A power distribution control method and device for a microgrid system integrating electricity, hydrogen and ammonia

Abstract

The present invention discloses a power distribution control method and device for a microgrid system integrating electricity, hydrogen and ammonia. The microgrid system includes a DC 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 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, and the ammonia cracking hydrogen production system and the hydrogen storage system are both connected to the external AC bus. The method includes: obtaining the output power of the photovoltaic power generation system and the power of the DC load, determining the charge and discharge power of a hybrid energy storage system composed of a hydrogen storage system and an electrochemical energy storage system; obtaining the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system, combining the charge and discharge power of the hybrid energy storage system, and determining a power distribution control strategy to adjust the operating state of the microgrid system. The present invention ensures the stable and safe operation of the microgrid system.

Description

Technical Field

[0001] The present invention relates to the field of microgrid technology, and in particular to a power distribution control method and device for a microgrid system integrating electricity, hydrogen and ammonia. Background Art

[0002] A microgrid system refers to a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, loads, monitoring and protection devices, etc. It is an autonomous system that can achieve self-regulation, protection and management. It can be connected to the external power grid or operate in isolation. Considering the limited capacity of energy storage devices in the microgrid system, how to effectively and dynamically coordinate and control the operating status of related devices in the microgrid system to ensure stable and safe operation of the microgrid system is a technical problem that needs to be solved urgently. Summary of the invention

[0003] The present invention provides a power distribution control method and device for a microgrid system integrating electricity, hydrogen and ammonia, so as to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0004] In a first aspect, a power distribution control method for a microgrid system integrating electric hydrogen and ammonia is provided, wherein the microgrid system comprises a DC 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 DC load connected to the DC bus through the energy router, wherein 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 respectively connected to the external AC bus, the ammonia cracking hydrogen production system and the water electrolysis hydrogen production system are respectively connected to the hydrogen storage system, the hydrogen storage system is connected to the hydrogen fuel cell system, and the hydrogen storage system and the electrochemical energy storage system constitute a hybrid energy storage system; the method comprises:

[0005] Obtaining the output power of the photovoltaic power generation system and the power of the DC load, and then determining the charging and discharging power of the hybrid energy storage system;

[0006] Obtaining the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system, and combining the charge and discharge power of the hybrid energy storage system to determine a power allocation control strategy for the microgrid system;

[0007] According to the power distribution control strategy, the operating state of the microgrid system is adjusted.

[0008] Further, the determining of a power allocation control strategy for the microgrid system includes:

[0009] The normal SOC range of the electrochemical energy storage system is obtained and recorded as (SOC min ,SOC max ), and then determining a first relationship between the SOC value of the electrochemical energy storage system and a normal SOC range;

[0010] Get the normal SOH range of the hydrogen storage system and record it as (SOH min ,SOH max ), and then determining a second relationship between the SOH value of the hydrogen storage system and a normal SOH range;

[0011] When the charge and discharge power of the hybrid energy storage system is greater than zero, combining the first relationship and the second relationship, determining a first power allocation control strategy, which includes controlling the electrochemical energy storage system to charge and / or controlling the water electrolysis hydrogen production system to produce hydrogen;

[0012] When the charge and discharge power of the hybrid energy storage system is less than zero, a second power allocation control strategy is determined in combination with the first relationship and the second relationship, which includes controlling the electrochemical energy storage system to discharge and / or controlling the hydrogen fuel cell system to generate electricity.

