Circuit arrangement, electrolysis device, and method for operating a circuit arrangement or an electrolysis device

Abstract

A circuit arrangement including at least one coil device (1) having a first coil (2) and a second coil (3), wherein the first coil (2) is connected to the DC voltage side of a rectifier (8) of the circuit arrangement (7), the second coil (3) is connected to a current source (12) of the circuit arrangement (7), and the first coil (2) and the second coil (3) are coupled to each other via coupling parts (4) of the coil device (1) that form the cores of both coils (2, 3).

Description

[Technical field]

[0001] The present invention relates to a circuit arrangement including at least one coil arrangement having a first coil and a second coil, the first coil being connected to a DC voltage side of a rectifier of the circuit arrangement and the second coil being connected to a current source of the circuit arrangement.Furthermore, the present invention relates to an electrolysis device as well as a method for operating the circuit arrangement or the electrolysis device. [Background technology]

[0002] Chemical electrolysis, such as hydrogen electrolysis, is carried out with electrolysers operating on direct current. In the case of electrolysis carried out on an industrial scale, the direct current is supplied, for example, via a separately excited rectifier. This rectification of the grid-side AC voltage leads to the generation of harmonics depending on the operating mode of the rectifier, which may put a strain on the AC and / or DC grid. One possibility to reduce this strain can be achieved, for example, by a high pulse rate system, in which several rectifiers are operated out of phase with respect to the AC grid voltage in order to generate the DC current. However, this may lead to problems on the DC side, since the instantaneous values ​​of the DC voltages generated by the individual rectifiers are different and thus circulating currents may flow between the rectifiers. To solve this problem, it is advisable to use a DC interphase reactor or several DC reactors between the two rectifiers.

[0003] Furthermore, it is also known to use one or more DC reactors to avoid harmonics on the DC side. Such DC reactors can be used, for example, in each DC system with one rectifier each. The use of one DC reactor per DC system has the disadvantage that each coil requires a large proportion of iron, since the iron circuit of the DC reactor is completely pre-saturated by the DC current generated to operate the electrolyzer. Furthermore, an amount of iron required per DC reactor or per rectifier used results.

[0004] The interphase reactors connected between the two DC systems can also be very large, because due to the phase shift between the two DC systems, the DC interphase reactor must absorb the difference voltage between the two DC systems. Furthermore, depending on the number of pulses in the system, several interphase reactors for different frequencies may be required in order to achieve sufficient filtering of the harmonics. Furthermore, in this case, these interphase reactors used each require a large core. Due to the high current strength of the DC currents required for industrial electrolysis applications, high demands are placed on the interphase or DC reactors used, which in particular leads to a considerable core size of the reactor and therefore also to considerable dimensions, considerable weight and high costs. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a circuit arrangement which allows for a reduced amount of iron required for a DC reactor. [Means for solving the problem]

[0006] This problem is solved according to the invention in that in a circuit arrangement as mentioned at the beginning, the first coil and the second coil are connected to each other via a connecting part of the coil arrangement which forms the respective cores of both coils.

[0007] A first coil, connected to the DC voltage side of the DC voltage converter of the circuit arrangement, is used as a DC reactor for smoothing the DC current or as a smoothing device for smoothing the DC current or for attenuating harmonics superimposed on the DC current. A second coil, coupled to the first coil via a coupling element as a common core, can function as a compensation coil when energized accordingly, so that in the common coupling element the magnetic flux generated by the second coil cancels the magnetic flux generated by the first coil, which leads to the DC current generated by the rectifier. This results in a complete compensation or at least a partial compensation of the magnetic flux generated by the first coil. This compensation allows the amount of iron in the first coil to be reduced without reducing the inductance of the coil required for smoothing the DC current. In this way, the DC current can be smoothed (or the harmonics can be attenuated) despite the reduced proportion of iron in the first coil.

[0008] The coupling element coupling the first coil and the second coil to each other forms a core of each of the coils, in particular a coil core of the first coil and a coil core of the second coil. Furthermore, the coupling element can extend at least partially inside a turn of the first coil and inside a turn of the second coil. The coupling between the coils generated via the coupling element is a magnetic coupling, so that during operation of the circuit arrangement, the magnetic flux generated by the second coil can oppose the magnetic flux generated by the first coil in the coupling element.

[0009] In order to generate a magnetic flux in the second coil, the second coil is connected to a current source of the circuit arrangement. This current source may be a direct current source, also called a compensation current source, based on the function of the second coil. Instead of a compensation current source and a second coil, the use of a permanent magnet is also possible in principle. However, the use of a second coil connected to a current source advantageously makes it possible to adjust the direct current supplying the second coil, so that different intensities of magnetic flux generated by the second coil or different intensities of compensation can be achieved.

