System for generating hydrogen

Abstract

A system (1) for generating hydrogen comprises a reaction vessel (101) comprising an aqueous solution (102) and a cathode (105) and an anode (107), the cathode and the anode each being at least partially positioned in the reaction vessel (101). The system (1) comprises a first and a second ultrasonic transducer (215-220) emitting ultrasonic waves in the directions of the cathode (105) and the anode (107), respectively. Each ultrasonic transducer (215-220) is driven by a respective transducer driver (202) to optimize the operation of the system (1) for generating hydrogen by ultrasonic electrolysis.

Description

Background Art

[0001] The present invention relates to systems for generating hydrogen gas. More particularly, the present invention relates to systems for generating hydrogen gas from non-carbonaceous sources using aqueous solution electrolysis in combination with ultrasound.

[0002] Today, most hydrogen production in the United States (and other countries) uses natural gas reforming, which increases CO 2 and methane emissions, and almost all hydrogen use is in industrial settings. U.S. Department of Energy's Hydrogen Shot TM The plan addresses the challenge of clean hydrogen production, seeking to reduce the cost of clean hydrogen by 80% to $1 per kilogram within a decade. Clean hydrogen is essential to reaching net zero by 2050. However, more research and development in clean hydrogen is needed to achieve that goal.

[0003] With the current trend of using environmentally friendly energy sources to reduce carbon footprint in every electricity consuming industry, switching to green energy production is the focus of various energy production industries, academic institutions and even governments. However, renewable green energy production itself comes with a host of challenges. The innovative and educational ideas presented in this article are potential solutions to some of the challenges within the energy industry.

[0004] Currently, the world relies heavily on fossil fuels to meet its energy needs, and reducing the carbon footprint will require the use of alternative energy sources to these fossil fuels.

[0005] One of the alternatives to fossil fuels is hydrogen, however, its production, storage, transportation and consumption present various complexities.

[0006] Hydrogen can be produced by splitting water molecules into hydrogen and oxygen. It is collected on separate electrodes through the process of electrolysis. Electrolysis is a process that involves passing an electric current through an aqueous solution, causing a chemical reaction. The process separates the solution into its constituent elements or produces a desired chemical product.

[0007] Two electrodes are immersed in an aqueous solution, such as an electrolyte solution (a solution containing a conductive substance). The electrodes are usually made of an inert material (graphite, platinum, stainless steel, etc.) connected to a power source, such as a DC current source. The elements in the solution are split into positive and negative ions, which can be collected at the electrodes; positive ions accumulate at the negative electrode (cathode), and negative ions accumulate at the positive electrode (anode). The electrolysis of water results in a decomposition reaction in which individual water molecules break down into hydrogen and oxygen ions.

[0008] An oxidation reaction occurs at the anode. The oxidation "half-reaction" is:

[0009]

[0010] A reduction reaction occurs at the cathode. The reduction "half-reaction" is:

[0011]

[0012] Therefore, the reaction for water electrolysis is:

[0013]

[0014] Hydrogen ions (H+) collect at the cathode (-), while hydroxide ions (OH-) collect at the anode (+). 2 O) to produce hydrogen (H 2 ) and oxygen (O 2 ). An ionic solution (electrolyte), although not required, is preferably dissolved in the water to facilitate the electrolysis reaction. An electrolyte is a solution that is conductive and contains ions. The composition of the electrolyte depends on the specific application of the electrolysis process.

[0015] In conventional water electrolysis, the electrolyte used is a solution of a salt or acid dissolved in water. In conventional water electrolysis, the electrolyte may be a dilute sulfuric acid solution (H 2 SO 4 ) or an aqueous solution of sodium hydroxide (NaOH).

[0016] Because the anode is connected to the positive terminal of the power supply, the anode is positively charged. On the contrary, because the cathode is connected to the negative terminal of the power supply, the cathode is negatively charged. An electric field is formed between the anode and the cathode in the direction from the anode to the cathode.

[0017] Inside the electric field, positive charges experience a force that accelerates them in the direction of the electric field, and negative charges experience a force that accelerates them in the opposite direction of the electric field. These forces cause ions in the aqueous solution to flow toward the anode and cathode, and inherently accelerate the electrolysis reaction.

[0018] For example, in a sodium hydroxide (NaOH) solution, positively charged sodium ions (Na + ) will experience a force that accelerates the positive ions toward the cathode, while the hydroxide (OH - ) negative ions will be accelerated toward the anode. When in contact with the anode, the hydroxide ions are oxidized by releasing additional electrons, causing electrons to flow through the external circuit and resulting in the generation and release of oxygen (O) at the anode. 2 At the cathode, H+ ions replace sodium ions (Na + ) discharge because H+ ions are easier to discharge than sodium ions. Therefore, water molecule reduction is the more favored reaction, and H+ ions are reduced to hydrogen gas (H 2 ).

[0019] Within a water molecule, covalent bonds are formed by sharing electrons between atoms. Each water molecule consists of two hydrogen atoms, covalently bonded individually to oxygen atoms. These covalent bonds involve sharing of electrons between oxygen and hydrogen atoms, resulting in a stable molecular structure. Figure 1 In the diagram, the polar covalent bonds between the oxygen and hydrogen atoms in each water molecule are shown as solid lines.

[0020] The energy stored within a covalent bond, called bond dissociation energy, represents the energy required to break the bond and separate the atoms. For a water molecule, the bond dissociation energy for each OH covalent bond is approximately 460 kilojoules per mole (kJ / mol), indicating the strength of the bond and the energy required to weaken / break the bond.

[0021] In order to 2 O) into its constituent elements, the bond dissociation energy for each OH bond is about 460 kJ / mol. Since water has two OH bonds, the total energy required to decompose a water molecule into hydrogen and oxygen is about 920 kJ / mol. One mole of water weighs 18 grams.

[0022] On the other hand, hydrogen bonds form between partially positive hydrogen atoms of one water molecule and partially negative oxygen atoms of an adjacent water molecule. Due to the high electronegativity of oxygen, the oxygen atom attracts the shared electrons in the OH bond, creating a partial negative charge on the oxygen atom and a partial positive charge on the hydrogen atom. This polarity allows the water molecules to form high surface tension and cohesion. Hydrogen bonds between water molecules are Figure 1 Indicated by dotted lines.

[0023] The energy required to break hydrogen bonds in water can range from 5 kJ / mol to 30 kJ / mol. This energy requirement is significantly lower than the approximately 460 kJ / mol required to break covalent OH bonds within water molecules.

[0024] Although conventional production of hydrogen is a simple theoretical process, it has historically been slow and energy intensive, and despite being a clean-burning fuel, has made the product (hydrogen) expensive and unsustainable as an economically viable alternative to fossil fuels. Existing electrolysis processes consume large amounts of energy in splitting water into hydrogen and oxygen ions. Methods that reduce energy consumption are needed to achieve sustainable and consistent availability of hydrogen as a fuel.

[0025] In some electrolysis applications, ultrasound can be used to enhance the process. This is called ultrasonic electrolysis or ultrasound-assisted electrolysis. Although ultrasound improves electrolysis efficiency, conventional systems using ultrasound are generally not optimized to take into account the different temperatures and properties of aqueous solutions.

[0026] In addition, the electrodes used in the water electrolysis process degrade as the reaction proceeds, requiring downtime when replacing the electrodes and leading to frequent replacement of metal electrodes. This increases the overall operating cost of the process, making it economically unviable. Deterioration of the electrode material also results in an increase in the energy consumed to produce a similar amount of hydrogen compared to new electrodes.

[0027] Therefore, there is a need for improvement in materials in terms of durability of components used in the hydrogen electrolysis process to withstand harsh electrolysis conditions in order to reduce the cost and energy required to achieve a sustainable and stable supply of hydrogen as a fuel.

[0028]

[0006] Therefore, there is a need in the art for a more environmentally friendly system for generating hydrogen that attempts to address at least some of the problems described herein. Summary of the invention

[0029] The invention provides a system as claimed in claims 1, 2 and 19. The invention also provides preferred embodiments as claimed in the dependent claims.

[0030] The system of the examples of the present disclosure has significant environmental benefits by reducing the energy required to generate hydrogen. This in turn reduces the cost of producing hydrogen.

[0031] An additional benefit of the system of the examples of the present disclosure is that the system can directly use wastewater or seawater as the aqueous solution without the need to desalinate the seawater. This avoids the need for energy-intensive and expensive desalination. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order that the present disclosure may be more readily understood, preferred embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0033] Figure 1 is a diagram showing the bonds between water molecules in an aqueous solution;

[0034] Figure 2 are schematic diagrams of systems of some examples of the present disclosure; Figure 3 are schematic diagrams of some exemplary reaction vessels and system components of the present disclosure;

[0035] Figure 4 are schematic diagrams of some exemplary reaction vessels and system components of the present disclosure;

[0036] Figure 5 are schematic diagrams of some exemplary reaction vessels and system components of the present disclosure;

[0037] Figure 6 are schematic diagrams of some exemplary reaction vessels and system components of the present disclosure;

[0038] Figure 7is a schematic diagram of placing an ultrasound transducer around an electrode in a system of some examples of the present disclosure;

[0039] Figure 8 is a schematic diagram of placing an ultrasound transducer around an electrode in a system of some examples of the present disclosure;

[0040] Fig. 9 are diagrammatic views of a transducer holder and an ultrasound transducer of a system of some examples of the present disclosure;

[0041] Fig.10 are diagrammatic views of some exemplary reaction vessels and system components of the present disclosure;

[0042] Fig.11 A table showing the relationship between the component sizes of the system of some examples of the present disclosure;

[0043] Fig.12 is a diagrammatic view of a membrane electrode assembly of a system of some examples of the present disclosure;

[0044] Fig.13 are diagrammatic perspective views of systems of some examples of the present disclosure;

[0045] Fig.14 yes Fig.13 A diagrammatic side view of a system;

[0046] Fig.15 yes Fig.13 A cross-sectional side view of a system;

[0047] Fig.16 yes Fig.13 a cross-sectional view of a portion of a system;

[0048] Fig.17 are diagrammatic perspective views of array systems of some examples of the present disclosure;

[0049] Fig.18 is a schematic diagram of an integrated circuit arrangement of the present disclosure;

[0050] Fig.19 is a schematic diagram of an integrated circuit of the present disclosure;

[0051] Fig. 20 is a schematic diagram of a pulse width modulation generator of the present disclosure;

[0052] Fig.21 is a timing diagram of an example of the present disclosure;

[0053] Fig. 22 is a timing diagram of an example of the present disclosure;

[0054] Fig.23 is a table showing port functions of an example of the present disclosure;

[0055] Fig.24 is a schematic diagram of an integrated circuit of the present disclosure;

[0056] Fig.25 is a circuit diagram of an H-bridge of an example of the present disclosure;

[0057] Fig.26 is a circuit diagram of an example current sensing arrangement of the present disclosure;

[0058] Fig. 27 is a circuit diagram of an H-bridge of an example of the present disclosure;

[0059] Fig.28 It is shown in Fig.25 A graph of the voltage during the operating phase of the H-bridge;

[0060] Fig.29 It is shown in Fig.25 A graph of the voltage during the operating phase of the H-bridge;

[0061] Fig.30 The ultrasonic transducer is shown in Fig.25 A graph of voltage and current at the terminals of the ultrasonic transducer when the H-bridge is driven; and

[0062] Fig.31 is a schematic diagram showing connections between integrated circuits of the present disclosure. DETAILED DESCRIPTION

[0063] When read in conjunction with the accompanying drawings, various aspects of the present disclosure can be best understood from the following detailed description. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, for clarity of discussion, the sizes of various features may be arbitrarily increased or decreased.

[0064] The following disclosure provides many different embodiments or examples for realizing the different features of the provided subject matter. To simplify the present disclosure, specific examples of components, concentrations, applications and arrangements will be described below. Of course, these are merely examples and are not intended to be limiting. For example, the attachment of the first feature and the second feature in the following description may include an embodiment in which the first feature and the second feature are attached in a direct contact manner, and may also include an embodiment in which an additional feature may be positioned between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may repeat figure numerals and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself determine the relationship between the various embodiments and / or configurations discussed.

[0065] The following disclosure describes representative examples. Each example can be considered an embodiment, and any reference to an "example" in this disclosure can be changed to an "embodiment."

[0066] Refer to the attached figure Figure 2 , a system 1 for generating hydrogen includes a main controller 2. The main controller 2 coordinates the operation of the components in the system 1 to optimize the operation of the system 1 for generating hydrogen. In some examples, the main controller 2 includes a computing device having a processor and a non-transitory storage for executing instructions.

[0067] Refer to the attached figure Figure 3 , the system 1 of the example of the present disclosure includes a reaction vessel 101 containing an aqueous solution 102 .

[0068] In some examples of the present disclosure, the aqueous solution 102 is water. In other examples of the present disclosure, the aqueous solution 102 is an electrolyte solution containing an electrolyte (such as sodium hydroxide). In another example of the present disclosure, the aqueous solution 102 is wastewater or seawater. If seawater is used, the seawater does not need to be desalinated for use in the system of the examples of the present disclosure. However, when seawater is used as an electrolyte in the electrolysis process, other chemicals may be added to accelerate the hydrogen production rate according to the characteristics of the seawater.

[0069] In some examples, sodium hydroxide (NaOH) may be added to increase the pH of the seawater. This promotes the formation of hydroxide ions, which enhances the extraction of hydrogen during electrolysis. In other examples, optional additives such as sodium hydroxide or other chemicals are omitted.

[0070] In this example, the reaction vessel 101 is cylindrical and includes a curved sidewall 103, however, other shapes and configurations of reaction vessels suitable for the intended purpose are contemplated and within the scope of the present invention. The reaction vessel 101 includes a flat or planar base 104. In this example, the base 104 is circular and has a diameter that is equal to or substantially equal to the height of the sidewall 103. In this example, the reaction vessel 101 thus has a 1:1 aspect ratio.

[0071] The shape of the reaction vessel 101 of this example promotes the formation and collapse of cavitation bubbles during electrolysis while effectively mixing the aqueous solution 102 .

[0072] The shape of the reaction vessel 101 affects the efficiency and effectiveness of the system for electrolysis. The optimal shape of the reaction vessel 101 depends on various factors, the characteristics of the aqueous solution 102, and the geometry of the electrodes. In some examples, the optimal shape of the reaction vessel 101 is a cylinder with a diameter-to-height ratio of 1:1.

[0073] The benefits of using a cylindrical reaction vessel with a 1:1 aspect ratio include:

[0074] Reduced current path length :

[0075] In a cylindrical reaction vessel with a 1:1 aspect ratio, the distance between the electrodes is minimized. This shorter current path length reduces the resistance encountered by ions during their migration toward the electrodes, improving mass transfer efficiency and electrolysis rate.

[0076] Effective bubble release :

[0077] The cylindrical shape facilitates the release and removal of bubbles generated during electrolysis. The vertical orientation of the cylinder allows bubbles to naturally rise to the top, minimizing the possibility of bubble accumulation and clogging near the electrodes. This promotes continuous electrolysis and helps maintain stable and efficient operation.

[0078] Scalability :

[0079] Cylindrical vessels with a ratio of 1:1 are relatively easy to manufacture. Cylindrical vessels can be easily realized in various sizes to accommodate larger electrolysis setups. In addition, the cylindrical shape simplifies the design and construction of the support structure, ensuring practicality and ease of operation.

[0080] The reaction vessel 101 is provided with a cathode 105 at least partially positioned within the reaction vessel 101. A portion of the cathode 105 has an outer surface 106 immersed in and in electrical contact with the aqueous solution 102 to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode 105.

[0081] The reaction vessel 101 is provided with an anode 107 at least partially positioned within the reaction vessel 101. A portion of the anode 107 has an outer surface 108 immersed in and in electrical contact with the aqueous solution 102 to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen at the anode 107.

[0082] Cathode 105 and anode 107 are positioned in reaction vessel 101 to be spaced apart from each other and from sidewall 103. In this example, cathode 105 and anode 107 are parallel or generally parallel to sidewall 103, so that cathode 105 and anode 107 stand vertically in reaction vessel 101.

[0083] Cathode 105 and anode 107 are configured to receive power from a power source (not shown). In this example, cathode 105 is electrically coupled to a negative terminal of a power source, such as a DC power source. Anode 107 is electrically coupled to a positive terminal of the power source. In this example, the power source is a battery, but in other examples, the power source is a different type of DC power source, such as an AC-DC power adapter.

[0084] The electrons flow from the negative terminal of the power source to the cathode 105. Then, the electrons flow through the aqueous solution 102 to the anode 107, and from the anode 107 to the positive terminal of the power source.

[0085] During electrolysis, water undergoes:

[0086] 1. Reduction reaction at the cathode, where H+ ions are reduced (receive electrons) and form liberated hydrogen gas (H 2 ),and

[0087] 2. Oxidation reaction at the anode, where OH- ions transfer additional electrons to the anode, generating and releasing oxygen (O 2 ).

[0088] In some embodiments, the system 1 of this example includes a polymer electrolyte membrane (PEM) 109 positioned between the cathode 105 and the anode 107 to separate H+ ions and OH- ions in the aqueous solution 102, thereby creating partitioned regions 110, 111 in the reaction vessel 101. The aqueous solution 102 in the partitioned region 110 near the cathode 105 has a higher concentration of H+ ions than OH- ions.

[0089] PEM 109 is a proton exchange membrane, preferably made of a perfluorosulfonic acid-based material or a similar proton conducting polymer. Examples of PEMs are available from Chemours Company FC, LLC of Wilmington, Delaware, USA as Nafion TM Commercially available. PEM 109 conducts protons (H+ ions) and inhibits the passage of electrons. In order to utilize this property of the polymer, PEM 109 is placed so that it separates cathode 105 and anode 107 and promotes the decomposition of water into hydrogen and oxygen.

[0090] An advantage of incorporating a PEM is that the PEM enables the system 1 to operate at relatively low temperatures while accelerating the production of hydrogen through ion separation within the aqueous solution 102 for faster reduction at the cathode 105. Separating the H+ ions and O- ions also prevents the ions from recombinating within the aqueous solution 102, which further increases the efficiency of the system 1 for generating hydrogen.

