Power supply system having position detection function

Abstract

To provide means capable of suppressing the occurrence of electromagnetic interference in a free position power supply system using an electric field coupling method.SOLUTION: A power supply system includes, at least: a power transmission module 10 that is connected to a high-frequency power supply 50 and includes at least a plurality of power transmission side electrode parts 11; a power reception module 20 that is connected to a load 60 and includes at least a power reception side electrode part 21; a position detection unit 30 that can detect the position of the power reception module 20 on the power transmission module 10; and a power transmission control unit 40 that selects the power transmission side electrode part 11 to perform wireless power transmission from among the plurality of power transmission side electrode parts 11 based on a detection result of the position detection unit 30. At the time of use, among all the power transmission side electrode parts 11 constituting the power transmission module 10, power transmission side electrode parts 11 not facing the power reception side electrode part 21 are not subjected to power transmission from the high-frequency power supply 50. Thus, it is possible to suppress the occurrence of radiation noise and to suppress the occurrence of electromagnetic interference.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply system that enables power supply at a free position by an electric field coupling method, and more particularly to a power supply system having a position detection function of an electric device on the power receiving side to be powered.

Background Art

[0002] An electric field coupling method (FIG. 7), known as a type of wireless power supply, is a method of supplying power by using a capacitor formed between electrodes when a pair of electrode sets are respectively installed on the power transmitting side and the power receiving side and the electrodes on the power transmitting side and the power receiving side are close to each other. As a power supply system using this electric field coupling method, for example, a charging system described in Patent Document 1 below is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As an example of the utilization of a power supply system using the electric field coupling method, a power transmission module is incorporated into furniture such as desks and cabinets installed on the floors, walls, roads, and structures in a facility, and a power reception module is incorporated into various electric devices (including batteries, the same applies hereinafter) used in the structure to enable power supply at a free position. However, non-contact power supply using the electric field coupling method has a higher power transmission frequency than the magnetic field coupling method, and since the electrode plate used as an electrode constitutes a flat antenna, electromagnetic wave radiation noise is likely to occur. In addition, at locations where there is no electrode plate on the power receiving side that serves as the counter electrode, radiation noise is likely to be emitted from the electrode plate on the power transmitting side. Compared with the magnetic field coupling method in which power supply is performed only at the coil facing portion, there are concerns such as the occurrence of electromagnetic interference (EMI) and the influence on the human body by unnecessary electromagnetic waves.

[0005] Therefore, one of the objectives of the present invention is to provide a means capable of suppressing the occurrence of electromagnetic interference as much as possible in a power supply system that enables power supply in a free position by an electric field coupling method.

Means for Solving the Problem

[0006] The invention of the present application made to solve the above problems is a power supply system that performs wireless power transmission in a free position by an electric field coupling method, and includes a power transmission module that is connected to a high-frequency power source and has at least a plurality of power transmission side electrode portions, a power reception module that is connected to a load and has at least a power reception side electrode portion, a position detection unit that can detect the position of the power reception module on the power transmission module, and a power transmission control unit that selects a power transmission side electrode portion for performing wireless power transmission from among the plurality of power transmission side electrode portions based on the detection result by the position detection unit.

[0007] According to this configuration, among all the power transmission side electrode portions constituting the power transmission module, wireless power transmission is performed between the power transmission side electrode portion at the location where the power reception module is placed and the power reception side electrode portion. Since power transmission from the high-frequency power source is not performed on the power transmission side electrode portion where the power reception side electrode portion is not arranged opposite, the generation of radiation noise can be suppressed, and the occurrence of electromagnetic interference can be suppressed.

Effects of the Invention

[0008] According to the present invention, in a power supply system that enables power supply in a free position by an electric field coupling method, the occurrence of electromagnetic interference can be suppressed as much as possible.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, the details of the power supply system according to the present invention will be described. Note that in each figure, the illustration of elements for which detailed description is not provided may be omitted.

