Power transmission winding, power conversion device, and power transmission system

Abstract

The purpose of the present invention is to suppress any difference in transmission power caused by a difference in positional relationship between a power-transmission-side winding and a power-reception-side winding in contactless power supply. Two adjacent power transmission windings among power transmission windings (L1 to L4) that form an on-vehicle coil (40) are arranged such that the winding directions of conductive wires from one end to the other end are the same or opposite directions. In the power transmission windings (L1 to L4), one end of one of the two adjacent power transmission windings is connected to the other end of the other of the two adjacent power transmission windings, and the other end of the one of the two adjacent power transmission windings and the one end of the other of the two adjacent power transmission windings are connected to a first rectification circuit (32) or a second rectification circuit (34) via a resonance path that forms a resonance circuit. The resonance path includes resonance capacitors (Cs, Ct, Cu, Cv) constituting the resonance circuit together with the power transmission windings (L1 to L4).

Description

Power transmission winding, power conversion device, and power transmission system

[0001] The present invention relates to a power transmission winding, a power conversion device, and a power transmission system, and more particularly to the structure of a power transmission winding.

[0002] Electric vehicles, such as hybrid vehicles and electric vehicles, which run on battery power, are widely used. A charging device for charging the battery of an electric vehicle is installed in an automobile facility such as a parking lot. A user of the electric vehicle connects a cable extending from the charging device to the electric vehicle to charge the battery.

[0003] When charging batteries using a charging device installed in the vehicle facility, the electric vehicle must be stopped each time charging is required, which some users find to be a hassle. Furthermore, in order to reduce the frequency of charging, the electric vehicle must be equipped with a large-capacity battery, which increases the weight of the electric vehicle.

[0004] Therefore, research has been conducted on in-motion charging systems in which power transmission windings for contactless power transfer are arranged along roads. An electric vehicle is equipped with a power receiving device, which receives power from roadside windings arranged along the road through its own windings and charges its battery. Patent Document 1 and Non-Patent Document 1 listed below describe devices used in such in-motion charging systems.

[0005] Japanese Patent Application Laid-Open No. 2020-184828

[0006] : Iruretagoyena, U., Villar, I., Garcia-Bediaga, A., Mir, L. and Camblong, H., 2017. Design and characterization of a meander-type dynamic inductively coupled power transfer coil. IEEE Transactions on Industry Applications, 53(4), pp.3950-3959.

[0007] In a moving charging system, depending on the relative positions of the windings on the road side and the windings on the power receiving device side, the power supplied to the battery may be insufficient, which may result in insufficient power being supplied to the battery while the electric vehicle is moving.

[0008] The present invention aims to suppress differences in transmitted power that occur due to differences in the positional relationship between a winding on the power transmitting side and a winding on the power receiving side in contactless power feeding.

[0009] The power transmission winding according to the present invention comprises a plurality of windings, each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the windings being all connected in common, or a pair of two of the plurality of windings being connected directly or via a resonant element, the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside, or performs bidirectional AC-DC conversion between each of the windings and the outside, and power is transmitted via a path between each of the windings and the converter.

[0010] Furthermore, the power transmission winding according to the present invention comprises a plurality of windings, each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, and two adjacent windings are characterized in that one end of one of the two adjacent windings is connected to the other end of the other winding directly or via a resonant element that forms a resonant circuit, and the other end of one of the two adjacent windings and the other end of the other are connected via a resonant path that forms the resonant circuit to a converter that performs unidirectional rectification from the resonant path toward the outside, or that performs bidirectional AC / DC conversion between the resonant path and the outside.

[0011] Preferably, the converter comprises a plurality of half bridges connected in parallel, each half bridge including two rectifying elements connected in series so that one current inflow terminal is connected to the other current outflow terminal, and one of the ends of each winding that is not connected to the other winding is connected to the resonant path leading to the series connection point of the corresponding half bridge.

[0012] Preferably, the resonant path comprises a first path extending from the other end of one of the two adjacent windings to the converter, and a second path extending from the other end of the two adjacent windings to the converter, each of which includes a series capacitor and a series inductor connected in series, and an interphase capacitor provided between the connection point of the series capacitor and the series inductor in the first path and the connection point of the series capacitor and the series inductor in the second path.

[0013] Furthermore, a power transmission winding according to the present invention comprises a plurality of windings, each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of one of the windings being connected across an adjacent one of the windings to one end of another of the windings directly or via a resonant element that forms a resonant circuit, and the other end of each of the windings being connected via a resonant path that forms the resonant circuit to a converter that performs unidirectional rectification from the resonant path toward the outside or performs bidirectional AC / DC conversion between the resonant path and the outside.

[0014] Preferably, the multiple windings include a first winding to a fourth winding, and each of a first resonant path from the other end of the first winding to the converter, a second resonant path from the other end of the second winding and the other end of the third winding to the converter, and a third resonant path from the other end of the fourth winding to the converter includes a series capacitor and a series inductor connected in series, and an interphase capacitor is provided between the connection point of the series capacitor and the series inductor in the first resonant path, the connection point of the series capacitor and the series inductor in the second resonant path, and the connection point of the series capacitor and the series inductor in the third resonant path.

[0015] Preferably, the plurality of windings include a first winding to a fourth winding, and the converter includes two half bridges each including two rectifying elements connected in series so that one current inflow terminal is connected to the other current outflow terminal, the two half bridges being connected in parallel, and a capacitor bridge including two capacitors connected in series and connected in parallel to the two half bridges, wherein the other end of the first winding is connected to a first resonant path leading to a series connection point in one of the half bridges, the other ends of the second winding and the third winding are connected to a second resonant path leading to a series connection point in the capacitor bridge, and the other end of the fourth winding is connected to a third resonant path leading to a series connection point in the other half bridge.

[0016] Preferably, each of the first resonant path, the second resonant path, and the third resonant path includes a series capacitor and a series inductor connected in series, and an interphase capacitor is provided between the connection point of the series capacitor and the series inductor in the first resonant path, the connection point of the series capacitor and the series inductor in the second resonant path, and the series capacitor and the series inductor in the third resonant path.

[0017] A power conversion device according to the present invention is characterized by including the power transmission winding and the converter.

[0018] Furthermore, the power transmission system according to the present invention is characterized by comprising the power conversion device and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds an area facing two areas surrounded by two adjacent windings.

[0019] Moreover, the power transmission system according to the present invention includes the power transmission winding, and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds an area facing two areas surrounded by two adjacent windings.

[0020] Furthermore, a power transmission winding according to the present invention comprises a plurality of windings, each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the windings being connected via a circuit including a plurality of delta-connected resonance elements, and the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside or performs bidirectional AC-DC conversion between each of the windings and the outside, and power is transmitted via a path between each of the windings and the converter.

[0021] According to the present invention, it is possible to suppress a difference in transmitted power caused by a difference in the positional relationship between a winding on the power transmitting side and a winding on the power receiving side in contactless power feeding.

[0022] 1 is a diagram showing the configuration of a vehicle power transmission system according to a first embodiment. FIG. 1 is a circuit diagram of power transmission windings L1 to L4 used in an on-board power conversion device. FIG. 2 is an actual wiring diagram of the power transmission windings L1 to L4 used in an on-board power conversion device. The diagram shows the switching timing of each switching element and an outline of the time waveform of a voltage applied to a wireless transmission circuit. FIG. 3 is a diagram showing the positional relationship between a wireless transmission winding and an on-board coil, and the current flowing through the on-board coil. FIG. 4 is a diagram showing the relationship between an active coil and received power. FIG. 5 is a diagram showing the configuration of an on-board power conversion device according to a related art of the present invention. FIG. 6 is a circuit diagram of an on-board power conversion device according to a first application example. FIG. 7 is a circuit diagram of an on-board power conversion device according to a second application example. FIG. 8 is a circuit diagram of an on-board power conversion device according to a third application example. FIG. 9 is a diagram showing the configuration of a vehicle power transmission system according to a second embodiment. FIG. 10 is a circuit diagram of power transmission windings L1 to L4 used in a C / D on-board power conversion device. FIG. 11 is an actual wiring diagram of the power transmission windings L1 to L4 used in a C / D on-board power conversion device. FIG. 12 is a diagram showing the positional relationship between a wireless transmission winding and an on-board coil, and the current flowing through the on-board coil. 1 is a diagram showing a path through which a common mode current flows. FIG. 2 is a diagram showing a common mode equivalent circuit and a C / D rectifier circuit. FIG. 3 is a diagram showing a path through which a differential mode current flows. FIG. 4 is a diagram showing a differential mode equivalent circuit and a C / D rectifier circuit. FIG. 5 is a diagram showing a common mode current, a differential mode current, and received power. FIG. 6 is a circuit diagram of an on-board power conversion device according to a fourth application example. FIG. 7 is a circuit diagram of an on-board power conversion device according to a fifth application example. FIG. 8 is a circuit diagram of an on-board power conversion device according to a sixth application example. FIG. 9 is a diagram showing the configuration of a vehicle power transmission system according to a third embodiment. FIG. 10 is a diagram showing the vehicle power transmission system according to the second embodiment, in which the diodes in the rectifier circuit are replaced with switching elements. FIG. 11 is a diagram showing an on-board coil in which the winding direction of each power transmission winding is clockwise. FIG. 12 is a diagram showing the configuration of a vehicle power transmission system using an on-board coil in which the winding direction of each power transmission winding is clockwise. FIG. 13 is a diagram showing an on-board coil in which the winding direction of each power transmission winding is clockwise. FIG. 14 is a diagram showing the configuration of a C / D on-board power conversion device using an on-board coil in which the winding direction of each power transmission winding is clockwise. FIG. 10 is a circuit diagram showing a modified example of an on-board coil used in an on-board power conversion device.FIG. 1 is a circuit diagram showing a modified example of an on-board power conversion device. FIG. 2 is a circuit diagram showing a modified example of an on-board coil used in an on-board power conversion device. FIG. 3 is a circuit diagram showing a modified example of an on-board power conversion device. FIG. 4 is a circuit diagram showing a modified example of an on-board coil used in a C / D on-board power conversion device. FIG. 5 is a circuit diagram showing a modified example of a C / D on-board power conversion device. FIG. 6 is a circuit diagram showing a modified example of an on-board coil used in a C / D on-board power conversion device. FIG. 7 is a diagram showing a circuit diagram of an on-board power conversion device.

[0023] An embodiment of the present invention will be described with reference to the drawings. Identical components shown in multiple drawings will be assigned the same reference numerals to simplify the description. Terms indicating directions such as up, down, left, and right in this specification refer to directions in the drawings unless otherwise specified. These terms are used for convenience of explanation and do not limit the orientation of each component when it is arranged.

