A state machine-based integrated energy system control method

Abstract

The present invention relates to the technical field of energy management of integrated energy systems, and relates to a method for controlling an integrated energy system based on a state machine. On the one hand, an integrated energy system is provided, including many system components such as a photovoltaic power generation module, a battery, a power hub, an electrolysis hydrogen production and storage module, a hydrogen storage tank, a fuel cell power generation module, a waste heat recovery module, a power grid, a thermal power user and an energy management controller; on the other hand, an method for controlling energy management of an integrated energy system based on a state machine is provided, including operating load information of each module in the integrated energy system, and state information of the operation of the integrated energy system based on the state machine under different scenario working conditions. The present invention comprehensively considers various factors, optimizes the integrated energy system according to the actual operating load information of each module, establishes an integrated energy system operation optimization model, realizes effective conversion between energy sources such as electricity, hydrogen and heat, and improves the comprehensive energy utilization rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy control of integrated energy systems, and in particular relates to an integrated energy system control method based on a state machine. Background Art

[0002] Integrated energy systems have experienced rapid development over the past decade, but due to a lack of synergy, they are generally characterized by "over-integration but insufficient intelligence." To support the transformation of integrated energy systems, it is urgent to focus on the collaborative energy control of energy management systems and develop energy management and control methods for integrated energy systems.

[0003] Energy management and control methods for integrated energy systems based on state machines are divided into two parts: integrated energy system design and state-machine-based energy management and control strategies. An integrated energy system utilizes advanced physical information technology and innovative management models to integrate multiple energy sources within a region, such as renewable energy, electricity, and thermal energy, to achieve coordinated planning, optimized operation, collaborative management, interactive response, and mutual assistance among multiple heterogeneous energy subsystems. This new integrated energy system aims to effectively improve energy efficiency and promote sustainable energy development while meeting diverse energy demands within the system. The state-machine-based energy management and control strategy uses the integrated energy system as the control layer and the state machine as the control foundation. Within different energy storage operating ranges, combined with the varying range of load-side electricity and heat demand, it determines the input and output states of each component of the integrated energy system. It then plans the system's different operating states, compares them with the energy storage operating states and load demand under actual operating conditions, and finally adjusts the operating conditions of each system component according to the designed state rules. However, most existing research focuses solely on the design of integrated energy systems. Research on state-machine-based energy control methods for integrated energy systems is very limited, and current energy management strategies are relatively inefficient.

[0004] Therefore, technical personnel in this field are committed to developing an energy management and control method for an integrated energy system based on a state machine to achieve effective utilization of renewable energy, electrical energy, and thermal energy in the integrated energy system, improve the energy utilization efficiency of the integrated energy system, and improve the coupling method of various energy forms such as renewable energy, energy storage, electrical energy, and thermal energy. Summary of the Invention

[0005] In light of the aforementioned shortcomings of the existing technology, the present invention provides a state-machine-based energy management and control method for an integrated energy system. This method fully considers the various operational states of the integrated energy system and efficiently and clearly identifies the operating ranges for each state. Furthermore, it can accurately and rapidly adjust the system's operating conditions according to the designed state rules, taking into account the various energy demands on the load side.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a state machine-based integrated energy system control method, wherein the integrated energy system includes a photovoltaic power generation module, a battery, a power hub, an electrolytic hydrogen production and storage module, a hydrogen storage tank, a fuel cell power generation module, a waste heat recovery module, a power grid, a thermal power user and an energy management controller; the output ends of the photovoltaic power generation module, the battery, and the fuel cell power generation module are all connected to the power hub, the power grid and the power hub are bidirectionally connected, the output end of the power hub is connected to the input end of the electrolytic hydrogen production and storage module, the electrolytic hydrogen production and storage module, the hydrogen storage tank and the fuel cell power generation module are connected in sequence, the fuel cell power generation module is connected to the waste heat recovery module, the thermal power user is respectively connected to the power hub and the waste heat recovery module, the energy management controller is respectively connected to the power hub, the hydrogen storage tank, the waste heat recovery module and the thermal power user, and hydrogen energy is used preferentially;

[0007] The energy management controller performs state machine-based energy management control on each module of the integrated energy system according to the photovoltaic power generation PV of the photovoltaic power generation module, the power generation FC of the fuel cell module, the power consumption EL of the water electrolysis hydrogen production module and the hydrogen storage capacity HS of the hydrogen storage module, the heat recovered HT of the waste heat utilization module, the battery power BT, the current charge rate SOC of the battery, the grid-connected power Grid, the excess power EE and the user-side power demand Load; and is divided into energy storage mode and energy consumption mode according to the operating conditions when the power generation PV of the photovoltaic power generation module is greater than the user-side power demand Load and when the power generation PV of the photovoltaic power generation module is less than the user-side power demand Load.

