JP5883266B2 - Power transmission device and contactless power transmission system - Google Patents

Description

  The present invention relates to a power transmission device that transmits power to a power receiving device using magnetic resonance, and a contactless power transmission system including the power transmission device and the power receiving device.

  As this type of contactless power transmission system, the present applicant has already proposed a contactless power transmission system disclosed in Patent Document 1 below. This non-contact power transmission system includes a signal generation unit that generates an AC signal, a power transmission device that has a transmission antenna that receives an AC signal and generates an electromagnetic field, a reception antenna that generates an induced voltage using the electromagnetic field, and an induction A non-contact power transmission system including a power receiving device having a voltage generation unit that generates a voltage to be supplied to a load based on the voltage, wherein the power transmission device includes a variable capacitor between the signal generation unit and the transmission antenna. The first matching unit configured by the above is disposed, and the power receiving device includes a second matching unit configured by a variable capacitor between the receiving antenna and the voltage generating unit. In addition, a first processing unit that executes a first process for controlling the first matching unit to match the signal generation unit and the transmission antenna is provided, and a receiving antenna and a voltage generation unit are controlled by controlling the second matching unit. A second processing unit that executes a second process to be matched is provided.

  In this non-contact power transmission system, when the first processing unit detects the presence of the power receiving device, the capacitance value of the variable capacitor of the first matching unit is controlled to match the signal generating unit and the transmitting antenna. At the same time, the first processing unit controls the capacitance value of the variable capacitor of the second matching unit to shift the receiving antenna and the voltage generation unit to the matching state. Therefore, according to this power transmission system, even if the power receiving device is arranged at various distances with respect to the power transmitting device, not only the power transmitting device but also the power receiving device always has a short and long distance between the power transmitting device and the power receiving device. As a result, power transmission can be performed with good transmission efficiency. For this reason, according to this power transmission system, it is possible to expand the range of the distance between the power transmitting device and the power receiving device that can satisfactorily transmit power while minimizing a decrease in power transmission efficiency. .

  By the way, in the case of transmitting power of about several tens of watts (medium power) from the power transmitting device to the power receiving device in the above contactless power transmission system, as a variable capacitor used in a matching unit such as a power transmitting device, For example, a variable capacitor as disclosed in Patent Document 2 below is generally used. This variable capacitor includes a plurality of fixed wings and capacitive adjustment elements (rotary wings) arranged between each pair of fixed wings, and a shaft on which each wing is attached is rotated by a motor. Thus, the capacitance value can be changed by increasing / decreasing the area of each rotary blade overlying the fixed blade.

JP 2010-130800 A (page 5-9, FIG. 1) JP 2002-190414 A (page 4, FIG. 2)

  However, the following problems to be solved exist in the non-contact power transmission system in which the matching unit is configured by the variable capacitor described above. That is, in this non-contact type power transmission system, the power transmission device is configured to change the capacitance value of the variable capacitor by mechanically moving a component (a shaft on which each rotor blade is attached) by a motor. There is a problem to be solved that the time required to match the signal generation unit and the transmission antenna (the time required to shift to the matching state) becomes long. For this reason, for example, there is a problem to be solved that cannot be applied to a system that requires matching speed, such as a power transmission system in which a power transmission device and a power reception device move relatively within a range where power transmission is possible. doing. In addition, a variable capacitor that changes the capacitance value by moving the mechanical configuration as described above (the shaft to which each rotor blade is attached) and a motor that drives the variable capacitor have large outer shapes, and thus are provided. There is also a problem to be solved that the matching unit, by extension, the power transmission device, and further the contactless power transmission system having this power transmission device is increased in size.

  The present invention has been made to solve such a problem, and provides a power transmission device capable of shifting to a matching state in a short time while avoiding an increase in size, and a contactless power transmission system including the power transmission device. The main purpose.

In order to achieve the above object, a power transmission device according to claim 1 includes a signal generation unit that generates an alternating current signal, a transmission antenna that receives the supply of the alternating current signal to generate an electromagnetic field, and the signal generation unit and the transmission antenna. A power transmission device having a matching unit disposed therebetween and transmitting to a power receiving device having a receiving antenna that generates an induced voltage by the electromagnetic field and a voltage generation unit that generates a voltage to be supplied to a load based on the induced voltage The matching unit includes a variable capacitor circuit including a diode circuit including a variable capacitance diode that changes a capacitance value according to a reverse bias voltage applied to the cathode terminal with respect to the anode terminal. And changing the capacitance value of the variable capacitor circuit by controlling the reverse bias voltage, thereby transmitting the signal generator and the transmission A processing unit for executing a matching process for matching the antenna, is connected in parallel to the diode circuit, and a inductor to lower the lower limit of the capacity changing range for the electrostatic capacitance value.

Further, the power transmission device according to claim 2, wherein, in the power transmitting apparatus according to claim 1 Symbol placement, the diode circuit comprises a first sub-diode composed of one or more of the variable capacitance diodes connected in parallel in the forward direction from each other A circuit, and a second sub-diode circuit configured by one or a plurality of the variable capacitance diodes connected in parallel in the forward direction and connected in series facing the first sub-diode circuit, and the reverse A bias voltage is applied to each of the first sub-diode circuit and the second sub-diode circuit.

Further, the power transmission device according to claim 3, in the power transmitting apparatus according to claim 1 Symbol placement, the diode circuit is composed of a plurality of said variable capacitance diodes connected in parallel in the forward direction.

Further, the power transmission device according to claim 4, in the power transmitting apparatus according to claim 1 Symbol placement, the diode circuit includes a third sub-diode composed of one or more of the variable capacitance diodes connected in parallel in the forward direction from each other A circuit, and one or more variable capacitance diodes connected in parallel with each other in the forward direction, and the fourth sub-diode circuit connected in series with the third sub-diode circuit in the forward direction. A bias voltage is applied to each of the third sub-diode circuit and the fourth sub-diode circuit.

A power transmission device according to claim 5 is the power transmission device according to any one of claims 1 to 4 , wherein the power transmission device is disposed between the signal generation unit and the matching unit, so that a traveling wave power value and a reflected wave are disposed. A power measurement unit that measures a power value, wherein the signal generation unit is configured to control an output power value of the AC signal, and the processing unit matches the signal generation unit and the transmission antenna. In the state, the traveling wave power value, the reflected wave power value, the capacitance value of the variable capacitor circuit calculated from the reverse bias voltage, and the distance between transmission and reception between the power receiving device measured in advance and the While calculating the inter-transmission / reception distance based on the relationship with the output impedance of the matching unit, when determining that the calculated inter-transmission / reception distance is outside the range in which the signal generation unit and the transmission antenna can be matched, Stopping generation of the AC signal to the serial signal generator.

The power transmission device according to claim 6 is the power transmission device according to any one of claims 1 to 5 , wherein the matching unit includes a fixed capacitor and a parallel connection and a non-parallel connection of the fixed capacitor to the variable capacitor circuit. A capacitor addition circuit having a switching element for switching connection is provided.

A non-contact power transmission system according to a seventh aspect includes the power transmission device according to any one of the first to sixth aspects and the power reception device.

The power transmission device according to claim 1 and the contactless power transmission system according to claim 7 are configured by a variable capacitance diode that changes a capacitance value according to a reverse bias voltage applied to the cathode terminal with respect to the anode terminal. The matching section is configured by including a variable capacitor circuit having a diode circuit.

  Therefore, according to the power transmission device and the power transmission system, the capacitance value of the variable capacitor circuit of the matching unit can be instantaneously changed (changed) by changing the reverse bias voltage. The antenna can be matched in an extremely short time. As a result, even if the distance between the power transmission device and the power reception device (distance between transmission and reception) changes in real time, the matching state between the signal generation unit and the transmission antenna can be satisfactorily maintained. Transmission can be continued in an efficient state. In addition, since the variable capacitor circuit is configured using the variable capacitance diode, the power transmission device can be reduced in size.

Also, in this power transmission device and the contactless power transmission system, due to the provision of an inductor connected in parallel to the diode circuit, the lower limit of the capacity changing range for the capacitance value of the variable capacitor circuit is lowered It has been. Therefore, according to the power transmission device and the power transmission system, even when the distance between the power transmission device and the power reception device (distance between transmission and reception) is short, the signal generator and the transmission antenna are aligned to transmit power to the power reception device. Can be executed in an efficient state.

The power transmission device according to claim 2 and the non-contact power transmission system according to claim 7 include a first sub-diode circuit and a second sub-diode circuit connected in series facing the first sub-diode circuit. A reverse bias voltage is applied to each of the sub-diode circuits.

  Therefore, according to the power transmission device and the power transmission system, in the variable capacitor circuit, an AC signal is halved to the variable capacitance diode constituting the first sub-diode circuit and the variable capacitance diode constituting the second sub-diode circuit. It is possible to apply the pressure by dividing the pressure. For this reason, when the power of the AC signal is constant (the amplitude of the AC signal is constant), the reverse bias voltage can be maintained in the reverse bias state as compared with the configuration in which the variable capacitor diodes are not connected in series. The lower limit value can be lowered, and thereby the upper limit value of the capacitance change range for the capacitance value of the variable capacitor circuit can be increased. That is, the range of the distance between transmission and reception that can transmit power to the power receiving apparatus in the aligned state can be expanded.

According to contactless power transmission system of the power transmission apparatus and claim 7 according to claim 3, by configuring the diode circuit with a plurality of variable capacitance diodes connected in parallel in the forward direction from each other, each sub-diode circuit Compared to a configuration constituted by one variable capacitance diode, the upper limit value of the capacitance change range for each capacitance value of the variable capacitor circuit can be increased. That is, the range of the distance between transmission and reception that can transmit power to the power receiving apparatus in the aligned state can be expanded.

