Switching the control method of wireless charging devices

Abstract

This invention provides a method for wirelessly charging batteries for electric vehicles and the like, as well as a wireless charging pad. [Solution] The wireless charging pad includes an H-bridge circuit, a resonant tank electrically connected to the H-bridge circuit, and a switch control circuit. The resonant tank includes a coil arranged for wireless power transmission. The switch control circuit controls the H-bridge circuit using both a first modulation and a second modulation. The first modulation includes two non-zero switch configurations and two different zero switch configurations. The second modulation includes two non-zero switch configurations and two different zero switch configurations in a sequence different from the first modulation.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the priority of U.S. Provisional Patent Application No. 63 / 705,322, filed on October 9, 2024, with the title "SWITCH CONTROL SCHEME FOR WIRELESS CHARGING DEVICE" and U.S. Patent Application No. 19 / 313,624, filed on August 28, 2025, with the title "SWITCH CONTROL SCHEME FOR WIRELESS CHARGING DEVICE", the technical disclosures of which are hereby incorporated by reference in their entirety for all purposes.

[0002] This disclosure relates to systems and methods for wireless charging. More specifically, embodiments of this disclosure relate to methods for controlling wireless charging and wireless charging circuit signals.

Background Art

[0003] Batteries are components of a wide range of battery - powered devices, equipment, or various transportation platforms, such as electric vehicles, robots, electric bikes, electric motorcycles, drones, and many other types of devices. Batteries can be configured to be paired with a wireless charging device and receive energy via electromagnetic coupling between a receiving pad and the wireless charging device. Specifically, a wireless charging device can use one or more internal coils to induce an electromagnetic field, and one or more corresponding receiving coils connected to the battery can capture these electromagnetic fields within a certain proximity distance from the charging device. There are various technical challenges related to wireless charging.

Summary of the Invention

[0004] Each of the systems, methods, and devices disclosed herein has several innovative embodiments, and not just one of them alone is responsible for all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described herein are given in the accompanying drawings and the following description.

[0005] In some embodiments, the technology described herein relates to a method of wireless power transmission, the method comprising: controlling an H-bridge circuit of a grounding pad using a first modulation constituting an H-bridge, the first modulation comprising two non-zero switch configurations and two different zero switch configurations, the two non-zero switch configurations comprising a positive switch configuration and a negative switch configuration; transitioning the control of the H-bridge circuit from the first modulation to a second modulation, the second modulation comprising two non-zero switch configurations and two different zero switch configurations in a different order than the first modulation; and performing wireless power transmission from the grounding pad to a vehicle pad of a vehicle using the H-bridge circuit.

[0006] In some embodiments, the techniques described herein relate to a method in which the transition control of an H-bridge circuit from a first modulation to a second modulation occurs temporally between two non-zero switch configurations.

[0007] In some embodiments, the techniques described herein relate to methods in which a first modulation controls an H-bridge circuit in a sequence in which each transition between switching configurations related to the sequence includes turning one switch on and turning one switch off.

[0008] In some embodiments, the techniques described herein relate to methods in which both the first and second modulations provide the same output voltage waveform from an H-bridge circuit.

[0009] In some embodiments, the techniques described herein relate to methods in which the first modulation includes operating an H-bridge circuit in two non-zero-switch configurations for a longer duration than in two different zero-switch configurations.

[0010] In some embodiments, the techniques described herein relate to methods in which a first modulation controls an H-bridge circuit in a first sequence in which a positive switch configuration is followed by a first switch configuration of two different zero switch configurations, and a second modulation controls an H-bridge circuit in a second sequence in which a positive switch configuration is followed by a second switch configuration of two different zero switch configurations.

[0011] In some embodiments, the techniques described herein relate to methods in which a first modulation controls an H-bridge circuit in a first sequence in which a second zero-switch configuration of two different zero-switch configurations follows a positive-switch configuration, and a second modulation controls an H-bridge circuit in a second sequence in which a first zero-switch configuration of two different zero-switch configurations follows a positive-switch configuration.

[0012] In some embodiments, the techniques described herein relate to methods in which the H-bridge circuit is controlled by a first modulation for at least 50% of the wireless charging cycle.

[0013] In some embodiments, the techniques described herein relate to methods, further comprising transitioning the control of an H-bridge circuit from a second modulation to a third modulation, the third modulation including two non-zero-switch configurations and only the first of two different zero-switch configurations.

[0014] In some embodiments, the techniques described herein relate to methods, further comprising transitioning the control of an H-bridge circuit from a second modulation to a fourth modulation, the fourth modulation including two non-zero-switch configurations and only the second of two different zero-switch configurations.

[0015] In some embodiments, the technique described herein relates to a method further comprising determining, at least in part, on a temperature associated with the H-bridge circuit, that the H-bridge circuit should transition from a first modulation to a second modulation, and the transition control of the H-bridge circuit from the first modulation to the second modulation is performed in response to the determination.

[0016] In some embodiments, the techniques described herein relate to methods, further comprising determining the frequency of the transition control of the H-bridge circuit from a first modulation to a second modulation, at least in part, based on the temperature associated with the H-bridge circuit.

[0017] In some embodiments, the technology described herein relates to a method of wireless power transmission, the method comprising controlling a switching circuit of a wireless charging pad with a first modulation that constitutes a switching circuit, the first modulation comprising two non-zero switch configurations and two different zero switch configurations, the two non-zero switch configurations comprising a positive switch configuration and a negative switch configuration, and transitioning the control of the switching circuit from the first modulation to a second modulation, the second modulation comprising two non-zero switch configurations and two different zero switch configurations in a different order than the first modulation, the switching circuit receiving a voltage related to wireless reception from another wireless charging pad.

[0018] In some embodiments, the techniques described herein relate to methods in which the transition control of a switching circuit from a first modulation to a second modulation occurs temporally between two non-zero switch configurations.

[0019] In some aspects, the technology described herein relates to a wireless charging pad, the wireless charging pad including an H-bridge circuit, a resonant tank electrically connected to the H-bridge circuit and including a coil arranged for wireless power transmission, and a switch control circuit configured to control the H-bridge circuit using both a first modulation and a second modulation, the first modulation including two non-zero switch configurations and two different zero-switch configurations, and the second modulation including two non-zero switch configurations and two different zero-switch configurations in an order different from the first modulation.

[0020] In some aspects, the technology described herein relates to a wireless charging pad, the wireless charging pad being a ground pad.

[0021] In some aspects, the technology described herein relates to a wireless charging pad, the wireless charging pad being a vehicle pad.

[0022] In some aspects, the technology described herein relates to a wireless charging pad, the wireless charging pad being configured for wireless power transmission related to charging a battery pack of a vehicle, the battery pack having an operating voltage in the range of 200 volts to 800 volts.

[0023] In some aspects, the technology described herein relates to a wireless charging pad, and controlling the H-bridge circuit includes transitioning control of the H-bridge circuit from the first modulation to the second modulation.

[0024] In some aspects, the technology described herein relates to a wireless charging pad, and the transition control of the H-bridge circuit from the first modulation to the second modulation occurs temporally between one of the two non-zero switch configurations.

Brief Description of the Drawings

[0025] These and other features, aspects, and advantages of the present disclosure will be described with reference to the drawings of particular embodiments. It should be understood that the accompanying drawings, which are incorporated herein and constitute a part of this specification, are for the purpose of illustrating the concepts disclosed herein and may not be to scale.

[0026] [Figure 1A] An exemplary wireless charging environment in which embodiments of the present disclosure can be implemented is shown.

[0027] [Figure 1B] FIG. 1A is a block diagram showing an exemplary wireless charging environment according to some embodiments of the present disclosure.

[0028] [Figure 1C] A diagram of a ground pad that can function as a wireless charging device according to some embodiments of the present disclosure is shown.

[0029] [Figure 2] FIGS. 2A-2D show exemplary circuit schematic diagrams of a wireless charging system according to some embodiments of the present disclosure.

[0030] [Figure 3] An exemplary block diagram of a wireless charging pad according to some embodiments of the present disclosure is shown.

