Control method, device and control equipment of clean energy hydrogen production system

Abstract

The disclosed embodiments provide a control method, device and control equipment for a clean energy hydrogen production system. The clean energy hydrogen production system includes a clean power generation system, a power transmission and transformation system and an electrolyzer, wherein the electrolyzer includes at least one first type electrolyzer and at least one second type electrolyzer, and the lower limit of the load variation range of the first type electrolyzer is smaller than that of the second type electrolyzer; the control method of the clean energy hydrogen production system includes: determining the output power of the clean power generation system; determining the operating status of each of the first type electrolyzers and each of the second type electrolyzers according to the output power, the power characteristics of the first type electrolyzer and the rated power of the second type electrolyzer, so as to maximize the utilization of the output power.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electric energy hydrogen production, and in particular to a control method, device and control equipment for a clean energy hydrogen production system. Background Art

[0002] The related technology proposes a scheme to produce hydrogen using clean energy such as photovoltaic power generation and wind turbine power generation. For example, a document proposed a photovoltaic hydrogen production system model that takes into account the influence of multiple variable factors. However, the aforementioned photovoltaic hydrogen production system model does not take into account the impact of clean energy hydrogen production, such as changes in light intensity and wind power on the power output, and then does not take into account the impact on the energy balance of the system. To solve this problem, subsequent documents proposed to establish a photovoltaic hydrogen production direct coupling system model, and proposed a dynamic adjustment optimization strategy to address the problem of poor system flexibility under the condition of photovoltaic power generation power fluctuations, and then achieve the optimal absorption of the photovoltaic system. However, the system efficiency of the aforementioned scheme is low and is not suitable for large-scale application. Summary of the invention

[0003] In order to solve the above technical problems, the embodiments of the present disclosure provide a control method, device and control equipment for a clean energy hydrogen production system.

[0004] In a first aspect, an embodiment of the present disclosure provides a control method for a clean energy hydrogen production system, wherein the clean energy hydrogen production system includes a clean power generation system, a power transmission and transformation system, and an electrolyzer, wherein the electrolyzer includes at least one first type electrolyzer and at least one second type electrolyzer, and the lower limit of the load variation range of the first type electrolyzer is smaller than that of the second type electrolyzer; the control method includes:

[0005] Determining the output power of the clean power generation system;

[0006] According to the output power, the power characteristics of the first type electrolytic cell and the rated power of the second type electrolytic cell, the operating status of each of the first type electrolytic cells and each of the second type electrolytic cells is determined to maximize the utilization of the output power.

[0007] Optionally, determining the operating state of each of the first-type electrolyzers and each of the second-type electrolyzers according to the output power, the power characteristics of the first-type electrolyzers, and the rated power of the second-type electrolyzers includes:

[0008] When the output power is greater than or equal to the rated power of the second type electrolytic cell, the number M of the second type electrolytic cells in operation is determined according to the output power and the rated power of the second type electrolytic cell;

[0009] Calculating a first surplus power according to the output power and the rated powers of the M second-type electrolyzers;

[0010] determining the operating state of each of the first-type electrolytic cells according to the first residual power and the power characteristics of the first-type electrolytic cells; or,

[0011] When the output power is less than the rated power of the second-type electrolytic cell, the operating state of each of the first-type electrolytic cells is determined according to the output power and the power characteristics of the first-type electrolytic cell.

[0012] Optionally, determining the operating state of each of the first-type electrolyzers according to the first residual power and the power characteristics of the first-type electrolyzers includes:

[0013] In the case where the first surplus power is greater than the rated power of the first type electrolytic cell, determining the number N of first type electrolytic cells operating at the rated power according to the first surplus power and the rated power of the first type electrolytic cell;

[0014] Calculating a second surplus power according to the first surplus power and the rated powers of N electrolyzers of the first type;

[0015] When the second surplus power is greater than or equal to the minimum starting power of the first type electrolyzer, controlling one of the first type electrolyzers to operate according to the second surplus power; or,

[0016] When the second surplus power is less than the minimum starting power of the first type electrolytic cell, all the first type electrolytic cells are controlled to be in a standby state.

[0017] Optionally, the clean power generation system includes a photovoltaic power generation system;

[0018] The determining the output power of the clean power generation system comprises: obtaining the output voltage and output current of the photovoltaic array in the photovoltaic power generation system;

[0019] The output power is determined according to the output voltage and the output current.

[0020] Optionally, the power transmission and transformation system includes a first DC / DC circuit whose input side is connected to an output side of the photovoltaic array; after determining the output power according to the output voltage and the output current, the method further includes:

[0021] Using a maximum power tracking control algorithm, determining first duty cycle control data according to the output voltage and the output current;

[0022] The first duty cycle control data is used to control the first DC / DC circuit.

[0023] Optionally, the clean energy hydrogen production system further includes an energy storage circuit connected in parallel with the output side of the first DC / DC circuit on the terminal side; the method further includes:

[0024] The operating state of the energy storage circuit is determined according to the reference voltage, the measured voltage and the measured current at the output end of the first DC / DC circuit, and the operating state is one of an energy storage operating state, a discharge operating state or an off-grid state.

[0025] Optionally, the power transmission and transformation system further includes a DC / AC circuit whose input side is connected to an output side of the first DC / DC circuit; and the control method further includes:

[0026] The second duty cycle is determined by adopting a virtual synchronous generator strategy to connect a voltage control outer loop and a current control inner loop in series;

[0027] The DC / AC circuit is controlled based on the second duty cycle.

