Patent Application
20240372489
The present application relates generally to electric machine control. More specifically, control schemes and controller designs are described that smoothly pulse the operation of an electric machine during selected operating conditions to facilitate operating the electric machine in a more energy efficient manner.
The term “electric machine” as used herein is intended to be broadly construed to mean both electric motors and generators. Electric motors and generators are structurally very similar. Both include a stator having a number of poles and a rotor. When an electric machine is operating as a motor, it converts electrical energy into mechanical energy. When operating as a generator, the electric machine converts mechanical energy into electrical energy.
Electric motors and generators are used in a very wide variety of applications and under a wide variety of operating conditions. In general, many modern electric machines have relatively high energy conversion efficiencies. The energy conversion efficiency of most electric machines, however, can vary considerably based on their operational load. With many applications, an electric machine is required to operate under a wide variety of different operating load conditions. As a result, many electric machines operate at or near the highest levels of efficiency at certain times, while at other times, they operate at lower efficiency levels.
Battery powered electric vehicles provide a good example of an electric machine operating at a wide range of efficiency levels. During a typical drive cycle, an electrical vehicle will accelerate, cruise, decelerate, brake, corner, etc. Within certain rotor speed and/or torque ranges, the electric machine operates at or near its most efficient operating point, i.e., its “sweet spot”. Outside these ranges, the operation of an electric machine is less efficient. As driving conditions change, the electric machine transitions between high and low operating efficiency levels as the rotor speed and/or torque demand change. If the electric machine could be made to operate a greater proportion of a drive cycle in high efficiency operating regions, the range of the vehicle for a given battery charge level would be increased. Since the limited range of battery powered electric vehicles is a major commercial impediment to their use, extending the operating range of the vehicle is highly advantageous.
Although the energy conversion efficiency of conventional electric machines is generally good, there are continuing efforts to further improve energy conversion efficiencies over broader ranges of operating conditions.
A variety of methods, controllers, and electric machine systems are described that facilitate pulsed control of multiple electric machines (e.g., electric motors and generators) drive systems to improve the energy conversion efficiency of the electric machines when operating conditions warrant. More specifically, a method of controlling operation of at least a first electric machine of at least one electric machine on board a vehicle, wherein the vehicle has at least one resonance frequency is provided. A pulsed operation of the first electric machine is directed to deliver a desired average output, wherein the pulsed operation causes the first electric machine to alternate between a first output level that is greater than the desired average output and a second output level that is less than the desired average output. At least some transitions between the first output level and the second output level are controlled. At least one notch filter at the at least one resonance frequency of the vehicle is provided.
In another embodiment, a controller arranged to control at least a first electric machine of at least one electric machine on board a vehicle, wherein the vehicle has at least one resonance frequency is provided. A pulse controller is provided that directs a pulsed operation of the first electric machine, wherein the pulsed operation causes the first electric machine to alternate between a first output level that is greater than a desired average output and a second output level that is less than the desired average output. The pulse controller comprises a transition profile generator that controls transitions from the second output level to the first output level and a notch filter controller that provides at least one notch filter for the at least one resonance frequency.
In another manifestation, controller arranged to control at least a first electric machine of at least one electric machine on board a vehicle, wherein the vehicle has at least one resonance frequency is provided. A pulse controller is provided that directs a pulsed operation of the first electric machine, wherein the pulsed operation causes the first electric machine to alternate between a first output level that is greater than a desired average output and a second output level that is less than the desired average output. The pulse controller comprises a notch filter controller that provides at least one notch filter for the at least one resonance frequency.
In another manifestation, a method of controlling operation of a first electric machine of at least one electric machine on board a vehicle, wherein the vehicle has at least one resonance frequency is provided. A pulsed operation of the electric machine is directed to deliver a desired average output, wherein the pulsed operation causes the electric machine to alternate between a first output level that is greater than the desired average output and a second output level that is less than the desired average output. At least one notch filter at the at least one resonance frequency of the vehicle is provided.
These and other features of the present disclosure will be described in more detail below in the detailed description of the disclosure and in conjunction with the following figures.
The invention and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
In the drawings, like reference numerals are sometimes used to designate like structural elements. It should also be appreciated that the depictions in the figures are diagrammatic and not to scale.
