WIRELESS CHARGING SYSTEM FOR ELECTRIC VEHICLES

Abstract

A wireless charging system for an electric vehicle (5), comprising: a transmission device (100) having a transmission pad (10) installed separately from the vehicle (5) and configured to generate an electromagnetic field by receiving energy, and a reception device (200) having a reception pad (20) installed inside the vehicle (5) and configured to be arranged so as to face the transmission pad (10), and configured to induce a voltage by means of the electromagnetic field generated by the transmission pad (10) and to charge a battery of the vehicle (5), wherein the transmission pad (10) is configured to transmit a maximum output power even if the transmission pad (10) is configured to be asymmetrical to the reception pad (20) in a width direction of the vehicle.

Description

Technical field

[0001] The present invention relates to a wireless charging system for an electric vehicle. background

[0002] In general, a wireless charging system for an electric vehicle consists of a transmitting device which is installed outside a vehicle and has a transmitting pad, and a receiving device which has a receiving pad and is installed inside the vehicle.

[0003] The transmitter converts the power supplied by a system into a high-frequency alternating current (AC) signal via a switching device and delivers the high-frequency AC signal to the transmitter pad. A time-varying magnetic field generated by the transmitter pad induces a voltage at the receiver pad. A power conversion circuit attached to the receiver converts the voltage received by the receiver pad into a DC voltage for charging a high-voltage battery. In this case, the magnitude and efficiency of the wirelessly transmitted power vary depending on the alignment state (a vertical direction Z, a longitudinal direction X, and a transverse direction Y) between the transmitter pad and the receiver pad.

[0004] In a wireless charging system for an electric vehicle in the related art, the receiving pad is mainly mounted on a lower portion of the vehicle. In this case, the alignment state between the transmitting pad and the receiving pad may vary depending on a parking condition / loading condition, causing fluctuations in wireless charging performance, such as output power, efficiency, etc.

[0005] Even if alignment deviations are within allowable ranges for vertical and longitudinal / lateral pitch, the volume / weight / cost / complexity of a resonant pad and a compensation circuit for energy transfer increase.

[0006] Therefore, a system is proposed in which a vertical distance between the transmission pad and the reception pad is adjusted and kept constant by a method of connecting an actuator to the transmission pad, or a system is proposed in which the vertical distance between the transmission pad and the reception pad is kept constant by a method of connecting the actuator to the reception pad and lifting the actuator connected to the reception pad, however, when a longitudinal / lateral alignment error is taken into account, position control for a maximum of 3 axes is required, so there is a problem that the complexity of the actuator is greatly increased. Explanation of the invention

[0007] The present disclosure or invention (hereinafter referred to as disclosure) relates to a wireless charging system for an electric vehicle and, more particularly, to a wireless charging system for an electric vehicle having a double pole resonant pad with an asymmetric structure.

[0008] Accordingly, an embodiment of the present disclosure may provide a wireless charging system for an electric vehicle in which a positional error may occur in vehicle alignment for wireless charging, and in which a transmitting means may be configured by a double-pole pad, and a size of a transverse core may be configured asymmetrically to a receiving pad by considering an allowable transverse deviation between a transmitting pad and the receiving pad.

[0009] An exemplary embodiment of the present disclosure provides a wireless charging system for an electric vehicle, which may include: a transmitting device that has a transmitting pad installed separately from the vehicle and generates an electromagnetic field by receiving power, and a receiving device that has a receiving pad installed inside the vehicle and arranged to face the transmitting pad, and that induces a voltage by means of the electromagnetic field generated by the transmitting pad and charges a battery, wherein the transmitting pad may be provided to transmit a maximum output power even though the transmitting pad is formed to be asymmetrical with the receiving pad in a width direction of the vehicle.

[0010] The receiving device may comprise a power conversion circuit for converting a power received by the receiving pad into a DC voltage.

[0011] The wireless charging system may further include an actuator installed in the vehicle that adjusts / adjusts a cavity (vertical distance, e.g., a clearance / air gap) between the transmitting pad and the receiving pad.

[0012] The cavity between the transmitting pad and the receiving pad can be set as an intermediate distance of 100 mm or less.

[0013] The wireless charging system may further include a parking block installed separately from the vehicle and adjusting a longitudinal orientation (x-axis orientation) of the vehicle.

[0014] The transmission pad may have a double-pole resonance pad structure, and the double-pole resonance pad structure may include a first magnet formed to protrude in a height direction of the vehicle and wound with a first coil, and a pair of second magnets connected to ends of the first magnet in a manner to extend perpendicular to a protruding direction of the first magnet.

