JP6455798B2 - Coil unit - Google Patents

Description

  The present invention relates to a coil unit for transmitting power wirelessly.

  In recent years, in order to transmit electric power without mechanical contact such as a cable, wireless power transmission technology using electromagnetic induction action between a primary (power transmission) coil and a secondary (power reception) coil that have been opposed has attracted attention. Therefore, the use as a power supply device for charging a secondary battery mounted on an electric vehicle (EV) or a plug-in hybrid electric vehicle (PHEV) is expected to be expanded.

  However, when the wireless power transmission technology is applied to a charging device in a power electronics device such as an electric vehicle, a large current needs to flow through the coil because high power transmission is required. As a result, the strength of the leakage magnetic field formed on the substrate increases, which may cause electromagnetic interference that adversely affects surrounding electronic devices.

  On the other hand, Patent Document 1 includes a plurality of coils, a second resonance coil for performing electromagnetic resonance with a first resonance coil arranged oppositely, and the first coil of the plurality of coils. Is a coil that is arranged such that the generated magnetic field has an opposite phase with respect to the surface facing the first resonance coil, with respect to at least one of the plurality of coils different from the first coil Techniques have been proposed to reduce leakage electromagnetic fields by units.

JP 2011-23496 A

  By the way, in the technique disclosed in Patent Document 1, since the second resonance coil is constituted by a plurality of coils connected in series or in parallel, when a large current is passed through the coil, the second resonance coil flows through a connection portion between the plurality of coils. Even if the current is increased and the inductance of the connection portion is relatively small, the strength of the leakage magnetic field formed by the connection portion may be increased. However, in the technique disclosed in Patent Document 1, no consideration is given to a leakage magnetic field formed by a connection portion between a plurality of coils. When a large current is passed through the coil, it is caused by a portion other than the coil. There is a problem that an unintended leakage magnetic field is formed.

  Then, this invention is made | formed in view of the said subject, and it aims at providing the coil unit which can reduce the unnecessary leakage magnetic field resulting from parts other than the coil of a coil unit.

  A coil unit according to the present invention is a coil unit for performing wireless power transmission, and is coated with an insulator that electrically connects a plurality of coils that are spaced apart from each other and a plurality of coils. A connection line, and the connection line is characterized in that an electromagnetic shielding member is disposed around the connection line.

  According to the present invention, the connecting wire that electrically connects the plurality of coils is covered with the insulator, and the electromagnetic shielding member is further disposed around the connecting wire. Therefore, the electromagnetic shielding member suppresses leakage of the magnetic field generated around the connection line to the outside when a current flows through the connection line. As a result, it is possible to reduce unnecessary leakage magnetic fields caused by portions other than the coils of the coil unit.

  Preferably, a lead wire covered with an insulator for connecting a plurality of coils to an external device is further provided, and an electromagnetic shielding member is disposed around the lead wire. In this case, the magnetic field generated around the lead wire due to the current flowing through the lead wire is prevented from leaking to the outside by the electromagnetic shielding member. As a result, it is possible to further reduce unnecessary leakage magnetic fields caused by portions other than the coil of the coil unit.

  As described above, according to the present invention, it is possible to provide a coil unit that can reduce an unnecessary leakage magnetic field caused by a portion other than the coil of the coil unit.

It is a system configuration schematic diagram showing the electrical configuration of a wireless power transmission system to which the coil unit according to the first embodiment of the present invention is applied together with a load. It is a perspective view which shows the coil unit which concerns on 1st Embodiment of this invention with a receiving coil. It is sectional drawing which shows the coil unit which concerns on 1st Embodiment of this invention with a receiving coil. It is a system structure schematic diagram which shows the electrical structure of the wireless power transmission system with which the coil unit which concerns on 2nd Embodiment of this invention is applied with a load. It is a perspective view which shows the coil unit which concerns on 2nd Embodiment of this invention with a receiving coil. It is sectional drawing which shows the coil unit which concerns on 2nd Embodiment of this invention with a receiving coil.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

(First embodiment)
With reference to FIGS. 1-3, the structure of wireless power transmission system S1 to which the coil unit which concerns on 1st Embodiment of this invention is applied is demonstrated. The coil unit according to the present embodiment can also be applied as a power receiving coil unit of a wireless power transmission system. However, in the present description, the coil unit according to the present embodiment is applied as a power transmission coil unit of a wireless power transmission system. This will be described using the example. FIG. 1 is a system configuration schematic diagram showing an electrical configuration of a wireless power transmission system to which a coil unit according to a first embodiment of the present invention is applied together with a load. FIG. 2 is a perspective view showing the coil unit according to the first embodiment of the present invention together with the power receiving coil. FIG. 3 is a cross-sectional view showing the coil unit according to the first embodiment of the present invention together with the power receiving coil.

