Wireless power transmission device and wireless power transmission method thereof

Abstract

A wireless power transmission device according to an embodiment of the present invention comprises: a control unit; a power conversion unit that converts power received from a power supply device; and a transmission coil unit to which a current output from the power conversion unit is applied. The transmission coil unit includes a first transmission coil, a second transmission coil, and a third transmission coil. The power conversion unit includes: a power factor compensation circuit unit that outputs a DC voltage from the power received from the power supply device; and an inverter unit that outputs, as an AC voltage, a DC voltage received from the power factor compensation circuit unit. The inverter unit outputs a first AC voltage, a second AC voltage, and a third AC voltage, wherein at least two among the amplitude of the first AC voltage, the amplitude of the second AC voltage, and the amplitude of the third AC voltage are different from each other, and the duty ratio of the first AC voltage, the duty ratio of the second AC voltage, and the duty ratio of the third AC voltage are the same as each other.

Description

Wireless power transmission device and wireless power transmission method thereof

[0001] The present invention relates to a wireless power transmission device for an electric vehicle and a wireless power transmission method thereof.

[0002] A wireless charging system for an electric vehicle includes a power supply unit, a ground assembly (GA), and a vehicle assembly (VA). In the case of static wireless power transfer, the ground assembly is placed on the floor of a parking lot, and the electric vehicle can be charged while parked via the vehicle assembly. In the case of dynamic wireless power transfer, the ground assembly is placed on the road, and the electric vehicle can be charged while driving via the vehicle assembly.

[0003] Power can be wirelessly transferred from the ground assembly to the vehicle assembly via magnetic induction or magnetic resonance between a transmitting coil in the ground assembly and a receiving coil in the vehicle assembly.

[0004] To reduce charging times for electric vehicles, a large-capacity wireless charging system is needed. However, when large amounts of power are transferred in a wireless charging system comprising a single transmitting coil and a single receiving coil, high electromagnetic waves can be generated due to leakage magnetic flux.

[0005] Meanwhile, in a wireless charging system for an electric vehicle, the efficiency of wireless charging may vary depending on the degree of alignment between the transmitting coil of the ground assembly and the receiving coil of the vehicle assembly. If wireless charging is initiated without alignment between the transmitting coil of the ground assembly and the receiving coil of the vehicle assembly, an overcurrent may occur on the transmitting coil side or the transmitting coil side may overheat.

[0006] The technical problem to be solved by the present invention is to provide a wireless power transmission device and a wireless power transmission method thereof in a wireless charging system for an electric vehicle.

[0007] Another technical problem to be achieved by the present invention is to provide a wireless power transmission device and a wireless power transmission method thereof with limited leakage magnetic flux and electromagnetic wave generation in a wireless charging system for an electric vehicle.

[0008] Another technical problem to be achieved by the present invention is to provide a wireless power transmission device and a wireless power transmission method thereof with improved power transmission efficiency between a transmitting coil and a receiving coil in a wireless charging system for an electric vehicle.

[0009] A wireless power transmission device according to one embodiment of the present invention includes a control unit, a power conversion unit that converts power received from a power supply device, and a transmission coil unit to which a current output from the power conversion unit is applied, wherein the transmission coil unit includes a first transmission coil, a second transmission coil, and a third transmission coil, and the current output from the power conversion unit includes a first current applied to the first transmission coil, a second current applied to the second transmission coil, and a third current applied to the third transmission coil, and at least two of an amplitude of the first current, an amplitude of the second current, and an amplitude of the third current are different from each other, or at least two of a phase difference between the first current and the second current, a phase difference between the second current and the third current, and a phase difference between the third current and the first current are different from each other, and at least one of an amplitude and a phase of the first current, at least one of an amplitude and a phase of the second current, and at least one of an amplitude and a phase of the third current are controlled by the control unit.

[0010] The control unit can control the power conversion unit based on alignment information between the transmitting coil unit and the receiving coil unit included in the wireless power receiving device.

[0011] The power conversion unit includes a power factor correction circuit unit that outputs a DC voltage from power received from the power supply device, an inverter unit that outputs the DC voltage received from the power factor correction circuit unit as an AC voltage, and an impedance matching unit arranged between the inverter unit and the transmitting coil unit, and the control unit can control at least one of the power factor correction circuit unit, the inverter unit, and the impedance matching unit based on the alignment information.

[0012] The inverter unit outputs a phase-shifted first voltage, a second voltage, and a third voltage, and at least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current can be controlled by the first voltage, the second voltage, and the third voltage.

[0013] At least two of the duty ratio of the first voltage, the duty ratio of the second voltage, and the duty ratio of the third voltage may be different from each other.

[0014] The inverter unit may include a first full-bridge inverter outputting the first voltage, a second full-bridge inverter outputting the second voltage, and a third full-bridge inverter outputting the third voltage.

[0015] It may further include a sensor unit that detects the alignment information between the transmitting coil unit and the receiving coil unit.

[0016] The sensor unit may include a plurality of position sensors arranged around the first transmitting coil, the second transmitting coil, and the third transmitting coil.

[0017] A wireless power transmission method of a wireless power transmission device according to one embodiment of the present invention includes a power conversion step of converting power received from a power supply device, and a current application step of applying a current output in the power conversion step to a first transmission coil, a second transmission coil, and a third transmission coil, wherein the current output in the power conversion step includes a first current applied to the first transmission coil, a second current applied to the second transmission coil, and a third current applied to the third transmission coil, and in the power conversion step, at least two of an amplitude of the first current, an amplitude of the second current, and an amplitude of the third current are controlled to be different from each other, or at least two of a phase difference between the first current and the second current, a phase difference between the second current and the third current, and a phase difference between the third current and the first current are controlled to be different from each other.

[0018] The method further includes a step of obtaining alignment information between the first transmitting coil, the second transmitting coil, and the third transmitting coil and the first receiving coil, the second receiving coil, and the third receiving coil included in the wireless power receiving device, wherein at least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current can be controlled based on the alignment information.

[0019] In the power conversion step, a first voltage, a second voltage, and a third voltage that are phase-shifted are generated from the power received from the power supply device, and at least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current can be controlled by the first voltage, the second voltage, and the third voltage.

[0020] According to another embodiment of the present invention, a wireless power transmission device includes a control unit, a power conversion unit that converts power received from a power supply device, and a transmission coil unit to which a current output from the power conversion unit is applied, wherein the transmission coil unit includes a first transmission coil, a second transmission coil, and a third transmission coil, and the power conversion unit includes a power factor correction circuit unit that outputs a DC voltage from the power received from the power supply device, and an inverter unit that outputs the DC voltage received from the power factor correction circuit unit as an AC voltage, and the inverter unit outputs a first AC voltage, a second AC voltage, and a third AC voltage, and at least two of an amplitude of the first AC voltage, an amplitude of the second AC voltage, and an amplitude of the third AC voltage are different from each other, and a duty ratio of the first AC voltage, a duty ratio of the second AC voltage, and a duty ratio of the third AC voltage are equal to each other.

[0021] The power factor correction circuit unit includes a first power factor correction circuit, a second power factor correction circuit, and a third power factor correction circuit, and the inverter unit includes a first inverter into which a first DC voltage output from the first power factor correction circuit is input, a second inverter into which a second DC voltage output from the second power factor correction circuit is input, and a third inverter into which a third DC voltage output from the third power factor correction circuit is input, wherein the first AC voltage can be output from the first inverter, the second AC voltage can be output from the second inverter, and the third AC voltage can be output from the third inverter.

[0022] The first power factor compensation circuit, the second power factor compensation circuit, and the third power factor compensation circuit can be controlled by the control unit based on alignment information between the transmitting coil unit and the receiving coil unit included in the wireless power receiving device.

[0023] The input of the first power factor correction circuit is the first phase power received from the power supply device, the input of the second power factor correction circuit is the second phase power received from the power supply device, and the input of the third power factor correction circuit is the third phase power received from the power supply device, and at least one of the first power factor correction circuit, the second power factor correction circuit, and the third power factor correction circuit can be connected to a neutral point.

[0024] The current output from the power conversion unit includes a first current applied to the first transmitting coil, a second current applied to the second transmitting coil, and a third current applied to the third transmitting coil, and at least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current can be controlled by the first AC voltage, the second AC voltage, and the third AC voltage.

[0025] At least two of the amplitude of the first current, the amplitude of the second current, and the amplitude of the third current may be different from each other, or at least two of the phase difference between the first current and the second current, the phase difference between the second current and the third current, and the phase difference between the third current and the first current may be different from each other.

