Magnetic core structure for wireless power transmission, and wireless power transmission device and method using magnetic core structure

Abstract

A magnetic core structure provided with a primary coil for wireless power transfer (WPT) includes: a first structure having a structure extending in a first axial direction and protruding therefrom in a first region including a center of the primary coil; a second structure spaced apart from the first structure in a second axial direction, the second structure having a structure extending in the first axial direction and protruding therefrom; and a support structure having the same magnetic characteristics as the first structure and the second structure, and supporting the first structure and the second structure.

Description

Technical Field

[0001] The present disclosure relates to a magnetic core structure provided with a coil of a device for wireless power transmission (WPT). More specifically, the present disclosure relates to a magnetic core structure that increases the degree of freedom of power transmission range and the coil alignment of a power transmission coil and a power receiving coil, and a wireless power transmission device and method using the magnetic core structure. Background Art

[0002] An electric vehicle (EV) is driven by an electric motor through electricity stored in a battery, and generates less pollution, such as exhaust gas and noise, and has advantages of less malfunction, longer life, and simplified driving operation than a conventional gasoline engine vehicle.

[0003] EVs can be classified into hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicles (EVs) based on the driving power source. HEVs have an engine as a main power source and an electric motor as an auxiliary power source. PHEVs have an electric motor and a battery as a main power source and an engine used when the battery is discharged. EVs have an electric motor but no engine.

[0004] An electric vehicle charging system may be defined as a system for charging a battery installed in an electric vehicle using power obtained from a commercial power grid or stored in an energy storage device. Such an electric vehicle charging system may have various forms depending on the type of electric vehicle. For example, an electric vehicle charging system may include a conductive charging system using a cable or a contactless wireless power transmission system.

[0005] During a charging session, a receiving plate of a vehicle assembly (VA) mounted on an electric vehicle can form an inductive resonant coupling with a transmitting plate of a ground assembly (GA) mounted at a charging station or charging point, and the battery of the EV can be charged using power transmitted from the ground assembly through the inductive resonant coupling.

[0006] Meanwhile, the structure of the transmission plate and the receiving plate may be a key factor for ensuring high power transmission efficiency in a magnetic resonance type wireless power transmission system. Specifically, in a typical configuration of a transmission plate or a receiving plate including a ferrite structure for facilitating wireless power transmission and a coil wound around the ferrite structure, the power transmission efficiency may vary depending on the ferrite structure and / or the coil structure.

[0007] Therefore, there is a need for a magnetic core structure that can improve power transmission efficiency in a wireless power transmission system. Summary of the invention

[0008] Technical issues

[0009] Inductive wireless power transfer can be achieved by the arrangement of a very simple structure, but a technology is required that can enhance the degree of freedom in the power transfer range and the coil alignment between the transmitting coil / primary coil and the receiving coil / secondary coil.

[0010] In order to solve the above problems, an object of the present disclosure is to provide a magnetic structure that achieves efficient power transmission in an inductive wireless power transmission system for electric vehicles by reducing performance degradation caused by deviation in power transmission distance between primary and secondary coils and alignment between coils.

[0011] Another object of the present disclosure is to provide a magnetic structure that enhances the degree of freedom of power transmission distance between a primary coil and a secondary coil and an alignment position of the secondary coil relative to the primary coil.

[0012] Another object of the present disclosure is to provide a magnetic structure equipped with a magnetic core having two wall-like structures in a space surrounded by a primary coil, thereby adjusting the mutual inductance of the primary coil and the secondary coil and the coupling coefficient between the coils and improving the power transmission efficiency in a misaligned state.

[0013] Another object of the present disclosure is to provide a magnetic structure, wherein a magnetic core having a wall-like structure is arranged at a maximum available misalignment position to increase the coupling coefficient at the misalignment position without reducing the coupling coefficient at the alignment position, thereby improving the power transmission efficiency at each misalignment position within the maximum available misalignment range.

[0014] Another object of the present disclosure is to provide a wireless power transmission (WPT) device having an optimized arrangement of a novel magnetic core structure and exhibiting enhanced power transmission efficiency, and a wireless power transmission method using the wireless power transmission device.

[0015] Technical Solution

[0016] According to aspects of an exemplary embodiment for achieving the purpose, a magnetic core structure provided with a primary coil for wireless power transmission (WPT) may include: a first structure configured to protrude in a first space including a center of the primary coil and to extend in a first axis direction; a second structure spaced apart from the first structure in a second axis direction and configured to protrude in the same direction as the first structure and to extend in the first axis direction; and a supporting structure configured to support the first structure and the second structure and having the same magnetic properties as the first structure and the second structure.

[0017] The first structure and the second structure may be arranged such that a spacing distance between the first structure and the second structure is maximized within the first space.

[0018] The first structure and the second structure may be arranged symmetrically with respect to a center of the primary coil.

[0019] The first structure and the second structure may be configured to protrude in the third axis direction by more than a first reference value.

[0020] The first reference value may be 50 mm.

[0021] The first and second structures may have widths greater than or equal to a second reference value in the second-axis direction.

[0022] The second reference value may be 25 mm.

[0023] Alternatively, the second reference value may be 50 mm.

[0024] The primary coil may be arranged to surround the first structure and the second structure. The primary coil may include a primary coil wire wound by one or more turns. The primary coil wire may have a predetermined height in the third axis direction. The predetermined height may be a uniform height.

[0025] The primary coil may be arranged to surround the first structure and the second structure. The primary coil may include a primary coil wire wound by one or more turns. The turns of the primary coil wire may be positioned higher in the third axis direction as they are closer to the center of the primary coil.

[0026] The primary coil may be arranged to surround the first structure and the second structure. The primary coil may include a primary coil wire wound by one or more turns. The closer to the center of the primary coil, the lower the turn of the primary coil wire may be positioned in the third axis direction.

[0027] According to another aspect of the exemplary embodiment, a wireless power transmission device configured to wirelessly transmit power to a receiving plate including a secondary coil includes: a primary coil; a first magnetic structure configured to protrude in a first space including a center of the primary coil and extend in a first axial direction; a second magnetic structure spaced apart from the first magnetic structure in a second axial direction and configured to protrude in the same direction as the first magnetic structure and extend in the first axial direction; a supporting magnetic structure configured to support the first magnetic structure and the second magnetic structure and having the same magnetic properties as the first magnetic structure and the second magnetic structure; and a shell configured to support the primary coil, the first magnetic structure, the second magnetic structure and the supporting magnetic structure.

[0028] The first magnetic structure and the second magnetic structure may be arranged such that a separation distance between the first magnetic structure and the second magnetic structure is maximized within the first space.

[0029] The first magnetic structure and the second magnetic structure may be arranged symmetrically with respect to a center of the primary coil.

[0030] The first magnetic structure and the second magnetic structure may be configured to protrude in the third axis direction by more than a first reference value.

[0031] The first magnetic structure and the second magnetic structure may have a width greater than or equal to a second reference value in the second-axis direction.

[0032] According to another aspect of an exemplary embodiment, a method for wirelessly transmitting power from a transmission board including a primary coil to a receiving board including a secondary coil includes: setting a magnetic core structure, the magnetic core structure including: a first magnetic structure, configured to protrude within a first space including a center of the primary coil and extend in a first axial direction; and a second magnetic structure, spaced apart from the first magnetic structure in a second axial direction and configured to protrude in the same direction as the first magnetic structure and extend in the first axial direction; positioning the center of the secondary coil within a predetermined offset range from the center of the primary coil; and supplying input power to the primary coil, and wirelessly transmitting the input power to the secondary coil.

[0033] The first magnetic structure and the second magnetic structure may be configured to protrude in the third axis direction by more than a first reference value.

[0034] The method may further include: providing a primary coil surrounding the first magnetic structure and the second magnetic structure, wherein the primary coil includes a primary coil wire wound by one or more turns having a predetermined height in the third axis direction. The predetermined height may be a uniform height.

[0035] The method may further include providing a primary coil surrounding the first magnetic structure and the second magnetic structure, wherein the primary coil includes a primary coil wire wound by one or more turns, wherein the turns of the primary coil wire are positioned higher in the third axis direction as they are closer to the center of the primary coil.

[0036] The method may further include providing a primary coil surrounding the first magnetic structure and the second magnetic structure, wherein the primary coil includes a primary coil wire wound by one or more turns, wherein the turns of the primary coil wire are positioned lower in the third axis direction as they are closer to the center of the primary coil.

[0037] Beneficial Effects

[0038] According to an exemplary embodiment of the present disclosure, a magnetic structure is provided that enables efficient power transmission in an inductive wireless power transmission system for electric vehicles by reducing performance degradation that may be caused by deviation in power transmission distance between primary and secondary coils and alignment between coils.

[0039] According to an exemplary embodiment of the present disclosure, there is provided a magnetic structure that enhances the degree of freedom of a power transmission distance between a primary coil and a secondary coil and an alignment position of the secondary coil relative to the primary coil.

