than or equal to a preset reference value (e.g., 20%) as shown in FIG. 4, and if the predicted value of renewable energy generation is less than the reference value, determines whether the power stored in the energy storage device (3) is greater than or equal to a reference value (e.g., 80%).

[0050] At this time, if the power stored in the energy storage device (3) is greater than or equal to a reference value, the power stored in the energy storage device (3) is supplied to the heterogeneous water electrolysis system (4), and if it is less than a reference value, the grid power is controlled to be supplied to the heterogeneous water electrolysis system (4) through the external power grid (2).

[0051] In contrast, if the predicted value of renewable energy generation is greater than or equal to the reference value, the charging amount (charging state) of the energy storage device (3) transmitted through the energy storage device status detection unit (30) is determined to be greater than or equal to a preset reference value (e.g., 80%) (energy storage device status detection step (S30)).

[0052] At this time, if the charge amount of the energy storage device (3) is less than a preset reference value, renewable energy power is supplied to the energy storage device (3) to charge the energy storage device (3), and then the energy storage device (3) is stored and then determined again whether the predicted value of renewable energy generation is greater than or equal to the reference value.

[0053] In addition, when the charge amount of the energy storage device (3) is greater than or equal to a preset reference value, it is determined whether the predicted value of renewable energy generation is greater than or equal to the reference value (e.g., 20%), and if it is greater than or equal to the reference value, the power is supplied to the heterogeneous water electrolysis system (4), and if it is less than the reference value, it returns to the starting step and determines again whether the predicted value of renewable energy generation is greater than or equal to the reference value.

[0054] Through the above process, based on the predicted value of renewable energy generation, the power to be supplied to the heterogeneous water electrolysis system (4) is supplied to the heterogeneous water electrolysis system (4) in order of priority among renewable energy power, energy storage device power, and grid power, with the power having a lower hydrogen production cost.

[0055] Afterwards, the control unit (50) determines whether the predicted value of renewable energy generation is greater than or equal to a preset secondary reference value (e.g., 25%) when the power supplied to the heterogeneous water electrolysis system (4) is renewable energy.

[0056] At this time, if the predicted value of renewable energy generation is greater than or equal to the second reference value, power is controlled to be supplied to the AWE system (4A) through the power distributor (PD), whereas if the predicted value of renewable energy generation is less than the second reference value, power is controlled to be supplied to the AEM system (4B) and / or PEM system (4C) through the power distributor (PD).

[0057] Here, when power is initially supplied to the AWE system (4A), as shown in FIG. 5, the control unit (50) controls the AC / DC converter (8) to a 20% load rate and then checks that the pressure of the oxygen (O2) gas separator is greater than or equal to the set pressure (H) (step load control step (S50)).

[0058] Additionally, when power is supplied to the AEM system (4B) and / or PEM system (4C), instead of controlling the AC / DC converter (8) at a 20% load rate, it is immediately checked that the pressure of the oxygen (O2) gas separator is above the set pressure (H).

[0059] And when the pressure of the oxygen gas separator is below the set pressure (H), the control state is maintained until it becomes above the set pressure (H), and when it is above the set pressure (H), the hydrogen sampling valve is opened, the oxygen sampling valve is opened, the hydrogen discharge valve is closed, the oxygen discharge valve is closed, and the oxygen discharge valve pressure is controlled, while simultaneously determining whether the predicted value of the renewable energy generation is greater than the power consumption.

[0060] At this time, if the predicted value of renewable energy generation is greater than the power consumption, the excess power is switched to be charged into the energy storage device (3) and the hydrogen production process is started. On the other hand, if the predicted value of renewable energy generation is less than the power consumption, the power of the energy storage device is supplied and then the hydrogen production process is started.

[0061] Subsequently, it is determined again whether the supplied power, including renewable energy and energy storage power, is greater than or equal to the consumed power; if the supplied power is less than the consumed power, grid power is supplied.

