EP4705139A1

EP4705139A1 - Method and apparatus for integration of onboard chargers into wireless charging systems

Info

Publication number: EP4705139A1
Application number: EP25811900.7A
Authority: EP
Inventors: Ali RAMEZANI; Sepehr SEMSAR
Original assignee: Eleappower Ltd; eLeapPower Ltd
Current assignee: Eleappower Ltd; eLeapPower Ltd
Priority date: 2024-05-27
Filing date: 2025-05-27
Publication date: 2026-03-11
Also published as: EP4705139A4; CN121443479A; WO2025245623A1

Abstract

A new integration method of an onboard charger (OBC) and wireless charger (WC) is proposed. This method integrates the OBC into the wireless charging system (OIW). This method is expected to be suitable for applications where the default charging method is using WC. This method may be suited for high-power applications where multi-phase wireless charging is employed. The principles of the proposed system operation and design considerations are discussed and supported by simulation results.

Description

METHOD AND APPARATUS FOR INTEGRATION OF ONBOARD CHARGERS INTO WIRELESS CHARGING SYSTEMS

CROSS REFERENCE

[0001] This application is a non-provisional of, and claims all benefit including priority to, US Application No. 63/652,109, entitled “METHOD AND APPARATUS FOR INTEGRATION OF ONBOARD CHARGERS INTO WIRELESS CHARGING SYSTEMS”, filed May 27, 2024, incorporated herein by reference in its entirety.

FIELD

[0002] Embodiments of the present disclosure relate to electrical systems, circuits and devices, and more specifically, embodiments relate to devices, systems and methods for improved integration of wireless and onboard charging systems, namely for integration of onboard chargers into wireless charging systems, for example, for practical use with electric vehicles.

INTRODUCTION

[0003] Wireless power transfer (WPT) using wireless charging (WC), DC charging, and onboard charging (OBC) are the primary methods for charging electric vehicles (EVs) at different power levels. Onboard charging involves physically connecting the vehicle to a charging station using a cable, while wireless charging uses electromagnetic induction to transfer energy from a charging pad on the ground assembly (GA) to a receiver on the vehicle.

[0004] The OBC is a converter that is typically installed in an EV that has two power conversion stages. The first stage is called the power factor correction (PFC), which converts the input alternate current (AC) into direct current (DC) while meeting the total harmonic distortion (THD) requirements for interconnection with the electric grid. The second stage is the DC-to-DC conversion stage, which usually involves a transformer to provide galvanic isolation. In the second stage, the DC voltage produced by the PFC stage is converted back to a high-frequency AC, passed through an isolation transformer, and then rectified into DC again to charge the electric vehicle battery. [0005] A wireless charging system contains a receiver and transmitter coil which generates an induced current within the receiver coil through a magnetic field generated by the transmitter coil. The magnetic coupler of a wireless charger can be designed in different shapes, such as rectangular, circular, Double-D (DD), DDQ, etc. Moreover, the magnetic coupler and power converter can be either a single or multi-phase system.

[0006] Typically, multi-phase wireless charging systems are employed in different applications to increase the power level and avoid high-rating components. As the number of phases increases, the complexity increases, therefore, a trade-off between the cost and the number of phases should be considered when designing a power converter. Moreover, crosscoupling each phase coil can cause design challenges. Three-phase wireless chargers for roadway power have been proposed. However, due to using long transmission coils, EMI issues are inevitable. Trifoliate wireless charging magnetic couplers have been proposed. However, the Trifoliate wireless charging magnetic coupler is affected by cross-coupling between the phases. Moreover, each phase only occupies one-third of the magnetic coupler surface area. As the circuitry and complexity of the proposed WC solutions increase, weight, cost and assembly time increases, leading to WC systems being an expensive add-on to preexisting conventional OBC systems. Therefore, improved systems and methods for OBC and WC are desired.

SUMMARY

[0007] Methods and systems are proposed for integrating the OBC and WC systems in EVs. In the proposed method and system, some of the components such as resonant inductors, resonant capacitors, and a rectifier are shared between the OBC and WC systems. Therefore, this solution helps to reduce the overall cost of a vehicle assembly (VA) when both wired and wireless charging methods are required. The principles of this integration method, different topologies and simulation results are presented.

[0008] An integrated charging system is proposed for electric vehicles, the system is capable of transferring power wirelessly and through direct charging. The integrated charging system contains a first power source within a wireless ground assembly, the first power source is electrically coupled to a wireless transmitter and the wireless transmitter contains at least one coil for producing a magnetic field. A second power source is electrically coupled to a transformer located within an enclosure. A current splitting device comprised of at least the transformer, a wireless receiver and a shared resonant network, where the wireless receiver has at least one coil which receives an induced current from the magnetic field of the wireless transmitter when aligned with the at least one wireless transmitter coil. The resonant network is electrically coupled to each of the at least one coil of the wireless receiver. A shared rectifier is electrically coupled to the resonant network and an energy storage device, the energy storage device is configured to store power received from at least one of the wireless transmitter and transformer. The current splitting circuit has a first connection point and a second connection point, where the first connection point is located at a node on one of the wireless receiver and resonant network, the second connection point connected in parallel with the shared rectifier, and the transformer is electrically coupled to the first connection point and second connection point for transferring current through the current splitting circuit. The first connection point taps into one of the wireless receiver and resonant network at a neutral point which splits into two or more symmetrical electrical paths for the current to flow to the energy storage device.

[0009] A method is proposed for integrated charging of an electric vehicle capable of being charged through wireless and direct charging. The method comprises generating a magnetic field through at least one coil of a transmitter within a wireless ground assembly when the wireless transmitter is receiving power from a first power source. Generating an output of current from a transformer located within an enclosure when the transformer is receiving power from a second power source. Providing a current splitting device containing at least the transformer, a wireless receiver and a shared resonant network, and the wireless receiver having at least one coil which receives an induced current from the magnetic field of the wireless transmitter when aligned with the at least one wireless transmitter coil, and the resonant network electrically coupled to each of the at least one coil of the wireless receiver. Coupling a shared rectifier to the resonant network and an energy storage device, the energy storage device storing power transmitted from at least one of the wireless transmitter and transformer. Further, the current splitting device has a first connection point and a second connection point, the first connection point located at a node on one of the wireless receiver and resonant network, the second connection point connected in parallel with the shared rectifier, and the transformer having an electrical coupling to the first connection point and second connection point for transferring current through the current splitting circuit. Lastly, the first connection point taps into one of the wireless receiver and resonant network at a neutral point which splits into two or more symmetrical electrical paths for the current to flow to the energy storage device.

[0010] In some embodiments, the first connection point is located on the resonant network.

[0011] In some embodiments, the resonant network has at least two time varying circuit components, and the first connection point is placed at a symmetrical point of the resonant network between the at least two time varying circuit components.

[0012] In some embodiments, the first connection point is located on the wireless receiver.

[0013] In some embodiments, the wireless receiver comprises two or more coils, and the first connection point is placed at a symmetrical point between the two or more coils.

[0014] In some embodiments, the wireless receiver is one of a uni-polar, multi-polar, circular, rectangular and double-D coil structure.

[0015] In some embodiments, the resonant network is any one of a series, LLC, Y-series and A-series compensation.

[0016] In some embodiments, the current splitting circuit is located proximal to the transformer.

[0017] In some embodiments, the current splitting circuit is located inside the enclosure.

[0018] In some embodiments, the shared rectifier is a full bridge rectifier.

[0019] In some embodiments, the energy storage device is a battery, and the battery, wireless receiver, resonant network, shared rectifier and transformer are housed in a shared charging assembly within an electric vehicle assembly. [0020] In some embodiments, the shared charging assembly contains shared physical components comprising at least one of an enclosure, printed circuit boards, connectors, contacts, heatsinks, thermal pads, cold plate, and cables.

[0021] In some embodiments, each of the at least one coil of the wireless receiver is coupled to the resonant network through an active switching component.