[0024] FIG. 1 shows the configuration of a vehicle power transmission system 100 according to a first embodiment of the present invention. The vehicle power transmission system 100 includes a power transmission device 12, multiple wireless transmission circuits 20, and an on-board power conversion device 18 (power conversion device). The vehicle power transmission system 100 supplies power from the power transmission device 12 to the on-board power conversion device 18 via the wireless transmission circuit 20. The vehicle power transmission system 100 also constitutes a traveling power transmission system. The on-board power conversion device 18 is mounted on an electric vehicle 24, and a battery mounted on the electric vehicle 24 is charged by the power supplied from the power transmission device 12. The wireless transmission windings 16 provided in each of the multiple wireless transmission circuits 20 are arranged along a road, so that the battery is charged even when the electric vehicle 24 is traveling on the road.

[0025] The power transmission device 12 includes a DC voltage source 30, an input capacitor Ci, a first half switching bridge B1, and a second half switching bridge B2. Each wireless transmission circuit 20 includes a resonant capacitor Ca and a wireless transmission winding 16 connected in series. In the example shown in FIG. 1 , the multiple wireless transmission circuits 20 are connected in parallel, but the multiple wireless transmission circuits 20 may also be connected in series. Furthermore, some of the multiple wireless transmission circuits 20 may be connected in parallel, and other parts may be connected in series to the parallel-connected parts.

[0026] The DC voltage source 30 may include an AC / DC converter that converts AC power supplied from a commercial power supply system (electric power grid) into DC power. Alternatively, the DC voltage source 30 may be a battery. The first half switching bridge B1 includes switching elements S1 and S2 connected in series, and the second half switching bridge B2 includes switching elements S3 and S4 connected in series.

[0027] The switching elements S1 to S4 may be semiconductor elements such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors). Two MOSFETs connected in series means that the source of one MOSFET is connected to the drain of the other MOSFET. Two IGBTs connected in series means that the collector of one IGBT is connected to the emitter of the other IGBT.

[0028] The input capacitor Ci, the first half switching bridge B1, and the second half switching bridge B2 are connected in parallel. One end of a resonant capacitor Ca is connected to the connection point of the switching elements S1 and S2 of the first half switching bridge B1. One end of a wireless transmission winding 16 is connected to the other end of the resonant capacitor Ca. The other end of the wireless transmission winding 16 is connected to the connection point of the switching elements S3 and S4 of the second half switching bridge B2.

[0029] The onboard power conversion device 18 includes power transmission windings L1 to L4, resonant capacitors Cs, Ct, Cu, and Cv, a first rectifier circuit 32, and a second rectifier circuit 34. Of the two ends of each of the power transmission windings L1 to L4, the end marked with a black dot is the reference end. The reference end is defined as the terminal at which an induced electromotive force of the same polarity appears when magnetic flux linking two adjacent power transmission windings in the same direction increases or decreases. In the following description, the terminal of each of the power transmission windings L1 to L4 opposite the reference end is referred to as the dependent end. However, the terms reference end and dependent end are used for convenience to distinguish the polarity of the windings and do not limit the winding structure, such as the winding method.

[0030] The dependent end of the power transmission winding L1, the reference end of the power transmission winding L2, the dependent end of the power transmission winding L3, and the reference end of the power transmission winding L4 are commonly connected.

[0031] The first rectifier circuit 32 and the second rectifier circuit 34 each include a half rectifier bridge HD1, HD2, and a smoothing capacitor Cm connected in parallel. Each half rectifier bridge HD1, HD2 includes a first diode D1 and a second diode D2, with the anode of the first diode D1 connected to the cathode of the second diode D2. A pair of parallel-connected terminals of the half rectifier bridge HD1, HD2, and the smoothing capacitor Cm constitutes a pair of output terminals, i.e., a positive terminal p and a negative terminal n, of the first rectifier circuit 32 and the second rectifier circuit 34, respectively. The positive terminal p and the negative terminal n of the first rectifier circuit 32 and the second rectifier circuit 34 are commonly connected. The positive terminal p of the first rectifier circuit 32 and the second rectifier circuit 34 is connected to the positive terminal of the battery 36, and the negative terminal n of the first rectifier circuit 32 is connected to the negative terminal of the battery 36.

[0032] A load device may be connected in parallel to the battery 36. The load device may include, for example, a circuit that drives a motor that drives the electric vehicle 24. Alternatively, a load device may be connected instead of the battery 36.

[0033] The first diode D1 and the second diode D2 serving as rectifying elements may be replaced by switching elements through which current flows in one direction, such as thyristors or transistors. In this case, two rectifying elements (switching elements) constituting each half rectifying bridge are connected in series so that the current inflow terminal of one is connected to the current outflow terminal of the other.

[0034] The reference end of the power transmission winding L1 is connected to one end of a resonant capacitor Cs. The other end of the resonant capacitor Cs is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the first rectifier circuit 32. The dependent end of the power transmission winding L2 is connected to one end of a resonant capacitor Ct. The other end of the resonant capacitor Ct is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the first rectifier circuit 32.

[0035] The reference end of the power transmission winding L3 is connected to one end of a resonant capacitor Cu. The other end of the resonant capacitor Cu is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the second rectifier circuit 34. The dependent end of the power transmission winding L4 is connected to one end of a resonant capacitor Cv. The other end of the resonant capacitor Cv is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the second rectifier circuit 34.

[0036] FIG. 2 shows a circuit diagram of the power transmission windings L1 to L4. Each of the power transmission windings L1 to L4 is formed by a conductor wire into a flat rectangular loop. The power transmission windings L1 to L4 are arranged in a row in a specific direction so that the areas where the conductor wire turns do not overlap. The power transmission windings L1 to L4 have the same number of turns. That is, each of the power transmission windings L1 to L4 is formed by a conductor wire that turns counterclockwise in a rectangular shape the same number of times from the reference end to the dependent end. In two adjacent power transmission windings, the conductor wires corresponding to the vertically extending sides are arranged close to each other. When magnetic flux linking two adjacent power transmission windings in the same direction increases or decreases, induced electromotive forces of the same polarity appear at the reference ends of the two adjacent power transmission windings, with the dependent ends as the reference.

[0037] FIG. 3 shows an actual wiring diagram of the power transmission windings L1 to L4. The conductors 42 constituting the power transmission windings L1 to L4 may be metal wires coated with an insulator. Each of the power transmission windings L1 to L4 is formed by a conductor 42 fitted into a groove formed in the surface of a magnetic plate 38. The magnetic plate 38 may be formed of a magnetic material such as ferrite. At the locations where the conductors 42 intersect, as shown in the enlarged view at the bottom of FIG. 3 , the grooves are formed so that the groove into which the lower conductor 42 is fitted is deeper than the groove into which the upper conductor is fitted. The reference end of the power transmission winding L1, the dependent end of the power transmission winding L2, the reference end of the power transmission winding L3, and the dependent end of the power transmission winding L4 are connected to connection terminals s, t, u, and v, respectively. The connection terminals s, t, u, and v are terminals for connection to other circuits. In this way, the power transmission windings L1 to L4 and the magnetic plate 38 form the on-board coil 40 in which the multiple windings do not overlap in the area where the conductive wire 42 turns around.

[0038] In this way, the power transmission windings L1 to L4 that form the on-board coil 40 are arranged so that two adjacent power transmission windings have the same winding direction of the conductor from one end to the other.

[0039] In the power transmission windings L1 to L4, one end of one of two adjacent power transmission windings is connected to the other end of the other, and the other end of one of the two adjacent power transmission windings and one end of the other are connected to the first rectifier circuit 32 or the second rectifier circuit 34 via a resonant path that forms a resonant circuit. The first rectifier circuit 32 and the second rectifier circuit 34 are converters that perform rectification in one direction from the resonant path toward the outside. In the embodiment shown in FIGS. 1 to 3, the resonant path is made up of resonant capacitors Cs, Ct, Cu, and Cv that form a resonant circuit together with the power transmission windings L1 to L4.

[0040] Each of the first rectifier circuit 32 and the second rectifier circuit 34 includes two half bridges HD1 and HD2, each including a first diode D1 and a second diode D2 (two rectifier elements) connected in series such that one current-in terminal (anode) is connected to the other current-out terminal (cathode). These two half rectifier bridges HD1 and HD2 are connected in parallel.

[0041] Charts (a) to (c) of Fig. 4 show the switching timing of the switching elements S1 to S4 included in the power transmission device 12 and the general time waveform of the voltage Vin applied to the wireless transmission circuit 20. Chart (a) of Fig. 4 shows the control signal g1 for the switching element S1. When the level of the control signal g1 is high, the switching element S1 is turned on and the switching element S2 is turned off. Chart (b) of Fig. 4 shows the control signal g3 for the switching element S3. When the level of the control signal g3 is high, the switching element S3 is turned on and the switching element S4 is turned off. Chart (c) of Fig. 4 shows the voltage Vin applied to the wireless transmission circuit 20.

[0042] Switching elements S1 and S2 alternately switch on and off. That is, when switching element S1 switches from off to on, switching element S2 switches from on to off. Switching elements S3 and S4 also alternately switch on and off. The switching phase of switching elements S3 and S4 lags behind the switching phase of switching elements S1 and S2 by 180°-δ, where δ is a phase angle smaller than 180°.

[0043] While the phase angle is between 0° and 180°-δ, switching elements S1 and S4 are on, and switching elements S2 and S3 are off. During this first period, a voltage Vdc is applied to the wireless transmission circuit 20. While the phase angle is between 180°-δ and 180°, switching elements S1 and S3 are on, and switching elements S2 and S4 are off. During this second period, the voltage applied to the wireless transmission circuit 20 is 0. While the phase angle is between 180° and 360°-δ, switching elements S1 and S4 are off, and switching elements S2 and S3 are on. During this third period, a voltage −Vdc is applied to the wireless transmission circuit 20. While the phase angle is between 360°-δ and 360°, switching elements S1 and S3 are off, and switching elements S2 and S4 are on. During this fourth period, the voltage applied to the wireless transmission circuit 20 is 0.

[0044] In this way, by switching the switching elements S1 to S4, the voltage Vin applied to the wireless transmission circuit 20 repeats over time as follows: Vdc, 0, −Vdc, 0, Vdc, 0, −Vdc, . . .

[0045] Charts (a) to (c) in FIG. 5 show the positional relationship between the wireless transmission winding 16 and the on-board coil 40, and the current flowing through the on-board coil 40, when the electric vehicle 24 passes above the wireless transmission winding 16. The on-board coil 40 is fixed below the electric vehicle 24 on which it is mounted. The wireless transmission winding 16 is located on a site with a road or a parking lot, etc. The wireless transmission winding 16 is formed in a flat loop shape, and is shaped and sized to face two adjacent ones of the power transmission windings L1 to L4. In other words, the wireless transmission winding 16 is shaped and sized to surround an area facing two areas surrounded by two adjacent power transmission windings. The magnetic flux emitted from the wireless transmission winding 16 interlinks with two adjacent ones of the power transmission windings L1 to L4 that face the wireless transmission winding 16.

