Cooperative control method and device for electrolytic hydrogen production hybrid rectification system

Abstract

The invention discloses a cooperative control method and device for an electrolytic hydrogen production hybrid rectification system, and the method comprises the steps: collecting the three-phase voltage and three-phase current of a power grid side, and the voltage of a DC bus, and extracting a harmonic current component and a reactive current component of the power grid side based on the three-phase voltage and the three-phase current; the total power needed by the electrolytic cell is decomposed into target fundamental wave power distributed to the main power unit and target compensation power distributed to the compensation unit; according to the target fundamental wave power and the voltage of the direct current bus, generating a duty ratio instruction to adjust the actual fundamental wave power output by the main power unit to the direct current bus, so that the actual fundamental wave power is matched with the target fundamental wave power; and according to the target compensation power, the harmonic current component and the reactive current component, generating a total current reference instruction to control the compensation unit to output compensation current to the DC bus. According to the invention, stable fundamental power supply, rapid power fluctuation compensation, power grid harmonic suppression and reactive compensation can be synchronously realized, and the efficiency and stability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a collaborative control method and apparatus for an electrolytic hydrogen production hybrid rectifier system. Background Technology

[0002] With the rapid development of renewable energy power generation, water electrolysis for hydrogen production has attracted widespread attention as an important technological route for green hydrogen production. High-power electrolysis hydrogen production hybrid rectifier systems place high demands on the power supply, requiring high power ratings, high power quality, high dynamic response, and high reliability.

[0003] Existing high-power electrolytic hydrogen production hybrid rectification systems use a combination of diodes and IGBTs (insulated gate bipolar transistors) for rectification, but they suffer from harmonic pollution, reactive power loss, inability to quickly compensate for power fluctuations, and insufficient DC bus stability, which leads to reduced electrolyzer operating efficiency and shortened lifespan.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This specification provides a collaborative control method and apparatus for an electrolytic hydrogen production hybrid rectification system to solve the problems of harmonic pollution, reactive power loss, inability to quickly compensate for power fluctuations, and insufficient DC bus stability in existing electrolytic hydrogen production hybrid rectification systems.

[0006] In a first aspect, embodiments of this specification provide a collaborative control method for an electrolytic hydrogen production hybrid rectification system. The electrolytic hydrogen production hybrid rectification system includes a main power unit and a compensation unit. The output terminals of both the main power unit and the compensation unit are connected to a DC bus supplying power to the electrolyzer. The method includes: Collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. Obtain the total power required by the electrolytic cell, and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit; Based on the target fundamental power and the voltage of the DC bus, a duty cycle command is generated to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. Based on the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation portion of the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

[0007] In some embodiments, the electrolytic hydrogen production hybrid rectification system further includes an integrated multi-winding transformer, which has an input winding and at least three low-voltage output windings. The input winding is connected to the grid side and is used to transform the AC power from the grid side and distribute it to each low-voltage output winding. The input terminal of the main power unit is connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. The input terminal of the compensation unit is connected to the third low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier. The duty cycle command is used to regulate the switching of the DC-DC converter to adjust the actual fundamental power output by the main power unit to the DC bus, and the total current reference command is used to control the rectifier to output compensation current to the DC bus.

[0008] In some embodiments, extracting the harmonic current component and reactive current component from the grid side based on the three-phase voltage and three-phase current includes: The three-phase voltage and three-phase current are transformed to the αβ stationary coordinate system to obtain the voltage component along the α axis, the voltage component along the β axis, the current component along the α axis, and the current component along the β axis. Calculate the instantaneous active power and instantaneous reactive power based on the voltage component of the α-axis, the voltage component of the β-axis, the current component of the α-axis, and the current component of the β-axis. The DC components of instantaneous active power and instantaneous reactive power are extracted by using a low-pass filter. Subtracting the DC component of the instantaneous active power from the instantaneous active power yields the AC component of the instantaneous active power; subtracting the DC component of the instantaneous reactive power from the instantaneous reactive power yields the AC component of the instantaneous reactive power. The harmonic current components are obtained by performing two inverse transformations on the AC components of instantaneous active power and instantaneous reactive power. Calculate the reactive current component based on the DC component of the instantaneous reactive power.

[0009] In some embodiments, the step of performing two inverse transformations on the AC components of instantaneous active power and instantaneous reactive power to obtain harmonic current components includes: The AC components of instantaneous active power and instantaneous reactive power are transformed by the first inverse transformation to obtain the harmonic current components of the α-axis and the β-axis in the αβ stationary coordinate system. The harmonic current components along the α-axis and β-axis are subjected to a second inverse transformation to obtain the three-phase harmonic current components. The instantaneous values ​​of the three-phase harmonic current components are taken as the harmonic current components. The calculation of the reactive current component based on the DC component of the instantaneous reactive power includes: The reactive current component is determined based on the ratio of the DC component of the instantaneous reactive power to the grid voltage amplitude, wherein the grid voltage amplitude is determined based on the three-phase voltage on the grid side. The first inverse transformation is a transformation from power quantity to current quantity in the αβ stationary coordinate system, and the second inverse transformation is a Clarke inverse transformation from the αβ stationary coordinate system to the abc three-phase coordinate system.

[0010] In some embodiments, decomposing the total power into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit includes: The total power is low-pass filtered, and the slow-changing DC component obtained after filtering is taken as the target fundamental power, which is the main power component for hydrogen production in the electrolyzer. The difference between the total power and the target fundamental power is taken as the power fluctuation component; Harmonic compensation components are generated based on the harmonic current components, and reactive compensation components are generated based on the reactive current components. The power fluctuation component, harmonic compensation component, and reactive power compensation component are combined to form the target compensation power, which is the auxiliary compensation power component for hydrogen production power supply in the electrolyzer.

[0011] In some embodiments, generating the duty cycle command based on the target fundamental power and the DC bus voltage includes: The target output current of the DC converter in the main power unit is determined based on the ratio of the target fundamental power to the voltage of the DC bus. Collect the actual output current of the DC-DC converter in the main power unit, and calculate the first current error between the target output current and the actual output current of the DC-DC converter. The duty cycle adjustment is calculated based on the first current error and the first proportional coefficient and first integral coefficient of the regulator. The first proportional coefficient and first integral coefficient are set according to the inductance value, switching frequency and desired current loop cutoff frequency of the DC converter. The feedforward duty cycle is determined based on the ratio of the voltage of the DC bus to the average voltage output of the two 6-pulse diode rectifier bridges in the main power unit. The duty cycle adjustment amount and the feedforward duty cycle are superimposed to obtain the initial duty cycle, and the initial duty cycle is limited to a preset range to generate a duty cycle command.

[0012] In some embodiments, calculating the duty cycle adjustment based on the first current error and a preset first proportional coefficient and a first integral coefficient includes: Calculate the duty cycle adjustment amount using the following formula:

[0013] in, This is the duty cycle adjustment amount; This is the first proportional system; e is the first integral coefficient; I This is the first current error.

[0014] In some embodiments, generating a total current reference command based on the target compensation power, harmonic current components, and reactive current components includes: Based on the power fluctuation component in the target compensation power, an active current command for the d-axis in the dq rotating coordinate system is generated. Take the opposite phase of the reactive current component to generate a reactive current command for the q-axis in the dq rotating coordinate system; Take the opposite phase of the harmonic current component to generate a three-phase harmonic current command in the abc three-phase coordinate system; The active current command and reactive current command are sequentially subjected to the third inverse transformation and the second inverse transformation, and then superimposed with the three-phase harmonic current command to synthesize the total current reference command in the abc three-phase coordinate system. The third inverse transformation is the Park inverse transformation from the dq rotating coordinate system to the αβ stationary coordinate system.

[0015] In some embodiments, generating an active current command along the d-axis in the dq rotating coordinate system based on the power fluctuation component in the target compensation power includes: The active current command along the d-axis in the dq rotating coordinate system is generated according to the following formula:

[0016] in, This is the active current command for the d-axis in the dq rotating coordinate system; Pwave For power fluctuation components; U d Let be the grid voltage along the d-axis in the dq rotating coordinate system, and its value is equal to the grid voltage amplitude. The process of sequentially performing a third inverse transformation and a second inverse transformation on the active current command and the reactive current command, and then superimposing them with the three-phase harmonic current command to synthesize a total current reference command in the abc three-phase coordinate system, includes: The active current command and reactive current command are transformed by the third inverse transformation to obtain the fundamental current command of the α axis and the fundamental current command of the β axis in the αβ stationary coordinate system. The fundamental current command of the α-axis and the fundamental current command of the β-axis are transformed by a second inverse transformation to obtain the three-phase fundamental current command in the abc three-phase coordinate system. The three-phase fundamental current command and the three-phase harmonic current command are superimposed to obtain the total current reference command in the abc three-phase coordinate system.

[0017] In some embodiments, controlling the compensation unit to output compensation current to the DC bus includes: Calculate the voltage feedforward term based on the three-phase voltage and three-phase current on the grid side and the AC side inductance of the rectifier in the compensation unit; The actual AC output current of the rectifier in the compensation unit is collected, and the second current error between the total reference current in the total current reference command and the actual AC output current of the rectifier is calculated. The current feedback correction is calculated based on the second current error and the second proportional coefficient and second integral coefficient of the regulator. The second proportional coefficient and second integral coefficient are set according to the inductance value of the rectifier, the switching frequency and the desired current loop cutoff frequency. The voltage feedforward term is added to the current feedback correction to obtain a pulse width modulation wave signal; Based on the pulse width modulation wave signal, the switching transistor of the rectifier in the compensation unit is controlled to turn on and off, so that the compensation unit outputs compensation current to the DC bus.

[0018] In some embodiments, the method further includes: A rate limit is applied to the target fundamental power so that the rate of change of the target fundamental power is less than a preset rate threshold, but no rate limit is applied to the target compensation power; When a sudden change in the total power is detected, the sudden change component is allocated to the target compensation power, so that the compensation unit generates a corresponding compensation current according to the sudden change component to make up for the power deficit. At the same time, the actual fundamental power of the main power unit approaches the target fundamental power at a limited rate until the total power stops changing.