[0040] According to an exemplary embodiment of the present disclosure, a magnetic structure is provided, which is equipped with a magnetic core having two wall-like structures in a space surrounded by a primary coil, thereby adjusting the mutual inductance of the primary coil and the secondary coil and the coupling coefficient between the coils and improving the power transmission efficiency in a misaligned state.

[0041] According to an exemplary embodiment of the present disclosure, a magnetic structure is provided, wherein a magnetic core having a wall-like structure is arranged at a maximum available misalignment position to increase a coupling coefficient at the misalignment position without reducing the coupling coefficient at the alignment position, thereby improving power transmission efficiency at each misalignment position within the maximum available misalignment range.

[0042] According to exemplary embodiments of the present invention, a wireless power transmission (WPT) device having an optimized arrangement of a novel magnetic core structure and exhibiting enhanced power transmission efficiency, and a wireless power transmission method using the wireless power transmission device are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a schematic diagram of a wireless power transmission system to which an exemplary embodiment of the present disclosure can be applied;

[0044] Figure 2 is a circuit diagram of an equivalent circuit of an electric vehicle wireless charging circuit according to an exemplary embodiment of the present disclosure;

[0045] Figure 3 An equivalent circuit of a single-phase to single-phase wireless power transmission (WPT) system according to an exemplary embodiment of the present disclosure is shown;

[0046] Figure 4 are conceptual cross-sectional and front views of a conventional power transmission plate which may be a comparative example of the present disclosure;

[0047] Figure 5 is a perspective view showing a power transmission board and a power receiving board including a magnetic core structure according to an exemplary embodiment of the present disclosure;

[0048] Figure 6 are front and side views showing a power transmission board and a power reception board including a magnetic core structure according to an exemplary embodiment of the present disclosure;

[0049] Figure 7 is a conceptual plan view showing a power transmission board and a power reception board including a magnetic core structure according to an exemplary embodiment of the present disclosure;

[0050] Figure 8 is a perspective view showing a power transmission board and a power receiving board including a magnetic core structure according to another exemplary embodiment of the present disclosure;

[0051] Fig. 9 are front and side views showing a power transmission board and a power receiving board including a magnetic core structure according to another exemplary embodiment of the present disclosure;

[0052] Fig.10 is a perspective view showing a power transmission board and a power receiving board including a magnetic core structure according to still another exemplary embodiment of the present disclosure;

[0053] Fig.11 are front and side views showing a power transmission board and a power receiving board including a magnetic core structure according to still another exemplary embodiment of the present disclosure;

[0054] Fig.12 is a flowchart conceptually illustrating a wireless power transmission method according to another exemplary embodiment of the present disclosure; and

[0055] Fig.13 is a block diagram showing a general configuration of hardware included in or associated with a wireless power transmission board and / or a wireless power reception board to control a sequence for wireless power transmission. DETAILED DESCRIPTION

[0056] In order to more clearly understand the features and advantages of the present disclosure, the exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, it should be understood that the present disclosure is not limited to the specific embodiments disclosed herein, but includes all modifications, equivalents and substitutions that fall within the spirit and scope of the present disclosure. In the accompanying drawings, similar or corresponding parts can be represented by the same or similar reference numerals.

[0057] Terms including ordinal numbers (such as "first" and "second") designated in this specification for explaining various components are used to distinguish components from other components, but are not intended to be limited to specific components. For example, a second component may be referred to as a first component, and similarly, a first component may be referred to as a second component without departing from the scope of the present disclosure. As used herein, the term "and / or" may include the presence of one or more associated listed items and any and all combinations of listed items.

[0058] In the description of the exemplary embodiments of the present disclosure, “at least one of A and B” may mean “at least one of A or B” or “at least one of a combination of one or more of A and B”. Furthermore, in the description of the exemplary embodiments of the present disclosure, “one or more of A and B” may mean “one or more of A or B” or “one or more of a combination of one or more of A and B”.

[0059] When a component is referred to as being "connected" or "coupled" to another component, the component may be directly logically or physically connected or coupled to the other component or indirectly connected through an intervening object. In contrast, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that there are no intervening objects between the components. Other words used to describe relationships between elements should be interpreted in a similar manner.

[0060] These terms are used herein only for the purpose of describing specific exemplary embodiments and are not intended to limit the present disclosure. Unless the context clearly dictates otherwise, singular forms also include plural referents. Moreover, the expressions "comprises," "comprising," "constructed," and "configured" are used to refer to the presence of the described features, quantities, processing steps, operations, elements, or combinations of parts, but are not intended to exclude the presence or addition of another feature, quantity, processing step, operation, element, or part.

[0061] Unless otherwise defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. These terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant documents, and will not be interpreted as having an ideal or overly formal meaning unless explicitly defined in this application.

[0062] Meanwhile, if necessary, one or more conventional components may be included in the configuration of the present disclosure, and such components will be described herein to the extent that the technical concept and concept of the present disclosure are not obscured. However, if the description of conventional components obscures the technical concept and concept of the present disclosure, the detailed description of these components may be omitted for simplicity.

[0063] The terms used in this disclosure are defined as follows.

[0064] “Electric Vehicle (EV)”: An automobile, as defined in 49 CFR 523.3, intended for highway use, powered by an electric motor that draws current from an on-board energy storage device (such as a battery) that can be recharged from an off-vehicle source (such as residential or utility electric service or an on-board fuel generator).

[0065] EV may include electric vehicles, electric vehicles, electric road vehicles (ERV), plug-in vehicles (PV), electric vehicles (xEV), etc., and xEV may be classified into plug-in full electric vehicles (BEV), battery electric vehicles, plug-in electric vehicles (PEV), hybrid electric vehicles (HEV), hybrid plug-in electric vehicles (HPEV), plug-in hybrid electric vehicles (PHEV), etc.

[0066] “Plug-in Electric Vehicle (PEV)”: An electric vehicle that recharges its on-board main battery by connecting to the electrical grid.

[0067] “Plug-in Vehicle (PV)”: An electric vehicle that is rechargeable from Electric Vehicle Supply Equipment (EVSE) via wireless charging, without the use of a physical plug or physical outlet.

[0068] “Heavy Duty Vehicle (HD Vehicle)”: Any vehicle with more than four wheels as defined in 49 CFR 523.6 or 49 CFR 37.3 (buses).

[0069] “Light plug-in electric vehicle”: a three- or four-wheeled vehicle propelled by an electric motor that draws electric current from a rechargeable battery or other energy device, intended primarily for use on public streets, roads, and highways, and having a rated gross vehicle weight of less than 4,545 kg.

[0070] “Wireless Power Charging System (WCS)”: A system for interactive wireless power transfer and control, the interaction including operations for alignment and communication between a supply device (or ground component) and an EV device (or vehicle component).

[0071] “Wireless Power Transfer (WPT)”: The transmission of power between power sources such as utilities, grids, energy storage devices, fuel cell generators, and EVs through contactless channels such as electromagnetic induction and resonance.

[0072] "Utility": A group of systems that supply electrical energy and include Customer Information Systems (CIS), Advanced Metering Infrastructure (AMI), rate and revenue systems, etc. Utilities can provide energy to EVs through rate schedules and discrete events. In addition, utilities can provide information related to EV certification, intervals for electricity consumption measurement, and tariffs.

[0073] “Smart Charging”: A system in which the EVSE and / or EV (including PEV or PHEV) communicate with the grid to optimize the charging rate or discharging rate of the EV by reflecting the capacity or usage charges of the grid.

[0074] “Automatic charging”: The process of automatically performing inductive charging after the vehicle is in the appropriate position corresponding to the main charger component, which can transfer power by conductive or inductive charging. Automatic charging can be performed after obtaining the necessary certifications and permissions.

[0075] "Interoperability": A state in which components of a system communicate with corresponding components of the system to perform operations targeted by the system. In addition, information interoperability may refer to the ability of two or more networks, systems, devices, applications, or components to effectively share and easily use information without causing inconvenience to users.

[0076] "Inductive Charging System": A system that transfers energy from a power source to an EV via a two-part gapped core transformer, wherein the two halves of the transformer (i.e., the primary coil and the secondary coil) are physically separated from each other. In the present disclosure, an inductive charging system may correspond to an EV power transfer system.

[0077] “Inductive Coupler”: A transformer formed by a primary coil or ground assembly (GA) in the primary device and a secondary coil or vehicle assembly (VA) in the secondary device, which allows the transfer of power across electrical insulation.

[0078] “Inductive coupling”: Magnetic coupling between two coils. One of the two coils may be referred to as the primary coil or GA coil, and the other of the two coils may be referred to as the secondary coil or vehicle component VA coil.

