System and circuit for connecting components of a hydrogen plant to a power source

Abstract

The present disclosure relates to circuits for connecting components of a hydrogen plant to a power grid to power the components in an efficient manner. In one implementation, a power-side alternating current (AC) / direct current (DC) converter can be connected to a source power grid without the need for an isolation transformer by providing a separate bus between the power-side AC / DC converter and the load-side DC / DC converter, instead of a DC bus shared between the converters. Other implementations for connecting components of a hydrogen plant to a power grid may include an adjustable transformer, such as a tap-changing transformer or an autotransformer, for connecting any number of auxiliary loads of the plant to the power grid. The adjustable transformer may accommodate various types of auxiliary load devices for connecting to the power provided simultaneously by the transformer, including both three-phase and one-phase devices.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is related to and claims priority under 35 U.S.C. Section 119(e) of U.S. patent application Ser. No. 63 / 416,290, filed October 14, 2022, entitled "Systems and Circuits for Electrical Balance of Components of a Hydrogen Plant," the entire contents of which are incorporated herein by reference for all purposes.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to systems and methods for controlling hydrogen generation, and more particularly to systems and circuits for connecting components to one or more power sources. [Background technology]

[0003] Hydrogen is a common gas with many industrial uses, such as oil refining, metal processing, food processing, and ammonia production. While hydrogen is abundant and can be produced from a variety of renewable and non-renewable energy sources, its flammability in air makes it difficult to store and transport. As a result, hydrogen is generally not suitable for large-scale production in centralized facilities for subsequent distribution over large geographic areas. Rather, hydrogen is generally used at or near the site of its production. Therefore, many hydrogen production plants consume input resources, such as renewable and non-renewable power sources, that are available at the production location or site. In many cases, this results in powering the hydrogen components from the local power grid. Summary of the Invention [Means for solving the problem]

[0004] One aspect of the present disclosure relates to a hydrogen generation plant including a plurality of alternating current (AC) / direct current (DC) converters, each having an input in electrical communication with a power source and an output, where each of the plurality of AC / DC converters converts an AC power signal from the power source to a DC power signal, and a plurality of DC / DC converters, each having an input electrically connecting to at least one of the plurality of AC / DC converters and an output in electrical communication with a load, wherein a first subset of the plurality of DC / DC converters is connected in parallel to the output of a first AC / DC converter, and a second, different subset of the plurality of DC / DC converters is connected in parallel to the output of a second AC / DC converter to electrically isolate the first AC / DC converter from the second AC / DC converter.

[0005] Another aspect of the present disclosure relates to a method for operating a hydrogen generator. The method may include operations of electrically connecting a plurality of alternating current (AC) / direct current (DC) converters to a power source, electrically connecting a first subset of the plurality of DC / DC converters between an output of a first AC / DC converter of the plurality of AC / DC converters and a load circuit, where the first subset of the plurality of DC / DC converters are in parallel with each other, and electrically connecting a second subset of the plurality of DC / DC converters between an output of a second AC / DC converter of the plurality of AC / DC converters and the load circuit, where the second subset of the plurality of DC / DC converters are in parallel with each other. The method may electrically isolate the first AC / DC converter from the second AC / DC converter.

[0006] Some aspects of the present disclosure relate to a load including a plurality of AC / DC converters, including non-isolated bidirectional AC / DC converters, a plurality of DC / DC converters, including isolated unidirectional DC / DC converters, and / or an electrochemical load, such as at least one electrolyzer.

[0007] Some aspects of the present disclosure relate to a power source that is one of a grid power source or a renewable power source.

[0008] Some further aspects of the present disclosure relate to a transformer comprising a primary winding in electrical communication with a power source and a secondary winding in electrical communication with one or more auxiliary loads. The transformer may be an adjustable transformer comprising one or more taps on the primary or secondary winding to adjust the turns ratio of the transformer. In some other aspects, the transformer may be a solid-state transformer.

[0009] In some aspects of the present disclosure, the one or more auxiliary loads may comprise a three-phase load and a single-phase load, and / or the transformer may be configured to provide power to the three-phase load and the single-phase load. The uninterruptible power supply may also be in electrical communication with the one or more auxiliary loads. [Brief explanation of the drawings]

[0010] The foregoing and other objects, features, and advantages of the present disclosure described herein should be apparent from the following description of specific embodiments of those inventive concepts, as illustrated in the accompanying drawings, which depict only typical embodiments of the disclosure and therefore should not be considered limiting in scope.

[0011] [Figure 1] FIG. 1 illustrates an exemplary environment for hydrogen production according to aspects of the present disclosure.

[0012] [Figure 2A] FIG. 2A illustrates a first exemplary circuit for connecting hydrogen plant components to a power grid according to an aspect of the present disclosure.

[0013] [Figure 2B] FIG. 2B illustrates a second exemplary circuit for connecting hydrogen plant components to a power grid in accordance with aspects of the present disclosure.

