CN114447968A - Large-scale photovoltaic electrolyzed water hydrogen production system and method utilizing hybrid energy storage device - Google Patents
Large-scale photovoltaic electrolyzed water hydrogen production system and method utilizing hybrid energy storage device Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/14—Balancing the load in a network
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/342—The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
Abstract
The large-scale photovoltaic electrolyzed water hydrogen production system and method utilizing the hybrid energy storage device comprise a photovoltaic power generation device, wherein the output end of the photovoltaic power generation device is electrically connected with a DC-DC Boost converter, the output end of the DC-DC Boost converter is electrically connected with an electrolytic bath, two energy storage devices which are connected in parallel are connected on a direct current bus between the DC-DC Boost converter and the electrolytic bath, each energy storage device comprises an energy type energy storage device and a power type energy storage device, the energy type energy storage devices are connected with the direct current bus through a first DC-DC converter, and the power type energy storage devices are connected with the direct current bus through a second DC-DC converter. The invention fully considers the characteristics of energy type and power type energy storage devices, reasonably distributes high-frequency components and low-frequency components of power fluctuation, plays a role in relieving the service life of the energy type battery, and has the advantages of stability, economy and high efficiency.
Description
Technical Field
The invention belongs to the technical field of hydrogen production by electrolyzing water by using renewable energy sources, and particularly relates to a large-scale photovoltaic hydrogen production system by electrolyzing water by using a hybrid energy storage device and a method thereof.
Background
The hydrogen production by electrolyzing water by renewable energy is a key technology for converting the renewable energy, can be used as a variable load to carry out peak clipping and valley filling to improve the power generation online quality of the renewable energy, can effectively consume abandoned wind, abandoned light and abandoned water to improve the utilization rate of the renewable energy, and is an effective means for the consumption of the renewable energy. Meanwhile, the water electrolysis hydrogen production technology is green and environment-friendly, has low carbon emission, flexible production and high purity, is regarded as the most potential hydrogen production technology in the future, and is expected by various circles.
A traditional renewable energy water electrolysis hydrogen production system is generally composed of renewable energy sources (wind power and photovoltaic), a converter and an electrolytic cell. Due to the intermittent and random characteristics of renewable energy sources such as wind energy, solar energy and the like for hydrogen production by water electrolysis, the hydrogen production system by water electrolysis of renewable energy sources has the problems of unstable system, electric energy waste, low system efficiency and the like. The problem faced by the above can be solved by configuring energy storage in the renewable energy water electrolysis hydrogen production system. Chinese patent application No. 202010887285.0, patent name: a multi-energy complementary wind-light-hydrogen storage integrated renewable energy system provides a wind-electricity, photovoltaic, energy storage and water electrolysis hydrogen production equipment integrated renewable energy system; chinese patent application No. 202021873646.8, patent name: a renewable energy hydrogen production system provides a renewable energy system consisting of renewable energy, energy storage and water electrolysis hydrogen production equipment; the two patents of the invention both add an energy storage device in the application of hydrogen production by renewable energy sources, and play a role in improving the stability of the system. However, in the existing technical solution, only a single energy storage mode (energy type battery) is considered, and the method is suitable for the situation that the fluctuation of the load electrolytic cell and the renewable energy source is not large. And for a large-scale water electrolysis hydrogen production system, the number of the electrolysis baths is large. When the fluctuation of a load (an electrolytic bath) is large, the energy type battery needs frequent charging and discharging, and the quick fluctuation of the load power can cause the response of the battery to be unsmooth in the charging and discharging process, thereby influencing the service life of the energy type battery.
Disclosure of Invention
In view of the technical problems in the background art, the large-scale photovoltaic water electrolysis hydrogen production system and method utilizing the hybrid energy storage device fully consider the characteristics of the energy type and power type energy storage devices, and organically combine the energy type and power type energy storage devices with the photovoltaic water electrolysis hydrogen production system, when the power fluctuation of a photovoltaic system or a hydrogen production load is large and fast, the hybrid energy storage device reasonably distributes the high-frequency component and the low-frequency component of the power fluctuation, the effect of relieving the service life of an energy type battery is achieved, and the system and method have the advantages of stability, economy and high efficiency.
In order to solve the technical problems, the invention adopts the following technical scheme to realize:
a large-scale photovoltaic water electrolysis hydrogen production system utilizing a hybrid energy storage device comprises a photovoltaic power generation device, wherein the output end of the photovoltaic power generation device is electrically connected with a DC-DC Boost converter, the output end of the DC-DC Boost converter is electrically connected with an electrolytic bath, two energy storage devices which are connected in parallel are connected on a direct current bus between the DC-DC Boost converter and the electrolytic bath, each energy storage device comprises an energy type energy storage device and a power type energy storage device, the energy type energy storage devices are connected with the direct current bus through a first DC-DC converter, and the power type energy storage devices are connected with the direct current bus through a second DC-DC converter; the first DC-DC converter is a bidirectional DC-DC converter, the energy type energy storage device is an electrochemical energy storage device, and the power type energy storage device is a super capacitor or a superconducting energy storage device.