[0031] [Figure 4A] An exemplary switch configuration of the H-bridge circuit of the wireless charging pad of FIG. 3 according to some embodiments of the present disclosure is shown. [Figure 4B] An exemplary switch configuration of the H-bridge circuit of the wireless charging pad of FIG. 3 according to some embodiments of the present disclosure is shown. [Figure 4C] An exemplary switch configuration of the H-bridge circuit of the wireless charging pad of FIG. 3 according to some embodiments of the present disclosure is shown. [Figure 4D] An exemplary switch configuration of the H-bridge circuit of the wireless charging pad of FIG. 3 according to some embodiments of the present disclosure is shown.

[0032] [Figure 5] Figures 5A and 5B show the switch configuration for controlling the H-bridge circuit.

[0033] [Figure 6] Figures 6A and 6B show examples of switch configurations for controlling an H-bridge circuit according to some embodiments of the present disclosure.

[0034] [Figure 7] This shows a switch configuration where the transition between the two modulation schemes is not smooth.

[0035] [Figure 8] This embodiment of the disclosure shows a switching configuration that provides smooth interplay between two modulation schemes.

[0036] [Figure 9] An exemplary diagram of a switch control circuit connected to a switch according to an embodiment of the present disclosure is shown. [Modes for carrying out the invention]

[0037] The following detailed descriptions of specific embodiments present various descriptions of those specific embodiments. However, the technological innovations described herein can be implemented in numerous different ways, for example, as defined and encompassed by the claims. In this description, similar reference numbers and / or terms refer to drawings in which identical or functionally similar elements may be shown. It will be understood that the elements shown in the drawings are not necessarily drawn to scale. Furthermore, it will be understood that a particular embodiment may include more elements and / or subsets of elements shown in the drawings than those shown. In addition, some embodiments may incorporate any suitable combination of features from two or more drawings. The headings provided herein are for convenience only and do not necessarily affect the claims or their meaning.

[0038] Introduction Aspects of this disclosure relate to systems and methods for wirelessly charging a battery pack via wireless power transmission. More specifically, this disclosure relates to alternating modulation schemes for controlling electrical circuit components of a wireless charging device designed to charge a battery pack. Exemplary, the electrical circuit components of a wireless charging device may include a circuit that generates an alternating current (AC) signal by inverting a direct current (DC) signal to an alternating current (AC) signal. Such a circuit may have a bridge topology, such as an H-bridge. In some embodiments, the circuit may include a plurality of switches. By controlling the operation of each of these switches, the DC signal can be inverted to an AC signal. For example, a DC signal (e.g., the input signal of an H-bridge) can be inverted to a positive, negative, or zero voltage by opening and closing each switch in the circuit. Generally, the DC signal is the input power to the wireless charging device and can be received from an external source such as a wall outlet or a solar cell.

[0039] In various embodiments, wireless charging devices can be used to charge vehicles such as electric vehicles having battery packs. In these embodiments, wireless charging devices can be implemented as grounding pads or vehicle pads. For example, to charge an electric vehicle, a grounding pad can be placed beneath the vehicle pad of the electric vehicle. A wireless charging DC / DC converter (also called an integrated DC / DC power converter) may include a DC / AC inverter in the grounding pad and an AC / DC rectifier in the vehicle pad. Power can be transmitted wirelessly from the grounding pad to the vehicle pad. In some embodiments, the vehicle pad can also transmit wireless power based on the reception of a DC signal from the vehicle's battery pack. For example, the vehicle pad can receive a DC signal from the battery pack and convert it to an AC signal.

[0040] Wireless charging devices can be used to wirelessly charge vehicles under a variety of operating environments or conditions. Low cost, high density, and operation over a wide range of ambient temperatures may be important for wireless charging of electric vehicles. For example, hot spot temperatures between semiconductor devices, such as device bridges, included in wireless charging devices can be one or more limiting factors for the total device die area, thermal management system, or associated cost, weight, and volume.

[0041] To address at least some of the technical problems described above, embodiments of the present disclosure relate to methods for reducing the hotspot temperature of semiconductor devices. More specifically, some embodiments of the present disclosure provide methods for reducing the hotspot temperature of semiconductor devices by balancing temperatures between semiconductor devices. The methods disclosed herein can balance the power loss of semiconductor devices, which may be important in wireless charging operations.

[0042] In some embodiments, the switch control circuit can be configured to control the switching mechanism of switches included in the H-bridge circuit of a wireless charging device. Each switch in the H-bridge circuit may include a semiconductor device such as a metal-oxide-semiconductor field-effect transistor (MOSFET). The control switching mechanism can balance the heat generated from each switch, particularly the conduction loss of the body diode, with the switching loss, which may mostly be the turn-off loss under zero-voltage switching. For example, during the operation of the wireless charging device, the on-time, turn-off current, and / or losses of the switches can be balanced. Thus, the temperature and power consumption between switches can be balanced without generating a hot spot temperature at a particular switch, and the maximum temperature associated with the switches can be reduced. Experiments have shown a temperature reduction of more than 10°C at hot spots by using the switching method disclosed herein.

[0043] In various embodiments disclosed herein, a switch control circuit can control a first switch and a second switch located on the first half-bridge of an H-bridge circuit to switch between an open and a closed state. The switch control circuit can also control a third switch and a fourth switch located on the second half-bridge of an H-bridge circuit to not switch. For example, the switch control circuit can control an H-bridge circuit to operate in a first switch configuration and a second switch configuration. In the first switch configuration, the first switch is closed, the second switch is open, the third switch is closed, and the fourth switch is open. When transitioning from the first configuration to the second switch configuration, the first switch is open, the second switch is closed, the third switch remains closed, and the fourth switch remains open.

[0044] In some embodiments, a switch control circuit can generate a modulated waveform for controlling the switches in an H-bridge. Such a modulated waveform can be generated by balancing the switching operation of the switches in the H-bridge. For example, each switch in the H-bridge can be turned on or off twice in each cycle of the modulated waveform, thereby closing the second and fourth switches (opening the first and third switches) during the first state of the cycle, closing the first and fourth switches (opening the second and third switches) during the second state of the cycle, closing the first and third switches (opening the second and fourth switches) during the third state of the cycle, and closing the second and third switches (opening the first and fourth switches) during the fourth state of the cycle. In some examples, balancing or alternating between different modes (e.g., different states) can be done over various durations (e.g., longer timescales). Exemplary timescales for balancing or alternating between different modes can include milliseconds, seconds, minutes, or hours. Therefore, the operation of each switch can be balanced in this modulated waveform, and by balancing the heat generation and power dissipation between switches, the hot spot temperature can be reduced. The above modulated waveform is just one example, and this disclosure discloses various modulated waveforms that can balance the heat generation and power dissipation between switches.

[0045] Some embodiments of the present disclosure further provide modulation schemes that can provide a smooth transition between two different modulation waveforms. For example, a switch control circuit may be configured to transition from a first modulation waveform to a second modulation waveform when the output voltage of an H-bridge circuit is positive or negative, by preventing the transition from occurring when the output voltage of the H-bridge is zero. This modulation waveform transition scheme can reduce and / or eliminate overvoltage or current transients in the resonant tank of a wireless charging device by providing a smooth transition. For example, a transition occurring at the zero output voltage of the H-bridge may result in an output voltage transient from zero to negative or zero to positive. This voltage change may result in an overvoltage or current voltage being applied from the H-bridge circuit to the resonant tank.

[0046] While various embodiments are described according to exemplary combinations of embodiments and features, those skilled in the art will understand that the examples and feature combinations are illustrative in nature and should not necessarily be construed as limiting. More specifically, embodiments of this application may be applicable to various types of vehicle charging mechanisms, power supplies, interfaces, etc. Furthermore, schematic diagrams of specific H-bridge circuits for charging batteries and / or battery packs under different voltage levels are described, but such schematic diagrams of exemplary H-bridge circuits should not necessarily be construed as limiting. Accordingly, those skilled in the art will understand that embodiments of this application are not necessarily limited to any particular type of vehicle, vehicle charging infrastructure, communications, or exemplary interactions between a vehicle, owner / user, and wireless battery charging system.

