JP2020080601A - Impedance matching circuit and non-contact power supply system having impedance matching circuit - Google Patents

Abstract

To provide an impedance matching circuit for dramatically improving the calculation speed of the load impedance required for impedance matching and the matching amount, and the matching accuracy, and to provide a non-contact power supply system having the impedance matching circuit.SOLUTION: There is provided an impedance matching circuit that identifies only the amplitude component from first and second reflection coefficients obtained by a change element capable of changing the load side reflection coefficients, calculates the load impedance by a quadratic equation formed from a calculation formula of two amplitude components, computes the reactance amount of a variable reactance element required for target impedance matching for matching with the output impedance from the calculated load impedance, thus adjusting the impedance of the variable reactance element.SELECTED DRAWING: Figure 1

Description

  The present invention provides impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. The present invention relates to an impedance matching circuit and a contactless power feeding system having the impedance matching circuit.

  In recent years, for the purpose of improving the convenience of power transmission for charging, etc., a power transmitting side device having a power transmitting element for outputting power in a non-contact manner, and receiving power supplied from the power transmitting side device in a non-contact manner A non-contact power feeding system including a power receiving side device having the power receiving element has attracted attention.

  In non-contact power feeding, in order to perform the power transmission with the maximum transmission efficiency without power loss, it is necessary to match the output impedance of the power transmission side device and the load impedance of the power reception side device. Particularly in the case of a high frequency circuit, reflection occurs due to the mismatch between the output impedance and the load impedance, that is, both impedances, and the transmission efficiency is reduced, so that it is necessary to match both impedances.

  For example, the impedance matching circuit is composed of a circuit composed of lumped constants L and C or a distributed constant microstrip, and the circuit composed of lumped constants L and C is connected between the antenna and the amplifier circuit. ing. Thereby, the reflected power loss returning to power transmission is suppressed and the power transmission efficiency of the entire system is improved (see, for example, Patent Document 1).

  Further, an impedance matching circuit is described as a π matching circuit, which is connected between a drive source having a high-frequency signal source and a load, and a method of automatically matching impedance by applying a power supply voltage from a power supply is proposed. There is (for example, refer to Patent Document 2).

  In this matching circuit, based on the traveling wave component signal and the reflected wave component signal detected by the directional coupler, the phase detection circuit detects the phase difference between the reflected wave component signal and the traveling wave component signal as a reference. To detect. This phase difference is judged by the correction direction judgment circuit whether or not it has a lead or lag component of a predetermined angle. The variable capacitance control circuit increases or decreases the variable capacitance of the capacitor based on the determination result to match the output impedance of the drive source with the impedance of the load on the output terminal side.

  Further, in another contactless power transmission system, a matching circuit is provided, and the detection unit detects the AC signal input to the power transmission resonator. The impedance control unit matches the impedance of the power transmission resonator with the output impedance of the power supply based on the fluctuation of the AC signal detected by the detection unit (see, for example, Patent Document 3).

  Further, according to another wireless power transmission system, a matching circuit having a variable reactance element, a traveling wave/reflected wave extraction unit for extracting traveling wave voltage and reflected wave voltage, and a traveling wave/reflected wave extraction unit for extracting the traveling wave/reflected wave voltage. A reflection coefficient calculation unit that calculates a reflection coefficient from the traveling wave voltage and the reflected wave voltage, and calculates the input impedance from the relationship between the reflection coefficient, the impedance of the matching target, and the input impedance, and from the input impedance The position determining unit and the control value output unit for calculating the capacitance value distributed to the variable reactance element of the matching circuit and setting the reactance value of the reactance element, and the absolute value of the reflection coefficient is greater than a predetermined threshold value. If it is larger, the row used in the matching correction amount table is changed so as to change the configuration of the matching circuit, and the electromagnetic waves generated by the power transmitting antenna and the power receiving antenna through the configuration for automatically matching the impedance. There is disclosed a wireless power transmission system during electric automatic traveling, in which the load is supplied with electric power from the power source at the time of field coupling (for example, see Patent Document 4).

JP, 2005-56760, A JP, 2010-87845, A JP2012-135117A JP, 2005-122955, A

  However, in Patent Documents 1 to 3, it is necessary to prepare some matching circuits in advance and switch the optimum circuit by the switching circuit. It may take time and effort to combine the optimum matching circuit using the optimum algorithm from the voltage feedback. Since the load impedance to be matched is performed in an unknown state, the circuit becomes bulky and the optimum algorithm may not be secured. Since the impedance on the transmitting side and the impedance on the receiving side are not accurately measured, the matching accuracy and the adjustment range are limited, and impedance matching may not be achieved.

  Further, in Patent Document 4, when changing the configuration of the matching circuit, it is necessary to read the data corresponding to the change amount from the predetermined matching correction amount table, and there is a problem that the throughput of the processing takes time. there were. In particular, in an environment in which processing is required in a short time, such as when electric power is transmitted while the moving body is moving, the time required for such processing becomes an important issue. In particular, the correction amount required for matching differs depending on the load of the power receiving side device, but the value of the predetermined matching correction amount table is a list of discrete values, so there is a corresponding correction amount. If you don't, you might end up in an infinite loop.

  By the way, since the impedance is a parameter for an AC signal, it is a quotient of the signal voltage and the current and has two components of amplitude and phase. That is, it is a complex number. In addition, since the load impedance required for impedance matching is estimated based on the measurement of the complex reflection coefficient in any of the above prior arts, the phase component of the reflection coefficient is affected by the phase synchronization and the cable length. There is a problem that an estimation error is likely to occur and the reliability of impedance matching accuracy becomes low.

  The present invention is for solving the above problems, and an impedance matching circuit that dramatically improves the calculation speed of the load impedance and the matching amount necessary for impedance matching and the matching accuracy, and a non-contact circuit having the impedance matching circuit. The purpose is to provide a power supply system.

  In order to achieve the above object, an impedance matching circuit according to a first aspect of the present invention specifies only an amplitude component from a first reflection coefficient and a second reflection coefficient obtained by a change element capable of changing a load impedance on a load side. The load impedance is accurately calculated by the equation generated from the calculation formulas of the two amplitude components, and the reactance amount of the variable reactance element necessary for matching the target impedance is calculated from the calculated load impedance. The most important feature is to provide a matching circuit that adjusts the impedance of the device.

That is, an impedance that performs impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. A matching circuit,
An impedance changing unit that changes the load impedance on the load side by a changing element having a predetermined change amount,
An opening and closing unit that opens and closes the connection between the impedance and the power receiving element,
An opening and closing control unit that controls opening and closing of the opening and closing unit,
A detection unit that detects a voltage of a traveling wave from the power transmission power source and a voltage of a reflected wave from the load at both times of opening and closing,
The impedance changing unit, when the connection with the power receiving element is opened by the opening/closing unit, calculates a first reflection coefficient from the detected traveling wave and reflected wave to specify only an amplitude component, and When the connection to the power receiving element is closed by the opening/closing unit, the second reflection coefficient is calculated from the detected traveling wave and reflected wave to specify only the amplitude component, and the calculation of the two amplitude components is performed. With a quadratic equation generated from the equation, a calculation unit for calculating the estimated value of the load impedance,
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount,
It is characterized by having.

  According to this configuration, by providing an element that changes the load impedance on the load side and controlling the opening and closing of the connection with the power receiving element, it becomes possible to obtain two different reflection coefficients, and further, the two It is possible to estimate the load impedance by a quadratic equation of only the amplitude excluding the phase component of the reflection coefficient, that is, the scalar amount, and calculate the reactance amount necessary for matching the target impedance.

  Further, in order to achieve the above object, the impedance matching circuit according to the second invention detects voltages at two different points on the transmission line, and loads the load by a simultaneous equation generated from the magnitudes of the voltages at the two points. The most main feature is to provide a matching circuit that calculates impedance, calculates the reactance amount of the variable reactance element necessary to match the target impedance from the calculated load impedance, and adjusts the impedance of the variable reactance element. And

That is, an impedance that performs impedance matching in power transmission between the output impedance of a circuit including a power transmission power source and a power transmission element and the load impedance of a circuit including a load and a power reception element that is arranged to face the power transmission element in a non-contact manner. A matching circuit,
A detection unit that detects voltages at two different points on the transmission line having a predetermined length as a first detection voltage and a second detection voltage;
A calculator that calculates an estimated value of the load impedance by a simultaneous equation generated from the first detection voltage and the second detection voltage;
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount. Characterize.