[0022] In some embodiments, a controller is coupled to the active switching component, the controller modulating the active switches to disconnect the wireless receiver when the transformer is receiving current from the second power source.

[0023] In some embodiments, the transformer is directly coupled to the first connection point.

[0024] In some embodiments, a fuse is coupled between the first connection point and the transformer to permit bi-directional charging.

[0025] The integrated charging system of claim 1 , wherein a compensation capacitor is coupled between the first connection point and the transformer to permit bi-directional charging.

[0026] In some embodiments, the second power source is a portable generator or high- capacity battery.

[0027] Structural components include, but are not limited to an onboard charging network comprising a power factor correction circuit and an inverter. A wireless charging network comprising a power factor correction circuit, an inverter and a wireless charger transmitter and receiver. An integrated charging component comprising a current splitting circuit and a rectifier. The integrated charging component providing as an output a charging power to a battery.

[0028] In use, the integrated charging component interoperates with the onboard charging network and the wireless charging network to perform steps of a method including, but not limited to receiving power from either the onboard charging network or wireless charging network, using the current splitting circuit to receive the power and convert the power to a desired resonant frequency and/or power rating, converting the power from AC to DC which is then provided to the battery for charging.

[0029] The system may be used for high voltage vehicles such as buses, trucks, industrial equipment (i.e. cranes, forklifts, etc.), taxis, consumer vehicles, drones and the like. The system and method may be integrated into a drivetrain of an electric vehicle. As wireless charging may be preferred when charging at a high voltage, the proposed system and method may be configured to have the WC as the default charging mode, and the OBC may be a back-up option available to the user when needed.

[0030] The system is configured to interoperate with standard ground charging systems for wireless charging. The system may be implemented as a retrofit within an existing vehicle assembly, or may be sold as a stand-along circuitry structure which can be implemented within a new build vehicle. For example, the proposed system may be used for wireless charging of vehicles which have a wireless receiver pad positioned preferably on the exterior of the bottom/floor of the vehicle structure. The receiver pad may be aligned with a transmitter pad (i.e., through manoeuvring and parking the vehicle over the pad) which may permit the receiver pad to receive an induced current from the magnetic field generated by the transmitter pad. Further, the proposed system may be used for on-board charging which may comprise direct electrical coupling between a charging station and an input terminal on the vehicle. The charging station may transfer current to the input terminal which is electrically coupled to a transformer within the vehicle assembly. The transformer may step down or step up the voltage received from the charging station to a voltage level suitable for the electric vehicle energy storage device within the vehicle assembly.

[0031] In some embodiments, the proposed system may be suitable for autonomous vehicles and electric vehicles with high power ratings. When used for an autonomous vehicle, such as a taxi, passenger vehicles, vacuum cleaner, arial drone, etc., the wireless charging mode may be the preferred charging approach, allowing the autonomous vehicle to return without user intervention to a charging station after the battery has been depleted below a predetermined threshold. However, due to the integration of the OBC within the system, an autonomous vehicle would have the ability to receive a charge from a mechanically connected charging source (i.e. through a terminal) if it was incapable of returning to the charging station. [0032] When used for an electric vehicle with a higher power rating then most consumer vehicles, such as a bus, transport vehicles, cranes, forklifts, or other vehicles used in shipping and warehouse operations, the proposed system and method may permit the transfer of a high voltage source in WC mode which thereby reduces downtime and allows the vehicles to return to operation with a full charge in a relatively short amount of time.

[0033] In some circumstances, OBC mode may be preferred for charging, even if it would be possible to return to a charging station. For example, when the vehicle battery has reached below a minimum threshold, such as 30% charge, it may be preferable to use the OBC mode in order to preserve battery health due to the potential damage which can be caused by exposing the depleted battery to the higher power provided in WC mode.

[0034] Further, if an electric vehicle is unable to return to a ground charging station prior to the battery being completely or substantially depleted, the electric vehicle may be able to have a power source brought to its location (such as a portable generator) which can charge the electric vehicle in OBC mode such that the battery is returned to a power level sufficient to arrive at a ground charging station to receive the remaining charge through a WC.

[0035] The proposed system may be designed for the WC mode to be the primary charging method. The high voltage which is capable of being provided by the proposed system in WC mode allows for more efficient and timely charging without the need to have a person present at the time of charging to connect physical terminals. However, the integrated circuit provides the possibility of OBC mode at a reduced cost and complexity, due to the shared components, which can be used as a fail safe if an electric vehicle would prefer OBC mode or otherwise be unable to reach a ground charging station.

[0036] The improvements proposed herein can help improve the adoption of certain technologies such as, but not limited to, electric and hybrid vehicles, and adoption of these green technologies can help mitigate environmental impacts and conserve the natural environment and natural resources. DESCRIPTION OF THE FIGURES

[0037] 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.

[0038] Embodiments will now be described, by way of example only, with reference to the attached figures, wherein in the figures:

[0039] FIGs. 1A, 1 B and 1C are diagrams of bipolar three phase magnetic couplers disclosed in the prior art.

[0040] FIG. 2 is a circuit diagram of a bipolar three phase magnetic coupler disclosed in the prior art.

[0041 ] FIG. 3A is a component diagram of a configuration of conventional vehicle assembly with separate on board charging and wireless charging systems, according to some embodiments.

[0042] FIG. 3B is a component diagram of a configuration of an integrated onboard charging and wireless charging system, according to some embodiments.

[0043] FIG. 4A is a circuit diagram of an integrated wireless charger topology with a singlephase WC with a series compensation (Type A), according to some embodiments.

[0044] FIG. 4B is a circuit diagram of an integrated wireless charger topology with a singlephase WC with a series compensation and an OBC with a series compensation on the primary side (Type B), according to some embodiments.

[0045] FIG. 4C is a circuit diagram of an integrated wireless charger topology with a singlephase WC with an LCC compensation (Type C), according to some embodiments.

[0046] FIG. 4D is a circuit diagram of an integrated wireless charger topology with a three- phase WC with a series compensation and half-bridge OBC (Type D), according to some embodiments. [0047] FIG. 4E is a circuit diagram of an integrated wireless charger topology with a three- phase WC with a Y-series compensation and full-bridge OBC (Type E), according to some embodiments.

[0048] FIG. 4F is a circuit diagram of an integrated wireless charger topology with a three- phase WC with a A-series compensation and half-bridge OBC (Type F), according to some embodiments.

[0049] FIG. 4G is a circuit diagram of an integrated wireless charger topology with a singlephase WC with an LCC compensation and half-bridge OBC (Type G), according to some embodiments.

[0050] FIG. 4H is a circuit diagram of an integrated wireless charger topology with a three- phase WC with a Y-Parallel compensation and half-bridge OBC (Type H), according to some embodiments.

[0051] FIG. 4I is a circuit diagram of an integrated wireless charger topology with a singlephase WC and a single-phase OBC, according to some embodiments.

[0052] FIG. 5A is a circuit diagram of Type A topology in wireless charging mode, according to some embodiments.

[0053] FIG. 5B is a simplified equivalent circuit diagram of Type A topology in wireless charging mode, according to some embodiments.

[0054] FIG. 5C is a circuit diagram of Type A topology in onboard charging mode, according to some embodiments.

[0055] FIG. 5D is a simplified equivalent circuit diagram of Type A topology in onboard charging mode, according to some embodiments.

[0056] FIG. 6A is a circuit diagram of Type D topology in wireless charging mode, according to some embodiments. [0057] FIG. 6B is a simplified equivalent circuit diagram of Type D topology in wireless charging mode, according to some embodiments.

[0058] FIG. 6C is a circuit diagram of Type D topology in onboard charging mode, according to some embodiments.

[0059] FIG. 6D is a simplified equivalent circuit diagram of a Type D topology in onboard charging mode, according to some embodiments.

[0060] FIG. 7A is a circuit diagram of Type G topology in wireless charging mode, according to some embodiments.

[0061] FIG. 7B is a simplified equivalent circuit diagram of Type G topology in wireless charging mode, according to some embodiments.