  As shown in FIG. 1, the wireless power transmission system S1 includes a power source PW, an inverter INV, a coil unit Ltu1, a power receiving coil Lr, and a rectifier circuit DB.

  The power source PW supplies DC power to an inverter INV described later. The power source PW is not particularly limited as long as it outputs DC power. A DC power source rectified and smoothed from a commercial AC power source, a secondary battery, a DC power source generated by photovoltaic power, or a switching power source device such as a switching converter, etc. Is mentioned.

  The inverter INV has a function of converting input DC power supplied from the power source PW into AC power. The inverter INV is composed of a switching circuit in which a plurality of switching elements are bridge-connected. Examples of the switching elements constituting the switching circuit include elements such as MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor) and IBGT (Insulated Gate Bipolar Transistor). The inverter INV converts input DC power supplied from the power source PW into AC power and supplies the AC power to a coil unit Ltu1 described later. A capacitor (not shown) for improving the power factor of the circuit may be inserted between the inverter INV and the coil unit Ltu1.

  The coil unit Ltu1 has a function of transmitting the power supplied from the inverter INV to a power receiving coil Lr described later. When the wireless power transmission system S1 according to the present embodiment is applied to a power supply facility for a vehicle such as an electric vehicle, the coil unit Ltu1 is disposed on the ground or in the ground together with the power source PW and the inverter INV. The specific configuration of the coil unit Ltu1 will be described later.

  The power receiving coil Lr has a function of receiving the power transmitted from the coil unit Ltu1. When the wireless power transmission system S1 according to the present embodiment is applied to a power supply facility for a vehicle such as an electric vehicle, the power receiving coil Lr is mounted on the lower portion of the vehicle. A specific configuration of the power receiving coil Lr will be described later.

  The rectifier circuit DB has a function of rectifying AC power received by the power receiving coil Lr into DC power. Examples of the rectifier circuit DB include a conversion circuit having a full-wave rectification function using a diode bridge and a power smoothing function using a capacitor and a three-terminal regulator. The DC power rectified by the rectifier circuit DB is output to the load R. Here, as the load R, when the wireless power transmission system S1 according to the present embodiment is applied to a power supply facility for a vehicle such as an electric vehicle, a secondary battery included in the vehicle may be used. When the wireless power transmission system S1 according to this embodiment is applied to a power supply facility for a vehicle such as an electric vehicle, the rectifier circuit DB is mounted on the vehicle.

  With such a configuration, the coil unit Ltu1 and the power receiving coil Lr face each other, thereby realizing a wireless power transmission system S1 in which power is transmitted wirelessly.

  Next, the configuration of the coil unit Ltu1 and the power receiving coil Lr according to the first embodiment of the present invention will be described in detail.

  The coil unit Ltu1 includes a plurality of coils Lt, a magnetic core Ct, a connection line La1, a plurality of lead lines Lb, and a plurality of insulating members I.

  The plurality of coils Lt includes a coil Lt1 and a coil Lt2 that are arranged apart from each other. As shown in FIG. 2, in the present embodiment, the coil Lt1 is a spiral coil in which the winding Wt1 is wound in a plane, and the coil Lt2 is a spiral coil in which the winding Wt2 is wound in a plane. It is. Here, the winding Wt1 and the winding Wt2 are each composed of an insulation coated conductor in which a conductor made of copper or aluminum is coated with an insulator, and the winding direction of the winding Wt1 and the winding of the winding Wt2 The turning directions are opposite to each other. The coils Lt1 and Lt2 configured in this way are juxtaposed on the same plane in a direction orthogonal to the facing direction of the coil unit Ltu1 and the power receiving coil Lr. The number of turns and the arrangement interval between the coils Lt1 and Lt2 are appropriately set based on the distance between the coil unit Ltu1 and the power receiving coil Lr, desired power transmission efficiency, and the like.