[0079] "Power Supply Circuit (SPC)" or "Ground Assembly (GA)": A component arranged on the infrastructure side of the primary device or ground assembly or including a primary coil (or GA coil) and other components. Other components may include at least one component for controlling impedance and resonant frequency, ferrites implementing a magnetic circuit, and electromagnetic shielding materials. For example, the SPC or GA may include a power / frequency conversion unit and an SPC controller (or GA controller) required to be used as a power source for a wireless power charging system, wiring from the power grid, and wiring between each unit, filtering circuits, and housings.

[0080] "EV Power Circuit (EVPC)" or "Vehicle Assembly (VA)": A component mounted on a vehicle that includes a secondary coil (or VA coil) and other components. Other components may include at least one component for controlling impedance and resonant frequency, ferrites implementing a magnetic circuit, and electromagnetic shielding materials. For example, an EVPC or VA may include a power / frequency conversion unit and an EVPC controller (or VA controller) required as a vehicle assembly for a wireless power charging system, wiring to the vehicle battery, and wiring between each unit, filtering circuits, and housings.

[0081] The SPC may be referred to as or identified by a ground assembly (GA), etc. Similarly, the EVPC may be referred to as or identified by a vehicle assembly (VA), etc.

[0082] GA may be referred to as a primary device, etc., and VA may be referred to as an EV device, a secondary device, etc.

[0083] GA may be referred to as a supply device, a power-side device, or the like, and VA may be referred to as an EV device, an EV-side device, or the like.

[0084] "Primary device": a device that is provided for contactless coupling with a secondary device. In other words, the primary device may be a device external to the EV. When the EV is receiving power, the primary device may operate as a source of power to be transferred. The primary device may include the housing and all covers.

[0085] “Secondary device”: A device mounted on an EV that is configured to be contactlessly coupled with a primary device. In other words, a secondary device may be provided within an EV. When the EV is receiving power, the secondary device may transfer power from the primary device to the EV. The secondary device may include a housing and all covers.

[0086] "Power supply electronics" refers to the portion of the SPC or GA that adjusts the output power level of the primary coil (or GA coil) based on information from the vehicle. "EV power electronics" refers to the portion of the EVPC or VA that monitors specific on-board parameters during charging and initiates communication with the EVPC or GA to facilitate adjustment of the output power level.

[0087] The power supply electronics may be referred to as GA electronics, GA controller, or primary device communications controller (PDCC), and the EV power supply electronics may be referred to as VA electronics, VA controller, or electric vehicle communications controller (EVCC).

[0088] "Magnetic Gap": The vertical distance between the plane of the higher of the top of the Litz wire or the top of the magnetic material in the Primary / GA Coil and the plane of the lower of the bottom of the Litz wire or the bottom of the magnetic material in the Secondary / VA Coil when aligned.

[0089] "Ambient Temperature": The ground-level temperature of the air measured at the subsystem under consideration and not in direct sunlight.

[0090] “Vehicle ground clearance”: the vertical distance between the ground and the lowest part of the vehicle's floor.

[0091] “Vehicle Magnetic Ground Clearance”: The vertical distance between the lower plane of the bottom of the litz wire or magnetic material in a secondary coil or VA coil mounted on a vehicle and the ground.

[0092] "Secondary Coil Surface Distance" or "VA Coil Magnetic Surface Distance" is the distance between the plane closest to the surface of the magnetic or conductive component when mounted and the lower outer surface of the secondary coil or VA coil. Such distance may include any protective coverings and additional items that may be packaged in the secondary coil or VA coil housing.

[0093] The secondary coil may be referred to as a VA coil, a vehicle coil, or a receiver coil. Similarly, the primary coil may be referred to as a GA coil or a transmission coil.

[0094] “Exposed conductive parts”: conductive parts of electrical equipment (e.g., electric vehicles) that can be touched and are not normally energized, but may become energized when a fault occurs.

[0095] “Hazardous live parts”: Live parts that can produce harmful electric shock under certain conditions.

[0096] “Live Parts”: Any conductor or conducting part intended to be energized in normal use.

[0097] “Direct contact”: contact between a person and live parts. See IEC 61140.

[0098] "Indirect contact": contact between a person and an exposed, conductive and live part that has become live through insulation failure. See IEC 61140.

[0099] “Alignment”: The process of finding the relative position of a secondary device with respect to a primary device and / or the relative position of a primary device with respect to a secondary device for effective power transmission. In the present disclosure, alignment may refer to alignment in a wireless power transmission system, but may not be limited thereto.

[0100] "Pairing": The process of associating a vehicle (EV) with a single dedicated power supply device (primary device) arranged so that power transfer can occur. Pairing can include the process of associating an EVPC or VA controller with a SPC or GA controller of a charge point.

[0101] The correlation or associating process may include the process of establishing a relationship between two peer communicating entities.

[0102] “Command and Control Communications”: Communications used to exchange information between the EVSE and the EV required to initiate, control and terminate the wireless power transfer process.

[0103] “High-Level Communications (HLC)”: Digital communications that can handle all information not covered by command and control communications. The data link for HLC can use power line communications (PLC), but is not limited to this.

[0104] "Low Power Excitation (LPE)": A technique that activates a Supply Device (or Primary Device) for fine positioning and pairing so that the EV can detect the Supply Device, and vice versa.

[0105] "Service Set Identifier (SSID)": A unique identifier, comprising 32 characters, appended to the header of packets transmitted on a wireless LAN. The SSID identifies the Basic Service Set (BSS) to which the wireless device is attempting to connect. The SSID distinguishes between multiple wireless LANs. Therefore, all access points (APs) and all terminal / station devices that want to use a particular wireless LAN can use the same SSID. Devices that do not use a unique SSID cannot join the BSS. Because the SSID is shown as plain text, the SSID may not provide any security features to the network.

[0106] "Extended Service Set Identifier (ESSID)": The name of the network you want to connect to. ESSID is similar to SSID, but more extended.

[0107] "Basic Service Set Identifier (BSSID)": The BSSID, which includes 48 bits, is used to distinguish a specific BSS. With an infrastructure BSS network, the BSSID can be configured for medium access control (MAC) of an AP device. For an independent BSS or an Ad-hoc network, the BSSID can be generated using any value.

[0108] The charging station may include at least one GA and at least one GA controller configured to manage the at least one GA. The GA may include at least one wireless communication device. The charging station may refer to a place or location including at least one GA provided in a home, office, public place, road, parking area, etc.

[0109] In this specification, “association” may be used as a term representing a process for establishing wireless communication between an electric vehicle communication controller (EVCC) and a supply equipment communication controller (SECC) controlling a charging infrastructure.

[0110] The electric vehicle charging system may include a conductive charging system using a cable or a contactless wireless power transmission system, but is not limited thereto. The electric vehicle charging system may be defined as a system for charging a battery installed in an electric vehicle using power obtained from a commercial power grid or stored in an energy storage device, and may have various forms depending on the type of electric vehicle.

[0111] The SAE TIR J2954 standard, one of the most representative industry standards for wireless charging, establishes industry standard specification guidelines that define acceptable standards for interoperability, electromagnetic compatibility, minimum performance, safety and testing for wireless charging of light electric vehicles and plug-in electric vehicles.

[0112] As an example of a wireless charging system, a wireless charging system (WCS) according to the J2954 standard may include a grid interface, a high frequency power inverter, a power transfer coil, a filter, a rectifier, an optional regulator, and a communication circuit between the vehicle energy charging / storage system and the grid-connected power inverter. The grid interface may be similar to a conventional EVSE connection for single-phase or three-phase AC power.

[0113] Now, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same components may be represented by the same reference numerals to facilitate overall understanding of the present disclosure, and for the sake of simplicity, repeated description thereof will be omitted.

[0114] Figure 1 is a schematic diagram of a wireless power transmission system to which an exemplary embodiment of the present disclosure can be applied.

[0115] like Figure 1 As shown, wireless power transmission may be performed by at least one of an electric vehicle (EV) 10 and a charging station 20 , and may be used to transmit power to the EV 10 without any conductive wires.

[0116] The EV 10 according to the exemplary embodiment of the present disclosure may include a hybrid electric vehicle (HEV) having an electric motor and an internal combustion engine, and may include not only a car but also a motorcycle, a cart, a scooter, and an electric bicycle.

[0117] The EV 10 may be generally defined as a vehicle that supplies power obtained from a rechargeable energy storage, such as a battery 12 , to an electric motor in a powertrain of the EV 10 .

[0118] The EV 10 may include a power receiving board 11 having a receiving coil adapted to receive power for charging the battery 12 by wireless power transmission, and may include a socket or inlet adapted to receive power for charging the battery 12 by conductive charging. Specifically, the EV 10 configured for conductive charging of the battery 12 may be referred to as a plug-in electric vehicle (PEV).

[0119] The charging station 20 may be connected to a power grid 30 or a power mains, and may provide AC power received from the power grid 30 or the power mains to a power transmission board 21 having a transmission coil through a power link.

