A light-hydrogen bilateral cooperative adaptive network construction control method

Abstract

The application discloses a light-hydrogen two-side cooperative self-adaptive network construction control method, which is applied to a light-hydrogen two-side coupling system, the system comprising a photovoltaic power generation unit and an electrolytic hydrogen production unit which are directly connected through an alternating current bus, the photovoltaic power generation unit comprising a photovoltaic panel, a DC / DC module and a DC / AC module, and the electrolytic hydrogen production unit comprising an AC / DC module, a DC / DC module and an electrolytic cell; the method adopts a maximum power point tracking algorithm and voltage threshold control to control the DC / DC module on the photovoltaic side, adopts voltage threshold control to control the DC / DC module on the hydrogen side, and adopts an alternating current droop control method with a phase control mechanism to control the DC / AC module or the AC / DC module, so as to regulate the output frequency, voltage and phase of the corresponding photovoltaic power generation unit or electrolytic hydrogen production unit, and ensure that a dynamic power balance is formed between photovoltaic output and electrolytic load. The application can perform bidirectional regulation and ensure stable operation of the system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cooperative control in the field of new energy, specifically to the field of photovoltaic-hydrogen bilateral cooperative control, and particularly to a photovoltaic-hydrogen bilateral cooperative adaptive network construction control method. BACKGROUND

[0002] With the continuous increase of photovoltaic power generation capacity, the system stability challenge brought by the increasing penetration rate of photovoltaic power generation is increasingly prominent. Unlike the stable output characteristics of traditional thermal power units, photovoltaic power generation has significant intermittency and volatility characteristics. Under the influence of natural factors such as day and night alternation and cloud cover, the output power fluctuates at a minute or even second level, causing the power grid to face severe frequency and voltage regulation pressure.

[0003] As a potential energy carrier in new power systems, hydrogen energy has a high mass energy density of 142 MJ / kg (about 3 times that of gasoline), and through water electrolysis hydrogen production technology, it can realize the bidirectional conversion of "electric energy-hydrogen energy". This characteristic enables the hydrogen energy system to not only smooth photovoltaic power fluctuations, but also convert excess electricity into clean fuel that can be stored for a long time, providing an innovative path for building a multi-time scale energy storage system. However, existing photovoltaic-hydrogen systems mainly use a direct current bus coupling method, which can simplify the system structure, but has the disadvantages of high risk of fault propagation, difficulty in fault isolation, and difficulty in interacting with alternating current power grids. At the same time, the output of the photovoltaic side is directly affected by environmental factors such as light and temperature, and its fluctuations are large. If the dynamic power response of the electrolyzer is mismatched, the unbalanced power can easily cause the system voltage to exceed the limit, which may trigger a chain of faults in the direct current coupling system.

[0004] To solve the above problems, the present application designs a control strategy for a photovoltaic-hydrogen system that includes a photovoltaic power generation unit and an electrolytic hydrogen production unit and is interconnected via an alternating current bus. First, for the AC / DC converters of the photovoltaic power generation unit and the electrolytic hydrogen production unit, a bilateral cooperative network construction control strategy is designed. In the frequency and phase angle control, the intermediate stage direct current voltage deviation of the photovoltaic side and the hydrogen side is added to correct the reference value of the frequency and the phase angle, to realize network construction control, improve the dynamic response of the system, and characterize the power of the photovoltaic-hydrogen system. Second, for the DC / DC converters of the photovoltaic side and the hydrogen side, an adaptive power cooperative control strategy based on the intermediate stage direct current voltage is designed to achieve dynamic power balance for photovoltaic power generation-hydrogen production consumption and avoid voltage collapse caused by system power imbalance. The proposed method can solve the problems of stable network construction and dynamic power balance of the photovoltaic-hydrogen coupling system, and provides a cooperative development technical framework for future high-penetration photovoltaic consumption and green hydrogen production. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provides a photovoltaic-hydrogen bilateral cooperative adaptive network construction control method.

[0006] The application aims to realize the technical scheme of a light-hydrogen bilateral collaborative adaptive network construction control method applied to a light-hydrogen bilateral coupling system, the system comprising a photovoltaic power generation unit, an electrolytic hydrogen production unit and an alternating current bus, wherein the photovoltaic power generation unit and the electrolytic hydrogen production unit are directly connected through the alternating current bus; the photovoltaic power generation unit comprises photovoltaic panels, a DC / DC module and a DC / AC module connected in sequence; the electrolytic hydrogen production unit comprises an AC / DC module, a DC / DC module and an electrolytic cell connected in sequence.

[0007] The method specifically comprises: controlling the DC / DC module on the photovoltaic side by using a maximum power point tracking algorithm and voltage threshold control, so that the DC / DC module operates in a maximum power point tracking mode or a constant power mode or an overvoltage protection mode; controlling the DC / DC module on the hydrogen side by using voltage threshold control, so that the DC / DC module operates in a shutdown protection mode or a constant power mode or a full power mode; controlling the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side by using an alternating current droop control method with a phase control mechanism, so as to regulate the output frequency, voltage and phase of the corresponding photovoltaic power generation unit or electrolytic hydrogen production unit, and ensure dynamic power balance between photovoltaic output and electrolytic load.

