Systems and Methods for Controlling Current During Electrochemical Processes

Description

BACKGROUND OF THE INVENTION

Field of the Invention

This disclosure is related to the field of electrochemical processing, and more particularly to a method and system for controlling and modulating current during electrochemical processes, such as, but not limited to, anodizing aluminum and electroplating.

Description of the Related Art

Electrochemical processing is a process that involves utilizing electrical energy to induce chemical reactions and was first developed in the 18^th century. Over the centuries following its discovery, electrochemical processing has been improved upon and is currently used in a wide variety of manufacturing processes to change the physical properties of materials and objects. For instance, electroplating—a form of electrochemical processing—can be used to increase wear resistance, corrosion protection, or even the aesthetic appeal of various materials.

At a high level, electroplating requires a cathode and anode, which are placed in an electrolytic solution, and a power supply that supplies an electric charge to the cathode and anode. As the current is supplied, the metal oxidizes and metal atoms are dissolved into the solution. The negative ions in the solution are drawn to the anode and the positive ions in the solution are drawn to the cathode (or substrate), covering the desired part in a thin layer of metal.

Multiple factors can impact the effectiveness of the electroplating process. Some of these factors include: the temperature of the electrolytic solution; the chemical composition of the solution; the distance between the anode and cathode in the solution; where the anode and cathode are placed in the solution (i.e., the depth at which the anode and the cathode are placed in the solution); the length of time the electrical current is applied to the anode; the voltage of the power supply; and the current of the power supply. Altering any one factor can impact the effectiveness of the electroplating process, but altering the voltage and current of the power level, particularly, can drastically impact the efficacy of the process.

As electrochemical processes have continued to be improved over the years, various methods to increase the effectiveness and efficacy of the process have been developed. For example, U.S. Pat. No. 4,128,461 issued to Lerner et al in 1978 (the '461 patent), the entire disclosure of which is hereby incorporated by reference, describes a process of using an electrolyte solution with sulfuric acid and an organic extract known as Sanfran added thereto and then applying an AC modulated DC voltage to produce a hard oxide coating on the material being processed. The AC voltage modulating the DC voltage in the process described in the '461 patent is the sinusoidally alternating 60 Hz electrical power that is generally available from electrical mains in the United States. The '461 patent describes the DC voltage as being the carrier voltage, while the AC voltage is the modulating voltage, and further describes the process as maintaining the solution temperature constant and gradually increasing the DC voltage from 0 to 10 volts up to 50 or more volts throughout the anodizing process. The process of the '461 patent purportedly improves the electrochemical process of anodizing by reducing the amount of sulfuric acid required, allowed higher temperatures of the electrolyte solution, and producing a thicker anodized coating on the material processed.

Similarly, other methods for creating a relatively thick, hard, wear-and-corrosion-resistant layer of an oxide film on the surface of the material being processed have also been developed. For instance, it has been known in the art since at least 1978 that maintaining the electrolyte solution of strong acids, such as sulfuric acid, chromic acid, oxalic acid, etc., at a low temperature and applying high voltage yields a thick, hard coating on the material subjected to the electrochemical process. Such a process is described in U.S. Pat. No. 4,089,756 to Lerner et al (the '756 patent), the entire disclosure of which is hereby incorporated by reference. The '756 patent describes using a wide variety of voltages (up to 70 volts DC or more) and an electrolyte solution, which is maintained at a low temperature via a cooling system, to facilitate either continuous anodizing or batch anodizing. Because different materials may need to be processed for different lengths of time, and because the operating conditions described in the '756 patent would generally present significant shock hazards for the personnel operating the system, the '756 patent uses a grounded conveyor to eliminate the risk of shock to personnel touching the conveyor or removing materials on the conveyor, which also allows different materials to be processed for different lengths of time without turning off the operating voltage.

Other methods have also attempted to be developed to increase the thickness of the oxide layer deposited during electrochemical processes and still others have been attempted to improve the overall efficiency of the electrochemical process. Some of these other methods describe various techniques that attempt to improve various aspects of the electrochemical process, including attempts at varying the amount of time the voltage is applied, using unbalanced AC voltage for supplying DC with superimposed AC, controlling and manipulating the voltage applied in the electrochemical process, and changing the electrical frequency used in the electrochemical process by manipulating the voltage. Though, as described herein, these other methods are imperfect solutions to improving electrochemical processes.

For instance, one scholarly article, AC-Bipolar Anodization of Aluminum: Effects of Frequency on Thickness of Porous Alumina Films, by Hidetaka Asoh, Mami Ishino, and Hideki Hashimoto, published in the Journal of The Electrochemical Society in 2018, the entirety of which is hereby incorporated by reference, discusses how changing the frequency applied can impact the film formation (both the pore diameter and the thickness of the film) in the electrochemical process. The Asoh et al article describes experiments using 60V and 5V during the anodization process and explains that using frequencies in the range of 50 to 150 Hz are efficient for film formation. Interestingly, while Ohm's law dictates that voltage is the product of current times resistance (V=IR) and this formula generally indicates that voltage and current are directly related to one another, the Asoh et al article notes that this is not necessarily true when it comes to electrochemical processes. This is likely because resistance increases as an aluminum article is anodized, which necessarily results in current decreasing while voltage is held constant (i.e., because voltage is the product of current and resistance, when resistance increases, current must decrease to yield the same voltage). Additionally, the article explains that even though the relationship between voltage and frequency is well-known, the relationship between current and frequency is not presently understood and requires further investigation.

