Light-hydrogen bilateral collaborative self-adaptive network construction control method

Abstract

The invention discloses a light-hydrogen bilateral collaborative self-adaptive network construction control method, which is applied to a light-hydrogen bilateral coupling system, the system comprises 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 comprises a photovoltaic panel, a DC / DC module and a DC / AC module, and the electrolytic hydrogen production unit comprises 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 a DC / DC module on a photovoltaic side, adopts voltage threshold control to control a DC / DC module on a hydrogen side, and adopts an alternating current droop control method introducing a phase control mechanism to control a DC / AC module or an AC / DC module. Therefore, the output frequency, the voltage and the phase of the corresponding photovoltaic power generation unit or the electrolytic hydrogen production unit are regulated and controlled, and dynamic power balance is ensured to be formed between the photovoltaic output and the electrolytic load. Two-way adjustment can be carried out, and stable operation of the system is ensured.

Description

Technical Field

[0001] This invention belongs to the field of collaborative control technology in the new energy field, specifically relating to the field of photovoltaic-hydrogen bilateral collaborative control technology, and particularly to a photovoltaic-hydrogen bilateral collaborative adaptive network control method. Background Technology

[0002] As the installed capacity of photovoltaic power generation continues to climb, the challenges to system stability brought about by its increasing penetration rate are becoming increasingly prominent. Unlike the stable output characteristics of traditional thermal power units, photovoltaic power generation has significant intermittent and fluctuating characteristics. Under the influence of natural factors such as day-night alternation and cloud cover, its output power fluctuates on the order of minutes or even seconds, resulting in severe frequency and voltage regulation pressure on the power grid.

[0003] Hydrogen energy, as a highly promising energy carrier in new power systems, boasts a mass energy density as high as 142 MJ / kg (approximately three times that of gasoline), and can achieve bidirectional conversion between electricity and hydrogen through water electrolysis. This characteristic allows hydrogen energy systems to both smooth out photovoltaic power fluctuations and convert excess electrical energy into clean fuels that can be stored for extended periods, providing an innovative path for constructing multi-timescale energy storage systems. However, existing photovoltaic-hydrogen systems primarily employ DC bus coupling, which, while simplifying the system structure, suffers from drawbacks such as high fault propagation risk, difficulty in fault isolation, and challenges in interacting with the AC grid. Furthermore, the photovoltaic output is directly affected by environmental factors such as sunlight and temperature, resulting in significant fluctuations. If the output mismatches with the dynamic power response of the electrolyzer, the imbalanced power can easily lead to system voltage exceeding limits, potentially triggering a cascading failure in the DC-coupled system.

[0004] To address the aforementioned challenges, this invention proposes a control strategy for a photovoltaic-hydrogen system comprising photovoltaic power generation units and electrolytic hydrogen production units interconnected via an AC bus. The strategy includes: First, a bilateral collaborative grid-connected control strategy is designed for the AC / DC converters of both the photovoltaic and hydrogen production units. Intermediate DC voltage deviations from the photovoltaic and hydrogen sides are incorporated into the frequency and phase angle control to correct for reference values, achieving grid-connected control, improving system dynamic response, and characterizing the power distribution of photovoltaic-hydrogen. Second, an adaptive power collaborative control strategy based on the intermediate DC voltage is designed for the DC / DC converters of both the photovoltaic and hydrogen sides. This achieves dynamic power balance between photovoltaic power generation and hydrogen production, preventing voltage collapse caused by system power imbalance. The proposed method solves the problems of stable grid connection and dynamic power balance in photovoltaic-hydrogen coupling systems, providing a synergistic technical framework for future high-penetration photovoltaic consumption and green hydrogen production. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a light-hydrogen bilateral cooperative adaptive network control method.

[0006] The objective of this invention is achieved through the following technical solution: a photovoltaic-hydrogen bilateral cooperative adaptive grid control method, applied to a photovoltaic-hydrogen bilateral coupling system, which includes a photovoltaic power generation unit, an electrolysis hydrogen production unit, and an AC bus, wherein the photovoltaic power generation unit and the electrolysis hydrogen production unit are directly connected through the AC bus; the photovoltaic power generation unit includes a photovoltaic panel, a DC / DC module, and a DC / AC module connected in sequence; the electrolysis hydrogen production unit includes an AC / DC module, a DC / DC module, and an electrolyzer connected in sequence; The method specifically includes: using a maximum power point tracking algorithm and voltage threshold control to control the DC / DC module on the photovoltaic side, so that it operates in maximum power point tracking mode, constant power mode, or overvoltage protection mode; using voltage threshold control to control the DC / DC module on the hydrogen side, so that it operates in shutdown protection mode, constant power mode, or full power mode; and using an AC droop control method with phase control mechanism to control the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side, so as to regulate the output frequency, voltage, and phase of the corresponding photovoltaic power generation unit or electrolysis hydrogen production unit, and ensure that a dynamic power balance is formed between photovoltaic output and electrolysis load.