[0026] The first inverter, the second inverter, and the third inverter may each be a full-bridge inverter.

[0027] The power conversion unit may further include an impedance matching unit disposed between the inverter unit and the transmitting coil unit.

[0028] A wireless power transmission device according to another embodiment of the present invention includes a control unit, a power conversion unit that converts power received from a power supply device, and a transmission coil unit to which a current output from the power conversion unit is applied, wherein the transmission coil unit includes a first transmission coil, a second transmission coil, and a third transmission coil, and the power conversion unit includes a power factor correction circuit unit that outputs a DC voltage from the power received from the power supply device, and an inverter unit that outputs the DC voltage received from the power factor correction circuit unit as an AC voltage, and the power factor correction circuit unit includes a first power factor correction circuit that outputs a first DC voltage, a second power factor correction circuit that outputs a second DC voltage, and a third power factor correction circuit that outputs a third DC voltage, and the inverter unit includes a first inverter that outputs the first DC voltage as a first AC voltage, a second inverter that outputs the second DC voltage as a second AC voltage, and a third inverter that outputs the third DC voltage as a third AC voltage, and the first power factor correction circuit, the second power factor correction circuit, and the third The power factor compensation circuit is controlled by the control unit based on alignment information between the transmitting coil unit and the receiving coil unit included in the wireless power receiving device.

[0029] A wireless power transmission method of a wireless power transmission device according to another embodiment of the present invention includes a power conversion step of converting power received from a power supply device, and a current application step of applying a current output from the power conversion step to a first transmission coil, a second transmission coil, and a third transmission coil, wherein the power conversion step includes a step of outputting a first DC voltage, a second DC voltage, and a third DC voltage from the power received from the power supply device, and a step of outputting the first DC voltage, the second DC voltage, and the third DC voltage as a first AC voltage, a second AC voltage, and a third AC voltage, wherein in the power conversion step, at least two of the amplitude of the first AC voltage, the amplitude of the second AC voltage, and the amplitude of the third AC voltage are different from each other, and the duty ratio of the first AC voltage, the duty ratio of the second AC voltage, and the duty ratio of the third AC voltage are controlled to be equal to each other.

[0030] The first DC voltage, the second DC voltage, and the third DC voltage can be controlled based on alignment information between the first transmitting coil, the second transmitting coil, and the third transmitting coil and the first receiving coil, the second receiving coil, and the third receiving coil of the wireless power receiving device.

[0031] A wireless power transmission method of a wireless power transmission device according to another embodiment of the present invention includes a position detection step of obtaining alignment information between a transmitting coil unit of the wireless power transmission device and a receiving coil unit of a wireless power reception device, and a power transmission step of transmitting power to the receiving coil unit through the transmitting coil unit based on the alignment information obtained in the position detection step, wherein the transmitting coil unit includes a first transmitting coil, a second transmitting coil, and a third transmitting coil, and the receiving coil unit includes a first receiving coil, a second receiving coil, and a third receiving coil, and in the position detection step, a position detection current is applied to the first transmitting coil, the position detection current is applied to the second transmitting coil, the position detection current is applied to the third transmitting coil, and the position detection current is sequentially applied to the first transmitting coil, the second transmitting coil, and the third transmitting coil so as not to overlap each other.

[0032] In the power transmission step, a first current is applied to the first transmitting coil, a second current is applied to the second transmitting coil, a third current is applied to the third transmitting coil, and the first current, the second current, and the third current can be applied simultaneously to the first transmitting coil, the second transmitting coil, and the third transmitting coil.

[0033] The amplitude of the current for position detection may be smaller than the amplitude of the first current, the amplitude of the second current, and the amplitude of the third current.

[0034] In the position detection step, the amplitudes of the position detection currents applied to the first transmission coil, the second transmission coil, and the third transmission coil are the same, and in the power transmission step, at least two of the amplitudes of the first current, the second current, and the third current may be different from each other.

[0035] At least two of the phase difference between the first current and the second current, the phase difference between the second current and the third current, and the phase difference between the third current and the first current may be different from each other.

[0036] At least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current can be controlled based on the alignment information acquired in the position detection step.

[0037] A standby step may further be included between the position detection step and the power transmission step.

[0038] A wireless charging method of a wireless charging system according to another embodiment of the present invention includes a position detection step of obtaining alignment information between a transmitting coil unit of a wireless power transmitting device and a receiving coil unit of a wireless power receiving device, and a power transmission step of transmitting power to a receiving coil unit through the transmitting coil unit based on the alignment information obtained in the position detection step, wherein the transmitting coil unit includes a first transmitting coil, a second transmitting coil, and a third transmitting coil, and the receiving coil unit includes a first receiving coil, a second receiving coil, and a third receiving coil, and the position detection step includes a step of sequentially applying a position detection current to the first transmitting coil, the second transmitting coil, and the third transmitting coil so as not to overlap each other, and a step of detecting a voltage induced in the first receiving coil, the second receiving coil, and the third receiving coil by the position detection current.

[0039] The position detection step may further include a step of calculating mutual inductance between the transmitting coil unit and the receiving coil unit based on a voltage induced in the first to third receiving coils when the position detection current is applied to the first transmitting coil, a voltage induced in the first to third receiving coils when the position detection current is applied to the second transmitting coil, and a voltage induced in the first to third receiving coils when the position detection current is applied to the third transmitting coil, and a step of detecting a relative position between the transmitting coil unit and the receiving coil unit based on the mutual inductance.

[0040] The above mutual inductance can be calculated as a 3*3 matrix between the first to third transmitting coils and the first to third receiving coils.

[0041] In the power transmission step, a first current is applied to the first transmitting coil, a second current is applied to the second transmitting coil, a third current is applied to the third transmitting coil, and the first current, the second current, and the third current can be applied simultaneously to the first transmitting coil, the second transmitting coil, and the third transmitting coil.

[0042] The amplitude of the current for position detection may be smaller than the amplitude of the first current, the amplitude of the second current, and the amplitude of the third current.

[0043] According to an embodiment of the present invention, leakage flux and electromagnetic wave generation in a wireless charging system for an electric vehicle can be limited. Furthermore, according to an embodiment of the present invention, power transfer efficiency between a transmitting coil and a receiving coil in a wireless charging system for an electric vehicle can be improved. Furthermore, according to an embodiment of the present invention, the relative position between a transmitting coil and a receiving coil in a wireless charging system for an electric vehicle can be efficiently detected. Furthermore, according to an embodiment of the present invention, a high-power wireless charging system of 22 kW or more with limited leakage flux and high charging efficiency can be obtained. Furthermore, according to an embodiment of the present invention, in a wireless charging system for an electric vehicle, high power transfer efficiency between a transmitting coil and a receiving coil can be obtained without overheating of the transmitting coil side even when the transmitting coil and the receiving coil are not precisely aligned.

[0044] FIG. 1 is a block diagram of an electric vehicle and a wireless charging system according to one embodiment of the present invention.

[0045] FIG. 2 is a block diagram of a wireless charging system according to one embodiment of the present invention.

[0046] FIG. 3 is a block diagram of a power supply device included in a wireless charging system according to one embodiment of the present invention.

[0047] FIG. 4 is a schematic diagram of a wireless charging system according to one embodiment of the present invention.

[0048] FIG. 5 is a more detailed schematic diagram of a wireless charging system according to one embodiment of the present invention.

[0049] FIG. 6 is a flowchart of a wireless power transmission method of a wireless power transmission device included in a wireless charging system according to one embodiment of the present invention.

[0050] FIG. 7 is a circuit diagram of a wireless charging system according to one embodiment of the present invention.

[0051] Fig. 8 is a voltage waveform output from the inverter unit according to the circuit diagram of Fig. 7.

[0052] Fig. 9 is a current waveform applied to the transmitting coil section by the circuit diagram of Fig. 7.

[0053] FIG. 10 is a circuit diagram of a wireless charging system according to another embodiment of the present invention.

[0054] Fig. 11 is a voltage waveform output from the inverter unit by the circuit diagram of Fig. 10.

[0055] Fig. 12 is a current waveform applied to the transmitting coil section by the circuit diagram of Fig. 10.

[0056] Fig. 13 is a circuit diagram of a wireless charging system according to another embodiment of the present invention.

[0057] Fig. 14 is a flowchart of a wireless power transmission method according to the circuit diagram of Fig. 13.

[0058] Fig. 15 is a voltage waveform output from the inverter unit by the circuit diagram of Fig. 13.

[0059] Fig. 16 is a current waveform applied to the transmitting coil section by the circuit diagram of Fig. 13.

