New energy electrolytic hydrogen generator rectifier with off-grid adaptability and control method

Abstract

The application discloses a new energy electrolytic hydrogen production rectifier with off-grid adaptability and a control method, and the rectifier comprises an inverter with droop control, a transformer, a non-controlled rectifier, a DC / DC converter and a controller, can adapt to new energy fluctuation power supply environment, and supports off-grid operation.The control method comprises the following steps: S1, rectifying alternating current and inputting to the DC / DC converter; S2, collecting a real-time frequency value and calculating a frequency deviation value; S3, generating a direct current instruction value; S4, collecting an actual output current value; S5, generating a PWM control signal and adjusting the output current; and S6, realizing speed regulation of the output power of the non-controlled rectifier.The application can achieve the function of assisting in stabilizing the frequency of an off-grid micro-grid, can adapt to the working condition of off-grid new energy electrolytic hydrogen production in the scene of off-grid new energy electrolytic hydrogen production, and enables the hydrogen production load end to follow the high fluctuation of new energy power generation, and simultaneously assists in stabilizing the frequency of the off-grid system.

Description

Technical Field

[0001] This invention relates to the field of rectifier control technology, and in particular to a new energy electrolysis hydrogen production rectifier and control method with off-grid adaptability. Background Technology

[0002] Hydrogen energy, as a zero-carbon green renewable energy source, has advantages such as high energy density and high conversion efficiency, and can achieve zero emissions and zero pollution throughout the entire process from development to utilization. Hydrogen production is an important link in the hydrogen energy industry chain. Existing hydrogen production technologies mainly include hydrogen production from fossil fuels and chemical by-products, biomass hydrogen production, and water electrolysis hydrogen production. Compared with other hydrogen production methods, water electrolysis hydrogen production has advantages such as near-zero emissions and high hydrogen purity. Furthermore, it can be combined with photovoltaic and wind power renewable energy generation to effectively absorb unstable energy sources such as wind and photovoltaic power, mitigate the impact of their fluctuations on the power grid, and has significant economic and social benefits.

[0003] As the core device for hydrogen production through water electrolysis, the performance of the rectifier power supply directly affects the efficiency and cost of hydrogen production. The direct current output from the hydrogen production energy source is used for electrolysis, and it must meet the requirements of low-voltage, high-current output, high reliability, and high efficiency. Currently, industrial high-power electrolysis hydrogen production thyristor rectifiers typically use an on-load tap-changing transformer (OTCT) as the front-end. OOTCTs have multiple adjustment ranges, allowing voltage level adjustments under load. The output power of the thyristor rectifier is adjusted by changing the transformer range and the firing angle of the thyristor rectifier. However, OOTCT range adjustment is achieved by switching mechanical switches, which takes a long time. When using fluctuating renewable energy sources such as wind and solar power to supply the rectifier power supply, the output voltage (current) of the rectifier power supply needs to be adjusted according to changes in renewable energy power generation to regulate the electrolysis hydrogen production power. However, using an OOTCT transformer results in a slow dynamic response, making it impossible to keep up with the power generation of renewable energy sources. Furthermore, the stability of the AC bus frequency is also an extremely important factor in off-grid conditions. New energy electrolysis hydrogen production rectifiers with off-grid operating capabilities can adjust power at a relatively fast speed, thus they can better stabilize the frequency of the AC bus in off-grid microgrids.

