Energy supply device for an electrolyzer, electrolysis device, and method for controlling the energy supply device

Abstract

The invention relates to an energy supply device (1) for an electrolyzer (10). The energy supply device (1) has an input circuit (2) and a transformer (3). The input circuit (2) is designed to be connected to an energy source (4) or an energy supply network. In order to improve the energy supply device (1), the input circuit (2) is additionally designed to provide at least two different electric potentials at contacts (5), and the converter (3) is electrically connected to at least one of the contacts (5) on the input side by means of a respective conductor (6). The energy supply device (1) is designed to change the contact (5) connected to the converter (3) by reconnecting at least one conductor (6) of the energy supply device (1). The invention additionally relates to an electrolysis device comprising such an energy supply device (1) and an electrolyzer (10) and to a method for controlling such an energy supply device (1) or such an electrolysis device (100), wherein the converter (3) is operated using a voltage level produced by the input circuit, and at least one conductor (6) of the energy supply device (1) is manually reconnected from a first contact of the contacts (5) to a second contact of the contacts (5) in order to change the voltage level.

Description

[0001] Description

[0002] POWER SUPPLY DEVICE FOR AN ELECTROLYSER, ELECTROLYSIS DEVICE AND METHOD FOR CONTROLLING THE POWER SUPPLY DEVICE

[0003] The invention relates to a power supply device for an electrolyzer, wherein the power supply device has an input circuit and a power converter, wherein the input circuit is designed to be connected to a power source or a power supply network. Furthermore, the invention relates to an electrolysis device having such a power supply device and an electrolyzer. The invention further relates to a method for controlling such a power supply device or such an electrolysis device and to a use of such a power supply device or such an electrolysis device for the production of hydrogen.

[0004] With the help of an electrolyzer, a material transformation can be brought about as a chemical reaction. This involves electrolysis. The electrolyzer is supplied with electrical energy from an energy source. An alternating voltage from the energy source is converted into a direct voltage for the electrolyzer by means of a power converter. This power converter is therefore also called a rectifier. Line-commutated power converters such as diode rectifiers or thyristor power converters, also known as thyristor-controlled power converters, are used as power converters. Alternatively, or in combination with these, self-commutated power converters, for example those based on IGBTs, are used. These self-commutated power converters are also called pulsed power converters due to their pulsed operation.

[0005] To adapt to different voltage levels of energy source and electrolyzer, a transformer is often used, which is arranged between energy source and electrolyzer.

[0006] In the following, the term "voltage level" refers to a voltage level. A measure of the voltage level is, for example, the amplitude for a sinusoidal voltage waveform or the effective value for a periodic voltage waveform.

[0007] In the future, electrolysis will become increasingly important for the economical and environmentally friendly production of hydrogen, for example, as a synthetic fuel. Hydrogen is produced using an electrolyzer or a corresponding electrolysis device. This hydrogen-based fuel can significantly contribute to reducing climate-damaging CO2 emissions.

[0008] The invention is based on the object of improving the energy supply for an electrolyzer and for an electrolysis device.

[0009] This object is achieved by a power supply device for an electrolyzer, wherein the power supply device has an input circuit and a power converter, wherein the input circuit is designed to be connected to an energy source or a power supply network and to provide at least two different electrical potentials at contacts, wherein the input circuit comprises a transformer (7) for adjusting the voltage level, wherein on the power converter side the transformer (7) is connected to an autotransformer (8), wherein the autotransformer has at least two contacts for providing different electrical potentials, wherein the power converter is electrically connected on the input side by means of a respective conductor to at least one of the contacts, wherein the power supply device is designedthat a change of the contact connected to the power converter takes place by manually reconnecting at least one conductor of the power supply device. This object is further achieved by an electrolysis device comprising such a power supply device and an electrolyzer, wherein the power converter is electrically connected to the electrolyzer on the output side. This object is further achieved by a method for controlling such a power supply device or such an electrolysis device, wherein the power converter is operated with one of the voltage levels generated by the input circuit, wherein to change the voltage level, at least one conductor of the power supply device is manually reconnected from a first contact of the contacts to a second contact of the contacts.