[0008] Further, the control of the DC / DC module on the photovoltaic side by using the maximum power point tracking algorithm and voltage threshold control specifically comprises:

[0009] A minimum voltage threshold and a safety voltage threshold are set for the intermediate direct current voltage of the photovoltaic power generation unit, the intermediate direct current voltage of the photovoltaic power generation unit is detected in real time, and the intermediate direct current voltage is compared with the set minimum voltage threshold and safety voltage threshold: when the intermediate direct current voltage of the photovoltaic power generation unit is less than the minimum voltage threshold, the DC / DC module on the photovoltaic side operates in the maximum power point tracking mode, and the output power reference value of the DC / DC module is the maximum active power of photovoltaic power generation output; when the intermediate direct current voltage of the photovoltaic power generation unit is greater than or equal to the minimum voltage threshold and less than or equal to the safety voltage threshold, the DC / DC module on the photovoltaic side is automatically switched to the constant power mode, and the output power reference value of the DC / DC module on the photovoltaic side is limited according to a linear relationship; when the intermediate direct current voltage of the photovoltaic power generation unit is greater than the safety voltage threshold, the DC / DC module on the photovoltaic side is automatically switched to the overvoltage protection mode, and the output power reference value of the DC / DC module on the photovoltaic side is adjusted to 0, so as to forcibly suppress the intermediate direct current voltage of the photovoltaic power generation unit;

[0010] Based on the output power reference value of the DC / DC module on the photovoltaic side, the real-time value of the photovoltaic power generation output voltage and the real-time value of the photovoltaic power generation output active power, the maximum power point tracking algorithm is used to dynamically adjust the duty cycle of the pulse modulation signal of the MOS tube S1 in the DC / DC module on the photovoltaic side through a PI controller, so as to control the DC / DC module on the photovoltaic side.

[0011] Further, the intermediate-level direct-current voltage of the photovoltaic power generation unit refers to the voltage between the DC / DC module and the DC / AC module on the photovoltaic side.

[0012] Further, the output power reference value of the DC / DC module on the photovoltaic side is adjusted according to a linear relationship, specifically according to the following formula:

[0013]

[0014] In the formula, the output power reference value of the DC / DC module on the photovoltaic side, the maximum active power of the photovoltaic power generation output, the linear coefficient on the photovoltaic side, the intermediate-level direct-current voltage of the photovoltaic power generation unit, the minimum voltage threshold of the intermediate-level direct-current voltage of the photovoltaic power generation unit.

[0015] Further, the DC / DC module on the hydrogen side is controlled by using a voltage threshold, specifically including:

[0016] The intermediate-level direct-current voltage of the electrolytic hydrogen production unit is set with a start voltage threshold and a maximum voltage threshold, and the intermediate-level direct-current voltage of the electrolytic hydrogen production unit is detected in real time and compared with the set start voltage threshold and maximum voltage threshold: when the intermediate-level direct-current voltage of the electrolytic hydrogen production unit is less than the start voltage threshold, the DC / DC module on the hydrogen side is in shutdown protection mode, and the output power reference value of the DC / DC module on the hydrogen side is adjusted to 0; when the intermediate-level direct-current voltage of the electrolytic hydrogen production unit is greater than or equal to the start voltage threshold and less than or equal to the maximum voltage threshold, it is automatically switched to a constant power mode, and the output power reference value of the DC / DC module on the hydrogen side is adjusted according to a linear relationship; when the intermediate-level direct-current voltage of the electrolytic hydrogen production unit is greater than the maximum voltage threshold, the output power reference value of the DC / DC module on the hydrogen side is automatically switched to a full power mode, and the output power reference value of the DC / DC module on the hydrogen side is the maximum active power input to the electrolytic tank;

[0017] Based on the output power reference value of the DC / DC module on the hydrogen side and the real-time value of the active power input to the electrolytic tank, the duty cycle of the pulse modulation signal of the MOS tube S2 in the DC / DC module on the hydrogen side is dynamically adjusted by a PI controller to realize control of the DC / DC module on the hydrogen side.

[0018] Further, the intermediate-level direct-current voltage of the electrolytic hydrogen production unit refers to the voltage between the AC / DC module and the DC / DC module on the hydrogen side.

[0019] Further, the output power reference value of the DC / DC module on the hydrogen side is adjusted according to a linear relationship, specifically according to the following formula:

[0020]

[0021] In the formula, represents the output power reference value of the hydrogen side DC / DC module, represents the maximum active power input of the electrolytic cell, represents the hydrogen production by electrolysis power consumption limit rate, represents the intermediate level DC voltage of the hydrogen production by electrolysis unit, represents the starting voltage threshold of the intermediate level DC voltage of the hydrogen production by electrolysis unit.

[0022] Further, the AC droop control method with phase control mechanism is adopted to control the DC / AC module on the photovoltaic side, which specifically includes:

[0023] In the output frequency control, the following control equation is realized:

[0024]

[0025] In the formula, represents the actual output frequency of the photovoltaic power generation unit, represents the reference output frequency of the photovoltaic power generation unit, represents the frequency droop coefficient of the DC / AC module, represents the active power output of the photovoltaic power generation, represents the frequency compensation coefficient of the DC / AC module, represents the intermediate level DC voltage of the photovoltaic power generation unit, represents the reference value of the intermediate level DC voltage of the photovoltaic power generation unit;

[0026] In the output voltage control, the following control equation is realized:

[0027]

[0028] In the formula, represents the actual network forming voltage amplitude of the photovoltaic power generation unit, represents the reference value of the network forming voltage amplitude of the photovoltaic power generation unit, represents the voltage droop coefficient of the DC / AC module, represents the reactive power output of the photovoltaic power generation;

[0029] In the output phase control, the following control equation is realized:

[0030]

[0031] In the formula, represents the output phase of the photovoltaic power generation unit, Phase compensation coefficient of DC / AC module; finally realize the regulation and control to the output frequency, voltage and phase of photovoltaic power generation unit.