[0015] The receiving pad may include a third magnet opposite the first magnet and configured to protrude toward the first magnet and wound with a second coil.

[0016] The wireless charging system may further include a pad position sensor that detects the positions of the transmitting pad and the receiving pad in a vehicle width direction.

[0017] The double-pole resonance pad structure can be designed to achieve or meet maximum transmission performance in short-range wireless charging.

[0018] An exemplary embodiment of the present disclosure may provide a shape design method of a resonant pad of a wireless charging system for an electric vehicle, which may include: selecting a shape of a pad, analyzing a magnetic circuit, selecting the maximum transmission power depending on a maximum cavity (vertical distance, e.g., air gap) of the transmission and reception pads and a misalignment, selecting a magnetic flux (also called magnetomotive force) NI considering a loss per unit volume, calculating a pole area, selecting a distance between poles, setting the transmission pad asymmetrically in the vehicle width direction, and validating by simulation.

[0019] When selecting the shape of the pad, the transmission pad and the reception pad may be formed asymmetrically, and the transmission pad may have a double-pole resonance pad structure.

[0020] The analysis of the magnetic circuit can be performed by inducing a magnetic equivalent circuit of the transmitting pad and the receiving pad using a valid equation for inductive power transfer (IPT equation for short).

[0021] When selecting the maximum transmission power depending on the maximum cavity and the misalignment of the transmit and receive pads, the maximum transmission power can be obtained as shown in equation 1 below by applying the magnetic inductances L P and Ls and a mutual inductance M. VOCISC=ω(M2 / LS)IP2=ωLPk2IP2

[0022] When selecting the magnetic flux (also magnetomotive force) NI taking into account the loss per unit volume, the magnetic flux can be modeled as in equation 2 below. N1IP=kIgBmax / μ0

[0023] When calculating the pole area, the pole area can be modeled as shown in equation 3 below. A=2Ig Puc / kω(N1IP)2μ0

[0024] When selecting the distance between the poles, the distance between the poles can be determined by FEM simulation.

[0025] When setting the transmission pad asymmetrically in the vehicle width direction, a second magnet can be set on one side so that it is 200 mm longer in the vehicle width direction.

[0026] When validating by simulation, it can be validated whether a desired maximum transmission power (e.g., a maximum target transmission power) is achieved or fulfilled under a misalignment condition of the transmission and reception pads in the vehicle width direction.

[0027] According to an exemplary embodiment of the present disclosure, a transmitting device may be configured by a double-pole pad, and a size of a transverse core of the transmitting pad may be configured asymmetrically to (or wider than) a receiving pad by considering an allowable transverse deviation between a transmitting pad and the receiving pad for wireless charging of an electric vehicle, so that the need for transverse movement of the vehicle for positional alignment of the transmitting and receiving pads can be eliminated or minimized, thereby simplifying a charging system.

[0028] The burden on a customer (especially stress for the customer) for the position alignment of the transmit and receive pads can be minimized, and a system design robust against misalignment can be enabled.

[0029] By maintaining voids between the transmitting and receiving pads at a short distance, the volumes of the transmitting and receiving pads can be reduced, and power transmission capacity can be increased and charging efficiency can be improved.

[0030] An actuator for reducing the cavity between the transmitting and receiving pads can be provided to reduce the installation cost of the transmitting device or the receiving device, and the complexity of the actuator for position control can be minimized by asymmetric design of the transmitting pad.

[0031] The use of a variable element in a receiver-side compensation circuit can be minimized by minimizing a circuit variable change according to a misalignment situation to simplify a receiving device and reduce the cost and volume of the receiving device. Short description of the drawings Fig. 1 is a side view schematically illustrating a wireless charging system for an electric vehicle according to an embodiment of the present disclosure. Fig. 2 is a front view schematically illustrating the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 3 is a diagram schematically illustrating a transmitting and receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 4 is a diagram illustrating a magnetic equivalent circuit model of a transmitting and receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 5 is a flowchart illustrating a molding method of a resonance pad of the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 6 is a diagram illustrating a mutual coupling model equivalent circuit of the transmission pad and the reception pad for magnetic circuit analysis in a molding process of the resonance pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 7 is a graph illustrating a loss per unit core volume for magneto-optical selection in a molding process of a resonant pad in a wireless charging system for an electric vehicle according to an example embodiment of the present disclosure. Fig. 8 is an example diagram for calculating a pole area in a molding process of a resonant pad in a wireless charging system for an electric vehicle according to an example embodiment of the present disclosure. Fig. 9 is an example diagram for selecting a distance between poles in a wireless charging system for an electric vehicle according to an example embodiment of the present disclosure. Fig. 10 to 12 are example diagrams, each for validation by simulation in a molding process of a resonance pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 13 is a diagram illustrating the maximum transmission power in a misalignment situation in a molding process of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 14 is a diagram illustrating a case where only an asymmetric design without an actuator is applied in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 15 is a diagram illustrating a case where an asymmetric design using an actuator is applied in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Fig. 16 is a flowchart illustrating a wireless charging process in the case of using a Y-axis position sensor in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Detailed description of exemplary embodiments

