Hydrogen production power supply system for producing hydrogen by electrolyzing water

Abstract

The utility model provides a hydrogen production power supply system for producing hydrogen by electrolyzing water, which realizes wide power output range, automatic voltage division and current sharing, current ripple reduction and filter capacitance reduction on the basis of a three-phase LLC (Logical Link Control) converter module. The three-phase LLC converter module comprises a primary side inversion network, a resonance network, a high-frequency transformer, a rectification network and a filtering unit, wherein the front end of the primary side inversion network is provided with a filtering electrolytic capacitor for filtering an input DC voltage; the primary side inverter network adopts a three-phase conversion circuit structure, and inputs high-voltage direct-current voltage; the primary side inverter network converts direct current voltage into alternating current through DC-AC conversion, and the alternating current side of the primary side inverter network is directly or indirectly connected with the primary side of the high-frequency transformer correspondingly through the resonance network; the secondary side of the high-frequency transformer is correspondingly connected with the rectification network, and the output end of the rectification network is connected with the filtering unit.

Description

Technical Field

[0001] This utility model relates to the field of hydrogen production technology through water electrolysis, specifically a hydrogen production power supply system for hydrogen production through water electrolysis. Background Technology

[0002] Hydrogen energy, as a clean and efficient secondary energy source, has wide applications in transportation, industry, and energy storage. Among these, hydrogen production through water electrolysis is considered an important direction for future renewable energy development due to its advantages such as zero carbon emissions and high-purity hydrogen production.

[0003] In the process of hydrogen production through water electrolysis, the electrolyzer requires a stable, high-current input and has strict requirements on current ripple to ensure electrolysis efficiency and stable hydrogen production. However, traditional unidirectional LLC resonant converters exhibit large output current ripple in high-power applications, necessitating the addition of numerous filter capacitors to reduce the ripple amplitude. This not only increases the size and cost of the converter but also reduces the overall lifespan of the converter system due to the limited lifespan of the filter capacitors. Therefore, existing unidirectional LLC solutions are insufficient to meet the long-term stability requirements of high-power water electrolysis for hydrogen production.

[0004] In response to the above issues, the industry has raised higher requirements for hydrogen production power systems, including:

[0005] Low current ripple: Reduces reliance on filter capacitors, improving system reliability and lifespan.

[0006] High conversion efficiency: Reduces power loss and improves hydrogen production efficiency.

[0007] Stable output: Ensures that the electrolytic cell can obtain a stable current input under different load conditions.

[0008] Modular design: adapts to hydrogen production needs of different power levels, enabling flexible expansion.

[0009] To meet the above requirements, a power supply topology that can effectively reduce current ripple, improve system conversion efficiency, and have good stability is needed to adapt to the high-power, long-life application scenarios of water electrolysis for hydrogen production. Summary of the Invention

[0010] To overcome a series of defects in existing technologies, the purpose of this utility model is to provide a hydrogen production power supply system for water electrolysis to produce hydrogen. Based on a three-phase LLC converter module, it achieves a wide power output range, automatic voltage division and current sharing, reduced current ripple, and reduced filter capacitors. The three-phase LLC converter module includes: a primary-side inverter network, a resonant network, a high-frequency transformer, a rectifier network, and a filter unit. Specifically: the primary-side inverter network is equipped with a filter electrolytic capacitor at its front end to filter the input DC voltage; the primary-side inverter network adopts a three-phase conversion circuit structure, with a high-voltage DC input; the primary-side inverter network converts the DC voltage to AC voltage through DC-AC conversion, and its AC side is directly or indirectly connected to the primary side of the high-frequency transformer through the resonant network; the secondary side of the high-frequency transformer is connected to the rectifier network, and the output of the rectifier network is connected to the filter unit.

[0011] Preferably, the resonant network includes a resonant inductor, a resonant capacitor, and a magnetizing inductor, wherein the magnetizing inductor is provided by the leakage inductance of the high-frequency transformer and is directly integrated into the transformer; the resonant inductor and the resonant capacitor are connected in series.

[0012] Preferably, the high-frequency transformer adopts a phase-splitting design, with each phase using a series-parallel structure of two small transformers. Specifically, each phase transformer on the inverter side adopts a structure of two transformers connected in series on the primary side and in parallel on the secondary side.

[0013] Preferably, the filter unit consists of six electrolytic capacitors connected in parallel.

[0014] Preferably, the rectifier network adopts a parallel structure of two rectifier bridges to achieve a wide range of adjustment of the output current.

[0015] Preferably, the rectifier bridge consists of six fast recovery diodes.