  As shown in FIG. 3, the magnetic core Ct <b> 1 has a substantially U-order shape, and a plate-like portion disposed along the opposite side of the plurality of coils Lt to the side facing the power receiving coil Lr, A protrusion extending from one end of the coil-shaped portion through the central axis of the coil Lt1 and extending in the direction of the power receiving coil Lr, and a protrusion extending from the other end of the plate-shaped portion through the central axis of the coil Lt2 and extending in the direction of the receiving coil Lr It consists of parts. The magnetic core Ct1 plays a role of increasing the inductance of the coils Lt1 and Lt2 and efficiently generating a magnetic flux for power transmission. Such a magnetic core Ct1 is preferably made of a magnetic material such as ferrite having a high relative permeability.

  The connection line La1 has a function of electrically connecting the plurality of coils Lt. Specifically, one end of the connection line La1 is connected to the outer peripheral end of the winding Wt1 of the coil Lt1, and the other end is connected to the outer peripheral end of the winding Wt2 of the coil Lt2. That is, the connection line La1 electrically connects the coil Lt1 and the coil Lt2 in series. The connection line La1 is composed of a wire Wa1 in which a conductor such as copper or aluminum is covered with an insulator. In the present embodiment, an electromagnetic shielding member Sa1 is disposed around the connection line La1. That is, the connection line La1 is provided in layers from the inside in the order of the conducting wire, the insulator, and the electromagnetic shielding member Sa1. The electromagnetic shielding member Sa1 is made of a conductor such as copper or aluminum. Thereby, when a current flows through the connection line La1, an induction current, an eddy current, or the like is generated in the electromagnetic shielding member Sa1, and the magnetic field formed by the connection line La1 is canceled. As a result, the formation of a leakage magnetic field around the connection line La1 is suppressed. Note that the wire Wa1 of the connection line La1 and the windings Wt1 and Wt2 of the coils Lt1 and Lt2 may be integrally configured with the same conductive wire covered with an insulator, or may be configured separately. When the wire Wa1 of the connection line La1 and the windings Wt1 and Wt2 of the coils Lt1 and Lt2 are formed of the same conductor covered with an insulator, the electromagnetic shielding member Sa1 is disposed only in the portion corresponding to the connection line La1. It only has to be.

  The plurality of lead lines Lb have a function of connecting the plurality of coils Lt and an external device. In the present embodiment, the coil Lt1 is constituted by a lead line Lb1 connecting the external device and the coil Lt2 and a lead wire Lb2 connecting the external device. Specifically, one end of the lead line Lb1 is connected to the inner peripheral side end of the winding Wt1 of the coil Lt1, and the other end is connected to the output terminal of the inverter INV. Similarly, one end of the lead line Lb2 is connected to the inner peripheral side end of the winding Wt2 of the coil Lt2, and the other end is connected to the output terminal of the inverter INV. That is, the lead lines Lb1 and Lb2 serve to electrically connect the coils Lt1 and Lt2 and the inverter INV. The lead wires Lb1 and Lb2 are respectively composed of wire rods Wb1 and Wb2 in which conductive wires such as copper and aluminum are covered with an insulator. In the present embodiment, the lead wires Lb1 and Lb2 are provided with electromagnetic shielding members Sb1 and Sb2 around them. In other words, the lead line Lb1 is provided in a layered order from the inside in the order of the conducting wire, the insulator, and the electromagnetic shielding member Sb1, and the lead line Lb2 is provided in a layered order in the order of the conducting wire, the insulator, and the electromagnetic shielding member Sb2. It becomes. The electromagnetic shielding members Sb1 and Sb2 are made of a conductor such as copper or aluminum. As a result, when a current flows through the lead lines Lb1 and Lb2, an induction current or an eddy current is generated in the electromagnetic shielding members Sb1 and Sb2, and the magnetic field formed by the lead lines Lb1 and Lb2 is canceled. As a result, the formation of a leakage magnetic field around the lead lines Lb1 and Lb2 is suppressed. The wires Wb1 and Wb2 of the lead wires Lb1 and Lb2 and the windings Wt1 and Wt2 of the coils Lt1 and Lt2 may be formed integrally with the same conductor covered with an insulator, or may be configured separately. Good. When the wire rods Wb1 and Wb2 of the lead wires Lb1 and Lb2 and the windings Wt1 and Wt2 of the coils Lt1 and Lt2 are made of the same conductive wire covered with an insulator, only the portions corresponding to the lead wires Lb1 and Lb2 are electromagnetically shielded. The members Sb1 and Sb2 may be disposed.