In a preferred embodiment, the first DC-DC converter and the DC bus are controlled to be turned on or off by a power electronic switch S4 and a power electronic switch S5, so as to realize bidirectional flow of energy between the DC bus and the energy storage device.
In a preferred embodiment, when the power type energy storage device is a super capacitor, the second DC-DC converter is a bidirectional DC-DC converter, and the second DC-DC converter and the DC bus are controlled to be on or off by a power electronic switch S6 and a power electronic switch S7, so as to realize bidirectional energy flow between the DC bus and the super capacitor;
when the power type energy storage device is a superconducting energy storage device, the second DC-DC converter is a DC-DC chopper, and the connection and disconnection between the DC-DC chopper and the direct current bus are controlled through a power electronic switch S6 and a power electronic switch S7, so that the energy bidirectional flow between the direct current bus and the superconducting energy storage device is realized.
In a preferable scheme, the direct current bus is connected with a power grid through a DC-AC converter, a switch S1 is arranged between the direct current bus and the DC-AC converter, and the power grid is used for realizing the power supply of the power grid to the electrolytic cell when the photovoltaic power generation device and the energy storage device are in failure or insufficient in power.
In a preferable scheme, hydrogen generated by the electrolytic cell is stored by a gas hydrogen storage tank, the hydrogen in the gas hydrogen storage tank is converted into liquid hydrogen by a liquid hydrogen preparation device and is stored by a liquid hydrogen storage tank, the liquid hydrogen storage tank is connected with a Dewar through a liquid conveying pipeline, and the Dewar is connected with the gas hydrogen storage tank through a gas conveying pipeline; the Dewar, the gas transmission pipeline, the liquid hydrogen preparation device, the liquid hydrogen storage tank and the liquid transmission pipeline form a cooling system, and the cooling system is used for refrigerating the magnet of the superconducting energy storage device.
In a preferred scheme, the operation method of the large-scale photovoltaic water electrolysis hydrogen production system utilizing the hybrid energy storage device comprises the following steps:
parameter definition: the power of the photovoltaic power generation device is P1, the energy type energy storage device and the power type energy storage device form a hybrid energy storage device, the power of the hybrid energy storage device is P2= P3+ P4, wherein P3 is the power of the energy type energy storage device, P4 is the power of the power type energy storage device, P5 is the power of the hydrogen production device by water electrolysis, and P6 is the power of a power grid;
the operation method comprises the following conditions:
case 1: the operation mode comprises the following modes in daytime but not in cloudy days:
1) when P1 is larger than P5, the switch S1 between the power grid and the direct current bus is in an off state, and the photovoltaic power generation device supplies power to the hybrid energy storage device and the electrolytic cell at the same time; at the moment, the energy type energy storage device and the power type energy storage device are in a charging state until the energy type energy storage device and the power type energy storage device are charged to a set target SOC threshold value; the energy type energy storage device bears the low-frequency part of the power fluctuation, and the power type energy storage device bears the high-frequency part of the power fluctuation;
2) when P1 is less than P5 and P1+ P2 is more than P5, the switch S1 between the power grid 6 and the direct current bus is still in an off state, and the photovoltaic power generation device and the hybrid energy storage device supply power to the electrolytic cell at the same time; at the moment, the energy type energy storage device and the power type energy storage device are in a discharge state, the energy type energy storage device bears the low-frequency part of power fluctuation, and the power type energy storage device bears the high-frequency part of the power fluctuation;
3) when P1 is more than P5 and P1+ P2 is more than P5, the switch S1 between the power grid and the direct-current bus is in a closed state, and the power grid and the photovoltaic power generation device simultaneously supply power to the hybrid energy storage device and the electrolytic cell until the hybrid energy storage device is charged to the target SOC threshold value; at the moment, the energy type energy storage device and the power type energy storage device are in a charging state; the energy type energy storage device bears the low-frequency part of the power fluctuation, and the power type energy storage device bears the high-frequency part of the power fluctuation;
case 2: at night or on cloudy days, the operation mode comprises the following modes:
1) when P2 is larger than P5, the switch S1 between the power grid and the direct current bus is in an off state, the mixed energy storage device supplies power to the electrolytic cell, the energy type energy storage device bears the low-frequency part of power fluctuation, and the power type energy storage device bears the high-frequency part of the power fluctuation;
2) when P2 is less than P5, the switch S1 between the power grid and the direct-current bus is in a closed state, and the power grid supplies power to the electrolytic cell and the hybrid energy storage device until the battery is charged to the target SOC threshold value; the energy storage device assumes the low frequency portion of the power fluctuation, and the power storage device assumes the low frequency portion of the power fluctuation.