[0013] Furthermore, the first power allocation control strategy specifically includes:

[0014] When SOC(t)≤SOC min And SOH(t)≤SOH min When, or when SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max When the charge and 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 to a first power reference value, the difference between the charge and discharge power of the hybrid energy storage system and the rated maximum output power of the electrochemical energy storage system is set to a second power reference value, the electrochemical energy storage system is controlled to charge at the first power reference value, and the water electrolysis hydrogen production system is controlled to produce hydrogen at the second power reference value;

[0015] When SOC(t)≤SOC min And SOH min <SOH(t)<SOH max When SOC(t)≤SOC min And SOH(t)≥SOH max When, or when SOC min <SOC(t)<SOC max And SOH(t)≥SOHmax When the charging and discharging power of the hybrid energy storage system is set to a third power reference value, the electrochemical energy storage system is controlled to be charged at the third power reference value;

[0016] When SOC min <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 When the water electrolysis hydrogen production system is controlled to produce hydrogen at the third power reference value;

[0017] When SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max 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, controlling the electrochemical energy storage system to charge at the third power reference value;

[0018] When SOC(t)≥SOC max And SOH(t)≥SOH max When the product of the charging and discharging power of the hybrid energy storage system and the given consumption coordination coefficient is set to a fourth power reference value, the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value.

[0019] Further, the microgrid system also includes a hydrogen load, and the hydrogen load is connected to the hydrogen storage system;

[0020] When SOC(t)≤SOC min And SOH(t)≥SOH max When, or when SOC min <SOC(t)<SOC max And SOH(t)≥SOH max When the electrochemical energy storage system is controlled to be charged with the third power reference value, the hydrogen load operation is started.

[0021] Furthermore, when SOC(t)≥SOC max And SOH(t)≥SOH maxWhen the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value, the microgrid system is connected to the grid to feed back AC power to the external AC bus, the difference between the charging and discharging power of the hybrid energy storage system and the fourth power reference value is set to a fifth power reference value, the electrochemical energy storage system is controlled to discharge at the fifth power reference value, and the hydrogen load operation is started.

[0022] Furthermore, the second power allocation control strategy specifically includes:

[0023] When SOC(t)≤SOC min And SOH(t)≤SOH min , setting the product of the charging and discharging power of the hybrid energy storage system and the given compensation coordination coefficient as a sixth power reference value, and controlling the hydrogen fuel cell system to generate electricity at the sixth power reference value;

[0024] When SOC(t)≤SOC min And SOH min <SOH(t)<SOH max When SOC(t)≤SOC min And SOH(t)≥SOH max When, or when SOC min <SOC(t)<SOC max And SOH(t)≥SOH max When the hydrogen fuel cell system is controlled to generate electricity at the third power reference value;

[0025] When SOC min <SOC(t)<SOC max And SOH(t)≤SOH min When SOC(t)≥SOC max And SOH(t)≤SOH min When, or when SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH max When 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;

[0026] When SOC min <SOC(t)<SOC max , SOH min <SOH(t)<SOH maxand the charge and 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 When the electrochemical energy storage system is controlled to discharge at the first power reference value, the hydrogen fuel cell system is controlled to generate electricity at the second power reference value;

[0027] When SOC(t)≥SOC max And SOH min <SOH(t)<SOH max When the electrochemical energy storage system is controlled to discharge at the first power reference value.

[0028] Furthermore, when SOC(t)≤SOC min And SOH(t)≤SOH min When the hydrogen fuel cell system is controlled to generate electricity at the sixth power reference value, the microgrid system is connected to the grid so that the DC bus obtains DC power, the difference between the charging and discharging power of the hybrid energy storage system and the sixth power reference value is set to 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.

[0029] Furthermore, when SOC min <SOC(t)<SOC max And SOH(t)≤SOH min When SOC(t)≥SOC max And SOH(t)≤SOH min When the electrochemical energy storage system is controlled to discharge at the third power reference value, the ammonia cracking hydrogen production system is controlled to produce hydrogen.

[0030] Furthermore, the method also includes: when the charging and discharging power of the hybrid energy storage system is zero, maintaining the operating state of the microgrid system unchanged.

[0031] In a second aspect, a computer device is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the power distribution control method of a microgrid system integrating electricity, hydrogen and ammonia as described in the first aspect.

