Wireless power transmission system and control method for wireless power transmission system

Abstract

The objective is to miniaturize and improve the efficiency of wireless power transmission systems. [Solution] A wireless power transmission system comprising: a plurality of receiving antennas that move in a predetermined direction; a receiving unit having a plurality of receiving circuits connected to each of the receiving antennas; a plurality of transmitting antennas that face each of the plurality of receiving antennas and are electromagnetically coupled; and a transmitting unit having a plurality of transmitting circuits connected to each of the plurality of transmitting antennas, wherein the plurality of transmitting antennas move such that their relative position to the plurality of receiving antennas is substantially constant.

Description

[Technical Field]

[0001] The present invention relates to a wireless power transmission system and a method for controlling a wireless power transmission system. [Background technology]

[0002] There are systems that supply power to motors for driving. For example, in a semiconductor exposure apparatus, a coarse-movement stage for moving the wafer to the exposure position is mounted on a fine-movement stage for making minute movements of the wafer, and multiple motors are mounted to drive the fine-movement stage. Power to drive these multiple motors is supplied by a power supply cable. Since this cable moves in conjunction with the movement of the coarse-movement stage, the tension of the cable affects the positioning accuracy of the stage. To eliminate this cable, Patent Document 1 describes a configuration in which power for motor driving is transmitted wirelessly. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-54847 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The wireless power transmission system disclosed in Patent Document 1 consists of a transmitting antenna whose longest side is greater than the range of motion of the coarse stage, and a receiving antenna that moves together with the coarse stage. However, the size of the transmitting antenna is large, making it difficult to place it near the coarse stage due to size constraints, in order to supply power to multiple motors. Furthermore, the large size ratio between the transmitting and receiving antennas reduces the coupling coefficient, resulting in a deterioration of power transmission efficiency. The present invention aims to provide a wireless power transmission system that is compact and highly efficient. [Means for solving the problem]

[0005] One aspect of the present invention is a wireless power transmission system comprising: a plurality of receiving antennas that move in a predetermined direction; a receiving unit having a plurality of receiving circuits connected to each of the receiving antennas; a plurality of transmitting antennas that face each of the plurality of receiving antennas and are electromagnetically coupled; and a transmitting unit having a plurality of transmitting circuits connected to each of the plurality of transmitting antennas, wherein the plurality of transmitting antennas move such that their relative positions with respect to the plurality of receiving antennas remain substantially constant. [Effects of the Invention]

[0006] According to the present invention, by providing the means described above, it is possible to provide a wireless power transmission system that is smaller in size and more efficient than conventional systems. [Brief explanation of the drawing]

[0007] [Figure 1] This is an example of a configuration diagram of the wireless power transmission system of the present invention. [Figure 2] This is an example of a conceptual diagram of a conventional wireless power transmission system. [Figure 3] This is an example of an image diagram of a wireless power transmission system according to the first embodiment of the present invention. [Figure 4] This figure shows the equivalent circuit of the electromagnetic field coupling section in a wireless power transmission system according to a first embodiment of the present invention. [Figure 5] This is a diagram of a simulation model of a wireless power transmission system according to a first embodiment of the present invention. [Figure 6] This is a simulation result of a wireless power transmission system according to the first embodiment of the present invention. [Figure 7] This is an example of an image diagram of the power transmission section of a wireless power transmission system according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0008] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings.

[0009] In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, thus omitting redundant explanations.

[0010] (First embodiment) A first embodiment of the present invention is described below. The wireless power transmission system according to this embodiment utilizes at least one of the technologies known as electromagnetic induction and magnetic resonance, which transmit power using a magnetic field, or both power and a magnetic field, to supply power to a driven object such as a motor.

[0011] Furthermore, in this embodiment, we will focus on the case where the wireless power transmission system is applied to a semiconductor exposure apparatus and describe the features of the wireless power transmission system, but this does not necessarily limit the application of the wireless power transmission system according to this embodiment. Specifically, the wireless power transmission system according to this embodiment can be applied to any device that drives multiple drive targets, such as motors and control circuits, and transmits power to these drive targets wirelessly. In particular, among the above-mentioned devices, devices that individually control the power supply to each of the multiple drive targets have a high affinity with the wireless power transmission system according to this embodiment. As a more specific example, the wireless power transmission system according to this embodiment can also be applied to inkjet printers, robotic devices, automated guided vehicles (AGVs), etc.