[0091] Polymer electrolyte membrane water electrolysis (PEMWE) uses sulfonated polymer membrane as electrolyte. Generally, PEM water electrolysis is carried out at relatively low temperature (30℃-80℃) and relatively high current density (1A / cm 2 -2A / cm 2 ) to produce gases of exceptional purity (99.999%), namely hydrogen and oxygen.

[0092] PEM electrolysis requires no corrosive electrolytes, takes up minimal space, and is safer than conventional alkaline electrolysis.

[0093] In a PEMWE, the generated oxygen is removed from the surface of the anode 107, while the remaining protons (H+) travel through the proton conducting membrane toward the cathode 105. At the same time, the electrons travel through the external circuit to the cathode 105. At the cathode 105, the protons and electrons recombine, resulting in the generation of hydrogen gas.

[0094] To further increase the rate of hydrogen production, in some examples, the system 1 may include a polymer electrolyte membrane (PEM) and multiple ultrasonic transducers placed at optimal locations within the aqueous solution 102. For example, the ultrasonic transducers may be placed close to the anode 107 and / or cathode 105, but leaving enough space for the aqueous solution 102 to easily flow around the anode 107 and / or cathode 105. Alternatively or additionally, the ultrasonic transducers may be positioned near the edge of the reaction vessel 101 to agitate the aqueous solution 102 and move ions toward the anode 107 and / or cathode 105.

[0095] However, PEM 109 is optional and not required, and is omitted in other examples of the present disclosure. Figure 4 The system 1 is shown without the optional PEM 109 .

[0096] Now return to Figure 3 In the above example, the electrodes 105 and 107 are rod-shaped electrodes with a circular cross section. The electrodes 105 and 107 are inserted into the aqueous solution 102 through the top wall 112 of the reaction vessel 101 .

[0097] In some examples, electrodes 105 , 107 are each flat rectangular electrodes positioned parallel to and spaced apart from each other within reaction vessel 101 .

[0098] In some examples, the electrodes (anode / cathode) may have different electrode geometries depending on the intended use. For example, the electrodes may be flat elongated plates. Such a geometry will disrupt any stable laminar flow within the electrolyte, generate turbulent vortices, and increase the interaction between water molecules and the electrodes.

[0099] Other electrode geometries for some example electrodes (anode / cathode) of the present disclosure include, but are not limited to, M-shaped electrodes (increased surface area) (similar to heat sinks), mesh electrodes (increased surface area), or porous electrodes (gas diffusion, improved mass transfer).

[0100] In other examples, electrodes 105, 107 are each a mesh electrode or a mesh electrode composed of a mesh or screen structure made of a conductive material. These mesh electrodes or mesh electrodes can be placed vertically on the inner surface of the reaction vessel 101. It should be understood that various configurations and shapes of electrodes suitable for the intended purpose of electrolysis are contemplated and are within the scope of the present invention. Some examples include, but are not limited to, electrodes in the shape of a plane and a coil.

[0101] The electrodes 105, 107 may be affected by the chemicals in the aqueous solution 102. The choice of electrode material depends on various factors, such as the chemical reaction being performed, the characteristics of the aqueous solution, and the desired durability and efficiency of the electrodes.

[0102] In some examples, cathode 105 and anode 107 are made of graphite, platinum or preferably stainless steel. In some examples, cathode 105 and anode 107 are solid electrodes, but in other examples, cathode 105 and anode 107 each include holes (tubular) or are porous. The structure of cathode 105 and anode 107 is selected according to the desired use and operating parameters of system 1. Platinum electrodes generally have strong corrosion resistance and durability, and are therefore resistant to degradation during water electrolysis. However, platinum electrodes degrade over long periods of time and / or under harsh conditions, such as when subjected to high current density. In order to minimize or prevent cathode 105 and anode 107 from deteriorating during electrolysis, cathode 105 and anode 107 may be coated with materials that promote better performance and life.

[0103] In some examples, cathode 105 and anode 107 are coated with graphene to minimize or prevent degradation of cathode 105 and anode 107. The coating not only prevents cathode 105 and anode 107 from degradation, but also enhances the electrical performance of cathode 105 and anode 107.

[0104] Graphene is a 2-D material, a single layer of carbon atoms arranged in a hexagonal lattice structure, which makes it corrosion resistant due to its chemical stability. In addition, the high electrical conductivity of graphene improves the overall efficiency of the cathode 105 and the anode 107 during the electrolysis process. The electrical conductivity is improved due to the availability of free electrons in the graphene lattice, which has a hexagonal structure. The presence of Dirac cones in the graphene electronic band structure indicates the quality of its electrical properties.

[0105] The electronic structure of graphene consists of two conical energy bands that meet at two different points (Dirac cone / Dirac point), which represent the energy dispersion relation of electrons. The energy dispersion relation is the product of the simplified Planck constant, the Fermi velocity, and the momentum of the electron. The linear relationship between energy and momentum allows electrons to move with high mobility, showing the excellent conductivity of the material, leading to the handling of higher current densities without degrading the electrode.

[0106] Coating the cathode 105 and anode 107 with graphene increases the life of the cathode 105 and anode 107 because graphene has strong corrosion resistance in harsh chemical and electrical environments. The graphene coating also increases the conductivity properties of the cathode 105 and anode 107 for more efficient operation of the system when performing electrolysis of water to generate hydrogen.

[0107] Another example of a coating material is goldenene, a 2-D material, i.e., a monolayer of gold atoms. Goldenene provides similar benefits to graphene. In addition, gold nanoparticle-based plasmonic photocatalysts driven by localized surface plasmon resonance excitation of gold nanoparticles (Au NPs) can be efficient solar-to-chemical converters due to their broad spectral response and can be used for plasma water splitting and the generation of oxygen from water and oxygen (O 2 )Synthesis of H 2 O 2 .

[0108] The hydrogen collector 113 extends through the top wall 112 of the reaction vessel 101 and is positioned above the cathode 105 to collect hydrogen generated during electrolysis. The oxygen collector 114 extends through the top wall 112 of the reaction vessel 101 and is positioned above the anode 107 to collect oxygen generated during electrolysis. In this example, the hydrogen collector 113 and the oxygen collector 114 are the same or substantially the same as each other, and for simplicity, the elements of the hydrogen collector 113 will be described below. In other examples, the hydrogen collector 113 and the oxygen collector 114 may be different sizes and / or shapes from each other, suitable for the intended purpose of collecting the corresponding gases.

[0109] The hydrogen collector 113 is generally elongated, having a closed end 115 and an open end 116. The hydrogen collector 113 preferably includes an inner chamber 117.

[0110] The cathode 105 is partially inserted through the open end 116 of the hydrogen collector 113 so that hydrogen gas emitted from around the cathode 105 during electrolysis rises within the hydrogen collector 113 into the inner chamber 117. The hydrogen gas is thus collected by the hydrogen collector 113.

[0111] In contrast, the oxygen collector 114 collects oxygen exhausted from around the anode 107 .

[0112] The hydrogen collector 113 includes a hydrogen outlet 118 that allows hydrogen to flow out of the hydrogen collector 113 for use or storage. In some examples, the hydrogen outlet 118 delivers the hydrogen to a storage tank so that the hydrogen can be stored for later use. In other examples, the hydrogen outlet 118 delivers the hydrogen to a fuel cell or alternatively a burner so that the generated hydrogen can be utilized in real time or near real time to minimize or avoid the need to store large amounts of generated hydrogen.

[0113] The oxygen collector 114 includes an oxygen outlet 119 that allows oxygen to flow out of the oxygen collector 114 for use or storage. In some examples, the oxygen outlet 119 transfers the oxygen to a storage tank so that the oxygen can be stored for later use. In other examples, the oxygen outlet 119 transfers the oxygen to another system so that the generated oxygen can be utilized in real time or near real time to minimize or avoid the need to store large amounts of generated oxygen.

[0114] The hydrogen collector 113 preferably includes a pressure sensor 120 disposed in the flow path of the hydrogen collector 113 to sense the pressure of the hydrogen flowing out through the hydrogen outlet 118. The hydrogen pressure sensor 120 generates a hydrogen pressure signal and transmits the hydrogen pressure signal to the main controller 2. The main controller 2 uses the hydrogen pressure signal to calculate the volume and rate of hydrogen produced by the system 1. The hydrogen pressure signal thus forms part of a feedback loop in the system 1, which enables the main controller 2 to monitor the output of hydrogen and determine the operating efficiency of the system 1.

[0115] In this example, the configuration of the oxygen gas collector 114 is the same as that of the hydrogen gas collector 113 , but the oxygen gas collector 114 instead collects oxygen gas exhausted from around the anode 107 during electrolysis.

[0116] In this example, an oxygen pressure sensor 121 is provided in the flow path from the oxygen collector 114 to sense the pressure of the oxygen flowing out through the oxygen outlet 119. The oxygen pressure sensor 121 generates an oxygen pressure signal and transmits the oxygen pressure signal to the main controller 2. The main controller 2 uses the oxygen pressure signal to calculate the volume and rate of oxygen produced by the system 1. The oxygen pressure signal thus forms part of a feedback loop in the system 1 that enables the main controller 2 to monitor the output of oxygen and determine the operating efficiency of the system 1.

[0117] Although the gas pressure sensors 120 , 121 provide useful feedback to the primary controller 2 , in other examples of the present disclosure, one or both of the hydrogen pressure sensor 120 and / or the oxygen pressure sensor 121 may be omitted.

[0118] The system 1 includes a cathode 105 positioned at a predetermined distance S t-eThe ultrasonic transducer 215 is oriented such that the ultrasonic transducer 215 transmits ultrasonic waves at least partially toward the outer surface of the cathode to agitate the aqueous solution near the outer surface 106 of the cathode 105, thereby scavenging any bubbles of hydrogen gas formed at the outer surface 106 of the cathode 105 to expose the outer surface 106 of the cathode 105 to additional H+ ions for generating hydrogen gas. In some examples, the ultrasonic transducer 215 transmits ultrasonic waves that induce cavitation in the aqueous solution 102 near the outer surface 106 of the cathode 105.

[0119] In this example, the system 1 includes a plurality of additional ultrasonic transducers 216, 217, each of which is positioned at a predetermined distance S from the cathode 105. t-e In this example, there are two additional ultrasonic transducers 216, 217. The plurality of additional ultrasonic transducers 216, 217 are oriented so that the plurality of additional ultrasonic transducers 216, 217 transmit ultrasonic waves at least partially toward the outer surface of the cathode to agitate the aqueous solution near the outer surface 106 of the cathode 105, thereby clearing any bubbles of hydrogen gas formed at the outer surface 106 of the cathode 105 to expose the outer surface 106 of the cathode 105 to additional H+ ions for generating hydrogen gas. In some examples, the ultrasonic transducers 216, 217 transmit ultrasonic waves that induce cavitation in the aqueous solution 102 near the outer surface 106 of the cathode 105.

[0120] In other examples, the plurality of additional ultrasonic transducers 216, 217 are omitted. In other examples, the system 1 includes Figure 3 The two further ultrasonic transducers 216 , 217 shown are further ultrasonic transducers.

[0121] In other examples, the ultrasonic transducers 215-217 on the cathode side of the reaction vessel 101 are omitted entirely, e.g. Figure 5 shown.

[0122] In this example, the system 1 includes at least one or more anode-side ultrasonic transducers 218-220, each of which is positioned at a predetermined distance S from the anode 107. t-eIn this example, there are three anode-side ultrasonic transducers 218-220. The anode-side ultrasonic transducers 218-220 are oriented so that the anode-side ultrasonic transducers 218-220 transmit ultrasonic waves at least partially toward the outer surface 108 of the anode 107 to induce cavitation in the aqueous solution 102 near the outer surface 108 of the anode 107. Cavitation weakens the hydrogen bonds between water molecules of the aqueous solution 102, thereby separating individual water molecules that can be used to interact with the anode 107 to undergo an oxidation reaction at the anode 107, thereby oxidizing OH- ions and forming oxygen at the anode 107.

[0123] In some examples, system 1 includes Figure 3 The three anode side ultrasonic transducers 218-220 shown may be a greater or lesser number of anode side ultrasonic transducers. In other examples, the anode side ultrasonic transducers 218-220 are omitted entirely, such as Figure 6 shown.

[0124] For simplicity, the following description will refer to one ultrasonic transducer 215 and how the ultrasonic transducer 215 is driven by the transducer driver 202. However, the description is equally applicable to any other ultrasonic transducer that operates in the same manner as the ultrasonic transducer 215 to induce cavitation in the aqueous solution 102.

[0125] During electrolysis, ultrasound is introduced into the aqueous solution 102 to agitate the solution, increasing the collision rate between H+ and the cathode 105. Ultrasonic waves are transmitted through the aqueous solution 102, generating agitation and cavitation bubbles. The efficiency of the electrolysis process of producing hydrogen using water can be improved by adding ultrasound.

[0126] In examples of the present disclosure, at least one ultrasonic transducer is preferably driven at a frequency in the range of 20 kHz to 40 kHz to induce convection and agitation within the aqueous solution 102. In other examples of the present disclosure, the ultrasonic transducer is driven at different frequencies depending on the desired results.

[0127] Advantages of ultrasound transmission through aqueous solution 102 include:

[0128] 1. As the ultrasonic waves generate a stirring effect, the mass flow to the anode 105 and / or cathode 107 increases, thereby increasing the reaction rate. This also ensures that all components of the aqueous solution 102 are uniformly mixed in the reaction vessel 101.

[0129] 2. The agitation effect also regulates the temperature of the entire aqueous solution 102, which is beneficial to lowering the operating temperature.

[0130] 3. Remove / release bubbles that may adhere to the anode and / or cathode. Bubbles that remain on the anode and / or cathode reduce the exposed surface area of ​​the anode / cathode, thereby reducing the reaction rate.

[0131] 4. The formation and collapse of cavitation bubbles produces localized shock waves with energies ranging from 500 joules to thousands of joules. This further increases the reaction rate by weakening / destroying the hydrogen bonds between adjacent water molecules.

[0132] The proximity of the ultrasonic wave to the outer surface of the cathode / anode induces localized cavitation bubbles, which release energy in the form of microjets in the aqueous solution 102 when they implode. In addition to agitating the aqueous solution 102, the microjets from the cavitation weaken or break the hydrogen bonds of the water molecules in the aqueous solution 102. This helps the water molecules to quickly decompose into H+ ions and OH- ions, which contact the cathode / anode and are reduced and oxidized to generate hydrogen and oxygen at the cathode 105 and the anode 107, respectively.

[0133] The increased contact of the H+ ions with the cathode 105 speeds up the rate of the electrolysis process, producing a greater amount of hydrogen per unit time (consuming less energy for the same amount of hydrogen production compared to conventional methods). In addition, the optimal placement of the container geometry and cathode 105 to maximize contact with the H+ ions in the aqueous solution 102 also increases the output of the hydrogen produced.

[0134] In other examples of the present disclosure, the system 1 drives at least one ultrasonic transducer in the aqueous solution 102 at a higher frequency, such as 3 MHz to 20 MHz, preferably 10 MHz. The at least one ultrasonic transducer is preferably positioned near the top surface of the aqueous solution 120 to promote ultrasonic decomposition of water molecules in the aqueous solution 102. At a higher frequency in the range of 3 MHz to 20 MHz or higher, the ultrasonic waves emitted from each ultrasonic transducer perform ultrasonic decomposition and split the water molecules in the aqueous solution to generate hydrogen directly from the water. In these examples, the ultrasonic decomposition performed by each ultrasonic transducer can be performed instead of electrolysis or in addition to electrolysis to maximize the production of hydrogen.

[0135] In some examples, the ultrasonic transducer is positioned concentrically or approximately concentrically with the open end 116 of the hydrogen collector 113. The ultrasonic transducer is positioned to emit ultrasonic waves in a direction toward the cathode 105. In this example, the direction of the ultrasonic waves emitted by the ultrasonic transducer 215 is aligned with the longitudinal length of the cathode 105.

[0136] In some examples, the ultrasonic transducer 215 is an ultrasonic horn (ultrasonic horn). In these examples, the ultrasonic horn is capable of delivering high frequency and high intensity ultrasonic waves used in industrial systems for generating hydrogen.

[0137] In some examples, the ultrasonic horn is a Barbell Horn TM .Barbell Horn TMIt is capable of amplifying the ultrasonic amplitude while maintaining a large output diameter and radiation area. The BarbellHorn is disclosed in U.S. Patent No. 11,325,094. TM Examples of which are incorporated herein by reference.

[0138] In some examples, the ultrasonic horn is a rod horn, which includes a solid metal rod with a circular transverse cross-section and a longitudinal cross-section of variable shape. In other examples, the ultrasonic horn is a block horn, which includes a rectangular transverse cross-section and a longitudinal cross-section of variable shape.

[0139] The main controller 2 is electrically coupled to a power controller (not shown) that controls the power (electrode potential difference) applied to the cathode 105 and the anode 107 during electrolysis. The main controller 2 activates the power controller to deliver power to the cathode 105 and the anode 107 to start the electrolysis reaction, and controls the power level to change the rate of the electrolysis reaction.

[0140] The main controller 2 also deactivates the power controller to stop the electrolysis reaction.

[0141] The main controller 2 is also electrically coupled to the transducer driver 202 to start and control the operation of the transducer driver 202. The transducer driver 202 is electrically coupled to the ultrasonic transducer 215 to drive the ultrasonic transducer 215 to generate ultrasonic waves. In an example where the system includes multiple ultrasonic transducers, the system 1 includes multiple transducer drivers 202, each of which is electrically coupled to control a corresponding one of the ultrasonic transducers. In another example, the system includes a transducer driver that includes multiple outputs that are electrically coupled to multiple ultrasonic transducers to drive the ultrasonic transducers to generate ultrasonic waves, respectively. For simplicity, the following description only relates to one transducer driver 202 that is coupled to only one ultrasonic transducer 215.

[0142] The master controller 2 coordinates the power levels delivered to the cathode 106 and anode 107 with the operation of the transducer driver 202 to optimize the operation of the system 1 for generating hydrogen gas.

[0143] The placement of ultrasonic transducer 215 (and similarly other ultrasonic transducers 216-220) is an important factor in controlling the electrolysis reaction rate. Transducers placed in close proximity to the cathode / anode increase the efficiency of mechanical stirring around the cathode / anode, thereby increasing the reaction rate.

