Travel-time power supply system

Abstract

To provide a travel-time power supply system in which location-depending variations of power that an electric vehicle receives during traveling from a pair of power transmission electrodes serving as power transmission paths arranged along a travel path can be reduced.SOLUTION: A travel-time power supply system 1 includes a travel-time power supply device 2 including a pair of power transmission electrodes 20A, 20B which are arranged along a travel path 1a, and receive high frequencies from both ends and transmit the power, and an electric vehicle 3 which includes a pair of power reception electrodes 30A, 30B and can receive power supply from the pair of power transmission electrodes 20A, 20B as a result of electric field coupling with the pair of power transmission electrodes 20A, 20B during traveling on the travel path 1a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an in-motion power supply system that can wirelessly supply power to an electric vehicle while it is in motion from a power transmission means on the road side by using an electric field coupling method. [Background technology]

[0002] Conventionally, in-motion power transfer systems are known that can wirelessly supply power to a traveling electric vehicle from an in-motion power transfer device installed on a travel path (such as a road) using an electric field coupling method. Among these systems, a pair of power transmission electrodes is arranged along the travel path as a power transmission path (see, for example, Patent Document 1 and Non-Patent Document 1). High-frequency waves applied to one end of the pair of power transmission electrodes propagate toward the other end, and if a traveling electric vehicle is detected, power is supplied to the electric vehicle. The electric vehicle uses the received (supplied) power to charge its battery and drive its traction motor. This allows the electric vehicle to travel long distances continuously without stopping at charging spots. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-068077 [Non-patent literature]

[0004] [Non-Patent Document 1] Takefumi Shindo, Masakazu Shiromoto, Takashi Ohira, "Electrified roads with continuous wireless power supply to moving electric vehicles," Monthly Journal of Roads, Japan Road Association, December 2021, Vol. 969, P18-22 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the remaining power not received by the electric vehicle continues to propagate past the electric vehicle toward the other end. Once at the other end, unless properly terminated at the other end, it will turn back and return to the first end as a reflected high-frequency wave. As a result, the power waves traveling from one end to the other and the power waves traveling from the other end to the first end interfere with each other, strengthening each other where the two waves are in phase and weakening each other where they are out of phase. As a result, the power received by the electric vehicle can fluctuate significantly depending on its location. While it is possible to maintain the received power at a constant value by, for example, detecting the location of the electric vehicle and adjusting the load impedance on the electric vehicle, this is difficult to control. This fluctuation is particularly pronounced when the transmission path length from one end to the other is equal to or greater than one-quarter of the wavelength of the high-frequency wave. Even if the other end of the pair of power transmitting electrodes is properly terminated, power will still be wasted there.

[0006] The present invention has been made in view of the above circumstances, and its object is to provide an in-motion power supply system that can reduce location-dependent fluctuations in the power that a traveling electric vehicle receives from a pair of power transmission electrodes that serve as power transmission paths arranged along a travel path. [Means for solving the problem]

[0007] In order to achieve the above object, the in-motion power supply system described in claim 1 includes an in-motion power supply device that is arranged along a roadway and has a pair of power transmitting electrodes that are applied with high frequency waves from both ends and transmit the power, and an electric vehicle that has a pair of power receiving electrodes and can be supplied with power from the pair of power transmitting electrodes through electric field coupling with the pair of power receiving electrodes while traveling on the roadway.

[0008] A moving-in power supply system according to claim 2 is the moving-in power supply system according to claim 1, wherein the moving-in power supply device further includes a high-frequency oscillator that outputs a high-frequency reference signal, a first power amplifier that receives the high-frequency reference signal and outputs a first applied high-frequency wave among the high-frequency waves to be applied to one end of the pair of power transmitting electrodes, a first directional coupler that emits a first proportional wave proportional to a first reflected high-frequency wave that is transmitted from the one end of the pair of power transmitting electrodes toward the first power amplifier, and a second directional coupler that emits a first proportional wave proportional to a first reflected high-frequency wave that is transmitted from the other end of the pair of power transmitting electrodes toward the second power amplifier. a second directional coupler that emits a second proportional wave proportional to the second reflected high-frequency wave; a phase difference detector that detects the phase difference between the first proportional wave and the second proportional wave and outputs a phase difference signal corresponding to the phase difference; a variable phase shifter that receives the high-frequency reference signal and the phase difference signal and outputs a high-frequency phase-shifted reference signal that has the same frequency as the high-frequency reference signal and has a phase that is changed according to the phase difference signal; and a second power amplifier that receives the high-frequency phase-shifted reference signal and outputs a second applied high-frequency signal that is to be applied to the other end of the pair of power transmitting electrodes.

