Wireless charging system for vehicle and shape design method of resonance pad thereof

Abstract

The invention relates to a wireless charging system for a vehicle and a shape design method of a resonance pad thereof. The wireless charging system may include: a transmitter including a transmitting pad mounted separately from a vehicle and configured to generate an electromagnetic field by receiving energy; and a receiver including a receiving pad mounted inside the vehicle and configured to face the transmitting pad, and configured to induce a voltage through an electromagnetic field generated by the transmitting pad and charge a battery of the electric vehicle, and the transmitting pad may be provided so as to transmit the maximum output even if the transmitting pad is formed asymmetrical with the receiving pad in the width direction of the vehicle.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2023 - 0183028, filed with the Korean Intellectual Property Office on December 15, 2023, which is incorporated herein by reference. Technical field

[0003] The present disclosure relates to a wireless charging system for an electric vehicle. Background art

[0004] Generally, a wireless charging system for an electric vehicle consists of a transmitter and a receiver. The transmitter is installed outside the vehicle including a transmitting pad, and the receiver includes a receiving pad and is installed inside the vehicle.

[0005] The transmitter converts the energy supplied from the system into a high - frequency AC signal through a switching device and transmits the high - frequency AC signal to the transmitting pad. A time - varying magnetic field generated by the transmitting pad induces a voltage in the receiving pad. A power conversion circuit installed on the receiver converts the power received through the receiving pad into a DC voltage to charge a high - voltage battery. In this case, the magnitude and efficiency of the wirelessly transmitted power vary according to the alignment state (vertical direction Z, longitudinal direction X, and lateral direction Y) between the transmitting pad and the receiving pad.

[0006] In the prior - art wireless charging system for an electric vehicle, the receiving pad is mainly installed at the lower part of the vehicle. In this case, the alignment state between the transmitting pad and the receiving pad can vary according to the parking state / cargo loading state, and this results in deviations in wireless charging performance (such as output, efficiency, etc.).

[0007] Even if alignment deviations exist within the allowable vertical and longitudinal / lateral distance ranges, the volume / weight / cost / complexity of the resonant pad and the compensation circuit increase for energy transfer.

[0008] Therefore, a system has been proposed that adjusts the vertical distance between the transmitting pad and the receiving pad by coupling an actuator to the transmitting pad and keeps the vertical distance between the transmitting pad and the receiving pad constant, or a system that keeps the vertical distance between the transmitting pad and the receiving pad constant by coupling an actuator to the receiving pad and raising the actuator coupled to the receiving pad. However, when considering longitudinal / lateral alignment errors, position control of up to 3 axes is required, so there is a problem that the complexity of the actuator increases significantly. Summary of the invention

[0009] The present disclosure relates to a wireless charging system for an electric vehicle, and more particularly, to a wireless charging system for an electric vehicle including a bipolar resonant pad having an asymmetric structure.

[0010] Accordingly, embodiments of the present disclosure can provide a wireless charging system for an electric vehicle, wherein, when the vehicle is aligned for wireless charging, a position error can occur, and wherein, the transmitter can be configured by a bipolar pad, and by considering the lateral allowable deviation between the transmitting pad and the receiving pad, the size of the lateral core can be configured asymmetrically with respect to the receiving pad.

[0011] Exemplary embodiments of the present disclosure provide a wireless charging system for an electric vehicle, the wireless charging system can include: a transmitter, including a transmitting pad separately installed from the vehicle and generating an electromagnetic field by receiving energy; and a receiver, including a receiving pad installed inside the vehicle and configured to face the transmitting pad and inducing a voltage by the electromagnetic field generated by the transmitting pad and charging the battery, wherein, the transmitting pad can be configured to transmit the maximum output even if the transmitting pad is formed asymmetrically with respect to the receiving pad in the width direction of the vehicle.

[0012] The receiver can include: a power conversion circuit for converting the power received through the receiving pad into a DC voltage.

[0013] The wireless charging system can further: include an actuator, installed inside the vehicle, and adjusting the gap (vertical distance) between the transmitting pad and the receiving pad.

[0014] The gap between the transmitting pad and the receiving pad can be adjusted to an interval of 100 mm or less.