[0008] The photovoltaic power generation module and the fuel cell power generation module are power generation modules of the integrated energy system. The photovoltaic power generation module generates electricity using photovoltaic renewable energy, and the fuel cell module generates electricity using hydrogen produced by the electrolysis hydrogen production and storage module.

[0009] The electrolytic hydrogen production and storage module, the waste heat recovery module and the battery are energy storage modules of the integrated energy system. The electrolytic hydrogen production and storage module produces hydrogen by utilizing the excess electricity of the power generation module and stores the energy in the hydrogen; the waste heat utilization module fully recovers the heat generated during the power generation process of the power generation module into the hot water storage tank or refrigeration system through the cooling water circuit; the battery provides balanced and stable power output for the power generation module and the user-side power demand, while storing excess electricity.

[0010] When the power grid is in the off-peak period, the integrated energy utilization system is in the energy storage mode, which includes the following three states:

[0011] State 1: When the hydrogen amount HS in the hydrogen storage tank is less than the first hydrogen storage threshold, the grid power Grid supplies the sum of the user-side power demand Load and the power consumption EL of the water electrolysis hydrogen production module during the off-peak period;

[0012] State 2: when the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is greater than the third current charge rate threshold, the grid power Grid supplies the user-side power demand Load during the off-peak period;

[0013] State 3: When the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is less than the third current charge rate threshold, the grid power Grid supplies the sum of the user-side power demand Load and the battery module power BT during the off-peak period.

[0014] When the power grid is in peak period, the integrated energy utilization system is in energy consumption mode. The energy consumption mode is divided into low energy consumption mode and high energy consumption mode according to the high and low periods of power consumption on the user side. The low energy consumption mode includes the following four states:

[0015] State 4: When the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging;

[0016] State 5: When the photovoltaic power generation PV is greater than the user-side load demand Load and the battery current charge rate SOC is less than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load and the battery charge BT;

[0017] State 6: when the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than a second current charge rate threshold, the photovoltaic power generation PV and the battery discharge capacity BT supply the user-side load demand Load;

[0018] State 7: When the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than a second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging.

[0019] When the power grid is in peak period, the integrated energy utilization system is in energy consumption mode. The energy consumption mode is divided into low energy consumption mode and high energy consumption mode according to the high and low periods of power consumption on the user side. The high energy consumption mode includes the following 10 states:

[0020] State 8: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging;

[0021] State 9: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the photovoltaic power generation PV supplies the sum of the user-side load demand Load and the battery charge capacity BT;

[0022] State 10: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the photovoltaic power generation PV and the battery discharge capacity BT supply the user-side load demand Load;

[0023] State 11: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than the second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging;

[0024] State 12: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the fuel cell power generation FC is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the fuel cell power generation FC is supplied to the user-side load demand Load, and the excess power EE can be supplied to the electric heating heat storage;

[0025] State 13: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the fuel cell power generation FC is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC supplies the sum of the user-side load demand Load and the battery charge capacity BT;

[0026] State 14: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV, and the battery discharge BT;

[0027] State 15: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV and the grid power Grid;

[0028] State 16: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the battery charge BT;

[0029] State 17: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the excess power EE.

[0030] The first hydrogen storage threshold is 90% of the total hydrogen storage capacity of the hydrogen storage tank; the third current charge rate threshold is 70% of the total charge rate of the battery.

[0031] The first hydrogen storage threshold is 90% of the total hydrogen storage capacity of the hydrogen storage tank, and the first current charge rate threshold is 99% of the total charge rate of the battery.

[0032] The second hydrogen storage threshold is 10% of the total hydrogen storage capacity of the hydrogen storage tank, and the second current charge rate threshold is 10% of the total charge rate of the battery.