[0062] FIG. 7C is a circuit diagram of Type G topology in onboard charging mode, according to some embodiments.

[0063] FIG. 7D is a simplified equivalent circuit diagram of Type G topology in onboard charging mode, according to some embodiments.

[0064] FIG. 8A is a series of graphs of voltage and current showing simulation results of a

6.6 kW integrated single-phase Type A topology in wireless charging mode, according to some embodiments.

[0065] FIG. 8B is a series of graphs of voltage and current showing simulation results of a

6.6 kW integrated single-phase Type A topology in onboard charging mode, according to some embodiments.

[0066] FIG. 9A is a series of graphs of voltage and current showing simulation results of a

6.6 kW integrated three-phase Type D topology in wireless charging mode, according to some embodiments. [0067] FIG. 9B is a series of graphs of voltage and current showing simulation results of a 6.6 kW integrated three-phase Type D topology in onboard charging mode, according to some embodiments.

DETAILED DESCRIPTION

[0068] Different types of circuits and resonant networks are proposed for OBC and WC. In conductive charging systems (i.e., OBC), one or more of a dual active bridge (DAB) without a compensation network, LLC, CLLC and their multi-phase variants may be used. In wireless chargers, different types of resonant compensation such as S-S, LCC-S, LCC-LCC, S-LCC, and other complex topologies are proposed to improve the efficiency and performance under misalignment of the magnetic couplers.

[0069] Typically, multi-phase wireless charger systems are employed in different applications to increase the power level and avoid high-rating components. As the number of phases increases, the complexity increases, therefore, a trade-off between the cost and the number of phases should be considered when designing a power converter. Moreover, crosscoupling each phase coil can cause design challenges. Three-phase wireless chargers for roadway power have been proposed. However, due to using long transmission coils, EMI issues are inevitable. Trifoliate wireless charging magnetic coupler have been proposed. However, the Trifoliate wireless charging magnetic coupler is affected by cross-coupling between the phases. Moreover, each phase only occupies one-third of the magnetic coupler surface area. In FIGs. 1A, 1B and 1C, variations of 50 kW bipolar three-phase magnetic couplers are shown. As seen in the configurations of couplers 100, each phase is divided into two sections, and each section mirrors the other, placed on the opposite side. In this configuration, phases will overlap with an opposing and corresponding phase. However, overall cross-coupling may be minimized using the multi-layer configurations shown in FIG. 1B and FIG. 1C.

[0070] As shown in FIG. 2, a circuit diagram of a wireless charging system 200 including a bipolar three phase magnetic coupler disclosed in the prior art may have a ground assembly (GA) side and a vehicle assembly (VA) side. On the GA side, a power source 202 is electrically coupled to a power factor correction circuit and inverter which act to provide conditioned power to the GA side transmitter 204. The transmitter 204 contains a three-phase magnetic coupler which generates a magnetic field M_gv, M_vg when the conditioned power flows through the coil branches of the transmitter 204. When the magnetic field of the transmitter 204 is aligned with the VA side receiver 206, an induced current is generated within the coil branches of the VA side receiver 206 which is conductively transmitted to a vehicle assembly circuit comprising a resonant network, a rectifier and an energy storage device 208.

[0071] A schematic of a conventional EV charging system 300A is shown in FIG. 3A. The conventional assembly 300A contains a WC system 304 which may be substantially similar to the circuit diagram shown in FIG. 2, and a separate OBC system 302. The OBC system 302 is configured to electrically couple to an AC grid system 306 (i.e. a generator, public grid, portable generator, etc.) for a power supply through wiring containing a terminal at both ends.

[0072] In the OBC system 302 enclosure, the PFC 308 receives AC from the AC grid system 306 and reduces the phase shift between the supplied voltage and current, thereby reducing the reactive power (i.e. wasted energy) and bringing the power factor closer to 1. The PFC 308 may be a delta connected capacitor bank, a star connected capacitor bank, or contain active elements (i.e. diodes and switches).

[0073] The inverter 310 receives the corrected power and converts the DC into AC using a series of switches. The inverter 310 may be a single phase or three phase inverter, depending on the load and/or magnetic coupling system used in the system 300A. The transformer 312 receives AC from the inverter 310 and the primary winding of the transformer 312 generates a magnetic field which transfers flux from the primary winding to the secondary winding thereby generating an induced voltage within the secondary winding.

[0074] The transformer 312 may be a step-down transformer which reduces the voltage received from the AC grid to an amount that can be used to safely charge the EV battery 318.

[0075] The resonant network 314 reduces the impedance within the power supply such that the current supplied to the battery 318 is maximized. The resonant network 314 tunes the frequency of the incoming power to the resonance frequency of the circuit. The resonant network 314 may use a combination of resistors, capacitors and inductors to store the energy, provided by the transformer 312, in a state of oscillation depending on the desired resonant frequency. The resonant network 314 may be an S-S, LCC-S, LCC-LCC or S-LCC circuit in either series or parallel.

[0076] The rectifier 316 converts the AC into DC through the use of diodes, such as through a full bridge rectifier. The rectifier 316 provides the converted DC power supply as an output of the OBC system 302. The OBC system 302 is coupled to the EV battery 318, which allows the EV battery 318 to receive a charge from the DC power supplied by the rectifier 316.

[0077] The WC system 304 in the conventional assembly 300A is magnetically coupled to a wireless ground assembly 320. The WC system 304 has similar stages to the OBC system 302, except for the isolation transformer 312. The isolation transformer 312 of the OBC system 302 is replaced by a loosely coupled transformer (324, 326) with an air gap. This loosely coupled transformer's primary and secondary side windings are typically referred to as the transmitter 324 and receiver 326 coil in the wireless charging system 304.

[0078] The wireless ground assembly 320 acts to transfer power from the AC grid 306 to the WC system 304. The wireless ground assembly 316 contains a PFC 308 and inverter 310 which perform similar functions as discussed above when describing the OBC system 302.

[0079] The inverter 310 is coupled to a wireless charger transmitter 324. The wireless charger transmitter 324 can be magnetically coupled to a receiver 326 (i.e. , when the two components are aligned) and forms a loosely coupled transformer with an air gap that is configured to transfer power across the transmitter 324 and receiver 326 coils through a magnetic field which transfers flux across the air gap. Therefore, the magnetic field generated by the transmitter 324 induces a current within the receiver 326 coils when the receiver 326 and transmitter 324 are aligned. The wireless charger receiver 326 is coupled to a resonant network 314 which stores the energy at the desired resonant frequency, the resonant network 314 is coupled to a rectifier 216 which converts the AC power supply to DC.

[0080] The rectifier 316 is configured to generate a DC power supply which can be used as an output of the WC system 304, the WC system 304 is configured to provide the DC power supply to the EV battery 318 for charging through a conductive pathway. Due to the conventional assembly 300A lacking integration between the WC 304 and OBC 302 systems, there is a duplication of electrical and mechanical components adding to the weight, complexity and inefficiencies within the charging environment. Therefore, when designing vehicle assemblies, a decision may have to be made to implement either a WC system 304 or a OBC system 302, but not both, in order to conserve space and reduce the overall cost of the vehicle. Further, if it is desirable to have both the WC system 304 and OBC system 302 within a single vehicle assembly, the WC system 304 may be an “add-on” feature which, due to requiring a completely separate set of circuit and structural components, is only available to those able to afford the increased cost.

[0081] Since the On-Board Charger (OBC) system 302 and the Wireless Charger (WC) system 304 both contain some electrical and structural components which could be shared, it may be possible to integrate the OBC 302 and WC 304 systems into a shared topography. Additionally, both the OBC 302 and WC 304 systems function at a relatively high switching frequency of 50 to 150 kHz, which means that the frequency response of the filters and resonant tanks may be similar in both systems. Therefore, combining the OBC 302 and WC 304 systems offers several benefits over traditional systems.