[0047] Overview of wireless charging In general, inductive charging, commonly referred to as wireless charging, is a type of wireless power transmission. Inductive charging uses electromagnetic induction to generate or supply electricity to a device without requiring a physical electrical connection. Specifically, various devices can be placed near a charging station or induction pad without the need for precise alignment or the creation of electrical contacts, physical docks, electrical plugs, etc. Such devices include, but are not limited to, vehicles, manufacturing equipment, household appliances, and medical devices.

[0048] According to embodiments of this application, an inductive charging system is configured to transmit energy via inductive coupling between its components. An exemplary charging system includes a transmission component which may be configured as a charging station or charging pad. A charging pad for wirelessly transmitting power to a vehicle may be called a grounding pad. An alternating current (e.g., input current) from a power source passes through an inductive coil in the charging station or pad. Based on the input current, moving charges passing through the inductive coil (e.g., grounding pad coil) generate (or induce) a magnetic field. Exemplarily, the strength of the magnetic field may vary at least in part with changes or fluctuations in the amplitude of the input current. The changing magnetic field generates an alternating current in an inductive coil on a receiving device (e.g., vehicle pad coil). The induced alternating current in the receiving device then passes through a rectifier which can convert the induced alternating current into a direct current. Finally, the receiving vehicle may include additional charging components and / or systems that utilize the converted direct current to charge a battery system, supply operating power, or a combination thereof.

[0049] When an exemplary inductive charging system uses resonant inductive coupling components / technologies, the distance between the grounding pad and the vehicle pad coil can be increased. More specifically, in some embodiments, a capacitor can be connected to each inductive coil to create two LC circuits having a specific resonant frequency. The frequency of the alternating current matches the resonant frequency. Furthermore, the matched frequency can be further selected depending on the typical distance between the transmitting and receiving devices, taking peak efficiency into consideration. In addition, the use of other materials for the receiving coil, such as silver-plated copper or sometimes aluminum, to minimize weight and reduce resistance can be utilized for the purpose of energy transmission efficiency.

[0050] Figure 1A shows an environment 100 for implementing an induction-based wireless charging system according to various embodiments of this application. Environment 100 can, exemplary, correspond to commercial implementations such as parking lots, parking spaces, and charging booths. Environment 100 can also correspond to personal or other non-commercial embodiments such as private homes. As an exemplary example, an embodiment of the induction-based wireless charging system in a non-commercial embodiment may include a grounding pad 102 configured to generate a variable magnetic field according to an induction charging methodology. As also shown in Figure 1A, the grounding pad 102, also called a transmitting component, may correspond to a standalone component that can be operated to be mounted or positioned on a floor 104 or another plane. In some other embodiments, the grounding pad 102 may be integrated or combined with other devices or components.

[0051] The grounding pad 102 can be connected to one or more power sources, such as inputs from a utility company, real-time power sources (e.g., solar or wind energy sources), energy storage cells, or a combination thereof. The power sources are configured to provide input alternating current as described herein. The grounding pad 102 can be connected to the power sources via direct electrical connections 106, such as via a junction box 108 located on the wall 118.

[0052] As shown in Figure 1A, in one embodiment, the grounding pad 102 corresponds to a form factor that allows placement on the floor 104 for wireless charging with a vehicle having a vehicle pad coil. The grounding pad 102 may have a form factor such that the vehicle can be positioned directly above the upper surface of the grounding pad 102. Exemplary, the dimensions of the grounding pad 102 (e.g., the height and width of the grounding pad 102) may be configured such that the distance between the upper surface of the grounding pad 102 and the bottom surface of the vehicle satisfies certain criteria such as the minimum distance between the grounding pad coil and the vehicle pad coil, and the maximum distance between the grounding pad coil and the vehicle pad coil. In some embodiments, the vehicle pad and / or grounding pad 102 (or combination thereof) may be configured with additional components for adjusting such distances (e.g., statically and / or dynamically) or otherwise changing the relative orientation between the grounding pad 102 and the vehicle.

[0053] In some embodiments, the grounding pad 102 can be configured to charge the vehicle's battery pack, which may have a nominal voltage exceeding 200 volts (e.g., a nominal voltage of about 350 or 355 volts) and a maximum voltage of 400 volts. In some embodiments, the grounding pad 102 can be configured to supply 800 volts of DC power. In some embodiments, the grounding pad 102 can supply voltages in the range of about 200 volts to 800 volts. The grounding pad 102 can wirelessly transmit enough power to charge the battery pack at such voltages.

[0054] Figure 1B shows a block diagram of an environment 100 including a wireless charging device 111 (e.g., a grounding pad 102) that wirelessly communicates with the vehicle 112 via an induction-based magnetic field or the like. The wireless charging device 111 is further connected to one or more energy sources 110. Although the wireless charging device 111 is shown as having a direct connection to the energy sources 110, at least a portion of the input AC can be provided via a wireless transmission method. Furthermore, in embodiments having multiple power sources, the environment may also include various switching components for selecting energy from individual energy sources 110 or combinations of energy sources 110.

[0055] Figure 1C shows a block diagram of a grounding pad 102 that can function as a wireless charging device 111 (shown in Figure 1B). The grounding pad 102 may include at least a grounding pad coil 122 for generating a magnetic field from an input current supplied from an energy source 110. As shown in Figure 1C, the input current can be supplied by a direct electrical connection 106.

[0056] In some embodiments, the grounding pad 102 may also include various sensor components 124A, 124B, 124C, and 124D related to the charging process. For example, sensor components 124A, 124B, 124C, and 124D may be configured for various functions such as vehicle detection, object detection, distance measurement to the vehicle, environmental sensors (e.g., temperature sensors, moisture sensors), and pressure sensors. In one embodiment, sensor components 124A, 124B, 124C, and 124D may include radar sensors. Sensor components 124A, 124B, 124C, and 124D may also include logic and processing components related to the charging process, including motion measurement, motion control, safety measurement, and communication components.

[0057] Wireless charging system with H-bridge circuit Figures 2A to 2D show schematic circuit diagrams of exemplary wireless charging systems 200A to 200D. As shown in Figures 2A to 2D, each of the wireless charging systems 200A to 200D may include a grounding pad (e.g., grounding pad 102) and a vehicle pad that is mounted on the vehicle or otherwise integrated with the vehicle. For example, the grounding pad of wireless charging system 200A may include a capacitor 212A, an H-bridge circuit 202A, and a resonant tank 204A, as shown in Figure 2A. The vehicle pad of wireless charging system 200A may include a capacitor 214A, an H-bridge circuit 208A, and a resonant tank 206A, as shown in Figure 2A. In some embodiments, power can be transmitted from a power source (not shown in Figure 2A) to the vehicle's battery pack (not shown in Figure 2A) via the H-bridge circuit 202A, resonant tank 204A, resonant tank 206A, and H-bridge circuit 208A. This power transmission may include wireless power transmission from the coil L1 of the grounding pad to the coil L2 of the vehicle pad. Any of the wireless charging systems 200A to 200D can be implemented according to any suitable principles and advantages disclosed herein.

[0058] Figure 2A shows a schematic circuit diagram of the wireless charging system 200A. As shown in Figure 2A, the wireless charging system 200A corresponds to an LCC-LCC circuit architecture. As shown in the figure, the wireless charging system 200A includes a capacitor 212A, an H-bridge circuit 202A, a resonant tank 204A, a resonant tank 206A, an H-bridge circuit 208A, and a capacitor 214A. In the LCC-LCC circuit architecture, the inductor L f1 and capacitor C f1 And C1 is coupled between the H-bridge circuit 202A and the grounding pad coil L1 in the grounding pad, and the inductor L f2 and capacitor C f2 And C2 is coupled between the H-bridge circuit 208A and the vehicle pad coil L2 in the vehicle pad.

[0059] Figure 2B shows a schematic circuit diagram of the wireless charging system 200B. As shown in Figure 2B, the wireless charging system 200B corresponds to an LCC series circuit architecture. As shown in the figure, the wireless charging system 200B includes a capacitor 212B, an H-bridge circuit 202B, a resonant tank 204B, a resonant tank 206B, an H-bridge circuit 208B, and a capacitor 214B. In the LCC series circuit architecture, the inductor L f1 and capacitor C f1 And C1 is coupled between the H-bridge circuit 202A and the grounding pad coil L1 in the grounding pad, and the series capacitor C2 is coupled between the H-bridge circuit 208A and the vehicle pad coil L2 in the vehicle pad.