The power transmission device according to claim 4 and the contactless power transmission system according to claim 7 , wherein the diode circuit is one or a third sub-diode circuit composed of a plurality of variable capacitance diodes connected in parallel to each other in the forward direction. 1 or a plurality of variable capacitance diodes connected in parallel in the forward direction and having a third sub-diode circuit and a fourth sub-diode circuit connected in series in the forward direction. Applied to each of the sub-diode circuit and the fourth sub-diode circuit.

  Therefore, according to this power transmission device and this power transmission system, an AC signal is divided and applied to the variable capacitance diodes constituting the third sub-diode circuit and the variable capacitance diodes constituting the fourth sub-diode circuit. In addition, the capacitance changing range for the capacitance value of the entire variable capacitor circuit can be expanded.

According to the power transmission device according to claim 5 and the contactless power transmission system according to claim 7 , the distance between the power transmission device and the power reception device (inter-transmission / reception distance) deviates from a matching range, and the signal generator and the transmission Even if the antenna cannot be moved to the matching state, the generation of the AC signal from the signal generation unit is stopped, so that a large reflection that may occur when the generation of the AC signal is continued. Continuous application of an excessive voltage to each component of the first matching unit due to wave power can be reliably prevented.

According to the power transmission device according to claim 6 and the contactless power transmission system according to claim 7 , the matching unit includes a fixed capacitor and a switching element that switches between parallel connection and non-parallel connection of the fixed capacitor to the variable capacitor circuit. Since the capacitance adding circuit having the variable capacitor circuit and the capacitance adding circuit as a whole can be changed within the variable capacitance range of the variable capacitor circuit alone, the capacitance of the variable capacitor circuit alone can be changed. The electrostatic capacitance value obtained by adding the capacitance value of the fixed capacitor to the lower limit value of the variable range as the lower limit value, and adding the capacitance value of the fixed capacitor to the upper limit value of the capacitance variable range of the variable capacitor circuit alone Since it can be changed within another capacitance variable range with the capacitance value as the upper limit value, it can be compared with a configuration with only a variable capacitor circuit. Variable range can be expanded. Therefore, according to the power transmission device and the non-contact power transmission system, a range in which power can be efficiently transmitted to the power receiving device while maintaining a good matching state between the signal generation unit and the transmission antenna (power transmission) The distance between the device and the power receiving device can be increased.

1 is a block diagram of a power transmission system 1. FIG. 4 is a flowchart for explaining an operation of a power transmission process 50 in the power transmission system 1. 3 is a circuit diagram of a first matching unit 13 and a transmission antenna 12 in the power transmission device 2. FIG. 3 is a circuit diagram of a second matching unit 22 and a receiving antenna 21 in the power receiving device 3. FIG. 4 is a circuit diagram for explaining a specific configuration of a first matching unit 13; FIG. It is explanatory drawing for demonstrating the relationship between the output impedance Zout of the 1st matching part 13, and the distance between transmission / reception. It is explanatory drawing for demonstrating the relationship between the electrostatic capacitance value Ctp of each variable capacitor circuit 13a, 13b, and the distance between transmission / reception. It is explanatory drawing for demonstrating the relationship between the electrostatic capacitance value Ctp of each variable capacitor circuit 13a, 13b, and the control voltage Vs. It is a circuit diagram for demonstrating another specific structure of the variable capacitor circuit 13a. It is a circuit diagram for demonstrating another specific structure of the variable capacitor circuit 13a. It is a circuit diagram for demonstrating another specific structure of the variable capacitor circuit 13a. It is a circuit diagram for demonstrating the concrete structure of the capacity | capacitance addition circuit 13c. FIG. 10 is a circuit diagram for explaining another specific configuration of the capacitance adding circuit 13c. FIG. 10 is a circuit diagram for explaining another specific configuration of the capacitance adding circuit 13c. FIG. 10 is a circuit diagram for explaining another specific configuration of the capacitance adding circuit 13c. It is a circuit diagram for demonstrating the structure which connected the several capacitance addition circuit 13c.

  Hereinafter, embodiments of a power transmission device and a contactless power transmission system will be described with reference to the accompanying drawings.

  A contactless power transmission system (hereinafter also simply referred to as “power transmission system”) 1 illustrated in FIG. 1 includes a power transmission device 2 and a power reception device 3 as an example, and the power transmission device 2 is connected to the power reception device 3. The power is transmitted in a non-contact manner, and the power received by the power receiving device 3 from the power transmitting device 2 is output to the load (in this example, a battery as an example) 4.

  The power transmission device 2 includes a signal generation unit 11, a transmission antenna 12, a first matching unit 13, a power measurement unit 14, and a first processing unit 15. The signal generator 11 generates and outputs an AC signal S1 (in this example, as an example, an AC signal having a frequency f (several MHz to several tens of MHz; as an example, 13.56 MHz). Controlled by the first processing unit 15, the output power value of the AC signal S1 can be changed.

  As an example, the transmission antenna 12 is formed in a coil shape (a helical spring shape or a planar coil shape). In addition, the transmission antenna 12 is supplied with the AC signal S <b> 1, generates an electromagnetic field, and is electromagnetically coupled to a later-described reception antenna 21 provided in the power receiving device 3.

  The first matching unit (matching unit) 13 is disposed between the signal generation unit 11 and the transmission antenna 12 (specifically, installed in a transmission path connecting the signal generation unit 11 and the transmission antenna 12). The impedance on the signal generating unit 11 side is matched with the impedance (input impedance) of the transmitting antenna 12 that changes according to the distance between the receiving antenna 21 and the signal generating unit 11 and the transmitting antenna 12 are matched. ).

  In this example, as an example, as shown in FIG. 3, the first matching unit 13 includes a variable capacitor circuit 13 a connected in parallel to the transmission antenna 12 and a series (specifically, the transmission antenna 12). And a variable capacitor circuit 13b connected in series to a parallel circuit including the transmission antenna 12 and the variable capacitor circuit 13a. Further, the first matching unit 13 is configured so that the capacitance values of the variable capacitor circuits 13a and 13b are independently determined by the control voltages Vsa1 and Vsb1 (DC voltages that are reverse bias voltages) output from the first processing unit 15. By being controlled, the transmitting antenna 12 (specifically, the input impedance of the transmitting antenna 12 viewed from the signal generating unit 11 side) and the signal generating unit 11 (specifically, the signal generating unit 11 side viewed from the transmitting antenna 12 side). Output impedance).

  Specifically, as shown in FIG. 5, the variable capacitor circuit 13a includes a diode circuit DCa, two capacitors 35a and 36a that are small electronic components, one inductor 37a that is a small electronic component, and 3 that is a small electronic component. Two inductors 38a, 39a, and 40a and three resistors 41a, 42a, and 43a, which are small electronic components, are provided. In this case, the diode circuit DCa is composed of a first sub-diode circuit DCa1 composed of a diode 31a as a variable capacitance diode which is a small electronic component, and a second diode 32a composed of a variable capacitance diode which is a small electronic component. A sub-diode circuit DCa2 is provided. The first sub-diode circuit DCa1 is configured by one diode 31a or a plurality of diodes 31a connected in parallel in the forward direction (the cathode terminals are connected to each other and the anode terminals are connected to each other). The second sub-diode circuit DCa2 includes one diode 32a or a plurality of diodes 32a connected in parallel to each other in the forward direction. Further, the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2 thus configured are connected in series facing each other (the cathode terminals are connected to each other or the anode terminals are connected to each other. In this example, The cathode terminals are connected). As the diode 31a and the diode 32a, and the diode 31b and the diode 32b described later, a Schottky barrier diode or a fast recovery diode is used.

  One end of the capacitor 35a is connected to one end of the diode circuit DCa (the anode terminal of each diode 31a), and the other end is connected to the variable capacitor circuit 13b and the transmission antenna 12 as one end of the variable capacitor circuit 13a. The capacitor 36a has one end connected to the other end of the diode circuit DCa (the anode terminal of each diode 32a) and the other end as the other end of the variable capacitor circuit 13a. Ground potential). With this configuration, the two capacitors 35a and 36a are respectively connected in series to the diode circuit DCa.

  The capacitors 35a and 36a are DC cut capacitors for preventing the control voltage Vsa1 applied to the diode circuit DCa of the variable capacitor circuit 13a from leaking to the outside of the variable capacitor circuit 13a, and the AC signal S1. Is defined as a capacitance value that is sufficiently smaller than the impedance of the diode circuit DCa (for example, a capacitance value that is twice or more the combined capacitance value of the diode circuit DCa). Have been).

  The inductor 37a has one end connected to the other end of the capacitor 35a and the other end connected to the other end of the capacitor 36a. With this configuration, the inductor 37a is connected as a parallel inductor in parallel with the diode circuit DCa, specifically, in parallel with the series circuit of the capacitors 35a and 36a and the diode circuit DCa. As will be described later, the inductor 37a has a function of lowering the lower limit value of the capacitance change range for the capacitance value Ctp1 of the variable capacitor circuit 13a that is changed by the control voltage Vsa1.

  The inductor 38a and the resistor 41a are connected in series with each other and are disposed between one end of the diode circuit DCa and the reference potential. The inductor 39a and the resistor 42a are connected in series with each other and are disposed between the other end of the diode circuit DCa and the reference potential. The inductor 40a and the resistor 43a are connected in series with each other, and one end of these series circuits (in this example, the end on the inductor 40a side) is the first sub-diode circuit DCa1 and the second sub-diode in the diode circuit DCa. The connection point CNa of the circuit DCa2 (in this example, the cathode terminal of each of the diodes 31a and 32a) is connected. The series circuit of the inductor 40a and the resistor 43a supplies the control voltage Vsa1 output from the processing unit 15 to the connection point CNa of the diode circuit DCa.