[0046] The wireless transmission windings 16 are repeatedly arranged along the road at intervals of normalized distance 3, where the distance between the center points of the power transmission windings L1 to L4 in the arrangement direction of the power transmission windings L1 to L4 is used as a unit of normalized distance. The thick arrows shown in charts (a) to (c) of Fig. 5 conceptually show the induced currents flowing in the power transmission windings L1 to L4.

[0047] Chart (a) of Fig. 5 shows a state in which the magnetic flux emitted from the wireless transmission winding 16 links with the power transmission windings L3 and L4, the magnetic flux changes over time, and an induced current flows in the power transmission windings L3 and L4. Chart (b) of Fig. 5 shows a state in which the magnetic flux emitted from the wireless transmission winding 16 links with the power transmission windings L2 and L3, the magnetic flux changes over time, and an induced current flows in the power transmission windings L2 and L3. Chart (c) of Fig. 5 shows a state in which the magnetic flux emitted from the wireless transmission winding 16 links with the power transmission windings L1 and L2, the magnetic flux changes over time, and an induced current flows in the power transmission windings L1 and L2.

[0048] In this way, as the electric vehicle 24 moves from upstream to downstream on the road, the on-board coil 40 also moves from upstream to downstream on the road. The magnetic flux emitted from the wireless transmission winding 16 sequentially links the pair of power transmission windings L3 and L4, the pair of power transmission windings L2 and L3, and the pair of power transmission windings L1 and L2, in that order. The voltage Vin applied to the wireless transmission circuit 20 that constitutes the wireless transmission winding 16 changes over time as shown in FIG. 4 , and as the voltage Vin applied to the wireless transmission winding 16 changes over time, the magnetic flux emitted from the wireless transmission winding 16 changes, and an induced electromotive force is generated in each power transmission winding, causing an induced current to flow in the pair of power transmission windings L3 and L4, the pair of power transmission windings L2 and L3, and the pair of power transmission windings L1 and L2, in that order.

[0049] Referring back to Figure 1, the generation of an induced electromotive force in the power transmission windings L3 and L4 causes a resonant circuit formed by the power transmission winding L3 and resonant capacitor Cu and a resonant circuit formed by the power transmission winding L4 and resonant capacitor Cv to resonate, and an induced current corresponding to the resonant state flows through each resonant circuit. The induced current is rectified by the half rectifier bridges HD1 and HD2 of the second rectifier circuit 34, and charges the smoothing capacitor Cm and the battery 36.

[0050] The generation of an induced electromotive force in the power transmission windings L2 and L3 causes a resonant circuit formed by the power transmission winding L2 and the resonant capacitor Ct and a resonant circuit formed by the power transmission winding L3 and the resonant capacitor Cu to resonate, and an induced current corresponding to the resonant state flows through each resonant circuit. The induced current is rectified by the half rectifier bridge HD2 of the first rectifier circuit 32 and the half rectifier bridge HD1 of the second rectifier circuit 34, and charges the smoothing capacitor Cm and the battery 36.

[0051] The generation of an induced electromotive force in the power transmission windings L1 and L2 causes a resonant circuit formed by the power transmission winding L1 and resonant capacitor Cs and a resonant circuit formed by the power transmission winding L2 and resonant capacitor Ct to resonate, and an induced current corresponding to the resonant state flows through each resonant circuit. The induced current is rectified by the half rectifier bridges HD1 and HD2 of the first rectifier circuit 32, and charges the smoothing capacitor Cm and the battery 36.

[0052] 2 and 3 , the direction of the induced current flowing due to the change in magnetic flux emitted from the wireless transmission winding 16 is opposite in the conductor corresponding to the right vertical side of the power transmission winding L3 and the conductor corresponding to the left vertical side of the power transmission winding L4. Therefore, the power transmission windings L3 and L4 are in a state similar to a state in which the induced current flows along the outer periphery formed by the left and upper and lower sides of the power transmission winding L3 and the right and upper and lower sides of the power transmission winding L4. Similarly, the power transmission windings L2 and L3 are in a state similar to a state in which the induced current flows along the outer periphery formed by the left and upper and lower sides of the power transmission winding L2 and the right and upper and lower sides of the power transmission winding L3. Similarly, the power transmission windings L1 and L2 are in a state similar to a state in which the induced current flows along the outer periphery formed by the left and upper and lower sides of the power transmission winding L1 and the right and upper and lower sides of the power transmission winding L2.

[0053] 6 shows the relationship between the active coil and the received power when the electric vehicle 24 travels from the upstream side to the downstream side of the road. The horizontal axis represents the position of the on-board coil 40 expressed as a normalized distance, and the vertical axis represents the received power. Here, the active coil refers to the power transmission winding with which the magnetic flux emitted from the wireless transmission winding 16 interlinks.

[0054] As the electric vehicle 24 travels, the active coils are repeated in the following order: a set of power transmission windings L3 and L4, a set of power transmission windings L2 and L3, a set of power transmission windings L1 and L2, a set of power transmission windings L3 and L4, etc. However, the middle section of Fig. 6 only illustrates the wireless transmission windings 16 that face each power transmission winding in the first period in which the sets of power transmission windings that become active coils are repeated; it does not illustrate the wireless transmission windings 16 that face each power transmission winding in the second period that follows the first period. The winding directions of the wireless transmission windings 16 that face each power transmission winding are opposite to those of the first period and the second period. Therefore, the time waveform of the received power is symmetrical with respect to the position at the normalized distance of 2.5.

[0055] FIG. 7 shows the configuration of an onboard power conversion device 200 according to a related art of the present invention. The onboard power conversion device 200 is obtained by extracting the power transmission windings L1 and L2, the resonant capacitors Cs and Ct, and the first rectifier circuit 32 from the onboard power conversion device 18 shown in FIG. 1 , and reversing the connection of the reference terminal and the dependent terminal of the power transmission winding L2. In the onboard power conversion device 200, when magnetic flux emitted from the wireless transmission winding 16 simultaneously interlinks with the power transmission windings L1 and L2, the induced current flowing through the power transmission winding L1 and the induced current flowing through the power transmission winding L2 cancel each other out or subtract each other. Therefore, in a vehicle power transfer system using the onboard power conversion device 200, the received power may be reduced depending on the positional relationship between the wireless transmission winding and the power transmission windings L1 and L2. As a result, as the electric vehicle travels, a minimum point where the received power is zero or close to zero may appear in the received power.

[0056] The vehicle power transmission system 100 according to the embodiment of the present invention suppresses fluctuations in received power according to the positional relationship between the wireless transmission winding 16 and the power transmission windings L1 to L4. This prevents the appearance of minimum points of 0 or near 0 in the waveform of the received power, suppressing fluctuations in received power that accompany the running of the electric vehicle 24.

[0057] Furthermore, the vehicle power transmission system 100 according to this embodiment uses an on-board coil 40 in which multiple windings do not overlap, as shown in FIG. 3 . This increases the gap between the bottom of the electric vehicle 24 and the roadway, making it easier for the electric vehicle 24 to travel in areas with obstacles such as steps and stones. Furthermore, since the on-board coil 40 does not have multiple windings that overlap, and each power transmission winding is formed flat, heat dissipation is facilitated. Furthermore, the on-board coil 44 has a simple structure, which is advantageous from the viewpoints of reducing manufacturing costs and improving fuel efficiency.

[0058] FIG. 8 shows a circuit diagram of an on-board power conversion device 50 according to a first application example. The on-board power conversion device 50 includes power transmission windings L1, L2, and L3, resonant capacitors Cs, Ct, and Cu, and a three-phase rectifier circuit 52. The on-board power conversion device 50 is similar to the on-board power conversion device 18 according to the first embodiment except that the power transmission winding L4, resonant capacitor Cv, and second rectifier circuit 34 are removed, and a half rectifier bridge HD3 is added to the first rectifier circuit 32 to form the three-phase rectifier circuit 52. The half rectifier bridge HD3 is connected in parallel to the half rectifier bridges HD1 and HD2. One end of the resonant capacitor Cu, the end not connected to the power transmission winding L3, is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD3.

[0059] The magnetic flux emitted from the wireless transmission winding 16 sequentially interlinks with the pair of power transmission windings L2 and L3 and then the pair of power transmission windings L1 and L2, or with the pair of power transmission windings L1 and L2 and then the pair of power transmission windings L2 and L3, as the electric vehicle 24 travels. As the voltage Vin applied to the wireless transmission circuit 20 changes, and the voltage applied to the wireless transmission winding 16 changes, the magnetic flux emitted from the wireless transmission winding 16 changes, and induced electromotive forces are generated in each power transmission winding in the order of the pair of power transmission windings L2 and L3 and then the pair of power transmission windings L1 and L2, or with the pair of power transmission windings L1 and L2 and then the pair of power transmission windings L2 and L3.

[0060] The generation of an induced electromotive force in the power transmission windings L2 and L3 causes a resonant circuit formed by the power transmission winding L2 and the resonant capacitor Ct and a resonant circuit formed by the power transmission winding L3 and the resonant capacitor Cu to resonate, and an induced current corresponding to the resonant state flows through each resonant circuit. The induced current is rectified by the half rectifier bridges HD2 and HD3, and charges the smoothing capacitor Cm and the battery 36.

[0061] The generation of an induced electromotive force in the power transmission windings L1 and L2 causes a resonant circuit formed by the power transmission winding L1 and the resonant capacitor Cs and a resonant circuit formed by the power transmission winding L2 and the resonant capacitor Ct to resonate, and an induced current corresponding to the resonant state flows through each resonant circuit. The induced current is rectified by the half rectifier bridges HD1 and HD2, and charges the smoothing capacitor Cm and the battery 36.

[0062] 9 shows a circuit diagram of an on-board power conversion device 54 according to a second application example. The on-board power conversion device 54 is configured by replacing the resonant capacitors Cs, Ct, Cu, and Cv in the on-board power conversion device 18 with an LCC resonant circuit 56. The LCC resonant circuit 56 includes series capacitors C1 to C4, series inductors Ls1 to Ls4, and interphase capacitors C12, C23, and C34.

[0063] The series capacitor C1 and the series inductor Ls1 are connected in series. Similarly, the series capacitor C2 and the series inductor Ls2, the series capacitor C3 and the series inductor Ls3, and the series capacitor C4 and the series inductor Ls4 are also connected in series. An interphase capacitor C12 is connected between the connection point between the series capacitor C1 and the series inductor Ls1 and the connection point between the series capacitor C2 and the series inductor Ls2. Similarly, an interphase capacitor C23 is connected between the connection point between the series capacitor C2 and the series inductor Ls2 and the connection point between the series capacitor C3 and the series inductor Ls3, and an interphase capacitor C34 is connected between the connection point between the series capacitor C3 and the series inductor Ls3 and the connection point between the series capacitor C4 and the series inductor Ls4. One end of the series inductor Ls1 that is not connected to the series capacitor C1 is connected to the connection point between the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the first rectifier circuit 32. The end of the series inductor Ls2 that is not connected to the series capacitor C2 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the first rectifier circuit 32. The end of the series inductor Ls3 that is not connected to the series capacitor C3 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the second rectifier circuit 34. The end of the series inductor Ls4 that is not connected to the series capacitor C4 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the second rectifier circuit 34.