[0019] In some embodiments, the method further includes: The system collects real-time operating data, including the inductor ripple current of the DC converter, the ripple current of the AC side inductor of the rectifier in the compensation unit, and the operating parameters of each power device. The system operating data includes the total output power, DC bus voltage, actual output power of the main power unit, and actual output power of the compensation unit. Based on the actual output power of the power unit and the DC bus voltage, the average on-state current of the 6-pulse diode rectifier bridge in the main power unit is calculated, and combined with the inductor ripple current of the DC converter, the first effective on-state current of the fully controlled switch in the DC converter is calculated. Based on the actual output power of the compensation unit and the DC bus voltage, the average output current of the compensation unit is calculated, and combined with the ripple current of the AC side inductor of the rectifier of the compensation unit, the second effective conduction current of the fully controlled switch in the rectifier is calculated. The collected operating parameters of each power device, as well as the average on-state current, the first effective on-state current, and the second effective on-state current, are input into a preset power device loss model, and the total system loss is output. The total system loss is the sum of the main power unit loss and the compensation unit loss. Based on the total system loss, total output power, and DC bus voltage, an optimal power allocation coefficient is determined. This optimal power allocation coefficient is used to dynamically adjust the allocation ratio between the target fundamental power and the target compensation power so that the total system loss is less than a preset loss threshold. The operating parameters of each power device include the forward voltage drop of the rectifier diode in the 6-pulse diode rectifier bridge; the first on-state voltage drop, first switching frequency, first single turn-on loss, and first single turn-off loss of the fully controlled switch in the DC converter; and the second on-state voltage drop, second switching frequency, second single turn-on loss, and second single turn-off loss of the fully controlled switch in the rectifier.

[0020] In some embodiments, the power device loss model includes a main power unit loss sub-model and a compensation unit loss sub-model. The main power unit loss sub-model includes a rectifier diode conduction loss model of a 6-pulse diode rectifier bridge, a first fully controlled switch conduction loss model and a first switching loss model of a DC-DC converter. The compensation unit loss sub-model includes a second fully controlled switch conduction loss model and a second switching loss model of a rectifier. The rectifier diode conduction loss model includes:

[0021] Among them, P D-cond V represents the total conduction loss of all 6-pulse diode rectifier bridges; n represents the total number of rectifier diodes in all 6-pulse diode rectifier bridges; VF I represents the forward voltage drop of the rectifier diodes in a 6-pulse diode rectifier bridge. D-avg This represents the average on-state current. The first fully controlled switch conduction loss model includes:

[0022] Among them, P S-cond V represents the total conduction loss of the DC-DC converter; m represents the total number of fully controlled switches in the DC-DC converter; V S-on I is the first on-state voltage drop of the fully controlled switch in the DC-DC converter; S-rms This is the first effective on-state current; The first switching loss model includes:

[0023] Among them, P S-sw The total switching loss of the DC-DC converter is given by E; k is the number of bridge arms of the DC-DC converter; E on1 For the first single activation loss; E off1 For the first single shutdown loss; f sw1 The first switching frequency; The main power unit loss is the sum of the total conduction loss of all 6-pulse diode rectifier bridges, the total conduction loss of the DC-DC converter, and the total switching loss of the DC-DC converter.

[0024] In some embodiments, the second fully controlled switch conduction loss model includes:

[0025] Among them, P IGBT-cond denoted as the total conduction loss of the rectifier; p represents the total number of fully controlled switching transistors in the rectifier. This is the second on-state voltage drop of the fully controlled switch in the rectifier; This is the second effective on-state current; The second switching loss model includes:

[0026] Among them, P S-sw q represents the total switching loss of the rectifier; q represents the number of bridge arms of the rectifier; E on2 For the second single activation loss; E off2 For the second single shutdown loss; f sw2 This is the second switching frequency; The loss of the compensation unit is the sum of the total conduction loss and the total switching loss of the rectifier.

[0027] In some embodiments, determining the optimal power allocation coefficient based on the total system loss and total output power includes: Set an initial power allocation coefficient, and based on the initial power allocation coefficient and the total output power, determine the target fundamental power allocation value and the target compensation power allocation value before the disturbance; Starting from the initial power allocation coefficient, a preset perturbation is applied to obtain the perturbed power allocation coefficient. Based on the perturbed power allocation coefficient and the total output power, the perturbed target fundamental power allocation value and target compensation power allocation value are determined. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device corresponding to the target fundamental power allocation value and the target compensation power allocation value before the disturbance are input into the preset power device loss model, and the total system loss before the disturbance is output. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device are input into the preset power device loss model after the perturbation of the target fundamental power allocation value and the target compensation power allocation value, and the total system loss after the perturbation is output. The difference between the total system loss after the disturbance and the total system loss before the disturbance is calculated to obtain the change in total system loss. If the change in the total system loss is less than zero, it means that the direction of the disturbance reduces the total loss, so the disturbance continues to be applied in the same direction; if the change in the total system loss is greater than zero, it means that the direction of the disturbance increases the total loss, so the disturbance is applied in the opposite direction. Repeat the above steps of applying the disturbance, calculating the total system loss before and after the disturbance, and determining the direction until the change in the total system loss converges to the preset change threshold. Then, take the power allocation coefficient obtained after the disturbance as the optimal power allocation coefficient.

[0028] Secondly, embodiments of this specification also provide a cooperative control system, including: An integrated multi-winding transformer has one input winding and at least three low-voltage output windings; The main power unit has its input terminal connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer. It is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. A compensation unit, the input terminal of which is connected to the third low-voltage output winding of the integrated multi-winding transformer, is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier; and... The cooperative controller is used to execute the cooperative control method described above.

[0029] Thirdly, embodiments of this specification also provide a collaborative control device for an electrolytic hydrogen production hybrid rectification system. The electrolytic hydrogen production hybrid rectification system includes a main power unit and a compensation unit. The output terminals of both the main power unit and the compensation unit are connected to a DC bus supplying power to the electrolyzer. The device includes: The extraction module is used to collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. The decomposition module is used to obtain the total power required by the electrolytic cell and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit. The main power unit adjustment module is used to generate a duty cycle command based on the target fundamental power and the voltage of the DC bus, so as to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. The compensation unit control module is used to generate a total current reference command based on the target compensation power, harmonic current component, and reactive current component, so as to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current component to achieve harmonic suppression, and to cancel the reactive current component to achieve reactive power compensation.

[0030] Fourthly, embodiments of this specification also provide an electronic device, including: a memory and a processor, wherein the processor and the memory are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to realize the steps of the above-described coordinated control method for an electrolytic hydrogen production hybrid rectification system.

[0031] Fifthly, embodiments of this specification also provide a computer-readable storage medium storing computer program instructions thereon, which, when executed by a processor, implement the steps of the above-described coordinated control method for an electrolytic hydrogen production hybrid rectification system.

[0032] Sixthly, embodiments of this specification also provide a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the above-described coordinated control method for an electrolytic hydrogen production hybrid rectification system.

[0033] This specification provides a method and apparatus for coordinated control of a hybrid rectification system for electrolytic hydrogen production. The system includes a main power unit and a compensation unit, both connected to a DC bus supplying power to the electrolyzer. The method includes: first, acquiring the three-phase voltage, three-phase current, and DC bus voltage from the power grid; and extracting harmonic current and reactive current components from the power grid based on the three-phase voltage and current. Then, acquiring the total power required by the electrolyzer and decomposing it into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit. Finally, generating a duty cycle command based on the target fundamental power and the DC bus voltage to adjust the actual fundamental power output from the main power unit to the DC bus, matching the target fundamental power. Based on the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. This compensation current responds to the power fluctuation portion of the target compensation power to achieve power fluctuation compensation, and is used to offset the harmonic current components to achieve harmonic suppression, and to offset the reactive current components to achieve reactive power compensation. In this embodiment, by real-time acquisition of the three-phase voltage and three-phase current on the grid side and extraction of harmonic current components and reactive current components, a precise compensation target can be provided for the subsequent compensation unit. By decomposing the total power into target fundamental power and target compensation power, and allocating them to power units with different characteristics, a division of labor and coordination can be achieved, with the main power unit handling steady-state power and the compensation unit handling fluctuating power, balancing system efficiency and dynamic response speed, while also enabling rapid smoothing of DC bus power fluctuations. By generating a duty cycle command based on the target fundamental power and the DC bus voltage, the output power can be precisely adjusted to provide stable fundamental power support for the DC bus. By generating a total current reference command based on the target compensation power, harmonic current components, and reactive current components, and controlling the compensation unit to output compensation current to the DC bus, power fluctuation compensation, harmonic suppression, and reactive power compensation can be achieved simultaneously, thereby comprehensively improving system efficiency and stability. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic flowchart of a collaborative control method for an electrolytic hydrogen production hybrid rectification system provided in the embodiments of this specification; Figure 2 This is a schematic diagram of the structural composition of a collaborative control system provided in the embodiments of this specification; Figure 3 This is a schematic diagram of the structural composition of a collaborative control device for an electrolytic hydrogen production hybrid rectification system provided in the embodiments of this specification; Figure 4 This is a schematic diagram of the structural composition of the electronic device provided in the embodiments of this specification.

[0035] Explanation of reference numerals in the attached figures: 1. Power grid; 2. Integrated multi-winding transformer; 21. Input winding; 22. First low-voltage output winding; 23. Second low-voltage output winding; 24. Third low-voltage output winding; 3. Main power unit; 31. First 6-pulse diode rectifier bridge; 32. Second 6-pulse diode rectifier bridge; 33. DC converter; 4. Compensation unit; 41. Rectifier; 42. H-bridge; 5. DC bus; 6. Electrolytic cell; 7. Filter. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0037] As mentioned earlier, with the rapid development of renewable energy power generation, water electrolysis hydrogen production technology is developing towards large-scale, high-efficiency, and low-cost directions. High-power water electrolysis hydrogen production power supplies need to meet the following requirements: high power level (such as a single system reaching MW level or even 10MW or more), high power quality (such as low DC output ripple to avoid aging of electrolyzer electrodes), high dynamic response (such as adapting to the volatility of new energy sources such as wind power and photovoltaics), and high reliability (such as ensuring continuous hydrogen production to avoid downtime losses).

[0038] Existing high-power electrolytic hydrogen production hybrid rectification systems use a combination of diodes and IGBTs (insulated gate bipolar transistors) for rectification, but they suffer from core problems such as harmonic pollution, reactive power loss, inability to quickly compensate for power fluctuations, and insufficient DC bus stability.

[0039] The above problems arise because: the diode rectifier unit generates a large number of low-order characteristic harmonics (5th, 7th, 11th, 13th, etc.), while the IGBT unit generates high-frequency switching harmonics. The two types of harmonics interfere with each other, resulting in high harmonic content on the grid side, low power factor, and increased output voltage ripple, which threatens the life of the electrolytic cell; the diode rectifier unit is uncontrollable and cannot respond quickly to power fluctuations, while the IGBT unit has limited capacity and cannot independently undertake the task of compensating for high power fluctuations; the two rectifier units are controlled independently, lacking a system-level power distribution and dynamic coordination mechanism, which makes it impossible to quickly smooth out power fluctuations and results in poor DC bus voltage stability.

[0040] To address the aforementioned issues, this specification provides a collaborative control method and apparatus for a hybrid rectifier system for hydrogen electrolysis. Through power decoupling and collaborative control, the compensation unit can simultaneously achieve power fluctuation compensation, harmonic suppression, and reactive power compensation. This solves the problems of harmonic pollution, reactive power loss, inability to quickly compensate for power fluctuations, and insufficient DC bus stability in existing hybrid rectifier systems, achieving the technical effects of high overall system efficiency, good power quality, fast dynamic response, and long electrolyzer life.