[0015] The wireless charging system can further include: a parking block separately installed from the vehicle, and adjusting the longitudinal (x-axis) alignment of the vehicle.

[0016] The transmitting pad can have a bipolar resonant pad structure, and the bipolar resonant pad structure can include: a first magnet, formed to protrude in the height direction of the vehicle and wound with a first coil; and a pair of second magnets, coupled to the ends of the first magnet in a form perpendicular to the protruding direction of the first magnet.

[0017] The receiving pad can include a third magnet, which faces the first magnet and is formed to protrude toward the first magnet, and a second coil is wound around the third magnet.

[0018] The wireless charging system can further include: a pad position sensor for sensing the positions of the transmitting pad and the receiving pad in the width direction of the vehicle.

[0019] The bipolar resonant pad structure can be designed to meet the maximum transmission power during short-distance wireless charging.

[0020] An exemplary embodiment of the present disclosure may provide a method for designing the shape of a resonant pad for a wireless charging system of an electric vehicle. The shape design method may include: selecting the shape of the pad; analyzing the magnetic circuit; selecting the maximum transmission power considering the maximum air gap (vertical distance) and misalignment between the transmitting pad and the receiving pad; selecting the magnetomotive force NI considering the loss per unit volume; calculating the pole area; selecting the distance between the poles; asymmetrically arranging the transmitting pad in the vehicle width direction; and verifying through simulation.

[0021] When selecting the shape of the pad, the transmitting pad and the receiving pad may be formed asymmetrically, and the transmitting pad may have a bipolar resonant pad structure.

[0022] The analysis of the magnetic circuit may be performed by inductively coupling the magnetic equivalent circuits of the transmitting pad and the receiving pad through the inductive power transfer (IPT) regular equations.

[0023] When selecting the maximum transmission power considering the maximum air gap and misalignment between the transmitting pad and the receiving pad, the maximum transmission power may be modeled as Equation 1 below by applying the magnetic inductances L P and L S and the mutual inductance M.

[0024] [Equation 1]

[0025] V OC I SC = ω(M 2 / L S )I P 2 = ωL P k 2 I P 2 .

[0026] When selecting the magnetomotive force NI considering the loss per unit volume, the magnetomotive force may be modeled as Equation 2 below.

[0027] [Equation 2]

[0028] N1I P = kl g B max / μ0.

[0029] When calculating the pole area, the pole area may be modeled as Equation 3 below.

[0030] [Equation 3]

[0031] A = 2l g P uc / kω(N1I P )2μ0.

[0032] When selecting the distance between the poles, the distance between the poles can be set through FEM simulation.

[0033] When the transmitting pad is asymmetrically arranged in the vehicle width direction, the second magnet on one side can be set to be 200 mm long in the vehicle width direction.

[0034] When verifying through simulation, it can be verified whether the target maximum transmission power is satisfied under the misalignment condition of the transmitting pad and the receiving pad in the vehicle width direction.

[0035] According to an exemplary embodiment of the present disclosure, the transmitter can be configured with a bipolar pad, and by considering the lateral allowable deviation between the transmitting pad and the receiving pad for wireless charging of an electric vehicle, the size of the lateral core of the transmitting pad can be configured asymmetrically (or wider than the receiving pad) relative to the receiving pad. Therefore, for the position alignment of the transmitting pad and the receiving pad, the need for lateral movement of the vehicle can be eliminated or minimized, thereby simplifying the charging system.

[0036] The stress of the customer regarding the position alignment of the transmitting pad and the receiving pad can be minimized, and a system design that is robust to misalignment can be achieved.

[0037] By keeping the gap between the transmitting pad and the receiving pad at a short distance, the volume of the transmitting pad and the receiving pad can be reduced, the power transmission capacity can be increased, and the charging efficiency can be improved.

[0038] An actuator for reducing the gap between the transmitting pad and the receiving pad can be provided to reduce the installation cost of the transmitter or the receiver, and the complexity of the actuator for position control can be minimized through the asymmetric design of the transmitting pad.

