Device for supplying electrolysis unit with direct current
By using a combination device of multiple secondary winding transformers and multiple rectifier units, DC current supply is provided to the electrolytic unit, which solves the problem of inflexible DC current supply of the electrolytic unit in the prior art, and achieves flexible matching and expansion, and improves the scalability of the system.
Patent Information
- Application Number
- CN202280100249.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-21
- Publication Date
- 2025-04-18
AI Technical Summary
The prior art has difficulty providing a wide range of DC current supply devices and methods for electrolytic units, especially when the electrolytic equipment is required, where flexible and scalable solutions are lacking.
Using a combination device of multiple secondary winding transformers and multiple rectifier units, through the modular design of the transformer's multiple secondary windings and rectifier units, each electrolytic unit string provides independent DC current supply, achieving flexible matching and expansion.
It realizes flexible DC current supply to the electrolytic cell string, supports different number of electrolytic cell strings, reduces the complexity of the extended electrolytic equipment, and improves the scalability and flexibility of the system.
Smart Images
Figure CN119856379A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a device and a method for supplying an electrolysis cell with direct current. Background Art
[0002] Electrolysis equipment usually has a plurality of electrolysis cells, with which, for example, hydrogen and oxygen can be obtained from water. Here, the electrolysis cells are connected to form a plurality of series circuits, wherein each series circuit forms an electrolysis cell string. Summary of the invention
[0003] The object of the present invention is to specify a device and a method for supplying an electrolysis cell with direct current which can be used universally.
[0004] According to the invention, the above-mentioned object is achieved by a device and a method according to the independent claims. Advantageous embodiments of the device and the method are given in the dependent claims.
[0005] A device for supplying electrolysis cells with direct current is disclosed, wherein the electrolysis cells are arranged in a plurality of electrolysis cell strings and each electrolysis cell string has a series (electrical) connection (or series circuit) of a plurality of electrolysis cells, wherein:
[0006] - the device comprises a transformer having a primary winding and a plurality of secondary windings (in particular electrically insulated with respect to one another),
[0007] - the device has a plurality of rectifier units, wherein each secondary winding is electrically connected to the input of one of the rectifier units, and
[0008] - The output of the rectifier unit is in turn electrically connected to one of the electrolysis cell strings.
[0009] Such a direct current supply device is advantageously widely usable, since a (particularly own) secondary winding and a own rectifier unit are provided for each electrolysis cell string. In other words, it is a modular device for direct current supply. As a result, the device for direct current supply can be easily adapted to a different number of electrolysis cell strings, in particular when expanding an existing electrolysis plant with further electrolysis cell strings. In other words, the device has good scalability.
[0010] The device can be designed as follows:
[0011] - The secondary windings are galvanically isolated from each other. This enables a simple modular construction even for a different number of electrolysis cell strings.
[0012] The device can be designed as follows:
[0013] - Each secondary winding is associated with a (in particular its own) rectifier unit. This means that the number of rectifier units is at least as large as the number of secondary windings. This also enables a modular design of the device for supplying direct current.
[0014] The device can be designed as follows:
[0015] - The transformer has at least 4, in particular at least 10 secondary windings. The transformer is in particular a multi-secondary winding transformer. As a result, the transformer can also be used to supply electrical energy (here: DC voltage and DC current) to a larger number of electrolysis cell strings.
[0016] The device can be designed as follows:
[0017] - The secondary windings each have a secondary voltage of substantially the same amplitude. That is, the secondary windings can be designed in such a way that they each provide a secondary voltage of substantially the same amplitude. This simplifies the practical realization of the device.
[0018] The device can be designed as follows:
[0019] - Each of the secondary windings has a different phase shift relative to the primary winding. In other words, all secondary windings have different phases. That is, the phase shifts or phases of all secondary windings are different from one another. As a result, relatively small grid disturbances occur during operation of the device, in particular relatively few harmonics are generated. As a result, no or only few compensation measures (such as filters for filtering out harmonics) are required.