In a preferred scheme, when the power type energy storage device is superconducting energy storage, hydrogen generated by the electrolytic cell is directly stored in the gas hydrogen storage tank, the gas hydrogen in the gas hydrogen storage tank is converted into liquid hydrogen through the liquid hydrogen preparation device and is stored in the liquid hydrogen storage tank, and the conversion of the gas hydrogen and the liquid hydrogen in the Dewar is realized through the gas transmission pipeline and the liquid transmission pipeline and is used for refrigerating the superconducting energy storage magnet, so that the recycling of the superconducting energy storage and the hydrogen energy is realized; the gas pipeline and the liquid conveying pipeline are respectively provided with a program controllable switch valve for controlling the intellectualization of liquid hydrogen input and gas hydrogen output; a liquid hydrogen displacement measurement sensing device, a gas hydrogen concentration measurement sensing device and a Dewar internal pressure measurement sensing device are arranged in the Dewar; the method comprises the steps of adopting a central controller to collect signals measured by a liquid hydrogen displacement measurement sensing device, a gas hydrogen concentration measurement sensing device and a Dewar internal pressure measurement sensing device in real time, and controlling the on and off of program controllable switch valves on a gas pipeline and a liquid pipeline through the comparison of the measurement signals and reference signals, thereby realizing the intelligent cyclic utilization of hydrogen and liquid hydrogen of the superconducting energy storage system.
In a preferred scheme, the control mode of the energy type energy storage device is as follows: the measured direct current bus voltage Vd and the direct current bus reference voltage Vd _ ref are compared through a first comparator and input into a first PI controller to obtain reference current Iref; the first PI controller carries out frequency division processing on the reference current Iref to realize frequency division control of the energy type energy storage device and the power type energy storage device; ib _ ref output by the reference current Iref through the low-pass filter is a low-frequency component of the reference current Iref, and Ib _ ref is compared with the measured current Ib of the energy type energy storage device through a second comparator and is input into a second PI controller, and the second PI controller controls the conduction and the disconnection of a power electronic switch S4 and a power electronic switch S5 of the bidirectional first DC-DC converter between the energy type energy storage device and the direct-current bus;
the control mode of the power type energy storage device is as follows: the reference current Iref subtracts the low-frequency component of Ib _ ref through the third comparator to obtain the high-frequency component Ic _ ref of the reference current Iref, Ic _ ref is compared with the measured current Ic of the power type energy storage device through the fourth comparator and is input into the third PI controller, and the third PI controller output of the third PI controller controls the on and off of the power electronic switch S6 and the power electronic switch S7 of the second DC-DC converter between the power type energy storage device and the DC bus.
This patent can reach following beneficial effect:
1. the hybrid energy storage device is added into the large-scale photovoltaic electrolyzed water hydrogen production system, the system operation mode and the control mode are reasonably designed, the fluctuation and the instability of the large-scale photovoltaic electrolyzed water hydrogen production system are improved, and the service life of the energy type energy storage device is prolonged;
2. in a large-scale photovoltaic water electrolysis hydrogen production system, a superconducting energy storage device and an energy type energy storage device are organically combined, and a high-temperature superconducting energy storage magnet is cooled by utilizing the cyclic conversion between hydrogen and liquid hydrogen, so that the comprehensive utilization of hydrogen energy and a high-temperature superconducting hybrid energy storage technology is realized, and the waste of the hydrogen energy and the high maintenance cost required by the traditional refrigeration mode of the magnet during the online operation of the high-temperature superconducting energy storage are avoided.
Drawings
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
FIG. 1 is a general diagram of a renewable energy water electrolysis hydrogen production system based on a hybrid energy storage device in the invention;
FIG. 2 is a topological diagram of a renewable energy water electrolysis hydrogen production system based on the hybrid energy storage of a lithium ion battery and a super capacitor according to the present invention when the energy type energy storage device and the power type energy storage device are the lithium ion battery and the super capacitor, respectively;
FIG. 3 is a topological diagram of a renewable energy water electrolysis hydrogen production system based on the hybrid energy storage of a lithium ion battery and a superconducting energy storage magnet when an energy type energy storage device and a power type energy storage device are respectively a lithium ion battery and a superconducting energy storage;
FIG. 4 is a diagram of a hybrid energy storage system based on the hybrid energy storage of lithium ion batteries and superconducting energy storage magnets and the hydrogen production recycling of water electrolysis from renewable energy sources, when the energy storage device and the power storage device are respectively lithium ion batteries and superconducting energy storage, and the comprehensive utilization of superconducting energy storage and hydrogen energy is considered;
fig. 5 is a control block diagram of the hybrid energy storage system of the present invention.
In the figure: the system comprises a photovoltaic power generation device 1, a DC-DC Boost converter 2, an electrolytic bath 3, an energy type energy storage device 4, a first DC-DC converter 5, a power type energy storage device 6, a second DC-DC converter 7, a DC-AC converter 8, a power grid 9, a Dewar 10, a liquid hydrogen production device 11, a liquid hydrogen storage tank 12, a gas hydrogen storage tank 13, a gas pipeline 14, a liquid pipeline 15, a first comparator 16, a first PI controller 17, a low-pass filter 18, a second comparator 19, a second PI controller 20, a second PI controller output 21, a third comparator 22, a fourth comparator 23, a third PI controller 24 and a third PI controller output 25.
