System and method for wireless battery charging using circuit modeling

Abstract

A system for wirelessly charging a battery includes a switch operatively coupled to a power source. An inductive element (which may be part of a transformer element (which may be part of a filter)) is in operative communication with the switch. A transformer is formed when two inductive elements are placed in close proximity to provide a wireless charging interface. The system includes a processor in communication with the switch and in communication with a model of an inductor, which may include the transformer. The processor is configured to generate a shaped charging waveform in response to executing the model by controlling the switch through execution of instructions to generate a train of pulses at the inductor to generate a shaped charging waveform.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This PCT application is related to and claims priority to U.S. patent application Ser. No. 63 / 311,751, entitled "Systems and Methods for Wireless Battery Charging Using Circuit Modeling," filed on February 18, 2022, the entire contents of which are incorporated herein by reference for all purposes.

[0002] Embodiments of the present invention relate generally to systems and methods for wirelessly charging a battery, and more particularly to systems and methods for generating a shaped charging signal that includes a wireless interface between a charger and a device. The charger may include a model of the circuit components (including the wireless interface) involved in shaping the signal and / or filtering unwanted frequency components from the signal prior to application to the battery. [Background technology]

[0003] Countless different types of motorized devices, such as power tools, mobile computing and communication devices, portable electronic devices, and all kinds of motorized vehicles, including scooters and bicycles, use rechargeable batteries as their operating power source. Rechargeable batteries are constrained by a finite battery capacity and must be recharged when depleted. Recharging a battery can be inconvenient because the motorized device must often not be moved during the time it takes to recharge. Depending on the size of the battery, recharging can take several hours. Furthermore, charging a battery is often accompanied by a degradation of the battery performance. For this reason, significant efforts have been made to develop battery charging techniques to, among other things, reduce the time it takes to recharge a battery, improve battery performance, and reduce battery degradation due to charging.

[0004] It is with these observations, among others, in mind that the various aspects of the present disclosure have been conceived. Summary of the Invention

[0005] Aspects of the disclosure include a system for wirelessly charging a battery, comprising a first switch operatively coupled to a power source. The system further includes a first inductive element, which may be an inductor, multiple inductors coupled in series, parallel, or a combination thereof, a transformer, such as a primary or secondary winding of a transformer, or an inductive portion of a transformer, among other possible inductive elements, in operative communication with the first switch. The system further includes a processor in communication with the switch and in communication with a model of the inductive element. Additional components may also be modeled. The processor is configured to generate a shaped charging waveform in response to executing the model to generate a shaped charging waveform by generating a pulse train at the first inductive element by controlling the switch through execution of instructions.

[0006] In one configuration specifically configured for wireless charging, an embodiment includes a switch and a transformer in operative communication with the switch, a processor of some form in communication with the switch and in communication with a model of the transformer, the processor configured to generate a shaped charging waveform in response to executing the model to generate a train of pulses in the transformer by controlling the switch by executing instructions to generate a shaped charging waveform, which is then applied to a battery.

[0007] The transformer may be formed by a first inductor that may be on the charger side of the system and a second inductor that may be on the equipment (including the battery to be charged) side of the system. The adjacent arrangement of the inductors (which may include an air gap between them) forms the transformer. As will be appreciated, the transformer may have a variety of possible configurations depending on the arrangement, number, turns, relative turns, etc. between the inductors on either side of the configuration.

[0008] In various aspects, the processor may be further configured to execute the pulse train according to the model and adjust the pulse train to generate a shaped waveform. Other characteristics may also be modeled. In one example, the model may include a configurable inductance value and a configurable resistance value to represent at least a transformer. The processor may be further configured to execute the instructions to apply a known signal to the transformer and obtain a first measurement (e.g., current or voltage) at a first point of the known signal and a second measurement (e.g., current or voltage) at a second point of the known signal, and calibrate the model by changing at least one of the configurable inductance value or the configurable resistance value if at least one of the first measurement at the first point or the second measurement at the second point does not match the first target measurement at the first point or the second target measurement at the second point, respectively.

[0009] In various contemplated embodiments, the battery may be operatively coupled to a transformer, or more generally, a filter, to receive the shaped charging waveform. In various embodiments, the charging waveform is shaped and does not employ a traditional constant current or constant voltage type charging signal, although it is contemplated that the signal may be shaped as a constant signal.

[0010] In another aspect, a capacitor may be operatively coupled to the power source and the first switch, the capacitor constructed and arranged to deliver energy (e.g., a shaping current) through the switch to generate a shaped charging waveform through the transformer and to be a modeled element of the system.

[0011] In another aspect of the disclosure, a method of charging a battery includes generating a shaped charging waveform in response to executing the model by a processor in communication with a switch and a model of a filter including a transformer coupled to the switch to generate a shaped charging waveform by generating a pulse train at the filter under control of the switch. The method may further include generating a known signal from the filter by generating the pulse train at the filter element, and calibrating the model by adjusting at least one attribute of the model if a measured attribute of the known signal does not match a target measurement result.

[0012] In yet another aspect, a system for charging a battery includes a first switch receiving power over a wireless interface. The system also includes a first inductor in operative communication with the switch. The system further includes a processor in communication with the first switch and in communication with a model including the first inductor, the processor configured to generate a shaped charging waveform in response to executing the model by controlling the switch by executing instructions to generate a train of pulses at the first inductor to generate a shaped charging waveform.

[0013] These and other aspects of the disclosure are described in greater detail below.

[0014] Various objects, features, and advantages of the disclosure described herein will become apparent from the following description of embodiments of the respective inventive concepts, as illustrated in the accompanying drawings. It should be noted that the drawings are not necessarily to scale and may depict various features of an embodiment, with emphasis instead being placed on illustrating the principles and other aspects of the inventive concepts. Also, the same reference characters may represent the same or similar parts throughout the different views of the figures. The embodiments and drawings disclosed herein are intended to be considered illustrative, and not limiting. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a system diagram of a wireless charging system, according to one embodiment. [Diagram 2] 1 is a signal graph of an example of a controlled, arbitrary-shape charging waveform for charging a battery, according to one embodiment. [Diagram 3] FIG. 2 is a schematic diagram illustrating a circuit for wirelessly charging a battery, according to another embodiment. [Figure 4] FIG. 13 is a schematic diagram illustrating an alternative circuit for wirelessly charging a battery, according to another embodiment. [Figure 5A-C] FIG. 2 illustrates an example of a wireless charging system that generates a charging signal, according to one embodiment. [Figure 5D] FIG. 2 illustrates an example of a wireless charging system that generates a charging signal, according to one embodiment. [Figure 5E] FIG. 2 illustrates an example of a wireless charging system that generates a charging signal, according to one embodiment. [Figure 5F] FIG. 2 illustrates an example of a wireless charging system that generates a charging signal, according to one embodiment. [Figure 5G] FIG. 2 illustrates an example of a wireless charging system that generates a charging signal, according to one embodiment. [Figure 6] FIG. 2 illustrates an example of a charging signal generated in a transformer of the filter circuit based on a model of the filter circuit. [Figure 7] FIG. 13 illustrates an example of a test signal used to calibrate a model. [Figure 8] FIG. 1 is a system diagram of a wireless charging arrangement according to one embodiment. [Figure 9] FIG. 2 is a system diagram illustrating a wireless charging configuration in which the wireless interface is distinct from the circuit element(s) that shape the charging signal, according to one embodiment. [Figure 10] FIG. 1 illustrates an example of a computer system that can be used to implement embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Disclosed herein are systems, circuits, and methods for wirelessly charging (recharging) batteries. In this specification, the terms charging and recharging are used interchangeably. Aspects of the present disclosure may provide multiple advantages, either alone or in combination, over traditional wired charging. These advantages and benefits may be realized, among other things, through a wireless interface, where charging energy is transferred wirelessly. In so-called wired charging, charging energy is transferred through a physical medium ("wire") between a power source and the battery to be charged.

[0017] In addition to not requiring a traditional wired connection, the wireless charging system described herein can also generate traditional charging signals such as constant current, constant voltage, and a combination of constant current and constant voltage (considered a direct current (DC) charging signal), or non-traditional (non-DC) charging signals that provide multiple benefits over traditional similar DC charging techniques. For example, the charging techniques described herein may have multiple follow-on effects such as reducing the rate at which the anode is damaged and reducing heat generation during charging, thereby reducing damage to the electrodes and other batteries, reducing the risk of fire or short circuit. In another example, the charging techniques described herein may allow for a higher charging rate to be applied to the battery, thus allowing for faster charging. Conversely, the systems, circuits, and methods described may require less energy to charge the battery compared to various forms of traditional charging circuits and methods. All of these techniques can optimize the charging rate used, taking into account other issues such as cycle life and temperature. In one example, optimizing the charging rate and parameters can provide longer battery life and higher charging energy efficiency.

[0018] In some embodiments discussed, a system is described that may wirelessly charge a battery and generate a controllably shaped charging signal using a model of one or more components of a charging signal shaping circuit. Part of the shaping circuit may include a wireless interface between the charger and the battery to be charged or a device that includes the battery. Conventional charging techniques such as constant current or constant voltage do not involve shaping of the charging signal and are therefore relatively simple to control and do not require the modeling techniques discussed herein, or more generally, modeling techniques that shape the charging signal.