[0064] Thus, the on-board power conversion device 54 according to the second application example includes series-connected series capacitors C1 to C4 and series inductors Ls1 to Ls4 provided on each of a first path extending from the other end of one of two adjacent power transmission windings among the power transmission windings L1 to L4 to the rectifier circuit (first rectifier circuit 32 or second rectifier circuit 34) and a second path extending from the other end of the other of the two adjacent power transmission windings to the rectifier circuit. The on-board power conversion device 54 also includes interphase capacitors C12, C23, and C34 provided between the junction of the series capacitor and the series inductor in the first path and the junction of the series capacitor and the series inductor in the second path.

[0065] The LCC resonant circuit 56, through its impedance conversion function, suppresses changes in the load impedance on the power transmission side due to changes in the state of charge of the battery 36. Here, the state of charge of the battery 36 includes SOC, etc. The load impedance on the power transmission side is defined as the impedance of the wireless transmission circuit 20 shown in FIG.

[0066] When a load device is connected in parallel to the battery 36 or when a load device is connected in place of the battery 36, a change in the load impedance on the power transmission side in response to a change in the impedance of the load device is suppressed, which makes it easier to control the power transmitted from the power transmission device 12 to the on-board power conversion device 18.

[0067] 10 shows a circuit diagram of an on-board power conversion device 54 according to a third application example. The on-board power conversion device 54 is configured by providing a filter circuit 57 between the resonant capacitors Cs, Ct, Cu, and Cv in the on-board power conversion device 18 according to the first embodiment and the first rectifier circuit 32 and the second rectifier circuit 34. The filter circuit 57 suppresses noise currents flowing through the power transmission windings L1 to L4 based on the nonlinearity of the diodes provided in each of the first rectifier circuit 32 and the second rectifier circuit 34, and suppresses noise electromagnetic waves emitted from the power transmission windings L1 to L4.

[0068] The filter circuit 57 includes a series resonant circuit SR1 provided on a first path 58-1 from the resonant capacitor Cs to the half rectifier bridge HD1 of the first rectifier circuit 32, and a series resonant circuit SR2 provided on a second path 58-2 from the resonant capacitor Ct to the half rectifier bridge HD2 of the first rectifier circuit 32. The filter circuit 57 further includes a series resonant circuit SR3 provided on a third path 58-3 from the resonant capacitor Cu to the half rectifier bridge HD1 of the second rectifier circuit 34, and a series resonant circuit SR4 provided on a fourth path 58-4 from the resonant capacitor Cv to the half rectifier bridge HD2 of the second rectifier circuit 34. Each of the series resonant circuits SR1 to SR4 is formed by connecting an inductor and a capacitor in series.

[0069] The filter circuit 57 further includes a parallel resonant circuit PR12 provided between the first path 58-1 and the second path 58-2, a parallel resonant circuit PR23 provided between the second path 58-2 and the third path 58-3, and a parallel resonant circuit PR34 provided between the third path 58-3 and the fourth path 58-4. Each of the parallel resonant circuits PR12, PR23, and PR34 is formed by connecting an inductor and a capacitor in parallel. However, each parallel resonant circuit is provided between each of the resonant capacitors Cs, Ct, Cu, and Cv and one of the series resonant circuits SR1 to SR4.

[0070] Any of the series resonant circuits SR1 to SR4 and the parallel resonant circuits PR12, PR23, and PR34 may be omitted. Furthermore, the element constants of the inductors and capacitors included in each series resonant circuit and each parallel resonant circuit may be determined according to the switching frequency of the power transfer device 12.

[0071] 11 shows the configuration of a vehicle power transmission system 102 according to a second embodiment of the present invention. The vehicle power transmission system 102 includes a power transmission device 12, multiple wireless transmission circuits 60, and a common / differential mode onboard power conversion device 70 (power conversion device). The common / differential mode onboard power conversion device 70 will be referred to as a C / D onboard power conversion device 70 hereinafter. Here, the term "C / D" is an abbreviation for Common Mode / Differential Mode. The vehicle power transmission system 102 is similar to the vehicle power transmission system 100 according to the first embodiment, except that the wireless transmission circuit 20 and the onboard power conversion device 18 are replaced with the wireless transmission circuit 60 and the C / D onboard power conversion device 70, which will be described below, respectively.

[0072] Each wireless transmission circuit 60 includes a power transmitting inductor La, a power transmitting parallel capacitor Cx, a power transmitting series capacitor Cy, and a wireless transmission winding 16, and constitutes an LCC resonant circuit. One end of the power transmitting inductor La is connected to the connection point of the switching elements S1 and S2. The other end of the power transmitting inductor La is connected to one end of the power transmitting series capacitor Cy. The other end of the power transmitting series capacitor Cy is connected to one end of the wireless transmission winding 16, and the other end of the wireless transmission winding 16 is connected to the connection point of the switching elements S3 and S4. A power transmitting parallel capacitor Cx is connected between the connection point of the power transmitting inductor La and the power transmitting series capacitor Cy and the path from the wireless transmission winding 16 to the switching elements S3 and S4.

[0073] The C / D in-vehicle power conversion device 70 includes power transmission windings L1 to L4, a C / D resonance circuit 72, and a C / D rectifier circuit 74. The C / D resonance circuit 72 includes series capacitors C1, C0, and C4, interphase capacitors C10, C40, and C14, and series inductors Ls1, Ls0, and Ls4.

[0074] The dependent ends of the power transmission windings L1 and L3 are commonly connected, the dependent ends of the power transmission windings L2 and L4 are commonly connected, and the reference ends of the power transmission windings L2 and L3 are commonly connected.

[0075] The C / D rectifier circuit 74 includes half rectifier bridges HD1 and HD2 connected in parallel and a capacitor bridge CB. The capacitor bridge CB includes a first smoothing capacitor Cm1 and a second smoothing capacitor Cm2 connected in series. A pair of parallel-connected terminals of the half rectifier bridges HD1 and HD2 and the capacitor bridge CB constitute a pair of output terminals of the C / D rectifier circuit 74, i.e., a positive terminal p and a negative terminal n. The positive terminal p of the C / D rectifier circuit 74 is connected to the positive electrode of the battery 36, and the negative terminal n is connected to the negative electrode of the battery 36. A load device may be connected in parallel to the battery 36. The load device may include, for example, a circuit for driving a motor that drives the electric vehicle 24. Alternatively, a load device may be connected instead of the battery 36.

[0076] The reference end of the power transmission winding L1 is connected to one end of a series capacitor C1. The other end of the series capacitor C1 is connected to one end of a series inductor Ls1. The other end of the series inductor Ls1 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1.

[0077] The reference end of the power transmission winding L4 is connected to one end of a series capacitor C4. The other end of the series capacitor C4 is connected to one end of a series inductor Ls4. The other end of the series inductor Ls4 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2.

[0078] The connection ends of the power transmission windings L2 and L3 are connected to one end of a series capacitor C0. The other end of the series capacitor C0 is connected to one end of a series inductor Ls0. The other end of the series inductor Ls0 is connected to the connection point of the first smoothing capacitor Cm1 and the second smoothing capacitor Cm2 of the capacitor bridge CB.

[0079] The interphase capacitor C10 is connected between the connection point of the series capacitor C1 and the series inductor Ls1 and the connection point of the series capacitor C0 and the series inductor Ls0. The interphase capacitor C40 is connected between the connection point of the series capacitor C4 and the series inductor Ls4 and the connection point of the series capacitor C0 and the series inductor Ls0. The interphase capacitor C14 is connected between the connection point of the series capacitor C1 and the series inductor Ls1 and the connection point of the series capacitor C4 and the series inductor Ls4.

[0080] 12 shows a circuit diagram of the power transmission windings L1 to L4 used in the C / D in-vehicle power conversion device 70. The power transmission windings L1 to L4 in this embodiment are connected differently from the power transmission windings L1 to L4 in the first embodiment. A subordinate end of the power transmission winding L1 and a subordinate end of the power transmission winding L3 are connected in common, and a subordinate end of the power transmission winding L2 and a subordinate end of the power transmission winding L4 are connected in common. Furthermore, a reference end of the power transmission winding L2 and a reference end of the power transmission winding L3 are connected in common.

[0081] Fig. 13 shows an actual wiring diagram of the power transmission windings L1 to L4. Like the power transmission windings L1 to L4 according to the first embodiment, the power transmission windings L1 to L4 may be configured with a magnetic plate 38 and a conductor 42. The power transmission windings L1 to L4 and the magnetic plate 38 form an on-board coil 44 in which multiple windings do not overlap in the area where the conductor 42 winds around. The power transmission windings L1 to L4 shown in Fig. 13 may have the same structure as the power transmission windings L1 to L4 shown in Fig. 3, except that the connection mode of these windings differs from that of the power transmission windings L1 to L4 shown in Fig. 3.

[0082] In this way, the power transmission windings L1 to L4 that form the on-board coil 44 have the same winding direction from one end to the other, and one end of one power transmission winding is connected to one end of another power transmission winding across an adjacent power transmission winding. In the embodiments shown in FIGS. 11 to 13, the "one end" corresponds to the dependent end, and the "other end" corresponds to the reference end. The other end of each power transmission winding is connected to a rectifier circuit, i.e., a C / D rectifier circuit 74, via a resonant path that forms a resonant circuit. In the embodiment shown in FIG. 11, the resonant path corresponds to a C / D resonance circuit 72 that forms a resonant circuit together with the power transmission windings L1 to L4.

[0083] In the vehicle power transmission system 102 shown in FIG. 11 , the C / D rectifier circuit 74 includes a capacitor bridge CB including a first smoothing capacitor Cm1 and a second smoothing capacitor Cm2 connected in series in addition to parallel-connected half rectifier bridges HD1 and HD2, and the capacitor bridge CB is connected in parallel to the half rectifier bridges HD1 and HD2. The reference end of the power transmission winding L1 serving as a first winding is connected to a first resonant path leading to the series connection point of one half rectifier bridge HD1. The reference end of the power transmission winding L2 serving as a second winding and the reference end of the power transmission winding L3 serving as a third winding are connected to a second resonant path leading to the series connection point of the capacitor bridge CB. The reference end of the power transmission winding L4 serving as a fourth winding is connected to a third resonant path leading to the series connection point of the other half rectifier bridge HD2. The first to third resonant paths are included in the C / D resonant circuit 72.

[0084] Furthermore, each of a first resonant path from the reference end of power transmission winding L1 to C / D rectifier circuit 74, a second resonant path from the reference end of power transmission winding L2 and the reference end of power transmission winding L3 to C / D rectifier circuit 74, and a third resonant path from the reference end of power transmission winding L4 to C / D rectifier circuit 74 includes a series capacitor and a series inductor connected in series. Interphase capacitors C10, C40, and C14 are provided between the connection point of series capacitor C1 and series inductor Ls1 in the first resonant path, the connection point of series capacitor C0 and series inductor Ls0 in the second resonant path, and the connection point of series capacitor C4 and series inductor Ls4 in the third resonant path.

