Energy supply device for electrolysis unit and electrolysis system
Through the combination of multi-winding transformer and AC/DC converter, the voltage demand caused by electrolytic aging is solved, the problem of voltage exceeding the range of auxiliary unit voltage is avoided, low loss and low cost power supply is achieved, and the efficient operation of electrolytic equipment is ensured. .
Patent Information
- Application Number
- CN202380037909.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-05
- Filing Date
- 2023-04-14
- Publication Date
- 2024-12-13
AI Technical Summary
When the electrolytic device is aging, the DC input voltage needs to be increased to maintain hydrogen productivity, resulting in the AC voltage of the auxiliary unit exceeding the allowable range, and the solution is complex and costly.
Multi-winding transformers with primary and secondary sides are adopted to provide AC voltages of different voltage amplitudes through different secondary side connections, combined with AC/DC converters to power the electrolytic and auxiliary units, avoiding the use of staged switches , reducing conversion losses and costs.
Power supply without significantly increasing power loss when the electrolytic aging is achieved, reducing system costs, ensuring that the voltage of the auxiliary unit is within the standard range, and improving system efficiency and reliability.
Smart Images
Figure CN119137834A_ABST
Abstract
Description
Technical Field
[0001] The present patent application relates to an energy supply device for an electrolysis unit and an electrolysis device having such an energy supply device. Background Art
[0002] Hydrogen can be produced from water by supplying electrical energy to the electrolytic decomposition. Industrial hydrogen production is usually carried out using an electrolyser, which is supplied with power from an energy supply grid (e.g. a medium voltage grid) via a rectifier. It is well known that electrolysers are susceptible to aging and that for a given DC input voltage, the hydrogen production rate of the electrolyser decreases during aging. The hydrogen production rate depends directly on the current throughput of the electrolyser and generally increases with increasing DC input voltage to the electrolyser. In order to achieve a specified hydrogen production rate even when the electrolyser is aged, the DC input voltage to the electrolyser must therefore be increased.
[0003] The problem of an increase in the supply voltage of the electrolyzer as it ages is usually solved in the prior art by means of a transformer with so-called step switches (Stufenschalter), via which the rectifier is connected to the supply grid. The step switches are usually located on the primary side of the transformer, by means of which the transfer ratio of the transformer can be varied. As a result, the voltage amplitude of the AC voltage supplied to the AC side of the rectifier can increase (or decrease) over time. By increasing the AC voltage amplitude, the aging effects of the electrolyzer can be at least partially compensated, without the rectifier having to be operated with significantly higher conversion losses as the electrolyzer ages.
[0004] In addition to the electrolyzer, the electrolysis unit also includes auxiliary units (Hilfsaggregate), such as cooling devices, pumps, heating devices, etc., which supply and discharge the medium required by the electrolyzer with a specified quality (pressure, temperature, etc.). The power supply of the auxiliary units is usually provided via a standardized AC voltage (e.g. 400V, 480V), the voltage amplitude of which usually has a narrow tolerance range. The transfer ratio of the transformer is changed by the primary-side stepping switch, which also has an impact on the secondary-side AC voltage that supplies the auxiliary units, because this voltage will also increase and, if no further countermeasures are taken, will exceed the permissible tolerance range.
[0005] In order to avoid an increase in the AC voltage for the auxiliary unit, a method is known according to Figure 1 The electrolysis device 150 of the present invention is designed to have an energy supply device 100 and an electrolysis unit 120. The energy supply device 100 comprises two separate transformers 102, 104, the primary side of each transformer being connected to the energy supply grid 40 via a grid connection 115 of the energy supply device 100. The electrolyzer 22 of the electrolysis unit 120 is supplied with a DC input voltage U via the first transformer 104. DC，EL. For this purpose, the secondary side of the first transformer 104 is connected to the DC voltage input 21 of the electrolyzer 22, by which the electrolyzer 22 of the electrolysis unit 120 is supplied, via the AC separation unit 105, the AC / DC converter 106, the DC separation unit 112 and the DC voltage output 116 of the energy supply device 100. The second transformer 102 is used to provide a standardized AC voltage to the auxiliary units 23, 24 of the electrolysis unit 120, and for this purpose, the second transformer 102 is connected to the auxiliary units 23, 24 of the electrolysis unit 120 on the secondary side via the auxiliary power output 117 of the energy supply 100. Only the first transformer 104 has a step switch, while the second transformer 102 has no step switch, in order to compensate for the aging effects of the electrolyzer 22. Although the second transformer 102 does not require a stepping switch and its rated power is usually designed to be significantly lower than the rated power of the first transformer 104, and although the two transformers 102, 104 do not necessarily have to be designed as multi-winding transformers, the overall solution is still costly, especially when the energy supply grid 40 is a medium-voltage grid and the second transformer 102 is designed as a separate medium-voltage transformer.