[0019] In one embodiment, the charging signal shaping algorithm may provide a circuit model with an expected or target charging signal for charging the battery. The model may be used to verify and / or adjust the control for generating the signal. The model may also output one or more control signals to one or other components of the charging signal shaping circuit based on the target charging signal and based on modeling of the components of the charging signal shaping circuit. While in some cases aspects of the shape of the shaped charging signal may correspond to a harmonic (or multiple harmonics) associated with optimal transfer of energy to the battery, the objective of the system, among other objectives, is to efficiently generate and apply a shaped charging signal (which may be of any shape determined or prescribed by the system) to the battery. The prescribed and / or controlled shape may include the contents of the charging signal or may be any shape prescribed by the control. The control signals to the components of the charging signal shaping circuit may be based on models of the components of the shaping circuit, including the wireless interface components, rather than strictly based on feedback of measurements of the charging signal at the battery being charged or the battery itself, such as voltages and currents representative of the battery charging circuit. In some cases, this approach is referred to as a "feed-forward" technique.

[0020] This feed-forward technique, which utilizes a model of the circuit to determine a control signal for defining the charging signal, may provide several advantages, including accuracy and speed of signal conditioning. Additionally, this configuration may operate with fewer components and / or processing overhead compared to other approaches, such as strict feedback approaches, resulting in lower cost, less printed circuit board (PCB) area, and simpler computations, among other advantages.

[0021] In practice, it is difficult to rely solely on a model of the circuit without some type of feedback to, among other things, adjust for model errors, component drift, effects on circuit components such as temperature, changes in the battery, and periodically provide additional data to the model to modify parameters and / or outputs. For example, during operation of the charging circuit, aspects of the battery may change during charging in response to state of charge (SoC), state of health (SoH), etc. Thus, in some cases, aspects of the battery may be obtained and utilized to adjust the model of the circuit. The model may account for various components of the circuit used to shape and filter the charging signal. Values ​​and functions of these components change over time, and such changes may be accounted for in the model. In general, modeling of the circuit provides estimates and pre-determinations of the charging signal to counter the relatively slow feedback paths from the battery and other sensors. The feedback paths may also be wireless, which may affect the speed at which information is shared with the charger. Additionally or alternatively, modeling provides a mechanism by which effective signal control may be achieved without, among other things, complex signal measurements, component measurements, or other feedback mechanisms that are costly and consume valuable power and PCB area. Model updates based on feedback information may nevertheless adjust the model's response based on changes in the battery and / or circuit elements. Furthermore, some wireless charging embodiments may not include a model.

[0022] The term "battery" can be used in various ways in the art and herein to refer to individual cells having an anode and a cathode separated by an electrolyte (solid or liquid), as well as collections of such cells connected in various configurations. A battery or battery cell is a form of electrochemical device. A battery typically includes repeating units of opposing charge sources and electrode layers separated by an ionically conductive barrier (often a liquid or polymer membrane saturated with an electrolyte). These layers are constructed to be thin, allowing multiple units to occupy the volume of the battery, and each stack of units increases the available power of the battery. Although many examples are discussed herein as being applicable to batteries, it should be understood that the systems and methods described may be applied to many different types of batteries, ranging from individual cells to batteries including various possible interconnections of cells, such as cells coupled in parallel, series, and series-parallel. For example, the systems and methods discussed herein may be applied to battery packs including many cells arranged to provide a specified pack voltage, output current, and / or capacity. Additionally, the embodiments discussed herein may be applied to different types of electrochemical devices, such as, by way of example, various different types of lithium batteries (including, but not limited to, lithium metal and lithium ion batteries), lead acid batteries, various types of nickel batteries, and solid-state batteries of various possible chemistries. The various embodiments discussed herein may also be applied to battery configurations of various structures, such as button or "coin" type batteries, cylindrical cells, pouch cells, and prismatic cells.

[0023] FIG. 1 is a schematic diagram illustrating an exemplary charging signal generator configuration 100 for wirelessly charging a battery 104. The generator includes a processing unit 106, which may comprise a controller 108, such as a microcontroller, FPGA (field programmable gate array), ASIC (application specific integrated circuit), microprocessor, state machine, combinations thereof, or other processing configurations, that provides control for generating a charging signal by a charging signal shaping unit 110 and controls charging via a wireless interface filter 112. The controller is in communication with a model 114 of the components of the charging signal shaping unit and / or the wireless interface filter to generate control instructions to the charging signal shaping unit. The processing unit 106 may include discrete parts providing the controller, model, and shaping unit (e.g., an integrated unit), or various combinations of these may be provided in separate devices. Thus, although the processing unit 106 is shown as including a controller 108, in some examples the processing unit is the controller. The system may receive battery measurements from battery measurement circuitry 116, such as current and / or voltage measurements at the battery terminals of the battery 104 in the presence of a charging or calibration signal, for use in calibrating or adjusting a model or to affect charging control. The battery measurement circuitry may be associated with a part of a battery pack or module for a device that includes or is powered by a battery.

[0024] The battery measurements may be wirelessly communicated to the generator 106. In general, the generator may include or be operatively coupled to a power source 118, which may be a voltage source or a current source. In one embodiment, the power source 118 is a direct current (DC) source, but an alternating current (AC) source is also contemplated, and may further include rectification to convert the AC source signal to a DC source signal. Thus, in various options, the power source 118 may include a DC source that provides a unidirectional current, an AC source that provides a bidirectional current, or a source that provides a ripple current (such as an AC signal that is DC biased so that the current is unidirectional). In general, the power source 118 provides charging energy (e.g., current) that may be shaped by the control unit 106 and filter components to generate a controllably shaped charging signal for charging the battery 104. In one example, the circuit controller 108 may provide one or more inputs to a power signal shaping circuit to generate pulses to the wireless interface filter 112, which converts the pulses into a shaped charging signal to the battery and generated at the output of the filter. In general, a filter converts a pulse train into a shaped waveform. In various examples discussed herein, one embodiment of the filter includes an inductor, which may be a coil of a transformer formed in the wireless interface. Other components of the filter may include various possible shunt capacitors, a second inductor, and other components shown in various examples herein.

[0025] In some cases, the charging signal shaping circuit 110 may modify energy from the power source 118 to generate a charging signal shaped based on the state of charge at the battery 104, such as a charging signal that corresponds at least in part to one or more harmonics based on the impedance when a signal including the harmonics or attributes of the harmonics is applied to the battery 104. In an example such as FIG. 1, the circuit 100 may include a battery measurement circuit 116 connected to the battery 104 to measure cell voltage and / or charging current as well as other battery attributes such as temperature and to measure or calculate the impedance of the battery 104. In one example, the battery characteristics may be measured based on the applied charging signal. In another example, the battery characteristics (which may include impedance response or other similar measures such as admittance) may be measured as part of a routine to characterize the battery by applying a signal with varying harmonic frequency attributes to generate a range of battery cell characteristic values ​​associated with different frequency attributes, which may be performed before, during, or periodically during charging, and may be used in combination with probing and other techniques. Battery characteristics may change based on many physical or chemical characteristics of the battery, including the battery's state of charge and / or temperature. Thus, the battery measurement circuit 116 may be controlled by the circuit controller 106 to, among other things, determine various battery characteristics of the battery 104 during recharging and provide the battery characteristic measurements to the circuit controller 108 or other portions of the generator 100.

[0026] The circuit controller 108 may generate a target charging signal for efficient charging of the battery 104. For example, the circuit controller 108 may generate a charging signal with attributes corresponding to harmonics associated with a minimum impedance value of the battery 104 using a signal definition characterized by an understanding of the measured impedance of the battery 104 or the impedance effect of the signal on the battery. To this end, the circuit controller 108 may execute a charging signal algorithm that outputs a shape of the charging signal based on the measured, characterized, and / or estimated state of charge of the battery 104. The circuit controller 108 may then generate one or more control signals based on the charging signal algorithm and provide these control signals to the charging signal shaping unit 110. The control signals may, among other functions, shape the charging signal to approximate the shaped charging signal determined by the algorithm. The charging signal shaping circuit (or, more particularly, the wireless interface filter) may further filter any unwanted frequency attributes from the signal. In some cases, the shaped charging signal may be a charging signal of any shape that does not conform to a conventional repetitive charging signal, such as a repetitive square wave or triangular wave charging signal.