[0028] Optionally, the power transmission and transformation system further includes a second DC / DC circuit whose output side is respectively connected to the corresponding first type electrolytic cell or second type electrolytic cell; and the control method further includes:

[0029] Determine the cell end reference current according to the operating power of each of the first type electrolytic cells or the second type electrolytic cells and the cell end set voltage;

[0030] Determining a third duty cycle based on the slot end reference current and the slot end measured current;

[0031] The second DC / DC circuit is controlled based on the third duty ratio.

[0032] In a second aspect, an embodiment of the present disclosure provides a control device for a clean energy hydrogen production system, wherein the clean energy hydrogen production system includes a clean power generation system, a power transmission and transformation system, and an electrolyzer, wherein the electrolyzer includes at least one first type electrolyzer and at least one second type electrolyzer, wherein the lower limit of the load variation range of the first type electrolyzer is smaller than that of the second type electrolyzer, and the rated power of the first type electrolyzer is smaller than that of the second type electrolyzer; the control device includes:

[0033] A power generation side output power determination unit, used to determine the output power of the clean power generation system;

[0034] The electrolytic cell control unit is used to determine the operating status of each of the first-type electrolytic cells and each of the second-type electrolytic cells according to the output power, the power characteristics of the first-type electrolytic cells and the rated power of the second-type electrolytic cells.

[0035] In a third aspect, an embodiment of the present disclosure provides a control device, comprising a processor and a memory, wherein the memory is used to store a computer program; when the computer program is loaded by the processor, the processor executes a control method for a clean energy hydrogen production system as described in any of the preceding items.

[0036] By adopting the scheme provided by the embodiment of the present disclosure, the operating status of each first-type electrolyzer and each second-type electrolyzer is determined according to the output power, the power characteristics of the first-type electrolyzer and the rated power of the second-type electrolyzer. The number of started-up first-type electrolyzers, the number of operating second-type electrolyzers, and the operating power of each operating first-type electrolyzer and the operating power of the second-type electrolyzer are reasonably set, so as to make full use of the electric energy generated by the clean power generation system as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work, including:

[0039] Figure 1 is a structural schematic diagram of a clean energy hydrogen production system provided by an embodiment of the present disclosure;

[0040] Figure 2 is a flow chart of a control method for a clean energy hydrogen production system provided by an embodiment of the present disclosure;

[0041] Figure 3 is a control principle diagram of the energy storage system in an embodiment of the present disclosure;

[0042] Figure 4 is a flow chart of the VSG control strategy provided by an embodiment of the present disclosure;

[0043] Figure 5 is a schematic diagram of the control principle for determining the third duty cycle;

[0044] Figure 6 is a structural schematic diagram of a control device for a clean energy hydrogen production system provided by an embodiment of the present disclosure;

[0045] Figure 7 It is a structural diagram of a control device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0047] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in this disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0048] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0049] In order to solve the problem that the clean energy hydrogen production system proposed in the related technology adopts a dynamic adjustment optimization strategy to achieve the optimal absorption of the photovoltaic system, but the system efficiency of the aforementioned solution is low and is not suitable for large-scale application, the embodiment of the present disclosure provides a control method for a clean energy hydrogen production system. This control method is based on a clean energy hydrogen production system with a specific architecture for control, so as to dynamically adjust the operation of the electrolyzer when the clean energy power generation power is not stable, reduce energy waste and enhance the adaptability of the system.

[0050] Before analyzing the control method of the clean energy hydrogen production system provided by the embodiment of the present disclosure, a simple analysis is first made of the clean energy hydrogen production system provided by the embodiment of the present disclosure. The clean energy hydrogen production system provided by the embodiment of the present disclosure includes a clean power generation system, a power transmission and transformation system, and an electrolyzer.

[0051] The clean power generation system may be a photovoltaic power generation system, a wind power generation system, or a photovoltaic-wind hybrid power generation system, which is used to convert clean energy such as solar energy, wind energy, etc. into photoelectric energy to generate and output electrical energy.

[0052] The power transmission and transformation system is used to step up and down the voltage of the electric energy generated by the clean power generation system to reduce the loss of the transmission line and to decouple the clean power generation system and the hydrogen production system as much as possible to ensure the stability and reliability of the entire system during operation. In specific implementation, the power transmission and transformation system can be an AC power transmission and transformation system or a DC power transmission and transformation system.

[0053] The AC power transmission and transformation system first performs DC boost processing on the electric energy generated by the clean power generation system to increase the voltage to the first DC bus voltage, and then performs DC-AC conversion to convert DC power into AC power. After converting DC power into AC power, the electric energy is transmitted to the power consumption side via the AC transmission line, and then AC-DC conversion is performed on the power consumption side to convert AC power into DC power. After that, the DC power is transmitted to the DC-DC circuit at the electrolyzer end through the DC bus, and the DC power is converted into DC power that meets the working voltage of the electrolyzer using the DC-DC circuit at the electrolyzer end.