[0144] In addition, the placement of the transducers also determines the area where cavitation bubbles form and collapse. The implosion of cavitation bubbles creates a localized shock wave that is close to the cathode / anode, promoting efficient and accelerated release of the bubbles from the cathode / anode surface. Continuous stirring and convection also ensure that there is no stagnation in the aqueous solution and that every molecule / ion flows toward the cathode / anode.

[0145] Each ultrasonic transducer is positioned according to where the ultrasonic transducer creates an active cavitation bubble formation and collapse zone. The goal is to ensure that the cavitation bubble formation zone is in close proximity to the cathode / anode surface.

[0146] Cavitation bubbles are usually formed in the rarefaction region of ultrasonic waves (longitudinal mechanical waves). In the rarefaction region, the particles / layers of the medium (electrolyte) are stretched apart, creating voids (cavitation bubbles). With each passing wave, the cavitation bubbles in the rarefaction region grow to a size that is no longer sustainable due to the pressure difference between the inside and outside of the bubble.

[0147] The huge pressure difference then causes the bubble to implode instantly, creating localized conditions of up to 200 atmospheres and 5000K (because these conditions are on an infinitesimally small scale, the dissipation rate is 10 -4 Ks -1 ). The violent implosion of the cavitation bubbles also releases shock waves that travel through the medium (water), inducing microjets. These microjets shake the bubbles off the electrodes to continuously maximize the exposed surface area, thereby increasing the reaction rate.

[0148] As the electrode moves away from the transducer, the intensity of the ultrasound (in Wcm -2 Thus, in some examples, the space between the transducer and the electrode is kept close to 1x (one) wavelength of the ultrasound. In other examples, the space between the transducer and the electrode is kept close to a multiple (multiple) of one wavelength of the ultrasound.

[0149] To find the wavelength of ultrasound, use the following formula:

[0150]

[0151] where 'λ' is the wavelength,

[0152] 'v' is the speed of the wave, and

[0153] 'f' is the wave frequency.

[0154] To find the speed of ultrasound in water (electrolyte), the following formula is used:

[0155]

[0156] where “k” is the bulk modulus of the aqueous solution (for water, 2.2×10 9 Pa), and

[0157] 'ρ' is the density of the aqueous solution (for water, this is 1000 kgm -3 )

[0158] Since the preferred range of ultrasound transmission in the system 1 is set to 20 kHz - 40 kHz, the wavelength range can be found by calculating the minimum wavelength value and the maximum wavelength value.

[0159] and

[0160]

[0161] Therefore, for a frequency range of 20kHz to 40kHz, the single wavelength placement distance between the anode / cathode and the transducer is 37mm to 74mm.

[0162] In other examples, each transducer is spaced farther from the anode / cathode than one wavelength. In some examples, such as for but not limited to industrial settings, each transducer is spaced from the anode / cathode by a distance equal to or substantially equal to a multiple of the wavelengths of the ultrasonic waves emitted by the ultrasonic transducer.

[0163] The wavelength is related to the frequency of the ultrasound. Depending on the intensity (input power) of the ultrasound, each ultrasonic transducer can be spaced 1x or 2x the wavelength of the ultrasound from the anode / cathode. If the ultrasonic transducer is operated at a higher power, the intensity of the ultrasound is higher, and the ultrasonic transducer can be positioned 2x, 3x, or more wavelengths away from the anode / cathode.

[0164] The introduction of multiple transducers in close proximity to the cathode / anode, especially at the cathode, results in more agitation and a large number of cavitation bubbles collapsing along the length of the cathode / anode.

[0165] like Figures 3 to 6 As shown, a plurality of ultrasonic transducers 215-220 are placed at set locations within the aqueous solution 102. In these examples, the ultrasonic transducers 215-220 are mounted to the side wall 103 of the reaction vessel 101. However, in other examples, the ultrasonic transducers 215-220 are spaced apart from the side wall 103 of the reaction vessel 101.

[0166] In some examples, when all ultrasonic transducers 215-217 are aligned in the same direction and facing cathode 105, collective agitation increases, causing H+ ions to interact with the surface of cathode 105, increasing the reaction rate (hydrogen production). The placement of multiple ultrasonic transducers 218-220 also increases the number of cavitation bubble collapse areas adjacent to anode 107, further weakening the hydrogen bonds between water molecules, separating them, and promoting the interaction of individual water molecules with anode 107, again increasing the reaction rate.

[0167] Now refer to the accompanying drawings Figure 7 In other examples, the system 1 includes a plurality of ultrasonic transducers 221-223 positioned at least partially around the cathode 105. In these examples, the ultrasonic transducers 221-223 emit ultrasonic waves that bombard the cathode 105 from multiple angles. Figure 7 In the example shown, there are three ultrasonic transducers 221-223 distributed around the cathode 105 at an angle of 120° or close to 120°. In other examples, around the cathode 105, Figure 7 Compared to the shown, there are more or less ultrasonic transducers positioned at the same or different pitches and angles. For example, in the case of four ultrasonic transducers, the ultrasonic transducers can be equally spaced around the cathode 105 at an angle of 90° or close to 90°.

[0168] Now refer to the accompanying drawings Figure 8 In some examples, the ultrasonic transducers 221-223 are offset relative to each other along the length of the cathode 105 and are positioned at least partially around the cathode 105. In these examples, the ultrasonic transducers 221-223 are positioned on or approximately on a spiral path 224 ( Figure 8 The purpose of this ultrasonic transducer arrangement is to bombard the cathode 105 with ultrasonic waves from multiple or all directions to increase the reduction reaction at the cathode 105.

[0169] In some examples, the ultrasonic transducer is used as described above and as Figure 7 and Figure 8 The same or similar configuration of ultrasonic transducers 221-223 shown positioned around cathode 105 is positioned around anode 107. In the case of anode 107, the purpose of this ultrasonic transducer arrangement is to bombard anode 107 with single water molecules from multiple or all directions to increase the oxidation reaction at anode 107. In some examples, ultrasonic transducers are positioned around anode 107 but not around cathode 105, or vice versa.

[0170] Introducing an ultrasonic transducer into a system containing PEM 109 increases the overall yield of hydrogen produced. This also reduces the need for expensive precious metal electrode coatings used as catalysts while increasing the reaction rate.

[0171] The distance between the anode 107 and the ultrasonic transducers 218-220 is 1 x λ (wavelength) of the ultrasonic waves generated by each ultrasonic transducer 218-220. The low pressure (rarefied) region causes cavitation bubbles to be formed in close proximity to the anode 107, and upon rupture, releases high energy shock waves in the local area, destroying the hydrogen bonds between the water molecules and promoting an increased number of free water molecules to impact the anode 107 and then split into oxygen atoms (bonded together to form oxygen molecules / gas) and hydrogen (H+) ions. The hydrogen ions travel through the PEM 109 and receive electrons that travel through the power supply at the cathode 105. This causes the hydrogen atoms to be collected around the cathode 105 by the hydrogen collector 113. The hydrogen atoms covalently bond to form hydrogen gas (H 2 ). Due to the increased efficiency caused by the use of ultrasound, the process continues just as it would without the ultrasonic transducer, albeit at a higher reaction rate, producing a greater amount of "green hydrogen" over the same duration.

[0172] Multiple ultrasonic transducers are controlled to operate under precise parameters based on their positioning around each other. This ensures that the ultrasonic transmission from each ultrasonic transducer has the best effect on the cathode / anode and is not degraded by waves from adjacent ultrasonic transducers. In some examples, a single driver IC with multi-channel transducer control outputs is used to control the transducers to drive single or multiple transducers simultaneously.

[0173] As described below, each transducer driver 202 drives a corresponding ultrasonic transducer 215 to maximize the power delivery of ultrasonic waves emitted from the ultrasonic transducer 215 regardless of the temperature and / or characteristics of the aqueous solution 102 .

[0174] The transducer driver 202 includes an H-bridge circuit connected to the ultrasonic transducer 215. The H-bridge circuit generates an AC driving signal to drive the ultrasonic transducer 215 to generate and transmit ultrasonic waves. A microchip is connected to the H-bridge circuit to control the H-bridge circuit to generate the AC driving signal.

[0175] The microchip will be described in detail below. In summary, the microchip includes an oscillator that generates a master clock signal, a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and low during a negative half cycle of the master clock signal. The oscillator generates a second phase clock signal that is high at a second time during a negative half cycle of the master clock signal and low during a positive half cycle of the master clock signal. The phases of the first phase clock signal and the second phase clock signal are center aligned.

[0176] The transducer driver 202 includes a pulse width modulation (PWM) signal generator subsystem, which will be described in detail below. The PWM signal generator subsystem includes a delay locked loop that uses a first phase clock signal and a second phase clock signal to generate a dual-frequency clock signal that is twice the frequency of the main clock signal.

[0177] The delay locked loop synchronizes the first phase clock signal and the second phase clock signal, and adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to the driver control signal to generate a first phase output signal and a second phase output signal. The first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate an AC drive signal to drive the ultrasonic transducer 215.

[0178] The first phase output signal terminal outputs the first phase output signal to the H-bridge circuit. The second phase output signal terminal outputs the second phase output signal to the H-bridge circuit. The feedback input terminal receives a feedback signal from the H-bridge circuit, and when the H-bridge circuit drives the ultrasonic transducer 215 with the AC drive signal, the feedback signal indicates an operating parameter of the H-bridge circuit or the AC drive signal.

[0179] The transducer driver 202 includes an analog-to-digital converter (ADC) subsystem including at least one ADC input terminal for receiving an analog signal. The ADC input terminal is connected to a feedback input terminal so that the ADC subsystem receives a feedback signal from the H-bridge circuit. The ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal.

[0180] The transducer driver 202 includes a digital processor subsystem that receives an ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate a driver control signal. The digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem. The transducer driver 202 also includes a digital-to-analog converter (DAC) subsystem that includes a digital-to-analog converter (DAC) that converts the digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit.

[0181] The DAC output terminal outputs an analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the ultrasonic transducer 215 in response to a feedback signal indicating the operation of the ultrasonic transducer to control cavitation in the aqueous solution. The intensity of the ultrasonic wave emitted by the ultrasonic transducer 215 is controlled by the level of the predetermined voltage.

[0182] The ultrasonic transducer 215 improves the efficiency of the electrolysis process because the energy generated by the ultrasonic waves emitted by the ultrasonic transducer 215 and the cavitation in the aqueous solution 102 weakens or destroys the hydrogen bonds in the water molecules. In some examples, the ultrasonic transducer 215 generates ultrasonic waves with a frequency of 20 kHz to 40 kHz, preferably 26 kHz, which stirs the aqueous solution 102 by causing a large number of local cavitation implosions (the formation and collapse of tiny bubbles in the solution). This cavitation generates local areas of high pressure and high temperature in the aqueous solution 102, thereby increasing the rate of the electrolysis reaction.

[0183] In other examples, the transducer driver 202 drives the ultrasound transducer 215 at a higher frequency of 2 MHz to 5 MHz or 3 MHz 200 kHz.

[0184] In other examples of the present disclosure, the transducer driver 202 drives the ultrasonic transducer 215 at a frequency in the range of 20 kHz to 5 MHz.

[0185] The ultrasound intensity required for ultrasonic electrolysis of water depends on various factors, such as the size and shape of the reaction vessel, the characteristics of the aqueous solution, and the desired effect of ultrasound on the electrolysis process. In some examples, system 100 uses high intensity ultrasound to electrolyze water where cavitation is desired.

[0186] In some examples of the present disclosure, the driver device 202 drives the ultrasonic transducer 215 to emit an intensity of 0.05 W cm -2 Up to 0.5Wcm -2 or preferably 0.1 Wcm -2 However, other intensity values ​​and ranges are contemplated, and those skilled in the art will appreciate that in other examples, the intensity value or range will be selected based on the use and application of the system. For example, it will be appreciated that in industrial applications, a higher ultrasound intensity, such as 0.5 W cm -2 Up to 5Wcm -2 To generate hydrogen.

[0187] The intensity of the ultrasonic waves emitted by the ultrasonic transducer 215 is controlled by an algorithm implemented in the transducer driver 202. The algorithm works in conjunction with the integrated circuit within the transducer driver 202, using a feedback loop to continuously adjust the intensity and frequency of the ultrasonic waves generated by the ultrasonic transducer 215 to ensure optimal hydrogen production.

[0188] The transducer driver 202 uses continuous monitoring of the volume of hydrogen produced to adjust the frequency and / or intensity of the ultrasonic waves emitted by the ultrasonic transducer 215. The gas pressure sensor 117 in the hydrogen collector 112 records the increase in gas pressure over time to determine the gas production rate. This information is relayed to the transducer driver 202 in the form of a gas pressure signal. The transducer driver 202 then adjusts the frequency and / or intensity of the ultrasonic waves emitted by the ultrasonic transducer 215 to increase the hydrogen production rate and maintain the rate. This forms a feedback loop between the initial parameters (frequency and intensity) and the adjusted parameters (frequency and intensity).

[0189] In the examples of the present disclosure using high frequency ultrasound (~3MHz±200kHz), high frequency ultrasound can lead to more efficient cavitation (the formation and collapse of small bubbles in aqueous solution). When the bubbles collapse, they produce localized areas of high temperature and pressure at the cavitation bubbles in a very short time, which increases the reaction rate and promotes the extraction of hydrogen. High frequency ultrasound leads to small and stable cavitation bubbles, which leads to more efficient energy transfer and more efficient mixing of aqueous solutions.

[0190] Direct ultrasonic electrolysis

[0191] Seawater can be used as an electrolyte in electrolysis applications. Seawater is a naturally occurring electrolyte solution containing various dissolved salts and ions such as sodium, chloride, magnesium, and calcium.

[0192] In conventional systems for producing hydrogen from seawater, seawater is first desalinated to remove dissolved salts, and then the resulting purified water is electrolyzed to produce hydrogen. However, with the use of ultrasound and the introduction of frequency and / or intensity modulation by transducer driver 202, system 100 is able to directly electrolyze seawater to produce hydrogen. The systems of some examples of the present disclosure eliminate the expensive and time-consuming desalination process.

[0193] When the system 100 is in operation, ultrasonic waves emitted by the ultrasonic transducer 215 are applied to the seawater, which causes cavitation (the formation and collapse of bubbles). This phenomenon creates localized areas of high pressure and temperature in the cavitation bubbles in the seawater in a very short period of time, resulting in increased mass and heat transfer rates. The energy generated by cavitation weakens or destroys the hydrogen bonds between water molecules.

[0194] Ultrasonic waves emitted by the ultrasonic transducer 215 displace solutes present in the seawater to promote electrolysis near the surface of the cathode 105 .

[0195] Improved mass transfer enhances mixing and movement of reactants near electrodes 105, 106, improving the distribution of ions in aqueous solution 102 (seawater). Ions move freely within aqueous solution 102 (seawater), just as they do in desalinated seawater in a conventional electrolysis process.

[0196] The system of the examples of the present disclosure enables precise control of the frequency and intensity of ultrasonic waves emitted from the ultrasonic transducer to precisely control the system and adapt to changes in reaction conditions in the reaction vessel. The ultrasonic waves reduce scale formation on the electrode and promote the formation of a more uniform and well-defined electrode surface, which improves the efficiency and durability of the electrode over time.

[0197] In some examples, the ultrasonic transducer is positioned to emit ultrasonic waves upward in a direction substantially aligned with the longitudinal length of the hydrogen collector 113 or the oxygen collector 114. The ultrasonic waves emitted by the ultrasonic transducer control the distribution of hydrogen bubbles in the aqueous solution 102. Having at least one ultrasonic transducer as an ultrasonic source at the base of the corresponding anode / cathode ensures effective agitation of the aqueous solution 102. The agitation effect exposes more ions to the surface of the anode / cathode, thereby increasing gas production.

[0198] Each of the above-described ultrasonic transducers is electrically coupled to one or more transducer drivers, such as transducer driver 202 .

[0199] The placement of each ultrasonic transducer relative to the respective anode 107 or cathode 105 depends on the specific application and the characteristics of the aqueous solution 102. Ideally, the transducers are placed in close proximity to the outer surface 106, 18 of the anode / cathode (below or to the side of the anode / cathode) to promote the formation of cavitation bubbles and improve the efficiency of the electrolysis process.

[0200] The placement of the ultrasonic transducer in the reaction vessel 101 also depends on the size and geometry of the reaction vessel 101 and the properties of the aqueous solution 102 .

[0201] The size of the reaction vessel 101 affects the electrolysis rate due to the following considerations:

[0202] Large capacity transportation :

[0203] The rate at which ions reach cathode 105 and anode 107 is affected by the distance the ions need to travel to contact cathode 105 and anode 107. In smaller reaction vessels, this distance is smaller, shortening the path for ions to reach the electrodes and resulting in faster gas generation.

[0204] Electrode surface area :

[0205] Large reaction vessels allow for large or multiple electrodes, increasing the total surface area available for ion contact and increasing the volume of gas produced (increasing productivity). In some examples of the present disclosure, system 100 includes a greater number of electrodes than cathode 105 and anode 107 of the above examples.

[0206] The geometry of the reaction vessel affects the electrolysis process rate due to the following reasons:

[0207] Electrode location :

[0208] The cathode / anode positions are selected based on the geometry of the reaction vessel. The spacing between the cathode 105 and the anode 107 is also selected based on the geometry of the reaction vessel 101. The distance between the cathode 105 and the anode 107 and their relative positioning affect the number of ions that contact them, thereby affecting the reaction rate.

[0209] Ion density around the electrode :

[0210] The shape of the reaction vessel affects the electrolyte distribution (ion density) around the cathode 105 and the anode 107. Uniform electrolyte distribution around the cathode 105 and the anode 107 promotes efficient ion transport and increases the reaction rate.

[0211] Optimization of reaction vessel size requires consideration of the balance between ion transport distance to the electrodes and available electrode surface area for ion contact.

[0212] Scalability :

[0213] In some examples, the shape of the reaction vessel is selected for industrial-scale use. This means that the shape of the reaction vessel is suitable for the desired hydrogen production capacity and is easy to maintain and operate.