[0027] For example, FIG. 2 is a signal diagram 202 of a shaped battery charging signal 200 for charging the battery 104. The shape can be anything, but of course can be controlled and can be a variety of shapes depending on the control. The signal diagram 202 shows a charging signal 208 graphed as an input current 204 versus time 206. The shape of the charging signal 208 can be determined by a charging signal algorithm or program executed by the circuit controller 106. In one example, the shape of the charging signal 208 can be based on characteristics of the battery cell, such as a frequency or harmonic associated with an impedance value (which may be a minimum impedance) of the battery cell 104. In some examples, various portions of the shape are based on the impedance response of different harmonics, among others. In many examples, the shape is based on a harmonic at or around the lowest impedance, but is not limited to the harmonic of the lowest impedance. For example, a leading edge 212 of the shape can correspond to a particular harmonic. In some cases, a signal such as that shown in FIG. 2 may be a repeating sequence of such signals (e.g., 208(a)-208(n)) between periods when little or no charging current 210 is applied to the battery and periods when charging current (e.g., signal 208(a) or 208(n)) is applied to the battery. In yet another example, various aspects of the shape of the charging signal 208 may correspond to harmonics associated with one or both of the conductance or susceptance of the admittance of the battery 104. When considering impedance values, the techniques evaluate harmonic values ​​whose values, alone or in combination, are relatively low impedance. These techniques evaluate harmonics whose admittances, consisting of conductance and susceptance, alone or in combination, are relatively high by admittance. Given the approximate inverse relationship, the term impedance as used herein may include its inverse, admittance. In general, the charge signal shaping algorithm of the generator 100 may modify or otherwise determine the shape of the charge signal 208 based on any characteristic (measured, modeled, or estimated) of the battery 104 .

[0028] Pulse charging has been investigated in some conventional charging scenarios. However, it has been found that applying a square-wave pulse charging signal to charge a battery can shorten the battery's lifespan or result in inefficient charging of the battery. For example, the sudden application of a charging current (e.g., the sharp leading edge of a square-wave pulse) to a battery electrode (usually the anode) can cause a large initial impedance between the battery's terminals, resulting in no power being transferred to the battery, causing, among other problems, a decrease in the efficiency of the charging process and / or damage to parts of the battery being charged.

[0029] The rapid change of the charging signal to the battery due to the square wave pulse can also result in noise consisting of high frequency harmonics, such as at the leading edge of the square wave pulse, the trailing edge of the square wave pulse, and during the use of conventional reverse pulse schemes. Such large harmonics result in high impedance at the electrodes of the battery. Such high impedance can result in many inefficiencies and degradation of the battery, including capacity loss, heat generation, imbalance of electrokinetic effects throughout the battery, undesirable electrochemical responses at the charging interface, and degradation of materials within the battery that can damage the battery and shorten the battery life. Furthermore, cold starting a battery with pulses with sharp bonding edges initiates capacitive charging and diffusion processes, thereby limiting faradaic action. During this time, proximal lithium reacts and is rapidly consumed, leaving undesirable side reactions and diffusion-limited conditions that adversely affect the health of the cell and its components. These and other inefficiencies are particularly detrimental when recharging a battery at the relatively large currents typically associated with so-called fast charging.

[0030] For these and various other reasons, the shaped charging signal, when applied in the particular temperature window in which charging can occur, is not a square wave, nor is it a square edge pulse or pulse train that contains one or more very high frequency harmonics.

[0031] The shape of the charging signal 208 may change over time as the characteristics of the battery 104 may change due to state of charge, temperature, and other factors. The signal may be defined in part with reference to a model 114 of the circuit components involved in generating the signal and / or filtering the signal. Note that wireless interface components may be involved in filtering or defining and shaping the charging signal. Wireless feedback may also be used in the system. Thus, in some cases, the generator may perform an iterative process to monitor or determine characteristics of the circuit and / or battery and adjust the model and / or shape of the charging signal 208 applied to the battery accordingly. The iterative process may improve the accuracy of the signal shape and / or the efficiency of the charging signal used to recharge the battery, thereby reducing the time to recharge the battery, extending the life of the battery (e.g., the number of charge / discharge cycles the battery can undergo), optimizing the amount of current that charges the battery, and avoiding energy loss due to various inefficiencies, among other benefits.

[0032] 3 is a schematic diagram of a circuit 300 for charging a battery 304 by generating a charging signal using a switching element 312 to generate a controlled initial pulse train at node 336, which is then converted by a filter component 324 into a shaped charging signal that is applied to the battery, according to one embodiment. The filter also provides a wireless interface, as discussed below. The circuit 300 includes the elements introduced above with reference to the generator of FIG. 1, including a power source 302, a circuit controller 306, a battery measurement circuit 308, and a battery 304.

[0033] In the example of FIG. 3, the filter component may comprise a wireless interface including a first inductor 316 and a second inductor 318. The first inductor is part of a charging device 340 that may house the first inductor. The charging device may further comprise a switch 312, a circuit controller 306, and may be coupled to or include a power source 302. The second inductor 318 may be part of a device 342 that includes a battery 304 to be charged, or may be part of a battery module (including a battery) that may be operatively coupled to such a device to power it. When the inductors are placed in operative proximity and alignment, they may together constitute a transformer and act to provide inductive charging. Here, there is no physical connection, such as a wire, between the inductors. Instead, the inductors are placed in close proximity to each other, so the technology is considered wireless.

[0034] Other elements shown in circuit 300 of FIG. 3 may be included in the charge signal shaping circuit and / or filter of FIG. 1. As described in more detail below, circuit controller 306 may provide one or more control signals 330 to switches of circuit 300 as part of the process of shaping a current or voltage signal to charge battery 304 in cooperation with a circuit model. Circuit controller 306 may be implemented with an FPGA device, a microcontroller, a processor, an ASIC, or any other programmable processing device. In one embodiment, circuit controller 306 may include a charge signal shaping generator 310 that controls the switches to generate a pulse train at node 336 that generates the shape of the charge signal applied to battery 304.

[0035] As introduced above, the generator may use a model rather than an extensive feedback environment using detailed feedback of various signals and battery characteristics. At a simple level, the model is of an inductor in series with a resistor representing a transformer formed by the relative placement of the inductor and the resistance of the filter circuit 324 and the battery 304. Thus, the model may be an inductance value in series with a resistance value. In the presence of a controlled pulse train at the input to the model, the model can predict the charging signal output to the battery. Thus, for example, a pulse train at node 336 can generate a signal as shown in FIG. 2 at the input 338 to the battery. In another example, the model may further include models of the switch element 312 as well as the power source 302 and the capacitor 322, which may be part of the charger. Thus, the model could model the control sequence to the switch that generates the input pulses to the filter 324 and analyze the modeled charging waveform generated by the model. Various aspects of the present disclosure include the generation of carefully controlled charging waveforms that are not simply conventional constant current, constant voltage, or square wave edge pulsed charging signals, so that the system accurately reproduces the target or planned charging signal as the actual charging signal. Furthermore, the use of models is beneficial because in many charging environments, overly complex measurement and feedback systems are too expensive, energy intensive, slow, processor architecture area intensive, impractical and / or ineffective.

[0036] Nevertheless, particularly in the calibration sequence described below, the circuit controller 306, or more generally the processing unit 106, may wirelessly receive measurements of battery characteristics from the battery measurement circuitry 308 for use in confirming the model, modifying the model, and / or shaping the charging signal. Additionally, in some circumstances, the battery manufacturer may recommend or require monitoring of certain attributes of the battery, such as the open circuit voltage during charging. However, as described in more detail below, such feedback mechanisms may occur at rates that do not allow for effective shaping of the charging signal, or may be implemented in a manner that requires low-cost and simple feedback elements, such that the model may be utilized to determine the control signals 330 to control elements of the circuit 300 with or without the feedback mechanism. Feedback may also occur via wireless connections such as Bluetooth, Wi-Fi, etc. In some cases, a wireless charging (transformer) interface may be included, while a wired feedback port may be formed through a pin-socket, which may also be useful for aligning the inductors to create a repeatable transformer gap and orientation between each inductor.

[0037] As introduced, the circuit 300 may include one or more components that shape a charging signal for charging the battery 304. In the illustrated embodiment, the circuit 300 may include a switching element (e.g., a transistor 312) coupled to an output 334 of the power supply 302. The transistor 312 may receive an input signal, such as a pulse width modulated (PWM) control signal 330 that causes the transistor 312 to operate as a switching element or component. In general, the transistor 312 may be any type of transistor (e.g., a FET (or, more specifically, a MOSFET), a GaN FET, a silicon carbide-based FET, or any type of controllable switching element that controllably couples the first inductor 316 to the output 334 of the power supply 302). For example, the first transistor 312 may be a FET with a drain node coupled to the first inductor 316, a source coupled to the power supply 302, and a gate that receives the control signal 330 from the circuit controller. In various embodiments, the filter circuit 324 may also include various other possible inductive elements. For example, in the wireless embodiments discussed herein, the filter circuit may include a second inductor 318 that in combination with the first inductor forms a transformer, with each side or both sides of the transformer (e.g., primary and secondary) being considered inductive elements. The circuit controller 306 may provide a control signal 330 to control the operation of the transistor 312 as a switch that, when closed, connects the first inductor 316 to the power source 302 and allows current from the power source to flow through the first inductor 316. The inductance value, the time and frequency at which the transistor is operated, as well as other factors, may be adjusted to generate a waveform, particularly a waveform with controlled harmonics for the battery to charge the battery. With reference to the exemplary charging signal shown in FIG. 2, the signal at node 336 may be a pulse train around 0 volts to rail voltage (e.g., the voltage at node 334 provided by the power source 302).The pulses at node 336 may vary in duty cycle and may be generated at varying frequencies. However, collectively, the pulses are generated to provide a signal that is identical or nearly identical to the target charging signal. Thus, a signal such as that of FIG. 2 will be present at node 338 based on the combination of pulses present at node 336. Depending on the signal, pulses from 10 seconds to 1000 seconds (or more) may be generated to create the desired charging signal.

