EP4674029A1 - Parameter estimation for wireless charging - Google Patents

Abstract

The present disclosure relates to systems and methods for estimating one or more parameters associated with a converter to configure wireless charging settings for a wireless charging system. In some embodiments, a method includes: perturbing a first coil that is inductively coupled with a second coil; estimating one or more circuit parameters of a converter that comprises the first coil and the second coil based on the perturbing; and configuring one or more wireless charging settings of a wireless charging system based on the one or more circuit parameters, where the wireless charging system is configured to charge a battery pack of a vehicle based on wireless transfer of power between the first coil and the second coil.

Description

TSLA.765WO / P2622-1NWO PATENT PARAMETER ESTIMATION FOR WIRELESS CHARGING CROSS-REFERENCE TO PRIORITY APPLICATION [0001] This application claims priority to U.S. Provisional Patent Application No. 63/487,564, entitled “ACTIVE VEHICLE ADJUSTMENT FOR WIRELESS CHARGING,” filed on February 28, 2023, the technical disclosure of which is hereby incorporated by reference in its entirety and for all purposes. TECHNICAL FIELD [0002] The present disclosure relates to systems and methods for wireless charging. More particularly, embodiments of the present disclosure relate to wireless charging systems and mechanisms for charging a battery pack of a vehicle. BACKGROUND [0003] Wireless charging devices are usable to wirelessly charge a vehicle, such as an electric vehicle with a battery pack. A wireless charging device may cause power received from an external source, such as the grid, solar cell, and so on, to be wirelessly transmitted (e.g., via induction) to the electric vehicle. The wireless charging device may be positioned under the electric vehicle to charge the electric vehicle. [0004] Self-inductance of transformer coils used in wireless charging applications can have large variations caused by environmental factors such as charging pad positioning (e.g., with respect to the vehicle) and/or nearby ferrous objects. The result of this variation poses technical challenges to stationary power converters in wireless charging systems, where a transformer inductance and impedance of a resonant tank are generally constant. SUMMARY [0005] The systems, methods and devices of this disclosure each have several innovative embodiments, no single one of which is solely responsible for all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. [0006] In some aspects, the techniques described herein relate to a wireless charging system including: a first coil; and a charging configuration determination module configured to execute a charging configuration determination procedure, the charging configuration determination procedure including: perturbing the first coil, wherein the first coil is inductively coupled with a second coil; estimating one or more circuit parameters of a converter that includes the first coil and the second coil based on the perturbing; and configuring one or more wireless charging settings of the wireless charging system based on the one or more circuit parameters, wherein the wireless charging system is configured to charge a battery pack of a vehicle based on wireless transfer of power between the first coil and the second coil. [0007] In some aspects, the techniques described herein relate to a wireless charging system, wherein the first coil is in a ground pad, and wherein the second coil is in a vehicle pad attached to the vehicle. [0008] In some aspects, the techniques described herein relate to a wireless charging system, wherein perturbing the first coil includes: shorting the second coil; applying sequentially in time a plurality of signal waveforms to the first coil, wherein each of the plurality of signal waveforms is generated based on a frequency of a plurality of frequencies; measuring a peak current through the first coil when each of the plurality of signal waveforms is applied to the first coil; and selecting one of the plurality of frequencies that corresponds to a minimum peak current through the first coil as a self-resonance frequency of the second coil. [0009] In some aspects, the techniques described herein relate to a wireless charging system, wherein perturbing the first coil includes: applying a signal waveform generated based on the self-resonance frequency of the second coil to the first coil; and measuring a peak current through the second coil to obtain a peak steady state current when the signal waveform is applied to the first coil. [0010] In some aspects, the techniques described herein relate to a wireless charging system, wherein estimating the one or more circuit parameters is further based on the peak steady state current. [0011] In some aspects, the techniques described herein relate to a wireless charging system, wherein the charging configuration determination procedure further includes perturbing the second coil. [0012] In some aspects, the techniques described herein relate to a wireless charging system, wherein perturbing the first coil and perturbing the second coil are performed non-overlapping in time. [0013] In some aspects, the techniques described herein relate to a wireless charging system, wherein the one or more circuit parameters include one or more of a self- inductance of the first coil, a self-inductance of the second coil, a reactance associated with the first coil, a coupling coefficient associated with the first coil and the second coil, or a turns ratio associated with the converter. [0014] In some aspects, the techniques described herein relate to a wireless charging system, wherein the one or more circuit parameters include a self-inductance of the first coil and a self-inductance of the second coil. [0015] In some aspects, the techniques described herein relate to a wireless charging system, wherein the one or more circuit parameters include a coupling coefficient associated with the first coil and the second coil. [0016] In some aspects, the techniques described herein relate to a wireless charging system, wherein the one or more wireless charging settings includes one or more of an operating frequency of the converter, a power limit for the wireless charging system, or a DC voltage level applied at a ground pad of the wireless charging system. [0017] In some aspects, the techniques described herein relate to a wireless charging system, wherein the charging configuration determination procedure is performed at a beginning of a wireless charging sequence. [0018] In some aspects, the techniques described herein relate to a wireless charging system, wherein the charging configuration determination procedure further includes charging the battery pack of the vehicle according to the one or more wireless charging settings. [0019] In some aspects, the techniques described herein relate to a wireless charging system, wherein the charging configuration determination procedure further includes causing an air suspension system of the vehicle to lower a vehicle body of the vehicle. [0020] In some aspects, the techniques described herein relate to a method of wireless charging, the method including: perturbing a first coil, wherein the first coil is inductively coupled with a second coil; estimating one or more circuit parameters of a converter that includes the first coil and the second coil based on the perturbing; and configuring one or more wireless charging settings of a wireless charging system based on the one or more circuit parameters, wherein the wireless charging system is configured to charge a battery pack of a vehicle based on wireless transfer of power between the first coil and the second coil. [0021] In some aspects, the techniques described herein relate to a method, further including wirelessly charging the battery pack of the vehicle according to the one or more wireless charging settings. [0022] In some aspects, the techniques described herein relate to a method of wireless charging, the method including: perturbing a first coil of a converter of a wireless charging system; estimating a self-resonance frequency of a second coil of the converter of the wireless charging system based on the perturbing the first coil; estimating a self-resonance frequency of the first coil based on the second coil being perturbed; calculating, based at least on the self-resonance frequency of the first coil and the self-resonance frequency of the second coil, one or more parameters associated with the converter; and setting one or more wireless charging settings for the wireless charging system based at least on the one or more parameters associated with the converter. [0023] In some aspects, the techniques described herein relate to a method, wherein perturbing the first coil to estimate the self-resonance frequency of the second coil includes: shorting the second coil; applying sequentially in time a plurality of signal waveforms to the first coil, wherein each of the plurality of signal waveforms is generated based on a frequency of a plurality of frequencies; measuring a peak current through the first coil when each of the plurality of signal waveforms is applied to the first