JP5805576B2 - Resonant type wireless power transmission device - Google Patents

Description

  The present invention relates to a resonance type wireless power transmission apparatus that feeds power from a power transmission side device outside a manhole to a power reception side device in a manhole by an electromagnetic induction method and communicates between the power transmission side device and the power reception side device by an electromagnetic induction method. About.

  A power feeding method that does not require a wired connection is used for charging a secondary battery such as a mobile phone or supplying power to a non-contact IC card, an RFID tag, or the like. This is based on the electromagnetic induction method, and coils are arranged on the power transmission side and the power reception side, and the power is transmitted to the power reception side when they are close to each other and the magnetic flux of the power transmission side coil passes through the power reception side coil ( Non-patent document 1). In general, in order to obtain a sufficient transmission efficiency, the electromagnetic induction method is a method in which the transmitting and receiving coils are close to each other to reduce the leakage magnetic flux. Furthermore, in recent years, a resonance-type wireless power transmission apparatus has been proposed that can obtain high power supply efficiency even when a certain transmission distance (for example, 2 to 3 m) is provided (Non-Patent Document 2).

FIG. 14 shows a configuration example of a resonance type wireless power transmission apparatus.
In FIG. 14, a power transmission side coil 13 connected to the power source 11 of the power transmission side device 10 and a power reception side coil 22 connected to the load 23 of the power reception side device 20 are respectively connected to the power transmission side resonance coil 14 and the power reception side resonance coil 21. The electric power is transmitted from the power source 11 to the load 23 by being electrically coupled by electromagnetic induction through a resonance phenomenon. Resonance occurs only at specific frequencies. FIG. 15 shows an example of the S parameter (S21) of the resonance coil. From the figure, it can be seen that the frequency at which the peak is obtained is limited, and that the peak frequency varies depending on the load. Further, the peak frequency varies depending on the interval between the power transmission side device 10 and the power reception side device 20. Furthermore, as shown in FIG. 16, the received power peak value varies according to the distance between the power transmitting and receiving coils, and there is an optimum distance.

  By the way, if the sensor information collected in the manhole can be collected by transmitting the sensor information etc. using the power supplied by the above-mentioned resonance type wireless power transmission device without opening the lid of the entrance / exit of the manhole, Maintenance work is greatly simplified.

Hiroshi Isobe, “Introduction to contactless IC card design”, Nikkan Kogyo Shimbun. Aristeidis Karalis, J.D.Joannopoulos and Marin Soljacic, 'Efficient wireless non-radiative mid-range energy transfer,' Annals of Physics, Vol.323 Issue 1, pp.34-48, Apr 2007.

  In the resonance type wireless power transmission apparatus shown in FIG. 14, when the power supply frequency on the power transmission side is set to a frequency different from the resonance frequency, sufficient power does not reach the power reception side. In addition, when the power frequency on the power transmission side is significantly different from the resonance frequency, if transmission data is transmitted from the power receiving side by load modulation that changes the load impedance on the power receiving side, the load impedance of the power receiving side on the power transmission side A change in current or voltage due to the change cannot be detected, and uplink information transmission fails. For example, even if an attempt is made to transmit information requesting the power transmission side to change the power supply frequency because the power supplied to the power receiving side is not sufficient, it does not reach the power transmitting side, and consequently power is supplied from the power transmitting side to the power receiving side. I can't do that.

  On the other hand, when power is supplied or communicated inside or outside the manhole by electromagnetic induction, it is possible to stably supply sufficient power for the operation of the electronic equipment in the manhole and to secure a sufficient reception level for demodulating the transmission signal. I need it. Therefore, it is required to control the power transmission side resonance coil and the power reception side resonance coil to face each other inside and outside the manhole, and to control the power transmission frequency and the resonance frequency to coincide with each other.

  However, the received power peak value varies as shown in FIG. 16 according to the distance between the power transmission resonance coil and the power reception resonance coil. Further, in the manhole installation environment, unlike the free space environment, the frequency characteristics of the received power value are different as shown in FIG. 17, and the peak frequency varies.