[0062] In addition, if the power supply is greater than the power consumption or if grid power is supplied, the AC / DC converter (8) is controlled at a load rate of 30% as shown in FIG. 6, and then it is checked whether the concentration of hydrogen and oxygen analyzers is greater than or equal to the set allowable upper limit (H).

[0063] At this time, if the concentration of the hydrogen and oxygen analyzer is greater than or equal to the set allowable upper limit (H), it is maintained until it is less than the allowable upper limit (H), and if the concentration of the hydrogen and oxygen analyzer is less than the set allowable upper limit (H), the AC / DC converter (8) is controlled at a load rate of 60%.

[0064] Then, when operation continues at a 60% load rate and a set time (e.g., 15 minutes) has elapsed, the AC / DC converter (8) is controlled to a 100% load rate to switch to a normal operation mode, and then hydrogen is continuously produced while checking the flow rate of hydrogen.

[0065] As explained above, the present invention produces hydrogen by applying power to a PEM and AEM type water electrolysis system with a relatively low minimum load when the predicted value of renewable energy generation is below a preset reference value, and produces hydrogen by applying power to an AWE type water electrolysis system with a relatively high load and high hydrogen production when the predicted value of renewable energy generation is above a preset reference value, thereby enabling the continuous production of hydrogen by efficiently operating the water electrolysis system according to the amount of renewable energy generation.

[0066] In addition, by collecting real-time weather information from the Korea Meteorological Administration to relatively accurately predict the renewable energy generation of the eco-friendly power generation system, if the renewable energy generation is low, the renewable energy is stored in an energy storage device and then supplied to the electrolysis system using grid power; conversely, if the renewable energy generation is high, the renewable energy and power stored in the energy storage device are supplied to the electrolysis system instead of grid power, thereby enabling stable hydrogen production while lowering the production cost of hydrogen.

[0067] In addition, since the load for each system increases in stages during the initial startup of the water electrolysis system, abnormal behavior and stack damage occurring during the initial startup are prevented.

[0068] For the convenience of explanation, drawings illustrating preferred embodiments and configurations shown in the drawings have been described above using reference numerals and names; however, as this is merely one embodiment according to the present invention, the scope of the rights should not be interpreted as being limited to the shapes shown in the drawings and the names assigned thereto. It is considered entirely obvious that modifications to various shapes predictable from the description of the invention and simple substitutions with configurations having the same function fall within the scope of modifications that a person skilled in the art can easily implement. Explanation of the symbols

[0069] 1: Eco-friendly power generation system 2: External power grid 3: Energy Storage Device 4: Heterogeneous Water Electrolysis System 4A: AWE System 4B: AEM System 4C: PEM System 5: Power Forecasting Supply Unit 6: Transformer 7: Power converter 8: AC / DC converter 9: Rectifier 10: Renewable Energy Generation Prediction Unit 20: External Power Information Collection Unit 30: Energy storage device status detection unit 40: Power supply switching unit 50: Control unit PD: Power distributor