[0006] Figure 2 Another conventional variant of an electrolysis device 250 is shown with an energy supply device 200 and an electrolysis unit 220. Here, the energy supply unit 200 comprises a transformer 202, which is designed as a multi-winding transformer with a first secondary side and a second secondary side, which is connected to the energy supply grid 40 on the primary side via a grid connection 215 of the energy supply device 200. The auxiliary units 23, 24 of the electrolysis unit are supplied with power via the first secondary side of the transformer 202. The second secondary side is used to supply a DC input voltage U to the electrolyzer 22 of the electrolysis unit 220. DC，EL. For this purpose, it is connected to the DC input 21 of the electrolyzer 22 via the AC isolation device 205, the AC / DC converter 206, the DC isolation device 212 and the DC voltage output 216 of the energy supply device 200. In order to compensate for the aging effects of the electrolyzer 22, the transformer 202 has a stepping switch on the primary side, by which the voltage amplitude of the AC voltage supplied to the AC / DC converter 206 can be increased. In order that the change in the transmission ratio caused by the stepping switch of the transformer 202 does not affect the AC voltage of the auxiliary units 23, 24 connected to the auxiliary power output 17, the second transformer 204 also has a stepping switch. The stepping switch of the second transformer 204 now operates in the opposite direction to the stepping switch of the transformer 202, so that the AC voltage on the secondary side of the second transformer 204 (facing the auxiliary units 23, 24) is reduced again. This allows to compensate for the voltage increase of the transformer 202 when supplying the auxiliary units 23, 24 and reset it to the standard value required by the auxiliary units. In this conventional variant, a low-voltage transformer (not necessarily necessarily designed as a multi-winding transformer) can be used as the second transformer 204. However, it must also have an additional step switch. Such a transformer equipped with a step switch is usually more expensive than a transformer without a step switch. Figure 1 and Figure 2 Traditional solutions are complex, expensive and often error-prone to implement.
[0007] Document CN 202930937 U discloses an energy supply system for an electrolytic cell, which includes an AC step-down station, an electric energy conversion station for converting AC power into DC power, and an electrolytic cell. The electric energy conversion station includes an input-side AC current sampling circuit and an input-side AC voltage sampling circuit, a load voltage regulator, a rectifier transformer, a rectifier, a controller, a filtering and power compensation device, an output-side DC current sampling circuit, and an output-side DC voltage sampling circuit. This design of the electric energy conversion station greatly reduces the power loss caused by harmonics in the rectifier transformer.
[0008] Document WO 2009 / 144266 A1 discloses a three-phase rectifier circuit having two or more transformers connected to an AC grid in parallel on the primary side and each connected to at least one semiconductor rectifier bridge on the secondary side. The rectifier bridges connected to different transformers are connected in series on the DC side to provide DC power to power consuming devices. One of the rectifier bridges is a thyristor rectifier bridge, and the remaining rectifier bridges are diode rectifier bridges.
[0009] GB 778989A discloses an electrolysis device with multiple electrolysis loads, each of which is powered via its own multi-phase rectifier through a separate star-connected secondary winding set of a transformer. The transformer has two sets of primary windings connected to a three-phase power supply. If an error occurs, only the affected electrical equipment will be shut down.
[0010] Document DE 897 696 B discloses an electrolysis device having an electric pump, a liquid container and an electrolytic cell which pumps the liquid from the container. The electrolyser comprises a grid transformer, a rectifier and a voltage regulator for supplying power to the electrolytic cell and an auxiliary transformer and rectifier for operating a motor for pumping brine into the electrolytic cell. Summary of the invention
[0011] The object of the present invention is to provide an energy supply device for an electrolysis unit which, despite the gradual aging of the electrolyzer, does not generate any or at least does not significantly increase the power losses associated with the conversion when supplying energy to the electrolyzer. The energy supply device should also be as cost-effective as possible. Another object of the present invention is to provide an electrolysis device having these characteristics.
[0012] The energy supply device for an electrolytic cell according to the present invention comprises the following:
[0013] - a grid connection for connecting the energy supply device to an energy supply grid,
[0014] - a DC voltage output for connecting an electrolyser of an electrolysis cell, and
[0015] - an auxiliary power output for connecting at least one auxiliary unit of the electrolysis unit.
[0016] The energy supply device further comprises a first multi-winding transformer, the first multi-winding transformer having a primary side and a secondary side, the primary side being connected to a grid connection of the energy supply device, the secondary side having a first secondary side connection and a second secondary side connection, the first secondary side connection being electrically isolated from the secondary side connection. The first secondary side connection is connected to the auxiliary power output and is designed to provide a first voltage amplitude The second secondary-side connection is connected to the AC connection of the first AC / DC converter operating as a rectifier and is designed to provide an AC voltage having a second voltage amplitude The DC connection of the first AC / DC converter is connected to the DC output of the energy supply device. The energy supply device also includes a second transformer, which has a primary side connected to the grid connection and a secondary side. The secondary side of the second transformer has a third secondary side connection, which is designed to provide a third voltage amplitude The third secondary-side connection is connected to the AC connection of the second AC / DC converter. The DC connection of the second AC / DC converter is connected to the DC output. The primary side and the first secondary-side connection of the first multi-winding transformer or the primary side and the secondary side of the first multi-winding transformer do not have a step switch, respectively.