  The inductors 38a, 39a, and 40a have an inductance value defined so that the impedance at the frequency f of the AC signal S1 is sufficiently high, and are supplied with the reference potential of the AC signal S1 and the control voltage Vsa1. Has a function of reducing leakage of the alternating current signal S1. The resistors 41a, 42a, 43a are connected to the inductors 38a, 39a, 40a, the currents flowing through the diodes 31a, 32a, and the direct currents flowing through the supply lines to which the control voltage Vsa1 is supplied in the supply state of the control voltage Vsa1. It has a function to limit current.

  In the variable capacitor circuit 13a configured as described above, the control voltage Vsa1 as a DC voltage is applied to each of the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2 via the series circuit of the inductor 40a and the resistor 43a. , And supplied (applied) with a reverse bias polarity. The diodes 31a and 31b have a characteristic of changing the inter-terminal capacitance value according to the reverse bias voltage. Therefore, since the capacitance value of the diode circuit DCa (the combined capacitance value of the sub-diode circuits DCa1 and DCa2) changes according to the voltage value of the control voltage Vsa1, the capacitance value Ctp1 of the variable capacitor circuit 13a is also controlled by the control voltage Vsa1. It changes according to the voltage value.

  As shown in FIG. 5, the other variable capacitor circuit 13b also includes a diode circuit DCa, two capacitors 35a, 36a, one inductor 37a, three inductors 38a, 39a, 40a, and three A variable capacitor circuit including a diode circuit DCb, two capacitors 35b and 36b, one inductor 37b, three inductors 38b, 39b and 40b, and three resistors 41b, 42b and 43b respectively corresponding to the resistors 41a, 42a and 43a The configuration is the same as 13a. Therefore, the description of the function of each component of the variable capacitor circuit 13b, which is the same as the corresponding component of the variable capacitor circuit 13a, is omitted.

  In this case, the diode circuit DCb includes a first sub-diode circuit DCb1 constituted by a diode 31b as a variable capacitance diode, and a second sub-diode circuit DCb2 constituted by a diode 32b as a variable capacitance diode. The first sub-diode circuit DCb1 includes a single diode 31b or a plurality of diodes 31b connected in parallel to each other in the forward direction. The second sub-diode circuit DCb2 includes one diode 32b or a plurality of diodes 32b connected in parallel to each other in the forward direction. The first sub-diode circuit DCb1 and the second sub-diode circuit DCb2 are connected in series so as to face each other.

  One end of the capacitor 35b is connected to one end of the diode circuit DCb (the anode terminal of each diode 31b), and the other end is connected to the power measuring unit 14 as one end of the variable capacitor circuit 13b. One end of the capacitor 36b is connected to the other end of the diode circuit DCb (the anode terminal of each diode 32b), and the other end is connected to one end of the variable capacitor circuit 13a as the other end of the variable capacitor circuit 13b. With this configuration, the two capacitors 35b and 36b are respectively connected in series to the diode circuit DCb.

  The inductor 37b has one end connected to the other end of the capacitor 35b and the other end connected to the other end of the capacitor 36b. With this configuration, the inductor 37b is connected as a parallel inductor in parallel with the diode circuit DCb, specifically, in parallel with the series circuit of the capacitors 35b and 36b and the diode circuit DCb.

  The inductor 38b and the resistor 41b are connected in series with each other and are disposed between one end of the diode circuit DCb and the reference potential. The inductor 39b and the resistor 42b are connected in series with each other and are disposed between the other end of the diode circuit DCb and the reference potential. The inductor 40b and the resistor 43b are connected to each other in series, and one end of these series circuits (in this example, the end on the inductor 40b side) is the first sub-diode circuit DCb1 and the second sub-diode in the diode circuit DCb. The connection point CNb of the circuit DCb2 (in this example, the cathode terminal of each of the diodes 31b and 32b) is connected. The series circuit of the inductor 40b and the resistor 43b supplies the control voltage Vsb1 output from the processing unit 15 to the connection point CNb of the diode circuit DCb.

  In the variable capacitor circuit 13b configured as described above, the control voltage Vsb1 as a DC voltage is applied to each of the first sub-diode circuit DCb1 and the second sub-diode circuit DCb2 via the series circuit of the inductor 40b and the resistor 43b. , And supplied (applied) with a reverse bias polarity. Accordingly, since the capacitance value of the diode circuit DCb (the combined capacitance value of the sub-diode circuits DCb1 and DCb2) changes according to the voltage value of the control voltage Vsb1, the electrostatic capacitance value Cts1 of the variable capacitor circuit 13b is also controlled by the control voltage Vsb1. It changes according to the voltage value.

  As shown in FIG. 1, the power measuring unit 14 is disposed between the signal generating unit 11 and the first matching unit 13 (specifically, the signal generating unit 11 and the first matching unit 13 are connected to each other). Generated in the transmission line), the traveling wave power value (traveling wave power value) W2a for the AC signal S1 from the signal generating unit 11 to the first matching unit 13 side, and the first matching unit 13 generates a signal. The power value (reflected wave power value) W2b of the reflected wave for the AC signal S1 returning to the unit 11 side is measured and output to the first processing unit 15 as power information.

  As an example, the first processing unit 15 includes a CPU and an internal memory (both not shown), and controls the signal generating unit 11 and controls the first matching unit 13 to control the signal generating unit 11 ( Specifically, a power transmission process 50 (see FIG. 2) including a matching process for shifting the power measurement unit 14 and the signal generation unit 11) and the transmission antenna 12 to a matching state is executed.

  The power receiving device 3 includes a receiving antenna 21, a second matching unit 22, a rectifying unit 23, and a second processing unit 24. The receiving antenna 21 is formed in the same coil shape as the transmitting antenna 12 as an example, and is defined by the same inductance as the transmitting antenna 12. The reception antenna 21 is electromagnetically coupled to the transmission antenna 12 of the power transmission device 2 (that is, due to an electromagnetic field generated by the transmission antenna 12), and generates an induced voltage V1 between both ends thereof. The second matching unit 22 is disposed between the receiving antenna 21 and the rectifying unit 23 (specifically, interposed in a transmission path connecting the receiving antenna 21 and the rectifying unit 23), and the receiving antenna. The impedance of 21 (output impedance) and the impedance of the rectifying unit 23 are matched (the receiving antenna 21 and the rectifying unit 23 are shifted to the matching state).

  In this example, as an example, as shown in FIG. 4, the second matching unit 22 includes a variable capacitor circuit 22 a connected in parallel to the reception antenna 21 and a series connection to the reception antenna 21 (that is, the reception antenna). 21 and a variable capacitor circuit 22b connected in series to a parallel circuit composed of the variable capacitor circuit 22a. In this example, as an example, although not shown, the variable capacitor circuit 22a is configured the same as the variable capacitor circuit 13a of the first matching unit 13, and the variable capacitor circuit 22b includes the variable capacitor circuit 13b of the first matching unit 13. It is configured identically. Further, in the second matching unit 22, the electrostatic capacitance values Ctp2 and Cts2 of the variable capacitor circuits 22a and 22b are separately determined by the control voltages Vsa2 and Vsb2 (DC voltages that are reverse bias voltages) output from the second processing unit 24. By being controlled independently, the receiving antenna 21 (specifically, the output impedance of the receiving antenna 21 viewed from the rectifying unit 23 side) and the rectifying unit 23 (specifically, the input of the rectifying unit 23 viewed from the receiving antenna 21 side). Impedance).

  When it is not particularly necessary to distinguish the capacitance values Ctp1 and Cts1 of the variable capacitor circuits 13a and 13b from the capacitance values Ctp2 and Cts2 of the variable capacitor circuits 22a and 22b, the antenna (the transmission antenna 12 or the reception antenna 21). The capacitance value of the variable capacitor circuit (variable capacitor circuits 13a and 22a) connected in series with C) is denoted as Ctp, and the capacitance value of the variable capacitor circuit (variable capacitor circuits 13b and 22b) connected in parallel. Is expressed as Cts. Further, the control voltages Vsa1, Vsb1 and the control voltages Vsa2, Vsb2 are also expressed as the control voltage Vs unless otherwise distinguished.

  The rectifier 23 is an example of a voltage generator, and receives the induced voltage V1 generated in the receiving antenna 21 via the second matching unit 22 and supplies a voltage (to the battery 4 based on the induced voltage V1) ( In this example, a DC voltage (Vo) is generated. Specifically, the rectifying unit 23 includes a rectifying circuit and a smoothing circuit, rectifies and smoothes the induced voltage (AC voltage) V1 output from the second matching unit 22, and generates the voltage Vo. The voltage Vo thus output is output to the battery 4. In this example, as an example, each component in the power receiving device 3 operates by being supplied with this voltage Vo from the rectifying unit 23. Note that a battery (not shown) that charges the voltage Vo supplied from the rectifier 23 may be provided, and each component in the power receiving device 3 may be operated by the voltage of the battery. Moreover, it can replace with the rectifier 23 and can comprise a voltage generation part with a DC-DC converter, an AC-DC converter, or an AC-AC converter, for example.

  The second processing unit 24 includes, for example, a CPU and an internal memory (both not shown), and controls the second matching unit 22 to receive the antenna 21 and the battery 4 (specifically, the rectifying unit 23). And the battery 4) are moved to the above-described matching state.

  Next, the operation of the power transmission system 1 will be described. As an example, it is assumed that the frequency f of the AC signal S1 is defined as 13.56 MHz. Each inductor 38a, 39a, 40a, 38b, 39b, 40b has an inductance value defined as 100 μH as an example so that the impedance at this frequency f is sufficiently high (impedance is about 8. 5 kΩ).