[0010] According to the invention, the coupling part can be an iron core, in particular formed in the shape of a yoke. Forming the coupling part as an iron core allows a magnetic coupling of the first coil and the second coil. The coupling part formed as an iron core can consist of one piece or of several pieces. The yoke-shaped formation of the iron core allows the first coil and the second coil to be arranged, respectively, on one leg of the coupling part. In order to facilitate the assembly of the coil arrangement in the circuit arrangement, the coupling part can in particular comprise a U-shaped or approximately U-shaped element and an I-shaped or approximately I-shaped element. These elements can be assembled in the shape of a yoke by placing the I-shaped element over the opening of the U-shaped element so that a closed yoke of the coupling part results.

[0011] The provision of compensation according to the invention allows the amount of iron to be significantly reduced, in particular to use less iron than would be necessary to avoid saturation if the compensation flux were not taken into account. It can thus be provided that the amount of iron in the yoke-shaped core can be specified to be less than in the case of full saturation of the coil core of the first coil by the maximum current value generated by the rectifier, in particular less than half of it. The magnetic flux generated by the direct current of the first coil is selected without regard for the magnetic flux generated by the second coil.

[0012] With regard to the coil arrangement, according to the invention, the second coil of the coil arrangement may have a larger number of turns than the first coil of the coil arrangement. This has the advantage that the current through the second coil for compensating the magnetic flux generated by the current through the first coil can be smaller than the current through the first coil. In particular in circuit arrangements used for operating electrolyzers used on an industrial scale, very large direct currents can flow through the first coil, so that by increasing the number of turns or turns of the second coil, the second coil can be supplied with a direct current with a low current strength. For example, the first coils can be designed for a direct current with a current strength between 100 A and 1 kA, respectively.

[0013] According to the invention, the circuit arrangement may include a number of rectifiers and a number of coil arrangements, and the first coils of the number of coil arrangements may each be connected to a different one of the number of rectifiers. In particular, each rectifier of the circuit arrangement may be connected to the first coil of one coil arrangement, and thus it is advantageous if there is one coil arrangement for each rectifier. Thus, the first coils of the number of coil arrangements may smooth the DC current that is generated, for example, when operating a number of rectifiers in parallel.

[0014] Furthermore, according to the invention, the second coils of the coil arrangement may be connected in common, in particular in series, to a current source. This allows that, when several rectifiers are operated in parallel and connected respectively to a first coil, the second coils of all coil arrangements can be commonly powered via a current source. When the second coils are connected in series, the compensation current generated by the current source flows through all second coils and is there used to generate the magnetic flux used for compensation. In this way, the current demand of the circuit arrangement according to the invention can be advantageously reduced. The ratio of the number of turns of the first coil to the number of turns of the second coil may be the same or different for each coil arrangement. When several rectifiers are operated with the same output current strength, the number of turns and / or the turn ratio can be respectively the same for several coil arrangements. When several rectifiers are operated with different output current strengths, the turn ratios of several coil arrangements can be different, so that the compensation current through the second coil can be used to generate the compensation of the magnetic flux generated by the current in the first coil.

[0015] According to the invention, it is proposed that the current source is controllable, in particular configured as a rectifier, and / or that the rectifier or rectifiers are controllable and / or configured as a three-phase rectifier, in particular as a B6 rectifier. Due to the controllability of the current source, the magnetic flux generated by the second coil or coils, respectively, is also adjustable, so that the compensation function of the second coil or coils can be adapted to the actual operation of the rectifier or coils. The current source configured as a rectifier can, for example, be fed via the same power grid as the rectifier or coils of the circuit arrangement. The controllability of the rectifier or coils, which are advantageously configured as a three-phase rectifier or a B6 bridge rectifier, makes it possible to adjust the total current generated via the rectifier and thus to control, for example, the operation of an electrolysis device connected to the circuit arrangement.

[0016] In a preferred embodiment of the invention, one or more rectifiers are each connected with their AC voltage side to a secondary winding of at least one transformer of the circuit arrangement. In a circuit arrangement including several rectifiers, a phase shift exists between the secondary windings with respect to the AC voltage supplied to the AC voltage side. The number of secondary windings operated out of phase with respect to the period of the AC voltage supplied to the AC voltage side determines the number of pulses of the circuit arrangement. A transformer can convert, for example, a three-phase voltage supplied to the primary or AC voltage side, in particular a medium or high voltage of a power system, into a three-phase AC voltage with a lower voltage occurring at the secondary winding. This three-phase AC voltage occurring at the secondary winding can subsequently be converted into a DC voltage via a rectifier connected to each secondary winding, or the corresponding three-phase AC current outputted via the secondary winding can be converted into a DC current via a rectifier.