[0039] By minimizing the minimum variable change of the circuit according to the misalignment situation, the use of variable elements in the receiver-side compensation circuit can be minimized to simplify the receiver structure, reduce costs, and reduce the volume of the receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a side view schematically showing a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0041] Figure 2 is a front view schematically showing a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0042] Figure 3 is a view schematically showing a transmitting pad and a receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0043] Figure 4It is a diagram showing a magnetic equivalent circuit model of a transmitting pad and a receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0044] Figure 5 It is a flowchart showing a method for designing the shape of a resonant pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0045] Figure 6 It is a diagram showing a mutual combination model equivalent circuit of a transmitting pad and a receiving pad for magnetic circuit analysis in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0046] Figure 7 It is a diagram showing the loss per unit volume of each core for magnetic motive force selection in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0047] Figure 8 It is an example diagram for calculating the pole area in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0048] Figure 9 It is an example diagram for selecting the distance between poles in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0049] Figures 10 to 12 It is an example diagram, where each example diagram is used to verify through simulation in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0050] Figure 13 It is a diagram showing the maximum transmission power in the case of misalignment in a method for designing the shape of a resonant pad in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0051] Figure 14 It is a diagram showing the case of applying only an asymmetric design without applying an actuator in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0052] Figure 15 It is a diagram showing the case of applying an asymmetric design by using an actuator in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0053] Figure 16It is a flowchart showing a wireless charging process in a wireless charging system for an electric vehicle using a Y-axis position sensor according to an exemplary embodiment of the present disclosure. Detailed Embodiment

[0054] Hereinafter, exemplary embodiments of the present disclosure will be described more fully with reference to the accompanying drawings, so that those skilled in the art can implement the embodiments. The embodiments of the present disclosure can be implemented in various different forms and are not necessarily limited to the exemplary embodiments described herein.

[0055] In addition, in various exemplary embodiments, the same reference numerals may be used to describe components having the same configuration in the exemplary embodiments, and in other exemplary embodiments, only the components different from the exemplary embodiments may be described.

[0056] The drawings may be schematic and not drawn to scale. In the drawings, for clarity and convenience, the relative sizes and ratios of the components in the drawings may be enlarged or reduced in their sizes, and any size may be merely an example and not necessarily restrictive. In addition, the same structural elements or components in two or more drawings may be used to show similar characteristics with the same reference numerals. When any part of the other part or is referred to as "on...", "above...", it may be directly on the other part or directly above the other part or there may be different parts in between.

[0057] Different transformations of these figures can be expected. Therefore, the exemplary embodiments are not necessarily limited to the specific forms of the shown regions, and for example, may also include modifications in manufacturing forms.

[0058] Hereinafter, exemplary embodiments of the present disclosure that can provide a wireless charging system for an electric vehicle will be described in detail with reference to the accompanying drawings.

[0059] Figure 1 It is a side view schematically showing a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure. Figure 2 It is a front view schematically showing a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0060] Refer to Figure 1 and Figure 2 , a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure may include: a transmitter 100, separately installed from the vehicle 5; and a receiver 200, installed inside the vehicle 5.

[0061] The transmitter 100 may include a transmitting pad 10, and the transmitting pad 10 may receive energy from a power system separate from the vehicle 5 to generate an electric field. The receiver 200 may include a receiving pad 20 arranged to face the transmitting pad 10. The receiving pad 20 may induce a voltage through the electric field generated by the transmitting pad 10 to charge the battery of the vehicle 5. The receiver 200 may include a power conversion circuit that may convert the power received through the receiving pad 20 into a DC voltage.

[0062] 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 the gap d between the transmitting pad 10 and the receiving pad 20. The actuator 40 may be connected to the receiving pad 20 to allow the receiving pad 20 to move up and down. The actuator 40 may adjust the gap d from the transmitting pad 10 fixed to a surface separate from the vehicle 5. For example, the gap d may be adjusted to an interval of about 100 mm or less.

[0063] The wireless charging system for the electric vehicle 5 may further include a parking block 30. The parking block 30 may be configured in the form of protruding from the ground at a predetermined height. The parking block 30 may contact the tires 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 forward and / or backward alignment of the vehicle 5 between the transmitting pad 10 and the receiving pad 20.

