CA3236738A1 - Integrated wireless charging boost rectifier for electric vehicles - Google Patents

Abstract

An approach for wireless / contactless charging of electric vehicles is described where, instead of using additional components or electrical modules to conduct the charging, other components can be re-purposed to support the wireless charging. A specific control approach is also described that can be used to operate a dual-inverter drive as a DC-DC converter for regulating power into the batteries. This approach is beneficial as not only can there be less electronic components, but power delivery control can occur at the vehicle side.

Description

INTEGRATED WIRELESS CHARGING BOOST RECTIFIER FOR
ELECTRIC VEHICLES
CROSS-REFERENCE
[0001] This application is a non-provisional of, and claims all priority to, US Application No.
63/271,938, entitled "INTEGRATED WIRELESS CHARGING BOOST RECTIFIER FOR
ELECTRIC VEHICLES", filed 26-Oct-2021, incorporated herein by reference in its entirety.
FIELD

[0002] Embodiments of the present disclosure generally relate to the field of electric vehicle charging, and more specifically, embodiments relate to devices, systems and methods for integrated wireless charging boost rectifier for electric vehicles.
INTRODUCTION

[0003] Wireless charging for electric vehicles is desirable as a convenient alternative to wired charging. In particular, a driver of an electric vehicle would be able to park a vehicle and couple to a charging pad disposed in a parking spot such that the vehicle could then be wirelessly charged.

[0004] However, specific electronic components may be required for wireless charging so that wireless charging can be effected, for example, at high frequencies, and additional electronic components add extra weight, volume, and cost, decreasing the feasibility of electric vehicles as an alternative to internal combustion engine vehicles as the overall complexity and range is increased.

[0005] Another deficiency of existing wireless charging mechanisms is that the charging is controlled only from the transmitter side, requiring a communication from the vehicle to indicate charge status.

[0006] This dependency can lead to additional requirements of the transmitter and additional complexity of the transmitter as the transmitter would then need additional circuitry to regulate power delivery. A transmitter manufacturer may also be able to "lock in" electric vehicles to specific proprietary standards, which may also be undesirable.

SUMMARY

[0007] This application is directed to an approach for wireless /
contactless charging of electric vehicles where, instead of using additional components or electrical modules to conduct the charging, the existing components (e.g., dual inverter drive) of the vehicle are re-purposed to support the wireless charging. While examples describe uses with a dual inverter drive, not all embodiments necessarily utilize a dual inverter drive.

[0008] In particular, the dual inverter drive (e.g., coupled with a number of capacitors) can be utilized as a high frequency (e.g., 85 kHz) rectifier for wireless charging. A specific control approach is also described that can be used to operate the dual-inverter as a DC-DC converter for regulating power delivery to the batteries. This approach is beneficial as not only can there be less electronic components, but power delivery control (e.g., duty-cycle regulation) can occur at the vehicle side (as opposed to other approaches only at the power transmitter side).

[0009] In a first embodiment, an integrated on-board wireless charging device for charging an electric vehicle having a dual-inverter drivetrain during stand-still operation of the electric vehicle is proposed. The integrated on-board wireless charging device includes a controller circuit configured to control operation of at least four switches, Si, S2, S3, and S4, Si and S2 coupled to a first capacitor of a compensated wireless coil and stacked in series to a first traction stage of the dual inverter drive train having a first energy storage and S3 and S4 coupled to a second capacitor of the compensated wireless coil and stacked in series to a second traction stage of the dual inverter drivetrain having a second energy storage, Si and S3, when operated, respectively cause a bypass of the first energy storage and the second energy storage, and S2 and S4, when operated, respectively connect the first energy storage and the second energy storage. The controller circuit controls operation of the at least four switches to selectively control interconnection between a wireless power transmission system delivering an input voltage Vdc and the first traction stage and the second traction stage to establish at least one of two modes of operation: a first active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D when 0.5 < D < 1; a second active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D
when 0 < D <

0.5; wherein the at least four switches are utilized to establish conduction paths through the first traction stage and the second traction stage.

[0010] In some embodiments, a passive mode is provided for delivering maximum charging power where the first and second traction stage are not used as a DC/DC stage.

[0011] In some embodiments, the passive mode is utilized when regulation of power delivery by the integrated on-board wireless charging device is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil, and the at least two modes of operation are utilized when regulation of the power delivery is to be conducted on a receiver side by controlling operation of the compensated wireless coil.

[0012] In some embodiments, during the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating Si and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

[0013] In some embodiments, during the first active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC
current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC current;
and a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC
current.

[0014] In some embodiments, during the second active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating Si only that charges the first capacitor while also increasing capacitor voltages with a DC
current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a

15 conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC
current.
[0015] In some embodiments, the controller circuit is adapted for providing charge control on receiver side power electronics.

[0016] In some embodiments, the controller circuit is adapted for providing the charge control through establishing three control loops adapted to regulate an average current into the first energy storage and the second energy storage.

[0017] In some embodiments, the device is configured for interoperation with a conductive charging system, the conductive charging system including four relays, R1, R2, R3, and R4, and two capacitors, Cl, and C2.

[0018] In some embodiments, the four relays are adapted to conduct current in a receiver coil and are free of requirements to switch under load.

[0019] In a variant embodiment, an integrated on-board wireless charging device for charging an electric vehicle having a dual-inverter drivetrain during stand-still operation of the electric vehicle is proposed. The integrated on-board wireless charging device includes a controller circuit configured to control operation of at least four switches, Si, S2, S3, and S4, Si and S2 coupled to a first capacitor of a compensated wireless coil and stacked in series to a first traction stage of the dual inverter drive train having a first energy storage coupled to a first capacitor C1 and a compensated wireless coil and S3 and S4 coupled to a second energy storage coupled to a second capacitor C2 and the compensated wireless coil, of the compensated wireless coil and stacked in series to a second traction stage of the dual inverter drivetrain having a second energy storage, Si and S3, when operated, respectively cause a bypass of the first energy storage and the second energy storage, and S2 and S4, when operated, respectively connect the first energy storage and the second energy storage.

[0020] The controller circuit controls operation of the at least four switches to selectively control interconnection between of a wireless power transmission system delivering an input voltage Vdc to establish a passive mode of operation. In the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating Si and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

[0021] In some embodiments, the integrated on-board wireless charging device is configured to operate in the passive mode when the device is delivering maximum charging power.

[0022] In some embodiments, the integrated on-board wireless charging device is coupled to a dual inverter drive train or an external power source, and the integrated on-board wireless charging device is configured to operate in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

[0023] In some embodiments, the integrated on-board wireless charging device is configured to operate in the passive mode when regulation of power delivery by the integrated on-board wireless charging device is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil.

[0024] In some embodiments, the integrated on-board wireless charging device is configured to operate in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

[0025] In some embodiments, during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC
current.

[0026] In some embodiments, during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating Si only that charges the first capacitor while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC
current.

[0027] In some embodiments, during the active mode, one of two active modes are utilized:
a first active mode where the a first traction stage and the a second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D when 0.5 < D < 1; and a second active mode where the first traction stage and the second traction stage are used as a DC/DC
converter to regulate Vdc at a duty cycle D when 0 < D < 0.5.

[0028] In some embodiments, the integrated on-board wireless charging device is configured to operate in either the passive mode, the first active mode or the second active mode depending on a state of the duty cycle D, and the duty cycle D is controllable.

[0029] In some embodiments, the integrated on-board wireless charging device is configured to operate in a passive mode and the voltage Vdc is regulated by a converter.

[0030] In some embodiments, the duty cycle D is controllable.

[0031] Corresponding wireless charging methods and software / firmware program products (e.g., non-transitory computer / machine readable media storing machine interpretable instruction sets for execution by a processor to carry out any of the methods) are contemplated.
DESCRIPTION OF THE FIGURES

[0032] In the figures, embodiments are illustrated by way of example. It is to be expressly understood that the description and figures are only for the purpose of illustration and as an aid to understanding.

[0033] Embodiments will now be described, by way of example only, with reference to the attached figures, wherein in the figures:

[0034] FIG. 1 is an example block schematic diagram of a wireless charging solution.

[0035] FIG. 2 is an example block schematic diagram of a system for a wireless charging solution.

[0036] FIG. 3 is a block schematic diagram of a system for a connection of the wireless receiver coil to an existing drivetrain, according to some embodiments.

[0037] FIG. 4 is a block schematic diagram of a system for an integrated wireless charge that leverages a dual-inverter drivetrain, according to some embodiments.

[0038] FIG. 5 is a block schematic diagram of a system for an integrated wireless charger, based on the integrated single phase charger, according to some embodiments.

[0039] FIG. 6 is an example block schematic diagram of a system for a wireless power transmission system, according to some embodiments. A wireless power transmission system is a non-limiting example of a conductive charging system.

[0040] FIG. 7A is an example block schematic diagram of a circuit during passive operating mode of the conductive path during positive half cycle (/õ > 0). As noted herein, in some embodiments, the dual inverter is not required for this operating mode. For example, the switches and the capacitors of the circuit can be used to charge dual energy storage devices, in another variant embodiment.

[0041] FIG. 7B is an example block schematic diagram of a circuit during passive operating mode of the conductive path during negative half cycle (/õ < 0). As noted herein, in some embodiments, the dual inverter is not required for this operating mode. For example, the switches and the capacitors of the circuit can be used to charge dual energy storage devices, in another variant embodiment.

[0042] FIG. 8A is an example block schematic diagram of a circuit during active mode A
operation where 0.5 < D < 1, specifically of a conduction path during postive half cycle (/õ >
0).

[0043] FIG. 8B is an example block schematic diagram of a circuit during active mode A
operation where 0.5 <D < 1, specifically of a conduction path during negative half cycle (/õ <
0).

[0044] FIG. 9A is an example block schematic diagram of a circuit during active mode B
operation where 0 < D < 0.5, specifically of a conduction path during positive half cycle (/õ >
0).

[0045] FIG. 9B is an example block schematic diagram of a circuit during active mode B
operation where 0 < D < 0.5, specifically of a conduction path during negative half cycle (/õ <
0).

[0046] FIG. 10 is a plot of normalized charging power into the batteries (Pchg) versus dc-dc stage duty cycle (D).

[0047] FIG. 11 is an example block schematic diagram of a dc-dc stage implemented using the traction inverters and motor.

