Electrolysis apparatus and apparatus assembly comprising electrolysis apparatus and renewable energy apparatus

Abstract

The invention relates to an electrolysis device (1) comprising an electrolysis cell (3) and a circuit arrangement (5) having an input (7) for connection to a power source and an output (9) connected to the electrolysis cell (3), the circuit arrangement (5) having an electrical filter mechanism (11), the filter mechanism is designed so as to be able to attenuate high-frequency signal components, in particular from an external power source, very effectively. The invention also relates to a plant assembly (100) having an electrolysis plant (1) and a renewable energy plant (50). In this case, a power supply having an output (52) is formed by the renewable energy source device (50), and the electrolysis device (1) is directly connected to the output (52) of the renewable energy source device (50).

Description

Technical Field

[0001] The invention relates to an electrolysis device comprising an electrolysis cell and a circuit arrangement. The invention also relates to a device complex comprising an electrolysis device and a renewable energy device connected to the electrolysis device. Background Art

[0002] An electrolysis device is a device that performs a material conversion (electrolysis) by means of an electric current. Corresponding to the variety of different electrochemical electrolysis processes, there are also a variety of electrolysis devices, such as electrolysis devices for water electrolysis.

[0003] Nowadays, hydrogen is produced from water, for example, by proton exchange membrane (PEM) electrolysis or alkaline electrolysis. Electrolysis plants produce hydrogen and oxygen from supplied water with the aid of electrical energy. The process takes place in an electrolysis stack consisting of a number of electrolysis cells. In the electrolysis stack, which is under direct current voltage (DC voltage), water is introduced as a reactant, wherein two fluid streams consisting of water and gas bubbles (O2 or H2) emerge after passing through the electrolysis cells.

[0004] The idea is to use excess energy from renewable energy sources to produce valuable substances during periods of high sunshine and high wind, i.e. above-average solar or wind power generation. One valuable substance can be hydrogen produced by water electrolysis plants in particular. Based on hydrogen, for example, so-called renewable energy gas, also called EE gas, can be produced. EE gas is a combustible gas obtained with the aid of electrical energy from renewable energy sources.

[0005] Hydrogen is a particularly environmentally friendly and sustainable energy carrier. It has the unique potential to achieve a CO2-free energy system, transport and large parts of the chemical industry. In order to achieve this, however, the hydrogen must not come from fossil energy sources but must be produced with the help of renewable energy sources. At least an increasing amount of electricity generated from renewable energy sources is now fed into the public grid. Therefore, if the electrolysis plant is operated with electricity from the public grid, a corresponding proportion of green hydrogen can be produced depending on the power mix.

[0006] In electrolysis performed on an industrial scale, direct current is mainly supplied via rectifiers supplied from the grid. During the rectification of the AC voltage on the grid side, harmonics may be generated due to the way the rectifiers work, which may put stress on the AC grid and / or the DC grid.

[0007] Such an electrolysis device is disclosed in EP 3 723 254 A1, which is connected to a public power grid and is accordingly powered by the power grid. For this purpose, the electrolysis device has a circuit device, which includes four coil devices and four rectifiers. Here, the first coil in the coil device is respectively connected to the DC voltage side of one of the rectifiers. The circuit device also includes two transformers, each of which has a primary winding and two secondary windings. The primary winding of the transformer is connected to a power grid, such as a medium-voltage power grid or a high-voltage power grid. In this way, although the iron content in the first coil is reduced, the desired smoothing of the DC current in the transformer or the attenuation of harmonics can still be achieved.

[0008] One of the sources of renewable energy is the increasing use of wind power. In particular, large electrical powers can be achieved using so-called offshore wind power plants close to the coast. However, it is challenging to cover large distances to the loads. Therefore, the energy should be delivered to the loads with as few losses as possible. Hydrogen is very suitable as a transport medium and energy carrier. For example, hydrogen can be transported in gaseous form via pipelines. The advantage here is that the hydrogen pipeline can also fulfill the function of an energy storage device, since the internal pressure can be varied within a certain range.

[0009] Based on these considerations, it is of particular economic interest to produce hydrogen directly at the energy generation site, i.e. in a self-sufficient manner and independent of the public grid. For this purpose, it is proposed to install electrolysis plants on offshore platforms in the maritime sector directly at or near the offshore wind power plant and to use the generated electricity for power supply.

[0010] For the mainland, it is also proposed to directly produce hydrogen using electricity from onshore wind power plants or photovoltaic plants, at least partially by direct connection to and feeding into the electrolysis plant. In all these applications, the electrolysis plant is part of an island grid. That is to say, the electrolysis current is not obtained from the public grid, but is provided directly by the wind power plant or PV (photovoltaic) plant and fed into the electrolysis cell of the electrolysis plant. Compared with the above-mentioned grid-fed operation, this brings special challenges and problems with regard to the electrical connection and interconnection of the electrolysis plant with the corresponding EE generation plant (whether a wind power plant or a photovoltaic plant), in particular in order to ensure safe and, in particular, undisturbed operation of the electrolysis plant in a direct plant complex with the EE generation plant. Summary of the invention

[0011] It is therefore an object of the present invention to specify an electrolysis plant by means of which electricity from renewable energy sources can be fed directly and undisturbed into the electrolysis plant.