[0020] The device can be designed as follows:
[0021] - The rectifier unit has respectively uncontrollable or controllable power semiconductor elements, in particular diodes, thyristors, IGBTs or MOSFETs. In this case, the rectifier unit can be designed as a line-commutated rectifier unit, in which case the rectifier unit has in particular diodes or thyristors. However, the rectifier unit can also be designed as a self-commutated rectifier unit, in which case the rectifier unit has in particular IGBTs or MOSFETs. In this way, the rectifier unit can be adapted to different requirements.
[0022] The device can be designed as follows:
[0023] - The power semiconductor elements are power semiconductor elements based on silicon carbide (SiC) or gallium nitride (GaN). This allows relatively cost-effective rectifier units to be realized which have only low electrical losses.
[0024] The device can be designed as follows:
[0025] - A step-up converter or a step-down converter is connected between the output end of at least one of the rectifier units, in particular all of the rectifier units, and the corresponding electrolytic cell string. As a result, the DC voltage applied to the electrolytic cell string can be further varied within a wider range, so that the DC voltage applied to the electrolytic cell string can be adapted to different conditions.
[0026] The device can be designed as follows:
[0027] - An isolating switch and / or grounding switch is arranged between at least one of the secondary windings, in particular all of the secondary windings, and the respective input of the rectifier unit. In particular, a combined isolating-grounding device can be arranged. This simplifies, for example, the maintenance of a non-operating electrolysis cell string.
[0028] The device can be designed as follows:
[0029] - The outputs of a plurality of rectifier units are connected in parallel, and the outputs of the parallel connection (of these rectifier units) are connected to a string of electrolysis units. As a result, a larger DC current can be provided to the electrolysis units by means of uniform / similar rectifier units. In this case, the inputs of the rectifier units can be connected to their own secondary windings accordingly. Alternatively, the inputs of the rectifier units can be connected to a common secondary winding. In the latter case, in particular, decoupling elements, such as choke coils, can be provided in order to weaken the compensation processes between the rectifier units.
[0030] The device can be designed as follows:
[0031] - The output ends of the plurality of rectifier units are connected to form a series circuit, and the series circuit is connected to the electrolysis cell string. More precisely, the series circuit at the output end is electrically connected in series with the electrolysis cell string. Thus, a larger DC voltage can be provided to the corresponding electrolysis cell string through a uniform / similar rectifier unit.
[0032] Furthermore, an electrolysis device is disclosed, which has a device for supplying direct current according to one of the above-mentioned variants. The electrolysis device has a plurality of electrolysis cells, wherein the electrolysis cells are arranged in a plurality of electrolysis cell strings, and each electrolysis cell string has a series (electrical) connection (or series circuit) of a plurality of electrolysis cells. Each electrolysis cell string is electrically connected to the output of one of the rectifier cells.
[0033] A method for supplying electrolysis cells with direct current using a transformer and a plurality of rectifier units is also disclosed, wherein the electrolysis cells are arranged in a plurality of electrolysis cell strings, and each electrolysis cell string has a series circuit of a plurality of electrolysis cells, wherein:
[0034] - a transformer having a primary winding and a plurality of secondary windings (electrically isolated from each other), and
[0035] - Each secondary winding is electrically connected to an input of one of the rectifier units, wherein, in the method,
[0036] - A respective one of the electrolysis cell strings is supplied with direct current by a respective output of one of the rectifier cells.
[0037] The method may be run such that
[0038] - The secondary windings accordingly provide a secondary voltage of substantially the same amplitude.
[0039] The device, the electrolysis apparatus and the method have the same or similar properties and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The present invention will be described in more detail below with the aid of an embodiment. Here, the same reference numerals indicate the same or identically functioning elements. For this purpose, in the accompanying drawings:
[0041] Figure 1 shows an embodiment of an electrolysis apparatus,
[0042] Figure 2 An embodiment of a part of an electrolysis device is shown, in which the outputs of two rectifier units are connected in series.