[0120] The charging station 20 may communicate with the grid 300 or an infrastructure management system or infrastructure server managing the grid, and may be configured to perform wireless communication with the EV 10. The wireless communication may be performed through Bluetooth, Zigbee, cellular, wireless local area network (WLAN), or the like.

[0121] The charging station 20 may be located in various locations including, but not limited to, a parking area of ​​a home of an owner of the EV 10 , a parking lot for charging EVs at a gas station, a parking lot at a shopping mall or a workplace, and the like.

[0122] Wireless power transmission to the battery 12 of the EV 10 may be performed as follows. First, the power receiving board 11 of the EV 10 is arranged in the energy field above the power transmission board 21. Then, the receiving coil in the power receiving board 11 and the transmitting coil in the power transmission board 21 may be coupled to each other and interact with each other. Due to the coupling or interaction, an electromotive force may be induced in the power receiving board 11, and the battery 12 may be charged by the induced electromotive force.

[0123] The charging station 20 and the power transmission board 21 as a whole or in part may be referred to as a power supply circuit (SPC) or a ground assembly (GA), the meaning and function of which are defined above.

[0124] Also, the power receiving board 11 and all or some of the other internal components of the EV 10 may be collectively referred to as an EV power circuit (EVPC) or a vehicle assembly (VA), the meaning and function of which are defined above.

[0125] Here, each of the power transmission board 21 and the power reception board 11 may be configured as a non-polar board or a polar board.

[0126] A non-polar plate may have one pole in the center of the plate and an opposite pole around its periphery. In this case, magnetic flux may be formed to leave the pole in the center of the plate and return to the pole at the periphery from the outside of the plate.

[0127] The polar plate may have two poles symmetrically arranged at opposite positions on the plate. In this case, a magnetic flux may be formed depending on the orientation of the plate.

[0128] In this specification, the power transmission pad 21 and the power reception pad 11 may be collectively referred to as a wireless charging pad.

[0129] In an exemplary embodiment of the present disclosure, the Y axis of the Cartesian coordinate system may be set to point to the front or rear of the vehicle, the X axis may be set to point to the right or left of the vehicle, and the Z axis may be set to point to the upward or downward direction. The magnetic core of the coil of the power transmission board 21 or the power receiving board 11 may be defined as x=0 and y=0, and the ground surface may be defined as z=0.

[0130] In another exemplary embodiment of the present disclosure, the X-axis may be set to point to the front or rear of the vehicle, and the Y-axis may be set to point to the right or left of the vehicle.

[0131] Figure 2 is a circuit diagram of an equivalent circuit of an electric vehicle wireless charging circuit according to an exemplary embodiment of the present disclosure.

[0132] Figure 2 The left part of the circuit shown in FIG. 1 can be interpreted as a representation of all or part of the power supply Vsrc supplied from the power grid and the charging station 20 including the power transmission board 21, and Figure 2 The right side portion of the circuit shown in can be interpreted as a representation of all or part of an electric vehicle including a power receiving board and a battery.

[0133] Figure 2 The left side portion of the circuit shown in FIG. 1 can provide the output power Psrc corresponding to the power supply Vsrc supplied from the power grid to the primary side power converter. The primary side power converter can perform frequency conversion and AC-DC or DC-AC conversion of the power Psrc to output the converted output power P1 to the transmission coil L1, so that the transmission coil L1 can generate an electromagnetic field at a desired operating frequency.

[0134] The primary side power converter may include an AC-DC converter configured to convert power Psrc, which is AC power supplied from a power grid, into DC power, and a low frequency (LF) converter configured to convert DC power into AC power having an operating frequency suitable for wireless charging. For example, the operating frequency for wireless charging may be determined to be within a frequency range of 80 kHz to 90 kHz, but is not limited thereto.

[0135] The power P1 output by the primary side power converter may be supplied to a circuit including a transmission coil L1, a first capacitor C1, and a first resistor R1. Specifically, the capacitance of the first capacitor C1 may be determined to be a value that establishes an operating frequency suitable for wireless charging together with the transmission coil L1. The first resistor R1 may represent power loss in the transmission coil L1 and the first capacitor C1.

[0136] In addition, the transmission coil L1 can be electromagnetically coupled with the receiving coil L2 through the coupling coefficient m, so that the power P2 is transmitted to the receiving coil L2 or the power P2 is induced in the receiving coil L2. Therefore, the meaning of power transmission in the present disclosure can be used interchangeably with the meaning of power induction.

[0137] The power P2 induced in the receiving coil L2 or transmitted to the receiving coil L2 can be provided to the secondary side power converter. Specifically, the capacitance of the second capacitor C2 can be determined to be a value that establishes an operating frequency suitable for wireless charging together with the receiving coil L2. The second resistor R2 can represent the power loss in the receiving coil L2 and the second capacitor C2.

[0138] The secondary-side power converter may include an AC-DC converter configured to convert the supply power P2 of the operating frequency into DC power having a voltage level suitable for a battery VHV of the EV.

[0139] The electric power PHV converted from the electric power P2 supplied to the secondary-side electric power converter may be used to charge a battery VHV mounted inside the EV.

[0140] Figure 2 The right side portion of the circuit shown in may also include a switch for selectively connecting or disconnecting the receiving coil L2 from the battery VHV.

[0141] The resonant frequencies of the transmission coil L1 and the reception coil L2 may be similar or identical to each other, and the reception coil L2 may be located in the electromagnetic field generated by the transmission coil L1 .

[0142] It should be noted that Figure 2 The circuit is a schematic diagram of a WPT in an EV WPT system used in an exemplary embodiment of the present disclosure, and the present disclosure is not limited to Figure 2 The circuit shown.

[0143] On the other hand, since power loss increases with the distance between the transmission coil L1 and the reception coil L2 , appropriately setting the relative positions of the transmission coil L1 and the reception coil L2 may be an important factor.

[0144] The transmission coil L1 may be included in Figure 1 The transmission board 21 shown in FIG. 1 and the receiving coil L2 may be included in Figure 1 In the receiving board 11 shown in . In addition, the transmission coil can be referred to as a primary coil or a ground assembly (GA) coil, and the receiving coil can be referred to as a secondary coil or a vehicle assembly (VA) coil. Therefore, the positional alignment between the transmission board and the receiving board or the positional alignment between the EV and the transmission board can also be an important factor.

[0145] Figure 1 The positional alignment between the transmission plate 21 shown in and the receiving plate 11 in the electric vehicle 10 can correspond to the above-mentioned term "alignment" and can therefore be defined as the positional alignment between SPC / GA and EVPC / VA, and is not limited to the positional alignment between the transmission plate 21 and the receiving plate 11.

[0146] The transmission plate 21 may be positioned below the ground surface, may be positioned above the ground surface, or may be positioned below the ground surface with its top surface exposed above the ground surface. Figure 2 and Figure 3 As shown, the x-axis may indicate the front-rear direction of the vehicle, the y-axis may indicate the left-right direction of the vehicle, and the z-axis may indicate the up-down direction of the vehicle.

[0147] In addition, the receiving plate 11 of the EV can be defined by different categories according to its height measured from the ground surface (defined in the z direction). For example, a receiving plate 11 having a height of about 100 to 150 millimeters (mm) from the ground surface can be classified as level 1. A receiving plate 11 having a height of about 140 to 210 mm can be classified as level 2. A receiving plate 11 having a height of about 170 to 250 mm can be classified as level 3. The receiving plate can support only some of levels 1 to 3. For example, only level 1 can be supported by the receiving plate 11, or level 1 and level 2 can be supported by the receiving plate 11.

[0148] The height of the receiving plate measured from the ground surface may correspond to the term "vehicle magnetic ground clearance" as defined previously.

[0149] Meanwhile, the vertical position (i.e., the position in the z direction) of the power transmission board 21 may be determined to be arranged between the maximum level and the minimum level supported by the power receiving board 11. For example, in the case where the receiving board supports only level 1 and level 2, the vertical position of the power transmission board 21 may be within a range between about 100 mm and 210 mm relative to the power receiving board 11.

[0150] In addition, the gap between the center of the power transmission board 21 and the center of the power receiving board 11 can be determined to be arranged within the limits of the horizontal direction and the vertical direction (defined in the x direction and the y direction). For example, the gap (for example, Δy) can be determined to be within ±75 mm in the lateral direction (defined in the y direction) and within ±100 mm in the longitudinal direction (defined in the x direction).

[0151] The relative positions of the power transmission board 21 and the power reception board 11 may be changed according to experimental results, and it should be noted that the above-mentioned numerical values ​​are provided as examples.

[0152] Although the alignment between the boards has been described on the assumption that each of the transmission board 21 and the reception board 11 includes a coil, the alignment between the boards may be more specifically defined by alignment between the transmission coil (or GA coil) and the reception coil (or VA coil) respectively included in the transmission board 21 and the reception board 11.

[0153] Figure 3 An equivalent circuit of a single-phase to single-phase wireless power transfer (WPT) system according to an exemplary embodiment of the present disclosure is shown.

