Hydrogen production system

Abstract

A hydrogen production system (1) comprises a first renewable power source (3-1), a first electrolysis cell (7-1), and a single stage power converter (5) having an input side (5a) and an output side (5b), where the input side (5a) is connected to the first renewable power source (3-1) and the output side (5b) is connected to the first electrolysis cell (7-1).

Description

Technical Field

[0001] The present disclosure generally relates to hydrogen production systems. Background Art

[0002] The hydrogen economy has become an increasingly popular topic. There is consensus that green hydrogen production is the only way to make such an economy prosper. Today, around 95% of hydrogen production is classified as grey, meaning it comes directly from fossil fuel sources and is a carbon dioxide (CO2) intensive activity. Blue hydrogen complements the carbon storage of current production methods, significantly reducing the CO2 footprint. However, green hydrogen produced by electrolysis with renewable energy is the only way to produce hydrogen sustainably.

[0003] To meet the demand for hydrogen, large-scale electrolyzer plants are planned to be deployed in the near future.

[0004] Conventional ways of integrating renewable energy with the power grid and electrolyzers typically require a relatively large physical footprint. Summary of the invention

[0005] In view of the above, a general object of the present disclosure is to provide a hydrogen production system that solves or at least alleviates the problems of the prior art.

[0006] Therefore, a hydrogen production system is provided, comprising: a first renewable power source, a first electrolyser, and a single-stage power converter having an input side and an output side, wherein the input side is connected to the first renewable power source and the output side is connected to the first electrolyser.

[0007] The single-stage power converter is compact and requires less material to connect renewable energy to the electrolyser.

[0008] The output side of a single-stage power converter is the DC side.

[0009] According to one embodiment, the single-stage power converter is a multi-level converter.

[0010] A multilevel converter has at least 2 levels, such as at least 3 levels.

[0011] According to one embodiment, the output side comprises a positive voltage terminal, a neutral terminal and a negative voltage terminal.Thus, the single-stage power converter may be at least a three-level converter.

[0012] According to one embodiment, the electrolytic cell is connected to a positive voltage terminal and a negative voltage terminal.

[0013] The electrolytic cell may have a positive terminal connected to the positive voltage terminal and a negative terminal connected to the negative voltage terminal.

[0014] According to one embodiment, a hydrogen production system includes a second electrolyzer, wherein the first electrolyzer is connected to a positive voltage terminal and a neutral terminal, and wherein the second electrolyzer is connected to a neutral terminal and a negative voltage terminal.

[0015] According to one embodiment, the multilevel converter comprises a three-level active neutral point clamped (ANPC) converter.

[0016] According to one embodiment, the multilevel converter comprises a multi-port hybrid NPC converter.

[0017] According to one embodiment, a multi-port hybrid NPC converter has a first grid-side terminal connected to a power grid.

[0018] Hence, in addition to the first renewable energy source, the multi-port hybrid NPC is also connected to the grid.

[0019] According to one embodiment, the first renewable power source is configured to generate three-phase alternating current, wherein a third branch of the three branches forms a second grid-side terminal connected to the power grid.

[0020] According to one embodiment, the first branch is an intermediate branch relative to the second branch and the third branch.

[0021] One embodiment includes a second renewable power source, wherein the first renewable power source and the second renewable power source are configured to generate direct current, wherein a third branch of the three branches is connected to the second renewable power source, and wherein the second branch is an intermediate branch relative to the first branch and the third branch.

[0022] According to one embodiment, the first branch and the third branch are each provided with one of the first diode and the second diode.

[0023] According to one embodiment, the cathode side of the first diode is connected to the first renewable power source and the anode side of the second diode is connected to the second renewable power source.