[0033] When the ambient temperature and light intensity change, the four performance parameters of the photovoltaic array, namely the open circuit voltage and current, and the voltage and current at maximum power, are directly corrected. The voltage and current correction coefficients are:

[0034]

[0035] ΔU=[1-c(TT r )]ln[e+b(SS r )]

[0036] Where S and T represent the light intensity and ambient temperature, S and T r It represents the reference light intensity and ambient temperature under standard conditions, a and c are temperature compensation coefficients, b is the light intensity compensation coefficient, and the four performance parameters are converted into:

[0037]

[0038] The performance parameters corrected by environmental influences can better meet actual requirements. At the same time, the photovoltaic output maximum power point is followed by control, so that photovoltaic power generation can operate stably near the maximum power point.

[0039] The battery SOC is calculated as follows:

[0040]

[0041] where Q t Indicates the remaining battery power, Q n Represents the total charge of the battery, and the battery SOC is estimated using the initial state SOC0 and the time integral of charge and discharge i(t).

[0042] Compared with the prior art, the beneficial effects of the present invention are: it comprehensively considers the actual electricity demand on the user side, photovoltaic dynamic power generation, battery charge state, hydrogen storage tank hydrogen storage capacity, fuel cell power generation, electrolysis hydrogen production power consumption and other state variables during the operation of the integrated energy system, and controls the state switching of energy management, thereby realizing the maximum utilization of hydrogen energy, electrical energy and thermal energy. By switching between different control strategy states, the integrated energy system makes full use of renewable energy, and uses batteries and electric hydrogen conversion devices to store and release energy. A large amount of heat in the fuel cell power generation process is fully recovered through the waste heat recovery module, so that the system's comprehensive energy efficiency is above 70%. At the same time, the entire process is clean, the system has a high specific energy, and the equipment is small in size. While protecting the environment, it makes full use of various resources to meet users' needs for electricity and heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of a comprehensive energy system of the present invention;

[0044] Figure 2 This is a workflow diagram of an energy management control strategy for an integrated energy system according to the present invention;

[0045] Figure 3 It is the energy storage mode under the energy management control strategy of the integrated energy system of the present invention;

[0046] Figure 4 It is a low energy consumption mode under the energy management control strategy of the integrated energy system of the present invention;

[0047] Figure 5 It is a high energy consumption mode under the energy management control strategy of the integrated energy system of the present invention;

[0048] Figure 6 is the typical daily user load curve in the example of the present invention;

[0049] Figure 7 is the photovoltaic power generation curve in the example of the present invention;

[0050] Figure 8 is the charge and discharge power variation curve of the battery module in the calculation example of the present invention;

[0051] Figure 9 is the power change curve of the grid connected in the example of the present invention;

[0052] Figure 10 is the battery state of charge change curve in the example of the present invention;

[0053] Figure 11 is the hydrogen storage capacity variation curve of the hydrogen storage tank in the calculation example of the present invention;

[0054] Figure 12 is the power consumption curve of the electrolytic cell module in the example of the present invention;

[0055] Figure 13 is the power generation curve of the fuel cell module in the example of the present invention;

[0056] In the attached figure, 1-photovoltaic power generation module, 2-battery, 3-power hub, 4-electrolysis hydrogen production and storage module, 5-hydrogen storage tank, 6-fuel cell power generation module, 7-waste heat recovery module, 8-grid, 9-thermal power user, 10-energy management controller. DETAILED DESCRIPTION

[0057] The drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate the embodiments, some components in the drawings may be omitted, enlarged, or reduced in size, and do not represent actual product dimensions. Those skilled in the art will understand that some well-known structures and their descriptions may be omitted from the drawings. The positional relationships depicted in the drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0058] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0059] The present invention will be further described in detail below with reference to specific embodiments of the present invention.