  According to this configuration, the first detection voltage and the second detection voltage are obtained from two different points on the transmission line, the load impedance is calculated by the simultaneous equations, and the reactance amount necessary for matching the target impedance is calculated. It will be possible.

  In addition, you may make it provide the non-contact electric power feeding system which has the matching circuit concerning the said 1st invention or 2nd invention.

  The matching circuit and the contactless power feeding system of the present invention do not require calculation of the load impedance necessary for impedance matching and specification of the matching amount based on the calculated load impedance in advance in a data table to read out, and a simple equation is used for immediate calculation. As a result, the processing speed of impedance matching is dramatically improved, and rapid power transmission and power feeding can be achieved.

  Further, since the above equation excludes the phase component and generates only the amplitude component, the calculation accuracy of the load impedance is dramatically improved, and an efficient and highly effective power transmission and power supply matching circuit is provided. There is an effect that can be realized.

FIG. 1 is a diagram showing a block configuration diagram of an impedance matching circuit according to the first embodiment. FIG. 2 is a diagram showing a block configuration diagram of an impedance matching circuit according to the second embodiment. FIG. 3 is a diagram showing the concept of the voltage measurement position on the transmission line in the impedance matching circuit according to the second embodiment. FIG. 4 is a diagram showing a block configuration diagram of the contactless power feeding system according to the present invention. FIG. 5 is a schematic diagram showing an encounter state between a carrier vehicle equipped with a power receiving side device and a power transmitting side device. FIG. 6 is a schematic diagram showing an encounter state between a vehicle including a power receiving side device and a power transmitting side device. FIG. 7: is the figure which showed the mobile body provided with the power receiving side apparatus, and the power transmission side apparatus provided in the track, (a) is a side view which shows the correspondence of the said mobile body and the said power transmission side apparatus, (B) is a top view of the power transmission side apparatus arrange|positioned in the track.

  Hereinafter, in the present embodiment, a matching circuit including a primary coil as a power transmitting element and a secondary coil as a power receiving element will be described as an example. However, the matching circuit according to the present invention includes magnetic field coupling, electric field coupling, and radiation. Any type of power feeding system can be applied, and the shapes of the power transmitting element and the power receiving element are not limited to the coil.

<First Embodiment of Impedance Matching Circuit>
With reference to FIG. 1, 100 is an impedance matching circuit according to the first embodiment. The impedance matching circuit 100 is a circuit provided for performing impedance matching in power transmission between the output impedance of the power feeding side (power transmission power source) and the load impedance of the power receiving side (load), as described later. If the output impedance of the power feeding side and the load impedance of the power receiving side are not matched, the reflected wave generated by the power that cannot be consumed on the power receiving side interferes with the incident wave on the power feeding side, and a standing wave is generated. . Then, a loss of electric power generated by the standing wave occurs.

In the impedance matching circuit 100, the matching impedance (that is, the target impedance) is determined by the matching unit 107 with respect to the load impedance Z _L of the power receiving target serving as a load, as described later.

  An impedance changing unit 101 is connected between the load and the matching unit 107. Although the load is connected in parallel in the present embodiment, it may be connected in series. The impedance changing unit 101 may be connected to the impedance matching circuit 100 to connect an element that changes the load impedance, and may be, for example, a capacitor or a coil. The impedance of the element itself connected to the impedance changing unit 101 is known.

  The impedance changing unit 101 changes the load impedance by opening/closing the opening/closing unit 102. For example, the opening/closing unit 102 may open/close the connection with the secondary coil 19a (impedance matching circuit 100) with a switch. The opening and closing of the opening and closing unit 102 is controlled by an opening and closing control unit 103 which controls the opening and closing of the switch by a microcomputer according to a predetermined condition. The predetermined condition is, for example, when the opening/closing unit 102 is in an open state (OFF state) with respect to the impedance changing unit 101 in the initial state and the signal processing unit 105 described later acquires the data in the initial state, the impedance It suffices to bring the changing unit 101 into a closed state (on state).

  The detection unit 104 detects the voltage of the incident wave from the power supply side and the voltage of the reflected wave from the load side in real time. That is, the incident wave voltage vi is detected by the first detection unit 104a, and the reflected wave voltage vr is detected by the second detection unit 104b. The reflection coefficient is obtained from the ratio of the reflected wave voltage vr and the incident wave voltage vi. Therefore, the detection unit 104 detects two reflection coefficients depending on whether the impedance changing unit 101 is present or not depending on the opening/closing of the opening/closing unit 102.

The incident wave voltage vi and the reflected wave voltage vr detected by the detection unit 104 are subjected to analog-digital conversion processing by the AD conversion unit 105a of the signal processing unit 105, and then calculation for calculation of load impedance is performed by the calculation unit 105b. Run. Here, when the reflection coefficient when the impedance changing unit 101 is off is Γ ₁ , the load impedance is Z _L , and the target impedance Z ₀ , the following equations hold.

On the other hand, when the impedance changing unit 101 is on, the reflection coefficient is Γ ₂ , the load impedance is Z _L2 , the target impedance Z ₀ , and the amount of change in impedance when the impedance changing unit 101 is turned on to jΔX, When the real part of the load impedance Z _L is R and the imaginary part is jX, the following equation holds.

但し、

However,

By the way, the reflection coefficients Γ ₁ and Γ ₂ are both values including the amplitude value and the phase angle, but by including the phase angle, the reflection coefficients Γ ₁ and Γ ₂ are complex numbers. Then, due to the difficulty of phase estimation, the accuracy of estimation of the load impedance Z _L may decrease. Therefore, in order to extract only the magnitude of the reflection coefficient, the calculation unit 105b calculates the absolute values |Γ ₁ | and |Γ ₂ |. In addition, the impedance of the element that constitutes the impedance changing unit 101 is a known value. Therefore, the calculation unit 105b can derive the quadratic equation of the real part R from Expression 1 and Expression 2 as shown in Expression 3 below by the configuration of the impedance matching circuit 100 including the impedance changing unit 101. The constants a, b, c and p, q in the following mathematical formula 3 can be obtained from the calculated absolute values |Γ ₁ |, |Γ ₂ | and the amount of change in the impedance from jΔX.

Since there is a one-to-one correspondence between the load impedance and the reflection coefficient, the load impedance Z _L can be derived from the reflection coefficient by the expression 3 by providing the impedance changing unit 101 to control ON/OFF. It enables simple calculations.

Next, when the estimated value of the load impedance Z _L is calculated by the calculation unit 105b, the element of the matching circuit that matches the target impedance Z ₀ can be determined.

  The calculated matching amount is first converted by the adjusting unit 106 into an analog signal by the DA converting unit 106a. From there, the capacitance values of the variable capacitors Cx, Cy, Cz of the T-type, L-type or π-type circuit are calculated.

  The adjusting unit 106 sets a control voltage value according to the matching amount, and via the first driving unit 106b, the second driving unit 106c, and the third driving unit 106d based on the control voltage value corresponding to each capacitance value. Then, the first motor 106e, the second motor 106f, and the third motor 106g connected to the variable capacitors Cx, Cy, and Cz of the matching unit 107 are energized to perform impedance matching processing.

  With the above configuration, impedance matching can be performed by a simple calculation process. Therefore, for example, a data table indicating the relationship between the reflection coefficient and the control value as described above is set in advance, and each time the impedance matching process is performed, Processing such as reading the data table becomes unnecessary. Further, by providing the impedance changing unit 101 and intentionally calculating two different load impedances, it becomes possible to eliminate a phase angle that reduces the calculation accuracy, and a complicated process of reading the data table. Can be eliminated, so that the accuracy of calculation processing for executing impedance matching is improved and the throughput is also improved.

<Second Embodiment of Impedance Matching Circuit>
Referring to FIG. 2, 200 is an impedance matching circuit according to the second embodiment. Like the impedance matching circuit 100 according to the first embodiment, the impedance matching circuit 200 also performs impedance matching by a simple calculation process. The load impedance has a transmission line having a predetermined length and is calculated from voltages at two different points on the transmission line. That is, in the case of high frequency, on a transmission line such as a long coaxial cable or parallel conductor, the voltage is constant at any position if there is no reflected wave, but the voltage is constant on the power transmitting side and the power receiving side. Due to the matching, when a reflected wave is generated, the presence of the standing wave causes a mismatch in the amplitude value of the voltage at two different points on the transmission line as a distributed constant circuit. The present embodiment utilizes this property.