Detailed Description
Example 1:
the preferable scheme is as shown in figures 1 to 5, a large-scale photovoltaic electrolyzed water hydrogen production system and a method using a hybrid energy storage device comprise a photovoltaic power generation device 1, wherein the output end of the photovoltaic power generation device 1 is electrically connected with a DC-DC Boost converter 2, the energy flow between the photovoltaic power generation device 1 and the DC-DC Boost converter 2 is realized by MPPT control algorithm, the output end of the DC-DC Boost converter 2 is electrically connected with an electrolytic bath 3, two energy storage devices connected in parallel are connected on a direct current bus between the DC-DC Boost converter 2 and the electrolytic bath 3, the energy storage device comprises an energy type energy storage device 4 and a power type energy storage device 6, wherein the energy type energy storage device 4 is connected with the direct current bus through a first DC-DC converter 5, and the power type energy storage device 6 is connected with the direct current bus through a second DC-DC converter 7; the first DC-DC converter 5 is a bidirectional DC-DC converter, the energy storage device 4 is an electrochemical energy storage device, and the power storage device 6 is a super capacitor or a superconducting energy storage device.
The number of the electrolytic cells 3 is 1-n, the electrolytic cells 3 are connected in parallel, the number of the electrolytic cells 3 in the embodiment is four, S8, S9 and S10 are switches between the electrolytic cells respectively, the on and off of S8, S9 and S10 and the fluctuation of the photovoltaic power generation device 1 can cause the fluctuation and instability of the hydrogen production system, in order to solve the problem of the fluctuation and instability of the hydrogen production system, two energy storage devices which are connected in parallel are connected on a direct current bus between the DC-DC Boost converter 2 and the electrolytic cells 3, and the energy storage devices are respectively an energy type energy storage device 4 and a power type energy storage device 6. The energy storage device 4 and the power storage device 6 can improve the stability of the system, and meanwhile, the two energy storage devices respectively bear the low-frequency part and the high-frequency part of power fluctuation, so that the output of the energy storage device 4 can be smoothed, and the service life of the energy storage device is prolonged. The energy flow between the two energy storage devices and the direct current bus is realized by the first DC-DC converter 5 and the second DC-DC converter 7. The energy-type energy storage device 4 is mainly various electrochemical energy storage devices, the first DC-DC converter 5 between the energy-type energy storage device and the DC bus is a bidirectional DC-DC converter, and the bidirectional flow of energy between the DC bus and the electrochemical energy storage device can be realized by controlling the on and off of the power electronic switch S4 and the power electronic switch S5. The power storage means 6 may be a super capacitor or a superconducting storage means. When the power type energy storage device 6 is a super capacitor, the second DC-DC converter 7 between the power type energy storage device and the DC bus is also a bidirectional DC-DC converter, and energy bidirectional flow between the DC bus and the super capacitor is realized by controlling on and off of the power electronic switch S6 and the power electronic switch S7. When the power type energy storage device 6 is a superconducting energy storage device, the second DC-DC converter 7 between the power type energy storage device and the direct current bus is a DC-DC chopper, and energy can flow between the direct current bus and the superconducting energy storage device in two directions by controlling the on and off of the power electronic switch S6 and the power electronic switch S7.
Further, the direct current bus is connected with a power grid 9 through a DC-AC converter 8, a switch S1 is arranged between the direct current bus and the DC-AC converter 8, and the power grid 9 is used for supplying power to the electrolytic cell 3 when the photovoltaic power generation device 1 and the energy storage device are in failure or insufficient in power.
Further, hydrogen generated by the electrolytic cell 3 is stored by a gas hydrogen storage tank 13, the hydrogen in the gas hydrogen storage tank 13 is converted into liquid hydrogen by a liquid hydrogen making device 11 and is stored by a liquid hydrogen storage tank 12, the liquid hydrogen storage tank 12 is connected with a Dewar 10 by a liquid conveying pipeline 15, and the Dewar 10 is connected with the gas hydrogen storage tank 13 by a gas conveying pipeline 14; the dewar 10, the gas pipeline 14, the liquid hydrogen producing device 11, the liquid hydrogen storage tank 12 and the liquid pipeline 15 constitute a cooling system for refrigerating the magnet of the superconducting energy storage device. Thereby realizing the cyclic utilization of the superconducting energy storage and the hydrogen energy.