[0009] The in-motion power supply system of claim 3 is the in-motion power supply system of claim 2, wherein the in-motion power supply device further includes an amplitude difference detector that detects the amplitude difference between a third proportional wave proportional to the first applied high frequency wave and a fourth proportional wave proportional to the second applied high frequency wave and outputs an amplitude difference signal corresponding thereto, and the gain of the second power amplifier and / or the first power amplifier is controlled according to the amplitude difference signal. [Effects of the Invention]

[0010] The in-motion power supply system according to the present invention makes it possible to reduce location-dependent fluctuations in the amount of power received by an electric vehicle while it is in motion from a pair of power transmission electrodes that are arranged along the roadway and serve as a power transmission path. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a traveling power supply system according to an embodiment of the present invention. [Figure 2]3 is an enlarged schematic cross-sectional view of the electric vehicle viewed from the front side, showing the vicinity of a pair of power transmitting electrodes and a pair of power receiving electrodes in the in-motion power supply system of FIG. [Figure 3] 1 is an equivalent circuit of the in-motion charging system. [Figure 4] FIG. 2 is a schematic diagram of another example of the in-motion power supply system of the same. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described. As shown in Fig. 1 and Fig. 2, an in-motion power supply system 1 according to an embodiment of the present invention includes an in-motion power supply device 2 and an electric vehicle 3. The in-motion power supply device 2 includes a pair of power transmitting electrodes 20A, 20B as a power transmission path. The electric vehicle 3 also includes a pair of power receiving electrodes 30A, 30B.

[0013] The pair of power transmission electrodes 20A, 20B of the in-motion power supply device 2 is arranged along the travel path 1a. The pair of power transmission electrodes 20A, 20B may be buried under the travel path 1a or provided above the travel path 1a. In this application, the term "travel path" refers to the area on which the electric vehicle 3 travels, and refers to a road such as a highway if the electric vehicle 3 is an automobile, or to a railway with rails if the electric vehicle 3 is a railway vehicle. In this embodiment, losses due to conductors and dielectrics on the travel path 1a are assumed to be negligibly small.

[0014] The pair of power transmitting electrodes 20A, 20B receive high-frequency waves (specifically, a first applied high-frequency wave a1 and a second applied high-frequency wave a2) applied to both ends 201, 202, and transmit the power. Specifically, the pair of power transmitting electrodes 20A, 20B receive the first applied high-frequency wave a1 at one end 201 (the left end in FIG. 1 ) and the second applied high-frequency wave a2 at the other end 202 (the right end in FIG. 1 ). The first applied high-frequency wave a1 and the second applied high-frequency wave a2 are typically sinusoidal waves. The first applied high-frequency wave a1 propagates toward the other end 202, and the second applied high-frequency wave a2 propagates toward the one end 201. Furthermore, the pair of power transmitting electrodes 20A, 20B emit a first reflected high-frequency wave b1 from one end 201 and emit a second reflected high-frequency wave b2 from the other end 202. The first reflected high frequency wave b1 travels toward the first power amplifier 22 (which will be described in detail later) (i.e., in the opposite direction to the first applied high frequency wave a1), and the second reflected high frequency wave b2 travels toward the second power amplifier 27 (which will be described in detail later) (i.e., in the opposite direction to the second applied high frequency wave a2).

[0015] The pair of power receiving electrodes 30A, 30B of the electric vehicle 3 can be supplied with power from the pair of power transmitting electrodes 20A, 20B through electric field coupling with the pair of power transmitting electrodes 20A, 20B while the electric vehicle 3 is traveling on the travel path 1a. The power supplied to the pair of power receiving electrodes 30A, 30B is used to charge the battery or to drive the traveling motor.

[0016] The in-motion power supply device 2 further includes a high-frequency oscillator 21 , a first power amplifier 22 , a first directional coupler 23 , a second directional coupler 24 , a phase difference detector 25 , a variable phase shifter 26 , and a second power amplifier 27 .

[0017] The high-frequency oscillator 21 outputs a high-frequency reference signal s1. The frequency of the high-frequency reference signal s1 is not particularly limited, but may be, for example, 13.56 MHz in the ISM band.

[0018] The first power amplifier 22 receives the high-frequency reference signal s1 output by the high-frequency oscillator 21, amplifies the signal to a predetermined power, and outputs the first applied high-frequency signal a1. Note that this amplification also includes a type in which the input high-frequency reference signal s1 is inverted and then amplified.