  The plurality of insulating members I are between the connecting line La1 and the magnetic core Ct1 and between the insulating member Ia1 disposed along the extending direction of the connecting line La1, the lead line Lb1, and the coil Lt1. An insulating member Ib1 disposed along the extending direction of the lead line Lb1, and an insulating member Ib2 disposed between the lead line Lb2 and the coil Lt and along the extending direction of the lead line Lb2. . The insulating member Ia1 plays a role of distinguishing the potential between the electromagnetic shielding member Sa1 and the magnetic core Ct1 of the connection line La1 and preventing discharge between the electromagnetic shielding member Sa1 and the magnetic core Ct1. Thereby, the magnetic field generated around the connection line La1 is canceled out by the induced current or eddy current of the electromagnetic shielding member Sa1, and is more reliably suppressed from leaking outside the electromagnetic shielding member Sa1. The insulating members Ib1 and Ib2 distinguish the potentials of the electromagnetic shielding members Sb1 and Sb2 of the lead lines Lb1 and Lb2 from the coils Lt1 and Lt2, and prevent discharge between the electromagnetic shielding members Sb1 and Sb2 and the coils Lt1 and Lt2. Play a role. As a result, the magnetic field generated around the lead lines Lb1 and Lb2 is canceled by the induced currents and eddy currents of the electromagnetic shielding members Sb1 and Sb2, and is more reliably suppressed from leaking to the outside of the electromagnetic shielding members Sb1 and Sb. The

  The power receiving coil Lr is a solenoid coil in which a winding Wr is spirally wound around a magnetic core Cr. The axial direction of the power receiving coil Lr is a direction orthogonal to the facing direction of the coil unit Ltu1 and the power receiving coil Lr, and is parallel to the arrangement direction of the plurality of coils Lt1 and Lt2 of the coil unit Ltu1. The winding Wr is made of an insulating coated conductor obtained by coating a conductive wire made of copper or aluminum with an insulator. The number of turns of the power receiving coil Lr is appropriately set based on the distance between the coil unit Ltu1 and the power receiving coil Lr, desired power transmission efficiency, and the like.

  Next, the principle of wireless power transmission and leakage magnetic field reduction in this embodiment will be described. When the coil unit Ltu1 is supplied with power from the inverter INV and a current flows through the coils Lt1 and Lt2, a magnetic field is formed around the coils Lt1 and Lt2. Here, since the winding direction of the winding Wt1 of the coil Lt1 and the winding direction of the winding Wt2 of the coil Lt2 are opposite to each other, the coils Lt1, Lt2 pass through the magnetic core Ct, and the coils Lt1, Lt2 Generates magnetic fluxes that link together. An electromotive force is generated in the power receiving coil Lr by the magnetic flux interlinking with the power receiving coil Lr. The electromotive force generated in the power receiving coil Lr is rectified by the rectifier circuit DB and supplied to the load R.

  At this time, in the coil unit Ltu1, a current also flows through the connection line La1 and the lead lines Lb1 and Lb2, and a magnetic field is also formed around the connection line La1 and the lead lines Lb1 and Lb2. However, since the magnetic flux generated by these magnetic fields circulates around the connection line La1 and the lead lines Lb1 and Lb2, it does not interlink with the power receiving coil Lr. That is, the magnetic field formed by the current flowing through the connection line La1 and the lead lines Lb1 and Lb2 is a leakage magnetic field that does not contribute to wireless power transmission. In the present embodiment, since the electromagnetic shielding member Sa1 is disposed around the connection line La1, when an electric current flows through the connection line La1, an induction current or an eddy current is generated in the electromagnetic shielding member Sa1, and the connection line La1. Cancels out the magnetic field formed. As a result, the formation of a leakage magnetic field around the connection line La1 is suppressed. In the present embodiment, since the electromagnetic shielding members Sb1 and Sb2 are disposed around the lead lines Lb1 and Lb2, when a current flows through the lead lines Lb1 and Lb2, the electromagnetic shielding members Sb1 and Sb2 An induced current or an eddy current is generated, and the magnetic field formed by the lead lines Lb1 and Lb2 is canceled. As a result, the formation of a leakage magnetic field around the lead lines Lb1 and Lb2 is suppressed.