[0011] <1> Overall Configuration (Fig. 1) The power supply system according to the present invention (hereinafter also referred to as this system) is a system for performing wireless power transmission in a free position by an electric field coupling method, and includes at least a power transmission module 10, a power reception module 20, a position detection unit 30, and a power transmission control unit 40. Note that in Fig. 1, the illustration of the power reception side matching, rectification, charge control unit, etc. is omitted. In this system, when the power transmission module 10 connected to the high-frequency power supply 50 and the power reception module 20 connected to an electronic device (including a battery) having a load 60 are arranged to face each other, while the position detection unit 30 detects the position of the power reception module 20, based on this detection result, the power transmission control unit 40 selects a power transmission side electrode unit 11 that performs wireless power transmission from among a plurality of power transmission side electrode units 11 constituting the power transmission module 10, thereby realizing power supply (including "charging", the same applies hereinafter) to the electronic device by wireless power transmission using the electric field coupling method. The details of each part will be described below.

[0012] <2> Power transmission module (Fig. 1) The power transmission module 10 is a module that constitutes a power transmission side circuit by an electric field coupling method. The power transmission side module has a plurality of power transmission side electrode portions 11 that are part of the electrodes constituting the capacitor in the wireless power supply circuit by the electric field coupling method. In the present invention, the shape, number, arrangement form, etc. of each power transmission side electrode portion 11 are not particularly limited. Each power transmission side electrode portion 11 is individually connected to the high-frequency power supply 50, and is wired so that the connection to one pole or the other pole of the high-frequency power supply 50 can be switched by the power transmission control unit 40 described later, and the ON / OFF of power transmission from the high-frequency power supply 50 can be switched.

[0013] <3> Power reception module (Fig. 1) The power reception module 20 is a module that constitutes a power reception side circuit by an electric field coupling method. The power reception side module has at least one or more power reception side electrode portions 21 that are part of the electrodes constituting the capacitor in the wireless power supply circuit by the electric field coupling method. In the present invention, the shape, number, arrangement form, etc. of the power transmission side electrode portion 11 are not particularly limited. Each power reception side electrode portion 21 is individually connected to the high-frequency power supply 50, and is wired so that the connection to one pole or the other pole of the high-frequency power supply 50 can be switched, and the ON / OFF of power transmission from the high-frequency power supply 50 can be switched.

[0014] <4> Position detection unit (Fig. 1) The position detection unit 30 is a member for detecting the position of the power reception module 20 on the power transmission module 10. When transmitting the detection information of the position of the power reception module 20 from the position detection unit 30 to the power transmission control unit 40, a band that does not interfere with the power transmission frequency related to wireless power transmission is used. In the present invention, the method for detecting the position of the power receiving module 20 by the position detection unit 30 is not particularly limited, and for example, the following methods can be adopted.

[0015] <4.1>Detection by a positioning unit A method of incorporating a positioning unit into the power transmission module 10 and / or the power receiving module 20 and detecting the position of the power receiving module 20 from the positioning result obtained by this positioning unit. In the present invention, the positioning method in the positioning unit is not particularly limited, and it may be appropriately selected from those that do not malfunction in the wireless power supply environment according to this system. As technologies that can be selected as the positioning unit, those using the detection of RFID (Radio Frequency Identification) tags, those using image recognition, those using various sensors (proximity sensors, photoelectric sensors, time sensors, eddy current displacement sensors, contact displacement sensors, ultrasonic sensors, etc.), those using various positioning technologies (UWB (Ultra-Wide Band) positioning, BLE (Bluetooth Low Energy) positioning, wireless LAN positioning, etc.), etc. can be considered. And by appropriately adjusting the number of arrangements and the arrangement intervals of the positioning units, the accuracy of position detection can be adjusted.

[0016] <4.2>Detection by change in capacitance A method of incorporating a measurement unit capable of measuring the value of the capacitance in a capacitor composed of the power transmission side electrode part 11 provided in the power transmission module 10 and the power reception side electrode part 21 provided in the power reception module 20, and detecting the position of the power reception module 20 from the change in this measured value.

[0017] <4.3>Detection by change in load A method of incorporating a sensor (such as a load cell) capable of measuring the load into the power transmission module 10 and detecting the position of the power reception module 20 from the change in the measured value by the sensor.