  If the manhole has a thick cast iron lid, and the magnetic field lines are absorbed by the lid, it is difficult to obtain sufficient power supply or signal power. A method for avoiding the influence of the manhole cover is considered. For example, as shown in FIG. 18, when the inclination of the power receiving resonance coil is set to 30 ° so as to avoid the manhole cover, the received power value is increased as compared with the case where the inclination of the manhole cover is an obstacle of 0 °. be able to. Further, by shifting and tilting the position of the power receiving resonance coil from the center line of the manhole, the influence of the manhole cover can be further avoided and the power receiving power value can be increased. However, since the position and inclination of the power reception side resonance coil have a range that can be adjusted according to the size of each manhole, the position and inclination of the power reception side resonance coil in the manhole may be different for each manhole.

  Therefore, it is necessary to adjust the position, inclination, and height of the power transmission side resonance coil and adjust the power supply frequency in accordance with the position and inclination of the power reception side resonance coil for each manhole. At that time, since the received power value notified from the power receiving side becomes one reference, the received power value is reliably transmitted from the power receiving side to the power transmitting side, and further, the position, inclination, height, It is necessary to adjust the power supply frequency.

  It is an object of the present invention to provide a resonance type wireless power transmission device capable of stably performing power feeding and communication by an electromagnetic induction method between a power transmission side device outside a manhole and a power reception side device inside a manhole. To do.

The present invention includes a power transmission side device disposed outside a manhole, a power reception side device disposed within a manhole, a power transmission side resonance coil electrically coupled to a power transmission side coil of the power transmission side device by electromagnetic induction, Using the resonance phenomenon between the power receiving side coil of the side device and the power receiving side resonance coil electrically coupled by electromagnetic induction, power is supplied from the power source connected to the power transmission side coil to the load connected to the power receiving side coil. In the resonance type wireless power transmission device for transmitting, the power receiving side device measures the power received by the load and outputs the received power value, and means for changing the load impedance of the load within a predetermined range by turning on and off the switch in association with the received power value and a control unit which controls the on-off switch, power-transmitting-side apparatus is generated in response to a change in load impedance corresponding to oFF of the switch transmission Detecting a transient response of the coil current, a demodulation unit that restores the received power value by the transient response, the control unit controls the on-off switch as the occurrence of the received power value and the transient response associated Then, the demodulation unit detects the current of the power transmission side coil by envelope detection, detects the transient response, and restores the received power value from the presence or absence of the transient response .

  In the resonant wireless power transmission device of the present invention, the power transmission side device is configured so that the power supply frequency of the power supply matches the resonance frequency of the power transmission side resonance coil and the power reception side resonance coil based on the received power value restored by the demodulation unit. Adjustment means for adjusting is provided.

  In the resonance type wireless power transmission device of the present invention, the power transmission side device adjusts the position and inclination of the power transmission side resonance coil based on the power reception power value restored by the demodulation unit, and the power transmission side resonance coil and the power reception side resonance coil Adjusting means for adjusting so as to face each other.

  In the resonance type wireless power transmission device of the present invention, the power transmission side device adjusts the height of the power transmission side resonance coil based on the received power value restored by the demodulation unit, and the power transmission side resonance coil, the power reception side resonance coil, Adjusting means for adjusting the distance between the two.

  The present invention adjusts the power supply frequency of the power transmission side device so as to match the resonance frequency according to the position and inclination of the power reception side resonance coil set so as to avoid the influence of the lid of the manhole. By adjusting the position, inclination, and height, power feeding and communication can be stably performed by an electromagnetic induction method between the power transmission side device outside the manhole and the power reception side device inside the manhole.

It is a figure which shows the 1st structural example of the resonance type wireless power transmission apparatus of this invention. It is a figure which shows the example 1 of transmission data and a received waveform. It is a figure which shows the example 2 of transmission data and a received waveform. It is a figure which shows the example 3 of transmission data and a received waveform. 3 is a diagram illustrating a configuration example of a demodulation unit 12. FIG. It is a figure which shows the relationship between the impedance seen from the power transmission side, and a power receiving level (electric current). It is a figure explaining the selection change procedure of the impedance seen from the power transmission side. It is a figure which shows the 2nd structural example of the resonance type wireless power transmission apparatus of this invention. It is a figure which shows the 3rd structural example of the resonance type wireless power transmission apparatus of this invention. It is a figure which shows the 4th structural example of the resonance type wireless power transmission apparatus of this invention. It is a figure explaining the impedance adjustment method of the impedance adjustment parts 31 and 32. FIG. It is a figure explaining the position adjustment procedure 1 of the power transmission side apparatus. It is a figure explaining the position adjustment procedure 2 of the power transmission side apparatus. It is a figure which shows the structural example of a resonance type wireless power transmission apparatus. It is a figure which shows the example of S parameter (S21) of a resonance coil. It is a figure which shows the distance between power transmission / reception coils, and received power peak value. It is a figure which shows the frequency characteristic of the received electric power value in a manhole installation environment. It is a figure which shows the inclination of a receiving side resonance coil, and S parameter (S21).