[0014] [Figure 3] FIG. 3 illustrates an example circuit for connecting auxiliary load components of a hydrogen plant to a power grid in accordance with aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Detailed Description Various embodiments of the present disclosure are described in detail below. While specific implementations are described, it should be understood that this is done for illustrative purposes only. Those skilled in the art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure. Therefore, the following description and drawings are illustrative and should not be construed as limiting. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description.

[0016] Reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Appearances of the phrase "in one embodiment" in various places within this specification do not necessarily all refer to the same embodiment, nor to separate or alternative embodiments that are mutually exclusive of other embodiments. Furthermore, various features are described that may be exhibited by some embodiments and not by others. Thus, a reference to "one or an embodiment" in this disclosure can be a reference to "the same embodiment or any embodiment," and such a reference means "at least one of the embodiments."

[0017] The terms used herein generally have their ordinary meaning in the art within the context of this disclosure and in the specific context in which each term is used. Alternative terms and synonyms may be used for any one or more of the terms described herein, and no special significance should be placed on whether a term is recited or described herein. In some cases, synonyms for a term are provided. The listing of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any term described herein, is for illustrative purposes only and is not intended to further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the present disclosure is not limited to the various embodiments provided herein.

[0018] Additional features and advantages of the present disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present disclosure will become more fully apparent from the following description and the appended claims, or may be learned by practice of the principles described herein.

[0019] Described herein are systems and circuits for connecting components of a hydrogen plant to a power grid and powering the components in an efficient manner. In one implementation, power-side alternating current (AC) / direct current (DC) converters can be connected to a source power grid without the need for an isolation transformer by providing a separate bus between the power-side AC / DC converter and the load-side DC / DC converter instead of a DC bus shared between the converters. By isolating the DC / DC converters of the grid interface circuit between the power-side AC / DC converters, isolation of the power-side converters can be maintained while providing the required power signal to the load. Because isolation transformers are very large and expensive circuit components, such a configuration is an improvement over previous circuits and may thereby improve the efficiency and cost of connecting hydrogen plant components to a power grid by isolating the outputs of the power-side converters to an isolated subset of the load-side converters.

[0020] Other implementations for connecting hydrogen plant components to the power grid may include adjustable transformers, such as tap-changeable transformers or autotransformers, to connect any number of the plant's auxiliary loads to the power grid. Adjustable transformers can accommodate various types of auxiliary load devices for simultaneous grid connection, including both three-phase and one-phase devices. Also, hydrogen plants do not need to rely on neutral / auxiliary power support. Rather, single-phase loads or devices can be powered by a local neutral generated using a (tap-changeable) transformer / autotransformer. For example, hydrogen plants may be located in various locations around the world and connected to a power grid that is local to the site. However, due to the (tap-changeable) transformer, auxiliary loads can also be powered using any grid voltage. Changes to the grid voltage or primary power architecture would also not require changes to the circuitry downstream of the transformer. In this way, hydrogen plant installations can be easily integrated into the wider grid network because the insulated secondary winding of the transformer provides flexibility for grounding arrangements as per local grid regulations or the designer's choice.

[0021] 1 illustrates an exemplary environment 100 for hydrogen production in accordance with aspects of the present disclosure. Environment 100 may include more or fewer components than those illustrated in FIG. 1, which are included to provide context for the operation and configuration of the plant modeling tool described herein. Additional components and / or configurations of hydrogen production environment 100 are described in more detail below.

[0022] The environment 100 may include a hydrogen plant 106 designed and configured to generate hydrogen. The hydrogen plant 106 may include a system housed in a container, an outdoor-rated cabinet, or multiple systems contained within a plant site. In one implementation, the hydrogen plant 106 may be a clean hydrogen facility. The establishment of such clean hydrogen facilities is in the early stages of the industry, with significant market growth projections that may scale over time to much larger production capacities and more highly integrated conformance with upstream and downstream requirements.

[0023] Clean hydrogen facilities 106 often generate hydrogen through a process known as electrolysis. Generally, electrolysis (i.e., in the context of zero-carbon production of hydrogen) is a rapidly growing and enabling technology that offers a favorable and sustainable alternative to fossil fuels and the resulting environmentally harmful CO2 emissions. Electrolysis is a process that uses electricity to split water into hydrogen and oxygen; this reaction occurs in a unit called an "electrolyzer" 108. Through the electrolysis process, the electrolyzer 108 produces hydrogen gas. Most electrolyzers 108 include an anode and a cathode separated by an electrolyte in the presence of water. As energy, such as direct current (DC) power, is applied, water molecules react at the anode to form oxygen and positively charged hydrogen ions. The hydrogen ions flow through the electrolyte to the cathode, where they combine with electrons to form hydrogen gas. Excess oxygen can be released into the atmosphere or, in some cases, captured or stored for use in other industrial processes or even to provide medical gases. The hydrogen gas can be stored either as a compressed gas or liquefied, and because hydrogen is an energy carrier, it can be used to power trains, buses, trucks, or hydrogen fuel cell electric applications such as data centers. In some cases, the generated hydrogen can be provided to one or more downstream industrial plants 112 for asset manufacturing such as steel, cement, oil, fertilizer, and the like. In one example, liquefied hydrogen can be piped or transported by tanker to the downstream industrial plant 112. In another example, hydrogen gas can be provided to one or more downstream industrial plants 112.