Other scholarly articles similarly discuss how increasing the AC voltage in a DC and AC electrochemical process can improve the formed oxide layer, particularly when the frequency is about 60 Hz, and how the resistance of the aluminum specimen being processed changes due to the presence of excess free oxygen that is produced during anodization. This generation of free oxygen requires an overvoltage of about 6 volts to be applied to facilitate the breakdown of the free oxygen. Interestingly, no scholarly articles discuss increasing the current applied, or even how changing the current can impact the anodization process. This is likely because, as explained in the Asoh et al article, frequency is directly related to the pore size and thickness of the oxide film and the relationship between current and frequency during electrochemical processes is not presently understood.

Additionally, the methods that have been attempted to improve electrochemical processes, like anodization, which generally all focus on the same factors—controlling or modifying the voltage, or modifying the electrolyte solution or duration the specimen is processed—are imperfect because the main focus of these methods is on controlling DC voltage that is modulated with AC voltage, resulting in a following and tracking function of DC and AC current. But because of this, these methods are generally restricted to the functional AC modulation frequencies of 50 and 60 Hz, as provided by the local industrial or municipal power supply distribution network.

Additionally, because voltage is a measure of potential electrical energy and not actual electric charge, controlling voltage is not a precise means of controlling the electric energy applied to the electrochemical process. Voltage control of a power supply produces a specific voltage output into a variety of load resistance conditions, including a short circuit producing a resultant current. This generally provides a low output impedance of the power supply. It is known that low output impedance reduces noise, maintains constant voltage when current fluctuates, and generally has a minimal voltage drop under varying load conditions. These reasons make low output impedance desirable in most power supplies, but not in power supplies for electrochemical processes.

In electrochemical processes, the material being processed is the load and different materials have different characteristics. With voltage control of a power supply, the low output impedance means the voltage will be mostly constant, despite current fluctuations and varying loads, which can produce unpredictable results or cause major problems in the system. This is particularly true when anodizing an aluminum article because, as explained above, the resistance increases as aluminum materials are subjected to electrochemical processing, so maintaining a constant voltage results in the current decreasing. This can result in the power supply failing, exhibiting erratic oscillations, becoming unstable, or being damaged when the current decreases low enough that the power supply can no longer meet the demands of the system.

Moreso, output impedance of a power supply increases with frequency, and, as described above, frequency has a direct relation to the formation of oxide films in the electrochemical process. However, a power supply with a low output impedance can fail due to too high a frequency, which may result in a limited range of frequencies tolerable before the power supply fails. This limitation that comes with voltage control of a power supply may hinder the development of improved oxide films by restricting the possibilities of available frequencies.

SUMMARY OF THE INVENTION

The following is a summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The sole purpose of this section is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

With current control of a power supply, the power supply produces a specific current output into a variety of load resistance conditions, including a short circuit producing a resultant voltage, and provides a very high output impedance of the power supply. The high output impedance of a power supply is beneficial where maintaining a constant current is important, even with changes in the load resistance. Moreso, current control of a power supply permits adjusting the frequency through a wide range that can ensure the system is tuned to the proper harmonic to prevent out of phase current and voltage conditions that could result in failure of the power supply. In electrochemical processing applications, this means the frequency can be adjusted for resonance with relation to the physical load of the material being processed, which improves the power factor without losses that would be seen in with voltage control of a power supply. Additionally, because electrical work is calculated as the product of current times voltage, current control of a power supply during anodizing aluminum can result in more work done in a shorter period of time because current does not decrease with an increase in resistance. This is unlike voltage control of a power supply that, as described above, maintains voltage constant with current decreasing as resistance is increased.

Because of the above, and other problems in the art, described herein, among other things, is an improved system and method of using current control of a power supply in electrochemical processing, such as but not limited to anodizing aluminum and aluminum alloys and general electroplating. More specifically, the system and method of the present disclosure produces controlled DC current that is AC modulated at selectable frequencies, and which produces a following and tracking DC and AC voltage. As described further herein, the control of current, which is a measure of the actual electric charge that is delivered, rather than the control of voltage, which is a measure of the potential electrical energy, is a significant improvement over the previously existing systems and methods that allows for more a efficient and predictable electrochemical process that is less prone to failure.

There are described herein, systems and methods for controlling current during electrochemical processes, such as electroplating, anodizing, and others. The disclosed systems and methods utilize a microcontroller system that receives inputs from various current and voltages sensors and monitors the various current and voltage readings throughout the system. The microcontroller system further compares the measured system current to a target system operating current, which the microcontroller may have established based on a user inputting desired features, values, and parameters of the system, and the microcontroller identifies deviations between the measured current and target system operating current. The microcontroller system may then adjust the bias of semiconductor arrays to modulate the measured current to maintain the modulated current generally at said target system operating current and maintain a modulation frequency on said modulated current, may shut the system down if the measured current exceeds a certain predetermined safe operating threshold, and may send alerts to a user to notify the user of various information regarding the system, such as when a safe operating parameter is exceeded or when another threshold is met or exceeded.

In an embodiment, there is a system for controlling current during electrochemical processes, the system comprising an electrochemical cell with a tank with an electrolyte solution, an anode and a cathode, and a power supply, a current sensor, one or more semiconductor arrays, a microcontroller system, and a target system operating current, wherein the microcontroller system modulates the system's measured current to maintain the modulated current generally at the target operating current by adjusting the semiconductor bias.

In an embodiment, the system's target operating current is established based on user inputs that may include any of the following or any combination of the following: the type of alloy of the article being processed, the surface area of the article being processed, the characteristics of the electrolyte solution, and the desired thickness of the anodic layer.

In an embodiment, the system further includes a plurality of sensors, including at least one current sensor suitable to measure AC current, at least one current sensor suitable to measure DC current, at least one voltage sensor suitable to measure AC voltage, and at least one voltage sensor suitable to measure DC voltage.