  Further, in the power receiving device 3, immediately after shifting to the operating state, the second processing unit 24 controls the variable capacitor circuits 22 a and 22 b of the second matching unit 22 to have a control voltage Vsa2 having a predetermined DC voltage value. , Vsb2 to set the capacitance value of each variable capacitor circuit 22a, 22b to a specified capacitance value, and the receiving antenna 21 and the rectifying unit 23 are shifted to a good matching state and maintained. And

  In addition, the power transmission device 2 and the power reception device 3 that has shifted to the matching state as described above are relatively within a range of 0.1 m to 0.4 m (hereinafter, also referred to as “movement range”) as an example. It is assumed that the power transmission device 2 transmits power to the power reception device 3 in a moving state (a state in which the distance between transmission and reception changes within a range of 0.1 m to 0.4 m). Further, in a state where the distance between transmission and reception is changed within the range of 0.1 m to 0.4 m, the output impedance Zout of the first matching unit 13 in the power transmission device 2 (see the transmission antenna 12 side from the output of the first matching unit 13). The resistance R and the reactance X of the impedance after the transmitting antenna 12 change as shown in FIG. 6 as an example. In this case, the first matching unit 13 having the configuration shown in FIGS. 3 and 5 with respect to the impedance Zout that changes as shown in FIG. 6 when the distance between transmission and reception changes within the range of 0.1 m to 0.4 m. As shown in FIG. 7, the capacitance value Ctp of the variable capacitor circuit 13a in the first matching unit 13 is set to 20 pF according to the distance between transmission and reception. It is necessary to change the capacitance value Cts of the variable capacitor circuit 13b within a range of 20 pF to 150 pF.

  For this reason, as an example, in the variable capacitor circuit 13a, the first sub-diode circuit DCa1 configured by connecting the four diodes 31a in parallel and the second sub-diode circuit DCa2 configured by connecting the four diodes 32a in parallel. Is used to configure the diode circuit DCa, and in the variable capacitor circuit 13b, the first sub-diode circuit DCb1 configured by connecting the four diodes 31b in parallel and the four diodes 32b are connected in parallel. By configuring the diode circuit DCb using the sub-diode circuit DCb2, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b can be changed in the above-described range. In addition, the capacitance values of the capacitors 35a, 36a, 35b, and 36b are sufficiently larger than the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b (in this example, 4000 pF as an example). ).

  Further, when the control voltage Vs is changed from 1 V to 200 V, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b are as shown by the broken lines in FIG. 8 in the configuration without the inductor 37a and the inductor 37b. Although it changes within the range of 639.5 pF to 95.2 pF, the lower limit value (95.2 pF) does not reach the required lower limit value 20 pF of the aforementioned capacitance value Cts. On the other hand, in the configuration including the inductor 37a and the inductor 37b, by setting the inductance of the inductors 37a and 37b to 1.617 μH, the static voltage when the control voltage Vs is changed from 1V to 200V as shown by the solid line in FIG. It becomes possible to change the lower limit values of the capacitance values Ctp and Cts to 20 pF or less (10 pF in this example).

  A procedure for calculating the inductances of the inductors 37a and 37b will be described. In this example, as shown in FIG. 7, the lower limit value of the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b when the distance between transmission and reception is 0.1 m or more and 0.4 m or less is 20 pF. However, in order to give a margin to the lower limit value of the variable range of the capacitance values Ctp and Cts, an inductance that can change the lower limit value of the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b to 10 pF is calculated. It shall be.

First, the lower limit value of the capacitance values Ctp and Cts in the absence of the inductors 37a and 37b is 95.2 pF as described above (see FIG. 8), and the capacitance value reduction range for reducing this to 10 pF. Csub is 85.2 (= 95.2-10) pF. In addition, the reactance Xsub corresponding to the reduction width Csub is 137.76 (= 1 / (2 × π × 13.56 × 10 ⁶ × 85.2 × 10 ⁻¹² ) Ω. The inductance of 37a is calculated as 1.617 (= Xsub / (2 × π × 13.56 × 10 ⁶ )) μH described above.

  In addition, for the variable capacitor circuits 22a and 22b configured in the same manner as the variable capacitor circuits 13a and 13b, the inductance values of inductors (not shown) connected in parallel to these are the same as the inductances 37a and 37b described above. It is prescribed.

  In addition, the variable capacitor circuit 13a of this example includes a diode circuit DCa configured by connecting the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2 in series with each other facing each other, and the variable capacitor circuit 13b includes: The first sub-diode circuit DCb1 and the second sub-diode circuit DCb2 have a diode circuit DCb configured in series in a state of being opposed to each other. For this reason, the input AC signal S1 is applied to each of the diodes 31a, 32a, 31b, and 32b in a state of being divided into ½. Further, in order for each of the diodes 31a, 32a, 31b, and 32b to function as a variable capacitance diode, the control voltages Vsa1 and Vsb1 higher than the divided and applied AC signal S1 are applied. It must be maintained in a biased state.

  Moreover, the 1st process part 15 and the 2nd process part 24 change the control voltage Vs within the range of 31V to 200V of the variable range of the control voltage Vs shown in FIG. 8 as an example. Thereby, as shown in FIG. 8, the 1st process part 15 and the 2nd process part 24 change the electrostatic capacitance values Ctp and Cts about variable capacitor circuit 13a, 13b in the range of 10 pF or more and 150 pF or less. Further, even if the power of the AC signal S1 output from the signal generator 11 is increased to about 50 W, the lower limit voltage value of the control voltage Vs is 31 V. Therefore, each diode 31a, 32a, 31b, It has been confirmed by simulation that 32b is always maintained in the reverse bias state.

  In the power transmission system 1 configured as described above, as described above, first, the power receiving device 3 shifts to a matching state in which the receiving antenna 21 and the rectifying unit 23 are matched. Next, in the power transmission device 2, the first processing unit 15 executes the power transmission process 50 illustrated in FIG. In the power transmission process 50, the first processing unit 15 first starts outputting the control voltages Vsa1 and Vsb1 at a predetermined initial voltage, and each variable capacitor circuit 13a, 13b is initially set to predetermined capacitance values Ctp and Cts (step 51). Specifically, when the distance (inter-transmission / reception distance) of the power receiving device 3 to the power transmitting device 2 is a specific distance within a range of 0.1 m to 0.4 m, the power transmitting device 2 is connected to the power receiving device 3. The capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b are set to the capacitance values necessary for matching. For example, as shown in FIG. 7, the capacitance value Ctp (= 90 pF) and the capacitance value Cts (= 80 pF) when the specific distance is 0.2 m are set.

  Next, the first processing unit 15 starts power transmission (power transmission) with low power (step 52). Specifically, the 1st process part 15 performs the control process with respect to the signal generation part 11, and outputs alternating current signal S1 with small electric power (for example, 1 W or less). As a result, the AC signal S1 output from the signal generation unit 11 is supplied to the transmission antenna 12 via the power measurement unit 14 and the first matching unit 13, and transmission with low power is started. The power measuring unit 14 starts measuring the traveling wave power value W2a and the reflected wave power value W2b for the AC signal S1, and outputting the measured power values W2a and W2b to the first processing unit 15.

  Subsequently, the first processing unit 15 starts the first matching process (step 53). In the first matching process, the first processing unit 15 obtains the reflected wave power value W2b output from the power measuring unit 14, while the reflected wave power value W2b is defined in advance as a predetermined threshold (low power transmission). Threshold value (hereinafter also referred to as “first threshold value”). By changing (continuously changing) the control voltages Vsa1 and Vsb1 to the first matching unit 13, each variable capacitor circuit 13a, The capacitance values Ctp and Cts of 13b are continuously changed. In this power transmission system 1, each of the variable capacitor circuits 13a and 13b of the first matching unit 13 is composed of diodes 31a, 32a, 31a, and 32a, and instantly according to changes in the control voltages Vsa1 and Vsb1. It is possible to change (change) the electrostatic capacitance values Ctp and Cts. Therefore, the first processing unit 15 shifts the first matching unit 13 in a very short time to a state where the reflected wave power value W2b is equal to or lower than the first threshold, that is, a state where the power transmission device 2 and the power reception device 3 are matched. Let

  In addition, with the change of the distance (distance between transmission and reception) between the power transmission device 2 and the power reception device 3, the matching state between the power transmission device 2 and the power reception device 3 also changes, and the reflected wave power output from the power measurement unit 14 The value W2b also changes. For this reason, the first processing unit 15 repeatedly executes the first matching process described above to continuously change (change) the control voltages Vsa1 and Vsb1 to the first matching unit 13 in real time. The electrostatic capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b are continuously changed in real time to maintain the reflected wave power value W2b so as to be equal to or lower than the first threshold value.

  Next, the first processing unit 15 starts transmission (power transmission) of medium power (step 54). Specifically, the 1st processing part 15 performs control with respect to the signal generation part 11, and makes alternating current signal S1 medium electric power (for example, electric power exceeding 1W and several dozen W. In this example, it is 50W as an example). To output. As a result, the AC signal S1 output from the signal generator 11 is supplied to the transmission antenna 12, and power transmission with medium power is started.

  Subsequently, the first processing unit 15 executes a second matching process (step 55). In the second matching process, the first processing unit 15 obtains the reflected wave power value W2b output from the power measuring unit 14, and the reflected wave power value W2b is set to a predetermined threshold value (medium power transmission). Threshold value (hereinafter also referred to as “second threshold value”) The control voltages Vsa1 and Vsb1 to the first matching unit 13 are changed so as to be equal to or lower (that is, the capacitance values Ctp of the variable capacitor circuits 13a and 13b). , Cts). Also in this case, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b are instantaneously changed by changing (changing) the control voltages Vsa1 and Vsb1 in the same manner as in the first matching process. Since the first processing unit 15 can change (change) the first processing unit 15 in a state where the reflected wave power value W2b is equal to or lower than the second threshold, that is, in a state where the power transmission device 2 and the power reception device 3 are matched. The matching unit 13 is moved in a very short time.

