JP2018166394A - Inductive power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductive power supply device excellent in serviceability.SOLUTION: Before starting power supply to a vehicle battery, a movable core 21 around which a vehicle coil (secondary coil) 22 is not wound is dropped onto a ground core 11 around which a ground coil (primary coil) 12 is wound. Hereby, a mutual inductance between the vehicle coil and the ground coil is improved greatly. A transmitter connected to the ground coil has a step-down chopper using magnetic energy accumulated in a leakage inductance of the ground coil. A receiver connected to the vehicle coil has a step-up chopper using magnetic energy accumulated in a leakage inductance of the vehicle coil. The receiver and the transmitter constitute an insulation-type one-way or two-way DCDC converter. The primary coil of the transmitter and the secondary coil of the receiver which constitute a transformer have respectively a leakage inductance operated as an inductor of the chopper.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inductive power supply apparatus, and more particularly to an inductive charging apparatus for an electric vehicle.

If a small battery is employed, the manufacturing cost and weight of the electric vehicle is reduced. This weight reduction extends the mileage of the electric vehicle. However, small batteries that require frequent charging require automation of charging operations. Thus, it is understood that known wireless charging technology that supplies electromagnetic energy from ground coils to vehicle coils through the air gap is potentially very important in electric vehicle technology.

Inductive power transfer (IPT) technology using a relatively low frequency such as 20 kHz improves electromagnetic noise problems and switching loss problems. However, in the conventional IPT technology, the effective air gap length and the effective horizontal misalignment length are very short. Patent Documents 1 and 2 filed by the present inventor propose an IPT technique for moving a vehicle coil wound around a vehicle core. However, heavy vehicle cores and vehicle coils require large lifting devices.

Conventional wireless charging technology employs a resonant circuit to improve power factor. However, the resonant current reciprocating between the leakage inductance and the capacitor causes power loss that is independent of effective power transfer from the ground coil to the vehicle coil. Further, the inductance values of the ground coil and the vehicle coil change due to environmental changes. Therefore, it is not easy to accurately realize each resonance of the ground coil and the vehicle coil.

JP 2010-22183 A JP 2011-152025 A

One object of the present invention is to provide an inductive power feeding device having excellent practicality. A more specific object of the present invention is to provide an induction power feeding device for an electric vehicle having excellent performance in terms of manufacturing cost, power transmission efficiency, horizontal misalignment margin, electromagnetic wave noise, and the like.

According to one aspect of the invention, only the movable core that is part of the vehicle core descends on the ground core for inductive feeding. As a result, an induction power feeding device having excellent characteristics can be realized.

Preferably, the vehicle core includes a fixed core fixed to the bottom of the vehicle and a movable core magnetically connected to the fixed core. The vehicle coil is wound around a fixed core. The movable core has a front arm and a rear arm that are vertically movable. The pivotable forearm contacts the front end of the fixed core. The pivotable rear arm contacts the rear end of the fixed core. A front plate extending in the width direction of the vehicle is supported by the front end portion of the front arm. A rear plate extending in the width direction of the vehicle is supported by the tip of the rear arm. The ground core has a central rod wound with a ground coil, a front rod extending forward from the central rod, and a rear rod extending rearward from the central rod. Thereby, a sufficient misalignment margin can be realized.

According to another aspect of the present invention, a transmitter for supplying power to the ground coil and a receiver for rectifying the power received from the vehicle coil are provided. This transmitter uses the ground coil leakage inductance as the step-down chopper inductor. This receiver uses the leakage inductance of the vehicle coil as an inductor for the boost chopper. As a result, an inductive power feeder having excellent power transmission efficiency is economically realized. Preferably, the secondary inductor and the vehicle coil connected in series are connected to the AC output terminal of the traction inverter through a diode. The secondary transistor that stores magnetic energy in the inductor of the step-up chopper is a lower arm transistor of a traction inverter. The output diode that outputs the magnetic energy stored in the inductor of the step-up chopper to the vehicle battery includes an anti-parallel diode of the upper arm transistor of the traction inverter. This reduces the manufacturing cost of the receiver.

The inductive power supply apparatus having a transmitter having a step-down chopper and a receiver having a step-up chopper operates in a non-resonant manner. This non-resonant type inductive power supply apparatus can be employed in applications other than electric vehicles. Since the receiver output voltage is essentially independent of the primary voltage applied to the transmitter, the receiver can also perform a step-down operation. For example, the non-resonant inductive charging device having the transmitter and the receiver is suitable for charging a battery built in a portable electronic device. One advantage of this non-resonant inductive charging device is that a transformer composed of a secondary coil and a primary coil allows a large change in electromagnetic coupling coefficient. This means that the adjustment of the primary resonance frequency for canceling the leakage inductance of the primary coil and the adjustment of the secondary resonance frequency for canceling the leakage inductance of the secondary coil can be omitted. Furthermore, the primary resonant capacitor and the secondary resonant capacitor can be omitted. For example, a smartphone with a built-in receiver can be charged by simply placing it on a plate-like transmitter.