[0032] Further, the AC droop control method with phase control mechanism is adopted to control the AC / DC module on the hydrogen side, specifically including:

[0033] In the output frequency control, the following control equation is realized:

[0034]

[0035] In the formula, The actual value of the output frequency of the electrolytic hydrogen production unit, The reference value of the output frequency of the electrolytic hydrogen production unit, The frequency droop coefficient of the AC / DC module, The input active power of the electrolytic cell, The frequency compensation coefficient of the AC / DC module, The intermediate DC voltage of the electrolytic hydrogen production unit, The reference value of the intermediate DC voltage of the electrolytic hydrogen production unit;

[0036] In the output voltage control, the following control equation is realized:

[0037]

[0038] In the formula, The actual value of the network-forming voltage amplitude of the electrolytic hydrogen production unit, The reference value of the network-forming voltage amplitude of the electrolytic hydrogen production unit, The voltage droop coefficient of the AC / DC module, The reactive power output by the electrolytic hydrogen production unit;

[0039] In the output phase control, the following control equation is realized:

[0040]

[0041] In the formula, The output phase of the electrolytic hydrogen production unit, The phase compensation coefficient of the AC / DC module; finally realize the regulation and control to the output frequency, voltage and phase of the electrolytic hydrogen production unit.

[0042] Compared with the prior art, the beneficial effects of the present application are:

[0043] (1) Unlike the traditional solution of storing excess photovoltaic power generation energy in chemical batteries, the present application directly uses the excess photovoltaic power generation energy for electrolytic hydrogen production through the coordinated control of the photovoltaic side and the hydrogen side, not only improves the new energy consumption rate, but also avoids many problems of photovoltaic grid connection from the root, solves the problem of bidirectional coordinated adaptive network construction and power balance between photovoltaic power generation and hydrogen production load; Specifically, the photovoltaic panel is connected to the DC / AC module output through the photovoltaic side DC / DC module (with MPPT algorithm and voltage threshold control), and the hydrogen side is connected to the electrolytic cell load through the AC / DC module and the DC / DC module (also with voltage threshold control), the double-sided coordinated adaptive network construction control method of the present application is adopted to realize electrical interconnection and energy interaction through the AC bus, ensure dynamic power balance between photovoltaic output and electrolytic load, and establish stable AC bus voltage.

[0044] (2) The present application realizes the dynamic power balance between photovoltaic output and electrolytic hydrogen production, can quickly respond by adjusting frequency, voltage and phase when photovoltaic output suddenly increases or decreases, and ensures stable operation of the overall system; The introduction of the AC bus not only enhances the interconnection and intercommunication capability of the system, but also realizes bidirectional regulation and backup between the source and the load; The photovoltaic-hydrogen double-sided coordinated network construction control designed by the present application can actively build the AC bus voltage, realize network operation without relying on external grid or energy storage under light conditions, and ensure stable system voltage; The introduction of phase control significantly improves the response speed of the output of the photovoltaic-hydrogen DC / AC module and the AC / DC module, so as to achieve the goal of dynamic power balance of photovoltaic output under environmental changes. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is the topology diagram of the photovoltaic-hydrogen double-sided coupling system of the present application;

[0046] Figure 2 is the topology diagram of the photovoltaic power generation unit of the present application;

[0047] Figure 3 is the control strategy schematic diagram of the DC / DC module of the photovoltaic side of the present application;

[0048] Figure 4 is the control strategy schematic diagram of the DC / AC module of the photovoltaic side of the present application;

[0049] Figure 5 is the topology diagram of the electrolytic hydrogen production unit of the present application;

[0050] Figure 6 is the control strategy schematic diagram of the AC / DC module of the hydrogen side of the present application;

[0051] Figure 7 is the control strategy schematic diagram of the DC / DC module of the hydrogen side of the present application;

[0052] Figure 8 is a schematic diagram of the variation of the intermediate DC voltage of the photovoltaic irradiance increase triggered photovoltaic power generation unit and the electrolytic hydrogen generation unit of the present invention;

[0053] Figure 9 is a schematic diagram of the variation of the photovoltaic power generation output active power of the photovoltaic side and the electrolytic cell input active power of the hydrogen side triggered by the photovoltaic irradiance increase of the present invention;

[0054] Figure 10 is a schematic diagram of the variation of the AC voltage (i.e. AC bus voltage) triggered by the photovoltaic irradiance increase of the present invention;

[0055] Figure 11 is a schematic diagram of the variation of the AC frequency (i.e. AC bus frequency) triggered by the photovoltaic irradiance increase of the present invention. DETAILED DESCRIPTION

[0056] The detailed description set forth below in connection with the appended drawings describes exemplary embodiments and does not represent the only embodiments consistent with the invention. The term "exemplary" used throughout this description means "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other embodiments. The following detailed description includes specific

[0057] The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It also will be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0058] It will be understood that, although the terms first, second, third, etc. can be used herein to describe various information, these terms are not intended to denote a temporal or chronological order. Rather, these terms are used only as a shorthand notation to first, second, third, etc. pieces of information. For example, a first piece of information can later come to be referred to as a second piece of information without departing from the scope of the present invention. As used herein, the term "if' can be construed to mean "when" or "in response to determining" or "in response to a determination" that a certain condition precedent has been satisfied or obtained, unless and except the context clearly indicates otherwise.

[0059] The present invention is described in detail below with reference to the attached drawing figures. Features of the embodiments and implementation forms described below can be combined with each other, if not in conflict.