[0060] Figure 2C shows a schematic circuit diagram of the wireless charging system 200C. As shown in Figure 2C, the wireless charging system 200C corresponds to a series LCC circuit architecture. As shown in the figure, the wireless charging system 200C includes a capacitor 212C, an H-bridge circuit 202C, a resonant tank 204C, a resonant tank 206C, an H-bridge circuit 208C, and a capacitor 214C. In the series LCC circuit architecture, the series capacitor C1 is coupled between the H-bridge circuit 202A and the grounding pad coil L1 in the grounding pad, and the inductor L f2 and capacitor C f2 And C2 is coupled between the H-bridge circuit 208A and the vehicle pad coil L2 in the vehicle pad.

[0061] Figure 2D shows a schematic circuit diagram of the wireless charging system 200D. As shown in Figure 2D, the wireless charging system 200D corresponds to a series-series circuit architecture. As shown in the figure, the wireless charging system 200D includes a capacitor 212D, an H-bridge circuit 202D, a resonant tank 204D, a resonant tank 206D, an H-bridge circuit 208D, and a capacitor 214D. In the series circuit architecture, the series capacitor C1 is coupled between the H-bridge circuit 202A and the grounding pad coil L1 in the grounding pad, and the series capacitor C2 is coupled between the H-bridge circuit 208A and the vehicle pad coil L2 in the vehicle pad.

[0062] Example: Wireless charging pad Figure 3 shows an exemplary wireless charging pad 300 according to several embodiments of the present disclosure. The wireless charging pad 300 includes an H-bridge circuit 322, a resonant tank 324, and a switch control circuit 326. The wireless charging pad 300 can charge a vehicle's battery pack over a relatively wide voltage range via a toggle switch in the H-bridge circuit 322. Any suitable principle and advantages of the wireless charging pad 300 can be implemented in the environment according to any suitable principle and advantages shown in Figures 1A to 1C.

[0063] The wireless charging pad 300 may be mounted on any grounding pad or vehicle pad of the wireless charging system 200A-200D to extend the operating voltage range and / or improve wireless charging efficiency. For example, the wireless charging pad 300 may be a grounding pad and / or vehicle pad of any of the wireless charging systems 200A-200D. In some embodiments, the H-bridge circuit 322 can correspond to any of the H-bridge circuits 202A, 208A, 202B, 208B, 202C, 208C, 202D, and 208D. The resonant tank 324 can correspond to any of the resonant tanks 204A, 206A, 204B, 206B, 204C, 206C, 204D, and 206D. The H-bridge circuit 322 is an example of a switching circuit. Any other suitable switching circuit can be used in accordance with any suitable principles and advantages disclosed herein. Such switching circuits may include half-bridge circuits.

[0064] As shown in Figures 4A to 4D, the H-bridge circuit 322 can include switches 322-1, 322-2, 322-3, and 322-4. In some embodiments, the switch control circuit 326 can control some of switches 322-1, 322-2, 322-3, and 322-4 to periodically switch between open and closed states, rather than periodically switching each of switches 322-1, 322-2, 322-3, and 322-4, while controlling some of switches 322-1, 322-2, 322-3, and 322-4 to remain open or closed without toggling. Thus, the switch control circuit 326 can configure switches 322-1 to 322-4 according to modulation schemes such as those shown in Figures 6A to 6C and 8, in order to enable the wireless charging pad 300 to charge the battery pack over a wider voltage range.

[0065] The switch control circuit 326 can provide control signals to control the state of the switches of the H-bridge circuit 322 (for example, switches 322-1 to 322-4 in Figures 4A to 4D). The switch control circuit 326 can be implemented by any suitable circuit for controlling the state of the switches of the H-bridge circuit 322. If the switches of the H-bridge circuit 322 (for example, the switches are FETs or IGBTs) have gates, the switch control circuit 326 can provide control signals to the gates of the H-bridge. In such cases, the switch control circuit 326 can be called a gate drive circuit.

[0066] Example H-bridge switch configuration Figures 4A to 4D show exemplary switch configurations of an H-bridge circuit 322 that can be controlled by a switch control circuit 326 according to some embodiments of the present disclosure. Figure 4A shows that the H-bridge circuit 322 can be configured by the switch control circuit 326 to a switch configuration 410 which can be called a positive configuration. Figure 4B shows that the H-bridge circuit 322 can be configured by the switch control circuit 326 to a switch configuration 420 which can be called a negative configuration. Figure 4C shows that the H-bridge circuit 322 can be configured by the switch control circuit 326 to a switch configuration 430 which can be called a zero-one configuration. Figure 4D shows that the H-bridge circuit 322 can be configured by the switch control circuit 326 to a switch configuration 440 which can be called a zero-two configuration.

[0067] The H-bridge circuit 322 includes four switches 322-1 (also referred to herein as "AP"), switch 322-2 (also referred to herein as "AN"), switch 322-3 (also referred to herein as "BN"), and switch 322-4 (also referred to herein as "BP"). These switches may be any suitable switches for power electronics such as n-type field-effect transistors configured to switch voltages sufficient for wireless charging disclosed herein. In certain applications, the H-bridge circuit 322 may include metal oxide field-effect transistors (MOSFETs). Alternatively or additionally, the H-bridge circuit 322 may include insulated-gate bipolar transistors (IGBTs). The H-bridge circuit 322 may include a first half-bridge and a second half-bridge. The first half-bridge may include switches 322-1 and 322-2. The second half-bridge may include switches 322-3 and 322-4.

[0068] As shown in Figure 4A, in switch configuration 410 (e.g., positive configuration), switch 322-1 is closed, switch 322-2 is open, switch 322-3 is closed, and switch 322-4 is open. As shown in Figure 4B, in switch configuration 420 (e.g., negative configuration), switch 322-1 is open, switch 322-2 is closed, switch 322-3 is open, and switch 322-4 is closed. As shown in Figure 4C, in switch configuration 430 (e.g., zero-one configuration), switch 322-1 is open, switch 322-2 is closed, switch 322-3 is closed, and switch 322-4 is open. As shown in Figure 4D, in switch configuration 440 (e.g., zero-two configuration), switch 322-1 is closed, switch 322-2 is open, switch 322-3 is open, and switch 322-4 is closed.

[0069] Example H-bridge switch configuration Figures 5A and 5B show two examples of modulation schemes, Modulation Scheme 1 and Modulation Scheme 2. Modulation Schemes 1 and 2 can be used as H-bridge circuits to control the waveform. Modulation Schemes 1 and 2 can be applied to H-bridge circuits implemented in grounding pads or vehicle pads. For example, the H-bridge circuits described with reference to Figures 5A and 5B can be any suitable H-bridge circuit in a wireless charging system (e.g., any of the H-bridge circuits 202A to 202D or 208A to 208D in Figures 2A to 2D). The switching configuration of the H-bridge circuit is described with reference to Figures 4A to 4D (configurations 410 to 440).

[0070] Figure 5A shows an example of a conceptual operating waveform applicable to H-bridge circuits 202A-202D (shown in Figures 2A-2D) or 208A-208D (shown in Figures 2A-2D). For convenience of explanation, the output voltage and current waveforms of the H-bridge circuit implemented on the grounding pad are denoted as V1 and I1, respectively. The output voltage and current waveforms of the H-bridge circuit implemented on the vehicle pad are denoted as V2 and I2, respectively.

[0071] Figure 5B maps the states of the H-bridge circuit to modulation scheme 1 and modulation scheme 2. As shown in Figure 5B, each of modulation schemes 1 and 2 generates a periodic waveform having four different states 510 to 540. As shown in Figure 5B, states 510, 520, 530, and 540 can be called zero, positive, zero, and negative states, respectively. In some embodiments, modulation schemes 1 and 2 can be implemented with various switch configurations corresponding to each state.