FIG. 1 is a schematic vertical sectional view showing a transformer of the IPT system of the first embodiment. FIG. 2 is a schematic plan view showing the transformer shown in FIG. FIG. 3 is a vertical sectional view showing a central rod around which a ground coil is wound. FIG. 4 is a schematic view showing a front plate, a front arm, and a central rod of the vehicle core. FIG. 5 is a schematic view showing the front plate, the front arm, and the geared motor of the vehicle core. FIG. 6 is a horizontal sectional view showing the forearm. FIG. 7 is a vertical sectional view showing the front plate. FIG. 8 is an axial sectional view showing a central rod around which a vehicle coil is wound. FIG. 9 is a radial cross-sectional view showing a central rod around which a vehicle coil is wound. FIG. 10 is a wiring diagram showing a non-resonant inductive charging (NR-IPT) circuit. FIG. 11 is an equivalent circuit diagram showing an accumulation period of NR-IPT. FIG. 12 is an equivalent circuit diagram showing an output period of NR-IPT. FIG. 13 is a schematic plan view illustrating the IPT system according to the second embodiment. FIG. 14 is a vertical sectional view showing the above-ground part of the IPT system shown in FIG. FIG. 15 is a block circuit diagram of a third embodiment showing a communication circuit for performing communication between the ground controller and the vehicle controller. FIG. 16 is a circuit diagram of Example 4 showing a receiver including a traction inverter as a switching circuit.

Preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the letter H indicates the height direction, the letter L indicates the longitudinal direction, and the letter W indicates the width direction.

Charging of the electric vehicle in the parking space will be described with reference to FIGS. FIG. 1 is a schematic vertical sectional view showing a transformer 100 of an inductive power supply (IPT) system installed in a parking space. FIG. 2 is a schematic plan view of the transformer 100. The transformer 100 includes a ground part 1 and a vehicle part 2. The ground part 1 is installed on the ground surface of the parking space, and the vehicle part 2 is installed on the bottom of the electric vehicle. The ground portion 1 has a ground coil 12 wound around a ground core 11. The vehicle unit 2 has a vehicle coil 22 wound around a vehicle core 21. The ground core 11 and the vehicle core 21 are made of soft ferrite called power ferrite.

The ground core 11 is disposed at the center in the longitudinal direction and the width direction of the parking space. The ground core 11 includes a front rod 111, a rear rod 112, a central rod 113, a front block 114, and a rear block 115. The ground coil 12 is wound around the central rod 113. As shown in FIG. 2, the front rod 111, the rear rod 112, the central rod 113, the front block 114, and the rear block 115 are arranged in a line in the longitudinal direction of the parking space.

The front block 114 magnetically couples the front end of the central rod 213 to the rear end of the front rod 111. The rear block 115 magnetically couples the rear end of the central rod 113 to the front end of the rear rod 112. Each of the front rod 111 and the rear rod 112 can be divided into a plurality of adjacent short rods in order.

The front rod 111, the rear rod 112, the front block 114, and the rear block 115 are fixed on the ground surface of the parking space. The central rod 113 is in contact with the upper portions of the front block 114 and the rear block 115. A bowl-shaped cover 116 made of an aluminum alloy covers the central rod 113, the front block 114, the rear block 115 and the ground coil 12. The front rod 111 protrudes forward from the bowl-shaped cover 116. The rear rod 112 protrudes rearward from the cover 116. The front rod 111 and the rear rod 112 are each made of a long plate. A protective bar 117 made of aluminum alloy extends along both sides of the front rod 111 and the rear rod 112. Each of the protection bars 117 has a square cross section. FIG. 3 shows a vertical section of the central rod 113 around which the ground coil 12 is wound. The cylindrical central rod 113 has an axis m3. If possible, the front block 114, center rod 113, rear block 115 and ground coil 12 are preferably embedded under the surface of the vehicle space or road.

The vehicle unit 2 has a vehicle coil 22 wound around a vehicle core 21. The vehicle core 21 includes a front plate 211, a rear plate 212, a central rod 213, a front block 214, a rear block 215, a front arm 216, and a rear arm 217. Each of the core members 211-217 made of power ferrite can be composed of a plurality of short core members. As a result, the core member 211-217 can be prevented from being damaged by a mechanical impact. The vehicle coil 22 is wound around the central rod 213. The central rod 213, the front block 214, and the rear block 215 are fixed to the bottom of the vehicle. The cylindrical central rod 213 has an axis m2.

The central rod 213 extends in the longitudinal direction of the vehicle between the left seat and the right seat of the electric vehicle. The central rod 213 and the vehicle coil 22 are covered with a nonmagnetic cover. The cubic front block 214 magnetically couples the front end of the central rod 213 and the rear end of the front rod 211. The cubic rear block 215 magnetically couples the rear end of the central rod 213 and the front end of the rear rod 212.