[0024] Electrolyzers 108 can range in size from small devices well suited for distributed hydrogen production on a small scale to large centralized manufacturing facilities that can be directly aligned with renewable or other non-greenhouse gas emission forms of electricity production. Electrolyzers 108 produce clean hydrogen for powering hydrogen fuel cells, feeding industrial processes, or providing a route for producing green chemicals such as fertilizer, renewable natural gas, and methanol. Several electrolyzers 108 can be configured through the connection of various electrolyzer cells, with each cell comprising a small electrolyzer. This configuration is sometimes referred to as an electrolyzer stack. In one implementation, the electrolyzer stack can include multiple cells connected in series in a bipolar design, although other configurations are possible.

[0025] As should be understood, the hydrogen plant 106 may utilize several input resources 110 for the generation of hydrogen. For example, various forms of energy sources (grid electricity, natural gas, wind, solar, hydroelectric, etc.) may be provided to the hydrogen facility 106 for use by the plant components. Other input resources 110, such as water for use by the electrolyzer 108, may also be provided to the hydrogen plant 106 to produce hydrogen.

[0026] Once the hydrogen plant 106 is constructed, control over the plant's various components, systems, programs, and / or sensors may be executed through the on-site controller 114. For example, a supervisory control and data acquisition (SCADA) control system may be integrated with the hydrogen plant 106 to monitor plant conditions and / or control various aspects or parameters of the plant's components. In one particular case, a sensor may be associated with a pipe containing gas generated from the electrolysis process to measure the pressure in the pipe. The sensor may provide a reading or measurement to the on-site controller 114, which may in response adjust one or more valves in the gas piping system to regulate the pressure in the piping system. In general, any adjustable aspect or parameter of the hydrogen plant, a component within the plant, an input resource 110, a sensor, an executable program associated with the plant, or any other aspect of the hydrogen plant 106 may be adjustable by the on-site controller 114. In some cases, the on-site controller 114 may also include an interface through which a plant operator accesses and makes one or more adjustments to the components of the plant 106. In another case, the on-site controller 114 may be configured to automatically adjust parameters or aspects of the hydrogen plant 106 based on input from one or more sensors in the plant or any other source of operational data.

[0027] The environment 100 may also, in some instances, include a remote monitoring system 102 in communication with the hydrogen plant 106 through a network 104 connection. In one example, the remote monitoring system 102 may be in communication with the electrolyzer 108, monitor one or more operating conditions of the electrolyzer, and adjust one or more parameters of the electrolyzer accordingly. The network 104 may be configured to connect the remote monitoring system 102 to one or more communication interface devices of the hydrogen plant 106 and to send and / or receive information between the remote monitoring system and other devices using one or more wired or wireless communication networks or connections. Examples of such networks or connections include, but are not limited to, wired communication via serial or Ethernet in copper or fiber media, or wireless communication over USB, Wi-Fi, Bluetooth, Zigbee mesh networks, or cellular wireless networks. One or more such communication interface devices may be utilized to communicate with the remote monitoring system 102 and / or the hydrogen plant 106 either directly over a point-to-point communication path, over a wide area network (WAN) (e.g., the Internet), over a local area network (LAN), over a cellular (e.g., third generation (3G), fourth generation (4G), fifth generation (5G)) network, or over another communication means.

[0028] As mentioned above, one of the input resources 110 provided to the hydrogen plant 106 can be several types of power sources, such as a non-renewable power source (e.g., a power grid connection) or a renewable power source (e.g., a solar or wind power source). FIG. 2A shows a first exemplary circuit for connecting hydrogen plant components to a power grid in accordance with aspects of the present disclosure. In general, the components of the hydrogen plant 106 are represented in FIG. 2A as loads 202. Thus, the loads 202 may include some or all of the components of the hydrogen plant 106, including the electrolyzer stack 108. In other implementations, the loads 202 may not be specifically associated with the hydrogen plant and may be any electrochemical load capable of receiving a constant current and / or a constant voltage. With respect to the example hydrogen plant 106, the plant may be connected to a power grid 204 (represented in FIG. 2A as a three-phase grid) to power the plant's components. In one implementation, the power grid 204 may provide an alternating current (AC) power signal, such as a three-phase AC signal. However, many components of the load 202 may require a direct current (DC) power signal. Therefore, a series of converter devices may be connected between the power source 204 and the load 202 to provide a DC power signal, among other benefits.