[0032] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings so that an embodiment may be implemented by those skilled in the art. An embodiment of the present disclosure may be implemented in numerous ways and is not necessarily limited to the exemplary embodiments described herein.

[0033] Additionally, in many exemplary embodiments, components having the same configuration in one exemplary embodiment may be described using the same reference numeral, and in other exemplary embodiments, only a component different from an exemplary embodiment may be described.

[0034] The drawings may be schematic and not to scale. The relative dimensions and relationships of parts in the drawings may be exaggerated or reduced for clarity and simplicity, and any dimensions are exemplary only and are not necessarily limiting. In addition, the same structural element or component may be used in two or more drawings to indicate similar characteristics of a like reference numeral. When any part is referred to as being "on" or "over" another part, it may be directly on or over the other parts, or a different part may be present in between.

[0035] Numerous transformations of the diagrams can be expected. Therefore, the exemplary embodiments are not necessarily limited to any particular type of depicted region and may, for example, also include a change in the method of manufacture.

[0036] Hereinafter, exemplary embodiments of the present disclosure, which can provide a wireless charging system for an electric vehicle, will be described in detail with reference to the accompanying drawings.

[0037] Fig. 1 is a side view schematically showing a wireless charging system for an electric vehicle according to an embodiment of the present disclosure. Fig. 2 is a front view schematically showing a wireless charging system for an electric vehicle according to an embodiment of the present disclosure.

[0038] With reference to the Fig. 1 and Fig. 2, the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure may include a transmitting device (e.g., transmitter) 100 installed separately from a vehicle 5 and a receiving device (e.g., receiver) 200 installed within the vehicle 5.

[0039] The transmission device 100 may include a transmission pad (e.g., also called a transmitting pad, transmission unit, or transmission element, for example, a transmitting plate or transmission plate) 10, and the transmission pad 10 may receive energy from a separate energy system from the vehicle 5 to generate an electric field. The receiving device 200 may include a receiving pad (e.g., also called a receiving unit or receiving element) 20 arranged to face the transmission pad 10. The receiving pad 20 may induce a voltage through the electric field generated by the transmission pad 10 to charge a battery of the vehicle 5. The receiving device 200 may include a power conversion circuit that can convert power received by the receiving pad 20 into a DC voltage.

[0040] The wireless charging system for the electric vehicle 5 may further include an actuator 40 installed inside the vehicle 5. The actuator 40 may adjust / adjust a clearance (e.g., a clearance / air gap) d between the transmission pad 10 and the reception pad 20. The actuator 40 may be connected to the reception pad 20 to allow the reception pad 20 to move up and down. The actuator 40 may adjust a clearance d from the transmission pad 10, which is attached to the surface separate from the vehicle 5 (e.g., the ground). The clearance d may, for example, be adjusted to a clearance of about 100 mm or less.

[0041] The wireless charging system for the electric vehicle 5 may further include a parking block (e.g., a stop block, for example, in the form of a stop block) 30. The parking block 30 may be configured to protrude a predetermined height from the ground (e.g., floor). The parking block 30 may be in contact with a tire of the vehicle 5 to limit the forward and / or backward movement of the vehicle 5. The parking block 30 may fix the movement of the vehicle 5 to perform a forward and / or backward alignment of the vehicle 5 between the transmission pad 10 and the reception pad 20.

[0042] Fig. 3 is a diagram schematically illustrating a transmitting and receiving pad of a wireless charging system for an electric vehicle according to an embodiment of the present disclosure.

[0043] With reference to Fig. 3, the transmission pad 10 may be formed asymmetrically to the reception pad 20. The transmission pad 10 may have a double-pole resonant pad structure, and the double-pole resonant pad structure may include a (e.g., U-shaped) first magnet 110 and a pair of second magnets 120 connected to one end of the first magnet 110.