  Thereafter, the first processing unit 15 repeatedly executes the second matching process described above, and continuously changes (changes) the control voltages Vsa1 and Vsb1 to the first matching unit 13 in real time. The electrostatic capacitance values Ctp and Cts of the capacitor circuits 13a and 13b are continuously changed in real time to maintain the reflected wave power value W2b so as to be equal to or lower than the second threshold value. Thereby, even if the distance (distance between transmission and reception) between the power transmission device 2 and the power reception device 3 changes within the range of 0.1 m to 0.4 m, the medium power is transmitted from the power transmission device 2 to the power reception device 3. The power transmission at is continuously executed efficiently.

  In addition, the first processing unit 15 executes a reception state determination process together with the above-described second matching process (step 56). In this reception state determination process, the first processing unit 15 first proceeds with the traveling wave power value W2a acquired from the power measurement unit 14 in a state where the reflected wave power value W2b is maintained below the second threshold (matching state). Is divided by the reflected wave power value W2b to calculate the ratio (W2a / W2b) of the traveling wave power value W2a to the reflected wave power value W2b, and the input impedance of the first matching unit 13 is calculated based on this ratio. . The first processing unit 15 calculates the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b based on the current control voltages Vsa1 and Vsb1 supplied to the first matching unit 13. In addition, the internal impedance of the first matching unit 13 is calculated based on the calculated capacitance values Ctp and Cts. Next, the first processing unit 15 calculates the impedance Zout (resistance R and reactance X) after the transmission antenna 12 in the power transmission device 2 based on the above-described input impedance and internal impedance of the first matching unit 13.

  Subsequently, the first processing unit 15 determines the distance (transmission / reception) between the power transmission device 2 and the power reception device 3 from the calculated impedance Zout (resistance R and reactance X) and the relationship between the impedance Zout and the distance between transmission and reception illustrated in FIG. (Distance between transmission and reception) is calculated in real time, and whether or not the distance between transmission and reception is included in the range of 0.1 m to 0.4 m based on the calculated distance (that is, the distance between transmission and reception is 0.1 m to 0). .. whether or not out of the range of 4 m). As a result of the determination, the first processing unit 15 determines that the reception state is good when the calculated distance is included in the range of 0.1 m to 0.4 m, and determines that the reception state is out when it is determined that it is out of the range. Is determined to be defective. The first processing unit 15 executes a reception state determination process every time the control voltages Vsa1 and Vsb1 are changed, and determines the reception state.

  Further, the first processing unit 15 determines whether or not a predetermined stop condition for power transmission at medium power is satisfied while executing the second matching process and the reception state determination process (step 57). In this example, as an example, when the first processing unit 15 determines that the reception state is bad in the reception state determination processing, and the first processing unit 15 receives a forced stop signal for the power transmission processing from the outside. It is determined that the stop condition is satisfied at any time. When the first processing unit 15 determines in step 57 that the stop condition is not satisfied, the first processing unit 15 continues to execute the second matching process and the reception state determination process. When it is determined that the stop condition is satisfied, the first processing unit 15 The control process for the generator 11 is executed to stop the output of the AC signal S1, thereby stopping the transmission (power transmission) of the medium power (step 58). Thereby, the power transmission process 50 ends.

  When the distance between transmission and reception is out of the range of 0.1 m to 0.4 m, the first processing unit 15 causes the signal generator 11 and the transmission antenna 12 to be connected by the first matching unit 13 even if the control voltage Vs is changed. It is not possible to transition to a consistent state. For this reason, when the signal generator 11 and the transmission antenna 12 remain in a mismatched state, an excessive voltage is applied to each component of the first matching unit 13 due to a large reflected wave power from the transmission antenna 12. Although there is a possibility that a situation may occur, when the distance between transmission and reception is out of the range of 0.1 m to 0.4 m, the first processing unit 15 stops the transmission of power with medium power. Occurrence is prevented in advance.

  Thus, in the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the diode 31a that changes the capacitance value according to the control voltages Vsa1 and Vsb1 applied to the cathode terminal with the anode terminal as a reference. , 32a, a variable capacitor circuit 13a having a diode circuit DCa, and a variable capacitor circuit 13b having a diode circuit DCb made of diodes 31b, 32b. 15 controls the control voltages Vsa1 and Vsb1 to change (change) the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b, thereby matching the signal generator 11 and the transmission antenna 12. The matching process (first and second matching processes) is executed.

  Therefore, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, by changing the control voltages Vsa1 and Vsb1 (changing the control voltages Vsa1 and Vsb1), the first matching unit 13 Since the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b can be instantaneously changed (changed), the signal generator 11 and the transmission antenna 12 can be matched in a very short time. Thereby, even if the distance (distance between transmission and reception) between the power transmission device 2 and the power reception device 3 changes in real time, the matching state between the signal generation unit 11 and the transmission antenna 12 can be satisfactorily maintained. Power transmission to the power receiving device 3 can be continued in an efficient state. Further, since each variable capacitor circuit 13a, 13b is configured using a diode, the power transmission device 2 and the power reception device 3 can be reduced in size. In addition, since the control voltages Vsa1 and Vsb1 are continuously changed, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b of the first matching unit 13 can be changed to arbitrary capacitance values. As long as the power transmitting device 2 and the power receiving device 3 are moved within a moving range of 0.1 m to 0.4 m, the distance between the devices 2 and 3 (distance between transmission and reception) is any distance. Even so, the matching state between the signal generator 11 and the transmission antenna 12 can be maintained well, and power transmission to the power receiving device 3 can be continued in an efficient state.

Further, in the power transmission system 1 equipped with the power transmission device 2 and the power transmission device 2, the inductor 37a is connected in parallel to the diode circuit DCa, inductor 37 b are connected in parallel to the diode circuit DCb Therefore, the lower limit value of the capacitance change range for the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b is lowered. Therefore, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the signal generator 11 and the transmission antenna can be used even when the distance between the power transmission device 2 and the power reception device 3 (distance between transmission and reception) is short. 12 and the power transmission to the power receiving apparatus 3 can be executed in an efficient state.

  Further, in the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2 connected in series facing the first sub-diode circuit DCa1 are provided. Thus, the variable capacitor circuit 13a is configured, and the capacitance value Ctp of the variable capacitor circuit 13a is changed by applying the control voltage Vsa1 in common to the sub-diode circuits DCa1 and DCa2. Further, the variable capacitor circuit 13b is configured by including the first sub-diode circuit DCb1 and the second sub-diode circuit DCb2 connected in series so as to face the first sub-diode circuit DCb1, and each sub-diode circuit DCb1, DCb2 When the control voltage Vsb1 is applied in common to each of these, the capacitance value Cts of the variable capacitor circuit 13b is changed.

  Therefore, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the variable capacitor circuit 13a configures the diode 31a and the second sub diode circuit DCa2 that configure the first sub diode circuit DCa1. The AC signal S1 can be divided by half and applied to the diode 32a. In the variable capacitor circuit 13b, the diode 31b constituting the first sub-diode circuit DCb1 and the diode constituting the second sub-diode circuit DCb2 The AC signal S1 can be divided and applied to 32b. Therefore, when the power of the AC signal S1 is constant (the amplitude of the AC signal S1 is constant), the control voltage that can maintain the diodes 31a and 32a in the reverse bias state as compared with the configuration in which the diodes are not connected in series. The lower limit value of Vs can be lowered, thereby increasing the upper limit value of the capacitance change range for the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b. That is, the range of the distance between transmission and reception that can transmit power to the power receiving device 3 in the aligned state can be expanded.

  Further, in the power transmission device 2 and the power transmission system 1 including the power transmission device 2, each sub-diode circuit DCa1, DCa2, DCb1, and DCb2 is replaced with a plurality of diodes (diode 31a, diode 32a, diode 31b, and diode 32b). They are configured to be connected in parallel in the forward direction.

  Therefore, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, each of the sub-diode circuits DCa1, DCa2, DCb1, and DCb2 is converted into one diode (diode 31a, diode 32a, diode 31b, and diode 32b. ), The upper limit value of the capacitance change range for the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b can be increased. That is, the range of the distance between transmission and reception that can transmit power to the power receiving device 3 in the aligned state can be expanded. When the range of the distance between transmission and reception for transmitting power to the power receiving device 3 is narrow in the matching state, each sub-diode circuit DCa1, DCa2, DCb1, DCb2 is replaced by one diode (diode 31a, diode 32a, diode 31b, and diode 32b. ).

  Further, in the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the first processing unit 15 proceeds in a state where the signal generation unit 11 and the transmission antenna 12 are matched by executing the matching process. The wave power value W2a, the reflected wave power value W2b, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b calculated from the control voltage Vs, and the previously measured power transmission device 2 and power reception device 3 While calculating the transmission / reception distance based on the relationship between the transmission / reception distance and the output impedance Zout of the first matching unit 13 (relationship shown in FIG. 6), the calculated transmission / reception distance is the signal generation unit 11 and the transmission antenna 12. Are determined to be out of the matching range, the stop condition is satisfied, and the signal generator 11 is caused to stop generating the AC signal S1.

  Therefore, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the distance between the transmission and reception is out of the range of 0.1 m to 0.4 m, and the signal generation unit 11 and the transmission antenna 12 are matched. Even if the state that cannot be shifted to the state is reached, the first processing unit 15 stops the generation of the AC signal S1 from the signal generation unit 11, and thus may occur when the generation of the AC signal S1 is continued. It is possible to reliably prevent the continuous application of an excessive voltage to each component of the first matching unit 13 due to a large reflected wave power.