[0041] It should be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, it does not mean that this application has used or necessarily used such a solution.

[0042] See Figure 1 As shown in the embodiments of this specification, a collaborative control method for an electrolytic hydrogen production hybrid rectification system is provided. The electrolytic hydrogen production hybrid rectification system includes a main power unit and a compensation unit. The output terminals of the main power unit and the compensation unit are both connected to the DC bus that supplies power to the electrolyzer. In specific implementation, the method may include the following: S101: Collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. S102: Obtain the total power required by the electrolytic cell, and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit; S103: Generate a duty cycle command based on the target fundamental power and the voltage of the DC bus to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power; S104: Based on the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

[0043] Based on the above embodiments, by real-time acquisition of three-phase voltage and three-phase current on the grid side and extraction of harmonic current components and reactive current components, accurate compensation targets can be provided for subsequent compensation units, laying the foundation for grid harmonic suppression and reactive power compensation. This effectively solves the problems of high grid harmonic pollution and high reactive power loss in existing hybrid rectification schemes. By decomposing the total power into target fundamental power and target compensation power, the high-efficiency but slow-response main power unit can handle steady-state fundamental power, while the high-dynamic-response but small-capacity compensation unit can handle fluctuation and compensation power. This achieves a reasonable division of labor and coordinated operation between the master and slave power units, effectively solving the technical problems of existing hybrid rectification schemes that are difficult to balance system efficiency and dynamic response speed, and that DC bus power fluctuations cannot be quickly smoothed out. By generating duty cycle commands based on the target fundamental power and DC bus voltage, the output power of the main power unit can be precisely adjusted, providing stable and reliable fundamental power support for the DC bus. This effectively solves the technical problems of insufficient DC bus power supply stability and low power regulation accuracy in existing hybrid rectification schemes. By generating a total current reference command based on the target compensation power, harmonic current components, and reactive current components, and controlling the compensation unit to output compensation current to the DC bus, it is possible to simultaneously achieve rapid power fluctuation suppression, grid harmonic suppression, and reactive power compensation. This effectively solves the technical problem that existing hybrid rectification schemes cannot simultaneously achieve dynamic compensation, harmonic control, and reactive power regulation.

[0044] In some embodiments, the above-mentioned electrolytic hydrogen production hybrid rectification system may further include an integrated multi-winding transformer, which has an input winding and at least three low-voltage output windings. The input winding is connected to the grid side and is used to transform the AC power from the grid side and distribute it to each low-voltage output winding. The input terminal of the main power unit is connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. The input terminal of the compensation unit is connected to the third low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier. The duty cycle command is used to regulate the switching of the DC-DC converter to adjust the actual fundamental power output by the main power unit to the DC bus, and the total current reference command is used to control the rectifier to output compensation current to the DC bus.

[0045] For details, please refer to Figure 2 As shown, the electrolytic hydrogen production hybrid rectification system can include at least an integrated multi-winding transformer 2, a main power unit 3, a compensation unit 4, a DC bus 5, and an electrolytic cell 6.

[0046] The integrated multi-winding transformer 2 can have one input winding 21 and at least three low-voltage output windings (such as a first low-voltage output winding 22, a second low-voltage output winding 23, and a third low-voltage output winding 24). The input winding 21 (or high-voltage winding) can be used to connect to the power grid 1 or a new energy AC bus (such as 10kV / 35kV), and can transform and distribute the AC power from the power grid 1 side to each low-voltage output winding. Among the three low-voltage output windings, the first low-voltage output winding 22 can be connected in a star (Y) configuration and can be used to power the first 6-pulse diode rectifier bridge 31. The second low-voltage output winding 23 can be connected in a delta (Δ) configuration and can be used to power the second 6-pulse diode rectifier bridge 32. The first low-voltage output winding 22 and the second low-voltage output winding 23 are 30° out of phase, together forming an equivalent 12-pulse rectification, which can significantly suppress the 5th and 7th characteristic harmonics on the grid side. The third low-voltage output winding 24 can be star-connected (Y) with a neutral point grounded, and can be used to power the compensation unit 4. The neutral point grounding structure can effectively suppress high-frequency common-mode interference. The winding parameters can be designed as follows: The short-circuit impedance of the first and second low-voltage output windings can be designed to be 5%~8% (typically 6%), which can be used to limit fault current and ensure current sharing. The short-circuit impedance of the third low-voltage output winding can be designed to be 3%~5% (typically 4%) to improve the dynamic response speed of the compensation unit. A double-layer electromagnetic shielding structure can be set between the input winding and the low-voltage output winding, as well as between each low-voltage output winding. The double-layer electromagnetic shielding structure can include an inner copper foil shielding layer and an outer silicon steel sheet shielding layer. This structure can effectively block the coupling of high and low frequency harmonic magnetic fields between windings and prevent electromagnetic interference.

[0047] The input terminal of the main power unit 3 is connected to the first low-voltage output winding 22 and the second low-voltage output winding 23. The main power unit 3 may include two 6-pulse diode rectifier bridges (i.e., a first 6-pulse diode rectifier bridge 31 and a second 6-pulse diode rectifier bridge 32) and a DC-DC converter 33 connected in series with the output terminals of the two 6-pulse diode rectifier bridges. The first 6-pulse diode rectifier bridge 31 is connected to the first low-voltage output winding 22, and the second 6-pulse diode rectifier bridge 32 is connected to the second low-voltage output winding 23, which can be used to rectify AC power into DC power. The DC-DC converter 33 may be a three-phase interleaved Buck converter, with its input terminal connected in parallel with the output terminals of the two 6-pulse diode rectifier bridges, and its output terminal connected to the DC bus 5 via a smoothing reactor, which can be used to convert higher DC voltage to lower DC voltage. By controlling the duty cycle of the switching transistors of the three-phase interleaved Buck converter, precise and continuous adjustment of the fundamental power output of the main power unit can be achieved. Three-phase interleaved Buck converters can be driven by PWM (pulse width modulation) waveforms with a 120° phase shift, which can effectively reduce output current ripple and reduce filter size.

[0048] The input terminal of compensation unit 4 (or IGBT rectifier compensation unit) is connected to the third low-voltage output winding 24. Compensation unit 4 may include a PWM rectifier 41 and an H-bridge 42. The PWM rectifier 41 may adopt a three-phase full-bridge structure and can be used to draw power from the third low-voltage output winding 24, converting AC to adjustable DC, which is then connected to the DC bus 5 after passing through the H-bridge 42. The input terminal of the H-bridge 42 is connected to the output terminal of the PWM rectifier 41, and the output terminal is connected to the DC bus 5. The H-bridge 42 can be used to realize DC voltage buck-boost regulation and fast power response, injecting or absorbing compensation current into the DC bus 5, and quickly smoothing the power fluctuation of the DC bus 5. This compensation unit 4 can undertake: power fluctuation component compensation, dynamic compensation of harmonics and reactive current, and rapid regulation of DC bus voltage. The H-bridge can also be called an IGBT (Insulated Gate Bipolar Transistor) full-bridge.

[0049] The DC bus 5 may include a positive bus and a negative bus, which can be used to collect the DC power output from the main power unit 3 and the compensation unit 4. The positive terminal of the DC bus 5 is connected to the positive input terminal of the electrolytic cell 6, and the negative terminal of the DC bus 5 is connected to the negative input terminal of the electrolytic cell 6. The electrolytic cell 6, as the final load, can use DC power to perform water electrolysis, decomposing water into hydrogen and oxygen.

[0050] In some embodiments, the input winding 21 can be connected to the power grid 1 via a filter 7. The filter 7 can be used to filter high-frequency harmonic components and suppress harmonic interference to the input winding 21.

[0051] In some embodiments, the PWM rectifier 41 described above may be replaced with a third 6-pulse diode rectifier bridge, and the H-bridge 42 described above may be replaced with a subsequent phase-shifted full-bridge DC / DC isolated converter (PSFB), depending on actual needs. This specification does not make specific limitations in this regard.

[0052] Based on the above embodiments, the AC power from the power grid is stepped down by an integrated multi-winding transformer and then split into two paths. The first path is rectified into DC power by two 6-pulse diode rectifier bridges, and then regulated by a three-phase interleaved Buck converter before being output to the DC bus, undertaking the main power transmission. The second path is rectified into DC power by a PWM rectifier and output to the DC bus, undertaking dynamic compensation and power quality management. The power from both paths is superimposed on the DC bus to power the electrolytic cell.

[0053] By adopting an integrated multi-winding transformer architecture, a high degree of integration of the transformer, main power unit, and compensation unit is achieved, significantly reducing equipment footprint and construction costs, and substantially improving system integration, modular expansion, and intelligent operation and maintenance capabilities. Through the rational division of labor and collaborative control between the master and slave power units, the high efficiency of the main power unit and the dynamic compensation advantage of the compensation unit are fully utilized, improving the overall system operating efficiency. Simultaneously, relying on the integrated topology and collaborative control mechanism, fault isolation can be achieved, preventing system downtime caused by a single component failure, effectively improving system reliability and mean time between failures (MTBF).

[0054] In some embodiments, the extraction of harmonic current components and reactive current components from the grid side based on the three-phase voltage and three-phase current in S101 above may, in specific implementation, include: The three-phase voltage and three-phase current are transformed to the αβ stationary coordinate system to obtain the voltage component along the α axis, the voltage component along the β axis, the current component along the α axis, and the current component along the β axis. Calculate the instantaneous active power and instantaneous reactive power based on the voltage component of the α-axis, the voltage component of the β-axis, the current component of the α-axis, and the current component of the β-axis. The DC components of instantaneous active power and instantaneous reactive power are extracted by using a low-pass filter. Subtracting the DC component of the instantaneous active power from the instantaneous active power yields the AC component of the instantaneous active power; subtracting the DC component of the instantaneous reactive power from the instantaneous reactive power yields the AC component of the instantaneous reactive power. The harmonic current components are obtained by performing two inverse transformations on the AC components of instantaneous active power and instantaneous reactive power. Calculate the reactive current component based on the DC component of the instantaneous reactive power.

[0055] In some embodiments, the above-mentioned inverse transformation of the AC component of instantaneous active power and the AC component of instantaneous reactive power to obtain the harmonic current component includes: The AC components of instantaneous active power and instantaneous reactive power are transformed by the first inverse transformation to obtain the harmonic current components of the α-axis and the β-axis in the αβ stationary coordinate system. The harmonic current components along the α-axis and β-axis are subjected to a second inverse transformation to obtain the three-phase harmonic current components. The instantaneous values ​​of the three-phase harmonic current components are taken as the harmonic current components. The reactive current component is determined based on the ratio of the fundamental reactive power to the grid voltage amplitude, wherein the grid voltage amplitude is determined based on the three-phase voltage on the grid side. The first inverse transformation is a transformation from power quantity to current quantity in the αβ stationary coordinate system, and the second inverse transformation is a Clarke inverse transformation from the αβ stationary coordinate system to the abc three-phase coordinate system.