[0048] FIG. 12 is a plot of a normalized inductor current ripple as a function of the duty cycle (D).

[0049] FIG. 13A is a block schematic diagram of a control approach of an integrated charger, according to some embodiments.

[0050] FIG. 13B is a circuit diagram, according to some embodiments.

[0051] FIG. 14 is a schematic flowchart for the states of the wireless transmitter and the integrated charger.

[0052] FIG. 15 is an example of a simulation of a complete charging cycle, where Vb*_õ9 =
360V and the coils are well-aligned.

[0053] FIG. 16 is an example of a simulation of complete charging cycle, where irb _õ9 =
360V and the coils are misaligned.

[0054] FIG. 17 is a depiction of the experimental setup showing the system

[0055] FIG. 18 is a depiction of the dual inverter drive integrated charger, along with the EV
machine.

[0056] FIG. 19 is a depiction of a system performance operating in passive mode. The inherent charge balancing is also shown by setting Vbi= 350V while Vb2=315V.

[0057] FIG. 20 is a depiction of a system performance operating in active mode with D =
0.34.

[0058] FIG. 21 is a plot showing the experimentally measured charging power into the batteries ('N) versus the dc-dc duty cycle (D).

[0059] FIG. 22 is a depiction of a battery current step from 5A to 8A, with the battery currents offset.

[0060] FIG. 23 is a depiction of a set change in 6(0 from 0 to 0.1, showing the ability of the converter to set individual battery currents, at any speed, with no controller interaction with the CC/CV average controllers.

[0061] FIG. 24 is a plot of the overall system efficiency, measuring loss ('N) in three main operating modes (aligned (passive), aligned (active, D = 0.5), and misaligned (active, D =
0.337).

[0062] FIG. 25 is a block schematic of an example commercial implementation of the integrated charger, according to some embodiments.

[0063] FIG. 26 is a block schematic of another example commercial implementation of the integrated charger, according to some embodiments.
DETAILED DESCRIPTION

[0064] This application is directed to an approach for wireless /
contactless charging of electric vehicles where, instead of using additional components or electrical modules to conduct the charging, the existing components (e.g., dual inverter drive) of the vehicle are re-purposed to support the wireless charging. As noted herein, not all embodiments necessarily have a dual inverter drive. In a variant embodiment, the circuit topology can be used such that switches and the capacitors of the circuit can be used to charge dual energy storage devices. A number of different operating modes are proposed herein, including a passive .. mode and two active modes. The proposed circuit topology can include a proposed wireless connection that is a compensated wireless coil in conjunction with two capacitors and four switches, which can be coupled to a dual inverter drivetrain or a dual energy storage devices (e.g., dual batteries). In some embodiments, a system includes both the proposed wireless connection, and a dual inverter drivetrain or the dual energy storage devices.

[0065] The dual inverter drive (e.g., coupled with a number of capacitors) can be utilized as a high frequency (e.g., nominally at 85 kHz, but could vary, such as a range from 80-90 kHz) rectifier for wireless charging. Other frequencies are possible, for example, as standards change (e.g., 80-90 kHz may be selected due to other considerations such as avoiding interference with other types of signal propagation), and the proposed circuit of various embodiments can be adapted to different frequencies as well in view of device requirements.

[0066] Being able to re-purpose existing components is useful to reduce an overall weight, volume, cost, and complexity of the electric vehicle while still providing wireless / contactless charging. While some embodiments are directed to wireless charging of electric vehicles, there may be non-electric vehicle operation for controlling power delivery to other types of circuits that have dual-inverter topologies, such as multi-port converters for solar panels, among others. In these variations, the motor of the electric vehicle could be replaced with an inductor.

[0067] A control approach is also described that can be used to regulate power into storage devices, such as batteries. For example, a specific control approach can be used to operate the dual-inverter as a DC-DC converter for regulating power into the batteries. This approach is beneficial as not only can there be less electronic components, but power delivery control (e.g., duty-cycle regulation) can occur at the vehicle side (as opposed to other approaches at the power transmitter side). In an embodiment, an approach is directed to the reduced-component rectifier described. In a variant embodiment, the approach is directed to the reduced component rectifier that is also controlled to provide power regulation.

[0068] Integrated on-board charging has gained significant due to the potential cost and weight savings in the vehicle [1]-[5]. Integrated charging involves re-purposing the existing drivetrain components, namely the power electronics and motor, as part of the charging system. In doing so, this can eliminate additional power electronics and magnetics (and their associated cooling requirements, connectors, and enclosures) required for charging from an ac grid. Another advantage of integrated chargers are their high charging power. As integrated chargers use the high power traction power electronics and motor, they are capable of processing over 100 kW of power. Therefore, when used for charging, they allow higher charging currents, resulting in faster charging speeds.

[0069] Various integrated chargers have been proposed based on different drivetrain configurations. A solution proposed in [6] demonstrated ac charging from a single phase grid by connecting the grid through a diode bridge between the motor's neutral point and the negative dc terminal of the battery. In this case, the traction inverter was operated as a three-phase PFC boost converter.

[0070] Renault's commercially sold integrated charging solution involves using a current source converter front-end to interface the drivetrain to the grid [7], [8].
An topology based on the dual-inverter drive architecture was introduced in [9], where a silicon carbide (SiC) active front end (AFE) was added to allow bidirectional ac charging at up to 19.2kW.
Peak efficiencies of 97% were reported.

[0071] While conductive charging is the most common charging method today in most EVs, inductive/wireless charging has also been gaining popularity for its improved convenience and safety [10].

[0072] FIG. 1 is an example block schematic diagram of a wireless charging solution.
System 100 includes a battery device coupled to a receiver power electronics device is coupled to some communication embodiments and some compensation network embodiments. The receiver power electronics device is coupled, in some embodiments, to a transmitter power electronics device. The transmitter power electronics device is coupled in some embodiments to some communication embodiments and some compensation network embodiments.

[0073] While potentially not as efficient as conductive charging, some applications benefit greatly from wireless charging, such as transit vehicles, autonomous vehicles, as well as vehicles operating in harsh conditions [11]. Wireless charging can be more convenient and useful, especially in areas of limited real-estate, such as in city centers, or in situations where .. there is little time or labor available to connect devices for conductive charging (e.g., where turnaround time is short between scheduled vehicles). Transmissions efficiency has improved for wireless chargers, especially under mis-aligned cases [12]-[15]. In [15], the losses associated with transmitter-receiver coil misalignment were reduced by employing field-oriented control to direct the magnetic field toward the receiver.

[0074] However, wireless charging systems are usually very expensive and low power compared to even single-phase ac charging. That being said, advances have enabled high power wireless power transfer (20kW+) [16]. For example, in [17] a 50kW
wireless power transfer was demonstrated. Aside from the wireless coils, wireless power transfer also requires power electronics. Requiring power electronics means that the higher the power, the larger and more expensive are the required power electronics on-board the vehicle.

[0075] In some instances, cost and weight savings on-board the car are made by placing a passive, rectifying converter on-board the car, and having the transmitter power electronics perform the necessary charge control. In this approach, the controller feedback variables must be transmitted form the vehicle using a form of wireless communication in real time. This is a technical deficiency and can pose a challenge for the robustness and security of the vehicle/charger [18].

[0076] In order to eliminate the need for wireless communication of sensitive controller feedback signals, [19]-[23] have implemented the control on the receiver (on-board) side.
However, in all of these cases, the converters on-board the vehicle become significantly more complex and expensive, making it prohibitive to scale up the charging power.

[0077] The feasibility of an integrated wireless system is used in order to simultaneously address the high cost and low charging power of current wireless charging solutions.
Specifically, re-purposing existing components on the vehicle used for the drivetrain/charging (eg, magnetics such as the motor), is proposed as a potential approach to serve as part of the receiver-side power electronics in the car. This reduces the cost associated with needing discrete wireless charging power electronics, while enabling higher charging power.

[0078] The approach in [24] re-purposed the vehicle's on-board single-phase charger to perform the majority of the receiver side charge control. This can be a large cost savings, however it still requires a traditional on-board single phase ac charger and is limited to the power of that charger (usually around 6.6kVV).

[0079] FIG. 2 is an example block schematic diagram of a system for a wireless charging solution.

[0080] In [25], better integration was achieved by connecting the wireless receiver coil through a diode bridge between the neutral point and the negative dc terminal of the battery, as shown in FIG. 2. System 200 builds on the integrated single phase charger in [6].

[0081] However, this requires an additional diode bridge, and it still requires traditional transmitter side control. Furthermore, it requires that the drivetrain carry high frequency wireless charging currents, which will either substantially degrade efficiency, or require costly optimization of the drivetrain to limit high frequency losses.

[0082] This approach proposes an integrated wireless charger, as shown in FIG.
3.

[0083] FIG. 3 is a block schematic diagram of a system that can be used, for example, for a connection of the wireless receiver coil to an existing drivetrain detailed in [9], according to some embodiments. System 300 comprises several blocks; a dual inverter drive 302, comprises of two traction inverters 304, two batteries (306 and 308), and an open winding machine 310, as well as the connection 312 to the compensated wireless receiver coil 314 for receiving power delivery from a corresponding transmitter coil. As noted herein, while in FIG.
3 a dual inverter drivetrain is shown, it is important to note that in some embodiments, the proposed connection does not necessarily need to be connected to a dual inverter or traction .. inverters, but can be used instead to couple to different circuits, such as a dual energy storage device (e.g., dual batteries).

[0084] Compensation is added to the natural impedance of the coils themselves, where at high frequencies, the coil itself will behave as a high impedance device, and the compensation (e.g., by adding capacitors; a capacitor, an inductor, and a capacitor, a capacitor and an inductor) can cause cancellation of the impedance of the coil to increase an ease of driving a current through the coil. The proposed system could operate without compensation of the receiver coil, but the system would encounter high impedances. The proposed connection (e.g., circuit) requires at least 2 small capacitors (316 and 318) as well as four switches (320, 322, 324, and 326). A detailed schematic is shown in FIG. 4.

[0085] FIG. 4 is a block schematic diagram of a system for an integrated wireless charge that leverages a dual-inverter drivetrain, according to some embodiments.

[0086] System 400 is comprised of a dual inverter drivetrain 402 coupled to a wireless connection 404. The dual inverter drivetrain 402 comprises of two inverters (406 and 408), a motor 410, as well as the connection 404 to the compensated wireless coil 412.
The proposed wireless connection comprises of two capacitors (414 and 416), as well as four switches (418, 420, 422, and 424).