In the impedance matching circuit 200, the matching impedance (that is, the target impedance) is determined by the matching unit 204 with respect to the load impedance Z _L of the power receiving target serving as the load, as described later.

As shown in FIG. 3, the detection unit 201 detects two different voltage points on the transmission line W, that is, at two points, that is, at a distance X ₁ from the load and at a distance X ₂ from the load. To detect. The first voltage detection unit 201a detects the voltage of the point at the distance X ₁ , and the second voltage detection unit 201b detects the voltage of the point at the distance X 2 in real time.

The voltage at the two points detected by the detection unit 201 is subjected to analog-digital conversion processing by the AD conversion unit 202a of the signal processing unit 202, and then calculation for load impedance estimation is executed by the calculation unit 202b. Here, the voltage detected at X ₁ is V ₁ , the voltage detected at X ₂ is V ₂ , the incident wave voltage is V _i , the reflection coefficient of the transmission line is Γ _L , the phase constant is β, and the load is X ₁ When the reflection coefficient at a point distant from the load is Γ _L ^-2βX1 , and the reflection coefficient at a point distant from the load by X ₂ is Γ _L ^-2βX2 , the following two expressions are established.

Then, the incident wave voltage V _i is known, and from the general formula of the phase constant β, the two formulas 4 are established as simultaneous equations for estimating the reflection coefficient Γ _L of the transmission line. By the way, assuming that the load impedance is Z _L and the target impedance is Z ₀ , the following formula is established. That is, the load impedance Z _L can be estimated based on the detection of the voltages at the two points and the simultaneous equations based on the two equations (4).

Next, when the estimated value of the load impedance Z _L is calculated by the calculation unit 202b, the circuit element that matches the target impedance Z ₀ is calculated.

  The calculated matching amount is first converted by the adjusting unit 203 into an analog signal by the DA converting unit 203a. The converted matching amount is distributed to the capacitance values of the variable capacitors Cx, Cy, and Cz of the T-type circuit (or L-type or π-type) forming the matching unit 204. The capacitance values can be easily calculated if the sum of the variable capacitors Cx, Cy, Cz is the matching amount and the voltage value and the current value are known.

  The adjusting unit 203 sets a control voltage value according to the matching amount, and via the first driving unit 203b, the second driving unit 203c, and the third driving unit 203d based on the control voltage value corresponding to each capacitance value. Then, the first motor 203e, the second motor 203f, and the third motor 203g connected to the variable capacitors Cx, Cy, and Cz of the matching unit 204 are energized to perform impedance matching processing.

With the above configuration, impedance matching can be performed by a simple calculation process. Therefore, for example, a data table indicating the relationship between the voltage at an arbitrary point and the control value as described above is set in advance, and the impedance matching process is performed. Each time, processing such as reading the data table becomes unnecessary. That is, since the complicated process of reading the data table can be eliminated, the impedance matching can be executed by an analytical method with a small number of procedures, and the calculation processing accuracy and the throughput are improved. In the present embodiment, the voltage of two arbitrary points (X ₁ , X ₂ ) is detected by estimating the load impedance Z _L , but the number of detected points may be three or more. ..

  The contactless power feeding system using the matching circuit according to the present invention will be described below with reference to FIG. Note that, for convenience of description, in the present embodiment, a contactless power feeding system including the impedance matching circuit 100 according to the first embodiment as an impedance matching circuit will be described, but the impedance matching circuit 200 according to the second embodiment is also the same. It is the structure of. Further, the present embodiment exemplifies one embodiment of the non-contact power feeding system, and the non-contact power feeding system according to the present invention is not limited to this mode.

  Referring to FIG. 4, reference numeral 1 is a contactless power feeding system. The contactless power feeding system 1 includes a charging circuit unit 2, a power transmitting unit 3, a power transmitting head unit 4, a power receiving head unit 5, and a power receiving unit 6. The charging circuit unit 2, the power transmission unit 3, and the power transmission head unit 4 configure a power transmission side device A, and the power reception head unit 5 and the power reception unit 6 configure a power reception side device B. The power transmission side device A and the power reception side device B are separately provided in a state of being separated from each other.

  The charging circuit unit 2 of the power transmission side device A charges the power transmission side capacitor 9 charged via the power transmission side rectification circuit 8 by the power source 7 (power transmission power source) having a standard voltage of AC100/200V at a frequency of 50 Hz or 60 Hz, for example. It is provided as a power transmission side buffer unit. The power transmission side capacitor 9 is connected so as to be supplied with power from the power supply 7, and is constantly charged when energized by the power supply 7. The power transmission side capacitor 9 is connected to the power supply circuit 12 that configures the power transmission unit 3. The word "power feeding" is used synonymously with "charging" in the following description.

  The power transmission unit 3 includes a power supply circuit 12 connected to the power supply 7. The power supply circuit 12 is provided with a charging control unit 10 as a charging control circuit, an oscillation circuit 13 forming an inverter circuit, and a power transmission side control circuit unit 16. The power supply circuit 12 is provided with a power transmission side control circuit section 16 to which a pilot lamp 15 is connected. The power transmission side control circuit unit 16 turns on the pilot lamp 15 when receiving the power supply signal S1 from the communication circuit 17 described later.

  The power transmission head unit 4 includes a communication circuit 17 and a primary coil 18, and the communication circuit 17 uses the control signal S1 as a communication medium (radio wave, light, sound wave, ultraviolet ray, infrared ray or heat sensitive wave) from a communication control unit 20 described later. I am supposed to receive it. The primary coil 18 is connected to receive a current from the drive circuit 14 and generate a magnetic field.

  The power reception head unit 5 of the power reception side device B includes a power reception side rectifier circuit 19 and a communication control unit 20. The power receiving side rectifier circuit 19 has a secondary coil 19 a that receives power transmission from the primary coil 18 via the impedance matching circuit 100 by electromagnetic field coupling in the electromagnetic field coupling section. The communication controller 20 has a transmitter (not shown) that sends the control signal S1 to the communication circuit 17. The impedance matching circuit 100 is provided for automatically matching the impedance between the power source and the circuit side of the primary coil 18 by a mechanism described later. The coil of the impedance matching circuit 100, the primary coil 18 and the secondary coil 19a are all formed by a litz wire to enhance the Q value (Quality Factor).

  The power reception unit 6 includes a control detection circuit 22 and a power reception side control circuit unit 23, and sends the current from the power reception side rectification circuit 19 to the control detection circuit 22. The power receiving side control circuit unit 23 is connected so as to send the detection signal S3 from the control detection circuit 22 to the communication control unit 20. The control detection circuit 22 is connected to a power receiving side capacitor 24 as a power receiving target. The power receiving side capacitor 24 constitutes the power storage unit 11 and is charged by the combined power.

  The impedance matching circuit 100 is provided between the power transmission power supply 7 and the primary coil 18. The impedance matching circuit 100 may be provided between the secondary coil 19a and the load side.

  FIG. 5: is the figure which applied the non-contact electric power feeding system 1 to the mobile body (guide type conveyance vehicle) 25. As shown in FIG. The power transmission side device is housed in the power transmission casing 26 and fixed to the stationary member 27, and the power reception side device B is housed in the power reception casing 28 and mounted on the moving body 25 traveling on the floor W inside and outside the factory and inside and outside the warehouse. It

  The power receiving side capacitor 24, which is a power receiving target, is provided in the moving body 25, and is used to drive a drive motor (not shown) for driving wheels, which will be described later, and a steering motor 34 provided on the left and right of the steered wheels 33. .. The moving body 25 is used for unmanned operation for carrying various tools, parts or products (not shown) placed in factories or warehouses while traveling on the floor surface W. The power transmission side device A may be fixed to a stationary member 27 described later, and the power reception side device B may also be mounted on the moving body 25 by retrofitting.