[0154] The magnetic / inductive coupling or resonant structure formed between the primary coil and the secondary coil according to various embodiments of the present disclosure may be formed by Figure 3 The transformer shown in is equivalently represented.

[0155] refer to Figure 3 , a single-phase rectifier 210 and a sinusoidal pulse width modulation (SPWM) inverter 220 for applying alternating current to the primary coil may be arranged on one side of the primary coil.

[0156] In addition, a rectifier 110 and a charger 120 for transmitting power from the secondary coil to a load or a battery may be disposed on one side of the secondary coil.

[0157] A wireless power transmission system according to an exemplary embodiment of the present disclosure may include a power transmission circuit. Figure 3 The power transmission circuit shown in FIG. 2 may include a structure consisting of a single-phase rectifier 210 and an SPWM inverter 220 on the primary coil side as a technical feature.

[0158] Figure 3 The illustrated power transmission circuit according to the exemplary embodiment of the present disclosure may adopt a proportional integral (PI) control scheme based on measurement of the single-phase rectifier 210 as a technical feature to control the single-phase rectifier 210 and the SPWM inverter 220 to apply AC power to the primary coil.

[0159] The SPWM inverter 220 may receive the output of the single-phase rectifier 210 and generate alternating current to supply the alternating current as an output to the primary coil.

[0160] Meanwhile, the alternating current rectified by the rectifier 110 may be supplied to the battery by the charger 120 to recharge the battery.

[0161] Figure 4 2 are conceptual cross-sectional views and front views of a conventional power transmission plate which may be a comparative example of the present disclosure.

[0162] Figure 4A transmission coil 21D is shown, which may be included in a device (eg, Figure 3 In the transmission plate 21 in the device shown in ). Figure 4 The transmission board 21 shown in FIG. 1 can support the single-phase operation mode. If the receiving board 11 includes a Figure 4 If the receiving coil (not shown) is shaped like the transmitting coil, the receiving board 11 can perform wireless power reception in the single-phase operation mode. The configuration of the coil and hardware of the receiving board 11 required for the single-phase operation mode can be modified by those skilled in the art. Figure 4 It can be easily implemented by the transmission plate, and its detailed description is omitted for simplicity.

[0163] refer to Figure 4 The power transmission board 21 may include a housing 21A forming an outer structure of the power transmission board 21, an aluminum shield 21B having a planar plate shape and installed inside the housing 21A, a ferrite plate 21C installed on or over the aluminum shield 21B, and a transmission coil 21D installed on or over the ferrite plate 21C. Here, "on or over" refers to an upward direction relative to the ground on which the power transmission board 21 is installed.

[0164] Here, ferrite used for the ferrite plate 21C is a magnetic material containing iron oxide, and can affect wireless power transmission by reducing magnetic resistance and facilitating the flow of magnetic flux.

[0165] In the following, we will start with Figure 4 The configuration of the device according to the exemplary embodiment of the present disclosure is described from the perspective of different aspects of the conventional power transmission board shown in FIG.

[0166] Figure 5 is a perspective view illustrating a power transmission board and a power reception board including a magnetic core structure according to an exemplary embodiment of the present disclosure.

[0167] Figure 6 2 are front and side views showing a power transmission board and a power reception board including a magnetic core structure according to an exemplary embodiment of the present disclosure.

[0168] Figure 7 is a conceptual plan view illustrating a power transmission board and a power reception board including a magnetic core structure according to an exemplary embodiment of the present disclosure.

[0169] refer to Figures 5 to 7 , the power transmission board or device 21 according to an exemplary embodiment of the present disclosure may include a primary coil 400 , magnetic core structures 310 , 320 , and 320A, and a housing.

[0170] The housing may support the primary coil 400 and the magnetic core structures denoted by reference numerals 310 , 320 , and 320A.

[0171] The power receiving board or device 11 according to an exemplary embodiment of the present disclosure may include a secondary coil 500 .

[0172] A magnetic core structure 310, 320 or 320A provided with a primary coil 400 for wireless power transmission (WPT) according to an exemplary embodiment of the present disclosure may include: a first structure 320, formed on a support structure 310 to protrude within a first space 330 including the center of the primary coil 400 and extend in a first axis direction; a second structure 320A, spaced apart from the first structure in the second axis direction, protruding in the same direction as the first structure and extending in the first axis direction; and a support structure 310, supporting the first structure 320 and the second structure 320A, and having the same magnetic properties as the first structure 320 and the second structure 320A.

[0173] The support structure 310, the first structure 320, and the second structure 320A may be formed of a magnetic material. Examples of the magnetic material may include the above-mentioned ferrite, but the present disclosure is not limited to a specific material.

[0174] The first and second structures 320 and 320A may be arranged such that a spacing distance therebetween may be maximized within the first space 330. The first space 330 including the center of the primary coil 400 may represent an effective usable area that can be surrounded by the primary coil 400 without being invaded by the primary coil 400.

[0175] The first structure 320 and the second structure 320A may be symmetrically arranged with respect to the center of the primary coil 400 .

[0176] The first structures 320 and the second structures 320A may protrude in the third axis direction more than the first reference value.

[0177] The first reference value may be a height of the first structure 320 or the second structure 320A capable of achieving a target ratio of the coupling coefficient k, and may be selected from an allowable range of power transmission between the primary coil 400 and the secondary coil 500 at a frequency at which wireless power transmission is performed.

[0178] Examples of the allowable range Z-gap of power transmission may include 140 millimeters (mm), 175 mm, and 210 mm, etc. The allowable range Z-gap of power transmission may vary depending on the ground clearance range of the vehicle component (VA). For example, assuming that the ground clearance range of the vehicle component may have a value of 100 mm to 150 mm for level Z1, a value of 150 mm to 200 mm for level Z2, and a value of 200 mm to 250 mm for level Z3, the allowable range Z-gap of power transmission may be set corresponding to each level.

[0179] For example, a target ratio of the coupling coefficient k may be set to 70% at a frequency of 85 kilohertz (kHz).

[0180] For example, the first reference value may be 50 mm at a frequency of 85 kHz.

[0181] The first structures 320 and the second structures 320A may have a width greater than or equal to a second reference value in the second axis direction.

[0182] The second reference value may be the width of the first structure 320 and the second structure 320A in the Y-axis direction that can achieve a target ratio of the coupling coefficient k, and may be selected from an allowable range of the spacing distance between the center of the primary coil 400 and the center of the secondary coil 500 on the XY plane. The second reference value may also be interpreted as a reference value of the thickness of the wall-like structure.

[0183] For example, for the offset in the X-axis direction, the allowable range of the spacing distance may be 75 mm, and for the offset in the Y-axis direction, the allowable range of the spacing distance may be 100 mm.

[0184] For example, the target ratio of the coupling coefficient k may be set to 70% at a frequency of 85 kHz.

[0185] For example, the second reference value may be 25 mm at a frequency of 85 kHz.

[0186] Alternatively, the second reference value may be 50 mm at a frequency of 85 kHz.

[0187] The primary coil 400 may be arranged to surround the first structure 320 and the second structure 320A, and have a predetermined height in the third axis direction. In this case, the predetermined height may be a uniform height.

[0188] According to wireless power transmission, energy is transmitted using RF signals, lasers, sound waves, etc. instead of transmitting electrical energy through conductive wires.

[0189] Inductive wireless power transfer is a wireless power transfer technology for transferring energy through magnetic induction occurring between coils, and is suitable for transferring high power to charge a large-capacity battery in an electric vehicle, for example.

[0190] The inductive wireless power transmission system includes a transmission coil (ie, primary coil) and a reception coil (ie, secondary coil), and a matching circuit may be incorporated to make the transmission coil and the reception coil resonate at the same frequency and increase power transmission efficiency.

[0191] Although the inductive wireless power transmission system has a very simple configuration, the system has limited freedom in the power transmission distance between coils and the alignment between coils.

[0192] The present disclosure provides a magnetic structure that can reduce performance degradation caused by a deviation in a power transmission distance between a transmitting coil and a receiving coil and an alignment between coils in an inductive wireless power transmission system for an electric vehicle.

[0193] According to the inductive wireless power transmission system for electric vehicles of an exemplary embodiment of the present disclosure, the magnetic structure can compensate for the deviation of the power transmission distance between the primary coil 400 and the secondary coil 500 and the alignment between the coils, so that power can be effectively transmitted from the primary coil 400 to the secondary coil 500.

[0194] The magnetic structure according to the exemplary embodiment of the present disclosure may increase the degree of freedom in the power transmission distance between the primary coil 400 and the secondary coil 500 and the alignment between the coils.

[0195] In the magnetic structure according to the exemplary embodiment of the present disclosure, a magnetic core having two wall structures 320 and 320A is arranged in a space surrounded by the primary coil 400 to adjust the mutual inductance and coupling coefficient of the coils so that power transmission efficiency can be improved even in a misaligned state.

