Power supply system to multiple electrolyzers, related equipment, and method

Abstract

To provide a power supply system to multiple electrolyzers, related equipment, and a method.SOLUTION: A power system (5) for multiple electrolyzers (2, 3, 4) comprises: a main input terminal (6) connected to a grid (G); an AC / AC power converter (7); a control circuit (10); and multiple supply branches (12, 13, 14). Each supply branch (12, 13, or 14) includes: a branch transformer (21, 22, or 23) including a primary circuit connected to an input terminal (15, 16, or 17) of the supply branch and at least one secondary circuit; and at least one rectifier (24, 25, or 26) connected to the secondary circuit of the branch transformer. The rectifier includes an output terminal (30, 31, or 32) connected to an output terminal (18, 19, or 20) of the supply branch to supply a direct current to the output terminal of the supply branch.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to electrolyzers, and more particularly to a power supply system for multiple electrolyzers, an installation including such a power supply system, and a method for supplying multiple electrolyzers. [Background technology]

[0002] Generally, an electrolysis plant contains multiple electrolyzers.

[0003] Each electrolyzer includes a water input, a dioxygen output, a dihydrogen output, and a direct current (DC) power input.

[0004] Each electrolyzer supplied by a DC power supply splits water into dihydrogen and dioxygen.

[0005] To reduce costs and plant complexity, an electrolysis plant typically includes a common water supply circuit connecting the water inputs of the multiple electrolyzers to, for example, a water tank, a common dioxygen exhaust circuit recovering the dioxygen generated by the multiple electrolyzers, and a common dihydrogen exhaust circuit recovering the dihydrogen generated by the multiple electrolyzers.

[0006] However, due to electrical insulation problems and aging of the electrolyzer cells, each electrolyzer in a multi-electrolyzer system must be supplied with electrolyte from a separate supply system.

[0007] Aging of the electrolyzer cells leads to an increase in the supply voltage of the electrolyzer.

[0008] Because electrolysers age non-uniformly, the supply voltage may vary from one electrolyser to another.

[0009] Each supply system typically includes a transformer with a primary side and a secondary side connected to a supply grid, and an alternating current AC / direct current DC power converter (AC / DC power converter).

[0010] Each AC / DC power converter uses gate turn off thyristors to increase the efficiency of the AC / DC power converter.

[0011] To reduce harmonics generated by the switching of gate turn-off thyristors that are rejected on the supply grid, the secondary side of the transformer consists of multiple secondary circuits connected to AC / DC power converters, complicating the design and manufacture of the transformer.

[0012] Additionally, each supply system includes a control circuit that controls the AC / DC power converter.

[0013] Since the number of supply systems is equal to the number of electrolysers, multiple AC / DC power converters and multiple control circuits are required, which increases the cost of the electrolysis plant and the complexity of the electrolysis plant.

[0014] It is therefore proposed to overcome in whole or in part the drawbacks associated with systems for supplying electrolyte to multiple electrolysers known from the prior art. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] US Patent Application Publication No. 2018 / 198377 Summary of the Invention

[0016] In view of the above, the present invention proposes a power supply system for multiple electrolyzers.

[0017] The power system is - main input terminals intended to be connected to a grid; - an AC / AC power converter comprising input terminals connected to the main input terminals and output terminals; - a control circuit configured to control the AC / AC power converter so that the amplitude of at least one supply current delivered in the output terminals by the AC / AC power converter from power supplied by the grid is equal to a predetermined value; - a plurality of supply branches, each supply branch comprising input terminals and at least one set of output terminals intended to be connected to an electrolyzer; - the input terminals of the plurality of supply branches being connected in series to the output terminals of the AC / AC power converter to be supplied with the supply current; - each supply branch comprising a branch transformer including a primary circuit connected to the input terminals of the said supply branch and at least one secondary circuit, and at least one rectifier connected to the secondary circuit of the branch transformer, the rectifier comprising output terminals connected to the set of output terminals of the said supply branch to supply the output terminals of the said supply branch with a DC current.

[0018] Advantageously, the number of supply branches is equal to the number of electrolysers, the set of output terminals of each supply branch being intended to be connected to an electrolyser.

[0019] Preferably, the branch transformer of at least one supply branch includes a number of secondary circuits equal to the number of phases of the primary circuit of the branch transformer, the at least one supply branch includes a number of rectifiers equal to the number of secondary circuits and includes a number of sets of output terminals equal to the number of rectifiers, each rectifier being connected to a secondary circuit of the branch transformer and including an output terminal connected to the set of output terminals of the supply branch and supplying a direct current to the set of output terminals of the supply branch, and the number of phases of the primary circuit of the branch transformer is at least equal to two.