coil; and selecting one of the plurality of frequencies that corresponds to a minimum peak current through the first coil as the self- resonance frequency of the second coil. [0024] In some aspects, the techniques described herein relate to a method, wherein perturbing the first coil to estimate the self-resonance frequency of the second coil includes: applying a signal waveform generated based on the self-resonance frequency of the second coil to the first coil; and measuring a peak current through the second coil to obtain a peak steady state current when the signal waveform is applied to the first coil. [0025] In some aspects, the techniques described herein relate to a method, wherein calculating the one or more parameters is further based on the peak steady state current. [0026] In some aspects, the techniques described herein relate to a method, wherein perturbing the first coil is performed before or after in time the second coil being perturbed. [0027] In some aspects, the techniques described herein relate to a method, further including charging a battery pack of a vehicle using the one or more wireless charging settings. BRIEF DESCRIPTION OF THE DRAWINGS [0028] Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. The drawings are provided to illustrate examples of the subject matter described herein and not to limit the scope thereof. [0029] Embodiments of the present disclosure are described with reference to the accompanying drawings, in which like reference characters reference like elements, and wherein: [0030] FIG. 1A illustrates an example wireless charging environment in which embodiments of the present disclosure can be implemented. [0031] FIG. 1B is a block diagram illustrating the example wireless charging environment of FIG.1A in accordance with embodiments of the present disclosure. [0032] FIG.2 is a block diagram illustrating at least a portion of a wireless charging system in accordance with embodiments of the present disclosure. [0033] FIG.3A illustrates an example block diagram of a wireless charging system in accordance with embodiments of the present disclosure. [0034] FIG. 3B illustrates an example circuit model modeling at least a portion of a converter of the wireless charging system of FIG.3A in accordance with embodiments of the present disclosure. [0035] FIG. 3C illustrates an example circuit model modeling at least a portion of a converter of the wireless charging system of FIG.3A in accordance with embodiments of the present disclosure. [0036] FIG. 4 illustrates an example process for estimating and/or calculating parameters associated with the example circuit model of FIG.3B and FIG.3C. [0037] FIG. 5A illustrates an example circuit topology of a converter, such as the converter of FIG.3A, in accordance with embodiments of the present disclosure. [0038] FIG.5B illustrates an example circuit model of the example circuit topology of FIG.5A. [0039] FIG. 6 illustrates an example process for estimating and/or calculating parameters associated with the example circuit model of FIG.5B. DETAILED DESCRIPTION [0040] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals and/or terms can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings. The headings are provided for convenience only and do not impact the scope or meaning of the claims. [0041] Generally described, one or more aspects of the present disclosure relate to systems and methods that adapt to variations associated with environments and/or components utilized for wireless charging. More specifically, some embodiments of the present disclosure disclose an estimation flow for estimating and/or calculating parameters associated with resonant converters or transformers. These parameters can be used to adjust settings of a wireless charging system accordingly to address technical challenges associated with inductance variations caused by environments around a wireless charger. Advantageously, the estimation flow enables a wireless charging system to operate more efficiently and/or safely in the presence of inductance variations. [0042] A wireless charging device can be usable to wirelessly charge a vehicle, such as an electric vehicle with a battery pack. The wireless charging device may cause power from an external source, such as the grid, solar cell, and so on, to be wirelessly transmitted (e.g., via induction) to the electric vehicle. The wireless changing device may also cause power from the electric vehicle to be wirelessly transmitted (e.g., via induction) to the grid. In some embodiments, the wireless charging device may be positioned under a vehicle. For example, the vehicle may drive over the wireless charging device. [0043] Self-inductance of transformer coils used in wireless charging applications can have relatively large variations caused by environmental factors, such as charging pad positioning (e.g., with respect to the vehicle) and/or nearby ferrous objects. The result of this variation poses a technical challenge that is new from the perspective of traditional stationary direct current to direct current (DC/DC) resonant converters in wireless charging systems, where the transformer inductance is constant and, therefore, impedance of the resonant tank is constant. Due to the relatively large variation of resonant tank inductance, it can be advantageous for a wireless charging system to adapt to (e.g., through firmware control) the changing inductance to achieve desirable operation of the wireless charging system and the desired power output. [0044] To address at least a portion of the above identified technical problems, some aspects of the disclosed technology perform, or otherwise enable, a parameter estimation sequence to estimate and calculate variables and/or parameters of an equivalent circuit model associated with a resonant converter employed by a wireless charging system. Using electrical signal sources, the coupling coefficient estimation sequence can perturb coils of a converter using various signal waveforms, estimate self-resonant frequency of each coil and/or one or more other variables associated with the equivalent circuit model, and calculate self-inductance of each coil based on estimated variables (e.g., self-resonant frequency of each coil). Based on self-inductance of each coil and/or one or more other calculated parameters (e.g., one or more of turns ratio, coupling coefficient, etc.), the wireless charging system may adjust settings and/or configurations (e.g., operating frequency of the converter, a power limit for the wireless charging system, or a direct current (DC) voltage level applied at a ground pad of the wireless charging system) for wireless charging. The one or more parameters can be determined prior to each wireless charging session in certain applications. [0045] In some embodiments, a disclosed wireless charging system may include a converter and a charging configuration determination module. The converter may include a ground pad coil and a vehicle pad coil. The ground pad coil may be deployed in a ground pad of the wireless charging system. The vehicle pad coil may be deployed in a vehicle pad that is attached or otherwise integrated into a vehicle to be charged. The charging configuration determination module may execute a charging configuration determination procedure that includes a coupling coefficient estimation sequence to at least calculate self-inductance of the ground pad coil and the vehicle pad coil. Based on the calculated self-inductance and/or one or more other parameters (e.g., turns ratio, coupling coefficient, series reactance, or the like) associated with the converter, the charging configuration determination procedure may further update or adjust charging settings or configurations of the wireless charging system. [0046] In some embodiments, the charging configuration determination procedure may include perturbing a ground pad coil to estimate a self-resonance frequency of a vehicle pad coil; perturbing the vehicle pad coil to estimate a self-resonance frequency of the ground pad coil; calculating, based at least on the self-resonance frequency of the ground pad coil and/or the self-resonance frequency of the vehicle pad coil, a set of parameters associated with a circuit model that models a converter; and configuring one or more wireless charging settings for a wireless charging system based at least on the set of parameters associated with the circuit model. [0047] In some embodiments, perturbing the ground pad coil to estimate the self- resonance frequency of the vehicle pad coil may include shorting the vehicle pad coil and performing a frequency sweep (e.g., injecting various electrical signals having various signal frequencies) of signals over a frequency range on the ground pad coil. More specifically, a plurality of signal waveforms may be applied to the ground pad coil sequentially and non- overlapping in time while the vehicle pad coil is shorted throughout the application of the plurality of signal waveforms. Each of the plurality of signal waveforms may correspond to a distinct signal frequency. During application of each of the plurality of signal waveforms, a peak current through the ground pad coil may be measured. A signal waveform that results in the smallest peak current