[0060] like Figure 1 As shown, a comprehensive energy system includes a photovoltaic power generation module 1, a battery 2, a power hub 3, an electrolytic hydrogen production and storage module 4, a hydrogen storage tank 5, a fuel cell power generation module 6, a waste heat recovery module 7, a power grid 8, a thermal power user 9 and an energy management controller 10; the output ends of the photovoltaic power generation module 1, the battery 2, and the fuel cell power generation module 6 are all connected to the power hub 3, the power grid 8 and the power hub 3 are bidirectionally connected, the output end of the power hub 3 is connected to the input end of the electrolytic hydrogen production and storage module 4, the electrolytic hydrogen production and storage module 4, the hydrogen storage tank 5 and the fuel cell power generation module 6 are connected in sequence, the fuel cell power generation module 6 is connected to the waste heat recovery module 7, the thermal power user 9 is respectively connected to the power hub 3 and the waste heat recovery module 7, and the energy management controller 10 is respectively connected to the power hub 3, the hydrogen storage tank 5, ... The heat recovery module 7 is connected to the thermal power user 9; the photovoltaic power generation module and the fuel cell power generation module are the power generation modules of the integrated energy system, the photovoltaic power generation module uses photovoltaic renewable energy to generate electricity, and the fuel cell module uses the hydrogen generated by the electrolysis hydrogen production and storage module to generate electricity; the electrolysis hydrogen production and storage module, the waste heat utilization module and the battery are the energy storage modules of the integrated energy system, the electrolysis hydrogen production and storage module produces hydrogen by using the excess electricity of the power generation module, and stores energy in the hydrogen; the waste heat utilization module fully recovers the heat generated during the power generation process of the power generation module into the hot water storage tank or the refrigeration system through the cooling water circuit; the battery provides balanced and stable power output for the power generation module and the user-side power demand, and stores excess electricity at the same time;

[0061] In this embodiment, the integrated energy system transmits instructions to the power hub 3 through the operating conditions of the battery 2, the hydrogen storage tank 5 and the thermal power user 9 through the energy management controller 10 to control the fuel cell power generation module 6 and the electrolysis hydrogen production and storage module 4, adjust the operating conditions of different components, and then optimize the energy management control strategy of the entire integrated energy system to achieve an improvement in the overall efficiency of the integrated energy system.

[0062] like Figure 2As shown, the present invention provides an energy management and control method for an integrated energy system based on a state machine, including operating load information of each module in the integrated energy system, and state information of the integrated energy system operation based on the state machine under different scenario working conditions; wherein, the operating load information of each module in the integrated energy system includes photovoltaic power generation (PV) of the photovoltaic power generation module, power generation (FC) of the fuel cell module, power consumption (EL) of the electrolysis hydrogen production module and hydrogen storage (HS) of the hydrogen storage module, heat recovery (HT) of the waste heat utilization module, battery power (BT), current charge rate (SOC) of the battery, grid-connected power (Grid), excess power (EE) and user-side power demand (Load); divided into the following Figure 3 The state control method of the energy consumption mode shown and Figure 4 The state control method of the energy storage mode shown is as follows:

[0063] like Figure 3 As shown, the grid period is judged. When the grid operation period is the valley period, it means that the integrated energy system is in the energy storage state:

[0064] In the energy storage state, when the hydrogen amount HS in the hydrogen storage tank is less than the first hydrogen storage threshold, the grid power Grid supplies the sum of the user-side power demand Load and the power consumption EL of the water electrolysis hydrogen production module during the off-peak period;

[0065] In the energy storage state, when the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is greater than the third current charge rate threshold, the grid power Grid supplies the user-side power demand Load during the off-peak period;

[0066] In the energy storage state, when the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is less than the third current charge rate threshold, the grid power Grid supplies the sum of the user-side power demand Load and the battery module power BT during the off-peak period;

[0067] like Figure 4 As shown, the power consumption period is judged. When the power consumption period is a high power consumption period, it means that the integrated energy system is in a low energy consumption state:

[0068] In the low energy consumption state, when the photovoltaic power generation PV is greater than the user-side load demand Load, and the current charge rate SOC of the battery is greater than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging;

[0069] In the low energy consumption state, when the photovoltaic power generation PV is greater than the user-side load demand Load and the battery current charge rate SOC is less than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load and the battery charge BT;

[0070] In the low energy consumption state, when the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than a second current charge rate threshold, the photovoltaic power generation PV and the battery discharge amount BT supply the user-side load demand Load;

[0071] In the low energy consumption state, when the photovoltaic power generation PV is less than the user-side load demand Load, and the current charge rate SOC of the battery is less than a second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging;

[0072] like Figure 5 As shown, the power consumption period is judged. When the power consumption period is a low power consumption period, it means that the integrated energy system is in a high energy consumption state:

[0073] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the current charge rate SOC of the battery is greater than the first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging;

[0074] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the photovoltaic power generation PV supplies the sum of the user-side load demand Load and the battery charge capacity BT;