[0029] In the implementation illustrated in FIG. 2A , one or more AC / DC converters 206 (also referred to herein as “power source converters”) may be connected to the power source 204 through an isolation transformer 208. The purpose of the isolation transformer 208 is described in more detail below. The number of power source converters 206 may vary depending on the power requirements of the load 202. The power source converters 206 may be connected in parallel such that the inputs to the AC / DC converters are connected through the isolation transformer 208 and the outputs are connected through an intermediate DC bus 212. The outputs of the power source converters 206 may be connected to one or more DC / DC converters 210 (also referred to herein as “load-side converters”) through the intermediate DC bus 212. The DC / DC converters 210 may also be connected in parallel such that each input is connected to the intermediate DC bus 212 and the output of each DC / DC is connected to the load 202. In one implementation, the power source converters 206 may include one or more non-isolated bidirectional AC / DC converters. In the same or other implementations, the load-side converter 210 may include one or more isolated unidirectional DC / DC converters. Other types of converters are also contemplated for use in the circuit 200 in the same or different configurations.

[0030] As mentioned, the power converters 206 are connected to the power grid 204 via an isolation transformer 208. In one implementation, the isolation transformer 208 may include a primary winding 214 in electrical communication to receive a power signal from the grid 204 and two secondary windings 216 in electrical communication with the two power converters 206. In general, one concern with parallel-connected power converters 206 is that current may circulate between the units. For example, when power converters 206 share input and output connections, current from a first power converter 218 may be provided to a second power converter 220, and vice versa, such that current may circulate between the connected converters. To limit circulating current between the power converters 220, additional passive components, such as large filter inductors and / or current-sharing inductors, may be included in the circuit 200. However, when the power converter ratings of the power converters 206 are large, these solutions become less efficient due to the high cost of the components and potential power losses. Also, due to lower filter inductors in conjunction with the low switching frequency operation required by power devices and converters, circulating currents may be more significant in some situations. Furthermore, hard-switched parallel operation, in which converters are paralleled, may require derating due to nonlinear and parasitic effects that create current-sharing differences. To address these inefficiencies, some circuits may include isolation between converters, which is typically added on the input side. For example, circuit 200 includes an isolation transformer 208 to provide isolation to power converter 206 on the input side. Power frequency isolation transformer 208 enables the use of multiple power AC / DC converters 206 with a common output, such as intermediate DC bus 212. Isolated converters 206 can be treated as individual units delivering power to load 202 without any impact on other power converters 206 connected to the same output 212.

[0031] In some situations, isolation of the power supply converter 206 may be avoided. For example, the use of a high-frequency isolated DC / DC converter 210 to provide high current to the load 202 may be used to avoid problems associated with paralleling AC / DC power supply converters 206. FIG. 2B shows a first exemplary circuit 250 for connecting hydrogen plant components to a power grid in accordance with aspects of the disclosure. Many of the components of the circuit 250 of FIG. 2B are identical to those described above, such as the grid power supply 204 and the load 202. Also, similar to above, the power supply 204 may be connected to one or more power supply converters 252, which may be non-isolated bidirectional AC / DC converters. One or more load-side converters 256 may also be connected between the power supply converter 252 and the load 202. In one particular implementation, the load-side converter 256 may be an isolated bidirectional DC / DC converter. However, in this circuit 250, the outputs of the power supply converters 252 may not be connected by an intermediate DC bus 254. Rather, the output of the power converter 252 may be isolated while still providing the required power signal to the load side converter 256 .

[0032] In this configuration, the load-side converters 256 may be divided among the power converters 252 such that the output from each power converter is provided to a subset of the load-side converters. For example, power converter 258 may provide a converted power signal to load-side converter 264, while power converter 260 may provide a converted power signal to load-side converter 262. In this manner, the outputs of the power converters 252 may not be shared on a common intermediate DC bus, but instead are connected to one or more load-side converters 256 across separate intermediate DC buses 254. Through the use of separate DC buses 254 to provide converted power signals to the load-side converters 256, isolation of the power converters 252 is maintained without the need for isolation transformers. Rather, each of the power converters 252 may be directly connected to the power grid 204. Because isolation transformers are very large and expensive components of the circuit, this configuration is an improvement over previous circuits and may improve the efficiency and cost of connecting hydrogen plant components to the power grid 204 by isolating the output of the power converters 252 to a subset of the load side converters 256.

[0033] Additionally, the configuration of circuit 250 can be scaled based on the power requirements of the hydrogen plant components without reliance on isolation transformer 208. For example, P DC-DC Assume the power rating of the load-side DC / DC converters 256 and the number (n) of such converters in each block. AC-DC Assume a power rating of power supply AC / DC converters 252 and a number (m) of such converters. For example, in circuit 250 of FIG. 2B, n=2 because each converter block contains two DC / DC load-side converters for one AC / DC power converter. In this case, P AC / DC >=n*P DC-DC is.

