Power distribution control method for microgrid system integrating electricity, hydrogen and ammonia, and device

Abstract

The present application discloses a power distribution control method for a microgrid system integrating electricity, hydrogen and ammonia, and a device. The microgrid system comprises a direct current bus, an energy router, an ammonia cracking hydrogen production system, a hydrogen storage system, and a photovoltaic power generation system, a water electrolysis hydrogen production system, a hydrogen fuel cell system, an electrochemical energy storage system and a direct current load which are connected to the direct current bus by means of the energy router, wherein the direct current bus is connected to an external alternating current bus by means of the energy router, and the ammonia cracking hydrogen production system and the hydrogen storage system are both connected to the external alternating current bus. The method comprises: acquiring an output power of a photovoltaic power generation system and a power of a direct current load, and determining a charging and discharging power of a hybrid energy storage system composed of a hydrogen storage system and an electrochemical energy storage system; and acquiring an SOC value of the electrochemical energy storage system and an SOH value of the hydrogen storage system, and on the basis of the SOC value and the SOH value in combination with the charging and discharging power of the hybrid energy storage system, determining a power distribution control strategy so as to adjust an operating state of a microgrid system. The present application ensures stable and safe operation of the microgrid system.

Description

Power distribution control method and device for micro-grid system integrating electricity, hydrogen and ammonia TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-grid, in particular to a power distribution control method and device for a micro-grid system integrating electricity, hydrogen and ammonia. BACKGROUND

[0002] The micro-grid system refers to a small-scale power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, loads, monitoring and protection devices, etc., and is an autonomous system capable of self-regulation, protection and management, which can operate in parallel with the external power grid or in isolation. In consideration of the limited capacity of the energy storage device in the micro-grid system, how to effectively dynamically coordinate and control the operating state of the related devices in the micro-grid system to enable the micro-grid system to operate stably and safely is a technical problem to be solved.

[0003] SUMMARY

[0004] The present application provides a power distribution control method and device for a micro-grid system integrating electricity, hydrogen and ammonia, to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0005] In a first aspect, a power distribution control method for a micro-grid system integrating electricity, hydrogen and ammonia is provided. The micro-grid system includes a DC bus, an energy router, an ammonia cracking hydrogen production system, a hydrogen storage system, a photovoltaic power generation system, a water electrolysis hydrogen production system, a hydrogen fuel cell system, an electrochemical energy storage system and a DC load connected to the DC bus through the energy router. The DC bus is connected to an external AC bus through the energy router. The ammonia cracking hydrogen production system and the hydrogen storage system are connected to the external AC bus. The ammonia cracking hydrogen production system and the water electrolysis hydrogen production system are connected to the hydrogen storage system. The hydrogen storage system is connected to the hydrogen fuel cell system. The hydrogen storage system and the electrochemical energy storage system constitute a hybrid energy storage system. The method comprises:

[0006] Obtaining the output power of the photovoltaic power generation system and the power of the DC load, and then determining the charge and discharge power of the hybrid energy storage system;

[0007] Obtaining the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system, and then determining the power distribution control strategy for the micro-grid system in combination with the charge and discharge power of the hybrid energy storage system;

[0008] Adjusting the operating state of the micro-grid system according to the power distribution control strategy.

[0009] Further, the determining the power distribution control strategy for the micro-grid system comprises:

[0010] obtaining a normal SOC range of the electrochemical energy storage system and denoted as (SOC min , SOC max ), and determining a first relationship between the SOC value of the electrochemical energy storage system and the normal SOC range;

[0011] obtaining a normal SOH range of the hydrogen storage system and denoted as (SOH min , SOH max ), and determining a second relationship between the SOH value of the hydrogen storage system and the normal SOH range;

[0012] when the charge-discharge power of the hybrid energy storage system is greater than zero, combining the first relationship and the second relationship to determine a first power distribution control strategy, which comprises controlling the electrochemical energy storage system to charge and / or controlling the water electrolysis hydrogen production system to produce hydrogen;

[0013] when the charge-discharge power of the hybrid energy storage system is less than zero, combining the first relationship and the second relationship to determine a second power distribution control strategy, which comprises controlling the electrochemical energy storage system to discharge and / or controlling the hydrogen fuel cell system to generate electricity.

[0014] Further, the first power distribution control strategy specifically comprises:

[0015] when SOC(t)≤SOC min and SOH(t)≤SOH min , or when SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max , and the charge-discharge power of the hybrid energy storage system is greater than or equal to the rated maximum output power of the electrochemical energy storage system, setting the rated maximum output power of the electrochemical energy storage system as a first power reference value, setting the difference between the charge-discharge power of the hybrid energy storage system and the rated maximum output power of the electrochemical energy storage system as a second power reference value, controlling the electrochemical energy storage system to charge at the first power reference value, and controlling the water electrolysis hydrogen production system to produce hydrogen at the second power reference value;

[0016] when SOC(t)≤SOC min and SOH min <SOH(t)<SOH max , or when SOC(t)≤SOC min and SOH(t)≥SOH maxWhen SOC(t) < SOC min When SOC(t) < SOC max and SOH(t) ≥ SOH max The charging and discharging power of the hybrid energy storage system is set as a third power reference value, and the electrochemical energy storage system is controlled to charge at the third power reference value.