[0012] According to the invention, this object is achieved by an electrolysis device, which comprises an electrolysis cell and a circuit arrangement having an input for connection to a power supply and an output connected to the electrolysis cell, wherein the circuit arrangement has an electrical filter mechanism which is designed to attenuate high-frequency signal components.

[0013] The present invention is based on the following recognition: electrolysis equipment, in particular the PEM water electrolysis cell of the electrolyzer is very sensitive to high-frequency stray currents. These stray currents can be input into the electrolysis equipment through a ground connection or a ground link. Due to the necessary equipment components of the electrolysis equipment, such as process technology parts, gas separators, auxiliary systems, water supply pipelines, etc., a ground connection (ground link or ground loop) on the electrolysis side is not enough. Therefore, on the one hand, it is important to avoid that the current path will be closed by grounding, i.e., forming a ground link or ground loop. On the other hand, the input electromagnetic interference field itself should be avoided as much as possible or at least entrainment should be reduced. This problem is particularly evident when the electrolysis equipment is directly connected to a DC power supply, such as provided by a photovoltaic device or a wind energy device.

[0014] In this complex plant complex consisting of renewable energy generation equipment and electrolysis equipment, the EE directly feeds the electrolysis current for electrolysis, and the adverse effects of ground loops and the adverse effects of inputting alternating electromagnetic fields into the power electronic components used are correspondingly amplified. For example, in rectifiers that supply large currents for electrolysis, insulated-gate bipolar transistors (IGBTs) are widely and preferentially used. IGBTs generate strong interference signals, especially on the ground side. IGBTs are semiconductor components used in power electronics because they combine the advantages of bipolar transistors (such as good conduction properties, high cut-off voltage, robustness) and the advantages of field effect transistors (almost power-free control). For example, in the so-called three-phase B6 bridge circuit with an IGBT-based rectifier, very precise control and good rectification of the electrolysis current are achieved. The significant advantages of IGBTs are high voltage limits and high current limits: voltages up to 6500V and currents up to 3600A and powers up to several megawatts, which makes IGBTs very suitable for electrolysis equipment.

[0015] By using the present invention, in an electrolysis device having the above-mentioned circuit device, a filter mechanism is provided on the DC side, thereby effectively filtering the interference signal generated by the high-frequency stray current between the external power supply and the electrolyzer of DC operation. It has been proved that the advantage of flexible coupling and direct connection to different power supplies is that the circuit device based on the filter is a component of the electrolysis device itself. A variety of connection options are inherently provided, and it is particularly advantageous to be independent of the power grid operation, especially island operation. Here, the original power supply or power supply can be both a DC power supply and an AC power supply, and it is advantageously directly provided by renewable energy. Through the filter mechanism, it is realized that the electrolyzer is supplied with stable DC power in particular without interference in two environments and applications. A particularly simple and flexibly adjustable solution is provided by the filter mechanism. Advantageously and appropriately, the self-powered systems and components of the electrolysis device, i.e. auxiliary systems, control devices, etc., can also be connected to the rear of the filter on the device side, and used to operate these systems and components, because high-quality DC power is already provided there. Through the present invention, the signal components of the external power supply itself, especially the high frequency, can be attenuated, and the electrolysis device can be connected to the external power supply to supply the electrolysis current. Furthermore, high-frequency signal components from other interfering power sources of the electrolysis system itself or in its surroundings, which may lead to interfering inputs, can also be filtered.

[0016] In the circuit arrangement, the filter mechanism advantageously acts in a manner similar to a mains filter in its mode of operation and can be designed accordingly in a specially adapted manner for use in an electrolysis device. In the present case, the filter mechanism can then be designed, for example, as an electrical circuit which both limits the entry of electrical interference from the electrical mechanism and components of the electrolysis device with an electrolysis cell into the power supply (radio interference removal) and significantly improves the electromagnetic compatibility of the electrolysis device and the protection against interference from the feed power supply. The latter leads to an improved interference resistance of the electrolysis device. This is particularly interesting and advantageous in applications in which electricity from renewable energy sources is fed directly and interference-free into the electrolysis device as direct current (i.e., direct feed or DC feed from a renewable energy device).

[0017] In this circuit arrangement, the filter mechanism can be optionally designed as a low-pass filter and include an inductor and a capacitor. The application field for directly connecting and supplying electrolytic current to the electrolyzer in the electrolysis equipment is preferably the medium voltage and low voltage range, depending on the power supply. As a component of the circuit arrangement, the filter mechanism is advantageously directly integrated into the electrolysis equipment that is particularly sensitive to interfering stray currents, or may be integrated into the live equipment parts that cause interference. Here, it is feasible and advantageous that the circuit arrangement with the filter mechanism is designed as a separate module that can be connected and integrated into the electrolysis equipment. Therefore, a filtered and interference-free DC voltage is ensured, that is, at the voltage or current level required and predetermined for electrolysis.