FIG. 1 shows a first configuration example of a resonance type wireless power transmission apparatus of the present invention.
In FIG. 1, the resonance type wireless power transmission device includes a power transmission side device 10 that is responsible for power transmission and a power reception side device 20 that receives the transmitted power, and transmits transmission data from the power reception side device 20 to the power transmission side device 10. Includes a configuration for transmitting. The flow of power and transmission data from the power transmission side device 10 to the power reception side device 20 is downward, and the flow of transmission data from the power reception side device 20 to the power transmission side device 10 is upward.

  The power transmission side device 10 includes a power source 11, a demodulation unit 12 that restores uplink transmission data sent from the power reception side device 20, a power transmission side coil 13, a power transmission side resonance coil 14, and a frequency adjustment unit 15 that adjusts the power frequency of the power source 11. Is provided. The power receiving side device 20 includes a power receiving side resonance coil 21, a power receiving side coil 22, a load 23, a resistor 24, a switch 25, a control unit 26, and a received power measuring unit 27. The power transmission side coil 13 and the power transmission side resonance coil 14 are electrically coupled by electromagnetic induction. The power transmission resonance coil 14 and the power reception resonance coil 21 are electrically coupled by resonance. The power receiving side resonance coil 21 and the power receiving side coil 22 are electrically coupled by electromagnetic induction. As a result, power is supplied from the power source 11 to the load 23, and the received power value is measured by the received power measuring unit 27 and notified to the control unit 26. As described below, the control unit 26 operates the switch 25 to perform processing for transmitting the received power value as transmission data. Similarly, the control unit 26 performs processing for transmitting sensor data in the wireless tag system as transmission data.

  Here, for the sake of simplicity, the impedance of the load 23 alone is not changed, and the impedance when the right side is viewed from B-B ′ in the figure is referred to as load impedance. The load impedance can take two states by selecting whether or not the resistor 24 is passed when the switch 25 is turned on / off. The control unit 26 is configured to turn on and off the switch 25 in accordance with transmission data and change the load impedance. However, in the configuration of the present embodiment, the power supply to the load 23 is continued because the connection to the load 23 is not released regardless of whether the switch 25 is on or off.

  In the configuration of FIG. 1, the resistor 24 and the switch 25 are connected in parallel, and the resistor 24 and the load 23 are connected in series. However, the resistor 24 and the switch 25 are connected in series, and the resistor 24 and the load 23 are connected. May be connected in parallel. Further, the circuit constant CR may be adjusted by a variable configuration of resistance and capacitance.

  Since the power receiving side device 20 and the power transmitting side device 10 are electrically coupled, the change in the load impedance is a change in impedance when the power receiving side device 20 is viewed from AA ′ of the power transmitting side device 10, and the current or voltage is changed. Appears as a change. The demodulator 12 detects this change and restores the transmission data transmitted from the power receiving side device 20.

  FIG. 2 shows a waveform obtained by envelope detection of the current or voltage in the demodulator 12 of the power transmission side device 10, and it can be seen that the current or voltage changes in conjunction with the change of transmission data. The demodulation unit 12 can restore the transmission data transmitted from the power receiving side device 20 by sampling this change at an appropriate timing.

  However, when the power supply frequency of the power transmission side device 10 is different from the resonance frequency, a reception waveform as shown in FIG. 3 is obtained. The average reception level (reception power) not only decreases compared to the case of FIG. 2, but also changes in the amplitude of the signal waveform are reduced. Furthermore, when the power supply frequency of the power transmission side device 10 is greatly different from the resonance frequency, the change in the amplitude of the signal waveform becomes very small, and it is difficult to restore the transmission data.

