JP2019017167A - Power transmission system and non-contact power supply system - Google Patents

Abstract

To equalize the magnitude of current flowing in individual power transmission devices while reducing a length of a whole transmission line that is laid between a high frequency power source and each power transmission device.SOLUTION: A power transmission system comprise: a high frequency power supply 21 that outputs a high frequency power; a transmission unit 22 that includes an LC circuit 222 including a coil and a capacitor and a transmission line 221; and a power transmission coil unit 23 that transmits the high frequency power transmitted through the transmission unit 22 to a power reception side. The transmission unit 22 is positioned between the high frequency power supply and one power transmission coil unit and between the power transmission coil units so that the high frequency power supply 21 and a whole power transmission coil unit 23 are serially connected, and is connected to at least one of the high frequency power supply and the power transmission coil unit. With respect to a phase of current when the high frequency power is input to itself, the transmission unit 22 transmits high frequency power so that the phase of the current when outputting the high frequency power is an integer multiple of 180 degrees.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission system and a non-contact power supply system.

  In recent years, development of a non-contact power feeding system that supplies power from a power transmitting device to a power receiving device in a contactless manner has been advanced. Patent Document 1 below discloses a non-contact power feeding system that transmits power generated by a single high-frequency power source to a plurality of power transmission devices via transmission lines, and supplies power from each power transmission device to the power receiving device in a contactless manner. Is disclosed.

  The contactless power feeding system described in Patent Document 1 is to solve the problem that the current output from the power receiving device changes every time the impedance of a load such as a battery changes due to the influence of the reactance component of the transmission line. A reactance element for canceling the reactance component of the transmission line is provided between the transmission line and the power transmission device. This reactance element is set so that the reactance component of the transmission line is equal in magnitude and opposite in polarity.

JP, 2006-192856, A

  In the non-contact power feeding system described in Patent Document 1, it is necessary to lay transmission lines according to the number of power transmission devices. Therefore, for example, when each power transmission device is installed along a production line of a factory, transmission lines are respectively laid between the scattered power transmission devices and one high-frequency power source. In this case, the length of the transmission line required in the entire non-contact power feeding system is increased, and the length of the transmission line connected to each power transmission device is different.

  Here, when the power output from the high frequency power supply is high frequency power such as 6.78 MHz or 13.35 MHz, for example, if the length of the transmission line connecting the high frequency power supply and each power transmission device is different, each power transmission device The magnitudes of the currents flowing through are different. In this case, even if the plurality of power transmission devices and the plurality of power reception devices constituting the non-contact power supply system described in Patent Document 1 are arranged in the same configuration, the magnitude of the current output from each power reception device is It will be different.

  Therefore, under the situation where the magnitude of the current flowing through each power transmission device is different, even if the same load is connected to each power receiving device, the current supplied to each load will be different. In some cases, there will be a difference in battery charging time.

  Therefore, the present invention provides a power transmission system and a non-contact power feeding system capable of aligning the magnitude of current flowing through each power transmission device while shortening the entire length of the transmission line laid between the high-frequency power source and each power transmission device. The purpose is to provide.

  A power transmission system according to an aspect of the present invention includes a high-frequency power source that outputs high-frequency power of a predetermined frequency, an LC circuit that includes a coil and a capacitor, a plurality of transmission units that include a transmission line connected to the LC circuit, and a transmission unit. A plurality of power transmission devices that transmit high-frequency power transmitted to the power receiving side, and the transmission unit includes a high-frequency power source and one power transmission device so that the high-frequency power source and all power transmission devices are connected in series. When high-frequency power is output based on the phase of the current when the high-frequency power is input to the own transmission unit. The high frequency power is transmitted so that the phase of the current becomes an integer multiple of 180 degrees.

  According to this aspect, the transmission unit is disposed between the high-frequency power source and one power transmission device and between each power transmission device so that the high-frequency power source and all the power transmission devices are connected in series. It can be connected to at least one of the power transmission devices, and the phase of the current when outputting the high frequency power is an integral multiple of 180 degrees with reference to the phase of the current when the high frequency power is input to the own transmission unit. Thus, it becomes possible to transmit high frequency power. This makes it possible to shorten the length of the entire transmission line laid between the high-frequency power supply and each power transmission device, and to make the current flowing through each power transmission device the same size. Become.

  In the above aspect, the inductance of the coil and the capacitance of the capacitor may be set based on the length of the transmission line.

  According to this aspect, by setting the inductance of the coil and the capacitance of the capacitor according to the length of the transmission line, the phase of the current when outputting high-frequency power from the transmission unit is compared with the phase of the current at the time of input. Since it can be adjusted to be an integral multiple of 180 degrees, the length of the transmission line can be further shortened.

  In the above aspect, the length of at least one transmission line may be different from the length of other transmission lines.

  According to this aspect, the length of the transmission line can be arbitrarily changed according to the installation location of the power transmission device.

  In the above aspect, the LC circuit may be either a π-type circuit having a CLC configuration or a T-type circuit having an LCL configuration.

  According to this aspect, any one of the π-type circuit having the CLC configuration and the T-type circuit having the LCL configuration can be appropriately employed as the LC circuit.