[0085] Charts (a) to (c) in Fig. 14 show the positional relationship between the wireless transmission winding 16 and the on-board coil 44 and the current flowing through the on-board coil 44 when the electric vehicle 24 moves from the upstream side to the downstream side of the road. The wireless transmission winding 16 is formed in a flat loop shape and has a shape and size that faces two adjacent ones of the power transmission windings L1 to L4. That is, the wireless transmission winding 16 is formed in a shape and size that surrounds an area that faces two areas surrounded by two adjacent power transmission windings. The magnetic flux emitted from the wireless transmission winding 16 interlinks with two adjacent ones of the power transmission windings L1 to L4 that face the wireless transmission winding 16. The wireless transmission winding 16 is repeatedly arranged along the road at intervals of a normalized distance of 3, where the distance between the center points of the power transmission windings L1 to L4 in the arrangement direction of the power transmission windings L1 to L4 is used as a unit of normalized distance.

[0086] Chart (a) in Figure 14 shows a state in which magnetic flux emitted from the wireless transmission winding 16 on the upstream side of the road interlinks with the power transmission windings L2 and L3, and this magnetic flux changes over time, causing an induced current to flow through the power transmission windings L2 and L3. This induced current is a common-mode current. The induced current flows into the reference ends of the power transmission windings L2 and L3, flows from the dependent ends of the power transmission windings L2 and L3 to the dependent ends of the power transmission windings L4 and L1, respectively, and then flows out from the reference ends of the power transmission windings L4 and L1. Alternatively, the induced current flows into the reference ends of the power transmission windings L4 and L1, flows from the dependent ends of the power transmission windings L4 and L1 to the dependent ends of the power transmission windings L2 and L3, respectively, and flows out from the reference ends of the power transmission windings L2 and L3.

[0087] Chart (b) in Figure 14 shows a state in which magnetic flux emitted from the wireless transmission winding 16 on the upstream side of the road links to the power transmission winding L1, and magnetic flux emitted from the wireless transmission winding 16 on the downstream side of the road links to the power transmission winding L4. The magnetic flux linkage between the power transmission windings L1 and L4 changes over time, causing an induced current to flow through the power transmission windings L1 and L4. This induced current is a differential mode current. The induced current flows into the reference end of the power transmission winding L1, flows from the dependent end of the power transmission winding L1 to the dependent end of the power transmission winding L3, and flows from the reference end of the power transmission winding L3 to the reference end of the power transmission winding L2. The induced current also flows from the dependent end of the power transmission winding L2 to the dependent end of the power transmission winding L4 and flows out from the reference end of the power transmission winding L4. Alternatively, the induced current flows into the reference end of power transmission winding L4, flows from the dependent end of power transmission winding L4 to the dependent end of power transmission winding L2, and flows from the reference end of power transmission winding L2 to the reference end of power transmission winding L3. The induced current also flows from the dependent end of power transmission winding L3 to the dependent end of power transmission winding L1 and flows out of the reference end of power transmission winding L1.

[0088] Chart (c) in Figure 14 shows a state in which magnetic flux emitted from the wireless transmission winding 16 on the downstream side of the road interlinks with the power transmission windings L2 and L3, and the magnetic flux changes over time, causing an induced current to flow in the power transmission windings L2 and L3. This induced current is a common mode current. The induced current flows through a path similar to that shown in chart (a) in Figure 14.

[0089] In this way, as the electric vehicle 24 moves from upstream to downstream on the road, the on-board coil 44 also moves from upstream to downstream on the road. After the magnetic flux emitted from the upstream wireless transmission winding 16 links to the power transmission windings L2 and L3, the magnetic flux emitted from the upstream wireless transmission winding 16 links to the power transmission winding L1, and the magnetic flux emitted from the downstream wireless transmission winding 16 links to the power transmission winding L4. After that, the magnetic flux emitted from the downstream wireless transmission winding 16 links to the power transmission windings L2 and L3. As the voltage Vin applied to the wireless transmission circuit 60 changes over time as shown in FIG. 4 , the voltage applied to each wireless transmission winding 16 changes over time. This causes a change in the magnetic flux emitted from each wireless transmission winding 16, and an induced electromotive force is generated in each power transmission winding in the following order: the pair of power transmission windings L2 and L3, the pair of power transmission windings L1 and L4, and the pair of power transmission windings L2 and L3.

[0090] 15 shows the path through which the common-mode current ic flows. The common-mode current ic flows from the junction of the first smoothing capacitor Cm1 and the second smoothing capacitor Cm2 of the capacitor bridge CB, through the series inductor Ls0 and the series capacitor C0, to the reference ends of the power transmission windings L2 and L3. Half of the common-mode current ic flows from the power transmission winding L2, through the power transmission winding L4, the series capacitor C4, and the series inductor Ls4, to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2.

[0091] The remaining half of the common-mode current i c , c / 2, flows through a path from the power transmission winding L3 through the power transmission winding L1, the series capacitor C1, and the series inductor Ls1 to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1. The common-mode current flows in the same direction as the above path or in the opposite direction.

[0092] 16 shows a common mode equivalent circuit 80 for the common mode current i c and the C / D rectifier circuit 74. The common mode equivalent circuit 80 includes a common mode winding Lcom, a common mode series capacitor Cscom, a common mode parallel capacitor Cpcom, and a common mode inductor Lscom.

[0093] One end of the common-mode winding Lcom is connected to one end of the common-mode series capacitor Cscom. The other end of the common-mode series capacitor Cscom is connected to one end of the common-mode inductor Lscom. The other end of the common-mode inductor Lscom is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 and the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2. The other end of the common-mode winding Lcom is connected to the junction of the first smoothing capacitor Cm1 and the second smoothing capacitor Cm2 of the capacitor bridge CB via the reference conductor G. The common-mode parallel capacitor Cpcom is connected between the junction of the common-mode series capacitor Cscom and the common-mode inductor Lscom and the reference conductor G.

[0094] 17 shows the path along which the differential mode current id flows. The differential mode current id flows from the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2, through the series inductor Ls4 and the series capacitor C4, to the reference end of the power transmission winding L4. The differential mode current id further flows through the power transmission windings L2, L3, and L1, the series capacitor C1, and the series inductor Ls1, to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1. The differential mode current id may flow in the same direction as the above-described path or in the opposite direction.

[0095] 18 shows a differential mode equivalent circuit 82 for the differential mode current id and the C / D rectifier circuit 74. The differential mode equivalent circuit 82 includes a differential mode winding Ldif, a differential mode series capacitor Csdif, a differential mode parallel capacitor Cpdif, and a differential mode inductor Lsdif.

[0096] One end of the differential-mode winding Ldif is connected to one end of the differential-mode series capacitor Csdif. The other end of the differential-mode series capacitor Csdif is connected to one end of the differential-mode inductor Lsdif. The other end of the differential-mode inductor Lsdif is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1. The other end of the differential-mode winding Ldif is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 via the reference conductor H. The differential-mode parallel capacitor Cpdif is connected between the junction of the differential-mode series capacitor Csdif and the differential-mode inductor Lsdif and the reference conductor H.

[0097] The upper part of FIG. 19 shows the common-mode current i c versus the position of the on-board coil 44. The middle part of FIG. 19 shows the differential-mode current i d versus the position of the on-board coil 44, and the lower part of FIG. 19 shows the received power Pr versus the position of the on-board coil 44. The horizontal axis represents the position of the on-board coil 44 relative to the position of the upstream wireless transmission winding 16, and the vertical axis represents the values ​​of the common-mode current i c, the differential-mode current i d, and the received power Pr. The position of the on-board coil 44 is represented by a normalized distance, where the position where the power transmission windings L2 and L3 face the upstream wireless transmission winding 16 is set to 0, and the distance between the center points of the power transmission windings L1 to L4 is set to 1. That is, the position of the on-board coil 44 shown in chart (a) of FIG. 14 is 0. The position of the on-board coil 44 shown in chart (b) of FIG. 14 is 1.5, and the position of the on-board coil 44 shown in chart (c) of FIG. 13 is 3.

[0098] As shown in the upper and middle sections of Figure 19, the common mode current i c and the differential mode current i d are shifted in period by a normalized distance of 1.5. When the magnitude of the common mode current i c is at a maximum, the magnitude of the differential mode current i d is at a minimum, and when the magnitude of the common mode current i c is at a minimum, the magnitude of the differential mode current i d is at a maximum.

[0099] As shown in the lower part of Figure 19, received power Pr reaches a maximum when the common-mode current iC reaches a maximum and when the differential-mode current iD reaches a maximum. When the common-mode current iC reaches a maximum, common-mode power transmission becomes dominant in power transmission from the power transmission device 12 to the C / D in-vehicle power conversion device 70. When the differential-mode current iD reaches a maximum, differential-mode power transmission becomes dominant. As the electric vehicle 24 travels along the road, the common mode and differential mode alternate as the dominant modes of power transmission. This prevents the received power from reaching a minimum value of 0 or close to 0 when the electric vehicle 24 travels along the road, thereby suppressing fluctuations in the received power associated with the travel of the electric vehicle 24.

[0100] Furthermore, the common mode equivalent circuit 80 shown in Fig. 16 and the differential mode equivalent circuit 82 shown in Fig. 18 both constitute an LCC resonant circuit. The LCC resonant circuit, through its impedance conversion function, suppresses changes in the load impedance on the power transmission side due to changes in the state of charge of the battery 36. Furthermore, when a load device is connected in parallel to the battery 36 or when a load device is connected in place of the battery 36, changes in the load impedance on the power transmission side due to changes in the impedance of the load device are suppressed. This facilitates control of the power transmitted from the power transmission device 12 to the C / D in-vehicle power conversion device 70.

[0101] FIG. 20 shows a circuit diagram of a C / D vehicle power converter 84 according to a fourth application example. The C / D vehicle power converter 84 is configured by replacing the C / D resonant circuit 72 in the C / D vehicle power converter 70 shown in FIG. 11 with series resonant capacitors Cs1, Cs0, and Cs4. The series resonant capacitor Cs1 is connected between the reference end of the power transmission winding L1 and the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1. The series resonant capacitor Cs0 is connected between the reference ends of the power transmission windings L2 and L3 and the junction of the first smoothing capacitor Cm1 and the second smoothing capacitor Cm2 of the capacitor bridge CB. The series resonant capacitor Cs4 is connected between the reference end of the power transmission winding L4 and the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2.

[0102] Fig. 21 shows a circuit diagram of a C / D in-vehicle power conversion device 86 according to the fifth application example. The C / D in-vehicle power conversion device 86 is obtained by removing the power transmission winding L4 from the C / D in-vehicle power conversion device 84 shown in Fig. 20 and shorting the location where the power transmission winding L4 was provided.