  The moving body 25 has a rectangular chassis 30 having wheels 29 at four corners, and a drive controller 32 for connecting left and right electromagnetic sensors 31a and 31b is attached to the chassis 30. The drive control unit 32 is configured to receive power from the power receiving side capacitor 24 via the output control unit 32a. A dielectric 35 made of, for example, aluminum tape is attached to the floor surface W in a closed loop along a predetermined track. When the moving body 25 travels, the drive signals of the left and right electromagnetic sensors 31a and 31b control the drive of the drive motor and the steering motor 34 via the drive control unit 32.

  When the moving body 25 is traveling, the moving body 25 is brought close to the stationary member 27 and stopped, and the power transmission casing 26 is brought close to the power receiving casing 28 with a small gap G left.

  Along with this, the secondary coil 19 a of the power reception head unit 5 is positioned so as to face the primary coil 18 of the power transmission head unit 4, and the communication circuit 17 is positioned so as to correspond to the transmission unit of the communication control unit 20. At this time, the control detection circuit 22 detects the current value of the power receiving side capacitor 24, and when the threshold level of this current value is less than a predetermined value, the power receiving side control circuit section 23 activates the communication control section 20 and the communication control section 20. The communication circuit 17 is operated by the control signal S1 from the power supply circuit 12, and the charging control unit 10 is operated via the power transmission side control circuit unit 16 of the power supply circuit 12.

  As a result, the pilot lamp 15 is turned on, the power from the power transmission side rectifier circuit 8 is sent to the charging control unit 10 of the power supply circuit 12, and at the same time, the power stored in the power transmission side capacitor 9 by the power supply 7 is charged in the charging control unit. Sent to 10. The power from the power transmission side rectification circuit 8 and the power stored in the power transmission side capacitor 9 are high-frequency power of the combined power added by the charge control unit 10 and are passed through the oscillation circuit 13 and the drive circuit 14 to the primary coil 18 To excite the secondary coil 19a.

  That is, electromagnetic coupling occurs due to the electromagnetic induction phenomenon between the primary coil 18 and the secondary coil 19a, and power is transmitted from the primary coil 18 to the secondary coil 19a. At this time, the electric power generated by the secondary coil 19a generates a rectified direct current via the power receiving side rectifying circuit 19 and flows through the power receiving side capacitor 24 from the control detection circuit 22 to be charged.

  When the charge amount of the power receiving side capacitor 24 is full and the charging is completed, the control detection circuit 22 detects the threshold level of the current value. Along with this, the power receiving side control circuit unit 23 operates the power transmission side control circuit unit 16 via the communication control unit 20 and the communication circuit 17, turns off the pilot lamp 15, and sends a stop signal S4 to the charging control unit 10. Power transmission to the oscillation circuit 13 is stopped.

  When the charge amount of the power receiving side capacitor 24 is full, power is supplied from the power receiving side capacitor 24 via the output control unit 32a of the drive control unit 32 of the moving body 25, and the drive motor of the drive wheel and the steered wheel 33 are supplied. The guide type guided vehicle 25 runs on the floor surface W along the guide 35 detected by the left and right electromagnetic sensors 31a and 31b to carry tools and parts.

  FIG. 6 is a diagram in which the contactless power supply system 1 is applied to a vehicle 47 such as a passenger car. With the application to the vehicle 47, instead of the power receiving side capacitor 24 of the power receiving side device B, a power receiving side battery 48 having an electric capacity having a standard of, for example, 12V/23Ah×2 series is provided as a power receiving target. The power receiving side battery 48 is a normal battery installed in the hood 49 of the vehicle 47.

  In this case, the power transmission side device A is fixed to the stationary member 27, the power reception side device B is mounted on the vehicle 47, and the power reception side battery 48 is used for starting and driving an engine (not shown) mounted on the vehicle 47. .

  When the power receiving side battery 48 is charged, the vehicle 47 approaches the stationary member 27 and stops, and the power transmission casing 26 corresponds to the power receiving casing 28 by positioning. As a result, the communication control unit 20 operates, the communication circuit 17 is operated by the control signal S1, and the DC current from the power receiving side rectifying circuit 19 supplies power to the power receiving side battery 48 via the control detection circuit 22.

  Further, since the power transmitting side device A can be fixed to the stationary member 27 or the power receiving side device B can be mounted on the vehicle 47, each of the power transmitting side device A and the power receiving side device B can be independently traded. It can be manufactured and sold.

  Instead of the power transmission side capacitor 9 in the charging circuit unit 2, a small size and small capacity power transmission side battery may be provided as the power transmission side buffer unit. Since the battery on the power transmission side may be a small battery with a small capacity instead of a large battery with a large capacity, it contributes to weight reduction and cost reduction of the non-contact power feeding system 1. In consideration of this point, the power transmission side battery may be provided instead of the power transmission side capacitor 9. When the power transmission side battery is provided instead of the power transmission side capacitor 9, the power reception side battery may be installed instead of the power reception side capacitor 24.

  FIG. 7 is a diagram showing a moving body (vehicle) 25 including a power receiving side device B and a power transmitting side device A provided in a track. The power transmission side device A is embedded in the track 100A on the ground on which the moving body 25 travels (for example, inside a paved road), and the power receiving side device B is attached to the moving body 25. As described above, when the primary coil is energized by the power supply 7 (not shown in FIG. 6) while the moving body 25 such as a vehicle is traveling, electromagnetic field coupling is caused when the secondary coil 19a is encountered from the circuit side of the primary coil 18. , Power is transmitted from the circuit side of the primary coil 18 to the circuit side of the secondary coil 19a to supply power to the power receiving target.

  The primary coil 18 of the power transmission side device embedded in the track 100A has a laterally elongated elliptical shape from two linear parts arranged in parallel and an arc-shaped part that connects both ends of the linear part. The primary coils 18 are arranged at predetermined intervals along the traveling direction Rm of the track 100A. Below the primary coil 18 of the power transmission side device on the track 100A, a hard magnetic material such as ferrite is used for the purpose of preventing magnetic diffusion between the primary coil 18 and the secondary coil 19a and improving the coupling coefficient. A magnetism collecting plate (not shown) is arranged in close proximity to the primary coil 18.

  Since the primary coil 18 has a horizontally elongated elliptical shape, a large number of primary coils 18 are laid horizontally at a predetermined interval along the traveling direction Rm of the track 100A to secure a laying distance per single primary coil 18. The number of primary coils 18 can be reduced, and the coils can be arranged over a long distance. In this case, since the impedance matching circuit 100 having a coil is located within the range of the primary coil 18, the magnetic flux of the impedance matching circuit 100 for the primary coil 18 can be efficiently sent without leaking to the outside.

  The adjacent primary coils 18 are connected to each other via a switching element 100B (corresponding to a switching unit) by a wiring (corresponding to a connecting unit). The distance between adjacent primary coils 18, that is, the distance between the tip of one primary coil 18 and the rear end of the other primary coil 18 is, for example, an ellipse of the primary coil 18 along the traveling direction of the moving body 25. Set to 1/2 to twice the size. However, the separation distance can be set as desired according to the arrangement of the primary coil 18, the laying of the track 100A, the use environment, and the like.

  When the primary coil 18 and the secondary coil 19a encounter each other while the moving body 25 is traveling, the proximity sensor 100C (corresponding to the proximity detection unit) detects the encounter between the primary coil 18 and the secondary coil 19a, whereby the switching element 100B operates and the track 100A. Of the primary coils 18 adjacent to each other in the traveling direction Rm, one of the primary coils 18 is set to switch to the other.

  As described above, the secondary coil 19a is continuously resonated every time the secondary coil 19a sequentially encounters a large number of adjacent primary coils 18 as the moving body 25 travels in the traveling direction Rm. As a result, it is possible to continuously supply power when the moving body 25 is running.

  Specifically, the power receiving side device B including the impedance matching circuit 100 and the secondary coil 19a is attached to the rear surface side of the vehicle body 25a of the moving body 25 via a mounting plate.

  The power receiving side capacitor 24, which is a power receiving object, is connected to, for example, a battery cell 24A for charging, which is arranged in a hood of a vehicle, and is used as a drive motor for a vehicle starter or an air conditioning compressor or various electric components (not shown). It is supposed to be used for operations such as.

100, 200 Impedance matching circuit 101 Impedance changing unit
102 opening/closing unit 103 opening/closing control unit 104, 201 detection unit 105, 202 signal processing unit 106, 203 adjusting unit 107, 204 matching unit

  The present invention provides impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. The present invention relates to an impedance matching circuit and a contactless power feeding system having the impedance matching circuit.