[0017] When SOC(t) < SOC min When SOC(t) < SOC max and SOH(t) ≤ SOH min When SOC(t) ≥ SOC max and SOH(t) ≤ SOH min When SOC(t) ≥ SOC max and SOH min <SOH(t) < SOH max The water electrolysis hydrogen production system is controlled to produce hydrogen at the third power reference value.

[0018] When SOC(t) < SOC min When SOC(t) < SOC max , SOH min <SOH(t) < SOH max and the charging and discharging power of the hybrid energy storage system is less than the rated maximum output power of the electrochemical energy storage system, the electrochemical energy storage system is controlled to charge at the third power reference value.

[0019] When SOC(t) ≥ SOC max and SOH(t) ≥ SOH max The product of the charging and discharging power of the hybrid energy storage system and a given accommodation coordination coefficient is set as a fourth power reference value, and the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value.

[0020] Further, the microgrid system further comprises a hydrogen load connected with the hydrogen storage system.

[0021] When SOC(t) ≤ SOC min and SOH(t) ≥ SOH max When SOC(t) < SOC min When SOC(t) < SOC max and SOH(t) ≥ SOH max The electrochemical energy storage system is controlled to charge at the third power reference value, and the hydrogen load is started to operate.

[0022] Further, when SOC(t) ≥ SOC max and SOH(t) ≥ SOH maxAt this time, while the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value, the micro-grid system is operated in parallel to feed back alternating current to the external alternating current bus, the difference between the charge and discharge power of the hybrid energy storage system and the fourth power reference value is set as a fifth power reference value, the electrochemical energy storage system is controlled to discharge at the fifth power reference value, and the hydrogen load is started.

[0023] Further, the second power distribution control strategy specifically includes:

[0024] When SOC(t)≤SOC min and SOH(t)≤SOH min , the product of the charge and discharge power of the hybrid energy storage system and a given compensation coordination coefficient is set as a sixth power reference value, and the hydrogen fuel cell system is controlled to generate power at the sixth power reference value.

[0025] When SOC(t)≤SOC min and SOH min <SOH(t)<SOH max , or when SOC(t)≤SOC min and SOH(t)≥SOH max , or when SOC min <SOC(t)<SOC max and SOH(t)≥SOH max , the hydrogen fuel cell system is controlled to generate power at the third power reference value.

[0026] When SOC min <SOC(t)<SOC max and SOH(t)≤SOH min , or when SOC(t)≥SOC max and SOH(t)≤SOH min , or when SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max , and the charge and discharge power of the hybrid energy storage system is less than the rated maximum output power of the electrochemical energy storage system, the electrochemical energy storage system is controlled to discharge at the third power reference value.

[0027] When SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH maxand the charge-discharge power of the hybrid energy storage system is greater than or equal to the rated maximum output power of the electrochemical energy storage system, or when SOC(t)≥SOC max and SOH(t)≥SOH max , the electrochemical energy storage system is controlled to discharge at the first power reference value, and the hydrogen fuel cell system is controlled to generate electricity at the second power reference value.

[0028] When SOC(t)≥SOC max and SOH min <SOH(t)<SOH max , the electrochemical energy storage system is controlled to discharge at the first power reference value.

[0029] Further, when SOC(t)≤SOC min and SOH(t)≤SOH min , the micro-grid system is controlled to operate in parallel to make the DC bus obtain DC power, the difference between the charge-discharge power of the hybrid energy storage system and the sixth power reference value is set as a seventh power reference value, the electrochemical energy storage system is controlled to charge at the seventh power reference value, and the ammonia cracking hydrogen production system is controlled to produce hydrogen.

[0030] Further, when SOC min <SOC(t)<SOC max and SOH(t)≤SOH min , or when SOC(t)≥SOC max and SOH(t)≤SOH min , the electrochemical energy storage system is controlled to discharge at the third power reference value, and the ammonia cracking hydrogen production system is controlled to produce hydrogen.

[0031] Further, the method further comprises: when the charge-discharge power of the hybrid energy storage system is zero, keeping the operating state of the micro-grid system unchanged.

[0032] In a second aspect, a computer device is provided, comprising a memory and a processor, the memory stores a computer program, and the processor executes the computer program to realize the power distribution control method of the fusion electric hydrogen ammonia micro-grid system according to the first aspect.

[0033] The application has at least the following beneficial effects: by flexibly adjusting the operation state of the micro-grid system according to the first relationship between the SOC value of the electrochemical energy storage system and the normal SOC range and the second relationship between the SOH value of the hydrogen storage system and the normal SOH range when the charge and discharge power of the hybrid energy storage system is unbalanced, the voltage stability and power balance of the DC bus can be ensured, the output of the photovoltaic power generation system can be maximized, the dependence on the distribution network can be reduced, the self-balancing capability of the micro-grid system can be improved, and the service life of the electrochemical energy storage system and the hydrogen storage system can be effectively prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0035] FIG. 1 is a composition schematic diagram of a micro-grid system integrating electricity, hydrogen and ammonia according to an embodiment of the present application;

[0036] FIG. 2 is a flow schematic diagram of a power distribution control method of a micro-grid system integrating electricity, hydrogen and ammonia according to an embodiment of the present application;

[0037] FIG. 3 is a hardware structure schematic diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0039] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in an order different from that in the flowchart. The terms "first", "second", etc. in the specification and claims and the above-described drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