  On the other hand, the demodulator 12 of the power transmission side device 10 can observe a transient response of current or voltage corresponding to a change in transmission data as shown in FIG. Here, the transient response of the current or voltage observed in the power transmission side device 10 is a part where the switch 25 is turned on / off according to transmission data and the current or voltage rises and falls according to the change in the load impedance accompanying it. This is a phenomenon in which the waveform changes greatly. The control unit 26 of the power receiving side device 20 operates the switch 25 so that the transmission data corresponds to the occurrence of the transient response, and the demodulation unit 12 of the power transmission side device 10 restores the transmission data from the presence of the occurrence of the transient response. To do.

FIG. 5 shows a configuration example of the demodulation unit 12.
In FIG. 5, the demodulation unit 12 includes a detection unit 121, an A / D conversion unit 122, and a code determination unit 123. The detector 121 detects the received waveform, that is, the current or voltage in the power transmission side device 10. The detection output is digitized by the A / D converter 122, and the bit is determined by the code determination unit 123 and output.

  The code determination unit 123 has two code determination logics. The sign determination logic 1 outputs “1” when a positive transient response is determined from the received waveform, and outputs “0” when a negative transient response is determined, and determines a steady state (no transient response). If it does, the previous determination result is output. The code determination for the steady state may be configured such that the previous determination result is stored in a storage unit connected to the code determination unit 123 and read from the storage unit when the steady state is determined. The configuration may be such that the previous determination result is output until a positive or negative transient response is determined.

  The control unit 26 of the power receiving device 20 corresponding to the code determination unit 123 operates the switch 25 so as to correspond to the transmission data as it is. That is, if the transmission data is 1, the switch 25 is turned on, and if the transmission data is 0, the switch 25 is turned off. The sign determination unit 123 determines the bit at the timing when the transmission data is inverted and a transient response occurs, and outputs the same bit as the bit immediately before the transient response occurs at the timing when the transient response does not occur, thereby restoring the transmission data. To do.

  By detecting the presence or absence of such a transient response, transmission data (received power value) transmitted from the power receiving side device 20 by the power transmitting side device 10 even if the power frequency of the power transmitting side device 10 is slightly deviated from the resonance frequency. Can be restored.

  Therefore, when the power receiving side device 20 detects a shift in the power source frequency of the power transmitting side device 10 with respect to the resonance frequency due to a decrease in received power, the control unit 26 generates corresponding transmission data and switches the switch 25 to the above pattern. , The demodulator 12 of the power transmission side device 10 restores the transmission data, and can notify the deviation of the power supply frequency of the power transmission side device 10 with respect to the resonance frequency. However, since the power receiving side device 20 does not know the direction or amount of the power frequency shift of the power transmitting side device 10 with respect to the resonance frequency, the power receiving side device 20 transmits the received power value as transmission data. The demodulator 12 of the power transmission side device 10 reads the received power value from the control signal, and adjusts the power frequency of the power source 11 via the frequency adjuster 15 when it is less than the specified received power value. At this time, the power supply frequency can be adjusted so as to approach the resonance frequency by feedback control of the shift direction and shift amount of the power supply frequency from the change in the received power value with respect to the shift of the power supply frequency. As a result, the received power value in the power receiving device 20 can be increased.

  In addition, when the received power value is less than the specified value, (1) In addition to adjusting the power supply frequency to match the resonance frequency, (2) In order to make the power receiving side resonance coil 21 directly face the power transmission side resonance coil 14 Adjustment of the position and inclination of the power transmission side resonance coil 14, (3) Adjustment of the height of the power transmission side resonance coil 14 to optimize the distance between the resonance coils, and (4) Power transmission side in accordance with adjustment of the power supply frequency It is effective to combine adjustment of the circuit constant CR of the device. Note that if the position, inclination, or height of the power transmission resonance coil 14 is changed, the resonance frequency also changes, and accordingly, adjustment of the power supply frequency and adjustment of the circuit constant CR are also required. In FIG. 1, the circuit constant CR adjusting means in the power transmission side device 10 is omitted. While performing such adjustment, the received power value of the power receiving side device 20 is fed back to the power transmitting side device 10 and the adjustment is repeated, whereby the received power value can be set to satisfy the specified value.