[0075] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the photovoltaic power generation PV and the battery discharge amount BT supply the user-side load demand Load;

[0076] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the current charge rate SOC of the battery is less than the second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging;

[0077] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the power generation FC of the fuel cell is greater than the user-side load demand Load, and the current charge rate SOC of the battery is greater than the first current charge rate threshold, the power generation FC of the fuel cell is supplied to the user-side load demand Load, and the excess power EE can be supplied to the electric heating heat storage;

[0078] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the fuel cell power generation FC is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC supplies the sum of the user-side load demand Load and the battery charge capacity BT;

[0079] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV and the battery discharge BT;

[0080] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV and the grid power Grid;

[0081] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the battery charge BT;

[0082] In the high energy consumption state, when the hydrogen amount HS of the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the excess electricity EE;

[0083] Based on the control method of the present invention, the mathematical model of each module in the integrated energy system is used for calculation and control. The mathematical model of the photovoltaic power generation module is: the relationship between the voltage and current of the photovoltaic semiconductor can be obtained, and the basic output characteristics of photovoltaic power generation are:

[0084]

[0085]

[0086]

[0087] Where U is the output voltage, I is the output current, C1 and C2 are correction coefficients, and U m is the voltage corresponding to the maximum power, U oc is the open circuit voltage, I m is the current corresponding to the maximum power, I sc is the open circuit current.

[0088] As ambient temperature and light intensity change, photovoltaic power generation output will also change accordingly. This paper uses a method to correct photovoltaic array performance parameters to establish a behavioral model. When the ambient temperature and light intensity change, the four performance parameters of the photovoltaic array are directly corrected: open circuit voltage and current, voltage and current at maximum power. The voltage and current correction coefficients are:

[0089] As ambient temperature and light intensity change, photovoltaic power generation output will also change accordingly. This invention uses a method to correct photovoltaic array performance parameters to establish a behavioral model. When the ambient temperature and light intensity change, the four performance parameters of the photovoltaic array are directly corrected: open circuit voltage and current, voltage and current at maximum power. The voltage and current correction coefficients are:

[0090]

[0091] ΔU=[1-c(TT r )]ln[e+b(SS r )]

[0092] Where S and T represent the light intensity and ambient temperature, S and T rIt represents the reference light intensity and ambient temperature under standard conditions, a and c are temperature compensation coefficients, and b is the light intensity compensation coefficient. The four performance parameters can be converted into:

[0093]

[0094] The performance parameters corrected by environmental influences can better meet actual requirements. At the same time, photovoltaic output requires MPPT control so that photovoltaic power generation can operate stably near the maximum power point.

[0095] The mathematical model of the electrolytic cell module is as follows:

[0096] The electrolytic cell converts electrical energy into chemical energy and stores it in hydrogen. The present invention focuses on the input electrical energy and gas volume of the electrolytic cell. The voltage of the electrolytic cell can be expressed in terms of open circuit voltage, activation overvoltage, ohmic overvoltage, and concentration overvoltage:

[0097]

[0098] Among them U rev is the reversible voltage, T is the electrolytic cell temperature, U p is the overvoltage caused by the pressure difference between reactants and products, is the hydrogen partial pressure at the cathode of the electrolyzer, is the oxygen partial pressure at the anode of the electrolyzer, is the water pressure, U act is the activation overvoltage, i EL is the working current density of the electrolytic cell, i A,0 is the anode-cathode exchange current density, i C,0 is the anode-cathode charge transfer coefficient, U dif is the concentration overvoltage, are the concentrations of hydrogen and oxygen, is the concentration of hydrogen and oxygen under standard conditions, U ohm is the ohmic overvoltage, is the ionic conductivity, A is the activation area, R ohm is the ohmic resistance of the conductor.

[0099] The mathematical model of the battery module is as follows:

[0100]

[0101] Where R0 is the equivalent series resistance of the battery, R1 and R2 are the equivalent parallel resistances, C1 and C2 are the equivalent parallel capacitors, U1 and U2 are the voltages across the equivalent capacitors, and I and U are the output or input current and voltage.