[0072] In some embodiments, in modulation scheme 1, state 510 can be generated by configuring an H bridge in the zero-one switch configuration 430 shown in Figure 4C. In configuration 430, switches 322-2 (AN) and 322-3 (BN) are turned on, and switches 322-1 (AP) and 322-4 (BP) are turned off. Next, by turning off switch 322-2 (AN) and turning on switch 322-1 (AP), a transition can be made from state 510, which corresponds to switch configuration 430, to state 520, which corresponds to switch configuration 410. State 520 can be called the positive state. In the positive state, the H bridge is in the positive switch configuration 410 shown in Figure 4A. In the positive switch configuration 410, switches 322-1 (AP) and 322-3 (BN) are turned on, and switches 322-2 (AN) and 322-4 (BP) are turned off.

[0073] Next, by turning switch 322-1 (AP) off and switch 322-2 (AN) on, the system can transition from state 520 (positive state with switch configuration 410) to state 530 (zero-1 state with switch configuration 430 as shown in Figure 4C).

[0074] Next, by turning off switch 322-3 (BN) and turning on switch 322-4 (BP), the system can transition from state 530 (a zero-1 state with switch configuration 430) to state 540. For example, state 540 can be called a negative state and can be generated by configuring an H-bridge circuit in the negative switch configuration 420 shown in Figure 4B. In the negative switch configuration 420, switches 322-2 (AN) and 322-4 (BP) are turned on, and switches 322-1 (AP) and 322-3 (BN) are turned off. By sequentially repeating states 510 to 540, modulation scheme 1 can be continuously generated.

[0075] As further shown in Figure 5B, a waveform similar to that shown in Figure 5A can be generated using modulation scheme 2, for example, by controlling the switching configuration of the H-bridge circuit based on modulation scheme 2. In modulation scheme 2, state 510 can be generated by configuring an H-bridge in the zero-two switch configuration 440 shown in Figure 4D. In the zero-two switch configuration 440, switches 322-1 (AP) and 322-4 (BP) are turned on, and switches 322-2 (AN) and 322-3 (BN) are turned off.

[0076] Next, by turning off switch 322-4 (BP) and turning on switch 322-3 (BN), the system can transition from state 510, which corresponds to switch configuration 440, to positive state 520, which corresponds to switch configuration 410. In state 520, the H-bridge circuit can be configured as positive switch configuration 410 in Figure 4A. In positive switch configuration 410, switches 322-1 (AP) and 322-3 (BN) are turned on, and switches 322-2 (AN) and 322-4 (BP) are turned off.

[0077] Next, by turning switch 322-3(BN) off and switch 322-4(BP) on, the system can transition from state 520 (positive state with switch configuration 410) to state 530 (zero-2 state with switch configuration 440 in Figure 4D).

[0078] Next, by turning off switch 322-1 (AP) and turning on switch 322-2 (AN), the system can transition from state 530 (zero-2 state with switch configuration 440) to state 540, i.e., the negative state. The negative state can be achieved by configuring an H-bridge in the negative switch configuration 420 shown in Figure 4B. In the negative switch configuration 420, switches 322-2 (AN) and 322-4 (BP) are turned on, and switches 322-1 (AP) and 322-3 (BN) are turned off. By sequentially repeating states 510 to 540 corresponding to modulation scheme 2, modulation scheme 2 can be continuously generated.

[0079] In some scenarios, one or more switches in an H-bridge circuit may reach higher temperatures than other switches during their operation (e.g., hot spots) based on the switching configurations of modulation schemes 1 and 2. For example, modulation scheme 1 can cause hot spot temperatures in switches 322-2(AN) and 322-3(BN). For instance, switch 322-2(AN) is turned on during states 510, 530, and 540, and switch 322-3(BN) is turned on during states 510, 520, and 530. This can cause the temperatures of switches 322-2(AN) and 322-3(BN) to be higher than those of the other switches. Additionally, switches 322-2(AN) and 322-3(BN) can dissipate more power compared to the other switches. Furthermore, in modulation scheme 2, switch 322-1(AP) is turned on during states 510, 520, and 530, and switch 322-4(BP) is turned on during states 510, 530, and 540. Therefore, the temperatures of switches 322-1(AP) and 322-4(BP) can be higher than those of the other switches, and switches 322-1(AP) and 322-4(BP) can dissipate more power compared to the other switches. These configurations for controlling an H-bridge circuit may have technical limitations related to the hotspot temperature on one or more switches in particular.

[0080] Example H-bridge switch configuration Figures 6A and 6B show two examples of modulation schemes, modulation scheme 3 and modulation scheme 4. Modulation schemes 3 and 4 can be used as H-bridge circuits to control the waveform. Modulation schemes 3 and 4 can be applied to H-bridge circuits implemented in grounding pads or vehicle pads. For example, the H-bridge circuits described with reference to Figures 6A and 6B can be any suitable H-bridge circuit in a wireless charging system (e.g., any of the H-bridge circuits 202A to 202D or 208A to 208D in Figures 2A to 2D). The switching configuration of the H-bridge circuit is described with reference to Figures 4A to 4D (configurations 410 to 440).

[0081] Compared to modulation schemes 1 and 2 in Figures 5A and 5B, modulation schemes 3 and 4 in Figures 6A and 6B can provide thermal equilibrium (and power dissipation equilibrium) between switches 322-1 and 322-4. Such thermal equilibrium can be achieved by balancing the conduction losses between the switches, and the switching current levels between switches 322-1 and 322-4 can have different current levels. For example, in Figures 5A and 5B, each cycle of modulation scheme 1 (e.g., states 510 to 540) generates hot spot temperatures on switches 322-2 (AN) and 322-3 (BN). As another example, each cycle of modulation scheme 2 (e.g., states 510 to 540) generates hot spot temperatures on switches 322-1 (AP) and 322-4 (BP). The modulation schemes in Figures 6A and 6B can provide thermal equilibrium (and balanced power dissipation) between switches 322-1 to 322-4 by, for example, balancing the on-time of each switch in the H-bridge circuit. Therefore, power consumption between switches can be balanced, and the hotspot temperature can be significantly reduced. For example, the hotspot temperature corresponding to modulation schemes 3 and 4 can result in a temperature reduction of more than 10 degrees Celsius on the hotspot compared to modulation schemes 1 and 2. In some examples, modulation schemes 3 and 4 can even provide a temperature reduction of more than 10 degrees Celsius on the hotspot compared to when no modulation scheme is applied.

[0082] Figure 6A shows an example of a conceptual operating waveform applicable to H-bridge circuits 202A-202D (shown in Figures 2A-2D) or 208A-208D (shown in Figures 2A-2D). For convenience of explanation, the output voltage and current waveforms of the H-bridge circuit implemented on the grounding pad are denoted as V1 and I1, respectively. The output voltage and current waveforms of the H-bridge circuit implemented on the vehicle pad are denoted as V2 and I2, respectively.

[0083] The modulated waveform can be generated using modulation schemes 3 and 4, as described in Figure 6B. Each of the modulation schemes 3 and 4 can generate the same modulated waveform, as shown in Figure 6A. Modulation scheme 4 has different zero stages immediately following the positive and negative states compared to modulation scheme 3. In some embodiments, modulation schemes 3 and 4 can be used alternately and sequentially during the charging operation of the ground pad or vehicle pad. In some embodiments, multiple cycles of modulation scheme 3 can be used, followed by multiple cycles of modulation scheme 4 during the charging operation of the ground pad or vehicle pad.

[0084] Figure 6B maps the states of the H-bridge circuit to modulation schemes 3 and 4. As shown in Figure 6B, each of modulation schemes 3 and 4 generates a periodic waveform having four different states 610 to 640. As shown in Figure 6B, states 610, 620, 630, and 640 can be called zero, positive, zero, and negative states, respectively. In some embodiments, modulation schemes 3 and 4 can be formed with various switch configurations corresponding to each state.

[0085] In modulation scheme 3, state 610 corresponds to the configuration of the H-bridge circuit in the zero-one switch configuration 430 in Figure 4C. In the zero-one configuration 430, switches 322-2 (AN) and 322-3 (BN) are turned on, and switches 322-1 (AP) and 322-4 (BP) are turned off.