[0060] Fig. 17 shows the voltage waveform and inverter current waveform output from the inverter unit by the circuit diagram of Fig. 13.

[0061] Fig. 18 is a flowchart of a wireless charging method of a wireless charging system according to one embodiment of the present invention.

[0062] FIG. 19 is an example of obtaining alignment information between a transmitting coil unit and a receiving coil unit according to one embodiment of the present invention.

[0063] FIG. 20 is a flowchart of a wireless charging method of a wireless charging system according to another embodiment of the present invention.

[0064] FIG. 21 is an example of obtaining alignment information between a transmitting coil unit and a receiving coil unit according to another embodiment of the present invention.

[0065] FIG. 22 is an example of a state in which a transmitting coil unit and a receiving coil unit included in a wireless charging system according to one embodiment of the present invention are not aligned.

[0066] Fig. 23 is a detailed flowchart of the wireless charging method described through Figs. 20 and 21.

[0067] Figure 24 shows the current applied to the transmitting coil section step by step in Figure 23.

[0068] Figure 25 shows the voltage induced in the receiving coil section step by step in Figure 23.

[0069] Fig. 26 is a waveform of a current applied to a transmitting coil unit in a position detection step of a wireless charging method according to an embodiment of the present invention.

[0070] Fig. 27 is a waveform of a voltage induced in a receiving coil section when the current of Fig. 26 is applied to the transmitting coil section while the transmitting coil section and the receiving coil section are aligned.

[0071] Fig. 28 is a waveform of a voltage induced in a receiving coil section when the current of Fig. 26 is applied to the transmitting coil section in a state where the transmitting coil section and the receiving coil section are not aligned.

[0072] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0073] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0074] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0075] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0076] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0077] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0078] These terms are intended only to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

[0079] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0080] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0081] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or corresponding components are given the same reference numbers, and redundant descriptions thereof will be omitted.

[0082] FIG. 1 is a block diagram of an electric vehicle and a wireless charging system according to one embodiment of the present invention, FIG. 2 is a block diagram of a wireless charging system according to one embodiment of the present invention, FIG. 3 is a block diagram of a power supply device included in a wireless charging system according to one embodiment of the present invention, FIG. 4 is a schematic diagram of a wireless charging system according to one embodiment of the present invention, FIG. 5 is a more specific schematic diagram of a wireless charging system according to one embodiment of the present invention, and FIG. 6 is a flowchart of a wireless power transmission method of a wireless power transmission device included in a wireless charging system according to one embodiment of the present invention.

[0083] Referring to FIG. 1, an electric vehicle (EV) 10 can be charged by a wireless charging system (20). In this specification, an electric vehicle (10) means a vehicle propelled by an electric motor that draws current from a rechargeable storage battery or other portable energy storage device.

[0084] According to an embodiment of the present invention, the electric vehicle (10) may be a vehicle that can be recharged through a wireless charging method without using a physical plug and socket.

[0085] Referring to FIGS. 2 to 5, the wireless charging system (20) includes a wireless power transmission device (100), a wireless power reception device (200), and a power supply device (300).

[0086] The wireless power transmission device (100) includes a control unit (110), a power conversion unit (120), and a transmission coil unit (130), and the wireless power reception device (200) includes a control unit (210), a power conversion unit (220), and a reception coil unit (230).

[0087] The transmitting coil unit (130) of the wireless power transmitting device (100) may be placed on the floor of a parking lot or on a road, or at least partially buried, and the receiving coil unit (230) of the wireless power receiving device (200) may be mounted on an electric vehicle (10). The receiving coil unit (230) may be mounted on the lower part of the electric vehicle (10) and aligned to face the transmitting coil unit (130) buried in the floor of a parking lot or on a road, and a current applied to the transmitting coil unit (130) may generate an induced voltage in the receiving coil unit (230). Accordingly, the transmitting coil unit (130) or at least a portion of the configuration of the wireless power transmitting device (100) including the transmitting coil unit (130) may be referred to as a ground assembly (GA). The receiving coil unit (230) or at least a portion of the configuration of the wireless power receiving device (200) including the receiving coil unit (230) may be referred to as a vehicle assembly (VA).

[0088] In the case of a static wireless power transfer method, a transmitting coil unit (130) is placed on the floor of a parking lot, and the transmitting coil unit (130) can be aligned with a receiving coil unit (230) mounted on a parked electric vehicle (10).

[0089] The power supply device (300) controls the wireless power transmission device (100) and / or the wireless power reception device (200) and supplies power to the wireless power transmission device (100). To this end, the power supply device (300) communicates with the wireless power transmission device (100) and / or the wireless power reception device (200) and can transmit a control signal to each of the wireless power transmission device (100) and the wireless power reception device (200). The power supply device (300) may be an electric vehicle supply equipment (EVSE) or a part of the EVSE, and may be used interchangeably with a grid, a power source, a system, etc.

[0090] The power supply device (300) includes a control unit (310), a communication unit (320), and a power supply unit (330). The control unit (310) can control at least one of the control unit (110), the power conversion unit (120), and the transmission coil unit (130) of the wireless power transmission device (100). Alternatively, at least a portion of the control unit (310) of the power supply device (300) and the control unit (110) of the wireless power transmission device (100) may be integrated. The communication unit (320) communicates with the electric vehicle (10) or an electric vehicle communication controller (EVCC) mounted on the electric vehicle (10), and also communicates with the wireless power transmission device (100). The power supply unit (330) supplies power to the wireless power reception device (200) mounted on the electric vehicle (10) through the wireless power transmission device (100). The control unit (310) and the communication unit (320) of the power supply device (300) may be a SECC (supply equipment communication controller). Alternatively, the control unit (310) and the communication unit (320) of the power supply device (300) and a part of the control unit (110) of the wireless power transmission device (100) may be SECCs. The power supply device (300) may be referred to as a wireless charging device or EVSE, and the control unit (310) and the communication unit (320) of the power supply device (300) may be referred to as a wireless charging control device.

[0091] Although not shown, the wireless power transmitter (100) and the wireless power receiver (200) may each further include a communication unit.

[0092] When the receiving coil unit (230) is aligned on the transmitting coil unit (130), signal exchange for connection establishment between the communication unit of the wireless power transmitting device (100) and the communication unit of the wireless power receiving device (200) can occur. For example, the communication unit of the wireless power transmitting device (100) periodically transmits a ping signal, and the communication unit of the wireless power receiving device (200) that receives the ping signal can establish a connection through signal exchange with the communication unit of the wireless power transmitting device (100).

[0093] The communication unit of the wireless power transmission device (100) and the communication unit of the wireless power reception device (200) may communicate with the power supply device (300). For example, the communication unit of the wireless power transmission device (100) may transmit connection information with the wireless power reception device (200) to the power supply device (300), and the power supply device (300) may transmit a control signal for wireless power transmission to the communication unit of the wireless power transmission device (100). The communication unit of the wireless power transmission device (100) drives the control unit (110) based on the control signal received from the power supply device (300), and the transmission coil unit (130) may be controlled according to the driving of the control unit (110). The communication unit of the wireless power transmission device (100) may be integrated with the control unit (110) of the wireless power transmission device (100) or may be integrated with the communication unit (320) of the power supply device (300).

[0094] In addition, the communication unit of the wireless power receiving device (200) can transmit vehicle information to the power supply device (300), and the power supply device (300) can transmit a control signal for wireless power reception to the communication unit of the wireless power receiving device (200). The communication unit of the wireless power receiving device (110) drives the control unit (210) based on the control signal received from the power supply device (300), and the receiving coil unit (230) can be controlled according to the driving of the control unit (210). At least some of the communication unit and the control unit (210) of the wireless power receiving device (200) may be a part of an EVCC mounted on an electric vehicle (10).

[0095] In wireless charging technology for electric vehicles, there is a need for high-power wireless charging systems to reduce charging times. Attempts are also being made to address the potential impact on the human body caused by electromagnetic waves generated during high-power transmission. If the ground assembly and vehicle assembly each have a single transmitting coil and a single receiving coil, the leakage flux can be very large during high-power transmission.