FIG. 4 schematically shows the front plate 211, the front arm 216, and the central rod 213. FIG. 5 schematically shows the front plate 211, the front arm 216, and the geared motor M1. FIG. 6 shows a horizontal cross section of the forearm 216. FIG. 7 shows a vertical cross section of the front plate 211. The front plate 211 extends in the width direction of the vehicle. The plate-like front plate 211 is in contact with the upper surface of the front rod 111. The front plate 211 has a protrusion 218 that protrudes upward.

Two lower end portions of the plate-like front arm 216 sandwich the protrusion 218 of the front plate 211 as shown in FIG. The side surface of the forearm 216 is in contact with the side surface of the protrusion 218. As shown in FIG. 7, a nonmagnetic metal pin 226 passes through the two forearms 216 and the protrusions 218. The pin 226 has an axis m4. Thereby, the front plate 211 can be rotated in a vertical plane.

Two upper ends of the front arm 216 sandwich the front block 214 of the vehicle core 21. The side surface of the front arm 216 is in contact with the side surface of the front block 214. As shown in FIG. 5, a shaft 227 having an axis m <b> 1 passes through the two front arms 216 and the front block 214. The shaft 227 fixed to the front arm 216 is connected to the shaft of the geared motor M1 fixed to the bottom plate of the vehicle. The geared motor M1 rotates the front arm 216 in the vertical plane. The front arm 216 extends in the horizontal direction when not charged, and extends obliquely when charged. As a result, the front plate 211 rises to the vicinity of the bottom plate of the electric vehicle when not charging, and contacts the front rod 111 of the ground core 11 during charging.

As shown in FIG. 6, the three flat surfaces of the forearm 216 are bonded to an aluminum reinforcing arm 221. Similarly, the rear arm 217 is also bonded to the reinforcing arm.

As shown in FIG. 7, the three flat surfaces except the lower surface of the front plate 211 are bonded to a reinforcing plate 221 made of aluminum alloy. Similarly, the three flat surfaces except the lower surface of the rear plate 212 are bonded to an aluminum alloy reinforcing plate. These reinforcing arms and reinforcing plates do not completely surround the power ferrite soft magnetic core member to prevent eddy currents.

The rear arm 217 has the same shape as the front arm 216, and the rear plate 212 has the same shape as the front plate 211. A rear plate 212 extending in the width direction of the vehicle is in contact with the upper surface of the rear rod 112 of the ground core 11. A protrusion 219 having the same shape as the protrusion 218 protrudes upward from the center of the rear plate 212.

The two lower ends of the rear arm 217 sandwich the protrusion 219 of the rear plate 212. The side surface of the rear arm 217 is in contact with the side surface of the protrusion 219. A nonmagnetic pin having an axis m4 passes through the two rear arms 217 and the protrusion 219. As a result, the rear plate 212 is rotatable in the vertical plane.

The two upper ends of the rear arm 217 sandwich the rear block 215. The side surface of the rear arm 217 is in contact with the side surface of the rear block 215. A shaft 228 having a shaft m1 passes through the two rear arms 217 and the rear block 215. The shaft 228 fixed to the rear arm 217 is connected to the shaft of the second geared motor fixed to the bottom plate of the vehicle. The second geared motor rotates the rear arm 217 in the vertical plane. As shown in FIG. 1, the rear arm 217 extends in the horizontal direction when not charged, and extends obliquely when charged. As a result, the rear plate 212 rises to the vicinity of the bottom plate of the electric vehicle during non-charging and contacts the rear rod 112 of the ground core 11 during charging.

8 and 9 show the central rod 213 around which the vehicle coil 22 is wound. The front end of the central rod 213 is in contact with the rear end surface of the front block 214. The rear end of the central rod 213 is in contact with the front end surface of the rear block 215. The front block 214, the central rod 213, the vehicle coil 22, and the rear block 215 are covered with a semicylindrical cover 231 made of an aluminum alloy. The bottom of the cover 231 is covered with a resin plate 230. The cover 231 serves as an air duct in which the cooling air flow AIR turns around the vehicle coil 22. A cooling air flow AIR formed by a cooling fan (not shown) is introduced into the cover 231 from the entrance of the cover 231 and discharged from the exit of the cover 231. The guide member 237 guides the cooling air flow AIR.

Four heat-dissipating copper plates 233 separated from each other are inserted between the central rod 213 and the vehicle coil 22 in the axial direction. The copper plate 233 has an outer plate portion 232 and an outer plate portion 234 that extend to the outside of the vehicle coil 22. The outer plate part 234 is in contact with the cover 231. Thereby, the center rod 213 and the vehicle coil 22 are cooled satisfactorily. A resin member 235 for electrical insulation is disposed between two copper plates 233 adjacent to each other.

The vehicle battery charging operation is described below. The ground unit 1 has a transmitter that supplies power to the ground coil 12 and a ground controller that controls the transmitter. The vehicle unit 2 includes a receiver that supplies electric power to the vehicle battery and a vehicle controller that controls the receiver.

The ground controller periodically supplies an alternating current to the ground coil 12 in order to detect the inductance value of the ground coil 12. When the electric vehicle exists on the ground portion 1, the inductance value of the ground coil 12 increases. When the inductance of the ground coil 12 exceeds a predetermined value, the transmitter supplies an alternating current for battery charging to the ground coil 12.