[0041] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0042] The flowcharts shown in the drawings are merely illustrative and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0043] Please refer to FIG. 1, which is a schematic diagram of a micro-grid system for integrated electric hydrogen and ammonia provided by an embodiment of the application. The micro-grid system specifically includes an energy router, a DC bus, a hydrogen storage system, an ammonia cracking hydrogen production system, a hydrogen load, and a water electrolysis hydrogen production system, a photovoltaic power generation system, an electrochemical energy storage system, a hydrogen fuel cell system, and a DC load connected via the energy router and the DC bus. The electrochemical energy storage system and the hydrogen storage system constitute a hybrid energy storage system. Basically, the DC bus is connected to an external AC bus via the energy router, the ammonia cracking hydrogen production system is connected to the external AC bus, and the hydrogen storage system is connected to the external AC bus. The ammonia cracking hydrogen production system is connected to the hydrogen storage system, the water electrolysis hydrogen production system is connected to the hydrogen storage system, the hydrogen storage system is connected to the hydrogen fuel cell system, and the hydrogen storage system is connected to the hydrogen load.

[0044] More specifically, the energy router comprises a first DC / DC converter, a second DC / DC converter, a third DC / DC converter, a fourth DC / DC converter, a bidirectional DC / DC converter and a bidirectional DC / AC converter, the photovoltaic power generation system is connected to the DC bus via the first DC / DC converter, the water electrolysis hydrogen production system is connected to the DC bus via the second DC / DC converter, the hydrogen fuel cell system is connected to the DC bus via the third DC / DC converter, the DC load is connected to the DC bus via the fourth DC / DC converter, the electrochemical energy storage system is connected to the DC bus via the bidirectional DC / DC converter, and the DC bus is connected to the external AC bus via the bidirectional DC / AC converter; the energy router can realize electrical isolation, voltage conversion and bidirectional flow of electric energy, provide a "plug and play" standardized interface for different levels and different forms of sources and loads, and can adjust the voltage and current of each converter in real time.

[0045] In practical applications, the photovoltaic power generation system converts the solar energy captured by itself into electric energy through the photovoltaic effect, and the electric energy is directly incorporated into the DC bus after being converted by the first DC / DC converter, thereby providing power for the water electrolysis hydrogen production system and the DC load, and being stored through the electrochemical energy storage system;

[0046] The DC bus provides electric energy for the water electrolysis hydrogen production system to realize consumption after the electric energy is converted in voltage level by the second DC / DC converter, and the hydrogen produced by the water electrolysis hydrogen production system during operation is stored through the hydrogen storage system, and the hydrogen produced by the ammonia cracking hydrogen production system during operation is also stored through the hydrogen storage system, and the hydrogen storage system and the ammonia cracking hydrogen production system are powered by the external AC bus;

[0047] The hydrogen fuel cell system can convert the hydrogen stored in the hydrogen storage system into electric energy, and the electric energy is incorporated into the DC bus after being converted in voltage level by the third DC / DC converter to realize compensation; in addition, the hydrogen stored in the hydrogen storage system can also be supplied to the hydrogen load to further solve the problem of limited capacity of the hydrogen storage system;

[0048] The electric energy provided by the DC bus is input to the electrochemical energy storage system for storage to realize consumption after being converted in voltage level by the bidirectional DC / DC converter; the electrochemical energy storage system incorporates the electric energy stored therein into the DC bus to realize compensation after the electric energy is converted in voltage level by the bidirectional DC / DC converter;

[0049] The bidirectional DC / AC converter can be understood as a grid-connected port for realizing AC / DC conversion and bidirectional power flow between the DC bus and the external AC bus.

[0050] It should be noted that the micro-grid system can be configured in an industrial park, a residential area, an island power consumption site, a backup site, or other places.

[0051] In the micro-grid system, the capacity of the electrochemical energy storage system and the hydrogen storage system is limited. When the electrochemical energy storage system or the hydrogen storage system needs to store energy or discharge, if the SOC (State of Charge) value of the electrochemical energy storage system and the SOH (State of Health) value of the hydrogen storage system are both in a high state or a low state, the system will be forced to abandon light or cut off load, which is easy to cause the micro-grid system to fluctuate or even the micro-source to exit operation. In order to ensure the stable and safe operation of the micro-grid system, the power distribution control of each related system contained in the micro-grid system needs to be controlled according to the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system.

[0052] On this basis, FIG. 2 is a power distribution control method of a micro-grid system integrating electricity, hydrogen, and ammonia provided by an embodiment of the present application, which specifically includes the following steps:

[0053] In step S110, the output power of the photovoltaic power generation system and the power of the DC load are obtained, and then the charge and discharge power of the hybrid energy storage system is determined.

[0054] The charge and discharge power of the hybrid energy storage system is the difference between the output power of the photovoltaic power generation system and the power of the DC load.

[0055] In step S120, the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system are obtained, and then the power distribution control strategy of the micro-grid system is determined in combination with the charge and discharge power of the hybrid energy storage system.

[0056] In step S130, the operation state of the micro-grid system is adjusted according to the power distribution control strategy.