  In recent years, for the purpose of improving the convenience of power transmission for charging, etc., a power transmitting side device having a power transmitting element for outputting power in a non-contact manner, and receiving power supplied from the power transmitting side device in a non-contact manner A non-contact power feeding system including a power receiving side device having the power receiving element has attracted attention.

  In non-contact power feeding, in order to perform the power transmission with the maximum transmission efficiency without power loss, it is necessary to match the output impedance of the power transmission side device and the load impedance of the power reception side device. Particularly in the case of a high frequency circuit, reflection occurs due to the mismatch between the output impedance and the load impedance, that is, both impedances, and the transmission efficiency is reduced, so that it is necessary to match both impedances.

  For example, the impedance matching circuit is composed of a circuit composed of lumped constants L and C or a distributed constant microstrip, and the circuit composed of lumped constants L and C is connected between the antenna and the amplifier circuit. ing. Thereby, the reflected power loss returning to power transmission is suppressed and the power transmission efficiency of the entire system is improved (see, for example, Patent Document 1).

  Further, an impedance matching circuit is described as a π matching circuit, which is connected between a drive source having a high-frequency signal source and a load, and a method of automatically matching impedance by applying a power supply voltage from a power supply is proposed. There is (for example, refer to Patent Document 2).

  In this matching circuit, based on the traveling wave component signal and the reflected wave component signal detected by the directional coupler, the phase detection circuit detects the phase difference between the reflected wave component signal and the traveling wave component signal as a reference. To detect. This phase difference is judged by the correction direction judgment circuit whether or not it has a lead or lag component of a predetermined angle. The variable capacitance control circuit increases or decreases the variable capacitance of the capacitor based on the determination result to match the output impedance of the drive source with the impedance of the load on the output terminal side.

  Further, in another contactless power transmission system, a matching circuit is provided, and the detection unit detects the AC signal input to the power transmission resonator. The impedance control unit matches the impedance of the power transmission resonator with the output impedance of the power supply based on the fluctuation of the AC signal detected by the detection unit (see, for example, Patent Document 3).

  Further, according to another wireless power transmission system, a matching circuit having a variable reactance element, a traveling wave/reflected wave extraction unit for extracting traveling wave voltage and reflected wave voltage, and a traveling wave/reflected wave extraction unit for extracting the traveling wave/reflected wave voltage. A reflection coefficient calculation unit that calculates a reflection coefficient from the traveling wave voltage and the reflected wave voltage, and calculates the input impedance from the relationship between the reflection coefficient, the impedance of the matching target, and the input impedance, and from the input impedance The position determining unit and the control value output unit for calculating the capacitance value distributed to the variable reactance element of the matching circuit and setting the reactance value of the reactance element, and the absolute value of the reflection coefficient is greater than a predetermined threshold value. If it is larger, the row used in the matching correction amount table is changed so as to change the configuration of the matching circuit, and the electromagnetic waves generated by the power transmitting antenna and the power receiving antenna through the configuration for automatically matching the impedance. There is disclosed a wireless power transmission system during electric automatic traveling, in which the load is supplied with electric power from the power source at the time of field coupling (for example, see Patent Document 4).

JP, 2005-56760, A JP, 2010-87845, A JP 2012-135117 A JP, 2005-122955, A

  However, in Patent Documents 1 to 3, it is necessary to prepare some matching circuits in advance and switch the optimum circuit by the switching circuit. It may take time and effort to combine the optimum matching circuit using the optimum algorithm from the voltage feedback. Since the load impedance to be matched is performed in an unknown state, the circuit becomes bulky and the optimum algorithm may not be secured. Since the impedance on the transmitting side and the impedance on the receiving side are not accurately measured, the matching accuracy and the adjustment range are limited, and impedance matching may not be achieved.

  Further, in Patent Document 4, when changing the configuration of the matching circuit, it is necessary to read the data corresponding to the change amount from the predetermined matching correction amount table, and there is a problem that the throughput of the processing takes time. there were. In particular, in an environment where a short-time process is required, such as when power is transferred while the mobile body is moving, the time required for the process is an important issue. In particular, the correction amount required for matching differs depending on the load of the power receiving side device, but the value of the predetermined matching correction amount table is a list of discrete values, so there is a corresponding correction amount. If you don't, you might end up in an infinite loop.

  By the way, since the impedance is a parameter for an AC signal, it is a quotient of a signal voltage and a current, and has two components of amplitude and phase. That is, it is a complex number. In addition, since the load impedance required for impedance matching is estimated based on the measurement of the complex reflection coefficient in any of the above prior arts, the phase component of the reflection coefficient is affected by the phase synchronization and the cable length. There is a problem that an estimation error is likely to occur and the reliability of the impedance matching accuracy becomes low.

  The present invention is for solving the above problems, and an impedance matching circuit that dramatically improves the calculation speed of the load impedance and the matching amount necessary for impedance matching and the matching accuracy, and a non-contact circuit having the impedance matching circuit. The purpose is to provide a power supply system.

  In order to achieve the above object, an impedance matching circuit according to a first aspect of the present invention specifies only an amplitude component from a first reflection coefficient and a second reflection coefficient obtained by a change element capable of changing a load impedance on a load side. The load impedance is accurately calculated by the equation generated from the calculation formulas of the two amplitude components, and the reactance amount of the variable reactance element necessary for matching the target impedance is calculated from the calculated load impedance. The most important feature is to provide a matching circuit that adjusts the impedance of the device.

That is, an impedance that performs impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. A matching circuit,
An impedance changing unit that changes the load impedance on the load side by a changing element having a predetermined change amount,
An opening and closing unit that opens and closes the connection between the impedance and the power receiving element,
An opening and closing control unit that controls opening and closing of the opening and closing unit,
A detection unit that detects a voltage of a traveling wave from the power transmission power source and a voltage of a reflected wave from the load at both times of opening and closing,
The impedance changing unit calculates a first reflection coefficient from the detected traveling wave and reflected wave to specify only an amplitude component when the connection with the power receiving element is opened by the opening/closing unit, and When the connection to the power receiving element is closed by the opening/closing unit, the second reflection coefficient is calculated from the detected traveling wave and reflected wave to specify only the amplitude component, and the calculation of the two amplitude components is performed. With a quadratic equation generated from the equation, a calculation unit for calculating the estimated value of the load impedance,
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount,
It is characterized by having.

  According to this configuration, by providing an element that changes the load impedance on the load side and controlling the opening and closing of the connection with the power receiving element, it becomes possible to obtain two different reflection coefficients, and further, the two It becomes possible to estimate the load impedance by a quadratic equation only for the amplitude excluding the phase component of the reflection coefficient, that is, for the scalar amount, and calculate the reactance amount necessary for matching the target impedance.

Incidentally, it is also possible to provide a contactless power supply system having a matching circuit according to prior Symbol onset bright.

  The matching circuit and the contactless power feeding system of the present invention do not require calculation of the load impedance necessary for impedance matching and specification of the matching amount based on the calculated load impedance in advance in a data table to read out, and a simple equation is used for immediate calculation. As a result, the processing speed of impedance matching is dramatically improved, and rapid power transmission and power feeding can be achieved.

  Further, since the above equation excludes the phase component and generates only the amplitude component, the calculation accuracy of the load impedance is dramatically improved, and an efficient and highly effective power transmission and power supply matching circuit is provided. There is an effect that can be realized.

FIG. 1 is a diagram showing a block configuration diagram of an impedance matching circuit according to an embodiment disclosed in this specification . FIG. 2 is a diagram showing a block configuration diagram of the contactless power feeding system disclosed in this specification . FIG. 3 is a schematic diagram showing an encounter state between a carrier vehicle including a power receiving side device and a power transmitting side device. FIG. 4 is a schematic diagram showing an encounter state between a vehicle including a power receiving side device and a power transmitting side device. FIG. 5 is a diagram showing a moving body including a power receiving side device and a power transmitting side device provided in a track, and (a) is a side view showing a correspondence relationship between the moving body and the power transmitting side device, (B) is a top view of the power transmission side apparatus arrange|positioned in the track.