[0096] According to an embodiment of the present invention, in order to limit leakage flux during high power transmission, the ground assembly and the vehicle assembly each include a three-phase transmitting coil and a three-phase receiving coil. That is, the transmitting coil unit (130) of the wireless power transmitting device (100) according to the embodiment of the present invention includes a first transmitting coil (131), a second transmitting coil (132), and a third transmitting coil (133), and the receiving coil unit (230) of the wireless power receiving device (200) includes a first receiving coil (231), a second receiving coil (232), and a third receiving coil (233). Accordingly, magnetic asymmetry exists between the transmitting coil unit (130) and the receiving coil unit (230), and the wireless charging efficiency may vary depending on the relative position between the transmitting coil unit (130) and the receiving coil unit (230). When the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) of the transmitting coil unit (130) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) of the receiving coil unit (230) are precisely aligned, the wireless charging efficiency is high. However, when the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) of the transmitting coil unit (130) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) of the receiving coil unit (230) are not precisely aligned, an overcurrent may flow on the transmitting coil unit (130) side or the transmitting coil unit (130) side may overheat, and thus the wireless charging efficiency may be lowered. In order to precisely align the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) of the transmitting coil unit (130) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) of the receiving coil unit (230), the transmitting coil unit (130) side or the receiving coil unit (230) side must move, but precise movement may be difficult.

[0097] According to an embodiment of the present invention, the current applied to the transmitting coil unit (130) is controlled according to alignment information between the transmitting coil unit (130) and the receiving coil unit (230), and accordingly, even when the transmitting coil unit (130) and the receiving coil unit (230) are not precisely aligned, the voltage induced in the receiving coil unit (230) is intended to be maximized.

[0098] To explain more specifically, referring to FIGS. 4 to 6, the wireless power transmission device (100) includes a control unit (110), a power conversion unit (120), and a transmission coil unit (130), and the wireless power reception device (200) includes a control unit (210), a power conversion unit (220), and a reception coil unit (230). As described above, the transmission coil unit (130) includes a first transmission coil (131), a second transmission coil (132), and a third transmission coil (133). The reception coil unit (230) includes a first reception coil (231), a second reception coil (232), and a third reception coil (233). The control unit (110) controls the wireless power transmission device (100), and the control unit (210) controls the wireless power reception device (200).

[0099] A wireless power transmitter (100) receives power from a power supply unit (300). The power supply unit (300) supplies power in three phases. A power conversion unit (120) of the wireless power transmitter (100) converts the power received from the power supply unit (300), and a current output from the power conversion unit (120) is applied to a transmission coil unit (130). A control unit (110) can control a current applied to the transmission coil unit (130) through the power conversion unit (120). The current applied to the transmission coil unit (130) generates an induced voltage in a reception coil unit (230) of a wireless power receiver (200), and the power conversion unit (220) converts the induced voltage received from the reception coil unit (230) and transmits it to a battery. A control unit (210) can control the power conversion unit (220) to satisfy battery output specifications.

[0100] More specifically, the power conversion unit (120) of the wireless power transmitter (100) includes a power factor correction (PFC) circuit unit (121), an inverter unit (122), and an impedance matching unit (123). The power factor correction circuit unit (121) performs AC / DC conversion and outputs power received from the power supply device (300) as a DC voltage. Here, the DC voltage may be referred to as a DC link voltage. The inverter unit (122) performs DC / AC conversion and outputs the DC voltage received from the power factor correction circuit unit (121) as an AC voltage. The inverter unit (122) may be referred to as a high frequency (HF) inverter unit. The impedance matching unit (123) is connected between the inverter unit (122) and the transmitting coil unit (130) to perform impedance matching. The impedance matching unit (123) includes variable passive elements or fixed passive elements and may be referred to as an impedance matching network (IMN).

[0101] The power conversion unit (220) of the wireless power receiving device (200) includes an impedance matching unit (221) and a rectifier (222). The impedance matching unit (221) is placed between the receiving coil unit (230) and the rectifier (222) to perform impedance matching. The impedance matching unit (221) includes a variable passive element or a fixed passive element and may also be referred to as an impedance matching network (IMN). The rectifier (222) converts AC voltage or AC current into DC voltage or DC current to charge the battery.

[0102] According to an embodiment of the present invention, the wireless power transmission device (100) converts power received from the power supply device (300) based on alignment information between the transmitting coil unit (130) and the receiving coil unit (230) and applies current to the transmitting coil unit (130).

[0103] That is, the wireless power transmission device (100) obtains alignment information between the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) included in the transmitting coil unit (130) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) included in the receiving coil unit (230) of the wireless power reception device (200) (S600). To this end, the wireless power transmission device (100) may further include an alignment information obtaining unit (140). Here, the alignment information may be relative position information between the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233). For example, the alignment information between the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) and the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) may vary depending on the distance (R) and the angle (θ). Here, R is the distance between the center of the transmitting coil unit and the center of the receiving coil unit, and θ may be the misalignment angle between the center of the transmitting coil unit and the center of the receiving coil unit. Here, the distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) may be the planar distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230). Here, the planar distance may be the planar distance in which the transmitting coil unit (130) is arranged or the planar distance in which the receiving coil unit (230) is arranged. That is, if the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) overlap in the vertical direction, the distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) can be expressed as 0. Here, the vertical direction may be a direction perpendicular to the plane direction, and may be a direction from the transmitting coil unit (130) toward the receiving coil unit (230). In addition, the angle (θ) may be an angle formed by the transmitting coil unit (130) and the receiving coil unit (230) in the plane direction.A specific method by which the wireless power transmission device (100) obtains alignment information will be described later.

[0104] Next, the power conversion unit (120) of the wireless power transmission device (100) converts the power received from the power supply device (300) based on the alignment information acquired in step S600 (S610), and applies the current output from the power conversion unit (120) to the transmission coil unit (113), i.e., the first transmission coil (131), the second transmission coil (132), and the third transmission coil (133) (S620). To this end, the control unit (110) controls the power conversion unit (120) based on the alignment information acquired in step S600, and the power conversion unit (120) outputs the current to be applied to the transmission coil unit (130) according to the control of the control unit (110).

[0105] The current output from the power conversion unit (120) includes a first current (Ia) applied to the first transmitting coil (131), a second current (Ib) applied to the second transmitting coil (132), and a third current (Ic) applied to the third transmitting coil (133). The first current (Ia), the second current (Ib), and the third current (Ic) are AC currents having their own amplitudes and phases.

[0106] According to an embodiment of the present invention, at least one of the amplitude and phase of the first current (Ia), the amplitude and phase of the second current (Ib), and at least one of the amplitude and phase of the third current (Ic) are controlled by the control unit (110) based on alignment information between the transmitting coil unit (130) and the receiving coil unit (230). At this time, at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from each other, or at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from each other. In the present specification, if at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) are different from each other, or if at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) are different from each other, the first current (Ia), the second current (Ib), and the third current (Ic) may be expressed as being asymmetric. For example, the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may all be different from each other, or one of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from the other two. For example, the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may all be different from each other, or one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from the other two.For example, at least one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may not be 120°.

[0107] In this way, according to an embodiment of the present invention, the first to third currents (Ia, Ib, Ic) applied to the first to third transmission coils (131, 132, 133) of the transmission coil unit (130) are controlled based on the alignment information between the transmission coil unit (130) and the reception coil unit (230). For example, if the transmission coil unit (130) and the reception coil unit (230) are precisely aligned, the first to third currents (Ia, Ib, Ic) applied to the first to third transmission coils (131, 132, 133) of the transmission coil unit (130) can be symmetrical to each other. That is, if the transmitting coil unit (130) and the receiving coil unit (230) are precisely aligned, the first to third currents (Ia, Ib, Ic) applied to the first to third transmitting coils (131, 132, 133) of the transmitting coil unit (130) can all have the same amplitude and a phase difference of 120°. In contrast, if the transmitting coil unit (130) and the receiving coil unit (230) are not precisely aligned, intentional asymmetry is imparted to the first to third currents (Ia, Ib, Ic) applied to the first to third transmitting coils (131, 132, 133) of the transmitting coil unit (130). According to an embodiment of the present invention, asymmetry can be imparted to the first to third currents (Ia, Ib, Ic) so as to minimize loss between the transmitting coil unit (130) and the receiving coil unit (230). For example, the first to third currents (Ia, Ib, Ic) can be controlled to values ​​at which the following loss indices are minimized.

[0108]

[0109] Here, I a,bal , I b,bal , I c,balis the current applied to the transmitting coil section (130) in an ideal alignment state, and I a,opt , I b,opt , I c,opt is a current applied to the transmitting coil unit (130) controlled by the control unit (110) according to the alignment information.

[0110] According to this, even if wireless charging is performed in a state where the transmitting coil unit (130) and the receiving coil unit (230) are not precisely aligned, the power transmission efficiency between the transmitting coil unit (130) and the receiving coil unit (230) can be maximized.

[0111] According to an embodiment of the present invention, in order to impart intentional asymmetry to the first to third currents (Ia, Ib, Ic), the control unit (110) may control the power factor correction circuit unit (121), the inverter unit (122), or the impedance matching unit (123).