[0060] The light-hydrogen bilateral collaborative adaptive network construction control method of the application is applied to a light-hydrogen bilateral coupling system, the core of the system is to realize flexible interconnection of the photovoltaic power generation unit and the electrolytic hydrogen production unit through an alternating current bus, the photovoltaic power generation unit and the electrolytic hydrogen production unit are directly connected through the alternating current bus, forming an independent light-hydrogen interconnection system, the system does not need to rely on communication, and can make the electrolytic hydrogen production unit realize on-site flexible consumption of the photovoltaic side power under fluctuating conditions, guarantee real-time balance of light-hydrogen bilateral power, and cooperatively build a stable alternating current bus voltage; meanwhile, the system adopts an improved droop control strategy and a phase collaborative adjustment mechanism, ensuring stable operation of the system under dynamic power fluctuation. The light-hydrogen bilateral collaborative adaptive network construction control method realizes alternating current bus voltage construction and light-hydrogen power dynamic balance.

[0061] As shown in Figure 1 , the light-hydrogen bilateral coupling system includes a photovoltaic power generation unit, an electrolytic hydrogen production unit and an alternating current bus (AC BUS). The photovoltaic power generation unit and the electrolytic hydrogen production unit are directly connected through the alternating current bus, specifically through coupling points PCC1 / PCC2, so that the photovoltaic side and the hydrogen side can realize bidirectional exchange and balanced scheduling of electric energy during dynamic power regulation, and ensure bidirectional exchange and balanced scheduling of electric energy; the photovoltaic power generation unit adopts a two-stage photovoltaic power generation architecture, specifically including a photovoltaic panel, a DC / DC module and a DC / AC module, the photovoltaic panel is connected with the DC / DC module and the DC / AC module through the DC / DC module on the photovoltaic side; the electrolytic hydrogen production unit includes an AC / DC module, a DC / DC module and an electrolytic tank, the electrolytic tank is connected with the DC / DC module and the AC / DC module through the DC / DC module on the hydrogen side. In the system, the photovoltaic side and the hydrogen side not only perform power control on the direct current side respectively, but also realize direct electric energy interconnection through the alternating current bus, so that the two sides can work cooperatively in system regulation, and further improve the anti-interference ability and dynamic response speed of the overall system.

[0062] The topology of the photovoltaic power generation unit is shown in Figure 2 , which includes a photovoltaic panel, a DC / DC module and a DC / AC module, the DC / DC module on the photovoltaic side adopts a Buck circuit, and the Buck circuit and each component in the DC / AC module and the connection relationship therebetween are specifically shown in Figure 2 , which is a commonly used Buck circuit and DC / AC module in the field, and will not be described here.

[0063] The topology of the electrolytic hydrogen production unit is shown in Figure 5 , which includes an AC / DC module, a DC / DC module and an electrolytic tank, the DC / DC module on the hydrogen side adopts a Buck circuit, and the Buck circuit and each component in the AC / DC module and the connection relationship therebetween are specifically shown in Figure 5 , which is a commonly used Buck circuit and AC / DC module in the field, and will not be described here.

[0064] It should be noted that the DC / AC module on the photovoltaic side and the AC / DC module on the hydrogen side are both filtered by LCL filters, wherein the corresponding inductance and capacitance in the DC / AC module are and , and the inductive capacitance voltage is ; the corresponding inductance and capacitance in the AC / DC module are and , and the inductive capacitance voltage is .

[0065] In this embodiment, the control method specifically includes: using a maximum power point tracking (MPPT) algorithm and voltage threshold control to control the DC / DC module on the photovoltaic side, so that it runs in a maximum power point tracking mode or a constant power mode or an overvoltage protection mode, to maximize the energy capture efficiency as much as possible; using voltage threshold control to control the DC / DC module on the hydrogen side, so that it runs in a shutdown protection mode or a constant power mode or a full power mode; using an AC droop control method with a phase control mechanism to control the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side, to regulate the output frequency, voltage and phase of the corresponding photovoltaic power generation unit or electrolytic hydrogen production unit, to ensure dynamic power balance between photovoltaic output and electrolytic load, so that the system can still maintain power balance on both the photovoltaic side and the hydrogen side when the photovoltaic output fluctuates or the electrolytic load changes.

[0066] Further, as shown in Figure 1 , and are all outside the DC / DC module and the DC / AC module and the AC / DC module, wherein is an intermediate DC voltage, so the intermediate DC voltage includes an intermediate DC voltage of the photovoltaic power generation unit and an intermediate DC voltage of the electrolytic hydrogen production unit , wherein the intermediate DC voltage of the photovoltaic power generation unit refers to the voltage between the DC / DC module and the DC / AC module on the photovoltaic side; the intermediate DC voltage of the electrolytic hydrogen production unit refers to the voltage between the AC / DC module and the DC / DC module on the hydrogen side.