  Hereinafter, in the present embodiment, a matching circuit configured by a primary coil as a power transmitting element and a secondary coil as a power receiving element will be described as an example, but the matching circuit according to the present invention includes magnetic field coupling, electric field coupling, and radiation. Any type of power feeding system can be applied, and the shapes of the power transmitting element and the power receiving element are not limited to the coil.

<Implementation form of the impedance matching circuit>
With reference to FIG. 1, 100 is an impedance matching circuit according to the first embodiment. The impedance matching circuit 100 is a circuit provided for performing impedance matching in power transmission between the output impedance of the power feeding side (power transmission power source) and the load impedance of the power receiving side (load), as described later. If the output impedance of the power feeding side and the load impedance of the power receiving side are not matched, the reflected wave generated by the power that cannot be consumed on the power receiving side interferes with the incident wave on the power feeding side, and a standing wave is generated. . Then, a loss of electric power generated by the standing wave occurs.

In the impedance matching circuit 100, the matching impedance (that is, the target impedance) is determined by the matching unit 107 with respect to the load impedance Z _L of the power receiving target serving as a load, as described later.

  An impedance changing unit 101 is connected between the load and the matching unit 107. Although the load is connected in parallel in the present embodiment, it may be connected in series. The impedance changing unit 101 may be connected to the impedance matching circuit 100 to connect an element that changes the load impedance, and may be, for example, a capacitor or a coil. The impedance of the element itself connected to the impedance changing unit 101 is known.

  The impedance changing unit 101 changes the load impedance by opening/closing the opening/closing unit 102. For example, the opening/closing unit 102 may open/close the connection with the secondary coil 19a (impedance matching circuit 100) with a switch. The opening and closing of the opening and closing unit 102 is controlled by an opening and closing control unit 103 which controls the opening and closing of the switch by a microcomputer according to a predetermined condition. The predetermined condition is, for example, when the opening/closing unit 102 is in an open state (OFF state) with respect to the impedance changing unit 101 in the initial state and the signal processing unit 105 described later acquires the data in the initial state, the impedance is changed. It suffices to bring the changing unit 101 into a closed state (on state).

  The detection unit 104 detects the voltage of the incident wave from the power supply side and the voltage of the reflected wave from the load side in real time. That is, the incident wave voltage vi is detected by the first detection unit 104a, and the reflected wave voltage vr is detected by the second detection unit 104b. The reflection coefficient is obtained from the ratio of the reflected wave voltage vr and the incident wave voltage vi. Therefore, the detection unit 104 detects two reflection coefficients depending on whether the impedance changing unit 101 is present or not depending on the opening/closing of the opening/closing unit 102.

The incident wave voltage vi and the reflected wave voltage vr detected by the detection unit 104 are subjected to analog-digital conversion processing by the AD conversion unit 105a of the signal processing unit 105, and then calculation for calculation of load impedance is performed by the calculation unit 105b. Run. Here, when the reflection coefficient when the impedance changing unit 101 is off is Γ ₁ , the load impedance is Z _L , and the target impedance Z ₀ , the following equations hold.

On the other hand, when the impedance changing unit 101 is on, the reflection coefficient is Γ ₂ , the load impedance is Z _L2 , the target impedance Z ₀ , and the amount of change in impedance when the impedance changing unit 101 is turned on to jΔX, When the real part of the load impedance Z _L is R and the imaginary part is jX, the following equation holds.

但し、

However,

By the way, the reflection coefficients Γ ₁ and Γ ₂ are both values including the amplitude value and the phase angle, but by including the phase angle, the reflection coefficients Γ ₁ and Γ ₂ are complex numbers. Then, due to the difficulty of phase estimation, the accuracy of estimation of the load impedance Z _L may decrease. Therefore, in order to extract only the magnitude of the reflection coefficient, the calculation unit 105b calculates the absolute values |Γ ₁ | and |Γ ₂ |. In addition, the impedance of the element that constitutes the impedance changing unit 101 is a known value. Therefore, the calculation unit 105b can derive the quadratic equation of the real part R from Expression 1 and Expression 2 as shown in Expression 3 below by the configuration of the impedance matching circuit 100 including the impedance changing unit 101. The constants a, b, c and p, q in the following mathematical formula 3 can be obtained from the calculated absolute values |Γ ₁ |, |Γ ₂ | and the amount of change in the impedance from jΔX.

Since there is a one-to-one correspondence between the load impedance and the reflection coefficient, the load impedance Z _L can be derived from the reflection coefficient by the expression 3 by providing the impedance changing unit 101 to control ON/OFF. It enables simple calculations.

Then, when the estimated value of the load impedance Z _L is calculated by the calculation unit 105b, the element of the matching circuit that matches the target impedance Z ₀ can be determined.

  The calculated matching amount is first converted by the adjusting unit 106 into an analog signal by the DA converting unit 106a. From there, the capacitance values of the variable capacitors Cx, Cy, Cz of the T-type, L-type or π-type circuit are calculated.

  The adjusting unit 106 sets a control voltage value according to the matching amount, and via the first driving unit 106b, the second driving unit 106c, and the third driving unit 106d based on the control voltage value corresponding to each capacitance value. Then, the first motor 106e, the second motor 106f, and the third motor 106g connected to the variable capacitors Cx, Cy, and Cz of the matching unit 107 are energized to perform impedance matching processing.

  With the above configuration, impedance matching can be performed by a simple calculation process. Therefore, for example, a data table indicating the relationship between the reflection coefficient and the control value as described above is set in advance, and each time the impedance matching process is performed, Processing such as reading the data table becomes unnecessary. Further, by providing the impedance changing unit 101 and intentionally calculating two different load impedances, it becomes possible to eliminate a phase angle that reduces the calculation accuracy, and a complicated process of reading the data table. Can be eliminated, so that the accuracy of calculation processing for executing impedance matching is improved and the throughput is also improved.

<Embodiment of non-contact power feeding system>
The present embodiment exemplifies one embodiment of the non-contact power feeding system, and the non-contact power feeding system according to the present invention is not limited to this mode. Referring to FIG. 2, reference numeral 1 is a contactless power feeding system. The contactless power feeding system 1 includes a charging circuit unit 2, a power transmitting unit 3, a power transmitting head unit 4, a power receiving head unit 5, and a power receiving unit 6. The charging circuit unit 2, the power transmission unit 3, and the power transmission head unit 4 configure a power transmission side device A, and the power reception head unit 5 and the power reception unit 6 configure a power reception side device B. The power transmission side device A and the power reception side device B are separately provided in a state of being separated from each other.

  The charging circuit unit 2 of the power transmission side device A charges the power transmission side capacitor 9 charged via the power transmission side rectification circuit 8 by the power source 7 (power transmission power source) having a standard voltage of AC100/200V at a frequency of 50 Hz or 60 Hz, for example. It is provided as a power transmission side buffer unit. The power transmission side capacitor 9 is connected so as to be supplied with power from the power supply 7, and is constantly charged when energized by the power supply 7. The power transmission side capacitor 9 is connected to the power supply circuit 12 that configures the power transmission unit 3. The word "power feeding" is used synonymously with "charging" in the following description.

  The power transmission unit 3 includes a power supply circuit 12 connected to the power supply 7. The power supply circuit 12 is provided with a charging control unit 10 as a charging control circuit, an oscillation circuit 13 forming an inverter circuit, and a power transmission side control circuit unit 16. The power supply circuit 12 is provided with a power transmission side control circuit section 16 to which a pilot lamp 15 is connected. The power transmission side control circuit unit 16 turns on the pilot lamp 15 when receiving the power supply signal S1 from the communication circuit 17 described later.

  The power transmission head unit 4 includes a communication circuit 17 and a primary coil 18, and the communication circuit 17 uses the control signal S1 as a communication medium (radio wave, light, sound wave, ultraviolet ray, infrared ray or heat sensitive wave) from a communication control unit 20 described later. I am supposed to receive it. The primary coil 18 is connected to receive a current from the drive circuit 14 and generate a magnetic field.

  The power reception head unit 5 of the power reception side device B includes a power reception side rectifier circuit 19 and a communication control unit 20. The power receiving side rectifier circuit 19 has a secondary coil 19a that receives power transmission from the primary coil 18 through the impedance matching circuit 100 by electromagnetic field coupling in the electromagnetic field coupling section. The communication controller 20 has a transmitter (not shown) that sends the control signal S1 to the communication circuit 17. The impedance matching circuit 100 is provided for automatically matching the impedance between the power source and the circuit side of the primary coil 18 by a mechanism described later. The coil of the impedance matching circuit 100, the primary coil 18 and the secondary coil 19a are all formed by a litz wire to enhance the Q value (Quality Factor).