[0020] Advantageously, the power supply system further comprises a main transformer including a primary circuit connected to the AC mains input terminals and a secondary circuit connected to the input terminals of the AC / AC power converter.

[0021] Preferably, the control circuit is further configured to control the AC / AC power converter such that the frequency of the supplied current is higher than the frequency of a grid current supplied from the utility grid on the AC mains input terminals.

[0022] Advantageously, each rectifier includes a plurality of phase legs, each phase leg including a series diode.

[0023] Preferably, each rectifier includes a plurality of phase legs, each phase leg including a transistor and a diode in series.

[0024] Advantageously, each rectifier includes a number of phase legs, each phase leg including a gate turn-off thyristor and a diode connected in series.

[0025] Preferably, at least one supply branch includes a main switch connecting the input terminals of the supply branch and shunting said supply branch such that no supply current is supplied to the primary circuit of the branch transformer of the supply branch when the main switch is closed.

[0026] Preferably, at least one supply branch includes a main switch connecting phases of at least one secondary circuit of the branch transformer of the said supply branch, such that no current is supplied to the rectifier of said supply branch when the main switch is closed.

[0027] Advantageously, at least one supply branch comprises a first switch connecting an output terminal of at least one rectifier with a set of output terminals of said supply branch, and a second switch connecting the output terminals of the rectifier, the second switch being arranged between the rectifier and the first switch.

[0028] Another object of the invention relates to an installation comprising a plurality of electrolysers and a power supply system as defined above, each electrolyser being connected to a series of output terminals of a supply branch.

[0029] Another object of the present invention relates to a method for supplying electrolyte to multiple electrolyzers.

[0030] The method is: - controlling an AC / AC power converter comprising input terminals connected to main input terminals coupled to a grid, and output terminals so that the amplitude of at least one supply current delivered in the output terminals by the AC / AC power converter from power supplied by the grid is equal to a predetermined value; - supplying input terminals of a plurality of supply branches connected in series to the output terminals of the AC / AC power converter with the supply current, each supply branch comprising at least one set of output terminals connected to an electrolyzer, a branch transformer including a primary circuit connected to the input terminals of the said supply branch and at least one secondary circuit, and at least one rectifier connected to the secondary circuit of the branch transformer, the rectifier comprising output terminals connected to the set of output terminals of the said supply branch, the rectifier supplying the set of output terminals of the said supply branch with a DC current to supply the said electrolyzer.

[0031] Advantageously, at least one supply branch comprises a main switch connecting the input terminals of the said supply branch, the main switch being open, the method comprising closing the main switch to shunt the said supply branch so that the primary circuit of the branch transformer of the said supply branch is not supplied with the supply current.

[0032] Preferably, at least one supply branch comprises a first switch connecting the output terminals of the rectifier and the set of output terminals of the said supply branch, and a second switch connecting the output terminals of the rectifier, the second switch being located between the rectifier and the first switch, the first switch being closed to supply the electrolyzer and the second switch be open, and the method further comprises: - closing a second switch; - opening the first switch when the second switch is closed. [Brief description of the drawings]

[0033] Other characteristics and advantages of the invention will become apparent from the following description of embodiments of the invention, given by way of non-limiting example only, with reference to the drawings, in which: [Figure 1] 1 shows a schematic diagram of an example of an installation according to the invention; [Diagram 2] 1 illustrates a schematic diagram of an example of a rectifier according to the present invention; [Diagram 3] 1 shows a schematic diagram of a first embodiment of a switch according to the invention; [Figure 4]2 shows diagrammatically a second embodiment of a switch according to the invention; [Diagram 5] 3 shows diagrammatically a third embodiment of a switch according to the invention; [Figure 6] 4 shows diagrammatically another third embodiment of a supply branch according to the invention; [Figure 7] 3 shows another example of a rectifier according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] FIG. 1 shows an example of an installation 1 including multiple electrolyzers 2 , 3 , 4 and a power supply 5 .

[0035] Facility 1 includes N electrolyzers, where N is a non-zero integer (N being a none nil integer).

[0036] Equipment 1 includes three electrolyzers 2, 3, and 4.

[0037] The power supply system 5 includes a main input terminal 6 connected to a grid (system) G via a breaker B.