[0067] Further, as shown in Figure 3As shown, the maximum power point tracking algorithm and voltage threshold control are used to control the DC / DC module on the photovoltaic side, specifically including: setting a minimum voltage threshold and a safety voltage threshold for the intermediate stage DC voltage of the photovoltaic power generation unit, real-time detecting the intermediate stage DC voltage of the photovoltaic power generation unit, and comparing it with the set minimum voltage threshold and safety voltage threshold; when the intermediate stage DC voltage of the photovoltaic power generation unit is less than the minimum voltage threshold, the DC / DC module on the photovoltaic side operates in the maximum power point tracking mode, and the output power reference value thereof is the maximum active power of the photovoltaic power generation output, realizing maximum power point tracking and maximizing the active power of the photovoltaic power generation output; when the intermediate stage DC voltage of the photovoltaic power generation unit is greater than or equal to the minimum voltage threshold and less than or equal to the safety voltage threshold, it is automatically switched to the constant power mode, limiting the photovoltaic output, i.e. limiting the output power reference value of the DC / DC module on the photovoltaic side according to a linear relationship; when the intermediate stage DC voltage of the photovoltaic power generation unit is greater than the safety voltage threshold, it is automatically switched to the overvoltage protection mode, adjusting the output power reference value of the DC / DC module on the photovoltaic side to 0, forcibly suppressing the intermediate stage DC voltage of the photovoltaic power generation unit to be less than or equal to the safety voltage threshold, ensuring the stability of the corresponding intermediate stage DC voltage, preventing overvoltage of the intermediate stage DC voltage, and ensuring safe operation of the equipment. After that, the photovoltaic power generation output voltage is detected in real time based on the output power reference value of the DC / DC module on the photovoltaic side, the real-time value of the photovoltaic power generation output voltage, and the real-time value of the active power of the photovoltaic power generation output, the MPPT algorithm is used to dynamically adjust the duty cycle of the pulse modulation (PWM) signal of MOS tube S1 in the DC / DC module on the photovoltaic side through the PI controller , realizing control of the DC / DC module on the photovoltaic side, wherein is the PWM signal driving MOS tube S1 in the Buck circuit of the photovoltaic power generation unit, and the working state of the photovoltaic panel can be adjusted by adjusting the duty cycle thereof. According to the linear relationship, the output power reference value of the DC / DC module on the photovoltaic side is limited, and the adjustment is specifically made according to the following formula:

[0068]

[0069] In the formula, represents the output power reference value of the DC / DC module on the photovoltaic side, represents the maximum active power of the photovoltaic power generation output, represents the photovoltaic power generation output power limitation rate, represents the intermediate stage DC voltage of the photovoltaic power generation unit, represents the minimum voltage threshold of the intermediate stage DC voltage of the photovoltaic power generation unit.

[0070] From the above, it can be seen that the control law of the photovoltaic-side DC / DC module can be expressed as:

[0071]

[0072] In the formula, This represents the safe voltage threshold for the intermediate DC voltage of the photovoltaic power generation unit. Then, the traditional DC / DC module control strategy incorporating the MPPT algorithm is used to adjust... The duty cycle is adjusted to regulate the operating status of the DC / DC module on the photovoltaic side.

[0073] Furthermore, such as Figure 7 As shown, voltage threshold control is used to control the DC / DC module on the hydrogen side. Specifically, this includes setting a start-up voltage threshold and a maximum voltage threshold for the intermediate-stage DC voltage of the hydrogen electrolysis unit; real-time monitoring of the intermediate-stage DC voltage of the hydrogen electrolysis unit and comparing it with the set start-up voltage threshold and maximum voltage threshold; when the intermediate-stage DC voltage of the hydrogen electrolysis unit is less than the start-up voltage threshold, the hydrogen-side DC / DC module operates in shutdown protection mode, adjusting the output power reference value of the hydrogen-side DC / DC module to 0, making it greater than or equal to the start-up voltage threshold, ensuring the safe start-up of the electrolyzer, thereby guaranteeing the continuity and safety of the hydrogen production process; when the intermediate-stage DC voltage of the hydrogen electrolysis unit is greater than or equal to... When the starting voltage threshold is less than or equal to the maximum voltage threshold, the system automatically switches to constant power mode. The output power reference value of the hydrogen-side DC / DC module is adjusted linearly, allowing the hydrogen-side DC / DC module to absorb load demand at maximum power, achieving maximum efficiency tracking and prioritizing the electrolyzer's input power requirements. When the intermediate-stage DC voltage of the hydrogen electrolysis unit exceeds the maximum voltage threshold, the system automatically switches to full-power mode. The output power reference value of the hydrogen-side DC / DC module is the maximum active power input to the electrolyzer. By reducing the active power input to the electrolyzer, the system prevents overvoltage of the corresponding intermediate-stage DC voltage, stabilizes the intermediate-stage DC voltage, and avoids overvoltage damage to the electrolyzer ports. Subsequently, based on the output power reference value of the hydrogen-side DC / DC module and the real-time value of the electrolyzer's input active power, the PI controller dynamically adjusts the pulse modulation (PWM) signal of the MOSFET S2 in the hydrogen-side DC / DC module. The duty cycle causes the current to Track its current reference value This enables control of the DC / DC module on the hydrogen side, thereby regulating the active power input to the electrolyzer and ensuring timely absorption of excess electrical energy during photovoltaic power fluctuations. To drive the PWM signal of MOS tube S2 in the Buck circuit of the electrolytic hydrogen production unit, the input power of the electrolytic cell can be adjusted by adjusting the duty cycle, thereby maximizing the hydrogen production efficiency. According to a linear relationship, the output power reference value of the DC / DC module on the hydrogen side is adjusted according to the following formula:

[0074]

[0075] In the formula, represents the output power reference value of the DC / DC module on the hydrogen side, represents the maximum active power input of the electrolytic cell, represents the hydrogen production power consumption limit rate, represents the intermediate direct current voltage of the electrolytic hydrogen production unit, represents the starting voltage threshold of the intermediate direct current voltage of the electrolytic hydrogen production unit.

[0076] From the above, the control law of the DC / DC module on the hydrogen side can be represented as:

[0077]

[0078] In the formula, represents the maximum voltage threshold of the intermediate direct current voltage of the electrolytic hydrogen production unit. Further, the duty cycle of is adjusted by using the traditional current control DC / DC module control strategy to adjust the active power input of the electrolytic cell, thereby maximizing the hydrogen production efficiency.