[0017] In addition to the first multi-winding transformer and the second transformer, the energy supply device may also include one or possibly more additional transformers. The one or more additional transformers may each have their primary side connected to the grid connection via an AC / DC converter as a rectifier and their secondary side connection to the DC voltage output of the energy supply device, or, in the case where the transformers each have two electrically isolated secondary side connections, may also have their secondary side connection to the DC voltage output of the energy supply device via two AC / DC converters as rectifiers. The additional transformers may each be designed as a multi-winding transformer. The additional transformers may, but do not necessarily, each have a stepping switch.
[0018] A multi-winding transformer is a transformer that includes a corresponding plurality of windings for each phase of an AC voltage on its primary side and / or secondary side. For example, a three-winding transformer may include one winding on its primary side and two windings on its secondary side in each phase. Thus, a four-winding transformer may have two primary windings and two secondary windings per phase. In the multi-winding transformers mentioned here, the two secondary windings of each phase are usually electrically isolated from each other. Alternatively, it is also feasible that one or more multi-winding transformers each have two secondary windings connected in parallel. If there are two primary windings per phase (for example in a four-winding transformer), they can be electrically connected to each other, in particular in parallel to each other. For a multi-winding transformer with two electrically isolated secondary windings per phase, two different transmission ratios can be used to convert the AC voltage on the primary side into two secondary AC voltages with different voltage amplitudes.
[0019] For the electrolytic reaction, the electrolyzer needs a chemical medium with predetermined chemical and / or physical properties. The electrolytic reaction converts the medium into other media, and once converted, it must be transported away again. The auxiliary unit of the electrolysis unit is used to supply chemical substances to the electrolyzer, and is a unit that needs to transport the chemical medium to the electrolyzer and / or transport the chemical medium away from the electrolyzer. Alternatively or additionally, the auxiliary unit can also be used to prepare chemical media so that they reach and / or maintain their predetermined chemical or physical properties. Therefore, such auxiliary units (for example, for producing hydrogen from water by electrolysis) can particularly include air pumps, liquid pumps, gas compressors, gas drying units, cleaning units for water purification, cooling units or heating units. The electrolysis unit can generally include multiple identical and / or different auxiliary units.
[0020] In the energy supply device according to the invention, the first multi-winding transformer is used to supply the auxiliary unit of the electrolysis unit with a first voltage amplitude by means of its first secondary-side connection. The second secondary winding and the second voltage amplitude provided therein The AC voltage of the first AC / DC converter is rectified and fed to the DC voltage output of the energy supply device and then fed to the DC input of the electrolyzer to power it. The second transformer can be, but does not have to be, a multi-winding transformer. The third voltage amplitude is provided at the third secondary side connection via the second transformer. The AC voltage is rectified via a second AC / DC converter and fed to a DC voltage output of the energy supply device and subsequently to a DC input of the electrolyzer to power it. The two AC / DC converters connected to the DC input of the electrolyzer do not have to be started at the same time and supply power to the electrolyzer. On the contrary, at low hydrogen productivity, and thus at low power conversion relative to its rated power, the electrolyzer can first be powered by the second AC / DC converter instead of the first AC / DC converter. In addition, the first AC / DC converter can only be connected to the second AC / DC converter when the electrolyzer has a higher power conversion level (closer to the rated power of the electrolyzer). Specifically, it is feasible to start the electrolyzer using the second AC / DC converter instead of the first AC / DC converter, and it is also feasible to operate the electrolyzer at partial load. By selecting the transmission ratio of the second secondary-side connection and the third secondary-side connection, the second voltage amplitude Greater than the third voltage amplitude In particular, it is always greater than the third voltage amplitude The power losses occurring during the operation of the electrolysis unit or the energy supply device can be minimized, wherein the entire operating range of the electrolyzer in its current-voltage diagram can be reached with at least one AC / DC converter (if necessary, also two AC / DC converters). This also applies if the DC voltage provided by the DC input of the electrolyzer increases due to aging.
[0021] Since the primary side and the first secondary side connection of the first multi-winding transformer or the primary side and the secondary side of the first multi-winding transformer respectively do not have a step switch, the first voltage amplitude of the AC voltage applied to the first secondary side connection is constant over time, in particular as the electrolyser ages. It can therefore always correspond to the standardized AC voltage required for the auxiliary units of the electrolysis cell. If the entire first multi-winding transformer also does not have a tapping switch, this also applies in a corresponding manner to the second voltage amplitude applied to the second secondary-side connection. AC voltage. The first multi-winding transformer can therefore be designed cost-effectively. The second transformer can also be designed cost-effectively, in particular if it is not designed as a multi-winding transformer and also without a stepping switch. Nevertheless, in the energy supply device according to the invention, the first multi-winding transformer and the second transformer can be optimally utilized in terms of their energy supply. This applies in particular to the first multi-winding transformer, which supplies the auxiliary unit via its first secondary-side connection and supplies the electrolyzer via its second secondary-side connection. Overall, this makes the energy supply device for the electrolysis unit cost-effective, and even if the electrolyzer ages, its conversion losses do not increase significantly.