[0032] The present invention has at least the following beneficial effects: by flexibly adjusting the operating state of the microgrid 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 charging and discharging 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 ability of the microgrid system can be improved, and the service life of the electrochemical energy storage system and the hydrogen storage system can be effectively extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0034] Figure 1 It is a schematic diagram of the composition of a microgrid system integrating electricity, hydrogen and ammonia in an embodiment of the present invention;

[0035] Figure 2 It is a flow chart of a power distribution control method of a microgrid system integrating electricity, hydrogen and ammonia in an embodiment of the present invention;

[0036] Figure 3 It is a schematic diagram of the hardware structure of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in an order different from that in the flowchart. The terms "first", "second", etc. in the specification and claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0040] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0041] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all content and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0042] Please refer to Figure 1 , Figure 1 It is a schematic diagram of the composition of a microgrid system integrating electricity, hydrogen and ammonia provided in an embodiment of the present invention, wherein the microgrid 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 to the DC bus via the energy router, wherein 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.

[0043] More specifically, the energy router includes 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 sources and loads of different levels and forms, and can adjust the voltage and current of each converter in real time.

[0044] In practical applications, the photovoltaic power generation system converts the solar energy captured by itself into electrical energy by using the photovoltaic effect. The electrical energy is directly incorporated into the DC bus after being converted by the first DC / DC converter, and can then power the water electrolysis hydrogen production system, the DC load, and can also be stored via the electrochemical energy storage system.

[0045] The electric energy provided by the DC bus is converted into a voltage level by the second DC / DC converter to supply power to the water electrolysis hydrogen production system for consumption, and the hydrogen produced by the water electrolysis hydrogen production system during operation will be stored by the hydrogen storage system, and the hydrogen produced by the ammonia cracking hydrogen production system during operation will also be stored by the hydrogen storage system, and both the hydrogen storage system and the ammonia cracking hydrogen production system are powered by the external AC bus;

[0046] The hydrogen fuel cell system can convert the hydrogen stored in the hydrogen storage system into electrical energy, and then convert the electrical energy into a voltage level through the third DC / DC converter and then merge it into the DC bus to achieve 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;

[0047] The electric energy provided by the DC bus is converted into a voltage level by the bidirectional DC / DC converter and then input into the electrochemical energy storage system for storage to achieve consumption; the electrochemical energy storage system converts the stored electric energy into a voltage level by the bidirectional DC / DC converter and then merges it into the DC bus to achieve compensation;

[0048] The bidirectional DC / AC converter can be understood as a grid-connected port, which is used to achieve AC / DC conversion and bidirectional flow of electric energy between the DC bus and the external AC bus.

[0049] It should be noted that the microgrid system can be deployed in industrial parks, residential areas, isolated power consumption sites and backup sites or other places for use.

[0050] In the microgrid 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 is needed to store or discharge energy, 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 load, which may easily cause the microgrid system to fluctuate or even the micro-source to exit operation. In order to ensure the stable and safe operation of the microgrid system, it is necessary to control the power distribution of each related system contained in the microgrid system according to the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system.

[0051] On this basis, Figure 2 A power distribution control method for a microgrid system integrating electricity, hydrogen and ammonia is provided in an embodiment of the present invention, which specifically includes the following steps:

[0052] Step S110, obtaining the output power of the photovoltaic power generation system and the power of the DC load, and then determining the charging and discharging power of the hybrid energy storage system;

[0053] Wherein, the charging and discharging 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;

[0054] Step S120, obtaining the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system, and then determining the power allocation control strategy for the microgrid system in combination with the charge and discharge power of the hybrid energy storage system;

[0055] Step S130: adjusting the operating state of the microgrid system according to the power allocation control strategy.

[0056] In some embodiments of the present invention, the following description is given with respect to the SOH value of the hydrogen storage system and the SOC value of the electrochemical energy storage system mentioned in the above step S120:

[0057] (1) A hydrogen storage tank is used as the energy storage unit of the hydrogen storage system. 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:

[0058]

[0059] Where, 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 STmax is the maximum internal pressure of the hydrogen storage system, m ST (t) is the hydrogen storage capacity 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 capacity 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 release rate of the hydrogen storage system at time t.