[0102] During the operation of the system distribution network, the SOC estimation of the battery plays a very important role. In the present invention, the battery SOC is calculated as follows:

[0103]

[0104] where Q t Indicates the remaining battery power, Q n Represents the total charge of the battery. Since the remaining charge is difficult to obtain, the battery SOC is usually estimated by using the initial state SOC0 and the time integral of the charge and discharge i(t).

[0105] The mathematical model of the fuel cell power generation module is as follows:

[0106]

[0107] Among them is Anode hydrogen partial pressure, is the cathode oxygen partial pressure, T is the temperature of the PEMFC stack, RH a is the anode humidity, RH c is the cathode humidity, i is the current density, is the saturated vapor pressure, P a is the cathode pressure, and is the oxygen concentration mass fraction and hydrogen concentration mass fraction, i max is the limiting current density.

[0108] The mathematical model of the waste heat recovery module is as follows:

[0109]

[0110] Among them, M st is the mass of the battery stack, C st is the specific heat capacity of the stack, T st 、T st0 are the stack temperature and the initial stack temperature, Q total Q is the total energy theoretically generated by the stack during the reaction process, ele is the power generation power of the battery stack, Q dis The heat energy dissipated by the battery stack, is the anode hydrogen consumption rate, is the consumption rate of cathode oxygen, is the generation rate of cathode water, N is the number of cells, I st is the stack current, F is the Faraday constant, is the unit hydrogen enthalpy, is the molar mass of hydrogen at the anode inlet, is the molar mass of water vapor at the anode inlet, is the molar mass of the air at the cathode inlet, is the molar mass of water vapor at the cathode inlet, is the molar mass of hydrogen at the anode outlet, is the molar mass of water vapor at the anode outlet, Molar mass of oxygen at cathode outlet, Molar mass of nitrogen at cathode outlet, Molar mass of water vapor at cathode outlet, Molar mass of liquid water at cathode outlet, T0 is the Kelvin temperature corresponding to the anode inlet, cathode inlet, anode outlet, cathode outlet and environment respectively.

[0111] The mathematical model of the hydrogen storage tank is as follows:

[0112]

[0113] Where P1 is the real-time pressure of the hydrogen storage tank, P0 is the initial pressure of the hydrogen storage tank, is the hydrogen flow rate, R is the gas constant, T H is the hydrogen storage tank temperature, V H is the volume of the hydrogen storage tank, and z is the hydrogen compression constant.

[0114] like Figure 6 As shown, the daily load curve in the figure is the daily variation curve of the user-side load demand Load in the calculation example of the present invention. The average load power on a typical day is about 1kW, the peak load is 2-2.5kW, and the minimum instantaneous load is 80W-150W. According to the user-side load demand, the parameters of each component can be calculated according to the system control strategy and the mathematical model of each component described in the present invention;

[0115] like Figure 7 As shown, in the calculation example of the present invention, the voltage and current parameters of the photovoltaic power generation mathematical model are combined, and the photovoltaic power generation mathematical model is used to calculate the photovoltaic power generation power daily variation curve in the figure, which is the photovoltaic power generation PV variation curve of the present invention;

[0116] like Figure 8 As shown, combined with the user-side load demand Load and the photovoltaic power generation PV, as well as the state machine-based system control strategy and battery mathematical model described in the present invention, the charging and discharging BT power change curve of the battery module in the calculation example of the present invention is obtained, where a positive value indicates battery charging and a negative value indicates battery discharging;

[0117] like Figure 9As shown, based on the state machine-based system control strategy described in the present invention, according to the change curves of the user-side load demand Load, the photovoltaic power generation PV, the battery module charge and discharge BT, the fuel cell power generation FC, and the electrolysis water hydrogen production power consumption EL, the grid power Grid change curve in the calculation example of the present invention can be obtained;

[0118] like Figure 10 The figure shows the battery state of charge (SOC) curve in the example of the present invention. On a typical day, the battery SOC returns to or is slightly higher than the initial position after a day's cycle, thus enabling continuous operation of the system between typical days.

[0119] like Figure 11 As shown in FIG. , it is a curve showing the change of the hydrogen storage capacity HS of the hydrogen storage tank in the calculation example of the present invention. On a typical day, the hydrogen storage capacity HS of the hydrogen storage tank can return to the initial position or slightly higher than the initial position after a day's cycle, so that the system can be continuously operated between typical days.

