Wireless power supply system and method, and wireless power receiving system

Abstract

[Problem] To provide a wireless power supply system, a wireless power supply method, and a wireless power reception system, wherein impedance matching can be easily performed even when the impedance of a load-side circuit fluctuates. [Solution] In a wireless power supply system (1) that transmits and receives power between a power transmission coil (32) and a power reception coil (41) by means of a magnetic field resonance method, the power reception coil (41) is configured so that a plurality of coil regions (41A, 41B, 41C) having different coil turns can be selected in accordance with the connection positions of a plurality of terminals provided to the power reception coil (41), and the power reception coil (41) is configured so as to transmit power to the power transmission coil (32) and the power reception coil (41) in accordance with the selected coil regions (41A, 41B, 41C). The controller (92) reduces the difference between a load-side impedance, which is the impedance of a circuit from the input end (IE) of the power transmission device (3) to the load (8) side, and an input-side impedance, which is the impedance of a circuit from the input end (IE) of the power transmission device (3) to the AC power supply (5) side, by changing the inductance of the power reception coil (41) by switching the plurality of terminals.

Description

Technical Field

[0001] The present invention relates to a wireless power supply system and method and a wireless power receiving system. Background Art

[0002] In recent years, people have been conducting research and development on wireless power supply systems that utilize magnetic fields. As a power supply method that utilizes magnetic force, the currently known electromagnetic field coupling (electromagnetic induction) method and magnetic field resonance method. The magnetic field resonance method refers to the situation where the magnetic field oscillation generated by the AC current flowing in the resonant circuit of the power transmitting device is transmitted to the resonant circuit of the power receiving device and resonates, thereby transmitting power through the state in which the magnetic fields generated by the coils of each resonant circuit are tightly coupled (magnetic field resonance coupling). Compared with wireless power transmission using the electromagnetic field coupling method, wireless power transmission using the magnetic field resonance method has the advantage of a longer power transmission distance (for example, see Patent Document 1). Although the magnetic field resonance method is also a method that uses magnetic field coupling, for ease of understanding, the method that uses resonance will be referred to as the magnetic field resonance method in the present invention.

[0003] In such a wireless power supply system, in order to efficiently transmit electric power, the impedance of the load-side circuit including the power receiving device and the load as viewed from the input end (IE) of the power transmitting device and the impedance of the power supply side as viewed from the input end (IE) of the power transmitting device must be set equivalently.

[0004] Generally, various parameters of the resonance circuit of the power transmitting device and the resonance circuit of the power receiving device are set in advance so that impedance matching can be achieved when the power transmitting coil of the power transmitting device and the power receiving coil of the power receiving device are located at predetermined relative positions. The main causes of such impedance mismatch are believed to include, for example, changes in the relative positional relationship between the power transmitting coil and the power receiving coil, and changes in the charging state of the load such as a battery or a motor to which the power is supplied.

[0005] Patent document 1 discloses the following structure, in which a resonant element and an excitation element are coupled by electromagnetic induction, and on the power receiving side (power supply target) where AC power is supplied from the resonant element to a rectifier circuit via the excitation element and an automatic matching device, the automatic matching device and the excitation element form an impedance converter, the automatic matching device adjusts the impedance of the resonant circuit with the resonant element in accordance with a coupling coefficient that varies according to a transmission distance, and the excitation element is responsible for impedance matching between the resonant element and the rectifier circuit.

[0006] Furthermore, the following is recorded in Comparative Document 2: in wireless power supply using magnetic field resonance, the strength of magnetic field coupling between the power supply coil and the power transmission coil is changed by switching multiple power supply coils (driving coils), thereby matching the impedance between the load side impedance and the input side impedance.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2011-50140

[0010] Patent Document 2: International Publication No. 2022 / 244730 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] However, if impedance matching is achieved by setting a resonant circuit separate from the receiving coil as in the past, it is necessary to operate the variable inductor and variable capacitor while maintaining the resonant state in response to the change in impedance. Considering their responsiveness, the conditions for maintaining the resonant state and the conditions for matching the impedance cannot be reconciled, and it will be difficult to match the impedance according to the change in the positional relationship between the transmitting coil and the receiving coil. In addition, it is also difficult to match the impedance due to the impedance change caused by the change in the relative load. Moreover, the power receiving device with such an impedance matching function is often expensive because it requires high-performance components. In addition, when the power receiving device is a mobile body or portable equipment, it is not realistic to install a complex mechanism in the power receiving device considering factors such as weight, size, and heat generation.

[0013] Furthermore, in the wireless power supply system described in Patent Document 2, during the switching process of the drive coil, the impedance between the load side impedance and the input side impedance becomes mismatched. Therefore, if the switching of multiple drive coils takes time, when the power supply object is a battery that is stationary, there is a risk of slowing down the power supply speed. In addition, when power is supplied to a moving power supply object, the switching of multiple drive coils cannot follow the movement of the power supply object, so the impedance mismatch state may be prolonged, and depending on the situation, there is a risk of premature power loss.

[0014] Therefore, in order to easily perform impedance matching even when the impedance of the load-side circuit changes, a technical problem to be solved arises, and an object of the present invention is to solve this problem.

[0015] Solutions for solving problems

[0016] To achieve the above object, the wireless power supply system of the present invention comprises: a power transmission device having a power transmission side resonance circuit including a power transmission coil; a power receiving device having a power receiving section having a power receiving side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and the power received by the power receiving coil being supplied to the load; and a control device for controlling the power receiving section. The wireless power supply system transmits and receives power between the power transmission coil and the power receiving coil by using a magnetic field resonance method, and is characterized in that the power receiving coil is configured to select a plurality of coil regions having different numbers of coil turns in accordance with connection positions of a plurality of terminals provided in the power receiving coil, and the control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating the difference between a load side impedance and an input side impedance, the load side impedance being the impedance of a circuit from the input end of the power transmission device to the load side, and the input side impedance being the impedance of a circuit from the input end of the power transmission device to the power supply device side.

[0017] Furthermore, in order to achieve the above-mentioned object, the wireless power supply system of the present invention comprises: a power supply device, which has an AC power supply; a power transmitting device, whose input end is connected to the above-mentioned power supply device and has a power transmitting side resonance circuit including a power transmitting coil; a power receiving device, which has a power receiving unit, which has a power receiving side resonance circuit including a power receiving coil, and the power receiving device can be connected to a load, and the power received by the above-mentioned power receiving coil is supplied to the load; and a control device, which controls the above-mentioned power receiving unit; the wireless power supply system transmits and receives power between the above-mentioned power transmitting coil and the above-mentioned power receiving coil by using a magnetic field resonance method, and is characterized in that the above-mentioned power receiving coil is configured to be able to correspond to a plurality of terminals provided on the above-mentioned power receiving coil. The control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating the difference between the load-side impedance and the input-side impedance. The load-side impedance is the impedance of the circuit from the input end of the power transmitting device to the load side, and the input-side impedance is the impedance of the circuit from the input end of the power transmitting device to the power supply device side. The power transmitting device further includes a driving unit including a driving coil, and the driving coil is arranged in a manner that can be coupled with the magnetic field of the power transmitting coil, and transmits electric power to the power transmitting coil by using a magnetic field resonance method. The control device controls the driving unit in a manner that changes the coupling strength of the magnetic field coupling between the power transmitting coil and the driving coil.

[0018] Furthermore, in order to achieve the above-mentioned object, the wireless power supply system of the present invention comprises: a power transmission device, the power transmission device comprising: a power transmission side resonance circuit including a power transmission coil; a driving unit having a driving coil, the driving coil being arranged in a manner capable of coupling with the magnetic field of the power transmission coil and causing the power transmission coil to transmit power; a reflected power detection unit, the reflected power detection unit being arranged between the power supply device and the driving coil and used to detect the reflected power of the driving coil; a power receiving device, the power receiving device comprising a power receiving unit, the power receiving unit having a power receiving side resonance circuit including a power receiving coil, the power receiving device being capable of being connected to a load, and the power received by the power receiving coil being supplied to the load; and a control device, the control device The wireless power supply system transmits and receives the power supplied by the power supply device between the power transmission coil and the power receiving coil by means of magnetic field resonance. The drive coil is constructed in a manner that a plurality of drive coil portions can be selected, and power is transmitted to the power transmission coil by means of magnetic field resonance. The control device switches the plurality of drive coil portions and changes the coupling strength of the magnetic field coupling between the power transmission coil and the drive coil in accordance with the power reflection rate or the power reflection coefficient, based on a correspondence relationship between a power reflection rate or a power reflection coefficient calculated based on the reflected power and the coupling strength of the magnetic field coupling between the power transmission coil and the drive coil stored in advance.

[0019] Furthermore, in order to achieve the above object, a wireless power receiving system of the present invention receives electric power transmitted by a magnetic field resonance method from a power transmitting device having a power transmitting side resonance circuit including a power transmitting coil, and is characterized in that the wireless power receiving system has a power receiving unit having a power receiving side resonance circuit including a power transmitting coil, the wireless power receiving system can be connected to a load, and the electric power received by the power receiving coil is supplied to the load; the power receiving coil is configured to select a plurality of coil regions having different numbers of coil turns in accordance with connection positions of a plurality of terminals provided in the power receiving coil, and a control device for controlling the power receiving unit changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating a difference between a load side impedance and an input side impedance, the load side impedance being an impedance of a circuit from an input end of the power transmitting device to a load side, and the input side impedance being an impedance of a circuit from an input end of the power transmitting device to a power supply device side.

[0020] In order to achieve the above object, a wireless power supply method of the present invention adopts a wireless power supply system, the wireless power supply system comprising: a power transmission device, the power transmission device having a power transmission side resonance circuit including a power transmission coil; a power receiving device, the power receiving device having a power receiving section, the power receiving section having a power receiving side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and the power received by the power receiving coil being supplied to the load; and a control device, the control device controlling the power receiving section; the wireless power supply system transmits and receives power between the power transmission coil and the power receiving coil by using a magnetic field resonance method, characterized in that the power receiving coil is configured to select a plurality of coil regions having different numbers of coil turns corresponding to connection positions of a plurality of terminals provided in the power receiving coil, and the control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating the difference between a load side impedance and an input side impedance, the load side impedance being the impedance of a circuit from the input end of the power transmission device to the load side, and the input side impedance being the impedance of a circuit from the input end of the power transmission device to the power supply device side.

[0021] Effects of the Invention

[0022] The present invention can mitigate the difference between the input side impedance and the load side impedance by changing the coupling strength (density of magnetic field coupling) of the magnetic field coupling between the power transmission coil and the power receiving coil even when the impedance of the load side circuit changes, thereby suppressing the occurrence of reflected waves at the input end and avoiding the reduction in power transmission efficiency and the risk of system failure associated therewith. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram showing the structure of the wireless power supply system according to the first embodiment of the present invention.

[0024] Figure 2 A schematic diagram showing the structure of a driving coil.

[0025] Figure 3 This is a schematic diagram showing the positional relationship between the power transmission coil and three driving coil portions. The three driving coil portions are arranged offset in the axial direction of the coil axis.

[0026] Figure 4 This is a schematic diagram showing the structure of the power receiving coil.

[0027] Figure 5 Schematic diagram showing the positional relationship between the three coil regions of the power transmission coil and the power reception coil.

[0028] Figure 6 This is a schematic diagram showing the electrical wiring of the power receiving coil.

[0029] Figure 7 is a circuit diagram corresponding to the wireless power supply system.

[0030] Figure 8 For Figure 7 The equivalent circuit diagram corresponding to the circuit diagram shown.

[0031] Fig. 9 It is a schematic diagram showing the structure of a first modified example of the wireless power supply system according to the first embodiment.

[0032] Fig.10 It is a schematic diagram showing the structure of a second modified example of the wireless power supply system according to the first embodiment.

[0033] Fig.11 Schematic diagram showing the positional relationship between the power transmission coil and eight power feeding coil units arranged in a substantially spherical shape and tilted relative to the power transmission coil.

[0034] Fig.12 It is a schematic diagram showing the structure of a wireless power supply system according to a second embodiment of the present invention.

[0035] Fig.13 It is a schematic diagram showing the structure of a wireless power supply system according to a third embodiment of the present invention.

[0036] Fig.14 Schematic diagram showing the structure of the driving coil, the power transmission coil, and the power reception coil used in Examples 1 and 2.

[0037] Fig.15 This is a diagram showing the experimental results of Example 1.

[0038] Fig.16 This is a diagram showing the experimental results of Example 2.

[0039] Fig.17 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil in Example 2 when the load resistance is set to 50Ω.

[0040] Fig.18 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil in Example 2 when the load resistance is set to 200Ω.

[0041] Fig.19 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil when the load resistance is set to 500Ω in Example 2.

[0042] Fig. 20 This is a diagram showing the power transmission efficiency in Example 2.

[0043] Fig.213 is a graph showing the experimental results of Example 3 when the load resistance is set to 50Ω.

[0044] Fig. 22 3 is a graph showing the experimental results of Example 3 when the load resistance is set to 500Ω.

[0045] Fig.23 3 is a graph showing the experimental results of Example 3 when the load resistance is set to 3079Ω.

[0046] Fig.24 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil when the load resistance is set to 50Ω in Example 3.

[0047] Fig.25 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil when the load resistance is set to 500Ω in Example 3.

[0048] Fig.26 This is a table showing the combinations of the driving coil and the power receiving coil at various distances between the power transmitting coil and the power receiving coil when the load resistance is set to 3079Ω in Example 3.

[0049] Fig. 27 Schematic diagram showing the structure of the driving coil, the power transmission coil and the power reception coil used in Examples 4 to 11.

[0050] Fig.28 This is a diagram showing the change in the power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in the fourth embodiment.

[0051] Fig.29 1 is a diagram showing a switching sequence of the drive coil portion of the drive coil and the coil region of the power receiving coil in the fourth embodiment.

[0052] Fig.30 This is a diagram showing the change in the power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in the fifth embodiment.

[0053] Fig.31 1 is a diagram showing a switching sequence of the drive coil portion of the drive coil and the coil region of the power receiving coil in the fifth embodiment.

[0054] Fig.32 This is a diagram showing the change in the power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in the sixth embodiment.

[0055] Fig.33 1 is a diagram showing a switching sequence of the drive coil portion of the drive coil and the coil region of the power receiving coil in the sixth embodiment.

[0056] Fig.34 This is a diagram showing the change in the power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in the seventh embodiment.

[0057] Fig.35 1 is a diagram showing a switching sequence of the drive coil portion of the drive coil and the coil region of the power receiving coil in the seventh embodiment.

[0058] Fig.36 This is a diagram showing the change in the power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in the eighth embodiment.

[0059] Fig.37 1 is a diagram showing a switching sequence of the drive coil portion of the drive coil and the coil region of the power receiving coil in the eighth embodiment.

[0060] Fig.38 This is a diagram showing the experimental results of Example 9.

[0061] Fig.39 It is a graph showing the experimental results of Comparative Example 1.

[0062] Fig.40 This is a diagram showing the transition of the power reflectivity in the first experimental result (stop time 43 seconds) in Example 10.

[0063] Fig.41 This is a diagram showing the transition of the power reflectivity in the second experimental result (stop time 46 seconds) in the example.

[0064] Fig.42 This is a diagram showing the transition of the power reflectivity in the third experimental result (stop time 48 seconds) in Example 10.

[0065] Fig.43 This is a diagram showing the transition of the power reflectivity in the fourth experimental result (stop time 43 seconds) in Example 10.

[0066] Fig.44 Graph showing transition of the power reflectivity in the first experimental result (stop time 36 seconds) in Comparative Example 2.

[0067] Fig.45 Graph showing transition of the power reflectivity in the second experimental result (stop time 41 seconds) in Comparative Example 2.

[0068] Fig.46 This is a graph showing the transition of the power reflectivity in the third experimental result (stop time 33 seconds) in Comparative Example 2.

[0069] Fig.47Graph showing transition of the power reflectivity in the fourth experimental result (stop time 33 seconds) in Comparative Example 2.

[0070] Fig.48 This is a diagram showing the change in power reflectivity according to the change in the distance between the power transmission coil and the power reception coil in Example 11. DETAILED DESCRIPTION

[0071] A wireless power supply system 1A according to an embodiment of the present invention and a wireless power supply method using the wireless power supply system 1A are described based on the accompanying drawings. In addition, in the following, when referring to the number, value, amount, range, etc. of constituent elements, except for cases where it is specifically stated and the case where it is obviously limited to a specific number in principle, it is not limited to the specific number and can be more than or less than the specific number.

[0072] Furthermore, when referring to the shapes and positional relationships of components, shapes that are substantially similar to or similar to the shapes are included, except for cases where it is particularly noted or where it is obvious that this is not the case in principle.