can be identified. A signal frequency of the signal waveform can be selected as the self-resonance frequency of the vehicle pad coil. [0048] For example, assume N (e.g., a positive integer greater than or equal to two) signal waveforms are applied on the ground pad coil while the vehicle pad coil is shorted. A first signal waveform (e.g., a square waveform, a triangle waveform, or any other suitable type of signal waveform having certain voltage amplitudes) may have a first signal frequency (e.g., 50 kilohertz (kHz)), a second signal waveform may have a second signal frequency (e.g., 55 kHz), and a N^th signal waveform may have a N^th signal frequency. The first signal waveform may be applied to the ground pad coil for a particular time period (e.g., 3 milliseconds (ms)). During the particular time period when the first signal waveform is applied, the wireless charging system may measure a first peak current through the ground pad coil. After a waiting period (e.g., 1 ms), the second signal waveform may be applied to the ground pad coil for the particular time period. During the particular time period when the second signal waveform is applied, the wireless charging system may measure a second peak current through the ground pad coil. The above waveform application and peak current measurement process may be continued until the N^th signal waveforms are applied to the ground pad coil, and the N^th peak current through the ground pad coil is measured. The wireless charging system may select a signal frequency of a signal waveform that results in the smallest peak current as the self- resonance frequency of the vehicle pad coil. For example, if the second peak current measured during the application of the second signal waveform is smaller than all the other peak currents, the second signal frequency may be selected as the self-resonance frequency of the vehicle pad coil. [0049] In some embodiments, perturbing the vehicle pad coil to estimate a self- resonance frequency of the ground pad coil may be performed similarly to perturbing the ground pad coil to estimate the self-resonance frequency of the vehicle pad coil in accordance with any suitable principles and advantages described above, except the ground pad coil is shorted and signal waveforms been applied to the vehicle pad coil. By perturbing the vehicle pad coil, the self-resonance frequency of the ground pad may be estimated. In some embodiments, perturbing the ground pad coil may be performed sequentially with (e.g., before or after) perturbing the vehicle pad coil. Perturbing the ground pad coil may not overlap in time with perturbing the vehicle pad coil. [0050] Based at least on the self-resonance frequency of the ground pad coil and the self-resonance frequency of the vehicle pad coil, the wireless charging system (e.g., the charging configuration determination module) may calculate the set of parameters (e.g., a self- inductance of the ground pad coil, a self-inductance of the vehicle pad coil, a turns ratio associated with the converter, a coupling coefficient, a series reactance, or the like) associated with the circuit model that models the converter. Based at least on the set of parameters associated with the circuit model, the wireless charging system may configure or set one or more wireless charging settings (e.g., operating frequency of the converter, a power limit for the wireless charging system, or a DC voltage level applied at a ground pad of the wireless charging system) to accomplish desirable operations of charging. For example, if the self- inductance of the ground pad coil deviates upward due to variations caused by environmental conditions (e.g., because of nearby ferrous objects), the wireless charging system may reduce the DC voltage level applied at the ground pad for charging. The one or more wireless charging settings can be set by any suitable circuitry and/or processor(s) of the wireless charging system. For instance, one or more processors can direct the system to operate with any of the wireless charging settings disclosed herein. [0051] In some embodiments, to adjust or enhance inductive coupling between a ground pad coil and a vehicle pad coil, the wireless charging system may generate a control signal to cause a vehicle body to be lowered closer to the ground pad. For example, the wireless charging system may generate the control signal to cause an air suspension system of a vehicle to reduce a distance between the vehicle and the wireless charger such that the vehicle pad coil can be closer to the ground pad coil. Such a reduced distance can increase a coupling coefficient for wireless charging. The air suspension can bring the vehicle pad and the ground pad as close as possible to each other in certain applications. The air suspension can bring the vehicle pad coil closer to the ground pad coil prior to wireless charging. [0052] Although the various aspects will be described in accordance with illustrative embodiments and combination of features, one skilled in the relevant art will appreciate that the examples and combination of features are illustrative in nature and should not necessarily be construed as limiting. More specifically, aspects of the present application may be applicable with various types of wireless charging systems and devices under different contexts. Still further, although specific architectures of circuitry block diagrams or flow for estimating coupling coefficients and parameters associated with converters will be described, such illustrative circuitry block diagrams or state machine or architecture should not necessarily be construed as limiting. Accordingly, one skilled in the relevant field of technology will appreciate that the aspects of the present application are not necessarily limited to application to any particular types of converters or wireless charging infrastructures. Overview of Wireless Charging [0053] Generally described, inductive charging, commonly referred to as wireless charging, is a type of wireless power transfer. Inductive charging uses electromagnetic induction to generate, or otherwise provide, electricity to devices without requiring physical electrical connectivity. Specifically, various devices can be placed near a charging station or inductive pad without needing to be precisely aligned or make electrical contact, a physical dock, electric plug and the like. Such devices include, but are not limited, vehicles, manufacturing equipment, consumer electronics, medical devices, and the like. [0054] In accordance with aspects of the present application, inductive charging systems are configured to transfer energy through inductive coupling between components. An illustrative charging system includes a transferring component, which may be configured as a charging station or charging pad. An alternating current (e.g., an input current) from a power source passes through an induction coil in the charging station or pad. Based on the input current, the moving electric charge through the induction coil (e.g., a sender coil) creates (or elicits) a magnetic field. Illustratively, the strength of a magnetic field may fluctuate, at least in part, on changes or fluctuations in the input electric current's amplitude. The changing magnetic field creates an alternating electric current in an induction coil on a receiving device (e.g., a receiver coil). The induced alternating current in the receiving device can then pass through a rectifier, converting the induced alternating current to direct current. Finally, the receiving vehicle can include additional charging components and/or systems that utilize the converted direct current to charge battery systems, provide operating power, or a combination thereof. [0055] Greater distances between sender and receiver coils can be achieved when illustrative inductive charging systems use resonant inductive coupling components/techniques. More specifically, in some embodiments, a capacitor can be connected to each induction coil to create two LC circuits with a specific resonance frequency. The frequency of the alternating current is matched with the resonance frequency. Additionally, the matched frequency can be further chosen depending on a distance between the sending device and the receiver device with consideration for peak efficiency. Still further, use of other materials for the receiver coil such as silver-plated copper or sometimes aluminum to minimize weight and decrease resistance can be utilized for purposes of energy transfer efficiencies. [0056] FIG.1A is a diagram illustrative of an environment 100 for implementing an induction-based wireless charging system in accordance with various aspects of the present application. The environment 100 illustratively can correspond to commercial implementations, such as parking lots, parking stalls, charging booths, and the like. The environment 100 can correspond to private or other non-commercial implementations, such as private residences, etc. By way of an illustrative example, an implementation of an induction-based wireless charging system in a non-commercial implementation can include a sender component 102 that is configured to generate variable magnetic fields in accordance with an induction charging methodology. As also