  The power reception unit 6 includes a control detection circuit 22 and a power reception side control circuit unit 23, and sends the current from the power reception side rectification circuit 19 to the control detection circuit 22. The power receiving side control circuit unit 23 is connected so as to send the detection signal S3 from the control detection circuit 22 to the communication control unit 20. The control detection circuit 22 is connected to a power receiving side capacitor 24 as a power receiving target. The power receiving side capacitor 24 constitutes the power storage unit 11 and is charged by the combined power.

  The impedance matching circuit 100 is provided between the power transmission power supply 7 and the primary coil 18. The impedance matching circuit 100 may be provided between the secondary coil 19a and the load side.

FIG. 3 is a diagram in which the non-contact power feeding system 1 is applied to a moving body (guided guided vehicle) 25. The power transmitting side device A is housed in the power transmitting casing 26 and fixed to the stationary member 27, and the power receiving side device B is housed in the power receiving casing 28 and mounted on the moving body 25 traveling on the floor W inside and outside the factory and inside and outside the warehouse. To be done.

  The power receiving side capacitor 24, which is a power receiving target, is provided in the moving body 25, and is used to drive a drive motor (not shown) for driving wheels, which will be described later, and a steering motor 34 provided on the left and right of the steered wheels 33. .. The moving body 25 is used for unmanned operation for carrying various tools, parts or products (not shown) placed in a factory or a warehouse by traveling on the floor surface W. The power transmission side device A may be fixed to a stationary member 27 described later, and the power reception side device B may also be mounted on the moving body 25 by retrofitting.

  The moving body 25 has a rectangular chassis 30 having wheels 29 at four corners, and a drive controller 32 for connecting left and right electromagnetic sensors 31a and 31b is attached to the chassis 30. The drive control unit 32 is configured to receive power from the power receiving side capacitor 24 via the output control unit 32a. A dielectric 35 made of, for example, an aluminum tape is attached to the floor surface W in a closed loop along a predetermined track. When the moving body 25 travels, the drive signals of the left and right electromagnetic sensors 31a and 31b control the drive of the drive motor and the steering motor 34 via the drive control unit 32.

  When the moving body 25 is traveling, the moving body 25 is brought close to the stationary member 27 and stopped, and the power transmission casing 26 is brought close to the power receiving casing 28 with a small gap G left.

  Along with this, the secondary coil 19 a of the power reception head unit 5 is positioned so as to face the primary coil 18 of the power transmission head unit 4, and the communication circuit 17 is positioned so as to correspond to the transmission unit of the communication control unit 20. At this time, the control detection circuit 22 detects the current value of the power receiving side capacitor 24, and when the threshold level of this current value is less than a predetermined value, the power receiving side control circuit section 23 activates the communication control section 20 and the communication control section 20. The communication circuit 17 is operated by the control signal S1 from the power supply circuit 12, and the charging control unit 10 is operated via the power transmission side control circuit unit 16 of the power supply circuit 12.

  As a result, the pilot lamp 15 is turned on, the electric power from the power transmission side rectification circuit 8 is sent to the charging control unit 10 of the power supply circuit 12, and at the same time, the electric power stored in the power transmission side capacitor 9 by the power supply 7 is charged. Sent to 10. The power from the power transmission side rectification circuit 8 and the power stored in the power transmission side capacitor 9 are high-frequency power of the combined power added by the charging control unit 10, and the primary coil 18 via the oscillation circuit 13 and the drive circuit 14. To excite the secondary coil 19a.

  That is, electromagnetic coupling occurs due to the electromagnetic induction phenomenon between the primary coil 18 and the secondary coil 19a, and power is transmitted from the primary coil 18 to the secondary coil 19a. At this time, the electric power generated by the secondary coil 19a generates a rectified direct current through the power receiving side rectifying circuit 19 and flows through the power receiving side capacitor 24 from the control detection circuit 22 to be charged.

  When the charge amount of the power receiving side capacitor 24 is full and the charging is completed, the control detection circuit 22 detects the threshold level of the current value. Along with this, the power receiving side control circuit unit 23 operates the power transmission side control circuit unit 16 via the communication control unit 20 and the communication circuit 17, turns off the pilot lamp 15, and sends a stop signal S4 to the charging control unit 10. Power transmission to the oscillation circuit 13 is stopped.

  When the charge amount of the power receiving side capacitor 24 is full, power is supplied from the power receiving side capacitor 24 via the output control unit 32a of the drive control unit 32 of the moving body 25, and the drive motor of the drive wheel and the steered wheel 33 are supplied. The guide type guided vehicle 25 runs on the floor surface W along the guide 35 detected by the left and right electromagnetic sensors 31a and 31b to carry tools and parts.

  FIG. 4 is a diagram in which the contactless power supply system 1 is applied to a vehicle 47 such as a passenger car. With the application to the vehicle 47, instead of the power receiving side capacitor 24 of the power receiving side device B, a power receiving side battery 48 having an electric capacity having a standard of, for example, 12V/23Ah×2 series is provided as a power receiving target. The power receiving side battery 48 is a normal battery installed in the hood 49 of the vehicle 47.

  In this case, the power transmission side device A is fixed to the stationary member 27, the power reception side device B is mounted on the vehicle 47, and the power reception side battery 48 is used for starting and driving an engine (not shown) mounted on the vehicle 47. ..

  When the power receiving side battery 48 is charged, the vehicle 47 approaches the stationary member 27 and stops, and the power transmission casing 26 corresponds to the power receiving casing 28 by positioning. As a result, the communication control unit 20 operates, the communication circuit 17 is operated by the control signal S1, and the DC current from the power receiving side rectifying circuit 19 supplies power to the power receiving side battery 48 via the control detection circuit 22.

  Further, since the power transmitting side device A can be fixed to the stationary member 27 or the power receiving side device B can be mounted on the vehicle 47, each of the power transmitting side device A and the power receiving side device B can be independently traded. It can be manufactured and sold.

  Instead of the power transmission side capacitor 9 in the charging circuit unit 2, a small size and small capacity power transmission side battery may be provided as the power transmission side buffer unit. Since the battery on the power transmission side may be a small battery with a small capacity instead of a large battery with a large capacity, it contributes to weight reduction and cost reduction of the non-contact power feeding system 1. In consideration of this point, the power transmission side battery may be provided instead of the power transmission side capacitor 9. When the power transmission side battery is provided instead of the power transmission side capacitor 9, the power reception side battery may be installed instead of the power reception side capacitor 24.

  FIG. 5 is a diagram showing a moving body (vehicle) 25 including the power receiving side device B and the power transmitting side device A provided in the track. The power transmission side device A is embedded in the track 100A on the ground on which the moving body 25 travels (for example, inside a paved road), and the power receiving side device B is attached to the moving body 25. As described above, when the primary coil is energized by the power supply 7 (not shown in FIG. 6) while the moving body 25 such as a vehicle is traveling, electromagnetic field coupling is caused when the secondary coil 19a is encountered from the circuit side of the primary coil 18. , Power is transmitted from the circuit side of the primary coil 18 to the circuit side of the secondary coil 19a to supply power to the power receiving target.

  The primary coil 18 of the power transmission side device embedded in the track 100A has a horizontally elongated elliptical shape from two linear parts arranged in parallel and an arc-shaped part connecting both ends of the linear part, The primary coils 18 are arranged at predetermined intervals along the traveling direction Rm of the track 100A. Below the primary coil 18 of the power transmission side device on the track 100A, a hard magnetic material such as ferrite is used for the purpose of preventing magnetic diffusion between the primary coil 18 and the secondary coil 19a and improving the coupling coefficient. A magnetism collecting plate (not shown) is arranged in close proximity to the primary coil 18.

  Since the primary coil 18 has a horizontally long elliptical shape, a large number of primary coils 18 are laid horizontally at predetermined intervals along the traveling direction Rm of the track 100A to secure a laying distance per single primary coil 18. The number of primary coils 18 can be reduced, and the coils can be arranged over a long distance. In this case, since the impedance matching circuit 100 having a coil is located within the range of the primary coil 18, the magnetic flux of the impedance matching circuit 100 for the primary coil 18 can be efficiently sent without leaking to the outside.