[0018] <4.4>Detection by proximity sensor A method for detecting the position of the power receiving module 20 by detecting the approach of the power receiving module 20 with a proximity sensor incorporated in the power transmission module 10.

[0019] <5>Power transmission control unit (FIG. 1) The power transmission control unit 40 is a member for selecting a power transmission side electrode unit 11 that performs wireless power transmission from among a plurality of power transmission side electrode units 11 based on the detection result by the position detection unit 30. In the present invention, the method for selecting the power transmission side electrode unit 11 to be energized from the detection result by the position detection unit 30 is not particularly limited, and an appropriate and preferable method may be designed according to various detection methods exemplified in <4> above. For example, when the center coordinates of the power receiving module 20 can be detected using the positioning unit exemplified in <4.1>, only the power transmission side electrode unit 11 facing the power receiving side electrode unit 21 in the power receiving module 20 estimated from the center coordinates may be selected. Also, when the outer shape of the entire power receiving module 20 can be grasped by, for example, the change in capacitance, the change in load, or the detection by a proximity sensor exemplified in <4.2> to <4.4>, the power transmission side electrode unit 11 estimated to face the surface related to this outer shape may be selected as the power transmission side electrode unit 11 that performs wireless power transmission.

[0020] Next, an application example of this system will be described.

Example

[0021] <1>Overall configuration (FIG. 2) The power supply system according to this embodiment includes a power transmission module 10 and a power receiving module 20 as shown in FIG. 2, and when the modules are brought into contact so as to be opposed to each other, wireless power transmission by electric field coupling is performed by a high frequency flowing from the high frequency power supply 50. As a result, power supply (including charging. The same applies hereinafter) to an electronic device (including a battery) having a load 60 in which the power receiving module 20 is incorporated is realized. Details of each part will be described below.

[0022] <2>Power transmission side electrode part (Fig. 2) The power transmission side electrode part 11 is provided in the power transmission module 10 and is a member that forms part of the electrode constituting the capacitor in the wireless power feeding circuit by the electric field coupling method. In this embodiment, 49 power transmission side electrode parts 11, which consist of 7 rows and 7 columns (A1 to G7) and are independently connected to the high-frequency power supply 50, are provided. In this embodiment, the position detection unit 30 and the power transmission control unit 40 cause an arbitrary power transmission side electrode part 11 among the 49 power transmission side electrode parts 11 to function as part of the electrode constituting the capacitor in the wireless power feeding circuit by the electric field coupling method.

[0023] <3>Power reception side electrode part (Fig. 2) The power reception side electrode part 21 is provided in the power reception module 20 and is a member that forms the other electrode constituting the capacitor in the wireless power feeding circuit by the electric field coupling method. In this embodiment, two power reception side electrode parts 21 are provided in the power reception module 20. Among them, one power reception side electrode part 21 is connected to one pole of the load 60, and the other power reception side electrode part 21 is connected to the other pole of the load 60. In Fig. 2, the matching circuit and the rectifying circuit are not shown. However, since one matching circuit is sufficient as in the conventional case, it contributes to weight reduction compared to the multi-power reception electrode method.

[0024] <4>Position detection unit (not shown in Fig. 2) The position detection unit 30 is a member for detecting the position of the power reception module 20 on the power transmission module 10. In this embodiment, an RFID reader is incorporated on the power reception module 20 side as the position detection unit 30, and RFID tags are embedded at a plurality of predetermined positions on the power transmission module 10 side. Then, by associating the embedding position with the identification number of the RFID tag in advance, when the power reception module 20 is placed at an arbitrary position on the power transmission module 10, the position of the power reception module 20 can be detected from the identification number of the read RFID tag.

[0025] <5>Usage image (Fig. 2) Next, the usage image of the power supply system according to this embodiment will be described.

