JPWO2012132143A1 - Charging stand - Google Patents

Abstract

The position of a power receiving coil is accurately detected even if the level of an echo signal induced in the position detecting coil varies.
A charging stand detects a position of a power receiving coil 51 of a battery built-in device 50 placed on an upper plate 21 by a position detection controller 14 and controls a moving mechanism 13 to bring the power transmitting coil 11 closer to the power receiving coil 51. To carry power. The position detection controller 14 supplies a pulse signal from the detection pulse generation circuit 31 to the plurality of position detection coils 30 arranged on the upper surface plate 21, and echoes an echo signal induced from the power reception coil 51 to the position detection coil 30. The signal is received by the amplifier circuit 32 and the position of the power receiving coil 51 is determined by the identification circuit 33. The echo amplification circuit 32 includes a gain adjustment circuit 37 that adjusts the amplification factor so as to linearly amplify the input echo signal without being saturated, and the echo amplification circuit 32 with the specified amplification factor is connected to the position detection coil 30. The input echo signal is amplified and input to the identification circuit 33.
[Selection] Figure 9

Description

  The present invention relates to a charging base on which a battery built-in device such as a battery pack or a mobile phone is placed on top, and power is transferred by electromagnetic induction to charge the built-in battery.

  A charging stand has been developed that carries power from the power transmission coil to the power receiving coil by the action of electromagnetic induction and charges the built-in battery. This charging stand incorporates a power transmission coil that is excited by an AC power source. A battery built-in device such as a battery pack or a portable device set on a charging base has a power receiving coil that is electromagnetically coupled to a power transmission coil of the charging base. The battery built-in device also has a built-in circuit for rectifying the alternating current induced in the power receiving coil and supplying the battery to the battery for charging. According to this structure, the battery pack can be charged in a non-contact state by placing the battery pack on the charging stand.

  The above charging stand can be conveniently used by moving the power transmission coil to the position of the power receiving coil. This is because the user can set the battery built-in device at a free position on the charging stand and charge the power receiving coil of the battery built-in device close to the power receiving coil. A charging stand has been developed to achieve this. (See Patent Document 1)

JP 2009-247194 A

  The above charging stand includes a moving mechanism that moves the power transmission coil so as to approach the power receiving coil. In order to control the moving mechanism, a position detection controller for detecting the position of the power receiving coil and controlling the transfer mechanism is provided. In order to detect the position of the power receiving coil, the position detection controller fixes a plurality of position detection coils to the upper surface plate of the case on which the battery built-in device is placed. The position detection coils are fixed at regular intervals. A detection pulse generating circuit for supplying a pulse signal is connected to each position detection coil. When a pulse signal is supplied from the detection pulse generating circuit to the position detection coil, the pulse signal is excited to output an echo signal from the power receiving coil to the position detection coil. Since the echo signal is output from the power receiving coil excited by the pulse signal, the echo signal is guided to the position detection coil with a certain time delay from the pulse signal. In order to receive this echo signal, an echo amplification circuit is connected to the position detection coil. The echo signal received by the echo amplifier circuit is input to an identification circuit that detects the position of the power receiving coil. The identification circuit determines the position of the power receiving coil from the level of the input echo signal.

  The above position detection controller outputs a pulse signal in order to each position detection coil by a detection pulse generation circuit. The identification circuit can detect the position of the power receiving coil from the level of the echo signal induced in each position detection coil. When the echo signal induced in the position detection coil closest to the power receiving coil becomes the largest and the power receiving coil 151 is in the middle of the two position detecting coils 130, as shown by the point B in FIG. The levels of echo signals induced in the X-axis position detection coil 130A and the second X-axis position detection coil 130A are the same. That is, in each X-axis position detection coil 130A, the level of the echo signal that is induced when the power receiving coil 151 is closest is the strongest, and the level of the echo signal decreases as the power receiving coil 151 moves away. Therefore, it can be determined which X-axis position detection coil the power receiving coil is closest to which X-axis position detection coil has the strongest echo signal level. Further, when an echo signal is induced in two adjacent X-axis position detection coils, it can be determined which of the level ratios of the echo signals is closer to the position detection coil.

  The above position detection controller outputs a pulse signal from the position detection coil to the power receiving coil, detects the level of the echo signal output from the power receiving coil excited by the pulse signal to the position detection coil, and detects the position of the power receiving coil. Is detected. Since the level of the echo signal induced in the position detection coil is extremely small, it is amplified by the echo amplification circuit and input to the identification circuit. The echo amplification circuit amplifies the echo signal with a constant amplification factor. This position detection controller has a drawback that the position of the power receiving coil cannot be accurately detected depending on the model of the battery built-in device set on the charging stand. This is because the level of the echo signal induced from the power receiving coil to the position detecting coil varies due to changes in the size of the power receiving coil of the battery built-in device, the Q of the resonance circuit, and the interval between the position detecting coil and the power receiving coil. It is.

  If the amplification factor of the echo amplifier circuit is set to be small so as to be optimal for a battery built-in device having a large echo signal level, the position of the power receiving coil of the battery built-in device having a small echo signal level cannot be detected accurately. This is because if the level of the echo signal is small, the level of the echo signal cannot be accurately detected due to quantization noise or external noise. On the other hand, even if the amplification factor of the echo amplifier circuit is adjusted to a large value so that it is optimal for devices with a low echo signal level, it is possible to accurately detect the position of the power receiving coil of the device with a high echo signal level. Disappear. This is because the echo signal of a large level input to the echo amplifier circuit is saturated, and the echo signal is outside the region where it can be linearly amplified. That is, it becomes impossible to accurately detect the positions of the power receiving coils of all the battery built-in devices by setting various types of battery built-in devices.

  In order for the discriminating circuit to accurately detect the position of the receiving coil from the level of the echo signal, the echo amplifying circuit is amplified linearly, that is, with a certain gain so as to be directly proportional to the level of the input echo signal, and discriminating. Must be input to the circuit. The echo amplification circuit has a maximum output level limited by the power supply voltage, and generally can output a signal level of 70% to 80% of the power supply voltage linearly. Further, if the level of the echo signal input to the identification circuit is small, the echo signal amplified to a predetermined level cannot be input to the identification circuit, and the identification circuit cannot accurately detect the position of the power receiving coil. The identification circuit converts the level of the echo signal that is amplified and input into a digital signal and calculates the position of the power receiving coil. However, if the signal level is low, an error due to quantization noise increases. For example, an identification circuit that converts an echo signal input from an echo amplifier circuit into an 8-bit digital signal and detects the position of the receiving coil decomposes the input echo signal into 256 gradations, The position can be detected accurately. However, when the level of the echo signal is halved, the position of the receiving coil is detected from the echo signal level because the position of the receiving coil is detected by decomposing the echo signal into 128 gradations.

  In order to accurately detect the position of the power receiving coil from the echo signal, even if the level of the echo signal input from the position detection coil is small, it is amplified to an optimum level for discrimination of the discrimination circuit, and a large level echo signal is It is necessary to input to the identification circuit without saturation. However, amplifying a small level echo signal to an optimum level for detecting the position of the receiving coil and inputting it to the identification circuit without saturating the large level echo signal are mutually contradictory characteristics. Can not be satisfied. For this reason, it is difficult for the conventional position detection controller to always accurately detect the position of the power receiving coil, and there is a problem that the position of the power receiving coil cannot be accurately detected depending on the battery built-in device.

  In order to eliminate the above drawbacks, the charging stand of Patent Document 1 is provided with a corrected position detection controller that more accurately detects the position of the power receiving coil. This charging stand roughly detects the position of the power receiving coil with the position detection controller, and after making the power transmission coil approach the power receiving coil, further detects the position of the power receiving coil with the corrected position detection controller, The power transmission coil is moved closer to the power reception coil.

  The correction position detection controller controls the moving mechanism by accurately detecting the position of the power receiving coil from the oscillation frequency of the oscillation circuit using an AC power source that outputs an AC signal to the power transmission coil as a self-excited oscillation circuit. The correction position detection controller detects the oscillation frequency of the AC power supply by moving the power transmission coil. FIG. 14 shows the characteristic that the oscillation frequency of the self-excited oscillation circuit changes. This figure shows the change in the oscillation frequency with respect to the relative displacement between the power transmission coil and the power reception coil. As shown in this figure, the oscillation frequency of the self-excited oscillation circuit is highest at the position where the power transmission coil is closest to the power reception coil, and the oscillation frequency is lowered as the relative position is shifted. Therefore, the corrected position detection controller can move the power transmission coil, stop at the position where the oscillation frequency is highest, and approach the power transmission coil to the power reception coil. This charging stand requires a dedicated circuit configuration to detect the position of the power transmission coil more accurately in order to bring the power transmission coil closer to the power reception coil. For this reason, there exists a fault which a position detection controller becomes complicated and a manufacturing cost becomes high.