[0019] The first directional coupler 23 emits a first proportional wave c1 proportional to the first reflected high frequency wave b1 traveling from one end 201 of the pair of power transmitting electrodes 20A and 20B toward the first power amplifier 22. In addition, in FIG. 1, the resistors indicated by reference numerals 23A (and 24A) are termination resistors.

[0020] The second directional coupler 24 emits a second proportional wave c2 that is proportional to the second reflected high-frequency wave b2 and travels from the other ends 202 of the pair of power transmitting electrodes 20A and 20B toward the second power amplifier 27.

[0021] The phase difference detector 25 detects the phase difference δ between the first proportional wave c1 and the second proportional wave c2 (i.e., the phase difference δ between the first reflected high-frequency wave b1 and the second reflected high-frequency wave b2) and outputs a corresponding phase difference signal s2. The phase difference detector 25 can be an analog multiplier or an exclusive OR circuit.

[0022] The variable phase shifter 26 receives the high-frequency reference signal s1 output by the high-frequency oscillator 21 and also receives the phase difference signal s2. The variable phase shifter 26 outputs a high-frequency phase-shifted reference signal s3 that has the same frequency as the high-frequency reference signal s1 but whose phase is changed in accordance with the phase difference signal s2. For example, the high-frequency phase-shifted reference signal s3 can be set to lead the high-frequency reference signal s1 by a phase shift amount φ in accordance with the phase difference δ indicated by the phase difference signal s2.

[0023] The second power amplifier 27 receives the high-frequency phase-shifted reference signal s3 output by the variable phase shifter 26, amplifies it to a predetermined power, and outputs the second applied high-frequency signal a2. Note that this amplification also includes a type in which the input output signal of the variable phase shifter 26 is inverted and then amplified. In this way, the second applied high-frequency signal a2 can be made to lead the first applied high-frequency signal a1 by the amount of phase shift φ, depending on the phase difference δ between the first reflected high-frequency signal b1 and the second reflected high-frequency signal b2.

[0024] Furthermore, the gains of the first power amplifier 22 and the second power amplifier 27 are usually set so that the amplitudes of the first applied high frequency wave a1 and the second applied high frequency wave a2 output by them are the same.

[0025] Next, the operation of the in-motion power supply system 1 will be explained below using mathematical expressions.

[0026] The first applied radio frequency wave a1 applied to one end 201 of the pair of power transmitting electrodes 20A and 20B and the first reflected radio frequency wave b1 reflected from one end 201 of the pair of power transmitting electrodes 20A and 20B are expressed in polar coordinate format by the following formulas (1) and (2), where j is the imaginary unit, the symbol || is the absolute value of a complex number (i.e., the amplitude of the radio frequency wave), and the symbol ∠ is the argument of the complex number (i.e., the phase of the radio frequency wave). TIFF2025126856000002.tif10170TIFF2025126856000003.tif10170

[0027] The second applied high frequency wave a2 applied to the other end 202 of the pair of power transmitting electrodes 20A and 20B and the second reflected high frequency wave b2 reflected from the other end 202 of the pair of power transmitting electrodes 20A and 20B are expressed in polar coordinate format by the following equations (3) and (4). TIFF2025126856000004.tif10170TIFF2025126856000005.tif10170

[0028] The phase difference δ between the first reflected high-frequency wave b1 and the second reflected high-frequency wave b2 is expressed by the following equation (5). TIFF2025126856000006.tif10170

[0029] The amount of phase shift φ that the second applied high frequency wave a2 leads relative to the first applied high frequency wave a1 is expressed by the following equation (6). TIFF2025126856000007.tif10170

[0030] As shown in the equivalent circuit of FIG. 3, the reference impedance of the transmission path of the pair of power transmitting electrodes 20A, 20B is z0, and the load impedance of the electric vehicle 3 viewed from the pair of power transmitting electrodes 20A, 20B is R0.

[0031] Furthermore, the electrical length from one end 201 of the pair of power transmitting electrodes 20A, 20B to the electric vehicle 3 is defined as θ1, and the electrical length from the other end 202 of the pair of power transmitting electrodes 20A, 20B to the electric vehicle 3 is defined as θ2. The electrical lengths θ1 and θ2 vary depending on the position of the electric vehicle 3. For example, if the frequency of the high-frequency reference signal s1 is 13.56 MHz and the wavelength shortening rate of the roadway 1a is 1.5, the wavelength of the roadway 1a is shortened by the wavelength shortening rate from a wavelength of approximately 22.12 m in free space to 14.75 m. In this case, for example, if the distance from one end 201 of the pair of power transmitting electrodes 20A, 20B to the electric vehicle 3 is 7.375 m, the electrical length θ1 is 180°. If the distance from the other end 202 of the pair of power transmitting electrodes 20A, 20B to the electric vehicle 3 is 14.75 m, the electrical length θ2 is 360°.