[0214] The size and geometry of the reaction vessel are parameters that influence the performance, efficiency and rate of the electrolysis process. The introduction and placement of at least one ultrasonic transducer within the reaction vessel is determined by the size and geometry of the reaction vessel. This is also a factor that determines the type of ultrasonic transducer placed within the electrolyte.

[0215] Now refer to the accompanying drawings Fig. 9 , some examples of the ultrasonic transducer array 122 include three ultrasonic transducers 215-217 held by a transducer holder 123. Each of the ultrasonic transducers 215-217 has a diameter D T The center of each of the ultrasonic transducers 215-217 is spaced apart from the center of an adjacent one of the ultrasonic transducers 215-217 by a distance S T .

[0216] Figure Fig.10 An example system is shown with some relevant dimensions labeled. The relationship between these dimensions of the example system is summarized in Fig.11 1 and 2. The dimensions and relationships between the parameters of the components are specific to the described example. The present disclosure is not limited to the specific dimensions and relationships disclosed herein, and other dimensions and relationships are also contemplated. For example, those skilled in the art will appreciate that the dimensions and relationships may be modified to scale up the system, such as for industrial generation of hydrogen.

[0217] exist Fig.10 In the example shown, the reaction vessel 101 is a flat-bottomed cylindrical container with a vertical (Dv) height (hv) ratio of 1:1. In other examples of the present disclosure, reaction vessels of different shapes are envisioned. In some examples, the reaction vessel is a rectangular (cuboid) shape. In some examples, the reaction vessel is a variable depth container with a non-planar base to control the mass flow rate in the reaction vessel.

[0218] In this example, the anode and cathode each have a v ≤l e ≤120%*h v The length within the range (l e ), of which 70%–80% is the length (l e ) is immersed in an aqueous solution.

[0219] The immersion length of the anode / cathode is denoted as l i In this example, the diameter of each electrode (D e ) is 7%≤Dv≤20%.

[0220] In this example, the diameter D of each transducer is T It may be 2 cm–5 cm. However, other transducer diameters are also contemplated, and the transducer diameter selected will depend on the intended use and function of the system for generating hydrogen. For larger systems for generating hydrogen, the relative dimensions described herein may be scaled up.

[0221] In some examples, the ultrasonic transducer uses thickness mode vibration to generate ultrasonic waves, where the thickness of the ultrasonic transducer is a determining factor in its resonant frequency. However, other types of ultrasonic transducers are also contemplated.

[0222] In this example, the spacing between the ultrasonic transducers is S T , and is set to 1 / 2*D T .

[0223] In this example, the volume of aqueous solution can be increased from 75% to 85% of the maximum fill height (he ) is determined. However, other aqueous solution volumes are also contemplated, and the skilled person will understand how to calculate the aqueous solution fill volume based on the parameters of the reaction vessel configured for the intended purpose.

[0224] In this example, the anode or cathode E s The placement is from the center of the anode / cathode to the center of the cylindrical reaction vessel (D v +1 / 2*D e 25%-30% of the total).

[0225] In some examples, different shapes of disk-shaped transducers and ultrasonic horns (ultrasonic horns) are selected to transmit ultrasound throughout the electrolytic solution 102 within the reaction vessel 101 .

[0226] Now refer to the accompanying drawings Fig.12 , some example systems 124 include a membrane electrode assembly (MEA) 125 for water electrolysis. The MEA 125 includes a polymer electrolyte membrane (PEM) 126 positioned or sandwiched between an anode 127 and a cathode 128.

[0227] PEM 126 is a proton exchange membrane, preferably made of a perfluorosulfonic acid-based material or a similar proton conducting polymer. Examples of PEMs are available from Chemours Company FC, LLC of Wilmington, Delaware, USA as Nafion TM Commercially available. PEM 126 conducts protons (H+ ions) and inhibits the passage of electrons. To utilize this property of the polymer, PEM 126 is placed so that it separates cathode 128 and anode 127 and promotes the decomposition of water into hydrogen and oxygen.

[0228] PEM electrolysis requires no corrosive electrolytes, takes up minimal space, and is safer than conventional alkaline electrolysis.

[0229] In a PEMWE, the generated oxygen is removed from the surface of the anode 127, while the remaining protons (H+) travel through the proton conducting membrane toward the cathode 128. At the same time, the electrons travel through the external circuit to the cathode 128. At the cathode 128, the protons and electrons recombine, resulting in the generation of hydrogen gas.

[0230] In these examples, the anode 127 and cathode 128 are each planar or substantially planar electrodes. In these examples, the anode 127 and cathode 128 are each provided with a respective gas diffusion layer (GDL). In these examples, the anode 127 and cathode 128 are each gas diffusion electrodes (GDE), preferably made of a porous conductive material. The anode 127 and cathode 128 are each preferably coated with at least one catalyst to promote the electrochemical reaction.

[0231] In MEA 125, anode 127 and cathode 128 are preferably noble metal electrodes, and noble metal oxides are electrocatalysts (eg, but not limited to, platinum, iridium, iridium dioxide (IrO2), rhodium, rhodium oxide (RhO2)).

[0232] In some examples, the anode 127 and cathode 128 are each porous and contain interconnected pores or channels throughout their structure. This porosity acts as an increased surface area for the catalyst to interact with water molecules, increasing the efficiency of the electrochemical reaction, and the diffusion of protons (H+) to the cathode side.

[0233] Now refer to the accompanying drawings Figures 13 to 16 In some examples, MEA 125 is positioned within housing 129, which is preferably a sealed container configured to allow reactants and products to flow. Seals and gaskets ensure a tight and secure closure, resisting gas and / or liquid pressure within housing 129 and preventing leakage.

[0234] In some examples, housing 129 includes a first housing portion 130 and a second housing portion 131 coupled to each other along a sealing interface 132 .

[0235] In some examples, first housing portion 130 includes a sidewall 133 coupled to an end wall 134. A first interior chamber 135 is formed between at least a portion of sidewall 133 and end wall 134. Anode 127 of MEA 125 is positioned on an opposite side of first housing portion 130 from end wall 134. An airtight or substantially airtight seal is preferably provided between anode 127 and sidewall 133.

[0236] An inlet port 136 is provided on the first housing portion 130. In this example, the inlet port 136 is located on the end wall 134. The inlet port 136 provides a water flow path to enable water to flow from a water source into the first interior chamber 135.

[0237] An outlet port 137 is provided on the first housing portion 130. In this example, the outlet port 137 is positioned on the end wall 134 and is spaced apart from the inlet port 136 at a corner of the end wall 134 opposite the inlet port 136. The outlet port 137 provides an oxygen and water flow path to enable the oxygen and water to flow out of the first interior chamber 135 for storage or use.

[0238] In some examples, first housing portion 130 includes an anode connector 138 to enable anode 127 to be connected to a power source, such as Fig.12 A DC power supply 139 is shown.

[0239] Now refer to the accompanying drawings Fig.15 and Fig.16In some examples, the system 124 includes at least one ultrasonic transducer 140-146 positioned within the first interior chamber 135. In this example, the system 124 includes nine ultrasonic transducers 140-146, which are respectively held in three separate transducer holders 147-149 coupled to the first housing portion 130.

[0240] Each ultrasonic transducer 140 - 146 is driven by a corresponding transducer driver 202 , as described herein with respect to the ultrasonic transducer 215 .

[0241] In this example, the ultrasonic transducers 140-146 transmit ultrasonic waves at least partially toward the anode 127 to induce cavitation in the water 150 within the first interior chamber 135 near the surface of the anode 127. The cavitation weakens the hydrogen bonds between the water molecules, thereby separating individual water molecules that are available to interact with the anode 127 to undergo an oxidation reaction at the anode 127, thereby oxidizing the OH- ions and forming oxygen and H+ ions at the anode 107. The H+ ions pass through the PEM 126 to the cathode 128.

[0242] Again, refer to the attached drawings Figures 13 to 15 In some examples, second housing portion 131 includes sidewall 151 coupled to end wall 152. Second interior chamber 153 is formed between at least a portion of sidewall 151 and end wall 152. Cathode 128 of MEA 125 is positioned on an opposite side of second housing portion 131 from end wall 152. An airtight or substantially airtight seal is preferably provided between cathode 128 and sidewall 151.

[0243] At least one hydrogen outlet port 154, 155 is provided on the second housing portion 131. In this example, two hydrogen outlet ports 154, 155 are provided on the second housing portion 131. In this example, the hydrogen outlet ports 154, 155 are positioned on the end wall 152. Each hydrogen outlet port 154, 155 provides a flow path to enable hydrogen gas to flow out of the second interior chamber 153 for storage or use.

[0244] In some examples, the second housing portion 131 includes a cathode connector 156 to enable the cathode 128 to be connected to a power source, such as Fig.12 A DC power supply 139 is shown.

[0245] In some examples, cathode 128 is a cathode ultrasonic transducer driven to vibrate by transducer driver 202 or an oscillator. In these examples, the vibrations in cathode 128 help to clean out any hydrogen gas formed on the surface of cathode 128 to expose the surface of cathode 128 to additional H+ ions for generating hydrogen gas.

[0246] Now refer to the accompanying drawings Fig.17, some examples of the system 157 of the present disclosure include a plurality of hydrogen generating cells 158 .

[0247] Each hydrogen generating cell 158 is a PEM system that is the same or similar to the above-described system 128. The hydrogen generating cells 158 are preferably coupled to one another in an array to produce hydrogen gas from water that is pumped through the hydrogen generating cells 158.

[0248] The operation of the hydrogen generating cells 158 is controlled by the main controller 2, which coordinates the operation of each hydrogen generating unit 158 ​​so that the array generates hydrogen at a desired rate. In some examples, the main controller 2 activates all hydrogen generating cells 158 or a subset thereof to generate hydrogen based on the desired hydrogen production rate. If the main controller 2 detects that the hydrogen production rate of the array is above a threshold, the main controller 2 deactivates one or more hydrogen generating cells in the hydrogen generating cells 158. Conversely, if the main controller 2 detects that the hydrogen production rate of the array is below a threshold, the main controller 2 activates one or more hydrogen generating cells 158 in the hydrogen generating cells. In this way, the main controller 2 can control the rate of hydrogen production to a safe level for the intended storage volume or use.

[0249] The master controller 2 coordinates the activation and deactivation of each hydrogen generating cell 158 while simultaneously optimizing the operation of each activated hydrogen generating cell 158. Thus, the master controller 2 maximizes the flexibility and efficiency of the system 157 to effectively generate hydrogen at a desired rate.

[0250] Now refer to the accompanying drawings Fig.18 , the transducer driver 202 includes a microchip, which is referred to herein as a power management integrated circuit or PMIC 300. The PMIC 300 is a microchip for driving the ultrasound transducer 215.

[0251] The transducer driver 202 provides precise control to ensure that each ultrasonic transducer operates at an optimal frequency (resonance) to maximize the displacement (amplitude / intensity) of the ultrasonic wave at the lowest possible power input. This is achieved by using the feedback loop function of the transducer driver 202, whereby the transducer driver 202 senses the current flowing through the ultrasonic transducer 215 and adjusts the driving frequency of the ultrasonic transducer 215 to maximize the active power consumed by the ultrasonic transducer 215. Therefore, the feedback loop ensures that the transducer driver 202 drives the ultrasonic transducer 215 at or near its resonant (optimal) frequency. The feedback loop of the transducer driver 202 is described in detail below.

[0252] In some examples, multiple ultrasound transducers are controlled to operate under precise parameters based on their positioning relative to each other. This ensures that the ultrasound transmission effect of each transducer on the electrode is maximized and is not degraded by waves from adjacent transducers.

[0253] In some examples, the transducers are controlled using a single transducer driver 202 with a multi-channel transducer control output to drive single or multiple transducers simultaneously.

[0254] In this disclosure, the terms chip, microchip and integrated circuit are interchangeable. A microchip or integrated circuit is a single unit that includes multiple interconnected embedded components and subsystems. A microchip is, for example, at least partially composed of a semiconductor such as silicon and is manufactured using semiconductor manufacturing techniques.

[0255] The transducer driver 202 includes a second microchip, referred to herein as a bridge integrated circuit or bridge IC 301, which is electrically connected to the PMIC 300. The bridge IC 301 is a microchip for driving a piezoelectric transducer, such as the ultrasound transducer 215. The bridge IC 301 is a single unit including multiple interconnected embedded components and subsystems.

[0256] In this example, the PMIC 300 and the bridge IC 301 are mounted to the same PCB of the transducer driver 202 .

[0257] The ultrasonic transducer 215 is electrically connected to the bridge IC 301 so that the ultrasonic transducer 215 can be driven by an AC drive signal generated by the bridge IC 301 when the system 100 is in operation.

[0258] The transducer driver 202 includes a processor in the form of a microcontroller 303, which is electrically coupled for communication with the communication bus 302. The microcontroller 303 receives power from a low dropout regulator (LDO) 304 driven by a power supply (not shown). The LDO 304 provides a stable, regulated voltage to the microcontroller 303 so that the microcontroller 303 can operate consistently even when there are variations in the voltage of the power supply.

[0259] The transducer driver 202 includes a voltage regulator in the form of a DC-DC boost converter 305 powered by a power supply. The boost converter 305 boosts the voltage of the power supply to a programmable voltage VBOOST. The programmable voltage VBOOST is set by the boost converter 305 in response to a voltage control signal VCTL from the PMIC 300. As will be described in more detail below, the boost converter 305 outputs the voltage VBOOST to the bridge IC 301. In other examples, the voltage regulator is a buck converter or another type of voltage regulator that outputs a selectable voltage.

[0260] The voltage control signal VCTL is generated by a digital-to-analog converter (DAC), which in this example is implemented within the PMIC 300. The DAC Fig.18300 because the DAC is integrated within the PMIC 300. The DAC and the technical benefits of integrating the DAC within the PMIC 300 are described in detail below.

[0261] In this example, the PMIC 300 is connected to a power connector 306 so that the PMIC 300 can receive power from a power source.

[0262] The microcontroller 303 acts as a master device on the communication bus 302, with the PMIC 300 being the first slave device. The communication bus 302 enables the microcontroller 303 to control the following functions within the transducer driver 202:

[0263] 1. All functions of the PMIC are highly configurable by the microcontroller 303.

[0264] 2. The current flowing through the ultrasonic transducer 215 is sensed by a high bandwidth sensing and rectifier circuit at a high common mode voltage (high side of the bridge). The sensed current is converted to a voltage proportional to the rms current and provided as a buffered voltage at the current sense output pin 309 of the bridge IC 301. This voltage is fed to and sampled in the PMIC 300 and provided in the form of a digital representation via an I2C request. Sensing the current flowing through the ultrasonic transducer 215 forms part of the resonant frequency tracking functionality. As described herein, the ability of the device to enable this functionality within the bridge IC 301 provides significant technical benefits.

[0265] 3. DAC integrated in PMIC 300 ( Fig.18 ) enables the DC-DC boost converter voltage VBOOST to be programmed between 10V and 20V.

[0266] Now refer to the accompanying drawings Fig.19 In this example, PMIC 300 is a stand-alone chip or integrated circuit that includes integrated subsystems and a plurality of pins that provide electrical input and output to PMIC 300. References to integrated circuits or chips are interchangeable in this disclosure, and either term encompasses a semiconductor device that may be constructed, for example, of silicon.

[0267] The PMIC 300 includes an analog core 310 including analog components including a reference block (BG) 311 , an LDO 312 , a current sensor 313 , a temperature sensor 314 , and an oscillator 315 .

[0268] As described in more detail below, oscillator 315 is coupled to a delay locked loop (DLL) that outputs pulse width modulated (PWM) phases A and B. Oscillator circuit 315 and DLL generate a two-phase center-aligned PWM output that drives an H-bridge in bridge IC 301 .

[0269] The DLL includes a plurality of delay lines connected end-to-end, where the total delay of the delay lines is equal to the period of the master clock signal clk_m. In this example, the DLL is implemented in a digital processor subsystem (referred to herein as digital core 316) of the PMIC 300, which receives a clock signal from an oscillator 315 and a regulated supply voltage from an LDO 312. The DLL is implemented in a large number (e.g., on the order of millions) of delay gates connected end-to-end in the digital core 316.

[0270] The implementation of the oscillator 315 and the DLL in the same integrated circuit of the PMIC 300 to generate a two-phase center-aligned PWM signal is unique because no signal generator component currently on the integrated circuit market has such an implementation.

[0271] As described herein, PWM is part of the functionality that enables the transducer driver 202 to accurately track the resonant frequency of the ultrasonic transducer 215 to maintain efficient transfer of electrical energy to kinetic energy, thereby optimizing the generation of hydrogen gas.

[0272] The PMIC 300 includes an integrated power switch VSYS that configures the PMIC 300 to power the analog core 310 with power from a power supply.

[0273] The PMIC 300 includes an embedded analog-to-digital converter (ADC) subsystem 318. The implementation of the ADC 318 together with the oscillator 315 in the same integrated circuit is unique in itself, because no other integrated circuit in the integrated circuit market includes an oscillator and an ADC implemented as sub-blocks within the integrated circuit. In conventional devices, the ADC is usually provided as a discrete component separate from the oscillator, wherein the separate ADC and oscillator are mounted to the same PCB. A problem with this conventional arrangement is that the two separate components, the ADC and the oscillator, unnecessarily occupy space on the PCB. Another problem is that the conventional ADC and the oscillator are usually connected to each other via a serial data communication bus (such as an I2C bus), which has a limited communication speed of up to 400kHz. Compared to conventional devices, the PMIC 300 includes the ADC 318 and the oscillator 315 integrated in the same integrated circuit, which eliminates any lag in the communication between the ADC 318 and the oscillator 315, meaning that the ADC 318 and the oscillator 315 can communicate with each other at a high speed such as the speed of the oscillator 315 (e.g., 20kHz to 40MHz).

[0274] In the PMIC 300 of this example, the oscillator 315 is running at 26 MHz and generates the clock signal SYSCLOCK at 26 MHz. However, in other examples, the oscillator 315 generates the clock signal at a frequency of 20 kHz to 40 kHz, preferably 26 kHz. The integrated circuits described herein are all configured to operate at the high frequency of the oscillator 315.

[0275] ADC 318 includes a plurality of feedback input terminals or analog inputs 319 , which include a plurality of GPIO inputs ( IF_GPIO1 - 3 ).

