JP2014165967A - Power transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which a moving coil type power transmitter requires a movement mechanism such as a motor and a complex algorithm for alignment and a multicoil type power transmitter uses a plurality of power transmission coils, which makes a configuration complex and increases a price of the power transmitter higher, as a result.SOLUTION: The power transmitter that supplies a power receiver with power by electromagnetic induction using a power transmission coil includes: a main body having a placing face on a top surface; and a guide bar that is disposed on the placing face and is movable on the placing face.

Description

  The present invention relates to a power transmitter that transmits electric power to a power receiver in a contactless manner using electromagnetic induction.

Wireless charging that transmits power in a contactless manner to electronic device terminals such as mobile phones has become widespread. In wireless charging, electromagnetic induction is generated between a power transmission coil built in a power transmitter and a power reception coil built in a power receiver such as an electronic device terminal, thereby performing power transmission without contact. The power transmitted to the power receiving coil is supplied to a load such as a secondary battery built in the power receiver via the rectifier circuit.
Wireless charging is convenient because charging can be performed simply by placing the power receiver on the power transmitter, and it is not necessary to connect or disconnect the power connector. Furthermore, since there is no need to provide a power connector for charging, there is an advantage that it is easy to add a waterproof function and a dustproof function to the power receiver.

In recent years, a general-purpose wireless charging standard that enables various power receivers to be charged by a single power transmitter, for example, a WPC (Wireless Power Consortium) standard (hereinafter referred to as a WPC standard) has been standardized.
In general, since wireless charging improves the efficiency of power transmission from a power transmitter to a power receiver, it is necessary to accurately align the positions of the power transmitting coil and the power receiving coil. In the case of a dedicated power transmitter with a one-to-one relationship between the power receiver and the power transmitter, there is no need for alignment if the power transmitter and the power receiver are shaped so that they fit together. In some cases, a single power transmitter must handle a wide variety of power receivers having various shapes. As a method for realizing this, a moving coil system that detects the position of the power receiving coil and moves the power transmitting coil close to the power receiving coil by a moving mechanism provided in the power transmitter, or a part of the power transmitting coil overlaps. A multi-coil system or the like has been proposed in which power is transmitted by arranging only tiles in a tiled manner and driving only a power transmission coil near the power receiving coil (see Patent Document 1 and Patent Document 2).

JP 2010-263663 A JP 2012-110135 A

  However, the moving coil system described above requires a moving mechanism such as a motor and a complicated algorithm for alignment. In addition, since the multi-coil method uses a plurality of power transmission coils, the configuration of the power transmitter becomes complicated. As a result, there is a problem that the price of the power transmitter becomes high. This high price hindered the spread of general-purpose power transmitters.

  The power transmitter of the present invention has been made in view of the above problems, and includes a main body having a mounting surface on an upper surface, and a guide bar that is disposed on the mounting surface and is movable on the mounting surface. It is characterized by.

  The power transmitter of the present invention can align the power transmission coil and the power receiving coil with a simple configuration, reduce the member cost, and provide an inexpensive power transmitter.

It is a perspective view which shows the 1st Example of the power transmission device of this invention. It is the top view and front view of FIG. It is a flowchart of alignment of the power transmission device of this invention. It is a figure explaining the procedure of alignment of the power transmission device of this invention. It is a graph of the signal strength with respect to the position of a guide bar. It is a perspective view which shows the 2nd Example of the power transmission device of this invention. It is a perspective view which shows the 3rd Example of the power transmission device of this invention. It is a perspective view which shows the 4th Example of the power transmission device of this invention.

Example 1
Hereinafter, a first embodiment of a power transmitter according to the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is a perspective view showing a usage state of a power transmitter according to a first embodiment of the present invention, FIG. 2 (a) shows a plan view of the power transmitter, and FIG. 2 (b) shows a front view. As shown in FIGS. 1 and 2, the power transmitter 10 includes a main body 20 with a built-in power transmission coil and a guide bar 30.

  The main body 20 of the power transmitter 10 is provided with a switch 60, a flat and rectangular mounting surface 21 on the upper surface, and grooves 22 on both side surfaces. The mounting surface 21 is provided with an LED 50 for notifying the state of the power transmitter 10. The guide bar 30 is formed in a U shape so as to be able to hold the mounting surface 21 and the side surface of the main body 20, and at a position facing the grooves 22 provided on both side surfaces of the main body 20 on the inner side surface. A convex portion 33 is provided. The guide bar 30 is attached to the main body 20 so that the convex portion 33 can be moved on the mounting surface 21 by fitting with the grooves 22 provided on both side surfaces of the main body 20. Further, the position of the guide bar 30 can be fixed to the main body 20 by using a screw 70 provided on the guide bar 30.