  A contactless power supply system according to another aspect of the present invention is a contactless power supply system that supplies power from a power transmission system to a power reception system in a contactless manner, the power transmission system including a high frequency power source that outputs high frequency power of a predetermined frequency; A plurality of transmission units including an LC circuit including a coil and a capacitor and a transmission line connected to the LC circuit, and a plurality of power transmission devices that transmit high-frequency power transmitted through the transmission unit to the power receiving side, The transmission unit is arranged between the high-frequency power source and one power transmission device and between each power transmission device so that the high-frequency power source and all the power transmission devices are connected in series. The level of current when high-frequency power is output, based on the phase of the current when high-frequency power is input to the connected transmission unit. So they become an integral multiple of 180 degrees, and transmitting a high frequency power, the power receiving system includes a plurality of power receiving apparatus receiving the high-frequency power.

  According to this aspect, the transmission unit is disposed between the high-frequency power source and one power transmission device and between each power transmission device so that the high-frequency power source and all the power transmission devices are connected in series. It can be connected to at least one of the power transmission devices, and the phase of the current when outputting the high frequency power is an integral multiple of 180 degrees with reference to the phase of the current when the high frequency power is input to the own transmission unit. Thus, it becomes possible to transmit high frequency power. This makes it possible to shorten the length of the entire transmission line laid between the high-frequency power supply and each power transmission device, and to make the current flowing through each power transmission device the same size. Become.

  In the above aspect, the inductance of the coil and the capacitance of the capacitor may be set based on the length of the transmission line.

  According to this aspect, by setting the inductance of the coil and the capacitance of the capacitor according to the length of the transmission line, the phase of the current when outputting high-frequency power from the transmission unit is compared with the phase of the current at the time of input. Since it can be adjusted to be an integral multiple of 180 degrees, the length of the transmission line can be further shortened.

  In the above aspect, the power transmission device includes a series resonance circuit including a power transmission coil and a resonance capacitor, the power reception device includes a series resonance circuit including a power reception coil and a resonance capacitor, and the power reception system is output from the power reception device. A voltage-current conversion circuit that converts a voltage into a current may be further provided.

  According to this aspect, since the contactless power feeding system can be a primary series secondary series capacitor system, when the current of the power transmission coil is a constant current, the voltage output from the power receiving device is a constant voltage, It becomes possible to make the current output from the voltage-current converter circuit a constant current.

  In the above aspect, the power receiving system may include a switch that short-circuits the output of the voltage-current conversion circuit.

  According to this aspect, the power supply to the subsequent stage side of the voltage / current conversion circuit corresponding to the shorted switch is stopped, and the power supply to the subsequent stage side of the voltage / current conversion circuit corresponding to the other switch is maintained as it is. Is possible.

  In the above aspect, the power transmission device may include a series resonance circuit including a power transmission coil and a resonance capacitor, and the power reception device may include a parallel resonance circuit including a power reception coil and a resonance capacitor.

  According to this aspect, since the non-contact power feeding system can be a primary series / secondary parallel capacitor system, when the current of the power transmission coil is a constant current, the current output from the power receiving device is a constant current. It becomes possible.

  In the above aspect, the power receiving system may include a switch that short-circuits the output of the power receiving device.

  According to this aspect, it is possible to stop the power supply to the rear stage side of the power receiving apparatus corresponding to the short-circuited switch and to maintain the power supply to the rear stage side of the power receiving apparatus corresponding to the other switch as it is. .

  According to the present invention, a power transmission system and a non-contact power feeding system capable of aligning the magnitude of current flowing through each power transmission device while shortening the length of the entire transmission line laid between the high-frequency power source and each power transmission device Can be provided.

It is a figure which illustrates the circuit structure of the non-contact electric power feeding system in 1st Embodiment. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric supply system shown in FIG. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric supply system shown in FIG. It is a figure which illustrates the circuit structure of the non-contact electric power feeding system in 2nd Embodiment. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric power feeding system shown in FIG. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric power feeding system shown in FIG. It is a figure which illustrates the circuit structure of the non-contact electric power feeding system in 3rd Embodiment. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric supply system shown in FIG. It is a graph which illustrates the simulation result of the electronic circuit in the non-contact electric supply system shown in FIG.

  A preferred embodiment of the present invention will be described with reference to the accompanying drawings. The non-contact power feeding system in each embodiment is a system that transmits high-frequency power of several MHz to several hundreds of MHz in a non-contact manner from the power transmission side to the power receiving side by a magnetic field resonance method.

[First Embodiment]
FIG. 1 is a diagram illustrating a circuit configuration of a non-contact power feeding system in the first embodiment. As shown in FIG. 1, the non-contact power feeding system 1 includes a power transmission system 2 and a power receiving system 3.

  The power transmission system 2 includes a high-frequency power source 21, a plurality of transmission units 22a, 22b, and 22c, and a plurality of power transmission coil units (power transmission devices) 23a, 23b, and 23c. Note that the transmission units 22a, 22b, and 22c and the power transmission coil units 23a, 23b, and 23c will be referred to as the transmission unit 22 and the power transmission coil unit 23, respectively, unless they need to be distinguished from each other.

  The high frequency power supply 21 outputs high frequency power having a predetermined frequency (for example, a high frequency of 6.78 MHz or higher). The high frequency power output from the high frequency power supply 21 is controlled by a power transmission side control unit (not shown). The high frequency power source 21 can be applied to both a voltage source and a current source.

  The power transmission side control unit includes, for example, a microcomputer including a ROM, a RAM, a CPU, an FPGA (field-programmable gate array), and the like. The power transmission side control unit outputs, for example, an output control signal for controlling the output voltage of the DC-DC converter to the high frequency power source 21 to control the high frequency power output from the high frequency power source 21.