[0276] At least one of the feedback input terminal or the analog input 319 receives a gas pressure signal from the pressure sensor 117 .

[0277] At least one of the other feedback input terminals or analog inputs 319 receives a feedback signal from an H-bridge circuit in the bridge IC 301, the feedback signal indicating a parameter of the operation of the H-bridge circuit when the H-bridge circuit is driving the ultrasonic transducer 215 with the AC drive signal or the AC drive signal. As described below, the GPIO input terminals are used to receive a current sense signal from the bridge IC 301, the current sense signal indicating the root mean square (rms) current reported by the bridge IC 301. In this example, one of the GPIO input terminals is a feedback input terminal that receives a feedback signal from the H-bridge in the bridge IC 301.

[0278] The ADC subsystem 318 samples the analog signals received at the plurality of ADC input terminals 319 at a sampling frequency proportional to the frequency of the master clock signal. The ADC subsystem 318 then generates ADC digital signals using the sampled analog signals.

[0279] In this example, the ADC 318 incorporated in the PMIC 300 samples not only the RMS current flowing through the H-bridge 334 and the ultrasonic transducer 215, but also the voltage available in the system (eg, VBOOST), the temperature of the PMIC 300, and the GPIO inputs (IF_GPIO1-3).

[0280] The digital core 316 receives the digital signal generated by the ADC from the ADC subsystem and processes the ADC digital signal to generate a driver control signal. The digital core 316 transmits the driver control signal to the PWM signal generator subsystem (DLL 332) to control the PWM signal generator subsystem.

[0281] The rectifier circuits that exist on the market today have very limited bandwidth. Since the oscillator 315 of the PMIC 300 can operate over a wide range of 20kHz to 5MHz, a high bandwidth rectifier circuit is implemented in the PMIC 300. As will be described below, the RMS current in the H-bridge of the sensing bridge IC 301 forms part of a feedback loop that enables the transducer driver 202 to drive the ultrasonic transducer 215 with high accuracy. The feedback loop changes the game rules in the industry of driving ultrasonic transducers because it can adapt to any process variations (variations in resonant frequency) in the production of piezoelectric transducers and can compensate for temperature effects on the resonant frequency. This is achieved in part by integrating the ADC 318, oscillator 315, and DLL in the same integrated circuit of the PMIC 300. This integration enables these subsystems to communicate with each other at high speed (e.g., at a clock frequency of 20kHz to 5MHz).

[0282] ADC 318 includes voltage monitoring inputs VMON and VRTH and a temperature monitoring input TEMP. The temperature monitoring input TEMP receives a temperature signal from a temperature sensor 314 embedded in PMIC 300. This enables PMIC 300 to accurately sense the actual temperature within PMIC 300, so that PMIC 300 can detect any faults within PMIC 300 and faults of other components on the printed circuit board that affect the temperature of PMIC 300. Then, if there is a fault, PMIC 300 can control bridge IC 301 to prevent excitation of ultrasonic transducer 215 in order to maintain the safety of the system.

[0283] The PMIC 300 includes an LED driver 320 that, in this example, receives digital drive signals from the digital core 316 and provides LED drive output signals to six LEDs 321 to 326 that are configured to be coupled to output pins of the PMIC 300. Thus, the LED driver 320 can drive and dim the LEDs 321 to 326 in up to six independent channels.

[0284] The PMIC 300 includes a first digital-to-analog converter (DAC) 327 that converts a digital signal within the PMIC 300 into an analog voltage control signal that is output from the PMIC 300 via an output pin VDAC0. The first DAC 327 converts a digital control signal generated by the digital core 316 into an analog voltage control signal that is output via an output pin VDAC0 to control a voltage regulator circuit, such as the boost converter 305. Thus, the voltage control signal controls the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit to drive the ultrasonic transducer 215 in response to a feedback signal indicative of the operation of the ultrasonic transducer 215.

[0285] In this example, the PMIC 300 includes a second DAC 328 that converts a digital signal within the PMIC 300 into an analog signal that is output from the PMIC 300 via a second analog output pin VDAC1 .

[0286] Embedding the DAC 327 or DACs 327, 328 in the same microchip as other subsystems of the PMIC 300 allows the DACs 327, 328 to communicate with the digital core 316 and other components within the PMIC 300 at high speed without or with minimal communication lag. The DACs 327, 328 provide analog outputs that control external feedback loops. For example, the first DAC 327 provides a control signal VCTL to the boost converter 305 to control the operation of the boost converter 305. In other examples, the DACs 327, 328 are configured to provide a drive signal to a DC-DC buck converter as an alternative or in addition to the boost converter 305. Integrating two independent DAC channels in the PMIC 300 enables the PMIC 300 to manipulate the feedback loop of any regulator used in the driver device 202, and allows the driver device 202 to adjust the ultrasonic power of the ultrasonic transducer 215 or set analog thresholds for the absolute maximum current and temperature settings of the ultrasonic transducer 215.

[0287] The PMIC 300 includes a serial communication interface, which in this example is an I2C interface in conjunction with an external I2C address set via a pin.

[0288] The PMIC 300 also includes various functional blocks that include a digital machine (FSM) to implement the functionality of the microchip. These blocks will be described in more detail below.

[0289] Now refer to the accompanying drawings Fig. 20, a pulse width modulation (PWM) signal generator subsystem 329 is embedded within the PMIC 300. The PWM generator system 329 includes an oscillator 315, a frequency divider 330, a multiplexer 331, and a delay locked loop (DLL) 332. As will be described below, the PWM generator system 329 is a two-phase center-aligned PWM generator.

[0290] The frequency divider 330 , the multiplexer 331 , and the DLL 332 are implemented in digital logic components (eg, transistors, logic gates, etc.) within the digital core 316 .

[0291] In the examples of the present disclosure, the frequency range covered by the oscillator 315 and the PWM generator system 329 is 20kHz to 5MHz or 20kHz to 40kHz, preferably 26kHz. The frequency accuracy of the PWM generator system 329 is ±1%, and the temperature difference is ±1%. In today's IC market, there is no IC that can provide an embedded oscillator and a two-phase center-aligned PWM generator with a frequency range of 20kHz to 5MHz. In fact, some examples of the present disclosure of IC can provide a frequency range of 20kHz up to 105MHz.

[0292] The oscillator 315 generates a master clock signal (clk_m) at a frequency of 20kHz to 5MHz or 20kHz to 40kHz, preferably 26kHz. The master clock clk_m is input to a frequency divider 330, which divides the frequency of the master clock clk_m by one or more predetermined division amounts. In this example, the frequency divider 330 divides the frequency of the master clock clk_m by 2, 4, 8, and 16, and provides the divided clock as an output to a multiplexer 331. The multiplexer 331 multiplexes the divided clock and provides the divided output to the DLL 332. This signal passed to the DLL 332 is a frequency reference signal, which controls the DLL 332 to output a signal at a desired frequency. In other examples, the frequency divider 330 and the multiplexer 331 are omitted.

[0293] The oscillator 315 also generates two phases: a first phase clock signal Phase 1 and a second phase clock signal Phase 2. The phases of the first phase clock signal and the second phase clock signal are center aligned. Fig.21 As shown:

[0294] The first phase clock signal Phase 1 is high for a variable time in the positive half cycle of clk_m and low during the negative half cycle of clk_m.

[0295] The second phase clock signal Phase 2 is high for a variable time in the negative half cycle of clk_m and low during the positive half cycle of clk_m.

[0296] Phase 1 and Phase 2 are then sent to DLL 332, which generates a dual-frequency clock signal using the first phase clock signal Phase 1 and the second phase clock signal Phase 2. The dual-frequency clock signal is twice the frequency of the main clock signal clk_m. In this example, an OR gate within DLL 332 generates a dual-frequency clock signal using the first phase clock signal Phase 1 and the second phase clock signal Phase 2. The dual-frequency clock or the divided frequency from the divider 330 is selected based on the selected target frequency and then used as a reference for DLL 332.

[0297] Within DLL 332, the signal hereinafter referred to as "clock" represents the master clock clk_m multiplied by 2, while the signal hereinafter referred to as "clock_del" is a copy of the clock delayed by one cycle of the frequency. Clock and clock_del pass through a phase frequency detector. Node Vc is then charged or discharged based on the phase error polarity by a charge pump. The control voltage is directly fed to control the delay of each delay unit within DLL 332 until the total delay of DLL 332 is exactly one cycle.

[0298] The DLL 332 controls the rising edges of the first-phase clock signal Phase 1 and the second-phase clock signal Phase 2 to be synchronized with the rising edge of the dual-frequency clock signal. The DLL 332 adjusts the frequencies and duty cycles of the first-phase clock signal Phase 1 and the second-phase clock signal Phase 2 in response to the corresponding frequency reference signal and the duty cycle control signal to generate the first-phase output signal Phase A and the second-phase output signal Phase B, thereby driving the H-bridge or the inverter to generate an AC drive signal to drive the ultrasonic transducer.

[0299] The PMIC 300 includes a first phase output signal terminal PHASE_A outputting a first phase output signal Phase A to the H-bridge circuit and a second phase output signal terminal PHASE_B outputting a second phase output signal Phase B to the H-bridge circuit.

[0300] In this example, the DLL 332 adjusts the duty cycle of the first phase clock signal Phase 1 and the second phase clock signal Phase 2 in response to the duty cycle control signal by changing the delay of each delay line in the DLL 332 in response to the duty cycle control signal.

[0301] The clock is used at twice its frequency because this ensures better accuracy. Fig. 22As shown, for the purpose of explanation, if the frequency of the master clock clk_m is used (which is not the case in the example of the present disclosure), Phase A is synchronized with the rising edge R of the clock, while Phase B is synchronized with the falling edge F of the clock. The delay line of DLL 332 controls the rising edge R, so for the falling edge F, the PWM generator system 329 would need to rely on perfect matching of the delay cells of DLL 332, which may not be perfect. However, to eliminate this error, the PWM generator system 329 uses a dual-frequency clock so that both Phase A and Phase B are synchronized with the rising edge R of the dual-frequency clock.

[0302] In order to implement a duty cycle from 20% to 50% in 2% steps, the delay line of DLL 332 includes 25 delay cells, where the output of each corresponding delay cell represents Phase nth. Ultimately, the phase of the output of the final delay cell will correspond to the input clock. Considering that all delays are almost the same, a specific duty cycle is obtained using the output of a specific delay cell and simple logic in the digital core 316.

[0303] It is important to pay attention to the startup of DLL 332 because DLL 332 may not lock on one delay cycle, but lock on two or more cycles, thereby bringing DLL 332 into a non-convergence region. To avoid this problem, a startup circuit is implemented in PWM generator system 329 that allows DLL 332 to start from a known and determined condition. The startup circuit also allows DLL 332 to start with minimal delay.

[0304] In the example of the present disclosure, the frequency range covered by the PWM generator system 329 is extended, so the delay cells in the DLL 332 can provide delays of 4 ns (for an oscillator frequency of 5 MHz) to 400 ns (for an oscillator frequency of 50 kHz). To accommodate these different delays, capacitor Cb is included in the PWM generator system 329, where the capacitor value is selected to provide the desired delay.

[0305] Phase A and Phase B are output from the DLL 332 and delivered to the bridge IC 301 through the digital IO, so that Phase A and Phase B can be used to control the operation of the bridge IC 301 .

[0306] The analog-to-digital converter (ADC) 318 will now be described in greater detail. The inventors had to overcome significant technical challenges to integrate the ADC 318 with the high speed oscillator 315 within the PMIC 300. Furthermore, integrating the ADC 318 within the PMIC 300 goes against conventional approaches in the art, which rely on using one of the many discrete ADC devices available in the IC market.

[0307] In this example, the ADC 318 samples at least one parameter within the ultrasonic transducer driver chip (PMIC 300) at a sampling rate equal to the frequency of the master clock signal clk_m. In this example, the ADC 318 is a 10-bit analog-to-digital converter that is capable of offloading digital sampling from the microprocessor 303 to save resources of the microprocessor 303. Integrating the ADC 318 within the PMIC 300 also avoids the need to use an I2C bus, which would otherwise slow down the sampling capabilities of the ADC (conventional devices rely on the I2C bus to transfer data between a dedicated discrete ADC and a microcontroller at a limited clock speed, typically up to 400kHz).

[0308] In examples of the present disclosure, the ADC 318 may sequentially sample one or more of the following parameters:

[0309] i. An rms current signal received at the ultrasonic transducer driver chip (PMIC 300) from an external inverter circuit driving the ultrasonic transducer. In this example, this parameter is the root mean square (rms) current reported by the bridge IC 301. Sensing the rms current is important for implementing a feedback loop for driving the ultrasonic transducer 215. Since the ADC 318 does not rely on this information being transmitted via the I2C bus, the ADC 318 is able to sense the rms current directly from the bridge IC 301 via the signal with little or no hysteresis.

[0310] This provides significant speed and accuracy benefits compared to conventional devices that are constrained by the relatively slow speed of the I2C bus.

[0311] ii. The voltage of the power supply connected to the PMIC 300 .

[0312] iii. A temperature signal, such as a temperature signal indicative of the chip temperature of the PMIC 300. As described above, the temperature can be measured very accurately because the temperature sensor 314 is embedded in the same IC as the oscillator 315. For example, if the PMIC 300 temperature rises, the PMIC 300 adjusts the current, frequency, and PWM to control the transducer oscillation, thereby controlling the temperature.

[0313] iv. Two external pins.

[0314] v. External NTC temperature sensor to monitor the temperature near the system.

[0315] In some examples, ADC 318 samples one or more of the above sources sequentially, such as in a round robin scheme.ADC 318 samples the sources at a high speed, such as the speed of oscillator 315, which may be 20 kHz to 5 MHz.

[0316] In some examples, the device 202 is configured so that a user or manufacturer of the device can specify how many samples should be collected from each source for averaging. For example, a user can configure the system to collect 512 samples from the rms current input, 64 samples from the battery voltage, 64 samples from the charger input voltage, 32 samples from the external pin, and 8 samples from the NTC pin. In addition, the user can also specify whether one of the above sources should be skipped.

[0317] In some examples, for each source, the user can specify two digital thresholds that divide the entire range into multiple zones, such as 3. The user can then set the system to release an interrupt when the sampled value changes zones (e.g., from zone 2 to zone 3).

[0318] No conventional IC available in the market today can perform the above-described features of the PMIC 300. When driving the ultrasound transducer 215, sampling with such flexibility and granularity is of utmost importance.

[0319] In this example, PMIC 300 includes 8-bit general purpose digital input and output ports (GPIO). Each port can be configured as a digital input terminal and a digital output terminal. Some ports have analog input functions, such as Fig.23 As shown in the table.

[0320] The GPIO7-GPIO5 ports of the PMIC 300 can be used to set the device address on the communication (I2C) bus 302. Subsequently, eight identical devices can be used on the same I2C bus. This is a unique feature in the IC industry because it allows eight identical devices to be used on the same I2C bus without any conflicting addresses. This is achieved by each device reading the state of GPIO7-GPIO5 during the first 100 μs after the PMIC 300 starts up and storing this partial address inside the PMIC 300. After the PMIC 300 has started up, the GPIOs can be used for any other purpose.

[0321] As described above, the PMIC 300 includes a six-channel LED driver 320. In this example, the LED driver 320 includes a 5V tolerant N-channel metal oxide semiconductor (NMOS) current source. The LED driver 320 is configured to set the LED current to four discrete levels; 5mA, 10mA, 15mA, and 20mA. The LED driver 320 is configured to dim each LED channel using a 12-bit PWM signal with or without gamma correction. The LED driver 320 is configured to change the PWM frequency from 300Hz to 1.5kHz.

[0322] In this example, the PMIC 300 includes two independent 6-bit digital-to-analog converters (DACs) 327, 328 incorporated into the PMIC 300. The purpose of the DACs 327, 328 is to output an analog voltage to manipulate the feedback path of an external regulator (e.g., a DC-DC boost converter 305, a buck converter, or an LDO). In addition, in some examples, the DACs 327, 328 can also be used to dynamically adjust the overcurrent shutdown level of the bridge IC 301, as described below.

[0323] The output voltage of each DAC 327, 328 can be programmed between 0V and 1.5V or between 0V and V_battery (Vbat). In this example, control of the DAC output voltage is accomplished via I2C commands. Combining two DACs in the PMIC 300 is unique and will allow dynamic monitoring control of current. If either of the DACs 327, 328 is an external chip, the speed will also be subject to the same constraints due to the speed limitations of the I2C protocol. If all of these embedded features are in the PMIC, the active power monitoring arrangement of the device 202 works at optimal efficiency. If they are external components, the active power monitoring arrangement will be completely inefficient.

[0324] Now refer to the accompanying drawings Fig.24 , the bridge IC 301 is a microchip that includes an embedded power switch circuit 333. In this example, the power switch circuit 333 is an H bridge 334, which Fig.25 However, it should be understood that other examples of bridge IC 301 may incorporate alternative power switching circuits to H-bridge 334 as long as the power switching circuits perform an equivalent function for generating an AC drive signal to drive ultrasonic transducer 215.

[0325] The bridge IC 301 includes a first phase terminal PHASE A receiving a first phase output signal PhaseA from a PWM signal generator subsystem of the PMIC 300 . The bridge IC 301 also includes a second phase terminal PHASE B receiving a second phase output signal PhaseB from the PWM signal generator subsystem of the PMIC 300 .

[0326] The bridge IC 301 includes a current sensing circuit 335 that directly senses the current in the H-bridge 334 and provides an RMS current output signal via the RMS_CURR pin of the bridge IC 301. The current sensing circuit 335 is configured for overcurrent monitoring to detect when the current flowing in the H-bridge 334 is above a predetermined threshold. The power switch circuit 333 including the H-bridge 334 and the current sensing circuit 335 are all integrated within the same embedded circuit of the bridge IC 301, which is a unique combination on the IC market. Currently, no other integrated circuit on the IC market includes an H-bridge with an embedded circuit for sensing the RMS current flowing through the H-bridge.