[0120] like Figure 12 As shown, it is the curve of the power consumption EL of the electrolytic cell module in the calculation example of the present invention. The electrolytic cell works normally to store hydrogen during valley electricity prices until the hydrogen storage reaches saturation and stops.

[0121] like Figure 13 As shown, it is the power generation power FC change curve of the fuel cell module in the calculation example of the present invention. The fuel cell works normally between 6 and 9 o'clock and between 15 and 22 o'clock.

[0122] Through the above embodiments, the technical solution of the present invention can realize the optimized control of energy management of the integrated energy system. The solution can realize the effective conversion between energy sources and improve the energy utilization rate.

[0123] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention can be made by one of ordinary skill in the art without inventive effort. Therefore, any technical solution that can be derived by one of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A state machine-based integrated energy system control method, characterized by: The integrated energy system comprises a photovoltaic power generation module (1), a storage battery (2), a power hub (3), an electrolytic hydrogen production and storage module (4), a hydrogen storage tank (5), a fuel cell power generation module (6), a waste heat recovery module (7), a power grid (8), a thermal power user (9) and an energy management controller (10); the output ends of the photovoltaic power generation module (1), the storage battery (2) and the fuel cell power generation module (6) are all connected to the power hub (3), the power grid (8) and the power hub (3) are bidirectionally connected, the output end of the power hub (3) is connected to the input end of the electrolytic hydrogen production and storage module (4), the electrolytic hydrogen production and storage module (4), the hydrogen storage tank (5) and the fuel cell power generation module (6) are connected in sequence, the fuel cell power generation module (6) is connected to the waste heat recovery module (7), the thermal power user (9) is respectively connected to the power hub (3) and the waste heat recovery module (7), the energy management controller (10) is respectively connected to the power hub (3), the hydrogen storage tank (5), the waste heat recovery module (7) and the thermal power user (9), and hydrogen energy is used preferentially; The energy management controller (10) performs state machine-based energy management control on each module of the integrated energy system according to the photovoltaic power generation PV of the photovoltaic power generation module, the power generation FC of the fuel cell module, the power consumption EL of the water electrolysis hydrogen production module, the hydrogen storage HS of the hydrogen storage module, the heat recovered HT of the waste heat utilization module, the battery power BT, the current charge rate SOC of the battery, the grid-connected power Grid, the excess power EE and the user-side power demand Load; the system is divided into an energy storage mode and an energy consumption mode according to the operating conditions when the photovoltaic power generation PV of the photovoltaic power generation module is greater than the user-side power demand Load and when the photovoltaic power generation PV of the photovoltaic power generation module is less than the user-side power demand Load; when the ambient temperature and light intensity change, the four performance parameters of the photovoltaic array, namely, the open circuit voltage and current, and the voltage and current at maximum power, are directly corrected, and the voltage and current correction coefficients are: In the formula S and T Indicates light intensity and ambient temperature, S r and T r Respectively represent the reference light intensity and ambient temperature under standard conditions, a and c is the temperature compensation coefficient, b is the light intensity compensation coefficient, and the four performance parameters are converted into: Where, U is the output voltage, I is the output current, C 1 and C 2 is the correction factor, U m is the voltage corresponding to the maximum power, U oc is the open circuit voltage, I m is the current corresponding to the maximum power, I sc is the open circuit current; is the voltage correction factor and is the current correction factor; The performance parameters corrected by environmental influences can better meet actual requirements. At the same time, the photovoltaic output maximum power point is followed by control, so that photovoltaic power generation can operate stably at the maximum power point.

2. The state machine-based integrated energy system control method according to claim 1, characterized in that: The photovoltaic power generation module (1) and the fuel cell power generation module (6) are power generation modules of the integrated energy system. The photovoltaic power generation module (1) generates electricity using photovoltaic renewable energy, and the fuel cell module (6) generates electricity using hydrogen generated by the electrolytic hydrogen production and storage module. The electrolytic hydrogen production and storage module, the waste heat recovery module (7) and the battery (2) are energy storage modules of the integrated energy system. The electrolytic hydrogen production and storage module produces hydrogen by utilizing the excess power of the power generation module and stores energy in the hydrogen; the waste heat utilization module fully recovers the heat generated during the power generation process of the power generation module into a hot water storage tank or a refrigeration system through a cooling water circuit; the battery (2) provides balanced and stable power output for the power generation module and the user side power demand, and stores excess power at the same time.