[0004] To achieve rapid adjustment of the rectifier power output, one method proposes using a fixed-ratio transformer, adjusting the rectifier output power solely by regulating the firing angle of the thyristor rectifier. While this method can achieve rapid power adjustment, a large firing angle can worsen the grid-connected current harmonics and power factor, making it unsuitable for grid connection. Furthermore, in off-grid microgrid conditions, the frequency stability of the AC bus is difficult to guarantee due to the inability to rapidly control and adjust the power output; frequency instability could even lead to the collapse of the off-grid microgrid. Therefore, rectifier control methods also need to be addressed. This paper proposes a rectifier and control method to adapt to off-grid environments and offer better control flexibility. Traditional thyristor rectifiers primarily control DC output voltage and current by adjusting the firing angle, resulting in low control flexibility. Simultaneously, this rectifier can achieve precise control of the output DC current, reducing DC current ripple and improving the hydrogen production efficiency of the electrolysis stack. Summary of the Invention

[0005] The purpose of this invention is to provide a new energy electrolysis hydrogen production rectifier and control method with off-grid adaptability. It solves the problem of slow dynamic response speed caused by the current on-load transformer with thyristor power supply, which cannot quickly follow the power fluctuation of renewable energy. At the same time, when in the off-grid operation of microgrids for new energy power generation such as wind and solar, it can also effectively solve the problem of bus frequency fluctuation in off-grid microgrids by coupling the AC side frequency with the DC / DC output current through droop control.

[0006] A new energy electrolysis hydrogen production rectifier with off-grid adaptability according to an embodiment of the present invention includes:

[0007] An inverter with droop control, whose output is connected to the AC bus, is used to provide AC power output under simulated off-grid conditions.

[0008] The transformer has its input end connected to the AC bus to achieve voltage transformation, and its low-voltage output end is connected to the input end of an uncontrolled rectifier.

[0009] An uncontrolled rectifier has its input terminal connected to the low-voltage output terminal of a transformer and its output terminal connected to the input terminal of a DC / DC converter. It is used to rectify AC power into DC power.

[0010] The DC / DC converter has its input terminal connected to the output terminal of an uncontrolled rectifier and its output terminal connected to an electrolytic cell to provide adjustable DC power to the electrolytic cell.

[0011] The controller is connected to both the inverter with droop control and the DC / DC converter. It is used to collect the frequency information of the AC bus in real time, generate current control commands according to the droop control method, and output PWM control signals to the DC / DC converter.

[0012] Optionally, the uncontrolled rectifier is a diode rectifier, and the DC / DC converter uses a buck circuit to achieve the DC / DC converter voltage reduction effect;

[0013] The new energy electrolysis hydrogen production control method with off-grid adaptability according to an embodiment of the present invention includes the following steps:

[0014] S1. The AC power output from the transformer is rectified by an uncontrolled rectifier to obtain a DC voltage input to the DC / DC converter.

[0015] S2. Collect the real-time frequency value of the AC bus on the output side of the inverter with droop control, and calculate the frequency deviation value.

[0016] S3. Generate a DC current command value based on the frequency deviation value to indicate the target output current of the DC / DC converter;

[0017] S4. Collect the current actual output current value of the DC / DC converter and input the actual output current value and DC current command value to the controller;

[0018] S5. The controller calculates and generates a PWM control signal, which is then sent to the DC / DC converter to adjust the output current.

[0019] S6. Based on the adjustment results of the DC / DC converter output current, the speed regulation of the output power of the uncontrolled rectifier is realized, and the real-time response and balance adjustment of the electrolytic hydrogen production load to the frequency change of the new energy AC bus is completed.

[0020] Optionally, S2 specifically includes:

[0021] S21. Acquire AC bus signal from the output terminal of the inverter with droop control, and extract the real-time frequency value f of the AC bus through a phase-locked loop;

[0022] S22. Input the real-time frequency value f into the frequency processing module of the controller, and compare it with the preset frequency reference value f. ref Perform the difference operation to obtain the frequency deviation value Δf.

[0023] Optionally, S3 specifically includes:

[0024] S31. Input the frequency deviation value Δf into the current command generation module in the controller;

[0025] S32. In the current command generation module, set the rated output current of the DC / DC converter to I0 and set the droop control coefficient to k. droop ;

[0026] S33. Based on the frequency deviation value Δf, the rated output current I0, and the droop control coefficient k droop Calculate the DC current command value I ref :

[0027]

[0028] S34, Set DC current command value I ref The current control module output to the controller indicates the target output current of the DC / DC converter.