[0007] Furthermore, the control of the photovoltaic-side DC / DC module using the maximum power point tracking algorithm and voltage threshold control specifically includes: A minimum voltage threshold and a safe voltage threshold are set for the intermediate DC voltage of the photovoltaic (PV) power generation unit. The intermediate DC voltage of the PV power generation unit is detected in real time and compared with the set minimum voltage threshold and safe voltage threshold. When the intermediate DC voltage of the PV power generation unit is less than the minimum voltage threshold, the DC / DC module on the PV side operates in maximum power point tracking mode, and its output power reference value is the maximum active power output of the PV power generation unit. When the intermediate DC voltage of the PV power generation unit is greater than or equal to the minimum voltage threshold and less than or equal to the safe voltage threshold, it automatically switches to constant power mode and limits the output power reference value of the DC / DC module on the PV side according to a linear relationship. When the intermediate DC voltage of the PV power generation unit is greater than the safe voltage threshold, it automatically switches to overvoltage protection mode and adjusts the output power reference value of the DC / DC module on the PV side to 0 to forcibly suppress the intermediate DC voltage of the PV power generation unit. Based on the output power reference value of the photovoltaic-side DC / DC module, the real-time output voltage value of photovoltaic power generation, and the real-time output active power value of photovoltaic power generation, the maximum power point tracking algorithm is used to dynamically adjust the duty cycle of the pulse modulation signal of MOSFET S1 in the photovoltaic-side DC / DC module through a PI controller, thereby realizing the control of the photovoltaic-side DC / DC module.

[0008] Furthermore, 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.

[0009] Furthermore, the reference value for limiting the output power of the photovoltaic-side DC / DC module according to a linear relationship is specifically adjusted according to the following formula:

[0010] In the formula, This indicates the reference value for the output power of the DC / DC module on the photovoltaic side. This indicates the maximum active power output of photovoltaic power generation. Indicates the linearity coefficient on the photovoltaic side. This represents the intermediate DC voltage of the photovoltaic power generation unit. This represents the minimum voltage threshold of the intermediate DC voltage of a photovoltaic power generation unit.

[0011] Furthermore, the control of the hydrogen-side DC / DC module using voltage threshold control specifically includes: A start-up voltage threshold and a maximum voltage threshold are set for the intermediate stage DC voltage of the hydrogen electrolysis unit. The intermediate stage DC voltage of the hydrogen electrolysis unit is monitored in real time and compared 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 DC / DC module on the hydrogen side operates 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 stage DC voltage of the hydrogen electrolysis unit is greater than or equal to the start-up voltage threshold and less than or equal to the maximum voltage threshold, it automatically switches to 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 stage DC voltage of the hydrogen electrolysis unit is greater than the maximum voltage threshold, it automatically switches to 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 electrolyzer. Based on the reference value of the output power of the DC / DC module on the hydrogen side and the real-time value of the active power input to the electrolyzer, the duty cycle of the pulse modulation signal of the MOS transistor S2 in the DC / DC module on the hydrogen side is dynamically adjusted by the PI controller to achieve control of the DC / DC module on the hydrogen side.

[0012] Furthermore, 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.

[0013] Furthermore, the adjustment of the output power reference value of the hydrogen-side DC / DC module according to a linear relationship is specifically based on the following formula:

[0014] In the formula, This indicates the reference value for the output power of the DC / DC module on the hydrogen side. This indicates the maximum active power input to the electrolytic cell. Indicates the power limitation rate for hydrogen production via electrolysis. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This represents the start-up voltage threshold of the intermediate stage DC voltage in the electrolysis hydrogen production unit.