[0087] Variations are possible and the components described are provided as a non-limiting, illustrative example. Switch 51, 418 and switch S2, 420, are stacked in series where the top of 51 and the bottom of S2 are connected across the battery, and the midpoint between 51 and S2 is connected to the wireless coil.

[0088] When 51 or S2 are operated, a current loop is established that, depending on the operating mode, may direct current into capacitor Cl or battery Bl, depending on the direction of energy flow. 51 and S2 can be switched on intentionally by applying a certain stimulus or they can commutate naturally with the flow of current. The frequency of the switching should be at least equal to the fundamental frequency of the wireless receiver coil current. 51 and S2 are operating so as to maintain a continuous flow of current from the wireless coil, but can be used to direct this flow of current into other components of the system, which can result in a different amount of power extracted from the wireless coil. 51 and S2 are never switched on together. An example of 51 switched on can be observed in FIG. 9A. An example of S2 switched on can be observed in FIG. 8B.

[0089] When S3 or S4 are operated, a current loop is established that, depending on the operating mode, may direct current into capacitor 02 or battery B2, depending on the direction of energy flow. S3 and S4 can be switched on intentionally by applying a certain stimulus or they can commutate naturally with the flow of current. The frequency of the switching should be at least equal to the fundamental frequency of the wireless receiver coil current. S3 and S4 are operating so as to maintain a continuous flow of current from the wireless coil, but can be used to direct this flow of current into other components of the system, which can result in a different amount of power extracted from the wireless coil. S3 and S4 are never switched on together. An example of S3 switched on can be observed in FIG. 8A. An example of S4 switched on can be observed in FIG. 9B.

[0090] The system 400 is shown as an example. Depending on a configuration (e.g., Active Mode B + Passive Mode Only), there may be less switches (e.g., only the switches required for a particular mode) required, and accordingly, the number of switches does not necessarily need to be four (e.g., switches shown that are never used for a particular mode can simply not .. be present). This occurs, for example, in example embodiments where the circuit is to be operated only active mode A, or only active mode B. If passive mode is to be incorporated in another embodiment (e.g., an ability to switch between passive mode and either (or both) of active modes A and B), then all four switches need to be present as all four switches are used in passive mode (see FIGS. 7A, 7B).

[0091] With respect to FIG. 4, the switches of the dual inverter drive (labelled Sal, etc.) can be operated in respect of a duty cycle D. The duty cycle D can be used to control the state of operation, for example, to swap between the passive mode of operation and/or the various active modes. In a first embodiment, the device is adapted to only operate in the passive mode. As noted above, the device operating in the passive mode does not always require the dual inverter drive or traction stages, and can instead, for example, charge dual batteries (e.g., the proposed wireless connection 404 can be coupled to other types of circuits).
In a second embodiment, the device is adapted to operate in the passive mode in addition to the first active mode. In a third embodiment, the device is adapted to operate in the passive mode in addition to the second active mode. In a fourth embodiment, the device is adapted to operate in the passive mode in addition to both the first active mode and the second active mode depending on the value of D. In a fifth embodiment, the device is adapted to operate in the passive mode in addition to both the first active mode and the second active mode and the mode is controlled by a switch or controller circuit in respect of the value of D.

[0092] This is effectively shown as a simplified representation in FIGS.
8A, 8B, 9A, 9B as virtual voltage source having the voltage equal to the duty cycle multiplied by the sum of the battery voltages: D (Vb1 + Vb2). As noted in these figures, it provides an additional current loop, which can serve to control the voltage across the rectifying capacitors.

[0093] The proposed wireless connection 404 could be mounted onto the dual inverter drivetrain 402, and can be applied, for example, on a retrofit of an electric vehicle to add wireless charging capabilities (e.g., adding an additional connection stage), or, in another example, onto a build of an all new electric vehicle as an integrated part of the drivetrain during manufacturing.

[0094] One embodiment of FIG. 4 is to use the dual inverter drive with integrated single phase ac charging, as proposed in [9].

[0095] If a dual inverter drive with integrated single phase ac charging, as proposed in [9]
is used, then the only additional components required will be two small capacitors (and some small relays for reconfiguration in order to maintain ac single phase ac charging capability).
This detailed charger schematic is shown in FIG. 5.

[0096] FIG. 5 is a block schematic diagram of a system for an integrated wireless charger, based on the integrated single phase charger, according to some embodiments.

[0097] System 500 comprises an integrated AC charger 502 utilizing a dual inverter drivetrain 504 coupled to a wireless connection 506, in some embodiment. In FIG. 5, the switches S1-S4 are not only useful for wireless charging, but can be used for other purposes, such as AC charging, bringing additional flexibility of utilization (e.g., further justifying inclusion of the switches). For AC charging, switches S1-S4 could be used as rectifier to connect an AC grid voltage to the dual inverter drive. For example, EVSE (electric vehicle supply equipment) would be a charging outlet for a connection for AC charging when connected to an AC grid.

[0098] System 500 saves cost of the power electronic components themselves, and also on the secondary requirements (e.g., liquid cooling plates, controller board, sensors, protection, battery contactors, enclosures, connectors, etc.). The direct connection to the drivetrain allows for the charging of both isolated batteries in the dual inverter drive from a single receiver coil.

[0099] Current wireless charging technologies are not designed to charge two isolated batteries which would make them incompatible with dual-inverter drivetrains.
Furthermore, the power electronics on the drivetrain can be leveraged to operate like a voltage doubler. This halves the voltage on the receiver coil, which in turn requires less flux from the transmitter coil.
This improves wireless transmission efficiency as it results in a lower current in the wireless transmitter coil, which is often physically large with many turns, and therefore subject to high ohmic losses.

[00100] II. Proposed Topology

[00101] A challenge with using an integrated charger as the power electronics for a wireless system is the high frequency requirements of the wireless power transfer. The standard for wireless power transfer recommends a frequency of 85khz. Other frequencies are possible.

[00102] From the drivetrain perspective, this high frequency current can create significant losses.

[00103] The large IGBT-based traction inverters cannot switch that fast due to the large device tail currents, and the motor magnetics may incur significant core loss.
The motor windings will also incur significant resistive losses, due to the skin effect phenomenon. As such, the drivetrain operating frequency must be kept low, and within the conventional operating range.

[00104] The two grid stage half bridges introduced in [9] can be implemented such that they can handle higher frequency currents. It is advantageous to use SiC devices for the grid stages for ac charging, as it is the main contributor of switching loss and determinate of the total harmonic distortion (THD) of the system [9].

[00105] It would be desireable to leverage these fast switching devices to rectify the high frequency wireless currents.

[00106] In order to allow this system to perform either ac charging as demonstrated in [9]
and wireless charging, relays R1-R4 must be closed during wireless charging, and opened during ac charging. In this case, the ac grid is only connected when the Electric Vehicle Supple Equipment (EVSE) is plugged into the vehicle and enabled (therefore no additional contactors are required on-board).

[00107] Relays R1-R4 and capacitors C1, C2 are the only additional components required to enable the integrated single-phase ac charger, to also serve as the power electronics for the .. wireless transmission system. As R1-R4 are only used for configuration of the circuit; they do not need to switch under load, and need only carry the current in the receiver coil. R1-R4 are distinct from switches S1-S4. For example, one could open all of R1-R4 for AC
charging, and one could close all of R1-R4 for wireless charging (effectively acting as a toggle between AC
and wireless charging).

[00108] Therefore, they are both small and inexpensive. If single phase ac charging is not desired, system 400 can be constructed, and the switches S1-S4 chosen appropriately.

[00109] Cl and C2 are capacitors (e.g., a film capacitor but could be implemented with other capacitor technologies), and could be rated appropriately (e.g., as they only carry a high frequency component, they can have a small capacitance value). An example capacitance value could be 10 uF. Other values, as non-limiting examples, could be larger values or smaller values (but too small could impart unwanted noise).

[00110] A. Wireless Coil Topology

[00111] FIG. 6 is an example block schematic diagram of a system for a wireless power transmission system, according to some embodiments. It is important to note that a wireless power transmission system is a non-limiting example of a conductive charging system, and that embodiments are contemplated for operation with various types of conductive charging systems. A compensated wireless coil is shown, which can be used for insertion into FIG. 7A, FIG. 7B, FIG. 8A, FIG. 8B, FIG. 9A, FIG. 9B. Variations are possible.

[00112] In system 600, the coils are rectangular coils (602 and 604) which have full series compensation on the primary 602 and secondary 604 side. The transmitter coil 606 is excited using a full bridge converter 608 that induces a voltage, over a gap 610, for example, 200 mm (other gaps are possible depending on a class of vehicle for example, as SUVs, trucks may have different ground clearances compared to sports cars), onto the receiver coil 606. Finally, the compensated receiver coil 612 is connected to the integrated wireless charger 614. The detailed parameters are described later in Table 2. The coils may have geometries other than rectangular coils as rectangular coils are used as a non-limiting example of a sample topology.
Other geometries could be circular, 3D coils, among others.

[00113] In this embodiment, it is expected that the charge control of the batteries is performed by the receiver side power electronics. In the analysis below, it is assumed that the wireless receiver is compensated such that it behaves as a current source.
Details regarding different compensation techniques can be found in [26].

[00114] The main relations / equations for the coils can be written as, [VZi Z [ Itx]

[00115] o ¨ ZM Z2 lirrx (1)

[00116] Where (neglecting parasitic resistances), = jcuLp ______________________________________________ jwCp (2) Z2 = jalLs 1 RL
(3) jwC,

[00117] Zm = jcuM
(4)

[00118] Resistance RL represents the equivalent load of the integrated charger. Choosing Cp and Cs. for full compensation yields, (5)

[00119] Z2 0 (6)

[00120] Combining (1) with (5) and (6) yield approximated equations for the currents in the transmitter and receiver, RLVtx x

[00121] M
(7) Vtx 1-rx

[00122] Zm (8)

[00123] To maximize efficiency of the wireless transmission system, it is desired to minimize the transmitter current [27]. Considering (7), it appears that RL must be reduced in order to reduce the transmitter current, /tx. In this case, using the fundamental frequency approach, RL is, 8 v2 _____________________________________________ dc 72po 4

[00124] RL
(9)

[00125] Where P0 is the desired charging power into the batteries, and Vd, is the rail-to-rail voltage shown in FIG. 5.