[0034] The number m of power converters 252 needed for a circuit can be calculated based on the required load power. For example, P LOADFor a power rating of a load in m, the number of AC / DC power converters 252 is determined by the equation m=P LOAD / P AC-DC Therefore, for a 300 kW power delivery application, assuming the number of load side converters 256 is two per power converter, seven AC / DC power converters 252 may be utilized in the circuit. For a 400 kW power delivery application, again assuming the number of load side converters 256 is two per power converter, nine AC / DC power converters 252 may be utilized in the circuit. In this manner, the configuration of power converters 252 is highly scalable based on the power rating requirements of the loads 202 to adjust for all types of loads and components of the hydrogen plant.

[0035] Other components of the hydrogen plant 106 may also be connected to grid power but may not require the high current or high voltage of the load 202 described above. For example, one or more auxiliary loads (pumps, fans, telemetry devices, etc.) may be used within the hydrogen plant 106 and powered from the power grid 204. However, such auxiliary components may be decoupled from the main load (plant load 202) and the large power converter described above. Decoupling the auxiliary components from the large power converter provides a more efficient manner for powering such devices. FIG. 3 shows an example circuit 300 for connecting auxiliary load components 312 of a hydrogen plant to the power grid in accordance with aspects of the present disclosure. In general, the auxiliary load devices 312 may require lower current and / or voltage to operate compared to the plant load devices 202. However, the auxiliary load devices 312 may require three-phase power or one-phase power. Therefore, the circuit 300 of FIG. 3 may include one or more components for providing power in three-phase or one-phase power. Additionally, circuit 300 may include components that provide connection to various types of grid power 204. For example, the hydrogen plant 106 described above may be located in various locations around the world and connected to power grids that are local to the site. Power grids around the world provide different levels of power, such as the United States providing a 120-volt AC power signal, some European countries providing a 230-volt AC power signal, and Japan providing a 100-volt AC power signal. Therefore, the components of connection circuit 300 of FIG. 3 may be selected and / or configured so that connection can be made to various types of power grids.

[0036] The circuit 300 may include several components described above, such as a connection to the power grid 204, one or more AC / DC converters 206, one or more DC / DC converters 210, and a plant load 202, which may include one or more electrolyzer devices. Additionally, one or more auxiliary load devices 312 may receive power from the power grid 204. A transformer 304 may be connected to the power grid 204 to provide a power signal to the auxiliary load 312 with the flexibility to connect to various types of grid power signals. In one implementation, the transformer 304 may be a tap-changeable transformer, such as an isolation or auto-type transformer, that is configurable for various grid sources to bring the grid voltage level into a suitable range for the auxiliary load changer 312. For example, the tap-changeable transformer 304 may include a mechanism to allow a variable turns ratio to be selected, perhaps through a mechanical switching device. Other embodiments may utilize an automatic system to adjust the turns ratio of the transformer 304 using a fixed tap and / or multiple taps. The tap changer may connect to any number of access points on the transformer along either the primary or secondary side to adjust the device's turns ratio and transformation of the input power signal to the output power signal. In other implementations, the transformer 304 may have fixed primary and / or secondary windings with insulation, or may have adjustable taps on one or both windings. In another implementation, the transformer 304 may be a solid-state transformer with one or more power electronic components that provide the same functionality of the tap-changeable transformer described above. Such solid-state transformers may include high-frequency insulation. Furthermore, the transformer 304 may be configured to provide output power from the transformer 304 on each of the three phases of the power signal for powering each of the auxiliary load devices 312. In one particular implementation, the transformer 304 may connect to the power grid 204 over a three-wire connection and output a four-wire connection.

[0037] In addition to powering the auxiliary load 312 from the local power grid 204, the circuit 300 may include components to ensure power to the device if grid power is lost. In particular, the circuit 300 may include an uninterruptible power supply (UPS) 306 connected to the auxiliary load 312, which may store power and provide it to the auxiliary load when needed. The UPS 306 may, in some cases, receive stored power from a transformer 304 and / or a battery 308 connected to the UPS. In other implementations, the UPS 306 may be connected to a continuous generator (such as a fuel cell generator, a photovoltaic generator, a piston-type engine generator, etc.) connected in parallel with or in place of the battery 308 to provide power to the UPS. A bypass switch (not shown) may be included to alternately connect the auxiliary load 312 to the transformer 304 or the UPS 306 based on the desired power source. Generally, the UPS 306 operates in standby mode until a loss of power from the grid source 204 is detected. Upon detection, the switch 310 may be opened and power may be provided from the UPS 306 to the auxiliary load 312. In this manner, power may be continuously provided to the auxiliary load 312 even during a power loss of the grid source 204 or an outage of other components of the hydrogen plant.

[0038] 3 provides power to auxiliary loads 312, which may enable them to operate without grid power 204 for data logging, freeze protection, hazard mitigation, and similar reasons. The auxiliary leg of circuit 300 provides the power needed for auxiliary loads 312 out of scale, five to ten times greater than the plant load 202 power. Furthermore, proper sizing and design of the power channels for these different needs improves the efficiency of circuit 300. For example, providing a UPS 306 downstream of transformer 304 provides fault-tolerant functionality to the circuit.