[0112] FIG. 7 is a circuit diagram of a wireless charging system according to one embodiment of the present invention, FIG. 8 is a voltage waveform output from an inverter unit according to the circuit diagram of FIG. 7, and FIG. 9 is a current waveform applied to a transmitting coil unit according to the circuit diagram of FIG. 7.

[0113] Referring to FIG. 7, the wireless power transmission device (100) includes a control unit (110), a power conversion unit (120), and a transmission coil unit (130), and the power conversion unit (120) includes a power factor correction circuit unit (121), an inverter unit (122), and an impedance matching unit (123). Duplicate descriptions of the same contents as those described above with reference to FIGS. 1 to 6 will be omitted.

[0114] According to an embodiment of the present invention, the inverter unit (122) includes a first inverter (122a), a second inverter (122b), and a third inverter (122c), and the control unit (110) controls the first inverter (122a), the second inverter (122b), and the third inverter (122c) to provide intentional asymmetry to the first to third currents (Ia, Ib, Ic). As illustrated, the first inverter (122a), the second inverter (122b), and the third inverter (122c) each include a full-bridge inverter, but are not limited thereto, and the inverter unit (122) may also include a half-bridge inverter.

[0115] The first inverter (122a), the second inverter (122b), and the third inverter (122c) are connected to one power factor correction circuit unit (121). The power factor correction circuit unit (121) is one three-phase PFC and outputs a common DC voltage. The first inverter (122a), the second inverter (122b), and the third inverter (122c), which receive the common DC voltage output from the power factor correction circuit unit (121), can output a first AC voltage (Va), a second AC voltage (Vb), and a third AC voltage (Vc). The first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) output by the first inverter (122a), the second inverter (122b), and the third inverter (122c) are waveforms controlled by the control unit (110) to provide intentional asymmetry to the first to third currents (Ia, Ib, Ic) based on alignment information between the transmitting coil unit (130) and the receiving coil unit (230). Since a common DC voltage is input to the first inverter (122a), the second inverter (122b), and the third inverter (122c), the amplitudes of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) are the same, but the duty ratios may be different through phase shift control. As illustrated in FIG. 8, the duty ratios of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may all be different, or the duty ratio of one of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may be different from the duty ratios of the other two. In this way, if intentional asymmetry is applied to the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) output from the inverter unit (122), the first to third currents (Ia, Ib, Ic) applied to the transmitting coil unit (130) may also be generated asymmetrically.That is, as illustrated in FIG. 9, at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from each other, or at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from each other. For example, the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may all be different from each other, or one of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from the other two. For example, the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may all be different from each other, or one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from the other two.

[0116] In this way, when a current having an optimized amplitude and phase is applied to each of the first to third transmitting coil units (131, 132, 133) of the transmitting coil unit (130) based on the alignment information between the transmitting coil unit (130) and the receiving coil unit (230), even if wireless charging is performed in a state where the transmitting coil unit (130) and the receiving coil unit (230) are not precisely aligned, the loss between the transmitting coil unit (130) and the receiving coil unit (230) can be minimized, thereby maximizing the power transmission efficiency.

[0117] FIG. 10 is a circuit diagram of a wireless charging system according to another embodiment of the present invention, FIG. 11 is a voltage waveform output from an inverter unit according to the circuit diagram of FIG. 10, and FIG. 12 is a current waveform applied to a transmitting coil unit according to the circuit diagram of FIG. 10.

[0118] Referring to FIG. 10, the wireless power transmission device (100) includes a control unit (110), a power conversion unit (120), and a transmission coil unit (130), and the power conversion unit (120) includes a power factor correction circuit unit (121), an inverter unit (122), and an impedance matching unit (123). Duplicate descriptions of the same contents as those described above with reference to FIGS. 1 to 6 will be omitted.

[0119] According to an embodiment of the present invention, the inverter unit (122) includes a first inverter (122a), a second inverter (122b), and a third inverter (122c), and the control unit (110) controls the impedance matching unit (123) to impart intentional asymmetry to the first to third currents (Ia, Ib, Ic). As illustrated, the first inverter (122a), the second inverter (122b), and the third inverter (122c) each include a full-bridge inverter, but are not limited thereto, and may also include a half-bridge inverter.

[0120] The first inverter (122a), the second inverter (122b), and the third inverter (122c) are connected to one power factor correction circuit unit (121). The power factor correction circuit unit (121) is one three-phase PFC and outputs a common DC voltage. The first inverter (122a), the second inverter (122b), and the third inverter (122c) can output a first AC voltage (Va), a second AC voltage (Vb), and a third AC voltage (Vc). As illustrated in Fig. 11, the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) output by the first inverter (122a), the second inverter (122b), and the third inverter (122c) are waveforms that have the same amplitude and a phase difference of 120 degrees. Unlike the embodiments illustrated in FIGS. 7 to 9, the duty ratios of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) are all the same. However, according to the embodiments illustrated in FIGS. 10 to 12, the first to third currents (Ia, Ib, Ic) applied to the transmitting coil unit (130) may be generated asymmetrically by the variable capacitor included in the impedance matching unit (123). That is, as illustrated in FIG. 12, at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from each other, or at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from each other. For example, the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may all be different from each other, or one of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from the other two.For example, the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may all be different from each other, or one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from the other two.

[0121] FIG. 13 is a circuit diagram of a wireless charging system according to another embodiment of the present invention, FIG. 14 is a flowchart of a wireless power transmission method according to the circuit diagram of FIG. 13, FIG. 15 is a voltage waveform output from an inverter unit according to the circuit diagram of FIG. 13, FIG. 16 is a current waveform applied to a transmission coil unit according to the circuit diagram of FIG. 13, and FIG. 17 shows a voltage waveform and an inverter current waveform output from an inverter unit according to the circuit diagram of FIG. 13 together.

[0122] Referring to FIGS. 13 to 14, the wireless power transmission device (100) includes a control unit (110), a power conversion unit (120), and a transmission coil unit (130), and the power conversion unit (120) includes a power factor correction circuit unit (121), an inverter unit (122), and an impedance matching unit (123). Duplicate descriptions of the same contents as those described above with reference to FIGS. 1 to 6 will be omitted.

[0123] More specifically, referring to FIGS. 13 and 14, the power conversion unit (120) of the wireless power transmission device (100) converts power received from the power supply device (300) (S1400), and applies the current output through step S1400 to the first transmission coil (131), the second transmission coil (132), and the third transmission coil (133) (S1410).

[0124] In step S1400, the power factor correction circuit unit (121) outputs the power received from the power supply device (300) as a first DC voltage, a second DC voltage, and a third DC voltage (S1402), and the inverter unit (122) outputs the first DC voltage, the second DC voltage, and the third DC voltage output by the power factor correction circuit unit (121) as a first AC voltage, a second AC voltage, and a third AC voltage (S1404).

[0125] To this end, the power factor compensation circuit unit (121) includes a first power factor compensation circuit (121a), a second power factor compensation circuit (121b), and a third power factor compensation circuit (121c), and the inverter unit (122) includes a first inverter (122a), a second inverter (122b), and a third inverter (122c), and the control unit (110) controls the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) based on alignment information between the transmitting coil unit (130) and the receiving coil unit (230), and accordingly, the first to third currents (Ia, Ib, Ic) applied to the first to third transmitting coils (131, 132, 133) can be asymmetrically controlled to have an optimal combination in which a loss index is minimized.

[0126] Accordingly, based on the alignment information between the transmitting coil unit (130) and the receiving coil unit (230), the first power factor correction circuit (121a), the second power factor correction circuit (121b), and the third power factor correction circuit (121c) can output independent DC voltages so that the first to third currents (Ia, Ib, Ic) applied to the first to third transmitting coils (131, 132, 133) have minimum loss indices. That is, the first power factor correction circuit (121a) can output a first DC voltage, and the first inverter (122a) that receives the first DC voltage can output a first AC voltage (Va). The second power factor correction circuit (121b) can output a second DC voltage, and the second inverter (122b) that receives the second DC voltage can output a second AC voltage (Vb). The third power factor correction circuit (121c) outputs a third DC voltage, and the third inverter (122c), which receives the third DC voltage, can output a third AC voltage (Vc). Here, at least two of the first DC voltage, the second DC voltage, and the third DC voltage may be different from each other. Here, the first power factor correction circuit (121a), the second power factor correction circuit (121b), and the third power factor correction circuit (121c) are each single-phase PFCs, and receive each phase and the neutral point (n) of a three-phase power supply as input. That is, the input of the first power factor correction circuit (121a) is the first phase power received from the power supply device (300), the input of the second power factor correction circuit (121b) is the second phase power received from the power supply device (300), and the input of the third power factor correction circuit (121c) is the third phase power received from the power supply device (300). At least one of the first power factor correction circuit (121a), the second power factor correction circuit (121b), and the third power factor correction circuit (121c) can be connected to the neutral point (n). Accordingly, the first to third DC voltages can be independently controlled.As in the embodiment of the present invention, each of the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) is a single-phase PFC, and when each phase of a three-phase power supply and a neutral point (n) are input, each phase of the three-phase power supply can be independently controlled, and even if the size of the current applied to the transmitting coil section is small, an induced voltage is easily generated in the receiving coil section, so that the size of the transmitting coil section can be reduced.