[0073] In addition, the drawings may be exaggerated by enlarging characteristic parts for easy understanding of the features, and the dimensional ratios of the components may not be the same as the actual ones. In addition, in the cross-sectional views, the hatching of some components may be omitted for easy understanding of the cross-sectional structure of the components.

[0074] <Structure of wireless power supply system>

[0075] Figure 1 Schematic diagram showing the structure of a wireless power supply system 1A. The wireless power supply system 1A uses magnetic field resonance to supply power to a power supply object 2 in a non-contact manner. The power supply object 2 is, for example, a vehicle, a robot flying object, an underwater robot, a capsule endoscope, a pacemaker, etc., and can be any of a movable device or an immovable device. In addition, when supplying power, the power supply object 2 can be in any of the situations of moving or stopping. The wireless power supply system 1A includes a power transmission device 3 and a power receiving device 4. In addition, the wireless power supply system 1A can include a power supply device 5A having an AC power supply 5.

[0076] <Structure of power transmission device>

[0077] The power transmission device 3 includes a driving coil 31 , a power transmission coil 32 , and capacitors 33 and 34 .

[0078] The drive coil 31 and the power transmission coil 32 are formed by winding a copper wire with high conductivity into a circle. In addition, the current flowing in the copper wire flows more near the surface of the copper wire than in the center due to the influence of internal resistance. Therefore, when the wire material of the drive coil 31 and the power transmission coil 32 uses a stranded wire formed by twisting multiple copper wires, the surface area of ​​the stranded wire becomes larger than that of a single copper wire of the same diameter, and more current can flow, which can suppress current loss.

[0079] AC power is supplied to the driving coil 31 from the AC power supply 5 of the power supply device 5A. The AC power is set to, for example, a frequency of 150 kHz and a voltage of 10 V, but the frequency and voltage of the AC power supply 5 can be changed arbitrarily. Hereinafter, the contact point on the AC power supply 5 side of the driving coil 31 is referred to as the "input terminal IE". In addition, in the present embodiment, the case where the driving coil 31 and the AC power supply 5 are directly connected via the input terminal IE is used as an example for explanation, but the driving coil 31 and the AC power supply 5 can be directly connected via the input terminal IE or indirectly connected via a coaxial cable or the like provided between the AC power supply 5 and the input terminal IE. In this case, if the impedance of the power supply matches the impedance of the coaxial cable or the like, there will be no reflection of power on the power supply side end of the coaxial cable or the like, so there will be no problem. The input terminal IE refers to the load side end of the coaxial cable or the like.

[0080] The driving unit 35 has a power supply side resonance circuit formed by connecting the driving coil 31 and the capacitor 33 in series. When an AC voltage of a frequency corresponding to the resonance frequency set by the inductance of the driving coil 31 and the capacitance of the capacitor 33 flows through the driving coil 31, a vibrating magnetic field is generated in a manner that penetrates the driving coil 31. The detailed structure of the driving coil 31 will be described later.

[0081] The driving coil 31 and the power transmission coil 32 are coupled to each other by a magnetic field resonance method, and the driving coil 31 supplies power to the power transmission coil 32 by a magnetic field resonance method. That is, the design is such that the resonant frequency set according to the inductance of the driving coil 31 and the capacitance of the capacitor 33 is substantially equal to the resonant frequency set according to the inductance of the power transmission coil 32 and the capacitance of the capacitor 34, and the driving coil 31 and the power transmission coil 32 resonate. As a result, the vibration of the magnetic field of a specific frequency (resonant frequency) generated by the AC current flowing through the driving coil 31 is transmitted to the power transmission coil 32 and resonates at the same specific frequency, thereby generating an electromotive force in the power transmission coil 32. In addition, the supply of power from the driving coil 31 to the power transmission coil 32 is preferably a magnetic field resonance method that reduces the influence of the positional relationship of each coil, but it may also be an electromagnetic field coupling method that generates an electromotive force in the power transmission coil 32 through the magnetic flux generated in a manner that penetrates the driving coil 31 in the coil axis direction when the AC current flows through the driving coil 31. In addition, the magnetic field resonance method and the electromagnetic field coupling method may be used in combination.

[0082] The power transmission unit 36 ​​includes a power transmission side resonance circuit formed by connecting a power transmission coil 32 and a capacitor 34 in series. When an AC voltage having a frequency corresponding to a resonance frequency set by the inductance of the power transmission coil 32 and the capacitance of the capacitor 33 flows through the power transmission coil 32, a power receiving coil 41 described later resonates to generate an electromotive force.

[0083] A reflected power detection unit 37 composed of a directional coupler is provided between the AC power source 5 and the drive coil 31 . The reflected power detection unit 37 detects reflected power from the drive coil 31 .

[0084] <Structure of power receiving device>

[0085] The power receiving device 4 is provided in the power supply target object 2 . The power receiving device 4 includes a power receiving coil 41 and a capacitor 42 .

[0086] The receiving coil 41 and the transmitting coil 32 are spaced apart in the coil axial direction. The receiving coil 41 is formed by winding a copper wire with high conductivity into a circle. In addition, the receiving coil 41 is preferably made of a litz wire as a wire material, similar to the driving coil 31 and the transmitting coil 32.

[0087] The power receiving unit 43 has a power receiving side resonance circuit formed by connecting the power receiving coil 41 and the capacitor 42 in series. The resonance frequency set by the inductance of the power receiving coil 41 and the capacitance of the capacitor 42 is set so as to substantially match the resonance frequency of the power transmitting coil 32 and the capacitor 33. As a result, due to the vibration of the magnetic field generated in a manner penetrating the power transmitting coil 32 in the coil axis direction, an induced current flows through the power receiving coil 41, and a vibrating magnetic field is generated in a manner penetrating the power receiving coil 41 in the coil axis direction. In this case, the magnetic fields of the power transmitting coil 32 and the power receiving coil 41 resonate and are firmly coupled. The detailed structure of the power receiving coil 41 will be described later.

[0088] The AC power received by the power receiving coil 41 through resonance is supplied to a load 8 via a rectifier circuit (AC-DC converter) 6 and a DC-DC converter 7. The load 8 is a motor, a battery, or the like constituting the object 2 to be powered.

[0089] The rectifier circuit 6 has four diodes 61 arranged on a bridge, performs full-wave rectification on the AC power received by the power receiving coil 41, and outputs a DC voltage. Reference numeral 62 is a capacitor for smoothing the DC voltage outputted from the rectifier circuit 6.

[0090] The DC-DC converter 7 converts the rectified DC voltage into a preset constant voltage (eg, 12 V). The voltage output from the DC-DC converter 7 is applied to the load 8. The DC-DC converter 7 may be configured to correspond to the required voltage, or may be omitted as appropriate.

[0091] <Structure of impedance matching mechanism>

[0092] Next, the impedance matching mechanism 9 for performing impedance matching processing is described with reference to the drawings. The impedance matching processing is used to mitigate the difference between the impedance of the circuit (load side circuit) from the input end IE to the power receiving device 4 side, that is, including the power transmission device 3, the power receiving device 4, the rectifier circuit 6, the DC-DC converter 7 and the load 8 (hereinafter referred to as "load side impedance") and the impedance of the circuit on the AC power supply 5 side from the input end IE (hereinafter referred to as "input side impedance"). In addition, the power transmission device 4 and the impedance matching mechanism 9 constitute a wireless power transmission system 11.

[0093] like Figure 2 As shown, the impedance matching mechanism 9 supplies power to at least one of the three drive coil portions 31A, 31B, and 31C constituting the drive coil 31 through switching control of switches 91a to 91d. In addition, other structures may be used instead of switches 91a to 91d as long as power can be selectively supplied to any one of the drive coil portions 31A, 31B, and 31C.

[0094] The driving coil 31 is divided into three driving coil parts 31A, 31B, and 31C. The three driving coil parts 31A, 31B, and 31C divide the driving coil 31 into three and are substantially connected in series. The driving coil parts 31A and 31B are connected via wiring 31AB, and the driving coil parts 31B and 31C are connected via wiring 31BC. In addition, the wiring 31AB and 31BC can also be omitted, and it does not matter if the driving coil parts 31A, 31B, and 31C are respectively composed of different driving coils. The coil axes 31a, 31b, and 31c of the driving coil parts 31A, 31B, and 31C are generally coaxial with the coil axis 32a of the power transmission coil 32 in the normal state. In addition, the following is an example of dividing the driving coil 31 into three parts of the driving coil parts 31A, 31B, and 31C, but the number of driving coil parts can be two or more than four.

[0095] The driving coil units 31A, 31B, and 31C are arranged so that the driving coil unit 31A is closest to the power transmission coil 32 and is sequentially separated from the power transmission coil 32. Therefore, the driving coil unit 31A is set to be the strongest and the driving coil unit 31C is set to be the smallest in terms of the coupling strength of the magnetic field coupling with the power transmission coil 32. When power is transmitted to the driving coil 31 and the power transmission coil 32 by magnetic field resonance, the inductances of the driving coil units 31A, 31B, and 31C are set to be equal, respectively, so that power can be transmitted efficiently.

[0096] Switches 91a to 91d are switches composed of transistors or the like for supplying current to the drive coil portions 31A, 31B, and 31C. Switches 91a and 91b are connected to the AC power supply 5. Switch 91a is configured to be able to switch between one end side of the drive coil portion 31C and the switch 91c side. Switch 91c is configured to be able to switch between one end side of the drive coil portion 31A and one end side of the drive coil portion 31B. In addition, switch 91b is configured to be able to switch between the other end side of the drive coil portion 31C and the switch 91d side. Switch 91d is configured to be able to switch between the other end side of the drive coil portion 31A and the other end side of the drive coil portion 31B.

[0097] When power is supplied to the drive coil portion 31A, the switch 91a is switched to the switch 91c side, the switch 91c is switched to one end side of the drive coil portion 31A, the switch 91b is switched to the switch 91d side, and the switch 91d is switched to the other end side of the drive coil portion 31A. In addition, when power is supplied to the drive coil portion 31B, the switch 91a is switched to the switch 91c side, the switch 91c is switched to one end side of the drive coil portion 31B, the switch 91b is switched to the switch 91d side, and the switch 91d is switched to the other end side of the drive coil portion 31B. In addition, when power is supplied to the drive coil portion 31C, the switch 91a is switched to the drive coil portion 31C side, and the switch 91b is switched to the drive coil portion 31C side.

[0098] In addition, when power is supplied to the drive coil units 31A and 31B, the switch 91a is switched to the switch 91c side, the switch 91c is switched to one end side of the drive coil unit 31A, the switch 91b is switched to the switch 91d side, and the switch 91d is switched to the other end side of the drive coil unit 31B. In addition, when power is supplied to the drive coil units 31B and 31C, the switch 91a is switched to the switch 91c side, the switch 91c is switched to one end side of the drive coil unit 31B, and the switch 91b is switched to the drive coil unit 31C side.

[0099] When supplying power to the drive coil units 31A, 31B, and 31C, the switch 91a is switched to the switch 91c side, the switch 91c is switched to one end side of the drive coil unit 31A, and the switch 91b is switched to the drive coil unit 31B side.

[0100] The controller 92 controls the switching of the switches 91a to 91d according to the magnitude of the reflected power detected by the reflected power detection unit 37. The controller 92 is composed of, for example, a CPU, a memory, etc. In addition, the functions of the controller 92 can be realized by controlling using software or by operating using hardware. The controller 92 is functionally divided into a storage unit 93 and a control unit 94 (see Figure 1).

[0101] Furthermore, the magnetic field coupling strength between the driving coil units 31A, 31B, 31C and the power transmission coil 32 becomes weaker in inverse proportion to the distance between the driving coil units 31A, 31B, 31C and the power transmission coil 32. Figure 3 As shown, by supplying power to any of the driving coil units 31A, 31B, and 31C having different coupling strengths with the power transmission coil 32 , the impedance of the circuit in the power transmission device 3 can be increased or decreased.

[0102] like Figure 4 As shown, the impedance matching mechanism 9 can also select which of the three coil areas 41A, 41B, and 41C of the receiving coil 41 is energized by switching control of switches 91e to 91f. The switches 91e to 91f are connected to two terminals respectively provided between a terminal on one end side of the receiving coil 41 and three receiving coil parts 41a which are substantially divided into approximately the same number of coil turns and are substantially connected in series. Furthermore, the terminal on the other end side of the receiving coil 41 and the switch 91e are connected to the rectifier circuit 6. The switching control of the switches 91e to 91f is performed by the controller 92 in accordance with the magnitude of the reflected power detected by the reflected power detection unit 37. Furthermore, the capacitances C1, C2, and C3 of the capacitor 42 are related to the following Figure 6 In the embodiment of the present invention, the capacitors C1, C2, and C3 in the circuit are corresponding. If any one of the coil regions 41A, 41B, and 41C can be selected, other configurations can be used instead of switches 91e to 91f. In the following, the case where the power receiving coil 41 is divided into three coil regions 41A, 41B, and 41C will be described as an example, but the number of power receiving coil regions may be two or more than four.

[0103] Figure 5 It is a schematic diagram showing that part or all of the power receiving coil 41 is selectively used. Figure 5 (a) shows an example of using a coil area 41A corresponding to the total number of coil turns of the power receiving coil 41. Figure 5 (b) shows an example of using the coil area 41B, which is close to the power transmission coil 32 in the power reception coil 41 and is equivalent to 2 / 3 of the total number of coil turns. Figure 5 (c) illustrates the case where the coil region 41C of the power receiving coil 41, which is close to the power transmitting coil 32 and is equivalent to 1 / 3 of the total number of coil turns, is used. The inductance of the power receiving coil 41 increases in proportion to the number of coil turns of the coil regions 41A, 41B, and 41C. Therefore, the inductance of the coil region 41A becomes the largest, the inductance of the coil region 41B is 2 / 3 of the coil region 41A, and the inductance of the coil region 41C is 1 / 3 of the coil region 41A.

[0104] In order to maintain the resonance state between the power receiving coil 41 and the power transmitting coil 32 , the capacitance of the capacitor 42 is appropriately adjusted according to the selected coil regions 41A, 41B, and 41C. Figure 6 Schematic diagram showing the electrical wiring of the power receiving coil 41. Figure 6 In the figure, the three power receiving coil units are shown separated from each other for easy understanding, but the three power receiving coil units do not necessarily need to be separated.

[0105] Two MOSFETs 95a and 95b constitute a switch 91e, and two MOSFETs 95c and 95d constitute a switch 91f. When the coil region 41A with the inductor (L1+L2+L3) is used, the coil region 41A can be selected by turning off the MOSFET 95a, turning on the MOSFET 95b, turning off the MOSFET 95c, and turning on the MOSFET 95d. In this case, the capacitance C3 of the capacitor 42 works. The value of the capacitance C3 is preset to form a resonant circuit with the inductor (L1+L2+L3).

[0106] Furthermore, when the coil region 41B with the inductor (L1+L2) is used, the coil region 41B can be selected by turning off the MOSFET 95a, turning on the MOSFET 95b, turning on the MOSFET 95c, and turning off the MOSFET 95d. At this time, the capacitance C2 of the capacitor 42 works. The value of the capacitance C2 is preset to form a resonant circuit with the inductor (L1+L2).

[0107] When the coil region 41C with the inductor (L1) is used, the coil region 41C can be selected by turning on the MOSFET 95a and turning off the MOSFET 95b (the MOSFETs 95c and 95d can be turned on or off). At this time, the capacitance C1 of the capacitor 42 works. The value of the capacitance C1 is preset to form a resonant circuit with the inductor L1.

[0108] The controller 92 performs switching control of the switches 91a to 91d according to the magnitude of the reflected power detected by the reflected power detection unit 37. Therefore, no matter which of the coil areas 41A, 41B, and 41C is selected, the resonance state between the power receiving coil 41 and the power transmitting coil 32 can be maintained. In addition, in this embodiment, the switch 91e composed of metal oxide semiconductor field effect transistors 95a and 95b and the switch 91f composed of metal oxide semiconductor field effect transistors 95c and 95d are used, but the arrangement of the switches 91e and 1f is not limited to this.

[0109] Next, the main cause of impedance mismatching, which causes the input side impedance to not match the load side impedance, will be described. The greater the difference between the input side impedance and the load side impedance, the greater the reflection of the power and the lower the power transmission efficiency. Impedance mismatching occurs, for example, when the relative position of the power transmission coil 32 and the power reception coil 41 changes, or when foreign matter is present between the power transmission coil 32 and the power reception coil 41, causing the coupling coefficient between the power transmission coil 32 and the power reception coil 41 to change, or when the load 8 changes due to the battery charging condition, etc., causing the load side impedance to change.