The vehicle controller detects an AC voltage induced in the vehicle coil 22. When the detected AC voltage exceeds a predetermined value, the vehicle controller determines that the front plate 211 and the rear plate 212 are located above the front rod 111 and the rear rod 112, and stops the electric vehicle. After the electric vehicle stops, the vehicle controller rotates the front arm 216 and the rear arm 217. Thereby, the front plate 211 contacts the upper surface of the front rod 111, and the rear plate 212 contacts the upper surface of the rear rod 112.

Thereby, the magnetic coupling coefficient between the vehicle coil 22 and the ground coil 12 is improved, and the secondary voltage induced in the vehicle coil 22 is increased. A receiver connected to the vehicle coil 22 rectifies the induced voltage of the vehicle coil 22. The rectified voltage is applied to the vehicle battery. The vehicle controller controls the receiver based on the state of charge of the vehicle battery in order to control the charging current of the battery.

When the state of charge of the vehicle battery exceeds a predetermined level, the vehicle controller rotates the front arm 216 and the rear arm 217 in opposite directions. Thereby, the front plate 211 and the rear plate 212 rise to the vicinity of the bottom plate of the electric vehicle. The ground controller stops power transmission when the inductance value of the ground coil 12 decreases.

The advantages of this embodiment are described. First, since the closed magnetic circuit is completed by the soft ferrite core, the excitation power is reduced. Next, since the coils 11 and 22 are wound around the cylindrical rods 113 and 213, the copper loss is greatly reduced. Next, since only a part of the vehicle core 21 is swung, the swing motor becomes compact. Furthermore, even if the height of the center rod 213 changes due to a change in tire pressure, the air gap between the vehicle core 21 and the ground core 11 can be canceled. Next, the horizontal misalignment margin between the vehicle coil 22 and the ground coil 12 is improved.

The ground portion 1 is disposed at the center portion in the width direction and the center portion in the longitudinal direction of the parking space. As a result, the ground portion 1 can be electromagnetically coupled to the vehicle portion 2 in both the forward parking and the backward parking.

A preferred example of the transmitter and receiver described above will be described with reference to FIGS. This inductive power supply that does not use resonance is named non-resonant inductive power supply (NR-IPT). The NR-IPT circuit includes a transformer 100, a transmitter 200, a receiver 300, a ground controller 500, and a vehicle controller 600. The primary coil of the transformer 100 is composed of the ground coil 12, and the secondary coil of the transformer 100 is composed of the vehicle coil 22. In this embodiment, the electromagnetic coupling coefficient k between the ground coil 12 and the vehicle coil 22 is set to about 0.5.

The transmitter 200 includes a transistor 201, a freewheeling diode 202, an inductor 203, and a ground coil 12. According to this embodiment, the inductor 203 consists of the leakage inductance of the ground coil 12. The + terminal of the ground-side DC power supply (not shown) is connected to the − terminal of the ground-side DC power supply through the inductor 203, the ground coil 12, and the transistor 201. The anode electrode of the diode 202 is connected to the connection point between the ground coil 12 and the transistor 201. The cathode electrode of the diode 202 is connected to the + terminal of the ground side DC power supply. In other words, the diode 202 is connected in antiparallel with the ground coil 12 including the inductor 203. The transmitter 200 supplies a primary current composed of an alternating current component and a direct current component to the ground coil 12 through the inductor 203.

The receiver 300 includes a transistor 301, an output diode 302, an inductor 303, and a vehicle coil 22. According to this embodiment, the inductor 303 comprises the leakage inductance of the vehicle coil 22. One end of the vehicle coil 22 is connected to the drain electrode of the transistor 301 through the inductor 303. The other end of the vehicle coil 22 is connected to the source electrode of the transistor 301. An anode electrode of the output diode 302 is connected to a connection point between the inductor 303 and the transistor 301. The cathode electrode of the output diode 302 is connected to the positive electrode of the battery 400. The negative electrode of the battery 400 is connected to the other end of the vehicle coil 22. The receiver 300 operating as a boost chopper applies the sum of the induced voltage of the vehicle coil 22 and the voltage of the inductor 303 to the battery 400.

An example of the charging operation of the NR-IPTC will be described below. When the ground controller 500 turns on the transistor 201, the primary current I 1 flowing through the ground coil 12 increases and magnetic energy is stored in the inductor 203.

When the voltage Vb of the battery 400 is less than a predetermined value, the vehicle controller 600 operates the receiver 300 as a boost chopper. The vehicle controller 600 turns on the transistor 301 when the secondary voltage V2 induced in the vehicle coil 22 exceeds a predetermined value. As a result, the secondary current I2 increases and magnetic energy is stored in the inductor 303. As a result, the primary current I1 increases to compensate for the change in magnetic flux of the transformer 100 due to the secondary current I2. Thereby, the magnetic energy of the inductor 203 further increases. When the number of turns of ground coil 12 and vehicle coil 22 is equal, primary current I1 is substantially equal to secondary current I2.