[00126] Connecting the wireless receiver to the mid-point of capacitors C1, C2 yields a voltage doubling effect, since the receiver only sees half of Vdc. This effectively reduces the resistance (RL) seen by the receiver coil by a factor of four, compared to a conventional full-bridge rectifier. This immediately means the transmitter current will be reduced by a factor of four, according to (7). In addition, Vdc can be reduced by operating traction inverter as a dc-dc converter. This is the main mechanism for controlling the power delivered to the batteries, from the wireless transfer system.

[00127] While the embodiment considers the use of this specific wireless transmission topology, it can be used with other systems. For example, if improved coil-to-coil efficiency under misalignment is desired, the described bipolar transmitter coil topology described in [28]
is used. The only requirement from the wireless transmission system is that the receiver must be compensated to behave as a current source and must have only two terminals.

[00128] B. Principle of Operation

[00129] The integrated charger will have three main modes of operation:
Passive mode, Active mode A and Active mode B.

[00130] 1) Passive Mode: Passive mode is enabled by not utilizing the traction inverters as a dc/dc stage. This mode of operation is used when the charging controllers request the maximum possible charging power, or when charge control will be done solely from the transmitter side. This is an advantageous operating mode, as it eliminates all the losses associated with the switching of the traction inverters and the motor. In some embodiments, this type of mode can also be employed without the traction inverter or motors present. A
schematic version of the passive mode, ignoring these components, is shown in FIG. 7A and FIG. 7B. While in a first embodiment, the circuit of FIG. 7A and FIG. 7B
include the traction stages and dual-inverter drivetrain, this is not necessarily present in all embodiments. In a second embodiment, the approach of FIG. 7A and FIG. 7B is directed to an energy storage device charger that charges, for example, two battery packs through the control of switches Si, S2, S3, and S4 and operating Capacitors Cl. Switches S1-S4 are shown as 720, 722, 724, and 726. The capacitors are shown as 728, and 730.

[00131] FIG. 7A is an example block schematic diagram 700A of a circuit during passive operating mode of the conductive path during positive half cycle (/õ > 0). 51 is on, S2 is off, S3 is on, and S4 is off. Essentially, C1 is being charged while battery 2 is being charged. C2 .. is being discharged.

[00132] FIG. 7B is an example block schematic diagram 700B of a circuit during passive operating mode of the conductive path during negative half cycle (/õ <0). 51 is off, S2 is on, S3 is off, S4 is on. Essentially, C2 is being charged while battery 1 is being charged. C1 is being discharged.

[00133] When the receiver current is positive (/õ > 0), conduction paths "A"
and "B" are both feasible conduction paths. Using KVL, the back-emf voltage required to forward bias the diode in each path can be determined as Vci Path "A"
vrx ¨
Vb2 VC2 Path "B"

[00134]
(10)

[00135] When the current is positive, the back-emf voltage will be

[00136] Vrx = Mi71,(Vci,Vb2 17c2) for Iõ > 0 (11)

[00137] When the current is negative (/õ.x < 0), the back-emf can be derived as { Vci ¨ Vbi Path "C"
Vrx (12) .. [00138]
VC2 Path "D"
[00139] Vrx = ¨Min(Vc2,Vbi ¨ Vc1) for I, <0 (13) [00140] The series connection of the two identical capacitors results in, [00141] VC1 ¨ VC2 ¨ Vdc/2 (14) [00142] Balancing/bleed resistors (with high ohmic value) are added to ensure this as well.
[00143] Using (14), equations (11), (13) can be re-written as, [00144] Vrx ¨ Mill(VdcI2,Vb2 Vdc12) for /rx > 0 (15) [00145] Vrx = ¨Min(Vdc12,Vbi ¨ Vdc12) for /, < 0 (16) [00146] During passive mode, the output voltage Vdc is defined by (11) and (13). During each cycle of the current, Vdc is when the terms in (11) and (13) are equal, Vdc/2 = Vb2 ¨ Vdc12 for /, > 0 (17) [00147] Vdc/2 = Vbi ¨ Vdc/2 for /,, <0 (18) Simplifying yields, Vb 2 if irx > 0 Vd¨

IVb1 if /rx < 0 (19) [00148]

[00149] Assuming the smoothing capacitors C1, C1 are large such that the ripple on Vdc is small at the frequency of the reciever current, this means that the steady state voltage will be, [00150] Vdc = Min(Vbi,Vb2) (20) [00151] Finally, the back-emf on the receiver coil can be determined by substituting (20) into (15) and (16) Min (Min (Vbi Vb2)/2. Vb2 ¨ = Vb2)/2) if /, > 0 [00152] ¨Min (31in( Vb1, 1/7b2)/2, Vi ¨ Min(Vbi, Vb2)/2) if /r, <0 (21) [00153] Vdc will be naturally set such that it ensures a symmetrical back-emf voltage during the positive and negative cycle of the receiver current. If it happens that the battery voltages are unequal, then the Vdc that is set enforces the conduction path that serves to charge the battery with the lower voltage. While this inherent capability is good, a specific value of Vdc cannot be chosen arbitrarily, thus there is no ability to control the charging rate of the batteries under passive operation.
[00154] 2) Active mode A: To control the charging rate of the batteries, the traction inverters are activated and used as a dc/dc converter to regulate the voltage Vdc. In order to create a simplified model for analysis, assume that three phases of the traction inverters are switched identically.
[00155] If the duty cycle of the dc-dc stage is defined as D, then the duty cycle applied to each switch can be defined as:
Sa,1 ¨ Sb,1 = Sc,1 = D
(22) [00156] Sa,2 = Sb,2 = Se,2 = D
[00157] Please note that equation (22) is not a mandatory requirement operate the dc-dc stage, rather a simplified example. Using (22), the traction inverter and motor is simplified down to a dc voltage source which sets the voltage Vdc as a function of the battery voltages and the duty cycle, [00158] Vdc = D (Vbi Vb2) (23) [00159] The operation of this dc-dc stage is expanded in detail in a further section.
[00160] Active mode A is defined when when 0.5 <D < 1. The simplified circuit is shown in FIG. 8A and FIG. 8B.
[00161] FIG. 8A is an example block schematic diagram 800A of a circuit during active mode A operation where 0.5 < D < 1, specifically of a conduction path during postive half cycle (/õ
>0).
[00162] FIG. 8B is an example block schematic diagram 800B of a circuit during active mode A operation where 0.5 < D < 1, specifically of a conduction path during negative half cycle (/õ
<0).
[00163] In active mode A, the conduction path for the positive and negative half cycle is traced as shown in 800A and 800B respectively. It is important to note that in a variant embodiment of FIG. 8A and FIG. 8B, active mode can be operated by providing an external power signal or source instead of necessarily using the dual inverter drive to provide D(Vb1 +
Vb2). Rather, D(Vb1 + Vb2) can be replaced by an external signal, for example, from an additional converter.
[00164] The conduction path during the positive half cycle is established by having S3 on, all others off (Si, S2, S4 off). 02 is discharging into B2. There are two things happening at the same time ¨ the wireless charging system is charging B2, and the dual inverter is creating conduction path E, which is serving to charge C1 and 02 from batteries B1 and B2 (e.g., at D(Vb1 + Vb2), to maintain a specific voltage on C1 and 02. The voltage is essentially used to control the charging power from the wireless coil. The wireless coil acts as a current source and the power out of the current source depends on the voltage across the current source, determined by the voltage across capacitors C1 and 02. This can be used to control the rate of flow. This mode of operation is particularly useful when used to keep the charging power within the required limits (e.g., to prevent overcharging of the batteries and/or to prevent pulling too much power from the wireless coil). The power delivery limits for the wireless coil can be based on limitations of the transmitter side, and in some embodiments, this limitation can be built into a controller or in another embodiment, the limitation can be transmitted to the controller.
[00165] The voltage source shown as D(Vb1 + Vb2) is a simplification of the contribution by the connection of the dual inverter (there is no actual voltage source).
[00166] If one refers to FIG. 4, the voltage source shown as D(Vb1 + Vb2) is actually from the connection across the motor windings 410 and the three phase switches of the dual inverter (for example, Sal, Sb,1, Sc,1, etc.).
[00167] The back-emf voltage on the reciever is determined to be Vb2 ¨ VC2 if /roc > 0 Vrx ¨
(24) Vci ¨ Vbi if irx <0 [00168]
[00169] The back-emf on the receiver is changed by changing the capacitor voltages 17c1, 17c2. Since these capacitors are related to Vdc, the voltages on these capacitors (and the back-emf voltage) is set by controlling the duty cycle D. Under this mode of operation the conduction path of the dc-dc stage (conduction loop "E" 800A) serves to increase the capacitor voltages with a dc current.
[00170] The back-emf can be written as a function of the duty as, Vb2 D(vbi+vb2) =
Trx > 0 Vrx D(Vbi+Vb2) 2 2 Vbi if _Trx <0 (25) [00171]
[00172] where, [00173] 0.5 < D < 1 (26) [00174] In this mode of operation, the batteries are charged directly with high frequency receiver current, as visible by the conduction loops "F" 800A and "H" 800B.
The dc-link capacitors still serve to significantly reduce any ripple current into the batteries.
[00175] 3) Active mode B: This operating mode is similar to the previous active mode, however it is defined for 0 < D < 0.5. The main distinction from active mode A
is that the conduction paths are different. The simplified model is derived as before and shown in FIG.
9A and FIG. 9B. In mode B, there are two conduction paths during the positive and negative half cycles, respectively.
[00176] A circuit does not necessarily need to be operable in both Active Modes A and B. In a first embodiment, the circuit operates only in Active Mode A. In a second embodiment, the circuit operates only in Active Mode B. In variations of the first and second embodiment, the circuit operates in Active Mode A or B in conjunction with the passive mode.
[00177] FIG. 9A is an example block schematic diagram 900A of a circuit during active mode B operation where 0 <D < 0.5, specifically of a conduction path during positive half cycle (/õ
> 0). During the positive half cycle, Cl is being charged by the wireless coil, and dual inverter D(Vb1+Vb2) is discharging Cl and charging Vb1+Vb2. Si is on, S2-4 are off.
[00178] FIG. 9B is an example block schematic diagram 900B of a circuit during active mode B operation where 0 < D < 0.5, specifically of a conduction path during negative half cycle (/õ
<0). During the negative half cycle, 02 is being charged by the wireless coil, and dual inverter D(Vb1+Vb2) is discharging 02 and charging Vb1+Vb2. S4 is on, 51, S2, S3 are off.
[00179] Active mode A and B are similar from a charging perspective, but Active mode B can be advantageous to Active mode A from a practical perspective. The voltage Vdc which shows up across the capacitors Cl and 02 goes between 0 and the average battery voltage, whereas in active mode A, it goes from average battery voltage all the way to the sum of the battery voltages.
[00180] If one operates in Active mode A, there is a higher voltage across the capacitors, which means one needs higher voltage rated capacitors which are more expensive and larger in size. If one operates in Active mode B, lower rated capacitors can be used.
For example, the system can be operated only using a combination of the passive mode and active mode B (not using active mode A at all).
[00181] Passive mode would be used for full power charging (e.g., uncontrolled), and active mode B would be used for controlled charging. Active mode B could be toggled on, for example, when there is risk of overcharging the batteries or the wireless transmitter has reached (or is nearing) its power delivery limits. To remain in Active mode B, one could control the duty cycle accordingly.
[00182] In active mode B, as the capacitor voltages 17c1, 17c2 are less than the corresponding battery voltages Vbi, Vb2, the high frequency coil current directly charges the capacitors. This can be seen from the conduction paths shown in 900A and 900B.
[00183] In this case, the back-emf is simply derived to be, Vc if /rx > 0 [00184] Vrx ¨
¨Vc2 if /rx <0 (27) [00185] As the receiver voltage is a function of the capacitor voltages, this means the back-emf can be controlled by the duty cycle of the dc-dc stage. Re-writing (27) as a function of the duty cycle, D(vbi+vb2) if /Tx > 0 Vrx D(Vbi+Vb2) if I 0 irx (28) [00186]
[00187] where, [00188] 0 < D < 0.5 (29) [00189] The back-emf is symmetrical during both cycles of the wireless ac current. This is .. advantageous because any mismatch in battery voltages will not introduce a dc offset in the back-emf seen by the wireless receiver coil. The charging power is controlled by adjusting the duty cycle of the dc-dc stage. This mode of operation will be used to control the charging rate of the batteries.
[00190] This mode of operation limits Vdc. to be at most equal to the average voltage of the two batteries Vbi, Vb2.
[00191] In turn, the voltage applied to the capacitors voltages 17c1, 17c2 will be smaller then active mode A, thereby reducing the size of the capacitors required.
[00192] FIG. 10 is a plot of normalized charging power into the batteries (Pchg) versus dc-dc stage duty cycle (D).
[00193] In plot 1000, at D = 0.5, the plot is symmetrical which indicates that both active mode A and active mode B are similar in terms of charging power control. Operating using either active mode is sufficient. Active mode B will be used in the system because it applies a symmetrical back-emf, as well as a lower overall voltage, Vdc.
[00194] It is important to note that one can operate purely in active mode A
or B and there does not necessarily need to be both present in an embodiment. In a variant embodiment, the duty cycle D can be controllable and used to switch between different modes, for example, being controlled by a controller circuit. This can be used in embodiments where the proposed wireless connection 404 operates alongside the dual inverter / traction inverter, where a combination of active and/or passive modes can be employed.
[00195] C) Traction Inverter dc-dc Stage [00196] The dual inverter drive has been shown to be able to operate as an integrated dc fast charger in [29], when connected to a voltage source (i.e., a dc grid), by regulating the current. In this embodiment, the traction inverters are operated such that they can connect to a current source (i.e., wireless receiver coil).
[00197] In this system, the traction inverter regulates the charging power by regulating the voltage (which appears across the wireless receiver).