  In addition, a planar power transmission coil 40 in which a conductive wire with an insulating coating is wound in a spiral shape is incorporated inside the main body 20 so as to be positioned at the center of the mounting surface 21. In order to reduce the increase in resistance value due to the skin effect, the power transmission coil 40 often uses a litz wire in which a plurality of conductive wires with insulating coatings are wound together. When charging the power receiver 80 using the power transmitter 10 formed in this way, the power receiver 80 including the power receiving coil 81 is mounted on the mounting surface 21.

In such a power transmitter 10, in order to detect the position of the power receiving coil, the strength of the signal transmitted from the power receiver is measured in the power transmitter. As a measuring method, there are a method based on the WPC standard and a method using an echo signal from the power receiving coil.
For example, in the method based on the WPC standard, initial power required for the operation of the control system of the power receiver is transmitted from the power transmitter to the power receiver, and the power receiver receives data obtained by digitizing the rectified voltage value of the power receiver within 100 ms. Is modulated as a signal intensity and transmitted to the power transmitter as signal strength. By intermittently transmitting power from the power transmitter to the power receiver, the signal strength from the power receiver can be continuously received and measured. Further, for example, in the method using an echo signal, an excitation coil for intermittently transmitting a pulse signal to the power receiver is arranged in the vicinity of the power transmission coil, and is generated by a current induced in the power reception coil with respect to the pulse signal by the excitation coil. The transmitter receives the echo signal as signal strength and measures it. In addition to the above method, various methods can be used for measuring the signal intensity for detecting the position of the power receiving coil.

Hereinafter, the alignment procedure will be described with reference to FIGS. FIG. 3 is a flowchart showing the alignment procedure, and FIG. 4 is a diagram for explaining each state. In FIG. 3, the positions of the power transmission coil 40 and the power reception coil 81 are indicated by dotted lines, the same numbers are assigned to the same parts in FIGS. 1 and 2, and descriptions thereof are omitted.
(1) As shown in FIG. 4A, the guide bar 30 of the power transmitter 10 operating in the normal operation mode is moved to the one end A side of the placement surface 21, and the guide bar 30 and the power receiver 80 are moved. Place in contact. The position of the guide bar 30 at this time is y = y0.
(2) When the switch 60 is operated, the power transmitter 10 changes the operation to the peak hold mode in which the signal intensity from the power receiver 80 is measured and the maximum value is continuously updated. Notify the change of the operation mode. In the peak hold mode, the signal strength P is continuously measured. When the signal strength P is larger than the maximum signal strength Pmax so far, the signal strength P is set as a new maximum signal strength Pmax, and the maximum signal strength is reached. Continue to update the value Pmax.
(3) As shown in FIGS. 4B to 4C, the guide bar 30 and the power receiver 80 are in contact with each other, and slowly move from one end A side to the other end B side of the mounting surface 21. To do. FIG. 4B shows a state in which the positions of the power transmission coil 40 and the power reception coil 81 are substantially the same. The position of the guide bar 30 at this time is y = y1, and FIG. 4C shows the state of FIG. And the position of the guide bar 30 at this time is y = y2. When the guide bar 30 is moved to the other end B side, the final value of the maximum value Pmax of the signal intensity is obtained.
(4) When the switch 60 is operated again, the power transmitter 10 changes the operation to the compare mode, and notifies the change of the operation mode of the power transmitter 10 by blinking or lighting of the LED 50. Similarly to the peak hold mode, the compare mode also measures the signal strength P continuously, but differs from the peak hold mode in that the maximum value Pmax of the signal strength is compared with the current signal strength P.
(5) As shown in FIG. 4D, in the state where the guide bar 30 and the power receiver 80 are in contact with each other, the signal bar P is moved slowly from the other end B side which is the opposite direction to the one end A side. Is substantially equal to the maximum value Pmax of the signal intensity, the fact that the position of the guide bar 30 is in the optimum position is notified by blinking or lighting of the LED 50. Here, the movement is immediately stopped and the position of the guide bar 30 is fixed with the screw 70.
(6) When the switch 60 is operated again, the power transmitter changes the operation to the normal operation mode, and notifies the change of the operation mode of the power transmitter 10 by blinking or lighting of the LED 50.
This completes the alignment procedure.

FIG. 5 is a graph showing the position of the guide bar and the signal intensity. In FIG. 5, the horizontal axis indicates the position y of the guide bar, and the vertical axis indicates the signal intensity P.
From FIG. 5, it can be seen that when the position of the guide bar is y1, the maximum value Pmax of the signal strength is obtained. Therefore, if the guide bar is moved to the position y1 where the maximum value of signal strength Pmax is obtained, The position with the receiving coil can be made to substantially coincide.