illustrated in FIG. 1A, the sender component 102, which can also be referred to as a transmitting component, can correspond to a stand-alone component that may be operable to be mounted or placed on a floor 104 or other planar surface. In other embodiments, the sender component 102 can be integrated or combined with other devices or components. [0057] The sender component 102 may be connected to a one or more power sources, such as an input from a utility company, real-time power sources (e.g., solar cells or wind energy sources), stored energy cells, or a combination thereof. The power sources are configured to provider the input alternating current as described herein. The sender component 102 may be connected via direct electric connection 106 to the power source, such as via a junction box 108 located on a wall surface 118. [0058] As illustrated in FIG.1A, in one embodiment, the sender component 102 corresponds to a form factor that allows for the location on the floor 104 for wirelessly charging with a vehicle having a receiver coil. The sender component 102 may have a form factor such that the vehicle may be located directly above a top surface of the sender component. Illustratively, the dimensions of the sender component 102 (e.g., the height and width of the sender component 102) may be configured so that a distance between the top surface of the sender component 102 and a bottom surface of the vehicle meets specific criteria, such as minimum distance between the sender coil and receiver coil, maximum distance between the sender coil and the receiver coil, or the like. In some embodiments, the vehicle or sender component 102 (or combination) may be configured with additional components for dynamically adjusting such distance or otherwise changing the relative orientation between the sender component 102 and the vehicle. In some embodiments, the sender component 102 can be configured to charge a battery pack of a vehicle, wherein the battery pack can have a nominal voltage of over 200 Volts (e.g., a nominal voltage of about 350 Volts or 355 Volts) and a maximum voltage of 400 Volts. In some embodiments, the sender component 102 can be configured to supply 800 Volts of direct current power. In some embodiments, the sender component 102 can supply a voltage in a range from about 200 Volts to 800 Volts. [0059] FIG.1B illustrates a block diagram of the environment 100 including a wireless charging device 111 (e.g., the sender component 102) in wireless communication with a vehicle 112, such as via induction-based magnetic fields. The wireless charging device 111 is further connected to one or more energy sources 110. Although the wireless charging device 111 is illustrated with a direct connection to the energy sources 110, at least some portion of the input alternating currently could also be provided via a wireless transmission method. Additionally, in embodiments with multiple power sources, the environment may also include various switching components to cause the selection of energy from individual energy sources 110 or a combination of energy sources 110. [0060] FIG.2 illustrates a block diagram of a sender component 102 that may function as a wireless charging device 111 (shown in FIG.1B). The sender component 102 can include at least a sender coil component 202 for causing the generation of magnetic fields from an input current provided from an energy source 110. As illustrated in FIG.2, the input current can be provided by a direct electric connection 106. [0061] In some embodiments, the sender component 102 can also include various sensor components 204 related to the charging process. By way of illustration, the sensor components 204A, 204B, 204C, and 204 can be configured for various functions, such as detection of vehicle 112, detection of objects, measurement of distances to the vehicle, environmental sensors (e.g., temperature sensors, moisture sensors), pressure sensors, and the like. In an embodiment, the sensor components 204 can include radar sensors. The sensor components 204 can include logic and processing components related to the charging process including operational measurements, operational control, safety measurements, communication components and the like. Example Wireless Charging System [0062] FIG. 3A illustrates an example wireless charging system 300 that is operable to estimate and calculate parameters associated with a resonant converter and/or a transformer. The wireless charging system 300 can adjust to respond to inductance variations caused by environments. The environments described in FIGS.1A, 1B, and 2 can be implemented in accordance with any suitable principles and advantages of the wireless charging system 300 and may utilize the same or similar architecture as described in FIG.3A. [0063] As shown in FIG. 3A, the wireless charging system 300 includes energy source(s) 110, a converter 310 (e.g., a DC/DC converter) that includes a ground pad 302 and a vehicle pad 304, and a charging configuration determination module 306. The ground pad 302 may be a part of the sender component 102. The vehicle pad 304 may be attached to or a part of the vehicle 112. The wireless charging system 300 is represented in a simplified, logical form and one or more additional components that may be implemented for wireless charging functionality. Further, some of the components separately illustrated therein may be physically integrated together. For example, some of the components (e.g., a portion of the converter 310 such as the ground pad 302 that includes a ground pad coil) may be deployed outside a vehicle (e.g., on a ground), and some of the components (e.g., another portion of the converter 310 such as the vehicle pad 304 that includes a vehicle pad coil) may be deployed within a vehicle. As such, in some embodiments, the ground pad 302 may be integrated as a part of the sender component 102 of FIG. 1A and the vehicle pad 304 may be integrated as a part of the vehicle 112 of FIG.1B. [0064] In some embodiments, the wireless charging system 300 of FIG.3A is used to charge a battery pack (that may be installed on the vehicle 112 of FIG.1B) through the operation of the converter 310 that converts electric power from the energy source(s) 110 to a voltage level suitable for charging the battery. In some embodiments, the ground pad 302 is wired connected and provided with electric power from the energy source(s) 110. [0065] In some embodiments, the charging configuration determination module 306 may execute a charging configuration determination procedure to at least estimate and calculate self-inductance of a ground pad coil in the ground pad 302 and a vehicle pad coil in the vehicle pad 304. Based on the calculated self-inductance and/or other parameters (e.g., turns ratio, coupling coefficient, series reactance, or the like) associated with the converter 310, the charging configuration determination procedure may further update or adjust charging settings or configurations of the wireless charging system 300 to achieve safe and power efficient wireless charging operations. The charging configuration determination module 306 can cause the wireless charging system 300 to perform operations related to measurements and/or calculations for determining one or more parameters of the of the converter 310. The charging configuration determination module 306 can be implemented by any suitable circuitry, such as dedicated circuitry, circuitry configured to execute specific instructions, or any suitable combination thereof. One or more processors executing specific instructions can implement some or all of the charging configuration determination module 306. Example Circuit Model [0066] FIG. 3B illustrates an example circuit model 300B that models at least a portion of a converter, such as the converter 310, in accordance with some embodiments of the present disclosure. As shown in FIG.3B, the circuit model 300B represents an LLC converter topology and thus may be represented by example parameters which, as an example, may relate to impedance Za, Zb, and Zc. In some embodiments, reactance Xa, Xb, and Xc (not illustrated in FIG. 3B) that are associated with Za, Zb, and Zc may be determined using an estimation process that will be illustrated with reference to FIG.4. [0067] As noted above, the estimation process may include applying a perturbation (e.g., varying electrical signal waveforms generated by the charging configuration determination module 306) to a converter and measure responses to calculate parameters (e.g., Xa, Xb, and Xc) associated with the circuit model 300B. [0068] FIG. 3C illustrates an example circuit model 300C that models at least a portion of a converter, such as the converter 310, in accordance with some embodiments of the present disclosure. As shown in FIG. 3C, the circuit model 300C includes a ground pad coil 312 and a vehicle pad coil 314. The ground pad coil 312 is deployed in the ground pad 302, and the vehicle pad coil 314 is deployed in the vehicle pad 304. The ground pad coil 312 has a self-inductance L1, and the vehicle pad coil 314 has a self-inductance L2. As noted above, the self-inductance L1 and the self-inductance L2 may vary due to, for example, varying environmental conditions, such as ground pad 302 