[0044] In the first magnet 110, both ends may be formed to protrude in a height direction of the vehicle 5, and a first coil 130 may be wound on a central portion. When current flows through the first coil 130 wound on the first magnet 110, a magnetic field may be formed in the first magnet 110 and the second magnet 120.

[0045] The second magnets 120 may be rod-shaped and connected to both ends of the first magnet 110 in a manner such that they extend perpendicular to a protruding direction of the first magnet 110. That is, the second magnet 120 may be in a shape extending in a width direction of the vehicle 5.

[0046] The receiving pad 20 may include a (e.g., U-shaped) third magnet 210 opposite the first magnet 110. The third magnet 210 may be configured to protrude toward the first magnet 110 in the height direction of the vehicle 5. A second coil 220 may be wound on a central portion of the third magnet 210. When current flows through the second coil 220, a magnetic field may be formed in the third magnet 210.

[0047] In this case, a double-pole resonant pad structure can be specified to satisfy / achieve maximum transmission power for short-range wireless charging (e.g., short-distance wireless charging). The maximum power transmitted from the transmitting device 100 to the receiving device 200 can be determined by the coupling of the magnetic field of the transmitting pad 10 and the magnetic field of the receiving pad 20. The maximum transmission power can be determined by applying the magnetic inductance L and the mutual inductance M in an inductive power transfer (IPT) mutual bonding model.

[0048] The wireless charging system may further include a pad position sensor that detects the positions of the transmission pad 10 and the reception pad 20 in a vehicle width direction. The pad position sensor and an actuator on the transmission side (e.g., transmitter side) may be used together to reduce the core size of the transmission pad 10 in the vehicle width direction, mitigate the asymmetry of the transmission pad 10, and reduce volume and cost.

[0049] Fig. 4 is a diagram illustrating a magnetic equivalent circuit model of a transmitting and receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0050] With reference to the Fig. 3 and Fig. 4, the maximum transmission power of the transmission and reception pads 10 and 20 can be calculated using the Fig. 3 shown placements of the transmission and reception pads 10 and 20 by the magnetic equivalent circuit model of Fig. 4 be replaced.

[0051] In the magnetic equivalent circuit of Fig. 4, an Ampere primary circuit law and a Faraday law can be applied to generate a magnetic flux which varies with time by the current of the coils 130 and 220, and to induce a counter electromotive force by the time-varying magnetic flux.

[0052] Fig. 5 is a flowchart illustrating a molding method of a resonance pad of the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0053] With reference to Fig. 5, first, schematic shapes of the pads 10 and 20 may be selected to design the shape of the resonant pad of the wireless charging system (process S101). In one embodiment of the present disclosure, the shapes of the transmitting and receiving pads 10 and 20 may be selected, which may be formed by a transmitting pad 10 having a double-pole resonant pad structure including the first magnet 110 and the second magnet 120, and a receiving pad 20 having the third magnet 210 arranged to oppose the transmitting pad 10.

[0054] After that, a magnetic circuit can be analyzed (process S102). In this case, the analysis of the magnetic circuit can be performed by a magnetic equivalent circuit induction model of the transmitting and receiving pads 10 and 20 using a governing IPT equation, which is given in the Fig. 3 and Fig. 4. When current I flows after coils 130 and 220 are wound on an iron core with N turns, a magnetic flux f can be generated in the iron core. The magnetic flux can be rotated through the iron core, i.e., form a closed circuit. The magnetic flux can flow along the iron core and can be proportional to NI (i.e., N multiplied by I). NI can be referred to as the magnetic flux. The flow of the magnetic flux can be interrupted by the magnetic resistance Rm. That is, the magnetic flux is inversely proportional to the magnetic resistance and can be proportional to the magnetic flux F.

[0055] Thereafter, the maximum transmission power can be selected based on a maximum cavity and a misalignment (e.g., misalignment) of the transmission and reception pads 10 and 20 (process S103).

[0056] Fig. 6 is a diagram illustrating a mutual coupling model equivalent circuit of the transmission pad and the reception pad for magnetic circuit analysis in a molding process of the resonance pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0057] The maximum transmission power can be achieved by applying the magnetic inductances L P and L Sand the mutual inductances M can be modeled in the mutual coupling model. The maximum transmission power of the transmitting and receiving pads 10 and 20 can be determined by magnetic field coupling between the transmitting and receiving pads 10 and 20, and the maximum transmission power of the transmitting and receiving pads 10 and 20 can be obtained by multiplying a voltage Voc and a current Isc. This can be expressed by Equation 1 below. VOCISC=ω(M2 / LS)IP2=ωLPk2IP2

[0058] The flow rate NI can then be selected taking into account the losses per unit volume (process S104).