[0056] Specifically, in this embodiment, the harmonic current component i is extracted. h and reactive current component i q The specific implementation method can be as follows: First, the three-phase voltage u on the grid side is acquired using a voltage sensor. a u b u c The three-phase current i on the grid side is collected by a current sensor. a i b i c .

[0057] Then, the Clarke transformation is used to transform the three-phase voltage and three-phase current to the αβ stationary coordinate system (the Clarke transformation transforms the abc three-phase coordinate system to the αβ stationary coordinate system). The transformation formula is as follows: .

[0058] Wherein, the transformation matrix C of the Clarke transform 32 It can be as follows: .

[0059] After transformation, the voltage component u along the α axis is obtained. α Voltage component u along the β axis β Current component i along the α axis α and the current component i along the β axis β .

[0060] Next, based on the voltage component u along the α axis α Voltage component u along the β axis β Current component i along the α axisα and the current component i along the β axis β Calculate the instantaneous active power p and instantaneous reactive power q according to the following formulas: .

[0061] Next, the DC component p of the instantaneous active power is extracted or separated by a low-pass filter (the cutoff frequency is usually set to 50 Hz). - and the DC component of instantaneous reactive power q - This corresponds to the fundamental active power and the fundamental reactive power.

[0062] Next, subtract the DC component of the instantaneous active power p from the instantaneous active power p. - The AC component of instantaneous active power is obtained. Subtract the DC component q of the instantaneous reactive power from the instantaneous reactive power q. - The AC component of instantaneous reactive power is obtained. These alternating current components correspond to harmonic power.

[0063] Next, the AC component of the instantaneous active power... AC component of instantaneous reactive power After the first inverse transformation, the harmonic current component i along the α-axis in the αβ stationary coordinate system is obtained. hα and the harmonic current component i along the β axis hβ (The first inverse transformation is from power quantity to current quantity in the αβ stationary coordinate system. When performing the inverse transformation on the AC component, it is necessary to combine the voltage component u on the α axis.) α Voltage component u along the β axis β The specific formula is as follows: .

[0064] Then the harmonic current component i along the α axis hα and the harmonic current component i along the β axis hβ After the second inverse transformation, the three-phase harmonic current components i are obtained. ha i hb i hc (The Clarke inverse transformation transforms the αβ stationary coordinate system to the abc three-phase coordinate system), taking the three-phase harmonic current component i ha i hb i hc The instantaneous value is taken as the harmonic current component i h The specific formula is as follows: .

[0065] Wherein, the inverse transformation matrix C of the inverse Clarke transform 23 It can be as follows: .

[0066] Harmonic current components i are extracted using the above steps. h Reactive current component i q Based on the fundamental reactive power q - and grid voltage amplitude U m The ratio is determined. Among them, the grid voltage amplitude U m It can be obtained by peak detection of the collected three-phase voltage on the grid side, or by calculation based on the effective value of the three-phase voltage.

[0067] In addition to the methods described above, in some embodiments, Fast Fourier Transform (FFT) can also be used to extract the harmonic current components i. h and reactive current component i q For example, performing FFT analysis on three-phase currents yields the amplitude and phase of each harmonic, and reconstructs the instantaneous values ​​of specific harmonics requiring compensation (such as the 5th, 7th, 11th, and 13th harmonics) into harmonic current components i. h Simultaneously, a component with a 90° phase difference from the voltage is separated from the fundamental current as the reactive current component i. q .

[0068] In some embodiments, the process of decomposing the total power into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit in S102 above may, in specific implementation, include: The total power is low-pass filtered, and the slow-changing DC component obtained after filtering is taken as the target fundamental power, which is the main power component for hydrogen production in the electrolyzer. The difference between the total power and the fundamental power is taken as the power fluctuation component; The harmonic compensation component is generated based on the harmonic current component, and the reactive power compensation component is generated based on the reactive current component. The power fluctuation component, harmonic compensation component, and reactive power compensation component are combined to form the target compensation power, which is the auxiliary compensation power component for hydrogen production power supply in the electrolyzer.

[0069] Specifically, in this embodiment, the total power P is... ref Decomposed into target fundamental power P diode and target compensation power P igbt The specific implementation method can be as follows: For the total power P ref Perform low-pass filtering (cutoff frequency is usually set to 0.5Hz~1Hz), and use the slow-varying DC component obtained after filtering as the target fundamental power P. diode Target fundamental power P diodeThe main power component that supplies power to the hydrogen production in the electrolyzer accounts for the vast majority of the total power and is undertaken by the main power unit, which can be allocated to the main power unit.

[0070] The total power P can be ref With fundamental power P diode The difference is taken as the power fluctuation component P. wave According to the harmonic current component i h Generate the harmonic compensation component P harm According to the reactive current component i q Generate the reactive power compensation component P reac The power fluctuation component P wave Harmonic compensation component P harm and reactive power compensation component P reac Combined into target compensation power P igbt Target compensation power P igbt The auxiliary compensation power component supplying power to the hydrogen production in the electrolyzer is borne by the compensation unit, and it can be allocated to the compensation unit. The synthesis formula is as follows: .

[0071] Among them, the harmonic compensation component P harm Specifically, it can be based on the harmonic current component i h With grid voltage amplitude U m The product is determined, and the reactive power compensation component P is determined. reac Specifically, it can be based on the reactive current component i q With grid voltage amplitude U m The product is determined according to the following formula: (Note the convention for reactive power symbols).

[0072] In some embodiments, the step of generating the duty cycle command based on the target fundamental power and the DC bus voltage in S103 above may, in specific implementation, include: The target output current of the converter in the main power unit is determined based on the ratio of the target fundamental power to the voltage of the DC bus. Collect the actual output current of the converter in the main power unit, and calculate the first current error between the target output current and the actual output current of the converter; The duty cycle adjustment is calculated based on the first current error and the first proportional coefficient and first integral coefficient of the regulator. The first proportional coefficient and first integral coefficient are set according to the inductance value, switching frequency and desired current loop cutoff frequency of the DC converter. The feedforward duty cycle is determined based on the ratio of the voltage of the DC bus to the average voltage output of the two 6-pulse diode rectifier bridges in the main power unit. The duty cycle adjustment amount and the feedforward duty cycle are superimposed to obtain the initial duty cycle, and the initial duty cycle is limited to a preset range to generate a duty cycle command.

[0073] In some embodiments, the calculation of the duty cycle adjustment based on the first current error and preset first proportional coefficient and first integral coefficient may, in specific implementation, include: Calculate the duty cycle adjustment amount using the following formula:

[0074] in, This is the duty cycle adjustment amount; This is the first proportional system; e is the first integral coefficient; I dt is the first current error; dt is the differential of the independent variable t, which is an infinitesimal change.

[0075] Specifically, the output power of the converter (three-phase interleaved Buck converter) can be precisely controlled by adjusting its duty cycle. In this embodiment, the specific implementation of generating the duty cycle command can be as follows: First, based on the target fundamental power P diode and the voltage U of the DC bus dc The ratio is used to determine the target output current of the converter in the main power unit according to the following formula. : .

[0076] Considering that the converter output is connected to the DC bus, its output current is the current injected into the bus.

[0077] Next, the actual output current I of the converter in the main power unit is collected. buck Calculate the target output current using the following formula. With the actual output current I of the converter buck The first current error e I : .

[0078] Next, a PI controller can be used, based on the first current error e. I and the first proportional coefficient of the regulator First integral coefficient Calculate the duty cycle adjustment amount according to the following formula. :

[0079] Among them, the first proportional coefficient First integral coefficient The frequency can be adjusted based on the inductance value of the DC-DC converter, the switching frequency, and the desired current loop cutoff frequency. For example: ,

[0080] Among them, L buck The inductor of the three-phase interleaved Buck converter; w c K represents the desired cutoff frequency. PWM This is the gain coefficient for PWM (Pulse Width Modulation), representing the proportional relationship between the modulated wave and the output voltage.

[0081] Next, considering that the output voltage of the diode rectifier bridge fluctuates with the mains voltage, a feedforward duty cycle D is introduced. ff It is based on the DC bus voltage U dc The average voltage U output from the two 6-pulse diode rectifier bridges in the main power unit diode The ratio is determined by the following formula:

[0082] Among them, U diode It can be obtained through detection or estimation.

[0083] Finally, adjust the duty cycle. and feedforward duty cycle D ff By superimposing these values, the initial duty cycle is obtained, as shown in the following formula: .

[0084] The initial duty cycle is limited to a preset range [0,1] to generate a duty cycle command. The duty cycle command can be used to control the on / off state of the DC-DC converter's switching transistors, thereby adjusting the actual fundamental power output from the main power unit to the DC bus. Specifically, the duty cycle command D can be assigned to the switching transistors of a three-phase interleaved Buck converter, driven by a 120° phase-shifted PWM waveform, to achieve interleaved parallel operation and reduce output ripple.

[0085] In some embodiments, generating a total current reference command based on the target compensation power, harmonic current components, and reactive current components in S104 above includes: Based on the power fluctuation component in the target compensation power, an active current command for the d-axis in the dq rotating coordinate system is generated. Take the opposite phase of the reactive current component to generate a reactive current command for the q-axis in the dq rotating coordinate system; Take the opposite phase of the harmonic current component to generate a three-phase harmonic current command in the abc three-phase coordinate system; The active current command and reactive current command are sequentially subjected to the third inverse transformation and the second inverse transformation, and then superimposed with the three-phase harmonic current command to synthesize the total current reference command in the abc three-phase coordinate system. The third inverse transformation is the Park inverse transformation from the dq rotating coordinate system to the αβ stationary coordinate system.

[0086] In some embodiments, generating the active current command along the d-axis in the dq rotating coordinate system based on the power fluctuation component in the target compensation power includes: The active current command along the d-axis in the dq rotating coordinate system is generated according to the following formula:

[0087] in, This is the active current command for the d-axis in the dq rotating coordinate system; P wave For power fluctuation components; U d Let be the grid voltage along the d-axis in the dq rotating coordinate system, and its value is equal to the grid voltage amplitude. The process of sequentially performing a third inverse transformation and a second inverse transformation on the active current command and the reactive current command, and then superimposing them with the three-phase harmonic current command to synthesize a total current reference command in the abc three-phase coordinate system, includes: The active current command and reactive current command are transformed by the third inverse transformation to obtain the fundamental current command of the α axis and the fundamental current command of the β axis in the αβ stationary coordinate system. The fundamental current command of the α-axis and the fundamental current command of the β-axis are transformed by a second inverse transformation to obtain the three-phase fundamental current command in the abc three-phase coordinate system. The three-phase fundamental current command and the three-phase harmonic current command are superimposed to obtain the total current reference command in the abc three-phase coordinate system.