[0012] (Outline of the system configuration) Referring to FIG. 1, an example of the schematic configuration of the wireless power transmission system according to this embodiment will be described. In the example shown in FIG. 1, the wireless power transmission system 300 drives a plurality of motors 400 and individually supplies power to each motor 400 via a wireless transmission path. The motor 400 corresponds to, for example, an individual motor for moving a stage in a semiconductor exposure apparatus, and each can be independently driven. Although about 10 motors are used in a semiconductor exposure apparatus, in the example shown in FIG. 1, a configuration for driving four motors 400 is extracted and illustrated. The wireless power transmission system 300 includes a power transmission unit 100 and a power reception unit 200. In this embodiment, the entire wireless power transmission system 300 is mounted in one device, and the power transmission unit 100 and the power reception unit 200 move in parallel with the coarse movement stage.

[0013] However, the implementation of the wireless power transmission system 300 is not limited to this and can be adapted to a system that moves in parallel in a predetermined direction.

[0014] The power transmission unit 100 includes four power transmission antennas 101, a transmission coupler 102, a controller 103, a power source 104, a transmission circuit 105, and four SW (Switch) circuits 106 that function as power transmission circuits.

[0015] The power reception unit 200 includes four power reception antennas 201, a reception coupler 202, a reception circuit 203, four power reception circuits 204, a gate drive circuit 205, and four motor drive circuits 206. There is no physical connection between the power transmission unit 100 and the power reception unit 200, and a power supply signal for supplying power is transmitted non-contact between each power transmission antenna 101 and each power reception antenna 201. Therefore, each of the power transmission antenna 101 and the power reception antenna 201 may include, for example, a coil-shaped antenna.

[0016] The power source 104 is a power source for driving the motor 400. Based on the control from the controller 103, the power source 104 applies a power supply voltage related to the supply of the power supply signal to the motor 400 to each SW circuit 106.

[0017] The controller 103 controls the operation of the power supply 104 based on various conditions. For example, the controller 103 monitors the state of each motor 400 (e.g., the position and orientation of the stage accompanying the driving of the motor 400, etc.) based on the detection results of various sensors such as an optical sensor, and may control the operation related to the application of the power supply voltage by the power supply 104 according to the monitoring results.

[0018] As an example of the control of the operation related to the application of the power supply voltage, there are control of the output voltage amplitude value for determining the thrust of the motor 400, control of the motor applied voltage code for determining the direction in which the motor 400 moves, and the like.

[0019] Information regarding the output voltage amplitude value is notified to the power supply 104 by the controller 103 outputting a control signal to the power supply 104. That is, the power supply 104 controls the output voltage amplitude value of the power supply voltage to be the specified value based on the control signal output from the controller 103.

[0020] Information regarding the motor applied voltage code is notified by the controller 103 transmitting a control signal to the gate drive circuit 205 via the transmission coupler 102 and the reception coupler 202. The gate drive circuit 205 reverses the rectification operation of the motor drive circuit 206 by 180° based on the control signal transmitted from the controller 103, thereby reversing the motor applied voltage code from positive to negative or from negative to positive.

[0021] Figure 2 shows an example of a configuration diagram for transmitting power to a motor using a conventional wireless power transmission system. It includes a fine-motion stage 001, a coarse-motion stage 002, a rail 003, a wafer 004, four transmitting antennas 101, and four receiving antennas 201. The longer side of the transmitting antenna 101 is longer than the range of motion of the coarse-motion stage 002 and is mounted along the rail 003. The motor has multiple motors to move the fine-motion stage 001, and in order to supply power to each of them, power can be transmitted to multiple locations by making the transmitting antennas 101 and receiving antennas 200 into a multilayer structure, as shown in Figure 2. However, there are placement constraints near the stage, making it difficult to place multilayer antennas. Also, because the ratio of the transmitting and receiving antenna lengths is large, the coupling coefficient decreases, and the power transmission efficiency deteriorates. Therefore, in this embodiment, the configuration of a wireless power transmission system that is compact and has high power transmission efficiency will be described using Figure 3.