[0015] Furthermore, an AC droop control method incorporating a phase control mechanism is used to control the DC / AC module on the photovoltaic side, specifically including: The output frequency control is achieved based on the following control equation:

[0016] In the formula, This represents the actual output frequency of the photovoltaic power generation unit. This indicates the reference value for the output frequency of the photovoltaic power generation unit. This represents the frequency droop factor of the DC / AC module. Indicates the active power output of photovoltaic power generation. This represents the frequency compensation coefficient of the DC / AC module. This represents the intermediate DC voltage of the photovoltaic power generation unit. This indicates the reference value for the intermediate stage DC voltage of the photovoltaic power generation unit; The output voltage control is achieved based on the following control equation:

[0017] In the formula, This represents the actual value of the grid voltage amplitude of the photovoltaic power generation unit. This indicates the reference value for the grid voltage amplitude of the photovoltaic power generation unit. This represents the voltage droop factor of the DC / AC module. This indicates the reactive power output of photovoltaic power generation; The output phase control is achieved based on the following control equation:

[0018] In the formula, Indicates the output phase of the photovoltaic power generation unit. This represents the phase compensation coefficient of the DC / AC module; ultimately, it enables the regulation of the output frequency, voltage, and phase of the photovoltaic power generation unit.

[0019] Furthermore, an AC droop control method incorporating a phase control mechanism is employed to control the AC / DC module on the hydrogen side, specifically including: The output frequency control is achieved based on the following control equation:

[0020] In the formula, This represents the actual output frequency of the electrolysis hydrogen production unit. This indicates the reference value for the output frequency of the electrolysis hydrogen production unit. This represents the frequency droop factor of the AC / DC module. Indicates the active power input to the electrolytic cell. This represents the frequency compensation coefficient of the AC / DC module. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This indicates the reference value for the intermediate stage DC voltage in hydrogen electrolysis production; The output voltage control is achieved based on the following control equation:

[0021] In the formula, This represents the actual value of the grid voltage amplitude of the electrolytic hydrogen production unit. This indicates a reference value for the grid voltage amplitude of the electrolysis hydrogen production unit. This represents the voltage droop factor of the AC / DC module. This indicates the reactive power output of the electrolysis hydrogen production unit; The output phase control is achieved based on the following control equation:

[0022] In the formula, This indicates the output phase of the electrolytic hydrogen production unit. This represents the phase compensation coefficient of the AC / DC module; ultimately, it enables the regulation of the output frequency, voltage, and phase of the electrolytic hydrogen production unit.

[0023] Compared with the prior art, the beneficial effects of the present invention are: (1) Unlike the traditional solution of storing excess photovoltaic power generation energy in chemical batteries, this invention uses the photovoltaic side and hydrogen side to control the photovoltaic side and directly use the excess photovoltaic power generation energy for electrolysis to produce hydrogen. This not only improves the new energy consumption rate, but also avoids many problems of photovoltaic grid connection from the root. It solves the problem of bidirectional collaborative adaptive grid 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 built-in MPPT algorithm and voltage threshold control). The hydrogen side forms an electrolysis cell load through the AC / DC module and the DC / DC module (also with voltage threshold control). The system adopts the bilateral collaborative adaptive grid construction control method described in this invention to realize electrical interconnection and energy interaction through the AC bus, ensuring dynamic power balance between photovoltaic output and electrolysis load, and establishing a stable AC bus voltage.

[0024] (2) This invention achieves dynamic power balance between photovoltaic output and electrolytic hydrogen production. It can quickly respond by adjusting frequency, voltage and phase when photovoltaic output suddenly increases or decreases, ensuring the stable operation of the overall system. The introduction of the AC bus not only enhances the interconnection capability of the system, but also enables bidirectional regulation and backup between the source and load. The photovoltaic-hydrogen bilateral collaborative grid control designed in this invention can actively build AC bus voltage and achieve grid operation without relying on external power grid or energy storage under the condition of light, ensuring the stability of system voltage. The phase control introduced significantly improves the response speed of the photovoltaic-hydrogen DC / AC module and AC / DC module output, so as to achieve the goal of dynamic power balance of photovoltaic output under environmental changes. Attached Figure Description