[0010] Furthermore, this object is achieved by the use of such an energy supply device or such an electrolysis device for producing hydrogen by electrolysis.

[0011] Further advantageous embodiments of the invention are specified in the dependent claims.

[0012] The invention is based, inter alia, on the finding that the operation of an electrolyzer can be significantly improved by the proposed structure of the energy supply device for the electrolyzer and by an electrolysis device with a corresponding energy supply device if the effect of ageing due to the operation of the electrolyzer is taken into account.

[0013] Electrolyzers are subject to ageing during operation. It can be observed that the performance of the electrolyzer, in particular the amount of the desired electrolysis product such as hydrogen produced per unit of time, decreases over time. To counteract this effect, it has proven advantageous to increase the DC voltage at the electrolyzer over time in order to generate the same current flow that leads to an unchanged amount of electrolysis product to be produced. In this case, the output voltage of the power converter, the DC voltage, is increased accordingly. With the increased voltage at the electrolyzer at constant current, the power transmitted by the power converter increases. This analogously increases the active power at the input of the power converter. Due to the constant mains voltage, the increased active power leads to an increased input current at the power converter.This increased current on the input side and the increased voltage on the output side are taken into account in the design and dimensioning of the semiconductors of the power converter and lead to an over-dimensioning of these components.

[0014] With increasing age, the firing delay angle a of a thyristor converter decreases. In a pulse-controlled converter, a higher output voltage leads to a lower modulation depth m, also known as the duty cycle, in order to adjust the output voltage. The corresponding converter cannot therefore be operated at the optimum operating point over its entire service life, particularly with regard to its input-side variables.

[0015] With a larger firing delay angle, especially at the beginning of the service life, the reactive power of the thyristor converter also increases. This means that a larger firing delay angle also results in a larger input current on the input side due to the reactive current, necessitating correspondingly larger semiconductor dimensions. Therefore, it has proven advantageous for dimensioning to keep the operating range of the firing delay angle α low and at small values ​​over the service life.

[0016] The control level of a pulse-controlled converter is limited by the diodes and the boost converter operation. For a given output voltage of the converter, a maximum input voltage results.

[0017] Thus, the power converter is not optimally utilized throughout its entire service life, and especially at the beginning of its service life. To compensate for these changing properties over its service life, the power converter, particularly the semiconductors within it, are oversized.

[0018] The energy supply device is designed to be connected to an energy source. The energy source can be in the form of a voltage source, for example. The energy source can be part of an energy supply network, so that the energy supply device is also designed for connection to an energy supply network. The energy supply network can be in the form of an interconnected network or an isolated network. It is also possible for the voltage source to be formed, for example, by an energy generation plant such as a wind turbine or a solar power plant, which contributes to the environmentally friendly production of hydrogen. An energy source with an inherent fluctuation in energy production is particularly suitable for electrolysis, since peak power due to high wind speeds or high levels of solar radiation can also be advantageously used for hydrogen production.This results in a particularly high utilization of renewable energy sources and contributes to a particularly environmentally friendly production of the energy source hydrogen.

[0019] In order to be able to use and operate the power converter more effectively, the invention proposes making the input voltage of the power converter variable in such a way that the input circuit of the energy supply device has different electrical potentials at different contacts. Different voltage levels can be created using these different electrical potentials. The different voltage levels result, for example, as a difference between different electrical potentials between different contacts or as an electrical potential compared to a reference potential that is present at the input circuit and the power converter. The reference potential can be, for example, the earth potential or the potential of a star point of a multi-phase voltage system. The input of the power converter can therefore be connected to different voltage levels.The input circuit generates the different electrical potentials from the mains voltage and applies them to different contacts. One possible way of generating these potentials is, for example, using a transformer or a transformer in combination with a voltage divider such as an autotransformer.

[0020] If the converter is powered on the input side by a three-phase energy or voltage source, three contacts are advantageously provided for each voltage level. Individual contacts can be used in different combinations to generate different voltage levels. When powered by a single-phase energy or voltage source, only one contact is required for each voltage level.