[0064] Figure 3 is a diagram schematically showing a transmitting pad and a receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0065] Reference Figure 3 , the transmitting pad 10 may be formed asymmetrically with respect to the receiving pad 20. The transmitting pad 10 may have a bipolar resonant pad structure, and the bipolar resonant pad structure may include a first magnet 110 and a pair of second magnets 120 coupled to the ends of the first magnet 110.

[0066] In the first magnet 110, two ends may be formed to protrude in the height direction of the vehicle 5, and a first coil 130 may be wound around the central portion. When current flows through the first coil 130 wound around the first magnet 110, a magnetic field may be formed in the first magnet 110 and the second magnets 120.

[0067] The second magnets 120 may be bars coupled to the two ends of the first magnet 110 in a form extending vertically to the protruding direction of the first magnet 110. That is, the second magnets 120 may be in a form extending in the width direction of the vehicle 5.

[0068] The receiving pad 20 may include a third magnet 210 opposite to the first magnet 110. The third magnet 210 may be formed to protrude toward the first magnet 110 in the height direction of the vehicle 5. The second coil 220 may be wound around the central portion of the third magnet 210. When an electric current flows through the second coil 220, a magnetic field may be formed in the third magnet 210.

[0069] In this case, the bipolar resonant pad structure may be specified to satisfy the maximum transmission power during short-distance wireless charging. The maximum power transmitted from the transmitter 100 to the receiver 200 may 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 may be determined by applying the magnetic inductance L and the mutual inductance M in the inductive power transfer (IPT) engagement model.

[0070] The wireless charging system may further include a pad position sensor that senses the positions of the transmitting pad 10 and the receiving pad 20 in the vehicle width direction. The pad position sensor and the actuator on the transmitter side may be jointly used to reduce the core size of the transmitting pad 10 in the vehicle width direction, mitigate the asymmetry of the transmitting pad 10, and reduce the volume and cost.

[0071] Figure 4 is a diagram showing a magnetic equivalent circuit model of a transmitting pad and a receiving pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0072] Reference Figure 3 and Figure 4 , in order to calculate the maximum transmission power of the transmitting pad 10 and the receiving pad 20, Figure 3 the placement form of the transmitting pad 10 and the receiving pad 20 shown may be Figure 4 replaced by the magnetic equivalent circuit model of

[0073] In Figure 4 the magnetic equivalent circuit of , Ampere's primary circuit law and Faraday's law may be applied to generate a magnetic flux that varies with time according to the currents in the coils 130 and 220, and an electromotive force is induced by the magnetic flux that varies with time.

[0074] Figure 5 is a flowchart showing a method for designing the shape of a resonant pad of a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0075] Reference Figure 5, First, the schematic shapes of pads 10 and 20 can be selected to design the shape of the resonant pads of the wireless charging system (operation S101). In an exemplary embodiment of the present disclosure, the shapes of the transmitting pad 10 and the receiving pad 20 can be selected, and the shape can be composed of a transmitting pad 10 having a bipolar resonant pad structure including a first magnet 110 and a second magnet 120 and a receiving pad 20 including a third magnet 210 arranged to face the transmitting pad 10.

[0076] Thereafter, the magnetic circuit can be analyzed (operation S102). In this case, the magnetic circuit analysis can be performed by Figure 3 and Figure 4 The IPT ruling equation shown is executed by the magnetic equivalent circuit induction model of the transmitting pad 10 and the receiving pad 20. When a current I flows after the coils 130 and 220 are wound around the iron core N turns, a magnetic flux f can be generated in the iron core. The magnetic flux can rotate through the iron core (i.e., a closed circuit). The magnetic flux can flow along the iron core and can be proportional to NI. NI can be referred to as the magnetomotive force. The flow of the magnetic flux can be interrupted by the magnetic resistance Rm. That is, the magnetic flux can be inversely proportional to the magnetic resistance and can be proportional to the magnetomotive force F.

[0077] Thereafter, the maximum transmission power can be selected based on the maximum gap and misalignment between the transmitting pad 10 and the receiving pad 20 (operation S103).