[0029] Optionally, S4 specifically includes:

[0030] S41. Acquire the current actual output current value I of the DC / DC converter and measure it in real time through the controller connected to the current sampling circuit;

[0031] S42. Compare the actual output current value I with the DC current command value I. ref The current control module is input together with the controller;

[0032] S43. In the current control module of the controller, the actual output current value I and the DC current command value I are compared. ref Perform the difference calculation to obtain the current error signal ΔI;

[0033] S44. Input the current error signal ΔI to the PI controller and PR controller of the PWM control signal generation module to drive the output process of the PWM control signal.

[0034] Optionally, S5 specifically includes:

[0035] S51. In the PWM control signal generation module, based on the current error signal ΔI, set the PWM modulation parameters, including the switching frequency f. down The adjustment range of the duty cycle D;

[0036] S52. Based on ΔI and PWM modulation parameters, generate a PWM control signal sequence for driving the DC / DC converter through modulation calculation;

[0037] S53. Send the PWM control signal sequence to the power drive unit of the DC / DC converter, adjust the actual current value output by the converter, and apply the target current to the electrolytic cell.

[0038] Optionally, S6 specifically includes:

[0039] S61. Acquire the output current value of the DC / DC converter after being driven by the PWM signal, and determine whether it has approached the current command value I. ref ;

[0040] S62, When the output current value is the same as the DC current command value I ref When the error between the two is lower than the set threshold ε, the DC / DC converter is determined to have reached a stable output state.

[0041] S63. Using the actual current value under stable output conditions as the basis for the current output power of the uncontrolled rectifier, the current actual output power P is calculated through the uncontrolled rectifier power feedback module. out ;

[0042] S64, the actual output power P out Feedback is sent to the inverter droop control logic to adjust the AC bus frequency in a coordinated manner, thereby forming a real-time adaptive droop balance between the uncontrolled rectifier load power and the renewable energy power supply frequency.

[0043] The beneficial effects of this invention are:

[0044] The aforementioned off-grid adaptable new energy electrolysis hydrogen production rectifier and control method simulates the scenario of renewable energy power supply by using an inverter with droop control at the front end and a DC / DC converter at the back end, thereby enabling rapid changes in the power of the electrolyzer. When the power generation of electrolysis hydrogen production becomes unstable, it is necessary to quickly adjust the electrolysis hydrogen production power to follow the fluctuations in the power generation of new energy. At the same time, the frequency stability of the off-grid microgrid of new energy with droop control also relies on rapid power changes.

[0045] Compared to traditional thyristor rectifiers in on-load tap-changing transformers, this invention can rapidly change the voltage level by controlling the output of the DC / DC converter, thereby achieving rapid changes in the power of the electrolyzer. It enables the use of renewable energy sources such as wind and solar power as a power source, and when their power generation becomes unstable, it can quickly adjust the electrolysis hydrogen production power to follow the fluctuations in renewable energy power generation. Furthermore, it can help stabilize the AC bus frequency when the frequency of the off-grid microgrid AC bus is unstable. Thyristor rectifiers, which typically require on-load tap-changing switches in transformers for adjustment, have relatively slow dynamic response speeds, which may lead to system instability when renewable energy power fluctuates significantly.

[0046] This rectifier is adaptable to off-grid operating conditions and various adjustment requirements, offering greater control flexibility. It significantly reduces the time required for voltage level changes, accelerates the matching of the electrolyzer with renewable energy power generation, and provides excellent support for the AC bus frequency. Traditional thyristor rectifiers primarily control DC output voltage and current by adjusting the firing angle, resulting in lower control flexibility. Simultaneously, this rectifier enables precise control of the output DC current, reducing DC current ripple and improving the hydrogen production efficiency of the electrolysis stack. In off-grid renewable energy electrolysis hydrogen production scenarios, it adapts to the operating conditions, allowing the hydrogen production load to follow the high volatility of renewable energy generation, while also helping to stabilize the off-grid system frequency. Attached Figure Description