[0088] Specifically, in this embodiment, the specific implementation of generating the total current reference command can be as follows: First, based on the target compensation power P igbt The power fluctuation component P in wave Generate active current command for the d-axis in the dq rotating coordinate system. The specific formula is as follows:

[0089] Among them, U d The grid voltage along the d-axis in the dq rotating coordinate system is obtained through a phase-locked loop, and its value is equal to the grid voltage amplitude Um.

[0090] Next, take the reactive current component i q The opposite phase generates the reactive current command along the q-axis in the dq rotating coordinate system. : Or based on the reactive power compensation requirement Q ref calculate, .

[0091] Take the harmonic current component i h The opposite phase generates three-phase harmonic current in the abc three-phase coordinate system. : .

[0092] Next, the active current command will be issued. Reactive current command The fundamental current command i along the α-axis in the αβ stationary coordinate system is obtained through the third inverse transformation. α and the fundamental current command i along the β axis β (The inverse Park transformation transforms the dq rotating coordinate system to the αβ stationary coordinate system), the specific formula is as follows:

[0093] in, The phase of the grid voltage obtained through the phase-locked loop; sin is the sine function; cos is the cosine function.

[0094] The fundamental current command i along the α axis α and the fundamental current command i along the β axis β After the second inverse transformation, the three-phase fundamental current command i in the abc three-phase coordinate system is obtained. base,a i base,b i base,c That is, the fundamental current command i along the a-axis base,a The fundamental current command i on the b-axis base,b The fundamental current command i on the c-axis base,c The specific formula is as follows: .

[0095] Finally, the three-phase fundamental current command i base,a i base,b i base,c With the three-phase harmonic current command By superimposing these values, the total current reference command i in the abc three-phase coordinate system is obtained. ref,abc That is, the total current reference command i for the a-axis. ref,a b-axis total current reference command i ref,b Total current reference command for the c-axis i ref,c The specific formula is as follows: .

[0096] In some embodiments, controlling the compensation unit to output compensation current to the DC bus in S104 above may include, in specific implementation, the following: Calculate the voltage feedforward term based on the three-phase voltage and three-phase current on the grid side and the AC side inductance of the rectifier in the compensation unit; The actual AC output current of the rectifier in the compensation unit is collected, and the second current error between the total reference current in the total current reference command and the actual AC output current of the rectifier is calculated. The current feedback correction is calculated based on the second current error and the second proportional coefficient and second integral coefficient of the regulator. The second proportional coefficient and second integral coefficient are set according to the inductance value of the rectifier, the switching frequency and the desired current loop cutoff frequency. The voltage feedforward term is added to the current feedback correction to obtain a pulse width modulation wave signal; Based on the pulse width modulation wave signal, the switching transistor of the rectifier in the compensation unit is controlled to turn on and off, so that the compensation unit outputs compensation current to the DC bus.

[0097] Specifically, in this embodiment, after generating the total current reference command, the specific implementation method for controlling the compensation unit to output the compensation current can be as follows: Based on the three-phase voltage u on the grid side a ,u b ,u c Three-phase current i a i b i c And the AC side inductance L of the rectifier in the compensation unit, the voltage feedforward term u is calculated according to the following formula. ff,abc That is, the voltage feedforward term u along the a-axis ff,a voltage feedforward term u on the b-axis ff,b voltage feedforward term u along the c-axis ff,c :

[0098] Where w is the grid angular frequency obtained through a phase-locked loop.

[0099] Next, calculate the total current reference command i. ref,abc The three-phase current i on the grid side abc The second current error e between (i.e., equal to the actual output current on the AC side of the rectifier) ​​and (i.e., the current error between) i,abc That is, the second current error e along the a-axis i,a The second current error e on the b-axis i,b The second current error e along the c-axis i,c : .

[0100] Next, a PI controller can be used, based on the second current error e. i,abc and the second proportional coefficient of the regulator Second integral coefficient Calculate the current feedback correction amount u according to the following formula. fb,abc That is, the current feedback correction amount u along the a-axis. fb,a b-axis current feedback correction amount u fb,b c-axis current feedback correction amount u fb,c :

[0101] Among them, the second proportionality coefficient Second integral coefficient The rectifier can be tuned based on its inductance, switching frequency, and desired current loop cutoff frequency. For example: ,

[0102] Where L is the AC side inductance of the rectifier.

[0103] Next, the voltage feedforward term u ff,abc With current feedback correction amount u fb,abc Adding them together yields the pulse width modulated wave signal u. PWM,abc That is, the pulse width modulated wave signal u along the a-axis PWM,a The pulse width modulated wave signal u along the b-axis PWM,b The pulse width modulation wave signal u along the c-axis PWM,c The specific formula is as follows: , , .

[0104] Finally, based on the pulse width modulated wave signal u PWM,abc A PWM (Pulse Width Modulation) drive signal is generated to control the switching of the switching transistors in the PWM rectifier, so that the compensation unit outputs compensation current to the DC bus.

[0105] In some embodiments, the above-described S102 process of decomposing the total power may further include, in specific implementations: A rate limit is applied to the target fundamental power so that the rate of change of the target fundamental power is less than a preset rate threshold, but no rate limit is applied to the target compensation power; When a sudden change in the total power is detected, the sudden change component is allocated to the target compensation power, so that the compensation unit generates a corresponding compensation current according to the sudden change component to make up for the power deficit. At the same time, the actual fundamental power of the main power unit approaches the target fundamental power at a limited rate until the total power stops changing.

[0106] Specifically, in this embodiment, a dynamic coordination step can be introduced to achieve a smooth power transition, and its specific implementation method is as follows: Power P ref Through two filters with different bandwidths: The low-pass filter (LPF, cutoff frequency 0.5 Hz) outputs P. diode It is allocated to the main power unit; The high-pass filter (HPF, cutoff frequency 0.5 Hz) outputs P. wave This information is allocated to the compensation unit as an active power fluctuation command on the IGBT side. In this way, the slow-changing DC component is handled by the main power unit (such as the diode side), while the fast-changing component is handled by the compensation unit (such as the IGBT side), naturally achieving priority adjustment of the IGBT.

[0107] Rate limiting: for target fundamental power P diode Apply rate limiting to reduce the target fundamental power P diode The rate of change is less than a preset rate threshold (e.g., 5% rated power / second), causing it to change slowly (reaching a new steady state in >200ms) to prevent DC-DC converter overshoot. The target compensation power P is not adjusted. igbt Apply a rate limit to enable the compensation unit to respond quickly (<5ms).

[0108] Transient coordination: upon detection of the total power P ref When a mutation occurs, the mutation component is allocated to the compensation unit, increasing the target compensation power P. igb This allows the compensation unit to generate a corresponding compensation current based on the abrupt change in power to make up for the power deficit, while simultaneously causing the actual fundamental power of the main power unit to approach the target fundamental power P at a constrained rate. diode until the total power P ref The abrupt change ceases. As time progresses, the output of the low-pass filter gradually tracks the new steady state, the power on the diode side slowly increases / decreases, and the power on the IGBT side correspondingly decreases, eventually reaching a new equilibrium.

[0109] This process is achieved naturally through the filter, without the need for a complex state machine, and ensures minimal fluctuations in the DC bus voltage. Through the aforementioned dynamic coordination steps, coordinated control is achieved, with the compensation unit prioritizing response and the main power unit providing smooth adjustment, thus ensuring the stability of the DC bus voltage.

[0110] In some embodiments, after S104 above, in specific implementation, it may further include: The system collects real-time operating data, including the inductor ripple current of the DC converter, the ripple current of the AC side inductor of the rectifier in the compensation unit, and the operating parameters of each power device. The system operating data includes the total output power, DC bus voltage, actual output power of the main power unit, and actual output power of the compensation unit. Based on the actual output power of the power unit and the DC bus voltage, the average on-state current of the 6-pulse diode rectifier bridge in the main power unit is calculated, and combined with the inductor ripple current of the DC converter, the first effective on-state current of the fully controlled switch in the DC converter is calculated. Based on the actual output power of the compensation unit and the DC bus voltage, the average output current of the compensation unit is calculated, and combined with the ripple current of the AC side inductor of the rectifier of the compensation unit, the second effective conduction current of the fully controlled switch in the rectifier is calculated. The collected operating parameters of each power device, as well as the average on-state current, the first effective on-state current, and the second effective on-state current, are input into a preset power device loss model, and the total system loss is output. The total system loss is the sum of the main power unit loss and the compensation unit loss. Based on the total system loss, total output power, and DC bus voltage, an optimal power allocation coefficient is determined. This optimal power allocation coefficient is used to dynamically adjust the allocation ratio between the target fundamental power and the target compensation power so that the total system loss is less than a preset loss threshold. The operating parameters of each power device include the forward voltage drop of the rectifier diode in the 6-pulse diode rectifier bridge; the first on-state voltage drop, first switching frequency, first single turn-on loss, and first single turn-off loss of the fully controlled switch in the DC converter; and the second on-state voltage drop, second switching frequency, second single turn-on loss, and second single turn-off loss of the fully controlled switch in the rectifier.

[0111] In some embodiments, the power device loss model includes a main power unit loss sub-model and a compensation unit loss sub-model. The main power unit loss sub-model includes a rectifier diode conduction loss model of a 6-pulse diode rectifier bridge, a first fully controlled switch conduction loss model and a first switching loss model of a DC-DC converter. The compensation unit loss sub-model includes a second fully controlled switch conduction loss model and a second switching loss model of a rectifier. The rectifier diode conduction loss model includes:

[0112] Among them, P D-condV represents the total conduction loss of all 6-pulse diode rectifier bridges; n represents the total number of rectifier diodes in all 6-pulse diode rectifier bridges; V F I represents the forward voltage drop of the rectifier diodes in a 6-pulse diode rectifier bridge. D-avg This represents the average on-state current. The first fully controlled switch conduction loss model includes:

[0113] Among them, P S-cond V represents the total conduction loss of the DC-DC converter; m represents the total number of fully controlled switches in the DC-DC converter; V S-on I is the first on-state voltage drop of the fully controlled switch in the DC-DC converter; S-rms This is the first effective on-state current; The first switching loss model includes:

[0114] Among them, P S-sw The total switching loss of the DC-DC converter is given by E; k is the number of bridge arms of the DC-DC converter; E on1 For the first single activation loss; E off1 For the first single shutdown loss; f sw1 The first switching frequency; The main power unit loss is the sum of the total conduction loss of all 6-pulse diode rectifier bridges, the total conduction loss of the DC-DC converter, and the total switching loss of the DC-DC converter.