[00198] A duty cycle D sent to switches Sat, Sc,1 and Sa,2, Sb,2, Sc,2 will result in an output voltage as determined by (23). For S1-S4, the operation is determined by the current in the transmitter coil (e.g., they could be diodes that switch at the frequency of voltage provided by the transmitter coil, and do not experience the duty cycle D).
[00199] Referring to FIG. 4, when gating signal (used to establish the duty cycle) is on, one would turn on switches Sal, Sb,1, and Sc,1, as well as Sa,2, Sb,2, and Sc2.
When the gating signal is off, then one would turn on the complementary switches, which are the switches that are not labelled.
[00200] An important constraint when using the motor during stand-still charging is that it must not produce any torque. In this case, if each phase receives the same duty cycle, the result is the same current in each phase. Based on Clark's transform, the same current in each phase equates to a zero sequence current, which cannot produce torque.
This type of operation has been exploited in integrated chargers, such as [30].
[00201] While the constraint to conduct only zero-sequence current in the machine means that the total duty cycle applied to each phase must be equal, there is a degree of freedom to choose the carrier phase shifts associated with each switch.
[00202] Following the analysis presented in [29], it is optimal to phase shift the carrier for each phase by 120 (phase-phase interleaving) and phase shift the carrier of all switches in the top traction inverter from the bottom traction inverter by 180 (top-bottom interleaving).
The net result of these phase shifts is that ripple on the motor windings is halved, while the ripple going into the battery is reduced by a factor of three.
[00203] FIG. 11 is an example block schematic diagram 1100 of a dc-dc stage implemented using the traction inverters and motor.
[00204] As with other multi-phase dc-dc converters, the total output current 'dc is the sum of the phase currents, [00205] idc = Isa Isb Isc (30) [00206] Therefore, by spacing out the ripple components of the three phase currents equally (120 ), the ripple seen on 'dc appears at three times the ripple frequency of the individual phases, or three times fsw. This ripple is important for sizing the rectifying capacitors, C1, and C2, as well as reducing losses in the battery.
[00207] Kirchoff's Voltage Law (KVL) is applied to understand the ripple across the motor inductance.
[00208] Neglecting parasitic resistances, and considering phase as an example, the voltage across the inductor is written as, [00209] vL(t) = Vde ¨ Vbi (Sal ¨ Vb2 (S
a2) (31) [00210] From (31), all the possible inductor voltages can be determined and are shown in TABLE 1.
TABLE 1 (De-De State Switching States) State Sal Sa2 VL
a 0 0 Vdc 0 1 Vdc Vb2 1 0 Vdc Vbl 1 1 Vdc Vbl Vb2 [00211] If the top and bottom gating signals Sat and Sa2 are shifted from each other by 180 , then states 'b' and 'c' are also utilized, which applies a reduced voltage across the inductor, compared to being just restricted to state 'd' and 'a'.
[00212] Using TABLE 1, the inductor ripple is determined for the system under two operating modes:

(Vde¨VOD if 0 < D <0.5 [00213]
AiL(t) = (vdfest)(1-D) if 0.5 < D < 1 (32) fsw L
[00214] where Ls is the inductance of the motor.
[00215] FIG. 12 is a plot of a normalized inductor current ripple as a function of the duty cycle (D).
[00216] According to (32) the inductor current ripple (iL(t)) changes as Vdc is changed.
Using active mode B (0 < D < 0.5) as an example, ripple decreases as the duty cycle approaches either 0 or 0.5 1200.
[00217] Operating at a duty cycle of zero implies zero power into the batteries, since Vdc =
0. A duty cycle of 0.5 implies maximum power into the batteries 1000.
[00218] This is important because the wireless transfer system can be optimized such that the dc/dc stage can operate at or near a duty cycle D= 0.5 during the majority of the charging period. This reduces losses in the machine, as well as the switches. Operating at D = 0.5 results in the same charging power as the passive mode of operation described herein, such that switching can be disabled on the dc-dc stage, further reducing losses.
[00219] Additional benefits can be obtained by not adhering to (22). For example, different duty cycles can be applied to each of the phases of the traction inverter in order to control the split of current within the motor phases.
[00220] 1) Standby Mode: While operating at a duty cycle of zero does not charge the batteries, it is still useful. This can be used to draw no power from the wireless receiver, effectively puts zero voltage across the wireless receiver by shorting it. One reason for doing this would be to stop charging the batteries by entering standby mode. This can be useful because the receiver coil is being used as a current source as one cannot open circuit it.
[00221] More specifically, this can be used during a start-up procedure while the transmitter side is being initialized, at the beginning of the charge. The circuit could go into standby mode, wait for the transmitter to get ready to put a current into the coil at the rated value, at which time it could enter passive mode and then one of the active modes. For example, the receiver could have a sensor that is adapted to track that the current is at the rated value (or that it is stable enough), but in another variation, the transmitter could indicate that it is ready.
Accordingly, standby mode is a useful safety feature.
[00222] Specifically if, Sa,1 Sb,1 Sc,1 0 [00223] Sa,2 ¨ -S -S ¨ Sc,2 ¨ 0 (33) [00224] Vdc = 0 the wireless receiver coil is effectively shorted. This mode of operation is a useful operating mode for the system when supplied from a wireless charging coil. The integrated charger can wait for the transmitter to establish the required current within the receiver, prior to beginning the charging process. It can also be used once the charging process is finished, while waiting on the transmitter to ramp down and stop the induction of current in the receiver. As the receiver is compensated to behave as a current source, it must never be open-circuited.
[00225] III. Control Approaches [00226] Charging control can be performed on-board the vehicle, as described in the embodiment below.
[00227] As the vehicle drivetrain has been repurposed to serve as the power electronics of the wireless receiver, its associated digital signal processor (DSP) and sensors can be used to perform this control.
[00228] The proposed control approaches in this section using the circuit above are more robust compared to traditional control approaches, as it does not require transmitting sensitive controller feedback signals wirelessly to the transmitter. This also makes the charging process more ubiquitous, as it may eliminate or reduce proprietary communications protocols.
However, the approach is not trivial and requires specific gating signals to be generated as .. well as specific control approaches for the operation of the circuits to regulate and control a flow of power from either (1) only the vehicle side, or (2) the vehicle side in combination with the transmitter side.
[00229] Transmitter power electronics off-board the vehicle are not required to regulate the charging power of the batteries, and can operate at a fixed dc-bus voltage and duty cycle.
They only require sensors for protective purposes (e.g., transmitter coil over-current, etc.). The charging of the batteries is fully controlled by the proposed integrated charger, and uses the control approach / mechanism shown in FIG. 13A.
[00230] FIG. 13A is a block schematic diagram of a control approach of an integrated charger as shown in FIG. 13B.
[00231] The controller uses three control loops, implemented using Proportional Integral (PI) compensators (PI controllers are described as an example but other controllers are possible, such as a PID controller, other more advanced controllers such as non-linear controllers) in order to achieve CC, CV, and energy balancing between the batteries. Gpi_cc is the PI
controller which sets the charging current into the batteries.
[00232] As there are two batteries in the system 1300, the PI controllers control the average current into the batteries, 4_õ9, where:

Ib_avg =
[00233] 2 (34) [00234] The reference charging current, avg'is set by the CV compensator, GpLcv. During CC operation, avgis saturated to the value allowable by the battery management system (BMS), or the maximum charging power allowed from the transmitter (TX), [00235] ib*_õ9,mõ = Min(lb _ay g (BMS),Ib_avg(TX)) (35) [00236] Limiting the charging current is required in order to prevent damage to the batteries and to not exceed the power rating of the wireless power transmission system.
This limit could be a fixed value, for example, stored in onboard memory, or a received value as obtained from a data receiver or other signal as received from the transmitter (e.g., a dynamically set value).