[0022] Figure 3(a) is an example of a configuration diagram of a system for wirelessly transmitting power to a motor in the first embodiment. It includes a fine-motion stage 001, a coarse-motion stage 002, a rail 003, a wafer 004, a cable 005, four transmitting antennas 101, a case 306, and four receiving antennas 201. Note that the transmitting coupler 102, controller 103, power supply 104, transmitting circuit 105, four SW (Switch) circuits 106 that function as a power transmission circuit, as well as the receiving coupler 202, receiving circuit 203, four receiving circuits 204, gate drive circuit 205, and four motor drive circuits 206 shown in Figure 1 are omitted from this diagram.

[0023] For example, the transmitting antenna 101 detects at least one of the signals of the receiving antenna 201's position, movement speed, or acceleration, and moves to follow the receiving antenna 201. Alternatively, the transmitting antenna 101 moves based on the movement control data of the receiving antenna 201. By controlling the movement of the transmitting antenna 101 to follow the receiving antenna 201 in this way, the relative positional relationship between the transmitting antenna 101 and the receiving antenna 201 can always be kept approximately constant. According to the configuration of the present invention, it is not necessary to lengthen the long side of the transmitting antenna 101 as shown in Figure 2, and it can be miniaturized. Also, in Figure 2, the receiving antenna 201 needed to be large in order to increase the coupling coefficient, but in the configuration of Figure 3, the transmitting antenna 101 and the receiving antenna 201 are always facing each other, so they can be the same size, and it is possible to increase the coupling coefficient even if the receiving antenna 201 is small. By miniaturizing the transmitting antenna 101 and the receiving antenna 201, even when supplying power to multiple locations, it is possible to arrange them in multiple rows without taking up space, as shown in Figure 3. Furthermore, since no cables are connected to the coarse-movement stage 002, it is possible to improve the positioning accuracy of the stage. Also, a cable 005 is connected so that the power transmitting antenna 101 can move. Note that the cable 005 may be a conductor configured on a flexible substrate, for example, or it may be a coaxial cable. In other words, multiple power transmitting antennas and multiple power transmitting circuits are connected via the cable 005 to supply power to the power transmitting antennas. Note that the power transmitting antennas and power transmitting circuits may be formed as a single unit, and the cable 005 may be configured to connect the power transmitting circuit and the power supply 104.

[0024] The case 306 is mounted to cover the power transmission cable 005 and the power transmission antenna 101, and is positioned inside the case 306. The air pressure inside the case 306 is kept negative compared to the air pressure outside the case 306. The case 306 may be made of metal or a dielectric material such as acrylic resin.

[0025] Although dust may be generated each time cable 005 expands or contracts, the case 306 is designed to prevent the spread of dust.

[0026] Figure 3(b) shows a cross-sectional view of the four transmitting and receiving antennas in this embodiment. Magnetic bodies 107 and 207 are mounted so as to cover the transmitting antenna 101 and the receiving antenna 201. Because the relative positions of the transmitting antenna 101 and the receiving antenna 201 are always approximately constant due to movement control, a closed magnetic loop can be generated by the magnetic bodies 107 and 207, making it possible to suppress electromagnetic noise that could adversely affect adjacent antennas and surrounding electronic circuits. Note that by arranging the magnetic bodies 107 and 207 on at least one surface excluding the opposing surfaces of the transmitting antenna 101 and the receiving antenna 201, it is possible to generate a closed magnetic loop to a considerable extent. Note that although Figure 3 only shows the receiving antenna 201 and describes a movable configuration, the receiving circuit connected to the receiving antenna also moves in the same way, as does the motor drive circuit connected to the receiving circuit. Furthermore, the receiving coupler, receiving circuit, and gate drive circuit also move in the same way. Note that the receiving circuit and the motor drive circuit may be composed of a single circuit. Specifically, it consists of a synchronous rectification circuit using four bidirectional switches.

[0027] (Efficiency of power transmission systems) Before comparing the configurations in Figure 2 and Figure 3, the transmission efficiency of the wireless power transmission system will be explained using an equation. Figure 4 shows the equivalent circuit of the electromagnetic field coupling section of the transmitting and receiving antennas of the wireless power transmission system. The inductive component of the transmitting antenna 101 is L1, the resistive component is r1, and the transmitting resonant capacitor is C1. The inductive component of the receiving antenna 201 is L2, the resistive component is r2, the receiving resonant capacitor is C2, and the input impedance of the receiving section is R L The coupling coefficient is denoted as k. The Q value (quality factor) of each antenna can be expressed as shown in Equation 1.