  In the above-described embodiment, the position can be adjusted only in the direction in which the guide bar moves. However, the power receiver is often rectangular, and the position of the power receiving coil built into the power receiver is not necessarily the center of the power receiver in the longitudinal direction due to design reasons, but is limited in space in the short direction. Even if there is a deviation from the center of the power receiver, the deviation amount is limited. In such a power receiver, the effect of the shift in the short direction on the efficiency of power transmission is small, and the movement direction of the guide bar is the longitudinal direction of the power transmitter, and only the position in the longitudinal direction is adjusted, so Even without adjusting the position of the direction, the power receiving coil and the power transmitting coil can be brought close to each other, and power can be transmitted.

  Thus, the maximum value of the signal intensity obtained by moving the power receiver together with the guide bar on the entire mounting surface, and the signal obtained sequentially by moving the power receiver together with the guide bar on the mounting surface. By comparing the strength, the power transmission coil and the power reception coil can be aligned with a simple configuration that does not use a mechanical component such as a motor. As a result, an inexpensive power transmitter can be obtained. The alignment described above does not need to be performed every time charging is performed, but may be performed only once for charging another type of power receiver.

(Example 2)
In the first embodiment, the power receiver may deviate from the direction orthogonal to the direction of movement of the guide bar. FIG. 6 is a perspective view showing a power transmitter 11 according to the second embodiment. As shown in FIG. 6, a biasing member 35 is provided on the guide bar 31 so that the power receiver is located in the center direction in the direction orthogonal to the moving direction of the guide bar 31. With such a configuration, the power receiver can be held at the center of the placement surface 21, and displacement in a direction orthogonal to the guide bar can be prevented.

  In the second embodiment as well, it is considered that the position of the power receiving coil is arranged substantially at the center with respect to the short direction of the power receiver. Therefore, the moving direction of the guide bar is the longitudinal direction of the power transmitter, only the position in the longitudinal direction is adjusted, and the position adjustment in the short direction is only to place the power receiver at the approximate center in the short direction. The power receiving coil and the power transmitting coil can be brought closer to each other than in the first embodiment, and the power can be transmitted more efficiently.

(Example 3 to Example 4)
In the first embodiment, since the position of the guide bar is fixed with a screw, it is necessary to tighten or loosen the screw each time the guide bar is moved, which is troublesome. FIG. 7 is a perspective view showing a power transmitter 12 according to the third embodiment. As shown in FIG. 7, the power transmitter 12 includes a fixing tool such as a screw by the arm portion 34 provided at the tip of the guide bar 32 coming into contact with the wave-like portions 23 provided on both longitudinal sides of the main body 21. Even without using, the position of the guide bar 32 can be easily fixed.
Moreover, as shown in FIG. 8, the mounting surface 20 may be inclined. FIG. 8 is a perspective view showing a power transmitter 13 according to the fourth embodiment. Since the mounting surface 21 is inclined, the power transmitter 13 can be easily moved in a state where the power receiver and the guide bar 31 are in close contact with each other.

  Note that the LED and the switch are not limited to the above-described embodiments. The place to be arranged is not limited to the placement surface, and a plurality of switches or a plurality of LEDs may be arranged. Further, the method of blinking or lighting the LED may be changed as appropriate so that the state of each mode is easy to understand, and may be used as a display for informing the charging state in the normal operation mode. Sound or vibration may be used or displayed on a display.

10, 11, 12, 13 Power transmitter 20 Main body 21 Placement surface 22 Groove 23 Wave-shaped part 30, 31, 32 Guide bar 33 Projection part 34 Arm part 35 Energizing member 40 Power transmission coil 50 LED
60 switch 70 screw 80 power receiver 81 power receiving coil

Claims (5)

In a power transmitter that supplies power to a power receiver by electromagnetic induction using a power transmission coil,
A main body having a mounting surface on the upper surface;
A guide bar disposed on the placement surface and movable on the placement surface;
A power transmitter characterized by comprising: The power transmitter according to claim 1, further comprising notification means for notifying an optimal position of the guide bar based on the signal strength received from the power receiver. The optimal position is
The maximum value of the signal intensity from the power receiver obtained by the first step of moving the power receiver together with the guide bar over the mounting surface;
The signal strength received from the power receiver sequentially obtained by the second step of moving the power receiver together with the guide bar on the mounting surface,
The power transmission device according to claim 2 obtained by comparing. The power transmitter according to claim 3, wherein the guide bar includes a biasing member that biases toward the center of the placement surface. The power transmitter according to claim 4, wherein the mounting surface is inclined.

Images