  The present invention has been developed for the purpose of solving the above-mentioned drawbacks. An important object of the present invention is to accurately detect the position of the power receiving coil even when the level of the echo signal induced in the position detecting coil fluctuates, and to efficiently carry power by bringing the power transmitting coil closer to the power receiving coil. To provide a charging stand.

Means for Solving the Problems and Effects of the Invention

  The charging stand according to the present invention is a charging stand for the battery built-in device 50 including the battery 52 that is charged by the power conveyed to the power receiving coil 51. The charging stand is connected to the AC power source 12 and includes a power transmission coil 11 that carries electromotive force to the power receiving coil 51, and a case having the power transmission coil 11 and an upper surface plate 21 on which the battery built-in device 50 is placed on the upper surface. 20, detecting the position of the moving mechanism 13 built in the case 20 and moving the power transmission coil 11 along the inner surface of the upper surface plate 21, and the position of the power receiving coil 51 of the battery built-in device 50 mounted on the upper surface plate 21. Position detection controllers 14 and 64 that control the moving mechanism 13 to cause the power transmission coil 11 to approach the power reception coil 51 are provided. The position detection controllers 14 and 64 include a plurality of position detection coils 30 arranged at predetermined intervals on the back side of the top plate 21, and a detection pulse generation circuit 31 that supplies a pulse signal as a position detection signal to the position detection coil 30. An echo amplification circuit 32 that receives an echo signal that is excited by a pulse signal supplied from the detection pulse generation circuit 31 to the position detection coil 30 and is induced from the power reception coil 51 to the position detection coil 30; And an identification circuit 33 for discriminating the position of the power receiving coil 51 from the echo signal output from the input signal 32. The echo amplification circuit 32 includes a gain adjustment circuit 37 that adjusts the amplification factor so that the echo signal input from the position detection coil 30 is linearly amplified without being saturated, and the gain adjustment circuit 37 specifies the amplification factor. The echo amplifying circuit 32 amplifies the echo signal input from the position detection coil 30 and inputs it to the identification circuit 33.

  The above charging stand detects the position of the receiving coil accurately even if the level of the echo signal induced in the position detecting coil varies depending on the model of the battery built-in device to be set, and the transmitting coil becomes the receiving coil. It has the feature that it can approach and efficiently carry power. This is because the charging base described above sets the amplification factor of the echo amplification circuit to an optimum value by the gain adjustment circuit, amplifies the echo signal induced in the position detection coil, and inputs it to the identification circuit. The echo amplification circuit whose gain is set to the optimum value by the gain adjustment circuit does not saturate the echo signal even if the echo signal changes from a large level to a small level, and linearly amplifies it at a constant gain. It can be input at the optimum level for the identification circuit.

In the charging stand of the present invention, the echo amplifier circuit 32 includes a differential amplifier 38, the gain adjustment circuit 37 inputs an amplification factor adjustment voltage to one input terminal of the differential amplifier 38, and the amplification factor of the differential amplifier 38. Can be adjusted.
The above charging stand can set the amplification factor of the echo amplifier circuit to an optimum value with a simple circuit configuration.

In the charging stand according to the present invention, the gain adjustment circuit 37 includes a voltage adjustment circuit 39 that outputs a gain adjustment voltage by smoothing a signal output by PWM modulation, and the gain adjustment voltage output from the voltage adjustment circuit 39. Can be input to one input terminal of the differential amplifier 38 to adjust the amplification factor of the differential amplifier 38.
The above charging stand can set the amplification factor of the differential amplifier with a voltage adjustment circuit having a simple circuit configuration.

The charging stand of the present invention includes a multiplexer 34 that sequentially connects each position detection coil 30 to a detection pulse generation circuit 31 and an echo amplification circuit 32, and balance adjustment that eliminates an imbalance in the internal resistance of the multiplexer 34. A portion 44 can be provided.
The above charging stand can eliminate the imbalance due to the internal resistance of the multiplexer, and more accurately determine the position of the power receiving coil from the level of the echo signal.

In the charging stand of the present invention, the balance adjustment unit 44 has a drive mechanism 47 that moves the power transmission coil 11 in the arrangement direction of the position detection coils 30, and a pulse signal output from the position detection coil 30 to the power transmission coil 11. By detecting the level of the echo signal output from the power transmission coil 11 to the position detection coil 30, the imbalance due to the internal resistance of the multiplexer 34 can be eliminated.
Since the charging stand described above uses the power transmission coil in combination with the detection of the imbalance of the internal resistance of the multiplexer, the imbalance of the internal resistance of the multiplexer can be detected with a simple circuit configuration.

In the charging stand of the present invention, the drive mechanism 47 moves the power transmission coil 11 to the center of each position detection coil 30, and the balance adjustment unit 44 uses the echo signal from the power transmission coil 11 to change the internal resistance of the multiplexer 34. Can be eliminated.
The above charging stand uses the power transmission coil to detect the unbalance of the internal resistance of the multiplexer, and also uses the moving structure to approach the power receiving coil to detect the unbalance of the internal resistance of each channel of the multiplexer. There are features that can be done. Therefore, there is a feature that the internal resistance of each channel of the multiplexer can be detected without adding a dedicated circuit or structure.

  In the charging stand according to the present invention, the position detection coil 30 is arranged adjacent to the position detection coil 30 with a part of the position detection coil 30 arranged adjacently, and the identification circuit 33 has the maximum level. The position of the power receiving coil 51 can be determined from the position detection coil 30 from which the echo signal is induced and the levels of the echo signals of the position detection coils 30 disposed on both sides thereof.

  The above charging stand is characterized in that it can accurately detect the position of the power receiving coil with an echo signal induced in the position detecting coil, and efficiently convey power by bringing the power transmitting coil close to the power receiving coil. This is because the charging base described above is disposed by overlapping a part of the position detection coil adjacent to the adjacent position detection coil, and the identification circuit is a position where the maximum level echo signal is induced. This is because the position of the power reception coil is determined from the detection coil and the level of the echo signal of the position detection coil disposed on both sides of the detection coil. By arranging a part of the position detection coils arranged adjacent to each other so as to overlap each other, as shown in FIG. 12, the area where the level of the echo signal induced in one position detection coil becomes the maximum level, that is, In the peak vicinity region, the level of the echo signal induced in the position detection coils arranged on both sides of the peak detection region can be increased, and the width of the zero level region of the echo signal of the position detection coil on both sides in the peak vicinity region can be reduced. Further, in the vicinity of the peak, the identification circuit determines the position of the receiving coil not only from the echo signal of the maximum level but also from the level of the echo signal induced in the position detection coils on both sides. The position of the power receiving coil can be determined more accurately.

In the charging stand according to the present invention, the position detection coil 30 is an elongated coil having a straight portion, and the adjacent position detection coils 30 are arranged so as to be displaced in a direction perpendicular to the longitudinal direction of the coils and adjacent to each other so as to overlap each other. Thus, the overlapping amount (d) of the position detection coils 30 can be set to 1/2 to 9/10 of the lateral width (W) of the elongated coil.
The above charging stand can accurately detect the position of the power receiving coil in the direction in which the elongated position detecting coils are arranged. In particular, it is possible to accurately detect the position of the power receiving coil by arranging the linear portions constituting the position detecting coil at equal intervals. Further, by reducing the overlapping amount (d) between the position detection coils adjacent to each other to be smaller than the lateral width (W) of the position detection coil, the level of the echo signals of the position detection coils on both sides in the peak vicinity region is increased. The position of the coil can be accurately detected.