[0060] (2) A lithium battery is used as the energy storage unit of the electrochemical energy storage system, and its mathematical model is:

[0061]

[0062] 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, and can be calculated using the following expression:

[0063]

[0064] In the formula, when the lithium battery is in a charging state, U BAT (t) is the input voltage of the lithium battery, I BAT (t) is the input current of the lithium battery. When the lithium battery is in a discharging state, 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 electrical energy of the lithium battery, I * is the low frequency dynamic current of the lithium battery, A b is the exponential amplitude, B is the exponential time inverse ratio, R resis 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 means that the lithium battery is fully discharged, and when SOC(t)=1, it means that the lithium battery is fully charged.

[0065] In some embodiments of the present invention, the implementation process of step S120 includes but is not limited to the following:

[0066] Step S121, obtaining the SOC value and the normal SOC range of the electrochemical energy storage system, and then determining a first relationship between the SOC value and the normal SOC range of the electrochemical energy storage system;

[0067] The normal SOC range of the electrochemical energy storage system is recorded as (SOC min ,SOC max ), considering the working life and performance of the electrochemical energy storage system, it is preferred to set the minimum SOC limit to SOC min = 0.25 and the maximum SOC limit is SOC max =0.85, the first relationship is SOC(t)≤SOC min or SOC min <SOC(t)<SOC max Or SOC(t)≥SOC max ;

[0068] Step S122, obtaining the SOH value and the normal SOH range of the hydrogen storage system, and then determining a second relationship between the SOH value and the normal SOH range of the hydrogen storage system;

[0069] The normal SOH range of the hydrogen storage system is recorded as (SOH min ,SOH max ), considering the working life and performance of the hydrogen storage system, it is preferred to set the minimum SOH limit to SOH min = 0.2 and the maximum SOH limit is SOH max =0.75, the second relationship is SOH(t)≤SOH min or SOH min <SOH(t)<SOH max Or SOH(t)≥SOH max ;

[0070] Step S123, judging the charging and discharging power of the hybrid energy storage system, specifically:

[0071] The charging and discharging power of the hybrid energy storage system is denoted as P BHF(t), when judging P BHF (t)>0, then execute step S124. BHF (t)<0, then execute step S125. BHF When (t)=0, the operating state of the microgrid system remains unchanged;

[0072] Step S124, determining a first power allocation control strategy according to the first relationship, the second relationship and the charge and 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;

[0073] Step S125, determining a second power allocation control strategy according to the first relationship, the second relationship and the charge and 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.

[0074] Before describing the first power allocation control strategy mentioned in the above step S124 and the second power allocation control strategy mentioned in the above step S125, the following related parameters are set:

[0075] The rated maximum output power of the electrochemical energy storage system is denoted as P BEmax , the rated maximum output power P of the electrochemical energy storage system BEmax Defined as the first power reference value, the charging and discharging power P of the hybrid energy storage system BHF (t) and the rated maximum output power P of the electrochemical energy storage system BEmax The difference between them is defined as the second power reference value, and the charging and discharging power P of the hybrid energy storage system is BHF (t) is defined as the third power reference value, and the charging and discharging power P of the hybrid energy storage system is BHF (t) and the pre-set absorption coordination coefficient k 21 The product between is defined as the fourth power reference value, and the charging and discharging power P of the hybrid energy storage system is BHF The difference between (t) and the fourth power reference value is defined as the fifth power reference value, and the charging and discharging power P of the hybrid energy storage system is BHF (t) and the pre-set compensation coordination coefficient k 22 The product between is defined as the sixth power reference value, and the charging and discharging power P of the hybrid energy storage system is BHF (t) and the sixth power reference value is defined as the seventh power reference value; wherein the absorption coordination coefficient k 21 The value range of is 0.3~0.7, and the compensation coordination coefficient k 22The value range is 0.2~0.8.