When the primary current I1 exceeds the predetermined threshold value I1th, the ground controller 500 turns off the transistor 201. Thus, the primary current I1 circulates through the freewheeling diode 202. As a result, the secondary voltage V2 induced in the vehicle coil 22 is almost zero. The vehicle controller 600 turns off the transistor 301 when the secondary voltage V2 becomes less than a predetermined value. When the transistor 301 is turned off, the magnetic energy of the inductor 303 causes the secondary current I2 to flow to the battery 4 through the diode 302. As a result, the magnetic energy and secondary current I2 of the inductor 303 rapidly decrease. As a result, the primary current I1 decreases to compensate for the magnetic flux change of the transformer 100. This means that the magnetic energy of the inductor 203 is reduced.

This forced reduction of the primary current I 1 means that the magnetic energy of the inductor 203 stored by the freewheeling current flowing through the diode 202 is transmitted to the vehicle coil 22 through the transformer 100. In other words, when the transistor 301 is turned off, the magnetic energy of the inductor 203 suppresses the decrease in the secondary current I2.

When the primary current I1 becomes less than a predetermined value, the ground controller 500 turns on the transistor 201. Thereby, the next cycle is started. When the voltage Vb of the battery 400 reaches a predetermined value, the vehicle controller 600 prohibits the transistor 301 from being turned on. The induced voltage V2 of the vehicle coil 22 is always lower than the voltage of the fully charged battery 400. Therefore, the fully charged battery 400 is not charged by the receiver 300. As a result, the secondary current I2 becomes zero and the primary current I1 decreases. The ground controller 500 prohibits turning on the transistor 201 if the increase rate of the primary current I1 is less than a predetermined value.

According to the charge control example, when the transistor 201 is turned on, the transistor 301 is turned on. Further, when the transistor 201 is turned off, the transistor 301 is turned off. However, other charging operation examples can be employed. For example, the vehicle controller 600 can turn off the transistor 301 when the secondary current I2 exceeds a predetermined threshold value I2th. Furthermore, the vehicle controller 600 can adjust the charging current of the battery 400 by controlling the threshold current value I2th. For example, the switching frequency of the transistor 201 is 20 kHz, and its duty ratio is 50%. Transistors 201 and 301 are preferably switched simultaneously, but can also be driven independently of each other. The transistor 301 can be turned off while the transistor 201 is on. The transistor 301 can be turned on while the transistor 201 is off.

FIG. 11 shows an accumulation period in which the transistors 201 and 301 are on. A ground-side DC power supply (not shown) applies a DC voltage V <b> 1 to the ground coil 12 through the inductor 203. The primary current I1 flowing through the ground coil 12 increases, and the inductor 203 induces a back electromotive force V1L. Due to the secondary voltage V2 induced in the vehicle coil 22, the secondary current I2 flowing through the inductor 303 is increased, and the inductor 303 generates a counter electromotive force V2L. Eventually, the inductors 203 and 303 accumulate magnetic energy during this accumulation period.

FIG. 12 shows an output period in which the transistors 201 and 301 are off. The magnetic energy stored in the inductor 203 circulates the primary current I1 through the diode 202. The magnetic energy stored in the inductor 303 causes the secondary current I2 to flow to the battery 400 through the diode 302. Since the secondary current I2 decreases rapidly, the primary current I1 also decreases rapidly. In other words, the magnetic energy stored in the inductor 203 suppresses the decrease of the secondary current I2 through the transformer 100. Eventually, the magnetic energy stored in inductors 203 and 303 charges battery 400 during this output period.

According to this NR-IPT, the magnetic energy stored in the leakage inductance of the transformer 100 is used for charging the battery 400. Therefore, this NR-IPT reduces the cost and power loss of the switching element and the resonant capacitor as compared with the conventional resonant IPT. In particular, power loss due to the resonance current flowing between the resonance capacitor and the leakage inductance is reduced.

The charging of the electric vehicle on the road just before the intersection with traffic lights will be described with reference to FIGS. FIG. 13 is a schematic plan view showing a part of the roadway in the vicinity of the intersection, and FIG. 14 schematically shows a vertical section of the roadway. The IPT system of this embodiment is essentially the same as the IPT system for the parking space.

The plurality of ground portions 1 are arranged at a predetermined interval in the longitudinal direction of the roadway 800 along the central portion in the width direction of the roadway 800. Each upper part 1 is composed of a ground core 11 and a ground coil 12. The ground core 11 includes a front rod 111, a rear rod 112, a central rod 113, a front block 114, and a rear block 115. The ground coil 12 is wound around the central rod 113. The ground core 11 is equal to the ground core 11 shown in FIG. However, the central rod 113, the front block 114, the rear block 115, and the ground coil 12 are embedded in the roadway 800. The embedded type ground portion 1 shown in FIGS. 13 and 14 can be arranged in a parking space.