[0082] However, integrating the OBC 302 and WC 304 systems into a shared topography may lead to the integrated system favouring the OBC mode since it may be simpler to use the existing circuitry of the OBC system 302 as a coupling point for the wireless charger receiver 324. If the OBC system 302 is used as the base for the shared circuitry, then as would be evident, the design and efficiency of the integrated system may result in the OBC mode being more efficient than the WC mode. The choice to prioritize the OBC system may be due to issues of magnetic field leakage from the receiver 326 coils which may occur if the transformer 312 of the OBC system 302 is coupled to the wireless charger system 304. For example, under an integrated system where the WC 304 system is used as the coupling point, if current flows from the OBC system 302 through the receiver 326 while the receiver is not aligned with a corresponding transmitter 324, a dangerous amount of magnetic field leakage may be generated by the receiver 326. Magnetic field leakage from the receiver 326 coils of the WC system 304 may pose dangers to both individuals and objects in the vicinity of the receiver 326 coils. [0083] However, as wireless charging becomes more efficient and desirable for electric vehicles, it may be preferrable to have a system where the default, and favoured charging mode, is wireless, while still maintaining the ability to utilize OBC mode when needed. This may be the case for autonomous vehicles which would be able to receive a charge without the need for a user being present to mechanically couple the terminals of the OBC system 302. Further, wireless charging may be more efficient for high power vehicles which can be charged faster using the higher power transfer capabilities of wireless charging. However, an integrated charging system which seeks to favour WC mode over OBC mode may have to address the issues of magnetic field leakage in order to provide a safe operating environment.

[0084] The proposed integration system and method is shown in FIG. 3B, where the OBC system 302 is coupled to a current splitting circuit 330 which may use a magnetic and/or capacitive component of the WC system 304 as a coupling point (or intermediate tap).

[0085] The integrated system 300B contains an integrated WC and OBC network 328 which contains a shared current splitting circuit 330 and a shared rectifier 334. The current splitting circuit 330 may be a magnetic component (inductive network), a capacitor bank (capacitive network), or a combination of both. For example, the current splitting circuit 330 may be a resonant network such as a S-S, LCC-S, LCC-LCC or S-LCC circuit in series or in parallel. In another example, the current splitting circuit 330 may be the wireless charger receiver coil. The transformer 312 (not shown) of the OBC is treated as being within the current splitting circuit 330 and is electrically coupled to the output of the inverter 310. The shared rectifier 334 converts the AC power supply to DC. The shared rectifier 334 provides a DC power supply as an output of the integrated WC and OBC network 328, the WC and OBC network 328 provides the DC power supply to the EV battery 318 for charging.

[0086] Unlike in previous system 300A which had a separated WC and OBC system, the proposed integrated system 300B may use the WC system (i.e., receiver 326) as the primary side of the circuit, and the OBC system (i.e., transformer 312) acts as a secondary side which connects to some part of the primary WC system. Therefore, it should be appreciated that the WC may act as the default charging mode, while the OBC mode is available as a backup/alternative mode of charging. By separating the functions of the OBC and WC modes into a primary and secondary mode of charging, the integrated system 300B can integrate the two systems through a coupling point on the WC side of the system and share certain electrical and structural components such as resonant inductors, resonant capacitors, heatsinks, sensors, microcontrollers, etc. Further, by sharing components, the overall size and weight of the charging system 300B can be reduced, resulting in a more efficient and cost-effective solution. In addition, the integrated system 300B allows for seamless switching between wired and wireless charging methods, providing greater convenience for users.

[0087] The proposed topologies of the integrated system 300B include a single or a multiphase wireless charger as shown in FIGs. 4A, 4B, 4C, 4D, 4E, 4F, 4G and 4H. It should be noted that in these figures, the transmitter 324 of the wireless charging system 304 is not shown to save space. In practice, any type of transmitter 324, including single-phase, multiphase and multi-transmitter or multi-receiver systems can be considered for the wireless charging system.

[0088] The current splitting circuit 330 can be a magnetic component (inductive network), a capacitor bank (capacitive network), or a combination of both. The magnetic component can be the transformer 312 of the OBC but more preferably is the intermediate tap 404 of the wireless charging receiver coil as shown in FIG. 4A. Alternatively, capacitive current splitting circuits can be considered as shown in FIG. 4G. The current splitting circuit 330 can be understood as having a connection point which acts as the electrical connection between the WC and OBC systems. In some embodiments, the connection point is the intermediate tap 404 on a magnetic structure. In some embodiments, the connection point is the resonant tap 410 on a resonant network.

[0089] In some embodiments, the current splitting circuit 330 is a magnetic component which acts as a connection point between the OBC and WC systems (i.e. , the transformer 312 and receiver 324). For example, the transformer 312 of the OBC can be electrically coupled to the receiver 326 coil of the WC system at an intermediate tap 404. Preferably, the intermediate tap 404 is a center point on the receiver coil 326, which creates a symmetrical current flow in opposing directions of the receiver 326. As a result of using the receiver 326 as the current splitting circuit 330, the nominal charging current from the OBC transformer 312 will flow through the wireless charger receiver 326 coil. Therefore, a magnetic field may be generated by the WC receiver 326, which may be harmful to living objects and cause heating in the surrounding metallic objects. Moreover, generating an uncontrolled magnetic field on the WC receiver coil 326 while the system is operating in OBC mode may violate safety standards. If the magnetic structure (in this case, the wireless charger receiver coil 326) of the VA side is designed symmetrically and the OBC transformer 312 is connected to the center point of that winding (i.e., an intermediate tap 404), the magnetic field emissions can be mitigated. In some cases, asymmetry may be added intentionally or unintentionally to achieve a different magnetic field emission.

[0090] In some embodiments, a shared resonant network can be used as a current splitting circuit 330 between the OBC and WC systems. If the OBC transformer 312 connects to any arbitrary point on the shared resonant network, it may cause current circulation into the WC receiver coil 326, which may not be desirable due to magnetic field leakage resulting from the circulating current in the WC receiver coil 326 in OBC mode generating magnetic field emissions and heating up metal objects around the receiver coil 326. Alternatively, a current splitting circuit 330, in this case using a mid-point on the shared resonant network, may be used as the connection point for the OBC transformer 312. For example, a resonant capacitor may be divided into two or more effective elements (i.e., two or more time varying circuit components such as capacitors), and the OBC may be connected to the midpoint of the time varying circuit components. The operating principle of this embodiment would lead to a circuit for transmission of the OBC current that passes no current through the WC receiver 326 coil. This may result in a symmetrical topography in relation to the OBC transformer 312 connection point, which can avoid the generation of magnetic field emissions. The current splitting circuit 330 may be placed on the VA coil side, close to the OBC, in the OBC enclosure, or within a separate temperature and noise controlled enclosure depending on the application requirements. In some embodiments, when the current splitting circuit 330 comprises the shared resonant network, the shared resonant network may be the WC resonant network 314 located proximal to the WC receiver coil 326. In another embodiment, when the current splitting circuit 330 comprises the shared resonant network, the shared resonant network may be the OBC resonant network 314 located proximal or within the OBC system 302 enclosure.

[0091] In some embodiments, the current splitting circuit 330 uses the OBC resonant network 314 located within the OBC system enclosure 302. Placing the current splitting circuit 330 inside the OBC system enclosure 302 may reduce EMI noise to the wireless receiver 326 coils. A further technical benefit of using the OBC resonant network 314 for the current splitting circuit 330 is that the current flowing to the WC receiver 326 while operating in OBC mode is zero, or substantially zero. Therefore, the risk of magnetic field leakage is substantially reduced. A further technical benefit of using the OBC resonant network 314 located within the OBC system enclosure 302 for the current splitting circuit 330 is that the passive components of the resonant network 314 may require a less complex configuration to achieve a substantially symmetrical topography for the connection point of the integrated system. Achieving symmetry within a magnetic structure such as the receiver 326 coils may require having identical coil dimensions which have a lower tolerance for misalignment, may require more complex circuitry and may lose symmetry over time due to movement of the coils.

[0092] A potential benefit of having a capacitive current splitting network (i.e., using the resonant network as the connection point), is that it may not require changes to the magnetic coupler (i.e., receiver 326) of the wireless charging system and avoid magnetic field generation on the receiver 326 coils while the OBC mode is operating.