[00237] The system enters CV operation mode when /b*_õ9 < õ9,114õ. Here, the CV
compensator sets the average battery voltage based on the reference voltage, V'bK õg, set by the BMS. The average battery voltage is defined as, [00238] vbl-Fvb2 Vb_avg = 2 (36) [00239] The last controller, Gpi_d, is used to balance the energy of the batteries individually.
This is required as the CC/CV controllers only control the average values of the current and voltage into the batteries. Therefore, Gpi_d is a very slow controller that ensures that, [00240] Vbl = Vb2 = Vb_avg (37) [00241] The controllers can operate simultaneously, in a first embodiment as shown in the top portion of FIG. 13A. In another embodiment, a subset of the controllers can be utilized, but other features may be required to handle the consequences of the missing control. For example, if there is no energy balance controller, it can be difficult to balance the voltage on the batteries if there is a mismatch. If one does not have a current controller or a voltage controller, the control can be performed via the transmitter side, otherwise it may lead to inappropriate charging of the batteries which can result in damage.
[00242] In a system employing two identical batteries, this controller is only required to compensate for small parasitic differences, such as manufacturing tolerances, which may otherwise cause deviations from (37). Gpi_d works by modifying the charging distribution of the batteries by adding a small duty cycle 6(0 to the modulation of the battery with a lower voltage and subtracting the same 6(0 from the modulation of the battery with a higher voltage battery.
In some variations, there can be different batteries. While batteries are described in various embodiments herein, it should be noted that other energy storage media are contemplated, such as super capacitors. Furthermore, mixed energy storage media may be utilized (e.g., a super capacitor and a battery).
[00243] FIG. 14 is a schematic flowchart for the states of the wireless transmitter and the integrated charger. This approach can be used to charge batteries ¨ CC is constant current and CV is constant voltage. The goal is to avoid exceeding the voltage of the battery, as at some point one must lower the current of the charging to ensure that the battery remains below a rated voltage. A constant current mode is used to establish a constant current that gives maximum power to the batteries. This is also limited by the limits previously described earlier.
[00244] In the CC mode, the system could be partially in passive mode and partially in active mode (either A or B, or both). Passive mode would be used to deliver maximum power. Active mode would be toggled on whenever, for example, the system needs to control the charging current to not exceed a limit on the system.
[00245] In the CV mode, the system must be in one of the two active modes.
[00246] Once charging is complete, the system can enter into standby mode. If there is discharging after some time, the system can start charging again, stop, etc.
Other intelligent charging approaches and protocols are contemplated. The charging system does not operate during drive mode.
[00247] The transmitter is only required to (i) detect vehicle, (ii) power up, (iii) detect when the charging is completed and finally (iv) power down. The integrated charger enables its CC/CV controller after it detects that its receiver coil has coupled to a powered transmitter and regulates the charging of the batteries using the control approach in 1300.
The operational requirements imposed on the transmitter can allow for a ubiquitous deployment of wireless charging stations.
[00248] As described herein, during different charge states, the duty cycle can be controlled by a control circuit to control charging characteristics. The duty cycle being utilized can control which mode the circuit can operate in, and in some embodiments, that can include either active mode (when D is greater or less than D = 0.5; in some embodiments just one active mode can be used, in another embodiment, both active modes can be available) or the passive mode (e.g., at D = 0.5). The value of D can depend on the charging point, and for example, can be used to ramp up charging until maximum charge rate is achieved, and then D can be kept at D = 0.5. In some embodiments, the further the deviation from the midpoint D =
0.5, the more power flow to the batteries is reduced. When max power is reached and D is maintained at D
= 0.5, in some embodiments, the traction inverters and drivetrain can be disconnected or disengaged (e.g., to reduce wear and tear or unnecessary use). After max power is no longer desirable, the D levels can then be changed such that it is charges at a lower power (e.g., to slowly charge to "top off" the battery levels, among others. Prior to switching back to an active mode, the traction inverts and drivetrain can be reconnected (or an external voltage source can be connected).
[00249] IV. Simulation Results [00250] The proposed system is simulated in order to show the principle(s) of operation.
The full switched model of the system was simulated in PLECS with the parameters shown in TABLE 2.
[00251] These parameters are extracted from the developed full-scale experimental system.
The mutual inductance of the coils shown are for the well-aligned case (Ax =
0,4 = 0), and for the worst case misalignment (according to SAE J2954) of Ax = 75mm, ,Ay =
ioomm. In this system, the vertical distance between the coils is fixed at z = 200mm.
This height was chosen since a dual inverter drive would most likely be employed in a larger vehicle or van.
[00252] Misalignment causes a change in coupling between the transmitter and the receiver, and the current of the receiver changes. Because of misalignment, the current in the receiver increases, and in order to maintain a same power limit, one might have to reduce the voltage across the receiver coil (e.g., requiring a switching from passive mode to active mode, or if already in active mode, a changing of the duty cycle to accommodate for the misalignment).
[00253] As noted in the simulation cases, one is aligned and one is misaligned. One test, the charging process is started during misalignment, and as shown the system immediately enters active mode and does not enter passive mode.

[00254] TABLE 2 (Simulation and Experimental Parameters) Integrated Charger Parameters Symbol Value Machine phase resistance R., 45 TRQ
Machine leakage inductance Ls 0.5 mH
Battery voltages (nominal) Vi.Vb 2 350V
Rectifier Capacitors CI, C2 20 11.F
Traction inverter switching frequency 10kHz Wireless Parameters Symbol Value Transmitter DC link VT Ai 640V
Transmitter full bridge switching frequency fTx 85 kHz Transmitter Self-inductance 5041/H
Transmitter Compensation Capacitor 6.8nF
Transmitter-Receiver Mutual inductance M 21.5 - 24.6 pH-Receiver Self-inductance Ls 95.5icH
Receiver Compensation Capacitor C, 36.6r/F
Misalignment A.E., Ay 757nm, 100mm Coil-to-Coil Distance z 200m 112 [00255] The wireless coils were sized considering the discussion above.
Specifically, the coils were chosen such that under the perfect alignment, the traction inverter dc-dc can operate in passive mode (while in CC mode), thereby eliminating dc-dc converter losses. The wireless system delivers around 6.6kW under perfect alignment.
[00256] FIG. 15 is an example of a simulation of a complete charging cycle, where irb _õ9 =
360V and the coils are well-aligned. Well-aligned means that the centre-to-centre distance of the wireless coils is zero (i.e. concentric). Mis-alignment is given as a function of the x/y distance between the centres of the two coils, with the maximum case defined in SAE J2954 and used in the simulation and experiments (See Table 2). Vertical Offset is given as coil-to-coil distance which is determined by the vertical distance separating the two coils. A number of traces are shown, showing the Transmitter Voltage (from -500 to 500), the Transmitter Current (from -20 to 20), the Receiver Voltage (from -200 to 200), the Receiver Current (from -50 to 50), the Battery Voltages (from 340 to 360), the Battery Currents (from -10 to 0), the Phase Currents (from 0 to 400), and phase currents (from 0 to 10). The independent variable is Time, from 0 to past 25 seconds.

[00257] The simulation of the system demonstrating a complete charging cycle is shown in simulation 1500. Therefore the experimental setup will be used to show example details of the operation, as well as system dynamics and efficiency for a practical implementation.
[00258] The operation of the wireless system is observed where the wireless system is simply energized at t = 0.05s and turned off at t = 24.5s. The transmitter current is relatively low and therefore incurring low ohmic losses. As noted from (28), the integrated dual inverter charger applies a low back emf voltage onto the receiver (considering it is charging an effective battery voltage of 700V), requiring low flux levels and thus results in low currents in the transmitter.
[00259] The operating modes of the integrated charger is identified in simulation 1500. The charger initially starts in standby mode, where the wireless receiver coil is shorted (i.e. standby mode). At t = 0.5s, the controller described in FIG. 13A is enabled, and immediately transitions the system into CC mode. Also at this point, the dc-dc stage operates in passive mode, since the CC limit (ib_õ9,114õ) has not been reached. This mode of operation incurs no losses in the dc-dc stage, since there is no switching and no current in the traction inverters.
[00260] At t = 11.9s, since the battery voltages have increased, the dc-dc can no longer operate in passive mode and must start switching to regulate the charging power to be less than the CC limit (in this case, this is chosen such that the charging power is 6.6kVV). The effect of the dc-dc converter switching can be seen in the phase currents, where the current becomes non-zero and starts to increase in ripple, according to (32).
[00261] At t = 20.9s, the battery reaches the CV voltage reference, Vb*_õ9 =
360V, and the dc-dc stage transitions to CV mode of operation. In this mode, the dc-dc stage is regulating the voltage on batteries as opposed to the charging current, hence the charging current starts to decrease. The ripple in motor phases also becomes larger as the dc-dc converter duty cycle traverses from near D = 0.5 to D = 0. Interleaving of the dc-dc stage still ensures small ripple on the battery currents.
[00262] At t = 23.5s, the CV controller reaches the desired voltage on the batteries and the charging is completed, therefore the dc-dc stage enters standby mode once again. Once the dc-dc detects the phase current is low (signaling the wireless system has turned off), the dc-dc stage turns off at t = 25s and is ready to enter drive mode.
[00263] FIG. 16 is an example of a simulation of complete charging cycle, where irbK_õ9 =
360V and the coils are misaligned. A number of traces are shown, showing the Transmitter Voltage (from -500 to 500), the Transmitter Current (from -20 to 20), the Receiver Voltage (from -200 to 200), the Receiver Current (from -100 to 100), the Battery Voltages (from 330 to 370), the Battery Currents (from -10 to 0), the Phase Currents (from 0 to 300), and phase currents (from 0 to 15). The independent variable is Time, from 0 to past 25 seconds.
[00264] A second simulation is performed in 1600, where the operation of the system is considered under the worst case misalignment condition, according to SAE J2954 standard.
Under misalignment, it is expected that the current in the receiver will increase, according to (8), since the mutual inductance will decrease.
[00265] Therefore, the dc-dc converter must reduce the back-emf of the receiver, 14, in order to not exceed the 6.6kW charging limit. Aside from increased current in the receiver, the wireless systems behaviour remains unchanged. At t = 0.5s when the integrated charger is enabled, however, the system cannot enter passive mode, and rather must remain in active mode to regulate the charging power to 6.6kW.
[00266] This is clearly visible in the phase currents, which are non-zero and contain some ripple. The rest of the charging is similar, where the integrated charger enters CV mode at t =
20.7s and finally powers off at t = 25s.
[00267] V. Experimental Results [00268] Experimental tests were conducted using a full-scale dual-inverter drive and 110kW
TM4 open-winding EV machine connected to a 6.6kW wireless power transfer system 600.
The dual-inverter has two FS820R08A6P2 (820A/750V) traction inverter modules and two Wolfspeed CAS300M12BM2 (300A/1200V) grid stages. The experimental setup parameters are similar to those in TABLE 2, unless otherwise specified.