  The transmission unit 22 includes a circuit in which a transmission line 221 and an LC circuit 222 are connected in series, and is arranged so that the high-frequency power source 21 and all the power transmission coil units 23 are connected in series. Specifically, the transmission unit 22a is disposed between the high frequency power supply 21 and the power transmission coil unit 23a, and is connected in series with both the high frequency power supply 21 and the power transmission coil unit 23a. The transmission unit 22b is disposed between the power transmission coil unit 23a and the power transmission coil unit 23b, and is connected in series with both the power transmission coil units 23a and 23b. The transmission unit 22c is disposed between the power transmission coil unit 23b and the power transmission coil unit 23c, and is connected in series with both the power transmission coil units 23b and 23c.

  In this way, by connecting the high-frequency power source 21 and all the power transmission coil units 23 in series via the transmission unit 22, transmission lines are respectively laid between one high-frequency power source and the scattered power transmission coil units. Compared to the case, the length of the entire transmission line laid between the high-frequency power source and each power transmission coil unit can be shortened. Moreover, it becomes possible to make the magnitude | size of the electric current which flows into each power transmission coil unit 23 the same magnitude | size by connecting the high frequency power supply 21 and all the power transmission coil units 23 in series.

  The transmission line 221 is, for example, a coaxial cable having a characteristic impedance of 50 [Ω]. The transmission line 221 is not limited to this, and may be, for example, a 75 [Ω] coaxial cable, a parallel two-wire feeder, or a strip line.

  The LC circuit 222 is, for example, a π-type circuit having a CLC configuration using one coil 2221 and two capacitors 2222 and 2223.

  In FIG. 1, the transmission line 221 is disposed on the upstream side of the LC circuit 222, but the transmission line 221 may be disposed on the downstream side of the LC circuit 222.

  The transmission unit 22 configured as described above uses the phase of current when high frequency power is input to the own transmission unit 22 as a reference (0 degree), and the phase of current when high frequency power is output is 180 degrees. As such, high-frequency power is transmitted. That is, the transmission unit 22 transmits the high frequency power so that the phase of the current when output is 180 degrees with reference to the phase of the current input to the own transmission unit 22.

  Here, when the length of the transmission line 221 is set to a length equivalent to ½ wavelength of the frequency output from the high frequency power supply 21, the phase of the current when the high frequency power is input to the transmission line 221 is used as a reference. Thus, the phase of the current output from the transmission line 221 can be 180 degrees. In this case, high-frequency power can be transmitted without using the LC circuit 222.

  However, when the frequency of the high frequency power supply 21 is set to 13.56 MHz, for example, the wavelength of the high frequency is about 22 m, and the half wavelength is about 11 m. In this case, when the transmission unit 22 is configured by only the transmission line 221, the length of each transmission line 221 is about 11 m, which is the same length as the half wavelength at the shortest. At this time, when the power transmission coil unit 23 connected to the high frequency power source 21 is installed at a distance of less than 11 m from the high frequency power source 21, the transmission line 221 that is longer than necessary is laid.

  The non-contact power feeding system 1 in the present embodiment enables the length of the transmission line 221 to be less than 11 m by including the LC circuit 222 in the transmission unit 22. The LC circuit 222 supplements a length that is less than the half wavelength that is insufficient by shortening the length of the transmission line 221.

  For example, when the length of the transmission line 221 is set to a length equivalent to a quarter wavelength (about 5.5 m), the transmission line 221 outputs compared to the phase of the current at the time of input (assuming 0 degree). The phase of the current at the time is 90 degrees. In this case, the remaining 90 degrees (1/4 wavelength) is supplemented by the LC circuit 222, and the entire transmission unit 22 is adjusted to 180 degrees. The adjustment by the LC circuit 222 is performed as follows, for example.

The inductance (ω ₀ L ₁ ) of the coil 2221 of the LC circuit 222 and the capacitance (1 / ω ₀ C ₁ ) of the capacitors 2222 and 2223 are obtained by the following equations (1) and (2), and these are respectively calculated by the LC circuit 222. Adjust by setting to. Here, Z _o in the equations (1) and (2) is the value of the characteristic impedance of the transmission line 221, β is 2π / λ (λ: wavelength), and x is the length of the transmission line 221. (Less than ½ wavelength), ω ₀ is the angular frequency (2πf) of the output of the high-frequency power source 21.

ω ₀ L ₁ = Z _o · tan (β (0.5−x) / 2) (1)
1 / ω ₀ C ₁ = Z _o /sin(β(0.5−x)) (2)

The configuration of the LC circuit 222 is not limited to the above-described π-type circuit having the CLC configuration. For example, the configuration of the LC circuit 222 may be an L-CL configuration T-type circuit using two coils and one capacitor. In this case, the capacitance (1 / ω ₀ C ₂ ) of the capacitor and the inductance (ω ₀ L ₂ ) of the coil can be obtained by the following equations (3) and (4). Here, Z _o in the equations (3) and (4) is the value of the characteristic impedance of the transmission line 221, β is 2π / λ (λ: wavelength), and x is the length of the transmission line 221. (Less than ½ wavelength), ω ₀ is the angular frequency (2πf) of the output of the high-frequency power source 21.

1 / ω ₀ C ₂ = Z _o · sin (β (0.5−x)) / (1-cos (β (0.5−x))) (3)
ω ₀ L ₂ = Z _o · sin (β (0.5−x)) Equation (4)

  In this way, by configuring the transmission unit 22 including the transmission line 221 and the LC circuit 222, the length of the transmission line 221 is made shorter than the length required when connecting only by the transmission line 221. Can do. That is, the length of the entire transmission line laid between the high-frequency power source and each power transmission coil unit can be further shortened.