[0093] The current splitting circuit 330 may be connected to a full bridge rectifier 334 in the integrated system 300B. A full bridge rectifier 334 may cause the diodes within the full bridge rectifier to be exposed to half the current that would otherwise be provided to the internal components of a voltage doubler. This may be desirable for managing high power ratings and transferring higher power from the wireless charger transmitter 324. In some cases, it may be beneficial to use another type of rectifier solution, such as a voltage doubler, for example when the resonant network 314 has a lower current rating.

[0094] Therefore, the proposed method and system for an integrated charging circuit 300B can be adapted for applications in which the WC may be the primary charging method, and the OBC may be a backup charging mechanism. Therefore, it can be assumed that the proposed integrated solution is more suitable for high power WC applications. In other words, the OBC system may be integrated into the WC system as a backup option rather then being an add on as a separate system. This does not limit the performance of the OBC mode or the capability to run continuously using either WC or OBC mode. [0095] While specific embodiments have been described, the description is meant to be illustrative and is not to be construed as limiting the embodiments. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the embodiments. For example, the passive rectifier 334 can be replaced by an active bridge made by switches instead of diodes which may permit active control of the system 300B through pulse width modulation of the active switches and a reduction in the forward voltage drop across the diodes.

[0096] FIG. 4A shows a circuit diagram 400A of an integrated wireless charger topology with a single-phase WC receiver 326 with a Series compensation (Type A), according to some embodiments. In this system, the OBC system 302 is a single-phase converter with a singlephase isolation transformer 402. The secondary winding of the OBC transformer 402 terminal is connected to the intermediate tap 404 of the wireless charger receiver coil 326 . The other terminal of the OBC transformer 402 can be connected at the second intermediate tap 406 of the DC-link capacitor or another half-bridge made by two diodes. Moreover, the series resonant capacitor bank (C_r) on the VA side of the wireless charger receiver 326 is divided into two sections with an equivalent capacitance of 2xC_r.

[0097] In WC mode, the receiver 326 coil is connected to a series compensation, C_r (the equivalent of two capacitors in the series branch). In this case, the symmetrical winding section currents of the receiver coil 326 are in the same direction (i.e., I_ri=-lr2) which results in a magnetic field that magnetically couples with the transmitter 324 of the wireless charging system. Both terminals of the receiver 326, which extend from each of the receiver 326 coils, are connected to a full-bridge rectifier 410. The circuit 500A operating in WC mode and its simplified equivalent model 500B based on fundamental harmonic analysis (FHA) are presented in FIG. 5A and FIG. 5B, respectively. In FIG. 5B, V_oc is the open circuit voltage induced by the transmitter 324 of the wireless charger to the receiver 326 side of the wireless charging system. This induced voltage is equal to /Wfr^xwjx/_f; where M_tr is the mutual inductance between the transmitter 324 and receiver 326 coils of the wireless charging system, It is the transmitter coil current, w is the angular frequency of the transmitter current, and j is the imaginary unit. [0098] In OBC mode operation, the secondary winding current, l_s, will be divided in half and flows in opposite directions (i.e. I_ri=lr2=lsl2) as shown in circuit 500C seen in FIG. 5C. Thus, a symmetrically built receiver 326 coil (L_r) would have a zero sum of magnetic flux at a certain distance from the coil due to cancelation. The simplified equivalent circuit 500D operating in OBC mode is shown in FIG. 5D. The voltage on the secondary side of the OBC transformer 402 is represented by \/_s in FIG. 5D.

[0099] Compared to a conventional system 300A, the number of the required diodes is reduced to four instead of eight. Moreover, the resonant capacitor is shared between the WC and OBC systems to improve efficiency and reduce costs.

[00100] FIG. 4B shows a circuit diagram 400B of an integrated wireless charger topology with a single-phase WC receiver 326 and a series compensation, and the OBC transformer 402 configured with a series compensation on the primary side (Type B), according to some embodiments. The transformer 402 of the OBC system is connected to the intermediate tap 404 of the receiver 326 coil and the second intermediate tap 406 of the DC-link capacitors. An extra series capacitor can be added to the primary side of the OBC transformer 402 to modify the Type A topology and improve the flexibility and efficiency of the resonant network design. Moreover, typically in a bidirectional application, a symmetrical topology, as presented here, may be preferred.

[00101] The symmetrical resonant topology shown in FIG. 4B may have the technical effect of improved bidirectional charging applications because the resonant components would behave the same in charging and discharging modes leading to a simplified controller design. Moreover, by having a resonant compensation on the secondary side of the converter, the OBC transformer's 402 secondary side winding leakage inductance can be compensated. Therefore, the reactive current of the battery side inverter can be reduced, which reduces the semiconductor switches current rating and consequently results in lower losses and lower implementation costs. In conventional asymmetric LLC converters, the converter operation range and soft switching range are limited. In contrast, another advantage of having a symmetrical resonant bidirectional converter is the capability of wide voltage range operation and a wide range of soft switching in either power transfer direction. [00102] A non-symmetrical resonant topology can also be used, however it may require additional technical consideration. For example, when the output voltage of the integrated system 300B is low and its output current requirement is high, a high step-down transformer may be used to reduce the output voltage but increase its current. Therefore, the current rating requirements for the passive resonant components may be higher than desired from a commercial or cost perspective. Therefore, it may be beneficial to remove one or all of the passive resonant components and to instead implement a simpler resonant network on the secondary side of the transformer, such as series configuration, or even use a non-resonant topology.

[00103] FIG. 4C shows a circuit diagram 400C of an integrated wireless charger topology with a single-phase WC receiver 326 with an LCC compensation (Type C) within the vehicle assembly, according to some embodiments. The vehicle assembly is understood to be the portion of the vehicle containing both the OBC and WC systems. Further, the OBC enclosure 302 is the portion of the vehicle assembly which contains the transformer 312. Although the series compensation for wireless charging is shown in 400C, in some cases, other topologies such as LCC and LC are preferred. Similarly, the isolation transformer 402 of the OBC system is connected to the intermediate tap 404 of the receiver 326 coil and the second intermediate tap 406 of the DC-link capacitors. However, this results in a resonant topology for OBC which may require more complicated tuning compared to Type A due to the higher order resonant network in FIG. 4C as compared to the resonant network shown in FIG. 4A.

[00104] FIG. 4D shows a circuit diagram 400D of an integrated wireless charger topology with a three-phase WC receiver 326 with a Series compensation and the OBC transformer 402 having a half-bridge (Type D), according to some embodiments. In FIG. 4D, a three-phase wireless charger is integrated with the single-phase OBC transformer 402. A series compensation in Y connection is used; this series compensation is in series with both the WC receiver 326 and OBC transformer 402. One terminal of the OBC transformer 402 is connected to the connection point 408 of the WC receiver coils; the other terminal can be connected to the second intermediate tap 406 of the output DC link capacitors or a half-bridge diode (Type E), as shown in FIG. 4E. [00105] FIG. 4E shows a circuit diagram 400E of an integrated wireless charger topology with a three-phase WC receiver 326 with a Y-Series compensation and OBC transformer 402 having a full-bridge (Type E), according to some embodiments.

[00106] According to the operational principles of FIG. 4E in WC mode (and also FIG. 4D when in WC mode), three phase current with a 120° phase-shift flows through the receiver 326 coils of the wireless charger (i.e. differential mode). Therefore, the sum of the phase currents would be zero and no current will pass through the neutral connection point 408, where the OBC transformer 402 is electrically coupled to. The circuit topology 600A in WC mode and its simplified equivalent single-phase model 600B are shown in FIG. 6A and FIG. 6B, respectively. In FIG. 6B, R_eqA=ReqB=Reqc=QRo/'n², where R_o is the battery equivalent resistance given by Vbat/lbat.