3. The state machine-based integrated energy system control method according to claim 1, characterized in that: When the power grid is in the off-peak period, the integrated energy utilization system is in the energy storage mode, which includes the following three states: State 1: When the hydrogen amount HS in the hydrogen storage tank is less than the first hydrogen storage threshold, the grid power Grid supplies the sum of the user-side power demand Load and the power consumption EL of the water electrolysis hydrogen production module during the off-peak period; State 2: when the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is greater than the third current charge rate threshold, the grid power Grid supplies the user-side power demand Load during the off-peak period; State 3: When the hydrogen amount HS of the hydrogen storage tank is greater than the first hydrogen storage threshold and the current charge rate SOC of the battery is less than the third current charge rate threshold, the grid power Grid supplies the sum of the user-side power demand Load and the battery power BT during the off-peak period.

4. The state machine-based integrated energy system control method according to claim 1, characterized in that: When the power grid is in peak period, the integrated energy utilization system is in energy consumption mode. The energy consumption mode is divided into low energy consumption mode and high energy consumption mode according to the high and low periods of power consumption on the user side. The low energy consumption mode includes the following four states: State 4: When the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging; State 5: When the photovoltaic power generation PV is greater than the user-side load demand Load and the battery current charge rate SOC is less than a first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load and the battery charge BT; State 6: when the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than a second current charge rate threshold, the photovoltaic power generation PV and the battery discharge capacity BT supply the user-side load demand Load; State 7: When the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than a second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging.

5. The state machine-based integrated energy system control method according to claim 1, characterized in that: When the power grid is in peak period, the integrated energy utilization system is in energy consumption mode. The energy consumption mode is divided into low energy consumption mode and high energy consumption mode according to the high and low periods of power consumption on the user side. The high energy consumption mode includes the following 10 states: State 8: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the photovoltaic power generation PV supplies the user-side load demand Load, and the battery stops charging; State 9: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the photovoltaic power generation PV supplies the sum of the user-side load demand Load and the battery charge capacity BT; State 10: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the photovoltaic power generation PV and the battery discharge capacity BT supply the user-side load demand Load; State 11: When the hydrogen amount HS in the hydrogen storage tank is less than the second hydrogen storage threshold, and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than the second current charge rate threshold, the photovoltaic power generation PV and the grid power Grid supply the user-side load demand Load, and the battery stops discharging; State 12: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the fuel cell power generation FC is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the fuel cell power generation FC is supplied to the user-side load demand Load, and the excess power EE can be supplied to the electric heating heat storage; State 13: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the fuel cell power generation FC is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC supplies the sum of the user-side load demand Load and the battery charge capacity BT; State 14: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is greater than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV, and the battery discharge BT; State 15: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is less than the user-side load demand Load, and the battery current charge rate SOC is less than the second current charge rate threshold, the user-side load demand Load is supplied by the fuel cell power generation FC, the photovoltaic power generation PV and the grid power Grid; State 16: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is less than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the battery charge BT; State 17: When the hydrogen amount HS in the hydrogen storage tank is greater than the second hydrogen storage threshold, and the sum of the fuel cell power generation FC and the photovoltaic power generation PV is greater than the user-side load demand Load, and the battery current charge rate SOC is greater than the first current charge rate threshold, the fuel cell power generation FC and the photovoltaic power generation PV supply the user-side load demand Load and the excess power EE.

6. The state machine-based integrated energy system control method according to claim 3, characterized in that: The first hydrogen storage threshold is 90% of the total hydrogen storage capacity of the hydrogen storage tank; the third current charge rate threshold is 70% of the total charge rate of the battery.

7. The state machine-based integrated energy system control method according to claim 4, characterized in that: The first hydrogen storage threshold is 90% of the total hydrogen storage capacity of the hydrogen storage tank, and the first current charge rate threshold is 99% of the total charge rate of the battery.

8. The state machine-based integrated energy system control method according to claim 4, characterized in that: The second hydrogen storage threshold is 10% of the total hydrogen storage capacity of the hydrogen storage tank, and the second current charge rate threshold is 10% of the total charge rate of the battery.

9. The state machine-based integrated energy system control method according to claim 1, characterized in that: The battery SOC is calculated as follows: in Indicates the remaining battery power. Indicates the total battery capacity, using the initial state and discharge The integration over time estimates the battery .

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