positioning (e.g., with respect to the vehicle pad 304) and/or nearby ferrous objects. Additionally, the turns ratio n and/or other parameters (not shown in FIG. 3C) associated with the circuit model 300C may also vary due to environmental conditions. [0069] As noted above, in some embodiments, the charging configuration determination module 306 may execute a charging configuration determination procedure to at least determine one or more of the self-inductance L1, the self-inductance L2, the turns ratio n, or one or more other parameters associated with the circuit model 300C. [0070] In some embodiments, based on equations that will be described below, an example order for estimating parameters associated with the circuit model 300B and/or the circuit model 300C includes determining the self-inductance L2 of the vehicle pad 304 (e.g., the charging coils on the vehicle) followed by the self-inductance L1 of the ground pad coil 312. The turns ratio n may then be determined using these self-inductances L2 and L1. Subsequently, the series reactance (e.g., Xa) may be determined based on the turns ratio n. A coupling coefficient k and/or other parameters (e.g., Xb and Xc) may also be determined. Circuit Parameters Estimation Process [0071] FIG. 4 illustrates an example process 400 for estimating and/or calculating parameters and/or variables associated with the example circuit model of the converter 310. The process 400 can involve a parameter estimation sequence that may be a portion of a charging configuration determination procedure. The parameter estimation sequence can be performed at a beginning of each charging session. In some embodiments, the example process 400 may be implemented and/or directed by the charging configuration determination module 306 to determine parameters and/or variables associated with the circuit model that models the converter 310. As shown in FIG.4, the process 400 may include two phases, including a phase 402 and a phase 404. Although the phase 402 is illustrated to be performed before the phase 404, the phase 404 may be performed before the phase 402 in other embodiments. It should also be noted that the temporal durations (e.g., 3 ms, 1 ms, 100 ms, 500 ms, or the like) shown in FIG. 4 are illustrative in nature, and any other suitable temporal durations can alternatively or additionally be used. In some embodiments, the example process 400 can be performed and completed by the wireless charging system 300 within approximately 660 ms. [0072] In some embodiments, during the phase 402, the charging configuration determination module 306 may cause the wireless charging system 300 to perturb the ground pad coil 312 to estimate a self-resonance frequency of the vehicle pad coil 314. More specifically, during a first portion 406 of the phase 402, the charging configuration determination module 306 may short (e.g., through closing an electrical switch to form a short circuit) the vehicle pad coil 314 and perform a frequency sweep (e.g., injecting various electrical signals having various signal frequencies into the ground pad coil 312) of signals over a frequency range on the ground pad coil 312. For example, the charging configuration determination module 306 may apply a plurality of signal waveforms to the ground pad coil 312 sequentially and non- overlapping in time while shorting the vehicle pad coil 314. Each of the plurality of signal waveforms may correspond to a distinct signal frequency. During application of each of the plurality of signal waveforms, a peak current through the ground pad coil 312 may be measured. A signal waveform that results in the smallest peak current through the ground pad coil 312 can be identified by the charging configuration determination module 306. A signal frequency of the signal waveform can be selected as the self-resonance frequency of the vehicle pad coil 314. [0073] For example, as illustrated in the first portion 406 of the phase 402, N (e.g., a positive integer greater than or equal to two) signal waveforms are applied on the ground pad coil 312 while the vehicle pad coil 314 is shorted. A first signal waveform 402-1 (e.g., a square waveform, a triangle waveform, or any other suitable type of signal waveform) may have a first signal frequency (e.g., 50 kHz), a second signal waveform 402-2 may have a second signal frequency (e.g., 55 kHz), and a N^th signal waveform 402-N may have a N^th signal frequency. The first signal waveform 402-1 may be applied to the ground pad coil 312 for a particular time period (e.g., 3 milliseconds). For the particular time period when the first signal waveform 402-1 is applied, the charging configuration determination module 306 may measure a first peak current through the ground pad coil 312. After a waiting period (e.g., 1 millisecond), the second signal waveform 402-2 may be applied to the ground pad coil 312 for the particular time period. For the particular time period when the second signal waveform 402-2 is applied, the charging configuration determination module 306 may measure a second peak current through the ground pad coil 312. The above waveform application and peak current measurement process may be continued until the N^th signal waveform 402-N is applied to the ground pad coil 312, and the N^th peak current through the ground pad coil 312 is measured. The charging configuration determination module 306 may select a signal frequency of one of the signal waveforms 402-1, 402-2 through 402-N that results in the smallest peak current as the self-resonance frequency of the vehicle pad coil 314. For example, if the second peak current is smaller than all the other peak currents, the second signal frequency of the second signal waveform 402-2 may be selected as the self-resonance frequency of the vehicle pad coil 314. In some embodiments, the first portion 406 of the phase 402 may last for approximately 100 milliseconds. [0074] During the second portion 408 of the phase 402, the charging configuration determination module 306 may measure a peak steady state current (e.g., i2p in equation (4) below) through the vehicle pad coil 314 by operating the converter 310 under the self- resonance frequency of the vehicle pad coil 314 obtained during the first portion 406 of the phase 402. For example, the charging configuration determination module 306 may cause the wireless charging system 300 to apply or inject a signal waveform generated using the self- resonance frequency of the vehicle pad coil 314 to the ground pad coil 312, and measure a peak current through the vehicle pad coil 314 to obtain the peak steady state current through the vehicle pad coil 314 associated with the signal waveform being applied to the ground pad coil 312. In some embodiments, the second portion 408 may be completed within approximately 500 ms. [0075] Based on the self-resonance frequency of the vehicle pad coil 314 and/or the peak steady state current measured during the second portion 408 of the phase 402, the self-inductance L2 of the vehicle pad coil 314 and other parameters may be obtained at operation 410. The self-inductance L2 of the vehicle pad coil 314 can be determined after determining the self-resonance frequency of the vehicle pad coil 314. For example, the self- inductance L2 of the vehicle pad coil 314 may be calculated via the use of equation (1), where fsw1 is the self-resonance frequency of the vehicle pad coil 314, Cvp is the coupling capacitance of the vehicle pad coil 314. [0076] L2 = ^^^^^ʌf_sw1)² C_vp) (1) [0077] During the phase 404, the charging configuration determination module 306 may cause the wireless charging system 300 to perturb the vehicle pad coil 314 to estimate a self-resonance frequency of the ground pad coil 312. More specifically, during the phase 404, the charging configuration determination module 306 may cause the wireless charging system 300 to short the ground pad coil 312 and perform a frequency sweep (e.g., injecting various electrical signals having various signal frequencies into the vehicle pad coil 314) of signals over a frequency range on the vehicle pad coil 314. For example, the charging configuration determination module 306 may cause the wireless charging system 300 to apply a plurality of signal waveforms to the vehicle pad coil 314 sequentially and non-overlapping in time while shorting the ground pad coil 312. Each of the plurality of signal waveforms may correspond to a distinct signal frequency. For application of each of the plurality of signal waveforms, a peak current through the vehicle pad coil 314 may be measured. A signal waveform that results in the smallest peak current through the vehicle pad coil 314 can be identified. A signal frequency of the signal waveform can be selected as the self-resonance frequency of the ground pad coil 312. [0078] As illustrated in the phase 404, M (e.g., a positive integer greater than or equal to two) signal waveforms are applied on the vehicle pad coil 314 while the ground pad coil 312 is shorted. A first signal waveform 404-1 (e.g., a square waveform, a triangle waveform, or other types of signal waveforms) may have a first signal frequency (e.g., 50 kHz), a second signal waveform 404-2 may have a second signal frequency (e.g., 55 kHz), and a M^th signal waveform 404-M