Example 2:
preferably, the operation method of the large-scale photovoltaic water electrolysis hydrogen production system utilizing the hybrid energy storage device is as follows:
parameter definition: the power of the photovoltaic power generation device 1 is P1, the energy storage device 4 and the energy storage device 6 form a hybrid energy storage device, the power of the hybrid energy storage device is P2= P3+ P4, wherein P3 is the power of the energy storage device 4, P4 is the power of the energy storage device 6, P5 is the power of the hydrogen production device by water electrolysis, and P6 is the power of the power grid 9;
the operation method comprises the following conditions:
case 1: the operation mode comprises the following modes in daytime but not in cloudy days:
1) when P1 is more than P5, the switch S1 between the power grid 9 and the direct current bus is in an off state, and the photovoltaic power generation device 1 supplies power to the hybrid energy storage device and the electrolytic cell 3 at the same time; at this time, the energy storage device 4 and the power storage device 6 are in a charging state until the charging state reaches a set target SOC threshold value; the energy type energy storage device 4 bears the low-frequency part of the power fluctuation, and the power type energy storage device 6 bears the high-frequency part of the power fluctuation;
2) when P1 is less than P5 and P1+ P2 is more than P5, the switch S1 between the power grid 6 and the direct current bus is still in an off state, and the photovoltaic power generation device 1 and the hybrid energy storage device simultaneously supply power to the electrolytic cell 3; at this time, the energy storage device 4 and the power storage device 6 are in a discharge state, the energy storage device 4 bears the low-frequency part of the power fluctuation, and the power storage device 6 bears the high-frequency part of the power fluctuation;
3) when P1 is less than P5 and P1+ P2 is less than P5, the switch S1 between the power grid 9 and the direct-current bus is in a closed state, the power grid 9 and the photovoltaic power generation device 1 simultaneously supply power to the hybrid energy storage device and the electrolytic cell 3 until the hybrid energy storage device is charged to the target SOC threshold value; at this time, the energy storage device 4 and the power storage device 6 are in a charging state; the energy type energy storage device 4 bears the low-frequency part of the power fluctuation, and the power type energy storage device 6 bears the high-frequency part of the power fluctuation;
case 2: at night or on cloudy days, the operation mode comprises the following modes:
1) when P2 is more than P5, the switch S1 between the power grid 9 and the direct-current bus is in an off state, the hybrid energy storage device supplies power to the electrolytic cell, the energy type energy storage device 4 bears the low-frequency part of power fluctuation, and the power type energy storage device 6 bears the high-frequency part of the power fluctuation;
2) when P2 is less than P5, the switch S1 between the power grid 9 and the direct-current bus is in a closed state, and the power grid 9 supplies power to the electrolytic cell 3 and the hybrid energy storage device until the battery is charged to the target SOC threshold value; the energy storage means 4 undertake the low frequency part of the power fluctuation and the power storage means 6 undertake the low frequency part of the power fluctuation.
As a supplementary technical solution, in the above operation mode, when the power type energy storage device 6 is a superconducting energy storage device, the hydrogen gas generated by the electrolytic cell 3 is directly stored in the gas hydrogen storage tank 13, and the gas hydrogen in the gas hydrogen storage tank 13 is converted into liquid hydrogen by the liquid hydrogen making device 11 and stored in the liquid hydrogen storage tank 12, and the conversion of the gas hydrogen and the liquid hydrogen in the dewar 10 is realized by the gas transmission pipeline 14 and the liquid transmission pipeline 15, so as to be used for refrigerating the superconducting energy storage magnet, thereby realizing the recycling of the superconducting energy storage and the hydrogen energy; program controllable switch valves are arranged on the gas pipeline 14 and the liquid pipeline 15 and are used for controlling the intellectualization of liquid hydrogen input and gas hydrogen output; a liquid hydrogen displacement measurement sensing device, a gas hydrogen concentration measurement sensing device and a Dewar internal pressure measurement sensing device are arranged in the Dewar 10; signals measured by the liquid hydrogen displacement measurement sensing device, the gas hydrogen concentration measurement sensing device and the Dewar internal pressure measurement sensing device are collected in real time by adopting a central controller, and the opening and closing of the program controllable switch valves on the gas pipeline 14 and the liquid pipeline 15 are controlled by comparing the measurement signals with the reference signals, so that the intelligent cyclic utilization of hydrogen and liquid hydrogen of the superconducting energy storage system is realized.
The control principle of the invention is as follows:
1. control method of photovoltaic power generation apparatus 1:
photovoltaic cells are a type of power generation device based on the photovoltaic effect, typically the photovoltaic effect. Depending on the characteristics of the photovoltaic cell, it has different V-I and V-P curves at different temperatures and different lighting conditions, for which there is a maximum power point. Therefore, in order to maximize the efficiency of the photovoltaic power generation device, the output voltage Vpv of the photovoltaic power generation device should be operated at the maximum power point through a control algorithm, which is a maximum power tracking MPPT algorithm. Vpv is the input of the DC-DC Boost converter 2 between the photovoltaic power plant 1 and the electrolyzer 3, Vd is the output of the DC-DC Boost converter 2 between the photovoltaic power plant 1 and the electrolyzer 3. Vd = D × Vpv according to the operating principle of the DC-DC Boost converter 2, where D is a conversion factor between Vd and Vpv. Under the condition of determining the direct current bus Vd, the bus voltage Vd can be controlled to be stabilized at a set value by combining an MPPT algorithm. Common MPPT algorithms include a constant voltage method, a conductance increment method, a climbing method and a control method combining various intelligent algorithms, and the control algorithm can be selected reasonably according to control requirements.