[0054] The DC power transmission and transformation system is a power transmission system that does not perform DC-AC and AC-DC conversion on electric energy, but only performs DC-DC conversion. For example, it first performs DC boost processing on the electric energy generated by the clean power generation system, raising the voltage to the first DC bus voltage, and then transmits the electric energy to the power consumption side using the DC transmission line, and then uses the DC-DC circuit on the power consumption side to perform voltage conversion, and transmits the converted voltage to the DC-DC current at the electrolyzer end, and uses the DC-DC circuit at the electrolyzer end to convert the DC power into DC power that meets the working voltage of the electrolyzer.

[0055] The electrolyzer is a device that uses direct current electricity to produce hydrogen. In the embodiment of the present disclosure, the electrolyzer includes at least one first-type electrolyzer and at least one second-type electrolyzer. In a specific implementation, the number of the first-type electrolyzer and the second-type electrolyzer can be determined according to the power generation of the clean power generation system under normal conditions, so as to make full use of the power generated by the clean power generation system as much as possible.

[0056] In the disclosed embodiment, the lower limit of the load variation interval of the first type electrolyzer is smaller than that of the second type electrolyzer to ensure that the first type electrolyzer can be started at a relatively small input power. The rated power of the second type electrolyzer is greater than that of the first type electrolyzer, and the hydrogen production efficiency of the second type electrolyzer at its rated power is higher than that of the first type electrolyzer. In a specific implementation, the second type electrolyzer may be an alkaline electrolyzer, and the first type electrolyzer may be an ion exchange membrane (Proton Exchange Membrane, PEM) electrolyzer. In a specific implementation, ideally, the rated power of all the first type electrolyzers is equal to or slightly greater than the rated power of one second type electrolyzer. In addition, the first type electrolyzer is preferably an electrolyzer that takes less time to start up and can operate at low temperatures.

[0057] In some embodiments, the first type of electrolyzer is a PEM electrolyzer. The PEM electrolyzer voltage model consists of a reversible voltage V rev , activation overvoltage V act , mass transfer overvoltage V mass and ohmic overvoltage V ohm It consists of four parts. V=V rev +V act +V mass +V ohm , V is the set voltage at the cell end of the PEM electrolyzer.

[0058] Reversible voltage V rev The equation is: Where, E0 is the standard electromotive force; R is the ideal gas constant,; F is the Faraday constant, 96485C / mol; is the hydrogen partial pressure; is the partial pressure of oxygen; is the water activity between the anode and the electrolyte, which is 1; ΔG f is the Gibbs free energy change of the electrochemical reaction process.

[0059] Activation overvoltage V act The equation is Where: α is the transfer coefficient; i is the current density; i0 is the exchange current density.

[0060] Mass transfer overvoltage V mass The equation is Among them C R is the concentration of reactants; C P is the product concentration.

[0061] Ohmic overvoltage V ohm The equation is: Where: R ohm is the membrane resistance; σ m is the conductivity of the membrane, which is expressed as: λ m is the water content of the membrane.

[0062] The efficiency calculation formula of PEM electrolyzer is: Where E0 is the standard electromotive force; V Pem is the actual voltage of the electrolytic cell.

[0063] Figure 1 Schematic diagram of the structure of a clean energy hydrogen production system provided by an embodiment of the present disclosure. Figure 1As shown, the clean power generation system in the clean energy hydrogen production system provided in this embodiment is a photovoltaic power generation system, which uses a photovoltaic array to convert solar energy into light energy. In order to be able to transmit the electric energy generated by multiple photovoltaic power generation systems to the power consumption end (that is, the electrolyzer end), the power transmission and transformation system includes a first DC-DC circuit and a DC-AC circuit configured for each independent photovoltaic array to boost the low-voltage electric energy output by the photovoltaic array and connect it to the AC transmission network. In addition, the power transmission and transformation system also includes an AC-DC circuit configured for the first type of electrolyzer and the second type of electrolyzer, respectively, and a DC-DC circuit configured for each electrolyzer. In a specific implementation, the input side of the DC-DC circuit configured for each electrolyzer is connected to the output side of the corresponding AC-DC circuit. After AC-DC conversion and DC conversion, the current is rectified to meet the working voltage of the corresponding type of electrolyzer.

[0064] like Figure 1 As shown, in the embodiment of the present disclosure, in order to ensure the stability of the bus voltage on the output side of the first DC-DC circuit, the clean power generation system also includes an energy storage system, specifically a supercapacitor, and a DC-DC circuit for realizing charging and discharging of the energy storage system.

[0065] The following is an analysis of the control method of the clean energy hydrogen production system provided in the embodiment of the present disclosure. Figure 2 : is a flow chart of the control method of the clean energy hydrogen production system provided by the embodiment of the present disclosure. Figure 2 As shown, the control method of the clean energy hydrogen production system provided in the embodiment of the present disclosure includes S110-S120.

[0066] S110: Determine the output power of the clean power generation system.

[0067] In some specific implementations, determining the output power of the clean power generation system may be performed by obtaining the output voltage and output current of the clean power generation system, and calculating the output power using the output current and output voltage. Figure 1 In the case of multiple photovoltaic arrays, the output power of each photovoltaic array can be obtained by measuring the output voltage and output current of each photovoltaic array respectively, and the output power of each photovoltaic array is added to obtain the output power of the clean power generation system.

[0068] In other applications, the output power of the clean power generation system can also be determined by obtaining the current and voltage at a location in the entire DC power transmission and transformation system before energy diversion is achieved. Figure 1 The clean energy hydrogen production system shown can measure the current and voltage in the AC transmission line to determine the output power of the clean power generation system. Figure 1The clean energy hydrogen production system shown can measure the output current and output voltage of each first DC-DC conversion circuit, determine the input power of each DC-AC conversion circuit, and add the aforementioned input powers to obtain the output power of the clean power generation system.