may have a M^th signal frequency. The first signal waveform 404-1 may be applied to the vehicle pad coil 314 for a particular time period (e.g., 3 milliseconds). During the particular time period when the first signal waveform 404-1 is applied, the charging configuration determination module 306 may measure a first peak current through the vehicle pad coil 314. After a waiting period (e.g., 1 millisecond), the second signal waveform 404-2 may be applied to the vehicle pad coil 314 for the particular time period. During the particular time period when the second signal waveform 404-2 is applied, the charging configuration determination module 306 may measure a second peak current through the vehicle pad coil 314. The above waveform application and peak current measurement process may be continued until the M^th signal waveforms 404-M is applied to the vehicle pad coil 314, and the M^th peak current through the vehicle pad coil 314 is measured. The charging configuration determination module 306 may select a signal frequency of one of the signal waveforms 404-1, 404-2 through 404-M that results in the smallest peak current as the self- resonance frequency of the ground pad coil 312. For example, if the first peak current is smaller than all the other peak currents, the first signal frequency of the first signal waveform 404-1 may be selected as the self-resonance frequency of the ground pad coil 312. [0079] Based on the self-resonance frequency of the ground pad coil 312 estimated and/or calculated during the phase 404, the self-inductance L1 of the ground pad coil 312 may be obtained at operation 412. The self-inductance L1 of the ground pad coil 312 can be determined after determining the self-resonance frequency of the ground pad coil 312. For example, the self-inductance L1 of the ground pad coil 312 may be calculated via the use of equation (2), where fsw2 is the self-resonance frequency of the ground pad coil 312, Cgp is the coupling capacitance of the ground pad coil 312. As another example, the turns ratio n can be determined based on the self-inductance L1 of the ground pad coil 312 and the self-inductance L2 of the vehicle pad coil 314. More specifically, the turns ratio n may be calculated via the use of equation (3), taking the square root of the quotient of the self-inductance L1 of the ground pad coil 312 divided by the self-inductance L2 of the vehicle pad coil 314. As still another example, the reactance Xa can be determined based on the coupling capacitance C_vp of the vehicle pad coil 314, the turns ratio n, and an inductive current i2p through the vehicle pad coil 314. More specifically, via the use of equation (4), the reactance Xa can be determined by dividing the product of coupling capacitance Cvp and the turns ratio n by the inductive current i2p. As yet another example, the coupling coefficient k can be determined based on the reactance Xa, the self-inductance L1 of the ground pad coil 312, and the self-resonance frequency f_sw2 of the ground pad coil 312 using equation (5). [0080] L1 = ^^^^^ʌf_sw2)² C_gp) (2) [0081] n = sqrt (L1/L2) (3) [0084] Utilizing the example process 400, the charging configuration determination module 306 may update one or more wireless charging settings for the wireless charging system 300. More specifically, based at least on the set of parameters (e.g., the self- inductance L1, the self-inductance L2, the turns ratio n, or the like) associated with the circuit model, the charging configuration determination module 306 may update or adjust one or more wireless charging settings (e.g., operating frequency of the converter 310, a power limit for the wireless charging system 300, or a DC voltage level applied at a ground pad 302 of the wireless charging system 300) to accomplish efficient and safe operations of wireless charging. For example, if the self-inductance L1 of the ground pad coil 312 deviates upward due to variations caused by environmental conditions (e.g., because of nearby ferrous objects), the charging configuration determination module 306 may reduce the DC voltage level applied at the ground pad 302 for charging. [0085] In this way, the wireless charging system 300 may charge the vehicle 112 more efficiently compared to without estimating any of the parameters of wireless charging. The wireless charging system 300 may include one or more processors using firmware to perform the example process 400 described herein. Further Example of Circuit Model and Parameter Estimation Process [0086] FIG. 5A illustrates an example circuit topology 500A of the converter 310 in accordance with some embodiments of the present disclosure. The circuit topology 500A represents a bidirectional CLLC resonant Dual-Active-Bridge (DAC) converter including two H bridge circuits. More specifically, the transistors 502, 504, 506, and 508 form a first H bridge circuit on a ground pad, and the transistors 522, 524, 526, and 528 form a second H bridge circuit on a vehicle pad. As shown in FIG. 5A, a ground pad coil 512 and a compensation capacitor 516 are connected in series on the ground pad. One end of the ground pad coil 512 is connected to a node 544 of the first H bridge circuit that includes the transistors 502, 504, 506, and 508, and one end of the compensation capacitor 516 is connected to a node 542 of the first H bridge circuit. On the vehicle pad, a vehicle pad coil 514 and a compensation capacitor 518 are connected in series. One end of the vehicle pad coil 514 is connected to a node 546 of the second H bridge circuit that includes the transistors 522, 524, 526, and 528, and one end of the compensation capacitor 518 is connected to a node 548 of the second H bridge circuit. [0087] As illustrated in FIG. 5A, a ground pad voltage (denoted as V_GP+ and V_GP-) can be applied and/or measured across a terminal 552 and a terminal 554 of the first H bridge circuit that includes the transistors 502, 504, 506, and 508. A capacitor 572 can be shunted across the terminal 552 and the terminal 554 on the ground pad. A vehicle pad voltage (denoted as V_VP+ and V_VP-) can be applied and/or measured across a terminal 558 and a terminal 556 of the second H bridge circuit that includes the transistors 522, 524, 526, and 528. A capacitor 574 can be shunted across the terminal 558 and the terminal 556 of the vehicle pad. [0088] In wireless power transfer, a coil equivalent self-inductance can vary from its nominal value due to misalignment. Accordingly, it can be desirable to estimate the coil equivalent self-inductance before and/or at a beginning of a charging cycle for better control and performance of wireless charging. As shown in FIG. 5A, the ground pad coil 512 has a self-inductance L1, and the vehicle pad coil 514 has a self-inductance L2. The compensation capacitor 516 has a capacitance of C₁, and the compensation capacitor 518 has a capacitance of C2. A current ^_^(t) (also referred to as flows through a resonant tank formed by the ground pad coil 512 and the compensation capacitor 516, and a current ^_ଶ(t) (also referred to as ^_ଶ) flows through a resonant tank formed by the vehicle pad coil 514 and the compensation capacitor 518. Further, the ground pad coil 512 and the vehicle pad coil 514 have a coupling coefficient k. In some embodiments, the resonant tank that includes the ground pad coil 512 and compensation capacitor 516, and the resonant tank that includes the vehicle pad coil 514 and compensation capacitor 518 are designed such that the self-resonance frequency of the vehicle pad coil 514 and the self-resonance frequency of the ground pad coil 512 are close to each other. In some embodiments, the coupling coefficient is k can be between 0.1 to 0.3. [0089] FIG. 5B illustrates an example circuit model 500B that models the circuit topology 500A in accordance with some embodiments of the present disclosure. As shown in FIG. 5B, the ground pad bus voltage (denoted as V_GP+ and V_GP- in FIG. 5A) is modeled as _^^(t) (also referred to as _^^), and the vehicle pad bus voltage (denoted as V_VP+ and V_VP- in FIG. 5B) is modeled as _^ (t) (also referred to as _^). Further, the first H bridge circuit that includes the transistors 502, 504, 506, and 508 is modeled by a transfer function _^^(t) (also referred to as _^^), and the second H bridge circuit that includes the transistors 522, 524, 526, and 528 is modeled by a transfer function ^_ଶ(t) (also referred to as ^_ଶ). As shown in FIG. 5B, n represents an effective turns ratio from the ground pad coil 512 to the vehicle pad coil 514. [0090] FIG. 6 illustrates an example process 600 for estimating and/or calculating parameters and/or variables associated with the circuit model 500B. The process 600 can involve a parameter estimation sequence that may be a portion of a charging configuration determination procedure. The parameter estimation sequence can be performed at a beginning of each charging session. In some embodiments, the example process 600 may be implemented and/or directed by the charging configuration determination module 306 to determine parameters and/or variables associated with the circuit model 500B. As shown in FIG. 6, the process 600 may include a ground pad phase 602 and a vehicle pad phase 604. Although the ground pad phase 602 is illustrated to be