[0103] 22 shows a circuit diagram of a C / D in-vehicle power converter 88 according to the sixth application example. The C / D in-vehicle power converter 88 is the same as the C / D in-vehicle power converter 84 according to the fourth application example, except that a filter circuit 90 is provided between the series resonant capacitors Cs1, Cs0, and Cs4 and the C / D rectifier circuit 74.

[0104] The filter circuit 90 includes a series resonant circuit SR1 provided on a first path 92-1 from the series resonant capacitor Cs1 to the half rectifier bridge HD1 of the C / D rectifier circuit 74, a series resonant circuit SR0 provided on a zeroth path 92-0 from the series resonant capacitor Cs0 to the capacitor bridge CB of the C / D rectifier circuit 74, and a series resonant circuit SR4 provided on a fourth path 92-4 from the series resonant capacitor Cs4 to the half rectifier bridge HD2 of the C / D rectifier circuit 74. Each of the series resonant circuits SR1, SR0, and SR4 is formed by connecting an inductor and a capacitor in series.

[0105] The filter circuit 90 further includes a parallel resonant circuit PR10 provided between the first path 92-1 and the zeroth path 92-0, and a parallel resonant circuit PR40 provided between the fourth path 92-4 and the zeroth path 92-0. Each of the parallel resonant circuits PR10 and PR40 is formed by connecting an inductor and a capacitor in parallel. However, each parallel resonant circuit is provided between each of the series resonant capacitors Cs1, Cs0, and Cs4 and the series resonant circuits SR1, SR0, and SR4.

[0106] Any of the series resonant circuits SR1, SR0, and SR4 and the parallel resonant circuits PR10 and PR40 may be omitted. Furthermore, the element constants of the inductors and capacitors included in each series resonant circuit and each parallel resonant circuit may be determined according to the switching frequency of the power transfer device 12.

[0107] According to the filter circuit 90, the noise current flowing through the power transmission windings L1 to L4 is suppressed based on the nonlinearity of the diodes provided in the C / D rectifier circuit 74, and the noise electromagnetic waves emitted from the power transmission windings L1 to L4 are suppressed.

[0108] In the above embodiment, a plurality of wireless transmission windings 16 are arranged along a road. The plurality of wireless transmission windings 16 may also be arranged in a parking lot or the like. By arranging a plurality of wireless transmission windings within a parking space, power can be reliably transmitted to the battery of the electric vehicle even if there is variation in the parking positions of the electric vehicle.

[0109] 23 shows the configuration of a vehicle power transmission system 104 according to the third embodiment. In the vehicle power transmission system 104, the first rectifier circuit 32 and the second rectifier circuit 34 in the vehicle power transmission system 100 are replaced with a first power conversion circuit 32W and a second power conversion circuit 34W, respectively. To distinguish it from the on-board power conversion device 18 in the vehicle power transmission system 100, the on-board power conversion device is designated by the symbol "18W."

[0110] The first power conversion circuit 32W and the second power conversion circuit 34W each include a first half-switching bridge HB1 and a second half-switching bridge HB2 as two half-bridges connected in parallel. The first power conversion circuit 32W is obtained by replacing the half rectifier bridges HD1 and HD2 in the first rectifier circuit 32 shown in FIG. 1 with the first half-switching bridge HB1 and the second half-switching bridge HB2, respectively. The first half-switching bridge HB1 includes switching elements W1 and W2 connected in series. The second half-switching bridge HB2 includes switching elements W3 and W4 connected in series. The switching elements W1 to W4 may be semiconductor elements such as MOSFETs or IGBTs.

[0111] A diode is connected in parallel to each of the switching elements W1 and W3 with its anode facing the connection point with the switching elements W2 and W4, respectively. A diode is connected in parallel to each of the switching elements W2 and W4 with its cathode facing the connection point with the switching elements W1 and W3, respectively.

[0112] In the power transmission windings L1 to L4, one end of one of two adjacent power transmission windings is connected to the other end of the other, and the other end of one of the two adjacent power transmission windings and one end of the other are connected to the first power conversion circuit 32W or the second power conversion circuit 34W via a resonant path that forms a resonant circuit. The first power conversion circuit 32W and the second power conversion circuit 34W are converters that perform bidirectional AC-DC conversion between the resonant path and the outside. In the embodiment shown in FIGS. 1 to 3 , the resonant path is made up of resonant capacitors Cs, Ct, Cu, and Cv that form a resonant circuit together with the power transmission windings L1 to L4.

[0113] When switching is stopped, the first power conversion circuit 32W and the second power conversion circuit 34W have the same functions as the first rectifier circuit 32 and the second rectifier circuit 34. In this case, similar to the vehicle power transmission system 100 shown in Fig. 1, power is transmitted from the DC voltage source 30 in the power transmission device 12 to the battery 36 in the on-board power conversion device 18W. If a load device is connected to the on-board power conversion device 18W, power is transmitted to the load device.

[0114] 23, a diode is connected in parallel to each of the switching elements S1 and S3 in the power transmission device 12, with the anode facing the connection point with the switching elements S2 and S4, respectively. A diode is connected to each of the switching elements S2 and S4, with the cathode facing the connection point with the switching elements S1 and S3, respectively.

[0115] Therefore, when switching is stopped, the first half-switching bridge B1 and the second half-switching bridge B2 in the power transmission device 12 function as rectifier circuits. By switching the switching elements W1 to W4 in the first power conversion circuit 32W and the second power conversion circuit 34W in the same manner as the switching elements S1 to S4 in the power transmission device 12, power is transmitted from the battery 36 in the on-board power conversion device 18W or a load device connected to the on-board power conversion device 18W to the DC voltage source 30 in the power transmission device 12.

[0116] In the first to third application examples (FIGS. 8 to 10) of the first embodiment, the second embodiment (FIG. 11), and the fourth to sixth application examples (FIGS. 20 to 22) of the second embodiment, the first diode D1 and the second diode D2 may be replaced with switching elements. As in FIG. 23, a diode is connected in parallel to each switching element with a polarity that causes a current to flow in the opposite direction to the current flowing through the switching element. FIG. 24 shows a configuration in which the first diode D1 and the second diode D2 of the C / D vehicle power conversion device 70 of the second embodiment are replaced with switching elements. The first diode D1 and the second diode D2 in the half rectifier bridge HD1 are replaced with switching elements W1 and W2, respectively, and the first diode D1 and the second diode D2 in the half rectifier bridge HD2 are replaced with switching elements W3 and W4, respectively.

[0117] The winding directions of the power transmission windings L1 to L4 of the on-board coil 40 shown in Fig. 2 may be reversed. Fig. 25 shows an on-board coil 40R in which the reference end and the dependent end are interchanged with respect to the connection terminals s, t, u, and v, and the winding direction is clockwise. In the on-board coil 40R shown in Fig. 25, the dependent end of the power transmission winding L1 is connected to the connection terminal s, and the reference end of the power transmission winding L2 is connected to the connection terminal t. Furthermore, the dependent end of the power transmission winding L3 is connected to the connection terminal u, and the reference end of the power transmission winding L4 is connected to the connection terminal v.

[0118] 26 shows the configuration of a vehicle power transmission system 104 in which an on-board coil 40R is used instead of the on-board coil 40. In this configuration, the reference terminal and the dependent terminal of each of the power transmission windings L1 to L4 shown in FIG.

[0119] The winding directions of the power transmission windings L1 to L4 of the on-board coil 44 shown in Fig. 12 may also be reversed. Fig. 27 shows an on-board coil 44R in which the reference ends and dependent ends are interchanged with respect to the connection terminals s, t, u, and v, and the winding direction is clockwise. In the on-board coil 44R shown in Fig. 27, the dependent ends of the power transmission windings L1 to L4 are connected to the connection terminals s, t, u, and v, respectively.

[0120] 28 shows the configuration of a C / D in-vehicle power conversion device 70 that uses the in-vehicle coil 44R. In this configuration, the reference terminals and dependent terminals of the power transmission windings L1 to L4 in the C / D in-vehicle power conversion device 70 shown in FIG. 15 are interchanged, and the half rectifier bridges HD1 and HD2 are replaced with a first half switching bridge HB1 and a second half switching bridge HB2, respectively.

[0121] In the above-described first embodiment (FIG. 1), the first to third application examples of the first embodiment (FIGS. 8 to 10), the second embodiment (FIG. 11), and the fourth to sixth application examples of the second embodiment (FIGS. 20 to 22), the winding directions of the power transmission windings may also be opposite.

[0122] In the above embodiment, the power transmission windings L1 to L4 are arranged so that adjacent ones do not overlap. However, adjacent ones of the power transmission windings L1 to L4 may overlap. In this case, depending on the degree of overlap, it is possible to obtain the effect of suppressing fluctuations in received power according to the positional relationship between the wireless transmission winding 16 and the power transmission windings L1 to L4.

[0123] FIG. 2 shows a structure in which the adjacent power transmission windings L1 to L4 have the same winding direction. The winding directions of the power transmission windings L1 to L4 may be opposite to each other, as shown in FIG. 29 . Also, as shown in FIG. 29 , the dependent end of the power transmission winding L1, the reference end of the power transmission winding L2, the dependent end of the power transmission winding L3, and the reference end of the power transmission winding L4 may be commonly connected via resonant capacitors Cα1, Cα2, Cα3, and Cα4, respectively, which serve as resonant elements. The resonant capacitor Cα1 forms a resonant circuit together with the power transmission winding L1 and the resonant capacitor Cs. The resonant capacitor Cα2 forms a resonant circuit together with the power transmission winding L2 and the resonant capacitor Ct. The resonant capacitor Cα3 forms a resonant circuit together with the power transmission winding L3 and the resonant capacitor Cu. The resonant capacitor Cα4 forms a resonant circuit together with the power transmission winding L4 and the resonant capacitor Cv.

[0124] Fig. 30 shows an on-board power conversion device 18A that uses the power transmission windings L1 to L4 (on-board coil 40A) shown in Fig. 29. In the on-board power conversion device 18A, the polarities of the terminals of the power transmission windings L1 to L4 connected to the resonant capacitors Cs, Ct, Cu, and Cv are opposite to those of the on-board power conversion device 18 shown in Fig. 26.

[0125] The power transmission windings L1 to L4 shown in Fig. 29 may have the reversed winding direction, as shown in Fig. 31. Fig. 32 shows an on-board power conversion device 18B that uses the power transmission windings L1 to L4 (on-board coil 40B) shown in Fig. 31. In the on-board power conversion device 18B, the polarities of the terminals of the power transmission windings L1 to L4 connected to the connection terminals s, t, u, and v are reversed compared to the on-board power conversion device 18A shown in Fig. 30.

[0126] In the power transmission windings L1 to L4 shown in FIG. 2, one end of each winding is directly connected for each pair of windings that connect two of them, whereas in the power transmission windings L1 to L4 shown in FIGS. 29 and 31, one end of each winding is connected via a resonant capacitor for each pair of windings that connect two of them.