[00107] Similarly, according to the operational principles of FIG. 4E in OBC mode, the secondary side current of the OBC transformer 402 flows through the connection point 408 and along the WC receiver 326 coils in phase (i.e. common mode). The equivalent circuits 600C, 600D of the topology of FIG. 4E in OBC mode is shown in FIG. 6C and FIG. 6D. In FIG. 6D, Req is the equivalent resistance seen before the rectification stage. In OBC mode, the current of each phase is 1/3 of the output current ideally. The magnetic coupler of the receiver 326 should have minimal or zero magnetic flux leakage when the transformer 402 transmits current through the connection point 408 (i.e., when in OBC mode) to ensure the safety of individuals in proximity to the receiver 326. To achieve minimal or zero magnetic flux leakage from the receiver 326 in OBC mode, the receiver 326 may have a symmetrical coil path which cancels out any magnetic field generated by the coil branches.

[00108] FIG. 4F is a circuit diagram 400F of an integrated wireless charger topology with a three-phase WC receiver 326 with a A-Series compensation and OBC transformer 402 having a half-bridge (Type F), according to some embodiments. In this topology, the Y-Series resonant capacitor bank seen in FIG. 4E of the wireless charging system is replaced by a A- Series. By replacing the Y-Series resonant capacitor bank with a A-Series resonant capacitor bank for conversion in three-phase systems, one-third of the required resonant capacitance is required. This configuration may be beneficial when a lower capacitance value is required for the resonant network. [00109] Therefore, the integrated system 300B using a magnetic component such as the receiver 326 coil as the connection point for the current splitting circuit 330 can operate in either OBC or WC mode without any interference with the OBC or WC functionality, or generation of magnetic field leakage. The topology in FIGs. 4A-4F reduces the number of rectifier diodes to six instead of eight in a three-phase wired and wireless charging system (FIGs. 4D-4F), and four instead of eight in a single-phase wired and wireless charging system (i.e., FIGs. 4A-4C). Moreover, the cost associated with the mechanical assembly, heatsink, and PCB are reduced due to the integrated components which are shared between the OBC and WC systems.

[00110] In cases where the intermediate tap 404 of the wireless receiver 326 is used as a connection point between the OBC transformer 402 and WC system, safety standards may be violated if a magnetic field is generated on the WC receiver 326 coil while the integrated system 300B is operating in OBC mode. This magnetic field may be harmful to living objects and cause heating in surrounding metallic objects. The magnetic field emissions may be mitigated by designing the receiver 326 to be symmetrical, and the OBC transformer 402 may be connected to the intermediate tap 404 or connection point 410 (i.e., the neutral center point) of the receiver 326 coils.

[00111] FIG. 4G shows a circuit diagram 400G of an integrated wireless charger topology with a single-phase WC receiver 326 with an LCC compensation, and OBC transformer 402 having a half-bridge (Type G), according to some embodiments. In this configuration, instead of using the neutral point (i.e., intermediate tap 404 or connection point 408) of the magnetic coupler (i.e., receiver 326 coil), a resonant tap 410 positioned on a node located at a symmetrical mid-point of two effective series capacitors, which in this case are capacitors of the resonant network 314 of the VA side, can be used to connect the terminal of the secondary side of the OBC transformer 402. The resonant tap 410 can be applied to two effective series capacitors, inductors, or any impedances/time varying circuit components that are normally used in a resonant circuit. This configuration can be applied to a single-phase or a multi-phase wireless charging receiver 326, as shown in FIGs. 4G and 4H.

[00112] The use of a resonant network for the current splitting circuit 330, rather than a magnetic structure (i.e., a transformer 312 or receiver 326), may reduce the potential for harmful exposure to the magnetic field through leakage into the surrounding environment. If a magnetic structure is used, it may need to be designed symmetrically to ensure that there is minimal leakage of the magnetic field. However, due to the passive elements and the tolerances of the resonant network, current biasing between the two branches of the resonant network is possible, which creates no, or minimal, magnetic field leakage.

[00113] Even if there is asymmetry present in the receiver 326 which may lead to magnetic field leakage, the risk can be further mitigated by disconnecting the receiver 326 from the system during OBC mode operation. In some embodiments, the receiver 326 can be disconnected during OBC mode through relays or any type of active switch electrically coupled between the resonant network 314 and the receiver 326. In another embodiment, a bypass relay may be electrically coupled to the receiver 326 coil to short the receiver coil 326 during OBC mode to avoid any current flowing into the receiver 326 coils.

[00114] Therefore, one operational benefit of using the shared resonant network 314 as the connection point for the current splitting circuit 330 is that minimal to zero magnetic field leakage is produced without sacrificing the efficiency and performance of the resonant network 414. When using the shared resonant network 314 as a connection point for the OBC and WC systems, the operational principles involves dividing a resonant capacitor, or other time varying circuit components, into two elements, and the OBC transformer 402 is connected to the midpoint of these components at a resonant tap 410. This forms a symmetrical circuit for flowing the current from the secondary side of the OBC transformer 402 to the current splitting circuit 330 with no or minimal current passing through the WC receiver 326 coil, and thus, no magnetic field is generated. The current splitting circuit 330 can either be placed proximal to the receiver 326, proximal to the OBC transformer 402, or in the OBC system 302 enclosure, depending on the application requirements. However, the current splitting circuit 330 can be placed anywhere which can improve the system packaging, assembly complexity and/or reduce manufacturing costs. In some embodiments, the current splitting circuit 330 is located within noise and temperature controlled enclosure to reduce interference with the circuit performance. In some embodiments, it may be desirable to house the current splitting circuit 330 proximal to the OBC transformer 402 to reduce the risk that current will be induced within the receiver 326 coils by the proximal circuitry. [00115] In some embodiments, the current splitting circuit 330 can use the OBC transformer 402 as the connection point for the integrated system 300B. In this embodiment, the intermediate tap 404 is located on the secondary or primary side of the transformer 402. The general operation principles discussed for the embodiments shown in 400A, 400B and 400C would apply to the embodiment where the transformer 402 is used for the intermediate tap 404. This embodiment may be desirable when the receiver 326 coil is not symmetrical or otherwise unable to mitigate generation of magnetic field leakage during OBC mode.

[00116] FIG. 4H shows a circuit diagram 400H of an integrated wireless charger topology with a three-phase WC receiver 326 with a Y-Parallel compensation and OBC transformer 402 having a half-bridge (Type H), according to some embodiments. The system shown in 400H has a technical benefit of not requiring an alteration to the electrical structure of the receiver 326. Further, the electrical cables connecting the OBC transformer 402 and WC receiver 326 can be shorter, due for example to the compact nature of the shared resonant network 314, which may reduce interference within the circuit and reduce structural costs as compared to conventional systems such as that seen in FIG. 3A. Additionally, the shared resonant network 314 minimizes the current going to the wireless receiver 326 coils in OBC mode due to the neutral placement of the resonant tap 410. This design can also be expanded to accommodate more phases or single-phase wireless charging receivers 326. In some embodiments, the compensation network of the wireless receiver 326 can be a simple series, parallel, or an LCC type resonant network. The simplified 700A and single-phase equivalent circuits 700B of this topology in WC mode is shown in FIGs. 7A-7B. The simplified 700C and single-phase equivalent circuits 700D of this topology in OBC mode is shown in FIGs. 7C-7D. According to the operational principles of FIG. 4H, in WC mode shown in FIGs. 7A-7B, three phase current with a 120° phase-shift flows through the receiver 326 coils of the wireless charger (i.e. differential mode).

[00117] The use of a resonant network for the current splitting circuit 330, rather than a magnetic structure (i.e., a transformer 312 or receiver 326), may reduce the potential for harmful exposure to the magnetic field through leakage into the surrounding environment. If a magnetic structure is used, it may need to be designed symmetrically to ensure that there is minimal leakage of the magnetic field. However, due to the passive elements and the tolerances of the resonant network, current biasing between the two branches of the resonant network is possible, which creates no, or minimal, magnetic field leakage.