[0059] Fig. 7 is a diagram illustrating a loss per unit core volume for the selection of the magnetic flux in the molding process of the resonant pad in the wireless charging system for an electric vehicle according to an embodiment of the present disclosure.

[0060] With reference to Fig. 4 and Fig. 7, a core magnetic flux density ∅1 through the current on the side of the transmission device 100 can be a sum of ∅1 and ∅ l1 and this becomes a value of B avg * A, and this becomes (N1I1 / 2kl g )* µ0A. In this case, B is equal to (N1I1 / 2kl g )* µ0.

[0061] The loss per unit volume P v can produce about 200 kW / m 3 with natural heat dissipation and about 500 kW / m 3 with active heat dissipation, as in Fig. 7. In one embodiment of the present disclosure, B max equal to 150 mT.

[0062] The current flow can be modeled as in equation 2 below. N1IP=kIgBmax / μ0

[0063] The flow rate, which takes into account the loss per unit volume, can be calculated by inserting the value of B max into equation 2 above.

[0064] The pole area can then be calculated (process S105).

[0065] Fig. 8 is an example diagram for calculating a pole area in the molding process of a resonance pad in a wireless charging system for an electric vehicle according to an example embodiment of the present disclosure.

[0066] The pole area can be modeled using equation 3 below. A=2Ig Puc / kω(N1IP)2μ0

[0067] In this case, k can represent a minimum coupling factor or bonding coefficient in a given cavity d and under misalignment, and a maximum transmission performance can be corrected even under a poor coupling situation. The value of N1I P can take the value of the current flow selected above.

[0068] A distance between the poles can then be selected (process S106).

[0069] Fig. 9 is an example diagram for selecting a distance between the poles in the molding process of the resonance pad of the wireless charging system for an electric vehicle according to an example embodiment of the present disclosure.

[0070] With reference to Fig. 9, the case where the pole area is constant represents a change in the transmission power depending on a distance between the poles. There may be a tendency according to which, as the distance between the poles becomes smaller, the magnetic stray resistance R lk increases, a coupling factor k decreases, and the transmission power is reduced. However, since the distance between the poles cannot be chosen to be excessively large, the shape of the resonance pad can be designed using a FEM simulation.

[0071] Thereafter, the transmission pad 10 may be set asymmetrically in a vehicle width direction (operation S107).

[0072] With reference to Fig. 3 and Fig. 4 a magnetic flux ∅ l1on the transmission device 100 side may be increased due to the reduction in magnetic resistance. An inductance L1 on the transmission device 100 side and a leakage inductance may increase.

[0073] A magnetic resistance Rm between the side of the transmitting device 100 and the side of the receiving device 200 can be almost constant. The mutual magnetic fluxes ∅ 21 and ∅ 11 can be maintained, and the maximum transmission power selected in the above embodiment can be maintained.

[0074] Validation can then be performed using an FEM simulation (FEM = Finite Element Method) (process S108). During validation using the FEM simulation (process S108), it can be validated whether a desired maximum transmission power (e.g., a maximum target transmission power) is met given the misalignment condition of the transmission pad 10 and the reception pad 20 in the vehicle width direction.

[0075] Fig. 10 to 12 are example diagrams, and each may be used for validation by simulation in the molding process of the resonant pad in the wireless charging system for an electric vehicle according to an example embodiment of the present disclosure.

[0076] The first magnet 110, the first coil 130, and the second magnet 120 may be arranged as the transmission pad 10. The second coil 220 may be arranged to oppose the second magnet 120. The third magnet 210 may be arranged on the second coil 220 as the reception pad 20. The transmission pad 10 and the reception pad 20 may be set in an asymmetrical shape.

[0077] Furthermore, in the transmission device 100, an asymmetric design of the transmission pad 10 in the Y-axis direction can be performed according to the misalignment condition in the vehicle width direction (Y-axis direction misalignment condition).