[0110] Impedance mismatch will be based on Figure 7 and Figure 8 Provide specific instructions. Figure 7 A circuit diagram corresponding to the wireless power supply system 1A is shown. Figure 7 The "V" in "Z" indicates the voltage of the power supply 5. s " represents the impedance (input side impedance) of the power supply 5, "R0" represents the parasitic resistance of the driving coil 31, "L0" represents the inductance of the power supply coil 31, and "C0" represents the capacitance of the capacitor 33; "I0" represents the current flowing through the driving coil 31, "R1" represents the parasitic resistance of the power transmission coil 32, "L1" represents the inductance of the power transmission coil 32, "C1" represents the capacitance of the capacitor 34, "I1" represents the current flowing through the power transmission coil 32, and "k 01 ” represents the coupling coefficient between the driving coil 31 and the power transmission coil 32, “R2” represents the parasitic resistance of the power reception coil 41, and “R L ” represents the load resistance of the load 8. “L2” represents the inductance of the power receiving coil 41, “C2” represents the capacitance of the capacitor 42, “I2” represents the current flowing through the power receiving coil 41, and “k 12 ” represents the coupling coefficient between the power transmission coil 32 and the power reception coil 41.

[0111] Figure 8 Based on Figure 7 The equivalent circuit diagram of the circuit diagram shown. Figure 8 The equivalent circuit diagram shown in FIG. 4 shows a state where the driving coil 31 resonates with the power transmission coil 32 and the power transmission coil 32 resonates with the power reception coil 41. The mutual inductance M between the driving coil 31 and the power transmission coil 32 is 01 yes The mutual inductance M between the power transmission coil 32 and the power reception coil 41 12 yes Figure 8 "Z0" in the figure represents the impedance of the circuit between the power source 5 and the driving coil 31, that is, from the input terminal IE of the power transmission device 3 to the load 8 side (load side impedance). "Z1" represents the impedance of the circuit from the driving coil 31 and the power transmission coil 32 to the load 8 side. "Z2" represents the impedance of the circuit from the power receiving coil 41 to the load 8 side. Figure 8 The equivalent circuit shown in FIG. 1 gives the following equations 1 to 3.

[0112] [Mathematical formula 1]

[0113] Z2=R2+R L (1)

[0114] [Mathematical formula 2]

[0115]

[0116] [Mathematical formula 3]

[0117]

[0118] For example, as the power transmission coil 32 and the power reception coil 41 come closer to each other, the coupling coefficient “k 12 " becomes larger, it can be understood from Mathematical Formula 2 that the impedance "Z1" becomes larger, and it can be understood from Mathematical Formula 3 that the impedance "Z0" becomes smaller.

[0119] Therefore, the impedance matching mechanism 9 increases with the coupling coefficient "k 12 " will reduce the inductance "L2" of the power receiving coil 41. This will suppress the increase of impedance "Z1" and the decrease of impedance "Z0" respectively, and maintain impedance matching.

[0120] Specifically, the reflected power detector 37 detects reflected power from the drive coil 31, and the controller 92 monitors whether the impedance "Z0" is lower than a predetermined threshold. That is, whether the distance between the power transmission coil 32 and the power reception coil 41 is close to a predetermined distance is monitored by the magnitude of the reflected power.

[0121] When the impedance "Z0" is lower than a predetermined threshold, the controller 92 switches Figure 4 The switches 91 e to 1 f shown select any one of the coil areas 41A, 41B, and 41C, and change the inductance “ L2 ” of the power receiving coil 41 .

[0122] In addition to changing the inductance "L2" of the power receiving coil 41, the coupling coefficient "k 01 In other words, when the impedance "Z0" is lower than the predetermined threshold, the control unit 94 can control the power receiving unit 43 and the driving unit 35. Specifically, by reducing the inductance "L2" of the power receiving coil 41 and increasing the coupling coefficient "k 01 ", the decrease of impedance "Z0" can be further suppressed. As a result, the power transmission coil 32 and the power receiving coil 41 can further cope with the situation of changing long distances.

[0123] In addition, the control unit 94 may adjust the load side impedance "Z0" in the following order: after adjusting (roughly adjusting) the inductance "L2" of the power receiving coil 41 by selecting the coil areas 41A, 41B, and 41C, Figure 2 The switches 91a to 91d shown in the figure select the drive coil units 31A, 31B, and 31C, and adjust (fine tune) the coupling coefficient "k" between the drive coil 31 and the power transmission coil 32. 01 ”.

[0124] Next, the order in which the controller 92 selects any one of the coil regions 41A, 41B, and 41C by switching the switches 91 e to 91 f according to the change in the reflected power detected by the reflected power detection section 37 will be described.

[0125] First, the reflected power detection unit 37 detects the traveling wave voltage V F and the reflected wave voltage V R The voltage reflection coefficient (Γ can be calculated according to the following mathematical formula 4 and mathematical formula 5 2 ) and power reflectance ratio “S”.

[0126] [Formula 4]

[0127]

[0128] [Mathematical formula 5]

[0129] S = Γ 2 (5)

[0130] Moreover, the theoretical value of the voltage reflection coefficient (Γ) ref ) can be expressed by the following mathematical formula 6.

[0131] [Mathematical formula 6]

[0132]

[0133] According to equations 4 to 6, the load side impedance "Z0" can be expressed by the following equation 7. In equation 7, "Zs" is the power supply side impedance, which is a preset fixed value. According to equation 7, the traveling wave voltage V detected by the reflected power detection unit 37 can be F and the reflected wave voltage V R Calculate the measured value of the load side impedance "Z0".

[0134]

[0135] Next, the first switching method of the controller 92 for the power receiving coil 41 will be described. The first switching method measures the traveling wave voltage V again. F and the reflected wave voltage V RFor example, if the voltage reflection coefficient (Γ) or the reflectivity "S" is greater than a specified value (for example, the reflectivity "S" is greater than 5%), the measured value of the load-side impedance "Z0" obtained according to Formula 7 is compared with the theoretical value of the load-side impedance "Z0" shown in Formula 8 derived from Formulas 2 and 3, and the optimal inductance "L2" of the power receiving coil 41 is calculated so that the theoretical value of the load-side impedance "Z0" is closer to the measured value of the load-side impedance "Z0". The controller 92 selects any one of the coil areas 41A, 41B, and 41C corresponding to the calculated inductance value "L2" of the power receiving coil 41 by switching switches 91e to 91f.

[0136] [Mathematical formula 8]

[0137]

[0138] In Mathematical formula (8), the coupling coefficient “k” between the driving coil 31 and the power transmission coil 32 accompanying the switching of the power reception coil 41 is 01 ” and the coupling coefficient “k 12 " changes slightly and can be ignored when calculating the inductance "L2" of the power receiving coil 41. In addition, α and β in mathematical formula 8 are constants.

[0139] That is, in the first switching method of the power receiving coil 41, the traveling wave voltage V F and the reflected wave voltage V R The measured value of the load side impedance "Z0" is obtained according to Mathematical Formula 7, and the inductance "L2" of the power receiving coil 41 is calculated in such a way as to minimize the difference between the theoretical value of the load side impedance "Z0" and the measured value of the load side impedance "Z0", and the coil areas 41A, 41B and 41C of the power receiving coil 41 are switched.

[0140] After switching the power receiving coil 41, the traveling wave voltage V F and the reflected wave voltage V R For example, if the voltage reflection coefficient (Γ) or the reflection rate "S" is above a specified value (for example, the reflection rate "S" is above 5%), the receiving coil 41 may be switched again so as to minimize the difference between the theoretical value of the load side impedance "Z0" and the actual measured value of the load side impedance "Z0", and the inductance "L2" of the receiving coil 41 may be readjusted until the voltage reflection coefficient (Γ) or the reflection rate "S" is below a specified value.

[0141] Next, the second switching method of the controller 92 for the power receiving coil 41 will be described. In the second switching method, the controller 92 switches the power receiving coil 41 according to the actually measured traveling wave voltage V based on equations 4 and 5. F and the reflected wave voltage V RThe voltage reflection coefficient (Γ) or the power reflection rate "S" is calculated. Furthermore, the controller 92 switches the switches 91e to 91f in such a manner that the coil regions 41A, 41B, and 41C of the power receiving coil 41 corresponding to the calculated voltage reflection coefficient (Γ) or the power reflection rate "S" are realized, based on the correspondence between the previously stored voltage reflection coefficient (Γ) or the power reflection rate "S" and the coil regions 41A, 41B, and 41C where the inductance "L2" of the power receiving coil 41 is optimal at this time.

[0142] Next, the third switching method of the controller 92 for the power receiving coil 41 is introduced. The third switching method monitors the change of the measured voltage reflection coefficient (Γ). When the voltage reflection coefficient (Γ) is greater than a specified value (for example, +0.22) and the power reflection rate "S" is greater than a specified value (for example, the reflection rate "S" is greater than 5%), the coil areas 41A, 41B, and 41C of the power receiving coil 41 are switched by only one level in such a way that the inductance "L2" of the power receiving coil 41 is increased by one level. That is, the switching of the coil areas 41A, 41B, and 41C of the power receiving coil 41 is to switch the coil area 41C to the coil area 41B by one level, and to switch the coil area 41B to the coil area 41A by one level. Furthermore, after the coil areas 41A, 41B, and 41C are switched, the inductance "L2" of the power receiving coil 41 is increased by one level. F and the reflected wave voltage V R The power reflectivity "S" is calculated again, and the calculation is repeated until the power reflectivity "S" is equal to or greater than a predetermined value.

[0143] On the other hand, when the voltage reflection coefficient (Γ) is greater than or equal to a predetermined value (e.g., -0.22) and the power reflection rate "S" is greater than or equal to a predetermined value (e.g., the reflection rate "S" is greater than or equal to 5%), the coil regions 41A, 41B, and 41C of the power receiving coil 41 are switched by one level so that the inductance "L2" of the power receiving coil 41 is reduced by one level. That is, the coil regions 41A, 41B, and 41C of the power receiving coil 41 are switched by one level from the coil region 41A to the coil region 41B and by one level from the coil region 41B to the coil region 41C. Furthermore, after the coil regions 41A, 41B, and 41C are switched, the inductance "L2" of the power receiving coil 41 is reduced by one level. F and the reflected wave voltage V R The power reflectivity "S" is calculated again, and the calculation is repeated until the power reflectivity "S" is equal to or greater than a predetermined value.

[0144] In addition, the control unit 94 may adjust the load side impedance "Z0" in the following order: after adjusting the inductance "L2" of the power receiving coil 41 by selecting the coil areas 41A, 41B and 41C, the control unit 94 may adjust the load side impedance "Z0" by switching the coil areas 41A, 41B and 41C. Figure 2The switches 91a to 91d shown in the figure select the drive coil units 31A, 31B, and 31C to adjust the coupling coefficient "k" between the drive coil 31 and the power transmission coil 32. 01 In this case, the inductance "L2" of the power receiving coil 41 and the coupling coefficient "k" between the driving coil 31 and the power transmitting coil 32 can be changed. 01 ”, so a wide range of impedance matching can be performed with higher accuracy.

[0145] That is, in the case of the first switching method, according to the measured traveling wave voltage V F and the reflected wave voltage V R , measure the traveling wave voltage V F and the reflected wave voltage V R For example, when the reflectivity "S" is greater than a predetermined value (for example, the reflectivity "S" is greater than 5%), the measured value of the load side impedance "Z0" is obtained according to Mathematical Formula 7, and the inductance "L2" of the power receiving coil 41 and the coupling coefficient "k" between the driving coil 31 and the power transmitting coil 32 are calculated in such a way that the difference between the theoretical value of the load side impedance "Z0" calculated according to Mathematical Formula 8 and the measured value of the load side impedance "Z0" is minimized. 01 ”. Then select the inductance “L2” and coupling coefficient “k” that are closest to the calculated value. 01 The driving coil parts 31A, 31B, 31C and the coil areas 41A, 41B, 41C of " are used to switch the driving coil 31 and the power receiving coil 41.

[0146] After switching the power receiving coil 41 temporarily, the traveling wave voltage V F and the reflected wave voltage V R , the actual power reflection rate "S" is obtained according to Mathematical Formula 5. When the power reflection rate "S" is above a specified value (for example, above 5%), the power receiving coil 41 or the driving coil 31 can be switched to fine-tune the power reflection rate "S" until it reaches below the specified value. In addition, the power reflection coefficient (Γ) can be used instead of the power reflection rate "S" to determine whether it is necessary to switch the power receiving coil 41 or the driving coil 31. The order of switching the power receiving coil 41 or the switching of the driving coil 31 can also be changed arbitrarily.

[0147] In the case of the second switching method, it is best to store in advance the following table, which determines the power reflection rate "S" or the power reflection coefficient (Γ), the most suitable inductance "L2" of the power receiving coil 41, and the coupling coefficient "k 01 "The corresponding relationship between them.

[0148] In the case of the third switching method, the inductance "L2" is gradually changed by switching the coil areas 41A, 41B, and 41C of the power receiving coil 41 in sequence, and the coupling coefficient "k" is gradually changed by switching the driving coil parts 31A, 31B, and 31C of the driving coil 31 in sequence. 01 " changes, thereby adjusting the power reflectivity "S" to below the specified value. The driving coil portions 31A, 31B, and 31C of the driving coil 31 are switched as follows: the driving coil portions 31A, 31B, and 31C are switched one level at a time, i.e., from the driving coil portion 31A to the driving coil portion 31B, from the driving coil portion 31B to the driving coil portions 31A and 31C, and from the driving coil portion 31C to the driving coil portion 31B.

[0149] Furthermore, after the driving coil sections 31A, 31B, and 31C of the driving coil 31 and the coil regions 41A, 41B, and 41C of the power receiving coil 41 are switched, the traveling wave voltage V F and the reflected wave voltage V R The power reflection rate "S" is calculated again based on the value of, and the process is repeated until the power reflection rate "S" is greater than the specified value. In this way, impedance matching is performed. Moreover, even if the power reflection coefficient (Γ) is used instead of the power reflection rate "S", it can be determined whether it is necessary to switch the power receiving coil 41 or the driving coil 31.

[0150] Furthermore, the order of switching the receiving coil 41 or the switching of the driving coil 31 can be arbitrarily changed. For example, when the switching of the driving coil 31 is performed first, first, the driving coil parts 31A, 31B, and 31C of the driving coil 31 are switched. When the power reflection rate "S" within the predetermined range cannot be achieved even when the switching limit (for example, the driving coil part 31A or 31C) is reached, after the receiving coil 41 is switched by one level, the driving coil parts 31A to 31C of the driving coil 31 are switched again in sequence. Thereafter, the switching of the driving coil 31 and the switching of the receiving coil 41 are repeated in the same manner until the power reflection rate "S" is equal to or less than the predetermined value. Furthermore, the priority order of the receiving coil 41 and the driving coil 31 can be set so that the receiving coil 41 is given priority. Furthermore, only the receiving coil 41 may be switched without switching the driving coil 31, or only the driving coil 31 may be switched without switching the receiving coil 41.

[0151] Thus, the wireless power supply system 1A related to the present embodiment is configured as follows: a power transmission device 3, the power transmission device 3 having a power transmission side resonance circuit including a power transmission coil 32; a power receiving device 4, the power receiving device 4 having a power receiving unit 43, the power receiving unit 43 having a power receiving side resonance circuit including a power receiving coil 41, the power receiving device 4 being connectable to a load 8, and the power received by the power receiving coil 41 being supplied to the load 8; and a controller 92, the controller 92 controlling the power receiving unit 43; the wireless power supply system 1A uses a magnetic field resonance method to connect the power transmission coil 32 and the power receiving unit 41. Electric power is transmitted and received between the coils 41. The receiving coil 41 is configured to be able to select multiple coil areas 41A, 41B, and 41C with different numbers of coil turns corresponding to the connection positions of the multiple terminals provided on the receiving coil 41. The controller 92 changes the inductance of the receiving coil 41 by switching the multiple terminals, thereby alleviating the difference between the load side impedance and the input side impedance. The load side impedance is the impedance of the circuit from the input end IE of the power transmission device 3 to the load 8 side, and the input side impedance is the impedance of the circuit from the input end IE of the power transmission device 3 to the AC power supply 5 side.

[0152] According to this configuration, when the load-side impedance does not match the input-side impedance, the strength of the magnetic field coupling between the power transmitting coil 32 and the power receiving coil 41 (the sparseness of the magnetic field coupling) is changed by appropriately selecting a plurality of coil areas 41A, 41B, and 41C having different numbers of coil turns, and the difference between the input-side impedance and the load-side impedance is mitigated, thereby suppressing the occurrence of reflected waves at the input end IE, and avoiding system failures caused by a decrease in power transmission efficiency and a decrease in transmitted power.

[0153] Furthermore, in the wireless power supply system 1A of the present embodiment, the controller 92 adjusts the inductance of the selected coil areas 41A, 41B, 41C and the capacitance of the capacitor 42 connected in series with the selected coil areas 41A, 41B, 41C by switching a plurality of terminals, thereby maintaining the magnetic field resonance between the power transmitting coil 32 and the power receiving coil 41.