[00118] Even if there is asymmetry present in the receiver 326 which may lead to magnetic field leakage, the risk can be further mitigated by disconnecting the receiver 326 from the system during OBC mode operation. In some embodiments, the receiver 326 can be disconnected during OBC mode through relays or any type of active switch electrically coupled between the resonant network 314 and the receiver 326. In another embodiment, a bypass relay may be electrically coupled to the receiver 326 coil to short the receiver coil 326 during OBC mode to avoid any current flowing into the receiver 326 coils.

[00119] Therefore, one operational benefit of using the shared resonant network 314 as the connection point for the current splitting circuit 330 is that minimal to zero magnetic field leakage is produced without sacrificing the efficiency and performance of the resonant network 414. When using the shared resonant network 314 as a connection point for the OBC and WC systems, the operational principles involves dividing a resonant capacitor, or other time varying circuit components, into two elements, and the OBC transformer 402 is connected to the midpoint of these components at a resonant tap 410. This forms a symmetrical circuit for flowing the current from the secondary side of the OBC transformer 402 to the current splitting circuit 330 with no or minimal current passing through the WC receiver 326 coil, and thus, no magnetic field is generated. The current splitting circuit 330 can either be placed proximal to the receiver 326, proximal to the OBC transformer 402, or in the OBC system 302 enclosure, depending on the application requirements. However, the current splitting circuit 330 can be placed anywhere which can improve the system packaging, assembly complexity and/or reduce manufacturing costs. In some embodiments, the current splitting circuit 330 is located within noise and temperature controlled enclosure to reduce interference with the circuit performance. In some embodiments, it may be desirable to house the current splitting circuit 330 proximal to the OBC transformer 402 to reduce the risk that current will be induced within the receiver 326 coils by the proximal circuitry.

[00120] FIG. 4I shows a circuit diagram 400I of an integrated wireless charging system where the wireless receiver 326 is a single-phase coil, and the OBC transformer 402 is a singlephase transformer coupled to a single-phase full-bridge inverter. The secondary side of the winding of the OBC transformer 402 is connected to the second intermediate tap 406 of the output DC link and a resonant tap 410 on the resonant network. In this embodiment, the connection point of the OBC and WC system (i.e., resonant tap 410) is between the resonant capacitor and the diode bridge. In some embodiments, the capacitor 2C_r can be built using two capacitors in series and the resonant tap 410 can be located between a mid-point of the two series capacitors.

[00121] In a potential variant embodiment, the current splitting circuit 330 can use the OBC transformer 402 as the connection point for the integrated system 300B. In this embodiment, the intermediate tap 404 is located on the secondary or primary side of the transformer 402. The general operation principles discussed for the embodiments shown in 400A, 400B and 400C would apply to the embodiment where the transformer 402 is used for the intermediate tap 404. This embodiment may be desirable when the receiver 326 coil is not symmetrical or otherwise unable to mitigate generation of magnetic field leakage during OBC mode.

[00122] Simulation Results

[00123] A few examples of the proposed integrated system 300B are studied in this section. A principle of operation of the presented embodiments is that the integrated system 300B should offer a decoupled behavior for each of the WC and OBC modes such that neither charging mode negatively influences the opposing charging mode or creates safety concerns. For example, the proposed embodiments all provide protection against magnetic field leakage generated by the receiver 326 during OBC mode, either by having the resonant network configured as the connection point of the current splitting network 330, or by implementing a symmetrical receiver 326 coil layout which uses overlapping coil branches to cancel out magnetic field leakage from the coil branches.

[00124] Two scenarios were considered to study the operation of the proposed integration system and method. It should be noted that the WC system is controlled by changing the input DC link voltage and the OBC system is controlled by changing its inverter phase-shift. However, other control methods can be used to regulate the output current. For example, dutycycle control, frequency sweep control and the like. [00125] Single-phase wireless chargers may be more suitable for lower power levels. Therefore, the power level was limited to 6.6 kW for this case. The wireless charging system 300B operated at 85 kHz (according to SAE2954). The wireless charging receiver 326 was a rectangular type with a dimension of 640x508 mm². Ferrite blocks were placed underneath the transmitter coil to reduce magnetic field leakage and improve the efficiency of the system. As an example, the Type A topology seen in FIG. 4A is simulated, and the results are presented below. In this simulation, the nominal voltage of the battery is 350 V, and the nominal current is 18 A. FIGs. 8A and 8B show the simulation results in OBC and WC modes, respectively.

[00126] According to FIG. 8A, when the system is in WC mode, no current flows in the OBC transformer winding as expected (ls«0). When the system is operating in OBC mode, the current of the receiver coil is half of the OBC transformer current as expected (see FIG. 8B). If the magnetic coupler (i.e. , the wireless receiver) is designed symmetrically, the sum of the magnetic fields would be zero. Therefore, it can be concluded that the wireless charger and onboard charger can operate without any interference with each other.

[00127] A wireless charger with three phases is generally more appropriate for high-power applications. The onboard charger power is usually around 6.6 kW or 11 kW. For this simulation, the WC and OBC were designed with a nominal power of 50 kW and 6.6 kW, respectively. The simulation results in WC and OBC modes for a current splitting circuit 330 using the receiver 326 as the connection point for the current splitting circuit 330 are presented in FIGs. 9A and 9B, respectively. It can be seen that while the system is working in WC mode, the receiver 326 coil currents are balanced with 120 degrees of phase difference. In this case, the OBC transformer 402 secondary side current, /_s, is almost zero due to symmetry of the circuit.

[00128] Similarly, while the system is operating in OBC mode, the receiver 326 currents are one-third of the transformer secondary side current, as expected. Assuming the magnetic coupler (i.e., the wireless receiver 326) is symmetrical such that the sum of the magnetic field is minimal, the system can safely operate in both OBC and WC modes without any interference. [00129] The integrated system may be suitable for autonomous vehicles and electric vehicles with high power ratings. When used for an autonomous vehicle, such as a taxi, passenger vehicles, vacuum cleaner, arial drone, etc., the primary basis of charging will be the WC mode, allowing the autonomous vehicle to return to a charging station after the battery has been depleted below a pre-determined threshold. However, due to the integration of the OBC within the system, an autonomous vehicle would have the ability to receive a charge from a mechanically connected charging source (i.e. through a terminal) if it was incapable of returning to the charging station.

[00130] When used for an electric vehicle with a power rating above most consumer vehicles, such as a bus, transport vehicles, cranes, forklifts, or other vehicles used in shipping and warehouse operations, the use of the full bridge rectifier along with the voltage splitting within the integrated system allows the WC mode to transfer a high voltage source which thereby reduces downtime and allows the vehicles to return to operation with a full charge in a relatively short amount of time. For example, in a warehouse setting, ground charging stations could be placed at common locations at which vehicles (forklifts, cranes, transport trucks) are typically required to spend large amounts of times (loading docks, common pathways) such that the vehicles could be charged as it operates. In another example, in a transport setting, ground charging stations could be located along common shipping routes such that vehicles could be charged either as they drive along the route (i.e. the ground charging stations are under the road) or at major stopping points (i.e. off ramp locations).

[00131] In some circumstances, it is preferable to use OBC mode for charging, even if it would be possible to return to a charging station. For example, when the vehicle battery has reached below a minimum threshold, such as 30% charge, it may be preferable to use the OBC mode in order to preserve battery health due to the potential damage which can be caused by exposing the depleted battery to the higher power provided in WC mode.

[00132] In other circumstances, while WC mode may be preferred, there may be an urgent need for charging through OBC mode. For example, if an electric vehicle is unable to return to a ground charging station prior to the battery being completely or substantially depleted, the electric vehicle may be able to have a power source brought to its location (such as a portable generator) which can charge the electric vehicle in OBC mode such that the battery is returned to a power level sufficient to arrive at a ground charging station to receive the remaining charge through a WC.

[00133] As can be seen from the above examples, the integrated system is designed for the WC mode to be the primary charging method. The high voltage which is capable of being provided by the integrated system in WC mode allows for more efficient and timely charging without the need to have a person present at the time of charging to connect physical terminals. However, the integrated circuit provides the possibility of OBC mode at a reduced cost and complexity, due to the shared components, which can be used as a fail safe if an electric vehicle would otherwise be unable to reach a ground charging station.