[0032] In a pair of power transmitting electrodes 20A and 20B, the first applied high frequency wave a1 and the second applied high frequency wave a2 can be linearly linked to the first reflected high frequency wave b1 and the second reflected high frequency wave b2 using an S matrix, as shown in the following equation (7). TIFF2025126856000008.tif21170

[0033] The above S matrix can be expressed as in the following equation (8). TIFF2025126856000009.tif15170

[0034] Here, S' is a matrix indicating the phase rotation of the first applied high-frequency wave a1 from one end 201 to the electric vehicle 3 and the phase rotation of the second applied high-frequency wave a2 from the other end 202 to the electric vehicle 3 in the pair of power transmitting electrodes 20A, 20B, or the phase rotation of the first reflected high-frequency wave b1 from the electric vehicle 3 to one end 201 and the phase rotation of the second reflected high-frequency wave b2 from the electric vehicle 3 to the other end 202, and is expressed by the following equations (9) to (9''). TIFF2025126856000010.tif46170Note that the following equations (10) and (10´) naturally hold true. TIFF2025126856000011.tif21170

[0035] S'' is a matrix found by regarding the power feeding section 203, in which only the load impedance R0 looking at the electric vehicle 3 exists, as a port circuit network, with the length of the transmission line in the pair of power transmitting electrodes 20A, 20B set to zero.

[0036] S" can be found as follows. That is, the feed section 203 directly sees the load impedance R0 from both ends. Then, the Z matrix is ​​expressed by the following equation (11). TIFF2025126856000012.tif21170 Here, the electric vehicle 3 (more specifically, the pair of power receiving electrodes 30A, 30B) is configured so that the load impedance R0 is half the reference impedance z0, as shown in the following equation (12). TIFF2025126856000013.tif15170Then, S'' becomes as shown in the following equation (13). TIFF2025126856000014.tif30170

[0037] Therefore, the above formula (8) becomes as shown in the following formula (14) by formulas (9) and (13). TIFF2025126856000015.tif41170

[0038] Therefore, the above (7) becomes as shown in the following equation (15) using equation (14). TIFF2025126856000016.tif21170

[0039] According to equation (15), taking equations (10) and (10') into consideration, the amplitudes of the first reflected high-frequency wave b1 and the second reflected high-frequency wave b2 are as shown in equations (16) and (17) below. TIFF2025126856000017.tif26170TIFF2025126856000018.tif26170

[0040] Comparing equations (16) and (17), it is clear that the amplitudes of the first reflected high-frequency wave b1 and the second reflected high-frequency wave b2 are equal regardless of the electrical lengths θ1 and θ2 (that is, regardless of the position where the electric vehicle 3 is traveling).

[0041] On the other hand, the complex ratio between the first reflected high-frequency wave b1 and the second reflected high-frequency wave b2 is expressed by the following equation (18). TIFF2025126856000019.tif41170

[0042] When this is expressed as a phase difference between the left and right using equation (5), it is expressed by the following equation (19). TIFF2025126856000020.tif15170

[0043] Here, as expressed by the following equation (20), the variable phase shifter 26 controls the phase shift amount φ so that it differs from the phase difference δ by 180°. TIFF2025126856000021.tif10170Note that although equation (20) uses -π, advancing the phase by 180° is the same as delaying it by 180°, so it can also be set to +π.

[0044] In this case, the second applied high frequency wave a2 has a phase leading edge over the first applied high frequency wave a1, as expressed by equation (21). TIFF2025126856000022.tif10170

[0045] Furthermore, as expressed by the following equation (22), the first power amplifier 22 and the second power amplifier 27 are set so that the amplitudes of the first applied high frequency signal a1 and the second applied high frequency signal a2 output by them are the same. TIFF2025126856000023.tif10170

[0046] Therefore, the second applied high frequency a2 is expressed by the following equation (23). TIFF2025126856000024.tif10170