[00269] An image of overall experimental setup is shown in FIG. 17. A detailed image of the integrated charger and the EV machine is shown in FIG. 18. Note that the wireless transmitter is operated at a fixed dc-link voltage (Vin = 650V) for all of the following results.
[00270] FIG. 17 is a depiction of the experimental setup showing the system.
In 1700, the system can include all or some of an integrated charger, a compensated receiver coil, a compensated transmitter coil, and/or a transmitter converter.
[00271] FIG. 18 is a depiction of the dual inverter drive integrated charger, along with the EV
machine.
[00272] The first test was conducted to demonstrate the operation of the charger under passive mode. This result is shown in FIG. 19.
[00273] FIG. 19 is a scope output of system performance operating in passive mode. The inherent charge balancing is also shown by setting Vbi= 350V while Vb2=315V.
[00274] The wireless coils are behaving well in FIG. 19, specifically the transmitter current is low with a power factor that enables soft-switching. There is no current within the machine, since the charger is operating in passive mode. In this test, Vb2 was set to be slightly higher than Vbi to demonstrate the inherent charge balancing described in the previous sections.
[00275] The battery with a higher voltage will charge with a lower current.
Finally, the battery currents are well filtered, due to the large dc-link capacitors of the traction inverters.
[00276] FIG. 20 is a depiction of a system performance operating in active mode with D =
0.34.
[00277] Active mode operation is shown in FIG. 20, with D = 0.34. As expected from (23), Vdc is lower than the passive mode, and consequently, the back-emf voltage (177.,) on the receiver is reduced. The effect of the lower back-emf can also be seen on the transmitter current, which is also lower.
[00278] The net result is that the charging power into the batteries is reduced, which is also seen when comparing the battery currents to that of the passive mode. As the dc-dc stage is controlling Vdc, there is current flowing in the machine. Due to the modulation strategy used for the dc-dc stage, it can be seen that the machine phase current is at twice the switching frequency, while there is still negligible ripple entering the batteries. It is also important to note that no shaft movement was observed in the machine, implying that no torque is generated in the machine.
[00279] A plot showing the power into the batteries versus the duty cycle (D) (similar to FIG.
10) was derived experimentally, and shown in FIG. 21. This verifies that it is possible to fully control the power into the batteries by changing the duty cycle of the dc-dc stage.
[00280] FIG. 21 is a plot showing the experimentally measured charging power into the batteries ('N) versus the dc-dc duty cycle (D).
[00281] FIG. 22 is a depiction of a battery current step from 5A to 8A, with the battery currents offset.
[00282] The performance of the battery current controller (Gpi cc) was tested and shown in FIG. 22. This test was done by changing the average battery reference current, 4_õ9, from SA to 8A, demonstrating the dynamic response, as well as the steady state tracking of the controller. It can be seen that the controller increases Vdc in order to increase the charging current into the batteries. The change in the machine phase current can also be observed.
The effect of the change in Vdc can be also visualized in the receiver back-emf as well as the transmitter current.
[00283] As mentioned previously, the battery current controller only controls the average battery current. Therefore the balancing variable, o(t), was introduced to provide individual control over the battery charging currents. The test shown in FIG. 23 was conducted while the CC controller is regulating the average battery current to be 8A. o(t) was changed from 0 to 0.1 instantaneously, which immediately changed the charging distribution of the batteries to be Ibi = 6A, 1b2 = 10A. Even though a step change was done on o(t), it had no effect on the average battery controller (Gpi cc), and that the average battery current is still well regulated to 8A.

[00284] FIG. 23 is a depiction of a set change in 6(0 from 0 to 0.1, showing the ability of the converter to set individual battery currents, at any speed, with no controller interaction with the CC/CV average controllers.
[00285] FIG. 24 is a plot of the overall system efficiency, measuring loss ('N) in three main operating modes (aligned (passive), aligned (active, D = 0.5), and misaligned (active, D =
0.337).
[00286] Finally, the overall system efficiency was measured in order to demonstrate real-world applicability. The overall system efficiency (from the dc input of the transmitter to the batteries) is shown in FIG. 24, along with the loss breakdown in the system.
The highest efficiency is achieved when the receiver-transmitter coils are aligned, and the dc-dc stage is operating in passive mode. The benefit of having low currents in the transmitter can be clearly seen here, as it exhibits very low losses. In this case, the losses in the integrated charger are simply due to the diodes of the grid stage and any parasitic resistance losses. When the dc-dc stage is operated in active mode, the losses are increased in the integrated charger, as the large 820A IGBT modules begin switching at 10Khz.
[00287] However, this mode allows for the control of the charging current in the batteries and is necessary. Finally, the worst case operating mode is when the receiver and transmitter coils are misaligned to the maximum allowable values described in the SAE J2954 standard. In this case, the losses in the dc-dc stage increase, as the conducted current and ripple in the machine will increase. The current in the receiver coil also increases, since the reduced mutual coupling causes an increased current in the receiver coil.
[00288] This loss breakdown is useful as it provides insight into how efficiency can be better optimized in the system, if desired. Overall, these results have shown that good efficiency can still be obtained by using an integrated charging solution, which is not necessarily designed or optimized for wireless charging.
[00289] FIG. 25 is a block schematic of an example commercial implementation of the integrated charger, according to some embodiments. In FIG. 25, a schematic 2500 is shown whereby a transmitter (e.g., a wireless coil) is operated in conjunction with a receiver (e.g., another wireless coil), which is then coupled to a dual inverter drivetrain.
In this example embodiment, the receiver circuitry is retrofit onto an existing dual inverter drivetrain of a vehicle such that the additional switches S1-S4 of FIG. 4 are attached to the existing drivetrain in a stacked series connection as shown in FIG. 4, and additional energy storage devices (capacitors Cl, 02, for example, but not necessarily capacitors as other energy storage devices are possible).
[00290] A controller circuit device is provided to control the operation of the switches S1-S4, and/or a duty cycle D of the dual inverter drive. The controller circuit is a signal generator, such as a pulse-width modulator, that generates gating signals (e.g., 0, 1 signals) that are provided to gates of the switches S1-S4 that effectively control the operation of the switches (e.g., open / closed circuit).
[00291] The controller circuit also couples to the switches of the dual inverter drive to control duty cycle D.
[00292] The controller circuit operates on the receiver side, and can be operated in two modes, a passive mode (see FIG. 7A, 7B), and one of the two active modes A and B (see FIG. 8A, 8B, 9A, 9B). In variant embodiment, the controller can operate in three modes, selectively chosen from the passive mode and both of active modes A and B.
[00293] When unregulated power flow is desired from the transmitter side (or the transmitter side is actively regulating power flow), the passive mode is operated.
[00294] When regulated power flow is required and the receiver side desires to regulate the power flow, one of the two active modes A or B can be utilized. The controller circuit, in different variant embodiments, can be configured to operate only one of active modes A or B
(e.g., it is not necessary to be able to operate in both). The gating signals are generated in accordance with the desired conduction paths for each of the positive and negative half cycles, and the conduction path of the DC-DC stage (for active modes A or B).
[00295] The controller circuit can be provided as a standalone device, and in some embodiments, is a specialized "system on a chip" type circuit storing logic thereon for controlling gate voltages to operate switches accordingly. Additional logic, in a further variation, can be further utilized to establish an interleaving mechanism (e.g., phase-phase interleaving or top-bottom interleaving).
[00296] In another variation, the controller circuit is provided as part of a charging system along with switches S1-S4, and the energy storage devices (e.g., capacitors Cl, 02).
[00297] The controller circuit can be operated for power regulation using feedback loops as shown in FIG. 13A. The feedback loops do not all necessarily need to be implemented, but are provided to show example approaches for power regulation at the receiver side. A set of example modes are shown at FIG. 14 during a charge cycle when a vehicle is detected (e.g., drives onto a charging region), the transmitter coils are energized to transmit energy, and charging is completed. Additional steps may be taken in respect of maintaining a charge (e.g., if the vehicle is left on the charging region for an extended duration of time and there is natural discharge of the batteries). As noted above, charging characteristics may need to be modified in view of mis-alignments or differences in gap size.
[00298] FIG. 26 is a block schematic of another example commercial implementation of the integrated charger, according to some embodiments. In FIG. 26, a schematic 2600 is shown whereby a transmitter (e.g., a wireless coil) is operated in conjunction with a receiver (e.g., another wireless coil), which is then coupled to a dual inverter drivetrain.
In this example embodiment, the receiver circuitry and the controller are provided as an integrated system on-board the electric vehicle.
[00299] This example embodiment is provided as an all-in-one electric vehicle or, in another embodiment, an all-in-one electric vehicle drivetrain, such as an electric vehicle or a drivetrain that is manufactured to have on-board wireless charging capabilities directly from the factory where the on-board wireless charging capabilities include circuitry and gating control logic controllers built-in so that charging flow of FIG. 14 can be implemented using power delivery regulation at the receiver side as controlled using either or both of active modes A and B.
[00300] An optional additional communication link (additional controller circuit for the transmitter side) can be provided to link the transmitter and receiver to allow for communication signals (e.g., sensor signals at the vehicle side indicative of charge levels) that can be received by the transmitter side to regulate power delivery at the transmitter side. If power delivery is being regulated at the transmitter side, the vehicle can be charged entirely in passive mode.
[00301] The term "connected" or "coupled to" may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).
[00302] Although the embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification.
[00303] As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the embodiments are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
[00304] As can be understood, the examples described above and illustrated are intended to be exemplary only.