[0047] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 This is a circuit topology block diagram of the new energy electrolysis hydrogen production rectifier with off-grid adaptability proposed in this invention;

[0049] Figure 2 This is an overall flowchart of the new energy electrolysis hydrogen production control method with off-grid adaptability proposed in this invention. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0051] refer to Figure 1 A circuit topology block diagram of a new energy electrolysis hydrogen production rectifier with off-grid adaptability, including:

[0052] An inverter with droop control, whose output is connected to the AC bus, is used to provide AC power output under simulated off-grid conditions.

[0053] The transformer has its input end connected to the AC bus to achieve voltage transformation, and its low-voltage output end is connected to the input end of an uncontrolled rectifier.

[0054] An uncontrolled rectifier has its input terminal connected to the low-voltage output terminal of a transformer and its output terminal connected to the input terminal of a DC / DC converter. It is used to rectify AC power into DC power.

[0055] The DC / DC converter has its input terminal connected to the output terminal of an uncontrolled rectifier and its output terminal connected to an electrolytic cell to provide adjustable DC power to the electrolytic cell.

[0056] The controller is connected to both the inverter with droop control and the DC / DC converter. It is used to collect the frequency information of the AC bus in real time, generate current control commands according to the droop control method, and output PWM control signals to the DC / DC converter.

[0057] The off-grid adaptable new energy electrolysis hydrogen production rectifier provided by this invention allows for flexible selection of the DC / DC converter when the upstream stage is an inverter with droop control. A buck circuit can be used to perform DC voltage reduction. Adding droop control to the rectifier when using the above equipment enables rapid power adjustment and simultaneously helps stabilize the frequency of the new energy AC bus.

[0058] The new energy electrolysis hydrogen production rectifier of the present invention links the frequency of the AC bus with the current at the load end of the new energy electrolysis hydrogen production rectifier by adopting the control logic shown in the figure, and designs a droop relationship equation between the change value of the AC bus frequency and the command value of the current, thereby realizing the purpose of controlling the command value of the current at the load end of the new energy electrolysis hydrogen production rectifier by detecting the real-time AC bus frequency value.

[0059] It should be noted that in this embodiment, the AC bus frequency of the inverter with droop control can be acquired using a phase-locked loop (PLL). The actual frequency value is compared with a pre-set frequency reference value, and the difference is used to obtain the real-time current command value after control via the droop relationship equation. This achieves the control link between the AC bus frequency and the downstream rectifier. By adopting the principle of droop control to link the AC bus frequency with the output current of the DC / DC converter, and by using the droop relationship to list the change value of the AC bus frequency and the command value of the DC / DC converter's output current, the real-time frequency value of the AC bus can be detected to control the output current command value of the DC / DC converter. After obtaining the current command value, the current command value and the acquired real-time current are processed by a PI and PR controller to generate a PWM wave that provides a control signal to the DC / DC converter, thereby achieving output current control of the DC / DC converter and realizing the control link between the AC bus frequency and the downstream rectifier. This ensures droop balance between the AC bus frequency of the new energy source and the load power.

[0060] When encountering sudden changes in the power output of new energy generation, the rectifier will quickly adjust its power according to the control method of this invention. After the output power of the electrolytic hydrogen production rectifier is regulated, under the action of rectifier droop control, the real-time current value and current command value return to stability, and the droop relationship between the load current and the AC bus frequency also reaches a new stability. At the same time, due to the inverter's droop relationship, after the power consumption of the downstream rectifier load decreases, the AC bus frequency is also effectively restored and reaches a new stability.

[0061] refer to Figure 2 A new energy electrolysis hydrogen production control method with off-grid adaptability includes the following steps:

[0062] S1. The AC power output from the transformer is rectified by an uncontrolled rectifier to obtain a DC voltage input to the DC / DC converter.