[0043] Figure 3 An embodiment of a part of an electrolysis apparatus is shown, in which the outputs of two rectifier units are connected in parallel, and
[0044] Figure 4 A further embodiment of a part of an electrolysis device is shown, in which the outputs of two rectifier units are connected in parallel. DETAILED DESCRIPTION
[0045] Figure 1 An embodiment of an electrolysis device 1 is shown. The electrolysis device 1 has a device 3 for supplying direct current to electrolysis cells and m electrolysis cell strings 5. Here, a first electrolysis cell string 5_1, a second electrolysis cell string 5_2 and an m-th electrolysis cell string 5_m are shown. Each electrolysis cell string 5 has a series circuit of a plurality of electrolysis cells; in this embodiment, n electrolysis cells 7_1 to 7_n are respectively electrically connected in series and respectively form a series circuit.
[0046] The device 3 for supplying direct current has a transformer 9 having a transformer core 12, a primary winding 15 and m secondary windings 18_1 to 18_m. The m secondary windings 18_1 to 18_m are electrically insulated from one another. The m secondary windings 18_1 to 18_m are galvanically isolated from one another.
[0047] Generally speaking, the transformer has m secondary windings. For example, the transformer can have at least 4 secondary windings, preferably at least 10 secondary windings. However, the transformer 9 can also have significantly more secondary windings, for example at least 20, at least 50 or at least 100 secondary windings. The transformer is a multi-secondary winding transformer.
[0048] The m secondary windings 18_1 to 18_m have substantially the same amplitude of the secondary voltage. Each of the secondary windings 18_1 to 18_m has a different phase shift relative to the primary winding. As a result, only a small number of harmonics are generated and only small grid disturbances occur. As a result, no or only a small number of compensation measures (such as filters) are required, which brings cost advantages.
[0049] Each secondary winding 18 of the transformer is associated with a (own) rectifier unit 22. Each rectifier unit 22 has an input 25 and an output 28. Thus, for example, the first secondary winding 18_1 is electrically connected to the input 25_1 of the first rectifier unit 22_1; that is, the first secondary winding 18_1 is associated with the first rectifier unit 22_1. The second secondary winding 18_2 is electrically connected to the input 25_2 of the second rectifier unit 22_2, etc. That is, the number of rectifier units 22 is at least as large as the number of secondary windings 18.
[0050] An isolating switch and / or grounding switch 24_1 (in particular in the form of an isolating-grounding combination device 24_1) is connected between the first secondary winding 18_1 and the input 25_1 of the first rectifier unit 22_1. The isolating switch and / or grounding switch 24_1 is optional and can also be omitted. The isolating switch and / or grounding switch 24_1 makes it possible to switch the first rectifier unit 22_1 and the first electrolysis cell string 5_1 to no current and / or to ground the first rectifier unit 22_1 and the first electrolysis cell string 5_1 when necessary (for example when performing maintenance or repair).
[0051] The output terminal 28_1 of the first rectifier unit 22_1 is provided with a capacitor 31_1 for smoothing the DC voltage. The output terminal 28_1 of the first rectifier unit 22_1 is electrically connected to the first electrolytic cell string 5_1. The first rectifier unit 22_1 supplies DC current to the first electrolytic cell string 5_1 (and thus to the electrolytic cells 7_1 to 7_n contained in the string).
[0052] A boost converter 34_1 or a buck converter 34_1 is connected between the output end 28_1 of the first rectifier unit 22_1 and the first electrolysis cell string 5_1. The boost converter 34_1 or the buck converter 34_1 is optional and can be omitted. The boost converter 34_1 or the buck converter 34_1 enables the DC voltage applied to the electrolysis cell string 5_1 to be increased or decreased.
[0053] The first rectifier unit 22_1 has an uncontrollable power semiconductor element (e.g. a diode) or a controllable power semiconductor element (e.g. a thyristor, an IGBT or a MOSFET). In this case, the first rectifier unit 22_1 can form a line-commutated rectifier (which then in particular has a diode or a thyristor). However, the first rectifier unit 22_1 can also form a self-commutated rectifier, which then in particular has an IGBT or a MOSFET. As power semiconductor elements, power semiconductor elements based on silicon carbide (SiC) or gallium nitride (GaN) can be used. However, as power semiconductor elements, other power semiconductor elements, such as power semiconductor elements based on silicon (Si), can also be used.