[0327] The bridge IC 301 includes a temperature sensor 336 that includes over-temperature monitoring. The temperature sensor 336 is configured to shut down the bridge IC 336 or disable at least a portion of the bridge IC 301 if the temperature sensor 336 detects that the bridge IC 301 is operating at a temperature above a predetermined threshold. Thus, the temperature sensor 336 provides an integrated safety function that prevents damage to the bridge IC 301 or other components within the transducer driver 202 if the bridge IC 301 is operating at an excessively high temperature.

[0328] The bridge IC 301 includes a digital state machine 337 integrally connected to the power switch circuit 333. The digital state machine 337 receives the phase A and phase B signals from the PMIC 300 and, for example, an ENABLE signal from the microcontroller 303. The digital state machine 337 generates a timing signal based on the first phase output signal Phase A and the second phase output signal Phase B.

[0329] The digital state machine 337 outputs timing signals corresponding to the phase A and phase B signals and the BRIDGE PR and BRIDGE EN signals to the power switch circuit 333 so as to control the power switch circuit 333. Therefore, the digital state machine 337 outputs timing signals to the switches T of the H bridge circuit 334. 1 To T 4 To control the switch T 1 To T 4 Switching on and off in sequence causes the H-bridge circuit to output an AC drive signal to drive the ultrasonic transducer 215 .

[0330] As described in more detail below, the switching sequence includes a free floating period during which the first switch T 1 and the second switch T 1 The third switch T is disconnected 3 and the fourth switch T 4Switched on to dissipate the energy stored by the ultrasonic transducer 215 .

[0331] The bridge IC 301 includes a test controller 338 that enables the bridge IC 301 to be tested to determine whether the embedded components within the bridge IC 301 are operating correctly. The test controller 338 is coupled to the TEST_DATA, TEST_CLK, and TEST_LOAD pins so that the bridge IC 301 can be connected to an external control device that feeds data into and out of the bridge IC 301 to test the operation of the bridge IC 301. The bridge IC 301 also includes a test bus that enables the digital communication bus within the bridge IC 301 to be tested via the TST_PAD pin.

[0332] The bridge IC 301 includes a power-on reset circuit (POR) 339, which controls the startup operation of the bridge IC 301. The POR 339 ensures that the bridge IC 301 starts up properly only when the power supply voltage is within a predetermined range. If the power supply voltage is outside the predetermined range, for example, if the power supply voltage is too high, the POR 339 delays the startup of the bridge IC 301 until the power supply voltage is within the predetermined range.

[0333] The bridge IC 301 includes a reference block (BG) 340 that provides an accurate reference voltage used by other subsystems of the bridge IC 301 .

[0334] The bridge IC 301 includes a current reference 341 that provides accurate current to the power switch circuit 333 and / or other subsystems within the bridge IC 301 , such as the current sensor 335 .

[0335] The temperature sensor 336 continuously monitors the temperature of the silicon of the bridge IC 301. If the temperature exceeds a predetermined temperature threshold, the power switch circuit 333 is automatically shut off. In addition, the over-temperature can be reported to an external host to notify the external host that an over-temperature event has occurred.

[0336] A digital state machine (FSM) 337 generates a timing signal for the power switch circuit 333 , which in this example is a timing signal for controlling an H-bridge 334 .

[0337] The bridge IC 301 includes comparators 342 , 343 that compare signals from various subsystems of the bridge IC 301 with voltage and current references 340 , 341 and provide reference output signals via pins of the bridge IC 301 .

[0338] See again the attached figure Fig.25, the H-bridge 334 of this example includes four switches in the form of NMOS field effect transistor (FET) switches on both sides of the H-bridge 334. The H-bridge 334 includes four switches or transistors T connected in an H-bridge configuration. 1 To T 4 , where each transistor T 1 To T 4 Driven by the corresponding logic input terminals A to D. Transistor T 1 To T 4 is configured to be driven by a bootstrap voltage, which is obtained by using Fig.25 The two external capacitors Cb connected as shown are generated internally.

[0339] H-bridge 334 includes various power inputs and outputs connected to corresponding pins of bridge IC 301. H-bridge 334 receives a programmable voltage VBOOST via a first power supply terminal (at Fig.25 The H-bridge 334 includes a second power supply terminal (at Fig.25 VSS_P in the .

[0340] The H-bridge 334 includes output terminals OUTP, OUTN, which are configured to be connected to corresponding terminals of the ultrasonic transducer 215 , so that the AC driving signal output from the H-bridge 334 can drive the ultrasonic transducer 215 .

[0341] Four switches or transistors T 1 To T 4 The switching of is controlled by the switching signal issued by the digital state machine 337 via the logic input terminals A to D. It should be understood that although Fig.25 Four transistors T are shown 1 To T 4 , but in other examples, the H-bridge 334 incorporates a larger number of transistors or other switching components to implement the functionality of the H-bridge.

[0342] In this example, the H-bridge 334 operates at a switching power of 22 W to 50 W in order to deliver an AC drive signal having sufficient power to optimally drive the ultrasonic transducer 215 at or near the resonant frequency of the ultrasonic transducer 215. The voltage switched by the H-bridge 334 of this example is ±15 V. In other examples, the voltage is ±20 V.

[0343] Other voltages and power ratings of the H-bridge 334 are contemplated and will be selected based on the intended purpose. In some examples, the voltage switched by the H-bridge 334 of this example is 100V-500V with a power output of 200W-2500W.

[0344] In this example, the H-bridge 334 switches at a frequency of 20kHz to 40kHz, preferably 26kHz. Except for the bridge IC 301 described herein, conventional integrated circuit H-bridges available on the IC market cannot operate at a power of 22V to 50V in the frequency range of 26kHz to 5MHz.

[0345] Now refer to the accompanying drawings Fig.26 , the current sensor 335 includes positive and negative current sensing resistors RshuntP, RshuntN connected in series with the respective high and low sides of the H bridge 334, as shown in FIG. Fig.25 As shown. The current sensing resistors RshuntP, RshuntN are low value resistors, which are 0.1Ω in this example. The current sensor 335 includes a first voltage sensor in the form of a first operational amplifier 344, which measures the voltage drop across the first current sensor resistor RshuntP and a second voltage sensor in the form of a second operational amplifier 345, the first operational amplifier measuring the voltage drop across the first current sensor resistor RshuntP, and the second operational amplifier measuring the voltage drop across the second current sensor resistor RshuntN. In this example, the gain of each operational amplifier 344, 345 is 2V / V. In this example, the output of each operational amplifier 344, 345 is 1mA / V. The current sensor 335 includes a pull-down resistor Rcs, which is 2kΩ in this example. The output of the operational amplifiers 344, 345 provides an output CSout, which passes through a low pass filter 346, which removes transients in the signal CSout. The output Vout of the low pass filter 346 is the output signal of the current sensor 335.

[0346] The current sensor 335 thus measures the AC current flowing through the H-bridge 334 and the ultrasonic transducer 215, respectively. The current sensor 335 converts the AC current into an equivalent RMS output voltage (Vout) relative to ground. The current sensor 335 has a high bandwidth capability because the H-bridge 334 can operate at a frequency of 26kHz to 5MHz, preferably 20kHz to 40kHz, preferably 26kHz. The output Vout of the current sensor 335 reports a positive voltage that is equal to the measured AC rms current flowing through the ultrasonic transducer 215. In this example, the output voltage Vout of the current sensor 335 is fed back to the control circuit within the bridge IC 301 so that the bridge IC 301 can shut down the H-bridge 334 if the current flowing through the H-bridge 334 and thus the transducer 215 exceeds a predetermined threshold. Furthermore, the over-current threshold event is reported to the first comparator 342 in the bridge IC 301 , so that the bridge IC 301 can report the over-current event via the OVC_TRIGG pin of the bridge IC 301 .

[0347] Now refer to the accompanying drawings Fig. 27 , the control of the H-bridge 334 will now also be described with reference to the equivalent piezoelectric model of the ultrasonic transducer 215 .

[0348] In order to generate a positive voltage at the output terminals OUTP and OUTN of the H bridge 334, as shown in FIG. Fig. 27 As indicated by V_out in (note the direction of the arrow), transistor T 1 To T 4 The switching sequence via inputs A to D is as follows:

[0349] 1. Positive output voltage on ultrasonic transducer 215: A-on, B-off, C-off, D-on

[0350] 2. Transition from positive output voltage to zero: A - Off, B - Off, C - Off, D - On. During this transition, if there is a switching error or delay in A, C is turned off first to minimize or avoid power loss by minimizing or avoiding current flowing through A and C.

[0351] 3. Zero output voltage: A-off, B-off, C-on, D-on. During this zero output voltage phase, the output terminals OUTP, OUTN of the H-bridge 334 are grounded through the C and D switches that remain on. This dissipates the energy stored by the capacitor in the equivalent circuit of the ultrasonic transducer, thereby minimizing the voltage overshoot in the switching waveform voltage applied to the ultrasonic transducer.

[0352] 4. Transition from zero to negative output voltage: A-off, B-off, C-on, D-off.

[0353] 5. Negative output voltage on ultrasonic transducer 215: A - OFF, B - ON, C - ON, D - OFF.

[0354] At high frequencies of 2 MHz to 5 MHz, it will be appreciated that the time for each portion of the switching sequence is very short, on the order of nanoseconds or picoseconds.

[0355] In the attached figure Fig.28 A graph showing the output voltages OUTP, OUTN generated by the H-bridge 334 according to the switching sequence described above is shown in FIG. The zero output voltage portion of the switching sequence is included to accommodate the energy stored by the ultrasonic transducer 215 (e.g., the energy stored by the capacitor in the equivalent circuit of the ultrasonic transducer). As described above, this minimizes the voltage overshoot in the switching waveform voltage applied to the ultrasonic transducer, and thus minimizes unnecessary power dissipation and heating in the ultrasonic transducer.

[0356] Minimizing or removing voltage overshoots can also prevent transistors from being subjected to voltages exceeding their rated voltages, thereby reducing the risk of damage to transistors in the bridge IC 301. In addition, minimizing or removing voltage overshoots enables the bridge IC 301 to accurately drive the ultrasonic transducer in a manner that minimizes disruption to the current sensing feedback loop described herein. Thus, the bridge IC 301 can drive the ultrasonic transducer at a power of 22 W to 50 W or 70 W. In some examples, the bridge IC 301 can drive the ultrasonic transducer at a frequency of 20 kHz to 5 MHz. In other examples, the bridge IC 301 can drive the ultrasonic transducer at a frequency of 20 kHz to 40 kHz.

[0357] The bridge IC 301 of this example is configured to be controlled by the PMIC 300 to operate in two different modes (referred to herein as forced mode and natural frequency mode). These two operating modes are novel compared to existing bridge ICs. In particular, the natural frequency mode is a major innovation that provides significant benefits in terms of accuracy and efficiency in driving ultrasonic transducers compared to conventional devices.

[0358] Forced Frequency Mode (FFM)

[0359] In forced frequency mode, the H-bridge 334 is controlled in the above sequence but at a user-selectable frequency. Thus, regardless of the natural resonant frequency of the ultrasonic transducer 215, the H-bridge transistors T 1 To T 4 to switch the output voltage on the ultrasonic transducer 215. Therefore, the forced frequency mode allows the H-bridge 334 to drive the ultrasonic transducer 215 having the resonant frequency f1 at a different frequency f2.

[0360] In order to adapt the operation to different applications, it may be appropriate to drive the ultrasonic transducer at a frequency different from its resonant frequency. For example, it may be appropriate to drive the ultrasonic transducer at a frequency slightly off the resonant frequency (for mechanical reasons, to prevent mechanical damage to the transducer). Alternatively, it may be appropriate to drive the ultrasonic transducer at a low frequency, but the ultrasonic transducer has a different natural resonant frequency due to its size.

[0361] The transducer driver 202 controls the bridge IC 301 to drive the ultrasonic transducer 215 in a forced frequency mode in response to the configuration of the transducer driver 202 for a particular application or a particular ultrasonic transducer.

[0362] Natural Frequency Mode (NFM)

[0363] The following natural frequency operating mode is a significant development and provides benefits in terms of improved precision and efficiency compared to conventional ultrasonic drivers available in the IC market today.

[0364] The natural frequency mode of operation follows the same switching sequence as described above, but the timing of the zero output portion of the sequence is adjusted to minimize or avoid problems that may arise due to current spikes in forced frequency mode operation. These current spikes occur when the voltage on the ultrasonic transducer 215 is switched to its opposite voltage polarity. An ultrasonic transducer comprising a piezoelectric crystal has an equivalent circuit incorporating a capacitor connected in parallel (e.g., see Fig. 27 If the voltage on the ultrasonic transducer is hard switched from positive to negative, a large amount of current will be generated as the energy stored in the capacitor is dissipated due to the high dV / dt.

[0365] The natural frequency mode avoids hard switching the voltage on the ultrasonic transducer 215 from a positive voltage to a negative voltage (and vice versa). Instead, the ultrasonic transducer 215 (piezoelectric crystal) is free-floating before the reverse voltage is applied, with zero voltage applied to its terminals during the free-floating period. The PMIC 300 sets the driving frequency of the bridge IC 301 so that the bridge 334 sets the free-floating period so that the current inside the ultrasonic transducer 215 (due to the energy stored in the piezoelectric crystal) reverses the voltage on the terminals of the ultrasonic transducer 215 during the free-floating period.

[0366] Therefore, when the H-bridge 334 applies a negative voltage at the terminals of the ultrasonic transducer 215, the ultrasonic transducer 215 (the capacitor in the equivalent circuit) has been reverse charged and no current spike occurs because there is no high dV / dt.

[0367] However, it should be understood that when the ultrasonic transducer 215 is first activated, the charge within the ultrasonic transducer 215 (piezoelectric crystal) requires time to accumulate. Therefore, the ideal situation in which the energy within the ultrasonic transducer 215 will reverse the voltage during the free floating period only occurs after the oscillation within the ultrasonic transducer 215 has accumulated charge. To accommodate this, when the bridge IC 301 first activates the ultrasonic transducer 215, the PMIC 300 controls the power delivered to the ultrasonic transducer 215 through the H-bridge 334 to a first value that is a low value (e.g., 5V). The PMIC 300 then controls the power delivered to the ultrasonic transducer 215 through the H-bridge 334 to increase to a second value (e.g., 15V) that is higher than the first value over a period of time in order to accumulate the energy stored in the ultrasonic transducer 215. Current spikes will still occur during this oscillation ramp until the current inside the ultrasonic transducer 215 is generated sufficiently. However, by using a low first voltage at startup, those current spikes are kept low enough to minimize the impact on the operation of the ultrasonic transducer 215 .

[0368] To achieve the natural frequency mode, the transducer driver 202 controls the frequency of the oscillator 315 and the duty cycle (ratio of on time to free floating time) of the AC drive signal output from the H-bridge 334 with high precision. In this example, the transducer driver 202 implements three control loops to adjust the oscillator frequency and duty cycle so that the voltage reversal at the terminals of the ultrasonic transducer 215 is as precise as possible and the current spikes are minimized or avoided as much as possible. The use of control loops to accurately control the oscillator and duty cycle is a major advance in the field of IC ultrasonic drivers.

[0369] During the natural frequency operation mode, the current sensor 335 senses the current flowing through the ultrasonic transducer 215 during the free floating period. When the current sensor 335 senses that the current flowing through the ultrasonic transducer 215 during the free floating period is zero, the digital state machine 337 adjusts the timing signal to turn on the first switch T1 or the second switch T2.

[0370] In the attached figure Fig.29 An oscillator voltage waveform 347 (V(osc)), a switching waveform 348 resulting from turning on and off the left-hand high switch T1 of the H-bridge 334, and a switching waveform 349 resulting from turning on and off the right-hand high switch T2 of the H-bridge 334 are shown. For the intervening free-floating period 350, both high switches T1, T2 of the H-bridge 334 are turned off (free-floating phase). The duration of the free-floating period 350 is controlled by the magnitude of the free-floating control voltage 351 (Vphioff).

[0371] In the attached figure Fig.30 A voltage waveform 352 is shown at a first terminal of the ultrasonic transducer 215 (which is inverted at a second terminal of the ultrasonic transducer 215) and a piezoelectric current 353 flowing through the ultrasonic transducer 215. The piezoelectric current 353 represents a (nearly) ideal sinusoidal waveform (which is never possible in forced frequency mode or in any bridge on the IC market).

[0372] Before the sine wave of the piezoelectric current 353 reaches zero, the left high switch T1 of the H-bridge 334 is turned off (here, the switch T1 is turned off when the piezoelectric current 353 is about 6A). The remaining piezoelectric current 353 flowing in the ultrasonic transducer 215 due to the energy stored in the ultrasonic transducer 215 (the capacitor of the piezoelectric equivalent circuit) is responsible for the voltage reversal during the free floating period 350. The piezoelectric current 353 decays to zero during the free floating period 350 and enters the negative current domain thereafter. The terminal voltage at the ultrasonic transducer 215 drops from the power supply voltage (19V in this case) to less than 2V, and the drop stops when the piezoelectric current 353 reaches zero. This is the best time to turn on the low side switch T3 of the H-bridge 334 in order to minimize or avoid current spikes.

[0373] Compared with the above forced frequency modes, the natural frequency modes have at least three advantages:

[0374] 1. The current spikes associated with hard switching of package capacitors are significantly reduced or completely avoided.

[0375] 2. Power loss due to hard switching is virtually eliminated.

[0376] 3. The frequency is regulated by the control loop and will remain close to the resonance of the piezoelectric crystal (ie, the natural resonant frequency of the piezoelectric crystal).

[0377] In the case of adjusting the frequency by the control loop (advantage 3 above), the PMIC 300 first controls the bridge IC 301 to drive the ultrasonic transducer 215 at a frequency higher than the resonance of the piezoelectric crystal. The PMIC 300 then controls the bridge IC 301 so that the frequency of the AC drive signal is attenuated / reduced during startup. Once the frequency approaches the resonance frequency of the piezoelectric crystal, the piezoelectric current is rapidly generated / increased. Once the piezoelectric current is large enough to cause the desired voltage reversal, the PMIC 300 stops the frequency attenuation / reduction. The control loop of the PMIC 300 then takes over the adjustment of the frequency and duty cycle of the AC drive signal.

[0378] In forced frequency mode, the power delivered to the ultrasonic transducer 215 is controlled by duty cycle and / or frequency shift and / or by changing the supply voltage. However, in this example, in natural frequency mode, the power delivered to the ultrasonic transducer 215 is controlled only by the supply voltage.