[0026] <5.1> Image of position detection (Fig. 2) For example, when the power transmission module 10 and the power reception module 20 are in the positional relationship shown in Fig. 2, the position detection unit 30 reads the RFID tag to obtain position information, and based on the position information, the power transmission control unit 40 selects C3, C4, and C5 among the power transmission side electrode parts 11 constituting the power transmission side module as the power transmission side electrode parts 11 related to one electrode group, and selects E3, E4, and E5 as the power transmission side electrode parts 11 related to the other electrode group.

[0027] <5.2> Equivalent circuit (Fig. 3) Fig. 3 is an equivalent circuit showing the outline of the wireless power supply circuit realized by the power supply system according to this embodiment. The equivalent circuit shown in Fig. 3 constitutes a parallel resonance type power transmission circuit, and is composed of a high-frequency power supply 50, a transformer composed of an inductor and a variable capacitor, a power transmission control unit 40 equipped with an electrode switching switch, a power transmission side electrode part 11, a power reception side electrode part 21, a power reception side resonance circuit, and a load 60. Based on the positioning information obtained from the position detection unit 30, the power transmission control unit 40 switches the ON / OFF of the opposing power supply circuit. At this time, the power reception side electrode part 21 switches the circuit to be switched according to the information of whether it is the electrode of (a) or the electrode of (b). The circuit switching can be performed by a relay or a semiconductor (such as a bipolar transistor or a MOSFET). Also, since the capacitance changes according to the number of electrodes that are ON, the variable capacitor is automatically adjusted to resonate. Since the capacitance is determined by the number, it may be switched by using a capacitor array.

[0028] <6> Parentheses According to the power supply system according to this embodiment with the above-described configuration, when the power transmission module 10 and the power reception module 20 are arranged opposite to each other, among all the power transmission side electrode portions 11 constituting the power transmission module 10, only the power transmission side electrode portion 11 at the location where the power reception module 20 is arranged opposite is selected as the power transmission side electrode portion 11 to be used for wireless power transmission by the position detection unit 30 and the power transmission control unit 40. Therefore, while realizing wireless power supply in the free position, since power transmission from the high-frequency power supply 50 is not performed on the power transmission side electrode portion 11 where the power reception side electrode portion 21 is not arranged opposite, generation of radiation noise can be suppressed, generation of electromagnetic interference (EMI) can be suppressed, and concerns such as the influence on the human body by unnecessary electromagnetic waves are eliminated.

Embodiment

[0029] <1>Overall Configuration (Figs. 4 and 5) Next, Embodiment 2 according to this system will be described. In the configuration according to Embodiment 1 (Fig. 3), two combinations of power transmission side electrodes and power reception side electrodes (electrode sets) were provided on the circuit (one electrode set, the other electrode set). In the configuration according to this embodiment (Figs. 4 and 5), while replacing the other electrode set with direct wiring by the contact between the grounding portion 13 provided on the power transmission module 10 and the conductive portion 23 provided on the power reception module 20, the protective grounding on the power reception side is ensured by the ground 70 provided in the power transmission side circuit, and seemingly, wireless power supply is executed with one electrode set. Details of the members newly added in Embodiment 2 will be described below.

[0030] <2>Grounding Portion (Figs. 4 and 5) The grounding portion 13 is a member provided on the power transmission module 10 for connection to the ground 70. The grounding portion 13 is composed of a conductive member. One end is connected to both the other pole of the high-frequency power supply 50 and the ground 70, and the other end side is exposed on the surface side of the power transmission module 10 facing the power reception module 20.

[0031] <2.1>Regarding the shape etc. of the grounding part In the present invention, the grounding part 13 can adopt any shape, structure, etc. as long as it can make contact and conduct electricity with the conductive part 23 provided in the power receiving module 20 and has a space capable of inducing electric charges in the power transmission side electrode part 11 and the power receiving side electrode part 21. For example, a linear or strip-shaped conductive member can be arranged with a gap in one direction, arranged in a grid pattern in the vertical and horizontal directions, arranged in a spiral shape, etc., to provide a mesh opening part partitioned by the conductive member, or a flat plate-shaped conductive member can be punched to provide holes or slits, or the above-described modes can be appropriately combined. In this embodiment, the grounding part 13 is configured in a grid pattern.

