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EP-4005851-B1 - POWER FEEDING SYSTEM DURING TRAVELING

EP4005851B1EP 4005851 B1EP4005851 B1EP 4005851B1EP-4005851-B1

Inventors

  • SUMIYA Hayato
  • TAKAHASHI EISUKE
  • YAMAGUCHI NOBUHISA
  • TAKAHASHI MASAYA

Dates

Publication Date
20260506
Application Date
20200717

Claims (10)

  1. A dynamic wireless power transfer system (500) comprising: a power transmission coil (40) that is provided in a road (105); a power transmission circuit (30) that is configured to supply electric power to the power transmission coil (40); a power reception coil (240f, 240r) that is provided in a vehicle (202); a power reception circuit (230) that is connected to the power reception coil (240f, 240r); and a relay circuit (70), characterized in that the relay circuit (70) is provided in a tire of the vehicle, includes at least two relay coils (71a1, 71a2) that are connected in series and arranged at positions different from each other in a circumferential direction of the tire, and is configured to transfer electric power from the power transmission coil (40) to the power reception coil (240f, 240r) by one (71a1) relay coil of the two relay coils opposing the power transmission coil (40) and the other (71a2) relay coil opposing the power reception coil (240f, 240r), wherein a resonance frequency of the relay circuit (70) is a frequency that is within a fixed range that is centered on an applied frequency of an alternating-current voltage that is applied to the power transmission coil (40).
  2. The dynamic wireless power transfer system (500) according to claim 1, wherein further: the relay circuit (70) includes a resonance capacitor (C2) that is connected in series to the two relay coils; and a capacitance of the resonance capacitor (C2) is a capacitance at which the resonance frequency of the relay circuit (70) is a frequency that is within the fixed range that is centered on the applied frequency, when inductance of the relay circuit (70) is equal to or greater than a magnitude that is prescribed in advance.
  3. The dynamic wireless power transfer system (500) according to claim 2, wherein: the capacitance of the resonance capacitor (C2) is a capacitance at which the resonance frequency of the relay circuit (70) is the applied frequency, when the inductance of the relay circuit (70) is a local maximum.
  4. The dynamic wireless power transfer system (500) according to any one of claims 1 to 3, wherein: the relay circuit (70) is configured by a plurality of relay circuits (70u, 70v, 70w), each of which corresponds to a phase of a plurality of phases that have different phases, and each relay circuit comprises a plurality of relay coils (71a1, 71a2, 71b1,71b2, 71c1,71c2).
  5. The dynamic wireless power transfer system (500) according to any one of claims 1 to 4, further comprising: a control apparatus (50) that is configured to control operations of the power transmission circuit (30), wherein the vehicle includes a front wheel tire (60) and a rear wheel tire (62) as the tire, a relay circuit (70) that is provided in the front wheel tire (60) and a relay circuit (80) that is provided in the rear wheel tire (62) as the relay circuit, and a first power transmission coil (40f) that is configured to transmit electric power to the relay circuit (70) that is provided in the front wheel tire (60) and a second power transmission coil (40r) that is configured transmit electric power to the relay circuit (80) that is provided in the rear wheel tire (62) as the power transmission coil (40), and the control apparatus (50) is configured to adjust a phase of a first voltage that is applied to the first power transmission coil (40f) and a phase of a second voltage that is applied to the second power transmission coil (40r).
  6. The dynamic wireless power transfer system (500) according to claim 5, wherein: the phase of the second voltage is a phase that cancels out a magnetic flux that is generated by the phase of the first voltage.
  7. The dynamic wireless power transfer system (500) according to claim 6, wherein: the control apparatus (50) is configured to control the phase of the first voltage and the phase of the second voltage to be opposite phases.
  8. The dynamic wireless power transfer system (500) according to any one of claims 5 to 7, wherein: the control apparatus (50) is configured to acquire wheelbase information (WB) of the vehicle from the vehicle, and to adjust the phase of the first voltage and the phase of the second voltage.
  9. The dynamic wireless power transfer system (500) according to any one of claims 5 to 8, wherein: the control apparatus (50) is configured to acquires steering angle information and vehicle speed information of the vehicle, and to control magnitudes of the first voltage and the second voltage based on the steering angle information and the vehicle speed information.
  10. The dynamic wireless power transfer system (500) according to any one of claims 5 to 9, wherein: the control apparatus (50) is configured to acquires vehicle speed information and wheelbase information of the vehicle from the vehicle, and to control a timing from when a voltage is applied to the first power transmission coil (40f) until a voltage is applied to the second power transmission coil (40r) based on the vehicle speed information and the wheelbase information of the vehicle.