[0057] In some embodiments of the present application, the SOH value of the hydrogen storage system and the SOC value of the electrochemical energy storage system mentioned in the above step S120 are preferentially explained as follows:

[0058] (1) The hydrogen storage tank is used as the energy storage unit of the hydrogen storage system, and the SOH value of the hydrogen storage system is determined by the ratio of the maximum internal pressure of the hydrogen storage system to the internal pressure of the hydrogen storage system, that is:

[0059] wherein SOH(t) is the SOH value of the hydrogen storage system at time t, P ST (t) is the internal pressure of the hydrogen storage system at time t, P ST max is the maximum internal pressure of the hydrogen storage system, m ST (t) is the hydrogen storage amount of the hydrogen storage system at time t, R is the gas constant, T ST (t) is the internal gas thermodynamic temperature of the hydrogen storage system at time t, V ST is the geometric volume of the hydrogen storage system, m ST (t-1) is the hydrogen storage amount of the hydrogen storage system at time t-1, v STin (t) is the hydrogen charging rate of the hydrogen storage system at time t, v STout (t) is the hydrogen discharging rate of the hydrogen storage system at time t.

[0060] (2) using a lithium battery as the energy storage unit of the electrochemical energy storage system, the mathematical model thereof is:

[0061] The SOC value of the electrochemical energy storage system is defined as the ratio of the remaining capacity of the lithium battery to the maximum capacity of the lithium battery, reflecting the actual availability of the lithium battery, which can be calculated using the following expression:

[0062] wherein U BAT (t) is the input voltage of the lithium battery, I BAT (t) is the input current of the lithium battery, U BAT (t) is the output voltage of the lithium battery, I BAT (t) is the output current of the lithium battery, E0 is the voltage constant of the lithium battery, K e is the polarization constant of the lithium battery, Q is the maximum capacity of the lithium battery, I t is the extractable electric energy of the lithium battery, I * is the low-frequency dynamic current of the lithium battery, A b is the exponential zone amplitude, B is the exponential zone time reverse proportion, R res is the polarization resistance of the lithium battery, R b is the internal resistance of the lithium battery, SOC(t) is the SOC value of the electrochemical energy storage system at time t, when SOC(t) = 0, it indicates that the lithium battery is completely discharged, and when SOC(t) = 1, it indicates that the lithium battery is fully charged.

[0063] In some embodiments of the present application, the implementation of step S120 includes but is not limited to the following:

[0064] Step S121, obtaining the SOC value of the electrochemical energy storage system and the normal SOC range, and determining the first relationship between the SOC value of the electrochemical energy storage system and the normal SOC range;

[0065] wherein the normal SOC range of the electrochemical energy storage system is denoted as (SOC min , SOC max ), and considering the working life and performance of the electrochemical energy storage system, the minimum SOC limit value is preferably set as SOC min = 0.25 and the maximum SOC limit value is preferably set as SOC max = 0.85, the first relationship is SOC(t)≤SOC min or SOC min < SOC(t) < SOC max or SOC(t)≥SOC max ;

[0066] Step S122, obtaining the SOH value of the hydrogen storage system and the normal SOH range, and determining the second relationship between the SOH value of the hydrogen storage system and the normal SOH range;

[0067] wherein the normal SOH range of the hydrogen storage system is denoted as (SOH min , SOH max ), and considering the working life and performance of the hydrogen storage system, the minimum SOH limit value is preferably set as SOH min = 0.2 and the maximum SOH limit value is preferably set as SOH max = 0.75, the second relationship is SOH(t)≤SOH min or SOH min < SOH(t) < SOH max or SOH(t)≥SOH max ;

[0068] Step S123, judging the charge and discharge power of the hybrid energy storage system, which specifically includes:

[0069] denoted as P BHF (t), when P BHF (t) > 0, step S124 is executed, when P BHF (t) < 0, step S125 is executed, and when P BHF (t) = 0, the operation state of the micro-grid system remains unchanged;

[0070] Step S124, determining a first power distribution control strategy according to the first relationship, the second relationship and the charge-discharge power of the hybrid energy storage system, which mainly includes controlling the water electrolysis hydrogen production system to produce hydrogen and / or controlling the electrochemical energy storage system to charge;

[0071] Step S125, determining a second power distribution control strategy according to the first relationship, the second relationship and the charge-discharge power of the hybrid energy storage system, which mainly includes controlling the hydrogen fuel cell system to generate electricity and / or controlling the electrochemical energy storage system to discharge.

[0072] Before explaining the first power distribution control strategy mentioned in the above step S124 and the second power distribution control strategy mentioned in the above step S125, the following related parameters are set:

[0073] The rated maximum output power of the electrochemical energy storage system is denoted as P BE max The rated maximum output power of the electrochemical energy storage system is denoted as P BE max The difference between the charge-discharge power P BHF (t) of the hybrid energy storage system and the rated maximum output power P BE max of the electrochemical energy storage system is defined as a first power reference value. BHF The product of the charge-discharge power P BHF (t) of the hybrid energy storage system and a pre-set accommodation coordination coefficient k 21 is defined as a fourth power reference value. BHF The difference between the charge-discharge power P BHF (t) of the hybrid energy storage system and the fourth power reference value is defined as a fifth power reference value. 22 The product of the charge-discharge power P BHF (t) of the hybrid energy storage system and a pre-set compensation coordination coefficient k 21 is defined as a sixth power reference value. 22 The difference between the charge-discharge power P

[0074] More specifically, the first power distribution control strategy mentioned in the above step S124 is explained as follows:

[0075] The first case: when SOC(t)≤SOC minand SOH(t)≤SOH min , control the electrochemical energy storage system to charge according to the first power reference value until the SOC value is k 11 (SOC max -SOC min ), k 11 is a SOC adjustment coefficient, the value range of k 11 (SOC max -SOC min ) is 0.4-0.6 (or the value range of k 11 is 0.8-1.2), at this time, set the power reference value of the electrochemical energy storage system during charging as P Bref =P BE max ; then control the water electrolysis hydrogen production system to produce hydrogen according to the second power reference value, that is, set the power reference value of the water electrolysis hydrogen production system during hydrogen production as P Href =P BHF (t)-P BE max , so as to restore the hydrogen storage amount in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually rises;

[0076] As an optional embodiment, after controlling the electrochemical energy storage system to charge according to the first power reference value, directly control the ammonia cracking hydrogen production system to produce hydrogen according to the rated maximum output power, restore the hydrogen storage amount in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually rises.