And a control mode of the hybrid energy storage device is as follows:
the hybrid energy storage device is composed of an energy type energy storage device 4 and a power type energy storage device 6, and according to the working characteristics of different energy storage devices, if the response of the energy type energy storage device 4 during power fluctuation is not smooth enough, the service life of the energy type energy storage device 4 is affected. Therefore, the hybrid energy storage device is applied to reasonably distribute high-frequency and low-frequency fluctuations of power between the power type energy storage device 6 and the energy type energy storage device 4, so that when the power fluctuates, the response of the energy type energy storage device 4 becomes smooth, and the service life of the energy type energy storage device 4 is further prolonged. Because the power fluctuation can be reflected on the voltage, the control of the hybrid energy storage device is also based on the stability of the bus voltage, and the energy type energy storage device 4 bears the low-frequency part of the power fluctuation and the power type energy storage device 6 bears the high-frequency part of the power fluctuation by adopting a frequency division control mode.
The energy storage device 4 is controlled in the following manner: the measured direct current bus voltage Vd and the direct current bus reference voltage Vd _ ref are compared through a first comparator 16 and input into a first PI controller 17 to obtain a reference current Iref; the first PI controller 17 performs frequency division processing on the reference current Iref to realize frequency division control of the energy storage device 4 and the power storage device 6; the reference current Iref passes through the low-pass filter 18 to output the Ib _ ref which is a low-frequency component of the reference current Iref, the Ib _ ref is compared with the measured current Ib of the energy storage device 4 through the second comparator 19 and is input into the second PI controller 20, and the second PI controller 20 controls the on and off of the power electronic switch S4 and the power electronic switch S5 of the bidirectional first DC-DC converter 5 between the energy storage device 4 and the DC bus;
the control mode of the power type energy storage device 6 is as follows: the reference current Iref subtracts the low frequency component of Ib _ ref from the third comparator 22 to obtain the high frequency component Ic _ ref of the reference current Iref, and the high frequency component Ic _ ref and Ic _ ref are compared with the measured current Ic of the power storage device by the fourth comparator 23 and input into the third PI controller 24, and the third PI controller output 25 of the third PI controller 24 controls the on and off of the power electronic switch S6 and the power electronic switch S7 of the second DC-DC converter 7 between the power storage device 6 and the DC bus.
3. And a power grid control mode:
the on and off of a switch S1 between the power grid 9 and the photovoltaic water electrolysis hydrogen production system are related to the power P1 of the photovoltaic power generation device 1, the power P2 of the hybrid energy storage device and the power P5 of the electrolytic cell 3 in the system. The power of each component in the system is monitored in real time, and the central controller controls the access and the cut-off of the power grid:
based on the principle, the hybrid energy storage device is organically combined with the photovoltaic water electrolysis hydrogen production system according to the characteristics of the energy type and power type energy storage devices. The output end of the photovoltaic power generation device is connected with the DC-DC Boost converter, the energy flow between the photovoltaic power generation device and the DC-DC Boost converter realizes the connection of the output end of the DC-DC Boost converter and the electrolytic cell through an MPPT control algorithm, and the problem of system instability caused by the volatility and the randomness of a photovoltaic power generation system is solved. Energy flow between the two energy storage devices and the direct current bus is realized through the DC-DC converter. The energy type energy storage devices are mainly various electrochemical energy storage devices, and the DC-DC converter between the energy type energy storage devices and the direct current bus is a bidirectional DC-DC converter, so that bidirectional flow of energy between the direct current bus and the electrochemical energy storage devices can be realized. The power storage device may be a super capacitor or a superconducting energy storage device. When the power type energy storage device is a super capacitor, the DC-DC converter between the power type energy storage device and the direct current bus is also a bidirectional DC-DC converter, and bidirectional energy flow between the direct current bus and the super capacitor is realized. When the power type energy storage device is a superconducting energy storage device, the DC-DC converter between the power type energy storage device and the direct current bus is a DC-DC chopper, and energy bidirectional flow between the direct current bus and the superconducting energy storage device can be realized. In addition, a hydrogen liquefying device can be added at the tail end of the water electrolysis hydrogen production system, and the produced liquid hydrogen is used for refrigerating the superconducting energy storage magnet, so that the recycling of the superconducting energy storage and the hydrogen energy is realized. The direct current bus at the front end of the electrolytic cell is connected with a power grid through a DC-AC converter, and when the photovoltaic power generation device and the energy storage device are in failure and the power of the photovoltaic power generation device and the energy storage device is insufficient to supply power to the electrolytic cell, a switch between the power grid and the direct current bus is closed, so that the power supply of the power grid to the electrolytic cell device is realized.
The above-described embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention is defined by the claims, and equivalents including technical features described in the claims. I.e., equivalent alterations and modifications within the scope hereof, are also intended to be within the scope of the invention.
Claims (8)
1. A large-scale photovoltaic electrolyzed water hydrogen production system utilizing a hybrid energy storage device comprises a photovoltaic power generation device (1) and is characterized in that: the output end of a photovoltaic power generation device (1) is electrically connected with a DC-DC Boost converter (2), the output end of the DC-DC Boost converter (2) is electrically connected with an electrolytic bath (3), two energy storage devices which are connected in parallel are connected on a direct current bus between the DC-DC Boost converter (2) and the electrolytic bath (3), each energy storage device comprises an energy type energy storage device (4) and a power type energy storage device (6), the energy type energy storage devices (4) are connected with the direct current bus through a first DC-DC converter (5), and the power type energy storage devices (6) are connected with the direct current bus through a second DC-DC converter (7); the first DC-DC converter (5) is a bidirectional DC-DC converter, the energy type energy storage device (4) is an electrochemical energy storage device, and the power type energy storage device (6) is a super capacitor or a superconducting energy storage device.