[0069] S120: Determine the operating status of each first-type electrolytic cell and each second-type electrolytic cell according to the output power, the power characteristics of the first-type electrolytic cell and the rated power of the second-type electrolytic cell.

[0070] In the disclosed embodiment, the goal to be achieved is to reasonably adjust the working state of each electrolytic cell so that the working power of each electrolytic cell matches the output power of the clean power generation system as much as possible, thereby fully utilizing the electric energy generated by the clean power generation system.

[0071] In accordance with the above-mentioned objectives, the operating status of each type-one electrolyzer and each type-two electrolyzer is determined according to the output power, the power characteristics of the type-one electrolyzer and the rated power of the type-two electrolyzer. This is achieved by reasonably setting the number of type-one electrolyzers to be started, the number of type-two electrolyzers in operation, and the operating power of each type-one electrolyzer in operation and the operating power of each type-two electrolyzer in operation, so as to make the best possible use of the electric energy generated by the clean power generation system.

[0072] In the specific implementation, considering that after passing through the power transmission and transformation system, the electric energy will generate loss due to transmission and transformation in the power transmission and transformation system, in the specific implementation, after determining the output power of the clean power generation system, the above-mentioned output power and a pre-set grid efficiency coefficient can be used to roughly determine the actual electric energy power used for hydrogen production by electrolysis in the electrolyzer.

[0073] In a specific implementation, the aforementioned S120 may include S121 - S122 .

[0074] S121: Determine whether the output power is greater than or equal to the rated power of the second type electrolytic cell; if so, execute S122; if not, execute S123.

[0075] S122: Determine the number M of operating second-type electrolytic cells according to the output power and the rated power of the second-type electrolytic cells.

[0076] Judging whether the output power is greater than or equal to the rated power of the second type electrolyzer is to judge whether the output power of the clean power generation system can support at least one second type electrolyzer to operate at the rated power. If the output power is greater than or equal to the rated power of the second type electrolyzer, it is determined that the output power can at least support at least one second type electrolyzer to operate at its rated power, and at this time, the second type electrolyzer should be kept in operation as much as possible. At this time, it can be judged how many second type electrolyzers can be supported to operate according to the output power and the rated power of the second type electrolyzer.

[0077] In a specific implementation, the output power can be divided by the rated power of the second type electrolyzer to obtain the calculated data, and the aforementioned calculated data can be rounded down to determine the number of operating second type electrolyzers M. Combined with the above description, M is a positive integer, and the maximum value of M is the number of second type electrolyzers in the clean energy hydrogen production system.

[0078] S123: Calculate the first surplus power according to the output power and the rated power of the M second-type electrolytic cells.

[0079] S124: Determine the operating status of each first-type electrolytic cell according to the first residual power and the power characteristics of the first-type electrolytic cell.

[0080] In practical applications, after determining that the second type electrolyzer can support operation at its rated power based on the output power, there may be surplus power. In order to make the most of the surplus power, the required power of M second type electrolyzers when operating at the rated power is calculated, and the required power is subtracted from the output power to obtain the first surplus power.

[0081] After the first surplus power is obtained, the first surplus power and the power characteristics of the first type electrolytic cells may be used to determine the operating status of each first type electrolytic cell.

[0082] Here, the power characteristics of the first type electrolytic cell include the rated power of the first type electrolytic cell and the minimum starting power of the first type electrolytic cell.

[0083] In a specific implementation, S124 may specifically include S1241-S1247.

[0084] S1241: Determine whether the first residual power is greater than the rated power of the first type electrolytic cell; if so, execute S1242; if not, execute S1247.

[0085] S1242: Determine the number N of operating first-type electrolytic cells operating at the rated power according to the first residual power and the rated power of the first-type electrolytic cells.

[0086] S1243: Calculate the second surplus power according to the first surplus power and the rated powers of the N first-type electrolytic cells.

[0087] In a specific implementation, the required power of N first-type electrolyzers when operating at rated power can be calculated, and the required power can be subtracted from the first residual power to obtain the second residual power.

[0088] S1244: Determine whether the second residual power is greater than the minimum starting power of the first type electrolytic cell; if so, execute S1245; if not, execute S1246.

[0089] S1245: Control a first type electrolytic cell to operate according to the second residual power.

[0090] S1246: Control the other first-type electrolytic cells except the N first-type electrolytic cells to be in a standby state.

[0091] S1247: Control all first type electrolytic cells to be in standby state.

[0092] If the second residual power is greater than or equal to the minimum starting power of the first type electrolyzer, it is determined that one first type electrolyzer can be started and operated according to the second residual power, so one first type electrolyzer can be controlled to operate according to the second residual power. If the second residual power is less than the minimum starting power of the first type electrolyzer, it is determined that the second residual power cannot support the start-up of the first type electrolyzer, and at this time, the remaining electrolyzers can be placed in a standby state.

[0093] S125: Determine the operating status of each first-type electrolytic cell according to the output power and the power characteristics of the first-type electrolytic cell.