In another embodiment, the microcontroller of the disclosed system sets a safe operating system current and voltage threshold, which may be established based on a user inputting desired features, values, and parameters, and the microcontroller system monitors current and voltage from the plurality of sensors and shuts the system down and sends an alert when the measure parameters exceed the safe operating thresholds.

In an embodiment, the microcontroller system may further include a display screen that displays the monitored parameters and alerts.

In another embodiment, the microcontroller system may be in communication with a computer network that is connected to the internet and the microcontroller system may send various alerts via email or internet based messaging, such as a text message sent via the internet.

Also as described herein is a method for controlling current during electrochemical processes, the method comprising, providing a system for controlling current during electrochemical processes, including an electrochemical cell with a tank with an electrolyte solution, an anode and cathode, a power supply, a current sensor for measuring the current in the system, one or more semiconductor arrays, with the microcontroller system setting a target system operating current and comparing the measured current to the target system operating current, and the microcontroller system identifying deviations between the measured current and the target system operating current and adjusting the bias of the semiconductor arrays to modulate the measured current to maintain the modulated current generally at said target system operating current, and adjusting the frequency of the system for resonance with said system for resonance with relation to said cell.

In another embodiment, the method's system's target operating current is established based on user inputs that may include any of the following or any combination of the following: the type of alloy of the article being processed, the surface area of the article being processed, the characteristics of the electrolyte solution, and the desired thickness of the anodic layer.

In an embodiment, the method further includes a plurality of sensors, including at least one current sensor suitable to measure AC current, at least one current sensor suitable to measure DC current, at least one voltage sensor suitable to measure AC voltage, and at least one voltage sensor suitable to measure DC voltage.

In another embodiment, there is described herein a method of AC electrolytic anodizing, the method comprising providing a system for controlling current during electrochemical processes, including an electrochemical cell with a tank including an electrolyte solution, an anode and cathode, and a power supply, a current sensor for measuring current in the system, a microcontroller system, a positive DC voltage rail, a negative DC voltage rail, at least one means of controlling said positive DC voltage rail and said negative DC voltage rail, one or more semiconductor arrays on the positive DC voltage rail, one or more semiconductor arrays on the negative DC voltage rail, with the means of controlling the positive and negative DC rails generating a positive half of a waveform on the positive DC voltage rail and a negative half of the waveform on said negative DC voltage rail, and with the positive half of the waveform being combined with the negative half of the waveform to create a synthesized AC waveform, and also with the microcontroller system setting a target system operating current and comparing the measure current to the target operating current and identifying a deviation between the measured current and the target operating current and adjusting the bias of the semiconductor arrays on the positive DC voltage rail and semiconductor arrays on the negative DC voltage rail to modulate the measured current to maintain the modulated current generally at the system operating current, and the microcontroller system electrically communicating with the semiconductor arrays on the positive DC voltage rail and the semiconductor arrays on the negative DC voltage rail to control the frequency of the synthesized AC waveform.

There is also described herein, a method of continuous coil anodizing, the method including providing a system for controlling current during electrochemical processes, including an electrochemical cell with a tank including a electrolyte solution, a coil, a plurality of cathodes, wherein the plurality of cathodes includes cathodes of varying resistive values, and a power supply, and a current sensor for measuring the current in the system, a voltage sensor for measuring the voltage in the system, one or more semiconductor arrays, and a microcontroller system. The method further including placing each cathode of the plurality of cathodes in order of decreasing resistive value in the electrolyte solution, submerging the coil in the electrolyte solution at the location of the highest resistive value cathode, applying a steady voltage to the system, with the microcontroller system monitoring the measured voltage and adjusting the bias of the semiconductor arrays to maintain the system at a steady voltage, and simulating a ramp profile of slowly increasing current by moving the coil past each cathode and through the electrolyte solution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an electrical circuit of an embodiment of systems and methods of controlling current during electrochemical processes.

FIG. 2 depicts an electrical circuit of an embodiment of systems and methods of controlling current during AC electrolytic anodizing.

FIG. 3 schematically depicts an arrangement of an embodiment of systems and methods of controlling current during continuous coil anodizing.

FIG. 4 depicts a illustration of an electroplating process using a tank, an electrolyte solution, an anode, a cathode, and a power supply.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure provides systems and methods for controlling current during electrochemical processes, which improves the efficiency, efficacy, and predictability of the process and allows more electric work to be done in a shorter period of time. At a high level, the invention described herein utilizes well-known components of an electroplating process, such as an electrochemical cell, including, as depicted in FIG. 4, a tank (401), an electrolyte solution (403), an anode (119), a cathode (117), and a power supply (405), and a microcontroller system (111). Although, as described further herein, the systems and methods of the present disclosure utilize these components, along with other elements that are not well-known components of electroplating processes, in a novel and unique manner according to the disclosed methods.

The tank (401) of the disclosed systems may be made of any non-conductive material that is safe to contain the electrolyte solution and chemicals therein. For instance, in one embodiment, the tank (401) is made of a urethane plastic material. In other embodiments, the tank (401) is made of polypropylene. In still further embodiments, the tank (401) could be made from polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), a polycarbonate resin thermoplastic, such as Lexan, or other similar materials. However, these examples of tank (401) materials are illustrative only and other materials that are suitable to contain the electrolyte solution chemicals and the other components of the system may be used as the tank material. In some embodiments, the tank (401) is manufactured by 3D printing methods that are generally known in the art to a person of ordinary skill. In other embodiments, the tank (401) is manufactured by traditional manufacturing processes.