[0017] The electrolyzer according to the present invention includes a circuit arrangement according to the present invention, in which one or more first coils of the circuit arrangement are connected to at least one electrolyzer of the electrolyzer. For example, the first coils of the multiple coil arrangement are connected in parallel to obtain a high total current for operating at least one electrolyzer. For example, the multiple first coils can each be designed for a direct current with a current strength between 100 A and 1 kA, and thus the total current results from the sum of the currents flowing through the first coils.

[0018] All advantages and configurations described above for the circuit arrangement according to the invention apply correspondingly to the electrolysis device according to the invention.

[0019] In the method according to the invention for operating the circuit arrangement according to the invention or the electrolysis device according to the invention, the first coil and the second coil of at least one coil arrangement are energized such that, at least in the common coupling element, the magnetic flux generated by the second coil opposes the magnetic flux generated by the first coil. As a result, a complete or at least partial compensation of the magnetic flux generated by the first coil can be achieved in the part of the coupling element acting as a coil core of the first coil. If a current with a current intensity I1 flows through the first coil, the first coil has n turns (number of turns n) and the second coil has m turns (number of turns m), then for the current flowing through the second coil, a current intensity I2=I1(n / m) can be set, the current directions of I1 and I2 being selected such that the magnetic flux generated by the second coil opposes the magnetic flux generated by the first coil at least in the common coupling element.

[0020] According to the invention, the effective DC current generated by the rectifier(s) and the compensating DC current generated by the current source are adjusted based on a common relative target current setting.

[0021] The setpoint current setting lies, for example, between a 0% value, which corresponds to a blocked state of the circuit arrangement, and a 100% value, which corresponds to a maximum DC current output by the circuit arrangement. At a constant turns ratio between the number of turns n of the first coil of the at least one coil arrangement and the number of turns m of the second coil, the respectively generated magnetic flux is directly proportional to the corresponding current strength of the effective current or compensation current, so that the current source of the circuit arrangement as well as the rectifier can be easily controlled.

[0022] All advantages and embodiments described above with respect to the circuit arrangement according to the invention and the electrolysis device according to the invention apply analogously to the method according to the invention.

[0023] Further advantages and details of the invention emerge from the drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 shows a schematic diagram of a coil arrangement of a circuit arrangement according to the invention. [Diagram 2] FIG. 2 is a schematic diagram showing the circuit connections of an electrolysis device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In Fig. 1, a coil arrangement 1 of a circuit arrangement according to the invention is shown. The coil arrangement 1 has a first coil 2 and a second coil 3. Furthermore, the coil arrangement 1 comprises a connecting part 4. The connecting part 4 consists of a U-shaped element 5 and a substantially I-shaped element 6, which is arranged on the U-shaped element 5 in such a way that the overall shape of the connecting part 4 is yoke-like. The first coil 2 is connected to the second coil 3 via the connecting part 4. Furthermore, the connecting part 4 forms the core of the first coil 2 and the second coil 3, respectively.

[0026] The first coil 2 has n turns (i.e. number of turns n) and the second coil 3 has m turns (i.e. number of turns m). The illustrated number of turns of the first coil 2 and the second coil 3 should be understood purely schematic as an example. For example, the first coil 2 can be designed for a direct current with a current strength between 100 A and 1 kA, and the second coil 3 can also be designed for a smaller current strength according to the turns ratio n / m.

[0027] By coupling the first coil 2 and the second coil 3 via the coupling component 4, a magnetic flux Φ is generated in the coupling component 4 by a current I1 flowing through the first coil 2. DC is the magnetic flux Φ generated by the current I2 flowing through the second coil 3 KOMP This compensation makes it possible to advantageously reduce the amount of iron inside the first coil 2 without significantly affecting its characteristics in terms of smoothing the current I1.

[0028] FIG. 2 shows a circuit arrangement 7 according to the invention. The circuit arrangement 7 comprises four coil arrangements 1 and four rectifiers 8. The DC voltage side of each rectifier 8 is connected to a first coil of the coil arrangement 1, respectively. Furthermore, the circuit arrangement 7 comprises two transformers 9, each of which has a primary winding 10 and two secondary windings 11. The primary windings 10 of the transformers 9 are connected, for example, to a power system, which is, for example, a medium or high voltage power system. The secondary windings 11 of the transformers 9 can each have a phase shift of, for example, 30° with respect to one another. Furthermore, the transformers 9 can be operated such that the primary windings 10 have a phase shift of 15° with respect to one another, so that the illustrated circuit arrangement 7 produces an overall number of 24 pulses.

[0029] The three-phase AC current output from the secondary winding 11 is converted to a DC current by the rectifier 8, which flows through the first coil 2 of the coil arrangement 1 as a current I1. The first coil 2 of the coil arrangement 1, acting as a DC reactor, converts the total DC current I GES The magnetic flux generated in the coupling element 4 by the first coil 2 on the basis of the current I1 can be fully or partially compensated by a current I2 flowing through the second coil 3 of the coil arrangement 1. The second coil 3 of the coil arrangement 1 is connected in series to a current source 12 which generates the current I2.