[0038] The grid G ​​may be a three-phase grid supplying a three-phase current IG.

[0039] In a variant, the grid may be an M-phase grid supplying M phase currents I G , where M being a none nil integer.

[0040] The grid G ​​is supplied, for example, by a solar farm including at least one solar panel and / or a wind farm including at least one wind turbine.

[0041] Each electrolyser 2, 3, 4 comprises a first input 2a, 3a, 4a connected to a pump P supplying water from a tank T, for example.

[0042] The water may be a mixture of potassium hydroxide or sodium hydroxide.

[0043] Each electrolyser 2, 3, 4 further comprises a first output 2b, 3b, 4b and a second output 2c, 3c, 4c.

[0044] Each electrolyser 2 , 3 , 4 includes a terminal 2 d , 3 d , 4 d that is connected to a power supply 5 .

[0045] When water is supplied to the electrolyzers 2, 3, and 4 from the pump P and a direct current is supplied from the power supply unit 5, the electrolyzers 2, 3, and 4 decompose the water into dihydrogen and dioxygen.

[0046] Dioxygen generated by the electrolyzers 2, 3, 4 may exhaust the electrolyzer 2, 3, 4 through the first output 2b, 3b, 4b and dihydrogen generated by the electrolyzer 2, 3, 4 may exhaust the electrolyzer 2, 3, 4 through the second output 2c, 3c, 4c.

[0047] The power supply system 5 includes an alternating current AC / AC power converter 7 including an input terminal 8 and an output terminal 9 , and a control circuit 10 .

[0048] The output terminals 9 of the AC / AC power converter 7 are X-phase output terminals, X being a none nil integer so that the output terminals 9 deliver a X-phase supply current Is.

[0049] Assume that X is equal to 3, such that the AC / AC power converter 7 delivers at its output terminals 9 a three-phase supply current Is.

[0050] In another variant, X is equal to 1, so that output terminal 9 provides a single-phase supply current.

[0051] The power supply system 5 further comprises a main transformer 11 including a primary circuit connected to the AC mains input terminals 6 and a secondary circuit connected to the input terminals 8 of the AC / AC power converter 7 .

[0052] The main transformer 11 can adapt the voltage supplied to the power converter 7 from the grid G, e.g. to optimize the design of the power converter 7, e.g. to reduce the cost of the power converter 7, and can filter perturbations on the grid G, for example overvoltage.

[0053] In an alternative embodiment, the power supply system 5 does not include a mains transformer 11 and the input terminals 8 of the AC / AC power converter 7 are connected directly to the AC mains input terminals 6 .

[0054] The power supply system 5 further comprises N supply branches 12 , 13 , 14 such that the number of supply branches is equal to the number of electrolysers 2 , 3 , 4 .

[0055] Each supply branch 12,13,14 includes an input terminal 15,16,17 and an output terminal 18,19,20.

[0056] The input terminals 15 , 16 , 17 of the supply branches 12 , 13 , 14 are connected in series to the output terminals 9 of the AC / AC power converter 7 .

[0057] A set of output terminals 18 of a first supply branch 12 is connected to terminals 2d of the first electrolyzer 2, a set of output terminals 19 of the second supply branch 13 is connected to terminals 3d of the second electrolyzer 3, and a set of output terminals 20 of the third supply branch 14 is connected to terminals 4d of the third electrolyzer 4.

[0058] Each supply branch 12, 13, 14 comprises a primary circuit including the X phase, a branch transformer 21, 22, 23 connected to an input terminal 15, 16, 17 of the supply branch 12, 13, 14, and a secondary circuit including the X phase.

[0059] The branch transformers 21, 22, 23 may have the same transformation ratio or at least one branch transformer may have a transformation ratio different from that of the other branch transformers.

[0060] Each supply branch 12, 13, 14 further comprises a rectifier 24, 25, 26 which comprises an X phase and comprises input terminals 27, 28, 29 connected to the secondary circuit of the branch transformer 21, 22, 23 of that supply branch, and output terminals 30, 31, 32 for supplying a direct current.

[0061] Each supply branch 12, 13, 14 further comprises a main switch 33, 34, 35 connecting the input terminals 15, 16, 17 of that supply branch.

[0062] In a variant, the main switches 33, 34, 35 of a supply branch 12, 13, 14 connect the X phase of the secondary circuits of the branch transformers 21, 22, 23 of said supply branch 12, 13, 14.

