ENERGY SUPPLY DEVICE FOR AN ELECTROLYSIS UNIT AND ELECTROLYSIS INSTALLATION

Abstract

The disclosure describes an energy supply device for an electrolysis unit and an electrolysis installation comprising the energy supply device and an electrolysis unit connected thereto.

Claims

1. An energy supply device for an electrolysis unit, comprising: a grid connection terminal configured to connect to an energy supply grid, a DC voltage output terminal configured to connect to an electrolyzer of the electrolysis unit, an auxiliary power output terminal configured to connect to at least one auxiliary unit of the electrolysis unit, a first multi-winding transformer having a primary side, connected to the grid connection terminal, and a secondary side, a second transformer with a primary side, connected to the grid connection terminal, and a secondary side, wherein the secondary side of the first multi-winding transformer has a first secondary-side connection and a second secondary-side connection galvanically isolated therefrom, wherein the first secondary-side connection provides a first voltage amplitude .Math..sub.1 and is connected to the auxiliary power output terminal, and wherein the second secondary-side connection provides a second voltage amplitude .Math..sub.2 and is connected to an AC connection of a first AC/DC converter, a DC connection of which is connected to the DC voltage output terminal, and wherein the secondary side of the second transformer has a third secondary-side connection providing a third voltage amplitude .Math..sub.3 and is connected to an AC connection of a second AC/DC converter, a DC connection of which is connected to the DC voltage output terminal, and wherein the primary side and the first secondary-side connection of the first multi-winding transformer or the primary side and the secondary side of the first multi-winding transformer do not comprise a tap changer.

2. The energy supply device according to claim 1, wherein the secondary side of the second transformer has a fourth secondary-side connection which provides a fourth voltage amplitude .Math..sub.4 and is connected to an AC connection of a third AC/DC converter, a DC connection of which is connected to the DC voltage output terminal.

3. The energy supply device according to claim 1, wherein the second transformer comprises a tap changer on its primary side or its secondary side.

4. The energy supply device according to claim 1, wherein at least one AC/DC converter is connected on an AC side thereof to its respective transformer via an AC isolation unit having pre-charging circuitry.

5. The energy supply device according to claim 1, wherein, between each of the AC/DC converters and the DC voltage output terminal there is arranged a DC isolation unit of which one or more of the DC isolation units are free of a pre-charging circuit.

6. The energy supply device according to claim 1, wherein the second voltage amplitude .Math..sub.2 is greater than the third voltage amplitude .Math..sub.3.

7. The energy supply device according to claim 1, wherein the second transformer comprises a multi-winding transformer, and wherein the first multi-winding transformer and the second transformer have the same nominal power.

8. The energy supply device according to claim 1, wherein the second secondary-side connection has a nominal power that is different by at least 10% from that of the first secondary-side connection.

9. The energy supply device according to claim 2, wherein a nominal power of the third secondary-side connection is different from a nominal power of the fourth secondary-side connection.

10. The energy supply device according to claim 1, wherein the second secondary-side connection has a nominal power higher than half the nominal power present at the secondary side of the second transformer.

11. The energy supply device according to claim 1, wherein the energy supply device is configured for connection to a medium-voltage grid as the energy supply grid.

12. The energy supply device according to claim 1, wherein the first multi-winding transformer comprises a three-winding transformer with a primary winding and two separate secondary windings.

13. The energy supply device according to claim 1, wherein the first multi-winding transformer comprises a four-winding transformer with two primary windings and two separate secondary windings.

14. The energy supply device according to claim 2, wherein the first AC/DC converter comprises a transistor-based AC/DC converter.

15. The energy supply device according to claim 14, wherein the second AC/DC-converter and/or the third AC/DC-converter comprises a transistor based AC/DC converter.