It is a schematic perspective view of the charging stand concerning one Example of this invention. It is a schematic block diagram of the charging stand concerning one Example of this invention. It is a vertical longitudinal cross-sectional view of the charging stand shown in FIG. It is a vertical cross-sectional view of the charging stand shown in FIG. It is a circuit diagram which shows the position detection controller of the charging stand concerning one Example of this invention. It is a block diagram of the charging stand and battery built-in apparatus concerning one Example of this invention. It is the schematic which shows the state which the position detection coil shown in FIG. 5 overlaps. It is a figure which shows an example of the echo signal output from the receiving coil excited with the pulse signal. It is a circuit diagram which shows an example of an echo amplifier circuit. It is a block diagram which shows an example of a balance adjustment part. It is a circuit diagram which shows the position detection controller of the charging stand concerning the other Example of this invention. It is a figure which shows the level of the echo signal induced | guided | derived to the position detection coil of the position detection controller shown in FIG. It is a figure which shows the level of the echo signal induced | guided | derived to the position detection coil of the conventional charging stand. It is a figure which shows the level of the echo signal with respect to the relative position shift of a power transmission coil and a receiving coil.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a charging stand for embodying the technical idea of the present invention, and the present invention does not specify the charging stand as follows. In addition, the member shown by the claim is not what specifies the member of embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

  1 to 6 show a schematic configuration diagram and a principle diagram of a charging stand. As shown in FIGS. 1 and 6, the charging stand 10 places the battery built-in device 50 on the charging stand 10 and charges the built-in battery 52 of the battery built-in device 50 by magnetic induction. The battery built-in device 50 includes a power receiving coil 51 that is electromagnetically coupled to the power transmitting coil 11. A battery 52 that is charged with electric power induced in the power receiving coil 51 is incorporated. Here, the battery built-in device 50 may be a battery pack.

  FIG. 6 is a circuit diagram of the battery built-in device 50. The battery built-in device 50 has a capacitor 53 connected in parallel with the power receiving coil 51. The capacitor 53 and the power receiving coil 51 constitute a parallel resonance circuit 54. The battery built-in device 50 of FIG. 6 includes a rectifier circuit 57 including a diode 55 that rectifies an alternating current output from the power receiving coil 51, a smoothing capacitor 56 that smoothes the rectified pulsating current, and an output from the rectifier circuit 57. And a charge control circuit 58 for charging the battery 52 with a direct current. The charge control circuit 58 detects the full charge of the battery 52 and transmits a full charge signal indicating that the battery 52 is fully charged to the charging stand 10. The charging stand 10 detects a full charge signal and stops charging.

  As shown in FIGS. 1 to 6, the charging stand 10 includes a power transmission coil 11 that is connected to an AC power source 12 and conveys power to the power receiving coil 51, and the power transmission coil 11. A case 20 having an upper surface plate 21 on which the power receiving coil 51 is mounted, a moving mechanism 13 that is built in the case 20 and moves the power transmission coil 11 along the inner surface of the upper surface plate 21 to approach the power receiving coil 51, and the upper surface plate 21. And a position detection controller 14 that detects the position of the battery built-in device 50 to be mounted and controls the moving mechanism 13 to bring the power transmission coil 11 closer to the power receiving coil 51 of the battery built-in device 50. The charging stand 10 includes a power transmission coil 11, an AC power source 12, a moving mechanism 13, and a position detection controller 14 in a case 20.

The charging stand 10 charges the built-in battery 52 of the battery built-in device 50 by the following operation.
(1) When the battery built-in device 50 is placed on the upper surface plate 21 of the case 20, the position detection controller 14 detects the position of the battery built-in device 50.
(2) The position detection controller 14 that has detected the position of the battery built-in device 50 controls the moving mechanism 13 to move the power transmission coil 11 along the upper surface plate 21 with the moving mechanism 13, thereby Approach the power receiving coil 51.
(3) The power transmission coil 11 approaching the power reception coil 51 is electromagnetically coupled to the power reception coil 51 and carries AC power to the power reception coil 51.
(4) The battery built-in device 50 rectifies the AC power of the power receiving coil 51 and converts it into direct current, and charges the built-in battery 52 with this direct current.

  The charging stand 10 that charges the battery 52 of the battery built-in device 50 by the above operation has the power transmission coil 11 connected to the AC power supply 12 built in the case 20. The power transmission coil 11 is disposed below the upper surface plate 21 of the case 20 and is disposed so as to move along the upper surface plate 21. The efficiency of power transfer from the power transmission coil 11 to the power reception coil 51 can be improved by bringing the power transmission coil 11 closer to the power reception coil 51. Therefore, the power transmission coil 11 is disposed below the top plate 21 and as close to the top plate 21 as possible. Since the power transmission coil 11 moves so as to approach the power reception coil 51 of the battery built-in device 50 placed on the upper surface plate 21, the power transmission coil 11 is disposed so as to be movable along the lower surface of the upper surface plate 21.

  The case 20 containing the power transmission coil 11 is provided with a flat upper surface plate 21 on which the battery built-in device 50 is placed on the upper surface. The charging stand 10 shown in the figure is disposed horizontally with the entire top plate 21 as a flat surface. The upper surface plate 21 has such a size that various battery built-in devices 50 having different sizes and outer shapes can be placed thereon, for example, a quadrangle having a side of 5 cm to 30 cm, or a circle having a diameter of 5 cm to 30 cm. The charging stand according to the present invention can also charge a built-in battery in order by mounting a plurality of battery-equipped devices together so that the top plate is enlarged, that is, a size capable of simultaneously loading a plurality of battery-equipped devices. . The top plate can also be provided with a peripheral wall around it, and a battery built-in device can be set inside the peripheral wall to charge the built-in battery.

  The power transmission coil 11 is wound in a spiral shape on a surface parallel to the upper surface plate 21 and radiates an alternating magnetic flux above the upper surface plate 21. The power transmission coil 11 radiates an alternating magnetic flux orthogonal to the upper surface plate 21 above the upper surface plate 21. The power transmission coil 11 is supplied with AC power from the AC power source 12 and radiates AC magnetic flux above the upper surface plate 21. The power transmission coil 11 can increase the inductance by winding a wire around a core 15 made of a magnetic material. The core 15 is made of a magnetic material such as ferrite having a high magnetic permeability, and has a bowl shape that opens upward. The bowl-shaped core 15 has a shape in which a columnar portion 15A disposed at the center of a power transmission coil 11 wound in a spiral shape and a cylindrical portion 15B disposed on the outside are connected at the bottom. The power transmission coil 11 having the core 15 can concentrate the magnetic flux to a specific portion and efficiently transmit power to the power reception coil 51. However, the power transmission coil does not necessarily need to be provided with a core, and may be an air-core coil. Since the air-core coil is light, a moving mechanism for moving it on the inner surface of the upper plate can be simplified. The power transmission coil 11 is substantially equal to the outer diameter of the power reception coil 51 and efficiently conveys power to the power reception coil 51.

  For example, the AC power supply 12 supplies high-frequency power of 20 kHz to 1 MHz to the power transmission coil 11. The AC power supply 12 is connected to the power transmission coil 11 via a flexible lead wire 16. This is because the power transmission coil 11 is moved so as to approach the power reception coil 51 of the battery built-in device 50 placed on the upper surface plate 21. Although not shown, the AC power supply 12 includes an oscillation circuit and a power amplifier that amplifies the AC output from the oscillation circuit.

  The power transmission coil 11 is moved by the moving mechanism 13 so as to approach the power reception coil 51. The moving mechanism 13 in FIGS. 1 to 4 moves the power transmission coil 11 along the upper surface plate 21 in the X-axis direction and the Y-axis direction to approach the power receiving coil 51. The moving mechanism 13 shown in the figure rotates the screw rod 23 by the servo motor 22 controlled by the position detection controller 14 to move the nut member 24 screwed into the screw rod 23, and the power transmission coil 11 is moved to the power receiving coil 51. To approach. The servo motor 22 includes an X-axis servo motor 22A that moves the power transmission coil 11 in the X-axis direction, and a Y-axis servo motor 22B that moves the Y-axis direction. The screw rod 23 includes a pair of X-axis screw rods 23A that move the power transmission coil 11 in the X-axis direction, and a Y-axis screw rod 23B that moves the power transmission coil 11 in the Y-axis direction. The pair of X-axis screw rods 23A are arranged in parallel to each other, driven by the belt 25, and rotated together by the X-axis servomotor 22A. The nut member 24 includes a pair of X-axis nut members 24A screwed into the respective X-axis screw rods 23A, and a Y-axis nut member 24B screwed into the Y-axis screw rods 23B. The Y-axis screw rod 23B is coupled so that both ends thereof can be rotated to a pair of X-axis nut members 24A. The power transmission coil 11 is connected to the Y-axis nut member 24B.