[0086] Next, the system can transition from state 610 to state 620 by turning off switch 322-2 (AN) and turning on switch 322-1 (AP). State 620 can be called the positive state and can be achieved by configuring an H-bridge circuit in the positive switch configuration 410 shown in Figure 4A. In the positive switch configuration 410, switches 322-1 (AP) and 322-3 (BN) are turned on, and switches 322-2 (AN) and 322-4 (BP) are turned off.

[0087] Next, by turning off switch 322-3(BN) and turning on switch 322-4(BP), the system can transition from state 620 (positive state) to state 630, which corresponds to the zero-two switch configuration 440 in Figure 4D. In the zero-two switch configuration 440, switches 322-1(AP) and 322-4(BP) are turned on, and switches 322-2(AN) and 322-3(BN) are turned off.

[0088] Next, by turning off switch 322-1 (AP) and turning on switch 322-2 (AN), the system can transition from state 630 (zero-2 state) to negative state 640, which is implemented by the switch configuration 420 in Figure 4B. In switch configuration 420, switches 322-2 (AN) and 322-4 (BP) are turned on, and switches 322-1 (AP) and 322-3 (BN) are turned off. For specific applications, the modulation scheme 3 can be continuously generated by sequentially repeating states 610 to 640.

[0089] As further shown in Figure 6B, by using modulation scheme 4, for example, by controlling the switching configuration of the H-bridge circuit based on modulation scheme 4, a waveform similar to that shown in Figure 6A can be generated. In modulation scheme 4, state 610 can be generated by configuring an H-bridge in the zero-two switch configuration 440 of Figure 4D. Next, by turning off switch 322-4 (BP) and turning on switch 322-3 (BN), it is possible to transition from state 610 to state 620, which can be achieved by the positive switch configuration 410 of Figure 4A. Next, by turning off switch 322-1 (AP) and turning on switch 322-2 (AN), it is possible to transition from state 620 (positive state) to the zero-one switch configuration 430 of Figure 4C. Next, by turning off switch 322-3 (BN) and turning on switch 322-4 (BP), it is possible to transition from state 630 (zero-one switch configuration 430) to state 640, which is the negative switch configuration 420 of Figure 4B. For specific applications, the modulation scheme 4 can be continuously generated by sequentially repeating states 610 to 640. The switch control circuit 326 can control the H-bridge circuit using one or more cycles of modulation scheme 3 followed by one or more cycles of modulation scheme 4.

[0090] In some embodiments, as shown in Figures 6A and 6B, modulation schemes 3 and 4 can balance the on-time of switches 322-1 to 322-4 while they are conducting. For example, each switch can be turned on twice during one cycle of the modulated waveform. Thus, the temperature of each switch can be balanced without significantly increasing the hotspot temperature on one or more switches.

[0091] As further shown in Figures 6A and 6B, the transition between state 610 and state 620 can occur when the current i1 is at current level Isw 2. Similarly, the transition between state 620 and state 630 can occur when the current i1 is at current level Isw 1. Furthermore, the transition between state 630 and state 640 can occur when the current i1 is at current level Isw 2. As shown in modulation scheme 3 in Figure 6B, switch 322-1 can be turned on at current level Isw 2 (during the transition between state 610 and state 620), switch 322-3 can be turned on at current level Isw 1 (during the transition between state 620 and state 630), and switch 322-2 can be turned on at current level Isw 2 (during the transition between state 630 and state 640). Since the current level Isw 1 is higher than the current level Isw 2, the power consumption in switch 322-3 (e.g., the switching in the transition between states 620 and 630 by turning switch 322-3 off and switch 322-4 on) may be different (e.g., higher) than other transitions (e.g., the transition between states 610 and 620 and between states 630 and 640). Therefore, the temperatures of switches 322-3 and 322-4 may be different (e.g., higher) than the temperatures of switches 322-1 and 322-2.

[0092] As further shown in modulation scheme 4 in Figure 6B, switches 322-4 can be turned off at current level Isw 2 (during the transition between states 610 and 620), and switches 322-1 can be turned on and 322-2 off at current level Isw 1 (during the transition between states 620 and 630). Switch 322-3 can also be turned off at current level Isw 2 (during the transition between states 630 and 640). Since current level Isw 1 is higher than current level Isw 2, switches turned off at Isw 1 (e.g., switches 322-1 and 322-2) should have higher switching losses. Therefore, the temperatures of switches 322-1 and 322-2 can be higher than those of switches 322-3 and 322-4. By alternating between modulation schemes 3 and 4, further temperature balancing can be achieved between switches 322-1 to 322-4.

[0093] This disclosure does not limit the order in which modulation schemes 3 and 4 are applied, and modulation schemes 3 and 4 can be applied in any order based on the specific application. In some embodiments, modulation scheme 3 may account for 0% to 100% of the wireless charging cycle. In other embodiments, modulation scheme 4 may account for 0% to 100% of the wireless charging cycle. Figure 6B shows that the duration of states 620 and 640 is longer than that of states 610 and 630, but in other embodiments, the duration of states 610 and 630 may be longer than that of states 620 and 640.

[0094] Exemplary waveform with alternating modulation As described above, modulation schemes 3 and 4 (shown in Figures 6A to 6B) can be applied alternately and sequentially. In some embodiments, the transition between modulation scheme 3 and modulation scheme 4 can be initiated during a positive state 620 or a negative state 640. Initiating the transition between modulation schemes during a positive state 620 or a negative state 640 can advantageously provide a smooth transition between modulation scheme 3 and modulation scheme 4.

[0095] Figure 7 shows exemplary waveforms related to switching of an H-bridge circuit having modulation schemes 3 and 4 with transitions in a zero-switch configuration. Figure 7 shows pulse-width modulation (PWM) counter signals 702A and 702B. As further shown in Figure 7, the modulated waveforms shown in Figure 6A can be generated by sequentially applying modulation scheme 4 and modulation scheme 3. For example, waveforms 704A, 704B, 706B, and 706A are applied to switches 322-1 (AP), 322-2 (AN), 322-3 (BN), and 322-4 (BP), respectively. By applying these waveforms to the H-bridge circuit 322, a modulated waveform 708 can be generated at the output of the H-bridge circuit. As shown in waveform 708, first, a switching configuration corresponding to modulation scheme 4 is applied (for example, by applying waveforms 704A, 704B, 706A, and 706B to the corresponding switches of the H-bridge circuit). For example, switching configurations corresponding to configurations 440, 410, 430, 420, and 440 (shown in Figures 4A to 4D) are applied sequentially, generating bridge output voltages corresponding to states 610, 620, 630, 640, and 610, respectively (shown in Figure 6B).

[0096] As further shown in Figure 7, a transition from modulation scheme 4 to modulation scheme 3 can be initiated during state 610 (e.g., the zero state). When the transition occurs at point 710, there is a relatively short period during which all switches (e.g., switches 322-1, 322-2, 322-3, and 322-4) are off, which may result in a positive voltage transient at the bridge output. Such a transition may be a non-smooth transition, and the transition may result in the application of additional voltage across the resonant tanks (e.g., resonant tanks 204A-204D included in the ground pad, or resonant tanks 206A-206D included in the vehicle pad), as shown during duration 720. Such additional voltage and current may drive undesirable overvoltages or currents into the resonant tanks, which may result in shortening the lifespan of the electrical components and / or causing damage to them.

[0097] Figure 8 shows waveforms related to switching in an H-bridge circuit with modulation schemes 3 and 4 with transitions in a non-zero-switch configuration. As shown in Figure 8, the modulation scheme shown in waveform 808 can produce a smooth transition between modulation scheme 4 and modulation scheme 3. This smooth transition may not introduce additional voltage and current drive into the resonant tank.