performed before the vehicle pad phase 604, the vehicle pad phase 604 may be performed before the ground pad phase 602 in other embodiments. In some embodiments, the ground pad coil 512 and the vehicle pad coil 514 may be shorted during a portion 602-3, a portion 602-4, a portion 604-2, and a portion 604-3. [0091] During the ground pad phase 602, the charging configuration determination module 306 may cause the wireless charging system 300 to perturb the ground pad coil 512 to estimate a self-resonance frequency of the vehicle pad coil 514. More specifically, during a first portion 602-1 of the ground pad phase 602, the charging configuration determination module 306 may cause operations to be performed to short (e.g., through closing an electrical switch to form a short circuit) the vehicle pad coil 514 and perform a frequency sweep (e.g., perturbing the ground pad coil 512 by injecting various electrical signals having various signal frequencies into the ground pad coil 512) of signals over a frequency range on the ground pad coil 512. The charging configuration determination module 306 may increase and/or decrease frequencies of signals input to the ground pad coil 512 while measuring the current ^_^ flowing through the ground pad coil 512. A frequency at which the current ^_^ reaches a minimum value (e.g., zero) is the self-resonance frequency of the vehicle pad coil 514. During a second portion 602-2 of the ground pad phase 602, the charging configuration determination module 306 may measure the current ^_ଶ flowing through the vehicle pad coil 514 when operating the converter 310 under the self-resonance frequency of the vehicle pad coil 514 that is obtained during the first portion 602-1 of the ground pad phase 602. During the portion 604-1 of the vehicle pad phase 604, the self-resonance frequency of the ground pad coil 512 can be obtained similarly to the first portion 602-1 of the ground pad phase 602, except by shorting the ground pad coil 512 and performing a frequency sweep on the vehicle pad coil 514. [0092] For example, the self-resonance frequency of the vehicle pad coil 514 may be obtained based on measuring the current ^_^ and using equations (6) – (8), where ^_^^ is the input impedance looking from the terminal 552 and the terminal 554 into the resonant tank that includes the ground pad coil 512 and the compensation capacitor 516, and equals 2^ _^^௪^. [0093] More specifically, when equation (8) holds true, ^_^^ would approach infinity, thereby resulting in ^_^ approaching zero based on the relationship of and ^_^^ as illustrated in equation (7). As such, by sweeping to a frequency that leads to ^_^ closest to or equal to zero, the frequency can be found as the self-resonance frequency f_sw1 of the vehicle pad coil 514. Based on the self-resonance frequency the self-inductance L2 of the vehicle pad coil 514 can be obtained using equation (9). Additionally, the self-inductance L1 of the ground pad coil 512 can be similarly obtained based on other equations that mirror equations (6) – (9). ^_ଶ = ^{^} ସ_{గమ^మ ೞ^భ ^మ} (9) [0094] As another example, the coupling coefficient k can be determined based on equation (10), where ^_ଶ denotes current flowing through the vehicle pad coil 514 when (e.g., during the second portion 602-2 of the ground pad phase 602) the resonant tank that includes the vehicle pad coil 514 operates under the self-resonance frequency fsw1 of the vehicle pad coil 514. When the vehicle pad coil 514 operates under the self-resonance frequency fsw1, ^_ଶ can be expressed using equation (11). [0095] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims. Conclusion [0096] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims. [0097] It is to be understood that not necessarily all objects or advantages may be achieved in accordance with any particular example described herein. Thus, for example, those skilled in the art will recognize that some examples may be operated in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. [0098] All of the processes described herein may be embodied in, and fully automated via, software code modules executed by a computing system that includes computers or processors. The code modules may be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all the methods may be embodied in specialized computer hardware. [0099] Many other variations than those described herein will be apparent from this disclosure. For example, depending on the example, some acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (for example, not all described acts or events are necessary for the practice of the algorithms). Moreover, in some examples, acts or events can be performed concurrently, for example, through multi-threaded processing, interrupt processing, or multiple processors or processor cores, or on other parallel architectures, rather than sequentially. In addition, different tasks or processes can be performed by different machines and/or computing systems that can function together. [0100] The various illustrative logical blocks and modules described in connection with the examples disclosed herein can be implemented or performed by a machine, such as a processing unit or processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor can be a microprocessor, but in the alternative, the processor can be a controller, microcontroller, or state machine, combination of the same, or the like. A processor can include electrical circuitry to process computer-executable instructions. In some examples, a processor includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few. [0101] The elements of a method, process, routine, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor device, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory computer-readable storage medium. An exemplary storage medium can be coupled to the processor device such that the processor device can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor device. The processor device and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor device and the storage medium can reside as discrete components in a user terminal. [0102] The processes described herein or illustrated in the figures of the present disclosure may begin in response to an event, such as on a predetermined or dynamically determined schedule, on demand when initiated by a user or system administrator, or in response to some other event. When such processes are initiated, a set of executable program instructions stored on one or more non-transitory computer-readable media (e.g., hard drive, flash memory, removable media, etc.) may be loaded into memory (e.g., RAM) of a server or other computing device. The executable instructions may then be executed by a hardware-based computer processor of the computing device. In some embodiments, such processes or portions thereof may be implemented on multiple computing devices and/or multiple processors, serially or in parallel. [0103] Conditional language such as, among others, “can,” “could,” “might” or “may,” unless specifically stated otherwise, are otherwise understood within the context as used in general to convey that some examples include, while other examples do not include, some features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way for examples or that examples necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular example. [0104] Disjunctive language such as the phrase “at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (for example, X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that some examples require at least one of X, at least one of Y, or at least one of Z to each be present. [0105] Any process descriptions, elements or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include executable instructions for implementing specific logical functions or elements in the process. Alternate examples are included within the scope of the examples described herein in which elements or functions may be deleted, executed out of order from that shown, or discussed, including substantially concurrently or in reverse order, depending on the functionality involved as would be understood by those skilled in the art. [0106] It should be emphasized that many variations and modifications may be made to the above-described examples, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. [0107] Any process descriptions, elements or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include executable instructions for implementing specific logical functions or elements in the process. Alternate implementations are included within the scope of the examples described herein in which elements or functions may be deleted, executed out of order from that shown, or discussed, including substantially concurrently or in reverse order, depending on the functionality involved as would be understood by those skilled in the art. [0108] Unless otherwise explicitly stated, articles such as “a” or “an” should generally be interpreted to include one or more described items. Accordingly, phrases such as “a device configured to” are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations. For example, “a processor configured to carry out recitations A, B, and C” can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C.