  Further, the moving mechanism 13 shown in the figure has a guide rod 26 disposed in parallel with the Y-axis screw rod 23B in order to move the power transmission coil 11 in the Y-axis direction in a horizontal posture. Both ends of the guide rod 26 are connected to the pair of X-axis nut members 24A and move together with the pair of X-axis nut members 24A. The guide rod 26 penetrates the guide portion 27 coupled to the power transmission coil 11 so that the power transmission coil 11 can be moved along the guide rod 26 in the Y-axis direction. That is, the power transmission coil 11 moves in the Y-axis direction in a horizontal posture via the Y-axis nut member 24 </ b> B and the guide portion 27 that move along the Y-axis screw rod 23 </ b> B and the guide rod 26 arranged in parallel to each other. To do.

  In the moving mechanism 13, when the X-axis servo motor 22A rotates the X-axis screw rod 23A, the pair of X-axis nut members 24A move along the X-axis screw rod 23A, and the Y-axis screw rod 23B and the guide rod 26 is moved in the X-axis direction. When the Y-axis servo motor 22B rotates the Y-axis screw rod 23B, the Y-axis nut member 24B moves along the Y-axis screw rod 23B, and moves the power transmission coil 11 in the Y-axis direction. At this time, the guide part 27 connected to the power transmission coil 11 moves along the guide rod 26 to move the power transmission coil 11 in the Y-axis direction in a horizontal posture. Therefore, the rotation of the X-axis servomotor 22A and the Y-axis servomotor 22B can be controlled by the position detection controller 14, and the power transmission coil 11 can be moved in the X-axis direction and the Y-axis direction. However, the charging stand of the present invention does not specify the moving mechanism as the above mechanism. This is because any mechanism that can move the power transmission coil in the X-axis direction and the Y-axis direction can be used as the moving mechanism.

  Furthermore, the charging stand of the present invention does not specify the moving mechanism as a mechanism that moves the power transmission coil in the X-axis direction and the Y-axis direction. That is, the charging stand of the present invention has a structure in which a linear guide wall is provided on the upper plate, and a battery built-in device is placed along the guide wall, and the power transmission coil can be moved linearly along the guide wall. Because it can be done. Although this charging stand is not shown, the power transmission coil can be moved linearly along the guide wall as a moving mechanism that can move the power transmission coil only in one direction, for example, the X-axis direction.

  The position detection controller 14 detects the position of the battery built-in device 50 placed on the top plate 21. The position detection controller 14 in FIGS. 1 to 4 detects the position of the power receiving coil 51 built in the battery built-in device 50, and causes the power transmitting coil 11 to approach the power receiving coil 51.

  As shown in FIG. 5, the position detection controller 14 generates a plurality of position detection coils 30 fixed to the inner surface of the upper surface plate 21, and generates a detection pulse for supplying a pulse signal as a position detection signal to the position detection coil 30. A circuit 31, and an echo amplification circuit 32 that receives an echo signal that is excited by a pulse of a position detection signal supplied from the detection pulse generation circuit 31 to the position detection coil 30 and output from the power reception coil 51 to the position detection coil 30. And an identification circuit 33 for determining the position of the power receiving coil 51 from the echo signal received by the echo amplifier circuit 32.

  The position detection coil 30 includes a plurality of rows of coils, and the plurality of position detection coils 30 are arranged on the back side of the top plate 21. The position detection coil 30 is fixed to the inner surface of the upper surface plate 21 and can be disposed on the back side of the upper surface plate 21. The position detection coil 30 includes a plurality of X-axis position detection coils 30A that detect the position of the power receiving coil 51 in the X-axis direction, and a plurality of Y-axis position detection coils 30B that detect a position in the Y-axis direction. The X-axis position detection coil 30A has a loop shape elongated in the Y-axis direction, and the plurality of X-axis position detection coils 30A are fixed to the inner surface of the upper surface plate 21 at a predetermined interval. The Y-axis position detection coil 30B has a loop shape elongated in the X-axis direction, and the plurality of Y-axis position detection coils 30B are fixed to the inner surface of the upper surface plate 21 at a predetermined interval.

  The position detection coil 30 is arranged such that a part of the position detection coil 30 disposed adjacent to the position detection coil 30 is overlapped with the adjacent position detection coil 30. The position detection coil 30 of the elongated coil is displaced in a direction orthogonal to the longitudinal direction of the coil, and the adjacent position detection coils 30 are arranged so as to overlap each other. The X-axis position detection coil 30A has an elongated loop shape having a linear portion extending in the Y-axis direction, and the plurality of X-axis position detection coils 30A are displaced in the X-axis direction by a predetermined amount of overlap. It arrange | positions on the back side of the upper surface plate 21 so that it may become (d). The Y-axis position detection coil 30B has an elongated loop shape having a linear portion extending in the X-axis direction, and the plurality of Y-axis position detection coils 30B are displaced in the Y-axis direction by a predetermined amount of overlap. It arrange | positions on the back side of the upper surface plate 21 so that it may become (d).

  In the position detection coil 30 of FIG. 5, the overlapping amount (d) between adjacent position detection coils 30 so as to overlap each other is set to 2/3 of the lateral width (W) of the elongated coil. In other words, the position detection coils 30 adjacent to each other are arranged so as to be displaced in the lateral width direction of the coil by 1/3 of the lateral width (W) of the coil. As shown in FIG. 7, the position detection coil 30 has an area where two adjacent position detection coils 30 overlap each other with 2/3 of each position detection coil 30 (hatching A and hatching B in FIG. 7). The area where the three position detection coils 30 adjacent to each other overlap each other is a 1/3 area of each position detection coil 30 (the common part of hatching A and hatching B in FIG. 7). In the illustrated position detection coil 30, the overlapping amount (d) between adjacent position detection coils 30 is 2/3 of the width (W) of the elongated coil, but the position detection coils are adjacent to each other so as to overlap each other. The overlap amount (d) between the position detection coils can be set to 1/2 to 9/10 of the lateral width (W) of the elongated coil.

  A position detection coil in which the overlap amount (d) between adjacent position detection coils so as to overlap each other is ½ of the lateral width (W) of the coil is not shown, but two adjacent position detection coils overlap each other. The area is a half of each position detection coil. A position detection coil in which the overlap amount (d) between adjacent position detection coils so as to overlap each other is 3/4 of the lateral width (W) of the coil is not shown, but two adjacent position detection coils are not shown. The overlapping area of each position detection coil becomes a 3/4 area, and the overlapping area of the three position detection coils adjacent to each other becomes a 2/4 area of each position detection coil, and the four position detections adjacent to each other. A region where the coils overlap is a quarter of each position detection coil.

  Further, the lateral width (W) of the position detection coil 30 is substantially equal to the outer diameter (D) of the power receiving coil 51, or is larger than the outer diameter (D), or is smaller than the outer diameter (D). doing. The position detection coil 30 can detect the position of the power receiving coil 51 with higher accuracy by increasing the overlap amount (d) between the adjacent position detection coils 30 so as to overlap each other.

  The detection pulse generation circuit 31 outputs a pulse signal to the position detection coil 30 at a predetermined timing. The position detection coil 30 to which the pulse signal is input excites the power receiving coil 51 that approaches with the pulse signal. The excited power receiving coil 51 outputs an echo signal to the position detection coil 30 with the energy of the flowing current. Therefore, as shown in FIG. 8, the position detection coil 30 near the power receiving coil 51 induces an echo signal from the power receiving coil 51 with a predetermined time delay after the pulse signal is input. The echo signal induced in the position detection coil 30 is output to the identification circuit 33 by the echo amplification circuit 32.

  The identification circuit 33 determines whether or not the power receiving coil 51 is approaching the position detection coil 30 based on the echo signal input from the echo amplification circuit 32. When echo signals are induced in the plurality of position detection coils 30, the identification circuit 33 determines that the position detection coil 30 with the highest echo signal level is closest.

  The position detection controller 14 shown in FIG. 5 connects each position detection coil 30 to the echo amplification circuit 32 via the multiplexer 34. The position detection controller 14 switches the input side of the echo amplification circuit 32 in order by the multiplexer 34 and connects it to the plurality of position detection coils 30. An echo signal can be detected. However, an echo amplifier circuit can be connected to each position detection coil to detect an echo signal.