[00134] The wireless charging mode may be compatible with any standard ground assembly 320 for wireless charging, allowing the proposed integrated system to be used across varying geographic areas and industry sectors.

[00135] While it may be desirable, in a situation when there is a significant benefit which would be provided by charging the battery in minimal time, to use both the WC and OBC charger simultaneously, this mode of operation typically does not operate effectively and is not desirable due to the risk of potentially going beyond the power rating of the components.

[00136] Applicant notes that the described embodiments and examples are illustrative and non-limiting. Practical implementation of the features may incorporate a combination of some or all of the aspects, and features described herein should not be taken as indications of future or existing product plans. Applicant partakes in both foundational and applied research, and in some cases, the features described are developed on an exploratory basis.

[00137] 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).

[00138] 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.

[00139] 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 presented embodiments are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. [00140] As can be understood, the examples described above and illustrated are intended to be exemplary only.

Claims

WHAT IS CLAIMED IS:

1. An integrated charging system for an electric vehicle capable of transferring power wirelessly and through direct charging, the system comprising: a first power source within a wireless ground assembly, the first power source is electrically coupled to a wireless transmitter, the wireless transmitter containing at least one coil for producing a magnetic field; a second power source electrically coupled to a transformer located within an enclosure; a current splitting device containing at least the transformer, a wireless receiver and a shared resonant network, the wireless receiver having at least one coil which receives an induced current from the magnetic field of the wireless transmitter when aligned with the at least one wireless transmitter coil, and the resonant network electrically coupled to each of the at least one coil of the wireless receiver; a shared rectifier electrically coupled to the resonant network and an energy storage device, the energy storage device configured to store power received from at least one of the wireless transmitter and transformer; and a first connection point and a second connection point of the current splitting device, the first connection point located at a node on one of the wireless receiver and resonant network, the second connection point connected in parallel with the shared rectifier, and the transformer having an electrical coupling to the first connection point and second connection point for transferring current through the current splitting circuit; wherein the first connection point taps into one of the wireless receiver and resonant network at a neutral point which splits into two or more symmetrical electrical paths for the current to flow to the energy storage device.

2. The integrated charging system of claim 1 , wherein the first connection point is located on the resonant network.

3. The integrated charging system of claim 2, wherein the resonant network has at least two time varying circuit components, and the first connection point is placed at a symmetrical point of the resonant network between the at least two time varying circuit components.

4. The integrated charging system of claim 1 , wherein the first connection point is located on the wireless receiver.

5. The integrated charging system of claim 4, wherein the wireless receiver comprises two or more coils, and the first connection point is placed at a symmetrical point between the two or more coils.

6. The integrated charging system of any one of claims 3 or 5, wherein the wireless receiver is one of a uni-polar, multi-polar, circular, rectangular and double-D coil structure.

7. The integrated charging system of any one of claims 3 or 5, wherein the resonant network is any one of a series, LLC, Y-series and A-series compensation.

8. The integrated charging system of claim 3, wherein the current splitting circuit is located proximal to the transformer.

9. The integrated charging system of claim 8, wherein the current splitting circuit is located inside the enclosure.

10. The integrated charging system of any one of claims 3 or 5, wherein the shared rectifier is a full bridge rectifier.

11. The integrated charging system of claim 1 , wherein the energy storage device is a battery, and the battery, wireless receiver, resonant network, shared rectifier and transformer are housed in a shared charging assembly within an electric vehicle assembly.

12. The integrated charging system of claim 1 , wherein the shared charging assembly contains shared physical components comprising at least one of an enclosure, printed circuit boards, connectors, contacts, heatsinks, thermal pads, cold plate, and cables.

13. The integrated charging system of claim 1 , wherein each of the at least one coil of the wireless receiver is coupled to the resonant network through an active switching component.

14. The integrated charging system of claim 13, further comprising a controller coupled to the active switching component, the controller modulating the active switches to disconnect the wireless receiver when the transformer is receiving current from the second power source.

15. The integrated charging system of claim 1 , wherein the transformer is directly coupled to the first connection point.

16. The integrated charging system of claim 1 , wherein a fuse is coupled between the first connection point and the transformer to permit bi-directional charging.

17. The integrated charging system of claim 1 , wherein a compensation capacitor is coupled between the first connection point and the transformer to permit bi-directional charging.

18. The integrated charging system of claim 1 , wherein the second power source is a portable generator or high-capacity battery.

19. A drivetrain comprising the system of any one of claims 1-18.

20. An electric vehicle comprising the drivetrain of claim 19.

21 . A method for integrated charging of an electric vehicle capable of being charged through wireless and direct charging, the method comprising: generating a magnetic field through at least one coil of a transmitter within a wireless ground assembly when the wireless transmitter is receiving power from a first power source; generating an output of current from a transformer located within an enclosure when the transformer is receiving power from a second power source; providing a current splitting device containing at least the transformer, a wireless receiver and a shared resonant network, and the wireless receiver having at least one coil which receives an induced current from the magnetic field of the wireless transmitter when aligned with the at least one wireless transmitter coil, and the resonant network electrically coupled to each of the at least one coil of the wireless receiver; and coupling a shared rectifier to the resonant network and an energy storage device, the energy storage device storing power transmitted from at least one of the wireless transmitter and transformer; wherein the current splitting device has a first connection point and a second connection point, the first connection point located at a node on one of the wireless receiver and resonant network, the second connection point connected in parallel with the shared rectifier, and the transformer having an electrical coupling to the first connection point and second connection point for transferring current through the current splitting circuit; wherein the first connection point taps into one of the wireless receiver and resonant network at a neutral point which splits into two or more symmetrical electrical paths for the current to flow to the energy storage device.

22. The method of claim 21 , wherein the first connection point is located on the resonant network.

23. The method of claim 22, wherein the resonant network has at least two time varying circuit components, and the first connection point is placed at a symmetrical point of the resonant network between the at least two time varying circuit components.

24. The method of claim 21 , wherein the first connection point is located on the wireless receiver.

25. The method of claim 24, wherein the wireless receiver comprises two or more coils, and the first connection point is placed at a symmetrical point between the two or more coils.

26. The method of any one of claims 23 or 25, wherein the wireless receiver is one of a unipolar, multi-polar, circular, rectangular and double-D coil structure.

27. The method of any one of claims 23 or 25, wherein the resonant network is any one of a series, LLC, Y-series and A-series compensation.

28. The method of claim 23, wherein the current splitting circuit is located proximal to the transformer.

29. The method of claim 28, wherein the current splitting circuit is located inside the enclosure.

30. The method of claim 21 , wherein the shared rectifier is a full bridge rectifier.

31 . The method of claim 21 , wherein the energy storage device is a battery, and the battery, wireless receiver, resonant network, shared rectifier and transformer are housed in a shared charging assembly within an electric vehicle assembly.

32. The method of claim 21 , wherein the shared charging assembly contains shared physical components comprising at least one of an enclosure, printed circuit boards, connectors, contacts, heatsinks, thermal pads, cold plate, and cables.

33. The method of claim 21 , wherein each of the at least one coil of the wireless receiver is coupled to the resonant network through an active switching component.

34. The method of claim 33, further comprising controlling the active switching component to disconnect the wireless receiver when the transformer is receiving current from the second power source.

35. The method of claim 21 , wherein the transformer is directly coupled to the first connection point.

36. The method of claim 21 , wherein a fuse is coupled between the first connection point and the transformer to permit bi-directional charging.

37. The method of claim 21 , wherein a compensation capacitor is coupled between the first connection point and the transformer to permit bi-directional charging.

38. The method of claim 21 , wherein the second power source is a portable generator or high capacity battery.

39. A drivetrain configured using the method of any one of claims 21-38.

40. An electric vehicle comprising the drivetrain of claim 39.

41. A non-transitory computer 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 21-38.