[0076] More specifically, the first power allocation control strategy mentioned in the above step S124 can be divided into the following six cases:

[0077] The first case: when SOC(t)≤SOC min And SOH(t)≤SOH min When the electrochemical energy storage system is controlled to charge according to the first power reference value until the SOC value is k 11 (SOC max -SOC min ), k 11 To absorb the SOC adjustment coefficient, k is limited 11 (SOC max -SOC min ) ranges from 0.4 to 0.6 (or k 11 The value range of the electrochemical energy storage system is 0.8 to 1.2. At this time, the power reference value of the electrochemical energy storage system during charging is set to P Bref =P BEmax ; 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 to P Href =P BHF (t)-P BEmax , so as to restore the hydrogen reserve in the hydrogen storage system so that the SOH value of the hydrogen storage system gradually increases;

[0078] As an optional implementation, after controlling the electrochemical energy storage system to charge according to the first power reference value, the ammonia cracking hydrogen production system is directly controlled to produce hydrogen according to the rated maximum output power to restore the hydrogen reserves in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually increases.

[0079] The second case: when SOC(t)≤SOC min And SOH min <SOH(t)<SOH max When the electrochemical energy storage system is controlled to be charged according to the third power reference value, the power reference value of the electrochemical energy storage system during charging is set to P Bref =P BHF (t) to achieve absorption;

[0080] The third case: when SOC(t)≤SOC min And SOH(t)≥SOH max When, or when SOC min <SOC(t)<SOC maxAnd SOH(t)≥SOH max When the electrochemical energy storage system is controlled to be charged according to the third power reference value, the power reference value of the electrochemical energy storage system during charging is set to P Bref =P BHF (t) to achieve absorption; at the same time, controlling the hydrogen load operation so that the SOH value of the hydrogen storage system gradually decreases to a normal SOH range;

[0081] The fourth situation: when SOC min <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 When 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 absorption;

[0082] The fifth situation: when SOC min <SOC(t)<SOC max And SOH min <SOH(t)<SOH max When P BHF (t) <P BEmax , then the electrochemical energy storage system is controlled to be charged 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), in order to achieve absorption; if P BHF (t)≥P BEmax , then the electrochemical energy storage system is first controlled to be charged 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 BEmax , and then control the water electrolysis hydrogen production system to produce hydrogen according to the second power reference value, and set the power reference value of the water electrolysis hydrogen production system during hydrogen production to P Href =P BHF (t)-P BEmax , in order to achieve absorption.

[0083] The sixth case: when SOC(t)≥SOC max And SOH(t)≥SOHmax When 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 absorption;

[0084] At the same time, the following two auxiliary control actions need to be performed: ① Control the microgrid system to connect to the grid, start the bidirectional DC / AC converter to feed back AC power to the external AC bus, 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 during discharge to P Bref =(1-k 21 ) BHF (t), so that the SOC value of the electrochemical energy storage system gradually decreases to within the normal SOC range; ② control the hydrogen load operation to restore the hydrogen reserve in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually decreases to within the normal SOH range.

[0085] More specifically, the second power allocation control strategy mentioned in the above step S125 can be divided into the following six cases:

[0086] The first case: when SOC(t)≤SOC min And SOH(t)≤SOH min , the hydrogen fuel cell system is controlled to generate electricity according to the sixth power reference value, that is, the power reference value of the hydrogen fuel cell system during power generation is set to P Fref =k 22 P BHF (t);

[0087] At the same time, the following two auxiliary control actions need to be performed: ① Control the microgrid system to connect to the grid, start the bidirectional DC / AC converter so that the DC bus obtains DC power, 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 during charging to P Bref =(1-k 22 ) BHF (t), so that the SOC value of the electrochemical energy storage system gradually rises to within 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 reserves in the hydrogen storage system, so that the SOH value of the hydrogen storage system gradually rises to within the normal SOH range.

[0088] The second case: when SOC(t)≤SOC min And SOHmin <SOH(t)<SOH max When SOC(t)≤SOC min And SOH(t)≥SOH max When, or when SOC min <SOC(t)<SOC max And SOH(t)≥SOH max When the hydrogen fuel cell system is controlled to generate electricity according to the third power reference value, the power reference value of the hydrogen fuel cell system during power generation is set to P Fref =P BHF (t) to achieve compensation.