[0039] As described above, the circuit 300 may operate to provide power on each phase of the power signal. This allows various types of auxiliary load devices 312 to connect to the power provided by the transformer 304, such as three-phase or one-phase devices. Furthermore, these lower-voltage devices may generally have high-frequency, high-efficiency configurations to improve the operation of the circuit 300 and the hydrogen plant 106. In one implementation, the devices of the circuit 300 may include gallium nitride (GaN)-type components and designs to improve the functionality of the circuit 300. In this way, the entire hydrogen plant does not rely on neutral / auxiliary power support. Rather, single-phase loads or devices can be powered by a local neutral generated using the (tap-changeable) transformer / autotransformer 304. Furthermore, due to the (tap-changeable) transformer 304, the auxiliary loads 312 can operate with any grid voltage. Changes to the grid voltage or the main power architecture would not require changes to the circuit 300 downstream of the transformer 304. In this way, the installation of the hydrogen plant can be easily incorporated into a wide grid network, for example, corner grounding in Japan, because the isolated secondary winding of the transformer 304 provides the flexibility to have a grounding scheme as per local grid regulations or designer's choice.

[0040] In some cases, one or more auxiliary load devices 312 may be powered directly from the battery 308 or other power source, such as the sustained generators listed above. For example, the battery 308 or generator may power auxiliary devices with built-in energy storage at lower voltage levels (such as 24V). Power may be provided to these low-voltage auxiliary devices via a simple diode circuit or other power interface circuit. Additionally, elements of the battery 308, UPS 306, and / or generator may be interlocked with one or more safety features of the plant load 202 to prevent the power source from being enabled until a permissive signal is acknowledged by the safety logic of the control computer or embedded controller (such as confirmation of successful ventilation exhaust). Exemplary Embodiments

[0041] Embodiment 1: A hydrogen generation plant, comprising: a plurality of alternating current (AC) / direct current (DC) converters, each having an input in electrical communication with a power source and an output, each of the plurality of AC / DC converters converting an AC power signal from the power source to a DC power signal; a plurality of AC / DC converters, each having an input electrically connected to at least one of the plurality of AC / DC converters and an output in electrical communication with a load; a first subset of the plurality of DC / DC converters connected in parallel to the output of a first AC / DC converter, and a second distinct subset of the plurality of DC / DC converters connected in parallel to the output of a second AC / DC converter, electrically isolating the first AC / DC converter from the second AC / DC converter.

[0042] Embodiment 2: The hydrogen generation plant of embodiment 1, wherein the plurality of AC / DC converters includes a non-isolated bidirectional AC / DC converter.

[0043] Embodiment 3: The hydrogen generation plant according to embodiment 1 or embodiment 2, wherein the plurality of DC / DC converters includes an isolated unidirectional DC / DC converter.

[0044] Embodiment 4: The hydrogen generation plant of any one of embodiments 1-3, wherein the load is an electrochemical load.

[0045] Embodiment 5: The hydrogen generation plant of any one of embodiments 1-4, wherein the load comprises at least one electrolyzer.

[0046] Embodiment 6: The hydrogen generation plant of any one of embodiments 1-5, wherein the power source is one of a grid power source or a renewable power source.

[0047] Embodiment 7: The hydrogen generation plant of any one of embodiments 1-6, further comprising a transformer having a primary winding in electrical communication with a power source and a secondary winding in electrical communication with one or more auxiliary loads.

[0048] Embodiment 8: A hydrogen generation plant as described in embodiment 7, wherein the transformer is an adjustable transformer with one or more taps on the primary or secondary winding to adjust the turns ratio of the transformer.

[0049] Embodiment 9: The hydrogen generation plant of embodiment 7 or embodiment 8, wherein the transformer is a solid-state transformer.

[0050] Embodiment 10: The hydrogen generation plant of any one of embodiments 7-9, wherein the one or more auxiliary loads include a three-phase load and a single-phase load.

[0051] Embodiment 11: The hydrogen generation plant of embodiment 10, wherein the transformer is configured to provide power to a three-phase load and a single-phase load.

[0052] Embodiment 12: The hydrogen generation plant of any one of embodiments 7-11, further comprising an uninterruptible power supply in electrical communication with one or more auxiliary loads.

[0053] Embodiment 13: A method for operating a hydrogen generator, comprising: electrically connecting a plurality of alternating current (AC) to direct current (DC) converters to a power source; electrically connecting a first subset of the plurality of DC / DC converters between an output of a first AC / DC converter of the plurality of AC / DC converters and a load circuit, the first subset of the plurality of DC / DC converters being in parallel with each other; electrically connecting a second subset of the plurality of DC / DC converters between an output of a second AC / DC converter of the plurality of AC / DC converters and a load circuit, the second subset of the plurality of DC / DC converters being in parallel with each other; wherein the first AC / DC converter is electrically isolated from the second AC / DC converter.