[0028]

number

[0029] The Q value is determined by the shape of the antenna. In this invention, the power transmission efficiency considering only antenna loss is defined as antenna efficiency η. Assuming that C1 and L1, and C2 and L2 each satisfy the resonance conditions, the antenna efficiency η can be expressed by Equation 2.

[0030]

number

[0031] Furthermore, R is the point at which power transmission efficiency is maximized. L This can be expressed by equation 3.

[0032]

number

[0033] R L =R L_opt When this is the case, the maximum antenna efficiency η can be obtained from equations 1, 2, and 3. max This can be expressed by equation 4.

[0034]

number

[0035] From equation 4, k 2 The larger the Q1Q2, the greater the maximum antenna efficiency η. max It can be confirmed that this becomes larger. In other words, by increasing the coupling coefficient between the transmitting and receiving antennas, it is possible to increase the inductance component value of each antenna and decrease the resistance component value, thereby improving power transmission efficiency.

[0036] (Comparison results with conventional technology) Next, using Figures 5 and 6, we compare the simulation results for the configurations in Figure 2 and Figure 3, demonstrating the advantageous effects of the configuration in Figure 3.

[0037] Figure 5 shows a simulation model comparing the conventional wireless power transmission system with the present invention in a simulation. Figure 5(a) is a model assuming the conventional wireless power transmission system, and has a transmitting antenna 101, a magnetic body 107, a receiving antenna 201, and a magnetic body 207. The long side of the transmitting antenna 101 is set to 600 mm, taking into account the movable range of the receiving antenna 201. The long side of the receiving antenna 201 is set to 100 mm, taking into account the available mounting space. Figure 5(b) is a model assuming the wireless power transmission system of the present invention, and has a transmitting antenna 101, a magnetic body 107, a receiving antenna 201, and a magnetic body 207. The transmitting antenna 101 and the receiving antenna 207 are the same size, with a long side of 32 mm and a short side of 12 mm.

[0038] Figure 6 shows the simulation results for each model. Figure 6(a) shows the Q values ​​of each antenna. The horizontal axis is frequency, and the vertical axis is Q value. The solid gray line represents the transmitting antenna 101 with the configuration of Figure 5(a), and the dashed gray line represents the receiving antenna 201 with the configuration of Figure 5(a). The solid black lines represent the transmitting antenna 101 and receiving antenna 201 with the configuration of Figure 5(b). From Figure 6(a), it can be seen that the Q values ​​of the transmitting antenna 101 and receiving antenna 201 with the configuration of Figure 3 are higher than those of the transmitting antenna 101 and receiving antenna 201 with the configuration of Figure 2. Note that if there is only one solid black line, it is because the configuration of the transmitting antenna and the receiving antenna are the same, and therefore their characteristics are the same.

[0039] Figure 6(b) is a diagram comparing the coupling coefficient k. The horizontal axis represents frequency, and the vertical axis represents the coupling coefficient k. The solid black line represents the coupling coefficient k of this embodiment, and the solid gray line represents the coupling coefficient k of the conventional technology. In the conventional technology, because the size ratio of the transmitting antenna 101 to the receiving antenna 201 is large, a large amount of magnetic flux generated by the transmitting antenna 101 does not link with the receiving antenna 201, resulting in a decrease in the coupling coefficient k. In the present invention, since the transmitting antenna 101 and the receiving antenna 201 are the same size, the magnetic flux generated by the transmitting antenna 100 is more likely to link with the receiving antenna 201, and the coupling coefficient k is higher than in the conventional technology.

[0040] Fig. 6(c) shows the maximum antenna efficiency η max It is a figure which shows. The horizontal axis is the frequency, and the vertical axis is the maximum antenna efficiency η max [%]. The solid black line is the graph of this embodiment, and the solid gray line is the graph of the prior art. From Fig. 6(c), it can be confirmed that the antenna according to this embodiment can improve the maximum efficiency η max compared with the antenna according to the prior art. As can be seen from Equation 4, this is because the Q value and the coupling coefficient k have been improved respectively. Therefore, by applying the present invention, it is possible to improve the power transmission efficiency.