Claims

WHAT IS CLAIMED IS: 1. A wireless charging system comprising: a first coil; and a charging configuration determination module comprising circuitry configured to cause a charging configuration determination procedure to be performed, the charging configuration determination procedure comprising: perturbing the first coil, wherein the first coil is inductively coupled with a second coil; estimating one or more circuit parameters of a converter that comprises the first coil and the second coil based on the perturbing; and configuring one or more wireless charging settings of the wireless charging system based on the one or more circuit parameters, wherein the wireless charging system is configured to charge a battery pack of a vehicle based on wireless transfer of power between the first coil and the second coil.

2. The wireless charging system of Claim 1, wherein the first coil is in a ground pad, and wherein the second coil is in a vehicle pad attached to the vehicle.

3. The wireless charging system of Claim 1, wherein perturbing the first coil comprises: shorting the second coil; applying sequentially in time a plurality of signal waveforms to the first coil, wherein each of the plurality of signal waveforms is generated based on a frequency of a plurality of frequencies; measuring a peak current through the first coil when each of the plurality of signal waveforms is applied to the first coil; and selecting one of the plurality of frequencies that corresponds to a minimum peak current through the first coil as a self-resonance frequency of the second coil.

4. The wireless charging system of Claim 3, wherein perturbing the first coil comprises: applying a signal waveform generated based on the self-resonance frequency of the second coil to the first coil; and measuring a peak current through the second coil to obtain a peak steady state current when the signal waveform is applied to the first coil.

5. The wireless charging system of Claim 4, wherein estimating the one or more circuit parameters is further based on the peak steady state current.

6. The wireless charging system of Claim 1, wherein the charging configuration determination procedure further comprises perturbing the second coil.

7. The wireless charging system of Claim 6, wherein perturbing the first coil and perturbing the second coil are performed non-overlapping in time.

8. The wireless charging system of Claim 1, wherein the one or more circuit parameters comprise one or more of a self-inductance of the first coil, a self-inductance of the second coil, a reactance associated with the first coil, a coupling coefficient associated with the first coil and the second coil, or a turns ratio associated with the converter.

9. The wireless charging system of Claim 1, wherein the one or more circuit parameters comprise a self-inductance of the first coil and a self-inductance of the second coil.

10. The wireless charging system of Claim 1, wherein the one or more circuit parameters comprise a coupling coefficient associated with the first coil and the second coil.

11. The wireless charging system of Claim 1, wherein the one or more wireless charging settings comprises one or more of an operating frequency of the converter, a power limit for the wireless charging system, or a DC voltage level applied at a ground pad of the wireless charging system.

12. The wireless charging system of Claim 1, wherein the charging configuration determination procedure is performed at a beginning of a wireless charging sequence.

13. The wireless charging system of Claim 1, wherein the charging configuration determination procedure further comprises charging the battery pack of the vehicle according to the one or more wireless charging settings.

14. The wireless charging system of Claim 1, wherein the charging configuration determination procedure further comprises causing an air suspension system of the vehicle to lower a vehicle body of the vehicle.

15. A method of wireless charging, the method comprising: perturbing a first coil, wherein the first coil is inductively coupled with a second coil; estimating one or more circuit parameters of a converter that comprises the first coil and the second coil based on the perturbing; and configuring one or more wireless charging settings of a wireless charging system based on the one or more circuit parameters, wherein the wireless charging system is configured to charge a battery pack of a vehicle based on wireless transfer of power between the first coil and the second coil.

16. The method of Claim 15, further comprising wirelessly charging the battery pack of the vehicle according to the one or more wireless charging settings.

17. A method of wireless charging, the method comprising: perturbing a first coil of a converter of a wireless charging system; estimating a self-resonance frequency of a second coil of the converter of the wireless charging system based on the perturbing the first coil; estimating a self-resonance frequency of the first coil based on the second coil being perturbed; calculating, based at least on the self-resonance frequency of the first coil and the self-resonance frequency of the second coil, one or more parameters associated with the converter; and setting one or more wireless charging settings for the wireless charging system based at least on the one or more parameters associated with the converter.

18. The method of Claim 17, wherein perturbing the first coil to estimate the self- resonance frequency of the second coil comprises: shorting the second coil; applying sequentially in time a plurality of signal waveforms to the first coil, wherein each of the plurality of signal waveforms is generated based on a frequency of a plurality of frequencies; measuring a peak current through the first coil when each of the plurality of signal waveforms is applied to the first coil; and selecting one of the plurality of frequencies that corresponds to a minimum peak current through the first coil as the self-resonance frequency of the second coil.

19. The method of Claim 18, wherein perturbing the first coil to estimate the self- resonance frequency of the second coil comprises: applying a signal waveform generated based on the self-resonance frequency of the second coil to the first coil; and measuring a peak current through the second coil to obtain a peak steady state current when the signal waveform is applied to the first coil.

20. The method of Claim 19, wherein calculating the one or more parameters is further based on the peak steady state current.

21. The method of Claim 17, wherein perturbing the first coil is performed before or after in time the second coil being perturbed.

22. The method of Claim 17, further comprising charging a battery pack of a vehicle using the one or more wireless charging settings.

23. Computer-readable storage comprising instructions stored thereon that, when executed by circuitry of a wireless charging system, cause the method of Claim 17 to be performed.