[0063] In another variant, at least one supply branch 12 , 13 , 14 includes a main switch 33 , 34 , 35 .

[0064] In another variant, the supply branches 12, 13, 14 do not include a main switch.

[0065] Each supply branch 12, 13, 14 further includes a first switch 36, 37, 38 connecting the output terminals 30, 31, 32 of the rectifiers 24, 25, 26 with the set of output terminals 18, 19, 20 of said supply branch, and a second switch 39, 40, 41 connecting the output terminals 30, 31, 32 of the rectifiers 24, 25, 26 of said supply branch, the second switch 39, 40, 41 being arranged between the rectifiers 24, 25, 26 of said supply branch and the first switch 36, 37, 38 of said branch.

[0066] In a variant, at least one supply branch 12,13,14 comprises a first and a second switch 36,37,38,39,40,41 or none of the supply branches 12,13,14 comprises a first and a second switch 36,37,38,39,40,41.

[0067] If a supply branch 12, 13, 14 does not include the first and second switches 36, 37, 38, 39, 40, 41, the output terminals 30, 31, 32 of the rectifiers 24, 25, 26 of that supply branch are directly connected to the set of output terminals 18, 19, 20 of that supply branch.

[0068] FIG. 2 shows a schematic diagram of one example of the rectifiers 24, 25, and .

[0069] Rectifiers 24, 25, and 26 include X phase legs 50, 51, and 52.

[0070] Since X is assumed to be equal to three, rectifiers 24, 25, 26 include three phase legs 50, 51, 52.

[0071] Each of the phase legs 50, 51, and 52 includes a first terminal 50a, 51a, and 52a, a second terminal 50b, 51b, and 51b, and a third terminal 50c, 51c, and 52c.

[0072] A first terminal 50a, 51a, 52a of each phase leg 50, 51, 52 is connected to a first connection C1 of the output terminals 18, 19, 20, and a second terminal 50b, 51b, 52b of each phase leg 50, 51, 52 is connected to a second connection C2 of the output terminals 18, 19, 20.

[0073] The third terminal 50c of the first phase leg 50 is connected to the first phase P1 of the input terminals 27, 28, 29.

[0074] The third terminal 51c of the second phase leg 51 is connected to the input terminals 27, 28, 29 of the second phase P2.

[0075] The third terminal 52c of the third phase leg 52 is connected to the third phase P3 of the input terminals 27, 28, 29.

[0076] Each phase leg 50 , 51 , 52 includes a first switch 53 and a second switch 54 .

[0077] The first switch 53 includes a first terminal 53a connected to the first terminals 50a, 51a, 52a of the phase legs 50, 51, 52 and a second terminal 53b connected to the third terminals 50c, 51c, 52c of the phase legs 50, 51, 52.

[0078] The second switch 54 includes a first terminal 54a connected to the third terminals 50c, 51c, 52c of the phase legs 50, 51, 52 and a second terminal 54b connected to the second terminals 50b, 51b, 52b of the phase legs 50, 51, 52.

[0079] FIG. 3 shows diagrammatically a first embodiment of the first and second switches 53, 54.

[0080] Each of the first and second switches 53, 54 includes a diode 55 extending between first and second terminals 53a, 54a, 53b, 54b, with the cathode of the diode 55 connected to the first terminal 53a, 54a of the switch and the anode of the diode 55 connected to the second terminal 53b, 54b of the switch.

[0081] The first embodiment of the first and second switches 53, 54 including the diode 55 simplifies the implementation of the rectifiers 24, 25, 26 since the diode 55 needs to be controlled by the control circuit.

[0082] Each switch 53, 54 may include multiple diodes 55 connected in series such that the anode of one diode is connected to the cathode of the other diode.

[0083] FIG. 4 shows diagrammatically a second embodiment of the first and second switches 53, 54.

[0084] Each of the first and second switches 53, 54 includes a diode 55 extending between first and second terminals 53a, 54a, 53b, 54b, with the cathode of the diode 55 connected to the first terminal 53a, 54a of the switch and the anode of the diode 55 connected to the second terminal 53b, 54b of the switch.

[0085] Each switch further includes a gate turn-off thyristor 56 .

[0086] The gate of the gate turn-off thyristor 56 is connected to, for example, the control circuit 10 or other control circuit.

[0087] The anode of the gate turn-off thyristor 56 is connected to the cathode of the diode 55 , and the cathode of the gate turn-off thyristor 56 is connected to the anode of the diode 55 .