[0054] Embodiment 14: The method of embodiment 13, wherein the plurality of AC / DC converters includes a non-isolated bidirectional AC / DC converter.

[0055] Embodiment 15: The method of embodiment 13 or embodiment 14, wherein the plurality of DC / DC converters includes an isolated unidirectional DC / DC converter.

[0056] Embodiment 16: The method of any one of embodiments 13-15, wherein the load comprises at least one electrolytic cell.

[0057] Embodiment 17: The method of any one of embodiments 13-16, further comprising electrically connecting one or more auxiliary loads to the power source via a transformer.

[0058] Embodiment 18: The method of embodiment 17, wherein the one or more auxiliary loads include a three-phase load and a single-phase load.

[0059] Embodiment 19: The method of embodiment 17 or embodiment 18, wherein the transformer is configured to provide power to a three-phase load and a single-phase load.

[0060] Embodiment 20: A method according to any one of embodiments 17-19, further comprising electrically connecting a bypass switch between one or more auxiliary loads and an uninterruptible power supply (UPS), the bypass switch switching power to the one or more auxiliary loads from the power source to the UPS in response to a loss of power by the power source.

[0061] Embodiments of the present disclosure include various steps described herein. The steps may be performed by hardware components or embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, the steps may be performed by a combination of hardware, software, and / or firmware.

[0062] Various embodiments of the present disclosure are described in detail below. While specific implementations are described, it should be understood that this is done for illustrative purposes only. Those skilled in the art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure. Therefore, the following description and drawings are illustrative and should not be construed as limiting. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, in certain instances, well-known or conventional details are not described to avoid obscuring the description. A reference to "one or an embodiment" in this disclosure can be a reference to "the same embodiment or any embodiment," and such a reference means "at least one of the embodiments."

[0063] Reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Appearances of the phrase "in one embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, nor do they refer to separate or alternative embodiments that are mutually exclusive of other embodiments. Additionally, various features are described that may be exhibited by some embodiments and not by others.

[0064] The terms used herein generally have their ordinary meaning in the art, within the context of this disclosure and in the specific context in which each term is used. Alternative terms and synonyms may be used for any one or more of the terms described herein, and no particular significance should be placed on whether a term is recited or described herein. In some cases, synonyms for a term are provided. The listing of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any term described herein, is merely illustrative and is not intended to further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the present disclosure is not limited to the various embodiments provided herein.

[0065] Without intending to limit the scope of the present disclosure, examples of instruments, devices, methods and their related results according to embodiments of the present disclosure are provided below. It should be noted that titles or subtitles may be used in the examples for the convenience of the reader and are not intended to limit the scope of the present disclosure in any way. Unless otherwise defined, technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present disclosure pertains. In case of conflict, the present document, including definitions, will control.

[0066] (Item 1) 1. A hydrogen generation plant comprising: a plurality of alternating current (AC) / direct current (DC) converters, each having an input and an output in electrical communication with a power source, each of the plurality of AC / DC converters converting an AC power signal from the power source into a DC power signal; a plurality of DC / DC converters, each having an input electrically connected to at least one of the plurality of AC / DC converters and an output in electrical communication with a load; a first subset of the plurality of DC / DC converters connected in parallel to an output of a first AC / DC converter and a second, different subset of the plurality of DC / DC converters connected in parallel to an output of a second AC / DC converter, electrically isolating the first AC / DC converter from the second AC / DC converter. (Item 2) Item 2. The hydrogen generation plant according to item 1, wherein the plurality of AC / DC converters include a non-isolated bidirectional AC / DC converter. (Item 3) Item 2. The hydrogen generation plant according to item 1, wherein the plurality of DC / DC converters include isolated unidirectional DC / DC converters. (Item 4) 2. The hydrogen generation plant according to item 1, wherein the load is an electrochemical load. (Item 5) Item 2. The hydrogen generation plant according to item 1, wherein the load comprises at least one electrolyzer. (Item 6) Item 1. The hydrogen generation plant according to item 1, wherein the power source is one of a grid power source or a renewable power source. (Item 7) Item 10. The hydrogen generation plant of item 1, further comprising a transformer having a primary winding in electrical communication with the power source and a secondary winding in electrical communication with one or more auxiliary loads. (Item 8) 8. The hydrogen generation plant according to item 7, wherein the transformer is an adjustable transformer having one or more taps on the primary winding or the secondary winding to adjust the turns ratio of the transformer. (Item 9) 8. The hydrogen generation plant according to item 7, wherein the transformer is a solid-state transformer. (Item 10) 8. The hydrogen generation plant according to claim 7, wherein the one or more auxiliary loads include a three-phase load and a single-phase load. (Item 11) Item 11. The hydrogen generation plant according to item 10, wherein the transformer is configured to provide power to the three-phase load and the single-phase load. (Item 12) 8. The hydrogen generation plant of claim 7, further comprising an uninterruptible power supply in electrical communication with the one or more auxiliary loads. (Item 13) 1. A method for operating a hydrogen generator, comprising: electrically connecting a plurality of alternating current (AC) to direct current (DC) converters to a power source; electrically connecting a first subset of the plurality of DC / DC converters between an output of a first AC / DC converter of the plurality of AC / DC converters and a load circuit, the first subset of the plurality of DC / DC converters being in parallel with each other; electrically connecting a second subset of the plurality of DC / DC converters between an output of a second AC / DC converter of the plurality of AC / DC converters and the load circuit, the second subset of the plurality of DC / DC converters being in parallel with each other; wherein the first AC / DC converter is electrically isolated from the second AC / DC converter. (Item 14) Item 14. The method of item 13, wherein the plurality of AC / DC converters includes a non-isolated bidirectional AC / DC converter. (Item 15) Item 14. The method of item 13, wherein the plurality of DC / DC converters includes isolated unidirectional DC / DC converters. (Item 16) Item 14. The method of claim 13, wherein the load comprises at least one electrolytic cell. (Item 17) Item 14. The method of item 13, further comprising electrically connecting one or more auxiliary loads to the power source via a transformer. (Item 18) Item 18. The method of item 17, wherein the one or more auxiliary loads include a three-phase load and a single-phase load. (Item 19) Item 18. The method of item 17, wherein the transformer is configured to provide power to the three-phase load and the single-phase load. (Item 20) Item 18. The method of item 17, further comprising electrically connecting a bypass switch between the one or more auxiliary loads and an uninterruptible power supply (UPS), the bypass switch switching power to the one or more auxiliary loads from the power source to the UPS in response to a loss of power by the power source.