[0024] In general, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. Unless explicitly stated otherwise, all references to "an / an / element, device, component, means, etc." should be publicly interpreted as referring to at least one instance of an element, device, component, means, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Specific embodiments of the inventive concept will now be described by way of example with reference to the accompanying drawings, in which:

[0026] Figure 1 A block diagram of a hydrogen production system is schematically shown;

[0027] Figure 2 schematically illustrates an example of a hydrogen production system including a plurality of power converters and electrolyzers connected via a DC bus;

[0028] Figure 3 is an example of a single-stage power converter with renewable power source and electrolyzer connections;

[0029] Figures 4 to 5 An example of a single-stage power converter with renewable power source and electrolyzer connections is shown;

[0030] Figure 6 An example of a single-stage power converter with renewable power source and electrolyzer connections is depicted;

[0031] Figure 7 An example of a single-stage power converter with a renewable power source, an electrolyzer, and a grid connection is depicted;

[0032] Figure 8 Another example of a single-stage power converter having a renewable power source, an electrolyzer, and a grid connection is depicted; and

[0033] Fig. 9 Yet another example of a single-stage power converter having a renewable power source, an electrolyser, and a grid connection is shown; DETAILED DESCRIPTION

[0034] The inventive concept will now be described more fully below with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the inventive concept may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of the inventive concept to those skilled in the art. Throughout the description, the same reference numerals refer to the same elements.

[0035] Figure 1 An example of a hydrogen production system 1 is shown. The hydrogen production system 1 includes a first renewable power source 3-1, a single-stage power converter 5, and a first electrolyzer 7-1.

[0036] The first renewable power source 3-1 may be an AC power source, such as a wind turbine or a wind farm. The AC power source may be multi-phase, such as a three-phase AC power source. Alternatively, the first renewable power source may be a DC power source, such as a photovoltaic power source.

[0037] The single-stage power converter 5 is a multi-level converter. In particular, the single-stage power converter 5 is an n-level converter, wherein n is an integer at least equal to 2. For example, n may be 2, 3, 4 or 5, and so on.

[0038] The single-stage power converter 5 has an input side 5 a connected to the first renewable power source 3 - 1 .

[0039] If the renewable power source 3 - 1 is an AC power source, the input side 5 a is an AC side.

[0040] If the first renewable power source 3 - 1 is a DC power source, the input side 5 b is a DC side.

[0041] The single-stage power converter 5 has an output side 5b connected to the first electrolytic cell 7-1. The output side 5b is a DC side configured to supply power to the first electrolytic cell 7-1.

[0042] If the first renewable power source 3-1 is an AC power source, the single-stage power converter 5 includes a rectifier. If the first renewable power source is a DC power source, the single-stage power converter 5 includes a DC / DC converter.

[0043] The single-stage power converter 5 may include a plurality of controllable switches for controlling the power flow between the input side 5a and the output side 5b. The switches may be transistors, such as insulated gate bipolar transistors (IGBTs) or metal oxide semiconductor field effect transistors (MOS-FETs), for example.

[0044] The hydrogen production system 1 may include a control system (not shown) configured to control the switching of the single-stage power converter 5 .

[0045] Figure 2 An example of a hydrogen production system 1 ' comprising N hydrogen production systems 1 is shown, where N is an integer equal to or greater than 2. The input side 5a of each of the N single-stage power converters 5 is connected to the corresponding renewable power source 3-1 to 3-N. The output side 5b of each of the N single-stage power converters 5 is connected to a common DC bus 9, to which N electrolyzers 7-1 to 7-N are connected. The DC bus 9 can be a low voltage or medium voltage DC bus. With this design, better flexibility can be provided to match the power and rated voltage of the electrolyzers 7-1 to 7-N. In addition, higher robustness is obtained in the event of a failure or maintenance.

[0046] Figure 3 It is shown that when the first renewable power source 3-1 is an AC power source, Figure 1 to Figure 2 A first example of a general single-stage power converter 5 is depicted in FIG. The depicted single-stage power converter 5 - 1 is a rectifier.

[0047] according to Figure 3In the example in FIG. 5 , the single-stage power converter 5-1 includes a half-bridge for each electrical phase. The illustrated single-stage power converter 5-1 includes three half-bridges. Each half-bridge includes two switches S1 and S2 connected to each other, and a capacitor C on the output side 5b, which is connected across the switches S1 and S2.