  In addition, by mounting the power transmission side device 10 on a portable carriage, the position of the power transmission side resonance coil 14 can be easily adjusted around the manhole. Further, the tilt and height of the power transmission side resonance coil 14 can be adjusted by providing a mechanism for raising and lowering or tilting the power transmission side device 10 on the carriage.

  In the above embodiment, the method of transmitting a signal by a transient response when two impedance values (Za1, Za2) are changed in the power receiving side device 20 with respect to the transmission data “1”, “0” has been described. Here, if the power reception level (voltage / current) at each impedance value is further measured, it can be determined which impedance value has a higher power reception level. Therefore, by changing the impedance value used for the next modulation to a value with a higher power reception level and changing it to an impedance value that may further increase the impedance value, the impedance value that increases the power reception level while ensuring signal transmission is obtained. It becomes possible to select. This will be described in detail below.

FIG. 6 shows the relationship between the impedance and the power reception level (current) as seen from the power transmission side.
In FIG. 6, the horizontal axis represents the impedance Za as seen from the power transmission side device 10 to the power reception side device 20. Since the power receiving level (current) when the impedance of the power receiving side device 20 is changed using the transient response is already known, the power receiving level (currents Ia1, Za2) in the state of the impedance Za1, Za2 viewed from the power transmitting side corresponding to them is known. Ia2) is plotted on the graph of FIG. Next, the impedance Za3 to be selected next is determined based on the states of these two impedances Za1 and Za2.

  For example, Za3 linearly extended from Za1 in the direction of Za2 having a higher power reception level is determined in accordance with the amount of change in power reception level (increase from current Ia1 to Ia2) when changing from Za1 to Za2. There is a difference between the expected power reception level (current Ia3 ′) and the actually measured power reception level (current Ia3) when changing to this impedance Za3, but the power reception levels (currents Ia1 and Ia2) confirmed so far Higher than. By repeating this operation, the next impedance can be determined in sequence.

FIG. 7 shows an impedance selection change procedure as seen from the power transmission side.
In FIG. 7, since the current value at Za2 is larger than the impedance Za1 as described above, the impedance next to the impedance Za2 is changed in the order of Za3, Za4, Za5, Za6, Za7,. I will do it. Accordingly, assumed current values (assumed values) Ia3 ′, Ia4 ′, Ia5 ′, Ia6 ′, Ia7 ′,... And actually measured current values (measured values) Ia3, Ia4, Ia5, Ia6, Ia7, ... changes. Here, when the measured value falls below the measured value at the previous impedance, the impedance is developed in the reverse direction, and the moving distance is halved. For example, when the measured value Ia5 at Za5 falls below the measured value Ia4 at Za4, the next Za6 is a point obtained by extending a half distance from Za5 in the opposite direction of Za4. Further, this operation is repeated to search for an impedance value that can provide a higher measured value.

  In FIG. 7, the sign of the level difference is indicated by the direction of the thick arrow, and the magnitude of the level difference is indicated by its length. Hereinafter, the level difference is the absolute value of the difference between the assumed value and the measured value. Here, when the level difference in the impedance Za (X) is less than a predetermined value and is smaller than the level difference in the impedances Za (X-1) and Za (X + 1) before and after the impedance Za (X), the impedance Za (X) Is a definite value. For example, since the level difference in the impedance Za6 is equal to or smaller than a predetermined value and is smaller than the level difference in the impedances Za5 and Za7 before and after that, the impedance Za6 is set as a definite value. Therefore, if the level difference in the impedance Za4 becomes equal to or smaller than the predetermined value according to the predetermined value (threshold value), for example, the impedance Za4 becomes a definite value because it is smaller than the level difference in the impedances Za3 and Za5 before and after that.

  In the power transmission side device 10, as shown in FIGS. 6 and 7, it is necessary to achieve impedance matching while changing the impedance value viewed from the power transmission side. A configuration example provided with an impedance adjustment unit for this purpose is shown in FIGS.