[0054] The following uses the first electrolytic cell string 5_1 as an example to explain the process of supplying direct current to the electrolytic cells. In a similar manner, direct current is supplied to the other electrolytic cell strings 5_2 to 5_m.
[0055] The primary winding 15 of the transformer 9 is connected to an AC energy supply network (not shown), for example a medium voltage AC energy supply network. The transformer 9 transforms the AC voltage of the medium voltage AC energy supply network into a low voltage (for example into 1 kV); an AC current having this lower voltage is output at the first secondary winding 18_1. The isolating switch 24_1 is closed; the grounding switch is open. This AC current is conducted to the input 25_1 of the first rectifier unit 22_1. The first rectifier unit 22_1 rectifies the AC current provided by the first secondary winding 18_1 and outputs a DC current at the output 28_1. This DC current is optionally smoothed by a smoothing capacitor 31_1. This DC current now flows through a step-up converter or a step-down converter 34_1 (wherein the voltage can optionally be increased or decreased), flows to the first electrolysis cell string 5_1, and supplies the electrolysis cells 7_1 to 7_n contained in this string 5_1 with electrical energy.
[0056] according to Figure 1 The electrolysis device may be configured as three-phase, that is, the first secondary winding 18_1, the first rectifier unit 22_1, the first electrolysis unit string 5_1, etc. may be configured as three-phase.
[0057] Figure 2 An embodiment of an electrolysis device is shown, in which the first output terminal 28_1 of the first rectifier unit 22_1 and the second output terminal 28_2 of the second rectifier unit 22_2 are electrically connected in series, thereby forming a series circuit. This series circuit of the two output terminals 28_1 and 28_2 is connected to the first electrolysis cell string 5_1. Through this series circuit, the output voltages of the first rectifier unit 22_1 and the second rectifier unit 22_2 are added, so that a larger DC voltage is applied to the first electrolysis cell string 5_1. As a result, according to Figure 1 Compared to the embodiment of the present invention, a larger DC current flows through the electrolysis cells 7_1 to 7_n. This makes it possible to provide a DC voltage of different magnitudes for the electrolysis cell string using a unified rectifier unit when necessary. In this embodiment and the following embodiments, the optional isolating switch, grounding switch, boost converter and / or buck converter are omitted, but the optional isolating switch, grounding switch, boost converter and / or buck converter may also be used.
[0058] Figure 3 and Figure 4 Accordingly, an embodiment is shown in which the first output terminal 28_1 of the first rectifier unit 22_1 and the second output terminal 28_2 of the second rectifier unit 22_2 are electrically connected in parallel, and the parallel-connected output terminals 28_1 and 28_2 are connected to the first electrolysis cell string 5_1. By connecting the output terminals of the rectifier units in parallel, the output DC currents of the first rectifier unit 22_1 and the second rectifier unit 22_2 are added together, thereby applying a larger DC current to the first electrolysis cell string 5_1. Thus, according to Figure 1 Compared to the embodiment of FIG. 1 , a larger direct current flows through the electrolysis cells 7_1 to 7_n. Figure 3 and Figure 4 The embodiments of the present invention differ only in the connection method of the input terminals of the rectifier unit.
[0059] exist Figure 3 In the embodiment of the present invention, the input terminals of the rectifier units are respectively connected to their own secondary windings. Therefore, the first input terminal 25_1 of the first rectifier unit 22_1 is electrically connected to the first secondary winding 18_1; that is, the first rectifier unit 22_1 is supplied with AC current only by the first secondary winding 18_1. The second input terminal 25_2 of the second rectifier unit 22_2 is electrically connected to the second secondary winding 18_2; that is, the second rectifier unit 22_2 is supplied with AC current only by the second secondary winding 18_2.