[0078] For example, the transmission device 100 in the Fig. 10 and Fig. 11, the Y-axis misalignment condition of + / - 100 mm may be increased by 200 mm in the Y-axis direction. That is, the pole face of the transmitter 100 may be set to 25 mm in the X-axis direction and 300 mm in the Y-axis direction, and the pole face of the receiver 200 may be set to 25 mm in the X-axis direction and 100 mm in the Y-axis direction. Furthermore, in the Z-axis direction, the pole face of the transmitter 100 may be set to 75 mm and the pole face of the receiver 200 may be set to 50 mm.

[0079] The asymmetric misalignment condition, the inductances L p and L s according to the Y-axis misalignment and the mutual inductance M can be derived.

[0080] In a Fig. 12 shows the worst case misalignment condition to check whether the maximum transmission power can be achieved or fulfilled. Fig. 12, under a condition where the pole area of ​​the transmission device is 100 + / - 25 mm in the X-axis direction, + / - 100 mm in the Y-axis direction and 10 mm in the Z-axis direction, it can be validated whether the desired maximum transmission power (e.g. 10 kVA) can be achieved.

[0081] Fig. 13 is a diagram illustrating the maximum transmission power in a misalignment situation in the molding process of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0082] As in Fig. 13, it can be seen that when a cavity d of 10 mm is formed between the transmitting pad 10 and the receiving pad 20, the targeted maximum transmission power (e.g., 10 kVA) can be achieved in the case of regulation to 12.5 mm in the X-axis direction and 50 mm in the Y-axis direction (e.g., misalignment = 1) and in the case of + / - 25 mm in the X-axis direction and + / - 100 mm in the Y-axis direction (e.g., misalignment = 2) in terms of the maximum transmission power according to a misalignment degree.

[0083] Accordingly, in terms of a pad specification for a maximum design, a receiving device area of ​​200 by 2500 mm 2 and the receiving device 200 can be set to 100 mm in the X-axis direction, 100 mm in the Y-axis direction and 50 mm in the Z-axis direction, and the area of ​​the transmitting device 100 can be set to 2500 mm, for example. 2and the transmission device 100 can be set to 100 mm in the X-axis direction, 300 mm in the Y-axis direction and 75 mm in the Z-axis direction.

[0084] Fig. 14 is a diagram illustrating a case where only an asymmetric design without an actuator is applied in the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure, and Fig. 15 is a diagram illustrating a case where the asymmetric design using the actuator is applied in the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0085] As in Fig. 14, a core size L core in the Y-axis direction when only the asymmetric structure without the actuator 40 is used. However, if, as in Fig. 15, the control in the Y-axis direction is possible using the actuator 40, the core size in the Y-axis direction can be reduced, and as a result, the asymmetry of the transmission device 100 can be reduced and the volume and cost can be reduced.

[0086] Fig. 16 is a flowchart illustrating a wireless charging process in the case of using a Y-axis position sensor in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0087] During the communication readiness of a transmitting device 100 and a receiving device 200 (process S201), if it is confirmed that the communication connection is established (process S202), a pad position sensor may be activated and a vehicle 5 may be on standby for entering a charging system (process S203).

[0088] Thereafter, the vehicle 5 can enter and it can be checked whether the vehicle 5 enters within a position range of the pad position sensor (process S204).

[0089] If it is confirmed that the vehicle 5 enters the position range of the pad position sensor, a horizontal axis position Y va of the receiving pad 20 and a horizontal axis movement distance Y ga of the transmission device 100 can be calculated (operation S205), and it can be checked whether the transmission device 100 is movable (operation S206). If an absolute value of the horizontal axis movement distance Y ga of the transmission device 100 is smaller than a maximum horizontal axis movement distance Y ga,max of the transfer device 100, a movement in the Y-axis direction of the transfer device 100 and a loading process can be initiated (process S207).

[0090] By using the Y-axis position sensor, the asymmetry of the transmission device 100 can be reduced and the volume and cost can be reduced due to the reduction of the core size in the Y-axis direction to similar to that of the actuator 40.

[0091] As described above, according to an embodiment of the present disclosure, a transmitting device may be configured by a double-pole pad, and a size of a transverse core of the transmitting pad may be configured asymmetrically to (or wider than) a receiving pad by considering an allowable transverse deviation between a transmitting pad and the receiving pad for wireless charging of an electric vehicle, so that the need for transverse movement of the vehicle for positional alignment of the transmitting and receiving pads can be eliminated or minimized, thereby potentially simplifying a charging system.

[0092] Using an embodiment, the burden (particularly stress for the customer) that a customer feels for the positional alignment of the transmit and receive pads can be minimized and a system design robust to misalignment can be enabled.