[0077] The second case: when SOC(t)≤SOC min and SOH min <SOH(t)<SOH max , control the electrochemical energy storage system to charge according to the third power reference value, that is, set the power reference value of the electrochemical energy storage system during charging as P Bref =P BHF (t), so as to realize consumption.

[0078] The third case: when SOC(t)≤SOC min and SOH(t)≥SOH max , or when SOC min <SOC(t)<SOC max and SOH(t)≥SOH max , control the electrochemical energy storage system to charge according to the third power reference value, that is, set the power reference value of the electrochemical energy storage system during charging as P Bref =P BHF(t) to achieve absorption; at the same time, control the operation of the hydrogen load so that the SOH value of the hydrogen storage system gradually decreases to the normal SOH range;

[0079] The fourth scenario: when SOC min <SOC(t)<SOC max And SOH(t)≤SOH min When, or when SOC(t)≥SOC max And SOH(t)≤SOH min When, or when SOC(t)≥SOC max And SOH min <SOH(t)<SOH max At that time, the water electrolysis hydrogen production system is controlled to produce hydrogen according to the third power reference value, that is, the power reference value of the water electrolysis hydrogen production system during hydrogen production is set to P. Href =P BHF (t) to achieve consumption;

[0080] Fifth case: When SOC min <SOC(t)<SOC max And SOH min <SOH(t)<SOH max When, if P BHF (t) <P BE max Then, the electrochemical energy storage system is controlled to charge according to the third power reference value, that is, the power reference value of the electrochemical energy storage system during charging is set to P. Bref =P BHF (t) to achieve absorption; if P BHF (t)≥P BE max First, the electrochemical energy storage system is controlled to charge according to the first power reference value, that is, the power reference value of the electrochemical energy storage system during charging is set to P. Bref =P BE max Then, the water electrolysis hydrogen production system is controlled to produce hydrogen according to the second power reference value, and the power reference value of the water electrolysis hydrogen production system during hydrogen production is set to P. Href =P BHF (t)-P BE max In order to achieve the purpose of consumption.

[0081] The sixth case: when SOC(t) ≥ SOC max And SOH(t)≥SOH max At that time, the water electrolysis hydrogen production system is controlled to produce hydrogen according to the fourth power reference value, that is, the power reference value of the water electrolysis hydrogen production system during hydrogen production is set to P. Href =k 21 P BHF(t) to achieve consumption;

[0082] Meanwhile, the following two auxiliary control actions need to be made: ① control the micro-grid system to operate in grid-connected mode, feed back AC power to the external AC bus by starting the bidirectional DC / AC converter, and control the electrochemical energy storage system to discharge according to the fifth power reference value, that is, set the power reference value of the electrochemical energy storage system when discharging as P Bref = (1-k 21 )P BHF (t), so that the SOC value of the electrochemical energy storage system gradually decreases to the normal SOC range; ② control the hydrogen load to operate, restore the hydrogen storage in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually decreases to the normal SOH range.

[0083] More specifically, the second power distribution control strategy mentioned in the above step S125 will be described in the following six cases:

[0084] The first case: when SOC(t)≤SOC min and SOH(t)≤SOH min , control the hydrogen fuel cell system to generate electricity according to the sixth power reference value, that is, set the power reference value of the hydrogen fuel cell system when generating electricity as P Fref = k 22 P BHF (t);

[0085] Meanwhile, the following two auxiliary control actions need to be made: ① control the micro-grid system to operate in grid-connected mode, make the DC bus obtain DC power by starting the bidirectional DC / AC converter, and control the electrochemical energy storage system to charge according to the seventh power reference value, that is, set the power reference value of the electrochemical energy storage system when charging as P Bref = (1-k 22 )P BHF (t), so that the SOC value of the electrochemical energy storage system gradually increases to the normal SOC range; ② control the ammonia cracking hydrogen production system to produce hydrogen according to the rated maximum output power, to restore the hydrogen storage in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually increases to the normal SOH range.

[0086] The second case: when SOC(t)≤SOC min and SOH min <SOH(t)<SOH max , or when SOC(t)≤SOC min and SOH(t)≥SOH max , or when SOC minSOC(t) < SOC max and SOH(t) ≥ SOH max , the hydrogen fuel cell system is controlled to generate electricity according to the third power reference value, i.e., the power reference value of the hydrogen fuel cell system during electricity generation is set as P Fref = P BHF (t) to achieve compensation.

[0087] The third case: when SOC min SOC(t) < SOC max and SOH(t) ≤ SOH min , or when SOC(t) ≥ SOC max and SOH(t) ≤ SOH min , the electrochemical energy storage system is controlled to discharge according to the third power reference value, i.e., the power reference value of the electrochemical energy storage system during discharging is set as P Bref = P BHF (t) to achieve compensation; at the same time, the ammonia cracking hydrogen production system is controlled to produce hydrogen according to the rated maximum output power, so that the SOH value of the hydrogen storage system gradually rises to the normal SOH range.