The present application relates to pulsed control of a wide variety of electric machines (e.g., electric motors and generators) that would otherwise be operated in a continuous manner. Pulsed electric machine control is described in U.S. patent application Ser. Nos. 16/353,159 and 16/353,166 filed on Mar. 14, 2019, and Ser. No. 16/818,570 filed Mar. 13, 2020. Each of the foregoing applications is incorporated herein by reference in its entirety. As described in the incorporated applications, pulsed control of an electric machine offers the advantage of improving the operational energy conversion efficiency of the machine.
When pulsing is employed, there are frequent changes in the electric machine's commanded output. A potential drawback of pulsed control is that the frequent output transitions can increase the operational noise, vibration, and harshness (NVH) generated by the electric machine. The NVH issues associated with pulsing tend to be worse in electric machines having higher electrical time constants since the machine's electrical time constants may impose practical limitations on the frequency at which pulsing can occur. When pulsing frequencies are in frequency ranges that are generally perceptible to humans, the NVH concerns tend to be greater. Therefore, it is desirable to manage pulsing transitions in an effective and efficient manner.
The present application proposes the use of cubic or higher order pulse transition torque profiles in some electric machine pulsing applications and a notch filter to attenuate one or more resonance frequencies. In addition, some embodiments use pulsing frequencies that mitigate NVH. Such control can help mitigate NVH issues while managing transitions in an efficient manner. In some embodiments, quintic pulse transition profiles are used.
Referring to
The area under the peak-torque/speed curve 102 is mapped into a plurality of regions, each labeled by an operational efficiency percentage. For the particular electric machine shown, the following characteristics are evident:
The map 100 is for an internal permanent magnet synchronous electric machine. Specifically, it was derived from a traction motor used in a 2010 Toyota Prius. It should be understood that this map 100 is merely illustrative and should not be construed as limiting in any regard. A similar map can be generated for just about any electric machine, regardless of whether it is used in a vehicle or in some other application.
As can be seen from the map 100, when motoring, the electric machine is generally most efficient when operating within the speed and torque ranges of the sweet spot 104. If the operating conditions can be controlled so that the motor operates a greater proportion of the time at or near its sweet spot 104, the overall energy conversion efficiency of the motor can be significantly improved.
From a practical point of view, however, many driving situations dictate that the motor operates outside of the speed and torque ranges of the sweet spot 104. In electric vehicles, it is common to have no transmission or gearbox and as such have a fixed ratio of the electric motor rotation rate to the wheel rotation rate. In this case, the motor speed may vary between zero, when the vehicle is stopped, to a relatively high RPM when cruising at highway speeds. The torque requirements may also vary widely based on factors such as whether the vehicle is accelerating or decelerating, going uphill, going downhill, traveling on a level surface, braking, etc.
As also seen in
It should be appreciated that the electric machine would have a similar efficiency map that characterizes its efficiency when acting as a generator.
In
In the example illustrated in
On the other hand, when the desired motor torque is at or above the maximum efficiency curve, the motor may be operated in a conventional (continuous or non-pulsed) manner to deliver the desired torque. Pulsed operation thus offers the opportunity for efficiency gains when the motor is required to deliver an average torque below the peak efficiency torque for a given motor speed.
It should be noted that current and torque values and time scales provided herein are merely illustrative and are not intended to be limiting in any manner. In actual electric machine pulsing applications, the pulse duration used may widely vary based on the design needs of any particular system. In general, however, the scale of the periods for each pulse cycle is expected to be on the order of 10 μsec to 10 seconds (i.e., pulsing at a frequency in the range of 0.5 to 100,000 Hz), for example between 20 milliseconds to 2 second (0.5 to 5000 Hz). In some embodiments, the scale of the periods for each pulse cycle is expected to be on the order of 10 milliseconds to 2 seconds with a frequency range of 0.5 Hz to 100 Hz. Furthermore, there are a wide variety of different electric machines, and each machine has its own unique efficiency characteristics.
In
The electric machine controller 10 includes a power inverter 14, a pulse controller 30, and a torque modulation decision module 62. The power inverter 14 may be operated as a power inverter or power rectifier depending on the direction of energy flow through the system.