[0018] The circuit arrangement is therefore particularly advantageously designed as a filter mechanism and is designed to provide a direct current via an external power source, in particular an external DC power source, in order to supply the electrolysis cell with an electrolysis current. This is accomplished by coupling or connecting the input directly to the external power source, in particular to the external DC power source. As an external DC power source, a wind energy plant or a photovoltaic plant can advantageously be connected to the electrolysis plant, which can be advantageously designed for offshore and onshore applications, respectively, independently of the grid in so-called island operation.

[0019] In advantageous applications where an available external DC power source is used as the power source, this external DC power source can be connected directly and immediately via the input of the circuit arrangement, thereby achieving an undisturbed DC power supply to the electrolyzer. By filtering and decoupling by the filter mechanism provided in the circuit arrangement, harmful entrainment of high-frequency stray currents is reliably avoided, and thus ground currents and undesirable voltage losses in sensitive electrolyzers are avoided, in particular input to the electrolytic cell. Due to the reduction of losses caused by the stepped-down current path, safe operation of the electrolysis device is achieved with high reliability and an improved service life. At the same time, a simple and reliable direct connection of the electrolysis device to an energy generation device based on renewable energy sources can be achieved, and the desired operation independent of the power grid can be achieved.

[0020] In a particularly preferred embodiment, the filter device has a low-pass portion.

[0021] With a low-pass section or low-pass filter, it is particularly easy to realize together in a circuit arrangement that the high-frequency interference frequencies from the power supply are suppressed or filtered out and only the direct current required for electrolysis is switched on. Here, the low-pass filter can be designed as a passive, analog low-pass section, which, for example, has a resistor, a coil and a capacitor or a plurality of these electrical components. With additional active components, such as operational amplifiers or transistors, an active, analog low-pass section can also be provided in the filter mechanism. If digital signal processing is required, a time-discrete low-pass filter is implemented in a filter structure such as a FIR or IIR filter. This is accomplished using a digital circuit such as an FPGA or using a sequential computer program.

[0022] Low-pass filters for high power, high frequency and electrical energy technology (such as currently preferred for electrolysis equipment) are composed of capacitors and coils. They are usually found at the load output of frequency converters, class D amplifiers, switching power supplies and power supply filters.

[0023] In a preferred embodiment of the electrolysis device, the filter means is designed as a first-order low-pass section having an RC element.

[0024] In the simplest case, the low-pass section advantageously consists of a combination of a resistor and a capacitor (a so-called RC element) and forms a Butterworth filter of the first order. In the model describing the function, it is assumed that the source impedance of the input voltage of the filter is zero and the load impedance of the output voltage of the filter is infinitely high.

[0025] In an RC element, a possible jump change in the input voltage leads to an output voltage with the same jump height, but delayed by the time constant τ=RC in the curve of an exponential function, the so-called transfer function of the RC element.

[0026] In a particularly simple embodiment, alternatively or additionally, a simple coil or coil arrangement is also conceivable for attenuating, in particular, high-frequency signal components. This coil or coil arrangement is connected, for example, directly between the rectifier and the electrolyzer and carries the full load current during operation, i.e., the coil or coil arrangement is not grounded but connected to the rectifier and the electrolyzer.

[0027] The filter mechanism preferably has an inductance for attenuating high-frequency components.

[0028] In another preferred embodiment of the electrolysis device, the filter mechanism is designed as a second-order or higher-order low-pass section having at least one LRC low-pass section. Therefore, particularly effective filtering and interference elimination can be achieved for direct DC connection of the power supply to the electrolysis device.

[0029] By connecting the inductor L in series with the resistor R, a second-order low-pass section is advantageously obtained for the circuit arrangement, since its reactive impedance XL It also has frequency dependence, but it is related to the reactive impedance X of the capacitor. C Here, R is chosen to be large enough so that the voltage of the frequency response has no overshoot or only a small overshoot.

[0030] By connecting multiple low-pass parts in series in the circuit arrangement, the order of the low-pass part can also be advantageously increased. For example, two second-order low-pass parts connected in series form a fourth-order low-pass part. Here, the attenuation changes at 4×20dB / decade=80dB / decade above the cut-off frequency, which corresponds to a slope of 24dB / octave. However, two low-pass parts with the same cut-off frequency connected together will not produce a higher-order low-pass part of the same cut-off frequency. Relevant formulas and tables can be used to design a low-pass part with a desired cut-off frequency, which can be used according to the connection of the electrolysis device to an external power supply. In addition, there may be a problem that the low-pass part is affected by the output resistance of the upstream low-pass part and the input resistance of the downstream low-pass part in the link. This effect can be offset by impedance converters, which are additionally integrated into the circuit arrangement as needed. Usually, n storage elements, i.e. capacitors or coils, are provided for the n-order low-pass part in the circuit arrangement. The attenuation of the n-order low-pass part increases at n·20dB / decade above the cut-off frequency. In addition, preferably multiple parallel filters, particularly low-pass filters, can be used, and advantageously they are combined into a filter device connected to the electrolysis device. Here, the corresponding filters are set at different frequencies or frequency bands, and they are respectively to interfere with these frequencies or frequency bands.