[0379] In this example, during the setup phase of operation of the transducer driver, the bridge IC 301 is configured to measure the current flowing between the first switch T 1 and the second switch T 2 The third switch T is disconnected and 3 and the fourth switch T 4 The length of time it takes for the current flowing through the ultrasonic transducer 215 to drop to zero when switched on. The bridge IC 301 then sets the length of time of the free floating period to be equal to the measured length of time.

[0380] Now refer to the accompanying drawings Fig.31 , the PMIC 300 and bridge IC 301 of this example are designed to work together as a companion chipset. The PMIC 300 and bridge IC 301 are electrically connected together to communicate with each other. In this example, there is an interconnect between the PMIC 300 and the bridge IC 301, thereby enabling the following two categories of communication:

[0381] 1. Control signal

[0382] 2. Feedback signal

[0383] The connections between the PHASE_A and PHASE_B pins of the PMIC 300 and the bridge IC 301 carry the PWM modulated control signals that drive the H-bridge 334. The connections between the EN_BR pin of the PMIC 300 and the bridge IC 301 carry the EN_BR control signal that triggers the start-up of the H-bridge 334. The timing between the PHASE_A, PHASE_B, and EN_BR control signals is important and is handled by the digital bridge control of the PMIC 300.

[0384] The connections between the CS, OC, and OT pins of the PMIC 300 and the bridge IC 301 transmit CS (current sense), OC (over current), and OT (over temperature) feedback signals from the bridge IC 301 back to the PMIC 300. Most notably, the CS (current sense) feedback signal includes a voltage comparable to the rms current flowing through the ultrasonic transducer 215, which is measured by the current sensor 335 of the bridge IC 301.

[0385] The OC (overcurrent) and OT (overtemperature) feedback signals are digital signals indicating that the bridge IC 301 has detected an overcurrent or overvoltage event. In this example, external resistors are used to set the thresholds for overcurrent and overtemperature. Alternatively, these thresholds can also be set dynamically in response to a signal passed from one of the two DAC channels VDAC0, VDAC1 from the PMIC 300 to the OC_REF pin of the bridge IC 301.

[0386] In this example, the design of the PMIC 300 and the bridge IC 301 allows the pins of the two integrated circuits to be directly connected to each other (e.g., via copper traces on a PCB), so that there is little or no lag in the signal communication between the PMIC 300 and the bridge IC 301. This provides a significant speed advantage over conventional bridges on the IC market, which are typically controlled by signals via a digital communication bus. For example, the standard I2C bus is only clocked at 400kHz, which is too slow to transmit data sampled at a high clock speed of 2MHz to 5MHz.

[0387] Although examples of the present disclosure have been described above with respect to microchip hardware, it should be understood that other examples of the present disclosure include methods of operating components and subsystems of each microchip to perform the functions described herein, such as methods of operating PMIC 300 and bridge IC 301 in forced frequency mode or natural frequency mode.

[0388] The operation of some example system 1 will now be described. More specifically, the following process sequence is performed by system 1 to optimize the production of hydrogen generated by system 1:

[0389] 1. The system is activated and the master controller coordinates the electrolysis reaction and control of the transducer driver 202.

[0390] 2. Each transducer driver 202 sequentially drives the corresponding ultrasonic transducer 215 at multiple drive frequencies to detect the optimal (resonant) frequency at which the ultrasonic transducer 215 most efficiently converts electrical energy into kinetic energy. At resonance, the ultrasonic transducer 215 converts the maximum active power into kinetic energy. The transducer driver 202 then drives the ultrasonic transducer 215 at the optimal (resonant) frequency to effectively emit ultrasonic waves that cause agitation and / or cavitation in the aqueous solution 102.

[0391] 3. The main controller 2 monitors the hydrogen pressure signal and / or the oxygen pressure to detect the volume or rate of hydrogen and / or oxygen generated by the system 1.

[0392] 4. If the volume or rate of hydrogen and / or oxygen generated by the system 1 is lower than the expected or optimal amount, the main controller 2 controls the power controller to increase the power (potential difference) on the cathode 105 and the anode 107. Otherwise, the power (potential difference) between the cathode 105 and the anode 107 remains unchanged.

[0393] 5. If the main controller 2 controls the power controller to increase the power (potential difference) on the cathode 105 and the anode 107, and there is no change in the production rate of hydrogen and / or oxygen, the main controller 2 controls each transducer controller 202 to increase the power of the driving signal of the ultrasonic transducer, thereby increasing the intensity of the ultrasonic waves in the reaction vessel 101.

[0394] 6. If the production rate of hydrogen and / or oxygen increases, maintain the new parameters (power on the anode / cathode and power of the ultrasonic transducer drive signal), otherwise, repeat steps 4 and 5 until the expected or optimal production rate of hydrogen and / or oxygen is reached.

[0395] 7. If after x iterations of step 6, the production rate of hydrogen and / or oxygen has not increased, the last set of parameters is maintained.

[0396] 8. If the production rate of hydrogen and / or oxygen starts to drop with maximum power input (on the anode / cathode and / or in the ultrasonic transducer drive signal), the main controller 2 controls the power controller and each transducer driver 202 to gradually reduce the power of the system 1.

[0397] 9. Production is completed.

[0398] The volume of hydrogen produced by the systems of some examples of the present disclosure may be calculated as follows:

[0399] Stoichiometry of water electrolysis:

[0400]

[0401] Every 2 mol of water produces 2 mol of hydrogen.

[0402] 1 mol of water is 18 g (18 mL), and 1 mol of hydrogen is 4 g (4 mL).

[0403] For an inlet water flow rate of 10 L / h, the output hydrogen at 70% efficiency will be:

[0404]

[0405] The rate of hydrogen production is related to the flow rate of the input water (taking into account the efficiency of the system).

[0406] The formula for the output flow rate can be derived from the following formula:

[0407]

[0408] Where x is the inlet flow rate,

[0409] y is the efficiency of the system.

[0410] The system of the examples of the present disclosure does not require desalination of seawater before electrolysis. Seawater can be used directly as the electrolyte. The configuration of the transducer driver and the feedback loop determines and achieves the optimal balance between the frequency and intensity of the ultrasonic waves flowing through the electrolytic solution to maximize hydrogen production. In some examples, the transducer driver sets a frequency of 20kHz to 40kHz to produce the optimal balance of high electrolysis reaction rate. In some examples, the transducer driver sets 0.1wcm -2 -0.02wcm -2 The optimal balance of frequency and intensity to produce a high electrolysis reaction rate.

[0411] The features of several examples or embodiments are summarized above so that those of ordinary skill in the art can better understand the various aspects of the present disclosure. Those of ordinary skill in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to perform the same purpose and / or achieve the same advantages of the various examples or embodiments introduced herein. Those of ordinary skill in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and they can make various changes, substitutions and modifications herein without departing from the spirit and scope of the present disclosure.

[0412] Although the subject matter has been described in language specific to structural features or methodological acts, it should be understood that the subject matter of the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing at least some of the claims.

[0413] Various operations of examples or embodiments are provided herein. The order of describing some or all operations should not be interpreted as implying that these operations must be order-dependent. Thanks to this specification, alternative sequencing will be known. In addition, it should be understood that not all operations must be present in each embodiment provided herein. In addition, it should be understood that not all operations are necessary in some examples or embodiments.

[0414] In addition, "exemplary" is used herein to indicate that it is used as an example, instance, explanation, etc., and is not necessarily advantageous. As used in this application, "or" is intended to represent an inclusive "or", rather than an exclusive "or". In addition, "one" and "a kind" as used in this application and the appended claims are generally interpreted as meaning "one (kind) or more (kind)", unless otherwise specified or clearly known from the context that it is for a singular form. In addition, at least one of A and B, etc., generally refers to A or B, or both A and B. In addition, in terms of using "including", "having", "containing", "with" or its variants, such terms are intended to be inclusive in a manner similar to the term "comprising". In addition, unless otherwise specified, "first", "second", etc. are not intended to imply time, space, sorting, etc. On the contrary, such terms are merely used as identifiers, names, etc. of features, elements, projects, etc. For example, the first element and the second element generally correspond to element A and element B or two different or two identical elements or the same element.

[0415] In addition, although the present disclosure has been shown and described with respect to one or more specific implementations, other persons of ordinary skill in the art will think of equivalent changes and modifications based on the reading and understanding of this specification and the drawings. The present disclosure includes all such modifications and changes and is limited only by the scope of the following claims. In particular, with respect to the various functions performed by the above-mentioned features (e.g., elements, resources, etc.), unless otherwise indicated, the terms used to describe such features are intended to correspond to any feature that performs the specified function of the described features (e.g., functionally equivalent), even if it is not structurally equivalent to the disclosed structure. In addition, although specific features of the present disclosure may have been disclosed with respect to only one of several specific implementations, such features may be combined with one or more other features of other specific implementations, as may be desired and advantageous for any given or specific application.

[0416] Examples or implementations of the subject matter and functional operations described herein may be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in a combination of one or more of them.

[0417] Some examples or embodiments are implemented using one or more modules of computer program instructions encoded on a computer readable medium for execution by a data processing device or for controlling the operation of a data processing device. The computer readable medium may be a manufactured product, such as a hard drive in a computer system or embedded system. The computer readable medium may be acquired separately and then encoded with one or more modules of computer program instructions, such as by delivering one or more modules of computer program instructions over a wired or wireless network. The computer readable medium may be a machine readable storage device, a machine readable storage substrate, a memory device, or a combination of one or more of them.

[0418] The terms "computing device" and "data processing apparatus" encompass all devices, equipment and machines for processing data, including, by way of example, a programmable processor, a computer, or a plurality of processors or computers. In addition to hardware, the apparatus may also include code that creates an execution environment for the computer program in question, e.g., code constituting processor firmware, a protocol stack, a database management system, an operating system, a runtime environment, or a combination of one or more of these. Furthermore, the apparatus may employ a variety of different computing model infrastructures, such as web services, distributed computing, and grid computing infrastructures.

[0419] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output.

[0420] As an example, processors suitable for executing computer programs include both general-purpose and special-purpose microprocessors and any one or more processors of any kind of digital computer. Generally speaking, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally speaking, a computer will also include one or more mass storage devices (e.g., disks, magneto-optical disks, or optical disks) for storing data, or be operably coupled to receive data from one or more mass storage devices or to transfer data to one or more mass storage devices or both. However, a computer need not have such devices. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices.

[0421] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms should not be interpreted as excluding the presence of other features, steps or components.

[0422] The present invention may also broadly include parts, elements, steps, examples and / or features that are individually mentioned or indicated in the specification, or parts, elements, steps, examples and / or features that are commonly mentioned or indicated in the specification in any and all combinations of two or more of the parts, elements, steps, examples and / or features. Specifically, one or more features in any embodiment described herein may be combined with one or more features from any other embodiment described herein.

[0423] Protection may be sought for any feature disclosed in any one or more of the publications cited herein in conjunction with the present disclosure.

[0424] Although certain exemplary embodiments of the invention have been described, the scope of the appended claims is not intended to be limited to only these embodiments. The claims should be interpreted literally, objectively, and / or to encompass equivalents.

[0425] Representative features

[0426] Representative features are listed in the following clauses, which stand alone or can be combined in any combination with one or more features disclosed in the text and / or drawings of this specification.

[0427] 1. A system for generating hydrogen, the system comprising:

[0428] a reaction vessel containing an aqueous solution;

[0429] a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode;

[0430] an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source;

[0431] a polymer electrolyte membrane (PEM) positioned between the cathode and the anode to separate the H+ ions and the OH- ions in the aqueous solution, thereby creating a partitioned region in the reaction vessel, wherein the aqueous solution in the partitioned region proximate the cathode has a higher concentration of H+ ions than OH- ions;

[0432] a first ultrasonic transducer, the first ultrasonic transducer being at least partially positioned in the reaction vessel, the first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that the first ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode, thereby scavenging any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas;

[0433] a second ultrasonic transducer at least partially positioned in the reaction vessel, the second ultrasonic transducer being positioned at a predetermined distance from the anode and being oriented such that the second ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution to separate individual water molecules that are available to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen gas at the anode; and

[0434] a plurality of transducer drivers, each of which is electrically coupled to a corresponding one of the first ultrasonic transducer or the second ultrasonic transducer to drive the ultrasonic transducer to generate the ultrasonic wave, wherein the transducer driver comprises:

[0435] An H-bridge circuit connected to the ultrasonic transducer, wherein the H-bridge circuit generates an AC driving signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave;

[0436] A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising:

[0437] An oscillator that generates:

[0438] Master clock signal,

[0439] a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and

[0440] a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase;

[0441] A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising:

[0442] a delay locked loop, the delay locked loop using the first phase clock signal and the second phase clock signal to generate a dual-frequency clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop is synchronized with the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer;

[0443] a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit;

[0444] a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit;

[0445] a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the ultrasonic transducer with the AC drive signal;

[0446] An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising:

[0447] at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal so that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency that is proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal;

[0448] a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem;

[0449] A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising:

[0450] a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and

[0451] A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the ultrasonic transducer to control the cavitation in the aqueous solution in response to a feedback signal indicative of the operation of the ultrasonic transducer.

[0452] 2. A system for generating hydrogen, the system comprising:

[0453] a reaction vessel containing an aqueous solution;

[0454] a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode;

[0455] an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source;

[0456] a plurality of first ultrasonic transducers, the plurality of first ultrasonic transducers being at least partially positioned in the reaction vessel, each first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that each first ultrasonic transducer transmits and conducts ultrasonic waves through the aqueous solution at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode to scavenge any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas;

[0457] a plurality of second ultrasonic transducers, the plurality of second ultrasonic transducers being at least partially positioned in the reaction vessel, the second ultrasonic transducers being positioned at a predetermined distance from the anode and being oriented such that the second ultrasonic transducers transmit ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution to separate individual water molecules that can be used to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen gas at the anode; and

[0458] a plurality of transducer drivers, each of the plurality of transducer drivers being electrically coupled to a corresponding one of the ultrasonic transducers to drive the ultrasonic transducer to generate the ultrasonic wave, wherein each transducer driver comprises:

[0459] an H-bridge circuit connected to the corresponding one of the ultrasonic transducers, wherein the H-bridge circuit generates an AC drive signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave;

[0460] A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising:

[0461] An oscillator that generates:

[0462] Master clock signal,

[0463] a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and

[0464] a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase;

[0465] A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising:

[0466] a delay locked loop, the delay locked loop using the first phase clock signal and the second phase clock signal to generate a dual-frequency clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop is synchronized with the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer;

[0467] a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit;

[0468] a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit;

[0469] a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the corresponding one of the ultrasonic transducers with the AC drive signal;

[0470] An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising:

[0471] at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal so that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency that is proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal;

[0472] a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem;

[0473] A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising:

[0474] a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and

[0475] A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the corresponding one of the ultrasonic transducers in response to a feedback signal indicative of the operation of the corresponding one of the ultrasonic transducers to control the cavitation in the aqueous solution.

[0476] 3. A system according to clause 2, wherein the system comprises:

[0477] A polymer electrolyte membrane (PEM) is positioned between the cathode and the anode within the reaction vessel to separate the H+ ions and the OH- ions in the aqueous solution, thereby creating a separation region in the reaction vessel, wherein the aqueous solution in the separation region proximate the cathode has a higher concentration of H+ ions than OH- ions.

[0478] 4. A system according to any of the preceding clauses, wherein the transducer driver drives the ultrasonic transducer at a frequency of 20 kHz to 40 kHz.

[0479] 5. A system according to any of the preceding clauses, wherein each first ultrasonic transducer is positioned at a distance from the outer surface of the cathode, the distance corresponding to one wavelength of the ultrasonic wave emitted by the ultrasonic transducer.

[0480] 6. A system according to any of clauses 1 to 4, wherein each first ultrasonic transducer is positioned at a distance from the outer surface of the cathode, the distance corresponding to a plurality of wavelengths of the ultrasonic waves emitted by the ultrasonic transducer.

[0481] 7. A system according to any of the preceding clauses, wherein each second ultrasonic transducer is positioned at a distance from the outer surface of the anode, the distance corresponding to one wavelength of the ultrasonic wave emitted by the ultrasonic transducer.

[0482] 8. A system according to any of the preceding clauses, wherein each second ultrasonic transducer is positioned at a distance from the outer surface of the anode, the distance corresponding to a plurality of wavelengths of the ultrasonic waves emitted by the ultrasonic transducer.

[0483] 9. A system according to any of the preceding clauses, wherein each first ultrasonic transducer is oriented to transmit ultrasonic waves in a direction transverse to the longitudinal extent of the cathode.

[0484] 10. A system according to any of the preceding clauses, wherein each second ultrasonic transducer is oriented to transmit ultrasonic waves in a direction transverse to the longitudinal extent of the anode.

[0485] 11. A system according to any of the preceding clauses, wherein the system comprises:

[0486] A main controller controls power applied to the anode and the cathode, wherein the main controller is coupled to each transducer driver to control operation of each transducer driver to optimize efficiency of hydrogen generation.

[0487] 12. The system according to clause 11, wherein the system comprises:

[0488] a hydrogen collector, the hydrogen collector being at least partially positioned within the reaction vessel and configured to collect hydrogen generated within the reaction vessel; and

[0489] A hydrogen pressure sensor senses the hydrogen pressure in the hydrogen collector, and the hydrogen pressure sensor is electrically coupled to the main controller to provide a hydrogen pressure signal to the main controller in a feedback loop.

[0490] 13. A system according to clause 11 or clause 12, wherein the system comprises:

[0491] an oxygen collector, the oxygen collector being at least partially positioned within the reaction vessel for collecting oxygen generated within the reaction vessel; and

[0492] An oxygen pressure sensor senses oxygen pressure within the oxygen collector, the oxygen pressure sensor being electrically coupled to the main controller to provide an oxygen pressure signal to the main controller in a feedback loop.

[0493] 14. A system according to any of the preceding clauses, wherein the transducer driver comprises:

[0494] A frequency divider is connected to the oscillator to receive the master clock signal from the oscillator, the frequency divider divides the master clock signal by a predetermined division amount and outputs a frequency reference signal to the delay locked loop.