  Note that the present invention is not limited to the configuration shown in the above embodiment. For example, as indicated by broken lines in FIG. 1, the voltages Va and Vb at the connection points CNa and CNb in the variable capacitor circuits 13a and 13b of the first matching unit 13 (that is, applied to the diodes 31a, 32a, 31b, and 32b). The detection unit 16 that detects the applied voltage (see FIG. 5) in real time is provided, and the first processing unit 15 determines that the stop condition defined in advance based on the voltages Va and Vb in step 57 shown in FIG. It is also possible to adopt a configuration that determines whether or not the condition is satisfied and stops transmission (power transmission) of the medium power when the stop condition is satisfied.

  Specifically, the detection unit 16 detects the voltages Va and Vb and outputs voltage data Da and Db indicating the voltage values of the voltages Va and Vb to the first processing unit 15. When the power of the AC signal S1 output from the signal generator 11 increases, the amplitude of the AC signal S1 also increases. Therefore, depending on the increase in the amplitude, each diode 31a, 32a, 31b by applying the control voltage Vs. , 32b may not be maintained. In this case, the voltages Va and Vb do not reach the control voltage Vs output from the first processing unit 15. For this reason, it is defined as a stop condition that the voltages Va and Vb do not reach the control voltage Vs. In this configuration, in step 57, the first processing unit 15 compares the voltages Va and Vb having voltage values indicated by the voltage data Da and Db with the control voltages Vsa1 and Vsb1 corresponding to the voltages Va and Vb. When it is determined that any one of the voltages Va and Vb has not reached the corresponding control voltage Vsa1 and Vsb1, transmission of power (power transmission) at medium power is stopped assuming that the stop condition is satisfied.

  By adopting this configuration, according to the power transmission device 2 and the power transmission system 1 including the power transmission device 2, the reverse of each diode 31a, 32a, 31b, 32b due to the increase in the power of the AC signal S1. When the bias state is not maintained, that is, each of the diodes 31a, 32a, 31b, and 32b does not function as a variable capacitance diode, the signal generator 11 and the transmission antenna 12 cannot be shifted to the matching state. Even if it becomes a state, since the 1st process part 15 stops generation | occurrence | production of alternating current signal S1 from the signal generation part 11, when generation | occurrence | production of alternating current signal S1 is continued, it is in the big reflected wave electric power which may generate | occur | produce. Due to this, it is possible to reliably prevent the continuous application of an excessive voltage to each component of the first matching unit 13.

  In the power transmission device 2 and the power reception device 3 described above, the variable capacitor circuits 13a, 13b, 22a, and 22b are connected to the antennas (the transmission antenna 12 and the reception antenna 21) in parallel. Circuit 13a, 22a) and a variable capacitor circuit (variable capacitor circuit 13b, 22b) connected in series to the antenna (transmitting antenna 12 and receiving antenna 21). Each of the matching units 13 and 22 can be configured by any one of the circuits 13a and 22a) and any one of the variable capacitor circuits (variable capacitor circuits 13b and 22b). Further, it is variable with respect to a parallel circuit of an antenna (transmitting antenna 12 and receiving antenna 21) and a variable capacitor circuit (variable capacitor circuits 13a and 22a) and a series circuit composed of variable capacitor circuits (variable capacitor circuits 13b and 22b). Other variable capacitor circuits having the same configuration as the capacitor circuit 13a can be connected in parallel to form the so-called π-type matching units 13 and 22.

  Further, the variable capacitor circuits 13a, 13b, 22a, and 22b are replaced with one first sub-diode circuit DCa1 (1 or parallel to each other in the forward direction) as shown in FIG. 9 instead of the configuration shown in FIG. It can also be constituted by one diode circuit DCa constituted by a plurality of diodes 31a). In FIG. 9, the variable capacitor circuit 13a is described as an example, but the same configuration can be adopted for the other variable capacitor circuits 13b, 22a, and 22b.

  According to this configuration, the capacitance value Ctp of the variable capacitor circuits 13a and 22a and the capacitance value Cts of the variable capacitor circuits 13b and 22b can be increased with a simple configuration.

  In addition, the variable capacitor circuits 13a, 13b, 22a, and 22b are replaced with the one shown in FIG. 10 instead of the configuration shown in FIG. 5, and are composed of one or a plurality of diodes 31a connected in parallel in the forward direction. A third sub-diode circuit DCa3, and one or a plurality of diodes 31b connected in parallel in the forward direction and a third sub-diode circuit DCa3 and a fourth sub-diode circuit DCa4 connected in series in the forward direction. It is also possible to adopt a configuration in which a diode circuit is configured and the control voltages Vsa3 and Vsa4 are individually applied to the third sub-diode circuit DCa3 and the fourth sub-diode circuit DCa4. As described above, the third sub-diode circuit DCa3 and the fourth sub-diode circuit DCa4 to which the control voltages Vsa3 and Vsa4 are individually applied are connected in series in a state where they are separated in a DC manner through the capacitor 48a. To do. For the third sub-diode circuit DCa3 and the fourth sub-diode circuit DCa4, these circuits and their peripheral circuits (inductors 38a and 40a and resistors 41a and 43a) are the same as the first sub-diode circuit DCa1 and its peripheral circuits. For this reason, the same reference numerals are assigned to the same components, and redundant description is omitted. In FIG. 10, the variable capacitor circuit 13a is described as an example, but the same configuration can be adopted for the other variable capacitor circuits 13b, 22a, and 22b.

  According to this configuration, the AC signal S1 can be divided by half and applied to the diode 31a constituting the third sub-diode circuit DCa3 and the diode 31a constituting the fourth sub-diode circuit DCa4. The capacitance change range for the capacitance value Ctp of the entire capacitor circuit 13a can be expanded.

  Further, as for the variable capacitor circuits 13a, 13b, 22a and 22b, instead of the configuration shown in FIG. 5, as shown in FIG. 11, each diode 31a constituting the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2 is shown. 32a can be constituted by a plurality (two in this example) of diodes 31a and 32a connected in series in the forward direction. In addition, about the structure same as the structure shown in FIG. 5, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In this case, as shown in FIG. 11, the control voltage Vsa1 is applied to the connection point CNa of the first sub-diode circuit DCa1 and the second sub-diode circuit DCa2, and the first sub-diode circuit DCa1 is connected in series in the forward direction. The inductor 46a and the resistor 47a are connected to the connection point CNa1 of the two diodes 32a connected in series in the forward direction in the second sub-diode circuit DCa2 via the series circuit of the inductor 44a and the resistor 45a to the connection point CNa1 of the two diodes 31a. It is also possible to adopt a configuration in which the other control voltage Vsa11 is applied via the series circuit. In this configuration, each diode 31a in the first sub-diode circuit DCa1 connected in parallel between the inductor 38a and the inductor 44a, and each diode 32a in the second sub-diode circuit DCa2 connected in parallel between the inductor 39a and the inductor 46a, respectively. The control voltage Vsa11 is applied in common. Further, each diode 31a in the first sub-diode circuit DCa1 connected in parallel between the inductor 44a and the inductor 40a and each diode 32a in the second sub-diode circuit DCa2 connected in parallel between the inductor 46a and the inductor 40a are common. A control voltage (Vsa1−Vsa11) is applied to.

  In addition, a configuration in which only the control voltage Vsa1 is applied to the connection point CNa without applying the control voltage Vsa11 (in this configuration, the inductor 44a, the resistor 45a, the inductor 46a, and the resistor 47a are not required) is adopted. You can also. In FIG. 11, the variable capacitor circuit 13a is described as an example, but the same configuration can be adopted for the other variable capacitor circuits 13b, 22a, and 22b.

  Further, in order to further increase the distance between transmission and reception between the power transmission device 2 and the power reception device 3, the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b in the matching unit 13 of the power transmission device 2 are wider. It is necessary to change with. In this case, it may be possible to adopt a configuration that expands the capacitance variable range of the capacitance values Ctp and Cts of the variable capacitor circuits 13a and 13b. For example, like the matching unit 13 shown in FIG. Without changing the capacitance variable range of the variable capacitor circuit 13a itself, fixed capacitors (one or a plurality of capacitors (non-variable capacitors)) 63a, 64a having a fixed capacitance value Cco are added to or disconnected from the variable capacitor circuit 13a. It is also possible to adopt a configuration in which the capacity addition circuit 13c that can be connected is connected in parallel to the variable capacitor circuit 13a to expand the capacity variable range of the variable capacitor circuit 13a and the capacity addition circuit 13c as a whole.

  Specifically, as shown in FIG. 12, the capacitance adding circuit 13c includes, as an example, a series circuit of diodes 61a and 62a that are small electronic components as switching elements, and a fixed capacitor (one or a plurality of small electronic components). (Two in this example) fixed capacitors (non-variable capacitors)) 63a, 64a and a bias circuit 65a.

  As the diodes 61a and 62a, PIN (p-intrinsic-n Diode) diodes having a property of passing high-frequency alternating current during forward bias are used, and the diodes 61a and 62a are connected to each other's anode terminals (or to each other). The cathode terminals are connected in series with each other. Fixed capacitors 63a and 64a are connected to respective end portions of diodes 61a and 62a connected in series.