The electrolyte solution (403) of the present disclosure generally is comprised of any electrically conductive chemical solution with sufficient oxygen concentration that is known in the art to be suitable for anodization processes. For instance, in some embodiments, the electrolyte solution (403) may be comprised of sulfuric acid, sodium sulfate, acetic acid, phosphoric acid, hydrofluoric acid, or any combination thereof. In other embodiments, the electrolyte solution (403) may comprise a dimethyl sulfone, aluminum halide, ammonium chloride, or tetraalkylammonium chloride, or any combination thereof. In further embodiments, the electrolyte solution (403) may be comprised of a solution similar to the solution disclosed in U.S. Pat. No. 9,068,270 to Hoshi et al, the entire disclosure of which is hereby incorporated by reference. Additionally, in some embodiments, the electrolyte solution (403) may also contain an organic additive, such as Sanfran®, which is described in U.S. Pat. No. 2,743,221 to Sanford, the entire disclosure of which is hereby incorporated by reference, or other organic additives as desired by the user for particular applications.

The anode (119) and cathode (117) of the disclosed system generally are two electrodes that are immersed in the electrolyte solution (403) and electrically connected to the power source (405), with the anode (119) being the part used for plating and the cathode (117) being the part that will be plated, as is typical in electroplating processes known by persons of ordinary skill in the art. Like the electrolyte solution (403) and tank (401), the particular anode (119) and cathode (117) used in the disclosed system may vary based on the circumstances and particular application in which the system is used. For instance, in an embodiment specific to anodizing aluminum, an aluminum part may be used as the anode (119) and in other embodiments, the anode (119) may be materials other than aluminum, such as gold, silver, copper, nickel, cadmium, or other similar metals. In some embodiments, the cathode (117) may be an aluminum alloy, stainless steel, carbon steel, high strength steel, copper alloy, iron alloy, nickel alloy, cobalt alloy, or any combination thereof may be used as the cathode (117). Additional materials may also be used at the cathode (117) in embodiments centered on aluminum anodization, provided the material is suitable for use in the system.

The power supply (405) of the disclosed systems may be any type of power supply that is typically used in the art of electrochemical processes. In some embodiments, the power supply (405) is a standard three phase industrial service feed. In other embodiments, the power supply (405) in a 220 volt supply. In further embodiments, the power supply may be any other power source (405) that can be integrated into the system. In any case, it is desirable for the power supply (405) used in the system to be operated in current control mode, as described further herein.

The microcontroller system (111) of the disclosed systems and method for controlling current during electrochemical processes is the control system of the disclosed systems and generally comprises a computer, a network, software, a server, a processor, and input from a plurality of sensors. The plurality of sensors, described further herein, include current sensors that are suitable to measure AC current, current sensors that are suitable to measure DC current, voltage sensors that are suitable to measure AC voltage, and voltage sensors that are suitable to measure DC voltage.

It should be noted that throughout this disclosure, the term “computer” describes hardware that generally implements functionality provided by digital computing technology, particularly computing functionality associated with microprocessors. The term “computer” is not intended to be limited to any specific type of computing device, but it is intended to be inclusive of all computational devices including, but not limited to: processing devices, microprocessors, personal computers, desktop computers, laptop computers, workstations, terminals, servers, clients, portable computers, handheld computers, smart phones, tablet computers, mobile devices, server farms, hardware appliances, minicomputers, mainframe computers, video game consoles, handheld video game products, and wearable computing devices including, but not limited to eyewear, wrist wear, pendants, and clip-on devices.

As used herein, a “computer” is necessarily an abstraction of the functionality provided by a single computer device outfitted with the hardware and accessories typical of computers in a particular role. By way of example and not limitation, the term “computer” in reference to a laptop computer would be understood by one of ordinary skill in the art to include the functionality provided by pointer-based input devices, such as a mouse or track pad, whereas the term “computer” used in reference to an enterprise-class server would be understood by one of ordinary skill in the art to include the functionality provided by redundant systems, such as RAID drives and dual power supplies.

It is also well known to those of ordinary skill in the art that the functionality of a single computer may be distributed across a number of individual machines. This distribution may be functional, as where specific machines perform specific tasks; or, balanced, as where each machine is capable of performing most or all functions of any other machine and is assigned tasks based on its available resources at a point in time. Thus, the term “computer” as used herein, may refer to a single, standalone, self-contained device or to a plurality of machines working together or independently, including without limitation: a network server farm, “cloud” computing system, software-as-a-service, or other distributed or collaborative computer networks.

Those of ordinary skill in the art also appreciate that some devices that are not conventionally thought of as “computers” nevertheless exhibit the characteristics of a “computer” in certain contexts. Where such a device is performing the functions of a “computer” as described herein, the term “computer” includes such devices to that extent. Devices of this type include but are not limited to: network hardware, print servers, file servers, NAS and SAN, load balancers, and any other hardware capable of interacting with the systems and methods described herein in the matter of a conventional “computer.”

For purposes of this disclosure, there will also be significant discussion of a special type of computer referred to as a “mobile communication device”. A mobile communication device may be, but is not limited to, a smart phone, tablet PC, e-reader, satellite navigation system (“SatNav”), fitness device (e.g., a Fitbit™ or Jawbone™) or any other type of mobile computer whether of general or specific purpose functionality. Generally speaking, a mobile communication device is network-enabled and communicating with a server system providing services over a telecommunication or other infrastructure network. A mobile communication device is essentially a mobile computer, but one which is commonly not associated with any particular location, is also commonly carried on a person, and usually is in constant communication with a network.