[0022] In an advantageous embodiment of the energy supply device, the second transformer can also be designed as a multi-winding transformer, the secondary side of which has a fourth secondary connection in addition to the third secondary connection. The fourth secondary connection is designed to provide a fourth voltage amplitude It is connected to the AC connection of a third AC / DC converter, the DC connection of which is connected to the DC output of the energy supply device. Advantageously, the fourth voltage amplitude Less than the second voltage amplitude The fourth voltage amplitude Can be equal to the third voltage amplitude But advantageously different therefrom. In this way, the AC / DC converter can cover the operating range of the electrolyzer when generating a DC input voltage for the electrolyzer, so that during operation, each AC / DC converter covers a different voltage range, within which it works particularly efficiently and with low conversion losses. The voltage ranges of different AC / DC converters can advantageously overlap. This does not mean that in each voltage range, only the AC / DC converter assigned to that voltage range is operated. On the contrary, multiple (in particular all) AC / DC converters can operate simultaneously within each voltage range or within each voltage range. However, the AC / DC converter assigned to this voltage range operates with particularly low conversion losses relative to other AC / DC converters. Regardless of whether the second transformer is a second multi-winding transformer, it can advantageously include a step switch on its primary side or secondary side. If the step switch is arranged on the secondary side, the transmission ratio of only one of the secondary side connections from the third secondary side connection and the fourth secondary side connection can be changed. Since the second transformer has a stepped switch, an increase in conversion losses that occurs when the electrolyzer ages during operation of the functional device can be further minimized.
[0023] In another embodiment of the energy supply device, the first AC / DC converter can be designed as a transistor-based AC / DC converter. The transistor-based AC / DC converter has a bridge circuit, the bridge circuit has a plurality of bridge branches, each bridge branch includes a series connection of at least two transistors. Each transistor may have a separate or intrinsic diode connected in reverse parallel to the transistor. Specifically, each transistor may be designed as an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOSFET). During operation, the transistor-based AC / DC converter generates only a small amount of unwanted reactive power at its AC connection, which is transmitted to the energy supply grid and / or from the first secondary side connection to the second secondary side connection via the grid connection as an interference signal. In any case, the interference signal of the transistor-based AC / DC converter is significantly smaller than the interference signal of the thyristor-based AC / DC converter. In addition, compared with the thyristor-based AC / DC converter, the transistor-based AC / DC converter is constructed to generate a bidirectional power flow, that is, it can not only work in a rectifier mode, but also in an inverter mode (wechselrichten). In this way, it is also possible to generate the required reactive power to at least partially compensate for the reactive power generated or present elsewhere. Since the first AC / DC converter is based on transistors, the interference signal generated at the second secondary side connection is particularly low. Therefore, the interference signal crosstalked to the first secondary side connection (which may have an adverse effect on the operation of the auxiliary unit there) is also relatively low. In addition to the first AC / DC converter, at least one other AC / DC converter (e.g., the second AC / DC converter and / or the third AC / DC converter) can also be constructed as a transistor-based AC / DC converter. In this way, the second AC / DC converter and / or the third AC / DC converter can be operated in such a way that it generates a compensating reactive power that at least partially compensates for the undesirable reactive power that would otherwise exist (e.g., the undesirable reactive power at the grid connection).
[0024] In another embodiment of the energy supply device, at least one AC / DC converter, or each AC / DC converter, can have its AC connection connected to a transformer assigned to it via an AC separation unit having a precharging device, the transformer consisting of a first multi-winding transformer and a second transformer. The precharging device is used to limit the current when a capacitor that has not yet been charged or is not fully charged is connected. Such a precharging device can be actively controlled or passive (uncontrolled). For example, a passively designed precharging device can have a path connected in series by a precharging resistor and a switch, and another switch connected in parallel with the series connection. An actively controlled precharging device can be, for example, a DC / DC converter designed to work in a step-down manner in the direction of power flow.
[0025] In another embodiment of the energy supply device, a DC separation unit can be arranged between each AC / DC converter and the DC voltage output. However, each DC separation unit does not necessarily include a pre-charging device. For example, a DC separation unit, or it can be a plurality of DC separation units, may not have a pre-charging device. Such a pre-charging device in the DC separation unit is generally used to limit the current when the electrolyzer starts, because the electrolyzer also exhibits capacitive properties at its DC input, especially in the startup phase. In the energy supply device provided here, in principle, only one of the DC separation units needs to be provided with a pre-charging device, especially a DC separation unit activated when the electrolyzer is turned on. The capacitors of the DC connection of those AC / DC converters with an open DC separation unit and therefore not yet conductively connected to the electrolyzer can be pre-charged by the corresponding AC separation unit assigned to them, and the AC separation unit includes a pre-charging device. In this case, each DC separation unit associated with these AC / DC converters can be closed only when the potentials of the two contacts of the corresponding DC separation unit are very close to each other, and therefore the voltage between the contacts is very low, so that high instantaneous power flow can be avoided when the corresponding DC separation unit is closed. Therefore, one or more corresponding DC separation units can be designed to have no pre-charging device, so that the energy supply device can achieve particularly high energy efficiency.
[0026] In the energy supply device, the second transformer can also be designed as a multi-winding transformer. If the first multi-winding transformer and the second transformer designed as multi-winding transformers have the same rated power, a plurality of identical transformers can be used within the energy supply device. However, the rated power levels of the first multi-winding transformer and the second transformer are usually calibrated to the rated power of the electrolyzer and the auxiliary unit and are therefore different from each other. Specifically, the rated power of the first multi-winding transformer can exceed the rated power of the second transformer.