Claims

1. 1. A hydrogen generation plant comprising: a plurality of non-isolated bidirectional alternating current (AC) to direct current (DC) converters, each having an input and an output in electrical communication with a power source, each of the plurality of AC / DC converters converting an AC power signal from the power source into a DC power signal; a plurality of isolated unidirectional DC / DC converters, each having an input electrically connected to at least one of the plurality of AC / DC converters and an output in electrical communication with a load; a first subset of the plurality of DC / DC converters connected in parallel to an output of a first AC / DC converter and a second, different subset of the plurality of DC / DC converters connected in parallel to an output of a second AC / DC converter, electrically isolating the first AC / DC converter from the second AC / DC converter.

2. The hydrogen generation plant of claim 1 , wherein the load is an electrochemical load.

3. The hydrogen generation plant of claim 1 , wherein the load comprises at least one electrolyzer.

4. 10. The hydrogen generation plant of claim 1, wherein the power source is one of a grid power source or a renewable power source.

5. The hydrogen generation plant of claim 1 further comprising a transformer having a primary winding in electrical communication with the power source and a secondary winding in electrical communication with one or more auxiliary loads.

6. 6. The hydrogen generation plant of claim 5, wherein the transformer is an adjustable transformer with one or more taps on the primary or secondary windings to adjust the turns ratio of the transformer.

7. 6. The hydrogen generation plant of claim 5, wherein the transformer is a solid-state transformer.

8. The hydrogen generation plant of claim 5 , wherein the one or more auxiliary loads include a three-phase load and a single-phase load.

9. The hydrogen generation plant of claim 8 , wherein the transformer is configured to provide power to the three-phase load and the single-phase load.

10. The hydrogen generation plant of claim 5 further comprising an uninterruptible power supply in electrical communication with the one or more auxiliary loads.

11. 1. A method for operating a hydrogen generator, comprising: electrically connecting a plurality of non-isolated bidirectional alternating current (AC) to direct current (DC) converters to a power source; electrically connecting a first subset of a plurality of isolated unidirectional DC / DC converters between an output of a first AC / DC converter of the plurality of AC / DC converters and a load circuit, the first subset of the plurality of DC / DC converters being in parallel with each other; electrically connecting a second subset of the plurality of DC / DC converters between an output of a second AC / DC converter of the plurality of AC / DC converters and the load circuit, the second subset of the plurality of DC / DC converters being in parallel with each other; wherein the first AC / DC converter is electrically isolated from the second AC / DC converter.

12. The method of claim 11 , wherein the load comprises at least one electrolytic cell.

13. The method of claim 11 , further comprising electrically connecting one or more auxiliary loads to the power source via a transformer.

14. The method of claim 13 , wherein the one or more auxiliary loads include a three-phase load and a single-phase load.

15. The method of claim 13 , wherein the transformer is configured to provide power to the three-phase load and the single-phase load.

16. 14. The method of claim 13, further comprising electrically connecting a bypass switch between the one or more auxiliary loads and an uninterruptible power supply (UPS), the bypass switch switching power to the one or more auxiliary loads from the power source to the UPS in response to a loss of power by the power source.

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