[0127] 33 shows a modified configuration of the power transmission windings L1 to L4 shown in FIG. 12, in which two power transmission windings that are connected across one adjacent power transmission winding are connected via two resonant capacitors. One end of resonant capacitor Cα1 is connected to the subordinate end of power transmission winding L1, and one end of resonant capacitor Cα3 is connected to the subordinate end of power transmission winding L3. The other end of resonant capacitor Cα1 and the other end of resonant capacitor Cα3 are connected in common. One end of resonant capacitor Cα2 is connected to the subordinate end of power transmission winding L2, and one end of resonant capacitor Cα4 is connected to the subordinate end of power transmission winding L4. The other end of resonant capacitor Cα2 and the other end of resonant capacitor Cα4 are connected in common. Resonant capacitors Cα1 to Cα4, together with power transmission windings L1 to L4 and a C / D resonance circuit 72, form a resonant circuit.

[0128] Fig. 34 shows a C / D in-vehicle power converter 70A that uses the power transmission windings L1 to L4 (in-vehicle coil 44A) shown in Fig. 33. In the C / D in-vehicle power converter 70A, the polarities of the terminals of the power transmission windings L1 to L4 connected to the connection terminals s, t, u, and v are opposite to those of the C / D in-vehicle power converter 70 shown in Fig. 28.

[0129] The winding directions of the power transmission windings L1 to L4 shown in Fig. 33 may be reversed, as shown in Fig. 35. Fig. 36 shows a C / D in-vehicle power converter 70B that uses the power transmission windings L1 to L4 (in-vehicle coil 44B) shown in Fig. 35. In the C / D in-vehicle power converter 70B, the polarities of the power transmission windings L1 to L4 connected to the connection terminals s, t, u, and v are reversed compared to the C / D in-vehicle power converter 70A shown in Fig. 34.

[0130] In the power transmission windings L1 to L4 shown in Fig. 12, one end of each winding is connected directly to a pair of windings that connect two of them, whereas in the power transmission windings L1 to L4 shown in Fig. 33 and 35, one end of each winding is connected via a resonant capacitor to a pair of windings that connect two of them. More specifically, in the power transmission windings L1 to L4 shown in Fig. 12, one end of one winding is directly connected to one end of another winding across an adjacent winding, whereas in the power transmission windings L1 to L4 shown in Fig. 33 and 35, one end of one winding is connected via a resonant capacitor to one end of another winding across an adjacent winding.

[0131] 1, at least one of the pair of power transmission windings L1 and L2, the pair of power transmission windings L2 and L3, the pair of power transmission windings L3 and L4, and the pair of power transmission windings L1 and L4 may be coupled. In this case, the resonant frequency when wireless power transfer is performed in the vehicle power transfer system 100 may no longer be an ideal frequency, and the transmitted power may increase or decrease. Therefore, the following modified form may be considered.

[0132] Figure 37 shows a circuit diagram of an on-board power conversion device 18C that is a modification of the on-board power conversion device 18 shown in Figure 1. The symbols in parentheses in Figure 37 represent capacitances. The on-board power conversion device 18C is configured by providing resonant capacitors Cd12, Cd23, Cd34, and Cd14 in place of the resonant capacitors Cs and Ct provided between the power transmission windings L1 and L2 and the first rectifier circuit 32, respectively, and the resonant capacitors Cu and Cv provided between the power transmission windings L3 and L4 and the second rectifier circuit 34, respectively, in the on-board power conversion device 18.

[0133] The resonant capacitor Cd12 is provided between an end of the power transmission winding L1 opposite the first rectifier circuit 32 and an end of the power transmission winding L2 opposite the first rectifier circuit 32. The resonant capacitor Cd23 is provided between an end of the power transmission winding L2 opposite the first rectifier circuit 32 and an end of the power transmission winding L3 opposite the second rectifier circuit 34. The resonant capacitor Cd34 is provided between an end of the power transmission winding L3 opposite the second rectifier circuit 34 and an end of the power transmission winding L4 opposite the second rectifier circuit 34. The resonant capacitor Cd14 is provided between an end of the power transmission winding L1 opposite the first rectifier circuit 32 and an end of the power transmission winding L4 opposite the second rectifier circuit 34.

[0134] In this way, the resonant capacitors Cd12, Cd23, Cd34, and Cd14 as resonant elements are delta-connected to one end of each of the power transmission windings L1 to L4 to form a delta-connected resonant capacitor circuit. Here, delta connection refers to a circuit configuration in which two adjacent terminals are connected by a circuit element so as to circle multiple terminals on the circuit diagram.

[0135] The capacitance of the resonant capacitor Cd12 is equal to that of the resonant capacitor Cd34 (C ｄａ The capacitance C of each of the resonant capacitors Cd12 and Cd34 ｄａ , the capacitance C of the resonant capacitor Cd23 ｄｂ , and the capacitance C of the resonant capacitor Cd14 ｄｃ are set to the values ​​expressed by the following (Equation 1) to (Equation 3), respectively.

[0136]

[0137] However, the capacitance C ｄａ , C ｄｂ and C ｄｃ This resonance condition is met when L is equal or approximately equal. １ ~L ４are the self-inductances of the power transmission windings L1 to L4, respectively. ω is the resonant angular frequency, and the capacitance C ｄａ , C ｄｂ and C ｄｃ The resonant frequency is the value obtained by dividing the resonant angular frequency by 2π. M １２ is the mutual inductance of the power transmission windings L1 and L2. ２３ is the mutual inductance of the power transmission windings L2 and L3. １４ is the mutual inductance of the power transmission windings L1 and L4. Although not shown in (Equation 1) to (Equation 3), the mutual inductance M ３４ is the mutual inductance M of the power transmission windings L1 and L2 １２ In a vehicle power transmission system using the on-board power conversion device 18C, contactless power feeding is performed at a resonant frequency of ω / (2π). The resonant frequency is the value obtained by dividing the equation obtained by solving any one of (Equation 1) to (Equation 3) for ω by 2π.

[0138] According to the on-board power conversion device 18C, even if at least one of the pair of power transmission windings L1 and L2, the pair of power transmission windings L2 and L3, the pair of power transmission windings L3 and L4, and the pair of power transmission windings L1 and L4 is coupled, a single resonant frequency is determined by the power transmission windings L1 to L4 and the resonant capacitors Cd12, Cd23, Cd34, and Cd14 that are delta-connected to one end of each of the power transmission windings L1 to L4.

[0139] This is the three mutual inductances M １２ , M ２３ and M １４ For three capacitances C ｄａ , C ｄｂ , and C ｄｃ This is because the resonant frequency can be set to one by adjusting the resonant frequency. Setting the resonant frequency to one can compensate for an increase or decrease in the transmitted power due to coupling of the power transmission windings, for example, for the transmitted power using the power transmission device 12, the wireless transmission circuit 20, and the on-board power conversion device 18C.

[0140] The first rectifier circuit 32 and the second rectifier circuit 34 shown in FIG. 37 may be replaced with the first power conversion circuit 32W and the second power conversion circuit 34W shown in FIG. 23, respectively.

[0141] 37, resonant capacitors Cd12, Cd23, Cd34, and Cd14 are delta-connected to the dependent end of power transmission winding L1, the reference end of power transmission winding L2, the dependent end of power transmission winding L3, and the reference end of power transmission winding L4. A first rectifier circuit 32 is connected to the reference end of power transmission winding L1 and the dependent end of power transmission winding L2, and a second rectifier circuit 32 is connected to the reference end of power transmission winding L3 and the dependent end of power transmission winding L4.

[0142] The on-board power conversion device 18C may be modified to a configuration in which resonant capacitors Cd12, Cd23, Cd34, and Cd14 are delta-connected to the reference end of power transmission winding L1, the dependent end of power transmission winding L2, the reference end of power transmission winding L3, and the dependent end of power transmission winding L4. In this case, a first rectifier circuit 32 is connected to the dependent end of power transmission winding L1 and the reference end of power transmission winding L2, and a second rectifier circuit 32 is connected to the dependent end of power transmission winding L3 and the reference end of power transmission winding L4. Even in this case, the first rectifier circuit 32 and the second rectifier circuit 34 may be replaced with a first power conversion circuit 32W and a second power conversion circuit 34W, respectively, as shown in FIG.

[0143] In the on-vehicle power conversion device 18C shown in FIG. 37, the capacitance C ｄａ , C ｄｂ and C ｄｃ The condition that the mutual inductance M of the power transmission windings L3 and L4 is equal to ３４ is the mutual inductance M of the power transmission windings L1 and L2. １２ Even if these conditions are not met, if they are met approximately, the increase or decrease in the transmitted power due to the coupling of the power transmission windings is compensated. However, the capacitance C ｄａ , C ｄｂ and C ｄｃ If any of the mutual inductances M ３４is the mutual inductance M of the power transmission windings L1 and L2. １２ If the difference is different from the above, the effect of compensating for the increase or decrease in transmission power may not be sufficient. Therefore, the following modified form is conceivable.

[0144] Figure 38 shows a circuit diagram of an on-board power conversion device 18D, which is a modification of the on-board power conversion device 18C shown in Figure 37. The symbols in parentheses in Figure 37 represent capacitances. In the on-board power conversion device 18D, resonant capacitors Cd1 to Cd4 are provided between the delta-connected resonant capacitors Cd12, Cd23, Cd34, and Cd14 and the power transmission windings L1 to L4.

[0145] One end of the resonant capacitor Cd1 is connected to the connection point between the resonant capacitors Cd12 and Cd14, and the other end of the resonant capacitor Cd1 is connected to one end of the power transmission winding L1. One end of the resonant capacitor Cd2 is connected to the connection point between the resonant capacitors Cd12 and Cd23, and the other end of the resonant capacitor Cd2 is connected to one end of the power transmission winding L2. One end of the resonant capacitor Cd3 is connected to the connection point between the resonant capacitors Cd23 and Cd34, and the other end of the resonant capacitor Cd3 is connected to one end of the power transmission winding L3. One end of the resonant capacitor Cd4 is connected to the connection point between the resonant capacitors Cd34 and Cd14, and the other end of the resonant capacitor Cd4 is connected to one end of the power transmission winding L4.

[0146] The other end of the power transmission winding L1 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the first rectifier circuit 32. The other end of the power transmission winding L2 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the first rectifier circuit 32. The other end of the power transmission winding L3 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD1 of the second rectifier circuit 34. The other end of the power transmission winding L4 is connected to the junction of the first diode D1 and the second diode D2 of the half rectifier bridge HD2 of the second rectifier circuit 34.

[0147] The capacitance of the resonant capacitor Cd1 is equal to the capacitance of the resonant capacitor Cd4 (C ｄｄ ). The capacitance of the resonant capacitor Cd2 is equal to the capacitance of the resonant capacitor Cd3 (C ｄｅ ).

[0148] The capacitance C of each of the resonant capacitors Cd1 and Cd4 ｄｄ and the capacitance C of the resonant capacitors Cd2 and Cd3 ｄｅ are set to the values ​​expressed by the following (Equation 4) and (Equation 5), respectively.