Claims

Claim 1 An eco-friendly power generation system (1) that produces renewable energy power by being composed of one or more selected from wind power, solar power, wave power, and tidal power generation; an external power grid (2) that supplies external grid power; an energy storage device (3) that selectively stores power supplied from the eco-friendly power generation system (1); a heterogeneous water electrolysis system (4) that includes one or more selected from an Anion Exchange Membrane Electrolysis (AEM) system (4B) and a Proton Exchange Membrane Electrolysis (PEM) system (4C) and an Alkaline Water Electrolysis (AWE) system (4A) while power is supplied through the eco-friendly power generation system (1), the external power grid (2), and the energy storage device (3); and a power prediction supply unit (5) that controls power supplied to the heterogeneous water electrolysis system (4) by ensuring that any one of the eco-friendly power generation system (1), the external power grid (2), and the energy storage device (3) meets preset conditions. The power distribution unit (PD) that distributes and supplies power supplied through the power prediction supply unit (5) to the heterogeneous water electrolysis system (4); wherein the power prediction supply unit (5) includes: a renewable energy generation amount prediction unit (10) that predicts the renewable energy generation amount produced through the eco-friendly power generation system (1) based on real-time weather data from the Korea Meteorological Administration; an external power information collection unit (20) that collects real-time power rate information of the grid power supplied through the external power grid (2) and information on the supply and demand status of the grid power; an energy storage device status detection unit (30) that detects the charge rate (SOC), charge / discharge state (SOH), power status (SOP), and temperature state of the energy storage device (3); and a power supply switching unit (40) that causes any one of the power selected from the renewable energy, grid, and energy storage device to be supplied to the water electrolysis system (4).A control unit (50) that controls the operation of the power supply switching unit (40) based on information obtained through the renewable energy generation amount prediction unit (10), the external power information collection unit (20), and the energy storage device status detection unit (30), thereby controlling the power supplied to the heterogeneous water electrolysis system (4); wherein the power distributor (PD) controls the supply of power to the AWE (Alkaline Water Electrolysis) system (4A) among the heterogeneous water electrolysis systems (4) when renewable energy power is supplied through the control unit (50) if the renewable energy generation amount prediction value is greater than or equal to a preset reference value, and controls the supply of power to the water electrolysis systems excluding the AWE (Alkaline Water Electrolysis) system (4A) if the renewable energy generation amount prediction value is less than the preset reference value, wherein the on / off grid switching-based hybrid heterogeneous water electrolysis system, based on real-time weather data from the Korea Meteorological Administration through the renewable energy generation amount prediction unit (10) of the power prediction supply unit (5). A renewable energy generation amount collection step (S10) for collecting predicted renewable energy generation amount; an external power information collection step (S20) for collecting real-time power rates and grid power supply and demand information, respectively, through an external power information collection unit (20) of the power prediction supply unit (5); an energy storage device status detection step (S30) for detecting the charge rate (SOC), charge / discharge state (SOH), power status (SOP), and temperature state of the energy storage device (3) through an energy storage device status detection unit (30) of the power prediction supply unit (5); and a power distribution supply step (S40) for comprehensively determining the collected renewable energy generation amount, power rates, and energy storage device status, and for distributing or supplying exclusively any one of the selected powers among renewable energy power, grid power, and stored power of the energy storage device through a control unit (50) of the power prediction supply unit (5).A control method for a heterogeneous water electrolysis system based on an on / off grid switching hybrid type, comprising: a stepwise load control step (S50) for controlling the AC / DC converter (8) through the control unit (50) to control the load applied during the initial startup of the water electrolysis system (4) in steps; wherein the power distribution supply step (S40) is characterized by controlling the supply of power to the AWE (Alkaline Water Electrolysis) system (4A) among the heterogeneous water electrolysis systems (4) when renewable energy power is supplied through the control unit (50) if the predicted value of renewable energy generation is greater than or equal to a preset reference value, and controlling the supply of power to the water electrolysis systems excluding the AWE (Alkaline Water Electrolysis) system (4A) if the predicted value of renewable energy generation is less than the preset reference value. Claim 2 A control method for a heterogeneous water electrolysis system based on an on / off grid switching hybrid method according to claim 1, wherein the control unit (50) controls the load to be set to 20% through the AC / DC converter (8) when power is initially supplied to the AWE (Alkaline Water Electrolysis) system (4A) through the power distributor (PD), and then increases the load in stages to match the target load. Claim 3 A control method for an on / off grid switching-based hybrid type heterogeneous water electrolysis system according to claim 1, wherein the control unit (50) controls the system so that, when the predicted value of the renewable energy generation amount is greater than or equal to the power consumption of the heterogeneous water electrolysis system (4) during operation of the heterogeneous water electrolysis system (4) using renewable energy power, the excess power is stored in the energy storage device (3). Claim 4 delete

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