[0021] Different voltage levels can differ, for example, in their amplitude or in their effective voltage value. Since aging is a slow process, in a simple application, the input circuit can provide two different voltage levels at one contact each, relative to a reference potential, or at three contacts in a three-phase system. This means that switching between these voltage levels is only necessary once during the entire service life.

[0022] Because the voltage levels change extremely rarely over the entire service life, it has proven advantageous if the voltage levels are changed by manually reconnecting at least one conductor between the power converter and the input circuit. During manual reconnection, an electrical connection is broken using a suitable tool and a new electrical connection is created. The power supply device is set up so that the contact connected to the power converter is changed by manually reconnecting at least one conductor of the power supply device in such a way that the voltage level at the input-side connections of the power converter changes. The conductor can be designed as a cable or busbar, for example. This means that there is no need for a costly switching device, in particular an automated switching device.The advantage of the low cost of such an adjustment of the input voltage of the power converter outweighs the disadvantage that the electrolysis process, i.e. the operation of the electrolyzer, has to be interrupted for the duration of the manual reconnection in order to ensure the safety of the operating personnel, in particular the safety against contact.

[0023] For example, in a pulse-controlled converter, the use of different voltage levels leads to a reduction in the input current, which results from the increased active power. Furthermore, in a thyristor converter, the load on the semiconductors is reduced by a reduction in reactive power due to the narrower operating range of the trigger delay angle.

[0024] Manual reconnection has proven particularly advantageous for power supply devices where the voltage levels that can be generated are in the medium voltage range. The medium voltage range covers an alternating voltage of more than 1000 V and a direct voltage of more than 1500 V. In this case, devices for automated switching would be particularly large and expensive. Likewise, safety regulations make this type of automated switching complex and expensive. Because reconnection is required infrequently, manual reconnection allows a particularly cost-effective power supply device with small structural dimensions to be specified and implemented, particularly at voltage levels in the medium voltage range. The risk of incorrect operation is therefore also low.Even if the input circuit generates a variety of voltage levels and makes them available at a corresponding contact, the number of reconnections over the lifetime is still very low. Manual reconnection is preferably performed after an operating time of more than one year, especially after three or five years. Assuming that there will be an interruption in operation at set times, for example, due to maintenance work on the electrolyzer, manual reconnection does not significantly impair the electrolysis process, as it can be performed during one of the maintenance periods.

[0025] Different voltage levels can be generated easily, for example, by means of a transformer, an autotransformer, or a voltage divider. The transformer or autotransformer can have two or more taps on a winding, at which a different voltage level is applied compared to a reference potential. The transformer and / or the voltage divider thus generates at least some of the different electrical potentials that are applied to the respective contacts. These taps then each form a contact in the input circuit. A voltage divider, designed with low losses, for example as an inductive or capacitive voltage divider, can also be used to generate different voltage levels.The advantage of these components is that they are standard electrical components that are simple, reliable and, above all, cost-effective compared to switching devices.

[0026] The generation of different voltage levels can also be achieved by combining transformers, in particular transformers with multiple taps, and one or more voltage dividers.

[0027] The proposed design of the power supply device is particularly advantageous for thyristor power converters. The proposed design reduces the bandwidth of the firing delay angle α with which the power converter is operated. In other words, the power converter is operated closer to its optimum of o « 0° and the deviation from this operating point is smaller. In addition to the advantageously high utilization of the active power of the power converter, the reactive power at the AC side input of the power converter is also reduced at the same time. The input current is reduced both by the lower active current and the lower reactive current. The proportion of active current in the total current at the input of the power converter is therefore particularly high. This also leads to particularly good utilization of the thyristor power converter and enables application-specific dimensioning of the power converter.

[0028] The proposed design is also particularly advantageous for a pulse-controlled converter with self-commutated semiconductors, as it enables operation at an optimum modulation level. As this type of converter is a boost converter circuit, the input voltage of a converter must not be greater than approximately half the minimum required output voltage. Up to now, converters have been dimensioned so that the input voltage always corresponds to this low value. This means that the converter operates with a decreasing modulation level as the electrolyzer ages and its output voltage increases. The mains current, i.e. the input current, of the converter is based on the current power and mains voltage and determines the necessary current carrying capacity of the semiconductor switches.Therefore, the power semiconductors are oversized to accommodate the output voltage variation. This is because, as the duty cycle decreases, the utilization of the available semiconductors in the converter decreases significantly, meaning that the existing elements are not optimally utilized. Furthermore, design reserves at an optimal duty cycle can be used to perform additional functions, such as reactive power control to support the power grid in the event of a fault.