When the electric machine 12 is operated as a motor, the power inverter 14 is responsible for generating three-phase AC power (denoted as 18A, 18B, and 18C for phases A, B, and C respectively) from the DC power supply 16. The three-phased input power is applied to the windings of the stator of the electric machine 12 for generating a Rotating Magnetic Force (RMF). In an induction motor, this rotation field induces current to flow in the rotor winding which in turn induces a rotor magnetic field. The interaction of the rotor and stator magnetic fields generates an electromagnetic force (EMF) causing rotation of the rotor, which in turn rotates a motor shaft. The rotating shaft provides the output torque of the motor. For most common permanent magnetic motors, the rotor field is that of the permanent magnet.
The three phases, 18A-18C are each depicted by lines with arrows on both ends indicating that current can flow in either direction. When used as a motor, current flows from the power supply 16, through the power inverter 14, to the electric machine 12. When used as a generator, the current flows from the electric machine 12, through the power inverter 14, to the power supply 16. When operating as a generator, the power inverter 14 essentially operates as a power rectifier, and the AC power coming from the electric machine 12 is converted to DC power being stored in the DC power supply, such as a battery or capacitor.
The pulse controller 30 is responsible for selectively pulsing the three-phased sinusoidal input current signals 18A-18C to the electric machine 12. During conventional (i.e., continuous) operation, the three-phased input current provided to the electric machine 12 are continuous sinusoidal current signals, each 120° degrees out of phase with respect to one another. During pulsed operation, the three-phased sinusoidal current signals 18A-18C are selectively pulsed using any of the approaches described herein.
Referring to
In
When operating as a motor, the excitation current in
Returning to
When the torque demand is higher than the pulsing threshold, the torque modulation decision module 62 directs the electric machine 12 to operate in a continuous mode. In this case, torque demand is passed to the inverter 14 as inverter control signal 39 in a traditional manner, and the inverter 14 directs the operation of the electric machine in a continuous manner to deliver the desired torque.
When the torque demand is less than the pulsing threshold, the torque modulation decision module 62 determines the desired pulsed control operational state. The desired pulsed control operational state is passed via 32 to pulse controller 30 which then directs the operation of the inverter 14 via inverter control signal 38. In this context, the pulsing operational state may include an indication of whether pulsed control is enabled, and if so, (a) the desired target output level when during the torque on periods (sometimes referred to as the target pulse torque); (b) the desired pulsing duty cycle; and (c) whether the inverter should remain active or be deactivated during the no torque periods. In practice, the characteristics of the electric machine, the combination of the electric machine and its control system, and/or a larger system that includes the electric machine/machine controller may be characterized through the creation of operational maps such as the efficiency maps described above. Based on such maps, the most efficient operational state for any and all operating conditions (e.g., all possible machine speed and output level combinations) can be determined. In some embodiments, this information may be stored in a data structure such as a lookup table that may be utilized by torque modulation decision module 62 to determine the appropriate operating state for any commanded output (e.g., torque demand) based on the current machine speed, and any other relevant control parameters. In other embodiments, the torque modulation decision module 62 may use algorithmic or other suitable approaches to make such decisions.
The pulse controller 30 is responsible for controlling/directing the timing of the pulsing of electric machine 12 when a pulsed operation is called for. In the illustrated embodiment, the pulse controller 30 includes a frequency controller 33, a transition profile generator 34, and a notch filter controller 35. The frequency controller 33 receives vehicle frequency input 31. The vehicle input 31, such as vehicle speed or torque demand, may be data provided to the frequency controller 33 that the frequency controller 33 uses to determine the frequency of the pulses. The notch filter controller 35 receives vehicle resonance data 37.
When implementing pulsed electric machine control there are frequent transitions in commanded torque between a low value (normally zero) and a higher value having a higher energy conversion efficiency and vice versa. For best efficiency, the transition is preferably very quick. The benefit of this can be appreciated by reference to
In the example of pulsed control illustrated in
More specifically, when a voltage is first applied to a motor's windings, the buildup of the magnetic flux linkages, magnetizing (λdre) and motive (λqse), lag the applied voltage as in all inductive circuits. If the object of the control is to reach a target pulsing torque as rapidly as possible then the controller could theoretically compensate for the lagging magnetizing flux linkages by increasing iqse to achieve the demanded torque. This has the effect of increasing the applied current and hence increasing the motor and inverter losses which is counter to the object of pulsed control, minimizing the losses. Therefore, it is desirable to control the amplitude and phase of the applied current during the transitions to ensure that the transitions are made with minimal losses. Stated another way, during transitions, the flux linkages are preferably controlled such that they result in the most efficient overall solution for the torque equation.