[0027] The first multi-winding transformer of the energy supply device can be designed so that the second secondary-side connection has a higher rated power than the first secondary-side connection. In particular, the second secondary-side connection can have a rated power that differs by at least 10%, in particular at least 10% higher. It is particularly advantageous if the rated power P(2S2) of the second secondary-side connection is 1.5 to 2.5 times the rated power P(2S1) of the first secondary-side connection, i.e. 1.5*P(2S1)≤P(2S2)≤2.5*P(2S1). This is particularly true when the rated power of the electrolyzer significantly exceeds the rated powers of all auxiliary units of the electrolysis unit.
[0028] Advantageously, the rated power P(2S2) of the second secondary-side connection can also be greater than the rated power P(4S3) of the third secondary-side connection and also greater than the rated power P(4S4) of the fourth secondary-side connection (if present). Specifically, for example, if the second transformer is designed as a second multi-winding transformer, the rated power P(2S2) of the second secondary-side connection can be greater than half of the total rated power available on the secondary side of the other transformer, i.e., P(2S2)>0.5*[P(4S3)+P(4S4)]. It is particularly advantageous that the first AC / DC converter assigned to the second secondary-side connection is connected to the electrolyzer by closing the corresponding DC separation unit only when the electrolyzer has a higher consumption and therefore only when the DC input of the electrolyzer has a higher DC voltage.
[0029] If the rated power P(2S2) of the second secondary-side connection exceeds the rated power P(4S3) of the third secondary-side connection and also exceeds the rated power P(4S4) of the fourth secondary-side connection, the second voltage amplitude at the second secondary-side connection It can also be greater than the third voltage amplitude and may also be greater than the fourth voltage amplitude (if present). This allows different power ratings of the secondary-side connection to be preset at least in part by different voltage amplitudes. Thus, the use of material necessary to increase the conductor cross-sectional area at higher rated currents can be compensated or at least reduced.
[0030] If the second transformer of the energy supply device is designed as a second multi-winding transformer, it is advantageous to design the rated powers of the secondary-side connections (here the third secondary-side connection and the fourth secondary-side connection) to be as identical as possible in order to make the multi-winding transformer as easy to manufacture as possible. However, in order to operate the electrolysis plant with the lowest possible conversion-related power losses of the energy supply device, it is advantageous not to design the rated powers of the secondary-side connections to be identical, but to deliberately make them different, since this results in different DC voltages within the operating range of the electrolyzer, within which at least one AC / DC converter connected to the electrolyzer operates as efficiently as possible. It has been found that the rated power P(4S3) of the third secondary-side connection is preferably designed to be different from the rated power P(4S4) of the fourth secondary-side connection, but should not differ from the rated power P(4S4) of the fourth secondary-side connection by more than 40%. Specifically, it is therefore advantageous that the rated power P(4S3) of the third secondary-side connection corresponds to the rated power P(4S4) of the fourth secondary-side connection by a multiple of up to 0.6 to 1.4 (i.e. the following relationship applies: 0.6*P(4S4)≤P(4S3)≤1.4*P(4S4)).
[0031] The energy supply grid may be a low-voltage grid, wherein the energy supply device, in particular the energy supply device regarding the first multi-winding transformer and the second transformer, is configured for connection to the low-voltage grid. However, if the rated power of the electrolyzer is higher, the energy supply grid may also be a medium-voltage grid. In this case, the energy supply device may be designed for connection to the medium-voltage grid.
[0032] In one embodiment, the first multi-winding transformer can be constructed as a three-winding transformer with one primary winding and two separate (i.e. electrically isolated) secondary windings, whereby the first multi-winding transformer and the energy supply device can be realized particularly cheaply. However, from a technical point of view, a four-winding transformer provides a better decoupling of its secondary-side connection. In particular, in a four-winding transformer, interference signals generated by the first AC / DC converter at its AC connection (and therefore present at the second secondary-side connection) can generate less crosstalk to the first secondary-side connection. Compared with a three-winding transformer, interference signals from the second secondary-side connection to the first secondary-side connection can be better suppressed in a four-winding transformer, thereby achieving a power supply that is insensitive to interference of the auxiliary unit. Alternatively, therefore, the first multi-winding transformer can also be designed as a four-winding transformer with two primary windings and two separate (i.e. electrically isolated) secondary windings. The same applies to the second transformer.
[0033] The electrolysis device according to the invention comprises an electrolysis cell with an electrolyzer and at least one auxiliary unit for the chemical supply of the electrolyzer. The electrolysis device also comprises an energy supply device according to the invention, the DC voltage connection of which is connected to the electrolyzer and the auxiliary power output of which is connected to at least one auxiliary unit of the electrolysis cell. This results in the advantages already listed in relation to the energy supply device. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The present invention will be described below with the aid of the accompanying drawings. In the accompanying drawings:
[0035] Figure 1 A conventional electrolysis apparatus in a first variant is shown,
[0036] Figure 2 A conventional electrolysis device in a second variant.