[0048] According to this example, the first electrolytic cell 7-1 is connected to a DC link formed by a capacitor C on the output side 5b. The single-stage power converter 5-1 has a positive voltage terminal 5c and a negative voltage terminal 5d, and a capacitor C connected to the positive voltage terminal 5c and the negative voltage terminal 5d. The first electrolytic cell 7-1 is connected to the positive voltage terminal 5c and the negative voltage terminal 5d.

[0049] Figure 4 It is shown that when the first renewable power source 3-1 is an AC power source, Figure 1 to Figure 2 Another example of a general single-stage power converter 5 in FIG. Figure 4 The single-stage power converter 5-2 includes a three-level active neutral point clamping ANPC converter for each electrical phase. The illustrated single-stage power converter 5-2 includes three ANPC converters. Each ANPC converter includes a plurality of switches S1-S5, and two series-connected capacitors C1 and capacitor C2 at the output side 5b. The ANPC converter has a positive voltage terminal 5c, a negative voltage terminal 5d, and a neutral terminal 5e formed by a connection point between the two capacitors C1 and C2. Figure 4 The ANPC converter generates two DC voltages at its output side, namely, a voltage whose absolute value is V / 2 between the positive voltage terminal 5c and the neutral terminal 5e, and a voltage whose absolute value is V / 2 between the neutral terminal 5e and the negative voltage terminal 5d.

[0050] According to this example, the first electrolytic cell 7 - 1 is connected to the positive voltage terminal 5 c and the negative voltage terminal 5 d .

[0051] Figure 5 A single-stage power converter 5-3 is shown, which is Figure 4 In particular, the single-stage power converter 5-3 is the same as the single-stage power converter 5-2. However, according to Figure 5 In the example of , the hydrogen production system includes a second electrolyzer 7-2. The first electrolyzer 7-1 is connected to a positive voltage terminal 5d and a neutral terminal 5e. The second electrolyzer 7-2 is connected to a neutral terminal 5e and a negative voltage terminal 5d.

[0052] Figure 6 It is shown that when the first renewable power source 3-1 is a DC power source, Figure 1 to Figure 2 Another example of a general single-stage power converter 5 in FIG. Figure 6The single-stage power converter 5-4 has an interleaved buck converter topology. The single-stage power converter 5-4 has a capacitor C3 across its two input terminals on the input side. The single-stage power converter 5-4 may include, for example, three buck converters connected in parallel to form an interleaved buck converter topology, each buck converter connected in parallel being connected to two input terminals. In addition, the single-stage power converter 5-4 includes an inductor L, each inductor L being connected to a corresponding one of the buck converters, and being connected to a DC link 9 on the output side of the single-stage power converter 5-4. The first electrolyzer 7-1 is connected to the DC link 9.

[0053] Figure 7 It is shown that when the first renewable power source 3-1 is an AC power source, Figure 1 to Figure 2 Another example of a general single-stage power converter 5 in FIG. The single-stage power converter 5-5 includes a multi-port hybrid NPC converter, i.e., a multi-port hybrid neutral point clamped converter. The illustrated single-stage power converter 5-5 includes three multi-port hybrid NPC converters, which are connected to corresponding electrical phases. In particular, the single-stage power converter 5-5 includes an AC input terminal 11, which is configured to be connected to corresponding phases of an AC power source.

[0054] Each multi-port hybrid NPC converter has a first grid-side terminal 13a and a second grid-side terminal 13b connected to the power grid 15. Therefore, the single-stage power converter 5-5 outputs a total of six electrical phases. The transformer system can be configured to convert the six electrical phases into three electrical phases before connecting to the power grid 15.