[0115] In some embodiments, the second fully controlled switch conduction loss model includes:

[0116] Among them, P IGBT-cond denoted as the total conduction loss of the rectifier; p represents the total number of fully controlled switching transistors in the rectifier. This is the second on-state voltage drop of the fully controlled switch in the rectifier; This is the second effective on-state current; The second switching loss model includes:

[0117] Among them, P S-sw q represents the total switching loss of the rectifier; q represents the number of bridge arms of the rectifier; E on2 For the second single activation loss; E off2 For the second single shutdown loss; f sw2 This is the second switching frequency; The loss of the compensation unit is the sum of the total conduction loss and the total switching loss of the rectifier.

[0118] Specifically, to achieve optimal system efficiency, this embodiment introduces an efficiency optimization step. This step can be triggered during steady-state system operation, and its implementation can be as follows: First, real-time acquisition of system operation data, which may include total output power P out DC bus voltage U dc The actual output power P of the main power unit d-act The actual output power P of the compensation unit ig-act And the operating parameters of each power device. The operating parameters of each power device may include the forward voltage drop V of the rectifier diodes in the 6-pulse diode rectifier bridge. F The first on-state voltage drop V of the fully controlled switch in the DC-DC converter S-on First switching frequency f sw1 First single activation loss E on1 First single turn-off loss E off1 The second on-state voltage drop of the fully controlled switching transistor in the rectifier Second switching frequency f sw2 Second single-time activation loss E on2 Second single-turn-off loss E off2 .

[0119] Next, a power device loss model can be constructed. This model can include a main power unit loss sub-model and a compensation unit loss sub-model. The main power unit loss sub-model can include the rectifier diode conduction loss model of the 6-pulse diode rectifier bridge, the first fully controlled switch conduction loss model of the DC-DC converter, and the first switching loss model. The compensation unit loss sub-model can include the second fully controlled switch conduction loss model of the rectifier and the second switching loss model. These loss models are mathematical models, typically expressed as functions of current, voltage, and switching frequency. Model parameters can be obtained through offline testing or device datasheets.

[0120] The forward voltage drop V of the rectifier diode in the 6-pulse diode rectifier bridge can be reduced. F Average conduction current I D-avg Input to the rectifier diode conduction loss model, output the total conduction loss P of all 6-pulse diode rectifier bridges. D-cond The first on-state voltage drop V of the fully controlled switch in the DC-DC converter can be... S-on First effective conduction current I S-rms Input to the first fully controlled switch conduction loss model, output the total conduction loss P of the DC-DC converter. S-cond The first switching frequency f can be... sw1 First single activation loss E on1 First single turn-off loss Eoff1 Input to the first switching loss model, output the total switching loss P of the DC-DC converter. S-sw P D-cond P S-cond and P S-sw The sum of these values ​​represents the main power unit loss P. loss,diode .

[0121] The second on-state voltage drop of the fully controlled switching transistor in the rectifier can be reduced. Second effective conduction current Input to the second fully controlled switch conduction loss model, output the total conduction loss P of the rectifier. IGBT-cond The second switching frequency f can be... sw2 Second single-time activation loss E on2 Second single-turn-off loss E off2 The input is given to the second switching loss model, and the output is the total switching loss P of the rectifier. S-sw P IGBT-cond P S-sw The sum of these losses is used as the compensation unit loss P. loss,igbt .

[0122] Total system loss P loss It can be the main power unit loss P loss,diode With compensation unit loss P loss,igbt sum.

[0123] Wherein, according to the actual output power P of the power unit d-act With DC bus voltage U dc The average on-state current I of the 6-pulse diode rectifier bridge in the main power unit was calculated. D-avg The specific formula is as follows: .

[0124] Combined with the inductor ripple current of the DC-DC converter The first effective on-state current I of the fully controlled switch in the DC-DC converter is calculated. S-rms The specific formula is as follows: .

[0125] Based on the actual output power P of the compensation unit ig-act With DC bus voltage U dc The average output current I of the compensation unit is calculated. ig-avg The specific formula is as follows: .

[0126] Combined with the ripple current of the AC side inductor of the rectifier in the compensation unit The second effective on-state current of the fully controlled switch in the rectifier was calculated. The specific formula is as follows: .

[0127] In some embodiments, determining the optimal power allocation coefficient based on the total system loss and total output power may, in specific implementation, include: Set an initial power allocation coefficient, and based on the initial power allocation coefficient and the total output power, determine the target fundamental power allocation value and the target compensation power allocation value before the disturbance; Starting from the initial power allocation coefficient, a preset perturbation is applied to obtain the perturbed power allocation coefficient. Based on the perturbed power allocation coefficient and the total output power, the perturbed target fundamental power allocation value and target compensation power allocation value are determined. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device corresponding to the target fundamental power allocation value and the target compensation power allocation value before the disturbance are input into the preset power device loss model, and the total system loss before the disturbance is output. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device are input into the preset power device loss model after the perturbation of the target fundamental power allocation value and the target compensation power allocation value, and the total system loss after the perturbation is output. The difference between the total system loss after the disturbance and the total system loss before the disturbance is calculated to obtain the change in total system loss. If the change in the total system loss is less than zero, it means that the direction of the disturbance reduces the total loss, so the disturbance continues to be applied in the same direction; if the change in the total system loss is greater than zero, it means that the direction of the disturbance increases the total loss, so the disturbance is applied in the opposite direction. Repeat the above steps of applying the disturbance, calculating the total system loss before and after the disturbance, and determining the direction until the change in the total system loss converges to the preset change threshold. Then, take the power allocation coefficient obtained after the disturbance as the optimal power allocation coefficient.

[0128] Specifically, in this embodiment, the method for determining the optimal power allocation coefficient α can be as follows: Set an initial power allocation factor α0, based on the initial power allocation factor and the total output power P. out Determine the target fundamental power P before the disturbance. diode Allocation value α0P out and target compensation power P igbt Allocation value (1-α0) P out +P harm +P reac .

[0129] Starting from the initial power allocation coefficient, a preset perturbation Δα is applied to obtain the perturbed power allocation coefficient. Based on the perturbed power allocation coefficient and the total output power P out Determine the target fundamental power P after perturbation. diode Assignment value and target compensation power P igbt Assignment value .

[0130] The target fundamental power P before the disturbance diode Assigned value and target compensation power P igbt The actual output power P of the main power unit corresponding to the allocated value d-act The actual output power P of the compensation unit ig-act The operating parameters of each power device are input into a preset power device loss model, and the total system loss before the disturbance is output. The perturbed target fundamental power P diode Assigned value and target compensation power P igbt The actual output power P of the main power unit corresponding to the allocated value d-act The actual output power P of the compensation unit ig-act The operating parameters of each power device are input into a preset power device loss model, and the total system loss after disturbance is output. The difference between the total system loss after the disturbance and the total system loss before the disturbance is calculated to obtain the change in total system loss. If the change in the total system loss is less than zero, it means that the direction of the disturbance reduces the total loss, so the disturbance continues to be applied in the same direction; if the change in the total system loss is greater than zero, it means that the direction of the disturbance increases the total loss, so the disturbance is applied in the opposite direction. Repeat the above steps of applying the disturbance, calculating the total system loss before and after the disturbance, and determining the direction until the change in the total system loss converges to the preset change threshold. Then, take the power allocation coefficient obtained after the disturbance as the optimal power allocation coefficient.

[0131] Then, the optimal power allocation coefficient is fed back to the power decomposition stage to correct the allocation ratio between the target fundamental power and the target compensation power.

[0132] It should be noted that the above-mentioned inputting the actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device into the preset power device loss model based on the actual output power of the main power unit and the actual output power of the compensation unit corresponding to the target fundamental power allocation value and the target compensation power allocation value before and after the disturbance, can include: calculating the corresponding average conduction current and effective conduction current according to the above method, and then substituting them together with the operating parameters of each power device into the model to output the total system loss before and after the disturbance. This specification will not elaborate on this.

[0133] The overall workflow of the collaborative control method for an electrolytic hydrogen production hybrid rectification system provided in this embodiment of the invention can be as follows: System initialization: The co-controller completes initialization, setting sampling parameters, PWM parameters, filter parameters, etc.

[0134] Data acquisition: Collect three-phase voltage, three-phase current and DC bus voltage on the power grid side.

[0135] Harmonic and reactive power extraction: Based on the collected grid voltage and current, harmonic current components and reactive current components are extracted.

[0136] Power decomposition: Obtain the total power required by the electrolytic cell and decompose it into target fundamental power (allocated to the main power unit) and target compensation power (allocated to the compensation unit).

[0137] Dynamic coordination (triggered during power mutation): A rate limit is applied to the target fundamental power, and all mutation components are allocated to the target compensation power, so as to achieve priority response of the compensation unit and smooth adjustment of the main power unit.

[0138] Main power control: Based on the target fundamental power and DC bus voltage, a duty cycle command is generated to adjust the actual fundamental power output of the main power unit.

[0139] Compensation control: Based on the target compensation power, harmonic current components and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current, thereby realizing power fluctuation compensation, harmonic suppression and reactive compensation.

[0140] Efficiency optimization (triggered during system steady state): Collect system operation data, calculate the total system loss based on the loss model, determine the optimal power allocation coefficient through a search algorithm, and feed it back to the power decomposition stage to optimize system operating efficiency.

[0141] This specification also provides a cooperative control system, which, in specific implementation, may include: An integrated multi-winding transformer has one input winding and at least three low-voltage output windings; The main power unit has its input terminal connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer. It is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. A compensation unit, the input terminal of which is connected to the third low-voltage output winding of the integrated multi-winding transformer, is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier; and... The cooperative controller is used to execute the cooperative control method described above.

[0142] For specific processing details of the cooperative controller, please refer to the specific embodiments in S101~S104, which will not be elaborated here.

[0143] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. For details, please refer to the foregoing descriptions of the relevant processing embodiments; they will not be repeated here.

[0144] The foregoing description of this method is for illustrative purposes only and describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than those shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0145] Although this specification provides the following examples or appendices Figure 3The method or apparatus structure shown may include more or fewer combined operation steps or module units based on conventional or non-inventive methods. In steps or structures where there is no logically necessary causal relationship, the execution order of these steps or the module structure of the apparatus is not limited to the execution order or module structure shown in the embodiments or drawings of this specification. When the method or module structure is applied in actual devices, servers, or terminal products, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiments or drawings (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed processing or server cluster implementation environment). Based on the above-described collaborative control method for an electrolytic hydrogen production hybrid rectification system, this specification also proposes an embodiment of a collaborative control device for an electrolytic hydrogen production hybrid rectification system. Figure 3 As shown, the device may specifically include the following modules: The extraction module 301 can be used to collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. The decomposition module 302 can be used to obtain the total power required by the electrolytic cell and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit. The main power unit adjustment module 303 can be used to generate a duty cycle command based on the target fundamental power and the voltage of the DC bus, so as to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. The compensation unit control module 304 can be used to generate a total current reference command based on the target compensation power, harmonic current component and reactive current component, so as to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to realize power fluctuation compensation, to cancel the harmonic current component to realize harmonic suppression, and to cancel the reactive current component to realize reactive compensation.