[0037] Figure 3 An electrolysis device having an energy supply device according to the invention is shown according to one embodiment of the invention. DETAILED DESCRIPTION
[0038] Figure 3 An electrolysis device 50 according to the invention is shown with an energy supply device 10 according to the invention. The electrolysis device 50 comprises an energy supply device 10 according to the invention, an electrolysis cell 20 and a control unit 30.
[0039] The energy supply device 10 is described in detail below. The energy supply device 10 is connected to the energy supply grid 40 via the grid connection 15. The AC separation unit 3 is arranged between the grid connection 15 and each of the transformers 2 and 4. The first transformer 2 is a multi-winding transformer having a primary side 2P connected to the grid connection 15 and a secondary side 2S. The secondary side 2S has a first secondary side connection 2S1 and a second secondary side connection 2S2. The first secondary side connection 2S1 is connected to the electrolysis unit 20 via the auxiliary power output 17, and supplies the electrolysis unit 20 with a first voltage amplitude The second secondary side connection 2S2 is connected to the AC connection 6.1 of the first AC / DC converter 6 via the AC separation unit 5 with the pre-charging device VL and provides it with a second AC voltage amplitude The DC connection 6.2 of the first AC / DC converter 6 is connected to the DC voltage output 16 via the output capacitor 9 and the DC separation unit 11. The first AC / DC converter 6 is operated in a rectifier mode when the electrolysis device 50 is in operation and can convert the AC voltage at its AC connection 6.1 into a DC voltage at its DC connection 6.2, which is also applied to the DC voltage output 16 of the energy supply device 10 when the DC separation unit 11 is closed.
[0040] For example, the second transformer 4 is also designed as a multi-winding transformer and has a primary side 4P and a secondary side 4S. The secondary side 4S has a third secondary side connection 4S3 and a fourth secondary side connection 4S4. The third secondary side connection 4S3 is connected to the AC connection 7.1 of the second AC / DC converter 7 via the AC separation unit 5 with a pre-charging device and provides it with a third AC voltage amplitude In addition, the second AC / DC converter 7 is connected to the DC voltage output 16 via the DC connection 7.2 via the capacitor 9 and the DC separation unit 12 with the pre-charging device VL. The second AC / DC converter 7 can convert the AC voltage at the AC connection 7.1 into a DC voltage at the DC connection 7.2, which is then applied at the DC voltage output 16.
[0041] The fourth secondary-side connection 4S4 is connected to the AC connection 8.1 of the third AC / DC converter 8 via the AC separation unit 5 with precharging device and supplies it with a fourth voltage amplitude In addition, the third AC / DC converter 8 is connected to the DC voltage output 16 via its DC connection 8.2 via the output capacitor 9 and the DC separation unit 11. The third AC / DC converter 8 can convert the AC voltage at the AC connection 8.1 into a DC voltage at its DC connection 8.2, and then the DC voltage is applied to the DC voltage output 16. In other words, the AC / DC converters 6, 7, 8 can respectively convert the AC voltage at the AC connection 8.1 into a DC voltage at the DC connection 8.2. The AC voltage is converted into a DC voltage and connected to the DC voltage output 16 so that the DC voltage appears at the DC voltage output 16. The first AC / DC converter 6 and other AC / DC converters 7 and 8 (if applicable) can be transistor-based AC / DC converters. All AC separation units 3, all AC separation units 5 with pre-charging devices, all DC separation units 11 and DC separation units 12 with pre-charging devices, and AC / DC converters 6, 7, 8 are controlled by the control unit 13 of the energy supply device 10 (if necessary, they can also be controlled in combination with the main control unit 30).
[0042] exist Figure 3 In the figures, the output capacitors 9 are shown as separate components, which are connected to the DC connections 6.2, 7.2, 8.2 of the AC / DC converters 6, 7, 8 assigned to them. However, as an alternative, the output capacitors 9 can also be at least partially or completely integrated into the AC / DC converters 6, 7, 8 assigned to them respectively, and thus become part of the AC / DC converters 6, 7, 8 assigned to them respectively.
[0043] The electrolysis unit 20 is described in detail below. The electrolysis unit 20 has an electrolyzer 22, an auxiliary unit 23 (which may be a pump), an auxiliary unit 24 (which may be a heater), and a control unit 25 of the electrolysis unit 20. Figure 3 Only two auxiliary units are shown as an example. However, within the scope of the invention, the electrolysis unit 20 can also have a different number of auxiliary units, in particular more than two auxiliary units, which are also powered via the auxiliary power output 17 of the energy supply device 10. The DC input of the electrolyzer 22 is connected to the DC output 16 of the energy supply device 10 and is supplied with DC power by the energy supply device. The auxiliary units 23, 24 are supplied with AC voltage by the energy supply device 10 via the auxiliary power output 17. The control unit 25 of the electrolysis unit controls the electrolyzer 22 and the auxiliary units 23, 24.
[0044] The control unit 30 of the electrolysis device 50 issues control commands to both the energy supply device 10 and the electrolysis unit 20, and operates as a superior control unit during the operation of the electrolysis device 50. The control unit 30 thus enables the energy supply device 10 and the electrolysis unit 20 to be controlled in such a way as to ensure the smooth operation of the electrolysis unit 20. The superior control unit 30 Figure 3 However, alternatively, the higher-level control functions can also be processed in the control unit 13 of the energy supply device 10 and / or the control unit 25 of the electrolysis unit 22. In this case, the higher-level control unit 30 may not exist as a separate component, but be divided into at least one of the control units 13, 25.