[0063] S2. Collect the real-time frequency value of the AC bus on the output side of the inverter with droop control, and calculate the frequency deviation value.

[0064] S3. Generate a DC current command value based on the frequency deviation value to indicate the target output current of the DC / DC converter;

[0065] S4. Collect the current actual output current value of the DC / DC converter and input the actual output current value and DC current command value to the controller;

[0066] S5. The controller calculates and generates a PWM control signal, which is then sent to the DC / DC converter to adjust the output current.

[0067] S6. Based on the adjustment results of the DC / DC converter output current, the speed regulation of the output power of the uncontrolled rectifier is realized, and the real-time response and balance adjustment of the electrolytic hydrogen production load to the frequency change of the new energy AC bus is completed.

[0068] In this embodiment, S2 specifically includes:

[0069] S21. Acquire AC bus signal from the output terminal of the inverter with droop control, and extract the real-time frequency value f of the AC bus through a phase-locked loop;

[0070] S22. Input the real-time frequency value f into the frequency processing module of the controller, and compare it with the preset frequency reference value f. ref Perform the difference operation to obtain the frequency deviation value Δf.

[0071] In this embodiment, S3 specifically includes:

[0072] S31. Input the frequency deviation value Δf into the current command generation module in the controller;

[0073] S32. In the current command generation module, set the rated output current of the DC / DC converter to I0 and set the droop control coefficient to k. droop ;

[0074] S33. Based on the frequency deviation value Δf, the rated output current I0, and the droop control coefficient k droop Calculate the DC current command value I ref :

[0075]

[0076] S34, Set DC current command value I ref The current control module output to the controller indicates the target output current of the DC / DC converter.

[0077] In this embodiment, S4 specifically includes:

[0078] S41. Acquire the current actual output current value I of the DC / DC converter and measure it in real time through the controller connected to the current sampling circuit;

[0079] S42. Compare the actual output current value I with the DC current command value I. ref The current control module is input together with the controller;

[0080] S43. In the current control module of the controller, the actual output current value I and the DC current command value I are compared. ref Perform the difference calculation to obtain the current error signal ΔI;

[0081] S44. Input the current error signal ΔI to the PI controller and PR controller of the PWM control signal generation module to drive the output process of the PWM control signal.

[0082] In this embodiment, S5 specifically includes:

[0083] S51. In the PWM control signal generation module, based on the current error signal ΔI, set the PWM modulation parameters, including the switching frequency f. down The adjustment range of the duty cycle D;

[0084] S52. Based on ΔI and PWM modulation parameters, generate a PWM control signal sequence for driving the DC / DC converter through modulation calculation;

[0085] S53. Send the PWM control signal sequence to the power drive unit of the DC / DC converter, adjust the actual current value output by the converter, and apply the target current to the electrolytic cell.

[0086] In this embodiment, S6 specifically includes:

[0087] S61. Acquire the output current value of the DC / DC converter after being driven by the PWM signal, and determine whether it has approached the current command value I. ref ;

[0088] S62, When the output current value is the same as the DC current command value I ref When the error between the two is lower than the set threshold ε, the DC / DC converter is determined to have reached a stable output state.

[0089] S63. Using the actual current value under stable output conditions as the basis for the current output power of the uncontrolled rectifier, the current actual output power P is calculated through the uncontrolled rectifier power feedback module. out ;

[0090] S64, the actual output power P out Feedback is sent to the inverter droop control logic to adjust the AC bus frequency in a coordinated manner, thereby forming a real-time adaptive droop balance between the uncontrolled rectifier load power and the renewable energy power supply frequency.