[0016] Preferably, the three-phase LLC converter modules are configured as three, and the three three-phase LLC converter modules are connected in parallel and then connected to a parallel switching circuit.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The three-phase LLC converter module in this invention not only achieves automatic voltage and current sharing across phases, but also enables the switching transistors to achieve zero-voltage turn-on (ZVS) and the secondary rectifier diodes to achieve zero-current turn-off (ZCS) over a wide voltage and load range, thereby significantly improving converter efficiency. The primary side of the converter adopts a design with two transformers connected in series on the primary side and in parallel on the secondary side for each phase. This effectively enhances the main circuit's ability to withstand input voltage, while simultaneously reducing the current stress on the secondary rectifier diodes through the parallel connection of the transformer secondary sides. This topology also effectively reduces the size of the main circuit. Its secondary rectifier network uses a parallel design of two rectifier bridges, achieving a wide range of output current adjustment to meet the stringent requirements of hydrogen production power supplies for output ripple current. To adapt to the power supply needs of hydrogen production at different power levels, this converter supports modular design and can adopt a three-module parallel architecture, flexibly responding to various power application scenarios through parallel switching circuits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the circuit structure of the three-phase LLC converter module in an embodiment of this utility model;

[0020] Figure 2 This is a schematic diagram of the circuit structure of a hydrogen production power supply system for producing hydrogen by water electrolysis, as disclosed in an embodiment of this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some embodiments of this utility model, not all embodiments.

[0022] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0023] The embodiments and directional terms described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] In a broad embodiment of this utility model, a hydrogen production power supply system for electrolytic water hydrogen production achieves a wide power output range, automatic voltage division and current sharing, reduced current ripple, and reduced filter capacitors based on a three-phase LLC converter module. The three-phase LLC converter module includes: a primary-side inverter network, a resonant network, a high-frequency transformer, a rectifier network, and a filter unit. Specifically: the primary-side inverter network is equipped with a filter electrolytic capacitor at its front end to filter the input DC voltage; the primary-side inverter network adopts a three-phase converter circuit structure, with a high-voltage DC input; the primary-side inverter network converts the DC voltage to AC voltage through DC-AC conversion, and its AC side is directly or indirectly connected to the primary side of the high-frequency transformer through the resonant network; the secondary side of the high-frequency transformer is connected to the rectifier network, and the output of the rectifier network is connected to the filter unit.

[0025] Preferably, the resonant network includes a resonant inductor, a resonant capacitor, and a magnetizing inductor, wherein the magnetizing inductor is provided by the leakage inductance of the high-frequency transformer and is directly integrated into the transformer; the resonant inductor and the resonant capacitor are connected in series.

[0026] Preferably, the high-frequency transformer adopts a phase-splitting design, with each phase using a series-parallel structure of two small transformers. Specifically, each phase transformer on the inverter side adopts a structure of two transformers connected in series on the primary side and in parallel on the secondary side.

[0027] Preferably, the filter unit consists of six electrolytic capacitors connected in parallel.

[0028] Preferably, the rectifier network adopts a parallel structure of two rectifier bridges to achieve a wide range of adjustment of the output current.

[0029] Preferably, the rectifier bridge consists of six fast recovery diodes.

[0030] Preferably, the three-phase LLC converter modules are configured as three, and the three three-phase LLC converter modules are connected in parallel and then connected to a parallel switching circuit.

[0031] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, and the present invention will be further described in detail.

[0032] This embodiment uses a single-module three-phase LLC resonant converter as an example to detail its structure and principle. Then, three modules of the three-phase LLC converter are connected in parallel to form a power supply system. The single-module structure and principle are as follows: Figure 1 As shown, the structure and principle of the three-module parallel power supply system are as follows: Figure 2 As shown:

[0033] like Figure 1 The transformer secondary rectifier parallel three-phase LLC resonant converter circuit topology shown is mainly divided into four parts:

[0034] The primary-side inverter network consists of two switching transistors per phase. The PWM drive pulses of these transistors control the three bridge arms to shift phase by 120 degrees sequentially. To prevent interconnection between the switching transistors in each bridge arm and potential damage, the upper and lower transistors in each bridge arm are designed to be 180 degrees out of phase. To improve the converter's power density, a duty cycle of 0.5 is chosen. The entire inverter network consists of six switching transistors. In the actual circuit, because each switching transistor has a body diode, the resonant converter achieves soft-switching characteristics precisely by utilizing the voltage clamping effect of the body diode when it is conducting.