[0089] The third situation: when SOC min <SOC(t)<SOC max And SOH(t)≤SOH min 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, that is, the power reference value of the electrochemical energy storage system during discharge is set to P Bref =P BHF (t) to achieve compensation; at the same time, controlling the ammonia cracking hydrogen production system 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.

[0090] The fourth situation: when SOC min <SOC(t)<SOC max And SOH min <SOH(t)<SOH max When P BHF (t) <P BEmax , then the electrochemical energy storage system is controlled to discharge according to the third power reference value, that is, the power reference value of the electrochemical energy storage system during discharge is set to P Bref =P BHF (t), to achieve compensation; if P BHF (t)≥P BEmax , then the electrochemical energy storage system is first 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 BEmax , and then control the hydrogen fuel cell system to generate electricity according to the second power reference value, that is, set the power reference value of the hydrogen fuel cell system during power generation to P Fref =P BHF (t)-P BEmax, in order to achieve compensation.

[0091] The fifth case: when SOC(t)≥SOC max And SOH min <SOH(t)<SOH max , 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 BEmax , in order to achieve compensation.

[0092] The sixth case: when SOC(t)≥SOC max And SOH(t)≥SOH max When 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 the SOC adjustment coefficient, k is limited 12 (SOC max -SOC min ) ranges from 0.3 to 0.4 (or k 12 The value range of the hydrogen fuel cell system 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 during power generation is set to P Fref =P BHF (t)-P BEmax , so that the SOH value of the hydrogen storage system gradually decreases to a normal SOH range.

[0093] Furthermore, the operation control methods of the electrochemical energy storage system, the water electrolysis hydrogen production system and the hydrogen fuel cell system are specifically described as follows:

[0094] (1) If the electrochemical energy storage system is to be controlled according to the corresponding power reference value P Bref When charging or discharging is performed, 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 first control strategy set in advance is used to control the measured voltage U DC And the reference voltage U DCref The reference voltage U of the electrochemical energy storage system is obtained by analysis Bref , the power reference value P Bref With the reference voltage U Bref Divide to obtain the reference current I of the electrochemical energy storage system Bref, a preset second control strategy is used to control the reference current I Bref And the measured terminal current I B Analyze and obtain the duty cycle u required to control the operation of the electrochemical energy storage system B , control the bidirectional DC / DC converter to the duty cycle u B Responding to change the output power of the electrochemical energy storage system;

[0095] (2) If the water electrolysis hydrogen production system is to be controlled according to the corresponding power reference value P Href To produce hydrogen, the measured terminal voltage U of the water electrolysis hydrogen production system is obtained. H and the measured terminal current I H , the power reference value P Href The measured terminal voltage U H Divide by the phase to obtain the reference current I of the water electrolysis hydrogen production system Href , a preset third control strategy is used to control the reference current I Href And the measured terminal current I H Analyze to obtain the duty cycle u required to control the operation of the water electrolysis hydrogen production system H , control the second DC / DC converter to the duty cycle u H Responding to change the output power of the water electrolysis hydrogen production system;

[0096] (3) If the hydrogen fuel cell system is to be controlled according to the corresponding power reference value P Fref To generate electricity, the actual terminal voltage U of the hydrogen fuel cell system is obtained. F and the measured terminal current I F , the power reference value P Fref The measured terminal voltage U F Divide to obtain the reference current I of the hydrogen fuel cell system Fref , the reference current I is controlled by a fourth control strategy which is preset Fref And the measured terminal current I F Analyze to obtain the duty cycle u required to control the operation of the hydrogen fuel cell system F , control the third DC / DC converter to the duty cycle u F responding to change the output power of the hydrogen fuel cell system;

[0097] The first control strategy, the second control strategy, the third control strategy and the fourth control strategy may be, but are not limited to, existing PID control strategies or fuzzy control strategies or neural network control strategies.