[0091] In this invention, by using an inverter with droop control in the front stage, a diode rectifier in the middle stage, and a DC / DC converter in the rear stage, the voltage level can be quickly changed by controlling the output of the DC / DC converter, thereby achieving rapid changes in the power of the electrolyzer. It enables the use of renewable energy sources such as wind and solar power as power sources, and when their power generation becomes unstable, it quickly adjusts the electrolysis hydrogen production power to follow the fluctuations in renewable energy power generation. Furthermore, it helps stabilize the AC bus frequency when the off-grid microgrid AC bus frequency is unstable. Thyristor rectifiers, which typically require on-load tap changers to adjust, have relatively slow dynamic response speeds, which may lead to instability in the system when renewable energy power fluctuates significantly. This rectifier can adapt to off-grid environments, has better control flexibility, greatly reduces the time required to change voltage levels, accelerates the matching of the electrolyzer to renewable energy power generation, and provides good support for the AC bus frequency. Traditional thyristor rectifiers mainly control the DC output voltage and current by adjusting the firing angle, resulting in lower control flexibility. Meanwhile, this rectifier can achieve precise control of the output DC current, reduce the ripple component of the DC current, and improve the hydrogen production efficiency of the electrolysis stack. In off-grid renewable energy electrolysis hydrogen production scenarios, it can adapt to the operating conditions of off-grid renewable energy electrolysis hydrogen production, allowing the hydrogen production load to follow the high volatility of renewable energy power generation, while also helping to stabilize the frequency of the off-grid system.

[0092] Example 1:

[0093] To verify the feasibility of this invention in practice, it was applied to a new energy off-grid demonstration hydrogen production station in a certain region. This station is powered by an unstable renewable energy source provided by a wind farm (30MW installed capacity) and a photovoltaic array (20MW installed capacity) to drive an electrolyzer for hydrogen production. Due to the region's perennial influence from the Northwest Plateau climate, wind speeds fluctuate frequently, and sunlight conditions are significantly affected by rapid cloud cover changes, resulting in large power frequency fluctuations and poor load response. Therefore, traditional thyristor rectifiers operating with transformer voltage regulation suffer from problems such as frequency instability, lag in current response, and low electrolysis efficiency.

[0094] In this embodiment, the new energy electrolysis hydrogen production rectifier with off-grid adaptability described in this invention is adopted, comprising a droop-controlled inverter, a transformer, an uncontrolled rectifier, a Buck-type DC / DC converter, and a controller. The rectifier upstream provides a constant DC bus voltage using uncontrolled diode rectification. The controller collects the AC bus frequency output by the inverter in real time, calculates the frequency deviation using a droop control algorithm, and then dynamically generates a current command value based on the deviation to drive the DC / DC converter to output a precise DC current. This allows the electrolyzer load to dynamically track renewable energy power fluctuations, achieving supply-demand matching.

[0095] During continuous operation testing, we selected daily load curves under typical off-grid operating conditions such as "strong wind-weak light", "weak wind-strong light", and "night-weak wind" for comparative testing, and recorded the following key indicators: rectifier response time, electrolyzer current ripple, electrolysis hydrogen production efficiency, electrolysis current deviation (error from command value), and bus frequency fluctuation range.

[0096] By collecting control system logs and hydrogen flow meter data, we compared our invention with traditional thyristor rectification solutions and found that it has significant advantages in several key performance aspects.

[0097] Table 1: Performance Comparison Table of the Invention System and Traditional Thyristor Rectifier Systems

[0098]

[0099]

[0100] As can be clearly seen from the measured data of the off-grid hydrogen production station of new energy shown in Table 1 above, the control system proposed in this invention is significantly better than the traditional thyristor rectification scheme in many key operating indicators, and exhibits good stability, dynamic response capability and system robustness.

[0101] Taking load response time as an example, traditional systems have an average response time of over 13 seconds under sudden wind speed changes, with some extreme cases reaching 17.2 seconds. The system of this invention, however, reduces this value to less than 3.6 seconds, improving response speed by nearly 80%. Especially in unstable grid scenarios such as sudden drops in wind speed at night, traditional systems often suffer from frequency collapse or system protective shutdown due to adjustment lag. This system, relying on a frequency-current closed-loop mechanism, can complete adaptive adjustment within 4.1 seconds, ensuring safe and continuous system operation.