[0041] (Second Embodiment) In the first embodiment, a configuration in which the plurality of power transmission antennas 101 and the plurality of power reception antennas 201 move in parallel in accordance with the operation of the coarse movement stage while maintaining the facing positional relationship has been shown. In the second embodiment, the configuration of the power transmission unit in which the cable 005 in Fig. 3 is eliminated will be described.

[0042] An example of the configuration diagram of the power transmission unit in this embodiment is shown in Fig. 7.

[0043] The power transmission unit includes a power transmission antenna 101, a power transmission circuit 106, a case 500, a power supply rail 501, a GND rail 502, a power supply contact 503, and a GND contact 504.

[0044] With this configuration, it is possible to realize a cableless power transmission system. The power supply rails 501 corresponding to each power transmission antenna 101 are arranged in parallel, and each is connected by a power supply contact 503. Each power transmission antenna 101 is connected to the same GND rail 502 by a GND contact 504 respectively. <00002​​​​The power supply contact 503 and the GND contact 504 are spring contacts. The power transmission unit is located inside the case 500, and the air pressure inside the case 500 is maintained at a negative pressure compared to the outside of the case 500.

[0047] The transmitting antenna 101, the transmitting circuit 106, the power contact 503, and the GND contact 504 slide along the power rail 501 and the GND rail 502. The method for controlling the movement of the transmitting antenna 101 is the same as in Embodiment 1, and in this embodiment as well, the relative positions of the transmitting antenna 101 and the receiving antenna 201 can be kept substantially constant. Therefore, by arranging the magnetic bodies 107 and 207 as shown in Figure 3(a), a closed magnetic loop can be realized, enabling highly efficient power transmission. Furthermore, by eliminating the cable 005, the risk of cable breakage can be eliminated, improving the product lifespan. In addition, maintenance such as cable replacement can be reduced.

[0048] Furthermore, the embodiments of this disclosure described above are merely examples of concrete implementations of this disclosure, and the technical scope of this disclosure should not be interpreted as being limited by them. In other words, this disclosure can be implemented in various ways without departing from its technical concept or its main features.

[0049] This embodiment includes the following configuration.

[0050] (Item 1) A wireless power transmission system, Multiple receiving antennas that move in a predetermined direction, A power receiving unit having multiple power receiving circuits connected to each of the aforementioned power receiving antennas, Multiple transmitting antennas facing each of the aforementioned multiple receiving antennas and electromagnetically coupled, A power transmission unit having multiple power transmission circuits connected to each of the multiple power transmission antennas, It has, A wireless power transmission system characterized in that the plurality of transmitting antennas move such that their relative positions to the plurality of receiving antennas remain substantially constant.

[0051] (Item 2) The wireless power transmission system according to item 1, characterized in that the power transmission unit further has a cable connecting the plurality of power transmission antennas and the plurality of power transmission circuits, and the cable is arranged inside the case.

[0052] (Item 3) The wireless power transmission system according to item 1 or item 2, characterized in that at least one surface of the plurality of receiving antennas and the plurality of transmitting antennas, excluding opposing surfaces, is covered with a magnetic material.

[0053] (Item 4) The wireless power transmission system according to any one of items 1 to 3, characterized in that the plurality of transmitting antennas detect signals of at least one of the position, movement speed, or acceleration of the plurality of receiving antennas and move in parallel.

[0054] (Item 5) The wireless power transmission system according to any one of items 1 to 4, characterized in that the plurality of transmitting antennas move in parallel based on the movement control data of the plurality of receiving antennas.

[0055] (Item 6) The power transmission unit further has multiple contacts and multiple power supply rails, A wireless power transmission system according to any one of items 1 to 5, characterized in that the plurality of power transmission circuits and the plurality of power rails are connected via the plurality of contacts.

[0056] (Item 7) The aforementioned power transmission unit further has a rail for GND. The wireless power transmission system according to any one of items 1 to 6, characterized in that the plurality of power transmission circuits and the GND rail are connected via a plurality of contacts.