[0088] Each switch 53, 54 may consist of multiple gate turn-off thyristors 56 connected in series such that the anode of one thyristor is connected to the cathode of the other thyristor.

[0089] FIG. 5 shows diagrammatically a third embodiment of the first and second switches 53, 54.

[0090] Each of the first and second switches 53, 54 is configured with a diode 55 extending between first and second terminals 53a, 54a, 53b, 54b, with the cathode of the diode 55 connected to the first terminal 53a, 54a of the switch and the anode of the diode 55 connected to the second terminal 53b, 54b of the switch.

[0091] Each switch further includes a field effect transistor 58 .

[0092] Field-effect transistor 58 may be, for example, an insulated gate bipolar transistor using a silicon-based semiconductor such as an insulated gate bipolar transistor IGBT or an injection-enhanced gate transistor IEGT, or using silicon carbide semiconductors such as metal-oxide-semiconductor field-effect transistor MOSFET.

[0093] The gate of transistor 58 is connected to control circuit 10 or another control circuit.

[0094] The drain of transistor 58 is connected to the cathode of diode 55 , and the source of transistor 58 is connected to the anode of diode 55 .

[0095] Each switch 53, 54 may include multiple transistors 58 and diodes 55 connected in series and parallel such that the drain of one transistor is connected to the source of the other transistor.

[0096] In the following, an embodiment of the power supply device 5 is disclosed.

[0097] It is assumed that the breaker B is closed so that the grid G ​​supplies the main input terminals 6 and the main switches 33, 34, 35 are open. The primary circuit of the branch transformers 21, 22, 23 are supplied by the AC / AC power converter 7.

[0098] Furthermore, it is assumed that the first switches 36, 37, 38 are closed and the second switches 39, 40, 41 are open.

[0099] The control circuit 10 controls the AC / AC power converter 7 so that the output terminal 9 of the AC / AC power converter 7 supplies a three-phase supply current Is from the power supplied from the grid G, and the amplitude of the three-phase supply current Is is equal to a predetermined value.

[0100] The AC / AC power converter 7 supplies a supply current Is to input terminals 14, 15, 16 of supply branches 12, 13, 14 connected in series to the output terminal 9 of the AC / AC power converter.

[0101] For each supply branch 12, 13, 14, the secondary circuit of a branch transformer 21, 22, 23 supplies an alternating current from the supply Is to the input terminals 27, 28, 29 of a rectifier 24, 25, 26 of the supply branch in question.

[0102] The rectifiers 24, 25, 26 of the supply branch provide at their output terminals 30, 31, 32 a direct current which supplies the electrolysers 2, 3, 4 which are connected to the output terminals 18, 19, 20 of the supply branch.

[0103] The branch transformers 21, 22, 23 provide galvanic isolation between the rectifiers 25, 25, 26 and the AC / AC power converter 7, so that the supply system 5 implements only one AC / AC power converter 7 to supply the multiple electrolyzers 2, 3, 4, as opposed to conventionally known electrolysis plants in which each electrolyzer is supplied by a dedicated power converter.

[0104] The control circuit 10 further controls the AC / AC power converter 7 so that the frequency of the supply current Is is higher than the frequency of the grid current IG supplied from the grid G, thereby making it possible to reduce the sizes of the branch transformers 21, 22, and 23.

[0105] For example, the frequency of the grid current IG is equal to 50 Hz, and the control circuit 10 controls the AC / AC power converter 7 such that the frequency of the supply current Is is equal to 100 Hz. Since the frequency of the supply current Is is twice the frequency of the grid current IG, the volume of the branch transformer can be, for example, approximately halved, which can reduce the cost and size of the branch transformer.

[0106] The control circuit 10 may close the main switches 33, 34, 35 of the supply branches 12, 13, 14 to shunt the supply branches in question so that no supply current is supplied to the primary circuits of the branch transformers 21, 22, 23 of the supply branches in question or so that no current is supplied to the rectifiers 24, 25, 26 of the supply branches in question.

[0107] A supply branch 12, 13, 14 may be shunted in case of a detected fault in that branch, e.g. a fault in the branch transformer, rectifier, electrolyser or insulation of the supply branch, or when maintenance work is carried out, so that the supply current Is is fed to the other supply branch, thereby keeping the electrolyser of the other supply branch powered and avoiding propagation of the fault.