[0025] Figure 1 This is a topology diagram of the photo-hydrogen bilateral coupling system of the present invention; Figure 2 This is a topology diagram of the photovoltaic power generation unit of the present invention; Figure 3 This is a schematic diagram of the control strategy of the DC / DC module on the photovoltaic side of the present invention; Figure 4 This is a schematic diagram of the control strategy of the DC / AC module on the photovoltaic side of the present invention; Figure 5 This is a topological diagram of the electrolytic hydrogen production unit of the present invention; Figure 6 This is a schematic diagram of the control strategy of the AC / DC module on the hydrogen side of the present invention; Figure 7 This is a schematic diagram of the control strategy of the hydrogen-side DC / DC module of the present invention; Figure 8 This is a schematic diagram illustrating the change in intermediate DC voltage of the photovoltaic power generation unit and the electrolysis hydrogen production unit caused by the increase in photovoltaic irradiance according to the present invention. Figure 9 This is a schematic diagram illustrating the changes in the active power output of photovoltaic power generation on the photovoltaic side and the active power input of the electrolyzer on the hydrogen side caused by the increase in photovoltaic irradiance according to the present invention. Figure 10 This is a schematic diagram illustrating the change in AC voltage (i.e., AC bus voltage) caused by the increase in photovoltaic irradiance according to the present invention. Figure 11 This is a schematic diagram illustrating the change in AC frequency (i.e., AC bus frequency) caused by the increase in photovoltaic irradiance according to the present invention. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0028] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of this invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0029] The present invention will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0030] The photovoltaic-hydrogen bilateral cooperative adaptive grid control method of this invention is applied to a photovoltaic-hydrogen bilateral coupling system. The core of this system lies in achieving flexible interconnection between the photovoltaic power generation unit and the electrolytic hydrogen production unit via an AC bus. The photovoltaic power generation unit and the electrolytic hydrogen production unit are directly connected via the AC bus, forming an independent photovoltaic-hydrogen interconnected system. This system does not rely on communication, enabling the electrolytic hydrogen production unit to flexibly absorb photovoltaic power on-site under fluctuating operating conditions, ensuring real-time power balance between the photovoltaic and hydrogen sides, and jointly constructing a stable AC bus voltage. Simultaneously, the system employs an improved droop control strategy and a phase cooperative adjustment mechanism to ensure stable operation under dynamic power fluctuations. The photovoltaic-hydrogen bilateral cooperative adaptive grid control method achieves AC bus voltage construction and dynamic power balance between photovoltaic and hydrogen.

[0031] like Figure 1 As shown, this photovoltaic-hydrogen bilateral coupling system includes a photovoltaic power generation unit, an electrolysis hydrogen production unit, and an AC bus. The photovoltaic power generation unit and the electrolysis hydrogen production unit are directly connected via the AC bus, specifically through coupling points PCC1 / PCC2. This allows for bidirectional power exchange and balanced scheduling between the photovoltaic and hydrogen sides during dynamic power regulation, ensuring efficient power exchange and balance. The photovoltaic power generation unit employs a two-stage photovoltaic architecture, comprising photovoltaic panels, a DC / DC module, and a DC / AC module. The photovoltaic panels are connected to the DC / AC module via the photovoltaic-side DC / DC module. The electrolysis hydrogen production unit includes an AC / DC module, a DC / DC module, and an electrolyzer. The electrolyzer is connected to the AC / DC module via the hydrogen-side DC / DC module. In this system, the photovoltaic and hydrogen sides not only perform independent power control on the DC side but also achieve direct power interconnection via the AC bus, enabling coordinated operation during system regulation and further improving the overall system's anti-interference capability and dynamic response speed.

[0032] The topology of a photovoltaic power generation unit is as follows Figure 2 As shown, it includes a photovoltaic panel, a DC / DC module, and a DC / AC module. The DC / DC module on the photovoltaic side uses a Buck circuit. The specific Buck circuit and the various components in the DC / AC module, and their connections, are as follows. Figure 2 The diagram shows a Buck circuit and a DC / AC module commonly used in this field, which will not be described in detail here.

[0033] The topology of the electrolytic hydrogen production unit is as follows: Figure 5 As shown, it includes an AC / DC module, a DC / DC module, and an electrolyzer. The DC / DC module on the hydrogen side uses a Buck circuit. The Buck circuit and the various components in the AC / DC module, and their connections, are detailed below. Figure 5 The diagram shows a Buck circuit and an AC / DC module commonly used in this field, which will not be described in detail here.

[0034] It should be noted that both the photovoltaic-side DC / AC module and the hydrogen-side AC / DC module use LCL filters for filtering. The corresponding inductors and capacitors in the DC / AC module are... and Its induced capacitor voltage is The inductors and capacitors corresponding to the AC / DC module are respectively and Its induced capacitor voltage is .