Quick and efficient transitions are relatively easily achieved in motors/machines that have a relatively small time constant associated with building up the magnetic flux linkages required to support the target torque. However, as the time constants increase, the speed at which transitions can practically be achieved decreases-which limits the practical pulsing frequency. For example, the time constants associated with some induction motors are high enough such that pulsing at relatively low frequencies on the order of 0.5 to 20 Hz may be desirable. Humans are quite sensitive to vibrations in such frequency ranges which emphasizes the need to consider NVH issues in pulsed motor control.
To address the competing demands of quick transition times, energy efficient transitions, and mitigating NVH concerns, the present disclosure proposes the use of transition torque profiles having specific characteristics and with at least one notch filter. In various preferred embodiments, the commanded torque is smoothly but slowly transitioned from zero, then rapidly increased through most of the lower efficiency area, and finally slowly transitioned to the desired pulsing torque (e.g., a value at or near the peak efficiency torque for the current machine speed). In some embodiments, this is accomplished through the use of an S-shaped transition torque application profile. This approach has several advantages. These include:
One way to provide a smooth S-shaped curve is through the use of third order (cubic) transition torque request profile generation. Cubic control is sometimes referred to as “jerk” control in various control fields because in physics jerk is the third time derivative of position. Similarly, angular jerk is the third time derivative of angular momentum. In other embodiments, higher order functions such as quintic (5th order) or higher are used to generate the transition torque profiles. The specific torque profiles commanded by the pulse controller 30 during transitions are dictated by the transition profile generator 34. The specific transition torque profiles used in any specific operating conditions may be determined in any desired way. In some embodiments, the profiles are generated in real time algorithmically by the transition profile generator 34. In other embodiments, an appropriate lookup table or other suitable data structure may be provided so that the transition profile generator can simply look up the appropriate transition torque profile for the current operational state.
In the illustrated embodiment, when torque is initially applied, the angular jerk is set to a first value 611 and held constant for an initial period 610, as shown in
The transition from the target torque to the zero “off” period of pulsed control can be accomplished in a reciprocal manner. When the transition begins, at point 649, the jerk is set to a negative value 651 and held constant for a fifth period 650. During that period, the angular deceleration steadily increases 653 and the torque begins to slowly decrease 655. After the transitional fifth period 650, the jerk is set to zero 661 and held constant for a sixth period labeled 660. In that period 660, the angular deceleration remains constant (663 in
In general, the goal is to ensure that the total torque delivered in a pulse (the area 600 under the torque pulse curve 601 in
It should be apparent that the example of
Although the described jerk based torque profile generation can significantly mitigate NVH in many applications, even further improvements can be attained by using higher order control in some circumstances. More specifically, a feature of the illustrated jerk based control is that there will be abrupt changes in the resultant angular acceleration (i.e., corners in the context of calculus) as seen in
Quintic profile generation is diagrammatically illustrated in
A noteworthy characteristic of quintic profile generation schemes is that by definition, there are no abrupt changes (corners) or discontinuities in the angular acceleration (
In the quintic torque profile generation example shown in
There are a number of other factors to be considered in determining when pulsing is advantageous and desirable and some of those may be influenced by the transition control scheme employed by the transition profile generator 34 (e.g., step changes in requested torque, cubic profile generation, quintic profile generation, etc.)
The nature of some of those factors can be appreciated through an understanding of the nature of higher order torque profile generation. For example, if the pulsing duty cycle becomes too high relative to transition time, pulsed control could lead to a circumstance where the commanded torque never actually gets reduced to zero. Such a circumstance is diagrammatically illustrated in
Conversely, when the pulsing duty cycle becomes too low relative to the transition time, situations can occur in which the commanded torque never actually reaches the target pulsing torque. This situation is diagrammatically illustrated in
In the embodiment illustrated in
The pulsing frequency at which the power is pulsed may be determined by the torque modulation decision module 62 or the frequency controller 33 in the pulse controller 30. In some embodiments, the pulsing frequency can be fixed for all operations of the electric machine, while in others it may vary based on operational conditions such as machine speed, torque requirements, etc. For example, in some embodiments, the pulsing frequency can be determined through the use of a look-up table. In other embodiments, the pulsing frequency is not necessarily fixed for any given operating conditions and may vary as dictated by the frequency controller. This type of variation is common when using sigma delta conversion in the determination of the pulses as in the incorporated patent application. U.S. patent application Ser. No. 17/158,230, filed on Jan. 26, 2021, incorporated by reference for all purposes, provides some of the conditions that may be used to determine pulsing frequency based on Noise, Vibration, and Harshness (NVH). Such conditions may be either caused by a measurable parameter of the vehicle or a feature on the vehicle that adjusts an amount of the NVH that is acceptable. Specific examples of such conditions are at least one of gearbox status, wheel drive status, weight of the load carried by the vehicle, selectable economy mode, selectable sport mode, selectable NVH controller that allows the driver to select different levels of acceptable NVH, occupancy, temperature, a first model that models NVH characteristics of the vehicle as the vehicle ages, active noise control, active vibration control, and road condition. In some embodiments, the selected transition is dependent on the selected pulsing frequency.