[0038] In addition to the first inductor 316, the circuit 300 may include other components, some of which are shown in FIG. 4. In particular, the circuit 400 may include a first capacitor 422 connected between the output of the power source 402 and ground. As will be discussed in more detail below, a portion of the energy required for the charging waveform may be provided by a combination of the power source and the capacitor 422. On the battery side of the system, on the battery side of the wireless gap 444 between the inductors, in the portion of the circuit referred to as the filter 424 as shown in FIG. 4, a second capacitor 420 may be connected between the second inductor 418 (at node 438) and ground. When placed in close proximity to the first inductor 416, the second inductor 418 transforms the charging signal generated in the first inductor by the pulse at node 436. The second inductor is coupled to the anode of the battery 404. Alternatively, the inductor 422 may be connected to the transformer inductor 418 by the capacitor 420, as also shown in FIG. The filter 424 of the circuit 400 may generally operate to prevent abrupt changes in the charging signal applied to the battery 404. In addition to converting pulses at the input of the filter to a charging signal, the filter may also filter any unintended high frequency noise from the battery. For example, when the first transistor 412 is closed based on the control signal 430, the first inductor 416, the second inductor 418, and the transformer formed when they are placed in close proximity may prevent abrupt increases in current sent to the battery 404. Such abrupt increases in current may damage the battery 404 or may be detrimental to the battery's lifespan. Additionally, the inductor 416 or inductors 418 and 422, alone or in combination with the capacitor 420, may shape the waveform applied to the battery, and the shaping of the waveform may be controllable by controlling the signal applied to the inductor 416.

[0039] In another example, the capacitor 422 may store energy from the power source 402 while the first transistor 412 is closed. When the first transistor 412 is opened in conjunction with closing the transistor 414, the capacitor 420 may provide a small amount of current to the battery 404 through the second inductor 418 to resist sudden drops in current to the battery, as well as be used to controllably shape the waveform applied to the battery to avoid particularly abrupt (high frequency) negative transitions. A filter circuit, which may include the inductor 422 and the capacitor 420 in FIG. 4, also filters out other unwanted signals, such as noise, which may include relatively high frequency noise. Other benefits for charging the battery 404 are also realized by the filter circuit 424, but are not discussed herein for brevity.

[0040] Of course, the charging circuit 300 or 400 may include more or fewer components. For example, one or more components of the filter circuit 324 (424) may be removed or modified as needed to filter the charging signal to the battery 304 (404). Many other types of components and / or configurations of components may also be included in or associated with the charging circuit 300 (400). Rather, this circuit is merely one example of a battery charging circuit, and the techniques described herein for shaping a charging signal by utilizing a circuit model to generate or determine a control signal may be applied to any number of battery charging circuits. Additionally, various additional combinations of inductors or capacitors may be provided in series or parallel with those shown, and several such examples are described below with respect to various alternative wireless charging configurations.

[0041] As mentioned above, the signal shaping generator of the circuit controller may control the shape of the charging signal based on the model and / or feedback measurements of the battery received from each battery measurement circuit. For example, referring to FIG. 3 or FIG. 4, or various options discussed with reference to FIG. 5, the battery measurement circuit may apply an initial charging signal to the battery and obtain one or more measurements of the battery, such as the current flowing into the battery or the voltage across the battery. These measurements may be provided to the signal shaping generator to determine an error between an expected measurement of the battery characteristic and the measured value at the battery. Based on the determined error, the signal shaping generator may adjust the shape of the charging signal to the battery by controlling the first and second transistors with a control signal. In other words, the signal shaping generator 310 may modify the charging signal sent to the battery 304 to generate the expected measured characteristic of the battery. The control signal may cause the signal shaping generator to maintain the shape of the charging signal as long as the feedback measurements are expected. However, if a difference between the expected measurement and the measured value is detected, the circuit controller may modify the shape of the charging signal to bring the battery's response into a range of expected values. Such a process may not occur, may occur at the start of charging or at various times during charging, may occur periodically or intermittently, or may occur in response to some change or some metric (e.g., change in terminal voltage, state of charge, temperature).

[0042] In some cases, feedback techniques used by a signal shaping generator to modify or shape the charging signal to a battery may have too much latency to effectively shape a charging signal that occurs at high speeds. For example, the charging signal may include pulses that occur at a particular frequency, which is often faster than the battery measurement circuitry can obtain battery characteristic measurements and / or the circuit controller can adjust the shape of the charging signal in response to the measured battery characteristics. As a result, a circuit controller that utilizes feedback measurements to adjust the shape of the charging signal is often unable to fine-tune the charging signal to optimize battery charging, especially for high frequency charging signals.

[0043] FIG. 4 is a schematic diagram illustrating an alternative circuit 400 for charging a battery 404 using a circuit model 440, according to one embodiment. Various aspects of FIG. 4 have already been introduced above. The circuit 400 of FIG. 4 is an alternative version of the charging circuit 300 described above with reference to FIG. 3 and may include similar components such as a power source 402, a transistor 412 or other type of electronic switch, a battery 404, and a circuit controller 406. Although not shown, a battery measurement configuration may also be included. As above, the transistor 412 may be controlled by a control or input signal 430 that causes the transistor to operate as a switch and alternately connects an inductor 416 to the output of the power source 402. A filter may be considered the inductor 416 and may include a capacitor 420 and / or a second inductor 422. In general, the transistor 412 may be any type of FET transistor or any type of controllable switch device. The circuit controller 406 may provide a control signal 430 to control the operation of the first transistor 412 as a switch that, when closed, connects the inductor 416 to the power source 402 and allows a charging signal from the power source to flow through both inductors due to the action of a transformer formed between the inductors 416 and 418.

[0044] In many applications, cost and complexity can be an issue, but these should be minimized or avoided if possible. The use of a model can avoid the need to monitor values ​​at discrete components and avoid more complicated feedback measurements and controls. In some cases, the circuit model may determine how to generate a specific target shaped charging waveform at the battery by modeling components external to the circuit controller, such as power supplies, transistors, inductors (especially when they form a transformer after placement in close proximity), and the battery itself.

[0045] The components included in the model may have variable attributes to determine the effect of the components on the applied charging signal, and the model may be adjusted by adjusting one or more variable attributes of the modeled components. For example, a model of an inductor, or more specifically, a transformer that two inductors form when the charger and the device are arranged to charge the device's battery, may include an inductance value and a series resistance value. The battery itself may be modeled with an inductor and a resistor arranged in series. Other modeled components (switches and / or batteries) may also include various attributes to improve the accuracy of the simulations performed on the modeled components. Furthermore, the attributes of the modeled components may be adjusted over time based on performance data, characterization sequences, or other feedback data from the circuit parts or based on calculations or characterization methods. For example, the charging signal of the circuit of FIG. 4 may be sampled at various times and fed back to the circuit controller, and the controller may compare the received charging signal to an expected charging signal. Based on the difference, the circuit controller may modify or adjust one or more attributes of the modeled components to improve the accuracy of the model. The adjustment of the model components may be repeated over a period of time to take into account parasitic effects on the components.

[0046] Figure 5 illustrates several different wireless charging topologies. Instead of illustrating all of the various components involved in generating a signal at the input side of the wireless interface, such as models, controllers, switches, etc., the illustrated charging topologies focus on various features of the wireless portion of the interface and other components not discussed above with reference to Figures 1-4. However, it is to be appreciated that the various attributes discussed with reference to Figures 1-4 may be involved in generating a charging signal using the wireless features highlighted in Figure 5, and similarly, features of the various embodiments of Figure 5 may be integrated alone or in various combinations with the embodiments shown in the preceding figures.

[0047] FIG. 5A illustrates the topology generally introduced with reference to FIG. 3. Here, a control signal 500, such as a pulse train, is provided to the input of an inductor 502 at the charger side 504 of the illustrated system. A first inductor forms a transformer 510 when placed in close proximity to a second inductor 506 (which may be a component of a device 508 that includes a battery to be charged). In various examples discussed herein, the first inductor may be referred to as the primary winding of the transformer and the second inductor may be referred to as the secondary winding of the transformer, although this terminology is used for convenience only, the primary / secondary relationship may be reversed, and these terms may not be applicable to all possible "transformer" configurations formed in various wireless charging embodiments.

[0048] As shown in FIG. 5A and also in FIG. 3, a diode 512 is present between the second inductor 508 and the battery 514. The diode prevents the battery from discharging on the secondary side of the transformer. In this example, the diode may be part of the model. The diode may also act as a half-wave rectifier. Thus, if the control pulse on the input side of the transformer contains a negative component, resulting in a negative charging signal component, the diode allows only positive current to flow and prevents the negative part of the signal from being applied to the battery.