[0047] By substituting Equation (23) into Equation (16), the amplitude of the first reflected high frequency wave b1 is expressed as shown in the following Equation (24). TIFF2025126856000025.tif30170Furthermore, when equations (9') and (9'') are substituted into equation (24), the amplitude of the first reflected high frequency b1 becomes zero as shown in the following equation (25). TIFF2025126856000026.tif41170

[0048] Similarly, the amplitude of the second reflected high frequency b2 becomes zero as shown in the following equation (26). TIFF2025126856000027.tif10170

[0049] In this way, by configuring the electric vehicle 3 as shown in equation (12), controlling the phase shift amount φ as shown in equation (20), and setting the first power amplifier 22 and the second power amplifier 27 as shown in equation (22), the first applied high frequency wave a1 output by the first power amplifier 22 and the second applied high frequency wave a2 output by the second power amplifier 27 will not be reflected no matter where the electric vehicle 3 is located, and all of the power will be received by the electric vehicle 3. Therefore, the power received by the electric vehicle 3 will not vary depending on the location. Furthermore, since it is not necessary to know the location of the electric vehicle 3, no separate means for doing so is required.

[0050] Next, a case where the configuration of the electric vehicle 3 has an error with respect to that shown in equation (12) will be described.

[0051] If the error of the load impedance R0 is written as ζ, the load impedance R0 is expressed as in the following equation (27). TIFF2025126856000028.tif15170

[0052] In this case, the above equation (11) shifts and becomes the following equation (28). TIFF2025126856000029.tif21170

[0053] If the Z matrix of equation (28) is converted into a linearly approximated S matrix by assuming that the error ζ is sufficiently small compared to the reference impedance z0, that is, |ζ|<< z0, the result is given by the following equation (29). TIFF2025126856000030.tif30170

[0054] Accordingly, the above equations (14), (15), and (16) become the following equations (30), (31), and (32), respectively. TIFF2025126856000031.tif21170TIFF2025126856000032.tif21170TIFF2025126856000033.tif21170

[0055] Applying equations (9') and (9'') to this, and then applying equation (23) to it, we obtain the following equation (33). TIFF2025126856000034.tif21170

[0056] Since equation (33) represents the amplitude reflectance at one end 201 of the pair of power transmitting electrodes 20A and 20B, it can be converted to power reflectance by squaring equation (33). For example, if the absolute value of the error |ζ| is within 20% of the target value of the load impedance R0, the amplitude reflectance can be kept below 10%. Therefore, the power reflectance can be kept below 1%. Similarly, the amplitude reflectance at the other end 202 of the pair of power transmitting electrodes 20A and 20B can be calculated using equation (17), and the same result as equation (33) will be obtained.

[0057] Next, a case where the phase shift amount φ has an error with respect to that shown in equation (20) will be described.

[0058] If the phase errors caused by the phase difference detector 25 and the variable phase shifter 26 are collectively written as ψ, the controlled phase shift amount φ deviates from equations (20) and (21) and becomes as shown in the following equation (34). TIFF2025126856000035.tif21170In this case, equation (16) changes to the following equation (35). TIFF2025126856000036.tif30170 That is, the amplitude reflectance at one end 201 of the pair of power transmitting electrodes 20A and 20B is expressed by the following formula (36). TIFF2025126856000037.tif21170

[0059] Since Equation (36) is the amplitude reflectance, it can be converted to power reflectance by squaring it. For example, if the phase error ψ is within ±10°, the amplitude reflectance is 8.7% or less, and the power reflectance is 0.76% or less, which is kept below 1%. Furthermore, if the phase error ψ is within ±20°, the amplitude reflectance is 17% or less, and the power reflectance is kept below 3.0%. Similarly, the amplitude reflectance at the other end 202 of the pair of power transmitting electrodes 20A and 20B can be calculated using Equation (17), and the same result as Equation (36) is obtained.

[0060] Next, a description will be given of a moving-in power supply system 1' in which the amplitudes of the first applied high-frequency wave a1 and the second applied high-frequency wave a2 output by the first power amplifier 22 and the second power amplifier 27 are made the same as shown in equation (22), even if a difference occurs between the initial settings of the first power amplifier 22 and the second power amplifier 27 due to large changes in ambient temperature, aging, etc. The moving-in power supply system 1' has the same configuration and operates in the same way as the moving-in power supply system 1 described above, except for the points described below.