[0154] According to this configuration, the capacitance of the capacitor 42 is preset to correspond to the inductance of the selected coil region 41A, 41B, 41C so that the magnetic field resonance between the power transmission coil 32 and the power reception coil 41 can be maintained regardless of which coil region 41A, 41B, 41C is selected. Therefore, the magnetic field resonance can be easily maintained.

[0155] In addition, according to the wireless power supply system 1A of this embodiment, the power transmission device 3 further has a driving unit 35 including a driving coil 31, and the driving coil 31 is arranged in a manner that can couple with the power transmission coil 32 in the magnetic field and transmit power to the power transmission coil 32. The controller 92 controls the driving unit 35 in a manner that changes the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31.

[0156] According to this configuration, by changing the coupling strength of the magnetic field coupling between the drive coil 31 and the power transmission coil 32, increasing or decreasing the impedance of the circuit within the drive unit 35, and alleviating the difference between the input side impedance and the load side impedance, the occurrence of reflected waves in the input terminal IE can be suppressed, thereby avoiding system failures caused by a decrease in power transmission efficiency and a reduction in transmitted power.

[0157] In addition, the wireless power supply system 1A of this embodiment is constructed such that the power transmitting device 3 also has a reflected power detection unit 37, which is arranged between the AC power supply 5 and the driving coil 31, and is used to detect the reflected power of the driving coil 31. The controller 92 controls the power receiving unit 43 or the driving unit 35 according to the size of the reflected power detected by the reflected power detection unit 37.

[0158] According to this configuration, the difference between the input side impedance and the load side impedance can be mitigated by changing the coupling strength of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41 or the coupling strength of the magnetic field coupling between the drive coil 31 and the power transmission coil 32 in accordance with the detection result of the reflected power detection unit 37. Therefore, the generation of reflected waves at the input end IE can be suppressed, and system failures caused by a decrease in power transmission efficiency and a decrease in transmitted power can be avoided.

[0159] In addition, the wireless power supply system 1A of the present embodiment is configured such that the power transmission device 3 has: a driving unit 35 including a driving coil 31, wherein the driving coil 31 is arranged in a manner that can couple with the magnetic field of the power transmission coil 32 and transmit power to the power transmission coil 32; a reflected power detection unit 37, wherein the reflected power detection unit 37 is arranged between the power supply device 5A and the driving coil 31, and is used to detect the reflected power of the driving coil 31. The controller 92 selects multiple coil areas 41A, 41B, and 41C by switching multiple terminals based on the correspondence between the power reflectivity or the power reflection coefficient calculated based on the reflected power and the inductance of the power receiving coil 41, which is stored in advance.

[0160] According to this configuration, the optimal coil areas 41A, 41B, and 41C can be set corresponding to the power reflection rate or power reflection coefficient calculated based on the reflected power detected by the reflected power detection unit 37, thereby alleviating the difference between the load-side impedance and the impedance of the circuit from the input terminal IE of the power transmission device 3 to the power supply device 5A side, that is, the input-side impedance. Therefore, the occurrence of reflected waves in the input terminal IE can be suppressed, avoiding a reduction in power transmission efficiency and the risk of system failure associated therewith.

[0161] The wireless power supply system 1A of the present embodiment is constructed such that the controller 92 changes the inductance of the receiving coil 41 in such a manner that the theoretical value of the load side impedance approaches the measured value of the load side impedance calculated based on the power reflection rate or the power reflection coefficient, based on the relationship between the actual measured value of the load side impedance and the power reflection rate or the power reflection coefficient, and the relationship between the theoretical value of the load side impedance and the inductance of the receiving coil 41.

[0162] According to this configuration, by setting the optimum coil regions 41A, 41B, and 41C so that the theoretical value of the load side impedance approaches the measured value of the load side impedance calculated based on the power reflection rate or the power reflection coefficient, the generation of reflected waves at the input end IE can be suppressed.

[0163] Furthermore, the wireless power supply system 1A of the present embodiment is configured such that, when the power reflectivity or power reflection coefficient calculated from the reflected power re-detected by the reflected power detection unit 37 after the inductance of the power receiving coil 41 changes is greater than a specified value, the controller 92 changes the inductance of the power receiving coil 41 again in such a way that the theoretical value of the load side impedance approaches the actual measured value of the load side impedance.

[0164] According to this configuration, even if the theoretical value of the load-side impedance does not necessarily match the measured value due to the environment or interference surrounding the wireless power supply system 1, the occurrence of reflected waves in the input end IE can be further suppressed by repeatedly switching the coil areas 41A, 41B, and 41C in such a way that the power reflectivity or the power reflection coefficient is below a specified value.

[0165] The wireless power supply system 1A of the present embodiment is configured such that the driving coil 31 transmits electric power to the power transmission coil 32 by magnetic field resonance, and the controller 92 controls the driving unit 35 to change the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31 .

[0166] According to this configuration, by changing the strength of the magnetic field coupling between the drive coil 31 and the power transmission coil 32, the impedance of the circuit in the drive unit 35 is increased or decreased, and the difference between the input side impedance and the load side impedance is alleviated, thereby suppressing the occurrence of reflected waves in the input end IE and avoiding system failures caused by reduced power transmission efficiency and reduced power transmission.

[0167] Furthermore, the wireless power supply system 1A of the present embodiment is configured such that the controller 92 switches a plurality of terminals to select the coil areas 41A, 41B, 41C of the receiving coil 41 corresponding to the calculated power reflectivity or power reflection coefficient based on a pre-stored correspondence between the power reflectivity or power reflection coefficient calculated based on the reflected power and the coil areas 41A, 41B, 41C of the receiving coil 41.

[0168] According to this configuration, based on a predetermined corresponding relationship, the coil areas 41A, 41B, and 41C corresponding to the power reflectivity or power reflection coefficient calculated based on the reflected power detected by the reflected power detection unit 37 are set, thereby alleviating the difference between the load side impedance and the impedance of the circuit from the input terminal IE of the power transmission device 3 to the power supply device 5A side, that is, the input side impedance. Therefore, the occurrence of reflected waves in the input terminal IE can be suppressed, avoiding a reduction in power transmission efficiency and the risk of system failure associated therewith.

[0169] Furthermore, the wireless power supply system 1A of the present embodiment is configured such that the power transmission device 3 has: a driving unit 35 having a driving coil 31, wherein the driving coil 31 is arranged in a manner that can couple with the magnetic field of the power transmission coil 32 and transmit power to the power transmission coil 32; a reflected power detection unit 37, wherein the reflected power detection unit 37 is arranged between the power supply device 5A and the driving coil 31, and is used to detect the reflected power of the driving coil 31. When the power reflection coefficient calculated based on the reflected power is greater than a specified value, the controller 92 switches the coil areas 41A, 41B, and 41C by switching a plurality of terminals, thereby making the inductance of the receiving coil 41 one level larger than before the switching. When the power reflection coefficient calculated based on the reflected power is less than a specified value, the controller 92 switches the coil areas 41A, 41B, and 41C by switching a plurality of terminals, thereby making the inductance of the receiving coil 41 one level smaller than before the switching.

[0170] According to this configuration, the power reflection coefficient calculated corresponding to the reflected power detected by the reflected power detection unit 37 is switched by one stage in a manner that reduces the power reflection rate, thereby alleviating the difference between the load side impedance and the impedance of the circuit from the input terminal IE of the power transmission device 3 to the power supply device 5A side, that is, the input side impedance. This can suppress the occurrence of reflected waves in the input terminal IE, thereby avoiding a reduction in power transmission efficiency and the risk of system failure associated therewith.

[0171] Furthermore, the wireless power supply system 1A of the present embodiment is configured to include: a power transmission device 3, the power transmission device 3 including: a power transmission side resonance circuit including a power transmission coil 32; a driving unit 35 including a driving coil 31, the driving coil 31 being arranged in a manner capable of magnetic field coupling with the power transmission coil 32 and transmitting power to the power transmission coil 32; a reflected power detection unit 37, the reflected power detection unit 37 being arranged between the power supply device 5A and the driving coil 31 and used to detect the reflected power of the driving coil 31; a power receiving device 4, the power receiving device 4 including a power receiving unit 43, the power receiving unit 43 including a power receiving side resonance circuit including a power receiving coil 41, the power receiving device 4 being connectable to a load 8, and the power received by the power receiving coil 41 being supplied to the load 8; and a controller 92, The controller 92 controls the driving unit 35; the wireless power supply system transmits and receives power between the power transmission coil 32 and the power receiving coil 41 using a magnetic field resonance method using the power supplied by the power supply device 5A. The driving coil 31 is constructed in a manner that allows selection of multiple driving coil units 31A, 31B, and 31C, and transmits power to the power transmission coil 32 using a magnetic field resonance method. The controller 92 switches multiple driving coil units 31A, 31B, and 31C based on a correspondence between a power reflectivity or a power reflection coefficient calculated based on the reflected power and the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31, thereby changing the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31.

[0172] According to this configuration, based on a predetermined corresponding relationship, the driving coil units 31A, 31B, and 31C corresponding to the power reflectivity or power reflection coefficient calculated based on the reflected power detected by the reflected power detection unit 37 are set, thereby alleviating the difference between the load side impedance and the impedance of the circuit from the input terminal IE of the power transmission device 3 to the power supply device 5A side, that is, the input side impedance. Therefore, the occurrence of reflected waves in the input terminal IE can be suppressed, avoiding a reduction in power transmission efficiency and the risk of system failure associated therewith.

[0173] The wireless power supply method of the present embodiment adopts a wireless power supply system 1A, which is configured as follows: the wireless power supply system 1A includes: a power transmission device 3, the power transmission device 3 has a power transmission side resonance circuit including a power transmission coil 32; a power receiving device 4, the power receiving device 4 has a power receiving unit 43, the power receiving unit 43 has a power receiving side resonance circuit including a power receiving coil 41, the power receiving device 4 can be connected to a load 8, and the power received by the power receiving coil 41 is supplied to the load 8; and a controller 92, the controller 92 controls the power receiving unit 43; wherein the wireless power supply system 1A uses a magnetic field resonance method to transmit the power to the power transmission coil 3 2 transmits and receives electric power to and from a power receiving coil 41, wherein the power receiving coil 41 is configured to select a plurality of coil areas 41A, 41B, and 41C having different numbers of coil turns corresponding to connection positions of a plurality of terminals provided on the power receiving coil 41, and the controller 92 changes the inductance of the power receiving coil 41 by switching the plurality of terminals, thereby alleviating the difference between a load-side impedance and an input-side impedance, wherein the load-side impedance is the impedance of a circuit from an input terminal IE of the power transmitting device 3 to a load 8 side, and the input-side impedance is the impedance of a circuit from an input terminal IE of the power transmitting device 3 to a power supply device 5 side.

[0174] According to this configuration, when the load side impedance does not match the input side impedance, by appropriately selecting a plurality of coil areas 41A, 41B and 41C having different numbers of coil turns and changing the strength of the magnetic field coupling between the power transmitting coil 32 and the power receiving coil 41, the difference between the input side impedance and the load side impedance is mitigated, thereby being able to suppress the occurrence of reflected waves in the input end IE and avoid system failures caused by a decrease in power transmission efficiency and a reduction in transmitted power.

[0175] In addition, the wireless power supply method of this embodiment is configured such that the power transmission device 3 further has a driving unit 35 including a driving coil 31, and the driving coil 31 is arranged in a manner that can couple with the magnetic field of the power transmission coil 32 and transmit power to the power transmission coil 32, and the control unit 92 controls the driving unit 35 in a manner that changes the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31.

[0176] According to this configuration, by changing the strength of the magnetic field coupling between the drive coil 31 and the power transmission coil 32, the impedance of the circuit in the drive unit 35 is increased or decreased, and the difference between the input side impedance and the load side impedance is alleviated. Therefore, the occurrence of reflected waves in the input end IE can be suppressed, and system failures caused by a decrease in power transmission efficiency and a reduction in transmitted power can be avoided.

[0177] Furthermore, the wireless power supply method using the wireless power supply system 1A of the present embodiment is configured as follows: the power transmission device 3 has: a driving unit 35 having a driving coil 31, the driving coil 31 being arranged in a manner capable of magnetic field coupling with the power transmission coil 32 and transmitting power to the power transmission coil 32; a reflected power detection unit 37, the reflected power detection unit 37 being arranged between the power supply device 5A and the driving coil 31, and being used to detect the reflected power of the driving coil 31, the controller 92 selects the multiple coil areas 41A, 41B and 41C by switching the above-mentioned multiple terminals in accordance with the above-mentioned power reflection rate or power reflection coefficient calculated based on the reflected power, the load side impedance of the circuit from the input terminal IE of the power transmission device 3 to the load 8 side, and the impedance of the power receiving coil 41, based on the correspondence relationship between the power reflection rate or power reflection coefficient stored in advance and calculated based on the reflected power.

[0178] According to this configuration, the optimal coil areas 41A, 41B and 41C can be set corresponding to the power reflection rate or power reflection coefficient calculated based on the reflected power detected by the reflected power detection unit 37, thereby alleviating the difference between the load side impedance and the impedance of the circuit from the input terminal IE of the power transmission device 3 to the power supply device 5A side, that is, the input side impedance. Therefore, the occurrence of reflected waves in the input terminal IE can be suppressed, avoiding the possibility of reduced transmission efficiency and the resulting system failure.

[0179] The wireless power supply method of this embodiment is configured such that the driving coil 31 transmits power to the power transmission coil 32 using magnetic field resonance, and the controller 92 controls the driving unit 35 to change the coupling strength of the magnetic field coupling between the power transmission coil 32 and the driving coil 31 .

[0180] According to this configuration, by changing the strength of the magnetic field coupling between the drive coil 31 and the power transmission coil 32, the impedance of the circuit in the drive unit 35 is increased or decreased, and the difference between the input side impedance and the load side impedance is alleviated, thereby suppressing the occurrence of reflected waves in the input end IE and avoiding system failures caused by a decrease in power transmission efficiency and a reduction in transmitted power.

[0181] Furthermore, the wireless power supply method of the present embodiment is configured such that the load side impedance adjustment by the controller 92 is roughly adjusted by switching the terminals of the power receiving coil 41 and then finely adjusted by controlling the drive unit 35 .

[0182] According to this configuration, after roughly adjusting the load side impedance by switching the coil regions 41A, 41B, and 41C of the power receiving coil 41 , the control driving unit 35 finely adjusts the load side impedance, thereby enabling accurate and favorable control of the load side impedance.

[0183] The wireless power receiving system 11 of the present embodiment is configured to receive electric power transmitted by a magnetic field resonance method from a power transmitting device 3, the power transmitting device 3 having a power transmitting side resonance circuit including a power transmitting coil 32, and is characterized in that the wireless power receiving system includes a power receiving unit 43, the power receiving unit 43 having a power receiving side resonance circuit including a power receiving coil 41, the wireless power receiving system can be connected to a load 8, and the electric power received by the power receiving coil 41 is supplied to the load 8; the power receiving coil 41 is configured to be able to select a plurality of coil regions 41A, 41B, and 41C having different numbers of coil turns in accordance with connection positions of a plurality of terminals provided in the power receiving coil 41, and the controller 92 changes the inductance of the power receiving coil 41 by switching the plurality of terminals, thereby alleviating the difference between the load side impedance, which is the impedance of the circuit from the input terminal IE of the power transmitting device 3 to the load 8 side, and the input side impedance, which is the impedance of the circuit from the input terminal IE of the power transmitting device 3 to the AC power supply side.

[0184] According to this configuration, when the load side impedance does not match the input side impedance, it is appropriate to select multiple coil areas 41A, 41B and 41C with different numbers of coil turns, and change the strength of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41, thereby alleviating the difference between the input side impedance and the load side impedance. Therefore, it is possible to suppress the occurrence of reflected waves in the input end IE and avoid system failures caused by a decrease in power transmission efficiency and a reduction in transmitted power.

[0185] In the above embodiment, the load current fluctuation caused by the on / off of the DC-DC converter 7 is taken as an example to explain the main cause of the load side impedance variation, but the main cause of the load side impedance variation is not limited to this.

[0186] For example, in the present embodiment, the configuration in which the input side impedance and the load side impedance are pre-matched when the DC-DC converter 7 is unloaded is used as an example for explanation, but for example, it can also be configured so that the input side impedance and the load side impedance are pre-matched when the DC-DC converter 7 is turned on from unloaded, or when the load side impedance is stabilized after the DC-DC converter 7 is turned on.

[0187] exist Figure 1 In the wireless power supply system 1A shown, the reflected power detection unit 37 is disposed in the power transmission device 3 and provided between the input terminal IE of the power transmission device 3 and the driving coil 31 , but the position of the reflected power detection unit 37 is not limited thereto.