[0031] In a preferred embodiment of the electrolysis device, the filter device is designed as an active filter, wherein the filter device has an operational amplifier.

[0032] Active low-pass sections can advantageously be implemented in the filter structure using operational amplifiers. The advantage of active low-pass sections is that the frequency response can be maintained even when a load is connected to the output. These low-pass sections can also be designed so that they only impose a minimal load on the power supply, so that the power supply impedance can be greater than zero.

[0033] In a particularly preferred embodiment of the electrolysis device, the electrolysis device comprises a rectifier which is connected to the input of the circuit arrangement on the output side and can be connected to an external AC power source on the input side, so that direct current without high-frequency signal components can be supplied to the electrolysis cell via the filter mechanism. From a technical point of view, direct current without high-frequency signal components also includes and comprises direct current that is largely or extremely free of high-frequency signal components.

[0034] Therefore, the electrolysis device is particularly advantageously equipped and arranged to be directly connected to an AC power source, for example, to a wind energy device, the generator of which supplies AC power. On the DC voltage side, i.e., at the output of the inverter, the inverter is connected to the circuit device. On the AC side, i.e., at the input of the inverter, the inverter can be connected to an external AC power source. By interconnecting the inverter with the circuit device, a connection of the electrolysis device with an AC power source to prevent interference is provided for the operation of the electrolysis device. In this application, the inverter may also be an integrated component of the circuit device. The circuit device then has an inverter and a filter mechanism for the AC power connection of the electrolysis device, and these two components advantageously act together. Thus, the electrolysis device is designed to be directly connected to an AC power source, such as a wind energy device in an island operation, directly on the AC side. Here, the electrolysis device is placed in close proximity to the wind energy device or integrated into a wind farm with a large number of wind energy devices.

[0035] Preferably, the rectifier is controllable and / or is designed as a three-phase rectifier, in particular the rectifier is designed as a B6 bridge rectifier.

[0036] The controllability of one or more rectifiers, which are advantageously designed as three-phase rectifiers or B6 bridge rectifiers, allows the total current generated via the one or more rectifiers to be adjusted and thus, for example, the operation of an electrolysis cell connected to the circuit arrangement to be precisely controlled.

[0037] In a preferred design of the electrolysis device, the filter mechanism is connected in series between the rectifier and the electrolyzer. The series connection of the rectifier and the electrolyzer represents a feasible and advantageous arrangement of the filter mechanism. Thus, the electrolyzer is protected from interfering inputs of high-frequency stray currents, for example via a ground loop. In this arrangement, the load current is completely carried by the filter mechanism.

[0038] In an alternative or additional preferred embodiment of the electrolysis device, a filter mechanism is connected to the rectifier, wherein the filter mechanism is connected to a reference potential, in particular to ground potential or to ground. As a result, the load current does not have to be carried by the filter mechanism. This alternative embodiment results in a particularly cost-effective solution.

[0039] In this embodiment, the filter device is connected with its input side directly to the DC side, i.e. the output of the rectifier, and on the second side to ground potential. The output of the rectifier is simultaneously connected to the electrolyzer, so that the output of the rectifier, the input of the filter device and the DC supply line of the electrolyzer are at the same potential.

[0040] In principle, it is also possible and advantageous in certain applications to combine the above-described series connection of the filter means with an alternative connection via ground potential in the circuit arrangement. However, it is usually preferred to design and select one of the two wiring options accordingly, since this is less complex and less costly to implement.

[0041] Another aspect of the invention is the design of the electrolysis device for preferably electrically connecting the electrolysis device to an external power source, in particular to an external DC power source, wherein the renewable energy device is directly electrically connected to the electrolysis device. This results in an integrated device complex.

[0042] In a particularly preferred embodiment, the plant complex comprises an electrolysis plant and a renewable energy plant, wherein a power source having an output is formed by the renewable energy plant, and wherein the electrolysis plant is connected to the output of the renewable energy plant.

[0043] This makes it possible to implement island grid operation in the plant complex, independent of the public grid, and to use electricity directly from renewable sources for electrolysis to form green hydrogen.

[0044] Preferably, the renewable energy plant in the plant complex comprises a wind energy plant.

[0045] In the device complex, the renewable energy device can also be a wind power device or a wind farm with a large number of wind power devices. In this case, the electrolysis device can also be supplied with AC power by multiple wind power devices connected together on the AC side. 100% renewable green electricity generated based on wind energy is particularly attractive in combination with electrolysis. The rectifier in the electrolysis device is connected to the input of the circuit device on the output side or is electrically connected to its input, and filtering and interference removal are achieved through the rectifier. Here, the rectifier converts the AC power from the wind power device into DC power, and at the same time, advantageously provides the DC voltage level required for operating the electrolyzer at the input. At the same time, a direct connection with the wind power device and an integrated device complex are achieved.