[0057] (Item 8) The wireless power transmission system according to item 2, characterized in that the cable is configured on a flexible substrate.

[0058] (Item 9) The wireless power transmission system according to item 7, characterized in that the plurality of power rails and the GND rail are configured to extend parallel to the direction of movement of the plurality of power receiving antennas.

[0059] (Item 10) A wireless power transmission system according to any one of items 1 to 9, characterized by supplying power to the motor of the coarse stage of a semiconductor exposure apparatus.

[0060] (Item 11) Multiple receiving antennas that move in a predetermined direction, A power receiving unit having multiple power receiving circuits connected to each of the aforementioned power receiving antennas, Multiple transmitting antennas facing each of the aforementioned multiple receiving antennas and electromagnetically coupled, A power transmission unit having multiple power transmission circuits connected to each of the multiple power transmission antennas, A control method for a wireless power transmission system having, The plurality of power transmission circuits each supply power to the plurality of power transmission antennas to which they are connected, A control method characterized by having a movement step in which the plurality of transmitting antennas move so that their relative positions with respect to the plurality of receiving antennas remain substantially constant. [Explanation of symbols]

[0061] 100 Power transmission section 101 Power transmission antenna 102 Transmitter coupler 103 Controller 104 Power supply 105 Transmitter Circuit 106 Power transmission circuit 201 Receiving Antenna 202 Receiving coupler 203 Receiving Circuit 204 Power Receiving Circuit 205 Gate drive circuit 206 Motor drive circuit 300 Wireless Power Transmission Systems 400 motor

Claims

1. A wireless power transmission system, Multiple receiving antennas that move in a predetermined direction, A power receiving unit having multiple power receiving circuits connected to each of the aforementioned power receiving antennas, Multiple transmitting antennas facing each of the aforementioned multiple receiving antennas and electromagnetically coupled, A power transmission unit having multiple power transmission circuits connected to each of the multiple power transmission antennas, It has, A wireless power transmission system characterized in that the plurality of transmitting antennas move such that their relative positions to the plurality of receiving antennas remain substantially constant.

2. The wireless power transmission system according to claim 1, wherein the power transmission unit further has a cable connecting the plurality of power transmission antennas and the plurality of power transmission circuits, and the cable is arranged inside the case.

3. The wireless power transmission system according to claim 1, characterized in that at least one surface of the plurality of receiving antennas and the plurality of transmitting antennas, excluding the opposing surfaces, is covered with a magnetic material.

4. The wireless power transmission system according to claim 1, characterized in that the plurality of transmitting antennas detect signals of at least one of the position, movement speed, or acceleration of the plurality of receiving antennas and move in parallel.

5. The wireless power transmission system according to claim 1, characterized in that the plurality of power transmitting antennas move in parallel based on the movement control data of the plurality of power receiving antennas.

6. The power transmission unit further has multiple contacts and multiple power supply rails, The wireless power transmission system according to claim 1, characterized in that the plurality of power transmission circuits and the plurality of power rails are connected via the plurality of contacts.

7. The aforementioned power transmission unit further has a rail for GND, The wireless power transmission system according to claim 6, characterized in that the plurality of power transmission circuits and the GND rail are connected via a plurality of contacts.

8. The wireless power transmission system according to claim 2, characterized in that the cable is configured on a flexible substrate.

9. The wireless power transmission system according to claim 7, characterized in that the plurality of power rails and the GND rail are configured to extend parallel to the direction of movement of the plurality of power receiving antennas.

10. A wireless power transmission system according to any one of claims 1 to 9, characterized by supplying power to the motor of the coarse stage of a semiconductor exposure apparatus.

11. Multiple receiving antennas that move in a predetermined direction, A power receiving unit having multiple power receiving circuits connected to each of the aforementioned power receiving antennas, Multiple transmitting antennas facing each of the aforementioned multiple receiving antennas and electromagnetically coupled, A power transmission unit having multiple power transmission circuits connected to each of the multiple power transmission antennas, A control method for a wireless power transmission system having, The plurality of power transmission circuits each supply power to the plurality of power transmission antennas to which they are connected, A control method characterized by having a movement step in which the plurality of transmitting antennas move so that their relative positions with respect to the plurality of receiving antennas remain substantially constant.

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