[0149]

[0150] In addition to (Equation 4) and (Equation 5), the above (Equation 1) to (Equation 3) may also be established.

[0151] According to the in-vehicle power conversion device 18D, the capacitance C ｄａ , C ｄｂ and C ｄｃ When either of the mutual inductances M ３４ is the mutual inductance M of the power transmission windings L1 and L2. １２ Even if different from the capacitance C ｄｄ、 and the capacitance C of the resonant capacitors Cd2 and Cd3 ｄｅ By adjusting the , the increase or decrease in transmitted power due to coupling of the power transmission windings can be compensated for.

[0152] 38 shows an example in which the resonant capacitors Cd1 to Cd4 are connected in series closer to the delta-connected resonant capacitor group than the power transmission windings L1 to L4. The resonant capacitors Cd1 and Cd2 may be connected in series on the first rectifier circuit 32 side of the power transmission windings L1 and L2, respectively. Similarly, the resonant capacitors Cd3 and Cd4 may be connected in series on the second rectifier circuit 34 side of the power transmission windings L3 and L4, respectively.

[0153] Furthermore, the first rectifier circuit 32 and the second rectifier circuit 34 shown in FIG. 38 may be replaced with the first power conversion circuit 32W and the second power conversion circuit 34W shown in FIG. 23, respectively.

[0154] [Configurations of the present invention] Configuration 1: A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the windings being all connected in common, or a pair of two of the plurality of windings being connected directly or via a resonance element, the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside, or performs bidirectional AC-DC conversion between each of the windings and the outside, and power being transmitted via a path between each of the windings and the converter. 1. A power transmission winding comprising: a plurality of windings, each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of one of the adjacent windings being connected to the other end of the other adjacent winding directly or via a resonant element forming a resonant circuit, the other end of one of the adjacent windings and the other end of the other adjacent winding being connected via a resonant path forming the resonant circuit to a converter that performs unidirectional rectification from the resonant path toward the outside or performs bidirectional AC / DC conversion between the resonant path and the outside. 2. A power transmission winding comprising: a plurality of half rectifier bridges connected in parallel, each half rectifier bridge including two rectifier elements connected in series so that one current inflow terminal and the other current outflow terminal are connected, the half rectifier bridges being connected in parallel, and one end of each of the windings not connected to the other winding being connected to the resonant path leading to the series connection point of the corresponding half rectifier bridge.1. The power transmission winding according to claim 1, wherein the resonant path comprises: a first path extending from the other end of one of the two adjacent windings to the converter; and a second path extending from the other end of the two adjacent windings to the converter, the first path comprising: a series capacitor and a series inductor connected in series; and an interphase capacitor provided between a connection point of the series capacitor and the series inductor in the first path and a connection point of the series capacitor and the series inductor in the second path. 2. The power transmission winding according to claim 1, wherein the resonant path comprises: a first path extending from the other end of one of the two adjacent windings to the converter; and a series capacitor and a series inductor connected in series, the first path comprising: a first end of the first adjacent winding and a second end of the second adjacent winding; and an interphase capacitor provided between a connection point of the series capacitor and the series inductor in the first path and a connection point of the series capacitor and the series inductor in the second path. 3. The power transmission winding according to claim 1, wherein the resonant path comprises: a first path extending from the other end of the first adjacent winding to the converter; and a second path extending from the other end of the second adjacent winding to the converter, the first path comprising: a first end of the first adjacent winding and a second end of the second adjacent winding; Configuration 6: The power transmission winding according to claim 5, wherein the plurality of windings include a first winding to a fourth winding, and wherein a first resonant path extending from the other end of the first winding to the converter, a second resonant path extending from the other end of the second winding and the other end of the third winding to the converter, and a third resonant path extending from the other end of the fourth winding to the converter each include a series capacitor and a series inductor connected in series, and an interphase capacitor is provided between a connection point of the series capacitor and the series inductor in the first resonant path, a connection point of the series capacitor and the series inductor in the second resonant path, and a connection point of the series capacitor and the series inductor in the third resonant path.Configuration 7: The power transmission winding according to configuration 5, comprising a first winding to a fourth winding as the plurality of windings, wherein the converter comprises: two half rectifier bridges connected in parallel, each half rectifier bridge including two rectifier elements connected in series such that one current-inflow terminal is connected to the other current-outflow terminal; and a capacitor bridge connected in parallel to the two half rectifier bridges, the capacitor bridge including two capacitors connected in series; wherein the other end of the first winding is connected to a first resonant path leading to a series connection point in one of the half rectifier bridges, the other ends of the second winding and the third winding are connected to a second resonant path leading to a series connection point in the capacitor bridge, and the other end of the fourth winding is connected to a third resonant path leading to a series connection point in the other half rectifier bridge. Configuration 8: The power transmission winding according to configuration 7, wherein the first resonant path, the second resonant path, and the third resonant path each include a series capacitor and a series inductor connected in series, and an inter-phase capacitor is provided between a connection point of the series capacitor and the series inductor in the first resonant path, a connection point of the series capacitor and the series inductor in the second resonant path, and the series capacitor and the series inductor in the third resonant path.Configuration 9: A power conversion device comprising: the power transmission winding according to any one of configurations 1 to 8; and the converter.Configuration 10: A power transfer system comprising: the power conversion device according to configuration 9; and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds areas facing two areas surrounded by two adjacent windings. Configuration 11: A power transmission system comprising: the power transmission winding according to any one of configurations 1 to 10; and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds an area opposite two areas surrounded by two adjacent windings.Configuration 12: A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the windings being connected via a circuit including a plurality of delta-connected resonance elements, and the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside or performs bidirectional AC / DC conversion between each of the windings and the outside, and power being transmitted via a path between each of the windings and the converter.

[0155] 12 Power transmission device, 16 Wireless transmission winding, 18, 18A, 18B, 18C, 18D, 50, 54 Vehicle-mounted power conversion device, 20, 60 Wireless transmission circuit, 24 Electric vehicle, 30 DC voltage source, 32 First rectifier circuit, 34 Second rectifier circuit, 36 Battery, 40, 40A, 40B, 44, 44A, 44B Vehicle-mounted coil, 42 Conductor, 52 Three-phase rectifier circuit, 56 LCC resonant circuit, 57, 90 Filter circuit, 92-0 Zeroth path, 58-1, 92-1 First path, 58-2 Second path, 58-3 Third path, 58-4, 92-4 Fourth path, 70, 70A, 70B, 84, 86 Common / differential mode vehicle-mounted power conversion device (C / D vehicle-mounted power conversion device), 72 C / D resonance circuit, 74 C / D rectifier circuit, 80 common mode equivalent circuit, 82 differential mode equivalent circuit, 100, 102 vehicle power transmission system.

Claims

1. A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings arranged in a specific direction, one end of each of the windings all connected together, or a pair of two of the plurality of windings connected together being connected directly or via a resonant element, the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside, or performs bidirectional AC-DC conversion between each of the windings and the outside, and power is transmitted via a path between each of the windings and the converter.

2. A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the two adjacent windings being connected to the other end of the other winding directly or via a resonant element forming a resonant circuit, and the other end of each of the two adjacent windings and one end of the other winding being connected via a resonant path forming the resonant circuit to a converter that performs unidirectional rectification from the resonant path toward the outside, or performs bidirectional AC / DC conversion between the resonant path and the outside.

3. A power transmission winding as claimed in claim 2, wherein the converter comprises a plurality of half-bridges connected in parallel, each half-bridge including two rectifying elements connected in series so that one current-inflow terminal is connected to the other current-outflow terminal, and wherein one of the ends of each winding that is not connected to the other winding is connected to the resonant path leading to the series connection point of the corresponding half-bridge.

4. A power transmission winding as claimed in claim 2, wherein the resonant paths comprise: a first path extending from the other end of one of the two adjacent windings to the converter; and a second path extending from the other end of the two adjacent windings to the converter, each of which comprises a series capacitor and a series inductor connected in series; and an interphase capacitor provided between the connection point of the series capacitor and the series inductor in the first path and the connection point of the series capacitor and the series inductor in the second path.

5. A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of one winding being connected to one end of another winding directly or via a resonant element that forms a resonant circuit across an adjacent winding, and the other end of each winding being connected via a resonant path that forms the resonant circuit to a converter that performs unidirectional rectification from the resonant path toward the outside or performs bidirectional AC / DC conversion between the resonant path and the outside.

6. A power transmission winding as claimed in claim 5, comprising a first winding to a fourth winding as the plurality of windings, wherein a first resonant path extending from the other end of the first winding to the converter, a second resonant path extending from the other end of the second winding and the other end of the third winding to the converter, and a third resonant path extending from the other end of the fourth winding to the converter each comprise a series capacitor and a series inductor connected in series, and wherein interphase capacitors are provided between the connection point of the series capacitor and the series inductor in the first resonant path, the connection point of the series capacitor and the series inductor in the second resonant path, and the connection point of the series capacitor and the series inductor in the third resonant path.

7. A power transmission winding as claimed in claim 5, comprising a first winding to a fourth winding as the plurality of windings, wherein the converter comprises: two half bridges connected in parallel, each half bridge including two rectifying elements connected in series so that one current inflow terminal is connected to the other current outflow terminal; and a capacitor bridge connected in parallel to the two half bridges, the capacitor bridge including two capacitors connected in series; wherein the other end of the first winding is connected to a first resonant path leading to a series connection point in one of the half bridges, the other ends of the second winding and the third winding are connected to a second resonant path leading to a series connection point in the capacitor bridge, and the other end of the fourth winding is connected to a third resonant path leading to a series connection point in the other half bridge.

8. A power transmission winding as claimed in claim 7, wherein each of the first resonant path, the second resonant path and the third resonant path comprises a series capacitor and a series inductor connected in series, and interphase capacitors are provided between the connection point of the series capacitor and the series inductor in the first resonant path, the connection point of the series capacitor and the series inductor in the second resonant path, and the series capacitor and the series inductor in the third resonant path.

9. A power conversion device comprising: a power transmission winding according to any one of claims 1 to 8; and the converter.

10. A power transmission system comprising: the power conversion device according to claim 9; and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds an area opposite two areas surrounded by two adjacent windings.

11. A power transmission system comprising: a power transmission winding according to any one of claims 1 to 8; and a wireless transmission winding formed in a flat loop shape, the wireless transmission winding having a shape and size that surrounds an area opposite two areas surrounded by two adjacent windings.

12. A power transmission winding comprising a plurality of windings each formed in a flat loop shape, the plurality of windings being arranged in a specific direction, one end of each of the windings being connected via a circuit including a plurality of delta-connected resonance elements, and the other end of each of the windings being connected to a converter that performs unidirectional rectification from each of the windings toward the outside or performs bidirectional AC / DC conversion between each of the windings and the outside, and power being transmitted via a path between each of the windings and the converter.

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