16. An electrolysis installation, comprising: an electrolysis unit with an electrolyzer and at least one auxiliary unit for a chemical supply of the electrolyzer, and an energy supply device comprising: a grid connection terminal configured to connect to an energy supply grid, a DC voltage output terminal configured to connect to the electrolyzer of the electrolysis unit, an auxiliary power output terminal configured to connect to the at least one auxiliary unit of the electrolysis unit, a first multi-winding transformer having a primary side, connected to the grid connection terminal, and a secondary side, a second transformer with a primary side, connected to the grid connection terminal, and a secondary side, wherein the secondary side of the first multi-winding transformer has a first secondary-side connection and a second secondary-side connection galvanically isolated therefrom, wherein the first secondary-side connection provides a first voltage amplitude .Math..sub.1 and is connected to the auxiliary power output terminal, and wherein the second secondary-side connection provides a second voltage amplitude .Math..sub.2 and is connected to an AC connection of a first AC/DC converter, a DC connection of which is connected to the DC voltage output terminal, and wherein the secondary side of the second transformer has a third secondary-side connection which provides a third voltage amplitude .Math..sub.3 and is connected to an AC connection of a second AC/DC converter, a DC connection of which is connected to the DC voltage output terminal, and wherein the primary side and the first secondary-side connection of the first multi-winding transformer or the primary side and the secondary side of the first multi-winding transformer do not comprise a tap changer, wherein the DC voltage output terminal of the energy supply device is connected to the electrolyzer and the auxiliary power output terminal of the energy supply device is connected to the at least one auxiliary unit of the electrolysis unit.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0035] The disclosure is illustrated below with the aid of figures. In the figures:

[0036] FIG. 1 shows a conventional electrolysis installation in a first variant,

[0037] FIG. 2 shows a conventional electrolysis installation in a second variant, and

[0038] FIG. 3 shows an electrolysis installation according to the disclosure having an energy supply device according to the disclosure, in an embodiment.

DETAILED DESCRIPTION

[0039] FIG. 3 shows an electrolysis installation 50 according to the disclosure with an energy supply device 10 according to the disclosure. The electrolysis installation 50 comprises the energy supply device 10 according to the disclosure, an electrolysis unit 20, and a control unit 30. In the present disclosure, reference to the term unit is intended to cover any corresponding device, structure, component, circuit or circuitry, etc., and is not intended to be interpreted in a limiting fashion or as a nonce term.

[0040] The energy supply device 10 is described in detail below. The energy supply device 10 is connected to an energy supply grid 40 via a grid connection or terminal 15. An AC isolation unit 3 is arranged between the grid connection 15 and each of the transformers 2 and 4. The first transformer 2 is a multi-winding transformer and has a primary side 2P, connected to the grid connection 15, and a secondary side 2S. The secondary side 2S has a first secondary-side connection or terminal 2S1 and a second secondary-side connection or terminal 2S2. The first secondary-side connection 2S1 is connected to the electrolysis unit 20 via an auxiliary power output (or output terminal) 17 and supplies it with an alternating voltage with a first voltage amplitude .Math..sub.1. The second secondary-side connection 2S2 is connected to an AC connection 6.1 of a first AC/DC converter 6 via an AC isolation unit 5 with pre-charging means, mechanism or circuit VL, and supplies it with a second AC voltage amplitude .Math..sub.2. The first AC/DC converter 6 is connected with its DC connection 6.2 to a DC voltage output (or output terminal) 16 via an output capacitor 9 and a DC isolation unit 11. The first AC/DC converter 6 operates in a rectifying mode during operation of the electrolysis installation 50 and can convert the AC voltage at its AC connection 6.1 into a DC voltage at its DC connection 6.2, which is then also present at the DC voltage output 16 of the energy supply device 10 when the DC isolation unit 11 is closed.