[0029] The proposed method and device can be used particularly advantageously for the production of hydrogen. Due to the relatively low voltage of 1 to 2 volts between the electrodes, even a small change in the voltage between the electrodes represents a large relative change. If a large number of electrodes are then arranged in series in the electrolyzer, a large voltage range is obtained, which can be covered by the output voltage of the power converter, especially when producing hydrogen by electrolysis.

[0030] As previously explained, this requires a corresponding over-dimensioning of the semiconductors. The operation of the electrolysis device can be carried out significantly more efficiently with the proposed design, since such over-dimensioning is no longer necessary. Thus, the proposed method is particularly suitable as a method for generating hydrogen using such a power supply device or such an electrolysis device.

[0031] In an advantageous embodiment of the invention, the electrolysis device has a plurality of electrolyzers, the electrolyzers being arranged in a series circuit, the series circuit being electrically connected to the power converter of the energy supply device. In particular in electrolysis for generating hydrogen, it has proven advantageous to arrange several pairs of electrodes within an electrolyzer in a series circuit or, alternatively or additionally, to arrange a plurality of electrolyzers in a series circuit. This allows available power electronics elements to be used in a simple manner for generating hydrogen by adapting the electrolyzers to the available power converters using the series circuit.Corresponding converters are available for output voltages ranging from a few hundred volts up to over 1000V and even over 1500V, and even beyond, in the medium-voltage and high-voltage ranges. These converters can be used to implement a cost-effective electrolysis device and produce hydrogen economically.

[0032] In a further advantageous embodiment of the invention, the electrolysis device is designed to produce hydrogen. Due to the relatively low decomposition voltage of water, changes in the voltage required by the electrolyzer due to aging have a relatively strong effect on the output voltage of the power converter. Thanks to the proposed design, the power converter can nevertheless be operated over large periods of its service life at an economical operating point at which the semiconductors are highly utilized and oversizing is only required to a small extent. This makes it possible to eliminate the problems relating to the energy supply to the electrolyzer in a simple and economical way. The electrolysis device is therefore particularly suitable for producing environmentally friendly hydrogen.

[0033] In a further advantageous embodiment of the invention, when the voltage level changes, energy transfer from the input circuit to the power converter is interrupted in a first step, the conductor of the energy supply device being manually reconnected in a second step, and energy transfer from the input circuit to the power converter being restored in a third step. Compared to an automated switching operation, for example using a switching device or a contactor, the proposed method is slow. Since the switching operation, the manual reconnection, only has to be carried out very rarely, a time for maintenance, in particular the maintenance of the electrolyzer, can be scheduled for the reconnection operation. At the time of maintenance, the electrolysis device is switched off in order to carry out maintenance work on components such as the electrolyzer.For maintenance, the power supply is also interrupted in a similar way to the first step of the proposed procedure. The third step, restoring power transmission, is also part of the maintenance, creating a synergy between the maintenance work and the voltage level adjustment. Manual reconnection can then be performed as part of the maintenance or, alternatively, in parallel with the maintenance work on the electrolyzer or its power supply device. Furthermore, these procedural steps ensure contact safety during maintenance work and the reconnection process.

[0034] In a further advantageous embodiment of the invention, the method is started when the output voltage of the power converter exceeds a specified limit value. In order to ensure efficient operation of the electrolyzer, a limit value can be specified, for example as a function of aging and / or measured current values, in particular measured current values ​​at the AC-side terminals of the power converter, at which limit the voltage level is changed. In this case, for example, a voltage level with a higher voltage or higher voltages is selected for feeding the power converter. This not only reduces the input currents, i.e. the AC-side currents, of the power converter, but also increases the efficiency of the energy supply device due to a low degree of modulation.This procedure also allows the converter to be operated with only a small bandwidth of the firing delay angle a and thus with a low reactive power component.