[0046] This also advantageously provides a possibility for filtering a plurality of electrolyzers connected electrically in parallel in an electrolysis system. In an electrolysis system, filtering can be performed centrally behind the rectifier once or directly at a plurality of electrolyzers connected in parallel using a plurality of smaller, appropriately designed filter mechanisms, which can then be switched on and off to vary the partial load. It is precisely when the electrolysis process in an electrolyzer is at a standstill that the electrolyzer is particularly susceptible to high-frequency stray currents caused by the operation of electrolyzers or sub-systems of the electrolysis system connected in parallel that the electrolyzer is particularly susceptible to high-frequency stray currents caused by the operation of electrolyzers or sub-systems of the electrolysis system.

[0047] In an alternative or additional embodiment of the plant complex, the electrolysis plant is preferably connected to a renewable energy plant, wherein the renewable energy plant has a photovoltaic plant, so that a DC power source with an output is formed, and wherein the electrolysis plant is connected to the output of the photovoltaic plant.

[0048] In an alternative embodiment, it is also possible and preferred that the renewable energy plant in the plant complex is a photovoltaic plant. During operation, a PV plant already provides direct current that can be easily used for electrolysis.

[0049] In the case of renewable energy plants, a combination of wind power plants and photovoltaic plants can also be present in a plant complex. For PV plants, no rectification is required, but wind power plants usually generate and provide alternating current in the first place. Therefore, a rectifier is required in a plant complex with a wind power plant for electrolysis purposes. The rectifier is preferably already a component of an electrolysis plant that is designed accordingly for operation at the wind power plant. However, the rectifier can also already be arranged in the wind power plant itself in order to provide direct current at the connection point or transfer point to the electrolysis plant.

[0050] For the design as a combined device, it is also possible to connect a battery or another energy storage device in parallel with the wind power device and / or the photovoltaic device in the device complex and integrate it into the device complex. The battery or energy storage device is then preferably also connected to a DC / DC converter, similar to the electrical connection of the photovoltaic device.

[0051] Therefore, direct connection of a battery or energy storage device can be provided, wherein preferably provision is then made for the battery or energy storage device to be supplied and charged by the power supply device. As a supplement to the renewable energy device (EE device), the battery or energy storage device is advantageously and very advantageously also used for load control and for evenly supplying the electrolysis device with the power of the battery and, in particular, as a buffer in windless and / or sunless weather conditions.

[0052] In the case of a photovoltaic system, it is preferably provided that the photovoltaic system has a DC regulator or a DC voltage converter which forms the output in the system complex.

[0053] In this case, the DC power supply of the photovoltaic system is formed at a predeterminable DC voltage level via the output of the DC regulator. The electrolysis system is directly and immediately connected to the output of the photovoltaic system. It is also conceivable and feasible that the DC regulator is a power electronic component of the electrolysis system and is adapted accordingly to the PV voltage level.

[0054] A DC voltage converter (also called a DC-DC converter) is a circuit that converts a DC voltage supplied at the input into a DC voltage with a higher, lower or inverted voltage level. The conversion is performed with the aid of a periodically working electronic switch and one or more energy storage devices. DC voltage converters are self-contained current converters. In the field of electrical energy technology, they are also called DC regulators. Inductors (inductor converters) for temporary energy storage consist of coils or converter transformers.

[0055] The advantages and advantageous embodiments of the electrolysis plant according to the invention are to be regarded as advantages and advantageous embodiments of the plant complex, and vice versa.

[0056] Further advantages, features and details of the invention are apparent from the following description of preferred exemplary embodiments and with the aid of the drawings. The features and feature combinations mentioned in the above description and the features and feature combinations mentioned below in the description of the figures and / or shown individually in the individual figures can be used not only in the respectively indicated combination but also in other combinations or alone without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Embodiments of the present invention are explained in more detail with reference to the accompanying drawings. Here, schematically and greatly simplified are:

[0058] Figure 1 A plant complex with an electrolysis plant and a wind energy plant having a direct DC coupling is shown;

[0059] Figure 2 Shown according to Figure 1 A device complex having an alternative filter circuit;

[0060] Figure 3 A device complex with an electrolytic device and a photovoltaic device having direct DC coupling is shown;

[0061] Figure 4 Shown according to Figure 3 A device complex having an alternative filter circuit.