  The position detection controller 14 in FIG. 5 switches the plurality of position detection coils 30 in order by the multiplexer 34 controlled by the identification circuit 33 and connects it to the echo amplification circuit 32. The detection pulse generation circuit 31 is connected to the input side of the echo amplification circuit 32, and sequentially outputs pulse signals to the position detection coil 30 via the multiplexer 34. The level of the pulse signal output from the detection pulse generation circuit 31 to the position detection coil 30 is extremely higher than the echo signal from the power receiving coil 51. The echo amplifier circuit 32 has a limiter circuit 35 made of a diode connected to the input side. The limiter circuit 35 limits the signal level of the pulse signal input from the detection pulse generation circuit 31 to the echo amplification circuit 32 and inputs it to the echo amplification circuit 32. The echo signal having a low signal level is input to the echo amplifier circuit 32 without being limited. The echo amplification circuit 32 amplifies and outputs both the pulse signal and the echo signal. The echo signal output from the echo amplifier circuit 32 is a signal delayed from the pulse signal by a predetermined timing, for example, several μsec to several hundred μsec. Since the delay time that the echo signal is delayed from the pulse signal is a fixed time, the signal after a predetermined delay time from the pulse signal is used as an echo signal, and the receiving coil 51 approaches the position detection coil 30 from the level of this echo signal. Determine whether or not.

  The echo amplification circuit 32 is an amplifier that amplifies an echo signal input from the position detection coil 30 and outputs the amplified echo signal to the identification circuit 33. The echo amplification circuit 32 outputs a pulse signal and an echo signal to the identification circuit 33. The echo amplification circuit 32 includes a gain adjustment circuit 37 that adjusts the amplification factor so that the echo signal is amplified linearly without being saturated. The echo amplification circuit 32 whose amplification factor is specified by the gain adjustment circuit 37 amplifies the echo signal input from the position detection coil 30 and inputs it to the identification circuit 33. The gain adjustment circuit 37 adjusts the amplification factor of the echo amplification circuit 32 so that the echo signal is output to the identification circuit 33 as a predetermined level.

  The gain adjustment circuit 37 does not change the amplification factor of the echo amplification circuit 32 every time an echo signal is detected. First, when the battery built-in device 50 is set on the top plate 21 of the charging base 10, the amplification factor of the echo amplification circuit 32 is set to an optimum value, and thereafter the echo signal is amplified without changing the amplification factor. Output to the identification circuit 33. The gain adjustment circuit 37 sets the amplification factor of the echo amplifying circuit 32 to an optimum value depending on the type of the battery built-in device 50, and is output from the power receiving coil 51 of the battery built-in device 50 to the BR position detection coil 30. This is to prevent the level of the echo signal from changing and the position of the power receiving coil 51 from being accurately detected. The echo amplification circuit 32 in which the amplification factor is set to the optimum value does not change the amplification factor of the echo amplification circuit 32 after that and is specified to the optimum amplification factor. Detect position. Therefore, after the battery built-in device 50 is set, the gain adjustment circuit 37 sets the amplification factor of the echo amplification circuit 32 to the optimum value, and then the identification circuit 33 receives the echo signal input from the echo amplification circuit 32. The position of the power receiving coil 51 is detected by the level. After the position is detected, the power transmission coil 11 is moved to the position of the power reception coil 51, power is transferred from the power transmission coil 11 to the power reception coil 51, and the battery 52 of the battery built-in device 50 is charged.

  The gain adjustment circuit 37 does not saturate the echo signal induced in the position detection coil 30, and amplifies the echo signal of a small level to an optimum level and inputs the gain to the discrimination circuit 33 so that the echo amplification circuit 32 Set the amplification factor. The level of the echo signal varies depending on the relative position between the power reception coil 51 and the position detection coil 30. In a state where the power receiving coil 51 is set at the center of the specific position detection coil 30, the level of the echo signal induced in the specific position detection coil 30 becomes maximum. Further, when the power receiving coil 51 is set across the two position detection coils 30, echo signals are output to the two position detection coils 30. The gain adjustment circuit 37 is placed on both sides of the position detection coil 30 where the echo amplification circuit 32 is not saturated with the maximum level echo signal induced in any one of the position detection coils 30 and the maximum level echo signal is induced. The amplification factor is set so that the sum of the levels of echo signals induced in the arranged position detection coils 30 is not saturated. The gain adjustment circuit 37 determines the amplification factor of the echo amplification circuit 32, the level of the echo signal that amplifies and outputs the maximum level echo signal, and the echo signal that is induced in the position detection coils 30 on both sides of the maximum level echo signal. The amplification factor of the echo amplifying circuit 32 is set so that both of the sums of the levels of echo signals that are amplified and output are within a set range with respect to the power supply voltage, for example, 3/4 of the power supply voltage. The gain adjustment circuit 37 can increase the setting range for specifying the level of the echo signal output from the echo amplification circuit 32 and can input a large level echo signal to the identification circuit 33. However, if the setting range of the output echo signal is increased, it becomes difficult for the echo amplification circuit 32 to amplify the echo signal linearly. On the contrary, if the setting range is reduced, the level of the echo signal input to the identification circuit 33 is reduced, and it becomes difficult for the identification circuit 33 to accurately detect the position of the power receiving coil 51. Therefore, the setting range in which the echo amplification circuit 32 outputs the echo signal, that is, the amplification factor of the echo amplification circuit 32 can linearly amplify the echo signal input to the echo amplification circuit 32, and the identification circuit 33 can It is set so that the position can be detected accurately.

  FIG. 9 shows a specific example of the echo amplification circuit 32 and the gain adjustment circuit 37. The echo amplifier circuit 32 in this figure includes a differential amplifier 38, and the gain adjustment circuit 37 inputs an amplification factor adjustment voltage to one input terminal of the differential amplifier 38 to adjust the amplification factor of the differential amplifier 38. Like to do. Further, the gain adjustment circuit 37 in this figure includes a voltage adjustment circuit 39 that smoothes a pulse signal output by PWM modulation from the identification circuit 33 and outputs a gain adjustment voltage. The voltage adjustment circuit 39 converts the pulse signal output by PWM modulation from the identification circuit 33 into a direct current by a smoothing circuit 40 including a resistor 41 and a capacitor 42 and inputs the direct current to the base of the transistor 43. The transistor 43 controls the negative feedback amount of the differential amplifier 38 by changing the voltage input to one terminal of the differential amplifier 38 by changing the electrical resistance between the collector and the emitter with the input voltage. Adjust the amplification factor.

  The identification circuit 33 calculates the duty of the pulse signal that is PWM-modulated and output from the level of the input echo signal. As described above, the identification circuit 33 specifies the duty of the pulse signal output by PWM modulation from the sum of the echo signal of the maximum level and the level of the echo signal induced in the position detection coils 30 on both sides thereof. The amplification factor of the echo amplifier circuit 32, that is, the amplification factor of the differential amplifier 38 is specified.

  The echo signal induced in the position detection coil 30 is input to the identification circuit 33 via the multiplexer 34. As shown in FIG. 10, the multiplexer 34 includes a switching element 34 </ b> A such as a transistor or FET that connects each position detection coil 30 to an identification circuit 33. The multiplexer 34 sequentially turns on the switching elements 34 </ b> A and inputs the echo signals induced in the position detection coils 30 to the identification circuit 33 in order. The switching element 34 </ b> A of the multiplexer 34 that inputs the echo signal of the position detection coil 30 to the identification circuit 33 has an electrical resistance in the on state. That is, there is an on-resistance. The on-resistance of the switching element 34 </ b> A becomes a factor that attenuates an echo signal input from the position detection coil 30 to the identification circuit 33. Furthermore, the on-resistance of each switching element 34A that configures the multiplexer 34, in other words, each switching element 34A that connects each position detection coil 30 to the identification circuit 33 is in an unbalanced state. For example, the switching element 34A of the multiplexer 34 has an unbalance of several tens of percent in on-resistance. The imbalance of the on-resistance of the switching element 34A varies the level of the echo signal input from the position detection coil 30 to the identification circuit 33. The switching element having a large on-resistance has a larger attenuation amount of the echo signal than the switching element having a low on-resistance, and lowers the level of the echo signal input to the identification circuit 33. Since the identification circuit 33 determines the position of the power receiving coil 51 from the level of the input echo signal, the level fluctuation of the echo signal caused by the multiplexer 34 causes an error in the position detection of the power receiving coil 51.