[0094] As analyzed above, if the output power is less than the rated power of the second type electrolyzer, it is determined that it is impossible to keep one second type electrolyzer running at the rated power. At this time, only the output power needs to be considered to ensure the operation of the first type electrolyzer. In the specific implementation, the method for determining the operating status of each first type electrolyzer based on the output power and the power characteristics of the first type electrolyzer is the same as the above S1241-S1246, which will not be repeated here. For details, please refer to the above analysis.

[0095] By adopting the control method of the clean energy hydrogen production system provided by the embodiment of the present disclosure, the operating status of each type one electrolyzer and the type two electrolyzer is determined according to the output power of the clean power generation system, the power characteristics of the type one electrolyzer and the rated power of the type two electrolyzer, so as to maximize the utilization of the output power as much as possible.

[0096] As analyzed above, the clean power generation system can be a photovoltaic power generation system. Among them, I sc Short circuit current; T Photovoltaic cell operating temperature; T ref Reference temperature, the value is 298.15K; G irradiance; G ref Reference irradiance, usually 1000W / m2; α is the temperature coefficient of the photovoltaic cell. The reverse saturation current of the diode in the photovoltaic power generation system Where I0 is saturation current, A; R s Photovoltaic cell series resistance, Ω; n reverse saturation current index; q the charge of the electron, 1.602×10-19C; k Boltzmann constant. Correspondingly, the output current of the photovoltaic power generation system R sh is the parallel resistance of the photovoltaic cell.

[0097] The aforementioned S110 determines the output power of the clean power generation system by obtaining the output voltage and output current of the photovoltaic array in the photovoltaic power generation system, and determining the output power according to the output voltage and output current.

[0098] like Figure 1 As shown, in some embodiments, the power transmission and transformation system includes a first DC / DC circuit whose input side is connected to the output side of the photovoltaic array. The working state of the first DC / DC circuit will affect the output power of the photovoltaic array (specifically, the output voltage and output current of the photovoltaic array). In order to maximize the output power of the photovoltaic array as much as possible, after obtaining the output voltage and output current of the photovoltaic array, the following S210-S220 can also be performed.

[0099] S210: adopting a maximum power tracking control algorithm to determine first duty cycle control data according to the output voltage and the output current.

[0100] S220: Control the first DC / DC circuit using the first duty cycle control data.

[0101] The aforementioned first duty cycle data is data for controlling the operating characteristics of the converter in the first DC / DC circuit, specifically data for controlling the off state of the IGBT in the converter of the first DC / DC circuit.

[0102] In a specific implementation, a maximum power tracking control algorithm such as the conductance increment method, the open circuit voltage method, the short circuit power method or the disturbance observation method can be used to determine the first duty cycle control data. Among them, the conductance increment method performs better and is more accurate when the light changes rapidly; the open circuit voltage method and the short circuit current method do not require disturbances to the current and voltage; the disturbance observation method uses a method of constantly approaching the maximum power point, which is simple and easy to implement, has low requirements on the system hardware, and can effectively track the maximum power of the photovoltaic power generation system as the external environment changes.

[0103] In a specific application, an adaptive step-size observation type maximum power tracking control algorithm can be used to adaptively adjust the disturbance step size and step size by observing and comparing the changes in power and voltage, thereby effectively reaching the maximum power point of the photovoltaic array. Specifically, firstly, the degree of power change is detected to determine the degree of deviation of the current working point relative to the maximum power point; that is, the current output power is calculated according to the output voltage and output current of the photovoltaic array, and the power change rate is calculated using the current output power and the previous output power, and the voltage change rate is calculated using the current output voltage and the previous output voltage. The disturbance step size and compensation are adjusted according to the current output voltage change rate and the previous output change rate, and the first duty cycle control data is determined using the disturbance step size and compensation. When the power change is more significant, the disturbance step size and step size are gradually increased to quickly approach the maximum power point. On the contrary, when the power change is small, the disturbance step size and step size are gradually reduced to ensure the stability of the position system and avoid oscillation during the search process.

[0104] like Figure 1 As shown, the clean energy hydrogen production system in the disclosed embodiment also includes an energy storage circuit connected in parallel with the output side of the first DC / DC circuit. The main function of the energy storage circuit connected in parallel with the output side of the first DC / DC circuit is to ensure the voltage on the output side of the first DC / DC circuit, to avoid excessive voltage disturbance on the output side causing instability in the subsequent substation system, and its main function is not to provide and store electrical energy to the power grid. In this case, it is also necessary to reasonably control the state of the energy storage circuit to meet the aforementioned requirements. In a specific implementation, the operating state of the energy storage circuit can be determined based on the reference voltage, measured voltage and measured current at the output end of the first DC / DC circuit. The aforementioned operating states are energy storage operating state, discharge operating state or off-grid state. The energy storage operating state is a state in which electrical energy is stored in the energy storage system, the discharge operating state is a state in which the energy storage system discharges outward, and the off-grid state is a state in which the voltage of the first DC / DC circuit is stable at a reference voltage and a reference current.

[0105] In the embodiment of the present disclosure, the energy storage system uses a supercapacitor, which can effectively suppress the instantaneous fluctuation of the output DC voltage of the clean power generation system by quickly adjusting the charge state, ensuring that the DC bus voltage remains within an acceptable range and improving the system stability. Among them I sc is the supercapacitor working current; R sc is the equivalent resistance of the supercapacitor; C is the equivalent capacitance of the supercapacitor.