[0146] This specification also provides an electronic device based on the above-described coordinated control method for an electrolytic hydrogen production hybrid rectifier system, including a processor and a memory for storing processor-executable programs / instructions. Specifically, the processor can execute the following steps according to the program / instructions: acquiring the three-phase voltage, three-phase current, and DC bus voltage from the power grid; extracting the harmonic current component and reactive current component from the power grid based on the three-phase voltage and three-phase current; obtaining the total power required by the electrolyzer; and decomposing the total power into a target fundamental power allocated to the main power unit and a target compensation allocated to the compensation unit. Power; Based on the target fundamental power and the voltage of the DC bus, a duty cycle command is generated to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power; Based on the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

[0147] To execute the above instructions more accurately, please refer to... Figure 4 As shown in the embodiments of this specification, another specific electronic device is also provided, wherein the electronic device includes a network communication port 401, a processor 402 and a memory 403, and the above structures are connected by internal cables so that the various structures can perform specific data interaction.

[0148] Specifically, the processor 402 can be used to collect the three-phase voltage and three-phase current of the power grid and the voltage of the DC bus; extract the harmonic current component and reactive current component of the power grid based on the three-phase voltage and three-phase current; obtain the total power required by the electrolytic cell; decompose the total power into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit; generate a duty cycle command based on the target fundamental power and the voltage of the DC bus to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power; and generate a total current reference command based on the target compensation power, harmonic current component, and reactive current component to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to achieve power fluctuation compensation, to offset the harmonic current component to achieve harmonic suppression, and to offset the reactive current component to achieve reactive power compensation. The memory 403 can be used to store the corresponding instruction program.

[0149] In this embodiment, the network communication port 401 can be a virtual port bound to different communication protocols, thereby enabling the sending or receiving of different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, the network communication port can also be a physical communication interface or communication chip. For example, it can be a wireless mobile network communication chip, such as GSM or CDMA; it can also be a Wi-Fi chip; or it can be a Bluetooth chip.

[0150] In this embodiment, the processor 402 can be implemented in any suitable manner. For example, the processor can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. This specification is not limiting.

[0151] In this embodiment, the memory 403 may include multiple layers. In a digital system, anything that can store binary data can be a memory. In an integrated circuit, a circuit with storage function but no physical form is also called a memory, such as RAM, FIFO, etc. In a system, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0152] This specification also provides a computer storage medium based on the above-described collaborative control method for an electrolytic hydrogen production hybrid rectifier system. The computer storage medium stores computer programs / instructions, which, when executed, perform the following: acquiring the three-phase voltage, three-phase current, and DC bus voltage from the power grid; extracting the harmonic current component and reactive current component from the power grid based on the three-phase voltage and current; obtaining the total power required by the electrolyzer; decomposing the total power into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit; and according to the... Based on the target fundamental power and the voltage of the DC bus, a duty cycle command is generated to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. According to the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. This compensation current is used to respond to the power fluctuation portion of the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

[0153] In this embodiment, the storage medium includes, but is not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Cache, Hard Disk Drive (HDD), or Memory Card. The memory can be used to store computer program instructions. The network communication unit can be an interface configured according to standards specified in the communication protocol for network connection communication.

[0154] In this embodiment, the specific functions and effects implemented by the program instructions stored in the computer storage medium can be explained in comparison with other implementation methods, and will not be repeated here.

[0155] This specification also provides a computer program product based on the above-described collaborative control method for an electrolytic hydrogen production hybrid rectifier system. The product includes a non-transient computer-readable storage medium storing computer programs / instructions. These computer programs / instructions are operable to cause the computer to perform the following steps: acquiring three-phase voltage, three-phase current, and the voltage of the DC bus from the grid side; extracting harmonic current components and reactive current components from the grid side based on the three-phase voltage and three-phase current; obtaining the total power required by the electrolyzer; and decomposing the total power into a target fundamental power allocated to the main power unit and a target compensation power allocated to the compensation unit. The system generates a duty cycle command based on the target fundamental power and the voltage of the DC bus to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. It also generates a total current reference command based on the target compensation power, harmonic current components, and reactive current components to control the compensation unit to output compensation current to the DC bus. This compensation current is used to respond to the power fluctuation portion of the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

[0156] While this specification provides the steps of operation for the methods described in the embodiments or flowcharts, more or fewer steps may be included based on conventional or non-inventive means. The order of steps listed in the embodiments is merely one possible order of execution among many steps and does not represent the only possible order. In actual device or client product execution, the methods shown in the embodiments or drawings may be executed sequentially or in parallel (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitations, the presence of other identical or equivalent elements in a process, method, product, or apparatus that includes said elements is not excluded. The terms "first," "second," etc., are used to denote names and do not indicate any particular order.

[0157] Those skilled in the art will also know that, besides implementing the controller using purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0158] This specification can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc., that perform a specific task or implement a specific abstract data type. This specification can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0159] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this specification can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of this specification can essentially be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, mobile terminal, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments of this specification.

[0160] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. This specification can be used in numerous general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable electronic devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices, etc.

[0161] Although this specification has been described by way of examples, those skilled in the art will recognize that many variations of this specification are possible without departing from its spirit, and it is intended that the appended claims cover such variations without departing from the spirit of this specification.

Claims

1. A collaborative control method for an electrolytic hydrogen production hybrid rectification system, characterized in that, The electrolytic hydrogen production hybrid rectification system includes a main power unit and a compensation unit. The output terminals of both the main power unit and the compensation unit are connected to a DC bus supplying power to the electrolyzer. The method includes: Collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. Obtain the total power required by the electrolytic cell, and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit; Based on the target fundamental power and the voltage of the DC bus, a duty cycle command is generated to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. Based on the target compensation power, harmonic current components, and reactive current components, a total current reference command is generated to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation portion of the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current components to achieve harmonic suppression, and to cancel the reactive current components to achieve reactive power compensation.

2. The collaborative control method according to claim 1, characterized in that, The electrolytic hydrogen production hybrid rectification system also includes an integrated multi-winding transformer, which has one input winding and at least three low-voltage output windings. The input winding is connected to the grid side and is used to transform the AC power from the grid side and distribute it to each low-voltage output winding. The input terminal of the main power unit is connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. The input terminal of the compensation unit is connected to the third low-voltage output winding of the integrated multi-winding transformer, and is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier. The duty cycle command is used to regulate the switching of the DC-DC converter to adjust the actual fundamental power output by the main power unit to the DC bus, and the total current reference command is used to control the rectifier to output compensation current to the DC bus.

3. The collaborative control method according to claim 1, characterized in that, The extraction of harmonic current components and reactive current components from the grid side based on the three-phase voltage and three-phase current includes: The three-phase voltage and three-phase current are transformed to the αβ stationary coordinate system to obtain the voltage component along the α axis, the voltage component along the β axis, the current component along the α axis, and the current component along the β axis. Calculate the instantaneous active power and instantaneous reactive power based on the voltage component of the α-axis, the voltage component of the β-axis, the current component of the α-axis, and the current component of the β-axis. The DC components of instantaneous active power and instantaneous reactive power are extracted by using a low-pass filter. Subtracting the DC component of the instantaneous active power from the instantaneous active power yields the AC component of the instantaneous active power; subtracting the DC component of the instantaneous reactive power from the instantaneous reactive power yields the AC component of the instantaneous reactive power. The harmonic current components are obtained by performing two inverse transformations on the AC components of instantaneous active power and instantaneous reactive power. Calculate the reactive current component based on the DC component of the instantaneous reactive power.

4. The collaborative control method according to claim 3, characterized in that, The process of performing two inverse transformations on the AC components of instantaneous active power and instantaneous reactive power to obtain harmonic current components includes: The AC components of instantaneous active power and instantaneous reactive power are transformed by the first inverse transformation to obtain the harmonic current components of the α-axis and the β-axis in the αβ stationary coordinate system. The harmonic current components along the α-axis and β-axis are subjected to a second inverse transformation to obtain the three-phase harmonic current components. The instantaneous values ​​of the three-phase harmonic current components are taken as the harmonic current components. The calculation of the reactive current component based on the DC component of the instantaneous reactive power includes: The reactive current component is determined based on the ratio of the DC component of the instantaneous reactive power to the grid voltage amplitude, wherein the grid voltage amplitude is determined based on the three-phase voltage on the grid side. The first inverse transformation is a transformation from power quantity to current quantity in the αβ stationary coordinate system, and the second inverse transformation is a Clarke inverse transformation from the αβ stationary coordinate system to the abc three-phase coordinate system.

5. The collaborative control method according to claim 1, characterized in that, The step of decomposing the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit includes: The total power is low-pass filtered, and the slow-changing DC component obtained after filtering is taken as the target fundamental power, which is the main power component for hydrogen production in the electrolyzer. The difference between the total power and the target fundamental power is taken as the power fluctuation component; Harmonic compensation components are generated based on the harmonic current components, and reactive compensation components are generated based on the reactive current components. The power fluctuation component, harmonic compensation component, and reactive power compensation component are combined to form the target compensation power, which is the auxiliary compensation power component for hydrogen production power supply in the electrolyzer.

6. The cooperative control method according to claim 1, characterized in that, The step of generating a duty cycle command based on the target fundamental power and the DC bus voltage includes: The target output current of the DC converter in the main power unit is determined based on the ratio of the target fundamental power to the voltage of the DC bus. Collect the actual output current of the DC-DC converter in the main power unit, and calculate the first current error between the target output current and the actual output current of the DC-DC converter. The duty cycle adjustment is calculated based on the first current error and the first proportional coefficient and first integral coefficient of the regulator. The first proportional coefficient and first integral coefficient are set according to the inductance value, switching frequency and desired current loop cutoff frequency of the DC converter. The feedforward duty cycle is determined based on the ratio of the voltage of the DC bus to the average voltage output of the two 6-pulse diode rectifier bridges in the main power unit. The duty cycle adjustment amount and the feedforward duty cycle are superimposed to obtain the initial duty cycle, and the initial duty cycle is limited to a preset range to generate a duty cycle command.

7. The cooperative control method according to claim 6, characterized in that, The step of calculating the duty cycle adjustment based on the first current error and preset first proportional coefficient and first integral coefficient includes: Calculate the duty cycle adjustment amount using the following formula: in, This is the duty cycle adjustment amount; This is the first proportional system; e is the first integral coefficient; I This is the first current error.