[0108] The rectifiers 24, 25, 26 of the supply branch do not supply current, for example when a fault in a rectifier or electrolyzer or insulation failure in a supply branch is detected, or when maintenance work is performed, and the supply current Is is supplied to the other supply branches, thereby supplying power to the electrolyzers of the other supply branches, thereby avoiding the propagation of the fault.

[0109] When an electrolyser 2, 3, 4 needs to be replaced, for example, or when maintenance work needs to be performed on that electrolyser, the control circuit 10 closes the second switches 39, 40, 41 and, when the second switches 39, 40, 41 are closed, opens the first switches 36, 37, 38 to isolate that electrolyser from the power supply system 5 while the other electrolyzers are supplied with power from the power supply system 5.

[0110] FIG. 6 shows diagrammatically another example of the supply branches 12, 13, 14 when the number of phases X is at least equal to two.

[0111] The supply branch sections 12, 13, 14 each include a branch transformer 60 including a primary circuit having X phases connected to input terminals 15, 16, 17 of the supply branch sections 12, 13, 14, and a number of secondary circuits equal to the number of phases X of the primary circuits, each secondary circuit being connected across a winding of the secondary circuit.

[0112] The supply branches 12, 13, 14 further include as many rectifiers as there are secondary circuits and include as many sets of output terminals as there are rectifiers.

[0113] Since the number of phases of the primary circuits is equal to three, the branch transformer 60 includes a first secondary circuit 61, a secondary circuit 62 and a third secondary circuit 63.

[0114] The branch transformer 60 includes three secondary circuits 61,62,63 and the supply branches 12,13,14 include three rectifiers 64,65,66 with input terminals 67,68,69 and output terminals 70,71,72.

[0115] Each of the input terminals 67, 68, 69 and output terminals 70, 71, 72 of the rectifiers 64, 65, 66 includes two phases.

[0116] The branch transformer 60 includes three rectifiers 64 , 65 , 66 and the supply branches 12 , 13 , 14 include three sets of output terminals 73 , 74 , 75 .

[0117] The input terminals 67 of the first rectifier 64 are connected to the first secondary circuit 61 and the output terminals 70 of the first rectifier 64 are connected to a first set of output terminals 73 .

[0118] The input terminals 68 of the second rectifier 65 are connected to the second secondary circuit 62 and the output terminals 71 of the second rectifier 65 are connected to a second set of output terminals 74 .

[0119] The input terminals 69 of the third rectifier 66 are connected to the third secondary circuit 63 and the output terminals 72 of the third rectifier 66 are connected to the third output terminals 75 .

[0120] The first set of output terminals 73 are connected to terminals 2d of the first electrolyzer 2, the second set of output terminals 74 are connected to terminals 3d of the second electrolyzer 3, and the third set of output terminals 75 are connected to terminals 4d of the third electrolyzer 4.

[0121] Each rectifier 64, 65, 66 supplies a supply current Is to an electrolyzer 2, 3, 4 connected to the output terminal of the rectifier.

[0122] The supply branches 12, 13, 14 may supply more than one electrolyzer, for example three electrolyzers 2, 3, 4 as depicted in Figure 6 when X is equal to 3. The supply branches 12, 13, 14 may include main switches 33, 34, 35 as described above.

[0123] The supply branches 12, 13, 14 may further include first and second switches 36, 37, 38, 39, 40, 41 as described above.

[0124] FIG. 7 shows examples of rectifiers 64, 65, and 66.

[0125] The rectifiers 64,65,66 include two phase legs 80,81.

[0126] Each phase leg 80, 81 includes a first terminal 80a, 81a, a second terminal 80b, 81b and a third terminal 80c, 81c.

[0127] A first terminal 80a, 81a of each phase leg 80, 81 is connected to a first connection C11 of the output terminals 70, 71, 72, and a second terminal 80b, 81b of each phase leg 80, 81 is connected to a second connection C21 of the output terminals 70, 71, 72.

[0128] The third terminal 80c of the first phase leg 80 is connected to the first phase P11 of the input terminals 67, 68, 69.

[0129] The third terminal 81c of the second phase leg 81 is connected to the input terminals 67, 68, 69 of the second phase P12.

[0130] Each phase leg 80, 81 includes a first switch 53 and a second switch 54.

[0131] A first terminal 53a of the first switch 53 is connected to first terminals 80a, 81a of the phase legs 80, 81, and a second terminal 53b of the first switch 53 is connected to third terminals 80c, 81c of the phase legs 80, 81.