  The power transmission coil unit 23 wirelessly transmits high-frequency power transmitted through the transmission unit 22 to the power receiving system 3 side. The power transmission coil unit 23 is also referred to as, for example, an inductor (hereinafter also referred to as “power transmission coil”) 231 formed of a solenoid coil having a plurality of turns, and a capacitor (hereinafter referred to as “resonance capacitor”) connected in series to the inductor 231. ) 232 and a series resonance circuit. Note that a stray capacitance generated in the inductor 231 may be used instead of the capacitor 232.

The series resonance frequency (= 1 / {2π · √ (L ₃ · C ₃ )}) (L ₃ : self-inductance of inductor 231, C ₃ : capacitance of capacitor 232) of the series resonance circuit in power transmission coil unit 23 is a high frequency. The frequency is adjusted to the frequency of the high frequency power output from the power supply 21 (hereinafter also referred to as “power supply frequency”).

  The power receiving system 3 includes power receiving coil units (power receiving devices) 31a, 31b, and 31c, voltage / current conversion circuits 32a, 32b, and 32c, switches 33a, 33b, and 33c, rectifier circuits 34a, 34b, and 34c, and a power receiving device (not shown). A side control unit and capacitors 35a, 35b, and 35c. The power receiving coil units 31a, 31b, 31c, the voltage / current conversion circuits 32a, 32b, 32c, the switches 33a, 33b, 33c, the rectifier circuits 34a, 34b, 34c, and the capacitors 35a, 35b, 35c are specifically distinguished below. When there is no need to do this, they are described as a power receiving coil unit 31, a voltage / current conversion circuit 32, a switch 33, a rectifier circuit 34, and a capacitor 35, respectively.

  The power receiving coil unit 31 magnetically couples with the power transmitting coil unit 23 to receive high frequency power. The power receiving coil unit 31 has the same configuration as that of the power transmitting coil unit 23, and is connected in series to, for example, an inductor (hereinafter also referred to as “power receiving coil”) 311 including a solenoid coil having a plurality of turns, and the inductor 311. And a series resonance circuit with a capacitor (hereinafter also referred to as “resonance capacitor”) 312. Note that a stray capacitance generated in the inductor 311 may be used instead of the capacitor 312.

The series resonance frequency (= 1 / {2π · √ (L ₄ · C ₄ )}) (L ₄ : self-inductance of inductor 311, C ₄ : capacitance of capacitor 312) of the power supply coil unit 31 is determined by the power supply The frequency is adjusted.

Since the non-contact power feeding system 1 in the first embodiment is an SS (primary series / secondary series capacitor) system using magnetic field resonance, the current I ₁ of the power transmission coil 231 is a constant current (constant), and the power transmission coil 231. When the mutual inductance M between the power receiving coil 311 does not vary, the voltage V ₂ output from the power receiving coil unit 31 becomes a constant voltage (constant). The relationship between the current I ₁ and the voltage V ₂ can be expressed as the following formula (5). Here, ω ₀ in equation (5) is the angular frequency (2πf) of the output of the high-frequency power source 21.

V ₂ = ω ₀ MI ₁ Formula (5)

  The voltage-current conversion circuit 32 converts the voltage output from the power receiving coil unit 31 into a current. In the voltage-current conversion circuit 32, when the magnitude of the input voltage is constant, the magnitude of the output current is constant.

The voltage-current conversion circuit 32 is, for example, a λ / 4 type LPF circuit having an LCL T-type configuration using two coils 321 and 322 and one capacitor 323. The relationship between the inductance L ₅ of the coils 321 and 322 of the voltage-current conversion circuit 32 and the capacitance C _{5 of the} capacitor 323 can be expressed as the following equation (6). Here, ω ₀ in equation (6) is the angular frequency (2πf) of the output of the high frequency power supply 21, and Z _o is the impedance of the voltage-current conversion circuit 32.

ω ₀ L ₅ = 1 / ω ₀ C ₅ = Z _o (6)

  The configuration of the voltage-current conversion circuit 32 is not limited to the λ / 4 LPF circuit having the L-CL T-type configuration described above. For example, the configuration of the voltage-current conversion circuit 32 is a λ / 4 type LPF circuit with a CLC π-type configuration using two capacitors and one coil, or the L-C-L T type described above. A λ / 4 type HPF circuit having a configuration in which C and L included in the π-type configuration of C-L-C are interchanged may be used.

  The switch 33 has, for example, a circuit configuration in which MOSFETs are connected in anti-series and short-circuits the output of the voltage / current conversion circuit 32. The switch 33 is opened when current is supplied to the subsequent stage of the voltage / current conversion circuit 32, and the switch 33 is short-circuited when current is not supplied to the subsequent stage of the voltage / current conversion circuit 32.

  The rectifying circuit 34 rectifies the high frequency power output from the power receiving coil unit 31 and supplies DC power to the capacitor 35. The rectifier circuit 34 is configured by, for example, a bridge circuit in which four rectifier elements are bridge-connected. For example, Schottky barrier diodes are used as the four rectifying elements.

  The power receiving side control unit is configured by a microcomputer, FPGA, or the like that includes a ROM, a RAM, a CPU, and the like. The power receiving side control unit outputs a control signal to each component of the power receiving system 3 to control the entire power receiving system 3.