[0196] According to an exemplary embodiment of the present disclosure, the magnetic core having the wall-like structures 320 and 320A is arranged at the maximum available misalignment position to increase the coupling coefficient at the misalignment position without reducing the coupling coefficient at the alignment position, thereby improving the power transmission efficiency at each misalignment position within the maximum available misalignment range.

[0197] Exemplary embodiments of the present disclosure provide a wireless power transmission (WPT) device 21 having an optimized arrangement of a novel magnetic core structure and exhibiting enhanced power transmission efficiency, and a wireless power transmission method using the wireless power transmission device.

[0198] According to another embodiment of the present disclosure, the center of the primary coil 400 and the center of the secondary coil 500 do not necessarily have to coincide horizontally, having the same XY coordinates. Even if the XY coordinates of the center of the primary coil and the center of the secondary coil do not coincide with each other, power can be wirelessly transmitted from the primary coil 400 to the secondary coil 500. However, despite this, it may be suggested to align the center of the secondary coil with the center of the primary coil, because severe misalignment of the centers can significantly reduce the efficiency of wireless power transmission.

[0199] In addition, a difference in XY coordinates between the center of the primary coil and the center of the secondary coil may be less than a predetermined reference value to ensure desired efficiency of wireless power transmission.

[0200] For example, SAE J2954, a ground vehicle standard directed to wireless power transmission and alignment methods for light plug-in / electric vehicles, specifies the maximum tolerance for alignment offset in the XY plane between the center of the primary coil 400 and the center of the secondary coil 500 as ±75 mm in the minor axis (X-axis) direction and ±100 mm in the major axis (Y-axis) direction.

[0201] Generally, when the center of the primary coil 400 and the center of the secondary coil 500 are spaced apart, ie, the coils are misaligned, power transmission efficiency may be lower than when the center of the primary coil 400 and the center of the secondary coil 500 are aligned.

[0202] Generally, the magnetic flux or magnetic field at the boundary of the first space 330 may be much smaller than the magnetic flux or magnetic field at the center, the first space being an effective internal space surrounded by the primary coil 400 and including the center of the primary coil 400, and thus the coupling coefficient and the power transmission efficiency may decrease as the misalignment distance between the primary coil and the secondary coil increases. Generally, when the center of the primary coil 400 and the center of the secondary coil 500 are offset by the maximum tolerance interval of the alignment in the long axis (Y axis) direction, the power transmission efficiency may be significantly reduced.

[0203] The magnetic core structure according to the exemplary embodiment of the present disclosure may overcome the problem of a conventional magnetic structure in which the magnetic flux is rapidly reduced near the boundary of the first space 330 .

[0204] According to the exemplary embodiment of the present disclosure, even at the boundaries of both ends of the first space 330 , magnetic flux facilitating power transmission may be maintained, and the coupling coefficient between coils and power transmission efficiency may be improved.

[0205] The magnetic core structure according to the exemplary embodiment of the present disclosure can exhibit robust magnetic characteristics for misalignment offset between the primary coil and the secondary coil, and can improve power transmission efficiency. The characteristics of robust power transmission efficiency for misalignment offset between the coils can be derived from the feature that the coupling coefficient k can be greater than the reference value near the boundaries at both ends in the long axis (Y axis) direction of the first space 330.

[0206] In an exemplary embodiment of the present disclosure, when the maximum tolerance of alignment deviation in the major axis direction is greater than the tolerance of alignment deviation in the minor axis direction, the primary coil may have a structure wound in a rectangular cross-section whose length in the major axis direction is greater than the length in the minor axis direction.

[0207] The reduction in power transmission efficiency caused by the spacing distance between the centers of the coils can be compensated by adopting a magnetic core structure having a protrusion in the empty space on the magnetic plate arranged between the primary coil and the shielding plate. However, this structure has the following disadvantages: although a high coupling coefficient and a high power transmission efficiency are shown when the primary coil 400 and the secondary coil 500 are aligned at the centers of the coils, when the centers of the coils are misaligned by an amount equal to the maximum tolerance of the alignment offset, the coupling coefficient and the power transmission efficiency are reduced.

[0208] In an exemplary embodiment of the present disclosure, a compensation core structure as a modified example of a conventional magnetic core may be arranged to be surrounded by the primary coil 400. According to the exemplary embodiment, the two wall-shaped magnetic structures 320 and 320A may be arranged at a position where the magnetic flux may affect a reduction in power transmission efficiency, unlike a conventional transformer having a single structure in which a magnetic core occupies most of the internal space of the coil.

[0209] Generally, when a magnetic core is inserted into a coil, the magnetic core is magnetized and magnetic flux around the magnetic core is strengthened, and a coupling coefficient between the coils increases.

[0210] When a magnetic core with a single structure occupies most of the internal space of the coil, the coupling coefficient between the coils increases, but the difference in coupling coefficient between the case where the centers of the coils are aligned with each other and the case where the centers of the primary coil and the secondary coil are spaced apart from each other with a maximum tolerance for alignment deviation becomes larger.

[0211] Exemplary embodiments of the present disclosure provide a magnetic core structure that is robust to a misalignment distance as a modification of a conventional magnetic core to address a reduction in power transmission efficiency caused by a difference in coupling coefficient.

[0212] The wall-shaped core structures 320 and 320A extending in the short axis direction of the rectangular coil according to the exemplary embodiment of the present disclosure can strengthen the magnetic flux around the core to increase the coupling coefficient between the coils when the centers of the primary coil and the secondary coil are significantly spaced apart (e.g., the amount of the maximum tolerance of the alignment offset). The coupling coefficient in the blank space where the core structure is not placed in the central space inside the coil can be uniformly maintained by adjusting the thickness of the core structure. Therefore, the exemplary embodiment of the present disclosure can enhance the uniformity of the coupling coefficient according to the misalignment distance.

[0213] The wall-shaped core structures 320 and 320A according to the exemplary embodiments of the present disclosure may be applied to any annular wireless power transmission coil, and the uniformity of the coupling coefficient may be increased without loss of the coupling coefficient by changing the height and thickness of the core structure according to the structure of the coil.

[0214] refer to Figure 7 , assuming that the primary coil 400 has a substantially rectangular horizontal cross-section. The edges of the primary coil 400 may be rounded.

[0215] According to an exemplary embodiment of the present disclosure, the primary coil 400 and the secondary coil 500 may have a substantially rectangular cross-section in which a length in a major axis direction is greater than a length in a minor axis direction.

[0216] Figure 8 is a perspective view showing the power transmission board 21 and the power reception board 11 including the magnetic core structures 320 and 320A according to another exemplary embodiment of the present disclosure.

[0217] Fig. 9 1 are front and side views showing the power transmission board 21 and the power reception board 11 including the magnetic core structures 320 and 320A according to another exemplary embodiment of the present disclosure.

[0218] refer to Figure 8 and Fig. 9 The primary coil 420 surrounding the first structure 320 and the second structure 320A may generally include a primary coil wire wound by one or more turns, and may generally have the shape of a truncated pyramid, wherein each turn of the primary coil wire may be positioned higher in the direction of the third axis, closer to the center of the primary coil 420.

[0219] For simplicity, omit Figure 8 and Fig. 9 As shown in Figures 5 to 7 The configuration shown in the description of the configuration is repeated.

[0220] Fig.10is a perspective view showing the power transmission board 21 and the power reception board 11 including the magnetic core structures 320 and 320A according to still another exemplary embodiment of the present disclosure.

[0221] Fig.11 1 and 2 are front and side views showing the power transmission board 21 and the power reception board 11 including the magnetic core structures 320 and 320A according to still another exemplary embodiment of the present disclosure.

[0222] refer to Fig.10 and Fig.11 The primary coil 440 surrounding the first structure 320 and the second structure 320A may generally include a primary coil wire wound by one or more turns, and may generally have the shape of an inverted truncated pyramid, wherein each turn of the primary coil wire may be positioned lower in the direction of the third axis, closer to the center of the primary coil 440.

[0223] For simplicity, omit Fig.10 and Fig.11 As shown in Figures 5 to 7 The configuration shown in the description of the configuration is repeated.

[0224] exist Figures 5 to 11 In the exemplary embodiment shown in , the coil 400 and the coil 500 may be implemented by a flat wire. Each coil may be formed of a flat wire wound by one or more turns.

[0225] Alternatively, in Figures 5 to 11 The coil 400 and the coil 500 in the exemplary embodiment shown in FIG. 4 may be implemented by a litz wire. Each coil may be formed by a litz wire wound by one or more turns.

[0226] Compared with conventional copper wire, the advantages of twisted wire are that the current flow does not become unstable as the current increases, the loss is small, so that a stable current flow can be maintained, and the temperature rise of the coil is less. Therefore, twisted wire is an appropriate material for an electric vehicle wireless power transmission system using an operating frequency of 79kHz to 90kHz. Generally, the price of twisted wire is set as a price per meter. There are attempts to use twisted wire in an electric vehicle wireless power transmission system in consideration of these characteristics of the twisted wire.