[0093] Using an embodiment, by maintaining a cavity between the transmitting and receiving pads at a short distance, the volume of the transmitting and receiving pads can be reduced and the power transmission capability can be increased and the charging efficiency can be improved.

[0094] Using an embodiment, an actuator may be provided to reduce the cavity between the transmitting and receiving pads to reduce the installation cost of the transmitting device or the receiving device, and the complexity of the actuator for position control may be minimized by asymmetric design of the transmitting pad.

[0095] Using an embodiment, the use of a variable element in a receiver-side compensation circuit can be minimized by minimizing a circuit variable change according to a misalignment situation to simplify a receiving device and to reduce cost and volume of the receiving device.

[0096] Although the present disclosure has been described in connection with the exemplary embodiments presently contemplated, it is to be understood that the embodiments of the present disclosure are not necessarily limited to the disclosed exemplary embodiments. On the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

[1] Wireless charging system for an electric vehicle (5), comprising: a transmission device (100) having a transmission pad (10) installed outside the vehicle (5), wherein the transmission device (100) is configured to generate an electromagnetic field by receiving energy, and a receiving device (200) comprising a receiving pad (20) installed inside the vehicle (5), wherein the receiving pad (20) is arranged and configured to face the transmitting pad (10), wherein the receiving device (200) is configured to induce a voltage by means of the electromagnetic field generated by the transmitting pad (10) and to charge a battery of the vehicle (5), wherein the transmitting pad (10) is configured to transmit a predetermined output power even if the transmitting pad (10) is configured to be asymmetrical to the receiving pad (20) in a width direction of the vehicle. [2] The system of claim 1, wherein the receiving device (200) comprises a power conversion circuit configured to convert a power received by the receiving pad (20) into a DC voltage. [3] The system according to claim 1 or 2, further comprising an actuator (40) installed in the vehicle (5), the actuator (40) being configured to adjust a vertical distance between the transmitting pad (10) and the receiving pad (20). [4] The system of claim 3, wherein the actuator (40) is configured to set the vertical distance between the transmitting pad (10) and the receiving pad (200) as an intermediate distance of 100 mm or less. [5] System according to one of claims 1 to 4, further comprising a parking block (30) installed separately from the vehicle (5), wherein the parking block (30) is adapted to adjust a longitudinal orientation of the vehicle (5). [6] The system according to any one of claims 1 to 5, wherein the transmission pad (10) comprises a double-pole resonant pad structure, and wherein the double-pole resonant pad structure comprises: a first magnet (110) which is designed to protrude in a height direction of the vehicle (5) and which is wound with a first coil (130), and a pair of second magnets (120) connected to ends of the first magnet (110) in a manner that protrudes further in the height direction. [7] The system of claim 6, wherein the receiving pad (20) comprises a third magnet (210), the third magnet (210) being configured to be disposed opposite the first magnet (110) and to protrude toward the first magnet (110), and the third magnet (210) being wound with a second coil (220). [8] The system of claim 7, wherein the double-pole resonant pad structure is configured to achieve a predetermined transmission power for short-range wireless charging. [9] The system according to any one of claims 1 to 8, further comprising a pad position sensor configured to detect the relative positions of the transmitting pad (10) and the receiving pad (20) in a vehicle width direction. [10] A molding method of a resonance pad of a wireless charging system for an electric vehicle, comprising: Selecting (S101) shapes of a transmission pad (10) and a reception pad (20), Analyzing (S102) a magnetic circuit having the transmission pad (10) and the reception pad (20), Selecting (S103) a maximum transmission power based on a maximum vertical distance between the transmission pad (10) and the reception pad (20) and based on a horizontal misalignment between the transmission pad (10) and the reception pad (20), Selecting (S104) a flow rate taking into account a loss per unit volume, Calculating (S105) a pole face, Selecting (S106) a first distance between poles, Setting (S107) the transmission pad (10) asymmetrically in a vehicle width direction relative to the reception pad (20), and Validate (S108) through a simulation. [11] The method according to claim 10, wherein selecting (S101) the shapes of the transmission pad (10) and the reception pad (20) comprises: selecting the shapes of the transmission pad (10) and the reception pad (20) such that the shape of the transmission pad (10) is asymmetrical to the reception pad (20), wherein the transmission pad (10) has a double-pole resonant pad structure. [12] Method according to claim 10 or 11, wherein the analyzing (S102) of the magnetic circuit is carried out by inducing a magnetic equivalent