  The capacitor 35 may be an electrochemical capacitor or a secondary battery. As an electrochemical capacitor, for example, an electric double layer capacitor, a hybrid capacitor represented by a lithium ion capacitor, a redox capacitor, or the like can be used. As a secondary battery, for example, a nickel metal hydride battery, a lead storage battery, a lithium ion battery, sodium A sulfur battery or the like can be used.

  Next, referring to FIG. 2, in the non-contact power feeding system 1 of the first embodiment, the magnitude of the current flowing through each power transmission coil unit 23 is the same, and the magnitude of the current charged in each capacitor 35 is the same. Explain what will become.

  Illustratively, the settings, conditions, etc. of each component when simulating the operation of the non-contact power feeding system 1 are determined as follows. The output of the high frequency power supply 21 is set to a high frequency power of 13.56 MHz. Circuit constants of three power transmission coil units 23a, 23b, 23c, circuit constants of three power receiving coil units 31a, 31b, 31c, circuit constants of three voltage-current conversion circuits 32a, 32b, 32c, and three rectifier circuits 34a, The circuit constants 34b and 34c are set to the same circuit constant. The capacitances of the three capacitors 35a, 35b, and 35c are set to the same capacitance, and the initial charging voltages of the three capacitors 35a, 35b, and 35c are set to different voltages. The lengths of the transmission lines 221 of the three transmission units 22a, 22b, and 22c are set to different lengths. The coupling coefficient between the three power transmission coils 231 and the three power reception coils 311 is set to the same coupling coefficient. All the three switches 33a, 33b, and 33c are opened. Micro-Cap is used as an electronic circuit simulator.

  FIG. 2A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21. The drain current DI in FIG. 2A shows a 10 times larger current value in the graph.

  2B is a graph showing the charging current CIa of the capacitor 35a, FIG. 2C is a graph showing the charging current CIb of the capacitor 35b, and FIG. 2D is the charging current of the capacitor 35c. It is a graph showing CIc.

  As shown in FIGS. 2B, 2C, and 2D, the charging currents CIa, CIb, and CIc of the three capacitors 35a, 35b, and 35c have the same magnitude.

  2E shows the output current II of the high-frequency power source 21, the current LIb flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current LIa flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. It is a graph showing the electric current LIc which flows into.

  As shown in FIG. 2E, the magnitudes of the currents LIa, LIb, and LIc flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the magnitudes of the currents LIa, LIb, and LIc flowing through the three power transmission coil units 23a, 23b, and 23c are the same.

  Thus, according to the non-contact electric power feeding system 1 in 1st Embodiment, the magnitude | size of the electric current which flows into each power transmission coil unit 23 is made the same magnitude | size, and the magnitude | size of the electric current charged to each capacitor 35 is the same magnitude | size. Can be.

  Next, referring to FIG. 3, when the switch 33b in the middle power receiving system 3 is short-circuited from the state shown in FIG. 2 described above, the current flowing in each power transmission coil unit 23 and each capacitor 312 are charged. The current will be described.

  FIG. 3A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21. The drain current DI in FIG. 3A shows a 10 times larger current value in the graph.

  3B is a graph showing the charging current CIa of the capacitor 35a, FIG. 3C is a graph showing the charging current CIb of the capacitor 35b, and FIG. 3D is the charging current of the capacitor 35c. It is a graph showing CIc.

  As shown in FIG. 3C, the charging current CIb of the middle stage capacitor 35b in which the switch 33b is short-circuited becomes zero. On the other hand, as shown in FIGS. 3B and 3D, the charging currents CIa and CIc of the remaining two capacitors 35a and 35c are maintained in the same state.

  FIG. 3E shows the output current II of the high-frequency power source 21, the current LIb flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current LIa flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. It is a graph showing the electric current LIc which flows into.

  As shown in FIG. 3E, the magnitudes of the currents LIa, LIb, and LIc flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the currents LIa, LIb, and LIc flowing through the three power transmission coil units 23a, 23b, and 23c are maintained in the same state.

  Thus, according to the non-contact power feeding system 1 in the first embodiment, by short-circuiting the switch 33, only charging of the capacitor 35 corresponding to the short-circuited switch 33 is stopped, and charging to the other capacitors 35 is performed. Can be continued as is.

  As described above, according to the non-contact power feeding system 1 in the first embodiment, the transmission unit 22 is connected to the high frequency power source 21 and one power transmission so that the high frequency power source 21 and all the power transmission coil units 23 are connected in series. It is arranged between the coil unit 23 and between each power transmission coil unit 23 and can be connected to at least one of the high frequency power source 21 and the power transmission coil unit 23, and the phase when the high frequency power is input to the own unit. , The high frequency power can be transmitted so that the phase when the high frequency power is output is 180 degrees.

  Thereby, the length of the entire transmission line laid between the high-frequency power source 21 and each power transmission coil unit 23 can be shortened, and the magnitude of the current flowing through each power transmission coil unit 23 can be made uniform.

[Second Embodiment]
A second embodiment of the present invention will be described. The non-contact power feeding system 1s in the second embodiment shown in FIG. 4 differs from the above-described non-contact power feeding system 1 in the first embodiment shown in FIG. 1 in that the configuration of the power receiving coil unit is different, and the first implementation. The voltage-current conversion circuit 32 of the embodiment is omitted. About another structure, it is the same as that of each structure of the non-contact electric power feeding system in 1st Embodiment (it is good also as employ | adopting any structure about another different part). Therefore, the same reference numerals are given to the respective components, and the description thereof is omitted. In the following, differences from the first embodiment will be mainly described.