[0227] However, a wireless power transmission system for light electric vehicles requires a twisted wire with a large current capacity (eg, at least 50 A or more), which is several dozen times more expensive than ordinary twisted wires and causes an increase in the manufacturing cost of electric vehicles.

[0228] Because electric vehicle wireless charging systems transfer large amounts of power wirelessly, strict thermal management is always important. In addition, managing the heat generated by foreign objects such as metal is also important.

[0229] However, due to the structure of the twisted wire in which the inner strand is surrounded by the outer strand, it may be difficult to quickly discharge the generated heat to the outside of the twisted wire. In addition, as the heat generation continues, the current loss in the twisted wire increases. Therefore, it may be difficult to use the twisted wire for a long time. Therefore, the power transmission system using the twisted wire requires a cooling arrangement, which further increases the cost.

[0230] Even if a cooling arrangement is added to the system, the thermal conductivity of the strands may be too low to quickly dissipate the generated heat to the exterior of the strands, and thus the overall cooling efficiency may still be low.

[0231] Furthermore, there may be some opinion that a support structure that maintains the shape of a coil made of litz wires may compromise the safety of the system.

[0232] Although the stranded wire has a higher strength than conventional copper wire and is convenient for maintaining the shape of the wire, the stranded wire is straight, and a coil made of the stranded wire may require a frame to maintain the shape of the stranded wire and the coil. Such a frame is made of a dielectric with a low dielectric constant to reduce electromagnetic influence on the operation of the coil. Dielectrics with a low dielectric constant are generally susceptible to heat and are therefore insufficient for high-power charging of, for example, 22 kilowatts (KW) that generates a large amount of heat. In addition, because the frame is in contact with the stranded wire, the frame may hinder heat exchange, undergo changes in the shape of the frame during repeated heating and cooling processes, or cause a fire.

[0233] Therefore, the present disclosure provides alternative examples in addition to the example using the twisted wire.The wireless power transmission board or the power receiving board according to the embodiment of the present disclosure may be implemented using a flat wire.

[0234] The flat and rectangular conductive line according to the exemplary embodiment of the present disclosure may be a modified example of a commercially available flat wire to suit the purpose of the present disclosure.

[0235] The flat wires available on the market usually have almost right-angled corners. These commercially available flat wires are used to increase the space factor. The wire according to the alternative example of the present disclosure maintains its flat shape with at least partially rounded corners.

[0236] The wire proposed by the present disclosure has the following characteristics: 1) having a flat or planar shape, and 2) having a partially circular and / or partially rectangular side. The wire having such characteristics according to the example of the present disclosure can be a flat wire having a shape optimized to generate an electromagnetic field suitable for wireless power transmission when wound into a coil.

[0237] Flat and rectangular wires are available in a variety of sizes, for example, single or multiple strands (e.g., eight strands), a thickness range of 1.0 millimeters (mm) to 1.9 mm, and a width range of 3 mm to 20 mm. In addition, the rectangular wires can be wound into coils in the form of a continuously transposed conductor (CTC).

[0238] An advantage of coils made from this wire is that the coils can be used in high voltage applications and the insulation to conductor bonding is good enough to select and use one of a variety of insulation materials such as KRAFT, THERMALUPGRADE KRAFT, NOMEX, DENNISON, KAPTON, MICA, and CONDUCTOFOL.

[0239] If the insulation problem is solved in this way, the number of turns can be increased compared to the existing litz wire coil, and the increase in the number of turns can create increased magnetic flux and enhance power transmission efficiency.

[0240] Furthermore, because a coil made of such a wire is essentially a single cylindrical metal structure when viewed from the outside, heat can be quickly transferred from the inside to the outside without any discontinuity.

[0241] In addition, the twisted wire has a structure in which the inner strand is surrounded by the outer strand as described above. Therefore, when an internal short circuit or insulation deformation or deterioration occurs, it is difficult to identify the location of the fault, and partial maintenance of the wire may be impossible and the entire coil must be replaced, which leads to an increase in maintenance costs. However, the coil structure using the flat wire or planar wire proposed in the present disclosure is more durable than the twisted wire, and therefore, faults such as short circuits in the wire are less likely to occur. In addition, even if a fault occurs, the location where the fault occurs can be easily identified. Therefore, the fault can be repaired immediately, and even if the coil itself is replaced, the replacement cost is low. Therefore, the coil structure according to the present disclosure requires much fewer resources for maintenance.

[0242] In addition, the use of a flat wire structure has the advantages of high heat transfer efficiency and high arrangement freedom, which can selectively apply various cooling technologies such as dry self-cooling, dry air cooling, dry sealed self-cooling, inflow self-cooling, inflow air cooling, oil flow water cooling, oil flow air cooling, and refrigerant cooling. Because various cooling technologies can be selectively applied or applied in combination, the embodiments of the present disclosure can have a very advantageous effect in cooling the heat generated during power transmission.

[0243] The flat wire according to the exemplary embodiment of the present disclosure may be implemented using at least one material selected from copper and a copper alloy, but the scope of the present disclosure is not limited thereto and various conductors may also be used for the flat wire.

[0244] At the same time, it may be advantageous to establish an electromagnetic field near the coil to at least partially round the corners of the coil. The curvature to which the corners are rounded may also be determined in consideration of power transmission efficiency, the shape of the coil, and the like.

[0245] In the example, by determining the aspect ratio of the cross-section of the wire and the numerical range of the curvature of the fillet, the coil structure 400 or the coil structure 500 according to the exemplary embodiment of the present disclosure can be realized based on the shape and material of the bus forming the conductor connected to the battery inside the electric vehicle 10.

[0246] Comparing the example using twisted wire to an alternative example, although twisted wire is a technology designed to increase the ratio of surface area (i.e., current path) to cross-sectional area or volume, interference between the twisted wire strands in the central space of the twisted wire bundle (where the twisted wires are densely packed) reduces power transmission efficiency and increases heat generation.

[0247] Because current flows over the surface of a conductor, the ratio of surface area to cross-sectional area can be understood as corresponding to the ratio of current path to total volume.

[0248] By proposing a coil structure using a flat wire, examples of the present disclosure may increase a ratio of a surface area to a cross-sectional area and improve a space factor, thereby increasing power transmission efficiency.

[0249] The rounded corners may aid in the formation of the electromagnetic field, resulting in more favorable electromagnetic properties of the coil.

[0250] Fig.12 is a flowchart conceptually illustrating a wireless power transmission method according to an exemplary embodiment of the present disclosure.

[0251] Fig.12 The wireless power transmission method shown in may correspond to Figures 5 to 11 The embodiment shown in .

[0252] A wireless power transmission method according to an exemplary embodiment of the present disclosure is a method for wirelessly transmitting power from a transmission plate 21 including a primary coil 400 to a receiving plate 11 including a secondary coil 500, including: an operation S700 of setting a magnetic core structure, the magnetic core structure including a first magnetic structure 320, the first magnetic structure being configured to protrude within a first space 330 including a center of the primary coil 400 and to extend in a first axial direction; and a second magnetic structure 320A, the second magnetic structure being spaced apart from the first magnetic structure 320 in a second axial direction and being configured to protrude in the same direction as the first magnetic structure 320 and to extend in the first axial direction; an operation S800 of positioning the center of the secondary coil 500 within a predetermined offset range from the center of the primary coil 400; and an operation S900 of supplying input power to the primary coil 400 and wirelessly transmitting the input power to the secondary coil 500.

[0253] In operation S700 of setting the magnetic core structure, the first magnetic structure 320 and the second magnetic structure 320A may be arranged to protrude in the third axis direction by more than a first reference value.

[0254] The wireless power transmission method according to the exemplary embodiment of the present disclosure may further include an operation S600 of providing the primary coil 400 surrounding the first magnetic structure 320 and the second magnetic structure 320A.

[0255] refer to Figures 5 to 7 In the embodiment of the present invention, in operation S600, the primary coil 400 may be arranged to have a predetermined height in the third axis direction. In this case, the predetermined height may be a uniform height.

[0256] refer to Figure 8 and Fig. 9 In an embodiment, in operation S600, the primary coil 420 may be arranged to generally have a truncated pyramid shape, wherein each turn of the primary coil wire may be positioned higher in the third axis direction as it is closer to the center of the primary coil 420.

[0257] refer to Fig.10 and Fig.11 In an embodiment, the primary coil 440 may be arranged to generally have a shape of an inverted truncated pyramid, wherein each turn of the primary coil wire may be positioned lower in the direction of the third axis, closer to the center of the primary coil 440 .

[0258] Fig.13 is a block diagram showing a general configuration of hardware included in or associated with a wireless power transmission board and / or a wireless power reception board to control a sequence for wireless power transmission.

[0259] For convenience of explanation, hardware controlling a sequence for wireless power transmission may be referred to as a controller 1000 .