Throughout this disclosure, the term “software” refers to code objects, program logic, command structures, data structures and definitions, source code, executable and/or binary files, machine code, object code, compiled libraries, implementations, algorithms, libraries, or any instruction or set of instructions capable of being executed by a computer processor, or capable of being converted into a form capable of being executed by a computer processor, including without limitation virtual processors, or by the use of run-time environments, virtual machines, and/or interpreters. Those of ordinary skill in the art recognize that may be wired or embedded into hardware, including without limitation onto a microchip, and still be considered “software” within the meaning of this disclosure. For purposes of this disclosure, software includes without limitation: instructions stored or storable in RAM, ROM, flash memory BIOS, CMOS, mother and daughter board circuitry, hardware controllers, USB controllers or hosts, peripheral devices and controllers, video cards, audio controllers, network cards, Bluetooth® and other wireless communication devices, virtual memory, storage devices and associated controllers, firmware, and device drivers. The systems and methods described here are contemplated to use computers and computer software typically stored in a computer-or machine-readable storage medium or memory.

Throughout this disclosure, terms used herein to describe or reference media holding software, including without limitation terms such as “media,” “storage media,” and “memory,” may include or exclude transitory media such as signals and carrier waves.

Throughout this disclosure, the term “network” generally refers to a voice, data, or other telecommunications or similar network over which computers communicate with each other. The term “server” generally refers to a computer providing a service over a network, and a “client” generally refers to a computer accessing or using a service provided by a server over a network. Those having ordinary skill in the art will appreciate that the terms “server” and “client” may refer to hardware, software, and/or a combination of hardware and software, depending on context. Those having ordinary skill in the art will further appreciate that the terms “server” and “client” may refer to endpoints of a network communication or network connection, including but not necessarily limited to a network socket connection. Those having ordinary skill in the art will further appreciate that a “server” may comprise a plurality of software and/or hardware servers delivering a service or set of services. Those having ordinary skill in the art will further appreciate that the term “host” may, in noun form, refer to an endpoint of a network communication or network (e.g., “a remote host”), or may, in verb form, refer to a server providing a service over a network (“hosts a website”), or an access point for a service over a network. Servers and clients may also exist virtually in so-called “cloud” arrangements.

Throughout this disclosure, the term “real-time” generally refers to software performance and/or response time within operational deadlines that are effectively generally cotemporaneous with a reference event in the ordinary user perception of the passage of time for a particular operational context. Those of ordinary skill in the art understand that “real-time” does not necessarily mean a system performs or responds immediately or instantaneously. For example, those having ordinary skill in the art understand that, where the operational context is a graphical user interface, “real-time” normally implies a response time of about one second of actual time for at least some manner of response from the system, with milliseconds or microseconds being preferable. However, those having ordinary skill in the art also understand that, under other operational contexts, a system operating in “real-time” may exhibit delays longer than one second, such as where network operations are involved which may include multiple devices and/or additional processing on a particular device or between devices, or multiple point-to-point round-trips for data exchange among devices.

Those of ordinary skill in the art will further understand the distinction between “real-time” performance by a computer system as compared to “real-time” performance by a human or plurality of humans. Performance of certain methods or functions in real-time may be impossible for a human, but possible for a computer. Even where a human or plurality of humans could eventually produce the same or similar output as a computerized system, the amount of time required would render the output worthless or irrelevant because the time required is longer than how long a consumer of the output would wait for the output, or because the number and/or complexity of the calculations, the commercial value of the output would be exceeded by the cost of producing it.

Electrochemical processes are generally carried out as follows: preparing, in the tank, an electrolyte solution that is suitable for the desired electrochemical process, preparing the article to be processed in accordance with typical methods known in the art of electrochemical processing, electrically connecting the positive terminal of the power supply (123) to the anode (119), electrically connecting the negative terminal of the power supply (123) to the cathode (117), heating the electrolyte solution to the desired temperature, submerging the anode (119) and cathode (117) in the electrolyte solution, processing the article for a predetermined period of time, and then removing the article from the electrolyte solution. At the most rudimentary level, the disclosed method improves on this general method of electrochemical processing by improving the electrical control of the process and, as depicted in FIG. 1, utilizing semiconductor arrays (115) in a fully analog or synthesized digital to analog method of generation, monitoring the current in the system, and utilizing a microcontroller system (111) to control a rectifier, modulate the current, and log and report system operation.

In the embodiment depicted in FIG. 1, power enters the system, goes through a rectification section, a surge and sag filter array, a noise snubbing filter array, and continues to flow through the circuit, including through the semiconductor arrays (115), to the electrochemical cell (121). It should be noted that, as described above, the power source (123) could be a 3-phase industrial service feed, 3-phase or single phase at 50 Hz, 60 Hz, or other standard frequency, or could be a 220 volt source, or another power source (123) that can be integrated into the system. It should be further noted that in some embodiments, the power input to the system could be direct and in other embodiments, the power input could be through step down or step up transformers.

The rectification section (125) in the embodiment depicted in FIG. 1 includes a phase controlled firing board, which is generally known in the art to those of ordinary skill. The phase controlled firing board (131) may control its semiconductor devices in a phase controlled or switch mode rectification operation. The rectification section (125) further may include a 6 pulse thyristor bridge, a thyristor 3 phase rectifier bridge, or a switch mode 3 phase rectifier bridge. This rectification section (125) generally produces a desired DC output voltage through a method of power generation, such as through a diode network, through phase controlled firing of silicon controlled rectifiers (SCR rectifiers), through switch mode silicon devices, through a 12 pulse or 24 pulse, or through similar phase controlled mechanisms and/or switch mode power supplies, which may allow the system to operate in very high power operations. Throughout this disclosure, the output of the rectification section (125) may be referred to as the “+DC Rail.”