[0060] In contrast, Figure 4In the embodiment of the present invention, the input terminals of the rectifier units are connected to a common secondary winding. Therefore, the first input terminal 25_1 of the first rectifier unit 22_1 is electrically connected to the first secondary winding 18_1; the second input terminal 25_2 of the second rectifier unit 22_2 is also electrically connected to the first secondary winding 18_1. In other words, both the first rectifier unit 22_1 and the second rectifier unit 22_2 are (only) supplied with AC current by the first secondary winding 18_1. Here, an electrical decoupling element (here: choke coil) 403 is arranged at the input terminal of the rectifier unit in order to limit the size of the compensation current that may flow between the rectifier units 22_1 and 22_2.
[0061] A device for supplying an electrolysis cell with direct current, a method for supplying an electrolysis cell with direct current, and an electrolysis system are described which can be used universally and can be easily adapted to different requirements with regard to the direct current to be provided and / or the direct voltage to be provided.
[0062] In this case, a multi-secondary winding transformer with a plurality of insulated secondary windings is used. These secondary windings have a different phase shift relative to the primary winding. This makes it possible to achieve grid-friendly properties, so that relatively fewer harmonics occur, and therefore no or significantly fewer filters are required. A plurality of similar rectifier units enables a modular design of the device. The device for supplying direct current can also be referred to as a "multi-rectifier".
[0063] When using self-commutated rectifier units (which can also be operated with higher pulses), a desired power factor (cosine of the phase shift angle φ between current and voltage) can be set for the supplying AC network, which in turn can make previously required compensation devices superfluous.
[0064] The device described for supplying direct current can be used flexibly and has a finely graded and redundant structure. For example, even if individual rectifier units fail, operation can continue, if necessary with slightly lower power and less grid disturbances.
[0065] Due to the large number of rectifier units, each rectifier unit can be operated at a correspondingly lower voltage. As a result, the rectifier units can be manufactured at low cost. For example, low-cost power semiconductor components can be used, in particular power semiconductor components based on silicon carbide (SiC) or gallium nitride (GaN). If the voltage of each rectifier unit is, for example, not much higher than 600 V, power semiconductor components based on gallium nitride can be advantageously used.
[0066] The flexibility of the possibilities for use of the device can be further additionally increased if a series or parallel connection of rectifier cells, or more precisely a series or parallel connection of the outputs of the rectifier cells, is used.
[0067] For example, the device and the method can be used in proton exchange membrane (PEM) electrolysis plants, but also in other electrolysis plants. In this case, the individual electrolysis cells can be operated at a voltage of about 2 V, for example. In the case of a large number of electrolysis cells connected in series in an electrolysis cell string, each string generates, for example, a DC voltage of up to 1 kV and a DC current of up to several kA. The described device enables a powerful and adjustable DC current supply for such an electrolysis plant.
[0068] List of reference numerals:
[0069] 1Electrolysis equipment
[0070] 3Device for supplying direct current
[0071] 5 electrolysis unit string
[0072] 7 Electrolysis Unit
[0073] 9 Transformer
[0074] 12 Transformer core
[0075] 15 Primary Winding
[0076] 18 Secondary Winding
[0077] 22 rectifier units
[0078] 24Isolating switches, earthing switches, and combined isolating-earthing devices
[0079] 25 Input of the rectifier unit
[0080] 28 Output of the rectifier unit
[0081] 31 Capacitor
[0082] 34Boost converter, buck converter
[0083] 403 Decoupling components, choke coils
Claims
1. A device (1) for supplying a direct current to an electrolysis cell, wherein: The electrolysis cells (7_1 ... 7_n) are arranged in a plurality of electrolysis cell strings (5_1 ... 5_m), and each electrolysis cell string (5_1 ... 5_m) has a series connection of a plurality of electrolysis cells (7_1 to 7_n), wherein: - the device comprises a transformer (9) having a primary winding (15) and a plurality of secondary windings (18_1 . . . 18_m), - the device comprises a plurality of rectifier units (22_1 ... 22_m), wherein each secondary winding (18_1 ... 18_m) is electrically connected to an input (25_1 ... 25_m) of one of the rectifier units (22_1 ... 22_m), and The outputs (28_1 ... 28_m) of the rectifier units (22_1 ... 22_m) are each electrically connected to one of the electrolysis cell strings (5_1 ... 5_m).