[0032] <2.2>Regarding the opposing surface of the power transmission module In the present invention, regardless of the unevenness of the opposing surface of the power transmission module 10 having the grounding part 13, in the installation location of the power supply system according to the present invention, in order not to become an obstacle to human passage, object movement, cleaning work, etc., while exposing the grounding part 13 to the opposing surface side, it is preferable to configure the opposing surface to be smooth. As a method for realizing the above configuration, there are a method of arranging the grounding part 13 to be embedded in the power transmission side insulating part 12 so that their surface positions are aligned, a method of punching the grounding part 13 and using a flat plate-shaped conductive member that maintains smoothness as much as possible, etc. Also, the mesh opening part partitioned by the conductive member constituting the grounding part 13 may be filled with an insulator to make the opposing surface of the power transmission module 10 flush.

[0033] <3>Conductive part (FIG. 4, FIG. 5) The conductive part 23 is a member provided in the power receiving module 20 for contacting the grounding part 13 provided in the power transmission module 10 when receiving wireless power supply from the power transmission module 10. The conductive part 23 can be composed of a conductive member, one end is connected to the other pole of the load 60, and the other end side is exposed on the opposing surface side of the power receiving module 20.

[0034] <3.1>Regarding the shape, etc. of the conductive part In the present invention, the conductive part 23 can adopt any shape, structure, etc. as long as it can make contact and conduct electricity with the grounding part 13 provided in the power transmission module 10 and has a space capable of inducing charges in the power transmission side electrode part 11 and the power reception side electrode part 21. For example, a linear or strip-shaped conductive member is arranged with a gap in one direction, arranged in a grid pattern in the vertical and horizontal directions, arranged in a spiral shape, etc., to provide a mesh opening part partitioned by the conductive member, or a flat plate-shaped conductive member is punched to provide holes or slits, or the above-mentioned modes are appropriately combined, etc. On the opposing surface of the power reception module 20 with respect to the power transmission module 10, the power reception side insulating part 22 and the location where the conductive part 23 can be visually recognized are configured to be mixed. Note that the layout, separation length, etc. of each conductive member may be appropriately designed in a preferable mode in consideration of the structure of the grounding part 13 described above. In this embodiment, similar to the grounding part 13, the conductive part 23 is configured in a grid pattern.

[0035] <3.2>Regarding the opposing surface of the power reception module In the present invention, regardless of the unevenness of the opposing surface of the power reception module 20 having the conductive part 23, from the viewpoints of installation stability during power supply, etc., similar to the grounding part 13, the opposing surface of the power reception module 20 may be configured to be smooth.

[0036] <4>Power transmission side insulating part (Fig. 5) The power transmission side insulating part 12 is a member provided in the power transmission module 10 for electrically insulating the power transmission side electrode part 11 from the outside of the power transmission module 10. The power transmission side insulating part 12 may be made of any member as long as it has electrical insulation properties and can cover the power transmission side electrode part 11, and insulating materials in the form of sheets, films, or other arbitrary shapes can be used.

[0037] <5>Power reception side insulating part (Fig. 5) The power receiving side insulating portion 22 is provided in the power receiving module 20 and is a member for electrically insulating the power receiving side electrode portion 21 from the outside of the power receiving module 20. The power receiving side insulating portion 22 may be made of any member as long as it has electrical insulation properties and can cover the power receiving side electrode portion 21, and insulating materials in the form of sheets, films, or any other arbitrary shape can be used.

[0038] <6>Equivalent circuit (Fig. 6) Fig. 6 is an equivalent circuit of a wireless power feeding circuit realized by the power feeding system according to this embodiment. The equivalent circuit shown in Fig. 6 constitutes a parallel resonance type power transmission circuit, and includes a high-frequency power source 50, a transformer composed of inductances, a transformer composed of inductances and a variable capacitor, a power transmission control unit 40 provided with an electrode switching switch, a power transmission side electrode portion 11, a power receiving side electrode portion 21, a power receiving side resonance circuit, and a load 60, and further includes a ground 70. Based on the positioning information obtained from the position detection unit 30, the power transmission control unit 40 switches the ON / OFF of the opposing power source circuit. The circuit switching is performed by a relay, a semiconductor (such as a bipolar transistor or a MOSFET). Also, since the capacitance changes according to the number of electrodes that are ON, the variable capacitor is automatically adjusted to resonate. Since the capacitance is determined by the number, it may be a capacitor array and switched.