The surge and sag filter array (127) of the embodiment depicted in FIG. 1 filters the power going through the system and stores excess energy in various capacitors. As current draw increases during the high side operation of the AC modulated DC current of the power semiconductor output section (113), as described further herein, the energy stored in capacitors of the surge and sag filter array (127) is drawn upon to meet the current demands of the system. This is an improvement to the alternative method of raising the +DC Rail voltage to supply the increased current needed during high side modulation. When the energy stored in the capacitors is discharged and as the current demands of the system decrease, the rectifier section (125) replenishes the capacitors supply of excess energy, which can then be used again when the current demands of the system increase.

To assist in reducing noise and distortion, which is common in essentially all electrical circuits, the noise snubbing filter array (129) of the embodiment depicted in FIG. 1 may filter high frequency switching noise and distortion from the +DC Rail. The noise snubbing filter array (129) comprises one or more resistors and one or more capacitors, networked in series, and tuned to the frequency of the rectifier switching. This may allow those specific frequency pulses to pass from the +DC Rail to ground as a controlled short, which in turn, may dissipate distortion and prevent noise or distortion from being present on the controlled high precision output. In some embodiments, the noise snubbing filter arrays (129) may be arranged in parallel, which may increase the snubbing filter arrays reduction, in both the magnitude and wattage, of distortion and or noise.

As described above, the system includes a plurality of sensors, which may be integrated throughout the system to measure the system AC, DC current, AC voltage, and DC voltage. As seen in the embodiment depicted in FIG. 1, a DC voltage sensor (101) may be positioned in the circuit after the noise snubbing filter array (129). This voltage sensor (101) may be referred to as the “Rail Voltage Monitoring” sensor and may continually measure the system's static and varying outputs and the system's response thereto. Generally, DC voltage is desired to be maintained and controlled from the output of the input rectifier section (125) so that the output sections can be modulated for desired functions. This voltage sensor (101) may feed into the microcontroller system (111) to provide information regarding the system's static and varying outputs, which may be used for control of the system.

Similarly, a DC current sensor (103) is positioned inline with the +DC Rail, generally between the noise snubbing filter array (129) and the power semiconductor output section (113), as described further herein. This DC current sensor (103) may measure the nominal DC current that is generated while the output devices are being driven. As this DC current is measured, desired AC signals may be applied to the output semiconductor sections (113) to produce the desired AC modulation to the total current output. This DC current sensor (103) feeds into the microcontroller system (111), providing information related to nominal DC current generated, which may be used within the microcontroller system (111) for controlling the system or comparing various currents measured throughout the system.

An additional DC voltage sensor (105) and an AC voltage sensor (107) are positioned in the system to measure the voltage, both AC voltage and DC voltage, applied to the electrochemical cell (121) being driven by the system, for example between the anode (119) and cathode (117), as depicted in FIG. 1. These voltage sensors (105) and (107) may measure both the applied voltage and induced voltage stimuli. The voltage sensors (105) and (107) may further provide input to the microcontroller system (111), including feedback on the applied and induced voltage stimuli, which may be used within the microcontroller system (111) for control, safety features, record keeping, or control of the system.

An additional DC current sensor (109) and an AC current sensor (110) are positioned in the system on the power return line of the output cell (121) and may measure the current applied to the electrochemical cell (121) being driven by the system. These current sensors (109) and (110), like voltage sensors (109) and (110), may also provide input to the microcontroller system (111), including feedback on the current applied to the cell (121), which may be used within the microcontroller system (111) for comparing current generated to current applied to the cell (121), for safety features, record keeping, or control of the system.

The power output section (113) of the system is positioned prior to the electrochemical cell (121) being driven by the system, and may utilize individual or parallel configured high power semiconductor devices (115) to regulate and control the power delivered to the cell (121) during operation of the system. In embodiments utilizing parallel configured high power semiconductor devices (115), the devices are desirably balanced by utilizing resistors on both the power input devices and the drive signals to the devices, such that the devices share the full amount of power safely. In addition to ensure safe operation, this configuration may further serve to assist in failure identification and prevention.

The semiconductor devices (115) utilized in the power output section (113) are a significant improvement over prior systems and methods of electrochemical processes for multiple reasons. Most notably, the use of a digital or analog drive control of power output semiconductor transistors (115) in the disclosed system allows the current control method of operation, as opposed to the traditional voltage control method, because the transistor amplifies a small current entering the base to produce a large collector current (i.e., the device is current-driven since the collector current is controlled via the base current) and the current gain varies with the collector-emitter voltage. Also, utilizing these devices (115) allows the electrochemical bath to be tuned for resonance with relation to the physical load that is submerged within and being processed.

Additionally, the disclosed system utilizing these semiconductor devices (115) allows the control of amplitude and frequency modulation that is overlaid on the DC carrier current, and the production of a wide range of frequencies for the AC modulation that is overlaid on the DC carrier current, without being limited to industrial frequences of 50 Hz or 60 Hz and allowing high voltages of up to or exceeding 70 volts. Further, the use of these semiconductor devices (115) allows the system to deliver precise and repeatable energy to the load being processed, which results in consistent production and precise process control based on known input variables of current, frequency, modulation percentage, and total energy delivered. Moreso, the semiconductor devices (115) used in the disclosed system allow the ability of constant, real time, or near real time, data monitoring of the measured process feedback to maintain process parameters and ensure proper system operation, including detecting and responding to process issues such as load condition fluctuations.