[0098] Figure 8 shows the PWM counter signals 802A and 802B. As further shown in Figure 8, the modulated waveform shown in Figure 6A can be generated by sequentially applying modulation scheme 4 and modulation scheme 3. For example, waveforms 804A, 804B, 806B, and 806A are applied to switches 322-1 (AP), 322-2 (AN), 322-3 (BN), and 322-4 (BP), respectively. Waveforms 804A, 804B, 806B, and 806A can represent signals generated by the switch control circuit 326 for controlling switches 322-1 (AP), 322-2 (AN), 322-3 (BN), and 322-4 (BP). By applying these waveforms to the H-bridge circuit 322, a modulated waveform 808 can be generated at the output of the H-bridge circuit. As shown in waveform 808, switching configurations corresponding to configurations 440, 410, 430, 420, 440, and 510 (shown in Figures 4A to 4D) are applied sequentially, generating bridge output voltages corresponding to states 610, 620, 630, 640, 610, and 620, respectively. As further shown in Figure 8, a transition to modulation scheme 3 (from modulation scheme 4) can be initiated during state 620 (e.g., a non-zero state). As further shown in Figure 8, the transition to modulation scheme 3 (from modulation scheme 4) can occur after a zero state (e.g., 610 or 630). Therefore, after the transition at point 810, a positive state (e.g., during a duration of 820 corresponding to configuration 410 in Figures 5A to 5C) may follow the zero state.

[0099] In some embodiments, a smooth transition at point 810 can be generated by delaying the application of modulation scheme 3 until the zero state of modulation scheme 4 is completed. As a result of the delay, the application of modulation scheme 3 can achieve a smooth transition at point 810 by avoiding the driving of overvoltages and overcurrents to the resonant tank.

[0100] Exemplary scenario for managing switching configuration control logic As described above, the switch control circuit 326 can control the switches of the H-bridge circuit to generate various modulation schemes 1 to 4. In some embodiments, the switch control circuit 326 can configure the H-bridge circuit into one or more sequences of switch configurations based on the modulation scheme by utilizing various control logics. For example, a processor or any other suitable circuit can implement the switch control circuit 326 to process various inputs and / or data to determine how to enable smooth transitions such as transitions between modulation schemes (e.g., transitions between modulation scheme 3 and modulation scheme 4), the frequency of transitions during wireless charging, and the transitions shown in Figure 8. In some examples, the switch control circuit 326 can control the switches based on the results of monitoring one or more operating parameters of the ground and / or vehicle pad, such as operating temperature and power level.

[0101] Figure 9 shows an exemplary embodiment of a switch control circuit 326 connected to an H-bridge circuit 322. In some embodiments, the switch control circuit 326 can be implemented on the grounding pad and control switch of the H-bridge circuit 322 to implement a switch configuration for one or more modulation schemes, such as one or more of modulation schemes 1 to 4. In some embodiments, the switch control circuit 326 can be implemented on the vehicle pad to control the switch of the H-bridge circuit 322 by alternately switching between modulation scheme 3 and modulation scheme 4.

[0102] As shown in Figure 9, the switch control circuit 326 may include a main processing circuit 902 and a gate driver 904. The main processing circuit 902 may include a processor and memory for processing various inputs and / or data to determine transitions between modulation schemes (e.g., transitions between modulation scheme 3 and modulation scheme 4), the frequency of transitions during wireless charging, methods for enabling smooth transitions such as the transitions shown in Figure 8, or any suitable combination thereof. Any suitable processor and memory may be included in the main processing circuit 902. The gate driver 904 may be configured to drive one or more input signals to control the switches. In some examples, the gate driver 904 may include various components for generating the input power used to control each switch, and these components may include, for example, amplifiers, but are not limited to amplifiers.

[0103] In some operations of the switch control circuit 326, the switch control circuit 326 can determine whether to switch / transition between modulation scheme 1 and modulation scheme 2, between modulation scheme 3 and modulation scheme 4, or between modulation scheme 1, modulation scheme 2, modulation scheme 3, and modulation scheme 4. The switch control circuit 326 can determine how often to switch between these modulation patterns. The switch control circuit 326 can determine transitions between modulation schemes based on the non-equilibrium temperature and its effects. The non-equilibrium temperature can be derived from one or more operating points, including the battery voltage level, ground pad DC voltage level, coupling coefficient, power level, tank currents of the ground pad and vehicle pad, inductance estimates of the ground pad and vehicle pad, and / or temperature from temperature sensors of the components.

[0104] The main processing circuit 902 can be called a controller. In some embodiments, the main processing circuit 902 can be configured to perform various logic, such as logic for determining one or more of the following: whether to perform a transition, the frequency of the transition (e.g., the number of transitions), or a mechanism to enable a smooth transition (e.g., delaying the transition so that it occurs in a non-zero state). For example, the controller can determine whether to switch / transition between modulation schemes 1-2 or modulation schemes 3-4 or modulation schemes 1, 2, 3, and 4 (e.g., the modulation schemes shown in Figures 5A-5B and 6A and 6B), and how often to switch between these modulation schemes. The decision can be based on one or more of the following: battery voltage level, wall box voltage level, coupling coefficient, power level, tank currents of the ground pad and vehicle pad, estimated inductances of the ground pad and / or vehicle pad, or non-equilibrium temperature and its effects, which can be derived from the operating point, including temperature from temperature sensors of the components.

[0105] In various embodiments, as disclosed herein, the switch control circuit 326 can be configured to manage the switching configuration to produce a smooth transition during the transition between modulation scheme 4 and modulation scheme 3. Figure 8 shows a modulated waveform 808 with a smooth transition between modulation scheme 4 and modulation scheme 3. For example, the switch control circuit 326 can be configured to switch (e.g., transition) modulation scheme 4 to modulation scheme 3 after a zero state (e.g., 610 or 630). Thus, a positive state (corresponding to configuration 410 in Figures 5A-5C) may be followed by a zero state after point 810 (e.g., the transition point). In some embodiments, the switch control circuit 326 can delay the application of modulation scheme 3 until the zero state of modulation scheme 4 is complete. As a result of the delay, the application of modulation scheme 3 can make a smooth transition at point 810 by avoiding overvoltage and overcurrent driving to the resonant tank.

[0106] The foregoing disclosure is not intended to limit this disclosure to the exact form or specific field of use disclosed. Therefore, various alternative embodiments and / or modifications to this disclosure, whether expressly described or implied herein, are possible in light of this disclosure. While embodiments of this disclosure have been described in this manner, those skilled in the art will recognize that modifications in form and detail can be made without departing from the scope of this disclosure. Therefore, this disclosure is limited solely by the claims.

[0107] It should be understood that not all objectives or benefits will necessarily be achieved by following any specific example described herein. Therefore, for example, a person skilled in the art will recognize that some examples may be manipulated to achieve or optimize one benefit or set of benefits taught herein, without necessarily achieving other objectives or benefits that may be taught or suggested herein.

[0108] All processes described herein can be fully automated by being implemented in software code modules executed by a computing system including a computer or processor. The code modules may be stored in any type of non-temporary computer-readable medium or other computer storage device. Some or all of the methods may be implemented in dedicated computer hardware.

[0109] Many other variations not described herein will be apparent from this disclosure. For example, depending on the embodiment, any particular operation, event, or function of any of the algorithms described herein may be executed in a different order, and may be added, merged, or completely excluded (e.g., not all described actions or events are necessary for the implementation of the algorithm). Furthermore, in some examples, the operations or events may be executed not sequentially, but concurrently, for example, through multithreading, interrupt handling, or via multiple processors or processor cores, or on other parallel architectures. In addition, different tasks or processes may be executed by different machines and / or computing systems that can work together.

[0110] The various exemplary logic blocks and modules described in relation to the embodiments disclosed herein may be implemented or executed by machines such as processing units or processors, digital signal processors ("DSPs"), application-specific integrated circuits ("ASICs"), field-programmable gate arrays ("FPGAs") or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. The processor may be a microprocessor, but in alternative examples, the processor may be a controller, microcontroller, or state machine, or a combination thereof. The processor may include electrical circuits for processing computer-executable instructions. In some embodiments, the processor includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, a microprocessor combined with a DSP core, or any other such configuration. Although this specification primarily describes digital technologies, the processor may also include primarily analog components. Computing environments can include, but are not limited to, any type of computer system based on a microprocessor, mainframe computer, digital signal processor, portable computing device, device controller, or in-device computing engine, to name a few.