8. The cooperative control method according to claim 1, characterized in that, The step of generating a total current reference command based on the target compensation power, harmonic current components, and reactive current components includes: Based on the power fluctuation component in the target compensation power, an active current command for the d-axis in the dq rotating coordinate system is generated. Take the opposite phase of the reactive current component to generate a reactive current command for the q-axis in the dq rotating coordinate system; Take the opposite phase of the harmonic current component to generate a three-phase harmonic current command in the abc three-phase coordinate system; The active current command and reactive current command are sequentially subjected to the third inverse transformation and the second inverse transformation, and then superimposed with the three-phase harmonic current command to synthesize the total current reference command in the abc three-phase coordinate system. The third inverse transformation is the Park inverse transformation from the dq rotating coordinate system to the αβ stationary coordinate system.

9. The cooperative control method according to claim 8, characterized in that, The step of generating an active current command along the d-axis in the dq rotating coordinate system based on the power fluctuation component in the target compensation power includes: The active current command along the d-axis in the dq rotating coordinate system is generated according to the following formula: in, This is the active current command for the d-axis in the dq rotating coordinate system; P wave For power fluctuation components; U d Let be the grid voltage along the d-axis in the dq rotating coordinate system, and its value is equal to the grid voltage amplitude. The process of sequentially performing a third inverse transformation and a second inverse transformation on the active current command and the reactive current command, and then superimposing them with the three-phase harmonic current command to synthesize a total current reference command in the abc three-phase coordinate system, includes: The active current command and reactive current command are transformed by the third inverse transformation to obtain the fundamental current command of the α axis and the fundamental current command of the β axis in the αβ stationary coordinate system. The fundamental current command of the α-axis and the fundamental current command of the β-axis are transformed by a second inverse transformation to obtain the three-phase fundamental current command in the abc three-phase coordinate system. The three-phase fundamental current command and the three-phase harmonic current command are superimposed to obtain the total current reference command in the abc three-phase coordinate system.

10. The cooperative control method according to claim 1, characterized in that, The control of the compensation unit to output compensation current to the DC bus includes: Calculate the voltage feedforward term based on the three-phase voltage and three-phase current on the grid side and the AC side inductance of the rectifier in the compensation unit; The actual AC output current of the rectifier in the compensation unit is collected, and the second current error between the total reference current in the total current reference command and the actual AC output current of the rectifier is calculated. The current feedback correction is calculated based on the second current error and the second proportional coefficient and second integral coefficient of the regulator. The second proportional coefficient and second integral coefficient are set according to the inductance value of the rectifier, the switching frequency and the desired current loop cutoff frequency. The voltage feedforward term is added to the current feedback correction to obtain a pulse width modulation wave signal; Based on the pulse width modulation wave signal, the switching transistor of the rectifier in the compensation unit is controlled to turn on and off, so that the compensation unit outputs compensation current to the DC bus.

11. The cooperative control method according to claim 1, characterized in that, The method further includes: A rate limit is applied to the target fundamental power so that the rate of change of the target fundamental power is less than a preset rate threshold, but no rate limit is applied to the target compensation power; When a sudden change in the total power is detected, the sudden change component is allocated to the target compensation power, so that the compensation unit generates a corresponding compensation current according to the sudden change component to make up for the power deficit. At the same time, the actual fundamental power of the main power unit approaches the target fundamental power at a limited rate until the total power stops changing.

12. The cooperative control method according to claim 1, characterized in that, The method further includes: The system collects real-time operating data, including the inductor ripple current of the DC converter, the ripple current of the AC side inductor of the rectifier in the compensation unit, and the operating parameters of each power device. The system operating data includes the total output power, DC bus voltage, actual output power of the main power unit, and actual output power of the compensation unit. Based on the actual output power of the power unit and the DC bus voltage, the average on-state current of the 6-pulse diode rectifier bridge in the main power unit is calculated, and combined with the inductor ripple current of the DC converter, the first effective on-state current of the fully controlled switch in the DC converter is calculated. Based on the actual output power of the compensation unit and the DC bus voltage, the average output current of the compensation unit is calculated, and combined with the ripple current of the AC side inductor of the rectifier of the compensation unit, the second effective conduction current of the fully controlled switch in the rectifier is calculated. The collected operating parameters of each power device, as well as the average on-state current, the first effective on-state current, and the second effective on-state current, are input into a preset power device loss model, and the total system loss is output. The total system loss is the sum of the main power unit loss and the compensation unit loss. Based on the total system loss, total output power, and DC bus voltage, an optimal power allocation coefficient is determined. This optimal power allocation coefficient is used to dynamically adjust the allocation ratio between the target fundamental power and the target compensation power so that the total system loss is less than a preset loss threshold. The operating parameters of each power device include the forward voltage drop of the rectifier diode in the 6-pulse diode rectifier bridge; the first on-state voltage drop, first switching frequency, first single turn-on loss, and first single turn-off loss of the fully controlled switch in the DC converter; and the second on-state voltage drop, second switching frequency, second single turn-on loss, and second single turn-off loss of the fully controlled switch in the rectifier.

13. The cooperative control method according to claim 12, characterized in that, The power device loss model includes a main power unit loss sub-model and a compensation unit loss sub-model. The main power unit loss sub-model includes the rectifier diode conduction loss model of the 6-pulse diode rectifier bridge, the first fully controlled switch conduction loss model and the first switching loss model of the DC converter. The compensation unit loss sub-model includes the second fully controlled switch conduction loss model and the second switching loss model of the rectifier. The rectifier diode conduction loss model includes: Among them, P D-cond V represents the total conduction loss of all 6-pulse diode rectifier bridges; n represents the total number of rectifier diodes in all 6-pulse diode rectifier bridges; V F I represents the forward voltage drop of the rectifier diodes in a 6-pulse diode rectifier bridge. D-avg This represents the average on-state current. The first fully controlled switch conduction loss model includes: Among them, P S-cond V represents the total conduction loss of the DC-DC converter; m represents the total number of fully controlled switches in the DC-DC converter; V S-on I is the first on-state voltage drop of the fully controlled switch in the DC-DC converter; S-rms This is the first effective on-state current; The first switching loss model includes: Among them, P S-sw The total switching loss of the DC-DC converter is given by E; k is the number of bridge arms of the DC-DC converter; E on1 For the first single activation loss; E off1 For the first single shutdown loss; f sw1 The first switching frequency; The main power unit loss is the sum of the total conduction loss of all 6-pulse diode rectifier bridges, the total conduction loss of the DC-DC converter, and the total switching loss of the DC-DC converter.

14. The cooperative control method according to claim 13, characterized in that, The second fully controlled switch conduction loss model includes: Among them, P IGBT-cond denoted as the total conduction loss of the rectifier; p represents the total number of fully controlled switching transistors in the rectifier. This is the second on-state voltage drop of the fully controlled switch in the rectifier; This is the second effective on-state current; The second switching loss model includes: Among them, P S-sw q represents the total switching loss of the rectifier; q represents the number of bridge arms of the rectifier; E on2 For the second single activation loss; E off2 For the second single shutdown loss; f sw2 This is the second switching frequency; The loss of the compensation unit is the sum of the total conduction loss and the total switching loss of the rectifier.

15. The cooperative control method according to claim 12, characterized in that, The determination of the optimal power allocation coefficient based on the total system loss and total output power includes: Set an initial power allocation coefficient, and based on the initial power allocation coefficient and the total output power, determine the target fundamental power allocation value and the target compensation power allocation value before the disturbance; Starting from the initial power allocation coefficient, a preset perturbation is applied to obtain the perturbed power allocation coefficient. Based on the perturbed power allocation coefficient and the total output power, the perturbed target fundamental power allocation value and target compensation power allocation value are determined. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device corresponding to the target fundamental power allocation value and the target compensation power allocation value before the disturbance are input into the preset power device loss model, and the total system loss before the disturbance is output. The actual output power of the main power unit, the actual output power of the compensation unit, and the operating parameters of each power device are input into the preset power device loss model after the perturbation of the target fundamental power allocation value and the target compensation power allocation value, and the total system loss after the perturbation is output. The difference between the total system loss after the disturbance and the total system loss before the disturbance is calculated to obtain the change in total system loss. If the change in the total system loss is less than zero, it means that the direction of the disturbance reduces the total loss, so the disturbance continues to be applied in the same direction; if the change in the total system loss is greater than zero, it means that the direction of the disturbance increases the total loss, so the disturbance is applied in the opposite direction. Repeat the above steps of applying the disturbance, calculating the total system loss before and after the disturbance, and determining the direction until the change in the total system loss converges to the preset change threshold. Then, take the power allocation coefficient obtained after the disturbance as the optimal power allocation coefficient.

16. A cooperative control system, characterized in that, include: An integrated multi-winding transformer has one input winding and at least three low-voltage output windings; The main power unit has its input terminal connected to the first low-voltage output winding and the second low-voltage output winding of the integrated multi-winding transformer. It is used to rectify the transformed AC power into DC power and output it to the DC bus. The main power unit includes at least two 6-pulse diode rectifier bridges and a DC converter connected in series with the output terminals of the two 6-pulse diode rectifier bridges. The compensation unit has its input terminal connected to the third low-voltage output winding of the integrated multi-winding transformer. It is used to rectify the transformed AC power into DC power and provide compensation current to the DC bus. The compensation unit includes a rectifier. as well as, A cooperative controller for performing the cooperative control method as described in any one of claims 1 to 15.

17. A collaborative control device for an electrolytic hydrogen production hybrid rectification system, characterized in that, The electrolytic hydrogen production hybrid rectification system includes a main power unit and a compensation unit. The output terminals of both the main power unit and the compensation unit are connected to a DC bus supplying power to the electrolyzer. The device includes: The extraction module is used to collect the three-phase voltage, three-phase current and DC bus voltage on the grid side, and extract the harmonic current component and reactive current component on the grid side based on the three-phase voltage and three-phase current. The decomposition module is used to obtain the total power required by the electrolytic cell and decompose the total power into the target fundamental power allocated to the main power unit and the target compensation power allocated to the compensation unit. The main power unit adjustment module is used to generate a duty cycle command based on the target fundamental power and the voltage of the DC bus, so as to adjust the actual fundamental power output by the main power unit to the DC bus, so that the actual fundamental power matches the target fundamental power. The compensation unit control module is used to generate a total current reference command based on the target compensation power, harmonic current component, and reactive current component, so as to control the compensation unit to output compensation current to the DC bus. The compensation current is used to respond to the power fluctuation part in the target compensation power to achieve power fluctuation compensation, to cancel the harmonic current component to achieve harmonic suppression, and to cancel the reactive current component to achieve reactive power compensation.

18. An electronic device, characterized in that, include: A memory and a processor, the processor and the memory being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to implement the steps of the method according to any one of claims 1 to 15.

19. A computer storage medium, characterized in that, The computer storage medium stores computer program instructions, which, when executed, implement the steps of the method according to any one of claims 1 to 15.

20. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 15.

Images