[0106] Figure 3 is a control principle diagram of the energy storage system in the embodiment of the present disclosure. Figure 3As shown, the energy storage system uses supercapacitors, which are connected to the DC bus through a bidirectional DC-DC converter. Because the role of the supercapacitor is to keep the DC bus voltage constant when the entire system is working, the DC-DC converter adopts constant voltage control, which adopts a dual closed-loop control strategy (voltage outer loop plus current inner loop control strategy). dcref is the reference voltage at the output end of the first DC / DC circuit, I scref Based on the aforementioned reference voltage and the measured voltage U dc After comparison, PI control is performed to determine the reference value of the supercapacitor inductor power. scref After that, by comparing the above current reference value I scref and the actual value of the supercapacitor inductor current, and after adopting PI control, the switch control signal D used to control switches S1 and S2 can be obtained sc1 and D sc1 , through D sc1 and D sc1 Control the energy storage circuit to be in the energy storage operation state, the discharge operation state or the off-grid state.

[0107] like Figure 1 As shown, in some embodiments, the power transmission and transformation system includes a DC / AC circuit whose input side is connected to the output side of the first DC / DC circuit. The aforementioned control method may also include the following S310-S320.

[0108] S310: Determine the second duty cycle by adopting a method of connecting a virtual synchronous generator in series with an outer loop of voltage control and an inner loop of current control.

[0109] S320: Control the DC / AC circuit based on the second duty cycle.

[0110] In the specific implementation, in the embodiment of the present disclosure, the strategy of connecting the virtual synchronous generator in series with the outer loop of voltage control and the inner loop of current control is called the VSG control strategy. The VSG control strategy consists of an active loop, a reactive loop, a virtual impedance calculation, and a voltage-current double closed loop. Figure 4 It is a flow chart of the VSG control strategy provided by an embodiment of the present disclosure.

[0111] In practical applications, the VSG control strategy requires the introduction of the rotor motion state equation Where T m is the mechanical torque; T e is the electromagnetic torque; P m is the mechanical power; P e is the electromagnetic power; ω is the rotor angular frequency; δ is the voltage phase; ω n is the rated angular frequency of the power grid; J is the moment of inertia; D is the damping coefficient.

[0112] To achieve output reactive power control, the Simulate the excitation voltage regulation function of synchronous generator, Q e is the reactive power output value; Q ref is the reactive power setting value; U n is the rated peak value of the terminal voltage; U0 is the actual peak value of the terminal voltage; E is the peak potential of the bridge arm of the grid-side inverter; K q is the reactive power droop coefficient; K is the reactive power regulation coefficient.

[0113] By using virtual synchronous generator control on the power grid side converter, inertia and frequency support can be provided to the power grid, thereby improving grid stability and reducing power fluctuations. In addition, virtual synchronous generator technology enables the converter in the DC / AC circuit to quickly respond to changes in grid demand, improving the operating efficiency and reliability of the power generation side system.

[0114] like Figure 1 As shown, the power transmission and transformation system further includes a second DC / DC circuit whose output side is respectively connected to the corresponding first type electrolytic cell or second type electrolytic cell. The corresponding control method may also include the following S410-S430.

[0115] S410: Determine a cell end reference current according to the operating power of each first type electrolytic cell or second type electrolytic cell and a cell end set voltage.

[0116] S420: Determine a third duty cycle based on the slot end reference current and the slot end measured current.

[0117] S430: Control the second DC / DC circuit based on the third duty cycle.

[0118] Figure 5 This is a schematic diagram of the control principle for determining the third duty cycle. Figure 5 As shown, in the example of the present disclosure, firstly, according to the operating power P of the electrolytic cell determined in the above text elref and the slot end setting voltage U el Determine the slot end set current I elref , then use I elref and the measured current I el After making the difference, the PWM generator generates a third duty cycle through PI control.

[0119] In addition to providing the aforementioned control method for the clean energy hydrogen production system, the embodiment of the present disclosure also provides a control device for the clean energy hydrogen production system. Figure 6 Schematic diagram of the structure of the control device of the clean energy hydrogen production system provided by the embodiment of the present disclosure. Figure 6 As shown, the control device 600 of the clean energy hydrogen production system includes a power generation side output power determination unit 601 and an electrolyzer control unit 602.

[0120] The power generation side output power determination unit 601 is used to determine the output power of the clean power generation system; the electrolytic cell control unit 602 is used to determine the operating status of each first type electrolytic cell and each second type electrolytic cell according to the output power, the power characteristics of the first type electrolytic cell and the rated power of the second type electrolytic cell.

[0121] In some embodiments, when the output power is greater than or equal to the rated power of the second type electrolyzer, the electrolyzer control unit 602 determines the number of operating second type electrolyzers M according to the operating power and the rated power of the second type electrolyzer; then, the first residual power is calculated according to the output power and the rated power of the M second type electrolyzers; finally, the operating state of each first type electrolyzer is determined according to the first residual power and the power characteristics of the first type electrolyzer. Alternatively, when the output power is less than the rated power of the second type electrolyzer, the electrolyzer control unit 602 determines the operating state of each first type electrolyzer according to the output power and the power characteristics of the first type electrolyzer.