  In order to prevent this adverse effect, the charging stand 10 eliminates the imbalance of the internal resistance of each channel of the multiplexer 34 with the balance adjusting unit 44 shown in FIG. The balance adjustment unit 44 inputs the echo signal of the same level from each channel of the multiplexer 34 to the identification circuit 33 in a state in which the echo signal of the same level is induced in each position detection coil 30, and the internal resistance of each channel is calculated. Equalize unbalance due to differences. The balance adjustment unit 44 determines the level of the echo signal input via the switching element of the channel having a large ON resistance, that is, the channel having a large attenuation, and the level of the echo signal input via the switching element of the channel having the small attenuation. Is corrected to be larger than that, and the imbalance between channels of the multiplexer 34 is eliminated. The balance adjustment unit 44 sets the level of the echo signal input from the specific position detection coil 30 to the identification circuit 33 as a reference level, and the position of the identification circuit 33 from each position detection coil 30, that is, from each channel, relative to this reference level. The level of the echo signal input to is compared, and the imbalance between channels of the multiplexer 34 is corrected. Further, the balance adjustment unit 44 uses any one of the average value, the maximum value, and the minimum value of the echo signals input from the multiplexer 34 to the discrimination circuit 33 as a reference level, and the discrimination circuit 33 from each channel with respect to this reference level. The level of the echo signal input to is compared, and the imbalance between channels of the multiplexer 34 is eliminated. For example, the balance adjustment unit 44 corrects the level of the echo signal to which the identification circuit 33 is input 10% larger for a channel in which the level of the echo signal is 10% smaller than the reference level. That is, the balance adjustment unit 44 corrects the level of the input echo signal by applying a specific coefficient to the level of the echo signal input from each channel by the identification circuit 33 to eliminate the unbalance of each channel. To do. This coefficient can be detected by inputting an echo signal of the same level to all channels. A channel whose attenuation is large and the level of the echo signal input to the identification circuit 33 is small increases the coefficient, and the imbalance between the channels of the multiplexer 34 is eliminated.

  The balance adjustment unit 44 uses the power transmission coil 11 to input echo signals of the same level to each channel of the multiplexer 34. The balance adjustment unit 44 inputs a pulse signal to the position detection coil 30, excites the power transmission coil 11 with the input pulse signal, induces an echo signal from the excited power transmission coil 11 to the position detection coil 30, The same level of echo signal is induced in each channel of the multiplexer 34. In a state in which an echo signal is induced in the position detection coil 30, the power transmission coil 11 is not connected to the AC power supply 12, and a capacitor 45 constituting the resonance circuit 46 is connected to both ends thereof to constitute the resonance circuit 46. In order to induce the echo signals of the same level from the power transmission coils 11 to all the position detection coils 30, the power transmission coils 11 are moved to the center of each position detection coil 30, and the power transmission coils 11 are moved to the center. A pulse signal is output to the position detection coil 30 to induce an echo signal in the position detection coil 30.

  In order to move the power transmission coil 11 to the center of the position detection coil 30, the balance adjustment unit 44 includes a drive mechanism 47 that moves the power transmission coil 11 in the arrangement direction of the position detection coil 30. The balance adjusting unit 44 shown in the drawing also uses the moving mechanism 13 that moves the power transmission coil as the driving mechanism 47. The balance adjustment unit 44 controls the moving mechanism 13 that is the drive mechanism 47 to move the power transmission coil 11 in the arrangement direction of the position detection coils 30. Further, the balance adjustment unit 44 outputs a pulse signal from the position detection coil 30 to the power transmission coil 11. The power transmission coil 11 is excited by this pulse signal, and an echo signal is output from the excited power transmission coil 11 to the position detection coil 30. The level of the echo signal is detected, and unbalance due to the internal resistance of the multiplexer 34, that is, unbalance between channels of the multiplexer 34 is eliminated.

  The drive mechanism 47 of the balance adjustment unit 44 sequentially moves the power transmission coil 11 to the center of each position detection coil 30. The balance adjustment unit 44 stores the position of the power transmission coil 11. A pulse signal is output to the position detection coil 30 in which the power transmission coil 11 is disposed in the center. An echo signal is induced to the position detection coil 30 from the power transmission coil 11 excited by this pulse signal. The level of the echo signal is detected, and a coefficient for canceling the imbalance between channels of the multiplexer 34 is detected. The balance adjustment unit 44 sequentially moves the power transmission coil 11 to the center of each position detection coil 30, detects the attenuation amount of each channel of the multiplexer 34 connected to each position detection coil 30, and performs unbalance. Detect the coefficient to cancel. The balance adjustment unit 44 first detects a coefficient for correcting the imbalance between channels of the multiplexer 34, and then corrects the level of the echo signal induced in each channel by this coefficient, thereby determining the position of the power receiving coil 51. To detect.

  The identification circuit 33 includes an A / D converter 36 that converts a signal input from the echo amplification circuit 32 into a digital signal. The digital signal output from the A / D converter 36 is calculated to detect an echo signal. The identification circuit 33 detects a signal input after a specific delay time from the pulse signal as an echo signal, and further determines whether the power receiving coil 51 is approaching the position detection coil 30 from the level of the echo signal.

  The identification circuit 33 detects the position of the power receiving coil 51 in the X-axis direction by controlling the multiplexer 34 so that the plurality of X-axis position detection coils 30 </ b> A are sequentially connected to the echo amplification circuit 32. The identification circuit 33 outputs a pulse signal to the X-axis position detection coil 30A connected to the identification circuit 33 every time each X-axis position detection coil 30A is connected to the echo amplification circuit 32, and a specific signal is identified from the pulse signal. It is determined whether or not the power receiving coil 51 is approaching the X-axis position detection coil 30A based on whether or not an echo signal is detected after the delay time. The identification circuit 33 connects all the X-axis position detection coils 30A to the echo amplification circuit 32, and determines whether or not the power receiving coil 51 is close to each X-axis position detection coil 30A. When the power receiving coil 51 approaches one of the X-axis position detection coils 30A, an echo signal is detected in a state where the X-axis position detection coil 30A is connected to the echo amplification circuit 32. Therefore, the identification circuit 33 can detect the position of the power receiving coil 51 in the X-axis direction from the X-axis position detection coil 30A that can detect an echo signal. In a state in which the power receiving coil 51 approaches across the plurality of X-axis position detection coils 30A, echo signals are detected from the plurality of X-axis position detection coils 30A. In this state, the identification circuit 33 determines the position of the power receiving coil 51 in the X-axis direction from the level of echo signals induced in the plurality of X-axis position detection coils 30A. Further, the identification circuit 33 similarly controls the Y-axis position detection coil 30B to detect the position of the power receiving coil 51 in the Y-axis direction.

  The identification circuit 33 controls the moving mechanism 13 from the position in the X axis direction and the position in the Y axis direction to be detected, and moves the power transmission coil 11 to a position approaching the power reception coil 51. The identification circuit 33 controls the X-axis servomotor 22 </ b> A of the moving mechanism 13 to move the power transmission coil 11 to the position of the power reception coil 51 in the X-axis direction. Further, the Y-axis servomotor 22B of the moving mechanism 13 is controlled to move the power transmission coil 11 to the position of the power reception coil 51 in the Y-axis direction.

  As described above, the position detection controller 14 moves the power transmission coil 11 to a position approaching the power reception coil 51. The charging stand of the present invention can charge the battery 52 by transferring power from the power transmission coil 11 to the power reception coil 51 after the power transmission coil 11 approaches the power reception coil 51 by the position detection controller 14. However, the charging stand further accurately controls the position of the power transmission coil 11 to approach the power receiving coil 51, and then transports power to charge the battery 52.

  Further, the position detection controller 64 shown in FIG. 11 causes the identification circuit 73 to detect the level of the echo signal induced in each position detection coil 30 with respect to the position of the power receiving coil 51, that is, each position as shown in FIG. A memory circuit 77 is provided for storing the level of an echo signal that is induced after a predetermined time has elapsed by exciting the detection coil 30 with a pulse signal. The position detection controller 64 detects the level of the echo signal induced in each position detection coil 30, compares the level of the detected echo signal with the level of the echo signal stored in the storage circuit 77, and The position of the power receiving coil 51 is detected.