2. The device according to claim 1, It is characterized in that The secondary windings (18_1 ... 18_m) are galvanically isolated from one another.
3. The device according to claim 1 or 2, It is characterized in that - Each secondary winding (18_1 ... 18_m) is associated with a rectifier unit (22_1 ... 22_m).
4. The device according to any one of the preceding claims, It is characterized in that The transformer has at least 4, in particular at least 10, secondary windings (18_1 . . . 18_m).
5. The device according to any one of the preceding claims, It is characterized in that The secondary windings ( 18_1 . . . 18_m) each have a secondary voltage of substantially the same amplitude.
6. The device according to any one of the preceding claims, It is characterized in that - Each of the secondary windings (18_1 . . . 18_m) has a different phase shift relative to the primary winding (15).
7. The device according to any one of the preceding claims, It is characterized in that The rectifier units ( 22_1 . . . 22_m) each have uncontrollable or controllable power semiconductor elements, in particular diodes, thyristors, IGBTs or MOSFETs.
8. The device according to claim 7, It is characterized in that - The power semiconductor element is a power semiconductor element based on silicon carbide or gallium nitride.
9. The device according to any one of the preceding claims, It is characterized in that A step-up or step-down converter (34_1 ... 34_m) is connected between the output (28_1 ... 28_m) of at least one of the rectifier cells (22_1 ... 22_m), in particular all of the rectifier cells, and the corresponding electrolysis cell string (5_1 ... 5m).
10. The device according to any one of the preceding claims, It is characterized in that - a disconnecting switch and / or a grounding switch (24_1 ... 24_m) is arranged between at least one of the secondary windings (18_1 ... 18_m), in particular all of the secondary windings, and the respective input (25_1 ... 25_m) of the rectifier unit (22_1 ... 22_m).
11. The device according to any one of the preceding claims, It is characterized in that - Output terminals (28_1, 28_2) of a plurality of rectifier units (22_1, 22_2) are connected in parallel, and the output terminals (28_1, 28_2) connected in parallel are connected to an electrolysis unit string (5_1).
12. The device according to any one of the preceding claims, It is characterized in that - The output terminals (28_1, 28_2) of a plurality of rectifier units (22_1, 22_2) are connected to form a series circuit, and the series circuit is connected to an electrolysis unit string (5_1).
13. An electrolysis device (1) comprising a device (3) for supplying direct current according to any one of claims 1 to 12 and comprising a plurality of electrolysis cells (7_1 to 7_n), wherein: The electrolysis cells (7_1 to 7_n) are arranged in a plurality of electrolysis cell strings (5_1 ... 5_m), and each electrolysis cell string (5_1 ... 5_m) has a series circuit of a plurality of electrolysis cells (7_1 to 7_n), and each electrolysis cell string (5_1 ... 5_m) is electrically connected to an output terminal of one of the rectifier cells (22_1 ... 22_m).
14. A method for supplying a direct current to an electrolysis cell using a transformer (9) and a plurality of rectifier units (22_1 ... 22_m), wherein: The electrolysis cells (7_1 to 7_n) are arranged in a plurality of electrolysis cell strings (5_1 ... 5_m), and each electrolysis cell string (5_1 ... 5_m) has a series connection of a plurality of electrolysis cells (7_1 to 7_n), wherein: - the transformer (9) has a primary winding (15) and a plurality of secondary windings (18_1 ... 18_m), and - each secondary winding (18_1 ... 18_m) is electrically connected to an input (25_1 ... 25_m) of one of the rectifier units (22_1 ... 22_m), wherein in the method, A respective one of the electrolysis cell strings (5_1 ... 5_m) is supplied with direct current by a respective output (28_1 ... 28_m) of one of the rectifier cells (22_1 ... 22_m).
15. The method according to claim 14, It is characterized in that The secondary windings ( 18_1 . . . 18_m) each provide a secondary voltage of substantially the same amplitude.