Details of the ground core 11 will be described with reference to FIG. The front rod 111 includes a plate-like ferrite rod 111A and a soft magnetic asphalt layer 111B. The rear rod 112 includes a plate-like ferrite rod 112A and a soft magnetic asphalt layer 112B. The ferrite rods 111A and 112A are essentially the same as the front rod 111 and the rear rod 112 shown in FIG. The asphalt layer 111B is coated on the ferrite rod 111A. The asphalt layer 112B is coated on the ferrite rod 112A. The asphalt layers 111B and 112B are soft magnetic asphalt layers containing ferrite sand and ferrite gravel. It is also possible to employ a soft magnetic concrete layer containing ferrite sand and ferrite gravel instead of the soft magnetic asphalt layer. Ferrite sand and ferrite gravel have the same size as conventional asphalt or concrete sand and gravel. The front rod 111 and the rear rod 112 are laid on a conventional nonmagnetic asphalt layer 662 or a nonmagnetic concrete layer.

The central rod 113, the front block 114, the rear block 115, and the ground coil 12 formed by soft ferrite are accommodated in a concrete box 665. The upper end opening of the concrete box 665 is closed by a concrete plate 680. The rear end of the front rod 111 is in close contact with the upper end of the front block 114, and the front end of the rear rod 112 is in close contact with the upper end of the rear block 115. Each of the front block 114 and the rear block 115 extends downward along the inner wall surface of the concrete box 665. The central rod 113 is in contact with the front block 114 and the rear block 115. The transistor 201, the diode 202, and the controller 500 are housed in a concrete box 665.

Communication between the ground controller 500 and the vehicle controller 600 will be described with reference to FIG. Charging charges for electric vehicles that use the ground portion 1 installed at various parking spaces and intersections need to be accumulated monthly. For this reason, communication between the ground controller 500 and the vehicle controller 600 is required.

The communication circuit shown in FIG. 15 includes a ground side circuit 10A and a vehicle side circuit 10B. The ground side circuit 10A is included in the ground controller 500, and the vehicle side circuit 10B is included in the vehicle controller 600. The ground side circuit 10A includes an oscillation circuit 5A, a coil 3, a high frequency filter 6A, a rectifier circuit 7A, a low pass filter 8A, and a capacitor 9A. The vehicle side circuit 10B includes an oscillation circuit 5B, a coil 4, a high frequency filter 6B, a rectifier circuit 7B, a low pass filter 8B, and a capacitor 9B.

Coil 3 is wound around central rod 113 adjacent to ground coil 12. Coil 4 is wound around central rod 213 adjacent to vehicle coil 22. Coils 3 and 4 have fewer turns than coils 12 and 22, respectively. The oscillation circuit 5A supplies an oscillation current of 100 kHz to the parallel resonance circuit composed of the coil 3 and the capacitor 9A based on the ground command S3. The oscillation circuit 5B supplies an oscillation current of 100 kHz to the parallel resonance circuit composed of the coil 4 and the capacitor 9B based on the command S4.

The high frequency filter 6A sends the oscillation voltage component to the rectifier circuit 7A. The high frequency filter 6B sends the oscillation voltage component to the rectifier circuit 7B. The rectifier circuit 7A sends the rectified oscillation voltage component to the low-pass filter 8A. The rectifier circuit 7B sends the rectified oscillation voltage component to the low-pass filter 8B. The low pass filter 8A sends the low frequency component S1 of the rectified voltage to the ground controller 500, and the low pass filter 8B sends the low frequency component S2 of the rectified voltage to the vehicle controller 600. Further, the vehicle controller 600 sends its own ID information to the ground controller 500, and the ground controller 500 sends predetermined information to the center computer.

A fourth embodiment will be described with reference to FIG. According to this embodiment, the transistor 301 and the output diode 302 shown in the non-resonant inductive power supply (NR-IPT) circuit shown in the second embodiment are composed of the traction inverter 80. The traction inverter 80 fed from the vehicle battery 400 drives the traction motor 900. The traction motor 900 has a U-phase coil 91, a V-phase coil 92, and a W-phase coil 93 that are connected in a star shape. The traction motor 900 can employ various known types.

The traction inverter 80 has a U-phase leg, a V-phase leg, and a W-phase leg. The output terminal of the U-phase leg composed of the upper arm transistor 81 and the lower arm transistor 84 connected in series is connected to the U-phase coil 91. The output terminal of the V-phase leg composed of the upper arm transistor 82 and the lower arm transistor 85 connected in series is connected to the V-phase coil 92. The output terminal of the W-phase leg composed of the upper arm transistor 83 and the lower arm transistor 86 connected in series is connected to the W-phase coil 93. Transistors 81-86 consist of IGBTs with antiparallel diodes.

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The transmitter 200 is the same as the transmitter 200 shown in FIGS. The receiver 300 includes a traction inverter 80, diodes 71-73, an inductor 303, and a vehicle coil 22. One end of the vehicle coil 22 is connected to the anode electrode of the diodes 71 to 73 through the inductor 303. The cathode electrodes of the diodes 71 to 73 are separately connected to the three output terminals of the traction inverter 80. The other end of the vehicle coil 22 is connected to the negative electrode of the battery 400.