[0260] The controller 1000 may be disposed on a side of the electric vehicle 100 , on a side of electric vehicle supply equipment (EVSE), or on a side of the power transmission board 21 .

[0261] The controller 1000 may include at least one processor 1100, a memory 1200 storing at least one instruction for performing the above-mentioned operation by the processor 1100, and a communication interface 1300 connected to a network to perform communication. The controller 1000 for wireless power transmission may also include a storage device 1400 capable of storing at least one instruction for performing the above-mentioned operation or data generated during the execution of the instruction. The controller 1000 for wireless power transmission may also include an input interface 1500 and an output interface 1600 for interacting with a user. The components of the controller 1000 for wireless power transmission may be connected to each other through a system bus 3700 to communicate with each other.

[0262] The controller or computing system 1000 according to an embodiment of the present disclosure may include at least one processor 1100 and a memory 1200 storing program instructions instructing the at least one processor 1100 to perform at least one processing step. At least some operations or processing steps of the method according to an embodiment of the present disclosure may be performed by at least one processor 1100 loading and executing the program instructions from the memory 1200.

[0263] The processor 1100 may include a central processing unit (CPU) or a graphics processing unit (GPU), or may be implemented by another dedicated processor suitable for executing the method of the present disclosure.

[0264] Each of the memory 1200 and the storage device 1400 may include at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 1200 may include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0265] Here, at least one instruction may include at least one of the following: a sequence suitable for identifying at least one of the electric vehicle 10, the electric vehicle supply equipment (EVSE) 20 and the power transmission board 21, a sequence suitable for associating two or more devices among the electric vehicle 10, the electric vehicle supply equipment (EVSE) 20 and the power transmission board 21 through wireless communication, a sequence suitable for performing alignment and / or pairing through positioning of the other device, and a sequence suitable for allowing supply of alternating current for power transmission after alignment and / or pairing.

[0266] Furthermore, the controller 1000 may include a communication interface 1300 that performs communication through a wireless communication network.

[0267] In addition, the controller 1000 may further include a storage device 1400 , an input interface 1500 , and an output interface 1600 .

[0268] The components of the controller 1000 may be connected to each other through the system bus 1700 to communicate with each other.

[0269] The controller 1000 according to an exemplary embodiment of the present disclosure may be any data processing device capable of communicating over a network, such as a desktop computer, a laptop computer, a notebook PC, a smart phone, a tablet PC, a mobile phone, a smart watch, smart glasses, an e-book reader, a portable multimedia player (PMP), a portable game console, a navigation device, a digital camera, a digital multimedia broadcasting (DMB) player, a digital audio recorder, a digital audio player, a digital video recorder, a digital video player, and a personal digital assistant (PDA).

[0270] Computer readable recording media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Program instructions may include not only machine language codes generated by a compiler, but also high-level language codes executable by a computer using an interpreter, etc.

[0271] Some aspects of the disclosure described above in the context of the device can indicate the corresponding description according to the method of the present disclosure, and the block or device can correspond to the operation of the method or the feature of the operation. Similarly, some aspects described in the context of the method can be expressed by the features of the corresponding blocks, items or devices. For example, some or all of the operation of the method can be performed by (or using) hardware devices such as microprocessors, programmable computers or electronic circuits. In some exemplary embodiments, one or more of the most important operations of the method can be performed by such a device.

[0272] In some exemplary embodiments, a programmable logic device such as a field programmable gate array can be used to perform some or all of the functions of the methods described herein. In some exemplary embodiments, the field programmable gate array can be operated using a microprocessor to perform one of the methods described herein. Typically, the method is preferably performed by a hardware device.

[0273] The description of the present disclosure may be merely exemplary in nature, and therefore, changes that do not deviate from the essence of the present disclosure may be intended to fall within the scope of the present disclosure. Such changes may not be considered as departing from the spirit and scope of the present disclosure. Therefore, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope defined by the appended claims.

[0274] Industrial Applicability

[0275] Exemplary embodiments of the present disclosure provide a magnetic structure that enables efficient power transmission in an inductive wireless power transmission system for an electric vehicle by reducing performance degradation that may be caused by a deviation in a power transmission distance between a primary coil and a secondary coil and alignment between the coils.

Claims

1. A magnetic core structure provided with a primary coil (primary coil) for wireless power transmission (WPT, wireless power transmission), the magnetic core structure comprising: a first structure configured to protrude in a first space including a center of the primary coil and to extend in a first axial direction; a second structure spaced apart from the first structure in a second axis direction and configured to protrude in the same direction as the first structure and to extend in the first axis direction; as well as A support structure is configured to support the first structure and the second structure and has the same magnetic properties as the first structure and the second structure.

2. The magnetic core structure according to claim 1, wherein: The first structure and the second structure are arranged such that a spacing distance between the first structure and the second structure is maximized within the first space.

3. The magnetic core structure according to claim 1, wherein: The first structure and the second structure are arranged symmetrically with respect to a center of the primary coil.

4. The magnetic core structure according to claim 1, wherein: The first structure and the second structure are configured to protrude in a third axis direction by more than a first reference value.

5. The magnetic core structure according to claim 4, wherein: The first reference value is 50 mm.

6. The magnetic core structure according to claim 1, wherein: The first structures and the second structures have a width in the second axis direction that is greater than or equal to a second reference value.

7. The magnetic core structure according to claim 6, wherein: The second reference value is 25 mm.

8. The magnetic core structure according to claim 1, wherein: The primary coil is arranged to surround the first structure and the second structure, and includes a primary coil wire wound by one or more turns having a predetermined height in a third axis direction.

9. The magnetic core structure according to claim 1, wherein: The primary coil is arranged to surround the first structure and the second structure, and includes a primary coil wire wound by one or more turns, wherein the turns of the primary coil wire are positioned higher in a third axis direction as they are closer to a center of the primary coil.

10. The magnetic core structure according to claim 1, wherein: The primary coil is arranged to surround the first structure and the second structure, and includes a primary coil wire wound by one or more turns, wherein the turns of the primary coil wire are positioned lower in a third axis direction as they are closer to a center of the primary coil.

11. A wireless power transmission device, configured to wirelessly transmit power to a receiving board including a secondary coil (secondary coil), the wireless power transmission device comprising: Primary coil (primary coil); a first magnetic structure configured to protrude in a first space including a center of the primary coil and to extend in a first axial direction; a second magnetic structure spaced apart from the first magnetic structure in a second axis direction and configured to protrude in the same direction as the first magnetic structure and extend in the first axis direction; a supporting magnetic structure configured to support the first magnetic structure and the second magnetic structure and having the same magnetic properties as the first magnetic structure and the second magnetic structure; as well as The housing is configured to support the primary coil, the first magnetic structure, the second magnetic structure and the supporting magnetic structure.

12. The wireless power transmission device according to claim 11, wherein: The first magnetic structure and the second magnetic structure are arranged such that a spacing distance between the first magnetic structure and the second magnetic structure is maximized within the first space.

13. The wireless power transmission device according to claim 11, wherein: The first magnetic structure and the second magnetic structure are arranged symmetrically with respect to a center of the primary coil.

14. The wireless power transmission device according to claim 11, wherein: The first magnetic structure and the second magnetic structure are configured to protrude in a third axis direction by more than a first reference value.

15. The wireless power transmission device according to claim 11, wherein: The first magnetic structure and the second magnetic structure have a width in the second-axis direction that is greater than or equal to a second reference value.

16. A method of wirelessly transmitting power from a transmitting pad including a primary coil (primary coil) to a receiving pad including a secondary coil (secondary coil), comprising: Providing a magnetic core structure, the magnetic core structure comprising: a first magnetic structure configured to protrude in a first space including a center of the primary coil and to extend in a first axial direction; and a second magnetic structure spaced apart from the first magnetic structure in a second axial direction and configured to protrude in the same direction as the first magnetic structure and to extend in the first axial direction; positioning the center of the secondary coil within a predetermined offset range from the center of the primary coil; and Input power is supplied to the primary coil, and the input power is wirelessly transmitted to the secondary coil.

17. The method according to claim 16, wherein: The first magnetic structure and the second magnetic structure are configured to protrude in a third axis direction by more than a first reference value.

18. The method according to claim 16, further comprising: The primary coil is disposed around the first magnetic structure and the second magnetic structure, and includes a primary coil wire wound by one or more turns having a predetermined height in a third axis direction.

19. The method according to claim 16, further comprising: The primary coil is disposed around the first magnetic structure and the second magnetic structure and includes a primary coil wire wound by one or more turns, the turns of the primary coil wire being positioned higher in a third axis direction as they are closer to a center of the primary coil.

20. The method of claim 16, further comprising: The primary coil is disposed around the first magnetic structure and the second magnetic structure and includes a primary coil wire wound by one or more turns, the turns of the primary coil wire being positioned lower in a third axis direction as they are closer to a center of the primary coil.

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