[0062] The same reference numerals in the figures have the same meanings. DETAILED DESCRIPTION

[0063] Figure 1An equipment complex 100 according to the present invention is shown. The equipment complex 100 includes an electrolysis device 1 and a wind energy device 50A connected to the electrolysis device 1 as a renewable energy device (EE device) and a green power source. The electrolysis device 1 has an electrolysis cell 3 and a circuit device 5 electrically connected to the electrolysis cell 3. The circuit device 5 is connected to the electrolysis cell 3 via an output terminal 9. The circuit device also has an input terminal 7, via which direct current can be supplied to the electrolysis device. The input terminal 7 is designed to be connected to an external power supply, in particular an external direct current power supply. Direct current, i.e., so-called electrolysis direct current, is supplied from the direct current power supply via the circuit device 5. In order to supply high-quality direct current without interference and with noise suppression, the circuit device 5 has an electrical filter mechanism 11. The filter mechanism 11 is designed to be able to very effectively attenuate and suppress high-frequency signal components from the power supply. To this end, the filter mechanism 11 is designed as a low-pass section having an RC element as a passive element. Other possible solutions for designing the filter mechanism 11 are, for example, a second-order or higher-order low-pass section, which has an LRC-low-pass section, i.e., an inductor, an ohmic resistor, and a capacitor. Advantageously, the circuit device 5 can also be equipped with a filter mechanism 11 designed as an active filter. The filter mechanism 11 then has, for example, an operational amplifier as an active element. The problem of ground links and the corresponding unfavorable input of high-frequency interference signals into the electrolysis device 1 is greatly reduced by the filter mechanism 11. This protects particularly sensitive components of the electrolysis cell 3, in particular a large number of electrolytic cells, and ensures a highly stable and high-quality target voltage.

[0064] The electrolysis device 1 also has a rectifier 15, which is connected on the output side to the input 7 of the circuit arrangement 5. On the input side, the rectifier 15 is connected to an AC power source, in this embodiment to a wind energy device 50A that supplies AC power. A direct AC connection (AC connection) is made via the output 52 of the wind energy device 50A. By means of the electrical filter device 11 in the circuit arrangement 5, a direct current that is largely free of high-frequency signal components can be supplied to the electrolysis cell 3 via the filter device 11 in the case of a direct connection.

[0065] The circuit arrangement 5 is supplied with direct current via a rectifier 15, which in turn enables very effective filtering by a filter mechanism for direct DC connection. Direct current, ie electrolysis current, is thus supplied to the electrolyzer 3. The electrolyzer 3 can be designed as a PEM electrolyzer or an alkaline electrolyzer.

[0066] In order to supply direct current for the electrolysis process, the electrolysis device 1 is directly connected to the wind energy device 50A. First, it is connected to the rectifier 15 via the output terminal 52 of the wind energy device 50A, and then Figure 1, connected in a series circuit to a circuit arrangement 5 with a filter mechanism 11, which in turn supplies electrolytic direct current to the electrolyzer 3 via an output 9. The wind energy installation 50A initially generates alternating current in a generator. In order to be able to transmit the direct current to the electrolyzer 3, a rectifier 15 is provided in the electrolyzer 1, so that a direct connection is made via this rectifier 15 at the output 52 on the AC side, wherein the rectifier here is advantageously a power element of the electrolyzer 1. However, rectification can also be carried out at the wind energy installation 50A itself before transmission.

[0067] In order to change the voltage or current intensity for electrolysis, the rectifier 15 is controllable and is designed as a three-phase rectifier, such as a B6 bridge rectifier. The rectifier has an IGBT, i.e. an insulated gate bipolar transistor (Insulated-Gate-Bipolar-Transistor), as a semiconductor element, which is not shown in detail. This is a frequently used element in power electronics because it combines the advantages of bipolar transistors (such as good conduction properties, high cut-off voltage, robustness) and the advantages of field effect transistors (almost power-free control). The significant advantages of IGBTs are high voltage limits and high current limits: voltages up to 6500V and currents up to 3600A and powers up to several megawatts, which makes IGBTs very suitable for electrolysis equipment. As a result, the IGBTs in the rectifier 15 can be used ideally for the working range of the electrolyzer 3.

[0068] Depending on the application, it is also conceivable to use so-called IGCTs, i.e. integrated gate-commutated thyristors, in the rectifier 15. This reduces the wiring effort, increases the maximum pulse frequency for control and improves the switching times in the case of series connection, which is advantageous. An area of ​​application for IGCTs is high-performance current converters. Individual modules typically switch currents of several thousand amperes at a typical cut-off voltage of 4500 V.

[0069] With the circuit arrangement 5, very effective interference removal is achieved through the filter mechanism 11. As a result, high-frequency stray currents are greatly reduced during operation, which can be input through the ground loop and damage the electrolyzer 3 with a very sensitive electrolytic cell, because the ohmic loss through the ground loop can cause a very unfavorable voltage drop on the electrolytic cell. The lower the resistance of the ground connection between the components involved, the smaller the potential difference. This is usually achieved by cables and plug connectors with low resistance, large shielding cross-section, low contact transition resistance, and by current decoupling that may be selectively additionally specified according to the design. A transformer, that is, an iron core with a coil, can also be simply included in the filter mechanism 11, which is another measure for interference removal and filtering, so as to reduce stray currents to the ground in particular as a whole.