[0030] The circuit arrangement 7 is a component of an electrolysis device that includes at least one electrolyzer 13, which generates a total direct current I GES The power supply is

[0031] In the case of the same magnitude of current I1, the same turn ratio n / m between the number of turns n of the first coil and the number of turns m of the second coil can be used in each of the coil arrangements 4. In this way, the magnetic flux Φ generated by each first coil 2 due to the current I2 flowing through all second coils 3 through the coil arrangement 1 is DC The same compensation is achieved for each of the magnetic fluxes Φ generated by the current I2 flowing through the second coil 3 connected in series. KOMP Magnetic flux due to Φ DC The full or partial compensation of allows a reduction in the proportion of iron in each first coil 2 while maintaining its inductance, so that the direct current I1 or the total current I generated by the rectifier 8 is reduced. GES Despite the reduced proportion of iron in the first coil 2, no adverse effects occur when smoothing the wire.

[0032] When the circuit arrangement 7 or an electrolysis device including the circuit arrangement 7 is operated in the manner according to the invention, the signs of the currents I1 and I2 are selected such that the first coil 2 and the second coil 3 of the coil arrangement 1 are energized such that, at least in the respective common coupling element 4, the magnetic flux respectively generated by the second coil 3 is energized in opposition to the magnetic flux respectively generated by the first coil 2. The effective direct current I generated by the rectifier 8 is GES and the compensation current I2 generated by the current source 12 are proportional to each other when the turns ratio n / m is the same. Therefore, similar to the compensation by the current I2, the effective DC current or the total DC current I GES The current strengths of the can also be commonly adjusted based on a relative setpoint current setting, which can be, for example, a value between 0%, which corresponds to the interrupted state of the circuit arrangement, and 100%, which corresponds to the maximum DC current output by the circuit arrangement.

[0033] Rectifier 8 is configured as a three-phase rectifier. For example, rectifier 8 can be configured as a B6 bridge rectifier. Current source 12 can also be implemented as a rectifier. For example, current source 12 can be powered via a utility grid that is connected to a primary winding 10 of transformer 9. Similar to rectifier 8, current source 12 can also be configured to be controllable.

[0034] The illustration of the circuit arrangement 7 with four rectifiers 8 is merely an example. A different number of rectifiers 8 and / or a different number of transformers 9 can also be used.

[0035] Although the present invention has been described in more detail by preferred embodiments, the invention is not limited to the disclosed examples, and other variations can be derived by those skilled in the art without departing from the scope of protection of the present invention. [Explanation of symbols]

[0036] 1 Coil device 2 First coil 3 Second coil 4 Connecting parts 5 U-shaped elements 6 I-shaped elements 7 Circuit device 8 Rectifier 9. Transformers 10 Primary Winding 11 Secondary Winding 12 Current source 13 Electrolyser

Claims

1. An electrolysis device comprising a circuit device (7), The circuit device (7) includes a number of transformers (9), each having one primary winding (10) and two secondary windings (11), a number of rectifiers (8) whose AC voltage sides are connected to the two secondary windings (11), respectively, and a number of coil devices (1), each having a first coil (2) and a second coil (3), The first coils (2) are connected to the DC voltage side of the respective separate rectifiers (8) and the second coils (3) are connected together in series to a current source (12) of the circuit arrangement (7), the first coil (2) and the second coil (3) of the coil device (1) are connected to each other via a connecting part (4) of the coil device (1) that forms a core of each of the coils (2, 3), The first coils (2) of the circuit device (7) are connected to at least one electrolyzer (13) of an electrolysis device. Electrolysis equipment.

2. 2. An electrolysis device according to claim 1, characterized in that the connecting part (4) is an iron core.

3. 3. Electrolysis device according to claim 1 or 2, characterized in that the second coil (3) of the coil arrangement (1) has a greater number of turns than the first coil (2) of the coil arrangement (1).

4. 4. An electrolysis device according to claim 1, characterized in that the current source (12) is controllable and configured as a rectifier and / or that the rectifiers (8) are controllable and / or that the rectifiers (8) are configured as three-phase rectifiers.

5. 5. The method for operating an electrolysis apparatus according to any one of claims 1 to 4, characterized in that the first coil (2) and the second coil (3) of the coil arrangement (1) are energized such that a magnetic flux generated by the second coil (3) of the coil arrangement (1) opposes a magnetic flux generated by the first coil (2) of the coil arrangement (1) at least within the common coupling part (4).

6. 6. The method according to claim 5, characterized in that the effective DC currents generated by the plurality of rectifiers (8) and the compensating DC current generated by the current source (12) are adjusted based on a common relative target current setting.

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