[0132] The first terminal 55a of the second switch 54 is connected to the third terminals 80c, 81c of the phase legs 80,81, and the second terminal 54b of the second switch 54 is connected to the second terminals 80b, 81b of the phase legs 80,81. [Explanation of symbols]

[0133] 1: Equipment 2, 3, 4: Electrolyser 2b, 3b, 4b: 1st output 2c, 3c, 4c: 2nd output 2d, 3d, 4d: Terminal 5: Power supply 6: Main input terminal 7: AC / AC power converter 8: Input terminal 9: Output terminal 10: Control circuit 11: Main transformer 12, 13, 14: Supply branch 15, 16, 17: Input terminal 18, 19, 20, 73, 74, 75: Output terminal 21, 22, 23, 60: Branch transformer 24, 25, 26, 64, 65, 66: Rectifier 30, 31, 32, 70, 71, 72: Output terminal 33, 34, 35: Main switch 36, 37, 38, 53: 1st switch 39, 40, 41, 54: 2nd switch 50, 51, 52, 80, 81: Legs 50a, 51a, 52a: First terminals 50b, 51b, 51b: Second terminals 50c, 51c, 52c: Third terminals 53a, 54a, 80a, 81a: First terminals 53b, 54b, 80b, 81b: Second terminals 55: Diode 56: Gate turn-off thyristor 58: Field effect transistor 61, 62, 63: Secondary circuit 73, 74, 75: Output terminals 80a, 81a: First terminals 80b, 81b: Second terminals 80c, 81c: Third terminals B: Circuit breaker / interrupter C1, C11: First connection C2, C21: Second connection G: Grid IG: M-phase current / Three-phase current / Grid current Is: Supply current P: Pump P1, P11: 1st phase P2, P12: 2nd phase P3: 3rd phase T: Tank

Claims

1. A power supply system (5) for a plurality of electrolyzers (2, 3, 4), comprising: a main input terminal (6) intended to be connected to the grid (G); an AC / AC power converter (7) including an input terminal (8) connected to the main input terminal (6) and an output terminal (9); a control circuit (10) configured to control the AC / AC power converter (7) such that an amplitude of at least one supply current (Is) supplied by the AC / AC power converter to an output terminal (9) from power supplied from the grid is equal to a predetermined value; a plurality of supply branches (12, 13, 14); Each supply branch (12, 13, 14) comprises an input terminal (15, 16, 17) and at least one set of output terminals (18, 19, 20, 73, 74, 75) intended to be connected to an electrolyser (2, 3, 4); The input terminals (15, 16, 17) of the plurality of supply branches (12, 13, 14) are connected in series with the output terminals of an AC / AC power converter to which the supply current is supplied; Each supply branch (12, 13, 14) comprises a branch transformer (21, 22, 23, 60) including a primary circuit connected to the input terminals (15, 16, 17) of the supply branch and at least one secondary circuit, at least one rectifier (24, 25, 26, 64, 65, 66) connected to the secondary circuit of the branch transformer, The rectifier includes output terminals (30, 31, 32, 70, 71, 72) connected to the output terminals (18, 19, 20, 73, 74, 75) of the supply branches and supplies direct current to the output terminals of the supply branches.

2. 2. The power supply system according to claim 1, wherein the number of supply branches (12, 13, 14) is equal to the number of electrolyzers (2, 3, 4), and wherein the set of output terminals (18, 19, 20) of each supply branch (12, 13, 14) is intended to be connected to one of the electrolyzers (2, 3, 4).

3. 2. The power supply system according to claim 1, wherein the branch transformer (60) of at least one supply branch (12, 13, 14) comprises a number of secondary circuits (61, 62, 63) equal to the number of phases of the primary circuit of the branch transformer (60), the at least one supply branch (12, 13, 14) comprises a number of rectifiers (64, 65, 66) equal to the number of secondary circuits, and a number of sets of output terminals (73, 74, 75) equal to the number of rectifiers, each rectifier comprising an output terminal (70, 71, 72) connected to a secondary circuit of the branch transformer and connected to a set of output terminals (73, 74, 75) of the supply branch, and supplying a direct current to the set of output terminals of the supply branch, and wherein the number of phases of the output terminals (9) of the AC / AC power converter (7) is at least equal to two.

4. 2. The power supply system of claim 1, further comprising a main transformer (11) including a primary side circuit connected to the AC mains input terminals (6) and a secondary side circuit connected to an input terminal (8) of the AC / AC power converter.