[0039] Power transmission is possible even without using a resonance type in the power transmission circuit. However, in the present invention, since a contact portion A where the grounding portion 13 and the conductive portion 23 are in contact is formed, the gap between the power transmission side electrode portion 11 and the power receiving side electrode portion 21 is kept constant, so power transmission in a resonance type is more excellent in transmission efficiency. Similar to Fig. 2, in Fig. 6, the matching circuit and the rectifying circuit are not shown, and since one matching circuit is sufficient as in the prior art, it contributes to weight reduction compared to the multi-electrode method. When the power transmission module 10 and the power receiving module 20 are in the positional relationship shown in Fig. 4, the power transmission side electrode portion 11 shown in Fig. 6 will have C3~C5, D3~D5, and E3~E5 selected.

[0040] <7> Small brackets According to the power supply system according to this embodiment, when the power transmission module 10 and the power reception module 20 are arranged opposite to each other, with the grounding portion 13 and the conductive portion 23 in contact to ensure the protective grounding on the load 60 side, wireless power transmission is performed between the power transmission side electrode portion 11 selected by the position detection portion 30 and the power transmission control portion 40 and the power reception side electrode portion 21. Therefore, in addition to the effects obtained by the configuration according to Embodiment 1, for the electrical equipment incorporating the power reception module 20, there is no need to separately provide a cable for grounding, there are no restrictions on power supply in the free position, and furthermore, it is possible to obtain the effect that the passage of people and the movement of objects due to the grounding cable are not hindered. In addition, in the configuration according to Embodiment 1, the power transmission side electrode portion 11 requires a circuit configuration to realize two-pole switching of being selected as a part of one electrode set or being selected as a part of the other electrode set. In contrast, in the configuration according to Embodiment 2, since the other electrode set is omitted, a circuit configuration that simply switches the ON / OFF of power transmission when selected as a part of only one electrode set is sufficient, so the circuit configuration can be made simpler.

Explanation of reference numerals

[0041] 10: Power transmission module 11: Power transmission side electrode portion 12: Power transmission side insulating portion 13: Grounding portion 20: Power reception module 21: Power reception side electrode portion 22: Power reception side insulating portion 23: Conductive portion 30: Position detection portion 40: Power transmission control portion 50: High-frequency power supply 60: Load 70: Ground A: Contact portion

Claims

1. A power supply system for wireless power transmission in a free position by an electric field coupling method, connected to a high-frequency power source and having at least a plurality of power transmission side electrode portions, a power transmission module, connected to a load and having at least a power reception side electrode portion, a power reception module, a position detection unit capable of detecting the position of the power reception module on the power transmission module, a power transmission control unit that selects a power transmission side electrode portion for performing wireless power transmission from among the plurality of power transmission side electrode portions based on a detection result by the position detection unit, characterized by comprising at least, a power supply system.

2. The power transmission module, has at least the plurality of power transmission side electrode portions, a power transmission side insulating portion, and a grounding portion arranged in order toward the side facing the power reception module, The power reception module, has at least the power reception side electrode portion, a power reception side insulating portion, and a conductive portion arranged in order toward the side facing the power transmission module, One pole of the high-frequency power source is connected to the power transmission side electrode portion selected by the power transmission control unit, and the other pole is connected to the grounding portion and grounded, One pole of the load is connected to the power reception side electrode portion, and the other pole is connected to the conductive portion, When wireless power transmission is performed between the power transmission side electrode portion selected by the power transmission control unit and the power reception side electrode portion, the grounding portion and the conductive portion are in contact with each other to ensure protective grounding on the load side, The power supply system according to claim 1.

Images