[0045] The operation of the electrolysis device 50 is described below by taking the startup of the electrolysis device 50 as an example. For this purpose, it is assumed that all AC separation units 3, 5 and all DC separation units 11, 12 are disconnected. In addition, for example, the transmission ratio of the transformers 2, 4 is selected so that for the voltage amplitude satisfy: First voltage amplitude The value required for supplying the auxiliary units 23, 24 via the transmission ratio assigned to the first secondary-side connection 2S1 of the first multi-winding transformer 2 is set to, for example, 400 V or 480 V. This is usually less than the second voltage amplitude It may also be optionally smaller than the fourth voltage amplitude Or it can also be smaller than the third voltage amplitude First, the AC separation unit 3 is closed, thereby generating a voltage amplitude of AC voltage is generated and supplied to the auxiliary units 23, 24 of the electrolysis unit 20. These auxiliary units 23, 24 can thus take over the chemical supply of the electrolyzer 22 and put it into operation, via the control unit 25 of the electrolysis unit 20. In addition, the AC separation unit 5 assigned to the third secondary-side connection 4S3 and other AC separation units 5 that are still in the disconnected state (if applicable) are closed. The pre-charging device VL contained in the AC separation unit 5 now performs a current-limited pre-charging of the output capacitor 9 assigned to the second AC / DC converter 7, and also performs a current-limited pre-charging of the output capacitor 9 assigned to the other AC / DC converters 6, 8 (if applicable). Due to the voltage amplitude The minimum possible voltage applied to the output capacitor 9 may also be different. Subsequently, the DC separation unit 12 with the pre-charging device VL is closed, thereby pre-charging the DC input of the electrolyzer 22 via the second AC / DC converter 7. If the DC voltage U provided via the second AC / DC converter 7 DC,EL When the open circuit voltage U0 of the electrolyzer 22 is reached or exceeded, the electrolysis reaction begins to occur therein.
[0046] The start-up and partial load operation of the electrolyser 22 can be carried out only by means of the second AC / DC converter 7. The increased power consumption of the electrolyser 22 is increased by means of the DC voltage U provided at the DC voltage output 16. DC,EL If the DC voltage U at the DC input of the electrolyzer 22 is DC,EL If the DC voltage present at one of the other output capacitors 9 is sufficiently close, the remaining DC separation units 11 can be closed, each of which is assigned to an AC / DC converter 6, 8 that is not yet connected to the electrolyzer 22. Since the DC voltage applied to the output capacitor 9 is sufficiently close to the DC voltage applied to the DC input of the electrolyzer 22, the corresponding DC separation unit 11 can be designed without a pre-charging device VL.
[0047] The above operation has been explained by the example of starting the electrolysis device 50 and then increasing the power of the electrolyzer 22, wherein the AC / DC converters 6, 7, 8 are sequentially connected to the electrolyzer 22 through the DC separation units 11, 12 assigned thereto. If the power of the electrolyzer 22 is reduced, the AC / DC converters 6, 7, 8 can be separated again in the reverse order by disconnecting the corresponding DC separation units 11, 12.
[0048] Reference numerals list
[0049] 2 (First) Multi-winding Transformer
[0050] 2P Primary Side
[0051] 2S Secondary side
[0052] 2S1 First secondary side connection
[0053] 2S2 Second secondary side connection
[0054] 3 AC separation unit
[0055] 4 (Second) Transformer
[0056] 4P Primary Side
[0057] 4S Secondary Side
[0058] 4S3 Third secondary side connection
[0059] 4S4 Fourth secondary side connection
[0060] 5 AC separation unit (with pre-charging device VL)
[0061] 6, 7, 8 AC / DC converter
[0062] 6.1, 7.1, 8.1 AC connection
[0063] 6.2, 7.2, 8.2 DC connection
[0064] 9 Output capacitor
[0065] 10 Energy supply device
[0066] 11 DC separation unit (without pre-charging device)
[0067] 12 DC separation unit (with pre-charging device)
[0068] 13 Control unit (of energy supply equipment)
[0069] 15 Grid connection
[0070] 16 DC output
[0071] 17 Auxiliary power output
[0072] 20 Electrolysis Unit
[0073] 21 DC input
[0074] 22 Electrolyzer
[0075] 23 Auxiliary unit (pump)
[0076] 24 Auxiliary unit (heating)
[0077] 25 Control unit (electrolysis unit)
[0078] 30 Control unit (of electrolysis equipment)
[0079] 40 Energy grid
[0080] 50 Electrolysis equipment
[0081] 100, 200 Energy Supply Device
[0082] 102, 104, 202 Transformer
[0083] 103, 203 AC separation unit
[0084] 105, 205 AC separation unit (with pre-charging device VL)
[0085] 106, 206 AC / DC converter
[0086] 106.1, 206.1 AC connection
[0087] 106.2, 206.2 DC connection
[0088] 112, 212 DC separation unit (with pre-charging device VL)
[0089] 115, 215 Grid connection department
[0090] 116, 216 DC output
[0091] 117, 217 Auxiliary power output
Claims