[0078] Figure 6 is a diagram showing the mutual combination model equivalent circuit of the transmitting pad and the receiving pad for magnetic circuit analysis in the shape design method of the resonant pad in the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0079] The maximum transmission power can be modeled by applying the magnetic inductances L P and L S and the mutual inductance M in the mutual engagement model. The maximum transmission power between the transmitting pad 10 and the receiving pad 20 can be determined by the magnetic field engagement between the transmitting pad 10 and the receiving pad 20, and the maximum transmission power of the transmitting pad 10 and the receiving pad 20 can be obtained by multiplying the voltage V oc and the current I sc . This can be represented by the following formula 1.

[0080] [Formula 1]

[0081] V OC I SC =ω(M 2 / L S )I P 2 =ωL P k 2 IP 2 。

[0082] Thereafter, the magnetomotive force NI per unit volume loss can be considered (operation S104).

[0083] Figure 7 is a diagram showing the loss per unit volume of the core for magnetomotive force selection in the shape design method of the resonance pad in the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0084] Refer to Figure 4 and Figure 7 , the core magnetic flux density of the current on the transmitter 100 side can be and the sum of, and this becomes the value B avg *A, and this becomes (N1I1 / 2kl g )*μ0A. In this case, B is (N1I1 / 2kl g )*μ0.

[0085] The loss P per unit volume v can be about 200 kW / m during natural heat dissipation 3 , and can be about 500 kW / m during active heat dissipation 3 , as Figure 7 shown. In the case of the embodiment of the present disclosure, B max can be 150 mT.

[0086] The magnetomotive force can be modeled as Equation 2 below.

[0087] [Equation 2]

[0088] N1I P = kl g B max / μ0.

[0089] The magnetomotive force considering the loss per unit volume can be selected by substituting the value of B max into Equation 2 above.

[0090] Thereafter, the pole area can be calculated (operation S105).

[0091] Figure 8 is an example diagram for calculating the pole area in the shape design method of the resonance pad in the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0092] The pole area can be modeled as Equation 3 below.

[0093] [Equation 3]

[0094] A = 2l g P uc / kω(N1I P )2μ0。

[0095] In this case, k can represent the minimum coupling coefficient in the given pore d and misalignment situation, and can correct the maximum transmission power even in the worst coupling situation. N1I P The value of can adopt the magnetomotive force value selected above.

[0096] Thereafter, the distance between the poles can be selected (operation S106).

[0097] Figure 9 is an example diagram for selecting the distance between the poles in the shape design method of the resonance pad of the wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0098] Reference Figure 9 , in the case where the pole area is constant, this case represents the change in transmission power according to the distance between the poles. There may be a trend that as the distance between the poles is smaller, the leakage magnetic resistance R lk increases, the coupling coefficient k decreases, and the transmission power decreases. However, since the distance between the poles cannot be unconditionally selected to be large, the shape of the resonance pad can be designed by FEM simulation.

[0099] Thereafter, the transmitting pad 10 can be asymmetrically arranged in the vehicle width direction (operation S107).

[0100] Reference Figure 3 and Figure 4 , due to the reduction of the magnetic resistance, the leakage magnetic flux on the transmitter 100 side can increase. The inductance L1 and leakage inductance on the transmitter 100 side can increase.

[0101] The magnetic resistance Rm between the transmitter 100 side and the receiver 200 side can be almost constant. The mutual magnetic flux and can be maintained and the maximum transmission power selected in the above design can be enabled to be maintained.

[0102] Thereafter, verification can be performed by FEM simulation (operation S108). In the verification by FEM simulation (operation S108), it can be verified whether the target maximum transmission power is satisfied under the misalignment condition of the transmitting pad 10 and the receiving pad 20 in the vehicle width direction.

[0103] Figures 10 to 12It is an example diagram, and each example diagram can be used to verify by simulation in the shape design method of the resonance pad in the wireless charging system for electric vehicles according to the exemplary embodiments of the present disclosure.

[0104] The first magnet 110, the first coil 130, and the second magnet 120 can be arranged as the transmitting pad 10. The second coil 220 can be arranged to face the second magnet 120. The third magnet 210 can be arranged as the receiving pad 20 on the second coil 220. The transmitting pad 10 and the receiving pad 20 can be specified in an asymmetric form.