  The position detection controller 64 obtains the position of the power receiving coil 51 from the level of the echo signal induced in each position detection coil 30 as follows. FIG. 12 shows the level of the echo signal induced in the X-axis position detection coil 30A in a state where the power receiving coil 51 is moved in the X-axis direction, and the horizontal axis shows the position of the power receiving coil 51 in the X-axis direction. The vertical axis indicates the level of the echo signal induced in each X-axis position detection coil 30A. The position detection controller 64 detects the level of the echo signal induced in each X-axis position detection coil 30A, and obtains the position of the power receiving coil 51 in the X-axis direction. As shown in this figure, when the power receiving coil 51 is moved in the X-axis direction, the level of the echo signal induced in each X-axis position detection coil 30A changes.

  For example, when the power receiving coil 51 is in the middle of the first X-axis position detection coil 30A and the second X-axis position detection coil 30A, as shown by a point a in FIG. 12, the first X-axis position detection coil 30A. And the level of the echo signal induced in the second X-axis position detection coil 30A is the maximum and the same. Further, when the power receiving coil 51 is at a position deviated from the middle between the first X-axis position detection coil 30A and the second X-axis position detection coil 30A, the first X-axis position detection coil 30A and the second X-axis position The level ratio of the echo signal induced in the detection coil 30A changes. Therefore, the position of the power receiving coil 51 can be detected from the level ratio of echo signals induced in the first X-axis position detection coil 30A and the second X-axis position detection coil 30A.

  Furthermore, when the power receiving coil 51 is in the center of the second X-axis position detection coil 30A, that is, in the region A in FIG. 12, the level of the echo signal induced in the second X-axis position detection coil 30A is , Become the strongest. However, when the power receiving coil 51 is in the A region, the level variation of the echo signal with respect to the movement distance of the power receiving coil 51 in the X-axis direction is small, and the level of the echo signal varies depending on other factors. When 51 is in the A region, if the position of the power receiving coil 51 is determined only by the level of the echo signal induced in the second X-axis position detection coil 30A, it cannot be accurately determined. Therefore, when the identification circuit 33 is in this region, the first X-axis position detection coil 30A and the third X-axis position detection coil as well as the echo signal induced by the second X-axis position detection coil 30A The position of the power receiving coil 51 is also determined from the level of the echo signal induced by 30A. When the power receiving coil 51 is located at the center of the second X-axis position detection coil 30A, the levels of the echo signals induced in the first X-axis position detection coil 30A and the third X-axis position detection coil 30A are equal. Alternatively, the level of the echo signal becomes 0 level. Accordingly, the identification circuit 33 is applied to the first X-axis position detection coil 30A and the third X-axis position detection coil 30A in a state where the echo signal induced in the second X-axis position detection coil 30A is at the maximum level. If the levels of the induced echo signals are equal or both are 0 level, it is determined that the power receiving coil 51 is located at the center of the second X-axis position detection coil 30A. When the position of the power receiving coil 51 is slightly shifted from the center portion of the second X-axis position detection coil 30A, an echo signal that is induced in the first X-axis position detection coil 30A and the third X-axis position detection coil 30A. The level of changes. When the power receiving coil 51 is displaced toward the first X-axis position detection coil 30A, the level of the echo signal induced in the first X-axis position detection coil 30A is induced in the third X-axis position detection coil 30A. It becomes larger than the level of the echo signal. Therefore, in this state, the identification circuit 33 accurately detects the position of the power receiving coil 51 from the level ratio of echo signals induced in the first X-axis position detection coil 30A and the second X-axis position detection coil 30A. can do. This is because as the power receiving coil 51 moves toward the first X-axis position detection coil 30A, the level of the echo signal induced in the first X-axis position detection coil 30A increases. On the other hand, when the power receiving coil 51 is shifted to the third X-axis position detection coil 30A side, the level of the echo signal induced in the third X-axis position detection coil 30A is changed to the first X-axis position detection coil 30A. It becomes larger than the level of the induced echo signal. Therefore, in this state, the identification circuit 33 can accurately detect the position 51 of the power receiving coil from the level ratio of echo signals induced in the second and third X-axis position detecting coils 30A. This is because as the power receiving coil 51 moves toward the third X-axis position detection coil 30A, the level of the echo signal induced in the third X-axis position detection coil 30A increases.

  As described above, the identification circuit 33 does not determine the position of the power receiving coil 51 only from the echo signal of the position detection coil 30 at the maximum level in a state where the echo signal is at the maximum level. The position of the power receiving coil 51 is determined in consideration of echo signals induced in the position detection coils 30 on both sides of the position detection coil 30 that detects the maximum level echo signal. Accordingly, the position of the power receiving coil 51 in the area A, which is the central portion of the position detection coil 30, can accurately detect even a slight deviation from the center of the position detection coil 30 at the maximum level.

  The identification circuit 73 stores the level and level ratio of the echo signal induced in each X-axis position detection coil 30 </ b> A with respect to the position of the power receiving coil 51 in the X-axis direction in the storage circuit 77. When the power receiving coil 51 is placed, an echo signal is induced in one of the X-axis position detection coils 30A. Therefore, the identification circuit 73 detects that the power receiving coil 51 has been placed by an echo signal induced in the X-axis position detection coil 30 </ b> A, that is, that the battery built-in device 50 has been placed on the charging stand 10. Further, the level and level ratio of the echo signal induced in one of the X-axis position detection coils 30 </ b> A is compared with the level and level ratio stored in the storage circuit 77, and the position of the power receiving coil 51 in the X-axis direction. Is accurately determined.

  The above shows a method in which the identification circuit 73 detects the position of the power receiving coil 51 in the X-axis direction from the echo signal induced in the X-axis position detection coil 30A, but the position of the power receiving coil 51 in the Y-axis direction is also X. In the same manner as in the axial direction, it can be detected from the echo signal induced in the Y-axis position detection coil 30B.

When the identification circuit 73 detects the positions of the power receiving coil 51 in the X-axis direction and the Y-axis direction, the position detection controller 64 moves the power transmission coil 11 to the position of the power receiving coil 51 with the position signal from the identification circuit 73. Let
When the echo signal having the waveform as described above is detected, the identification circuit 73 of the charging stand can recognize and identify that the power receiving coil 51 of the battery built-in device 50 is mounted. When a waveform different from the waveform of the echo signal is detected and identified, the power supply can be stopped assuming that a device other than the power receiving coil 51 (for example, a metal foreign object) of the battery built-in device 50 is mounted. When the waveform of the echo signal is not detected or identified, the power supply coil 51 of the battery built-in device 50 is not mounted and power is not supplied.

  The charging stand 10 supplies AC power to the power transmission coil 11 with the AC power source 12 in a state where the position detection controllers 14 and 64 control the moving mechanism 13 to bring the power transmission coil 11 closer to the power reception coil 51. The AC power of the power transmission coil 11 is transferred to the power reception coil 51 and used for charging the battery 52. When the battery built-in device 50 detects that the battery 52 is fully charged, it stops charging and transmits a full charge signal to the charging stand 10. The battery built-in device 50 can output a full charge signal to the power receiving coil 51, transmit this full charge signal from the power receiving coil 51 to the power transmission coil 11, and transmit full charge information to the charging stand 10. The battery built-in device 50 outputs an AC signal having a frequency different from that of the AC power source 12 to the power receiving coil 51, and the charging stand 10 can receive the AC signal by the power transmitting coil 11 and detect full charge. Further, the battery built-in device 50 outputs a signal that modulates a carrier wave of a specific frequency with a full charge signal to the power receiving coil 51, and the charging stand 10 receives the carrier wave of a specific frequency and demodulates this signal to detect a full charge signal. You can also Furthermore, the battery built-in device can also transmit full charge information by wirelessly transmitting a full charge signal to the charging stand. The battery built-in device has a built-in transmitter that transmits a full charge signal, and the charging stand has a built-in receiver that receives the full charge signal. The position detection controller 14 shown in FIG. 6 incorporates a full charge detection circuit 17 that detects the full charge of the built-in battery 52. The full charge detection circuit 17 detects a full charge signal output from the battery built-in device 50 to detect full charge of the battery 52.