1. A power supply device (10) for an electrolysis unit (20), the power supply device comprising: - a grid connection part (15) for connecting to an energy supply grid (40); - a direct voltage output (16) for connecting an electrolyser (22) of the electrolysis unit (20); - an auxiliary power output (17) for connecting at least one auxiliary unit (23, 24) of the electrolysis unit (20); a first multi-winding transformer (2), the first multi-winding transformer having a primary side (2P) and a secondary side (2S) connected to the grid connection (15); the energy supply device also having: - a second transformer (4) having a primary side (4P) connected to the grid connection (15) and a secondary side (4S), Features: - the secondary side (2S) of the first multi-winding transformer (2) has a first secondary side connection (2S1) and a second secondary side connection (2S2) electrically isolated from the first secondary side connection, -in, The first secondary side connection portion (2S1) provides a first voltage amplitude and connected to the auxiliary power output (17), and - wherein the second secondary side connection portion (2S2) provides a second voltage amplitude and connected to an AC connection portion (6.1) of a first AC / DC converter (6), a DC connection portion (6.2) of the first AC / DC converter being connected to the DC voltage output (16), and - wherein the secondary side (4S) of the second transformer (4) has a third secondary side connection portion (4S3), and the third secondary side connection portion (4S3) provides a third voltage amplitude and connected to an AC connection portion (7.1) of a second AC / DC converter (7), a DC connection portion (7.2) of the second AC / DC converter being connected to the DC voltage output (16), and -Wherein, the primary side (2P) of the first multi-winding transformer (2) and the first secondary side connection part (2S1) of the first multi-winding transformer (2) or the primary side (2P) of the first multi-winding transformer (2) and the secondary side (2S) of the first multi-winding transformer (2) do not have a step switch respectively.
2. The energy supply device (10) according to claim 1, in, The secondary side (4S) of the second transformer (4) has a fourth secondary side connection portion (4S4), and the fourth secondary side connection portion (4S4) provides a fourth voltage amplitude The AC connection part (8.1) is connected to the third AC / DC converter (8), and the DC connection part (8.2) of the third AC / DC converter (8) is connected to the DC voltage output (16).
3. The energy supply device (10) according to claim 1 or 2, in, The second transformer (4) has a step switch on its primary side (4P) or its secondary side (4S).
4. Energy supply device (10) according to any one of the preceding claims, in, At least one of the AC / DC converters (6-8), optionally each of the AC / DC converters (6, 7, 8) is connected on the AC side via an AC separation unit (5) having a precharging device (VL) to a transformer (2, 4) respectively assigned to the AC / DC converter.
5. Energy supply device (10) according to any one of the preceding claims, It is characterized in that A DC separation unit (11, 12) is arranged between each of the AC / DC converters (6-8) and the DC voltage output (16), wherein one of the DC separation units (11) and optionally a plurality of the DC separation units (11) do not have a pre-charging device (VL).
6. Energy supply device (10) according to any one of the preceding claims, in, The second voltage amplitude Greater than the third voltage amplitude Optionally, it is also greater than the fourth voltage amplitude 7. Energy supply device (10) according to any one of the preceding claims, in, The second transformer (4) is designed as a multi-winding transformer, and the first multi-winding transformer (2) and the second transformer (4) have the same rated power.
8. Energy supply device (10) according to any one of the preceding claims, in, The rated power of the second secondary-side connection (2S2) differs from the rated power of the first secondary-side connection (2S1) by at least 10%.
9. Energy supply device (10) according to any of the preceding claims, insofar as it refers to claim 2, in, The rated power of the third secondary-side connection P( 4S3 ) is different from the rated power P( 4S4 ) of the fourth secondary-side connection P( 4S4 ).
10. Energy supply device (10) according to any one of the preceding claims, in, The rated power of the second secondary-side connection (2S2) is higher than half the rated power present at the secondary side (4S) of the second transformer (4), ie P(2S2)>0.5*P(4S) applies.
11. Energy supply device (10) according to any one of the preceding claims, in, The energy supply device (10) is designed to be connected to a medium-voltage power grid as an energy supply grid (40).
12. Energy supply device (10) according to any one of the preceding claims, in, The first multi-winding transformer (2) is designed as a three-winding transformer having a primary winding and two independent secondary windings.
13. The energy supply device (10) according to any one of claims 1 to 11, in, The first multi-winding transformer (2) is designed as a four-winding transformer having two primary windings and two independent secondary windings.
14. Energy supply device (10) according to any one of the preceding claims, in, The first AC / DC converter (6), optionally the second AC / DC converter (7) and / or the third AC / DC converter (8) are designed as transistor-based AC / DC converters.
15. An electrolysis device (50), include: an electrolysis unit (20) having an electrolyzer (22) and at least one auxiliary unit (23, 24) for supplying the electrolyzer (22) with chemicals; as well as - An energy supply device (10) according to any of the preceding claims, wherein the DC voltage connection (16) of the energy supply device is connected to the electrolyser (22), and the auxiliary power output (17) of the energy supply device is connected to the at least one auxiliary unit (23, 24) of the electrolysis unit (20).