[0088] The fourth case: when SOC min SOC(t) < SOC max and SOH min < SOH(t) < SOH max , if P BHF (t) < P BE max , the electrochemical energy storage system is controlled to discharge according to the third power reference value, i.e., the power reference value of the electrochemical energy storage system during discharging is set as P Bref = P BHF (t) to achieve compensation; if P BHF (t) ≥ P BE max , the electrochemical energy storage system is first controlled to discharge according to the first power reference value, i.e., the power reference value of the electrochemical energy storage system during discharging is set as P Bref = P BE max , and then the hydrogen fuel cell system is controlled to generate electricity according to the second power reference value, i.e., the power reference value of the hydrogen fuel cell system during electricity generation is set as P Fref = P BHF (t) - P BE max to achieve compensation.

[0089] The fifth case: when SOC(t) ≥ SOC max and SOH min < SOH(t) < SOH maxAt that time, the electrochemical energy storage system is controlled to discharge according to the first power reference value, that is, the power reference value of the electrochemical energy storage system during discharge is set to P. Bref =P BE max In order to achieve compensation.

[0090] The sixth case: when SOC(t) ≥ SOC max And SOH(t)≥SOH max At that time, the electrochemical energy storage system is controlled to discharge according to the first power reference value until the SOC value is k. 12 (SOC max -SOC min ), k 12 To compensate for the SOC adjustment coefficient, k is limited. 12 (SOC max -SOC min The value range of k is 0.3 to 0.4 (or k 12 The value range is 0.6 to 0.8), and then the hydrogen fuel cell system is controlled to generate electricity according to the second power reference value, that is, the power reference value of the hydrogen fuel cell system when generating electricity is set to P. Fref =P BHF (t)-P BE max This causes the SOH value of the hydrogen storage system to gradually decrease to the normal SOH range.

[0091] Furthermore, the specific operation and control methods of the electrochemical energy storage system, the water electrolysis hydrogen production system, and the hydrogen fuel cell system are described below:

[0092] (1) To control the electrochemical energy storage system according to the corresponding power reference value P Bref During charging or discharging, the measured voltage U of the DC bus is obtained. DC and reference voltage U DCref Obtain the measured terminal current I of the electrochemical energy storage system. B The measured voltage U is controlled by a pre-set first control strategy. DC and the reference voltage U DCref The reference voltage U of the electrochemical energy storage system was obtained through analysis. Bref The power reference value P Bref With the reference voltage U Bref The reference current I of the electrochemical energy storage system is obtained by performing phase division. Bref The reference current I is controlled by a pre-set second control strategy. Bref and the measured terminal current I B The duty cycle u required to control the operation of the electrochemical energy storage system is obtained through analysis. B, the duty cycle u B in response to change the output power of the electrochemical energy storage system;

[0093] (2) If the water electrolysis hydrogen production system is required to produce hydrogen according to a corresponding power reference value P Href , the measured terminal voltage U H and the measured terminal current I H of the water electrolysis hydrogen production system are obtained, the power reference value P Href is divided by the measured terminal voltage U H to obtain the reference current I Href of the water electrolysis hydrogen production system, the reference current I Href and the measured terminal current I H are analyzed by using a pre-set third control strategy to obtain the duty cycle u H required to control the operation of the water electrolysis hydrogen production system, and the second DC / DC converter responds to the duty cycle u H to change the output power of the water electrolysis hydrogen production system;

[0094] (3) If the hydrogen fuel cell system is required to generate electricity according to a corresponding power reference value P Fref , the measured terminal voltage U F and the measured terminal current I F of the hydrogen fuel cell system are obtained, the power reference value P Fref is divided by the measured terminal voltage U F to obtain the reference current I Fref of the hydrogen fuel cell system, the reference current I Fref and the measured terminal current I F are analyzed by using a pre-set fourth control strategy to obtain the duty cycle u F required to control the operation of the hydrogen fuel cell system, and the third DC / DC converter responds to the duty cycle u F to change the output power of the hydrogen fuel cell system;

[0095] The first control strategy, the second control strategy, the third control strategy and the fourth control strategy can be, but are not limited to, existing PID control strategy or fuzzy control strategy or neural network control strategy.

[0096] In the embodiments of the present application, by adjusting the operation state of the micro-grid system flexibly according to the first relationship between the SOC value of the electrochemical energy storage system and the normal SOC range and the second relationship between the SOH value of the hydrogen storage system and the normal SOH range when the charge and discharge power of the hybrid energy storage system is unbalanced, the voltage stability and power balance of the DC bus can be ensured, the output of the photovoltaic power generation system can be maximized, the dependence on the distribution network can be reduced, the self-balancing capability of the micro-grid system can be improved, and the service life of the electrochemical energy storage system and the hydrogen storage system can be effectively prolonged.

[0097] In addition, the present application also provides a computer readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the power distribution control method of the hybrid hydrogen-ammonia micro-grid system in the above embodiments. The computer readable storage medium includes, but is not limited to, any type of disk (including floppy disks, hard disks, optical disks, CD-ROMs, and magneto-optical disks), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic cards or optical cards. That is, the storage device includes any medium that stores or transmits information in a readable form by a device (such as a computer, a mobile phone, etc.), which can be a read-only memory, a magnetic disk or an optical disk, etc.