[0098] In the embodiment of the present invention, by flexibly adjusting the operating state of the microgrid 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 charging and discharging 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 ability of the microgrid system can be improved, and the service life of the electrochemical energy storage system and the hydrogen storage system can be effectively extended.

[0099] In addition, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, a power distribution control method of a microgrid system integrating electricity, hydrogen and ammonia in the above embodiment is implemented. Wherein, the computer-readable storage medium includes but is not limited to any type of disk (including floppy disk, hard disk, optical disk, CD-ROM, and magneto-optical disk), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic card or optical card. In other words, 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 disk or an optical disk, etc.

[0100] also, Figure 3 2 is a schematic diagram of the hardware structure of a computer device provided in an embodiment of the present invention, wherein the computer device includes a processor 220, a memory 230, an input unit 240, a display unit 250 and other devices. Those skilled in the art can understand that Figure 3The device structure device shown does not constitute a limitation on all devices, and may include more or fewer components than shown, or combine certain components. The memory 230 can be used to store the computer program 210 and various functional modules, and the processor 220 runs the computer program 210 stored in the memory 230, thereby executing 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 may 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 may include a hard disk, a floppy disk, a U disk, a magnetic tape, etc. The memory 230 disclosed in the embodiment of the present invention includes but is not limited to the above-mentioned types of memory. The memory 230 disclosed in the embodiment of the present invention is only an example and not a limitation.

[0101] The input unit 240 is used to receive the input of the signal and the keyword input by the user. The input unit 240 may include a touch panel and other input devices. The touch panel can collect the user's touch operation on or near it (such as the user's operation on or near the touch panel using any suitable object or accessory such as a finger, stylus, etc.), and drive the corresponding connection device according to a pre-set program; other input devices may include but are not limited to one or more of a physical keyboard, a function key (such as a playback control key, a switch key, etc.), a trackball, a mouse, a joystick, etc. 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 be in the form of a liquid crystal display, an organic light emitting diode, etc. The processor 220 is the control center of the terminal device, which uses various interfaces and lines to connect various parts of the entire device, and executes various functions and processes data by running or executing software programs and / or modules stored in the memory 230, and calling data stored in the memory 230.

[0102] 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 is configured to be executed by the processor 220, and the computer program 210 is configured to execute a power distribution control method for a microgrid system integrating electricity, hydrogen and ammonia in the above-mentioned embodiment.

[0103] The terms "including" and "having" and any variations thereof in the specification of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0104] In the present application, it should be understood that "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural 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, c can be single or multiple.

[0105] Although the description of the present application has been quite detailed and specifically describes several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but should be regarded as providing a broad possible interpretation of these claims by reference to the attached claims, taking into account the prior art, so as to effectively cover the intended scope of the present application. In addition, the above description of the present application is based on the embodiments foreseeable by the inventor, and its purpose is to provide a useful description, and those non-substantial changes to the present application that have not yet been foreseen may still represent equivalent changes to the present application.