[0122] In some embodiments, when the first residual power is greater than the rated power of the first type electrolyzer, the electrolyzer control unit 602 determines the number N of operating first type electrolyzers operating at the rated power based on the first residual power and the rated power of the first type electrolyzer; then calculates the second residual power based on the first residual power and the rated power of the N first type electrolyzers; finally, when the second residual power is greater than or equal to the minimum starting power of the first type electrolyzer, controls one first type electrolyzer to operate at the second residual power; or, when the second residual power is less than the minimum starting power of the first type electrolyzer, the electrolyzer control unit 602 controls all the first type electrolyzers to be in standby mode.

[0123] In some embodiments, the clean power generation system includes a photovoltaic power generation system; the power generation side output power determination unit 601 obtains the output voltage and output current of the photovoltaic array in the photovoltaic power generation system; and determines the output power according to the output voltage and output current.

[0124] In some embodiments, the power transmission and transformation system includes a first DC / DC circuit whose input side is connected to the output side of a photovoltaic array; the control device also includes a transformation control unit, which adopts a maximum power tracking control algorithm to determine first duty cycle control data based on the output voltage and the output current; and the first duty cycle control data is used to control the first DC / DC circuit.

[0125] In some embodiments, the clean energy hydrogen production system also includes an energy storage circuit connected in parallel with the output side of the first DC / DC circuit; the power transformation control unit determines the operating state of the energy storage circuit based on the reference voltage, measured voltage and measured current at the output end of the first DC / DC circuit, and the operating state is one of the energy storage operating state, the discharge operating state or the off-grid state.

[0126] In some embodiments, the power transmission and transformation system also includes a DC / AC circuit connected on the input side to the output side of the first DC / DC circuit; the power transformation control unit determines the second duty cycle by using a virtual synchronous generator strategy to connect a voltage control outer loop and a current control inner loop in series; and controls the DC / AC circuit based on the second duty cycle.

[0127] In some embodiments, the power transmission and transformation system also includes a second DC / DC circuit whose output side is respectively connected to the corresponding first type electrolytic cell or second type electrolytic cell; the transformation control unit determines the slot end reference current according to the operating power of each first type electrolytic cell or second type electrolytic cell and the slot end set voltage; then, determines the third duty cycle based on the slot end reference current and the slot end measured current, and finally controls the second DC / DC circuit based on the third duty cycle.

[0128] In addition to providing the aforementioned control method and apparatus for the clean energy hydrogen production system, the embodiments of the present disclosure also provide a control device. Figure 7 Schematic diagram of the structure of the control device provided by the embodiment of the present disclosure. Figure 7 , which shows a structural schematic diagram of a control device 700 suitable for implementing the embodiments of the present disclosure. Figure 7 The control device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0129] like Figure 7 As shown, the control device 700 may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory ROM 702 or a program loaded from a storage device 708 to a random access memory RAM 703. In the RAM 703, various programs and data required for the operation of the control device 700 are also stored. The processing device 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output I / O interface 705 is also connected to the bus 704.

[0130] Typically, the following devices may be connected to the I / O interface 705: input devices including, for example, a touch screen, a touch pad, a camera, a microphone, an accelerometer, a gyroscope, etc.; output devices 707 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 708 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 709. The communication devices 709 may allow the control device 700 to communicate with other devices wirelessly or by wire to exchange data. Although Figure 4 The control device 700 is shown with various devices, but it should be understood that it is not required to implement or have all the devices shown. More or fewer devices may be implemented or have instead.

[0131] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a non-transitory computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device 709, or installed from a storage device 708, or installed from a ROM 702. When the computer program is executed by the processing device 701, the above-mentioned functions defined in the method of the embodiment of the present disclosure are executed.

[0132] It should be noted that the computer-readable medium disclosed above may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0133] In some embodiments, the client and the server may communicate using any currently known or future developed network protocol such as HTTP (HyperText Transfer Protocol), and may be interconnected with any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network ("LAN"), a wide area network ("WAN"), an internet (e.g., the Internet), and a peer-to-peer network (e.g., an ad hoc peer-to-peer network), as well as any currently known or future developed network.

[0134] The computer-readable medium may be included in the control device, or may exist independently without being assembled into the control device.

[0135] The computer-readable medium carries one or more programs. When the one or more programs are executed by the control device, the control device: determines the output power of the clean power generation system; determines the operating status of each of the first-type electrolyzers and each of the second-type electrolyzers according to the output power, the power characteristics of the first-type electrolyzers and the rated power of the second-type electrolyzers, so as to maximize the utilization of the output power.

[0136] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages ​​or a combination thereof, including, but not limited to, object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the tester's computer, partially on the tester's computer, as a separate software package, partially on the tester's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the tester's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0137] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated system based on hardware that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0138] The units involved in the embodiments described in the present disclosure may be implemented by software or hardware, wherein the name of a unit does not, in some cases, limit the unit itself.

[0139] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0140] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection according to one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0141] The embodiments of the present disclosure also provide a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the method of any of the above method embodiments can be implemented. The execution method and beneficial effects are similar and will not be repeated here.