  The charging stand 10 on the top plate 21 on which the plurality of battery built-in devices 50 can be placed switches the batteries 52 of the plurality of battery built-in devices 50 in order and is fully charged. The charging stand 10 first detects the position of the power receiving coil 51 of any of the battery built-in devices 50, makes the power transmitting coil 11 approach the power receiving coil 51, and fully charges the battery 52 of the battery built-in device 50. To do. When the battery 52 of the battery built-in device 50 is fully charged and the full charge detection circuit 17 receives the full charge signal, the position detection controller 14 is set to a second position different from the battery built-in device 50. The position of the power receiving coil 51 of the battery built-in device 50 is detected, and the moving mechanism 13 is controlled to bring the power transmitting coil 11 closer to the power receiving coil 51 of the second battery built-in device 50. In this state, power is transferred to the battery 52 of the second battery-equipped device 50, and the battery 52 is fully charged. Further, when the battery 52 of the second battery built-in device 50 is fully charged and the full charge detection circuit 17 receives the full charge signal from the second battery built-in device 50, the position detection controller 14 further performs the third operation. The power receiving coil 51 of the battery built-in device 50 is detected, the moving mechanism 13 is controlled to bring the power transmission coil 11 close to the power receiving coil 51 of the third battery built-in device 50, and the battery 52 of the battery built-in device 50 is moved. Fully charge. As described above, when the plurality of battery built-in devices 50 are set on the top plate 21, the battery built-in devices 50 are sequentially switched to fully charge the built-in battery 52. The charging stand 10 stores the position of the fully-charged battery built-in device 50 and does not charge the battery 52 of the fully-charged battery built-in device 50. When it is detected that the batteries 52 of all the battery built-in devices 50 set on the top plate 21 are fully charged, the charging stand 10 stops the operation of the AC power supply 12 and stops the charging of the batteries 52. Here, in the above embodiment, the charging is stopped when the battery 52 of the battery built-in device 50 is fully charged. However, the charging may be stopped when the battery 52 reaches a predetermined capacity. .

  The above moving mechanism 13 moves the power transmission coil 11 in the X-axis direction and the Y-axis direction to move the power transmission coil 11 to a position closest to the power receiving coil 51. In the present invention, the movement mechanism is in the X-axis direction. The power transmission coil is moved in the Y-axis direction and the position of the power transmission coil is not specified as a structure for approaching the power reception coil, and the power transmission coil can be moved in various directions to approach the power reception coil.

  The charging stand according to the present invention can be suitably used not only for charging a mobile phone or a portable music player, but also for charging an assist bicycle or an electric vehicle.

DESCRIPTION OF SYMBOLS 10 ... Charging stand 11 ... Power transmission coil 12 ... AC power supply 13 ... Moving mechanism 14 ... Position detection controller 15 ... Core 15A ... Cylindrical part
15B ... Cylindrical part 16 ... Lead wire 17 ... Full charge detection circuit 20 ... Case 21 ... Top plate 22 ... Servo motor 22A ... X-axis servo motor
22B ... Y-axis servo motor 23 ... Screw rod 23A ... X-axis screw rod
23B ... Y-axis screw rod 24 ... Nut material 24A ... X-axis nut material
24B ... Y-axis nut material 25 ... Belt 26 ... Guide rod 27 ... Guide part 30 ... Position detection coil 30A ... X-axis position detection coil
30B ... Y-axis position detection coil 31 ... Detection pulse generation circuit 32 ... Echo amplification circuit 33 ... Identification circuit 34 ... Multiplexer 34A ... Switching element 35 ... Limiter circuit 36 ... A / D converter 37 ... Gain adjustment circuit 38 ... Differential amplifier 39 ... voltage adjustment circuit 40 ... smoothing circuit 41 ... resistor 42 ... capacitor 43 ... transistor 44 ... balance adjustment unit 45 ... capacitor 46 ... resonance circuit 47 ... drive mechanism 50 ... battery built-in device 51 ... power receiving coil 52 ... battery 53 ... capacitor 54 ... Parallel resonant circuit 55 ... Diode 56 ... Smoothing capacitor 57 ... Rectifier circuit 58 ... Charge control circuit 64 ... Position detection controller 73 ... Identification circuit 77 ... Storage circuit 130 ... Position detection coil 130A ... X-axis position detection coil 151 ... Receiving coil

Claims (8)

A charging stand for a battery built-in device (50) including a battery (52) to be charged with power carried by the power receiving coil (51),
A power transmission coil (11) connected to the AC power source (12) and carrying the electromotive force to the power reception coil (51), and the power transmission coil (11) are incorporated, and a battery built-in device (50) is provided on the upper surface. A case (20) having an upper surface plate (21) to be mounted, and a moving mechanism (13) built in the case (20) to move the power transmission coil (11) along the inner surface of the upper surface plate (21); The position of the power receiving coil (51) of the battery built-in device (50) placed on the upper surface plate (21) is detected and the moving mechanism (13) is controlled so that the power transmitting coil (11) becomes the power receiving coil (51). A charging stand comprising a position detection controller (14; 64) to be approached,
The position detection controller (14; 64) has a plurality of position detection coils (30) arranged at predetermined intervals on the back side of the upper surface plate (21), and pulses as position detection signals to the position detection coil (30). A detection pulse generator circuit (31) for supplying a signal, and a pulse signal supplied from the detection pulse generator circuit (31) to the position detection coil (30) and excited by a pulse signal from the power reception coil (51) to the position detection coil (30) An echo amplifier circuit (32) for receiving the echo signal induced by the signal, and an identification circuit (33) for determining the position of the power receiving coil (51) from the echo signal output from the echo amplifier circuit (32),
The echo amplification circuit (32) includes a gain adjustment circuit (37) for adjusting an amplification factor so as to linearly amplify an echo signal input from the position detection coil (30) without being saturated. A charging base in which the echo amplification circuit (32) whose amplification factor is specified in (37) amplifies the echo signal input from the position detection coil (30) and inputs it to the identification circuit (33).   The echo amplification circuit (32) includes a differential amplifier (38), and the gain adjustment circuit (37) inputs an amplification factor adjustment voltage to one input terminal of the differential amplifier (38), and the differential amplifier ( The charging stand according to claim 1, wherein the amplification factor of 38) is adjusted.   The gain adjustment circuit (37) includes a voltage adjustment circuit (39) for smoothing a signal output by PWM modulation and outputting a gain adjustment voltage, and the gain adjustment voltage output from the voltage adjustment circuit (39) 3. The charging stand according to claim 2, wherein is input to one input terminal of the differential amplifier (38) to adjust the amplification factor of the differential amplifier (38).   Each position detection coil (39) is provided with a multiplexer (34) for sequentially connecting the detection pulse generation circuit (31) and the echo amplification circuit (32), and the internal resistance of the multiplexer (34) is unbalanced. The charging stand according to any one of claims 1 to 3, further comprising a balance adjusting unit (44) for canceling.   The balance adjusting unit (44) has a drive mechanism (47) for moving the power transmission coil (11) in the arrangement direction of the position detection coil (30), and outputs from the position detection coil (30) to the power transmission coil (11). 5. The level of the echo signal output from the power transmission coil (11) to the position detection coil (30) is detected with the pulse signal generated to cancel the imbalance due to the internal resistance of the multiplexer (34). Charging stand.   The drive mechanism (47) moves the power transmission coil (11) to the center of each position detection coil (30), and the balance adjustment unit (44) has an echo signal from the power transmission coil (11), 6. The charging stand according to claim 5, which eliminates an imbalance in the internal resistance of the multiplexer (34). The position detection coil (30) is disposed so as to overlap a part of the position detection coil (30) adjacent to the position detection coil (30),
The identification circuit (33) includes a position detection coil (30) from which an echo signal of the maximum level is induced, and a receiving coil (51) from the level of the echo signal of the position detection coil (30) disposed on both sides thereof. The charging stand according to claim 1, wherein the position is determined. The position detection coil (30) is an elongated coil having a straight portion, and the adjacent position detection coil (30) is arranged so as to be displaced in a direction perpendicular to the longitudinal direction of the coil,
The charging stand according to claim 7, wherein the overlapping amount (d) of the position detecting coils (30) adjacent to each other so as to overlap each other is 1/2 to 9/10 of the lateral width (W) of the elongated coil.