Claims

1. A power distribution control method for a microgrid system integrating electricity, hydrogen and ammonia, characterized in that: The microgrid system comprises a DC 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 DC load connected to the DC bus via the energy router. The DC bus is connected to an external AC bus via the energy router, the ammonia cracking hydrogen production system and the hydrogen storage system are respectively connected to the external AC bus, the ammonia cracking hydrogen production system and the water electrolysis hydrogen production system are respectively connected to the hydrogen storage system, the hydrogen storage system is connected to the hydrogen fuel cell system, and the hydrogen storage system and the electrochemical energy storage system constitute a hybrid energy storage system. The method comprises: Obtaining the output power of the photovoltaic power generation system and the power of the DC load, and then determining the charging and discharging power of the hybrid energy storage system; Obtaining the SOC value of the electrochemical energy storage system and the SOH value of the hydrogen storage system, and combining the charge and discharge power of the hybrid energy storage system to determine a power allocation control strategy for the microgrid system; According to the power distribution control strategy, the operating state of the microgrid system is adjusted; Wherein, the determining of the power allocation control strategy for the microgrid system includes: The normal SOC range of the electrochemical energy storage system is obtained and recorded as , and then determining a first relationship between the SOC value of the electrochemical energy storage system and a normal SOC range; Get the normal SOH range of the hydrogen storage system and record it as , and then determining a second relationship between the SOH value of the hydrogen storage system and a normal SOH range; When the charge and discharge power of the hybrid energy storage system is greater than zero, combining the first relationship and the second relationship, determining a first power allocation control strategy, which includes controlling the electrochemical energy storage system to charge and / or controlling the water electrolysis hydrogen production system to produce hydrogen; When the charge and discharge power of the hybrid energy storage system is less than zero, combining the first relationship and the second relationship, determining a second power allocation control strategy, which includes controlling the electrochemical energy storage system to discharge and / or controlling the hydrogen fuel cell system to generate electricity; The first power allocation control strategy specifically includes: when and when , When the charge and 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 to a first power reference value, the difference between the charge and discharge power of the hybrid energy storage system and the rated maximum output power of the electrochemical energy storage system is set to a second power reference value, the electrochemical energy storage system is controlled to charge at the first power reference value, and the water electrolysis hydrogen production system is controlled to produce hydrogen at the second power reference value; when and when and when and When the charging and discharging power of the hybrid energy storage system is set to a third power reference value, the electrochemical energy storage system is controlled to be charged at the third power reference value; when and when and when and When the water electrolysis hydrogen production system is controlled to produce hydrogen at the third power reference value; when , 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, controlling the electrochemical energy storage system to charge at the third power reference value; when and When the product of the charging and discharging power of the hybrid energy storage system and the given consumption coordination coefficient is set to a fourth power reference value, the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value.

2. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 1 is characterized in that: The microgrid system further includes a hydrogen load, which is connected to the hydrogen storage system; when and when and When the electrochemical energy storage system is controlled to be charged with the third power reference value, the hydrogen load operation is started.

3. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 2 is characterized in that: when and When the water electrolysis hydrogen production system is controlled to produce hydrogen at the fourth power reference value, the microgrid system is connected to the grid to feed back AC power to the external AC bus, the difference between the charging and discharging power of the hybrid energy storage system and the fourth power reference value is set to a fifth power reference value, the electrochemical energy storage system is controlled to discharge at the fifth power reference value, and the hydrogen load operation is started.

4. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 1 is characterized in that: The second power allocation control strategy specifically includes: when and , setting the product of the charging and discharging power of the hybrid energy storage system and the given compensation coordination coefficient as a sixth power reference value, and controlling the hydrogen fuel cell system to generate electricity at the sixth power reference value; when and when and when and When the hydrogen fuel cell system is controlled to generate electricity at the third power reference value; when and when and when , When 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; when , and the charging and discharging 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 and When the electrochemical energy storage system is controlled to discharge at the first power reference value, the hydrogen fuel cell system is controlled to generate electricity at the second power reference value; when and When the electrochemical energy storage system is controlled to discharge at the first power reference value.

5. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 4 is characterized in that: when and When the hydrogen fuel cell system is controlled to generate electricity at the sixth power reference value, the microgrid system is connected to the grid so that the DC bus obtains DC power, the difference between the charging and discharging power of the hybrid energy storage system and the sixth power reference value is set to 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.

6. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 4 is characterized in that: when and when and When the electrochemical energy storage system is controlled to discharge at the third power reference value, the ammonia cracking hydrogen production system is controlled to produce hydrogen.

7. The power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia according to claim 1 is characterized in that: The method also includes: when the charging and discharging power of the hybrid energy storage system is zero, maintaining the operating state of the microgrid system unchanged.

8. A computer device comprising a memory and a processor, wherein a computer program is stored in the memory, wherein: The processor executes the computer program to implement the power distribution control method of the microgrid system integrating electricity, hydrogen and ammonia as described in any one of claims 1 to 7.

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