[0105] In addition, in the transmitter 100, an asymmetric design of the transmitting pad 10 in the Y-axis direction can be performed according to the misalignment condition in the vehicle width (Y-axis) direction.

[0106] As an example, in Figure 10 and Figure 11 under the Y-axis misalignment condition + / −100 mm shown, the transmitter 100 can be increased by 200 mm in the Y-axis direction. That is, the pole area of the transmitter 100 can be set to 25 mm in the X-axis direction and 300 mm in the Y-axis direction, and the pole area on the receiver 200 side can be set to 25 mm in the X-axis direction and 100 mm in the Y-axis direction. In addition, in the Z-axis direction, the pole area of the transmitter 100 can be set to 75 mm, and the pole area of the receiver 200 can be set to 50 mm.

[0107] The asymmetric misalignment condition, the inductance L P and L S due to Y-axis misalignment, and the mutual inductance M can be derived.

[0108] In Figure 12 shown worst misalignment condition, it can be verified whether the maximum transmission power is satisfied. In Figure 12 , under the conditions that the pole area of the transmitter 100 is + / −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 verified whether the target maximum transmission power (for example, 10 kVA) can be achieved.

[0109] Figure 13 It is a diagram showing the maximum transmission power in the case of misalignment in the shape design method of the resonance pad in the wireless charging system for electric vehicles according to the exemplary embodiments of the present disclosure.

[0110] As Figure 13As shown, it can be seen that when a 10 mm gap d is formed between the transmitting pad 10 and the receiving pad 20, depending on the degree of misalignment, the target maximum transmission power (e.g., 10 kVA) can be achieved with adjustments up to 12.5 mm in the X-axis direction and up to 50 mm in the Y-axis direction (e.g., misalignment = 1) and up to + / - 25 mm in the X-axis direction and + / - 100 mm in the Y-axis direction (e.g., misalignment = 2) relative to the maximum transmission power.

[0111] Thus, for example, with respect to the maximum design pad specifications, the area of the receiver 200 can be set to 2500 mm 2 , and the receiver 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 transmitter 100 can be set to 2500 mm 2 , and the transmitter 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.

[0112] Figure 14 FIG. is a diagram showing a case where only an asymmetric design is applied without using an actuator in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure, and Figure 15 FIG. is a diagram showing a case where an asymmetric design is applied by using an actuator in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0113] As Figure 14 shown, when only an asymmetric design is applied without the actuator 40, the core size L in the Y-axis direction core can increase. However, as Figure 15 shown, when Y-axis direction control can be performed by using the actuator 40, the core size in the Y-axis direction can be reduced, and thus, the asymmetry of the transmitter 100 can be alleviated, and the volume can be reduced and the cost can be lowered.

[0114] Figure 16 FIG. is a flowchart showing a wireless charging process in a case where a Y-axis position sensor is used in a wireless charging system for an electric vehicle according to an exemplary embodiment of the present disclosure.

[0115] During the communication standby period (operation S201) of the transmitter 100 and the receiver 200, when it is confirmed whether the communication connection is completed (operation S202), the pad position sensor can be activated, and the vehicle 5 can wait to enter the charging system (operation S203).

[0116] Thereafter, vehicle 5 can enter, and it can be confirmed whether vehicle 5 has entered within the range of the pad position sensor (operation S204).

[0117] When it is confirmed that vehicle 5 has entered within the range of the pad position sensor, the horizontal axis position Y of the receiving pad 20 can be calculated va and the horizontal axis movement distance Y of the transmitter 100 ga (operation S205), and it can be confirmed whether the transmitter 100 is movable (operation S206). When the absolute value of the horizontal axis movement distance Y of the transmitter 100 ga is less than the maximum horizontal axis movement distance Y of the transmitter 100 ga,max the Y-axis direction movement and charging of the transmitter 100 can be started (operation S207).

[0118] By using the Y-axis position sensor, similar to the actuator 40, asymmetry reduction of the transmitter 100 and volume reduction and cost reduction according to the reduction of the core size in the Y-axis direction can be achieved.