[0035] 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 operates in maximum power point tracking mode, constant power mode, or overvoltage protection mode to maximize energy capture efficiency; using voltage threshold control to control the DC / DC module on the hydrogen side, so that it operates in shutdown protection mode, constant power mode, or full power mode; and using an AC droop control method with phase control mechanism to control the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side, so as to regulate the output frequency, voltage, and phase of the corresponding photovoltaic power generation unit or electrolytic hydrogen production unit, ensuring a dynamic power balance between photovoltaic output and electrolytic load, so that the system can maintain power balance on both sides of photovoltaic and hydrogen when photovoltaic output fluctuates or electrolytic load changes.

[0036] Furthermore, such as Figure 1 As shown, and All of these are outside of the DC / DC module, DC / AC module, and AC / DC module. The intermediate DC voltage is the intermediate stage DC voltage; therefore, the intermediate DC voltage includes the intermediate DC voltage of the photovoltaic power generation unit. and the intermediate DC voltage of the electrolysis hydrogen production unit In this context, 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.

[0037] Furthermore, such as Figure 3As shown, the DC / DC module on the photovoltaic side is controlled using a maximum power point tracking (MPPT) algorithm and voltage threshold control. Specifically, this includes setting a minimum voltage threshold and a safe voltage threshold for the intermediate DC voltage of the photovoltaic power generation unit; real-time detection of the intermediate DC voltage of the photovoltaic power generation unit; and comparison of the intermediate DC voltage with the set minimum and safe voltage thresholds. When the intermediate 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 maximum power point tracking mode, with its output power reference value being the maximum active power output of the photovoltaic power generation unit, thus achieving maximum power point tracking and maximizing the active power output of the photovoltaic power generation unit. When… When the intermediate DC voltage of the photovoltaic (PV) power generation unit is greater than or equal to the minimum voltage threshold but less than or equal to the safe voltage threshold, it automatically switches to constant power mode to limit PV output. This means limiting the output power reference value of the PV-side DC / DC module according to a linear relationship. When the intermediate DC voltage of the PV power generation unit exceeds the safe voltage threshold, it automatically switches to overvoltage protection mode, adjusting the output power reference value of the PV-side DC / DC module to 0. This forcibly suppresses the intermediate DC voltage of the PV power generation unit, ensuring it is less than or equal to the safe voltage threshold, thus guaranteeing the stability of the corresponding intermediate DC voltage, preventing overvoltage, and ensuring safe equipment operation. The PV output voltage is then monitored in real time. With photovoltaic power generation output active power Based on the output power reference value of the photovoltaic-side DC / DC module, the real-time value of the photovoltaic power generation output voltage, and the real-time value of the photovoltaic power generation active power, the MPPT algorithm is used to dynamically adjust the pulse modulation (PWM) signal of the MOSFET S1 in the photovoltaic-side DC / DC module through a PI controller. The duty cycle is used to control the DC / DC module on the photovoltaic side, where... To drive the PWM signal of MOSFET S1 in the Buck circuit of the photovoltaic power generation unit, the operating state of the photovoltaic panel can be adjusted by changing its duty cycle. Specifically, the output power reference value of the DC / DC module on the photovoltaic side is limited according to a linear relationship, and adjusted according to the following formula:

[0038] In the formula, This indicates the reference value for the output power of the DC / DC module on the photovoltaic side. This indicates the maximum active power output of photovoltaic power generation. Indicates the power limitation rate of photovoltaic power generation. This represents the intermediate DC voltage of the photovoltaic power generation unit. This represents the minimum voltage threshold of the intermediate DC voltage of a photovoltaic power generation unit.

[0039] From the above, it can be seen that the control law of the photovoltaic-side DC / DC module can be expressed as:

[0040] 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.

[0041] 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 MOSFET S2 in the Buck circuit of the hydrogen electrolysis unit, its duty cycle can be adjusted to regulate the input power of the electrolyzer and maximize hydrogen production efficiency. Specifically, the output power reference value of the DC / DC module on the hydrogen side is adjusted linearly according to the following formula:

[0042] In the formula, This indicates the reference value for the output power of the DC / DC module on the hydrogen side. This indicates the maximum active power input to the electrolytic cell. Indicates the power limitation rate for hydrogen production via electrolysis. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This represents the start-up voltage threshold of the intermediate stage DC voltage in the electrolysis hydrogen production unit.