[0127] Meanwhile, each of the first inverter (122a), the second inverter (122b), and the third inverter (122c) has a fixed duty ratio and may include a full-bridge inverter. The first inverter (122a), the second inverter (122b), and the third inverter (122c) may output asymmetric first to third AC voltages using independently controlled first to third DC voltages.

[0128] According to an embodiment of the present invention, the control unit (110) controls the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) based on alignment information between the transmitting coil unit (130) and the receiving coil unit (230), and the first to third DC voltages output from the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) are input to the first inverter (122a), the second inverter (122b), and the third inverter (122c) and output as the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc).

[0129] Since first to third DC voltages independently controlled are input to the first inverter (122a), the second inverter (122b), and the third inverter (122c), as illustrated in FIG. 15, the amplitudes of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may all be different, or the amplitude of one of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may be different from the amplitudes of the other two. However, since the duty ratios of the first inverter (122a), the second inverter (122b), and the third inverter (122c) are fixed, the duty ratios of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may all be the same.

[0130] At least one of the amplitude and phase of the first current (Ia) applied to the first transmitting coil (131), at least one of the amplitude and phase of the second current (Ib) applied to the second transmitting coil (132), and at least one of the amplitude and phase of the third current (Ic) applied to the third transmitting coil (133) can be controlled by the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc), and accordingly, the first to third currents (Ia, Ib, Ic) can also be generated asymmetrically. That is, as illustrated in FIG. 16, at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from each other, or at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from each other. For example, the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may all be different from each other, or one of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from the other two. For example, the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may all be different from each other, or one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from the other two.

[0131] Meanwhile, referring to FIG. 17, when the first to third power factor compensation circuits (121a, 121b, 121c) output first to third DC voltages that are independently controlled, as in the circuit diagram of FIG. 13, it can be seen that the first to third inverters (122a, 122b, 122c) can output first to third AC voltages (Va, Vb, Vc) by soft switching.

[0132] According to an embodiment of the present invention, the current applied to the transmitting coil unit (130) of the wireless power transmitting device (100) is controlled based on alignment information between the transmitting coil unit (130) of the wireless power transmitting device (100) and the receiving coil unit (230) of the wireless power receiving device (200), thereby increasing the power transmission efficiency between the transmitting coil unit (130) and the receiving coil unit (230).

[0133] FIG. 18 is a flowchart of a wireless charging method of a wireless charging system according to one embodiment of the present invention, and FIG. 19 is an example of obtaining alignment information between a transmitting coil unit and a receiving coil unit according to one embodiment of the present invention.

[0134] Referring to FIG. 18, the wireless charging system (20) obtains alignment information between the transmitting coil unit (130) of the wireless power transmitting device (100) and the receiving coil unit (230) of the wireless power receiving device (200) using a sensor (S1800), and transmits power to the receiving coil unit (230) through the transmitting coil unit (130) based on the alignment information obtained in step S1800 (S1810). In step S1810, the power conversion unit (120) of the wireless power transmitting device (100) converts the power received from the power supply device (300), and an asymmetric current is applied to the first to third transmitting coils (131, 132, 133) included in the transmitting coil unit (130). For a detailed description thereof, reference may be made to the contents described with reference to FIGS. 1 to 17.

[0135] Referring to FIG. 19, the alignment information acquisition unit (140) included in the wireless power transmission device (100) may include a sensor, and alignment information between the transmitting coil unit (130) and the receiving coil unit (230) may be acquired by the sensor included in the wireless power transmission device (100). For example, the sensor may include a plurality of position sensors (PS1, PS2, PS3, PS4) arranged to be spaced apart from each other between the first to third transmitting coils (131, 132, 133). The plurality of position sensors (PS1, PS2, PS3, PS4) may be ultrasonic sensors. FIG. 19(a) is an example in which a plurality of position sensors (PS1, PS2, PS3, PS4) on the side of the first to third transmitting coils (131, 132, 133) transmit signals to the side of the first to third receiving coils (231, 232, 233) in a state in which the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) are aligned, and FIG. 19(b) is an example in which a plurality of position sensors (PS1, PS2, PS3, PS4) on the side of the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) are not aligned. 233) is an example of transmitting a signal to the side. The alignment information acquisition unit (140) can acquire alignment information between the transmitting coil unit (130) and the receiving coil unit (230) based on signals received by multiple position sensors (PS1, PS2, PS3, PS4) in an aligned state. Here, the alignment information between the transmitting coil unit (130) and the receiving coil unit (230) may be relative position information between the transmitting coil unit (130) and the receiving coil unit (230), and may be the degree of deviation from a precisely aligned state.

[0136] FIG. 20 is a flowchart of a wireless charging method of a wireless charging system according to another embodiment of the present invention, and FIG. 21 is an example of obtaining alignment information between a transmitting coil unit and a receiving coil unit according to another embodiment of the present invention.

[0137] Referring to FIG. 20, the wireless charging system (20) performs a position detection step of obtaining alignment information between the transmitting coil unit (130) of the wireless power transmitter (100) and the receiving coil unit (230) of the wireless power receiver (200) using a current for position detection (S2000), and performs a power transmission step of transmitting power to the receiving coil unit (230) through the transmitting coil unit (130) based on the alignment information obtained in step S2000 (S2010). In step S2010, the power conversion unit (120) of the wireless power transmitter (100) converts the power received from the power supply unit (300), and an asymmetric current is applied to the first to third transmitting coils (131, 132, 133) included in the transmitting coil unit (130). For a detailed description thereof, reference may be made to the contents described with reference to FIGS. 1 to 17.

[0138] Referring to FIG. 21, a current for position detection is applied to the first to third transmitting coils (131, 132, 133) of the wireless power transmitting device (100), and accordingly, an induced voltage may be generated in the first to third receiving coils (231, 232, 233) of the wireless power receiving device (200). FIG. 21(a) is an example in which position detection currents (Iga, Igb, Igc) are applied to the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) in a state in which the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) are aligned, and FIG. 21(b) is an example in which position detection currents (Iga, Igb, Igc) are applied to the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) in a state in which the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) are not aligned. The alignment information acquisition unit (140) can acquire alignment information between the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) based on the voltages (Vva, Vvb, Vvc) induced in the first to third receiving coils (231, 232, 233) in the alignment state. Here, the alignment information between the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) may be relative position information between the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233), and may be the degree of deviation from a precise alignment state.

[0139] According to this, it is possible to obtain alignment information between the transmitting coil unit (130) and the receiving coil unit (230) without adding hardware elements such as a position sensor or auxiliary coil.

[0140] FIG. 22 is an example of a state in which a transmitting coil unit and a receiving coil unit included in a wireless charging system according to an embodiment of the present invention are not aligned, FIG. 23 is a detailed flowchart of a wireless charging method explained through FIGS. 20 to 21, FIG. 24 shows a current applied to the transmitting coil unit in each step of FIG. 23, and FIG. 25 shows a voltage induced in the receiving coil unit in each step of FIG. 23. FIG. 26 is a waveform of a current applied to the transmitting coil unit in a position detection step of a wireless charging method according to an embodiment of the present invention, FIG. 27 is a waveform of a voltage induced in the receiving coil unit when the current of FIG. 26 is applied to the transmitting coil unit in a state in which the transmitting coil unit and the receiving coil unit are aligned, and FIG. 28 is a waveform of a voltage induced in the receiving coil unit when the current of FIG. 26 is applied to the transmitting coil unit in a state in which the transmitting coil unit and the receiving coil unit are not aligned. Fig. 26(b) is an enlarged view of a portion of Fig. 26(a), Fig. 27(b) is an enlarged view of a portion of Fig. 27(a), and Fig. 28(b) is an enlarged view of a portion of Fig. 28(a). Here, the wireless charging method of Fig. 23 can be implemented, for example, by the circuit diagram of Fig. 13 in the present specification.