[0049] FIG. 5B is another alternative wireless charger, again without showing some of the components of FIGS. 3 and 4. FIG. 5B includes the same primary inductor 502. However, on the secondary side (wireless charging system side 508) across the air gap 516, the secondary side of the formed transformer is comprised of a center-tapped secondary 518 (a tapped segmented inductor). The top half 520 of the inductor is connected to a first diode 522 and operates as in FIG. 5A. The bottom half 524 is connected to a second diode 526. The battery return 525 (connection to the battery negative terminal (or tab, etc.)) is connected to the center tap. The additional combination of the center-tapped secondary, return path, and second diode constitutes a full-wave rectifier. Now, rather than simply blocking the transmission of any portion of the signal 500 that could be negative, the second diode inverts any negative signal 500 to a positive signal.

[0050] Figure 5C is a wireless charging configuration having a primary side 502 and a secondary side 506 with a full bridge diode rectifier 528 placed across the secondary winding (inductor) 506 and a battery 514 connected to the bridge. The bridge inverts any negative portion of the charging signal developed across inductor 506, similar to the full wave rectifier configuration of Figure 5B.

[0051] With regard to modeling, in addition to modeling some combination of components in the wireless charging environment (e.g., transformers (e.g., one or more inductors of the charging device and one or more inductors of the device of the battery to be charged), switches (e.g., transistors or diodes)), the system may consider the air gap 516 that is formed between each inductor (transformer winding) when the battery device is placed in close proximity to the charging device. As described above, wireless charging of a battery requires that the device including the battery be placed in close proximity to the charging device so that the windings present on each device form a transformer. In some embodiments, there may be mechanical interlocks and / or positioning mechanisms that enforce repeatable placement of each component of the transformer in the same location and formation of repeatable air gaps so that the modeling aspects are consistent and not affected by air gap variability. In one example, the system may include a molded receptacle (or molded plug) on ​​the charger and a matching molded plug (or receptacle) on the device including the battery, such that the interconnection of the devices mechanically aligns the components of the transformer in a predictable manner with a consistent air gap. A molded plug may be formed into the body of the device that houses the battery. Other mechanical features may be used, such as keyed or molded pads with matching keys and shapes. In the example of a rechargeable watch, the back housing of the watch may include a defined shape or key feature that aligns with the receptacle of the charger.

[0052] However, in other possible implementations, the air gap may not be mechanically predictable due to random placement of the charging device relative to the charger, and the relative placement of the inductors may not be consistent, depending on geometry, among other things. In such cases, it may be advantageous to adapt the model to take into account such issues during any given charging cycle, which may be managed through a calibration process described below.

[0053] In various embodiments, it may also be desirable to achieve the functionality of one or more diodes without the losses of a conventional diode, alone or in combination with adjustments for air gap variability. Figures 5D-5G include wireless charger topologies that include, among other variations from the topologies shown in Figures 5A-5C, transistors in place of diodes and various possible wireless feedback paths for purposes of modeling, etc. Figure 4 also illustrates such a transistor 442. It is to be recognized that the various features of Figures 5D-5G, alone or in combination with other features discussed herein with respect to other figures, may form entirely new possible embodiments, and that various features of Figure 5 or other figures may or may not be included in any given embodiment.

[0054] Starting with FIG. 5D, the charger-side transformer winding (e.g., primary inductor) is a split winding 530. It is to be appreciated that the winding may be irregularly split, meaning that there may be more or less turns in each of the first and second portions 532 and 534 of the primary winding (as is possible with other split winding embodiments discussed herein). The device-side winding (e.g., secondary inductor winding 536) is also split or otherwise constitutes three different winding areas, which may be achieved by split or tapped windings, separate windings, or a combination thereof, and the number of turns in the three different portions may be different, as with other split winding configurations discussed herein. The first portion 532 of the charger-side winding is considered an inductor that constitutes a target charging signal through switchable control by pulses 531. The target charging signal is reproduced across the gap 516 of each first portion 538 of the device-side winding. The third section 540 of the device side winding is used to activate a switch 542 (e.g., a transistor) when a charging signal pulse is present on the first section 532 of the device side winding during charging. More specifically, the charging signal is positive and a portion of the charging signal is reproduced on the upper side 540 (third section) of the device side winding. When a charging signal within a range of possible values ​​is present, the number of turns can be adjusted so that the signal from the third secondary winding is sufficient to drive the switch 542. The switch is driven with very little loss across the transistor to pass the charging signal to the battery. The intrinsic diode of the transistor then blocks reverse current. In one example, the third section of the secondary winding has a relatively larger number of turns than the first section 538 of the secondary winding. In this way, the voltage level can be positive enough to turn on the switch even if the amount of charging current and therefore the pulse level in the primary side first winding and the secondary side first winding are relatively low at different points of the charging signal.

[0055] In various possible configurations, it may be useful for the charger to obtain information from the battery. The embodiment of FIG. 5D includes a separate transformer section including the lower second portion 534 of the primary winding, which may be a completely separate winding as described above, as opposed to the tap winding shown and the separate complementary lower (second) portion 544 of the secondary winding on the appliance side. Battery feedback measurements from the battery monitoring component 545 (which may obtain information as described above for FIG. 3 and FIG. 4) and other components may be transmitted asynchronously through a feedback transformer configuration formed from the second portion of the primary winding and the second portion of the secondary winding. Feedback may be used for modeling, verification, monitoring, and other functions discussed herein. Feedback may be by serial communication using a feedback inductor path, as is also possible in other embodiments discussed herein.

[0056] FIG. 5E shows another alternative embodiment of wireless charging. Here, the upper part of the secondary winding driving the switch may have the same configuration as shown in FIG. 5D. However, the feedback path is different and synchronous with the charging signal. Thus, there is only a first primary winding and no lower (second) part of the primary winding. In this example, feedback signals (e.g., battery measurement signals) are sent from the first secondary winding 538 to the primary winding 532. These signals are sent synchronously when the charging signal is zero (not on). As described herein, there may be periods when the charging signal is zero (e.g., rest periods of the charging signal or periods defined for the purpose of information transfer across the air gap). During such periods, the transformer may send current or stored battery data to the charger. The feedback path may be triggered, for example, by determining when a transistor is on or off, or may occur when a transistor is on or off. When the transformer is off, there is no charging signal, so the transformer formed by inductors 538 and 532 may cause the battery measurement circuitry to encode and transmit battery measurements to the charger.

[0057] FIG. 5F shows another alternative embodiment of wireless charging. In this embodiment, the feedback path is similar to FIG. 5D. However, here, the device 546 containing the battery to be charged activates the transistor 542. As shown, there is a control line 548 from the charging device (which may be a battery monitoring circuit) to the transistor gate. In this example, the battery side device may send a signal to the charger to start charging, which may use the same feedback path. At the same time, the charging device may activate a switch to pass the charging signal. During charging, the charger may send a signal through the feedback path to the charging device when appropriate to provide battery measurement data, and the charging device may then open the switch. In this example, a processing unit on the charging device side receives and transmits various signals and controls the transistor. This may be a separate processing unit from the battery measurement unit that monitors and collects data about the battery before, during, and / or after charging, or it may be the same processing unit as the battery measurement unit. In another example, the control line may be connected from the charger through a transformer to the transistor, such as the feedback path transformer of FIG. 5D.

[0058] Finally, FIG. 5G is another alternative wireless charging system. Here, there is only a single primary (inductor) 532 and secondary (inductor) 538 winding that, when deployed, operatively constitutes a transformer. A charging signal pulse generates a charging signal on the primary side. Also on the primary side, a control line 547 sends a signal across the windings to a communication port 549 of the battery unit that, when received, may activate a transistor 546 to pass the charging signal. Feedback from the battery measurement system may be sent asynchronously through the same transformer from the communication port. In such a situation, if no charging signal is detected, the transistor may be shut off and data may be sent across the transformer such that the system may first send a charging start signal prior to resuming the charging signal. The charging start signal may be a simple high voltage of some value or some binary sequence so that the battery unit may identify possible control signals. In some cases, initiation of charging is not necessary because sufficient battery measurement data is transmitted in any gaps (e.g., pause periods) between active charging portions of the charging signal such that feedback simply begins as soon as the charging signal is removed.

[0059] Also, although not shown, Bluetooth or some other wireless communication protocol may provide feedback and control signals depending on the environment in which the wireless charger is implemented and other factors.

[0060] FIG. 6 shows another example of a portion of a charging waveform. In the portion of the example shown, the charging waveform 600 at node 438 is superimposed with the charging waveform 610 at the input to the battery after further processing by the second inductor 422 on the battery side and coupled to the secondary inductor 418. Here, it can be seen that the charging waveform 600 at node 438 is a sinusoidal alternating signal that alternates around a nominal non-zero voltage 620 that rises from left to right. Thus, the control pulses at node 436 are an alternating pattern and a rising nominal non-zero voltage. The pulse width and frequency can be controlled to generate the pattern at node 438 after processing by the transistor. The alternating charging signal at node 438 is then further processed in the second inductor 422 to generate the charging waveform 610 that is applied to the battery. The alternating pattern remains present, but is substantially attenuated by the second inductor such that the amplitude is significantly smaller than at node 438, and the charging current is as intended. The nominal value of the AC pattern at node 438 after the transformer is essentially the charging signal remaining after the second inductor.