[0043] From the above, it can be seen that the control law of the hydrogen-side DC / DC module can be expressed as:

[0044] In the formula, This represents the maximum voltage threshold of the intermediate stage DC voltage in the hydrogen electrolysis unit. The voltage is then adjusted using a traditional current-controlled DC / DC module control strategy. The duty cycle is adjusted to control the active power input to the electrolyzer and maximize hydrogen production efficiency.

[0045] Furthermore, such as Figure 4 As shown, an AC droop control method incorporating a phase control mechanism is used to control the DC / AC module on the photovoltaic side. Specifically, this includes: ① In output frequency control, the following control equation is used:

[0046] In the formula, This represents the actual output frequency of the photovoltaic power generation unit. This indicates the reference value for the output frequency of the photovoltaic power generation unit. This represents the frequency droop factor of the DC / AC module. Indicates the active power output of photovoltaic power generation. This represents the frequency compensation coefficient of the DC / AC module. This represents the intermediate DC voltage of the photovoltaic power generation unit. This indicates the reference value for the intermediate DC voltage of the photovoltaic power generation unit.

[0047] ② The output voltage control is achieved based on the following control equation:

[0048] In the formula, This represents the actual value of the grid voltage amplitude of the photovoltaic power generation unit. This indicates the reference value for the grid voltage amplitude of the photovoltaic power generation unit. This represents the voltage droop factor of the DC / AC module. This represents the reactive power output of photovoltaic power generation.

[0049] ③ Output phase control is achieved based on the following control equations:

[0050] In the formula, Indicates the output phase of the photovoltaic power generation unit. This represents the phase compensation coefficient of the DC / AC module. Ultimately, it enables the regulation of the output frequency, voltage, and phase of the photovoltaic power generation unit, ensuring a dynamic power balance between photovoltaic output and electrolysis load. This allows the system to maintain power balance on both the photovoltaic and hydrogen sides even when photovoltaic output fluctuates or electrolysis load changes.

[0051] Specifically, the photovoltaic-side DC / AC module employs an AC droop control method incorporating a phase control mechanism; that is, it uses AC droop control, while the power outer loop uses droop control with added phase control. For output frequency control, the system frequency is dynamically adjusted by introducing power deviations based on phase. This system achieves power balance between photovoltaic and hydrogen production and accelerates the response speed of the DC / AC module control. 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 continued, with the voltage amplitude linearly related to reactive power. Reactive power regulation is achieved through the corresponding voltage control equation to precisely control the voltage amplitude, effectively mitigating voltage fluctuations. A phase control term is introduced to adjust the output phase of the DC / AC module in real time based on the intermediate-stage DC voltage deviation of the photovoltaic power generation unit, ensuring both accelerated response speed and synchronous operation with the AC bus in grid-connected mode. 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, the inner current loop achieves rapid current tracking, while the outer voltage loop stably corresponds to the intermediate-stage DC voltage. .

[0052] Furthermore, such as Figure 6 As shown, an AC droop control method with phase control mechanism is used to control the AC / DC module on the hydrogen side. Specifically, this includes: ① In terms of output frequency control, the following control equation is used:

[0053] In the formula, This represents the actual output frequency of the electrolysis hydrogen production unit. This indicates the reference value for the output frequency of the electrolysis hydrogen production unit. This represents the frequency droop factor of the AC / DC module. Indicates the active power input to the electrolytic cell. This represents the frequency compensation coefficient of the AC / DC module. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This indicates the reference value for the intermediate stage DC voltage in hydrogen electrolysis.

[0054] ② The output voltage control is achieved based on the following control equation:

[0055] In the formula, This represents the actual value of the grid voltage amplitude of the electrolytic hydrogen production unit. This indicates a reference value for the grid voltage amplitude of the electrolysis hydrogen production unit. This represents the voltage droop factor of the AC / DC module. This indicates the reactive power output of the electrolytic hydrogen production unit.

[0056] ③ Output phase control is achieved based on the following control equations:

[0057] In the formula, This indicates the output phase of the electrolytic hydrogen production unit. This represents the phase compensation coefficient of the AC / DC module. Ultimately, it enables the regulation of the output frequency, voltage, and phase of the electrolytic hydrogen production unit, ensuring a dynamic power balance between photovoltaic output and electrolytic load. This allows the system to maintain power balance on both the photovoltaic and hydrogen sides even when photovoltaic output fluctuates or electrolytic load changes.