  The adjacent primary coils 18 are connected to each other via a switching element 100B (corresponding to a switching unit) by a wiring (corresponding to a connecting unit). The distance between the adjacent primary coils 18, that is, the distance between the tip of one primary coil 18 and the rear end of the other primary coil 18 is, for example, an ellipse of the primary coil 18 along the traveling direction of the moving body 25. Set to 1/2 to twice the size. However, the separation distance can be set as desired according to the arrangement of the primary coil 18, the laying of the track 100A, the use environment, and the like.

  When the primary coil 18 and the secondary coil 19a encounter each other while the moving body 25 is traveling, the proximity sensor 100C (corresponding to the proximity detection unit) detects the encounter between the primary coil 18 and the secondary coil 19a, whereby the switching element 100B operates and the track 100A. Of the primary coils 18 adjacent to each other in the traveling direction Rm, one of the primary coils 18 is set to switch to the other.

  As described above, the secondary coil 19a is continuously resonated every time the secondary coil 19a sequentially encounters a large number of adjacent primary coils 18 as the moving body 25 travels in the traveling direction Rm. As a result, it is possible to continuously supply power when the moving body 25 is running.

  Specifically, the power receiving side device B including the impedance matching circuit 100 and the secondary coil 19a is attached to the rear surface side of the vehicle body 25a of the moving body 25 via a mounting plate.

  The power receiving side capacitor 24, which is a power receiving object, is connected to, for example, a battery cell 24A for charging arranged in the hood of a vehicle, and is used as a drive motor for a vehicle starter or an air conditioning compressor or various electric components (not shown). It is supposed to be used for operations such as.

100 impedance matching circuit 101 impedance changing unit
102 Opening/Closing Unit 103 Opening/Closing Control Unit 104 Detection Unit 105 Signal Processing Unit 106 Adjusting Unit 107 Matching Unit

Claims (10)

An impedance matching circuit that performs impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. And
An impedance changing unit that changes the load impedance on the load side by a changing element having a predetermined change amount,
An opening and closing unit that opens and closes the connection between the impedance changing unit and the power receiving element,
An opening and closing control unit that controls opening and closing of the opening and closing unit,
A detection unit that detects a voltage of a traveling wave from the power transmission power source and a voltage of a reflected wave from the load at both times of opening and closing,
The impedance changing unit, when the connection with the power receiving element is opened by the opening and closing unit, calculates the first reflection coefficient from the detected traveling wave and reflected wave to specify only the amplitude component, When the connection with the power receiving element is closed by the opening/closing unit, a second reflection coefficient is calculated from the detected traveling wave and reflected wave to specify only the amplitude component, and the amplitude component of the two amplitude components is determined. With a quadratic equation generated from the calculation formula, a calculation unit for calculating the estimated value of the load impedance,
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount. Characteristic impedance matching circuit. An impedance matching circuit that performs impedance matching in power transmission between an output impedance of a circuit including a power transmission power source and a power transmission element and a load impedance of a circuit including a load and a power receiving element that is arranged in a contactless manner facing the power transmission element. And
A detection unit that detects voltages at two different points on the transmission line having a predetermined length as a first detection voltage and a second detection voltage;
The estimated value of the load impedance is calculated by a simultaneous equation generated from the first detection voltage and the second detection voltage, the incident wave voltage on the transmission line, the phase constant, and the reflection coefficient at the two points. With the calculator
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount. Characteristic impedance matching circuit. A power transmission side device including at least a power transmission power source and a power transmission element, a load including at least a power receiving target, and a power reception side device including a power reception element that is arranged to face the power transmission element in a noncontact manner A contactless power feeding system having an impedance matching circuit for performing impedance matching in power transmission between an output impedance and a load impedance of the power receiving side device,
An impedance changing unit that changes the load impedance on the load side by a changing element having a predetermined change amount,
An opening and closing unit that opens and closes the connection between the impedance changing unit and the power receiving element,
An opening and closing control unit that controls opening and closing of the opening and closing unit,
A detection unit that detects a voltage of a traveling wave from the power transmission power source and a voltage of a reflected wave from the load at both times of opening and closing,
The impedance changing unit, when the connection with the power receiving element is opened by the opening and closing unit, calculates the first reflection coefficient from the detected traveling wave and reflected wave to specify only the amplitude component, When the connection with the power receiving element is closed by the opening/closing unit, the second reflection coefficient is calculated from the detected traveling wave and reflected wave to specify only the amplitude component, and the amplitude component of the two amplitude components is calculated. With a quadratic equation generated from the calculation formula, a calculation unit for calculating the estimated value of the load impedance,
In order to match the target impedance for matching the output impedance with the calculated load impedance, a matching unit having a variable reactance element,
From the calculated load impedance, the reactance amount of the variable reactance element required for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount,
Have
The power transmission side device is provided with a power transmission side buffer unit that is constantly charged when energized by the power transmission power source, and during the power transmission, the power transmission side buffer unit uses the power from the power transmission power source and the power from the power transmission side buffer unit. A non-contact power feeding system, wherein power is fed to a power receiving target of a power receiving side device. A power transmission side device including at least a power transmission power source and a power transmission element, a load including at least a power receiving target, and a power reception side device including a power reception element that is arranged so as to face the power transmission element in a non-contact manner. A contactless power feeding system having an impedance matching circuit for performing impedance matching in power transmission between an output impedance and a load impedance of the power receiving side device,
A detection unit that detects voltages at two different points on the transmission line having a predetermined length as a first detection voltage and a second detection voltage;
The estimated value of the load impedance is calculated by a simultaneous equation generated from the first detection voltage and the second detection voltage, the incident wave voltage on the transmission line, the phase constant, and the reflection coefficient at the two points. With the calculator
A matching unit having a variable reactance element to match a target impedance for matching the output impedance with the calculated load impedance;
From the calculated load impedance, the reactance amount of the variable reactance element necessary for the matching is calculated, and an impedance adjusting unit that adjusts the impedance of the variable reactance element based on the calculated reactance amount,
Have
The power transmission side device is provided with a power transmission side buffer unit that is always charged when energized by the power transmission power source, and at the time of the power transmission, by the power from the power transmission power source and the power from the power transmission side buffer unit, A non-contact power feeding system, wherein power is fed to a power receiving target of a power receiving side device.   The power transmission side buffer unit is at least one of a power transmission side capacitor or a power transmission side battery, and the power receiving target is provided as at least one of a power receiving side capacitor or a power receiving side battery The non-contact power feeding system according to claim 3 or 4.   The power transmission side device is fixed to a stationary member, the power reception side device is mounted on a guided vehicle that travels on a predetermined floor surface, and the power receiving target is provided for driving the guided vehicle. The contactless power feeding system according to claim 3, wherein the contactless power feeding system is provided.   5. The power transmission side device is fixed to a stationary member, the power reception side device is mounted on a vehicle, and the power receiving target is applied to drive the vehicle. The contactless power supply system described in 1.   The power transmission side device is provided in a track on which a moving body travels, the power receiving side device is attached to the moving body, and is configured to perform the power transmission when the moving body travels. The contactless power supply system according to claim 3, wherein   The power transmission element of the power transmission side device provided in the track has a horizontally elongated elliptical shape in which two linear parts arranged in parallel and an arc-shaped part connecting both ends of the linear part are integrated. The contactless power feeding system according to claim 8, wherein a plurality of the power transmitting elements are arranged on the track at a predetermined interval.   A plurality of the power transmission elements are laid on the track, and each of the plurality of power transmission elements includes a proximity detection unit that detects proximity of the moving body, a connection unit that connects mutually adjacent power transmission elements, and the movement. The body moves from the position where the power transmitting element and the power receiving element are opposed to each other, to the power transmitting element side adjacent in the traveling direction, and the proximity detecting unit of the adjacent power transmitting element closes the moving body. 10. When it detects, it has a switching part which switches the said electrically conductive power transmission element to the said adjacent power transmission element by operation|movement of the switching element interposed in the said connection part, The Claim 8 or Claim 9 characterized by the above-mentioned. Contactless power supply system.

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