  As shown in FIG. 4, the receiving coil units 31sa, 31sb, 31sc of the non-contact power feeding system 1s are, for example, a parallel arrangement of an inductor 311 composed of a solenoid coil having a plurality of turns and a capacitor 312s connected in parallel to the inductor 311. It consists of a resonant circuit.

  Note that the power receiving coil units 31sa, 31sb, and 31sc will be referred to as the power receiving coil unit 31s when it is not necessary to distinguish them in the following description. Further, a stray capacitance generated in the inductor 311 may be used instead of the capacitor 312s.

Since the non-contact power feeding system 1 s in the second embodiment is an SP (primary series / secondary parallel capacitor) system using magnetic field resonance, the current I ₁ of the power transmission coil 231 is a constant current (constant), and the power transmission coil 231. When the mutual inductance M between the power receiving coil 311 does not change, the current I ₂ output from the power receiving coil unit 31s becomes a constant current (constant). The relationship between the current I ₁ and the current I ₂ can be expressed as the following formula (7). Here, a is n ₁ / n ₂ (n ₁ : the number of turns of the power receiving coil 231, n ₂ : the number of turns of the power receiving coil 311), and L ₂ is the self-inductance of the power receiving coil 311.

I ₂ = {M / (a · L ₂ )} I ₁ (7)

  The switch 33 in the second embodiment shorts the output of the power receiving coil unit 31s. The switch 33 is opened when current is supplied to the downstream side of the power receiving coil unit 31s, and the switch 33 is short-circuited when current is not passed through the downstream side of the power receiving coil unit 31s.

  Next, referring to FIG. 5, in the non-contact power feeding system 1 s according to the second embodiment, the magnitudes of currents flowing through the power transmission coil units 23 are the same, and the magnitudes of currents output from the power receiving coil units 31 s. Will be described, and the magnitude of the current charged in each capacitor 35 will be the same.

  Illustratively, the settings, conditions, and the like of each component when simulating the operation of the non-contact power feeding system 1s are determined as follows. The output of the high frequency power supply 21 is set to a high frequency power of 13.56 MHz. The circuit constants of the three power transmission coil units 23a, 23b, and 23c, the circuit constants of the three power reception coil units 31sa, 31sb, and 31sc, and the circuit constants of the three rectifier circuits 34a, 34b, and 34c are set to the same circuit constant. . The capacitances of the three capacitors 35a, 35b, and 35c are set to the same capacitance, and the initial charging voltages of the three capacitors 35a, 35b, and 35c are set to different voltages. The lengths of the transmission lines 221 of the three transmission units 22a, 22b, and 22c are set to different lengths. The coupling coefficient between the three power transmission coils 231 and the three power reception coils 311 is set to the same coupling coefficient. All the three switches 33a, 33b, and 33c are opened. LTspice is used as an electronic circuit simulator.

  FIG. 5A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21.

  FIG. 5B shows the output current II of the high-frequency power source 21, the current L1Ib flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current L1Ia flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. It is a graph showing the electric current L1Ic which flows into.

  As shown in FIG. 5B, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same.

  FIG. 5C is a graph showing the output current L2Ib of the power receiving coil unit 31sb, the output current L2Ia of the power receiving coil unit 31sa, and the output current L2Ic of the power receiving coil unit 31sc.

  As shown in FIG. 5C, the magnitudes of the output currents L2Ia, L2Ib, and L2Ic of the three power receiving coil units 31sa, 31sb, and 31sc are the same.

  FIG. 5D is a graph showing the charging current CIa of the capacitor 35a, the charging current CIb of the capacitor 35b, and the charging current CIc of the capacitor 35c.

  As shown in FIG. 5D, the charging currents CIa, CIb, CIc of the three capacitors 35a, 35b, 35c have the same magnitude.

  Thus, according to the non-contact electric power feeding system 1s in 2nd Embodiment, the magnitude | size of the electric current which flows into each power transmission coil unit 23 is made the same magnitude | size, and the magnitude | size of the electric current output from each receiving coil unit 31s is the same. The magnitude of the current charged in each capacitor 35 can be made the same.

  Next, referring to FIG. 6, when the switch 33b in the middle power receiving system 3 is short-circuited from the state shown in FIG. 4 described above, the current flowing through each power transmitting coil unit 23 and the output from each power receiving coil unit 31s. A description will be given of how the current to be charged and the current charged to each capacitor 312 become.

  FIG. 6A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21.

  6B shows the output current II of the high-frequency power source 21, the current L1Ib flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current L1Ia flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. It is a graph showing the electric current L1Ic which flows into.

  As shown in FIG. 6B, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are maintained in the same state.

  FIG. 6C is a graph showing the output current L2Ib of the power receiving coil unit 31sb, the output current L2Ia of the power receiving coil unit 31sa, and the output current L2Ic of the power receiving coil unit 31sc.

  As shown in FIG. 6C, the output current L2Ib of the middle power receiving coil unit 31sb in which the switch 33b is short-circuited becomes zero. On the other hand, the output currents L2Ia and L2Ic of the remaining two power receiving coil units 31sa and 31sc are maintained in the same state.

  FIG. 6D is a graph showing the charging current CIa of the capacitor 35a, the charging current CIc of the capacitor 35c, and the charging current CIb of the capacitor 35b.