Claims (41)

WHAT IS CLAIMED IS:

1. An integrated on-board wireless charging device for charging an electric vehicle having a dual-inverter drivetrain during stand-still operation of the electric vehicle, the integrated on-board wireless charging device comprising:
a controller circuit configured to control operation of at least four switches, S1, S2, S3, and S4, S1 and S2 coupled to a first capacitor of a compensated wireless coil and stacked in series to a first traction stage of the dual inverter drive train having a first energy storage and S3 and S4 coupled to a second capacitor of the compensated wireless coil and stacked in series to a second traction stage of the dual inverter drivetrain having a second energy storage;
the controller circuit controlling operation of the at least four switches to selectively control interconnection between a wireless power transmission system delivering an input voltage Vdc and the first traction stage and the second traction stage to establish at least one of two modes of operation:
a first active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D
when 0.5 < D < 1;
a second active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D
when 0 < D < 0.5;
wherein the at least four switches are utilized to establish conduction paths through the first traction stage and the second traction stage.

2. The integrated on-board wireless charging device of claim 1, wherein a passive mode is provided for delivering maximum charging power where the first and second traction stage are not used as a DC/DC stage.

3. The integrated on-board wireless charging device of claim 2, wherein the passive mode is utilized when regulation of power delivery by the integrated on-board wireless charging device is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil, and the at least two modes of operation are utilized when regulation of the power delivery is to be conducted on a receiver side by controlling operation of the compensated wireless coil.

4. The integrated on-board wireless charging device of claim 2, wherein during the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating S1 and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

5. The integrated on-board wireless charging device of claim 1, wherein during the first active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

6. The integrated on-board wireless charging device of claim 1, wherein during the second active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S1 only that charges the first capacitor while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

7. The integrated on-board wireless charging device of claim 1, wherein the controller circuit is adapted for providing charge control on receiver side power electronics.

8. The integrated on-board wireless charging device of claim 7, wherein the controller circuit is adapted for providing the charge control through establishing three control loops adapted to regulate an average current into the first energy storage and the second energy storage.

9. The integrated on-board wireless charging device of claim 1, configured for interoperation with a conductive charging system, the conductive charging system including four relays, R1, R2, R3, and R4, and two capacitors, 01, and 02.

10. The integrated on-board wireless charging device of claim 9, wherein the four relays are adapted to conduct current in a receiver coil and are free of requirements to switch under load.

11. A wireless charging method for charging an electric vehicle having a dual-inverter drivetrain during stand-still operation of the electric vehicle, the wireless charging method comprising:
operating at least four switches, S1, S2, S3, and S4, S1 and S2 coupled to a first capacitor of a compensated wireless coil and stacked in series to a first traction stage of the dual inverter drive train having a first energy storage and S3 and S4 coupled to a second capacitor of the compensated wireless coil and stacked in series to a second traction stage of the dual inverter drivetrain having a second energy storage;
operating the at least four switches to selectively control interconnection between a wireless power transmission system delivering an input voltage Vdc and the first traction stage and the second traction stage to establish at least one of two modes of operation:
a first active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D
when 0.5 < D < 1;
a second active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D
when 0 < D < 0.5;
wherein the at least four switches are utilized to establish conduction paths through the first traction stage and the second traction stage.

12. The wireless charging method of claim 11, wherein a passive mode is provided for delivering maximum charging power where the first and second traction stage are not used as a DC/DC stage.

13. The wireless charging method of claim 12, wherein the passive mode is utilized when regulation of power delivery is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil, and the at least two modes of operation are utilized when regulation of the power delivery is to be conducted on a receiver side by controlling operation of the compensated wireless coil.

14. The wireless charging method of claim 12, wherein during the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating S1 and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

15. The wireless charging method of claim 11, wherein during the first active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

16. The wireless charging method of claim 11, wherein during the second active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S1 only that charges the first capacitor while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC
current.

17. The wireless charging method of claim 11, wherein the controller circuit is adapted for providing charge control on receiver side power electronics.

18. The wireless charging method of claim 17, wherein the controller circuit is adapted for providing the charge control through establishing three control loops adapted to regulate an average current into the first energy storage and the second energy storage.

19. The wireless charging method of claim 11, configured for interoperation with a wireless power transmission system, the wireless power transmission system including four relays, R1, R2, R3, and R4, and two capacitors, C1, and C2.

20. The wireless charging method of claim 19, wherein the four relays are adapted to conduct current in a receiver coil and are free of requirements to switch under load.

21. An integrated on-board wireless charging device for charging an electric vehicle during stand-still operation of the electric vehicle, the integrated on-board wireless charging device comprising:
a controller circuit configured to control operation of at least four switches, S1, S2, S3, and S4, S1 and S2 coupled to a first energy storage coupled to a first capacitor C1 and a compensated wireless coil and S3 and S4 coupled to a second energy storage coupled to a second capacitor C2 and the compensated wireless coil, the controller circuit controlling operation of the at least four switches to selectively control interconnection of a wireless power transmission system delivering an input voltage Vdc to establish a passive mode of operation;
wherein during the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating S1 and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

22. The integrated on-board wireless charging device of claim 21, wherein the integrated on-board wireless charging device is configured to operate in the passive mode when the device is delivering maximum charging power.

23. The integrated on-board wireless charging device of claim 22, wherein the integrated on-board wireless charging device is coupled to a dual inverter drive train or an external power source, and the integrated on-board wireless charging device is configured to operate in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

24. The integrated on-board wireless charging device of claim 21, wherein the integrated on-board wireless charging device is configured to operate in the passive mode when regulation of power delivery by the integrated on-board wireless charging device is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil.

25. The integrated on-board wireless charging device of claim 24, wherein the integrated on-board wireless charging device is configured to operate in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

26. The integrated on-board wireless charging device of any one of claims 23 and 25, wherein during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC
current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC
current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

27. The integrated on-board wireless charging device of any one of claims 23 and 25, wherein during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S1 only that charges the first capacitor while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC

current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

28. The integrated on-board wireless charging device of any one of claims 23 and 25, wherein during the active mode, one of two active modes are utilized: a first active mode where a first traction stage and a second traction stage are used as a DC/DC
converter to regulate Vdc at a duty cycle D when 0.5 < D < 1; and a second active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D when 0 < D <
0.5.

29. The integrated on-board wireless charging device of claim 28, wherein the integrated on-board wireless charging device is configured to operate in either the passive mode, the first active mode or the second active mode depending on a state of the duty cycle D, and the duty cycle D is controllable.

30. The integrated on-board wireless charging device of claim 21, wherein the integrated on-board wireless charging device is configured to operate in a passive mode and the voltage Vdc is regulated by a converter.

31. A wireless charging method for charging an electric vehicle during stand-still operation of the electric vehicle, the wireless charging method comprising:
operating at least four switches, S1, S2, S3, and S4, S1 and S2 coupled to a first energy storage coupled to a first capacitor C1 and a compensated wireless coil and S3 and S4 coupled to a second energy storage coupled to a second capacitor C2 and the compensated wireless coil;
operating the at least four switches to selectively control interconnection of a wireless power transmission system delivering an input voltage Vdc and the first traction stage and the second traction stage to establish a passive mode of operation;
wherein during the passive mode, two conduction paths are generated, a first conduction path during a positive half cycle, and a second conduction path during a negative half cycle, and the first conduction path includes establishing a first set of current loops by operating S1 and S3 to bypass charging of the first energy storage while charging the second energy storage, and the second conduction path includes establishing a second set of current loops by operating S2 and S4 to charge the first energy storage while bypassing charging of the second energy storage.

32. The wireless charging method of claim 31, wherein the passive mode is utilized when delivering maximum charging power where the first and second traction stage are not used as a DC/DC stage.

33. The wireless charging method of claim 32, comprising operating in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

34. The wireless charging method of claim 31, wherein the passive mode is utilized when regulation of power delivery by the integrated on-board wireless charging device is controlled by transmitter-side electronic devices operating in conjunction with a transmitter wireless coil.

35. The wireless charging method of claim 34, comprising operating in an active mode in durations of time when the integrated on-board wireless charging device is not operating in the passive mode.

36. The wireless charging method of any one of claims 33 and 35, wherein during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S3 only that charges the second energy storage while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S2 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

37. The wireless charging method of any one of claims 33 and 35, wherein during the active mode, two conduction paths are generated, a first conduction path during a positive half cycle by operating S1 only that charges the first capacitor while also increasing capacitor voltages with a DC current, and a second conduction path during a negative half cycle by operating S4 only that charges the first energy storage while also increasing capacitor voltages with the DC current; and wherein a conduction path of the DC-DC stage serves to increase the capacitor voltages with the DC current.

38. The wireless charging method of any one of claims 33 and 35, wherein during the active mode, one of two active modes are utilized: a first active mode where a first traction stage and a second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D when 0.5 < D < 1; and a second active mode where the first traction stage and the second traction stage are used as a DC/DC converter to regulate Vdc at a duty cycle D when 0 < D <
0.5.

39. The wireless charging method of claim 38, wherein the integrated on-board wireless charging device is configured to operate in either the passive mode, the first active mode or the second active mode depending on a state of the duty cycle D, and the duty cycle D is controllable.

40. The wireless charging method of claim 21, wherein the voltage Vdc is regulated by a converter.

41. A non-transitory machine readable medium storing machine interpretable instruction sets, which when executed by a processor, cause the processor to perform a method according to any one of claims 11-20, and 31-40.