[0041] By way of example, in one embodiment the second transformer 4 is configured as a multi-winding transformer and has a primary side 4P and a secondary side 4S. The secondary side 4S has a third secondary-side connection or terminal 4S3 and a fourth secondary-side connection or terminal 4S4. The third secondary-side connection 4S3 is connected via an AC isolation unit 5 with pre-charging means, mechanism or circuit VL to an AC connection 7.1 of a second AC/DC converter 7, and supplies it with an alternating voltage having a third AC voltage amplitude .Math..sub.3. Furthermore, the second AC/DC converter 7 is connected with its DC connection 7.2 to the DC voltage output 16 via an output capacitor 9 and a DC isolation unit 12, which has pre-charging means, mechanism or circuit VL. The second AC/DC converter 7 can convert the AC voltage at the AC connection 7.1 into a DC voltage at the DC connection 7.2, which is then present at the DC voltage output 16.

[0042] The fourth secondary-side connection 4S4 is connected to an AC connection 8.1 of a third AC/DC converter 8 via an AC isolation unit 5 with pre-charging means or circuitry, and supplies it with an alternating voltage having a fourth voltage amplitude .Math..sub.4. Furthermore, the third AC/DC converter 8 is connected with its DC connection 8.2 to the DC voltage output 16 via an output capacitor 9 and a DC isolation unit 12. The third AC/DC converter 8 can convert the AC voltage at the AC connection 8.1 into a DC voltage at its DC connection 8.2, which is then present at the DC voltage output 16. In other words, the AC/DC converters 6, 7, 8 can each convert an AC voltage with different voltage amplitudes .Math..sub.2, .Math..sub.3, .Math..sub.4 into a DC voltage and are connected to the DC voltage output 16 so that the DC voltage is present at the DC voltage output 16. The first AC/DC converter 6, and if applicable the further AC/DC converters 7, 8, can, in one embodiment, each be a transistor-based AC/DC converter. All AC isolation units 3, all AC isolation units 5 with pre-charging means or circuitry, all DC isolation units 11 and the DC isolation unit 12 with pre-charging means or circuitry, as well as the AC/DC converters 6, 7, 8, are controlled by the control unit 13 of the energy supply device 10if necessary, also in combination with the overall control unit 30.

[0043] In the embodiment of FIG. 3, the output capacitors 9 are each shown as separate components which are connected to the DC connections 6.2, 7.2, 8.2 of the AC/DC converters 6, 7, 8 assigned to them. Alternatively, however, it is also possible for the output capacitors 9 to be at least partially, and possibly also completely, integrated into the AC/DC converters 6, 7, 8 respectively assigned to them, and therefore to be part of the AC/DC converters 6, 7, 8 respectively assigned to them.

[0044] The electrolysis unit 20 is described in detail below. The electrolysis unit 20 has an electrolyzer 22, an auxiliary unit 23, which can be, for example, a pump, an auxiliary unit 24, which can be, for example, a heater, and a control unit 25 of the electrolysis unit 22. Only two auxiliary units are shown as examples. However, it is within the scope of the disclosure for the electrolysis unit 20 to also have a different number of auxiliary units, in particular more than two auxiliary units, which are also electrically supplied via the auxiliary power output (or output terminal) 17 of the energy supply device 10. The direct current input (DC input) of the electrolyzer 22 is connected to the direct current output (or output terminal) 16 of the energy supply device 10 and is supplied with a direct current by this device. The auxiliary units 23, 24 are supplied with an alternating voltage by the energy supply device 10 via the auxiliary power output 17. The control unit 25 of the electrolysis unit controls the electrolyzer 22 and the auxiliary units 23, 24.

[0045] In one embodiment, the control unit (e.g., circuit) 30 of the electrolysis installation 50 issues control commands to both the energy supply device 10 and the electrolysis unit 20, and operates as a higher-level control unit during operation of the electrolysis installation 50. The control unit 30 thus enables the energy supply device 10 and the electrolysis unit 20 to be controlled in such a way that smooth operation of the electrolysis unit 20 is ensured. The higher-level control unit 30 is shown in FIG. 3 as a separate component. Alternatively, however, it is also possible for higher-level control functions to also be processed within the control unit 13 of the energy supply device 10 and/or the control unit 25 of the electrolysis unit 22. In this case, it is possible for the higher-level control unit 30 to not be present as a separate component, but, rather, incorporated into at least one of the control units 13, 25.