[0142] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0143] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a clean energy hydrogen production system, characterized in that: The clean energy hydrogen production system comprises a clean power generation system, a power transmission and transformation system and an electrolyzer, wherein the electrolyzer comprises at least one first-type electrolyzer and at least one second-type electrolyzer, and the lower limit of the load variation range of the first-type electrolyzer is smaller than that of the second-type electrolyzer; the control method comprises: Determining the output power of the clean power generation system; Determining the operating state of each of the first-type electrolytic cells and each of the second-type electrolytic cells according to the output power, the power characteristics of the first-type electrolytic cells, and the rated power of the second-type electrolytic cells, so as to maximize the utilization of the output power; Determining the operating state of each of the first-type electrolytic cells and each of the second-type electrolytic cells according to the output power, the power characteristics of the first-type electrolytic cells, and the rated power of the second-type electrolytic cells, including: When the output power is greater than or equal to the rated power of the second type electrolytic cell, the number M of the second type electrolytic cells in operation is determined according to the output power and the rated power of the second type electrolytic cell; calculating a first surplus power according to the output power and the rated powers of the M second-type electrolyzers; Determining the operating state of each of the first-type electrolytic cells according to the first residual power and the power characteristics of the first-type electrolytic cells; When the output power is less than the rated power of the second-type electrolytic cell, the operating state of each of the first-type electrolytic cells is determined according to the output power and the power characteristics of the first-type electrolytic cell.

2. The control method according to claim 1, characterized in that: Determining the operating state of each of the first-type electrolytic cells according to the first residual power and the power characteristics of the first-type electrolytic cells includes: In the case where the first surplus power is greater than the rated power of the first type electrolytic cell, determining the number N of first type electrolytic cells operating at the rated power according to the first surplus power and the rated power of the first type electrolytic cell; Calculating a second surplus power according to the first surplus power and the rated powers of N electrolyzers of the first type; When the second residual power is greater than or equal to the minimum starting power of the first type electrolyzer, controlling one of the first type electrolyzers to operate according to the second residual power; When the second surplus power is less than the minimum starting power of the first type electrolytic cell, all the first type electrolytic cells are controlled to be in a standby state.

3. The control method according to claim 1 or 2, characterized in that: The clean power generation system includes a photovoltaic power generation system; The determining the output power of the clean power generation system comprises: obtaining the output voltage and output current of the photovoltaic array in the photovoltaic power generation system; The output power is determined according to the output voltage and the output current.

4. The control method according to claim 3, characterized in that: The power transmission and transformation system comprises a first DC / DC circuit connected at an input side to an output side of the photovoltaic array; After determining the output power according to the output voltage and the output current, the method further includes: Using a maximum power tracking control algorithm, determining first duty cycle control data according to the output voltage and the output current; The first duty cycle control data is used to control the first DC / DC circuit.

5. The control method according to claim 4, characterized in that: The clean energy hydrogen production system further includes an energy storage circuit connected in parallel with the output side of the first DC / DC circuit on the terminal side; the method further includes: The operating state of the energy storage circuit is determined according to the reference voltage, the measured voltage and the measured current at the output end of the first DC / DC circuit, and the operating state is one of an energy storage operating state, a discharge operating state or an off-grid state.

6. The control method according to claim 4, characterized in that: The power transmission and transformation system further includes a DC / AC circuit connected at its input side to an output side of the first DC / DC circuit; and the control method further includes: The second duty cycle is determined by adopting a virtual synchronous generator strategy to connect a voltage control outer loop and a current control inner loop in series; The DC / AC circuit is controlled based on the second duty cycle.

7. The control method according to any one of claims 1 or 2, characterized in that: The power transmission and transformation system further includes a second DC / DC circuit connected to the corresponding first type electrolytic cell or second type electrolytic cell at the output side; The control method further comprises: Determine the cell end reference current according to the operating power of each of the first type electrolytic cells or the second type electrolytic cells and the cell end set voltage; Determining a third duty cycle based on the slot end reference current and the slot end measured current; The second DC / DC circuit is controlled based on the third duty ratio.

8. A control device for a clean energy hydrogen production system, characterized in that: The clean energy hydrogen production system comprises a clean power generation system, a power transmission and transformation system and an electrolyzer, wherein the electrolyzer comprises at least one first-type electrolyzer and at least one second-type electrolyzer, the lower limit of the load variation range of the first-type electrolyzer is smaller than that of the second-type electrolyzer, and the rated power of the first-type electrolyzer is smaller than that of the second-type electrolyzer; the control device comprises: A power generation side output power determination unit, used to determine the output power of the clean power generation system; an electrolytic cell control unit, configured to determine the operating state of each of the first-type electrolytic cells and each of the second-type electrolytic cells according to the output power, the power characteristics of the first-type electrolytic cells and the rated power of the second-type electrolytic cells; The electrolytic cell control unit determines the operating state of each of the first-type electrolytic cells and each of the second-type electrolytic cells according to the output power, the power characteristics of the first-type electrolytic cells, and the rated power of the second-type electrolytic cells, including: When the output power is greater than or equal to the rated power of the second type electrolytic cell, the number M of the second type electrolytic cells in operation is determined according to the output power and the rated power of the second type electrolytic cell; Calculating a first surplus power according to the output power and the rated powers of the M second-type electrolyzers; Determining the operating state of each of the first-type electrolytic cells according to the first residual power and the power characteristics of the first-type electrolytic cells; When the output power is less than the rated power of the second-type electrolytic cell, the operating state of each of the first-type electrolytic cells is determined according to the output power and the power characteristics of the first-type electrolytic cell.

9. A control device, characterized in that: comprising a processor and a memory, the memory being used to store a computer program; When the computer program is loaded by the processor, the processor executes the control method of the clean energy hydrogen production system as described in any one of claims 1-7.

Images