[0188] For example, you can also Fig. 9 As in the wireless power supply system 1B shown in FIG. 1 , the reflected power detection unit 37 is disposed in the power supply device 5A and is disposed between the AC power supply 5 and the input terminal IE of the power transmission device 3. Fig.10As in the wireless power supply system 1C shown in the figure, the input terminal IE of the power transmission device 3 is set in the reflected power detection unit 37, and the reflected power detection unit 37 is configured in the power supply device 5A and the power transmission device 3. Even such wireless power supply systems 1B and 1C can alleviate the difference between the load side impedance and the input side impedance, suppress the occurrence of reflected waves in the input terminal IE, and avoid system failures caused by reduced power transmission efficiency and reduced power transmission. Which of the wireless power supply systems 1A, 1B and 1C is adopted can be appropriately selected according to the location and environment where the wireless power supply system is set, and the configuration of the power supply object 2 and the power transmission device 3.

[0189] Furthermore, since the reflected power detection unit 37 has impedance caused by parasitic resistance or parasitic inductance, the detection value of the reflected power detection unit 37 will have an error. The magnitude of the error in such a detection value is assumed to be different depending on the structure of the power supply object 2 (for example, the operation of a motor drive or battery charging with relatively large impedance fluctuations, or a household appliance with relatively small impedance fluctuations). Therefore, the wireless power transmission devices 1A, 1B and 1C can also be constructed to measure the power of the input terminal IE and the impedance of each power supply side / load side for each system with an external tester, and appropriately select a form with the minimum error or the minimum error change of the reflected power detection unit 37 according to the structure of the power supply object 2. In addition, the error itself based on the detection value of the reflected power detection unit 37 can be offset designed at the design stage, or optimally adjusted by offset adjustment in the factory inspection of each product.

[0190] Next, various modifications of this embodiment will be described. In addition, the configurations of the various modifications other than the configurations described below are the same as those of the above-described embodiment.

[0191] <Variation 1>

[0192] For example, the drive coil 31 of this modification example is Fig.11 As shown in (a) to (c) of FIG. 1 , eight driving coil units 31A to 31H arranged in a spherical shape may be provided.

[0193] The drive coil 31 is composed of drive coil sections 31A to 31H that are tilted with each other in a state where the centers are aligned with each other. The drive coil sections 31A to 31H are divided into eight coils, which are substantially connected in series. The connection relationship between the drive coil sections 31A to 31H is omitted in detail, but it is similar to Figure 2 Similarly, the AC power source 5 is connected by a switch (not shown) or the like so as to be supplied with electric power to at least any one of the driving coil units 31A to 31H.

[0194] like Fig.11As shown in (a), the driving coil portion 31A is accommodated in the power transmission coil 32 in the following manner, in a state where the coil axis 31a and the coil axis 32a of the power transmission coil 32 are substantially consistent, that is, there is no inclination relative to the power transmission coil 32. Fig.11 As shown in (b), the driving coil portion 31C is tilted about 45 degrees relative to the power transmission coil 32, and a portion of the driving coil portion 31C is housed in the power transmission coil 32. Fig.11 As shown in (c), the driving coil portion 31E is tilted about 90 degrees relative to the power transmission coil 32, and a part of it is housed in the power transmission coil 32. In addition, the driving coil portions 31B, 31D, 31F to 31H are tilted about 22.5 degrees, 67.5 degrees, 112.5 degrees, 135 degrees, and 157.5 degrees, respectively, relative to the power transmission coil 32, and a part of them is housed in the power transmission coil 32.

[0195] At this time, the magnetic field coupling between the driving coil 31 and the power transmission coil 32 is denser as the relative area increases. That is, the coil axis 31a of the driving coil portion 31A and the coil axis 32a of the power transmission coil 32 are coaxial, so the magnetic field coupling between the driving coil 31A and the power transmission coil 32 is densest. The magnetic field coupling between the driving coil portion 31E and the power transmission coil 32 is sparsest.

[0196] According to such a configuration, for example, the three drive coil units 31A, 31C and 31E can be switched appropriately to perform impedance matching. That is, when the load side impedance is greater than the input side impedance, Fig.11 As shown in (a), by supplying power to the drive coil unit 31A, the magnetic field coupling between the drive coil 31 and the power transmission coil 32 becomes denser, and the impedance of the circuit in the power transmission device 3 is reduced. As a result, the load side impedance at the input terminal IE is reduced, and the difference with the input side impedance is alleviated.

[0197] On the one hand, when the load side impedance is less than the input side impedance, Fig.11 As shown in (b), by supplying power to the driving coil portion 31C which is inclined relative to the power transmission coil 32 as compared to the driving coil portion 31A, the magnetic field coupling between the driving coil portion 31 and the power transmission coil 32 becomes sparse, and the impedance of the circuit in the power transmission device 3 increases. As a result, the load-side impedance at the input terminal IE increases, and the difference with the input-side impedance is mitigated.

[0198] Furthermore, when the load side impedance is further reduced, as Fig.11 As shown in (c), by supplying power to the driving coil portion 31E orthogonal to the power transmission coil 32, the magnetic field coupling between the driving coil 31 and the power transmission coil 32 becomes sparser, and the impedance of the circuit in the power transmission device 3 is further increased. As a result, the load-side impedance in the input terminal IE increases, and the difference between the load-side impedance and the input-side impedance is mitigated.

[0199] According to such a configuration, since power is selectively supplied to at least any one of the driving coil units 31A to 31H, the coupling strength between the driving coil 31 and the power transmission coil 32 can be adjusted.

[0200] In addition, the number of the driving coil parts constituting the spherical driving coil 31 in this modification is not limited to eight, and any number is acceptable if it is two or more. In addition, the inclination of the driving coil parts 31A to 31H related to this modification with respect to the power transmission coil 32 is set within the range of 0 to 180 degrees, but in consideration of the phase of the coil, it can also be set within the range of -90 to +90 degrees.

[0201] Furthermore, the driving coil 31 is not limited to being housed in the power transmission coil 32, and may be arranged outside the power transmission coil 32. Furthermore, a part of the driving coil parts 31A to 31H may be arranged inside the power transmission coil 32, and the other driving coil parts 31A to 31H may be arranged outside the power transmission coil 32. Furthermore, by configuring the driving coil 31 to have an inclination relative to the power transmission coil 32, the coupling coefficient k can be switched. 01 The geometric series can make the impedance adjustment range of each driving coil 31 substantially constant, thereby performing impedance matching more stably.

[0202] <Variation 2>

[0203] The impedance matching mechanism 9 may be a coil moving mechanism that moves the driving coil 31 relative to the power transmission coil 32 .

[0204] As such a coil moving mechanism, the following mechanism can be considered, for example, while maintaining the coil axes 31a, 31b and 31c basically parallel to the coil axis 32a, the driving coil parts 31A, 31B and 31C are slid in a direction perpendicular to the coil axis 32a in a manner such that the coil axes 31a, 31b and 31c are relatively separated or close (aligned) with respect to the coil axis 32a.

[0205] Here, when the coil axes 31a, 31b, 31c and the coil axis 32a of the power transmission coil 32 are located on the same axis, the magnetic field coupling with the power transmission coil 32 becomes dense (the coupling strength (coupling coefficient) becomes large). On the other hand, if the coil axes 31a, 31b, and 31c are offset in a direction perpendicular to the coil axis 31a relative to the coil axis 32a of the power transmission coil 32, the magnetic field coupling with the power transmission coil 32 becomes sparse (the coupling strength (coupling coefficient) becomes small).

[0206] Furthermore, the impedance can be optimized by finely adjusting the impedance by switching the switches 91a to 91d after roughly adjusting the impedance by moving the drive coil 31 relative to the power transmission coil 32 through the coil moving mechanism. In this case, since the impedance can be finely adjusted at high speed, the optimization can be performed smoothly even when the impedance changes suddenly.

[0207] <Variation 3>

[0208] In the above-mentioned modification 2, a coil moving mechanism is illustrated, in which the drive coil parts 31A, 31B and 31C are slid in a direction perpendicular to the coil axis 32a while maintaining the coil axes 31a, 31b and 31c substantially parallel to the coil axis 32a. However, the coil moving mechanism may also be configured to move the drive coil parts 31A, 31B and 31C parallel to the axial directions of the coil axes 31a, 32a, 33a and the coil axis 32a.

[0209] Here, the closer the driving coil parts 31A, 31B and 31C are to the power transmission coil 32, the denser the magnetic field coupling with the power transmission coil 32 is (the coupling coefficient increases), and the farther the driving coil parts 31A, 31B and 31C are from the power transmission coil 32, the sparser the magnetic field coupling with the power transmission coil 32 is (the coupling coefficient decreases).

[0210] Furthermore, the impedance can be roughly adjusted by moving the drive coil 31 relative to the power transmission coil 32 through the coil moving mechanism, and then the impedance can be finely adjusted by switching the switches 91a to 91d to optimize the impedance. In this case, since the impedance can be finely adjusted at high speed, the optimization can be performed smoothly even when the impedance changes suddenly.

[0211] <Variation 4>

[0212] In the above embodiment, the driving coil 31 is exemplified as being composed of the driving coil parts 31A, 31B and 31C in which the coil axes 31a, 31b and 31c are arranged substantially coaxially. However, the configuration of the driving coil 31 is not limited thereto.

[0213] For example, the driving coil 31 may include driving coil portions 31A, 31B, and 31C, and the coil axes 31a, 31b, and 31c thereof may be arranged offset and spaced apart from each other in substantially parallel relationship.

[0214] At this time, the larger the relative area of ​​the magnetic field coupling between the driving coil 31 and the power transmission coil 32, the denser it is. Moreover, according to the switching control of the switches 91a to 91d, power can be selectively supplied to at least one of the driving coil parts 31A, 31B and 31C, so the strength of the magnetic field coupling between the driving coil 31 and the power transmission coil 32 (the density of the magnetic field coupling) can be adjusted.

[0215] <Variant 5>

[0216] In the above-described embodiment, the driving coil 31 is exemplified as being composed of the driving coil portions 31A, 31B, and 31C formed in substantially the same shape, but the driving coil portions 31A, 31B, and 31C may be different shapes from each other.

[0217] For example, the driving coil 31 can also be constructed into a spiral shape, which is configured so that the coil axes 31a, 31b and 31c are arranged on basically the same axis, and the driving coil parts 31A, 31B and 31C successively make the coil diameter gradually smaller, and the coil height gradually increases, and the coil diameter expands and contracts on basically the same plane.

[0218] At this time, the magnetic field coupling between the driving coil 31 and the power transmission coil 32 is denser as the difference in coil diameter is smaller. Moreover, by switching control of the switches 91a to 91d, power can be selectively supplied to at least one of the driving coil parts 31A, 31B and 31C, so that the coupling strength between the driving coil 31 and the power transmission coil 32 can be adjusted.

[0219] <Variant 6>

[0220] Furthermore, in the driving coil 31, the coil axes 31a, 31b and 31c are arranged on basically the same axis, and at the same time, the driving coil parts 31A, 31B and 31C are arranged on basically the same plane. In addition, the driving coil parts 31A, 31B and 31C are arranged in sequence with the coil diameter gradually decreasing, so it does not matter if the coil diameter gradually decreases from the periphery to the center on the same plane.

[0221] At this time, the smaller the coil diameter difference is, the denser the magnetic field coupling between the drive coil 31 and the power transmission coil 32 is. In addition, since power can be selectively supplied to at least one of the drive coil parts 31A, 31B, and 31C through the switching control of the switches 91a to 91d, the coupling strength (sparseness of the magnetic field coupling) of the magnetic field coupling between the drive coil 31 and the power transmission coil 32 can be adjusted.

[0222] <Second embodiment>.

[0223] Next, a wireless power supply system 1D according to a second embodiment of the present invention will be described with reference to the drawings. Fig.12The schematic diagram of the wireless power supply system 1D of the second embodiment is shown. The wireless power supply system 1D according to the present embodiment is different from the wireless power supply system 1A of the first embodiment in the following points, but the other points are common. Therefore, the common configurations are given the same reference numerals and repeated descriptions are omitted.

[0224] For example, the wireless power supply system 1D of this embodiment maintains impedance matching when the impedance "Z0" changes as the battery corresponding to the load 8 is charged, for example, while the power transmitting device 3 and the power receiving device 4 are fixed in a manner such that the distance between the power transmitting coil 32 and the power receiving coil 41 is kept basically constant.

[0225] The power receiving device 4 is provided between the DC-DC converter 7 and the load 8, and has a measuring unit 96 for measuring at least any one of the load voltage or the load current supplied to the load 8. For example, when power is supplied to the load 8, the load voltage will increase to a constant voltage, and the load current will increase rapidly. Moreover, the load side impedance "Z0" at this time decreases rapidly. On the other hand, the input side impedance "Zs" is fixed at a specified value (for example, 50Ω), and the input side impedance "Zs" and the load side impedance "Z0" do not match, resulting in a reflected wave at the input end IE, which may reduce the power transmission efficiency and cause system failure due to insufficient power transmission. In addition

[0226] Therefore, the controller 92 switches the switches 91a to 91d according to the measurement result of the measuring unit 96 to adjust the coupling strength of the magnetic field coupling between the driving coil 31 and the power transmission coil 32, thereby adjusting the coupling coefficient "k 01 ”, increasing or decreasing the impedance of the circuit in the power transmission device 3. Alternatively, according to the change of the load side impedance “Z0”, the controller 92 switches the switches 91e to 91f, and adjusts the coupling coefficient “k” by adjusting the coupling strength of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41. 12 ”, thereby increasing or decreasing the impedance of the circuit in the power receiving device 4. Therefore, the load-side impedance “Z0” increases, and the difference with the input-side impedance “Zs” is relaxed.

[0227] Through this configuration, the wireless power supply system 1D of this embodiment can change the coupling strength of the magnetic field coupling between the power transmitting coil 32 and the power receiving coil 41, or the coupling strength of the magnetic field coupling between the driving coil 31 and the power transmitting coil 32, according to the measurement result of the measuring unit 96, thereby alleviating the difference between the input side impedance and the load side impedance. Therefore, it is possible to suppress the occurrence of reflected waves in the input end IE, avoid a reduction in power transmission efficiency, and avoid system failures caused by a reduction in transmitted power.

[0228] <Third embodiment>

[0229] Next, a wireless power supply system 1E according to a third embodiment of the present invention will be described with reference to the drawings. Fig.13 FIG. 1 is a schematic diagram of a wireless power supply system 1E according to the third embodiment. The wireless power supply system 1E in this embodiment is different from the wireless power supply system 1A in the first embodiment described above in the following points, but the other configurations are common. Therefore, the common configurations are given the same reference numerals, and repeated descriptions are omitted.

[0230] For example, when the relative position of the power transmission coil 32 and the power receiving coil 41 changes as the object 2 to be powered moves, specifically, when the power receiving coil 41 approaches the power transmission coil 32, the coupling strength of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41 increases, and when the power receiving coil 41 moves away from the power transmission coil 32, the coupling strength of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41 decreases, and the coupling state of the magnetic field coupling between the power transmission coil 32 and the power receiving coil 41 changes. Therefore, the wireless power supply system 1E of this embodiment can maintain impedance matching when the relative position of the power transmission coil 32 and the power receiving coil 41 changes.

[0231] The power transmission device 3 has a relative position measuring unit 38 for measuring the relative position of the power transmission coil 32 and the power receiving coil 41. The relative position measuring unit 38 is, for example, a laser length measuring instrument or a three-dimensional camera. In addition, the relative position measuring unit 38 can be installed in the power receiving device 4. In addition, the relative position measuring unit 38 preferably measures not only the distance between the power transmission coil 32 and the power receiving coil 41, but also the relative inclination of each coil axis. The controller 92 calculates the load side impedance "Z0" corresponding to the measurement result of the relative position measuring unit 38. Moreover, when the load side impedance "Z0" is lower than a predetermined threshold value, the controller 92 selects any one of the coil areas 41A, 41B and 41C by switching the switches 91e~91f, and changes the inductance "L2" of the power receiving coil 41.

[0232] In addition to changing the inductance "L2" of the power receiving coil 41, the coupling coefficient "k 01 In other words, when the impedance "Z0" is lower than the predetermined threshold, the controller 92 can control the power receiving unit 43 and the driving unit 35. Specifically, the controller 92 can change the inductance "L2" of the power receiving coil 41 by selecting the coil regions 41A, 41B, and 41C, and reduce the inductance "L2" of the power receiving coil 41, while switching Figure 2 The switches 91a to 91d shown in FIG. 1 select the drive coil sections 31A, 31B, and 31C to increase the coupling coefficient “k” between the drive coil 31 and the power transmission coil 32. 01 ”, and further suppress the reduction of the impedance “Z0”. As a result, even if the distance between the power transmission coil 32 and the power reception coil 41 is further changed to a longer distance, it can be handled.