[0102] Regarding the current ripple factor, this system controls the output DC current ripple to within 4% in all test scenarios, which is more than 50% lower than the traditional solution on average. This significantly reduces the loss of the electrolytic stack, extends the system life, and reduces the frequency of operation and maintenance.

[0103] In terms of electrolysis efficiency, traditional systems are limited by frequent voltage fluctuations and slow adjustments. During periods of photovoltaic disturbance or drastic wind speed changes, the efficiency is mostly maintained between 81% and 83%. However, this system maintains a stable efficiency of over 88% through dynamic command value control and PWM fine-tuning strategy. In particular, the peak efficiency measured under special scenarios is as high as 89.1%, demonstrating excellent energy utilization capabilities.

[0104] In addition, the frequency fluctuation range of the bus in traditional systems generally exceeds ±1.5Hz, and even exceeds 3Hz in extreme environments, which can easily trigger microgrid interlocking protection. However, the system of this invention is controlled within ±0.7Hz throughout the entire operation process, with a maximum deviation of only 1.2Hz, proving that it has a high frequency self-stabilization capability and can adapt to complex off-grid operation environments.

[0105] Regarding current error, specifically the deviation between the actual output current and the commanded value, this system maintains a deviation within ±3% in most scenarios, while traditional systems often exhibit errors exceeding 5-7%, demonstrating significant hysteresis. This is particularly evident under refined hydrogen production load conditions, where this system effectively controls I... ref The tracking capability ensures the uniformity of hydrogen production and the continuity of the process.

[0106] In summary, the control strategy verified in this embodiment, under the condition of multi-source renewable energy access, not only solves the problems of slow response, large current fluctuation and lack of frequency control of traditional rectifiers by establishing a closed-loop control chain of frequency sampling-current command-error compensation-PWM regulation-frequency feedback, but also enables the hydrogen production system to maintain efficient, safe and stable operation in extreme environments with severe grid frequency fluctuations and frequent alternation of light / wind speed.

[0107] This embodiment verifies the high adaptability and engineering application potential of the present invention in off-grid electrolysis hydrogen production scenarios. The proposed system architecture and control method are particularly suitable for wind-solar hybrid hydrogen production scenarios, remote independent grid areas, and hydrogen production facilities under extreme climates, providing solid technical support for building a highly reliable and efficient clean hydrogen energy supply system.

[0108] The above description is merely a preferred embodiment of the present invention and does not constitute a limitation on the scope of protection of the present invention. Any equivalent transformations and improvements made by those skilled in the art based on the disclosure of the present invention should fall within the scope of protection of the present invention.

Claims

1. A new energy electrolysis hydrogen production rectifier with off-grid adaptability, characterized in that, include: An inverter with droop control, whose output is connected to the AC bus, is used to provide AC power output under simulated off-grid conditions. The transformer has its input end connected to the AC bus to achieve voltage transformation, and its low-voltage output end is connected to the input end of an uncontrolled rectifier. An uncontrolled rectifier has its input terminal connected to the low-voltage output terminal of a transformer and its output terminal connected to the input terminal of a DC / DC converter. It is used to rectify AC power into DC power. The DC / DC converter has its input terminal connected to the output terminal of an uncontrolled rectifier and its output terminal connected to an electrolytic cell to provide adjustable DC power to the electrolytic cell. The controller is connected to the inverter with droop control and the DC / DC converter respectively. It is used to collect the frequency information of the AC bus in real time, generate DC current command value according to the droop control method, and output PWM control signal to the DC / DC converter. Specifically, it also includes: frequency deviation value The current command generation module within the input controller; In the current command generation module, set the rated output current of the DC / DC converter to... Set the droop control coefficient to ; Based on frequency deviation value Rated output current With droop control coefficient Calculate the DC current command value : ； DC current command value The current control module output to the controller indicates the target output current of the DC / DC converter.