[0079] Further, as shown in Figure 4 , the AC droop control method with phase control mechanism is used to control the DC / AC module on the photovoltaic side, which specifically includes: ① in the output frequency control, the following control equation is realized:

[0080]

[0081] In the formula, represents the actual output frequency of the photovoltaic power generation unit, represents the reference output frequency of the photovoltaic power generation unit, represents the frequency droop coefficient of the DC / AC module, represents the active power output of the photovoltaic power generation, represents the frequency compensation coefficient of the DC / AC module, represents the intermediate direct current voltage of the photovoltaic power generation unit, represents the reference value of the intermediate direct current voltage of the photovoltaic power generation unit.

[0082] ② in the output voltage control, the following control equation is realized: ​

[0083]

[0084] In the formula, represents the actual value of the grid-forming voltage amplitude of the photovoltaic power generation unit, represents the reference value of the grid-forming voltage amplitude of the photovoltaic power generation unit, represents the voltage droop coefficient of the DC / AC module, represents the reactive power of the photovoltaic power generation output.

[0085] ③In the output phase control, the following control equation is realized:

[0086]

[0087] In the formula, represents the output phase of the photovoltaic power generation unit, represents the phase compensation coefficient of the DC / AC module. Finally, the output frequency, voltage and phase of the photovoltaic power generation unit are regulated to ensure dynamic power balance between photovoltaic output and electrolysis load, so that the system can maintain power balance on both sides of light-hydrogen when the photovoltaic output fluctuates or the electrolysis load changes.

[0088] Specifically, the DC / AC module on the photovoltaic side adopts an AC droop control method with a phase control mechanism, that is, an AC droop control method is adopted, and at the same time, the power outer loop uses a droop control with phase control. In the output frequency control, the system frequency is dynamically adjusted by introducing the power deviation of the phase , realizing the light-hydrogen power balance and accelerating the response speed of the DC / AC module control; using the corresponding frequency control equation, the power deviation and the intermediate level DC voltage deviation are coupled to dynamically adjust the system frequency, ensuring the power balance between photovoltaic output and electrolytic hydrogen production. In the output voltage control, the traditional droop control method is continued, and the voltage amplitude is linearly related to the reactive power; through the corresponding voltage control equation, the reactive power is adjusted to realize accurate control of the voltage amplitude, effectively alleviating voltage fluctuations. The phase control term is introduced, and the output phase of the DC / AC module is adjusted in real time according to the intermediate level DC voltage deviation of the photovoltaic power generation unit, ensuring synchronous operation with the AC bus in the grid-connected mode while accelerating the response speed; the phase control mechanism based on the intermediate level DC voltage deviation is introduced, that is, the corresponding phase control equation, to improve the response speed of the DC / AC module output, so that even in the case of severe load fluctuations, the source hydrogen side can also maintain synchronous operation. In the double closed-loop control, the inner current loop realizes fast current tracking, and the outer voltage loop stabilizes the corresponding intermediate level DC voltage .

[0089] Further, as Figure 6As shown, the AC droop control method with phase control mechanism is used to control the AC / DC module on the hydrogen side, specifically including: ① in the output frequency control, the following control equation is used to realize:

[0090]

[0091] In the formula, represents the actual output frequency of the electrolytic hydrogen production unit, represents the reference output frequency of the electrolytic hydrogen production unit, represents the frequency droop coefficient of the AC / DC module, represents the input active power of the electrolytic cell, represents the frequency compensation coefficient of the AC / DC module, represents the intermediate DC voltage of the electrolytic hydrogen production unit, represents the reference intermediate DC voltage of the electrolytic hydrogen production unit.

[0092] ② in the output voltage control, the following control equation is used to realize:

[0093]

[0094] In the formula, represents the actual network voltage amplitude of the electrolytic hydrogen production unit, represents the reference network voltage amplitude of the electrolytic hydrogen production unit, represents the voltage droop coefficient of the AC / DC module, represents the reactive power output by the electrolytic hydrogen production unit.

[0095] ③ in the output phase control, the following control equation is used to realize:

[0096]

[0097] In the formula, represents the output phase of the electrolytic hydrogen production unit, represents the phase compensation coefficient of the AC / DC module. Finally, the output frequency, voltage and phase of the electrolytic hydrogen production unit are regulated to ensure dynamic power balance between photovoltaic output and electrolytic load, so that the system can maintain power balance on both light and hydrogen sides when photovoltaic output fluctuates or electrolytic load changes.

[0098] Specifically, the AC / DC module on the hydrogen side also uses the AC droop control method with phase control mechanism. In the output frequency control, the active power obtained by the traditional frequency droop formula and the system frequency obtained by introducing the phase are used to realize: By utilizing the corresponding frequency control equation, the power deviation is coupled with the intermediate-stage DC voltage deviation to dynamically adjust the system frequency, ensuring power balance between photovoltaic output and electrolytic hydrogen production. For output voltage control, the traditional droop control method is still used, ensuring a linear relationship between voltage amplitude and reactive power. Reactive power regulation is achieved through the corresponding voltage control equation to precisely control the voltage amplitude, effectively mitigating voltage fluctuations. Simultaneously, a phase control stage is added to adjust the output phase of the AC / DC module in real time based on changes in the intermediate-stage DC voltage of the electrolytic hydrogen production unit, ensuring synchronous operation in grid-connected mode while improving response speed. A phase control mechanism based on the intermediate-stage DC voltage deviation, i.e., the corresponding phase control equation, is introduced to improve the response speed of the DC / AC module output, maintaining synchronous operation on the hydrogen source side even under severe load fluctuations. In the dual-loop control structure, the inner current loop achieves rapid current tracking, while the outer voltage loop ensures the corresponding intermediate-stage DC voltage. Stability.