  As described above, the coil unit Ltu1 according to the present embodiment includes the plurality of coils Lt and the connection line La1 that electrically connects the plurality of coils Lt, and the connection line La1 is surrounded by the electromagnetic shielding member Sa1. Is arranged. Therefore, the magnetic shielding member Sa1 suppresses leakage of the magnetic field generated around the connection line La1 when current flows through the connection line La1. As a result, it is possible to reduce unnecessary leakage magnetic fields caused by portions other than the coils Lt1 and Lt2 of the coil unit Ltu1.

  In addition, the coil unit Ltu1 according to the present embodiment further includes lead wires Lb1 and Lb2 coated with an insulator for connecting the plurality of coils Lt to an external device, and the lead wires Lb1 and Lb2 are electromagnetically shielded around the periphery. Members Sb1 and Sb2 are disposed. Therefore, the magnetic field generated around the lead lines Lb1 and Lb2 due to the current flowing through the lead lines Lb1 and Lb2 is prevented from leaking to the outside by the electromagnetic shielding members Sb1 and Sb2. As a result, it is possible to further reduce unnecessary leakage magnetic fields caused by portions other than the coils Lt1 and Lt2 of the coil unit Ltu1.

(Second Embodiment)
Next, with reference to FIGS. 4-6, the structure of wireless power transmission system S2 to which the coil unit which concerns on 2nd Embodiment of this invention is applied is demonstrated. The coil unit according to the present embodiment can also be applied as a power receiving coil unit of a wireless power transmission system. However, in the present description, the coil unit according to the present embodiment is applied as a power transmission coil unit of a wireless power transmission system. This will be described using the example. FIG. 4 is a system configuration schematic diagram showing an electrical configuration of a wireless power transmission system to which the coil unit according to the second embodiment of the present invention is applied together with a load. FIG. 5 is a perspective view showing a coil unit according to the second embodiment of the present invention together with a power receiving coil. FIG. 6 is a sectional view showing the coil unit according to the second embodiment of the present invention together with the power receiving coil.

  As illustrated in FIG. 4, the wireless power transmission system S2 includes a power source PW, an inverter INV, a coil unit Ltu2, a power receiving coil Lr, and a rectifier circuit DB. The configurations of the power source PW, the inverter INV, the power receiving coil Lr, and the rectifier circuit DB are the same as those of the wireless power transmission system S1 of the first embodiment. The present embodiment is different from the wireless power transmission system S1 of the first embodiment in that a coil unit Ltu2 is provided instead of the coil unit Ltu1 of the wireless power transmission system S1 of the first embodiment. The following description will focus on differences from the wireless power transmission system S1 of the first embodiment.

  The coil unit Ltu2 includes a plurality of coils Lt, a magnetic core Ct2, a plurality of connection lines La, a plurality of lead lines Lb, and a plurality of insulating members I.

  The plurality of coils Lt includes a coil Lt3, a coil Lt4, and a coil Lt5 that are spaced apart from each other. As shown in FIG. 5, in this embodiment, the coil Lt3 is a solenoid coil in which a winding Wt3 is spirally wound around a magnetic core Ct2 described later, and the coil Lt4 is wound around a magnetic core Ct2 described later. The wire Wt4 is a solenoid coil wound in a spiral shape, and the coil Lt5 is a solenoid coil in which a winding Wt5 is wound spirally around a magnetic core Ct2 described later. Here, the winding Wt3, the winding Wt4, and the winding Wt5 are each composed of an insulation-coated conductor in which a conductive wire made of copper or aluminum is coated with an insulator, and the winding direction and winding of the winding Wt3. The winding direction of the wire Wt4 is opposite to each other, and the winding direction of the winding Wt4 and the winding direction of the winding Wt5 are opposite to each other. That is, the winding direction of the winding Wt3 and the winding direction of the winding Wt5 are the same. The coil Lt3, the coil Lt4, and the coil Lt5 configured as described above are arranged in the order of the coil Lt3, the coil Lt4, and the coil Lt5 in the direction orthogonal to the facing direction of the coil unit Ltu2 and the power receiving coil Lr. The axial direction coincides with the axial direction of the coil Lt4 and the axial direction of the coil Lt5. The number of turns and the arrangement interval of the coils Lt3, Lt4, and Lt5 are appropriately set based on the distance between the coil unit Ltu2 and the power receiving coil Lr, desired power transmission efficiency, and the like.