Description

[Technical Field] The present disclosure relates to a dynamic wireless power transfer system that supplies electric power to a moving body such as a vehicle that is traveling. [Background Art] JP 2016 - 220 353 A (PTL 1) discloses a dynamic wireless power transfer system. In the dynamic wireless power transfer system, electric power is transferred from a power transmission coil that is embedded on a ground side to a power reception coil that is mounted under a floor of a vehicle. In a method in PTL 1, because there is a large distance between the power transmission coil and the power reception coil, increasing power transmission efficiency is difficult. In addition, there is also an issue in that the distance between the power transmission coil and the power reception coil changes depending on the vehicle. KR 101 217 655 B1 discloses wireless power transmission system of a car. A transmitter is installed near a ground and generates a resonant frequency. A receiver is installed between a tire and wheel of a car. A first repeater is arranged on the center of the wheel, and a second repeater is fixed to the body of the car. [Summary of Invention] According to an aspect of the present disclosure, a dynamic wireless power transfer system as defined in claim 1 is provided. As a result of this aspect, because electric power is transferred from the power transmission coil to the power reception coil through the relay coil, a distance between the power transmission coil and the power reception coil need not be considered. An issue in that the distance between the power transmission coil and the power reception coil changes depending on the vehicle also need not be considered. The resonance frequencies of the power transmission coil, the power reception coil, and the relay coil are frequencies within a fixed range that is centered on a frequency that is prescribed in advance. Therefore, transfer efficiency from the power transmission coil to the power reception coil can be improved. Advantageous developments are defined in the dependent claims. [Brief Description of Drawings] The above-described object, other objects, characteristics, and advantages of the present disclosure will be further clarified through the detailed description below, with reference to the accompanying drawings. The drawings are as follows: Fig. 1 is a block diagram of a dynamic wireless power transfer system;Fig. 2 is a perspective view in which a portion of a front wheel tire is transparent;Fig. 3A is a diagram of a cross-section and a partial transparent view of a side surface of the front wheel tire;Fig. 3B is a cross-sectional view of the front wheel tire;Fig. 4 is an equivalent circuit of a power transmission coil, a relay coil, and a power reception coil;Fig. 5 is a graph illustrating a relationship between a rotation angle of the tire and inductance;Fig. 6 is an explanatory diagram illustrating a manner of winding of the relay coil and a power transfer amount;Fig. 7 is an explanatory diagram illustrating a relationship between sizes of the relay coil and the power transmission coil;Fig. 8 is an explanatory diagram illustrating an example in which electric power is transferred to two relay coils;Fig. 9 is an explanatory diagram illustrating magnetic flux that is generated in the power transmission coil and leakage magnetic field;Fig. 10 is a control flowchart in which voltages in opposite phases are applied to front and rear tires;Fig. 11 is an explanatory diagram for explaining timings of voltage application to the relay coil of the front wheel tire and voltage application to the relay coil of a rear wheel tire;Fig. 12 is a control flowchart of Fig. 11;Fig. 13 is an explanatory diagram illustrating a relationship between positions of the tire and the power transmission coil when a vehicle turns on a curve;Fig. 14 is a control flowchart of Fig. 13; andFig. 15 is an explanatory diagram illustrating a position of the power transmission coil on a road. [Description of Embodiments] First embodiment: As shown in Fig. 1, a dynamic wireless power transfer system 500 according to a first embodiment includes a power transmission system 100 that is provided in a road 105 and a power reception system 200 on a vehicle 202 side. The dynamic wireless power transfer system 500 is a system that is capable of supplying electric power from the power transmission system 100 to the vehicle 202 while the vehicle 202 is traveling. For example, the vehicle 202 may be configured as an electric vehicle or a hybrid vehicle. The power transmission system 100 on the road 105 side includes a plurality of power transmission coils 40, a plurality of power transmission circuits 30 that apply an alternating-current voltage to each of the plurality of power transmission coils 40 and supply electric power, an external power supply 10 (shortened hereafter to a "power supply 10") that supplies electric power to the plurality of power transmission circuits 30, a coil position