  The bias circuit 65a includes a series circuit of a resistor R1 and a coil L1 that are small electronic components, a series circuit of a resistor R2 and a coil L2 that are small electronic components, and a series circuit of a resistor R3 and a coil L3 that are small electronic components. Yes. The series circuit of the resistor R1 and the coil L1 includes an end point P1a defined at a connection point between one terminal of the series circuit of the diodes 61a and 62a (in this example, the cathode terminal of the diode 61a) and the fixed capacitor 63a, and a reference potential. Connected between and. The series circuit of the resistor R2 and the coil L2 includes an end point P2a defined at a connection point between the other terminal of the series circuit of the diodes 61a and 62a (in this example, the cathode terminal of the diode 62a) and the fixed capacitor 64a, and a reference potential. Connected between and. The series circuit of the resistor R3 and the coil L3 is connected to the end point P3a defined at the intermediate point of the series circuit of the diodes 61a and 62a (in this example, the connection point between the anode terminals of the diodes 34a and 35a). The control voltage Vsc1 output from the 1 processing unit 15 is supplied to the end point P3a.

  In the capacitance adding circuit 13c configured as described above, as shown in FIG. 12, one end of the fixed capacitor 63a (the non-connected end to the series circuit of the diodes 61a and 62a) is connected to one end of the variable capacitor circuit 13a. One end of the fixed capacitor 64a (the end of the diodes 61a and 62a that is not connected to the series circuit) is connected to the other end of the variable capacitor circuit 13a, thereby being connected in parallel to the variable capacitor circuit 13a.

  Further, the control voltage Vsc1 is a DC voltage, and the voltage value of the control voltage Vsc1 by the first processing unit 15 is always an on-voltage value (for example, 10V) that causes the diodes 61a and 62a to shift to the forward bias state. It is controlled to any one of the off-voltage values (for example, −35V) that always shifts 62a to the reverse bias state. That is, the control voltage Vsc1 is applied between both ends of the diodes 61a and 62a and functions as a bias voltage for controlling the on / off state of the diodes 61a and 62a.

  With this configuration, the series circuit of the diodes 61a and 62a shifts to an ON state (a low impedance state of about 0.5Ω) that passes (conducts) the AC signal S1 when the control voltage Vsc1 of the ON voltage value is supplied. The two fixed capacitors 63a and 64a are connected in parallel to the variable capacitor circuit 13a. On the other hand, the series circuit of the diodes 61a and 62a shifts to an off state (a high impedance state of about 0.8 pF) that blocks the passage (conduction) of the AC signal S1 when the control voltage Vsc1 of the off voltage value is supplied. Thus, the two fixed capacitors 63a and 64a are non-parallel connected to the variable capacitor circuit 13a (connected in a form that is not parallel connection, in other words, the parallel connection is released).

According to this configuration, when the control voltage Vsc1 of the off-voltage value is supplied from the first processing unit 15, the two fixed capacitors 63a and 64a are not connected in parallel to the variable capacitor circuit 13a (in the case of parallel connection). In other words, since the capacitance values of the fixed capacitors 63a and 64a are not added), the lower limit value and the upper limit of the capacitance variable range of the capacitance values of the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole. value, the lower limit value _{C LOW1} and the upper limit value _{C HIGH1} capacity variable range of the variable capacitor circuit 13a alone. On the other hand, when the control voltage Vsc1 of the ON voltage value is supplied from the first processing unit 15, the two fixed capacitors 63a and 64a are connected in parallel to the variable capacitor circuit 13a (the static capacitors 63a and 64a are statically connected). _Therefore , the lower limit value C _LOW2 of the capacitance variable range of the capacitance values of the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole is the capacitance of the variable capacitor circuit 13a alone. A value (C _LOW1 + Cco / 2) _obtained by adding (adding) the series composite capacitance value (Cco / 2) of the two fixed capacitors 63a and 64a to the lower limit value C _LOW1 of the variable range, so that the variable capacitor circuit 13a and the capacitance addition circuit capacity variable range upper limit value _{C HIGH2} the capacitance value of the whole 13c, the variable capacitor circuit 1 a single capacity variable range of the upper limit value _{C HIGH1} two fixed capacitors 63a, a series combined capacitance of the 64a (Cco / 2) was added (the added) value (an upper limit value _C HIGH1 + Cco / 2).

Therefore, by connecting the capacitance adding circuit 13c to the variable capacitor circuit 13a, the capacitance value of the variable capacitor circuit 13a and the capacitance adding circuit 13c as a whole is set to a capacitance defined by the lower limit value C _LOW1 and the upper limit value C _HIGH1. Since it can be changed within the variable range and can be changed within another capacitance variable range defined by the lower limit value C _LOW2 and the upper limit value C _HIGH2 , compared with the configuration of the variable capacitor circuit 13a alone, The capacity variable range can be expanded.

For example, when a specified fixed capacitor 63a, the series combined capacitance value 64a a (Cco / 2) less than the upper limit value _{C HIGH1} includes a capacity variable range defined by the lower limit value _{C LOW1} and the upper limit value _{C HIGH1,} the lower limit value _{C LOW2} And another capacity variable range defined by the upper limit value C _HIGH2 partially overlap each other, so that the variable capacity circuit 13a and the capacity addition circuit 13c as a whole can change the capacity variable range of the capacitance value. can be expanded to a range defined by a lower limit value _{C LOW1} and the upper limit value _{C HIGH2} be less than 2-fold greater than the 1 times the capacity variable range defined by a lower limit value _{C LOW1} and the upper limit value _{C HIGH1.}

Further, when the specified fixed capacitor 63a, the series combined capacitance value 64a a (Cco / 2) to the upper limit _{C HIGH1} includes a capacity variable range defined by the lower limit value _{C LOW1} and the upper limit value _{C HIGH1,} the lower limit value _{C LOW2} and Since another capacity variable range defined by the upper limit value C _HIGH2 is continuous, the capacity variable range of the capacitance value as the whole of the variable capacitor circuit 13a and the capacity addition circuit 13c is set to the lower limit value C _LOW1. and it can be expanded to a range defined by a lower limit value _{C LOW1} and the upper limit value _{C HIGH2} to be twice the capacity variable range defined by the upper limit value _{C HIGH1.}

The fixed capacitor 63a, when the specified series combined capacitance value 64a a (Cco / 2) to a value greater than the upper limit _{C HIGH1} includes a capacity variable range defined by the lower limit value _{C LOW1} and the upper limit value _{C HIGH1,} lower limit Although the variable capacitance range defined by C _LOW2 and the upper limit value C _HIGH2 becomes discontinuous, the variable capacitance circuit 13a and the capacitance addition circuit 13c as a whole have a capacitance variable range of the capacitance value as the lower limit value C. _LOW1 and (the range between the lower limit value _{C LOW1} and the upper limit value _{C HIGH1,} the range of the lower limit value _{C LOW2} and the upper limit value _{C HIGH2)} upper limit _C 2 fold scope with capacitive variable range defined by _HIGH1 to be expanded Can do.

  Although not shown, the configuration in which the capacitance adding circuit 13c is connected can be applied to the other variable capacitor circuit 13b of the first matching unit 13 and the variable capacitor circuits 22a and 22b in the second matching unit 22. Of course.

  Therefore, according to the power transmission device 2 adopting this configuration, the range in which power can be efficiently transmitted to the power reception device 3 while maintaining the matching state between the signal generation unit 11 and the transmission antenna 12 well ( The distance between the power transmission device 2 and the power reception device 3 can be increased.

  In addition, the capacitance adding circuit 13c may employ any of the configurations shown in FIGS. 13, 14, and 15 instead of the configuration shown in FIG.

  First, the capacitance adding circuit 13c shown in FIG. 13 will be described. The capacitance adding circuit 13c is configured by omitting the diode 62a and the series circuit of the resistor R2 and the coil L2 from the capacitance adding circuit 13c having the configuration shown in FIG. Note that the same components as those illustrated in FIG. 12 are denoted by the same reference numerals, and redundant description is omitted.

Also in this configuration, when the control voltage Vsc1 of the off voltage value is supplied from the first processing unit 15, the diode 61a as the switching element shifts to the off state. For this reason, since the two fixed capacitors 63a and 64a are switched to a non-parallel connection state with respect to the variable capacitor circuit 13a, the capacitance variable range of the capacitance value as a whole of the variable capacitor circuit 13a and the capacitance addition circuit 13c. lower and upper limits of, the lower limit value _{C LOW1} and the upper limit value _{C HIGH1} capacity variable range of the variable capacitor circuit 13a alone. On the other hand, when the control voltage Vsc1 having the on-voltage value is supplied from the first processing unit 15, the diode 61a shifts to the on state. For this reason, since the two fixed capacitors 63a and 64a are switched in parallel to the variable capacitor circuit 13a, the capacitance variable range of the capacitance values of the variable capacitor circuit 13a and the capacitance adding circuit 13c as a whole is switched. Is a range defined by the lower limit C _LOW2 (= C _LOW1 + Cco / 2) and the upper limit C _HIGH2 (= C _HIGH1 + Cco / 2).

  Therefore, even when the capacitance addition circuit 13c having the configuration shown in FIG. 13 is used, the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole are performed in the same manner as when the capacitance addition circuit 13c having the configuration shown in FIG. 12 is used. The capacitance variable range of the capacitance value can be expanded. Of course, instead of the configuration in which the diode 62a and the series circuit of the resistor R2 and the coil L2 are omitted, a configuration in which the series circuit of the diode 61a and the resistor R1 and the coil L1 is omitted may be adopted.

  Next, the capacitance adding circuit 13c shown in FIG. 14 will be described. This capacity addition circuit 13c omits the series circuit of the diodes 61a and 62a from the capacity addition circuit 13c having the configuration shown in FIG. 12, and replaces this with one MOS type FET (field effect transistor) which is a small electronic component. 66a is connected as a switching element. Note that the same components as those illustrated in FIG. 12 are denoted by the same reference numerals, and redundant description is omitted.

  In the capacitance addition circuit 13c shown in FIG. 14, the FET 66a is disposed between the fixed capacitor 63a and the fixed capacitor 64a by connecting the drain terminal to the fixed capacitor 63a and connecting the source terminal to the fixed capacitor 64a. Has been.