The pulsing frequency generates excitations at the fundamental frequency and harmonics of the pulsing frequency.
Therefore, various embodiments provide at least one notch filter near at least one or more resonance frequencies of the vehicle.
For purposes of increased efficiency with dynamic motor drive operation, it may be desirable to completely shut off the power inverter 14. This would bring the electromagnetic torque during the ‘off’ period to zero. In this case, it would not be possible to control the motor torque to the notch-filtered value. But the notch-filtered torque command can still be utilized during the “on” portion of the pulse. The
Some electric vehicles have more than one motor. For example, an electric vehicle may have three or more motors.
In some embodiments, the notch filters are provided by hardware. Such notch filters would be difficult to adjust and would be used for vehicle resonance frequencies that are constant. In some embodiments, the notch filter is adjustable using software. Such notch filters may be dynamically changed and would be used for either constant or variable vehicle resonance frequencies. Vehicle resonance data 37 providing resonance frequencies of the vehicle is supplied to the pulse controller 30. The notch filter controller 35 provides one or more notch filters at one or more of the resonance frequencies of the vehicle. Notch filter characteristic can be defined by a target frequency and a q-factor or may be defined by a center frequency and a desired bandwidth to be filtered. The vehicle resonance data 37 may be data in a lookup table or may be data received from a vibration sensor. The vehicle resonance data 37 is used to determine the desired notch filter characteristic. The vehicle resonance frequencies may change depending on various parameters of the vehicle or settings by a user, such as gearbox status, wheel drive status, weight of the load carried by the vehicle, selectable economy mode, selectable sport mode, selectable NVH controller that allows the driver to select different levels of acceptable NVH, occupancy, temperature, a first model that models NVH characteristics of the vehicle as the vehicle ages, active noise control, active vibration control, and road condition.
Although some illustrative embodiments of notch filters provide 40 to 60 dB of attenuation of a target frequency, some embodiments may provide lower attenuation resulting in small visible fluctuation of the filtered curves.
During pulsed operation of the electric machine 12, the inverter is activated during pulses and is ideally deactivated between pulses. Deactivating the inverter is conceptually desirable because it helps reduce inverter losses and inverter induced losses during the no torque periods. However, there are times when it will be desirable to have the inverter actively command zero torque during the no torque periods (or at least a portion of the no torque periods). There are several reasons for this. One of the easiest to appreciate relates to back electromotive force (BEMF). When the BEMF of a permanent magnet motor exceeds the power supply voltage 16 used by the motor, a retarding torque is generated that can significantly degrade the motor's efficiency. Field weakening is typically used to mitigate or eliminate the retarding torque. BEMF generated by a motor is primarily a function of motor speed. Therefore BEMF remains an issue during the no torque periods of pulsed motor control. Since field weakening is applied by the inverter, deactivating the inverter during the no torque periods of pulsed control in operating states of a motor in which field weakening is desired would have the effect of allowing BEMF to retard the motor during those periods thereby reducing the motor's overall efficiency (sometimes quite significantly). To mitigate these effects, the inverter is preferably left on commanding a zero torque during the no torque periods of pulsed control in operating regions where the BEMF exceeds the supply voltage. Of course, there may be other circumstances where it is desirable to maintain the inverter on during the no torque periods of pulsed operation. In various embodiments, the pulse controller 30 or the torque modulation decision module 62 may direct the inverter 14 to turn off when desired. The pulse controller 30 controls transitions between a first output level and a second output level to allow pulsed transitions between a first torque and a second torque.