2. The large-scale photovoltaic water electrolysis hydrogen production system utilizing a hybrid energy storage device according to claim 1, characterized in that: the first DC-DC converter (5) and the direct current bus are controlled to be switched on and off through a power electronic switch S4 and a power electronic switch S5, and the energy bidirectional flow between the direct current bus and the energy storage device (4) is achieved.
3. The large-scale photovoltaic water electrolysis hydrogen production system utilizing a hybrid energy storage device according to claim 2, characterized in that: when the power type energy storage device (6) is a super capacitor, the second DC-DC converter (7) is a bidirectional DC-DC converter, and the connection and disconnection between the second DC-DC converter (7) and the direct current bus are controlled through a power electronic switch S6 and a power electronic switch S7, so that the bidirectional flow of energy between the direct current bus and the super capacitor is realized;
when the power type energy storage device (6) is a superconducting energy storage device, the second DC-DC converter (7) is a DC-DC chopper, and the connection and disconnection between the DC-DC chopper and the direct current bus are controlled through a power electronic switch S6 and a power electronic switch S7, so that the energy bidirectional flow between the direct current bus and the superconducting energy storage device is realized.
4. The large-scale photovoltaic water electrolysis hydrogen production system utilizing a hybrid energy storage device according to claim 3, characterized in that: the direct current bus is connected with a power grid (9) through a DC-AC converter (8), a switch S1 is arranged between the direct current bus and the DC-AC converter (8), and the power grid (9) is used for supplying power to the electrolytic cell (3) by the power grid when the photovoltaic power generation device (1) and the energy storage device are in failure or insufficient power.
5. The large-scale photovoltaic water electrolysis hydrogen production system using hybrid energy storage device according to claim 4, characterized in that: hydrogen generated by the electrolytic cell (3) is stored by a gas hydrogen storage tank (13), the hydrogen in the gas hydrogen storage tank (13) is converted into liquid hydrogen by a liquid hydrogen preparation device (11) and is stored by a liquid hydrogen storage tank (12), the liquid hydrogen storage tank (12) is connected with a Dewar (10) by a liquid conveying pipeline (15), and the Dewar (10) is connected with the gas hydrogen storage tank (13) by a gas conveying pipeline (14); the Dewar (10), the gas transmission pipeline (14), the liquid hydrogen preparation device (11), the liquid hydrogen storage tank (12) and the liquid transmission pipeline (15) form a cooling system, and the cooling system is used for refrigerating a magnet of the superconducting energy storage device.
6. The method for operating a large-scale photovoltaic water electrolysis hydrogen production system utilizing a hybrid energy storage device according to any one of claims 1 to 5, characterized in that:
parameter definition: the power of the photovoltaic power generation device (1) is P1, the energy type energy storage device (4) and the power type energy storage device (6) form a hybrid energy storage device, the power of the hybrid energy storage device is P2= P3+ P4, wherein P3 is the power of the energy type energy storage device (4), P4 is the power of the power type energy storage device (6), P5 is the power of the electrolyzed water hydrogen production device, and P6 is the power of a power grid (9);
the operation method comprises the following conditions:
case 1: the operation mode comprises the following modes in daytime but not in cloudy days:
1) when P1 is larger than P5, the switch S1 between the power grid (9) and the direct current bus is in an off state, and the photovoltaic power generation device (1) supplies power to the hybrid energy storage device and the electrolytic cell (3) at the same time; at the moment, the energy type energy storage device (4) and the power type energy storage device (6) are in a charging state until the charging state reaches a set target SOC threshold value; the energy type energy storage device (4) bears the low-frequency part of power fluctuation, and the power type energy storage device (6) bears the high-frequency part of the power fluctuation;
2) when P1 is less than P5 and P1+ P2 is more than P5, the switch S1 between the power grid 6 and the direct current bus is still in an off state, and the photovoltaic power generation device (1) and the hybrid energy storage device supply power to the electrolytic cell (3) simultaneously; at the moment, the energy type energy storage device (4) and the power type energy storage device (6) are in a discharge state, the energy type energy storage device (4) bears the low-frequency part of power fluctuation, and the power type energy storage device (6) bears the high-frequency part of the power fluctuation;
3) when P1 is less than P5 and P1+ P2 is less than P5, a switch S1 between the power grid (9) and the direct current bus is in a closed state, the power grid (9) and the photovoltaic power generation device (1) simultaneously supply power to the hybrid energy storage device and the electrolytic cell (3) until the hybrid energy storage device is charged to a target SOC threshold value; at the moment, the energy type energy storage device (4) and the power type energy storage device (6) are in a charging state; the energy type energy storage device (4) bears the low-frequency part of power fluctuation, and the power type energy storage device (6) bears the high-frequency part of the power fluctuation;
case 2: at night or on cloudy days, the operation mode comprises the following modes:
1) when P2 is more than P5, the switch S1 between the power grid (9) and the direct current bus is in an off state, the hybrid energy storage device supplies power to the electrolytic cell, the energy type energy storage device (4) bears the low-frequency part of power fluctuation, and the power type energy storage device (6) bears the high-frequency part of the power fluctuation;
2) when P2 is less than P5, the switch S1 between the power grid (9) and the direct-current bus is in a closed state, and the power grid (9) supplies power to the electrolytic cell (3) and the hybrid energy storage device until the battery is charged to the target SOC threshold value; the energy storage device (4) bears the low-frequency part of the power fluctuation, and the power storage device (6) bears the low-frequency part of the power fluctuation.