[0119] As described above, according to an exemplary embodiment of the present disclosure, the transmitter can be configured with a bipolar pad, and by considering the lateral allowable deviation between the transmitting pad and the receiving pad for wireless charging of an electric vehicle, the size of the lateral core of the transmitting pad can be configured asymmetrically (or wider than the receiving pad) with respect to the receiving pad. Therefore, for the position alignment of the transmitting pad and the receiving pad, the need for lateral movement of the vehicle can be eliminated or minimized, thereby potentially simplifying the charging system.

[0120] By using the embodiment, the stress felt by the customer for the position alignment of the transmitting pad and the receiving pad can be minimized, and a system design that is robust to misalignment can be achieved.

[0121] By using the embodiment, by keeping the gap between the transmitting pad and the receiving pad within a short distance, the volume of the transmitting pad and the receiving pad can be reduced, and the power transmission capacity can be increased and the charging efficiency can be improved.

[0122] By using the embodiment, an actuator for reducing the gap between the transmitting pad and the receiving pad can be provided to reduce the installation cost of the transmitter or the receiver, and the complexity of the actuator for position control can be minimized by the asymmetric design of the transmitting pad.

[0123] By using the embodiment, by minimizing the variable change of the circuit according to the misalignment situation, the use of variable elements in the receiver-side compensation circuit can be minimized to simplify the receiver structure, reduce the cost, and reduce the volume of the receiver.

[0124] Although the present disclosure has been described in connection with embodiments that are presently considered to be practical exemplary embodiments, it should 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. A wireless charging system for an electric vehicle, comprising: a transmitter comprising a transmitting pad mounted on an exterior of the vehicle, wherein the transmitter is configured to generate an electromagnetic field by receiving energy; and A receiver including a receiving pad installed inside the vehicle, wherein the receiving pad is disposed and configured to face the transmitting pad, wherein the receiver is configured to induce a voltage through the electromagnetic field generated by the transmitting pad and charge a battery of the vehicle, wherein the transmitting pad is configured to transmit a specified output even if the transmitting pad is formed asymmetrically with respect to the receiving pad in a width direction of the vehicle.

2. The system according to claim 1, wherein: The receiver includes a power conversion circuit configured to convert power received through the receiving pad into a DC voltage.

3. The system according to claim 1, further comprising: An actuator is installed inside the vehicle, wherein the actuator is configured to adjust a vertical distance between the sending pad and the receiving pad.

4. The system according to claim 3, wherein: The actuator is configured so that the vertical distance between the sending pad and the receiving pad can be adjusted to a spacing of 100 mm or less.

5. The system according to claim 1, further comprising: A parking block is mounted separately from the vehicle, wherein the parking block is configured to adjust a longitudinal alignment of the vehicle.

6. The system according to claim 1, wherein: The transmitting pad comprises a dipole resonant pad structure, and wherein the dipole resonant pad structure comprises: a first magnet formed to protrude in a height direction of the vehicle, wherein a first coil is wound around the first magnet; and A pair of second magnets are coupled to ends of the first magnet in a form of further protruding in the height direction.

7. The system according to claim 6, wherein: The receiving pad includes a third magnet, wherein the third magnet is configured to be disposed opposite to the first magnet and to protrude toward the first magnet, and wherein a second coil is wound around the third magnet.

8. The system according to claim 7, wherein: The dipole resonant pad structure is configured to meet a specified transmission power for short-range wireless charging.

9. The system of claim 1, further comprising: A pad position sensor is configured to sense relative positions of the transmitting pad and the receiving pad in a width direction of the vehicle.

10. A method for designing the shape of a resonance pad for a wireless charging system of an electric vehicle, comprising the following steps: Select the shape of the sending and receiving pads; analyzing a magnetic circuit including the transmitting pad and the receiving pad; selecting a maximum transmission power based on a maximum vertical distance between the transmit pad and the receive pad and based on a horizontal misalignment between the transmit pad and the receive pad; Choose the magnetomotive force that takes into account the losses per unit volume; Calculate polar area; Select a first distance between poles; disposing the transmitting pad asymmetrically in a vehicle width direction relative to the receiving pad; and Verify through simulation.