[0035] The invention is described and explained in more detail below with reference to the exemplary embodiments shown in the figures. They show:

[0036] FIG 1 to FIG 6 embodiments of a power supply device and electrolysis device. FIG 1 shows an electrolysis device 100. This has an electrolyzer 10 which is supplied with electrical energy from a power supply device 1. This electrical energy is transmitted with a direct voltage. For this purpose, the power supply device 1 is electrically connected to a power source 4. The power source 4, for example designed as a voltage source, can be part of a power supply network. The power supply device 1 comprises an input circuit 2 and a power converter 3. The input circuit 2 generates different electrical potentials from the voltage of the power source 4, which potentials are each applied to one of the contacts 5. Some of the contacts 5 are connected by means of conductors 6 to one of the AC voltage-side connections of the power converter 3.The power converter 3 can thus be connected to different voltage levels via different contacts 5. To change the voltage level, at least one conductor 6 must be detached from a first contact of the contacts 5 and connected to a second contact of the contacts 5. The power converter 3 generates a direct voltage at the output of the power converter 3 from the alternating voltage at the AC-side input of the power converter 3. This direct voltage is used to supply the electrolyzer 10.

[0037] The different electrical potentials of the contacts 5 and the associated different voltage levels between the contacts 5 and with respect to a reference potential, in particular the earth potential or the star point of a multi-phase voltage system, are generated in this exemplary embodiment by means of a transformer 7 which has a plurality of taps on the secondary side, each of which is electrically connected to a respective contact 5. With, for example, three electrical contacts 5, up to three voltage levels can thus be generated between two of the three contacts 5. In addition, three further voltages can be generated between one of the contacts 5 and a reference potential. A change in the voltage level connected to the power converter 3 is achieved by manually reconnecting at least one conductor 6 from a first contact to a second contact.According to the invention, the reconnection is carried out manually, so that switching devices that implement automated switching are not required.

[0038] In this exemplary embodiment, a single-phase power supply device with a fixed reference potential or a two-phase power supply device 1 is shown. Alternatively, the contacts 5 or a portion of the contacts 5 can form a three-phase voltage system for connection to a three-phase power converter 3.

[0039] 2 shows a further exemplary embodiment of a power supply device 1 and an electrolysis device 100. To avoid repetition, reference is made to the description of FIG. 1 and to the reference symbols introduced there. Instead of the transformer 7 in FIG. 1, a voltage divider 8 is provided in the input circuit 2 in FIG. 2 for generating different electrical potentials at the contacts 5. This can, as shown, be designed as an autotransformer. In order to change the voltage level, a conductor can be reconnected from one contact 5 to another contact 5. As an alternative to the autotransformer, the voltage divider 8 can also be designed as an inductive voltage divider with at least two inductors. Alternatively, the voltage divider 8 can also be designed as a capacitive voltage divider with at least two capacitors.Furthermore, the voltage divider 8 can alternatively be designed as an ohmic voltage divider with at least two resistors.

[0040] The illustrated single-phase or two-phase configuration of the input circuit 2 and the power converter 3 can also be replaced by a multi-phase, in particular a three-phase, configuration. The three-phase configuration allows the voltage utilization of the power converter 3 to be further improved, for example, by using a zero-sequence system.