7. The method of operating a large-scale photovoltaic water electrolysis hydrogen production system using a hybrid energy storage device according to claim 6, wherein: when the power type energy storage device (6) is used for superconducting energy storage, hydrogen generated by the electrolytic tank (3) is directly stored in the gas hydrogen storage tank (13), the gas hydrogen in the gas hydrogen storage tank (13) is converted into liquid hydrogen through the liquid hydrogen preparation device (11) and is stored in the liquid hydrogen storage tank (12), the conversion of the gas hydrogen and the liquid hydrogen in the Dewar (10) is realized through the gas pipeline (14) and the liquid pipeline (15), and the gas hydrogen and the liquid hydrogen are used for refrigerating a superconducting energy storage magnet, so that the cyclic utilization of the superconducting energy storage and the hydrogen energy is realized; program controllable switch valves are arranged on the gas transmission pipeline (14) and the liquid transmission pipeline (15) and are used for controlling the intellectualization of liquid hydrogen input and gas hydrogen output; a liquid hydrogen displacement measurement sensing device, a gas hydrogen concentration measurement sensing device and a Dewar internal pressure measurement sensing device are arranged in the Dewar (10); signals measured by the liquid hydrogen displacement measurement sensing device, the gas hydrogen concentration measurement sensing device and the Dewar internal pressure measurement sensing device are collected in real time by adopting a central controller, and the opening and closing of program controllable switch valves on the gas pipeline (14) and the liquid pipeline (15) are controlled by comparing the measurement signals with reference signals, so that the hydrogen and liquid hydrogen of the superconducting energy storage system are intelligently recycled.
8. The method of operating a large-scale photovoltaic water electrolysis hydrogen production system using a hybrid energy storage device according to claim 6, wherein: the energy type energy storage device (4) is controlled in the following way: the measured direct current bus voltage Vd and the direct current bus reference voltage Vd _ ref are compared through a first comparator (16) and input into a first PI controller (17) to obtain reference current Iref; the first PI controller (17) carries out frequency division processing on the reference current Iref to realize frequency division control of the energy type energy storage device (4) and the power type energy storage device (6); ib _ ref output by the reference current Iref through the low-pass filter (18) is a low-frequency component of the reference current Iref, the Ib _ ref is compared with the measured current Ib of the energy storage device (4) through the second comparator (19) and is input into the second PI controller (20), and the second PI controller (20) controls the conduction and the disconnection of a power electronic switch S4 and a power electronic switch S5 of the bidirectional first DC-DC converter (5) between the energy storage device (4) and the direct-current bus;
the power type energy storage device (6) is controlled in the following way: the reference current Iref subtracts the low-frequency component of Ib _ ref through a third comparator (22) to obtain a high-frequency component Ic _ ref of the reference current Iref, the high-frequency component Ic _ ref is compared with the measured current Ic of the power type energy storage device through a fourth comparator (23) and is input into a third PI controller (24), and the third PI controller output (25) of the third PI controller (24) controls the on and off of a power electronic switch S6 and a power electronic switch S7 of a second DC-DC converter (7) between the power type energy storage device (6) and a direct current bus.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114752950A (en) * | 2022-05-16 | 2022-07-15 | 中国标准化研究院 | Wave type power input hydrogen production method and device by electrolyzing water |
| CN115011969A (en) * | 2022-05-31 | 2022-09-06 | 同济大学 | Hybrid hydrogen production system of coupled super capacitor and control method thereof |
| CN115094433A (en) * | 2022-05-31 | 2022-09-23 | 同济大学 | Hybrid hydrogen production system for coupling electrochemical power supply and super capacitor and control method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114752950A (en) * | 2022-05-16 | 2022-07-15 | 中国标准化研究院 | Wave type power input hydrogen production method and device by electrolyzing water |
| CN115011969A (en) * | 2022-05-31 | 2022-09-06 | 同济大学 | Hybrid hydrogen production system of coupled super capacitor and control method thereof |
| CN115094433A (en) * | 2022-05-31 | 2022-09-23 | 同济大学 | Hybrid hydrogen production system for coupling electrochemical power supply and super capacitor and control method |
| WO2023231274A1 (en) * | 2022-05-31 | 2023-12-07 | 同济大学 | Hybrid hydrogen production system coupled with supercapacitor, and control method therefor |
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