[0099] It should be noted that increased photovoltaic irradiance will cause changes in intermediate stage DC voltage, photovoltaic power output active power, electrolytic cell input active power, AC voltage, and AC frequency. For example, Figure 8 The intermediate DC voltage of the photovoltaic power generation unit and the electrolysis hydrogen production unit was demonstrated. Changes, Figure 9 This demonstrates the active power output of photovoltaic power generation on the photovoltaic side. Active power input to the electrolyzer on the hydrogen side Changes, Figure 10 This demonstrates the change in AC bus voltage V. Figure 11 The experiment demonstrated the change in AC bus frequency f. In the experiment, the photovoltaic irradiance was set to increase in steps at 1.5s, 2s, and 2.5s. Within 2s after the 1.5s photovoltaic irradiance step increase and within 2s after the 2s photovoltaic irradiance step increase, the photovoltaic side operated in MPPT mode, and the hydrogen side absorbed maximum power. At this time, the 1.5s photovoltaic irradiance increase triggered an increase in hydrogen production power, and the intermediate DC voltage of the photovoltaic power generation unit... The intermediate DC voltage of the electrolysis hydrogen production unit continues to rise. After rising, it remains stable; the active power output of photovoltaic power generation on the photovoltaic side. Active power input to the electrolyzer on the hydrogen side The AC bus frequency f stabilizes after rising. Within 3 seconds of a step increase in photovoltaic irradiance over 2.5 seconds, the hydrogen side reaches its hydrogen production limit and restricts power absorption, while the photovoltaic side exits MPPT mode and restricts photovoltaic output. At this time, the intermediate DC voltage of the photovoltaic power generation unit increases by 2.5 seconds. After rising, the DC voltage of the intermediate stage of the electrolysis hydrogen production unit remains stable. After rising, due to reaching the upper limit of hydrogen production, then falling to stable; the photovoltaic side photovoltaic power generation output active power and the hydrogen side electrolytic cell input active power and the alternating current bus frequency f rises and then falls to stable.

[0100] Figure 9 The photovoltaic power generation power and the hydrogen side absorption power change, which expresses that the system power realizes dynamic balance after the photovoltaic irradiance increases. Figure 10 The three-phase alternating current voltage diagram of 2s-2.1s can be seen that after the photovoltaic irradiance increases, the alternating current bus voltage also always maintains stable and the amplitude is consistent. Combined with Figure 10 and Figure 11 The network configuration control method of the present application can still maintain the network configuration effect of system stability after the photovoltaic irradiance increases. Comprehensive Figures 8-11 It can be seen that the network configuration control method of the present application has the ability to solve the problems of stable network configuration of photovoltaic-hydrogen coupling system and power dynamic balance between photovoltaic output and electrolytic hydrogen production.

[0101] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for light-hydrogen dual-edge cooperative adaptive networking control, characterized in that, The application is applied to a light-hydrogen double-side coupling system, the system comprising a photovoltaic power generation unit, an electrolytic hydrogen production unit and an alternating current bus, wherein the photovoltaic power generation unit and the electrolytic hydrogen production unit are directly connected through the alternating current bus; the photovoltaic power generation unit comprises photovoltaic panels, a DC / DC module and a DC / AC module connected in sequence; the electrolytic hydrogen production unit comprises an AC / DC module, a DC / DC module and an electrolytic cell connected in sequence; The method specifically comprises: controlling the DC / DC module on the photovoltaic side by using a maximum power point tracking algorithm and voltage threshold control, so that the DC / DC module operates in a maximum power point tracking mode, a constant power mode or an overvoltage protection mode; controlling the DC / DC module on the hydrogen side by using voltage threshold control, so that the DC / DC module operates in a shutdown protection mode, a constant power mode or a full power mode; controlling the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side by using an alternating current droop control method with a phase control mechanism, so as to regulate the output frequency, voltage and phase of the corresponding photovoltaic power generation unit or electrolytic hydrogen production unit, and ensure dynamic power balance between photovoltaic output and electrolytic load. The AC / DC module on the hydrogen side is controlled by using the alternating current droop control method with the phase control mechanism, and the control specifically comprises: In output frequency control, the following control equation is used: ； In the formula, represents the output frequency actual value of the photovoltaic power generation unit, represents the output frequency reference value of the photovoltaic power generation unit, represents the frequency droop coefficient of the DC / AC module, represents the photovoltaic power generation output active power, represents the frequency compensation coefficient of the DC / AC module, represents the intermediate stage DC voltage of the photovoltaic power generation unit, represents the intermediate stage DC voltage reference value of the photovoltaic power generation unit; In output voltage control, the following control equation is used: ； In the formula, represents the actual value of the grid-forming voltage amplitude of the photovoltaic power generation unit, represents the reference value of the grid-forming voltage amplitude of the photovoltaic power generation unit, represents the voltage droop coefficient of the DC / AC module, represents the reactive power of the photovoltaic power generation output; In output phase control, the following control equation is used: ； In the formula, represents the output phase of the photovoltaic power generation unit, represents the phase compensation coefficient of the DC / AC module; finally realizes the regulation of the output frequency, voltage and phase of the photovoltaic power generation unit.