[0061] The controller 306 (406) uses the circuit model to generate the control signals for the switches to generate the desired charging waveform. In a charging sequence, the system may first calibrate the model. In one example, the model includes a mathematical model of an inductor in series with a resistor. At a simple level, the model may include an inductor representing the inductors 416 and 418 (which form an inductor model of a transformer). Note that the calibration may take into account variability in the air gap, variability in the placement of the primary and secondary windings, and other issues that may affect parts of the transformer model. In another option, the model may include one (or both) of the inductors 416, 418, and 422. Additionally, the model may include an inductance value of the battery to be charged. Similarly, the model may include resistance values ​​that account for various attributes of the filter circuit 324 (or filter circuit, if employed), including, for example, battery resistance and wiring resistance. In a model with inductance values ​​representing the inductance and resistance of the filter circuit transformer, the inductance and resistance values ​​may be adjustable or configurable.

[0062] Calibration involves generating a test signal (which may be a charging signal or a dedicated test signal) and determining whether the charging signal at the input to the battery matches the target signal. If the signals match, the model is deemed accurate and no adjustments are made to the model parameters. To determine the match, in one example, a calibrated test signal is applied to the battery. An example of such a test signal is shown in FIG. 7. The calibration signal has a first target current (IT1) and a second target current (IT2). In one example, the first and second target currents are intended to be identical, and the test signal has a flat top and a generally trapezoidal shape with a gradually rising leading edge and a gradually falling trailing edge, as shown. As described elsewhere, the target and measurements may be target voltages and voltage measurements. The measurement at time T1 is taken some time after the transition to the flat top so that the current level of the test signal stabilizes after the rising edge. Similarly, the second measurement is taken before the falling edge of the test signal so that the second current is measured before the signal begins to return to zero. The system evaluates the actual current at times T1 and T2, such as by a battery measurement circuit 308, which may also be present in the example of Figure 4 or various measurement circuits of Figure 5, and compares the actual current measurements at each time to first and second expected target currents at each time. Feedback is achieved by various techniques discussed herein, including the technique of Figure 5.

[0063] The purpose of the calibration is that the actual measurements at T1 and T2, whether voltage or current, match the target, which indicates that the model matches the actual circuit performance. As mentioned above, model calibration may also address variability in the wireless charging environment due to the arrangement of the primary and secondary windings to form a transformer. The calibration technique may adjust the inductance value of the model and / or the resistance value of the model. Although the actual measurements of the current at times T1 and T2 can be compared to the target current, in one example, a different technique is employed that is more computationally simple. That is, the system includes a comparator that determines if the current (or voltage) at time T1 is greater or less than the target current (or voltage) at time T1 and does the same for time T2 against the target current (or voltage) at time T2. If one value matches and the other does not, the system adjusts the inductance value. Similarly, if one value is greater than the target current and the other signal is less than the target current, the system also adjusts the inductance value. In either case, the difference indicates a test signal with a sloping top as opposed to a target flat top, with the sloping top indicating a mismatch in the inductance of the model. Conversely, if both measurements are either greater or less than their respective target values, this indicates a mismatch in the resistance of the model. In the example of testing and measuring with voltage, if the measured voltage is below the target, the resistance is decreased, and if the measured voltage is above the target, the resistance is increased. Of course, both inductance and resistance may require calibration. In one example, the system iteratively adjusts the model by repeatedly applying the test signal, adjusting the inductance and / or resistance, and measuring the current (or voltage) at both times T1 and T2 until the measurements at both times match the target. The model is considered calibrated when the measured voltage is within some percentage or threshold of the target (e.g., 0.01%, 0.1%, 1%, or some other tolerance depending on the accuracy specified or required for any particular implementation, application, etc.).

[0064] After calibrating the model, the system may begin charging. Alternatively, the system may further calibrate the model so that a pulse train at the filter input generates the target waveform. In some examples, the model also includes a switch that generates a pulse train at the filter input to generate the target charging waveform. The model is programmed to generate a target voltage and / or target current appropriate for the target waveform at any particular time. The pulse at 336 generates the target waveform after processing by the filter (with various possible combinations of the charging signal forming components discussed herein). In one example, such as generating the target waveform of FIG. 2, the target waveform has a well-defined start and end time, where the signal transitions from zero voltage (and / or zero current, depending on the measurement and / or control method) to a non-zero value of the target charging waveform. The same happens at the end time, where the voltage and / or current transitions from a non-zero value of the charging waveform to zero. It is also possible to have the charging current momentarily below zero between charging signals. In various possible examples, the discrete charging waveform is repeated several times, sufficient to account for and accommodate significant changes in the charging rate, until the system determines that some change in the charging control is necessary, which may be a change in the charging signal and / or a recalibration of the model. Nevertheless, the model may further calibrate itself by generating a target pulse train to a calibrated filter element of the model so that the desired target signal is generated by the model. This portion of the calibration may be performed by running the target signal through the model without measuring the actual circuit performance or the actual charging signal. The switch control may be adjusted in any number of ways to adjust the pulsing of the filter circuit to generate the target waveform. For example, the on-time of switch 312 may be adjusted to generate pulses of different widths, and the frequency of pulsing at 336 may also be adjusted.The width and frequency of the pulses required to generate the desired variety of charging signal shapes, as well as the value of the shape at a particular time, may be varied over an almost infinite number of combinations of pulses to generate an infinite number of possible charging signal shapes and patterns. Nevertheless, the system may generate the charging waveform by iterating the switch control until the modeled filter circuit generates the desired target charging waveform at the battery, and then initiating charging with the calibrated control and model.

[0065] It is to be appreciated that calibration does not occur at every charge cycle, but rather aspects of calibration may occur within a charge cycle (a charge cycle may be considered from the start of charging to the end of charging at 100% SOC or otherwise). For example, the inductance and / or resistance of the modeled filter circuit may change during or over many charge cycles due to various electrochemical and electrodynamic effects of the battery over time and cycling, heat, charging current value, and other reasons. Similarly, circuit elements may change due to heat and cycling, among other reasons. It is also to be appreciated that different elements of the filter circuit may have different effects on the accuracy of the modeled circuit's performance. For example, although capacitor 320 may be present in the filter, its value is not included in the model as it may not have a significant effect on the modeled performance. Similarly, other components outside of the filter circuit, such as the power supply, may be modeled. Similarly, capacitor 322 may be modeled.

[0066] In one example, as described above, the target waveform may be a repeated shaped charging signal, and the charging signal may have a zero state between the repeated shaped charging signals. The zero state may prevent any minute errors in the manufacturing of the filter circuit of the target shape from propagating to subsequent shapes. Furthermore, in the synchronous feedback scheme discussed with reference to FIG. 5, a wireless feedback signal of the battery measurement may be transmitted during the zero state. Also, a capacitor 322 is included so that the system has sufficient charging energy to generate the target shape. In some cases, if the power source alone is insufficient to generate the charging current and voltage at a particular point in the target charging waveform, the capacitor stores energy to meet that demand. Between the target charging signals, the capacitor can be recharged to have energy available for the next sequence. Given its role in the overall delivery of the charging signal, the capacitor 322 may also be modeled and taken into account during calibration, such as control signal calibration.

[0067] Nonetheless, once the model has been calibrated and / or the switch control and micro-pulsing of the filter circuitry has been calibrated, the system will begin charging.

[0068] Additionally, the charging circuits and methods described herein may be applied to batteries containing one or more cells. In a multiple cell configuration, the cells may be arranged in a series configuration, a parallel configuration, or a combination of series and parallel configurations. Multiple battery cells arranged in a series configuration can reduce the overall current used to charge the battery cells because the current is split between the series connected battery cells. By connecting the battery cells in series, the current required by the charging circuit can be reduced, further improving the efficiency of the charging circuit.

[0069] FIG. 8 is an alternative example of a wireless system 800 according to various aspects of the disclosure. In this example, a power source 800 (shown here as an AC source, but which may be from a typical wall outlet) is coupled to a wireless interface 804. The interface may include a pair of inductors or a pair of coils of a transformer formed in the interface, as discussed in other examples herein. In the example shown, one inductor or coil is coupled to the power source. Although various possible configurations are possible, in one example, the inductor or coil is disposed within a housing, and a power cord connects the coil to the power source. In the case of a wall outlet, signal conditioning such as voltage levels may be required in some configurations. Similarly, if the power source is DC, DC-AC conversion may be required to provide an AC signal to the inductor.

[0070] On the other side of the air gap 806 in the wireless interface 804 is a second inductor (e.g., the other coil of a transformer). In various possible configurations, the second inductor may be in a housing, which may be a battery pack, may be in electrical communication with a battery pack, or may be part of an apparatus that includes the battery 810 to be charged. The wireless interface may also include various types of possible power conversion electronics that convert the AC signal in the second inductor to a DC signal.