[0141] Referring to FIG. 22, the transmitting coil unit (130) includes first to third transmitting coils which are three-phase coils, and the receiving coil unit (230) includes first to third receiving coils which are three-phase coils. A state in which the transmitting coil unit (130) and the receiving coil unit (230) are not aligned can be represented by (R, θ). Here, R is the distance between the center of the transmitting coil unit and the center of the receiving coil unit, and θ can be the misaligned angle between the center of the transmitting coil unit and the center of the receiving coil unit. Here, the distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) can be the planar distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230). Here, the planar distance can be the planar distance in which the transmitting coil unit (130) is arranged or the planar distance in which the receiving coil unit (230) is arranged. That is, if the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) overlap in the vertical direction, the distance between the center of the transmitting coil unit (130) and the center of the receiving coil unit (230) can be expressed as 0. Here, the vertical direction may be a direction perpendicular to the plane direction, and may be a direction from the transmitting coil unit (130) toward the receiving coil unit (230). In addition, the angle (θ) may be an angle formed by the transmitting coil unit (130) and the receiving coil unit (230) in the plane direction.

[0142] Referring to FIGS. 23 to 25, a wireless charging method according to an embodiment of the present invention includes a position detection step (S2300) for obtaining alignment information between a transmitting coil unit (130) of a wireless power transmitting device (100) and a receiving coil unit (230) of a wireless power receiving device (200), and a power transmission step (S2320) for transmitting power to a receiving coil unit (230) through a transmitting coil unit (130) based on the alignment information obtained in the position detection step (S2300). The wireless charging method according to an embodiment of the present invention may further include a standby step (S2310) between the position detection step (S2300) and the power transmission step (S2320).

[0143] In the position detection step (S2300), the wireless power transmission device (100) applies a first position detection current (Iga) to the first transmission coil (131) (S2301), applies a second position detection current (Igb) to the second transmission coil (132) (S2302), and applies a third position detection current (Igc) to the third transmission coil (133) (S2303). As illustrated in FIGS. 23, 24, and 26, the first to third position detection currents (Iga, Igb, Igc) may be sequentially applied to the first transmission coil (131), the second transmission coil (132), and the third transmission coil (133) so as not to overlap each other. In the example of the circuit diagram of Fig. 13, after the first position detection current (Iga) is output from the first power factor correction circuit (211a) and the first inverter (212a), the second position detection current (Igb) may be output from the second power factor correction circuit (211b) and the second inverter (212b), and then the third position detection current (Igc) may be output from the third power factor correction circuit (211c) and the third inverter (212c). At this time, the first position detection current (Iga), the second position detection current (Igb), and the third position detection current (Igc) may have the same amplitude. To this end, each of the first power factor correction circuit (211a), the second power factor correction circuit (211b), and the third power factor correction circuit (211c) may output a DC voltage of the same magnitude.

[0144] Next, in the position detection step (S2300), the wireless power receiving device (200) detects the voltage induced in the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) by the first position detection current (Iga) applied to the first transmitting coil (131) (S2304), detects the voltage induced in the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) by the second position detection current (Igb) applied to the second transmitting coil (132) (S2305), and detects the voltage induced in the first receiving coil (231), the second receiving coil (232), and the third receiving coil (233) by the third position detection current (Igc) applied to the third transmitting coil (133) (S2306). As illustrated in FIGS. 23, 25, 27, and 28, when a current (Ig) for position detection is applied to the first to third transmitting coils (131, 132, 133), an induced voltage (Ev) is generated in the first to third receiving coils (231, 232, 233). As illustrated in FIGS. 26 to 28, when a first current (Iga) for position detection is applied to the first transmitting coil (131), an induced voltage (Eva, Evb, Evc) is generated in each of the first to third receiving coils (231, 232, 233). At this time, as illustrated in FIG. 27, when the first position detection current (Iga) is applied to the first transmitting coil (131) while the transmitting coil unit (130) and the receiving coil unit (230) are aligned, the largest induced voltage (Eva) is generated in the first receiving coil (231) facing the first transmitting coil (131), and induced voltages (Evb, Evc) that are superimposed on each other with the same amplitude and phase are generated in the second receiving coil (232) and the third receiving coil (233).In contrast, as illustrated in FIG. 28, when the first position detection current (Iga) is applied to the first transmitting coil (131) in a state where the transmitting coil unit (130) and the receiving coil unit (230) are not aligned, the largest induced voltage (Eva) is generated in the first receiving coil (231) arranged closest to the first transmitting coil (131), but induced voltages (Evb, Evc) whose amplitude and phase do not exactly overlap and are misaligned are generated in the second receiving coil (232) and the third receiving coil (233). Likewise, when a second position detection current (Igb) is applied to the second transmitting coil (132), the largest induced voltage (Evb) is generated in the second receiving coil (232) arranged closest to the second transmitting coil (132), but induced voltages (Eva, Evc) whose amplitude and phase do not exactly overlap and are misaligned are generated in the first receiving coil (231) and the third receiving coil (233). When a third current (Igc) is applied to the third transmitting coil (133), the largest induced voltage (Evc) is generated in the third transmitting coil (233) arranged closest to the third transmitting coil (133), but induced voltages (Eva, Evb) whose amplitude and phase do not exactly overlap and are misaligned are generated in the first receiving coil (231) and the second receiving coil (232).

[0145] Next, in the position detection step (S2300), the wireless power transmission device (100) calculates the mutual inductance between the transmitting coil unit (130) and the receiving coil unit (230) (S2307). Here, the mutual inductance between the transmitting coil unit (130) and the receiving coil unit (230) can be calculated based on the voltage induced in the first to third receiving coils (231, 232, 233) when the position detection current is applied to the first transmitting coil (131), the voltage induced in the first to third receiving coils (231, 232, 233) when the position detection current is applied to the second transmitting coil (132), and the voltage induced in the first to third receiving coils (231, 232, 233) when the position detection current is applied to the third transmitting coil (133). To this end, the wireless power transmission device (100) can receive the induced voltage detected by the wireless power reception device (200) in steps S2304, S2305, and S2306 from the wireless power reception device (200), through the power supply device (300), or through an upper management server (not shown).

[0146] For example, the mutual inductance between the transmitting coil section (130) and the receiving coil section (230) can be calculated as follows.

[0147] The position detection current (Ig) applied to the first to third transmitting coils (131, 132, 133) can be expressed as follows:

[0148]

[0149] The voltage (Ev) induced in the first to third receiving coils (231, 232, 233) can be expressed as follows:

[0150]

[0151] The relationship between the current (Ig), induced voltage (EV), and mutual inductance (Mvg) for position detection can be expressed as follows:

[0152]

[0153] When a current (Iga) for position detection is applied to the first transmitting coil (131), the voltage (Ev1) induced in the first to third receiving coils can be expressed as follows:

[0154]

[0155] When a current (Igb) for position detection is applied to the second transmitting coil (132), the voltage (Ev2) induced in the first to third receiving coils can be expressed as follows:

[0156]

[0157] When a current (Igc) for position detection is applied to the third transmitting coil (133), the voltage (Ev3) induced in the first to third receiving coils can be expressed as follows:

[0158]

[0159] Accordingly, the mutual inductance between the first to third transmitting coils (131, 132, 133) and the first to third receiving coils (231, 232, 233) can be expressed as a 3*3 matrix as follows:

[0160]

[0161] Next, in the position detection step (S2300), the wireless power transmission device (100) detects the relative position between the transmitting coil unit (130) and the receiving coil unit (230) based on the mutual inductance (S2308). The relative position between the transmitting coil unit (130) and the receiving coil unit (230) can be represented by (R,θ) described above with reference to FIG. 22. As (R,θ) converges to (0,0), the transmitting coil unit (130) and the receiving coil unit (230) are precisely aligned, and as (R,θ) moves away from (0,0), the transmitting coil unit (130) and the receiving coil unit (230) move away from the precisely aligned state and become unaligned.

[0162] In the above, the wireless power transmission device (100) is described as calculating the mutual inductance between the transmitting coil unit (130) and the receiving coil unit (230) and detecting the relative position between the transmitting coil unit (130) and the receiving coil unit (230), but is not limited thereto. The mutual inductance and the relative position between the transmitting coil unit (130) and the receiving coil unit (230) may also be detected by the power supply device (300) or an upper management server (not shown).