[0041] 1 and 2 and to the reference numerals introduced there. In this exemplary embodiment, different contacts 5 of the input circuit 2 are connected to the power converter 3 by means of the conductors 6 compared to the exemplary embodiments in FIGS. 1 and 2. This arrangement supplies an input voltage with a lower amplitude to the power converter 3. This circuit is therefore suitable for operating the electrolyzer 10, particularly at the beginning of its service life. As the electrolyzer 10 ages, the need for a higher direct voltage arises at the input of the electrolyzer 10 and thus at the output of the power converter 3.As soon as this higher output voltage can no longer be generated by the power converter 3, because, for example, the modulation depth has already reached its minimum or the firing delay angle α has already assumed a value of α~0, a higher input voltage is applied to the input of the power converter 3 by reconnecting at least one conductor 6 of the conductors 6. Now, with advancing age, a higher output voltage can be generated at the power converter 3 with low losses and efficiently, without generating an unacceptably high reactive current component. Likewise, the semiconductors of the power converter 3 are optimally utilized by the reconnection option. During the reconnection process, at least one conductor 6 is disconnected from the contact 5 to which it is connected and connected to another contact 5. This process is referred to as reconnection if it is carried out manually.In a single-phase or two-phase design of the power converter 3, it is often sufficient to reconnect just one conductor 6. In a multi-phase design of the power converter 3, in particular in a three-phase design of the power converter 3, it has proven advantageous, although not necessary, to reconnect three conductors 6 to other contacts 5. As a criterion for detecting advanced aging, which makes reconnection advantageous, the exceeding of a current limit value at the input of the power converter 3 has proven advantageous. Alternatively, the reconnection can take place when a predetermined value is reached for the modulation depth, for example close to m=1, or for the firing delay angle, for example close to a=0. In this case, close to a=0 refers, for example, to an angular range of up to 5° or up to 10°.In this case, a condition for triggering the re-clamping process is defined by means of the modulation degree m or the ignition delay angle a.

[0042] In order to enable the most finely stepped switching possible in a three-phase arrangement, it has proven advantageous to reconnect only one conductor 6, even in a three-phase arrangement. The asymmetries occurring in the three-phase voltage network, for example, recognizable by a phase difference of other than 120°, can be compensated by the converter 3.

[0043] After reconnecting, the configuration is as shown in one of Figures 1 or 2.

[0044] FIG. 4 shows a three-phase embodiment of the input circuit 2 and thus also of the energy supply device 1. To avoid repetition, reference is made to the description of FIGS. 1 to 3 and to the reference symbols introduced there. The transformer 7 and the voltage divider 8 can also be used in the input circuit 2. The transformer 7 adapts the voltage of the energy source 4 to the voltage level of the energy supply device 1 and creates a galvanic isolation from the energy source 4 or the energy supply network. The different electrical potentials at the contacts 5 are then generated with the aid of a voltage divider 8, in this example designed as an autotransformer. Alternatively, the voltage divider 8 can be dispensed with if the transformer has corresponding taps.

[0045] During a reconnection process, the conductors 6 in all three phases can be reconnected to a different contact 5. The power converter 3 is then supplied with a symmetrical three-phase voltage system on the input side. Alternatively, it is also possible to reconnect exactly one conductor 6 or exactly two conductors 6 during a reconnection process. This does create an asymmetrical three-phase voltage system, from which the power converter 3 can nevertheless draw electrical energy without any problems. The advantage of not reconnecting the conductors in all three phases during a reconnection process is that the voltage level can then be adjusted even more finely to the then existing state of aging. Thanks to these finely incremented voltage levels, the reconnection can be adapted to other maintenance work, for example maintenance work on the electrolyzer 10, since an optimal voltage level can be applied to the input side of the power converter 3 at the time of maintenance.This applies to all three-phase arrangements, regardless of how the different electrical potentials are generated.

[0046] FIG. 5 shows that the transformer 7 and the voltage divider 8 can generate a large number of different electrical potentials, with which a large number of voltage levels can be generated to supply the power converter 3. To avoid repetition, reference is made to the description of FIGS. 1 to 4 and to the reference symbols introduced there. For this purpose, the transformer 7 or the autotransformer as a voltage divider 8 has, for example, a large number of taps. Likewise, regardless of the design of the energy supply device 1, it is possible to supply a plurality of electrolyzers 10 with electrical energy using one energy supply device 1. The electrolyzers 10 can be arranged in a series circuit 101.The arrangement in a series circuit 101 intensifies the effect of aging, which requires an increased voltage to be applied to the electrolyzers 10 over the course of their service life. This disadvantage can be easily eliminated by the simple possibility of different voltage levels. The arrangement of several electrolyzers 10 on a power supply device 1, for example in a series circuit 101, can also be carried out for the embodiments of Figures 1 to 4.