[0495] 15. The system of clause 14, wherein the delay locked loop comprises a plurality of delay lines connected end-to-end, wherein a total delay of the delay lines is equal to a period of the master clock signal.

[0496] 16. The system of clause 15, wherein the delay locked loop adjusts the duty cycle of the first phase clock signal and the second phase clock signal in response to the driver control signal by changing the delay of each delay line in the delay locked loop.

[0497] 17. A system according to any of the preceding clauses, wherein the feedback input terminal receives a feedback signal in the form of a voltage from the H-bridge circuit, the feedback signal being indicative of the rms current of the AC drive signal that is driving the ultrasonic transducer.

[0498] 18. A system according to any of the preceding clauses, wherein the ADC subsystem includes at least one additional ADC input terminal, which receives a feedback signal indicating at least one of the voltage of a battery connected to the system or the voltage of a battery charger connected to the system.

[0499] 19. A system for generating hydrogen, the system comprising:

[0500] a housing comprising a first interior chamber and a second interior chamber;

[0501] an anode positioned at least partially within the first interior chamber, a portion of the anode being in electrical contact with water within the first interior chamber to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the anode is porous;

[0502] a cathode positioned at least partially within the second interior chamber, wherein the cathode is porous, and wherein the cathode and the anode are configured to receive power from a power source;

[0503] a polymer electrolyte membrane (PEM) positioned between the cathode and the anode, wherein the PEM allows H+ ions to cross from the anode to the cathode and the PEM prevents OH- ions from crossing from the anode to the cathode;

[0504] an ultrasonic transducer positioned at least partially in the first interior chamber, the ultrasonic transducer positioned at a predetermined distance from the anode and oriented such that the ultrasonic transducer transmits ultrasonic waves at least partially toward a surface of the anode to induce cavitation in water proximate the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules to separate individual water molecules available to interact with the anode to carry out the oxidation reaction at the anode to oxidize OH- ions and form oxygen gas at the anode;

[0505] a transducer driver electrically coupled to the ultrasonic transducer to drive the ultrasonic transducer to generate the ultrasonic wave; and

[0506] A hydrogen outlet allows hydrogen gas to be generated in the second interior chamber as the H+ ions are reduced at the cathode to generate the hydrogen gas.

[0507] 20. The system according to clause 19, wherein the system further comprises:

[0508] A transducer driver coupled to the ultrasonic transducer, the transducer driver comprising:

[0509] An H-bridge circuit connected to the ultrasonic transducer, wherein the H-bridge circuit generates an AC driving signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave;

[0510] A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising:

[0511] An oscillator that generates:

[0512] Master clock signal,

[0513] a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and

[0514] a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase;

[0515] A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising:

[0516] a delay locked loop, the delay locked loop using the first phase clock signal and the second phase clock signal to generate a dual-frequency clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop is synchronized with the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer;

[0517] a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit;

[0518] a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit;

[0519] a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the ultrasonic transducer with the AC drive signal;

[0520] An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising:

[0521] at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal so that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency that is proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal;

[0522] a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem;

[0523] A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising:

[0524] a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and

[0525] A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the ultrasonic transducer to control the cavitation in the aqueous solution in response to a feedback signal indicative of the operation of the ultrasonic transducer.

[0526] 21. A system for generating hydrogen, the system comprising:

[0527] a reaction vessel containing an aqueous solution;

[0528] a first electrode positioned at least partially within the reaction vessel;

[0529] a second electrode positioned at least partially within the reaction vessel, wherein the first electrode and the second electrode are configured to receive power from a DC power source;

[0530] a first gas collector positioned at least partially within the reaction vessel for collecting hydrogen gas generated at the first electrode due to an electrolysis reaction at the first electrode;

[0531] an ultrasonic transducer located at a predetermined distance from the first electrode and oriented so that the ultrasonic transducer transmits ultrasonic waves at least partially toward the first electrode; and

[0532] A driver device electrically coupled to the ultrasonic transducer drives the ultrasonic transducer at a frequency to generate ultrasonic waves that induce cavitation in the electrolyte solution, wherein the cavitation increases the rate of the electrolysis reaction and increases the volume of hydrogen gas generated at the first electrode.

[0533] 22. A system for generating hydrogen, the system comprising:

[0534] a reaction vessel containing an aqueous solution;

[0535] a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode;

[0536] an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source;

[0537] a polymer electrolyte membrane (PEM) positioned between the cathode and the anode to separate the H+ ions and the OH- ions in the aqueous solution, thereby creating a partitioned region in the reaction vessel, wherein the aqueous solution in the partitioned region proximate the cathode has a higher concentration of H+ ions than OH- ions;

[0538] a first ultrasonic transducer at least partially positioned in the reaction vessel, the first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that the first ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode, thereby scavenging any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas; and

[0539] a second ultrasonic transducer, the second ultrasonic transducer being at least partially positioned in the reaction vessel, the second ultrasonic transducer being positioned at a predetermined distance from the anode and being oriented such that the second ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution, thereby separating individual water molecules that can be used to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen gas at the anode.

[0540] 23. A system for generating hydrogen, the system comprising:

[0541] a reaction vessel containing an aqueous solution;

[0542] a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode;

[0543] an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source;

[0544] at least one first ultrasonic transducer, the plurality of first ultrasonic transducers being at least partially positioned in the reaction vessel, each first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that each first ultrasonic transducer transmits and conducts ultrasonic waves through the aqueous solution at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode to thereby scavenge any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas; and

[0545] At least one second ultrasonic transducer, the at least one second ultrasonic transducer is at least partially positioned in the reaction vessel, each second ultrasonic transducer is positioned at a predetermined distance from the anode and is oriented so that each second ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution to separate single water molecules that can be used to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen at the anode.

Claims

1. A system for generating hydrogen, the system comprising: a reaction vessel containing an aqueous solution; a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode; an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source; a polymer electrolyte membrane (PEM) positioned between the cathode and the anode to separate the H+ ions and the OH- ions in the aqueous solution, thereby creating a partitioned region in the reaction vessel, wherein the aqueous solution in the partitioned region proximate the cathode has a higher concentration of H+ ions than OH- ions; a first ultrasonic transducer, the first ultrasonic transducer being at least partially positioned in the reaction vessel, the first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that the first ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode, thereby scavenging any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas; a second ultrasonic transducer, the second ultrasonic transducer being at least partially positioned in the reaction vessel, the second ultrasonic transducer being positioned at a predetermined distance from the anode and being oriented such that the second ultrasonic transducer transmits ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution to separate individual water molecules that can be used to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen gas at the anode; and a plurality of transducer drivers, each of which is electrically coupled to a corresponding one of the first ultrasonic transducer or the second ultrasonic transducer to drive the ultrasonic transducer to generate the ultrasonic wave, wherein the transducer driver comprises: An H-bridge circuit connected to the ultrasonic transducer, wherein the H-bridge circuit generates an AC driving signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave; A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising: An oscillator that generates: Master clock signal, a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase; A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising: a delay locked loop, the delay locked loop generating a dual-frequency clock signal using the first phase clock signal and the second phase clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop synchronizes the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer; a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit; a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit; a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the ultrasonic transducer with the AC drive signal; An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising: at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal such that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples an analog signal received at the ADC input terminal at a sampling frequency proportional to the frequency of the master clock signal, And the ADC subsystem generates an ADC digital signal using the sampled analog signal; a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem; A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising: a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the ultrasonic transducer to control the cavitation in the aqueous solution in response to a feedback signal indicative of the operation of the ultrasonic transducer.

2. A system for generating hydrogen, the system comprising: a reaction vessel containing an aqueous solution; a cathode positioned at least partially within the reaction vessel, wherein a portion of the cathode has an outer surface immersed in and in electrical contact with the aqueous solution to create an interface for a reduction reaction that reduces H+ ions to produce hydrogen gas at the cathode; an anode at least partially positioned within the reaction vessel, wherein a portion of the anode is immersed in and in electrical contact with the aqueous solution to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the cathode and the anode are configured to receive power from a power source; a plurality of first ultrasonic transducers, the plurality of first ultrasonic transducers being at least partially positioned in the reaction vessel, each first ultrasonic transducer being positioned at a predetermined distance from the cathode and being oriented such that each first ultrasonic transducer transmits and conducts ultrasonic waves through the aqueous solution at least partially toward the outer surface of the cathode to agitate the aqueous solution proximate the outer surface of the cathode to scavenge any bubbles of the hydrogen gas formed at the outer surface of the cathode to expose the outer surface of the cathode to additional H+ ions for generating hydrogen gas; a plurality of second ultrasonic transducers, the plurality of second ultrasonic transducers being at least partially positioned in the reaction vessel, the second ultrasonic transducers being positioned at a predetermined distance from the anode and being oriented such that the second ultrasonic transducers transmit ultrasonic waves at least partially toward the outer surface of the anode to induce cavitation in the aqueous solution near the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules of the aqueous solution to separate individual water molecules that can be used to interact with the anode to perform the oxidation reaction at the anode, thereby oxidizing OH- ions and forming oxygen gas at the anode; and a plurality of transducer drivers, each of the plurality of transducer drivers being electrically coupled to a corresponding one of the ultrasonic transducers to drive the ultrasonic transducer to generate the ultrasonic wave, wherein each transducer driver comprises: an H-bridge circuit connected to the corresponding one of the ultrasonic transducers, wherein the H-bridge circuit generates an AC drive signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave; A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising: An oscillator that generates: Master clock signal, a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase; A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising: a delay locked loop, the delay locked loop generating a dual-frequency clock signal using the first phase clock signal and the second phase clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop synchronizes the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer; a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit; a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit; a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the corresponding one of the ultrasonic transducers with the AC drive signal; An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising: at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal so that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal; a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem; A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising: a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the corresponding one of the ultrasonic transducers in response to a feedback signal indicative of the operation of the corresponding one of the ultrasonic transducers to control the cavitation in the aqueous solution.

3. The system according to claim 2, wherein the system comprises: A polymer electrolyte membrane (PEM) is positioned between the cathode and the anode within the reaction vessel to separate the H+ ions and the OH- ions in the aqueous solution, thereby creating a separation region in the reaction vessel, wherein the aqueous solution in the separation region proximate the cathode has a higher concentration of H+ ions than OH- ions.

4. The system of any one of the preceding claims, wherein the transducer driver drives the ultrasound transducer at a frequency of 20 kHz to 40 kHz.

5. The system of any one of the preceding claims, wherein each first ultrasonic transducer is positioned at a distance from the outer surface of the cathode corresponding to one wavelength of the ultrasonic wave emitted by the ultrasonic transducer.

6. The system of any one of claims 1 to 4, wherein each first ultrasonic transducer is positioned at a distance from the outer surface of the cathode that corresponds to a plurality of wavelengths of the ultrasonic waves emitted by the ultrasonic transducer.

7. The system of any one of the preceding claims, wherein each second ultrasonic transducer is positioned at a distance from the outer surface of the anode corresponding to one wavelength of the ultrasonic wave emitted by the ultrasonic transducer.

8. The system of any one of the preceding claims, wherein each second ultrasonic transducer is positioned at a distance from the outer surface of the anode corresponding to a plurality of wavelengths of the ultrasonic waves emitted by the ultrasonic transducer.

9. The system of any one of the preceding claims, wherein each first ultrasonic transducer is oriented to transmit ultrasonic waves in a direction transverse to the longitudinal extent of the cathode.

10. The system of any preceding claim, wherein each second ultrasonic transducer is oriented to transmit ultrasonic waves in a direction transverse to the longitudinal extent of the anode.

11. A system according to any one of the preceding claims, wherein the system comprises: A main controller controls power applied to the anode and the cathode, wherein the main controller is coupled to each transducer driver to control operation of each transducer driver to optimize efficiency of hydrogen generation.

12. The system of claim 11, wherein the system comprises: a hydrogen collector, the hydrogen collector being at least partially positioned in the reaction vessel and configured to collect hydrogen generated in the reaction vessel; and A hydrogen pressure sensor senses the hydrogen pressure in the hydrogen collector, and the hydrogen pressure sensor is electrically coupled to the main controller to provide a hydrogen pressure signal to the main controller in a feedback loop.

13. A system according to claim 11 or claim 12, wherein the system comprises: an oxygen collector, the oxygen collector being at least partially positioned in the reaction vessel and configured to collect oxygen generated in the reaction vessel; and An oxygen pressure sensor senses oxygen pressure within the oxygen collector, the oxygen pressure sensor being electrically coupled to the main controller to provide an oxygen pressure signal to the main controller in a feedback loop.

14. A system according to any one of the preceding claims, wherein the transducer driver comprises: A frequency divider is connected to the oscillator to receive the master clock signal from the oscillator, the frequency divider divides the master clock signal by a predetermined division amount and outputs a frequency reference signal to the delay locked loop.

15. The system of claim 14, wherein the delay locked loop comprises a plurality of delay lines connected end-to-end, wherein a total delay of the delay lines is equal to a period of the master clock signal.

16. The system of claim 15, wherein the delay locked loop adjusts the duty cycle of the first phase clock signal and the second phase clock signal in response to the driver control signal by changing the delay of each delay line in the delay locked loop.

17. A system according to any one of the preceding claims, wherein the feedback input terminal receives a feedback signal in the form of a voltage from the H-bridge circuit, the feedback signal being indicative of the rms current of the AC drive signal that is driving the ultrasonic transducer.

18. A system according to any of the preceding claims, wherein the ADC subsystem comprises at least one further ADC input terminal, the at least one further ADC input terminal receiving a feedback signal indicating at least one of a voltage of a battery connected to the system or a voltage of a battery charger connected to the system.

19. A system for generating hydrogen, the system comprising: a housing comprising a first interior chamber and a second interior chamber; an anode positioned at least partially within the first interior chamber, a portion of the anode being in electrical contact with water within the first interior chamber to create an interface for an oxidation reaction that oxidizes OH- ions to produce oxygen gas at the anode, wherein the anode is porous; a cathode positioned at least partially within the second interior chamber, wherein the cathode is porous, and wherein the cathode and the anode are configured to receive power from a power source; a polymer electrolyte membrane (PEM) positioned between the cathode and the anode, wherein the PEM allows H+ ions to cross from the anode to the cathode and the PEM prevents OH- ions from crossing from the anode to the cathode; an ultrasonic transducer positioned at least partially in the first interior chamber, the ultrasonic transducer positioned at a predetermined distance from the anode and oriented such that the ultrasonic transducer transmits ultrasonic waves at least partially toward a surface of the anode to induce cavitation in water proximate the outer surface of the anode, wherein the cavitation weakens hydrogen bonds between water molecules to separate individual water molecules available to interact with the anode to carry out the oxidation reaction at the anode to oxidize OH- ions and form oxygen gas at the anode; a transducer driver, the transducer driver being electrically coupled to the ultrasonic transducer to drive the ultrasonic transducer to generate the ultrasonic wave; and A hydrogen outlet allows hydrogen gas to be generated in the second interior chamber as the H+ ions are reduced at the cathode to generate the hydrogen gas.

20. The system of claim 19, wherein the system further comprises: A transducer driver coupled to the ultrasonic transducer, the transducer driver comprising: An H-bridge circuit connected to the ultrasonic transducer, wherein the H-bridge circuit generates an AC driving signal to drive the ultrasonic transducer to generate and transmit the ultrasonic wave; A microchip connected to the H-bridge circuit to control the H-bridge circuit to generate the AC drive signal, the microchip comprising: An oscillator that generates: Master clock signal, a first phase clock signal that is high at a first time during a positive half cycle of the master clock signal and is low during a negative half cycle of the master clock signal, and a second phase clock signal that is high at a second time during the negative half cycle of the master clock signal and is low during the positive half cycle of the master clock signal, wherein the first phase clock signal and the second phase clock signal are center aligned in phase; A pulse width modulation (PWM) signal generator subsystem, the PWM signal generator subsystem comprising: a delay locked loop, the delay locked loop generating a dual-frequency clock signal using the first phase clock signal and the second phase clock signal, the dual-frequency clock signal being twice the frequency of the master clock signal, wherein the delay locked loop synchronizes the first phase clock signal and the second phase clock signal, and wherein the delay locked loop adjusts the frequency and duty cycle of the first phase clock signal and the second phase clock signal in response to a driver control signal to generate a first phase output signal and a second phase output signal, wherein the first phase output signal and the second phase output signal are configured to drive the H-bridge circuit to generate the AC drive signal to drive the ultrasonic transducer; a first phase output signal terminal, the first phase output signal terminal outputting the first phase output signal to the H-bridge circuit; a second phase output signal terminal, the second phase output signal terminal outputting the second phase output signal to the H-bridge circuit; a feedback input terminal that receives a feedback signal from the H-bridge circuit, the feedback signal indicating a parameter of an operation of the H-bridge circuit or the AC drive signal when the H-bridge circuit is driving the ultrasonic transducer with the AC drive signal; An analog-to-digital converter (ADC) subsystem, the ADC subsystem comprising: at least one ADC input terminal that receives an analog signal, wherein the ADC input terminal is connected to the feedback input terminal so that the ADC subsystem receives the feedback signal from the H-bridge circuit, and wherein the ADC subsystem samples the analog signal received at the ADC input terminal at a sampling frequency that is proportional to the frequency of the master clock signal, and the ADC subsystem generates an ADC digital signal using the sampled analog signal; a digital processor subsystem that receives the ADC digital signal from the ADC subsystem and processes the ADC digital signal to generate the driver control signal, wherein the digital processor subsystem transmits the driver control signal to the PWM signal generator subsystem to control the PWM signal generator subsystem; A digital-to-analog converter (DAC) subsystem, the DAC subsystem comprising: a digital-to-analog converter (DAC) that converts a digital control signal generated by the digital processor subsystem into an analog voltage control signal to control a voltage regulator circuit that generates a voltage for modulation by the H-bridge circuit; and A DAC output terminal is provided to output the analog voltage control signal to control the voltage regulator circuit to generate a predetermined voltage for modulation by the H-bridge circuit, thereby driving the ultrasonic transducer to control the cavitation in the aqueous solution in response to a feedback signal indicative of the operation of the ultrasonic transducer.

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