2. The new energy electrolysis hydrogen production rectifier with off-grid adaptability according to claim 1, characterized in that, The uncontrolled rectifier uses a diode rectifier, and the DC / DC converter uses a buck circuit to achieve the voltage reduction effect of the DC / DC converter.

3. A new energy electrolysis hydrogen production control method with off-grid adaptability, used to control the new energy electrolysis hydrogen production rectifier with off-grid adaptability as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. The AC power output from the transformer is rectified by an uncontrolled rectifier to obtain a DC voltage input to the DC / DC converter. S2. Collect the real-time frequency value of the AC bus on the output side of the inverter with droop control, and calculate the frequency deviation value; the inverter output terminal is connected to the AC bus. S3. Generate a DC current command value based on the frequency deviation value to indicate the target output current of the DC / DC converter; S4. Collect the current actual output current value of the DC / DC converter and input the actual output current value and DC current command value to the controller; S5. The controller calculates and generates a PWM control signal, which is then sent to the DC / DC converter to adjust the output current. S6. Based on the adjustment results of the DC / DC converter output current, the speed regulation of the output power of the uncontrolled rectifier is realized, and the real-time response and balance adjustment of the electrolytic hydrogen production load to the frequency change of the new energy AC bus is completed. S3 specifically includes: S31, frequency deviation value The current command generation module within the input controller; S32. Set the rated output current of the DC / DC converter in the current command generation module to... Set the droop control coefficient to ; S33, Based on the frequency deviation value Rated output current With droop control coefficient Calculate the DC current command value : ； S34, Set DC current command value The current control module output to the controller indicates the target output current of the DC / DC converter.

4. The new energy electrolysis hydrogen production control method with off-grid adaptability according to claim 3, characterized in that, S2 specifically includes: S21. Acquire AC bus signal from the output terminal of the inverter with droop control, and extract the real-time frequency value f of the AC bus through a phase-locked loop; S22. Input the real-time frequency value f into the controller's frequency processing module and compare it with the preset frequency reference value. Perform the difference calculation to obtain the frequency deviation value. .

5. The new energy electrolysis hydrogen production control method with off-grid adaptability according to claim 3, characterized in that, S4 specifically includes: S41. Acquire the current actual output current value of the DC / DC converter. Real-time measurement is performed via a controller connected to the current sampling circuit; S42, change the actual output current value With DC current command value The current control module is input together with the controller; S43. In the current control module of the controller, the actual output current value is... With DC current command value Perform the difference calculation to obtain the current error signal. ; S44, Transfer the current error signal The PI controller and PR controller, which are input to the PWM control signal generation module, drive the output process of the PWM control signal.

6. The new energy electrolysis hydrogen production control method with off-grid adaptability according to claim 3, characterized in that, S5 specifically includes: S51, In the PWM control signal generation module, based on the current error signal... Set PWM modulation parameters, including switching frequency. The adjustment range of the duty cycle D; S52, according to Using PWM modulation parameters, a PWM control signal sequence for driving the DC / DC converter is generated through modulation calculations. S53. Send the PWM control signal sequence to the power drive unit of the DC / DC converter, adjust the actual current value output by the converter, and apply the target current to the electrolytic cell.

7. The new energy electrolysis hydrogen production control method with off-grid adaptability according to claim 3, characterized in that, S6 specifically includes: S61. Acquire the output current value of the DC / DC converter after being driven by the PWM signal, and determine whether it has approached the current command value. ; S62, When the output current value matches the DC current command value The error between them is lower than the set threshold At this point, it is determined that the DC / DC converter has reached a stable output state; S63. The actual current value under stable output conditions is used as the basis for the current output power of the uncontrolled rectifier, and the current actual output power is calculated through the uncontrolled rectifier power feedback module. ; S64, Actual output power Feedback is sent to the inverter droop control logic to adjust the AC bus frequency in a coordinated manner, thereby forming a real-time adaptive droop balance between the uncontrolled rectifier load power and the renewable energy power supply frequency.

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