The operation of the traction inverter 80 will be described. The ground controller 500 controls the switching of the transistor 201 shown in FIGS. When the primary current I1 becomes lower than a predetermined low value, the transistor 201 is turned on. When the primary current I1 reaches a predetermined high value, the transistor 201 is turned off. The vehicle controller 600 detects the state of the transistor 201 based on the voltage change of the vehicle coil 22, and switches the lower arm transistors 84-86 of the traction inverter 80 in synchronization with the transistor 201. In other words, the lower arm transistors 84-86 perform the same switching operation as the transistor 301.

When the transistor 201 is turned on, the primary current I1 increases and the secondary voltage of the vehicle coil 22 increases. As a result, the lower arm transistors 84-86 are turned on. As a result, the secondary current I2 flowing through the inductor 303 increases, and magnetic energy is stored in the inductor 303. As a result, the primary current I1 flowing through the inductor 203 increases, and magnetic energy is stored in the inductor 203.

When the transistor 201 is turned off, the secondary voltage of the vehicle coil 22 changes rapidly. As a result, the lower arm transistors 84-86 are turned off. As a result, the magnetic energy stored in the inductor 303 supplies the secondary current I2 to the battery 400 through the antiparallel diode of the upper arm transistors 81-83 of the traction inverter 80. It is also possible to execute so-called synchronous rectification that synchronously turns on the upper arm transistors 81-83. In other words, the output diode 302 shown in FIGS. 10 to 12 includes an upper arm transistor 81-83 and an antiparallel diode.

Vehicle controller 600 prohibits lower arm transistors 84-86 from turning on when battery voltage Vb reaches a predetermined value. As a result, the secondary current I2 flowing through the vehicle coil 22 decreases. When the ground controller 500 detects this turn-off of the lower arm transistors 84-86 based on the decrease of the primary current I1, the ground controller 500 stops the switching of the transistor 201. According to this embodiment, the NR-IPT circuit is simplified. Furthermore, resistance loss is reduced.

The inductive power supply apparatus having a transmitter having a step-down chopper and a receiver having a step-up chopper operates in a non-resonant manner. This non-resonant type inductive power supply apparatus can be employed in applications other than electric vehicles. Since the receiver output voltage is essentially independent of the primary voltage applied to the transmitter, the receiver can also perform a step-down operation. For example, the non-resonant inductive charging device having the transmitter and the receiver is suitable for charging a battery built in a portable electronic device. One advantage of this non-resonant inductive charging device is that a transformer composed of a secondary coil and a primary coil allows a large change in electromagnetic coupling coefficient. This means that the adjustment of the primary resonance frequency for canceling the leakage inductance of the primary coil and the adjustment of the secondary resonance frequency for canceling the leakage inductance of the secondary coil can be omitted. Furthermore, the primary resonant capacitor and the secondary resonant capacitor can be omitted. For example, a smartphone with a built-in receiver can be charged by simply placing it on a plate-like transmitter.

Eventually, it is understood that this non-resonant type inductive power supply device is an isolated DCDC converter. The diode 202 can be changed to a transistor with an antiparallel diode. This transistor is equivalent to the secondary transistor 301. The diode 302 can be changed to a transistor with an anti-parallel diode. This transistor is equivalent to the primary transistor 201. Thereby, the transmitter 200 can operate as a receiver, and the receiver 300 can operate as a transmitter. In other words, this inductive power supply device having four transistors can constitute a bidirectional insulated DCDC converter.

Claims (25)