[0055] exist Figure 7 In the example of FIG. 1 , each multi-port hybrid neutral point clamped converter includes a T-type converter 17 having three branches 19a-19c. The first branch 19a of the three branches is a middle branch connected to the first renewable power source 3-1. The second branch 19b is an upper branch relative to the first branch 19a. The second branch 19b forms a first grid-side terminal 13a connected to the power grid 15. Figure 7 In the circuit diagram shown, the first branch 19a and the third branch 19c are the lower branches. The third branch 19c forms the second grid-side terminal 13b.

[0056] Each multi-port hybrid NPC converter comprises two half-bridges connected to a T-converter 17. A first of these half-bridges is formed by the upper two switches which do not form part of the T-converter 17, and a second of these half-bridges is formed by the lower two switches which do not form part of the T-converter 17.

[0057] One or more electrolytic cells 7-1 may be connected to Figures 4 to 5is connected to the output side of the single-stage power converter 5 - 5 in the same manner as described in .

[0058] The single-stage power converter 5 - 5 is capable of directing power from the first renewable power source 3 - 1 to one or more electrolysers 7 - 1 and to the power grid 15 .

[0059] Figure 8 It is shown that when the first renewable power source 3-1 is a DC power source, Figure 1 to Figure 2 Another example of a general single-stage power converter 5 in FIG.

[0060] Figure 8 The single-stage power converter 5-6 is a nine-switch split source inverter. The single-stage power converter 5-6 has a first branch 19a and a second branch 19b connected to the first renewable power source 3-1. The single-stage power converter 5-6 has a branch 18 connected to the power grid 15. The first electrolyzer 7-1 is connected across the capacitor C on the output side of the single-stage power converter 5-6.

[0061] Fig. 9 Shows Figure 1 to Figure 2 Another example of a general single-stage power converter 5 in FIG.

[0062] In addition to the first renewable power source 3-1, the second renewable power source 3-2 may be connected to the single-stage power converter 5-7. The first renewable power source 3-1 and the second renewable power source 3-2 are configured to generate direct current. Therefore, the first renewable power source 3-1 and the second renewable power source 3-2 are DC power sources.

[0063] The single-stage power converter 5-7 comprises three multi-port hybrid NPC converters, each of which is connected to a corresponding electrical phase of the power grid 15. The topology is similar to Figure 7 However, the first branch 19a connected to the first renewable power source 3-1 is an upper branch, the second branch 19b forming the first grid-side terminal 13a is a middle branch and is connected to the power grid 15, and the third branch 19c of the three branches of the T-type converter is a lower branch connected to the second renewable power source 3-2.

[0064] The single-stage power converter 5-7 includes a first diode 21a and a second diode 21b. The first branch 19a is provided with the first diode 21a. The second branch 19b is provided with the second diode 21b.

[0065] The cathode side of the first diode 21a is connected to the first renewable power source 3-1. The anode side of the second diode 21b is connected to the second renewable power source 3-2.

[0066] The single-stage power converter 5-7 has a positive voltage terminal 5c and a negative voltage terminal 5d at its output side. The single-stage power converter 5-7 also has a neutral terminal 5e. In addition, the single-stage power converter 5-7 includes two capacitors C1 and C2. The first capacitor C1 of the two capacitors C1 and C2 is connected between the positive voltage terminal 5c and the neutral terminal 5e, and the second capacitor C2 of the two capacitors C1 and C2 is connected between the negative voltage terminal 5d and the neutral terminal 5e.

[0067] The first renewable power source 3-1 is modulated by two switches S1 and S2 across the first capacitor C1 and the inductor L1, and a first diode 21a and a diode of the two switches S1 and S2, the inductor being connected to the cathode side of the first diode 21a. The voltage across the first capacitor C1 may be controlled, or the current from the first renewable power source 3-1 may be controlled.

[0068] The second renewable power source 3-2 is modulated by two switches S3 and S4 across the second capacitor C2 and the inductor L2, and a second diode 21b and a diode of the two switches S3 and S4, the inductor being connected to the anode side of the second diode 21b. The voltage across the second capacitor C2 may be controlled, or the current from the second renewable power source 3-2 may be controlled.