2. The light-hydrogen dual side cooperative adaptive networking control method according to claim 1, characterized in that, The DC / DC module on the photovoltaic side is controlled by using the maximum power point tracking algorithm and voltage threshold control, and the control specifically comprises: A minimum voltage threshold and a safety voltage threshold are set for the intermediate direct current voltage of the photovoltaic power generation unit, the intermediate direct current voltage of the photovoltaic power generation unit is detected in real time, and the intermediate direct current voltage is compared with the set minimum voltage threshold and safety voltage threshold: when the intermediate direct current voltage of the photovoltaic power generation unit is less than the minimum voltage threshold, the DC / DC module on the photovoltaic side operates in the maximum power point tracking mode, and the output power reference value of the DC / DC module is the maximum active power of photovoltaic power generation output; when the intermediate direct current voltage of the photovoltaic power generation unit is greater than or equal to the minimum voltage threshold and less than or equal to the safety voltage threshold, the DC / DC module on the photovoltaic side is automatically switched to the constant power mode, and the output power reference value of the DC / DC module is limited according to a linear relationship; when the intermediate direct current voltage of the photovoltaic power generation unit is greater than the safety voltage threshold, the DC / DC module on the photovoltaic side is automatically switched to the overvoltage protection mode, and the output power reference value of the DC / DC module is adjusted to 0, so as to forcibly suppress the intermediate direct current voltage of the photovoltaic power generation unit; Based on the output power reference value of the DC / DC module on the photovoltaic side, the real-time value of the photovoltaic power generation output voltage and the real-time value of the photovoltaic power generation output active power, the maximum power point tracking algorithm is used to dynamically adjust the duty cycle of the pulse modulation signal of the MOS tube S1 in the DC / DC module on the photovoltaic side through a PI controller, so as to control the DC / DC module on the photovoltaic side. 3.The light-hydrogen dual-edge cooperative adaptive networking control method of claim 2, wherein, The intermediate direct current voltage of the photovoltaic power generation unit refers to the voltage between the DC / DC module and the DC / AC module on the photovoltaic side. 4.The light-hydrogen dual-edge cooperative adaptive networking control method of claim 2, wherein, The output power reference value of the DC / DC module on the photovoltaic side is limited according to a linear relationship, and the adjustment is specifically performed according to the following formula: ； In the formula, represents the output power reference value of the DC / DC module on the photovoltaic side, represents the maximum active power of the photovoltaic power generation output, represents the linear coefficient on the photovoltaic side, represents the intermediate-stage DC voltage of the photovoltaic power generation unit, represents the minimum voltage threshold of the intermediate-stage DC voltage of the photovoltaic power generation unit.

5. The light-hydrogen dual side cooperative adaptive networking control method according to claim 1, characterized in that, The DC / DC module on the hydrogen side is controlled by using voltage threshold control, and the control specifically includes: The start voltage threshold and the maximum voltage threshold are set for the intermediate direct-current voltage of the electrolytic hydrogen production unit, the intermediate direct-current voltage of the electrolytic hydrogen production unit is detected in real time, and the intermediate direct-current voltage is compared with the set start voltage threshold and maximum voltage threshold: when the intermediate direct-current voltage of the electrolytic hydrogen production unit is less than the start voltage threshold, the DC / DC module on the hydrogen side is operated in a shutdown protection mode, and the output power reference value of the DC / DC module on the hydrogen side is adjusted to 0; when the intermediate direct-current voltage of the electrolytic hydrogen production unit is greater than or equal to the start voltage threshold and less than or equal to the maximum voltage threshold, the constant power mode is automatically switched to, and the output power reference value of the DC / DC module on the hydrogen side is adjusted according to a linear relationship; when the intermediate direct-current voltage of the electrolytic hydrogen production unit is greater than the maximum voltage threshold, the full power mode is automatically switched to, and the output power reference value of the DC / DC module on the hydrogen side is the maximum active power input of the electrolytic cell. Based on the output power reference value of the DC / DC module on the hydrogen side and the real-time value of the active power input of the electrolytic cell, the duty cycle of the pulse modulation signal of the MOS tube S2 in the DC / DC module on the hydrogen side is dynamically adjusted by a PI controller to realize the control of the DC / DC module on the hydrogen side.

6. The light-hydrogen dual side cooperative adaptive networking control method according to claim 5, characterized in that, The intermediate direct-current voltage of the electrolytic hydrogen production unit refers to the voltage between the AC / DC module on the hydrogen side and the DC / DC module.

7. The light-hydrogen dual side cooperative adaptive networking control method according to claim 5, characterized in that, The output power reference value of the DC / DC module on the hydrogen side is adjusted according to a linear relationship, and the adjustment is specifically performed according to the following formula: ； In the formula, represents the output power reference value of the DC / DC module on the hydrogen side, represents the maximum active power input to the electrolyzer, represents the hydrogen production power accommodation limit rate of the electrolyzer, represents the intermediate-level direct-current voltage of the hydrogen production unit, represents the starting voltage threshold of the intermediate-level direct-current voltage of the hydrogen production unit. 8.The light-hydrogen dual-edge cooperative adaptive networking control method of claim 1, wherein, The AC / DC module on the hydrogen side is controlled by using an AC droop control method with a phase control mechanism, and the control specifically includes: In output frequency control, the following control equation is used to realize the control: ； wherein represents the output frequency actual value of the electrolytic hydrogen production unit, represents the output frequency reference value of the electrolytic hydrogen production unit, represents the frequency droop coefficient of the AC / DC module, represents the electrolyzer input active power, represents the frequency compensation coefficient of the AC / DC module, represents the intermediate stage DC voltage of the electrolytic hydrogen production unit, represents the intermediate stage DC voltage reference value of the electrolytic hydrogen production unit; In output voltage control, the following control equation is used to realize the control: ； In the formula, represents the actual value of the network-forming voltage amplitude of the electrolytic hydrogen production unit, represents the reference value of the network-forming voltage amplitude of the electrolytic hydrogen production unit, represents the voltage droop coefficient of the AC / DC module, represents the reactive power output by the electrolytic hydrogen production unit; In output phase control, the following control equation is used to realize the control: ； In the formula, represents the output phase of the electrolytic hydrogen production unit, represents the phase compensation coefficient of the AC / DC module; ultimately realizing the regulation of the output frequency, voltage and phase of the electrolytic hydrogen production unit.

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