[0163] Thereafter, the wireless charging system goes through a standby phase (S2310) and then performs a power transmission phase (S2320). For details regarding the power transmission phase (S2320), refer to the contents described with reference to FIGS. 1 to 17. That is, as illustrated in FIGS. 23 to 25, during the power transmission phase (S2320), a first current (Ia) is applied to the first transmitting coil (131), a second current (Ib) is applied to the second transmitting coil (132), and a third current (Ic) is applied to the third transmitting coil (133). At this time, the first current (Ia), the second current (Ib), and the third current (Ic) may be applied simultaneously to the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133). In the power transmission step (S2320), the first current (Ia), the second current (Ib), and the third current (Ic) applied to the first transmitting coil (131), the second transmitting coil (132), and the third transmitting coil (133) may be based on the alignment information acquired in the position detection step (S2300). That is, if the transmitting coil unit (130) and the receiving coil unit (230) are determined to be misaligned as a result of the position detection step (S2300), asymmetry may be imparted to the first current (Ia), the second current (Ib), and the third current (Ic).

[0164] That is, as described with reference to FIGS. 13 to 17, the control unit (110) controls the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) based on the alignment information between the transmitting coil unit (130) and the receiving coil unit (230), and the first to third DC voltages output from the first power factor compensation circuit (121a), the second power factor compensation circuit (121b), and the third power factor compensation circuit (121c) can be input to the first inverter (122a), the second inverter (122b), and the third inverter (122c) to be output as the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc).

[0165] Since independently controlled DC voltages are input to the first inverter (122a), the second inverter (122b), and the third inverter (122c), as illustrated in FIG. 15, the amplitudes of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may all be different, or the amplitude of one of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may be different from the amplitudes of the other two. However, since the duty ratios of the first inverter (122a), the second inverter (122b), and the third inverter (122c) are fixed, the duty ratios of the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc) may all be the same. At least one of the amplitude and phase of the first current (Ia) applied to the first transmitting coil (131), at least one of the amplitude and phase of the second current (Ib) applied to the second transmitting coil (132), and at least one of the amplitude and phase of the third current (Ic) applied to the third transmitting coil (133) can be controlled by the first AC voltage (Va), the second AC voltage (Vb), and the third AC voltage (Vc), and accordingly, the first to third currents (Ia, Ib, Ic) can also be generated asymmetrically. That is, as illustrated in FIG. 16, at least two of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from each other, or at least two of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from each other. For example, the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may all be different from each other, or one of the amplitude of the first current (Ia), the amplitude of the second current (Ib), and the amplitude of the third current (Ic) may be different from the other two.For example, the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may all be different from each other, or one of the phase difference between the first current (Ia) and the second current (Ib), the phase difference between the second current (Ib) and the third current (Ic), and the phase difference between the third current (Ic) and the first current (Ia) may be different from the other two.

[0166] To this end, the control unit (110) included in the wireless power transmission device (100) according to the embodiment of the present invention can control the power factor compensation circuit unit (121) differently in the position detection step (S2300) and the power transmission step (S2320). That is, in the position detection step (S2300), the control unit (110) controls the first to third power factor compensation circuits (121a, 121b, 121c) so that a DC voltage corresponding to the position detection currents (Iga, Igb, Igc) is output, and in the power transmission step (S2320), the control unit (110) can control the first to third power factor compensation circuits (121a, 121b, 121c) so that a DC voltage corresponding to the first to third currents (Ia, Ib, Ic) based on the alignment information is output.

[0167] According to an embodiment of the present invention, as illustrated in FIG. 24, the amplitude of the position detection currents (Iga, Igb, Igc) applied to the first to third transmission coils (131, 132, 133) in the position detection step (S2300) may be smaller than the amplitude of the first to third currents (Ia, Ib, Ic) applied to the first to third transmission coils (131, 132, 133) in the power transmission step (S2320). Accordingly, since alignment information between the transmission coil unit (130) and the reception coil unit (230) can be obtained using a minimum amount of power in the position detection step (S2300), unnecessary power consumption can be reduced.

[0168] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. Control unit, A power conversion unit that converts power received from a power supply device, and It includes a transmitting coil section to which the current output from the power conversion section is applied, The above-mentioned transmitting coil section includes a first transmitting coil, a second transmitting coil, and a third transmitting coil, The above power conversion unit, A power factor correction circuit unit that outputs a DC voltage from power received from the above power supply device, and It includes an inverter unit that outputs the DC voltage received from the above power factor compensation circuit unit as an AC voltage, The above inverter unit outputs a first AC voltage, a second AC voltage, and a third AC voltage, At least two of the amplitude of the first AC voltage, the amplitude of the second AC voltage and the amplitude of the third AC voltage are different from each other, A wireless power transmitter, wherein the duty ratio of the first AC voltage, the duty ratio of the second AC voltage, and the duty ratio of the third AC voltage are the same.

2. In paragraph 1, The above power factor compensation circuit unit includes a first power factor compensation circuit, a second power factor compensation circuit, and a third power factor compensation circuit, The inverter unit includes a first inverter into which a first DC voltage output from the first power factor correction circuit is input, a second inverter into which a second DC voltage output from the second power factor correction circuit is input, and a third inverter into which a third DC voltage output from the third power factor correction circuit is input. A wireless power transmission device, wherein the first AC voltage is output from the first inverter, the second AC voltage is output from the second inverter, and the third AC voltage is output from the third inverter.

3. In paragraph 2, A wireless power transmission device in which the first power factor compensation circuit, the second power factor compensation circuit, and the third power factor compensation circuit are controlled by the control unit based on alignment information between the transmitting coil unit and the receiving coil unit included in the wireless power reception device.

4. In paragraph 2, The input of the first power factor correction circuit is the first phase power received from the power supply device, The input of the second power factor correction circuit is the second phase power received from the power supply device, The input of the third power factor correction circuit is the third phase power received from the power supply device, A wireless power transmission device, wherein at least one of the first power factor compensation circuit, the second power factor compensation circuit, and the third power factor compensation circuit is connected to a neutral point.

5. In paragraph 2, The current output from the power converter includes a first current applied to the first transmitting coil, a second current applied to the second transmitting coil, and a third current applied to the third transmitting coil. A wireless power transmission device, wherein at least one of the amplitude and phase of the first current, at least one of the amplitude and phase of the second current, and at least one of the amplitude and phase of the third current are controlled by the first AC voltage, the second AC voltage, and the third AC voltage.

6. In paragraph 5, At least two of the amplitudes of the first current, the second current, and the third current are different from each other, or A wireless power transmission device, wherein at least two of the phase difference between the first current and the second current, the phase difference between the second current and the third current, and the phase difference between the third current and the first current are different from each other.

7. In paragraph 2, A wireless power transmission device wherein the first inverter, the second inverter, and the third inverter are each full-bridge inverters.

8. In paragraph 1, A wireless power transmission device, wherein the power conversion unit further includes an impedance matching unit disposed between the inverter unit and the transmitting coil unit.

9. Control unit, A power conversion unit that converts power received from a power supply device, and It includes a transmitting coil section to which the current output from the power conversion section is applied, The above-mentioned transmitting coil section includes a first transmitting coil, a second transmitting coil, and a third transmitting coil, The above power conversion unit, A power factor correction circuit unit that outputs a DC voltage from power received from the above power supply device, and It includes an inverter unit that outputs the DC voltage received from the above power factor compensation circuit unit as an AC voltage, The above power factor compensation circuit unit includes a first power factor compensation circuit that outputs a first DC voltage, a second power factor compensation circuit that outputs a second DC voltage, and a third power factor compensation circuit that outputs a third DC voltage. The inverter unit includes a first inverter that outputs the first DC voltage as a first AC voltage, a second inverter that outputs the second DC voltage as a second AC voltage, and a third inverter that outputs the third DC voltage as a third AC voltage. A wireless power transmission device in which the first power factor compensation circuit, the second power factor compensation circuit, and the third power factor compensation circuit are controlled by the control unit based on alignment information between the transmitting coil unit and the receiving coil unit included in the wireless power reception device.

10. In a wireless power transmission method of a wireless power transmission device, A power conversion step for converting power received from a power supply device, and Including a current application step of applying the current output in the power conversion step to the first transmitting coil, the second transmitting coil, and the third transmitting coil, The above power conversion step is, A step of outputting a first DC voltage, a second DC voltage, and a third DC voltage from power received from the above power supply device, and A step of outputting the first DC voltage, the second DC voltage and the third DC voltage as the first AC voltage, the second AC voltage and the third AC voltage, A wireless power transmission method wherein the power conversion step is controlled such that at least two of the amplitude of the first AC voltage, the amplitude of the second AC voltage, and the amplitude of the third AC voltage are different from each other, and the duty ratio of the first AC voltage, the duty ratio of the second AC voltage, and the duty ratio of the third AC voltage are equal to each other.

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