[0069] The first electrolytic cell 7-1 may be connected to the positive voltage terminal 5c and the negative voltage terminal 5d. Alternatively, the two electrolytic cells 7-1 may be connected to the output side of the single-stage power converter 5-7 in the same manner as Figure 5 The same way as shown in the example.

[0070] The power flow may be controlled by controlled currents in the first and second renewable energy sources 3 - 1 , 3 - 2 and the power grid 15 , as well as controlling the DC link voltage, ie the voltage across the two capacitors C1 and C2 .

[0071] The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims.

Claims

1. A hydrogen production system (1, 1'), comprising: a first renewable power source (3-1), a first electrolytic cell (7-1), and A single-stage power converter (5; 5-1, 5-2; 5-3; 5-4; 5-5; 5-6; 5-7) having an input side (5a) and an output side (5b), The input side (5a) is connected to the first renewable power source (3-1), and the output side (5b) is connected to the first electrolyzer (7-1).

2. The hydrogen production system (1, 1') according to claim 1, wherein the single-stage power converter (5; 5-1, 5-2; 5-3; 5-4; 5-5; 5-6; 5-7) is a multi-level converter.

3. The hydrogen production system (1, 1') according to claim 2, wherein the output side (5b) comprises a positive voltage terminal (5c), a neutral terminal (5e) and a negative voltage terminal (5d).

4. The hydrogen production system (1, 1') according to claim 3, wherein the first electrolysis cell (7-1) is connected to the positive voltage terminal (5c) and the negative voltage terminal (5d).

5. The hydrogen production system (1, 1') according to claim 3, wherein the hydrogen production system comprises a second electrolyzer (7-2), wherein the first electrolyzer (7-1) is connected to the positive voltage terminal (5c) and the neutral terminal (5e), ​​and wherein the second electrolyzer (7-2) is connected to the neutral terminal (5e) and the negative voltage terminal (5d).

6. The hydrogen production system (1, 1') according to any one of claims 2 to 5, wherein the multi-level converter comprises a three-level active neutral point clamped (ANPC) converter.

7. The hydrogen production system (1, 1') according to any one of claims 2 to 5, wherein the multi-level converter comprises a multi-port hybrid NPC converter.

8. The hydrogen production system (1, 1') according to claim 7, wherein the multi-port hybrid NPC converter has a first grid-side terminal (13a) connected to an electric power grid (15).

9. A hydrogen production system (1, 1') according to claim 7 or 8, wherein the multi-port hybrid NPC converter comprises a T-type converter (17) having three branches (19a-19c), wherein a first branch (19a) of the three branches is connected to the first renewable power source (3-1), and a second branch (19b) of the three branches forms the first grid-side terminal (13a).

10. The hydrogen production system (1, 1') according to claim 9, wherein the first renewable power source (3-1) is configured to generate three-phase alternating current, wherein a third branch (19c) of the three branches forms a second grid-side terminal (13b) connected to the power grid (15).

11. The hydrogen production system (1, 1') according to claim 10, wherein the first branch (19a) is an intermediate branch relative to the second branch (19b) and the third branch (19c).

12. The hydrogen production system (1, 1') according to claim 9, comprising a second renewable power source (3-2), wherein the first renewable power source (3-1) and the second renewable power source (3-2) are configured to generate direct current, wherein the third branch (19c) of the three branches is connected to the second renewable power source (3-2), and wherein the second branch (19b) is an intermediate branch relative to the first branch (19a) and the third branch (19c).

13. The hydrogen production system (1, 1') according to claim 12, wherein the first branch (19a) and the third branch (19c) are respectively provided with one of a first diode (21a) and a second diode (21b).

14. The hydrogen production system (1, 1') according to claim 13, wherein the cathode side of the first diode (21a) is connected to the first renewable power source (3-1), and the anode side of the second diode (21b) is connected to the second renewable power source (3-2).

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