[0233] Through this configuration, the wireless power supply system 1E of this embodiment can change the coupling strength of the magnetic field coupling between the power transmitting coil 32 and the power receiving coil 41, or the coupling strength of the magnetic field coupling between the driving coil 31 and the power transmitting coil 32, according to the measurement result of the relative position measuring unit 38, thereby alleviating the difference between the input side impedance and the load side impedance, thereby suppressing the occurrence of reflected waves in the input end IE, avoiding a reduction in power transmission efficiency and system failure caused by a reduction in transmitted power.

[0234] In the above-mentioned embodiments, the driving coil 31, the power transmission coil 32, and the power receiving coil 41 are all in a resonant state in order to suppress the generation of reactive power by setting the imaginary part of the impedance to zero. However, even if the driving coil 31 is not connected to the capacitor 33, for example, only the power transmission coil 32 and the power receiving coil 41 may be set in a resonant state, because although reactive power will be generated in the input impedance, power transmission itself is still possible.

[0235] Furthermore, although the above embodiment is described by taking the configuration of a three-coil system having a driving coil 31, a power transmission coil 32, and a power receiving coil 41 as an example, it is also possible to have a two-coil wireless power supply system having only a power transmission coil 32 and a power receiving coil 41 without providing a driving coil 31. In this case, the load side impedance can be controlled by dividing the power transmission coil 32 into a plurality of power transmission coil sections and configuring the relative position of each power transmission coil section and the power receiving coil 41 to be changed.

[0236] Furthermore, in the two-coil system consisting of the power transmission coil 32 and the power receiving coil 41, in order to change the load-side impedance, if the position of the power transmission coil 32 is moved, the coil axis 32a of the power transmission coil 32 and the coil axis of the power receiving coil 41 are not coaxial, and there is a risk of reducing the power transmission efficiency. In contrast, the three-coil system consisting of the driving coil 31, the power transmission coil 32 and the power receiving coil 41 transmits power to the power transmission coil 32 through the driving coil 31. Therefore, without changing the positional relationship between the power transmission coil 32 and the power receiving coil 41, the coupling strength of the magnetic field coupling between the driving coil 31 and the power transmission coil 32 is adjusted, so that the load-side impedance can be controlled and good power transmission efficiency can be maintained.

[0237] Furthermore, although the above-mentioned embodiments are described by taking the configuration of a three-coil system having a driving coil 31, a power transmission coil 32, and a power receiving coil 41 as an example, a wireless power supply system using a four-coil system may be configured, wherein a second power receiving coil is provided in addition to the power receiving coil 41. In this case, the power receiving coil 41 is set to a resonance frequency that is almost equal to that of the power transmission coil 32, and power is transmitted by a magnetic field resonance method. The power receiving coil 41 and the second power receiving coil are arranged in a non-contact manner, and power is transmitted by an electromagnetic field coupling (electromagnetic induction) method or a magnetic field resonance method. Furthermore, in the four-coil system, since the power transmission coil 32 and the power receiving coil 41 are resonance coils independent of other circuits, the resonance frequency does not change during driving, so the design is easy, and the power transmission distance can be extended.

[0238] Example

[0239] <Example 1>

[0240] The experiment (Example 1) is described. In order to confirm the change of the load side impedance "Z0" and the impedance "Z1" when the load resistance of the load 8 is changed, the wireless power supply system 1A of the first embodiment is used. The driving coil 31, the power transmission coil 32 and the power receiving coil 41 used in this experiment are as follows: Fig.14 shown.

[0241] Driving coil

[0242] The driving coil 31 is formed to have a diameter of 300 mm and is housed in the power transmission coil 32 having a diameter of 350 mm. The driving coil 31 is composed of ten driving coil portions 31A to 31J arranged in a spherical shape at different inclination angles. The driving coil portion 31A is arranged parallel to the power transmission coil 32 (inclination is approximately 0 degrees), the driving coil portion 31B is arranged to be inclined only approximately 10 degrees relative to the power transmission coil 32, the driving coil portion 31C is arranged to be inclined only approximately 20 degrees relative to the power transmission coil 32, the driving coil portion 31D is arranged to be inclined only approximately 30 degrees relative to the power transmission coil 32, the driving coil portion 31E is arranged to be inclined only approximately 40 degrees relative to the power transmission coil 32, the driving coil portion 31F is arranged to be inclined only approximately 50 degrees relative to the power transmission coil 32, the driving coil portion 31G is arranged to be inclined only approximately 60 degrees relative to the power transmission coil 32, the driving coil portion 31H is arranged to be inclined only approximately 70 degrees relative to the power transmission coil 32, the driving coil portion 31I is arranged to be inclined only approximately 80 degrees relative to the power transmission coil 32, and the driving coil portion 31J is arranged perpendicular to the power transmission coil 32 (inclination is approximately 90 degrees).

[0243] The driving coil parts 31A to 31J use Litz wires with a strand diameter of 0.04 mm and a diameter of 0.9 mm, and the inductance is set to 278 μH and the capacitance is set to 4.05 nF.

[0244] Passive coil

[0245] The receiving coil 41 is configured to have four selectable coil regions 41A, 41B, 41C, and 41D. The receiving coil 41 has a diameter of 350 mm and is made of a Litz wire with a strand diameter of 0.04 mm and a diameter of 0.9 mm. The number of coil turns, inductance, and capacitance of each coil region 41A, 41B, 41C, and 41D are set as follows.

[0246] Coil area 41A

[0247] Coil turns: 56, inductance: 1488μH, capacitance: 0.756nF

[0248] Coil area 41B

[0249] Coil turns: 28, inductance: 744μH, capacitance: 1.512nF

[0250] Coil area 41C

[0251] Coil turns: 10, inductance: 266μH, capacitor: 4.234nF

[0252] Coil area 41D

[0253] Coil turns: 5, inductance: 133H, capacitance: 8.367nF

[0254] The resonance frequencies of the resonance circuit including the driving coil 31 , the resonance circuit including the power transmission coil 32 , and the resonance circuit including the power reception coil 41 are each set to 150 Hz.

[0255] Experimental sequence

[0256] First, the receiving coil 41 is fixed to the coil area 41A, and the driving coil 31 is fixed to the driving coil part 31A. In this state, the distance between the transmitting coil 32 and the receiving coil 41 is gradually reduced from 350mm to 50mm, and the load side impedance "Z0" is measured at each distance. The results are as follows Fig.15 shown.

[0257] according to Fig.15 It can be seen that as the power transmission coil 32 and the power receiving coil 41 are closer, the load side impedance "Z0" becomes smaller. This is because according to Mathematical Formulas 1 and 2, as the power transmission coil 32 and the power receiving coil 41 are closer to each other, the coupling coefficient "k 12 " increases, the impedance "Z1" increases, on the other hand, the load side impedance "Z0" decreases.

[0258] <Example 2>

[0259] Next, the experiment (Example 2) is described. In order to confirm that in the wireless power supply system 1A, the optimal drive coil units 31A to 31J and coil areas 41A to 41D are selected in accordance with the value input from the reflected power detection unit 37 so as to maintain the load side impedance "Z0" substantially constant. In addition, the drive coil 31 and the power receiving coil 41 used in this example are the same as those in Example 1.

[0260] Experimental sequence

[0261] In the present embodiment, the load side impedance "Z0" when any one of the drive coil parts 31A to 31J and the coil regions 41A to 41D is selected is obtained in advance through experiments and stored in the storage unit 93, and then the best combination of the drive coil parts 31A to 31J and the coil regions 41A to 41D can be selected to maintain the load side impedance "Z0" at about 50Ω. In addition, it is also possible to configure that the values ​​of the inductance, capacitance, and resonance frequency when the drive coil parts 31A to 31J and the coil regions 41A to 41D are selected are pre-stored in the storage unit 93, and the best drive coil parts 31A to 31J and the coil regions 41A to 41D are selected in accordance with the reflected power detected by the reflected power detection unit 37.

[0262] When the load resistance of the load 8 is changed to 50Ω, 200Ω and 500Ω, the load side impedance "Z0" is measured when the distance between the power transmission coil 32 and the power reception coil 41 gradually approaches 50mm from 350mm. The results are as follows: Fig.16 shown.

[0263] Furthermore, the load resistance is set to 50Ω, and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350mm to 50mm. The table showing the combination of the driving coil 31 and the power reception coil 41 selected at each distance is as follows: Fig.17 Furthermore, the load resistance is set to 200Ω, and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350mm to 50mm. The table showing the combination of the driving coil 31 and the power reception coil 41 selected at each distance is as follows: Fig.18 Furthermore, the load resistance is set to 500Ω, and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350mm to 50mm. The table showing the combination of the driving coil 31 and the power reception coil 41 selected at each distance is as follows: Fig.19 As shown. Again, Figure 17 to Figure 19 The types of driving coils “2-1” to “2-10” in FIG. 1 correspond to the driving coil portions 31A to 31J, respectively, and the types of receiving coils “1-1” to “1-4” correspond to the coil regions 41A to 41D, respectively.

[0264] Furthermore, the transmission efficiency calculated by equation 9 when the load resistance is 50Ω is Fig. 20shown.

[0265] Mathematical formula 9

[0266]

[0267] according to Fig.16 It can be seen that no matter whether the load resistance is 50Ω, 200Ω or 500Ω, when the distance between the power transmission coil 32 and the power reception coil 41 is less than 350mm, the load side impedance "Z0" is maintained at about 50Ω. Fig. 20 It can be seen that the transmission efficiency at this time is maintained at more than about 90%.

[0268] That is, by selecting the optimal coil area 41A to 41D and adjusting the inductance of the power receiving coil 41, the load side impedance "Z0" can be easily controlled and impedance matching can be performed. In addition, by selecting the drive coil parts 31A to 31J, the coupling coefficient "k 01 ", impedance matching can be implemented more conveniently.

[0269] <Example 3>

[0270] Next, an experiment and simulation (Example 3) will be described, in which an experiment and simulation were performed to confirm that in the wireless power supply system 1A, the load side impedance "Z0" is within a predetermined range even when the load resistance changes and the distance between the power transmission coil 32 and the power reception coil 41 changes. The power reception coil 41 used in this example is the same as that in Example 1.

[0271] Driving coil

[0272] In this embodiment, the driving coil 31 is different from the embodiment 1 in that it is composed of six driving coil parts arranged in a spherical shape with different inclination angles. The other structures are the same as those of the embodiment 1. The arrangement of the driving coil parts is as follows so that the coupling coefficient "k 01 "for That is 1.56 times the interval.

[0273] ·Drive coil section No.3-1

[0274] Coupling coefficient "k 01 ”: about 0.45, tilt angle: 0 degrees.

[0275] ·Drive coil section No.3-2

[0276] Coupling coefficient "k 01 ”: about 0.41, tilt angle: 22 degrees.

[0277] ·Drive coil section No.3-3

[0278] Coupling coefficient "k01 ”: about 0.26, tilt angle: 49 degrees.

[0279] ·Drive coil section No.3-4

[0280] Coupling coefficient "k 01 ”: about 0.17, tilt angle: 64 degrees.

[0281] ·Drive coil No.3-5

[0282] Coupling coefficient "k 01 ”: about 0.11, tilt angle: 73 degrees.

[0283] ·Drive coil section No.3-6

[0284] Coupling coefficient "k 01 ”: about 0.07, tilt angle: 79 degrees.

[0285] Experimental sequence

[0286] The load resistance is set to 50Ω, 500Ω and 3079Ω, assuming the charging condition of the load 8, and the load side impedance "Z0" changes when the distance between the power transmission coil 32 and the power reception coil 41 is gradually approached from 350mm to 50mm. Figure 21 to Figure 23 Again, in Fig.21 The load resistance is set to 50Ω. Fig. 22 The load resistance is set to 500Ω. Fig.23 In the example, the load resistance is set to 3079Ω.

[0287] Furthermore, when the load resistance is set to 50Ω and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350 mm to 50 mm, the combinations of the driving coil 31 and the power reception coil 41 selected at each distance are shown as follows: Fig.24 Furthermore, the load resistance is set to 500Ω, and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350mm to 50mm. The combination of the driving coil 31 and the power reception coil 41 selected at each distance is shown as follows: Fig.25 Furthermore, the load resistance is set to 3079Ω, and the distance between the power transmission coil 32 and the power reception coil 41 is gradually increased from 350mm to 50mm. The combination of the driving coil 31 and the power reception coil 41 selected at each distance is shown as follows: Fig.26 As shown. Again, Figure 24 to Figure 26 The types of power receiving coils “1-1” to “1-4” in FIG. 1 correspond to the coil areas 41A to 41D, respectively.

[0288] according to Figure 21 to Figure 23It can be seen that, regardless of whether the load resistance of the load 8 is 50Ω, 500Ω, or 3079Ω, by appropriately selecting the driving coil 31 and the power receiving coil 41, the change in the load side impedance "Z0" can be kept within the range of 32 to 78Ω relative to the target value of 50Ω. That is, a power reflection rate of 5% or less can be achieved, and impedance matching can be achieved regardless of changes in the distance between the power transmission coil 32 and the power receiving coil 41 and changes in the load resistance of the load 8.

[0289] <Example 4>

[0290] The experiment (Example 4) is described, wherein the above-mentioned wireless power supply system 1A is used, and when the distance between the power transmission coil 32 and the power receiving coil 41 changes, the coil portion of the driving coil 31 and the coil area of ​​the power receiving coil 41 are automatically switched to achieve impedance matching. In addition, in this Example 4, the load resistance is constant at 50Ω. In addition, the power supply frequency is set to 150kHz. In addition, the structures of the driving coil 31, the power transmission coil 32 and the power receiving coil 41 used in this experiment are as follows Fig. 27 The power receiving coil 41 used in this embodiment is the same as that in the first embodiment.

[0291] Driving coil.

[0292] The drive coil 31 is formed to have a diameter of 300 mm and is housed in the power transmission coil 32 having a diameter of 350 mm. The drive coil 31 is composed of six drive coil parts 31A to 31F arranged in a spherical shape with different inclination angles. The drive coils 31A to 31F are arranged in such a way that the coupling coefficient "k 01 "for That is 1.56 times the spacing.

[0293] Driving coil unit 31A

[0294] Coupling coefficient "k 01 ”: about 0.45, tilt angle: 0 degrees.

[0295] Driving coil section 32B

[0296] Coupling coefficient "k 01 ”: about 0.41, tilt angle: 22 degrees.

[0297] Driving coil unit 31C

[0298] Coupling coefficient "k 01 ”: about 0.26, tilt angle: 49 degrees.

[0299] Driving coil unit 31D

[0300] Coupling coefficient "k 01 ”: about 0.17, tilt angle: 64 degrees.

[0301] Driving coil unit 31E

[0302] Coupling coefficient "k 01 ”: about 0.11, tilt angle: 73 degrees.

[0303] Driving coil unit 31F

[0304] Coupling coefficient "k 01 ”: about 0.07, tilt angle: 79 degrees.

[0305] The driving coils 31A to 31F are made of Litz wire with a strand diameter of 0.04 mm and a diameter of 0.9 mm, and the inductance is set to 278 μH and the capacitance is set to 4.05 nF.

[0306] The resonance frequencies of the resonance circuit including the driving coil 31 , the resonance circuit including the power transmission coil 32 , and the resonance circuit including the power reception coil 41 are each set to 150 kHz.

[0307] Coil switching method

[0308] The switching between the driving coil 31 and the power receiving coil 41 is performed by the first switching method described above. That is, first, the controller 92 detects the traveling wave voltage V F and the reflected wave voltage V R And mathematical formulas 4 and 5 are used to calculate the reflectivity "S".

[0309] If the reflectivity "S" is above a specified value (e.g., 5%), the controller 92 will F and the reflected wave voltage V R And mathematical formula 6 is used to calculate the measured value of the load side impedance "Z0".

[0310] Next, the controller 92 switches the drive coil sections 31A to 31F of the drive coil 31 so that the difference between the theoretical value of the load side impedance “Z0” calculated according to the mathematical formula 8 and the measured value of the load side impedance “Z0” falls within a predetermined range, thereby changing the coupling coefficient “k” between the drive coil 31 and the power transmission coil 32. 01 ”, by switching the coil areas 41A to 41D of the power receiving coil 41, the inductance “L2” of the power receiving coil 41 is changed.

[0311] After the coil regions 41A to 41D of the power receiving coil 41 are switched, the reflected power detection unit 37 detects the traveling wave voltage V F and the reflected wave voltage V R The controller 92 detects the traveling wave voltage V according to the reflected power detection unit 37. F and the reflected wave voltage V RAnd the reflectivity "S" is calculated again using Mathematical Formulas 4 and 5.

[0312] If the power reflectivity "S" is maintained above a specified value (e.g., 5%), the driving coil 31 and the power receiving coil 41 are repeatedly switched, as in the first switching of the driving coil 31 and the power receiving coil 41 described above, and fine-tuned until the power reflectivity "S" is below the specified value.