[0046] In the following, an operation of the electrolysis installation 50 is described using the example of starting up the electrolysis installation 50. For this purpose, it is assumed that all AC isolation units 3, 5 and all DC isolation units 11, 12 are open (e.g., creating an open circuit condition in the respective conduction path). Furthermore, the transformation ratios of the transformers 2, 4 are selected, by way of example, such that the following holds for the voltage amplitudes: .Math..sub.2, .Math..sub.3, .Math..sub.4: .Math..sub.2>.Math..sub.4>.Math..sub.3. The first voltage amplitude .Math..sub.1 is set to a value required to supply the auxiliary units 23, 24, e.g., 400 V or 480 V, via the transformation ratio assigned to the first secondary-side connection 2S1 of the first multi-winding transformer 2. It is usually smaller than the second voltage amplitude U.sub.2. It can optionally also be smaller than the fourth voltage amplitude U.sub.4, or possibly also smaller than the third voltage amplitude U.sub.3. First, the AC isolation units 3 are closed (e.g., enabling current conduction along the respective conduction path), whereby an alternating voltage of voltage amplitude .Math..sub.1 is generated via the first secondary-side connection 2S1 and provided to the auxiliary units 23, 24 of the electrolysis unit 22. Controlled via the control unit 25 of the electrolysis unit 20, these units can therefore take over the chemical supply of the electrolyzer 22 and bring it into an operational state. Furthermore, the AC isolation unit 5 assigned to the third secondary-side connection 4S3, and, if applicable, the other AC isolation units 5 that are still open, are closed. The pre-charging means VL contained in the AC isolation units 5 now carries out a current-limited pre-charging of the output capacitor 9 assigned to the second AC/DC converter 7, and, if applicable, also of those output capacitors 9 assigned to the further AC/DC converters 6, 8. Due to the different voltage amplitudes .Math..sub.2, .Math..sub.3, .Math..sub.4, the minimum possible voltages applied to the output capacitors 9 can also be different. Subsequently, the DC isolation unit 12 having a pre-charging means or circuit VL is closed, whereby the DC input of the electrolyzer 22 is pre-charged via the second AC/DC converter 7. If the DC voltage U.sub.DC,EL provided via the second AC/DC converter 7 reaches or exceeds an open-circuit voltage U.sub.0 of the electrolyzer 20, an electrolysis reaction begins to take place therein.

[0047] In one embodiment, start-up and partial load operation of the electrolyzer 22 can be carried out with only the second AC/DC converter 7. An increasing power consumption of the electrolyzer 22 is controlled by a level of the DC voltage U.sub.DC,EL provided at the DC voltage output 16. If the DC voltage U.sub.DC,EL at the DC input of the electrolyzer 22 has sufficiently approached a DC voltage present at one of the further output capacitors 9, then the remaining DC isolation units 11, each of which is assigned to an AC/DC converter 6, 8 that is not yet connected to the electrolyzer 22, can be closed. Due to a sufficient approximation between a DC voltage applied to the output capacitors 9 and the DC voltage applied to the DC input of the electrolyzer 22, in one embodiment the corresponding DC isolation units 11 can each be designed without a pre-charging means or circuit VL.

[0048] The operation described above has been explained using the example of starting up the electrolysis installation 50 and a subsequent increase in power of the electrolyzer 22, in which the AC/DC converters 6, 7, 8 are successively connected to the electrolyzer 22 via the DC isolation units 11, 12 assigned to them. If the power of the electrolyzer 22 decreases, the AC/DC converters 6, 7, 8 can be separated again (e.g., disconnected from the conduction path) in reverse order by opening the corresponding DC isolation units 11, 12.