  FIG. 8 shows a configuration in which an impedance adjustment unit 31 is connected between A-A ′ of the power transmission side device 10 and the power transmission side coil 13. The impedance adjusting unit 31 is a two-to-two terminal LC circuit having a variable inductance L and a variable capacitor C. When the switch is tilted to the left or right to change L or C, or the switch L is not tilted to the left or right. It is the structure which changes.

  9 shows a configuration in which the impedance adjustment unit 32 is connected to the power transmission side resonance coil 14, and FIG. 10 shows a configuration in which the impedance adjustment unit 32 is connected to the power reception side resonance coil 21. The impedance adjusting unit 32 is a one-to-two terminal LC circuit having a variable inductance L and a variable capacitor C, and one end of C is grounded.

  How to change the impedance using such impedance adjusting units 31 and 32 will be described with reference to the Smith chart shown in FIG.

  First, it is assumed that the initial impedance viewed from the power transmission side is at the position “1” in the Smith chart of FIG. In this Smith chart, the isoresistance circle is rotated from the position “1” to the position “2”. To move from “1” to “2”, the variable inductance L is adjusted (increased) by tilting the switch of the impedance adjusting unit 31 to the left in the configuration of FIG. Thereafter, alignment is performed by rotating on the equiconductance circle from the position “2” to “3”. For the movement from “2” to “3”, in the configuration of FIG. 8, the switch of the impedance adjustment unit 31 is tilted to the right to adjust (increase) the variable capacitor C to adjust the impedance.

  In the configuration of FIG. 9 and the configuration of FIG. 10, when the variable inductance L is adjusted without tilting the switch of the impedance adjustment unit 32 to the left and right, the shift is made from “1” to “2” on the Smith chart, and then the switch is moved. When the variable capacitor C is adjusted by tilting it to the left or right, the impedance is adjusted from “2” to “3” on the Smith chart.

The details of how to do this are explained in the following reference material.
(Reference Material 1) Satoshi Kitano, Hiroshi Takahashi, Hidemine Karaki, Shortwave Antenna Autotuner, Dengeki Technical Review No.24, 1990, pp.48-52
(Reference Material 2) Yuichi Ichikawa, Masaru Aoki, High-frequency circuit design in the GHz era, CQ Publishing Co., Ltd., 2003, Section 2.7 Technique for efficiently transmitting high-frequency signals "matching"

  Next, a method for adjusting the position of the power transmission side device 10 (power transmission side resonance coil 14) will be described. For example, after estimating the maximum impedance value as described above, the optimum position of the power transmission side device 10 is determined using the impedance value. This adjustment method is characterized in that the next point to be measured is determined based on the power reception level between a plurality of points.

  FIG. 12 shows the position adjustment procedure 1 of the power transmission side device. Here, a procedure for determining the next point to be measured by comparing the power reception level between the two points will be described.

  In FIG. 12, the power reception level (current) at each point on the XY plane is shown on the vertical axis. The points a, b, c, d, and e are represented by XY coordinates, and the numerical value indicates the power reception level at each point. First, the power reception levels corresponding to the two points a and b of the power transmission side device 10 are respectively measured by the power reception side device 20 and transmitted to the power transmission side device 10. Here, it is assumed that the power reception level at the point a is “4” and the power reception level at the point b is “6”. In this case, since the power reception level at the point b is higher than the point a, the power reception level at the point c is measured by moving from the point a to the point c extended by the same distance in the direction of the point b. Here, if the power reception level at the point c is higher than the point b, the power reception level is measured by moving from the point b to a point further extended by an equal distance in the direction of the point c. Here, since the power reception level at the point c is “5”, which is lower than the power reception level at the point b, the point b is determined as the optimum position.

  That is, the next point is set on the extension line having the higher power reception level at the two points, and the next point is set on the extension line when the power reception level is further increased. On the other hand, if the power reception level at the next point is lower than the power reception level at the immediately preceding point, the immediately preceding point is determined as the optimum position. Since this is limited to the points on the extension line of the first two points, the point is not on the extension line, for example, point d or point e shown in FIG. Even if there is a point with a high power reception level, it is not selected.

  FIG. 13 shows the position adjustment procedure 2 of the power transmission side device. Here, a procedure for determining a point to be measured next in a higher power reception level at a plurality of points to be developed will be described. The notation is the same as in FIG.