[0313] Experimental sequence

[0314] First, the driving coil 31 is set in the driving coil section 31B, and the receiving coil 41 is set in the coil area 41C. In this state, the distance between the power transmission coil 32 and the receiving coil 41 is maintained at 0 mm for about 12 seconds, and then the distance between the power transmission coil 32 and the receiving coil 41 is separated to 350 mm in about 1 second. Next, the distance between the power transmission coil 32 and the receiving coil 41 is maintained at 350 mm for about 15 seconds, and then the distance between the power transmission coil 32 and the receiving coil 41 is shortened to 0 mm in about 1 second. The change of the power reflectivity in this experiment is shown in FIG. Fig.28 As shown. Again, Fig.29 The switching history of the drive coil portions 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 in this experiment is shown.

[0315] exist Fig.29 In the figure, "1" to "6" on the left vertical axis correspond to the drive coil parts 31A to 31F of the drive coil 31, respectively, wherein the drive coil part 31A corresponds to "1", the drive coil part 31B corresponds to "2", the drive coil part 31C corresponds to "3", the drive coil part 31D corresponds to "4", the drive coil part 31E corresponds to "5", and the drive coil part 31F corresponds to "6". Fig.29 , "1" to "4" on the right vertical axis correspond to coil areas 41A to 41D of the power receiving coil 41, coil area 41A corresponds to "4", coil area 41B corresponds to "3", coil area 41C corresponds to "2", and coil area 41D corresponds to "1".

[0316] Experimental results

[0317] according to Fig.28It can be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is separated from 0 mm to 350 mm, the power reflectivity rises to about 0.55 (55%), but in about 1 second, it decreases to less than 0.05 (less than 5%), and then maintains this state. It can also be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is approached from 350 mm to 0 mm, the power reflectivity rises to about 0.52 (52%), but in about 1 second, it decreases to less than 0.05 (less than 5%), and then maintains this state.

[0318] Again, according to Fig.29 It can be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is separated from 0 mm to 350 mm, including the above-mentioned fine adjustment, the driving coil 31 is switched three times and the power receiving coil 41 is switched twice. It can also be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is approached from 350 mm to 0 mm, the driving coil 31 is switched three times and the power receiving coil 41 is switched twice.

[0319] As can be seen from the results of this experiment, regardless of whether the distance between the power transmission coil 32 and the power receiving coil 41 is separated or brought closer, the power reflectivity drops below 5% within 1 second, and impedance matching can be performed very smoothly relative to the change in the distance between the power transmission coil 32 and the power receiving coil 41.

[0320] <Example 5>

[0321] Experiment (Example 5) was conducted. As in Example 4, using the wireless power supply system 1A, when the distance between the power transmission coil 32 and the power reception coil 41 was changed, the drive coil parts 31A to 31F of the drive coil 31 and the coil areas 41A to 41D of the power reception coil 41 were automatically switched to achieve impedance matching.

[0322] In this experiment, the switching between the driving coil 31 and the power receiving coil 41 was performed by the third switching method described above. That is, first, the controller 92 detects the traveling wave voltage V F and the reflected wave voltage V R According to the mathematical formulas 4 and 5, the power reflection coefficient (Γ) and reflectivity "S" are calculated.

[0323] When the power reflection coefficient (Γ) is greater than a predetermined value (e.g., +0.22) and the power reflection rate "S" is greater than a predetermined value (e.g., 5%), the drive coil sections 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 are switched step by step. In this experiment, the switching of the drive coil 31 takes precedence over the switching of the power receiving coil 41.

[0324] The controller 92 detects the traveling wave voltage V according to the reflected power detection unit 37. F and the reflected wave voltage V R The power reflection coefficient (Γ) and reflectivity "S" are calculated again according to Mathematical Formulas 4 and 5.

[0325] If the power reflectivity "S" is maintained above a specified value (e.g., 5%), the switching of the driving coil 31 and the receiving coil 41 is repeated in the same manner as the first switching of the driving coil 31 and the receiving coil 41 mentioned above, and fine-tuning is performed until the power reflectivity "S" is below the specified value.

[0326] Experimental sequence

[0327] First, the driving coil 31 is set in the driving coil section 31B, and the receiving coil 41 is set in the coil area 41C. In this state, the distance between the power transmission coil 32 and the receiving coil 41 is maintained at 0 mm for about 11 seconds, and then the distance between the power transmission coil 32 and the receiving coil 41 is separated to 350 mm in about 1 second. Next, the distance between the power transmission coil 32 and the receiving coil 41 is maintained at 350 mm for about 15 seconds, and then the distance between the power transmission coil 32 and the receiving coil 41 is close to 0 mm in about 1 second. The change of the power reflectivity in this experiment is shown in FIG. Fig.30 As shown. Again, Fig.31 The switching history of the drive coil portions 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 in this experiment is shown.

[0328] Experimental results

[0329] according to Fig.30 It can be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 increases from 0 mm to 350 mm, the power reflectivity increases to about 0.20 (20%), but drops to below 0.05 (below 5%) in about 2 seconds, and then maintains this state. In addition, when the distance between the power transmission coil 32 and the power receiving coil 41 decreases from 350 mm to 0 mm, the power reflectivity increases to about 0.90 (90%), but drops to below 0.05 (below 5%) in about 5 seconds, and then maintains this state.

[0330] Again, according to Fig.31 It can be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is separated from 0 mm to 350 mm, including the above-mentioned fine adjustment, the driving coil 31 and the power receiving coil are switched twice. It can also be seen that when the distance between the power transmission coil 32 and the power receiving coil 41 is close to 0 mm from 350 mm, the driving coil 31 is switched 13 times and the power receiving coil is switched 2 times.

[0331] Thus, it can be seen from the results of this experiment that the power reflectivity drops below 5% within 5 seconds regardless of whether the distance between the power transmission coil 32 and the power reception coil 41 is separated or brought closer, and it can be said that impedance matching can be performed roughly smoothly with respect to the change in the distance between the power transmission coil 32 and the power reception coil 41. However, compared with the experimental results of Example 4, the time until the power reflectivity stabilizes below 5% in this experiment is longer, indicating that Example 4 has a better response.

[0332] <Example 6>

[0333] Experiment (Example 6) was conducted. As in Example 4, the wireless power supply system 1A was used to check the state of the system before impedance matching at startup. In this experiment, the switching between the driving coil 31 and the receiving coil 41 was performed in the first switching mode as in Example 4.

[0334] Experimental sequence

[0335] First, the driving coil 31 is set in the driving coil section 31A, and the receiving coil 41 is set in the coil area 41A. From this initial state, the power is turned on under the conditions that the distance between the power transmission coil 32 and the power reception coil 41 is 50 mm and the load resistance is 50Ω. The change of the power reflectivity in this experiment is shown in Fig.32 As shown. Again, Fig.33 The switching history of the drive coil portions 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 in this experiment is also shown.

[0336] Experimental results

[0337] according to Fig.32 It can be seen that the power reflectivity is about 0.70 (70%) in the initial state, but drops to below 0.05 (below 5%) in about 0.8 seconds and maintains this state thereafter. Fig.33 It can be seen that the driving coil 31 is switched twice, and the power receiving coil 41 is switched once.

[0338] Thus, according to the results of this experiment, it can be understood that the impedance matching state with a power reflectivity of 5% or less is reached within 1 second, and the system startup is very smooth.

[0339] <Example 7>

[0340] Experiment (Example 7) was conducted. As in Example 4, the wireless power supply system 1A was used to check the state of the system before impedance matching at startup. In this experiment, the switching between the driving coil 31 and the receiving coil 41 was performed in the same manner as in Example 5 using the third switching method.

[0341] Experimental sequence

[0342] First, the driving coil 31 is set in the driving coil section 31A, and the receiving coil 41 is set in the coil area 41A. From this initial state, the power is turned on under the conditions that the distance between the power transmission coil 32 and the power reception coil 41 is 50 mm and the load resistance is 50Ω. The change of the power reflectivity in this experiment is shown in Fig.34 As shown. Again, Fig.35 The switching history of the drive coil portions 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 in this experiment is also shown.

[0343] Experimental results

[0344] according to Fig.34 It can be seen that the power reflectivity is about 0.62 (62%) in the initial state, rises temporarily to 0.90 (90%), then drops to below 0.05 (below 5%) in about 2.8 seconds, and remains in this state thereafter. Fig.35 It can be seen that the driving coil 31 is switched 10 times and the power receiving coil 41 is switched 2 times.

[0345] Thus, according to the results of this experiment, it can be understood that the impedance reaches the matching state with a power reflectivity of less than 5% within 3 seconds, and the system startup is generally smooth. However, compared with the experimental results of Example 6, the time until the power reflectivity stabilizes at less than 5% in this experiment is longer, and Example 6 shows good responsiveness.

[0346] <Example 8>

[0347] An experiment (Example 8) was conducted. As in Example 4, when the wireless power supply system 1A is used, the coil spacing between the power transmission coil 32 and the power receiving coil 41 is fixed at 50 mm, and when the load resistance value in the load 8 is changed, the driving coil portion 31A to 31F of the driving coil 31 and the coil area 41A to 41D of the power receiving coil 41 are automatically switched to match the impedance. The switching of the driving coil 31 and the power receiving coil 41 in this experiment is performed in the same manner as in Example 5 using the third switching method. In addition, the power supply frequency is 150 kHz.

[0348] Experimental sequence

[0349] First, the driving coil 31 is set in the driving coil section 31C, and the receiving coil 41 is set in the coil area 42C. From this initial state, the load resistance is maintained at 50Ω for about 5 seconds, and then the load resistance is increased to 500Ω. The load resistance is then maintained at 500Ω for about 6 seconds, and then the load resistance is reduced to 50Ω again. The change in the power reflectivity in this experiment is shown in Figure 1. Fig.36 As shown. Again, Fig.37The switching history of the drive coil portions 31A to 31F of the drive coil 31 and the coil regions 41A to 41D of the power receiving coil 41 in this experiment is shown.

[0350] Experimental results

[0351] according to Fig.36 It can be seen that the power reflectivity rises to about 0.41 (41%) when the load resistance increases from 50Ω to 500Ω, but drops to below 0.05 (below 5%) in about 2 seconds and then maintains this state. It can also be seen that when the load resistance decreases from 500Ω to 50Ω, the power reflectivity rises to about 0.91 (91%), but drops to below 0.05 (below 5%) in about 4 seconds and then maintains this state.

[0352] Again, according to Fig.37 It can be seen that when the load resistance increases from 50Ω to 500Ω, the drive coil 31 switches twice and the power receiving coil switches twice. It can also be seen that when the load resistance decreases from 500Ω to 50Ω, the drive coil 31 switches 10 times and the power receiving coil switches 2 times.

[0353] Thus, according to the results of this experiment, regardless of whether the load resistance is increased or decreased, the impedance matching state in which the power reflection rate is reduced to 5% or less is achieved within 5 seconds, and for example, the load side impedance "Z0" fluctuates as the battery in the load 8 is charged. For example, it can be understood that even when the load side impedance "Z0" fluctuates as the battery in the load 8 is charged, the impedance matching can be smoothly performed.

[0354] <Example 9>

[0355] An experiment (Example 9) was conducted. As in Example 4, when the distance between the power transmission coil 32 and the power receiving coil 41 is continuously changed using the wireless power supply system 1A, the drive coil parts 31A to 31F of the drive coil 31 and the coil areas 41A to 41D of the power receiving coil 41 are automatically switched to match the impedance. The switching of the drive coil 31 and the power receiving coil 41 in this experiment is performed by the first switching method as in Example 4.

[0356] Experimental sequence

[0357] The object 2 to be powered is set as an unmanned guided vehicle (AGV) that can travel automatically, and the object 2 to be powered is equipped with a battery that can supply the required power for charging as a load 8. The receiving coil 41 carried on the object 2 to be powered is set as the coil area 42C, and the driving coil 31 carried on the power transmitting device 3 is set as the driving coil part 31B. From this initial state, the distance between the transmitting coil 32 and the receiving coil 41 is maintained at 150 mm for about 2 seconds, and then separated to 200 mm in about 1 second. Thereafter, the distance between the transmitting coil 32 and the receiving coil 41 is maintained at 200 mm for about 2 seconds, and then separated to 300 mm in about 1 second. Then, the distance between the transmitting coil 32 and the receiving coil 41 is maintained at 300 mm for about 2 seconds, and then approaches 150 mm in about 1 second. This series of sequences is repeated until the power in the battery (load 8) drops below the specified value and the unmanned guided vehicle (object 2 to be powered) stops. The change in power reflectivity in this experiment is shown in FIG. Fig.38 shown.

[0358] Experimental results

[0359] In this experiment, the object 2 to be powered stopped at 16 minutes and 10 seconds (970 seconds). Fig.38 It is clear that the power reflectivity changes periodically between about 0.07 (7%) and 0.40 (40%) as the object 2 moves. The average value of the power reflectivity until the object 2 stops is 0.132 (13.2%).

[0360] <Comparative Example 1>.

[0361] An experiment (Comparative Example 1) was conducted. In the same configuration as in Example 6, when the distance between the power transmission coil 32 and the power receiving coil 41 continuously changed, the driving coil 31 and the power receiving coil 41 were fixed without switching, and the power reflectivity until the unmanned transport vehicle (power supply object 2) stopped and the time until the power supply object 2 stopped were measured. The change of power reflectivity in this experiment is shown in FIG. Fig.39 shown.

[0362] Experimental results

[0363] In this experiment, the object 2 to be powered stopped at 14 minutes and 7 seconds (847 seconds). Fig.39 It is clear that the power reflectivity changes periodically between about 0.05 (5%) and 0.80 (80%) as the object 2 moves. The average value of the power reflectivity until the object 2 stops is 0.444 (44.4%).

[0364] <Comparative Example 2>

[0365] An experiment (Comparative Example 2) was conducted. In the same configuration as in Example 6, the unmanned transport vehicle (power supply object 2) equipped with the power receiving coil 41 and the battery (load 8) was not wirelessly powered, and the unmanned transport vehicle was driven only by the power charged by the battery, and the time until the unmanned transport vehicle stopped was measured.

[0366] Experimental results

[0367] In this experiment, the object 2 to be powered stopped at 8 minutes and 58 seconds (538 seconds).

[0368] Comparing the experimental results of Example 9 with Comparative Examples 1 and 2, the unmanned transport vehicle in Example 9 can travel 123 seconds longer than in Comparative Example 1, which is about 15% longer in operation time. In addition, compared with Comparative Example 2, the unmanned transport vehicle in Example 9 can travel 432 seconds longer, which is about 80% longer in operation time. That is, in Example 9, even if the object 2 to be powered is continuously moving, impedance matching can be performed quickly and power can be continuously supplied.

[0369] <Example 10>

[0370] An experiment (Example 10) was conducted. As in Example 4, when the distance between the power transmission coil 32 and the power receiving coil 41 is continuously and randomly changed using the wireless power supply system 1A, the drive coil parts 31A to 31F of the drive coil 31 and the coil areas 41A to 41D of the power receiving coil 41 are automatically switched to match the impedance. The switching of the drive coil 31 and the power receiving coil 41 in this experiment is performed by the first switching method as in Example 4.

[0371] Experimental sequence

[0372] The object 2 to be powered is set as an unmanned guided vehicle (AGV) that can travel automatically, and the object 2 to be powered is equipped with a battery that can supply the required power for charging as a load 8. A 900mm×900mm platform is arranged at a distance of 200mm from the power transmission device 3, and the object 2 to be powered moves randomly on the platform. The object 2 to be powered can move parallel to the platform, and can change its direction by rotating around a vertical rotation axis relative to the platform. The power receiving coil 41 carried on the object 2 to be powered is set as the coil area 42C, and the driving coil 31 carried by the power transmission device 3 is set as the driving coil part 31B. Starting from this initial state, the experiment is repeated until the object 2 to be powered starts to move, the power in the battery (load 8) drops below the specified value, and the unmanned guided vehicle (object 2 to be powered) stops. This series of experiments was conducted a total of 4 times. The changes in the power reflectivity in the 4 experiments are shown as follows. Figure 40 to Figure 43 shown.

[0373] Experimental results

[0374] The time until the object 2 to be powered stopped was measured in four experiments: 43 seconds, 46 seconds, 48 ​​seconds, and 43 seconds, with an average of 45 seconds. Figure 40 to Figure 43 The power reflectivity of Example 7 repeatedly shows peak values ​​and valley values, indicating that impedance matching and mismatching are repeated following the movement of the object 2 to be powered.

[0375] <Comparative Example 3>

[0376] Four experiments (Comparative Example 3) were conducted with the same configuration as in Example 7. When the distance between the power transmission coil 32 and the power receiving coil 41 was continuously and randomly changed, the power reflectivity was measured until the unmanned transport vehicle (power supply target 2) stopped without switching the driving coil 31 and the power receiving coil 41. The changes in the power reflectivity in the four experiments are shown in FIG. Figures 44 to 47 shown.