[0070] Therefore, the desired filtering effect can also be achieved in the filter mechanism 11 by utilizing the inductance, and the filter mechanism 11 can be designed and adjusted accordingly. Here, for example, a plurality of passive filters or a mixed passive and active filter device for different frequencies can also be provided for the filter mechanism 11 in the filter mechanism 11 of the electrolysis device 1. In addition, this can also be accomplished by using a series of coils / lines with high inductance, RC elements (low-pass filters), second-order LRC low-pass sections, using a higher-order low-pass section or an active filter.

[0071] During the operation of the plant complex 100, green power is generated in the wind power plant 50A. The alternating current generated in the generator is converted into direct current in the rectifier 15. Thus, the renewable energy plant 50 (taking the wind power plant 50A as an example) ultimately provides a direct current power supply, so that the direct current is directly fed into the input end 7 of the electrolysis device 1 via the output end of the rectifier 15 and first transmitted to the circuit arrangement 5. In the circuit arrangement 5, filtering is performed by the filter mechanism 11, so that stray currents are suppressed or avoided.

[0072] By means of the circuit arrangement 5, a non-interfering or noise-free electrolysis DC voltage is provided on the output side at the output 9, with which the electrolysis cell 3 is operated stably, water being decomposed into hydrogen and oxygen. Ground loops are avoided. The advantageous direct DC connection of the electrolysis system 1 to the wind energy system 52A makes island operation independent of the grid possible and allows the generation of green electricity in a decentralized manner onshore or offshore, depending on the application. The proportion of green hydrogen is 100% here.

[0073] In a further embodiment of a plant complex 100 according to the invention having a wind energy plant 50A, Figure 2 An alternative filter circuit is shown. In this case, the series connection of the circuit arrangement 5 and the filter means 11 is not provided, but the filter function is implemented by connecting the circuit arrangement 5 directly to the output side of the rectifier 15 and leading it to the reference potential 17, in particular to ground potential, zero potential or ground. The electrolyzer 3 is thus supplied with a high-quality, filtered and interference-free DC voltage via the output 9. The operation of the filtered direct connection of the electrolysis device 1 to the wind energy device 50A provided by the circuit arrangement 5 is similar to that of Figure 1 The device complex 100 described in .

[0074] Figure 3A plant complex 100 with a directly DC-coupled electrolysis plant 1 and a photovoltaic plant 50B is shown, which is a very advantageous plant concept with a DC power supply for supplying direct current to the electrolysis plant 1. In this case, the renewable energy plant 50 has a photovoltaic plant 50B with a large number of PV modules, which are not shown in detail. The photovoltaic plant 50B can be designed, for example, as a large-area and high-power open-field plant—preferably in a sunny area, so that a PV power with a peak value of at least 5 MW of power can be used for electrolysis. Figure 1 A similar system concept and corresponding system components, namely with a circuit arrangement 5 and an electrolysis cell 3 , wherein the circuit arrangement 5 is arranged in series between the photovoltaic system 50B and the electrolysis cell 3 . In this case, the filter device 11 is accordingly integrated in the series circuit and connected upstream of the electrolysis cell 3 .

[0075] In order to obtain a desired and advantageous voltage level for connection to the electrolysis device 1, Figure 3 In the example of , a DC regulator 19 is connected to the photovoltaic device 50B. The DC regulator 19 is also called a DC-DC converter, so that the DC voltage supplied from the photovoltaic device 50B to the input terminal of the DC regulator is converted into a DC voltage with a higher, lower or reverse voltage level. The conversion is performed with the help of an electronic switch and one or more energy storage devices that work periodically. The DC regulator 19 is also called a DC voltage converter, which is a self-propelled current converter that plays an important role in the field of electric energy technology. The inductor (inductive converter) used to temporarily store energy is composed of a coil or a converter transformer.

[0076] The DC regulator 19 connected to the photovoltaic device 50B is connected to the input 7 of the circuit arrangement 5 on the output side at the output 52, thereby realizing a direct connection with the electrolysis device 1 and supplying PV direct current, wherein stray currents are effectively suppressed by the filter means 11, in particular a low-pass filter. In this case, a DC power supply at a predeterminable DC voltage level is formed for the photovoltaic device 52B via the output 52 of the DC regulator. The electrolysis device 1 is directly and immediately connected to the output 52 of the photovoltaic device. It is also conceivable and possible that the DC regulator 19 is a power electronic component of the electrolysis device 1 itself and is adjusted and preconfigured accordingly for the PV voltage level.

[0077] In a further embodiment of a plant complex 100 according to the invention having a photovoltaic plant 52B, Figure 4An alternative filter circuit is shown in FIG. Here, the series connection of the circuit device 5 and the filter mechanism 11 is not provided, but the connection and guarantee of the filter function are achieved by connecting the circuit device 5 directly to the DC regulator 19 on the output side and guiding it to the reference potential 17, in particular the ground potential, the zero potential or the ground. As a result, a high-quality DC voltage that has been filtered and interference-free is supplied to the electrolyzer 3 via the output terminal 9. The working method of directly connecting the electrolysis device 1 to the photovoltaic device 50B without interference provided by the circuit device 5 and via the filter mechanism 11 is similar to Figure 3 The device complex 100 described in .