[0058] Specifically, the AC / DC module on the hydrogen side also employs an AC droop control method that incorporates a phase control mechanism. For output frequency control, the active power obtained from the traditional frequency droop formula is combined with the system frequency obtained by introducing the phase control mechanism. 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.

[0059] 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 to the upper limit of hydrogen production, it subsequently declined and stabilized; 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 rises and then falls to a stable state.

[0060] Figure 9 The changes in photovoltaic power generation and hydrogen absorption power are used to illustrate the dynamic balance of system power after the increase in photovoltaic irradiance. Figure 10 The three-phase AC voltage diagram from 2s to 2.1s shows that even with increased photovoltaic irradiance, the AC bus voltage remains stable and has a consistent amplitude. Combined with... Figure 10 and Figure 11 The grid control method described in this invention can maintain a stable grid structure even after the photovoltaic irradiance increases. (Summary) Figures 8-11 It can be seen that the grid control method described in this invention has the ability to solve the problems of stable grid construction in photovoltaic-hydrogen coupling systems and dynamic power balance between photovoltaic output and electrolytic hydrogen production.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-hydrogen bilateral cooperative adaptive network control method, characterized in that, This system is applied to a photovoltaic-hydrogen bilateral coupling system, which includes a photovoltaic power generation unit, an electrolysis hydrogen production unit, and an AC bus. The photovoltaic power generation unit and the electrolysis hydrogen production unit are directly connected via the AC bus. The photovoltaic power generation unit includes a photovoltaic panel, a DC / DC module, and a DC / AC module connected in sequence. The electrolysis hydrogen production unit includes an AC / DC module, a DC / DC module, and an electrolyzer connected in sequence. The method specifically includes: using a maximum power point tracking algorithm and voltage threshold control to control the DC / DC module on the photovoltaic side, so that it operates in maximum power point tracking mode, constant power mode, or overvoltage protection mode; using voltage threshold control to control the DC / DC module on the hydrogen side, so that it operates in shutdown protection mode, constant power mode, or full power mode; and using an AC droop control method with phase control mechanism to control the DC / AC module on the photovoltaic side or the AC / DC module on the hydrogen side, so as to regulate the output frequency, voltage, and phase of the corresponding photovoltaic power generation unit or electrolysis hydrogen production unit, and ensure that a dynamic power balance is formed between photovoltaic output and electrolysis load.

2. The light-hydrogen bilateral cooperative adaptive network control method according to claim 1, characterized in that, The method of controlling the photovoltaic-side DC / DC module using the maximum power point tracking algorithm and voltage threshold control specifically includes: A minimum voltage threshold and a safe voltage threshold are set for the intermediate DC voltage of the photovoltaic (PV) power generation unit. The intermediate DC voltage of the PV power generation unit is detected in real time and compared with the set minimum voltage threshold and safe voltage threshold. When the intermediate DC voltage of the PV power generation unit is less than the minimum voltage threshold, the DC / DC module on the PV side operates in maximum power point tracking mode, and its output power reference value is the maximum active power output of the PV power generation unit. When the intermediate DC voltage of the PV power generation unit is greater than or equal to the minimum voltage threshold and less than or equal to the safe voltage threshold, it automatically switches to constant power mode and limits the output power reference value of the DC / DC module on the PV side according to a linear relationship. When the intermediate DC voltage of the PV power generation unit is greater than the safe voltage threshold, it automatically switches to overvoltage protection mode and adjusts the output power reference value of the DC / DC module on the PV side to 0 to forcibly suppress the intermediate DC voltage of the PV power generation unit. Based on the output power reference value of the photovoltaic-side DC / DC module, the real-time output voltage value of photovoltaic power generation, and the real-time output active power value of photovoltaic power generation, the maximum power point tracking algorithm is used to dynamically adjust the duty cycle of the pulse modulation signal of MOSFET S1 in the photovoltaic-side DC / DC module through a PI controller, thereby realizing the control of the photovoltaic-side DC / DC module.

3. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 2, characterized in that, 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.

4. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 2, characterized in that, The reference value for limiting the output power of the photovoltaic-side DC / DC module according to a linear relationship is adjusted specifically according to the following formula: ； In the formula, This indicates the reference value for the output power of the DC / DC module on the photovoltaic side. This indicates the maximum active power output of photovoltaic power generation. This represents the linearity coefficient on the photovoltaic side. This represents the intermediate DC voltage of the photovoltaic power generation unit. This represents the minimum voltage threshold of the intermediate DC voltage of a photovoltaic power generation unit.

5. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 1, characterized in that, The control of the hydrogen-side DC / DC module using voltage threshold control specifically includes: A start-up voltage threshold and a maximum voltage threshold are set for the intermediate stage DC voltage of the hydrogen electrolysis unit. The intermediate stage DC voltage of the hydrogen electrolysis unit is monitored in real time and compared 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 DC / DC module on the hydrogen side operates 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 stage DC voltage of the hydrogen electrolysis unit is greater than or equal to the start-up voltage threshold and less than or equal to the maximum voltage threshold, it automatically switches to 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 stage DC voltage of the hydrogen electrolysis unit is greater than the maximum voltage threshold, it automatically switches to 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 electrolyzer. Based on the reference value of the output power of the DC / DC module on the hydrogen side and the real-time value of the active power input to the electrolyzer, the duty cycle of the pulse modulation signal of the MOS transistor S2 in the DC / DC module on the hydrogen side is dynamically adjusted by the PI controller to achieve control of the DC / DC module on the hydrogen side.

6. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 5, characterized in that, 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.

7. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 5, characterized in that, The reference value for adjusting the output power of the hydrogen-side DC / DC module according to a linear relationship is specifically adjusted based on the following formula: ； In the formula, This indicates the reference value for the output power of the DC / DC module on the hydrogen side. This indicates the maximum active power input to the electrolytic cell. This indicates the power limitation rate for hydrogen production via electrolysis. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This represents the start-up voltage threshold of the intermediate stage DC voltage in the electrolysis hydrogen production unit.

8. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 1, characterized in that, An AC droop control method incorporating a phase control mechanism is used to control the DC / AC module on the photovoltaic side, specifically including: The output frequency control is achieved based on the following control equation: ； In the formula, This represents the actual output frequency of the photovoltaic power generation unit. This indicates the reference value for the output frequency of the photovoltaic power generation unit. This represents the frequency droop factor of the DC / AC module. Indicates the active power output of photovoltaic power generation. This represents the frequency compensation coefficient of the DC / AC module. This represents the intermediate DC voltage of the photovoltaic power generation unit. This indicates the reference value for the intermediate stage DC voltage of the photovoltaic power generation unit; The output voltage control is achieved based on the following control equation: ； In the formula, This represents the actual value of the grid voltage amplitude of the photovoltaic power generation unit. This indicates the reference value for the grid voltage amplitude of the photovoltaic power generation unit. This represents the voltage droop factor of the DC / AC module. This represents the reactive power output of photovoltaic power generation; The output phase control is achieved based on the following control equation: ； In the formula, Indicates the output phase of the photovoltaic power generation unit. This represents the phase compensation coefficient of the DC / AC module; ultimately, it enables the regulation of the output frequency, voltage, and phase of the photovoltaic power generation unit.

9. The photo-hydrogen bilateral cooperative adaptive network control method according to claim 1, characterized in that, An AC droop control method incorporating a phase control mechanism is used to control the AC / DC module on the hydrogen side, specifically including: The output frequency control is achieved based on the following control equation: ； In the formula, This represents the actual output frequency of the electrolysis hydrogen production unit. This indicates the reference value for the output frequency of the electrolysis hydrogen production unit. This represents the frequency droop factor of the AC / DC module. Indicates the input active power of the electrolytic cell. This represents the frequency compensation coefficient of the AC / DC module. This represents the intermediate stage DC voltage of the electrolytic hydrogen production unit. This indicates the reference value for the intermediate stage DC voltage in hydrogen electrolysis production; The output voltage control is achieved based on the following control equation: ； In the formula, This represents the actual value of the grid voltage amplitude of the electrolytic hydrogen production unit. This indicates a reference value for the grid voltage amplitude of the electrolysis hydrogen production unit. This represents the voltage droop factor of the AC / DC module. This indicates the reactive power output of the electrolysis hydrogen production unit; The output phase control is achieved based on the following control equation: ； In the formula, This indicates the output phase of the electrolytic hydrogen production unit. This represents the phase compensation coefficient of the AC / DC module; ultimately, it enables the regulation of the output frequency, voltage, and phase of the electrolytic hydrogen production unit.

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