[0061] As shown in FIG. 4, the in-motion power supply device 2' of the in-motion power supply system 1' includes an amplitude difference detector 28. The amplitude difference detector 28 detects the amplitude difference between the third proportional wave d1 proportional to the first applied high-frequency wave a1 and the fourth proportional wave d2 proportional to the second applied high-frequency wave a2, and outputs a corresponding amplitude difference signal s4. The second power amplifier 27 receives the amplitude difference signal s4 and controls the gain of the second applied high-frequency wave a2 in response to the amplitude difference signal s4 so that the second applied high-frequency wave a2 satisfies equation (22). Specifically, if |a1|<|a2|, the gain of the second power amplifier 27 is reduced; if |a1|=|a2|, the gain of the second power amplifier 27 is maintained; and if |a1|>|a2|, the gain of the second power amplifier 27 is increased. This control is constantly repeated to maintain |a1|-|a2| at zero. It should be noted that instead of or in addition to controlling the gain of the second power amplifier 27, the gain of the first power amplifier 22 can be controlled by the amplitude difference detector .

[0062] The above-described configuration of the in-motion power supply system 1 or 1' makes it possible to reduce fluctuations depending on the location in the power received by the traveling electric vehicle 3 from the pair of power transmission electrodes 20A, 20B.

[0063] The above describes an in-motion power supply system according to an embodiment of the present invention. However, the present invention is not limited to the above-described embodiment, and various design modifications are possible within the scope of the claims. [Explanation of symbols]

[0064] 1.1´ In-motion charging system 1a Running track 2, 2´ In-motion power supply device 20A, 20B: A pair of power transmission electrodes 201 One end of a pair of power transmission electrodes 202 the other end of the pair of power transmitting electrodes 203 Power supply part 21 High-frequency oscillator 22 First power amplifier 23 First directional coupler 23A terminating resistor 24 Second directional coupler 24A terminating resistor 25 Phase difference detector 26 Variable Phase Shifter 27 Second power amplifier 28 Amplitude Difference Detector 3 Electric vehicles 30A, 30B A pair of receiving electrodes a1 First applied high frequency a2 2nd applied high frequency b1 First reflected high frequency b2 second reflected high frequency c1 1st proportional wave c2 second proportional wave d1 3rd proportional wave d2 4th proportional wave s1 high frequency reference signal s2 phase difference signal s3 high frequency phase shift reference signal s4 amplitude difference signal R0 Load Impedance z0 reference impedance θ1 Electrical length from one end of the pair of power transmission electrodes to the electric vehicle θ2 Electrical length from the other end of the pair of power transmission electrodes to the electric vehicle φ Phase shift of the second applied high frequency wave relative to the first applied high frequency wave δ Phase difference between the first proportional wave and the second proportional wave (phase difference between the first reflected high frequency wave and the second reflected high frequency wave)

Claims

1. a moving power supply device including a pair of power transmission electrodes that are arranged along a travel path and that receive high frequency waves from both ends and transmit the power; an electric vehicle including a pair of power receiving electrodes, the electric vehicle being supplied with power from the pair of power transmitting electrodes by electric field coupling with the pair of power receiving electrodes while traveling on the travel path; A driving power supply system having the same.

2. The in-motion power supply system according to claim 1, The in-motion power supply device further a high frequency oscillator that outputs a high frequency reference signal; a first power amplifier that receives the high-frequency reference signal and outputs a first applied high-frequency signal from the high-frequency signals to be applied to one ends of the pair of power transmitting electrodes; a first directional coupler that emits a first proportional wave that is proportional to a first reflected high frequency wave that travels from the one ends of the pair of power transmitting electrodes toward the first power amplifier; a second directional coupler that emits a second proportional wave that is proportional to the second reflected high frequency wave that travels from the other end of the pair of power transmitting electrodes toward the second power amplifier; a phase difference detector that detects a phase difference between the first proportional wave and the second proportional wave and outputs a phase difference signal corresponding thereto; a variable phase shifter that receives the high-frequency reference signal and the phase difference signal and outputs a high-frequency phase-shifted reference signal having the same frequency as the high-frequency reference signal but a phase that is changed in accordance with the phase difference signal; a second power amplifier that receives the high-frequency phase-shifted reference signal and outputs a second applied high-frequency signal, which is one of the high-frequency signals, to be applied to the other end of the pair of power transmitting electrodes.

3. The in-motion power supply system according to claim 2, The in-motion power supply device further an amplitude difference detector that detects an amplitude difference between a third proportional wave proportional to the first applied high frequency wave and a fourth proportional wave proportional to the second applied high frequency wave, and outputs an amplitude difference signal corresponding thereto; A moving-vehicle power supply system, wherein the gain of the second power amplifier and / or the first power amplifier is controlled in response to the amplitude difference signal.

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