[0098] In addition, FIG. 3 is a schematic diagram of a hardware structure of a computer device according to an embodiment of the present application. The computer device includes a processor 220, a memory 230, an input unit 240, a display unit 250, and the like. Those skilled in the art can understand that the device structure shown in FIG. 3 does not constitute a limitation on all devices, and can include more or fewer components than shown, or combine certain components. The memory 230 can be used to store a computer program 210 and various functional modules. The processor 220 runs the computer program 210 stored in the memory 230, thereby performing various functional applications and data processing of the device. The memory can be an internal memory or an external memory, or include an internal memory and an external memory. The internal memory can include a read-only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, or a random access memory. The external memory can include a hard disk, a floppy disk, a USB memory, a magnetic tape, and the like. The memory 230 disclosed in the embodiments of the present application includes but is not limited to the above-mentioned types of memory. The memory 230 disclosed in the embodiments of the present application is only by way of example and not as a limitation.

[0099] The input unit 240 is used to receive the input of signals and receive the keyword input by the user. The input unit 240 can include a touch panel and other input devices. The touch panel can collect the touch operation of the user thereon or nearby (such as the operation of the user using a finger, a stylus, or any suitable object or accessory on or near the touch panel), and drive the corresponding connection device according to the pre-set program; the other input devices can include but are not limited to one or more of a physical keyboard, function keys (such as play control buttons, switch buttons, etc.), a trackball, a mouse, a joystick, and the like. The display unit 250 can be used to display the information input by the user or the information provided to the user and various menus of the terminal device. The display unit 250 can take the form of a liquid crystal display, an organic light-emitting diode, and the like. The processor 220 is the control center of the terminal device, which connects all parts of the device through various interfaces and lines, executes the software program and / or module stored in the memory 230, and calls the data stored in the memory 230, to perform various functions and process data.

[0100] As an embodiment, the computer device includes a processor 220, a memory 230, and a computer program 210, wherein the computer program 210 is stored in the memory 230 and configured to be executed by the processor 220, and the computer program 210 is configured to perform the power distribution control method of the micro-grid system for integrated electric hydrogen ammonia in the above-mentioned embodiments.

[0101] The terms "including", "containing", "having" and their conjugates, as used throughout the present application and the preceding description of the related drawings, are meant to encompass the presence of stated features, steps or elements, but not the exclusion of others thereof. The use of the indefinite article "a" or "an" preceding an element, installation, fabrication or step is not meant to restrict the number of those elements but to represent an example of at least one. The use of the definite article "the" preceding an element, installation, fabrication or step is not meant in a limiting sense, but to refer to that element, installation, fabrication or step in combination with at least one of the preceding or following occurrences of the same.

[0102] In the present application, it should be understood that "at least one" means one or more, "multiple" means two or more. "And / or" is used to describe the relationship between associated objects, which means that there can be three relationships, for example, "A and / or B" can mean: only A, only B, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0103] Although the description of the present application has been quite detailed and particularly described with respect to several described embodiments, it is not intended to be limited to any of these details or embodiments or any special embodiment, but should be considered to effectively cover the intended scope of the present application by reference to the appended claims, taking into account the prior art, providing a broad interpretation of these claims. In addition, the present application is described above in embodiments that the inventor can foresee, the purpose of which is to provide a useful description, and non-essential modifications to the present application that have not yet been foreseen can still represent equivalent modifications of the present application.

Claims

1. A power distribution control method of a microgrid system integrating power-to-hydrogen-to-ammonia, the microgrid system comprising a DC bus, an energy router, an ammonia cracking hydrogen production system, a hydrogen storage system, a photovoltaic power generation system, a water electrolysis hydrogen production system, a hydrogen fuel cell system, an electrochemical energy storage system and a DC load connected with the DC bus through the energy router, the DC bus being connected with an external AC bus through the energy router, the ammonia cracking hydrogen production system and the hydrogen storage system being connected with the external AC bus, the ammonia cracking hydrogen production system and the water electrolysis hydrogen production system being connected with the hydrogen storage system, the hydrogen storage system being connected with the hydrogen fuel cell system, the hydrogen storage system and the electrochemical energy storage system constituting a hybrid energy storage system; the method comprising: obtaining an output power of the photovoltaic power generation system and a power of the DC load, and then determining a charge-discharge power of the hybrid energy storage system; obtaining a SOC value of the electrochemical energy storage system and a SOH value of the hydrogen storage system, and then determining a power distribution control strategy of the microgrid system in combination with the charge-discharge power of the hybrid energy storage system; and adjusting an operation state of the microgrid system according to the power distribution control strategy. The determining of the power distribution control strategy of the microgrid system comprises: when the charge-discharge power of the hybrid energy storage system is greater than zero, determining a first power distribution control strategy in combination with the first relationship and the second relationship, the first power distribution control strategy comprising controlling the electrochemical energy storage system to charge and / or controlling the water electrolysis hydrogen production system to produce hydrogen; and when the charge-discharge power of the hybrid energy storage system is less than zero, determining a second power distribution control strategy in combination with the first relationship and the second relationship, the second power distribution control strategy comprising controlling the electrochemical energy storage system to discharge and / or controlling the hydrogen fuel cell system to generate power. The first power distribution control strategy specifically comprises: setting a difference between the charge-discharge power of the hybrid energy storage system and a rated maximum output power of the electrochemical energy storage system as a second power reference value, controlling the electrochemical energy storage system to charge at the first power reference value, and controlling the water electrolysis hydrogen production system to produce hydrogen at the second power reference value. The microgrid system further comprises a hydrogen load connected with the hydrogen storage system.

2. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 1, wherein, The second power distribution control strategy specifically comprises: setting a difference between the charge-discharge power of the hybrid energy storage system and a rated maximum output power of the hydrogen fuel cell system as a first power reference value, controlling the hydrogen fuel cell system to generate power at the first power reference value, and controlling the electrochemical energy storage system to discharge at a difference between the charge-discharge power of the hybrid energy storage system and the first power reference value. obtaining a normal SOC range of the electrochemical energy storage system and denoted as (SOC min , SOC max ), and determining a first relationship between the SOC value of the electrochemical energy storage system and the normal SOC range; obtaining a normal SOH range of the hydrogen storage system and denoted as (SOH min ,SOH max ), and determining a second relationship between the SOH value of the hydrogen storage system and the normal SOH range; The method further comprises: when the charge-discharge power of the hybrid energy storage system is zero, keeping the operation state of the microgrid system unchanged. 10.A computer device comprising a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the power distribution control method of the microgrid system integrating power-to-hydrogen-to-ammonia according to any one of claims 1 to 9.

3. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 2, wherein, ​ when SOC(t) < SOC min and SOH(t) < SOH min , or when SOC min < SOC max , SOH min < SOH max , and the charge-discharge power of the hybrid energy storage system is greater than or equal to the rated maximum output power of the electrochemical energy storage system, the rated maximum output power of the electrochemical energy storage system is set as a first power reference value, ​ when SOC(t)≤SOC min and SOH min <SOH(t)<SOH max , or when SOC(t)≤SOC min and SOH(t)≥SOH max , or when SOC min <SOC(t)<SOC max and SOH(t)≥SOH max , the charge and discharge power of the hybrid energy storage system is set as a third power reference value, and the electrochemical energy storage system is controlled to charge at the third power reference value; When SOC min < SOC (t) < SOC (t-1) and SOH (t) > SOH (t-1) max , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) min , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) max , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) min , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) max , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) min , or when SOC (t) > SOC (t-1) and SOH (t) < SOH (t-1) max , the water electrolysis hydrogen production system is When SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max and the charge-discharge power of the hybrid energy storage system is less than the rated maximum output power of the electrochemical energy storage system, the electrochemical energy storage system is controlled to charge at the third power reference value. when SOC(t)≥SOC max and SOH(t)≥SOH max , a product of a given accommodation coordination coefficient and the charge-discharge power of the hybrid energy storage system is set as a fourth power reference value, and the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value.

4. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 3, wherein, ​ when SOC(t) < SOC min and SOH(t) > SOH max or when SOC min < SOC(t) < SOC max and SOH(t) > SOH max the hydrogen load is started while the electrochemical energy storage system is controlled to be charged at the third power reference value.

5. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 4, wherein, when SOC(t)≥SOC max and SOH(t)≥SOH max when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SOH when SOC(t)≥SOC and SOH(t)≥SO 6. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 3, wherein, ​ when SOC(t)≤SOC min and SOH(t)≤SOH min , a product of the charge-discharge power of the hybrid energy storage system and a given compensation coordination coefficient is set as a sixth power reference value, and the hydrogen fuel cell system is controlled to generate power at the sixth power reference value; when SOC(t) < SOC min and SOH min < SOH(t) < SOH max , or when SOC(t) < SOC min and SOH(t) > SOH max , or when SOC min > SOC max and SOH(t) > SOH max , the hydrogen fuel cell system is controlled to generate power at the third power reference value. When SOC min <SOC(t)<SOC max And SOH(t)≤SOH min When, or when SOC(t)≥SOC max And SOH(t)≤SOH min At that time, or when SOC min <SOC(t)<SOC max SOH min <SOH(t)<SOH max Furthermore, when the charging and discharging power of the hybrid energy storage system is less than the rated maximum output power of the electrochemical energy storage system, the electrochemical energy storage system is controlled to discharge at the third power reference value. When SOC min SOC(t) < SOC max , SOH min SOH(t) < SOH max , and the charge-discharge power of the hybrid energy storage system is greater than or equal to the rated maximum output power of the electrochemical energy storage system, or when SOC(t) ≥ SOC max and SOH(t) ≥ SOH max , the electrochemical energy storage system is controlled to discharge at the first power reference value, and the hydrogen fuel cell system is controlled to generate electricity at the second power reference value. when SOC(t) ≥ SOC max and SOH min < SOH(t) < SOH max the electrochemical energy storage system is controlled to discharge at the first power reference value.

7. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 6, wherein, when SOC(t)≤SOC min and SOH(t)≤SOH min , the micro-grid system is operated in parallel to make the DC bus obtain DC power, the difference between the charge-discharge power of the hybrid energy storage system and the sixth power reference value is set as a seventh power reference value, the electrochemical energy storage system is controlled to charge at the seventh power reference value, and the ammonia cracking hydrogen production system is controlled to produce hydrogen.

8. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 6, wherein, When SOC min < SOC(t) < SOC max and SOH(t) < SOH min , or when SOC(t) > SOC max and SOH(t) < SOH min , control the ammonia cracking hydrogen production system to produce hydrogen while controlling the electrochemical energy storage system to discharge at the third power reference value.

9. The power distribution control method of a hybrid hydrogen-ammonia microgrid system according to claim 1, wherein, ​ ​

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