  As shown in FIGS. 5 and 6, the magnetic core Ct2 has a substantially rectangular parallelepiped shape, and extends so as to penetrate the central axes of the coil Lt3, the coil Lt4, and the coil Lt5. That is, the longitudinal direction of the magnetic core Ct2 is a direction parallel to the axial direction of the power receiving coil Lr, and is a direction orthogonal to the facing direction of the coil unit Ltu2 and the power receiving coil Lr. The magnetic core Ct2 plays a role of increasing the inductance of the coils Lt3, Lt4, Lt5 and efficiently generating a magnetic flux for power transmission. Such a magnetic core Ct2 is preferably made of a magnetic material such as ferrite having a high relative permeability.

  The plurality of connection lines La have a function of electrically connecting the plurality of coils Lt. Specifically, one end is connected to one end of the winding Wt3 of the coil Lt3, the other end is connected to one end of the winding Wt4 of the coil Lt4, and one end of the coil Lt4. A connection line La3 connected to the other end of the winding Wt4 and having the other end connected to one end of the winding Wt5 of the coil Lt5. That is, the connection line La2 electrically connects the coil Lt3 and the coil Lt4 in series, and the connection line La3 electrically connects the coil Lt4 and the coil Lt5 in series. The connection line La2 is composed of a wire Wa2 in which a conductor such as copper or aluminum is covered with an insulator. In the present embodiment, the connection line La2 is provided with an electromagnetic shielding member Sa2 around it. That is, the connection line La2 is provided in layers from the inside in the order of the conducting wire, the insulator, and the electromagnetic shielding member Sa2. The electromagnetic shielding member Sa2 is made of a conductor such as copper or aluminum. Thereby, when a current flows through the connection line La2, an induced current, an eddy current, or the like is generated in the electromagnetic shielding member Sa2, and the magnetic field formed by the connection line La2 is canceled. As a result, the formation of a leakage magnetic field around the connection line La2 is suppressed. Similarly, the connection line La3 is composed of a wire material Wa3 in which a conductor such as copper or aluminum is covered with an insulator. In the present embodiment, the connection line La3 is provided with an electromagnetic shielding member Sa3 around it. That is, the connection line La3 is provided in layers in the order of the conducting wire, the insulator, and the electromagnetic shielding member Sa3 from the inside. The electromagnetic shielding member Sa3 is made of a conductor such as copper or aluminum. Thereby, when a current flows through the connection line La3, an induced current, an eddy current, or the like is generated in the electromagnetic shielding member Sa3, and the magnetic field formed by the connection line La3 is canceled. As a result, the formation of a leakage magnetic field around the connection line La3 is suppressed. Note that the wire rods Wa2 and Wa3 of the connection lines La2 and La3 and the windings Wt3, Wt4 and Wt5 of the coils Lt3, Lt4 and Lt5 may be configured integrally with the same conductor covered with an insulator, or separately. It may be configured. When the wire rods Wa2 and Wa3 of the connection lines La2 and La3 and the windings Wt3, Wt4 and Wt5 of the coils Lt3, Lt4 and Lt5 are formed of the same conductor covered with an insulator, a portion corresponding to the connection lines La2 and La3 The electromagnetic shielding members Sa2 and Sa3 may be disposed only on the surface.

  The plurality of lead lines Lb have a function of connecting the plurality of coils Lt and an external device. In the present embodiment, the lead wire Lb3 that connects the coil Lt3 and the external device and the lead wire Lb4 that connects the coil Lt5 and the external device are configured. Specifically, the lead line Lb3 has one end connected to the other end of the winding Wt3 of the coil Lt3 and the other end connected to the output terminal of the inverter INV. Similarly, the lead line Lb4 has one end connected to the other end of the winding Wt5 of the coil Lt5 and the other end connected to the output terminal of the inverter INV. That is, the lead lines Lb3, Lb4 serve to electrically connect the coils Lt3, Lt5 and the inverter INV. The lead wires Lb3 and Lb4 are made of wire rods Wb3 and Wb4, respectively, in which conductive wires such as copper and aluminum are covered with an insulator. In the present embodiment, the lead wires Lb3 and Lb4 are provided with electromagnetic shielding members Sb3 and Sb4 around them. In other words, the lead line Lb3 is provided in a layered order from the inside in the order of the conductor, the insulator, and the electromagnetic shielding member Sb3, and the lead line Lb4 is provided in a layered order in the order of the conductor, the insulator, and the electromagnetic shielding member Sb4 from the inside. It becomes. The electromagnetic shielding members Sb3 and Sb4 are made of a conductor such as copper or aluminum. Thereby, when a current flows through the lead lines Lb3 and Lb4, an induction current, an eddy current, and the like are generated in the electromagnetic shielding members Sb3 and Sb4, and the magnetic field formed by the lead lines Lb3 and Lb4 is canceled. As a result, the formation of a leakage magnetic field around the lead lines Lb3 and Lb4 is suppressed. Note that the wire rods Wb3, Wb4 of the lead wires Lb3, Lb4 and the windings Wt3, Wt4, Wt5 of the coils Lt3, Lt4, Lt5 may be formed integrally with the same conductor covered with an insulator, or separately. It may be configured. When the wire rods Wb3, Wb4 of the lead wires Lb3, Lb4 and the windings Wt3, Wt4, Wt5 of the coils Lt3, Lt4, Lt5 are made of the same conducting wire coated with an insulator, the portion corresponding to the lead wires Lb3, Lb4 The electromagnetic shielding members Sb3 and Sb4 may be disposed only on the surface.