[0078] The invention proposes an electrolysis plant 1, by means of which direct current or alternating current from renewable energy sources can be fed directly and without interference into the electrolysis plant 1, so that 100% green hydrogen can be produced in the electrolysis process. This is particularly advantageously done in the described plant complex 100 comprising the electrolysis plant 1 and the renewable energy plant 50, which are directly electrically connected to one another and are arranged in close spatial proximity and are advantageously integrated into the plant complex 100.

[0079] Here, the circuit arrangement 5 with the filter mechanism 11 realizes a particularly simple and effective direct DC connection. Compared with the alternative solution with a transformer that can use the principle of galvanic isolation or galvanic decoupling, this seems to have a cost advantage. Even in the case where a complex and expensive transformer system cannot be provided or cannot be used due to local equipment technical conditions and restrictions, it is also preferred to filter on the DC side using an electrical filter mechanism 11 according to the present invention, wherein the high-frequency signal component is attenuated. In addition, this can also be done by using a coil / line with a high inductance in series, an RC element (low-pass filter), a second-order LRC low-pass section, using a higher-order low-pass section or an active filter. Here, the filtering in the circuit arrangement 5 with the filter mechanism 11 is either performed directly at the rectifier 15 or between the rectifier 15 and the electrolyzer 3. It is also possible to filter at the grounding line, for example in the star point grounding in the generator system or at the rectifier 15 or in the rectifier 15. The filtering can also be carried out at a specified ground connection in the electrolysis system, for example in the middle of a module row, where the potential is already close to the reference potential 17 or ground potential.

[0080] The electrolysis plant 1 according to the invention is particularly advantageously used both for PEM hydrogen electrolysis plants and for alkaline electrolysis plants in a plant complex 100 with a renewable energy plant 50. The problem of suppressing high-frequency ground currents in the case of direct connections, in particular DC direct connections, has been recognized and solved very advantageously.

Claims

1. An electrolysis device (1), comprising an electrolysis cell (3) and a circuit arrangement (5), the circuit arrangement having an input terminal (7) for connection to a power supply and an output terminal (9) connected to the electrolysis cell (3), wherein: The circuit arrangement (5) has an electrical filter device (11) which is designed to attenuate high-frequency signal components, in particular from the power supply.

2. The electrolysis device (1) according to claim 1, wherein: The filter mechanism (11) has a low-pass portion.

3. The electrolysis device (1) according to claim 1 or 2, wherein: The filter mechanism (11) is designed as a first-order low-pass section having an RC element.

4. The electrolysis device (1) according to any one of the preceding claims, wherein: The filter mechanism (11) has an inductance for attenuating the high-frequency component.

5. The electrolysis apparatus (1) according to any one of the preceding claims, wherein: The filter mechanism (11) is designed as a second-order or higher-order low-pass section having at least one LRC low-pass section.

6. The electrolysis device (1) according to claim 1, comprising a filter arrangement (11) designed as an active filter, the filter arrangement comprising an operational amplifier.

7. An electrolysis device (1) according to any one of the preceding claims, comprising a rectifier (15), which is connected to the input end (7) of the circuit device (5) on the output side and can be connected to an external AC power supply on the input side, so that direct current without high-frequency signal components can be supplied to the electrolytic cell (3) via the filter mechanism (11).

8. The electrolysis device (1) according to claim 7, wherein: The rectifier (15) is controllable and / or is designed as a three-phase rectifier, in particular as a B6 bridge rectifier.

9. The electrolysis device (1) according to claim 7 or 8, wherein: The filter mechanism (11) is connected in series between the rectifier (15) and the electrolytic cell (3).

10. The electrolysis device (1) according to any one of claims 7, 8 or 9, wherein: The filter device (11) is connected to the rectifier (15) and to a reference potential (17), in particular to ground.

11. A plant complex (100) comprising an electrolysis plant (1) according to any one of the preceding claims and comprising a renewable energy plant (50), wherein: A power source having an output (52) is formed by the renewable energy device (50), and the electrolysis device (1) is connected to the output (52) of the renewable energy device (50).

12. The device complex (100) according to claim 11, wherein: The renewable energy plant (50) has a wind energy plant (50A).

13. A plant complex (100) comprising an electrolysis plant (1) according to any one of claims 1 to 6 and a renewable energy plant (50), wherein: The renewable energy device (50) has a photovoltaic device (50B), thereby forming a DC power supply with an output terminal, and wherein the electrolysis device (1) is connected to the output terminal (52) of the photovoltaic device (50B).

14. The device complex (100) according to claim 13, wherein: The photovoltaic device (50B) has a DC regulator (19) forming the output end (52).

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