11. The method according to claim 10, wherein: Selecting the shapes of the transmitting pad and the receiving pad includes selecting the shapes of the transmitting pad and the receiving pad such that the shape of the transmitting pad is asymmetric relative to the receiving pad, wherein the transmitting pad has a dipole resonant pad structure.

12. The method according to claim 10, wherein: The analysis of the magnetic circuit is performed by sensing the magnetic equivalent circuit of the transmitting pad and the receiving pad by an inductive power transfer rule equation.

13. The method according to claim 10, wherein: Selecting the maximum transmission power includes modeling the maximum transmission power using Equation 1: Formula 1: V OC I SC = ω(M 2 / L S )I P 2 = ωL P k 2 I P 2 , Among them, V OC is the voltage, I SC is the current, ω is the frequency of the alternating current, M is the mutual inductance, L P is the self-inductance of the primary coil associated with the transmitting pad, L S is the self-inductance of the secondary coil associated with the receiving pad, I P is the current in the primary coil, and k is the coupling coefficient between the primary coil and the secondary coil.

14. The method according to claim 10, wherein: When choosing to consider the magnetomotive force per unit volume loss, the magnetomotive force is modeled as Formula 2: Formula 2: N1I P =kl g B max / μ0, Where N1 is the number of turns of the primary coil associated with the transmitting pad, I P is the current in the primary coil, I g is a given vertical distance between the transmitting pad and the receiving pad, k is the minimum bonding factor for the misalignment case in the given vertical distance between the transmitting pad and the receiving pad, B max is the maximum magnetic flux density representing the peak magnetic field strength in the air gap between the transmitting pad and the receiving pad, and μ0 is a constant representing the magnetic permeability of free space at the air gap.

15. The method according to claim 10, wherein: When calculating the polar area, the polar area is modeled as Formula 3: Formula 3: A = 2l g P uc / kω(N1I P )2μ0, Where A is the cross-sectional area through which the magnetic flux passes, l g is a given vertical distance between the transmitting pad and the receiving pad, k is the minimum bonding coefficient for the misalignment case in the given vertical distance between the transmitting pad and the receiving pad, P uc is the decoupled power representing the power transmitted when the transmitting pad and the receiving pad 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 the primary coil associated with the transmitting pad, and I P is the current in the primary coil, and μ0 is a constant representing the magnetic permeability of free space at the air gap between the transmitting pad and the receiving pad.

16. The method according to claim 10, wherein: When selecting the first distance between the poles, the first distance between the poles is set by finite element method simulation.

17. The method according to claim 10, wherein: Disposing the transmitting pad asymmetrically in the vehicle width direction includes disposing the second magnet on one side to be 200 mm long in the vehicle width direction.

18. The method according to claim 10, wherein: Verifying through the simulation includes verifying whether a target maximum transmission power is satisfied under a misalignment condition of the transmitting pad and the receiving pad in the vehicle width direction.

19. A wireless charging system for a vehicle, comprising: a transmitter including a transmitting pad configured to be mounted separately from the vehicle, wherein the transmitter is configured to generate an electromagnetic field by receiving energy; and A receiver comprising a receiving pad mounted on the vehicle, wherein the receiving pad is configured to face the transmitting pad when the vehicle is located above the transmitter, wherein the receiver is configured to induce a voltage through the electromagnetic field generated by the transmitting pad and charge a battery of the vehicle, wherein the transmitting pad is wider than the receiving pad in a vehicle width direction.

20. The system of claim 19, wherein: The transmitting pad comprises a dipole resonant pad structure, and wherein the dipole resonant pad structure comprises: A U-shaped first magnet is formed to protrude in the height direction of the vehicle, wherein a first coil is wound around the first magnet; and a pair of bar-shaped second magnets coupled to ends of the first magnet in a form further protruding in the height direction, wherein the second magnets have a first width in the vehicle width direction; and wherein the receiving pad comprises a U-shaped third magnet, wherein the third magnet is configured to be disposed opposite to the first magnet and to protrude toward the first magnet when the receiver is located above the transmitter, wherein the third magnet is wound with a second coil, and wherein a measured distance across the protruding end of the third magnet in the vehicle width direction has a second width, and wherein the first width is greater than the second width.

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