[0071] The system includes a processing unit 106 along with a model 112, a controller 108, and a charging signal shaping unit 110 as discussed herein in connection with various embodiments. Based on the control and shaping, a shaped charging waveform may be applied to the battery to charge the battery. The system may further include a battery measurement unit 812 that may provide back various possible parameters such as terminal voltage, charging current, and / or temperature to the unit 106 for various charging purposes.

[0072] FIG. 9 is yet another example of a wireless system 900 according to various aspects of the disclosure. Here, the power source 902 is DC and the transformer formed in the wireless interface requires some form of AC signal, so there is a DC-AC conversion 904 on the power source side of the system. The DC-AC converter, also referred to as an inverter in certain circumstances, can include many possible circuit configurations that convert the DC signal to an AC signal. As with other embodiments discussed herein, AC power is applied to an inductor 906 on one side of an air gap 908, and this AC power is transferred to a second inductor 910 if the two inductors are placed in close proximity to form a transformer. In this example, the power source, DC-AC converter, and first inductor are part of a single assembly, and the various elements may be housed in a single housing or may be interconnected through cables or the like.

[0073] The second inductor 910 is operatively connected to an AC-DC converter 912, which may be in the form of a rectifier or other AC-DC converter type. The DC signal from the converter is applied to a power rail 914. The rail may include a capacitor 916 to provide a more complete DC signal and may provide additional power to the rail as needed. A pair of switches 918 and 920 are coupled to the rail and controlled by the processing unit 106. A control pulse train from the switch at node 922 causes an inductor 924 to generate a shaped charge waveform that is applied to the battery 926. As with the other embodiments, the system may also include a battery measurement unit, which may be a discrete component coupled to the battery and provide battery and / or charge information back to the unit 106 to shape or control the charge.

[0074] In the examples of FIGS. 8 and 9, the model may be of an inductor (e.g., one or more inductors that make up the primary and secondary sides of a transformer formed in the wireless interface of FIG. 3) as opposed to one or more components of a transformer. As with other examples, the charging signal shaping algorithm may provide an expected or target charging signal for charging the battery. The model may be used to verify and / or adjust the control for generating the signal. The model may also output one or more control signals to components, such as switches, of the charging signal shaping circuit based on the target charging signal and modeling of the components of the charging signal shaping circuit. While in some cases an aspect of the shape of the shaped charging signal may correspond to a harmonic (or multiple harmonics) associated with optimal transfer of energy to the battery, the objective of the system, among other objectives, is to efficiently generate and apply a shaped charging signal (which may be any shape determined or prescribed by the system) to the battery. The prescribed and / or controlled shape may include the content of the charging signal or may be any shape prescribed by the control. The control signals to the components of the charging signal shaping circuitry may be based on models of the shaping circuitry components, including the wireless interface components, rather than being based strictly on feedback of measurements of the charging signal at the battery being charged, such as voltages and currents representative of the battery charging circuit, or of the battery itself. This approach is sometimes referred to as a "feed-forward" technique.

[0075] As introduced above, the charging system may use a model rather than an extensive feedback environment using detailed feedback of various signals and battery characteristics. In the example of FIG. 8 and FIG. 9, the model may be of an inductor and may include a resistor in series with the inductor, with a configurable inductance value representing, for example, the inductor 924. The model may include other modeled values ​​as well depending on the inductor and the battery to be charged as well as any components. Thus, the model may be an inductance value, which may be in series with a resistance value. In the presence of a controlled pulse train at the input of the model, the model can predict the charging signal output to the battery. Thus, for example, a pulse train at node 922 can generate a signal at the battery as shown in FIG. 2 or FIG. 6. In another example, the model may further include switch elements such as 918 and 902, as well as an AC-DC power converter (which may also include elements of a wireless interface and a power supply that provides power to the converter), and a capacitor 916. The model may thus model the control sequence to a switch that generates input pulses to a shaping inductor (e.g., inductor 924) (which may be considered a filter, whether part of a transformer or not, alone or in combination with other elements such as an operatively coupled capacitor or additional inductors as shown in various other examples) that receives the pulse train and forms a shaped charging waveform, and may be able to analyze the modeled charging waveform generated by the model. Because various aspects of the present disclosure include the generation of carefully controlled charging waveforms that are not traditional simple constant current, constant voltage, or square wave edge pulsed charging signals, accurate reproduction of the target or planned charging signal as the actual charging signal generated by the system is important. Furthermore, the use of a model is beneficial because in many charging environments, overly complex measurement and feedback systems are too expensive, energy intensive, slow, processor architecture area intensive, practical and / or effective.

[0076] With reference to FIG. 10, an exemplary computer system 1000 having one or more computing units capable of implementing the various systems and methods discussed herein is described in detail. The computer system 1000 may be part of a controller, may be in operative communication with the various embodiments discussed herein, may perform various operations related to the methods discussed herein, may process various data for characterizing a battery offline, or may be part of an overall system discussed herein. The computer system 1000 may process and / or provide various signals discussed herein. For example, such a computer system 1000 may be provided with battery measurement information. The computer system 1000 may also be applicable to, for example, the controllers, models, and regulation / shaping circuits discussed with respect to the various figures, and may be used to implement the various methods described herein. The specific implementation of these devices may be of various possible specific computer architectures, not all of which are specifically discussed herein, as would be understood by one of ordinary skill in the art. Further, it should be understood that the computer system may be considered and / or include an ASIC, FPGA, microcontroller, or other computer configuration, and various such possible implementations may include fewer or more components than those discussed below, and may have interconnections and other modifications, as will be appreciated by those skilled in the art.

[0077] The computer system 1000 may be a computer system capable of executing a computer program product to execute a computer process. The computer system 1000 receives data and program files, reads the files, and executes the programs therein. Some of the elements of the computer system 1000 are shown in FIG. 10, including one or more hardware processors 1002, one or more data storage devices 1004, one or more memory devices 1006, and / or one or more ports 1008-1012. The computer system 1000 may also include other elements that one of ordinary skill in the art will recognize, but which are not explicitly shown in FIG. 10 or otherwise discussed herein. The various elements of the computer system 1000 may communicate with each other by one or more communication buses, point-to-point communication paths, or other communication means not explicitly shown in FIG. 10. Similarly, in various embodiments, the various elements disclosed in this system may or may not be included in any given embodiment.

[0078] The processor 1002 may include, for example, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), and / or one or more internal cache levels. The presence of one or more processors 1002 may result in the processor 1002 comprising a central processing unit or multiple processing units that may execute instructions and perform operations in parallel with one another, generally referred to as a parallel processing environment.

[0079] In various possible combinations, the techniques described herein may be implemented at least in part in software stored in data storage device 1004, in software stored in memory device 1006, and / or in software communicated via one or more of ports 1008-1012, such that computer system 1000 of FIG. 10 is a dedicated machine for performing the operations described herein.

[0080] The one or more data storage devices 1004 may include non-volatile data storage devices capable of storing data generated or employed within the computer system 1000, such as computer-executable instructions for executing computer processes, which may include instructions for both application programs and an operating system (OS) that manages various components of the computer system 1000. Data storage devices 1004 may include, but are not limited to, magnetic disk drives, optical disk drives, solid-state drives (SSDs), flash drives, and the like. Data storage devices 1004 may include removable data storage media, non-removable data storage media, and / or external storage devices available via a wired or wireless network architecture to computer program products, such as one or more database management products, web server products, application server products, and / or other additional software components. Examples of removable data storage media include compact disc read-only memory (CD-ROM), digital versatile disc read-only memory (DVD-ROM), magneto-optical disks, flash drives, and the like. Examples of non-removable data storage media include internal magnetic hard disks, SSDs, and the like. The one or more memory devices 1006 may include volatile memory (e.g., dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and / or non-volatile memory (e.g., read-only memory (ROM), flash memory, etc.).

[0081] A computer program product including mechanisms for implementing the systems and methods of the techniques described herein may reside in data storage device 1004 and / or memory device 1006, which may be referred to as a machine-readable medium. It should be understood that a machine-readable medium may include any non-transitory tangible medium capable of storing or encoding instructions for performing any one or more of the operations of the present disclosure performed by a machine, or storing or encoding data structures and / or modules utilized by or associated with such instructions. A machine-readable medium may include one or more media (e.g., centralized or distributed databases and / or associated caches and servers) that store one or more executable instructions or data structures.

[0082] In some embodiments, computer system 1000 includes one or more ports, such as input / output (I / O) port 1008, communication port 1010, and subsystem port 1012, for communicating with other computer, network, or vehicle equipment. Ports 1008-1012 may be combined or separated, and computer system 1000 may include more or fewer ports. It is understood that I / O port 1008 may be connected to devices, such as I / O devices, that input information to or output information from computer system 1000. Such I / O devices may include, but are not limited to, one or more input devices, output devices, and / or environmental transducer devices.