  Further, in the capacitance adding circuit 13c, the end point P1a defined at the connection point between the drain terminal of the FET 66a and the fixed capacitor 63a is controlled via the resistor R1 and the coil L1 of the bias circuit 65a connected to the end point P1a. The voltage Vsc2 is supplied, and the control voltage Vsc1 is supplied to the gate terminal of the FET 66a through the resistor R3 and the coil L3 of the bias circuit 65a connected to the end point P3a defined by the gate terminal. Further, the end point P2a defined at the connection point between the source terminal of the FET 66a and the fixed capacitor 64a is connected to the reference potential via the resistor R2 and the coil L2 of the bias circuit 65a connected to the end point P2a.

With this configuration, when the gate terminal is biased to a positive voltage by the control voltage Vsc1 and the drain terminal is biased to a positive voltage exceeding the voltage of the gate terminal by the control voltage Vsc2, the FET 66a is turned on. For this reason, since the two fixed capacitors 63a and 64a are connected in parallel to the variable capacitor circuit 13a, the variable capacitance range of the capacitance value as a whole of the variable capacitor circuit 13a and the capacitance addition circuit 13c is as follows. The range is defined by the lower limit value C _LOW2 (= C _LOW1 + Cco / 2) and the upper limit value C _HIGH2 (= C _HIGH1 + Cco / 2). On the other hand, when the positive voltage bias by the control voltage Vsc1 to the gate terminal is stopped, the FET 66a shifts to the OFF state. For this reason, since the two fixed capacitors 63a and 64a are not connected in parallel to the variable capacitor circuit 13a, the variable capacitance circuit 13a and the capacitance addition circuit 13c as a whole have a capacitance variable range of capacitance values. lower limit and upper limit, the lower limit value _{C LOW1} and the upper limit value _{C HIGH1} capacity variable range of the variable capacitor circuit 13a alone.

  Therefore, even when the capacitance addition circuit 13c having the configuration shown in FIG. 14 is used, the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole are performed in the same manner as when the capacitance addition circuit 13c having the configuration shown in FIG. 12 is used. The capacitance variable range of the capacitance value can be expanded.

  Next, the capacitance adding circuit 13c shown in FIG. 15 will be described. This capacity addition circuit 13c is a capacity addition circuit having a configuration shown in FIGS. 12, 13, and 14 (a configuration using a series circuit of two diodes, which are small electronic components, and a semiconductor switch element such as one diode or one FET). Unlike 13c, the relay 67a which is a small electronic component is used as a switching element. Note that the same components as those illustrated in FIG. 12 are denoted by the same reference numerals, and redundant description is omitted.

  In the capacity addition circuit 13c shown in FIG. 15, the series circuit of the diodes 61a and 62a is omitted from the capacity addition circuit 13c having the configuration shown in FIG. 12, and one relay 67a, which is a small electronic component, is connected as a switching element instead. Has been configured. Note that the same components as those illustrated in FIG. 12 are denoted by the same reference numerals, and redundant description is omitted.

  In the capacity addition circuit 13c shown in FIG. 15, the relay 67a has one terminal of its contact circuit connected to the fixed capacitor 63a and the other terminal of the contact circuit connected to the fixed capacitor 64a, whereby the fixed capacitor 63a. And the fixed capacitor 64a. In the relay 67a, one terminal of the coil is connected to the reference potential, and the control voltage Vsc1 is supplied (applied) to the other terminal of the coil via the resistor R1 constituting the bias circuit 65a.

With this configuration, when the control voltage Vsc1 is supplied to the relay 67a via the resistor R1, the relay 67a shifts to the on state (the contact circuit is closed). For this reason, since the two fixed capacitors 63a and 64a are connected in parallel to the variable capacitor circuit 13a, the variable capacitance range of the capacitance value as a whole of the variable capacitor circuit 13a and the capacitance addition circuit 13c is as follows. The range is defined by the lower limit value C _LOW2 (= C _LOW1 + Cco / 2) and the upper limit value C _HIGH2 (= C _HIGH1 + Cco / 2). On the other hand, when the supply of the control voltage Vsc1 is stopped, the relay 67a shifts to an off state (a state where the contact circuit is opened). For this reason, since the two fixed capacitors 63a and 64a are not connected in parallel to the variable capacitor circuit 13a, the variable capacitance circuit 13a and the capacitance addition circuit 13c as a whole have a capacitance variable range of capacitance values. lower limit and upper limit, the lower limit value _{C LOW1} and the upper limit value _{C HIGH1} capacity variable range of the variable capacitor circuit 13a alone.

  Therefore, even when the capacitance addition circuit 13c having the configuration shown in FIG. 15 is used, the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole are performed in the same manner as when the capacitance addition circuit 13c having the configuration shown in FIG. 12 is used. The capacitance variable range of the capacitance value can be expanded.

  In the configuration using the relay 67a as the switching element, the contact circuit of the relay 67a needs to be separated from other parts in the first matching unit 13 in a DC manner, unlike the configuration using the semiconductor switch element as the switching element. There is no. For this reason, in the configuration shown in FIG. 15, either one of the fixed capacitors 63a and 64a can be removed, and the end of the contact circuit connected to the one capacitor can be connected to the variable capacitor circuit 13a.

  In addition, the matching unit 13 shown in FIGS. 12 to 15 employs a configuration in which one capacitor addition circuit 13c is connected to the variable capacitor circuit 13a or the like in a state where it can be connected in parallel. However, the present invention is not limited to this. Alternatively, as shown in FIG. 16, a configuration in which a plurality of capacitance adding circuits 13c are connected in a state where they can be connected in parallel can be employed. According to this configuration, the control voltage Vsc1 supplied to each capacitance adding circuit 13c is individually controlled, and the on / off state of the switching elements constituting each capacitance adding circuit 13c is controlled, whereby the variable capacitor circuit 13a is controlled. Since the number of fixed capacitors (fixed capacitors constituting each capacitance addition circuit 13c) connected in parallel can be increased or decreased in stages, the capacitance values of the variable capacitor circuit 13a and the capacitance addition circuit 13c as a whole The capacity variable range can be further expanded.

DESCRIPTION OF SYMBOLS 1 Power transmission system 2 Power transmission apparatus 3 Power receiving apparatus 4 Battery 11 Signal generation part 12 Transmission antenna 13 1st matching part 13a, 13b Variable capacitor circuit 13c Capacity addition circuit 14 Power measurement part 15 1st process part 21 Reception antenna 22 2nd matching Unit 23 Rectifier 24 Second processor 31a, 31b, 32a, 32b Diode 37a, 37b Inductor DCa, DCb Diode circuit S1 AC signal V1 Induced voltage Vsa1, Vsb1, Vsc1, Vsc2 Control voltage

Claims (7)

A signal generation unit that generates an AC signal, a transmission antenna that receives the supply of the AC signal to generate an electromagnetic field, and a matching unit that is disposed between the signal generation unit and the transmission antenna. A power transmission device that transmits power to a power receiving device having a receiving antenna that generates an induced voltage and a voltage generation unit that generates a voltage to be supplied to a load based on the induced voltage,
The matching unit includes a variable capacitor circuit including a diode circuit configured by a variable capacitance diode that changes a capacitance value according to a reverse bias voltage applied to the cathode terminal with respect to the anode terminal,
A processing unit that performs matching processing for matching the signal generation unit and the transmission antenna by changing the capacitance value of the variable capacitor circuit by controlling the reverse bias voltage ;
A power transmission apparatus comprising: an inductor connected in parallel to the diode circuit and configured to lower a lower limit value of a capacitance change range for the capacitance value . The diode circuit is composed of a first sub-diode circuit composed of one or a plurality of the variable capacitance diodes connected in parallel in the forward direction and one or a plurality of the variable capacitance diodes connected in parallel in the forward direction to each other. And a second sub-diode circuit connected in series opposite to the first sub-diode circuit, and the reverse bias voltage is applied to each of the first sub-diode circuit and the second sub-diode circuit. that claim 1 Symbol placement of the power transmitting device. It said diode circuit, connected in parallel a plurality of said variable capacitance claims is composed of the diode 1 Symbol placement of the power transmitting device in the forward direction. The diode circuit is composed of one or a plurality of variable capacitance diodes connected in parallel in the forward direction and one or more variable capacitance diodes connected in parallel in the forward direction. And a fourth sub-diode circuit connected in series with the third sub-diode circuit in the forward direction, and the reverse bias voltage is applied to each of the third sub-diode circuit and the fourth sub-diode circuit. that claim 1 Symbol placement of the power transmitting device. A power measurement unit disposed between the signal generation unit and the matching unit to measure a traveling wave power value and a reflected wave power value;
The signal generator is configured to be able to control the output power value of the AC signal,
The processing unit is a capacitance value of the variable capacitor circuit calculated from the traveling wave power value, the reflected wave power value, and the reverse bias voltage in a state where the signal generation unit and the transmission antenna are matched. And calculating the inter-transmission / reception distance based on the relationship between the transmission / reception distance between the power receiving device and the output impedance of the matching unit, and the calculated inter-transmission / reception distance is the signal generation. wherein when the transmitting antenna is determined that out of the possible range matching the parts, the power transmission device according to any one of 4 claims 1 to stop generation of the AC signal to the signal generator. The power transmission according to any one of claims 1 to 5 , wherein the matching unit includes a capacitance addition circuit having a fixed capacitor and a switching element that switches parallel connection and non-parallel connection of the fixed capacitor to the variable capacitor circuit. apparatus. Contactless power transmission system and a power receiving device and the power transmitting apparatus according to any one of claims 1 to 6.

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