5. 2. The power supply system of claim 1, wherein the control circuit (10) is further configured to control the AC / AC power converter (7) such that a frequency of the supply current (Is) is higher than a frequency of a grid current (Ig) supplied from a grid on the AC mains input terminals (6).

6. 2. The power supply system of claim 1, wherein each rectifier (24, 25, 26, 64, 65, 66) includes a plurality of phase legs (50, 51, 52, 80, 81), each phase leg including a diode (55) in series.

7. 2. The power supply system of claim 1, wherein each rectifier (24, 25, 26, 64, 65, 66) includes a plurality of phase legs (50, 51, 52, 80, 81), each phase leg including a transistor (58) and a diode (55) in series.

8. 2. The power supply system of claim 1, wherein each rectifier (24, 25, 26, 64, 65, 66) includes a plurality of phase legs (50, 51, 52, 80, 81), each phase leg including a gate turn-off thyristor (56) and a diode (55) connected in series.

9. 2. The power supply system of claim 1, wherein at least one supply branch (12, 13, 14) includes a main switch (33, 34, 35) for shunting the supply branch by connecting input terminals (15, 16, 17) of the supply branch such that no supply current is supplied to the primary circuit of a branch transformer (21, 22, 23, 60) of the supply branch when the main switch is closed.

10. 2. The power supply system according to claim 1, wherein at least one supply branch (12, 13, 14) comprises a main switch (33, 34, 35) which connects a phase of at least one secondary circuit (61, 62, 63) of a branch transformer (21, 22, 23) of the supply branch (12, 13, 14) such that no current is supplied to a rectifier (24, 25, 26, 64, 65, 66) of the supply branch when the main switch (33, 34, 35) is closed.

11. 11. The power supply system according to claim 1, wherein at least one supply branch (12, 13, 14) comprises a second switch (39, 40, 41) connecting an output terminal (30, 31, 32, 70, 71, 72) of at least one rectifier (24, 25, 26, 64, 65, 66) to a set of output terminals (18, 19, 20, 73, 74, 75) of the supply branch (12, 13, 14), and a second switch (39, 40, 41) connecting an output terminal (30, 31, 32, 70, 71, 72) of a rectifier (24, 25, 26, 64, 65, 66), the second switch being arranged between the rectifier and the first switch.

12. 2. The power supply system of claim 1, comprising a plurality of electrolysers (2, 3, 4), each electrolyser being connected to a set of output terminals (18, 19, 20, 73, 74, 75) of a supply branch.

13. A method for supplying an electrolyte to a plurality of electrolyzers (2, 3, 4), comprising the steps of: controlling an AC / AC power converter (7) such that an amplitude of at least one supply current (Is) supplied by the AC / AC power converter to an output terminal from power supplied from a grid is equal to a predetermined value, the AC / AC power converter (7) including an input terminal (8) connected to the grid (G) and an output terminal (9); providing a supply current to input terminals (15, 16, 17) of a plurality of supply branches (12, 13, 14) connected in series with output terminals of the AC / AC power converter, Each supply branch includes at least one set of output terminals (18, 19, 20, 73, 74, 75) connected to an electrolyzer (2, 3, 4), a branch transformer (21, 22, 23, 60) including a primary circuit and at least one secondary circuit connected to the input terminals of said supply branch, and at least one rectifier connected to the secondary circuit of said branch transformer; a rectifier including an output terminal connected to the output terminal of the supply branch, the rectifier providing a direct current to the output terminal of the supply branch for supplying the electrolyzer.

14. 14. The method according to claim 13, wherein at least one supply branch (12, 13, 14) comprises a main switch (33, 34, 35) connecting input terminals (15, 16, 17) of said supply branch, said main switch being open, said method comprising the step of closing said main switch to shunt said supply branch and to prevent a supply current (Is) being supplied to a primary circuit of a branch transformer of said supply branch.

15. 15. The method according to claim 13 or 14, wherein at least one supply branch (12, 13, 14) comprises an output terminal (30, 31, 32, 70, 71, 72) of a rectifier (24, 25, 26, 64, 65, 66) and a set of output terminals (18, 19, 20, 73, 74, 5) of the supply branch and a second switch (39, 40, 41) connecting the output terminals of the rectifier, the second switch being arranged between the rectifier and the first switch, the first switch being closed to supply the electrolyzer and the second switch being open, the method comprising the steps of closing the second switch (39, 40, 41) and opening the first switch (36, 37, 38) when the second switch (36, 37, 38) is closed.

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