Thus, the disclosed system's use of semiconductor devices (115) in the power output section (113) allows the frequency of the system to be adjusted for resonance, which allows the circuit to be tuned to the proper harmonic to minimize out of phase current and voltage conditions that are commonly seen in inductive or capacitive load circuits, such as used in exiting electrochemical processes. As is known in the art, proper harmonic configuration produces a higher amount of actual energy delivered to the physical load because current and voltage are in phase as opposed to out of phase, which results in a more efficient energy delivery (measured as power factor) without the commonly seen losses.

Additionally, semiconductor devices are not commonly known in the art to be used in large arrays such as how the semiconductor devices (115) are used in the disclosed system because there are few applications that require the capabilities of a large array. As such, large arrays of semiconductor devices was typically limited to amplification of musical instruments to drive magnetic coils in speakers, auditory or sensory area denial apparats, or, uncommonly, for battery testing and formation. But these devices were not generally used in electrochemical processes. However, contrary to this general practice, the disclosed systems and methods utilize such large arrays of semiconductor devices (115) in the power output section (113), which allows the system to operate up to extremely high, yet precisely delivered output power levels (i.e., current density), with the frequency fine tuned to the resonance of the physical load being processed, which makes the disclosed system and method a more efficient and improved method of electrochemical processing.

In addition to the microcontroller system (111) using inputs from any or all of the voltage and current sensors, (101), (103), (105), (107), (109), and (110), as described above, the microcontroller system (111) may also control or maintain the bias of the semiconductor devices (115) in the power output section (113) to control and maintain the desired output characteristics of the system, may monitor various aspects of the system, and may further provide various alerts when a system parameter exceeds threshold levels. Specifically, the microcontroller system (111) may monitor system voltage and current, based on input from the various current and voltage sensors (101), (103), (105), (107), (109), (110), monitor the system current and voltage output, including monitoring the system outputs to detect deviations in expected functions that may indicate component failure or unsafe operating condition, display the system current and voltage levels, and provide alerts when a monitored parameter may be exceeding a predetermined safe operating level.

Further, the microcontroller system (111) may compare the measured current and voltage values to a set of target system operating parameters and adjust the semiconductor (115) bias as needed to maintain the desired parameters in the system. The target system operating parameters and the safe operating thresholds may be established by the microcontroller system (111) based on a user inputting desired features or values or parameters, such as the alloy of the article being processed, the surface area of the article, the characteristics of the electrolyte solution, the desired thickness of the anodic layer, into the microcontroller's software prior to beginning the electrochemical process.

In some embodiments, the microprocessor system (111) may include a display screen to display system parameters and any alerts. In further embodiments, the microcontroller system (111) may be connected to a network of computers and may utilize a server to send notifications of the system parameters, including any alerts, to individuals or devices designated by the user in the microcontroller's software. Such alerts may be sent via electronic mail or may be sent via text message to a preprogrammed mobile communication device or electronic mail address. However, this is not required and in other embodiments, the microcontroller system (111) is configured in a closed network without a server and displays the system parameters and any alerts on a display screen located on the microcontroller system (111) itself.

In the embodiment depicted in FIG. 1, the method of electrochemical processing includes, after the article to be processed is suitably prepared, a suitable electrolyte solution is prepared in the tank, and the article is submerged into the electrolyte solution, a user inputting desired features or values or parameters, the microprocessor system (111) determining the system's target current levels, voltage levels, and processing time for the particular article being processed, as well as the system's safe operating thresholds, and applying power to the system to start the process. As the electrochemical process starts, with power flowing through the circuit depicted in FIG. 1 to the electrochemical cell (121), as described above, the microprocessor system (111) receives inputs from the various DC and AC current and voltage sensors (101), (103), (105), (107). (109), and (110), as described above, and adjusts the bias of the semiconductors (115) in the power output section (113) to control the system current at the target system operating value, while simultaneously monitoring the measured system parameters sensed by sensors (101), (103), (105), (107), (109), and (110), and, in some embodiments, displaying the monitored parameters on a display screen and sending alerts when a monitored parameter is approaching or exceeding a predetermined safe operating threshold.

The embodiment depicted in FIG. 1 is generally for use in an aluminum anodization process or an electroplating process. However, the disclosed systems and methods are not limited to such processes and could be used for other electrochemical processes, such as for electrowinning, and in alternative embodiments the disclosed systems and methods may be related to even other electrochemical processes. For example, in the embodiment depicted in FIG. 2, the disclosed systems may be used in a method of AC electrolytic anodization and in the embodiment depicted in FIG. 3, the disclosed system may be used in a method of continuous coil anodization.

In the alternative embodiment depicted in FIG. 2, the method of AC electrolytic anodizing is similar to the method disclosed in FIG. 1 and described above, except it generally generates a true synthesized purely AC waveform, as opposed to generating a DC carrier voltage with an AC modulation riding upon it. Like the embodiment depicted in FIG. 1, in the embodiment depicted in FIG. 2, power enters the system, goes through a rectification section (225), a surge and sag filter array (227), a noise snubbing filter array (229), and continues to flow through the circuit, through the depicted semiconductor arrays (215) and (217), to the cell (221). In the embodiment of FIG. 2, the system utilizes a positive and negative DC voltage rail, which may be generated by any of the three phase rectification methods discussed in relation to the embodiment of FIG. 1 or by any other positive and negative generating power supply that is capable of operating in concert to produce the positive and negative rails.