[0047] FIG. 6 shows the design of the electrolysis device 100 and thus also the design of the energy supply device 1 with a three-phase voltage system. Both the input circuit 2 and the power converter 3 are three-phase. This achieves a uniform energy absorption from the energy source 4 or the energy supply network. If, during a reconnection, only one conductor 6 is reconnected from a first contact 5 to a second contact 5, this does indeed result in uneven energy absorption in the individual phases and thus also in uneven loading of the energy source 4 or the energy supply network, but at the same time, a particularly fine gradation of the individual voltage levels can be achieved.The load on the network is reduced again by the many voltage levels, so that this arrangement results in a particularly advantageous implementation without over-dimensioning of the energy supply device 1 with only a slight increase in load and thus a tolerable load for the energy source 4.

[0048] In summary, the invention relates to a power supply device 1 for an electrolyzer 10, wherein the power supply device 1 has an input circuit 2 and a power converter 3, wherein the input circuit 2 is designed to be connected to a power source 4 or a power supply network. In order to improve the power supply device 1, it is proposed that the input circuit 2 is further designed to provide at least two different electrical potentials at contacts 5, wherein the power converter 3 is electrically connected on the input side by means of a respective conductor 6 to at least one of the contacts 5, wherein the power supply device 1 is designed such that a change of the contact 5 connected to the power converter 3 takes place by reconnecting at least one conductor 6 of the power supply device 1.Furthermore, the invention relates to an electrolysis device with such a power supply device 1 and an electrolyzer 10. The invention further relates to a method for controlling such a power supply device 1 or such an electrolysis device 100, wherein the power converter 3 is operated with one of the voltage levels generated by the input circuit, wherein in order to change the voltage level, at least one conductor 6 of the power supply device 1 is manually reconnected from a first contact of the contacts 5 to a second contact of the contacts 5.

Claims

Patent claims 1. Energy supply device (1) for an electrolyzer (10), wherein the energy supply device (1) has an input circuit (2) and a power converter (3), wherein the input circuit (2) is designed to be connected to a power source (4) or a power supply network and to provide at least two different electrical potentials at contacts (5), wherein the input circuit comprises a transformer (7) for adjusting the voltage level, wherein on the power converter side, the transformer (7) is connected to an autotransformer (8), wherein the autotransformer has at least two contacts for providing different electrical potentials, wherein the power converter (3) is electrically connected on the input side by means of a respective conductor (6) to at least one of the contacts (5), wherein the energy supply device (1) is designed,that a change of the contact (5) connected to the power converter (3) is carried out by manually reconnecting at least one conductor (6) of the power supply device (1).

2. Electrolysis device (100) comprising a power supply device (1) according to claim 1 and an electrolyzer (10), wherein the power converter (3) is electrically connected to the electrolyzer (10) on the output side.

3. Electrolysis device (100) according to claim 2, wherein the electrolysis device (100) comprises a plurality of electrolyzers (10), wherein the electrolyzers (10) are arranged in a series circuit (101), wherein the series circuit (101) is electrically connected to the power converter (3) of the power supply device (1).

4. Electrolysis device (100) according to one of claims 2 or 3, wherein the electrolysis device (100) is configured to generate hydrogen.

5. Method for controlling a power supply device (1) according to claim 1 or an electrolysis device (100) according to one of claims 2 to 4, wherein the power converter (3) is operated with one of the voltage levels generated by the input circuit, wherein in order to change the voltage level at least one conductor (6) of the power supply device (1) is manually reconnected from a first contact of the contacts (5) to a second contact of the contacts (5).

6. The method according to claim 5, wherein, upon a change in the voltage level, in a first step, energy transmission from the input circuit (2) to the power converter (3) is interrupted, wherein in a second step, the conductor (6) of the power supply device (1) is manually reconnected, wherein in a third step, the energy transmission from the input circuit (2) to the power converter (3) is restored.

7. Method according to one of claims 5 or 6, wherein the method is started when the output-side voltage of the power converter (3) exceeds a specified limit value.

8. Use of an energy supply device (1) according to claim 1 or an electrolysis device (100) according to one of claims 2 to 4 for producing hydrogen by electrolysis.

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