[0111] Elements of methods, processes, routines, or algorithms described in relation to embodiments disclosed herein can be directly embodied in hardware, software modules executed by a processor device, or a combination of the two. Software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of non-temporary computer-readable storage medium. Exemplary storage media can be coupled to a processor device so that the processor device can read information from and write information to the storage media. Alternatively, the storage media may be integrated into the processor device. The processor device and storage media can reside within an ASIC. The ASIC can reside within a user terminal. Alternatively, the processor device and storage media can reside as separate components within a user terminal.

[0112] Processes described herein or shown in the figures of this disclosure can be initiated on demand when started by a user or system administrator in response to an event such as a predetermined or dynamically determined schedule, or in response to any other event. Once such a process is initiated, a set of executable program instructions stored in one or more non-temporary computer-readable media (e.g., hard drives, flash memory, removable media) can be loaded into the memory (e.g., RAM) of a server or other computing device. The executable instructions may then be executed by the hardware-based computer processor of the computing device. In some embodiments, such a process or part thereof can be implemented in series or in parallel on multiple computing devices and / or multiple processors.

[0113] In particular, conditional language such as “can,” “could,” “might,” or “may” is generally understood in context to convey that some examples include certain features, elements, and / or processes, while others do not, unless otherwise specified. Thus, such conditional language is not generally intended to imply that the features, elements, and / or processes are in some way for the examples, or that these examples necessarily involve logic for determining whether these features, elements, and / or processes should be included in or performed in any particular example, with or without user input or prompting.

[0114] Disjunctive language, such as the phrase "at least one of X, Y, or Z," is generally understood in its context to indicate that an item, term, etc., can be X, Y, Z, or any combination thereof (e.g., X, Y, and / or Z), unless otherwise specified. Therefore, such disjunctive language should not, in general, imply that several examples require at least one X, at least one Y, or at least one Z to exist, respectively.

[0115] Any process description, element, or block in the flowcharts described herein and / or shown in the accompanying drawings should be understood as potentially representing a module, segment, or portion of code containing executable instructions for performing a particular logical function or element in the process. The examples described herein include alternative examples in which, depending on the function included, elements or functions may be omitted or executed in a different order than those shown or described, including substantially simultaneously or in reverse order, as will be understood by those skilled in the art.

[0116] It should be emphasized that many variations and modifications can be made to the above examples, and that these elements should be understood to be found in other acceptable examples. All such modifications and variations are intended to be included within the scope of this disclosure.

[0117] Any process description, element, or block in the flowcharts described herein and / or shown in the accompanying drawings should be understood as potentially representing a module, segment, or portion of code containing executable instructions for performing a particular logical function or element in the process. The examples described herein include implementations in which, as understood by those skilled in the art, elements or functions may be omitted or executed in a different order than those shown or described, including substantially simultaneously or in reverse order, depending on the function included.

[0118] Unless otherwise specified, articles such as "a" or "an" should generally be interpreted as including one or more of the listed items. Therefore, phrases such as "devices configured as" are intended to include one or more of the enumerated devices. Such one or more enumerated devices can also be collectively configured to perform the stated enumeration. For example, "processors configured to perform enumerations A, B, and C" could include a first processor configured to perform enumeration A, working in conjunction with a second processor configured to perform enumerations B and C.

Claims

1. A method of wireless power transmission, A step of controlling the H-bridge circuit of a grounding pad using a first modulation that constitutes an H-bridge, wherein the first modulation includes two non-zero switch configurations and two different zero switch configurations, and the two non-zero switch configurations include a positive switch configuration and a negative switch configuration, A step of transitioning the control of the H-bridge circuit from the first modulation to the second modulation, wherein the second modulation includes the two non-zero switch configurations and the two different zero switch configurations in a different order than the first modulation. The steps include: performing wireless power transmission from the grounding pad to the vehicle's vehicle pad using the H-bridge circuit; Methods that include...

2. The method according to claim 1, wherein the transition control of the H-bridge circuit from the first modulation to the second modulation occurs in time between one of the two non-zero switch configurations.

3. The method according to claim 1, wherein the first modulation controls the H-bridge circuit in a sequence in which each transition between switching configurations related to the sequence includes turning one switch on and turning one switch off.

4. The method according to claim 1, wherein both the first modulation and the second modulation correspond to providing the same output voltage waveform from the H-bridge circuit.

5. The method according to claim 1, wherein the first modulation includes operating the H-bridge circuit for a longer or shorter duration in the two non-zero-switch configurations than in the two different zero-switch configurations.

6. The method according to claim 1, wherein the first modulation controls the H-bridge circuit in a first sequence in which the positive switch configuration follows a first switch configuration from the two different zero switch configurations, and the second modulation controls the H-bridge circuit in a second sequence in which the positive switch configuration follows a second switch configuration from the two different zero switch configurations.

7. The method according to claim 1, wherein the first modulation controls the H-bridge circuit in a first sequence in which a second zero-switch configuration of the two different zero-switch configurations follows the positive-switch configuration, and the second modulation controls the H-bridge circuit in a second sequence in which a first zero-switch configuration of the two different zero-switch configurations follows the positive-switch configuration.

8. The method according to claim 1, wherein the H-bridge circuit is controlled by the first modulation for at least 50% of the wireless charging cycle.

9. The method according to claim 1, further comprising the step of transitioning the control of the H-bridge circuit from the second modulation to the third modulation, wherein the third modulation includes the two non-zero-switch configurations and only the first switch configuration of the two different zero-switch configurations.

10. The method according to claim 9, further comprising the step of transitioning the control of the H-bridge circuit from the second modulation to the fourth modulation, wherein the fourth modulation includes the two non-zero-switch configurations and only the second switch configuration of the two different zero-switch configurations.

11. The method according to claim 1, further comprising the step of determining, at least in part, on a temperature associated with the H-bridge circuit, that the H-bridge circuit should transition from the first modulation to the second modulation, wherein the control of the transition of the H-bridge circuit from the first modulation to the second modulation is performed in response to the determination.

12. The method according to claim 11, further comprising the step of determining the frequency of the transition control of the H-bridge circuit from the first modulation to the second modulation, at least partially based on the temperature associated with the H-bridge circuit.

13. A method of wireless power transmission, A step of controlling the switching circuit of a wireless charging pad with a first modulation that constitutes the switching circuit, wherein the first modulation includes two non-zero switch configurations and two different zero switch configurations, and the two non-zero switch configurations include a positive switch configuration and a negative switch configuration, The step of transitioning the control of the switching circuit from the first modulation to the second modulation, wherein the second modulation includes the two non-zero switch configurations and the two different zero switch configurations in a different order than the first modulation, The switching circuit receives a voltage related to wireless reception from another wireless charging pad.

14. The method according to claim 13, wherein the transition control of the switching circuit from the first modulation to the second modulation occurs in time between one of the two non-zero switch configurations.

15. It is a wireless charging pad, H-bridge circuit and, A resonant tank electrically connected to the H-bridge circuit, comprising a resonant tank equipped with a coil arranged for wireless power transmission, A switch control circuit configured to control the H-bridge circuit using both a first modulation and a second modulation is provided, A wireless charging pad wherein the first modulation comprises two non-zero switch configurations and two different zero switch configurations, and the second modulation comprises the two non-zero switch configurations and the two different zero switch configurations in a different order than the first modulation.

16. The wireless charging pad according to claim 15, wherein the wireless charging pad is a grounding pad.

17. The wireless charging pad according to claim 15, wherein the wireless charging pad is a vehicle pad.

18. The wireless charging pad according to claim 15, wherein the wireless charging pad is configured for wireless power transmission related to charging a vehicle's battery pack, and the battery pack has an operating voltage in the range of 200 volts to 800 volts.

19. The wireless charging pad according to claim 15, wherein controlling the H-bridge circuit includes transitioning the control of the H-bridge circuit from the first modulation to the second modulation.

20. The wireless charging pad according to claim 19, wherein the transition control of the H-bridge circuit from the first modulation to the second modulation occurs in time between one of the two non-zero switch configurations.

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