  The plurality of insulating members I are between the connecting line La2 and the magnetic core Ct2, and between the connecting member La3 and the magnetic core Ct2 between the insulating member Ia2 disposed along the extending direction of the connecting line La2. An insulating member Ia3 disposed along the extending direction of the connecting line La2, an insulating member Ib3 disposed between the lead line Lb3 and the magnetic core Ct2 and along the extending direction of the lead line Lb3, And an insulating member Ib4 disposed between the lead line Lb4 and the magnetic core Ct2 along the extending direction of the lead line Lb4. The insulating members Ia2 and Ia3 play a role of distinguishing the potentials of the electromagnetic shielding members Sa2 and Sa3 and the magnetic core Ct2 of the connection lines La2 and La3 and preventing discharge between the electromagnetic shielding members Sa2 and Sa3 and the magnetic core Ct2. . As a result, the magnetic field generated around the connection lines La2 and La3 is canceled out by the induced currents and eddy currents of the electromagnetic shielding members Sa2 and Sa3, and the leakage to the outside of the electromagnetic shielding members Sa2 and Sa3 is more reliably suppressed. . The insulating members Ib3 and Ib4 distinguish the potentials of the electromagnetic shielding members Sb3 and Sb4 and the magnetic core Ct2 of the lead lines Lb33 and Lb4 and prevent the discharge between the electromagnetic shielding members Sb3 and Sb4 and the magnetic core Ct2. Fulfill. As a result, the magnetic field generated around the lead lines Lb3 and Lb4 is more reliably suppressed from being canceled by the induction current or eddy current of the electromagnetic shielding members Sb3 and Sb4 and leaking outside the electromagnetic shielding members Sb3 and S4. The

  Next, the principle of wireless power transmission and leakage magnetic field reduction in this embodiment will be described. When the coil unit Ltu2 is supplied with power from the inverter INV and a current flows through the coils Lt3, Lt4, and Lt5, a magnetic field is formed around the coils Lt3, Lt4, and Lt5. Here, the winding direction of the winding Wt3 of the coil Lt3 and the winding direction of the winding Wt4 of the coil Lt4 are opposite to each other, and the winding direction of the winding Wt5 of the coil Lt5 and the winding Wt4 of the coil Lt4 are reversed. Since the turning directions are opposite to each other, the magnetic field generated by the coil Lt3 and the coil Lt5 is opposite to the magnetic field generated by the coil Lt4. As a result, the coil Lt4 generates a magnetic flux that links the coil Lt4 while passing through the magnetic core Ct2. An electromotive force is generated in the power receiving coil Lr by the magnetic flux interlinking with the power receiving coil Lr. The electromotive force generated in the power receiving coil Lr is rectified by the rectifier circuit DB and supplied to the load R. A part of the magnetic field formed by the coil Lt3 and the coil Lt5 is formed at a position away from the coil Lt4 by the coil Lt4 by strengthening the magnetic field formed between the coil Lt4 and the power receiving coil Lr by the coil Lt4. Decrease the magnetic field. That is, the coil Lt3 and the coil Lt5 function as coils that reduce unnecessary leakage magnetic fields.