  As shown in FIG. 6D, the charging current CIb of the middle-stage capacitor 35b in which the switch 33b is short-circuited becomes zero. On the other hand, the charging currents CIa and CIc of the remaining two capacitors 35a and 35c are maintained in the same state.

  Thus, according to the non-contact power feeding system 1s in the second embodiment, by short-circuiting the switch 33, only charging of the capacitor 35 corresponding to the short-circuited switch 33 is stopped, and charging to the other capacitors 35 is performed. Can be continued as is.

[Third Embodiment]
A third embodiment of the present invention will be described. The non-contact power feeding system 1t in the third embodiment shown in FIG. 7 is different from the above-described non-contact power feeding system 1s in the second embodiment shown in FIG. 4 in that the configuration of the LC circuit of the transmission unit 22 is different. . About another structure, it is the same as that of each structure of the non-contact electric power feeding system in 2nd Embodiment. Therefore, the same reference numerals are given to the respective components, and the description thereof is omitted. In the following, differences from the second embodiment will be mainly described.

  As shown in FIG. 7, the LC circuit 222t of the transmission unit 22 in the contactless power feeding system 1t is, for example, an L-C-L T-type circuit using two coils 2224 and 2225 and one capacitor 2226. .

  Next, referring to FIG. 8, in the non-contact power feeding system 1t according to the third embodiment, the magnitudes of the currents flowing through the power transmission coil units 23 are the same, and the magnitudes of the currents output from the power receiving coil units 31s. Will be described, and the magnitude of the current charged in each capacitor 35 will be the same.

  Here, since the setting, conditions, etc. of each component when simulating the operation of the non-contact power feeding system 1t are the same as those of the non-contact power feeding system 1s in the second embodiment described above, the description thereof is omitted.

  FIG. 8A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21.

  FIG. 8B shows the output current II of the high-frequency power source 21, the current L1Ib flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current L1Ia flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. 6 is a graph showing a current L1Ic flowing through

  As shown in FIG. 8B, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same.

  FIG. 8C is a graph showing the output current L2Ib of the power receiving coil unit 31sb, the output current L2Ia of the power receiving coil unit 31sa, and the output current L2Ic of the power receiving coil unit 31sc.

  As shown in FIG. 8C, the magnitudes of the output currents L2Ia, L2Ib, L2Ic of the three power receiving coil units 31sa, 31sb, 31sc are the same.

  FIG. 8D is a graph showing the charging current CIa of the capacitor 35a, the charging current CIb of the capacitor 35b, and the charging current CIc of the capacitor 35c.

  As shown in FIG. 8D, the charging currents CIa, CIb, CIc of the three capacitors 35a, 35b, 35c have the same magnitude.

  Thus, according to the non-contact electric power feeding system 1t in 3rd Embodiment, the magnitude | size of the electric current which flows into each power transmission coil unit 23 is made the same magnitude | size, and the magnitude | size of the electric current output from each receiving coil unit 31s is the same. The magnitude of the current charged in each capacitor 35 can be made the same.

  Next, referring to FIG. 9, when the switch 33b in the middle power receiving system 3 is short-circuited from the state shown in FIG. 7 described above, the current flowing through each power transmitting coil unit 23 and the output from each power receiving coil unit 31s are shown. A description will be given of how the current to be charged and the current charged to each capacitor 312 become.

  FIG. 9A is a graph showing the drain voltage DV and the drain current DI of the FET included in the high-frequency power source 21.

  FIG. 9B shows the output current II of the high-frequency power source 21, the current L1Ib flowing through the power transmission coil 231 of the power transmission coil unit 23b, the current L1Ia flowing through the power transmission coil 231 of the power transmission coil unit 23a, and the power transmission coil 231 of the power transmission coil unit 23c. 6 is a graph showing a current L1Ic flowing through

  As shown in FIG. 9B, the magnitudes of the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are the same as the magnitude of the output current II of the high-frequency power source 21. That is, the currents L1Ia, L1Ib, and L1Ic flowing through the three power transmission coil units 23a, 23b, and 23c are maintained in the same state.

  FIG. 9C is a graph showing the output current L2Ib of the power receiving coil unit 31sb, the output current L2Ia of the power receiving coil unit 31sa, and the output current L2Ic of the power receiving coil unit 31sc.

  As shown in FIG. 9C, the output current L2Ib of the middle receiving coil unit 31sb in which the switch 33b is short-circuited becomes zero. On the other hand, the output currents L2Ia and L2Ic of the remaining two power receiving coil units 31sa and 31sc are maintained in the same state.

  FIG. 9D is a graph showing the charging current CIa of the capacitor 35a, the charging current CIc of the capacitor 35c, and the charging current CIb of the capacitor 35b.

  As shown in FIG. 9D, the charging current CIb of the middle stage capacitor 35b in which the switch 33b is short-circuited becomes zero. On the other hand, the charging currents CIa and CIc of the remaining two capacitors 35a and 35c are maintained in the same state.

  Thus, according to the non-contact power feeding system 1t in the third embodiment, by short-circuiting the switch 33, only charging of the capacitor 35 corresponding to the short-circuited switch 33 is stopped, and charging to the other capacitors 35 is performed. Can be continued as is.

[Modification]
Each embodiment described above is for facilitating understanding of the present invention, and is not intended to limit the present invention. Each element provided in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. In addition, the structures shown in different embodiments can be partially replaced or combined.