Although only a few embodiments of the invention have been described in detail, it should be appreciated that the invention may be implemented in many other forms without departing from the spirit or scope of the invention. For example, although cubic and higher order function generation is described for generating the torque transition profiles, it should be appreciated that smooth S-shaped transition profiles that eliminate discontinuities in the angular acceleration or eliminate both discontinuities and corners in the angular acceleration may be generated in other ways as well.
Most of the discussion above focuses on controlling the torque during transitions and therefore refers to controlling the transition torque profile. As will be appreciated by those familiar with motor control, the same or similar results can be accomplished by controlling the current in the same manner (i.e., using cubic or higher order transition profiles). As such, it should be appreciated that unless the context requires otherwise, the claimed transition management may be applied regardless of what parameter is actually controlled by the controller.
The various described machine controller components including the torque modulation decision module, the pulse controller, the transition profile generator, the inverter controller, the notch filter controller, the frequency controller, and other control elements may be implemented, grouped, and configured in a wide variety of different architectures in different embodiments. For example, in some embodiments, the pulse controller may be incorporated into a motor controller or an inverter controller or it may be provided as a separate component. Similarly, for a generator, the pulse controller may be incorporated into a generator controller or a rectifier controller, and in combined motor/generators, the pulse controller may be incorporated into a combined motor/generator controller or a combined inverter/rectifier controller. In some embodiments, the described control functionality may be implemented algorithmically in software or firmware executed on a processor-which may take any suitable form, including, for example, general purpose processors and microprocessors, DSPs, etc.
The pulse controller may be part of a larger control system. For example, in vehicular applications, the pulse controller may be part of a vehicle controller, a powertrain controller, a hybrid powertrain controller, or an ECU (engine control unit), etc. that performs a variety of functions related to vehicle control. In such applications, the vehicle or other relevant controller, etc. may take the form of a single processor that executes all of the required control, or it may include multiple processors that are co-located as part of a powertrain or vehicle control module or that are distributed at various locations within the vehicle. The specific functionalities performed by any one of the processors or control units may be widely varied.
The invention has been described primarily in the context of motor control and/or inverter/motor control. However, it should be appreciated that the described approach is equally applicable to generator and/or generator/rectifier control. Thus, any time that motor control is described it should be appreciated that analogous techniques can be applied to generator control. Thus, unless the context requires a different interpretation, a description of a feature of pulsed motor control, pulsed generator control, or pulsed motor/generator control should be understood to apply equally to pulsed motor control, pulsed generator control, and the pulsed control of combined motor/generators.
A variety of different control schemes can be implemented within the pulse controller. Generally, the control schemes may be implemented digitally, algorithmically, using analog components, or using hybrid approaches. The pulse generator and/or the motor controller may be implemented as code executing on a processor, on programmable logic such as an FPGA (field programmable gate array), in circuitry such as an ASIC (application specific integrated circuit), on a digital signal processor (DSP), using analog components, or any other suitable piece of hardware. In some implementations, the described control schemes may be incorporated into object code to be executed on a digital signal processor (DSP) incorporated into an inverter controller (and/or rectifier controller in the context of a generator and/or a combined inverter/rectifier controller).
In various embodiments, pulse width modulation, sigma-delta conversion, or other techniques may be used to create the pulsed inverter control signal 38. Regardless of the type of modulation used, the transitions between pulsing levels may be managed in the described manner. Similarly, the described pulse transition management may be used on any type of motor in which pulsed control is used regardless of the machine's time constant and/or the switching frequency used. Therefore, the present embodiments should be considered illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope and equivalents of the appended claims.
While this disclosure has been described in terms of several preferred embodiments, there are alterations, modifications, permutations, and various substitute equivalents, which fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present disclosure. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and various substitute equivalents as fall within the true spirit and scope of the present disclosure. As used herein, the phrase “A, B, or C” should be construed to mean a logical (“A OR B OR C”), using a non-exclusive logical “OR,” and should not be construed to mean ‘only one of A or B or C. Each step within a process may be an optional step and is not required. Different embodiments may have one or more steps removed or may provide steps in a different order. In addition, various embodiments may provide different steps simultaneously instead of sequentially.
This application claims the benefit of priority of U.S. Application No. 63/500,493, filed May 5, 2023, which is incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63500493 | May 2023 | US |