[0377] Experimental results

[0378] The time until the object 2 to be powered stopped was measured in four experiments: 36 seconds, 41 seconds, 33 seconds, and 33 seconds, with an average of 35.75 seconds. Figures 44 to 47 , the power reflectivity of Comparative Example 3 is above 0.8 (80%) most of the time, which indicates that the impedance matching cannot keep up with the movement of the unmanned transport vehicle.

[0379] <Comparative Example 4>

[0380] Four experiments (Comparative Example 4) were conducted with the same configuration as Example 7 to measure the time it takes for an unmanned transport vehicle (power supply object 2) equipped with a power receiving coil 41 and a battery (load 8) to stop when the unmanned transport vehicle runs solely on the power charged in the battery without wireless power supply.

[0381] Experimental results

[0382] The time until the object 2 to be powered stopped, measured in four experiments, was 33 seconds, 36 seconds, 34 seconds, and 28 seconds, with an average of 32.75 seconds.

[0383] Comparing the experimental results of Example 10, Comparative Examples 3 and 4, Example 10 can run for an average of 9.25 seconds longer than Comparative Example 3, extending the running time by about 12.6%. In addition, compared with Comparative Example 3, the impedance matching time of Example 10 is longer, thereby extending the running time of the unmanned transport vehicle. Moreover, compared with Comparative Example 4, Example 10 can run for 12.75 seconds longer, thereby extending the running time by about 13.7%.

[0384] In addition, there is no significant difference between the results of Comparative Examples 3 and 4. This is because, for the power transmission target object 2 that moves normally, in the case of a wireless power supply system that does not switch the drive coil parts 31A to 31F of the drive coil 31 and the coil areas 41A to 41D of the power receiving coil 41 as in Comparative Example 3, impedance matching cannot be achieved most of the time, so power can hardly be supplied to the power transmission target object 2. On the other hand, Example 10 achieves impedance matching even for the power supply target object 2 that moves normally, so power can be continuously supplied.

[0385] <Example 11>

[0386] An experiment (Example 11) was conducted. As in Example 4, when the distance between the power transmission coil 32 and the power receiving coil 41 continuously and randomly changes using the wireless power supply system 1A, only the drive coil parts 31A to 31F of the drive coil 31 are automatically switched to match the impedance. The switching of the drive coil 31 in this experiment is performed by the first switching method in the same manner as in Example 4.

[0387] Experimental sequence

[0388] First, the driving coil 31 is set in the driving coil portion 31C, and the receiving coil 41 is set in the coil area 41C. In this state, the distance between the power transmission coil 32 and the power reception coil 41 is maintained at 350 mm. After maintaining for about 6 seconds, the distance between the power transmission coil 32 and the power reception coil 41 is shortened to 250 mm in about 1 second. Then, the distance between the power transmission coil 32 and the power reception coil 41 is maintained at 250 mm for about 7 seconds, and then the distance between the power transmission coil 32 and the power reception coil 41 is shortened to 350 mm in about 1 second. Fig.48 The graph shows the change in power reflectivity and the history of switching of the drive coil units 31A to 31F of the drive coil 31 in the experiment.

[0389] Experimental results

[0390] according to Fig.48 It can be seen that when the distance between the power transmission coil 32 and the power reception coil 41 is reduced from 350 mm to 250 mm, the power reflection rate increases to about 0.20 (20%), but when the driving coil unit 31C ( Fig.48 3) in the sequence number 3) is switched to the drive coil section 31B ( Fig.48When the distance between the power transmission coil 32 and the power receiving coil 41 is increased from 250 mm to 350 mm, the power reflectivity rises to about 0.10 (10%), but by switching the drive coil section 31B to the drive coil section 31C, the power reflectivity drops to about 0.05 (less than 5%) in about 2 seconds, and maintains this state thereafter.

[0391] According to the results of this experiment, even if only the driving coil parts 31B and 31C are switched, if the distance between the power transmitting coil 32 and the power receiving coil 41 changes by about 100 mm, the power reflectivity will drop below 5% within 2 seconds, which can be said to be generally impedance matching.

[0392] Furthermore, the present invention may be modified in various ways other than those described above without departing from the spirit of the present invention, and the present invention may naturally also relate to such modified aspects.

[0393] Explanation of symbols

[0394] 1A, 1B, 1C, 1D, 1E: Wireless power supply system

[0395] 11: Wireless power receiving system

[0396] 2: Power supply object

[0397] 3: Power transmission device

[0398] 31: Driving coil

[0399] 31A~31H: Driving coil part

[0400] 31a-31c: Coil axis (of driving coil)

[0401] 32: Power transmission coil

[0402] 32a: Coil axis (of power transmission coil)

[0403] 33, 34: Capacitor

[0404] 35: Driving unit

[0405] 36: Power transmission department

[0406] 37: Reflected power detection unit

[0407] 38: Relative position measurement unit

[0408] 4: Power receiving device

[0409] 41: Receiving coil

[0410] 41A, 41B, 41C, 41D: Coil area

[0411] 42: Capacitor

[0412] 43: Receiving unit

[0413] 5: AC power supply

[0414] 5A: Power supply unit

[0415] 6: Rectification circuit

[0416] 61: Diode

[0417] 62: Capacitor

[0418] 7: DC-DC Converter

[0419] 8: Load

[0420] 9: Impedance matching mechanism

[0421] 91a~91f:Switch

[0422] 92: Controller

[0423] 93: Storage

[0424] 94: Control Department

[0425] 95a, 95b, 95c, 95d: MOSFET

[0426] 96: Measurement Department

[0427] IE: Input terminal.

Claims

1. A wireless power supply system, comprising: A power transmission device having a power transmission side resonance circuit including a power transmission coil; a power receiving device including a power receiving unit having a power receiving-side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and power received by the power receiving coil being supplied to the load; and A control device that controls the power receiving unit; The wireless power supply system transmits and receives power between the power transmission coil and the power receiving coil by means of magnetic field resonance. It is characterized in that The power receiving coil is configured so that a plurality of coil regions having different numbers of coil turns can be selected in accordance with connection positions of a plurality of terminals provided on the power receiving coil. The control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating a difference between a load-side impedance, which is an impedance of a circuit from an input end of the power transmitting device to a load side, and an input-side impedance, which is an impedance of a circuit from an input end of the power transmitting device to a power supply device side.

2. The wireless power supply system according to claim 1, characterized in that: The control device adjusts the inductance of the selected coil region and the capacitance of the capacitor arranged in series with the selected coil region by switching the plurality of terminals, thereby maintaining the magnetic field resonance between the power transmission coil and the power reception coil.

3. The wireless power supply system according to claim 1, characterized in that: The power transmission device further comprises a driving unit including a driving coil, wherein the driving coil is arranged in a manner capable of magnetic field coupling with the power transmission coil and transmits electric power to the power transmission coil by utilizing magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

4. The wireless power supply system according to claim 3, characterized in that: The power transmission device further includes a reflected power detection unit, which is arranged between the power supply device and the drive coil and is used to detect the reflected power of the drive coil. The control device controls the power receiving unit or the driving unit according to the magnitude of the reflected power detected by the reflected power detecting unit.

5. The wireless power supply system according to claim 3, characterized in that: The power receiving device further comprises a measuring unit for measuring a load current or a load voltage in the load. The control device controls the power receiving unit or the driving unit according to the value detected by the measuring unit.

6. The wireless power supply system according to claim 3, characterized in that: The wireless power supply system further includes a relative position measuring unit for measuring a relative position between the power transmission coil and the power reception coil. The control device controls the power receiving unit or the driving unit according to the value measured by the relative position measuring unit.

7. A wireless power supply system, comprising: A power supply device, the power supply device having an AC power source; A power transmission device, the input end of which is connected to the power supply device, and has a power transmission side resonance circuit including a power transmission coil; a power receiving device including a power receiving unit having a power receiving-side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and power received by the power receiving coil being supplied to the load; and A control device that controls the power receiving unit; The wireless power supply system transmits and receives power between the power transmission coil and the power receiving coil by means of magnetic field resonance. It is characterized in that The power receiving coil is configured so that a plurality of coil regions having different numbers of coil turns can be selected in accordance with connection positions of a plurality of terminals provided on the power receiving coil. The control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating a difference between a load-side impedance, which is an impedance of a circuit from an input terminal of the power transmitting device to a load side, and an input-side impedance, which is an impedance of a circuit from an input terminal of the power transmitting device to a power supply device side. The power transmission device further comprises a driving unit including a driving coil, wherein the driving coil is arranged in a manner capable of magnetic field coupling with the power transmission coil and transmits electric power to the power transmission coil by utilizing magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

8. The wireless power supply system according to claim 7, characterized in that: The power supply device further includes a reflected power detection unit, which is arranged between the AC power supply and the input terminal of the power transmission device and is used to detect reflected power from the power transmission device side. The control device controls the power receiving unit or the driving unit according to the magnitude of the reflected power detected by the reflected power detecting unit.

9. The wireless power supply system according to claim 7, characterized in that: The wireless power supply system further includes a reflected power detection unit, the reflected power detection unit having an input terminal of the power transmission device disposed therein and configured to detect reflected power from the drive coil side. The control device controls the power receiving unit or the driving unit according to the magnitude of the reflected power detected by the reflected power detecting unit.

10. The wireless power supply system according to claim 1, characterized in that: The power transmission device comprises: a driving unit including a driving coil, the driving coil being arranged in a manner capable of coupling with the magnetic field of the power transmission coil and transmitting power to the power transmission coil; and a reflected power detection unit, the reflected power detection unit being arranged between the power supply device and the driving coil and used to detect the reflected power of the driving coil. The control device selects the plurality of coil areas by switching the plurality of terminals in accordance with the power reflection rate or the power reflection coefficient calculated based on the reflected power, based on a previously stored correspondence relationship between the power reflection rate or the power reflection coefficient and the inductance of the power receiving coil.

11. The wireless power supply system according to claim 10, characterized in that: The above correspondence is obtained based on the relationship between the measured value of the load-side impedance, which is the impedance from the input end of the above power transmission device to the load-side circuit, and the above power reflection rate or power reflection coefficient, and the relationship between the theoretical value of the load-side impedance and the inductance of the above power receiving coil. The control device changes the inductance of the power receiving coil so that a theoretical value of the load-side impedance approaches an actually measured value of the load-side impedance calculated based on the power reflection rate or the power reflection coefficient.

12. The wireless power supply system according to claim 11, characterized in that: The control device changes the inductance of the power receiving coil again in such a manner that the theoretical value of the load side impedance approaches the actual measured value of the load side impedance when the power reflection rate or the power reflection coefficient calculated from the reflected power re-detected by the reflected power detection unit after the inductance of the power receiving coil changes is greater than a specified value.

13. The wireless power supply system according to claim 10, characterized in that: The driving coil transmits electric power to the power transmission coil by means of magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

14. The wireless power supply system according to claim 13, characterized in that: The control device switches the plurality of terminals to select the coil area of ​​the power receiving coil corresponding to the calculated power reflection rate or power reflection coefficient based on a previously stored correspondence relationship between the power reflection rate or power reflection coefficient calculated from the reflected power and the coil area of ​​the power receiving coil.

15. The wireless power supply system according to claim 14, characterized in that: The driving coil transmits electric power to the power transmission coil by means of magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

16. The wireless power supply system according to claim 1, characterized in that: The power transmission device comprises: a driving unit having a driving coil, the driving coil being arranged in a manner capable of coupling with the magnetic field of the power transmission coil and transmitting power to the power transmission coil; and a reflected power detection unit, the reflected power detection unit being arranged between the power supply device and the driving coil and used to detect the reflected power of the driving coil. When the power reflection coefficient calculated based on the reflected power is greater than a specified value, the control device switches the multiple coil areas by switching the multiple terminals, so that the inductance of the power receiving coil is one level larger than before the switching. When the power reflection coefficient calculated based on the reflected power is less than a specified value, the control device switches the multiple coil areas by switching the multiple terminals, so that the inductance of the power receiving coil is one level smaller than before the switching.

17. The wireless power supply system according to claim 16, characterized in that: The driving coil transmits electric power to the power transmission coil by means of magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

18. A wireless power supply system, comprising: A power transmission device, the power transmission device comprising: a power transmission side resonance circuit including a power transmission coil; a driving unit having a driving coil, the driving coil being arranged in a manner capable of coupling with the magnetic field of the power transmission coil and transmitting power to the power transmission coil; a reflected power detection unit, the reflected power detection unit being arranged between a power supply device and the driving coil and used to detect the reflected power of the driving coil, a power receiving device including a power receiving unit having a power receiving-side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and power received by the power receiving coil being supplied to the load; and A control device, the control device controls the driving unit; The wireless power supply system transmits and receives the power supplied by the power supply device between the power transmission coil and the power receiving coil by using magnetic field resonance. The driving coil is configured so that a plurality of driving coil parts can be selected, and electric power is transmitted to the power transmission coil by utilizing magnetic field resonance. The control device switches the multiple driving coil parts and changes the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil in accordance with the power reflection rate or the power reflection coefficient calculated from the reflected power, based on the correspondence between the power reflection rate or the power reflection coefficient stored in advance and the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

19. A wireless power receiving system, the wireless power receiving system receiving electric power transmitted by a magnetic field resonance method from a power transmitting device, the power transmitting device having a power transmitting side resonance circuit including a power transmitting coil, characterized in that: The wireless power receiving system includes a power receiving unit having a power receiving side resonance circuit including a power receiving coil, and the wireless power receiving system can be connected to a load, and the power received by the power receiving coil is supplied to the load; The power receiving coil is configured so that a plurality of coil regions having different numbers of coil turns can be selected in accordance with connection positions of a plurality of terminals provided on the power receiving coil. The control device for controlling the power receiving unit changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating a difference between a load-side impedance, which is an impedance of a circuit from the input end of the power transmitting device to the load side, and an input-side impedance, which is an impedance of a circuit from the input end of the power transmitting device to the power supply device side.

20. The wireless power receiving system according to claim 19, characterized in that: The control device can adjust the inductance of the selected coil region and the capacitance of the capacitor arranged in series with the selected coil region by switching the plurality of terminals, thereby maintaining the magnetic field resonance between the power transmission coil and the power reception coil.

21. A wireless power supply method, the wireless power supply method using a wireless power supply system, the wireless power supply system having: A power transmission device having a power transmission side resonance circuit including a power transmission coil; a power receiving device including a power receiving unit having a power receiving-side resonance circuit including a power receiving coil, the power receiving device being connectable to a load, and power received by the power receiving coil being supplied to the load; and A control device that controls the power receiving unit; The wireless power supply system transmits and receives power between the power transmission coil and the power receiving coil by means of magnetic field resonance. It is characterized in that The power receiving coil is configured so that a plurality of coil regions having different numbers of coil turns can be selected in accordance with connection positions of a plurality of terminals provided on the power receiving coil. The control device changes the inductance of the power receiving coil by switching the plurality of terminals, thereby alleviating a difference between a load-side impedance, which is an impedance of a circuit from an input end of the power transmitting device to a load side, and an input-side impedance, which is an impedance of a circuit from an input end of the power transmitting device to a power supply device side.

22. The wireless power supply method according to claim 21, characterized in that: The power transmission device further comprises a driving unit including a driving coil, wherein the driving coil is arranged in a manner capable of magnetic field coupling with the power transmission coil and transmits electric power to the power transmission coil by utilizing magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

23. The wireless power supply method according to claim 22, characterized in that: The load side impedance is adjusted by the control device by switching the terminals of the power receiving coil to perform rough adjustment, and then the drive unit is controlled to perform fine adjustment.

24. The wireless power supply method according to claim 22, characterized in that: The power transmission device comprises: a driving unit having a driving coil, the driving coil being arranged in a manner capable of magnetic field coupling with the power transmission coil and transmitting electric power to the power transmission coil; and a reflected power detection unit, the reflected power detection unit being arranged between the power supply device and the driving coil and used for detecting the reflected power of the driving coil, The control device selects a plurality of coil areas by switching the plurality of terminals in accordance with the power reflection rate or the power reflection coefficient calculated from the reflected power, based on a pre-stored correspondence relationship between the power reflection rate or the power reflection coefficient and the impedance of the power receiving coil.

25. The wireless power supply method according to claim 24, characterized in that: The driving coil transmits electric power to the power transmission coil by means of magnetic field resonance. The control device controls the driving unit so as to change the coupling strength of the magnetic field coupling between the power transmission coil and the driving coil.

26. The wireless power supply method according to claim 25, characterized in that: The load side impedance is adjusted by the control device by switching the terminals of the power receiving coil to perform rough adjustment, and then fine adjustment is performed by controlling the drive unit.

27. The wireless power supply method according to claim 24, characterized in that: The power receiving device is configured to be movable. The power transmission device transmits the electric power supplied from the power supply device to the power receiving coil during the movement of the power receiving device.

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