  At this time, in the coil unit Ltu2, a current also flows through the connection lines La2 and La3 and the lead lines Lb3 and Lb4, and a magnetic field is also formed around the connection lines La2 and La3 and the lead lines Lb3 and Lb4. However, the magnetic flux generated by these magnetic fields is a magnetic flux that circulates around the connection lines La2 and La3 and the lead lines Lb3 and Lb4. The connection lines La2 and La3 and the lead lines Lb3 and Lb4 are connected to the coils Lt3, Lt4, and Lt5. Since the direction is perpendicular to the windings Wt3, Wt4, and Wt5, the magnetic flux generated by the connection lines La2 and La3 and the lead lines Lb3 and Lb4 does not interlink with the power receiving coil Lr. That is, the magnetic field formed by the current flowing through the connection lines La2 and La3 and the lead lines Lb3 and Lb4 is a leakage magnetic field that does not contribute to wireless power transmission. In the present embodiment, since the electromagnetic shielding members Sa2 and Sa3 are disposed around the connection lines La2 and La3, when an electric current flows through the connection lines La2 and La3, an induced current or eddy current flows in the electromagnetic shielding members Sa2 and Sa3. An electric current or the like is generated, and the magnetic field formed by the connection lines La2 and La3 is canceled. As a result, the formation of a leakage magnetic field around the connection lines La2 and La3 is suppressed. Moreover, in this embodiment, since electromagnetic shielding member Sb3, Sb4 is arrange | positioned around leader line Lb3, Lb4, when an electric current flows into leader line Lb3, Lb4, electromagnetic shielding member Sb3, Sb4 is carried out. An induced current or an eddy current is generated, and the magnetic field formed by the lead lines Lb3 and Lb4 is canceled. As a result, the formation of a leakage magnetic field around the lead lines Lb3 and Lb4 is suppressed.

  As described above, the coil unit Ltu2 according to the present embodiment includes the plurality of coils Lt and the connection lines La2 and La3 that electrically connect the plurality of coils Lt to each other, and the connection lines La2 and La3 are arranged around the periphery. Electromagnetic shielding members Sa2 and Sa3 are provided. For this reason, the electromagnetic shielding members Sa2 and Sa3 suppress the leakage of the magnetic field generated around the connection lines La2 and La3 when current flows through the connection lines La2 and La3. As a result, it is possible to reduce unnecessary leakage magnetic fields caused by portions other than the coils Lt3, Lt4, and Lt5.

  The coil unit Ltu2 according to the present embodiment further includes lead wires Lb3 and Lb4 coated with an insulator for connecting the plurality of coils Lt to an external device, and the lead wires Lb3 and Lb4 are electromagnetically shielded around them. Members Sb3 and Sb4 are provided. Therefore, the magnetic field generated around the lead lines Lb3 and Lb4 due to the current flowing through the lead lines Lb3 and Lb4 is prevented from leaking to the outside by the electromagnetic shielding members Sb1 and Sb2. As a result, it is possible to further reduce unnecessary leakage magnetic fields caused by portions other than the coils Lt3, Lt4, and Lt5 of the coil unit Ltu2.

  The present invention has been described based on the embodiments. It will be understood by those skilled in the art that the embodiments are illustrative, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. By the way. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive.

  S1, S2 ... Wireless power transmission system, Ltu1, Ltu2 ... Coil unit, Ct1, Ct2 ... Magnetic core, Lt ... Multiple coils, Lt1-Lt5 ... Coil, Wt1-Wt5 ... Winding, La ... Multiple connection lines, La1 ~ La3 ... connection line, Lb ... multiple lead wires, Lb1-Lb4 ... lead wire, Wa1-Wa3, Wb1-Wb4 ... wire, Sa1-Sa3, Sb1-Sb4 ... electromagnetic shielding member, I ... multiple insulating members, Ia1 ~ Ia3, Ib1 ~ Ib4 ... insulating member, PW ... power source, INV ... inverter, Lr ... power receiving coil, Cr ... magnetic core, Wr ... winding, DB ... rectifier circuit, R ... load.

Claims (2)

A coil unit for performing wireless power transmission,
A plurality of coils spaced apart from each other;
A connection wire coated with an insulator for electrically connecting the plurality of coils, and
The connection unit has a coil unit in which an electromagnetic shielding member is disposed around the connection line. Further comprising a lead wire coated with an insulator for connecting the plurality of coils to an external device,
The coil unit according to claim 1, wherein an electromagnetic shielding member is disposed around the lead wire.

Images