  In FIG. 13, it is assumed that the power reception level at point a is “4” and the power reception level at point b is “6”. At this time, a point having a higher power reception level is searched around the point b having a higher power reception level. First, a power reception level is measured in a concentric circle with a point ab as a center around a point b, for example, counterclockwise from the point c, and the process ends at a point higher than the power reception level “6” at the point b. Here, since the power reception level at the point c is “4”, the process proceeds to the next point d. Since the power reception level at this point d is “5”, the process moves to the next point e. Since the power reception level at this point e is “7”, which is higher than the point b, the processing ends.

  Next, the power reception level is measured in order from the point f in a concentric circle centered on the point e and having a radius of the point be, and then ends at a point higher than the power reception level “7” of the point e. Here, since the power reception level at the point f is “5”, the process proceeds to the next point g. Since the power reception level at this point g is “4”, the process moves to the next point h. Since the power reception level at this point h is “9”, which is higher than that at point e, the processing ends.

  If the search is first started clockwise from the point b, the point e with a higher power reception level is immediately found, and then the search is performed counterclockwise around the point e, the h with a higher power reception level is immediately found. To be found.

  Such a procedure is repeated, and when there is no point higher than the power reception level around the point x, the point x is determined as the optimum position.

  In other words, centering on the higher power reception level of two points, search for the power reception level of the surrounding points, move to a point with a higher power reception level, and repeat the same operation centering on that point to the next point Set. When there is no higher power reception level near a certain point, the point is determined as the optimum position. Here, the search order of the surrounding points is reversed every time the points move. As a result, it is possible to find a point with a higher power reception level and find the optimum point in the shortest time.

DESCRIPTION OF SYMBOLS 10 Power transmission side apparatus 11 Power supply 12 Demodulation part 121 Detection part 122 A / D conversion part 123 Code | symbol determination part 13 Power transmission side coil 14 Power transmission side resonance coil 15 Frequency adjustment part 20 Power reception side apparatus 21 Power reception side resonance coil 22 Power reception side coil 23 Load 24 resistance 25 switch 26 control unit 27 received power measurement unit 31, 32 impedance adjustment unit

Claims (4)

A power transmission side device is disposed outside the manhole, a power reception side device is disposed inside the manhole, a power transmission side resonance coil electrically coupled to a power transmission side coil of the power transmission side device by electromagnetic induction, and power reception by the power reception side device utilizing resonance phenomenon between the power receiving side resonance coil that is electrically coupled with the side coil and the electromagnetic induction, the transmitting power from the connected power source to the power transmission coil to a load connected to the power receiving coil In the resonance type wireless power transmission device,
The power receiving device is:
Means for measuring the power received by the load and outputting a received power value;
Means for changing the load impedance of the load in a predetermined range by turning on and off the switch;
A controller that controls on / off of the switch in association with the received power value , and
The power transmission side device is:
A demodulator that detects a transient response of the current of the power transmission side coil that occurs in response to a change in the load impedance corresponding to the on / off of the switch, and restores the received power value by the transient response ;
The control unit controls the on / off of the switch so that the received power value corresponds to the occurrence of the transient response,
The resonance type wireless power transmission device , wherein the demodulator detects an electric current of the coil on the power transmission side, detects the transient response, and restores the received power value from the presence or absence of the transient response. . In the resonance type wireless power transmission device according to claim 1,
The power transmission side device includes an adjusting unit configured to adjust a power supply frequency of the power source to match a resonance frequency of the power transmission side resonance coil and the power reception side resonance coil based on the received power value restored by the demodulation unit. A resonance type wireless power transmission apparatus comprising: In the resonance type wireless power transmission device according to claim 1,
The power transmission side device adjusts the position and inclination of the power transmission side resonance coil based on the received power value restored by the demodulator so that the power transmission side resonance coil and the power reception side resonance coil face each other. A resonance type wireless power transmission apparatus comprising an adjusting means for adjusting. In the resonance type wireless power transmission device according to claim 1,
The power transmission side device adjusts a height of the power transmission side resonance coil based on the received power value restored by the demodulation unit, and adjusts an interval between the power transmission side resonance coil and the power reception side resonance coil. A resonance type wireless power transmission apparatus comprising an adjusting means.

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