A soft magnetic ground core and ground coil installed near the surface of the parking space or road, a soft magnetic vehicle core and vehicle coil installed at the bottom of the vehicle, and a transmitter for supplying power to the ground coil In an induction power feeding apparatus including a receiver that supplies power of a vehicle coil to a vehicle battery, a ground controller that controls the transmitter, and a vehicle controller that controls the receiver,
The vehicle core has a fixed core fixed to the vehicle and a pair of movable cores magnetically coupled to the fixed core, and the distance between the tip of each movable core and the ground core can be changed. An inductive power supply device for an electric vehicle that is characterized.   2. The induction power feeding device for an electric vehicle according to claim 1, wherein each movable core is swung by a swing motor to change a mutual inductance value between the vehicle coil and the ground coil.   The pair of movable cores can be turned to the front arm having one end rotatably contacting the front end of the fixed core, the front plate supported by the other end of the front arm, and the rear end of the fixed core. The inductive power feeding device for an electric vehicle according to claim 2, further comprising: a rear arm having one end contacting the rear arm, and a rear plate supported by the rear arm.   4. The induction power feeding device for an electric vehicle according to claim 3, wherein each of the front plate and the rear plate extends substantially in the width direction of the vehicle.   The induction feeding device for an electric vehicle according to claim 4, wherein the front plate is supported by the front arm so as to be relatively movable, and the rear plate is supported by the rear arm so as to be relatively movable.   The fixed core of the vehicle core includes a central rod wound with a vehicle coil, a front block disposed between a front end portion and a front arm of the central rod extending in the longitudinal direction of the vehicle, and a rear end portion of the central rod. The inductive electric power feeder for electric vehicles of Claim 3 which has a rear block arrange | positioned between a rear arm and a rear arm.   The inductive power feeding device for an electric vehicle according to claim 6, wherein the front arm is in contact with the front block so as to be swingable, and the rear arm is in contact with the rear block so as to be swingable.   The inductive power feeding device for an electric vehicle according to claim 3, wherein the front arm and the rear arm are partially surrounded by a reinforcing plate made of a nonmagnetic metal.   4. The induction power feeding device for an electric vehicle according to claim 3, wherein the front plate and the rear plate are partially surrounded by a reinforcing plate made of a nonmagnetic metal.   The ground core includes a central rod wound with a ground coil, a front rod extending forward from a front end portion of the central rod, and a rear rod extending rearward from a rear end portion of the central rod. Induction power feeder for electric vehicles.   The ground core has a front block disposed between the central rod and the front rod, and a rear block disposed between the central rod and the rear rod, and the central rod is an upper portion of the front block and the rear block. The inductive electric power feeder for electric vehicles of Claim 10 which touches.   The induction feeding device for an electric vehicle according to claim 10, wherein the front rod and the rear rod are partially surrounded by a reinforcing plate made of a nonmagnetic metal.   The ground core has a front block disposed between the central rod and the front rod, and a rear block disposed between the central rod and the rear rod. The central rod, the front block, and the rear block are arranged in front. The induction feeder for an electric vehicle according to claim 10, which is buried below the rod and the rear rod.   14. The induction power feeding device for an electric vehicle according to claim 13, wherein the front rod and the rear rod have a soft magnetic asphalt layer or a soft magnetic concrete layer containing ferrite sand and ferrite gravel. The transmitter has a primary transistor connected in series with a primary inductor and ground coil connected in series, and a freewheeling diode connected in reverse parallel with the primary inductor and ground coil connected in series,
2. The induction for an electric vehicle according to claim 1, wherein the receiver includes a secondary inductor connected in series and a secondary transistor connected in parallel with the vehicle coil, and an output diode connecting one end of the secondary transistor to the output terminal. Power supply device.   16. The induction power feeding device for an electric vehicle according to claim 15, wherein the primary inductor mainly includes a leakage inductance of a ground coil, and the secondary inductor mainly includes a leakage inductance of a vehicle coil. The ground controller has an accumulation period for turning on the primary transistor and an output period for turning off the primary transistor,
16. The induction power feeding device for an electric vehicle according to claim 15, wherein the vehicle controller has an accumulation period in which the secondary transistor is turned on and an output period in which the secondary transistor is turned off.   The inductive power feeding device for an electric vehicle according to claim 17, wherein the accumulation period of the vehicle controller essentially overlaps with the accumulation period of the ground controller.   The induction power feeding device for an electric vehicle according to claim 1, wherein the ground controller and the vehicle controller communicate with each other through a pair of communication coils separately wound around the ground core and the vehicle core. A soft magnetic ground core and ground coil installed near the surface of the parking space or road, a soft magnetic vehicle core and vehicle coil installed at the bottom of the vehicle, and a transmitter for supplying power to the ground coil In an induction power feeding apparatus including a receiver that supplies power of a vehicle coil to a vehicle battery, a ground controller that controls the transmitter, and a vehicle controller that controls the receiver,
The transmitter has a primary transistor connected in series with a primary inductor and ground coil connected in series, and a freewheeling diode connected in reverse parallel with the primary inductor and ground coil connected in series,
The receiver has a secondary inductor connected in series with a secondary inductor and a vehicle coil connected in series, and an output diode that connects one end of the secondary transistor to the output terminal of the receiver. Inductive power feeder.   21. The induction power feeding device for an electric vehicle according to claim 20, wherein the primary inductor mainly includes a leakage inductance of a ground coil, and the secondary inductor mainly includes a leakage inductance of a vehicle coil. The ground controller has an accumulation period for turning on the primary transistor and an output period for turning off the primary transistor,
21. The induction power feeding device for an electric vehicle according to claim 20, wherein the vehicle controller has an accumulation period in which the secondary transistor is turned on and an output period in which the secondary transistor is turned off.   23. The induction power feeding device for an electric vehicle according to claim 22, wherein the accumulation period of the vehicle controller substantially overlaps the accumulation period of the ground controller.   21. The induction power feeding device for an electric vehicle according to claim 20, wherein the secondary inductor and the vehicle coil connected in series are connected to an output terminal of the traction inverter through a diode. A primary coil (12); a movable secondary coil (22); a transmitter (200) for supplying power to the primary coil (12); and a receiver (300) connected to the secondary coil (22). In the induction power feeding device,
The transmitter (200) includes a primary transistor (201) that switches a primary current flowing through the primary coil (12), and a freewheeling diode (202) that circulates the primary current through the primary coil (12).
The receiver (300) includes a secondary transistor (301) that switches a secondary current that flows through the secondary coil (22), and an output diode that connects one end of the secondary transistor (301) to the output terminal of the receiver (300). 302).

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