[0035] Resonant network: The resonant parameters of each phase of the three-phase LLC are basically the same. The resonant network mainly includes resonant inductor, resonant capacitor and magnetizing inductor. The magnetizing inductor is integrated in the high-frequency transformer and the leakage inductance of the high-frequency transformer is used as the magnetizing inductor in the resonant network. The resonant capacitor plays the role of blocking DC and passing AC.

[0036] High-frequency transformer: Each phase consists of two high-frequency transformers, which reduce the size of the main circuit by using the series and parallel combination of two small transformers.

[0037] Rectifier network: It adopts a parallel structure of two rectifier bridges, which can adjust the output current over a wide range. The rectifier diodes are Schottky diodes with short reverse recovery time.

[0038] Filtering Unit: Electrolytic capacitors are used for filtering. In high-current and high-power applications, this topology can improve the ripple of the output current, thereby reducing the use of filter capacitors and lowering costs.

[0039] The interleaved parallel connection of the three-phase LLC converter can reduce the current ripple rate, thereby reducing the filter capacitor at the output of the three-phase LLC. This three-phase LLC converter uses electrolytic capacitors, which reduces costs, reduces the size of the entire power circuit, and extends the life of the converter.

[0040] This three-phase LLC resonant converter not only enables automatic current sharing and high current output in three phases, but also has significant advantages in reducing output current ripple ratio and electrical isolation. It can be designed with multiple modules in parallel to meet the needs of hydrogen production through water electrolysis in new energy applications with different power levels, and has practical engineering value.

[0041] Figure 2 The system employs a three-module parallel structure to meet the needs of hydrogen production applications in new energy water electrolysis at different power levels. Each module can share power to ensure the conversion efficiency of the entire power system. The output terminals of each module are connected to a parallel switching circuit, and a droop control strategy is used to ensure that maximum power is achieved. When the power required by the electrolyzer is small, the parallel switching circuit can control a single module to work, thereby improving the efficiency of the entire power supply and ensuring stable operation. When the power required by the electrolyzer is large, the parallel switching circuit starts all three modules to operate simultaneously, maintaining a stable output voltage while increasing power.

[0042] The multi-module parallel structure provides users with more options and adapts to various power applications. This hydrogen production power supply system has stable output, low voltage and current ripple, and practical engineering value.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A hydrogen production power supply system for water electrolysis to produce hydrogen, characterized by achieving a wide power output range, automatic voltage division and current sharing, reduced current ripple, and reduced filter capacitors based on a three-phase LLC converter module, wherein... The three-phase LLC converter module includes: a primary-side inverter network, a resonant network, a high-frequency transformer, a rectifier network, and a filter unit. Specifically: the primary-side inverter network is equipped with an electrolytic capacitor at its front end to filter the input DC voltage; the primary-side inverter network adopts a three-phase converter circuit structure, with a high-voltage DC input; the primary-side inverter network converts the DC voltage to AC voltage via DC-AC conversion, and its AC side is directly or indirectly connected to the primary side of the high-frequency transformer via the resonant network; the secondary side of the high-frequency transformer is connected to the rectifier network, and the output of the rectifier network is connected to the filter unit.

2. A hydrogen production power supply system for hydrogen production by water electrolysis according to claim 1, characterized in that, The resonant network includes a resonant inductor, a resonant capacitor, and a magnetizing inductor. The magnetizing inductor is provided by the leakage inductance of the high-frequency transformer and is directly integrated into the transformer. The resonant inductor and the resonant capacitor are connected in series.

3. A hydrogen production power supply system for water electrolysis to produce hydrogen according to claim 1, characterized in that, The high-frequency transformer adopts a phase-splitting design, with each phase using two small transformers connected in series and parallel. Specifically, each phase transformer on the inverter side uses two transformers connected in series on the primary side and in parallel on the secondary side.

4. A hydrogen production power supply system for water electrolysis to produce hydrogen according to claim 1, characterized in that, The filter unit consists of six electrolytic capacitors connected in parallel.

5. A hydrogen production power supply system for water electrolysis to produce hydrogen according to claim 1, characterized in that, The rectifier network adopts a parallel structure of two rectifier bridges to achieve a wide range of adjustment of the output current.

6. A hydrogen production power supply system for hydrogen production by water electrolysis according to claim 5, characterized in that, The rectifier bridge consists of six fast recovery diodes.

7. A hydrogen production power supply system for hydrogen production by water electrolysis according to any one of claims 1-6, characterized in that, The three-phase LLC converter module is configured as three, and the three three-phase LLC converter modules are connected in parallel and then connected to a parallel switching circuit.

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