[0083] In one embodiment, the input device converts human-generated signals, such as human voice, physical movements, physical touch or pressure, and / or the like, into electrical signals as input data to the computer system 1000 via the I / O port 1008. In some examples, such inputs may be different than the various systems and methods discussed with respect to the preceding figures. Similarly, the output device may convert electrical signals received from the computer system 1000 via the I / O port 1008 into signals that can be detected or used by the various methods and systems discussed herein. The input device may be an alphanumeric input device including alphanumeric or other keys for communicating information and / or command selections to the processor 1002 via the I / O port 1008.

[0084] The environmental transducer device converts one form of energy or signal into another for input to or output from the computer system 1000 via the I / O ports 1008. For example, an electrical signal generated within the computer system 1000 may be converted into another type of signal and / or vice versa. In one embodiment, the environmental transducer device senses characteristics or aspects of the environment local to the computer device 1000 or remote to the computer device 1000, such as battery voltage, open circuit battery voltage, charging current, battery temperature, light, sound, temperature, pressure, magnetic fields, electric fields, chemical properties, etc.

[0085] In one embodiment, the communication port 1010 may be connected to a network from which the computer system 1000 may receive network data useful in performing the methods and systems described herein, as well as transmitting information and network configuration changes it determines. For example, charging protocol updates, sharing battery measurement or computational data with external systems, etc. The communication port 1010 connects the computer system 1000 to one or more communication interface devices configured to transmit and / or receive information between the computer system 1000 and other devices over one or more wired or wireless communication networks or connections. Examples of such networks or connections include, but are not limited to, Universal Serial Bus (USB), Ethernet, Wi-Fi, Bluetooth, Near Field Communication (NFC), Long Term Evolution (LTE), etc. One or more such communication interface devices may be utilized to communicate with one or more other machines via communication port 1010, directly or via a point-to-point communication path, via a wide area network (WAN) (e.g., the Internet), via a local area network (LAN), via a cellular (e.g., third generation (3G), fourth generation (4G), fifth generation (5G)) network, or via another communication means.

[0086] Computer system 1000 may include a subsystem port 1012 for communicating with one or more systems associated with a device to be charged in accordance with the methods and systems described herein to control the operation of the device and / or exchange information between computer system 1000 and one or more subsystems of the device. Examples of such subsystems for a vehicle include, but are not limited to, motor controllers and systems, battery management systems, etc.

[0087] The system depicted in Figure 10 is only one possible example of a computer system that may employ or be configured in accordance with aspects of the present disclosure, and it should be understood that other non-transitory, tangible computer-readable storage media having computer-executable instructions stored thereon for implementing the techniques disclosed herein on a computer system may also be utilized.

[0088] The embodiments of the present disclosure include various steps described herein that may be performed by hardware components or embodied in machine-executable instructions, or may be used to execute the steps by a general-purpose or special-purpose processor programmed with these instructions, or may be performed by a combination of hardware, software, and / or firmware.

[0089] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of the present invention. For example, while the above-described embodiments (also referred to as implementations or examples) exhibit certain features, the scope of the present invention also includes embodiments including different combinations of features and embodiments that do not include all of the above features. Accordingly, the scope of the present invention is intended to include all such alternatives, modifications, and variations, together with their respective equivalents.

[0090] Although specific embodiments have been discussed, it should be understood that they are for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from the spirit and scope of the present disclosure. For this reason, the following description and drawings are illustrative and should not be construed as limiting in any way. Numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, in certain instances, well-known or conventional details are not set forth in order to avoid obscuring the description. References to "one embodiment" in this disclosure may be references to "the same embodiment" or "any embodiment." And such references mean at least one of the embodiments.

[0091] Reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the disclosure. The phrases "in one embodiment" or, similarly, "in one example" or "in one instance" appearing in various places in this specification do not necessarily all refer to the same embodiment or to separate or alternative embodiments that are mutually exclusive of other embodiments. Furthermore, various features are described that may be exhibited in some embodiments and not exhibited in other embodiments.

[0092] The terms used herein generally have their ordinary meaning in the art, in the context of this disclosure and in the particular context in which each term is used. Also, alternative expressions and synonyms may be used for any one or more of the terms discussed herein, and no special emphasis should be placed on the recitation or explanation of a term in this specification. In some cases, synonyms of a particular term are provided. The description of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification, including examples of terms discussed herein, is for illustrative purposes only and is not intended to further limit the scope and meaning of the disclosure or any exemplary term. Similarly, this disclosure is not limited to the various embodiments described herein.

[0093] Without intending to limit the scope of the present disclosure, examples of the instruments, devices, methods, and their respective related results according to the embodiments of the present disclosure are given below. It should be noted that for the convenience of the reader, the examples may use titles or subtitles, but this does not limit the scope of the present disclosure. Unless otherwise defined, technical and scientific terms used herein have the meanings that are commonly understood by those skilled in the art to which the present disclosure pertains. In the event of any discrepancy, the present specification, including definitions, shall prevail.

[0094] Additional features and advantages of the present disclosure will be set forth in the description which follows, and in part will be apparent from the description or may be learned by the practice of the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present disclosure will become more fully apparent from the following description and the appended claims, or may be learned by the practice of the principles described herein.

Claims

1. 1. A system for charging a battery, comprising: Switch, a transformer in operative communication with the switch; a processor in communication with the switch and in communication with a model of the transformer, the processor being configured to generate a shaped charging waveform in response to executing the model by controlling the switch through execution of instructions to generate a pulse train at the transformer to generate the shaped charging waveform; A system comprising:

2. 2. The system of claim 1, wherein the switch is operatively coupled to a power source, and the processor is further configured to execute the pulse train according to the model and adjust the pulse train to generate the shaped waveform.

3. 2. The system of claim 1, wherein the model includes a configurable inductance value and a configurable resistance value, the processor being further configured by executing instructions to apply a known signal to the transformer and obtain a first measurement result at a first point of the known signal and a second measurement result at a second point of the known signal, and calibrate the model by changing at least one of the configurable inductance value or the configurable resistance value if at least one of the first measurement result at the first point or the second measurement result at the second point does not match a first target measurement result at the first point or a second target measurement result at the second point, respectively.

4. 4. The system of claim 3, wherein the first measurement is a first current or a first voltage, the second measurement is a second current or a second voltage, the first target measurement is a first target current or a first target voltage, and the second target measurement is a second target current or a second target voltage.

5. The system of claim 1 , wherein the processor comprises a microcontroller.

6. The system of claim 1 , wherein the pulse train is on a primary winding of the transformer.

7. The system of claim 6 , wherein the switch is a transistor.

8. 8. The system of claim 7, further comprising a secondary winding of the transformer; and a battery operatively coupled to the secondary winding to receive the shaped charging waveform.

9. The system of claim 1 , wherein the model includes an inductance value representing a transformer.

10. The system of claim 9 , wherein the model further includes a resistance value representing the transformer.

11. 1. A system for charging a battery, comprising: a first switch that receives power via a wireless interface; a first inductor in operative communication with the first switch; a processor in communication with the first switch and in communication with a model including the first inductor, the processor being configured to generate a shaped charging waveform in response to executing the model to generate the shaped charging waveform by controlling the switch through execution of instructions to generate a pulse train in the first inductor; A system comprising:

12. 12. The system of claim 11, wherein the first inductor comprises a first side of the wireless interface and further comprising a second inductor comprising a second side of a wireless interface, the first inductor and the second inductor operatively configuring a transformer when positioned in relative proximity.

13. 12. The system of claim 11, wherein the wireless interface further includes a second inductor on a first side of the wireless interface, the second inductor forming a transformer when placed in proximity to a third inductor on a second side of the wireless interface.

14. 12. The system of claim 11, further comprising an AC-DC converter operatively coupled to the wireless interface to convert an AC signal from the wireless interface to a DC signal operatively applied to the first switch.

15. The system of claim 14 , wherein the wireless interface receives AC power from a power source.

16. The system of claim 14, wherein the wireless interface includes a DC-AC converter that receives power from a DC source and provides an AC signal to a transformer of the wireless interface.

17. 12. The system of claim 11, wherein the model includes configurable inductance values, and the processor is further configured, by executing instructions, to: apply a known signal to the first inductor and obtain a first measurement result of the known signal at a first point and a second measurement result of the known signal at a second point, and calibrate the model by modifying at least one of the configurable inductance values ​​if at least one of the first measurement result at the first point or the second measurement result at the second point does not match a first target measurement result at the first point or a second target measurement result at the second point, respectively.

18. 18. The system of claim 17, wherein the first measurement is a first current or a first voltage, the second measurement is a second current or a second voltage, the first target measurement is a first target current or a first target voltage, and the second target measurement is a second target current or a second target voltage.

19. The system of claim 11 , wherein the processor comprises a microcontroller.

20. The system of claim 11 , wherein the configurable inductance value represents the first inductor.

21. The system of claim 17 , wherein the model further comprises a configurable resistance value.

22. 20. The system of claim 17, wherein the configurable inductance value of the model represents a transformer of the wireless interface, the transformer including the first inductor.

23. The system of claim 11 , further comprising a second switch in electrical communication with the first switch at a common node in electrical communication with the first inductor.

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