circuit of the transmission pad (10) and the reception pad (20) by means of a valid equation for inductive power transfer, IPT equation for short. [13] The method according to any one of claims 10 to 12, wherein selecting (S103) the maximum transmission power comprises modeling the maximum transmission power using equation 1: VOCISC=ω(M2 / LS)IP2=ωLPk2IP2 where Voc is voltage, Isc is current, ω is the frequency of the alternating current, M is the mutual inductance, L P is the self-inductance of a primary coil with respect to the transmission pad (810), Ls is the self-inductance of a secondary coil with respect to the reception pad (20), I P is a current in the primary coil and k is a coupling factor between the primary coil and the secondary coil. [14] Method according to one of claims 10 to 13, wherein in selecting (S104) the flow rate taking into account the loss per unit volume, the flow rate is modeled as in equation 2: N1IP=kIgBmax / μ0 where N1 is a number of turns of a primary coil relative to the transmission pad (10), I P a current in the primary coil, I g is a given vertical distance between the transmission pad (10) and the reception pad (20), k is a minimum coupling factor in the given vertical distance between the transmission pad (10) and the reception pad (20) as well as for a misalignment situation, B max is a maximum magnetic flux density representing a peak magnetic field strength in an air gap between the transmitting pad (10) and the receiving pad (20), and µ0 is a constant representing the permeability of the free space at the air gap. [15] Method according to one of claims 10 to 14, wherein in calculating (S105) the pole area, the pole area is modeled as in equation 3: A=2Ig Puc / kω (N1IP)2μ0 where A is a cross-sectional area through which the magnetic flux passes, l gis a given vertical distance between the transmission pad (10) and the reception pad (20), k is a minimum coupling factor in the given vertical distance between the transmission pad (10) and the reception pad (20) and for a misalignment situation, P uc is the uncoupled power, which represents the power transmitted when the transmitting pad (10) and the receiving pad (20) are not ideally coupled due to misalignment, separation, or misalignment and separation, ω is the frequency of the alternating current, N1 is the number of turns of a primary coil with respect to the transmitting pad (10), I P is the current in the primary coil, and µ0 is a constant representing the permeability of the free space in an air gap between the transmitting pad (10) and the receiving pad (20). [16] Method according to one of claims 10 to 15, wherein, when selecting (S106) the first distance between the poles, the first distance between the poles is determined by a finite element method simulation, FEM simulation for short. [17] The method according to any one of claims 10 to 16, wherein the setting (S107) of the transmission pad (10) asymmetrically in the vehicle width direction comprises: Fixing a second magnet (120) on one side such that it is 200 mm longer in the vehicle width direction. [18] The method according to any one of claims 10 to 17, wherein the validating (S108) by the simulation comprises: validating whether a target maximum transmission power is achieved under a misalignment condition of the transmission pad (10) and the reception pad (20) in the vehicle width direction. [19] Wireless charging system for a vehicle (5), comprising: a transmission device (100) comprising a transmission pad (10) adapted to be installed separately from the vehicle (5), wherein the transmission device (100) is adapted to generate an electromagnetic field by receiving energy, and a receiving device (200) comprising a receiving pad (20) installed inside the vehicle (5), wherein the receiving pad (20) is configured to be arranged so as to face the transmitting pad (10) while the vehicle is located above the transmitting device (100), wherein the receiving device (200) is configured to induce a voltage by means of the electromagnetic field generated by the transmitting pad (10) and to charge a battery of the vehicle (5), wherein the transmitting pad is wider than the receiving pad (20) in a vehicle width direction. [20] The system of claim 19, wherein the transmission pad (10) comprises a double-pole resonant pad structure, and wherein the double-pole resonant pad structure comprises: a substantially U-shaped first magnet (110) which is designed to protrude in a height direction of the vehicle (5), the first magnet (110) being wound with a first coil (130), and a pair of substantially rod-shaped second magnets (120) connected to the ends of the first magnet (110) in such a way as to protrude further in the height direction, the second magnets (120) having a first width in the vehicle width direction, and wherein the receiving pad (20) has a substantially U-shaped third magnet (220), wherein the third magnet (220) is configured to be arranged opposite the first magnet (110) and to protrude towards the first magnet (110) while the receiving device (200) is located above the transmitting device (100), wherein the third magnet (210) is wound with a second coil (220), and wherein a measuring distance across protruding tips of the third magnet (210) in the vehicle width direction has a second width, and wherein the first width is greater than the second width.

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