  For example, in each of the embodiments described above, the case where the length of the transmission line 221 constituting the transmission unit 22 is shorter than ½ wavelength of the frequency output from the high-frequency power source 21 has been described. The present invention can also be applied when the length of is longer than ½ wavelength. Specifically, when the length of the transmission line 221 is longer than ½ wavelength, the transmission unit 22 uses the phase of the current when the high frequency power is input to the own transmission unit 22 as a reference, and the high frequency power The high frequency power may be transmitted so that the phase of the current when the signal is output is an integral multiple of 180 degrees.

  Thereby, when the power transmission coil unit 23 connected to the high frequency power supply 21 is far away from the high frequency power supply 21, transmission is performed using the transmission line 221 longer than ½ wavelength of the frequency output from the high frequency power supply 21. The unit 22 can be configured.

  For example, when the length of the transmission line 221 is set to a length (about 16.5 m) of ¾ wavelength of the frequency (for example, 13.56 MHz) output from the high-frequency power source 21, the transmission line 221 is input to the transmission line 221. Based on the phase of the current, the phase of the current when output is 270 degrees. In this case, the transmission unit 22 transmits the high frequency power so that the phase of the current when output is 360 degrees (twice 180 degrees) with the phase of the current when input as a reference. In this case, the LC circuit 222 supplements the remaining 90 degrees (1/4 wavelength).

  Similarly, when the length of the transmission line 221 is set to a length (about 27.5 m) of 5/4 wavelength of the frequency (for example, 13.56 MHz) output from the high-frequency power source 21, the transmission line 221 is input to the transmission line 221. With reference to the phase of the current, the phase of the current when output is 450 degrees. In this case, the transmission unit 22 transmits the high frequency power so that the phase of the current when output is 540 degrees (3 times 180 degrees) with reference to the phase of the current when input. In this case, the LC circuit 222 supplements the remaining 90 degrees (1/4 wavelength).

DESCRIPTION OF SYMBOLS 1 ... Non-contact electric power feeding system, 2 ... Power transmission system, 3 ... Power receiving system, 21 ... High frequency power supply, 22 ... Transmission unit, 23 ... Power transmission coil unit, 31 ... Power receiving coil unit, 32 ... Voltage current conversion circuit, 33 ... Switch, 34 ... rectifier circuit, 35 ... capacitor, 221 ... transmission line, 222 ... LC circuit, 231 ... inductor (power transmission coil), 232 ... capacitor (resonance capacitor), 311 ... inductor (power reception coil), 312 ... capacitor (resonance capacitor) , 321, 322 ... coil, 323 ... capacitor, 2221 ... coil, 2222, 2223 ... capacitor, 2224, 2225 ... coil, 2226 ... capacitor

Claims (10)

A high-frequency power source that outputs high-frequency power of a predetermined frequency;
A plurality of transmission units including an LC circuit including a coil and a capacitor and a transmission line connected to the LC circuit;
A plurality of power transmission devices that transmit the high-frequency power transmitted through the transmission unit to a power receiving side;
With
The transmission unit is
The high-frequency power source and all the power transmission devices are connected in series, and are arranged between the high-frequency power source and one power transmission device and between the power transmission devices, respectively. Connected with at least one,
The high frequency power is transmitted so that the phase of the current when the high frequency power is output is an integer multiple of 180 degrees with reference to the phase of the current when the high frequency power is input to the own transmission unit.
Power transmission system. The inductance of the coil and the capacitance of the capacitor are set based on the length of the transmission line,
The power transmission system according to claim 1. The length of at least one of the transmission lines is different from the length of the other transmission lines,
The power transmission system according to claim 2. The LC circuit is either a π-type circuit having a CLC configuration or a T-type circuit having an LCL configuration.
The power transmission system according to claim 2 or 3. A contactless power supply system that supplies power from a power transmission system to a power reception system in a contactless manner,
The power transmission system includes:
A high-frequency power source that outputs high-frequency power of a predetermined frequency;
A plurality of transmission units including an LC circuit including a coil and a capacitor and a transmission line connected to the LC circuit;
A plurality of power transmission devices that transmit the high-frequency power transmitted through the transmission unit to a power receiving side;
With
The transmission unit is
The high-frequency power source and all the power transmission devices are connected in series, and are arranged between the high-frequency power source and one power transmission device and between the power transmission devices, respectively. Connected with at least one,
Based on the phase of the current when the high frequency power is input to the own transmission unit, the high frequency power is transmitted so that the phase of the current when the high frequency power is output is an integral multiple of 180 degrees,
The power receiving system includes a plurality of power receiving devices that receive the high-frequency power.
Contactless power supply system. The inductance of the coil and the capacitance of the capacitor are set based on the length of the transmission line,
The contactless power feeding system according to claim 5. The power transmission device has a series resonant circuit including a power transmission coil and a resonant capacitor,
The power receiving device has a series resonant circuit including a power receiving coil and a resonant capacitor,
The power receiving system further includes a voltage-current conversion circuit that converts a voltage output from the power receiving apparatus into a current.
The contactless power feeding system according to claim 5 or 6. The power receiving system includes a switch for short-circuiting the output of the voltage-current conversion circuit,
The contactless power feeding system according to claim 7. The power transmission device has a series resonant circuit including a power transmission coil and a resonant capacitor,
The power receiving device has a parallel resonant circuit including a power receiving coil and a resonant capacitor.
The contactless power feeding system according to claim 5 or 6. The power receiving system includes a switch that short-circuits the output of the power receiving device,
The contactless power feeding system according to claim 9.