The positive and negative DC rails, which are the outputs of the rectification section (225) depicted in FIG. 2, may each be controlled through a method of power generation, such as through a diode network, through phase controlled firing of silicon controlled rectifiers (SCR rectifiers), through switch mode silicon devices, through a 12 pulse or 24 pulse, or through similar phase controlled mechanisms and/or switch mode power supplies, which may allow the system to operate in very high power operations. In the depicted embodiment, this is done by a phase controlled firing circuit, but in other embodiments, the positive and negative DC rails may be controlled by a switch mode operating power supply. The output of the positive DC rail may generate the positive half of an AC waveform and the output of the negative DC rail may generate the negative half of an AC waveform. These two half waveforms may be combined to create a synthesized AC waveform. The synthesized AC waveform created by the positive and negative DC voltage rails in the embodiment of FIG. 2 may be controlled in frequency and current density, as well as manipulated in other ways depending on the circumstances.

This is an improvement over existing methods of AC electrolytic anodizing, which generally use standard AC firing control to control current density by use of SCR's to chop or truncate a portion of the sine wave (i.e., the true AC waveform) to deliver the desired amount of current, and typically requires a higher voltage to do so. Rather than truncating a portion of the sine wave, the AC electrolytic anodizing method depicted in FIG. 2 uses a true AC waveform of appropriate voltage, which is known in the art to provide a finer and more consistent anodized finish.

The surge and sag filter array (227) and noise snubbing filter array (229) depicted in FIG. 2 generally have the same characteristics as described above in relation to the embodiment of FIG. 1. Similarly, the embodiment of FIG. 2, like the embodiment of FIG. 1, may include a plurality of AC and DC current and voltage sensors that measure the current and voltage at various points throughout the system, though the placement of these sensors may be different than the placement described for the embodiment of FIG. 1. For instance, as seen in the depicted embodiment, there is a DC current and DC voltage sensor positioned on the positive DC rail, and another DC current and voltage sensor positioned on the negative DC voltage rail. Similarly, there is an AC current (209) and AC voltage sensor (210) is positioned on the output line from positive and negative output to ground, as depicted in FIG. 2.

The embodiment depicted in FIG. 2 further may include at least one semiconductor array (215) on the positive DC voltage rail and at least one semiconductor array (217) on the negative DC voltage rail, both of which generally have the same characteristics and benefits as described above in relation to the embodiment depicted in FIG. 1. Further, the at least one semiconductor arrays (215) and (217) depicted in FIG. 2 may vary in size, configuration, and characteristics, depending on the needs and circumstances of the desired use. For instance, in some embodiments, arrays of semiconductors with the same characteristics may make up each at least one semiconductor arrays (215) and (217). In other embodiments, arrays of differing semiconductors may make up each at least one semiconductor arrays (215) and (217), such that small semiconductors may be utilized in one of the at least one semiconductor arrays (215) and (217), and large semiconductors may be utilized in a second of the at least one semiconductor arrays (215) and (217). In more embodiments, the at least one semiconductor array (215) may be a small semiconductor and the at least one semiconductor array (217) may be a large semiconductor, or vice versa.

Also like the embodiment depicted in FIG. 1, the current and voltage sensors (201), (203), (205), (207), (209), (210) depicted in FIG. 2 may provide input to the microcontroller system (211), including feedback on the current applied to the cell (221), which may be used within the microcontroller system (211) for comparing current generated to current applied to the cell (221), for safety features, record keeping, or control of the system, and the microcontroller system (211) may use these inputs to monitor system voltage and current and may control or maintain the bias of the depicted semiconductor devices (215) and (217) to control and maintain the desired output characteristics of the system in the same manner as described above in relation to the embodiment depicted in FIG. 1.

The embodiment shown in FIG. 3 depicts a system and method of continuous coil anodizing which may utilize the process disclosed in FIG. 1 and described above, except that the system of this alternative embodiment includes multiple cathodes and a ramp profile. In this alternative embodiment, a tank with a suitable electrolyte solution, i.e., a bath, (321) is prepared and a plurality of current control devices (333) submerged within the electrolyte solution. The current control devices (333) may be sacrificial cathodes or may be resistors or may be other suitable devices. Likewise, the configuration and placement of the current control devices (333) may vary based on the needs and circumstances of the user, as well as based on the characteristics of the material being anodized. In some embodiments, the placement of the current control devices (333) may be mechanically adjusted, either by hand or by motorized operation, depending on the needs and circumstances of the user.

After the electrolyte solution is prepared and the current control devices (333) are placed in their desired locations, as depicted in FIG. 3, the coil (301) to be anodized is submerged in the solution and the system and method depicted in FIG. 1 may be used to supply power and control the coil anodization process. Utilizing the method of the embodiment depicted in FIG. 1, a single power supply (123) may be used to supply current to multiple cathodes (333), each of which may be independently modulated for current flow. The modulation of current flow at different locations, i.e., the locations of the cathodes/current control devices (333), may simulate a ramp profile to the coil (301) being anodized as the coil (321) is moved past each cathode in succession towards the end of the bath (321).

The simulated ramp profile of the embodiment in FIG. 3 may be created by applying a steady voltage to the system and changing the resistance along the path the coil (301) moves in by utilizing a plurality of current devices (333) that decrease in resistance from the start of the bath (321) to the end of the bath (321), which may result in the system appearing to ramp up, or increase, the current. Slowly ramping up current is known to produce a higher quality and more consistent finish of anodized aluminum, as well as a thicker coating on the coil being anodized and a more consistent color; however, existing methods of coil anodization generally use a single power supply, a single cathode, and do not impart a ramp profile. Thus the alternative embodiment disclosed in FIG. 3 improves existing systems and methods of coil anodization and may result in a better quality product produced as compared to traditional coil anodization processes.

While the invention has been disclosed in conjunction with a description of certain embodiments, including those that are currently believed to be the preferred embodiments, the detailed description is intended to be illustrative and should not be understood to limit the scope of the present disclosure. As would be understood by one of ordinary skill in the art, embodiments other than those described in detail herein are encompassed by the present invention. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention.