JP2005094862A - Contactless power feeding method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contactless power feeding method and a contactless power feeding apparatus capable of appropriately charging/discharging a storage battery. <P>SOLUTION: In the contactless power feeding apparatus 1, a resonance circuit 2 receives a voltage induced at a pickup coil 21 by the magnetic flux of a feeder line 50 and outputs an AC constant current. The constant current is converted into an AC constant voltage by an impedance conversion part 31, and the current converted into a DC output through a rectifying part 32 and a smoothing part 33 is supplied to motors 9 through drivers 8. In a charging/discharging control circuit 72, a first detecting means detects an output terminal voltage V<SB>out</SB>of the contactless power feeding apparatus 1. If a first determination means determines that a detected V<SB>out</SB>is equal to V<SB>1</SB>or higher, a charging means charges the storage battery 73. A second detecting means detects a voltage V<SB>b</SB>of the storage battery 73. If a second determination means determines that a detected V<SB>b</SB>is equal to V<SB>3</SB>or higher, a charge stop means stops the charging of the storage battery 73. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-contact power supply method and a non-contact power supply apparatus that bring a pickup close to a power supply line through which a high-frequency current flows and supply induced electromotive force generated in the pickup to a load provided on a moving body such as a transport vehicle.

  Conventionally, various transport systems for efficiently transporting materials by a moving body such as a transport vehicle have been proposed. One of them is that a pickup provided on a moving body is brought close to a power supply line, and an induced electromotive force generated by an alternating current flowing through the power supply line is supplied to the load in a physically non-contact state from the power supply line. There is a non-contact power feeding device (see, for example, Patent Document 1 and Patent Document 2).

  FIG. 10 is a circuit diagram showing a configuration of a conventional non-contact power feeding apparatus. In the figure, reference numeral 20 denotes a high-frequency power source that outputs an alternating constant current, and the constant current is supplied to a power supply line 50 connected to the high-frequency power source 20. The non-contact power feeding device 1 is mounted on the moving body 10, receives power from the power feeding line 50, and supplies power to the motor 9 of the moving body 10 via the driver 8. Here, the motor 9 is a load for driving the moving body 10 or a load for driving, for example, a robot mounted on the moving body 10.

  The non-contact power feeding device 1 includes a pickup coil 21 wound around a pickup core (not shown) close to a power supply line 50 through which a high-frequency current flows, a resonant capacitor 22 connected in parallel to the pickup coil 21, A rectifier 32 using a diode bridge connected in parallel to the resonant capacitor 22, a constant voltage circuit 5 that controls the current output from the rectifier 32 to a predetermined voltage, and a storage battery 73 connected in parallel to the constant voltage circuit 5 Is provided.

  By using the non-contact power feeding device 1 configured as described above, an electromotive force is generated in the pickup coil 21 by the magnetic flux generated around the power supply line 50 when an AC constant current is applied to the power supply line 50. In response to the electromotive force, the pickup coil 21 and the resonant capacitor 22 output an alternating constant current, the rectifier 32 rectifies the constant current, and the constant voltage circuit 5 regulates the rectified constant current to a predetermined voltage. In addition, power can be supplied to the motor 9 via the driver 8 and the storage battery 73 can be charged.

The storage battery 73 is provided to discharge the charged power and drive the motor 9 optimally when the load increases or when the current or voltage of the power supply line 50 decreases.
JP-A-5-328508 (page 3, FIG. 5) Japanese Patent Laid-Open No. 2001-116035 (page 2-3, FIG. 1)

  However, since the conventional contactless power supply device 1 is not provided with means for controlling charging / discharging of the storage battery 73, for example, the storage battery 73 is insufficiently charged as long as the contactless power supply device 1 continues to supply power to the motor 9. Even when the load increases, the storage battery 73 is always charged. That is, depending on the case, there is a possibility that power supply to the motor 9 cannot be sufficiently performed. In addition, the storage battery 73 may be discharged even when the power supply to the motor 9 is sufficient, and the power supply to the motor 9 cannot be sufficiently performed due to insufficient charging when the power supply by the discharge becomes necessary. There is also a fear.

  The present invention has been made in view of such circumstances, and an object of the present invention is to immediately charge the battery when the voltage of the storage battery becomes a predetermined value or less by providing a charge / discharge control circuit. It is possible to provide a non-contact power supply method and a non-contact power supply device that can supply appropriate power to the load by discharging the storage battery when the load is large.

  Another object of the present invention is to provide a booster circuit so that even when the discharge voltage of the storage battery is small, it is possible to supply appropriate power to the load, and to effectively use the power stored in the storage battery. Is to provide.

  The non-contact power supply method according to the first aspect of the present invention is a non-contact power supply method in which a coil is brought close to a power supply line through which a high-frequency current flows, and an induced electromotive force generated in the coil is supplied from a power receiving unit to a load of a moving body. In the power feeding method, the terminal voltage of the power receiving unit is detected, and whether or not the detected terminal voltage is equal to or higher than the first reference voltage value, or lower than the second reference voltage value lower than the first reference voltage value. When the determined terminal voltage is equal to or higher than the first reference voltage value, the storage battery is charged and the induced electromotive force is directly loaded from the power receiving unit to the load of the mobile body. When the determined terminal voltage is less than or equal to the second reference voltage value, the electric power charged in the storage battery is discharged to supply the electric power generated by the discharge of the storage battery to the load of the mobile body. It is characterized by doing.

  A non-contact power feeding device according to a second aspect of the present invention is a non-contact power supply device in which a coil is brought close to a power feeding line through which a high-frequency current flows, and an induced electromotive force generated in the coil is supplied from a power receiving unit to a load of a moving body and charges a storage battery. The power supply apparatus includes a charge / discharge control circuit that controls charging / discharging of the storage battery, and the charge / discharge control circuit includes a first detection unit that detects a terminal voltage of the power receiving unit, and a first detection unit. First determination means for determining whether the detected terminal voltage is equal to or higher than a first reference voltage value, or whether it is equal to or lower than a second reference voltage value lower than the first reference voltage value; When the terminal voltage determined by the first determination means is greater than or equal to the first reference voltage value, the charging means for charging the storage battery and the terminal voltage determined by the first determination means are the second reference voltage. If it is below the voltage value, And having a discharge means for discharging power charged in the serial accumulator.

  A contactless power supply device according to a third aspect of the present invention is the contactless power supply device according to the second aspect of the present invention, further comprising a booster circuit that boosts the discharge voltage of the storage battery.

  According to the first and second inventions, the first detection means detects the terminal voltage of the power receiving unit, and the first determination means determines whether the detected terminal voltage is equal to or higher than the first reference voltage value, or It is determined whether or not it is equal to or lower than a second reference voltage value that is lower than one reference voltage value.

  When the terminal voltage determined by the first determination unit is equal to or higher than the first reference voltage value, the charging unit charges the storage battery and supplies the induced electromotive force directly from the power receiving unit to the load of the moving body. In addition, when the terminal voltage determined by the first determination unit is equal to or lower than the second reference voltage value, the discharging unit discharges the electric power charged in the storage battery, so that the electric power generated by the storage battery is discharged. Supply power to

  Thereby, when the electric power supplied to the load of the mobile body is small, the battery can be charged without affecting the driving of the load. In addition, when the load is large, appropriate power can be supplied to the load by discharging the storage battery. In addition, since it is not necessary to cover the maximum power with the non-contact power feeding device alone, the capacity of the non-contact power feeding device can be reduced, and the size and cost can be reduced.

  According to the third invention, the booster circuit boosts the discharge voltage of the storage battery. As a result, even when the discharge voltage of the storage battery is small, it is possible to supply appropriate power to the load and to effectively use the power stored in the storage battery.

  According to the present invention, since the charging / discharging control circuit is provided, charging is performed without affecting the driving of the load by charging the storage battery when the power supplied to the load of the moving body is small. be able to. In addition, when the load is large, appropriate power can be supplied to the load by discharging the storage battery. In addition, since it is not necessary to cover the maximum power with the non-contact power feeding device alone, the capacity of the non-contact power feeding device can be reduced, and the size and cost can be reduced.

  Furthermore, according to the present invention, by providing the booster circuit, even when the discharge voltage of the storage battery is small, it is possible to supply appropriate power to the load and to effectively use the power stored in the storage battery.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

(Embodiment 1)
FIG. 1 is a circuit diagram showing a configuration of a non-contact power feeding apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 50 denotes a power supply line connected to a high-frequency power source 20 that outputs an alternating constant current. The pickup coil 21 of the non-contact power supply device 1 mounted on the moving body 10 is close to the power supply line 50. Are arranged. The non-contact power feeding device 1 includes a resonance circuit 2, a power reception unit 3, and a charge / discharge control unit 7.

  The resonance circuit 2 includes a pickup coil 21 and a resonance capacitor 22 connected in parallel with the pickup coil 21, and the inductance of the pickup coil 21 and the capacitance of the resonance capacitor 22 are in resonance with the frequency of the current flowing through the feeder line 50. The power is induced in the pickup coil 21 and functions as an AC constant current source.

  The power reception unit 3 uses an impedance conversion unit 31 that converts an alternating constant current output from the resonance circuit 2 into a constant voltage, and a diode bridge that performs full-wave rectification on the constant voltage alternating current output from the impedance conversion unit 31. And a smoothing unit 33 using a smoothing capacitor for smoothing the voltage output from the rectifying unit 32.

  The impedance converter 31 is configured such that the inductor 31a and the capacitors 31b and 31c are arranged in a π-type, and the inductance of the inductor 31a and the capacitance of the capacitors 31b and 31c are in resonance with the current flowing through the feeder line 50. .

  The charge / discharge control unit 7 includes a diode 71, a charge / discharge control circuit 72, a storage battery 73, a booster circuit 74, and a diode 75, and in parallel with the smoothing unit 33 on the output side of the non-contact power feeding device 1. Is provided.

Charge / discharge control circuit 72, as shown in FIG. 2, non-contact with the first detecting means 72a for detecting an output terminal voltage V _out of the power supply device 1, the output terminal voltage V _out which is detected by the first detecting means 72a First determination means 72b for determining whether or not is equal to or higher than V ₁ that is the first reference voltage value or lower than V ₂ (<V ₁ ) that is the second reference voltage value; a charging unit 72c for charging the battery 73 when the output terminal voltage V _out by determination unit 72b is determined to be V ₁ or more, when the output terminal voltage V _out by first determining unit 72b is a V ₂ below If it is determined, the discharge control means 72d for controlling the electric power charged in the storage battery 73 to be discharged, the second detection means 72e for detecting the voltage _{Vb of the} storage battery 73, and the second detection means 72e are detected. voltage V _b is the third reference voltage value der was Whether or not V ₃ or more, or a V ₄ second determining means for determining whether or not (<V ₃₎ is less 72f is a fourth reference voltage value, the voltage V _b by the second judging means 72f If it is determined that the voltage _Vb is equal to or higher than V ₃ , the charging stop unit 72g that stops charging the storage battery 73 and the second determination unit 72f determines that the voltage V _b is equal to or lower than V ₄ . Discharge stop means 72h for stopping discharge.

  The storage battery 73 is a lead storage battery having a rated voltage of DC voltage 48V. The diode 75 is provided to prevent the current output from the output terminal of the non-contact power feeding device 1 from directly flowing into the booster circuit 74.

  Further, motors 9, 9... Of the moving body 10 are connected to the output side of the non-contact power feeding device 1 via drivers 8, 8. Here, the motors 9, 9... Are loads for driving the moving body 10, or loads for driving a robot mounted on the moving body 10, for example. The drivers 8, 8... Are driven by motors 9, 9. Control the rotation speed or torque.

  When the impedance converter 31 is configured using the inductor 31a and the capacitors 31b and 31c, the inductance of the inductor 31a and the capacitance of the capacitors 31b and 31c are in resonance with the current flowing through the feeder line 50. The inductor 31a and the capacitors 31b and 31c may be arranged not only in the π type but also in the T type. Further, the impedance converter 31 may be configured by arranging two inductors and one capacitor in a π-type or a T-type so that the inductance and the capacitance are in resonance with the current flowing through the feeder line 50.

  When the rectifying unit 32 is configured, a diode that performs half-wave rectification may be used instead of a diode bridge that performs full-wave rectification.

Further, V ₁ (first reference voltage value) and V ₂ (second reference voltage value) of the output terminal voltage V _out in the first determination means 72b of the charge / discharge control circuit 72 are suitable for the non-contact power feeding system to be used. It may be set arbitrarily as described above. In particular, for the second reference voltage value V ₂ , the output voltage of the power receiving unit 3 (non-contact power supply device 1) is low when the load increases or when the current or voltage of the power supply line 50 decreases. Set assuming that

Similarly, V ₃ (third reference voltage value) and V ₄ (fourth reference voltage value) of the voltage V _b of the storage battery 73 in the second determination means 72f also conform to the limit of charging / discharging of the storage battery 73 to be used. In particular, for V ₄ that is the fourth reference voltage value, since the storage battery 73 is a lead storage battery, about 70 to 80% of the rated voltage of the lead storage battery in consideration of its discharge limit Set the range of as a guide.

  The storage battery 73 is not limited to a lead storage battery, and other secondary batteries, capacitors, or electric double layer capacitors may be used. If the rated capacity is small, a plurality of parallel batteries may be connected in parallel. When the rated voltage is small, a plurality of series connections may be used.

  A non-contact power feeding method of the non-contact power feeding apparatus having the above configuration will be described with reference to FIGS. When the AC constant current is supplied to the power supply line 50, the contactless power supply device 1 receives the voltage induced in the pickup coil 21 by the magnetic flux generated around the power supply line 50, and the resonance circuit 2 generates the AC constant current. The constant current is converted into an AC constant voltage by the impedance converter 31 and converted into a DC output (350 to 250 V: drooping characteristics shown in FIG. 5 corresponding to the load) through the rectifier 32 and the smoothing unit 33. The supplied current is fed to the motors 9, 9... Via the drivers 8, 8.

During this power supply, the charge / discharge control circuit 72 further receives the current whose voltage is smoothed by the smoothing unit 33 via the diode 71, and the first detection means 72 a outputs the output terminal voltage V _out of the non-contact power supply device 1. Is detected (S1). When the first determination unit 72b determines that the detected output terminal voltage V _out is equal to or higher than V ₁ (= 300V) (S2: YES), the charging unit 72c is connected to the power receiving unit 3 via the drivers 8, 8,. A part of the electric power supplied to the motors 9, 9... Is charged into the storage battery 73 by controlling the charging voltage and current (S3). And the 2nd detection means 72e detects the voltage _{Vb of the} storage battery 73 (S4). When the second determination unit 72f determines that the detected voltage V _b is less than V ₃ (= 48V) (S5: NO), the process returns to step S3 and the charging unit 72c charges the storage battery 73. On the other hand, when the detected voltage V _b was determined If it is V ₃ or the second judgment means 72f (S5: YES), the charging stopping unit 72g stops the charging of the battery 73 (S6).

The detected output voltage V _out is V less than ₁ in step S1 (S2: NO), and is V ₂ less (S7: YES) and when the first judging unit 72b determines, discharge control means 72d, for example By sending a discharge command signal to the booster circuit 74, the discharge of the electric power charged in the storage battery 73 is controlled (S8), and the booster circuit 74 boosts the discharge voltage of the storage battery 73 to an appropriate voltage (250 to 300V). , Power is supplied to the motors 9, 9. At this time, since the output of the power receiving unit 3 has a drooping characteristic, the discharge of the storage battery 73 and the power feeding by the power receiving unit 3 are balanced, and the power feeding to the motors 9, 9. ing. And the 2nd detection means 72e detects the voltage _{Vb of the} storage battery 73 (S9). When the second determination means 72f determines that the detected voltage V _b is higher than V ₄ (= 35V) (S10: NO), the process returns to step S8 and the discharge control means 72d controls the storage battery 73 to discharge. . On the other hand, if the detected voltage V _b is V ₄ less than the second determination unit 72f determines (S10: YES), discharge stop means 72h to stop the discharge of the battery 73 (S11).

Furthermore, the detected output voltage V _out is V less than ₁ in step S1 (S2: NO), and higher than V ₂ (S7: NO) and if the second judging unit 72b determines, charge / discharge control circuit 72 does not perform the charging / discharging operation of the storage battery 73, and returns to step S1 again. In this case, power is supplied to the motors 9, 9... Directly by the output from the power receiving unit 3 of the non-contact power supply device 1.

In charge / discharge control circuit 72 as described above, the second detecting means 72e detects the voltage V _b of battery 73, the second determination unit 72f voltage V _b is V detected by the second detection means 72e It is determined whether or not ₃ (third reference voltage value) or more, or V ₄ (fourth reference voltage value, V ₄ <V ₃ ) or less. When the voltage V _b by the second judging means 72f is determined to be V ₃ or more stops charging the charging stop means 72g storage battery 73, whereas the voltage V _b by the second judging means 72f If it is determined that it is V ₄ or less, the discharge stopping means 72 h stops discharging the storage battery 73. Thereby, since the overcharge and overdischarge of the storage battery 73 can be prevented, it is possible to extend the life of the storage battery 73.

Further, since the output of the power receiving unit 3 has a drooping characteristic, when the output voltage of the booster circuit 74 is set to a value slightly lower than V ₂ (second reference voltage value), the discharge of the storage battery 73 and the power receiving unit 3 The power supply can be balanced and appropriate power can be supplied to the load, and is maintained at approximately V ₂ (near the output voltage of the booster circuit 74).

  In addition, when the load decreases at this time, the power supply voltage by the power reception unit 3 increases and exceeds the voltage of the booster circuit 74, so that only the power supply from the power reception unit 3 is switched without control.

(Embodiment 2)
FIG. 6 is a circuit diagram showing a configuration of a non-contact power feeding apparatus according to Embodiment 2 of the present invention. In the figure, the same components as those in FIG. In the figure, the charge / discharge control unit 7 includes transistors 76 and 77, diodes 78 and 79, an inductor 80, an electric double layer capacitor (hereinafter referred to as a super capacitor) 81, in addition to the charge / discharge control circuit 72. And a current transformer (hereinafter referred to as “Current Transformer: CT”) 82.

  The collector of the transistor 76 is connected to the positive output terminal of the non-contact power feeding device 1, and the emitter of the transistor 76 and the collector of the transistor 77 are connected in common. The emitter of the transistor 77 is connected to the negative output terminal of the non-contact power feeding device 1, and the bases of the transistors 76 and 77 are connected to the charge / discharge control circuit 72, respectively. The cathode and anode sides of the diode 78 are connected to the collector and emitter of the transistor 76, respectively, and the cathode and anode sides of the diode 79 are connected to the collector and emitter of the transistor 77, respectively.

  An inductor 80, a super capacitor 81, and a CT 82 are connected in series between the common connection point of the transistors 76 and 77 and the emitter of the transistor 77. The supercapacitor 81 has intermediate characteristics between the battery and the electrolytic capacitor, and has an extremely high capacitance compared to the smoothing capacitor. Therefore, the supercapacitor 81 can be used as a substitute for a storage battery. The CT 82 detects the current I flowing into or out of the motors 9, 9... When the super capacitor 81 is charged or discharged.

Charge / discharge control circuit 72, as shown in FIG. 7, the non-contact with the first detecting means 72a for detecting an output terminal voltage V _out of the power supply device 1, the output terminal voltage V _out which is detected by the first detecting means 72a A first determination unit 72b for determining whether or not V ₁ (first reference voltage value) or more, or V ₂ (<V ₁ , second reference voltage value) or less, and a super capacitor 81 a second detecting means 72e for detecting a voltage V _b of, whether the voltage V _b detected by the second detection means 72e is V ₃ (third reference voltage value) or more, or V ₄ (<V ₃ , Fourth reference voltage value) or less, second determination means 72f for determining whether or not the current I is detected by the CT 82, acquisition means 72i for acquiring the current I detected by the CT 82, and the current I acquired by the acquisition means 72i is the reference current value third determination hand determines whether or is I ₁ or more and 72 j and the charge / discharge for controlling the charging / discharging of the supercapacitor 81 by turning on / off the transistors 76 and 77 based on the determination result of the first determination means 72b, the second determination means 72f, or the third determination means 72j. Control means 72k. The reference current value I ₁ is set according to the current that can be charged by the super capacitor 81.

  A non-contact power feeding method of the non-contact power feeding apparatus having the above configuration will be described with reference to FIGS. When the AC constant current is supplied to the power supply line 50, the contactless power supply device 1 receives the voltage induced in the pickup coil 21 by the magnetic flux generated around the power supply line 50, and the resonance circuit 2 generates the AC constant current. The constant current is supplied to the motors 9, 9... Via the impedance converter 31, the rectifier 32, the smoothing unit 33, and the drivers 8, 8,.

During this power supply, the first detection means 72a detects the output terminal voltage _Vout of the non-contact power supply device 1 in the charge / discharge control circuit 72 (S21). When the first determination means 72b determines that the detected output terminal voltage _Vout is equal to or higher than V ₁ (= 300V) (S22: YES), the charge / discharge control means 72k turns on the transistor 76 and turns on the transistor 77 Is turned off to charge part of the power supplied to the motors 9, 9... Via the drivers 8, 8,... To the supercapacitor 81 by controlling the charging voltage and current (S23).

Next, the second detection means 72e detects the voltage _Vb of the super capacitor 81 (S24). When the second determination unit 72f determines that the detected voltage V _b is less than V ₃ (= 48V) (S25: NO), the acquisition unit 72i acquires the detection current I from the CT 82 (S26). When the third determination unit 72j determines that the acquired current I is equal to or greater than I ₁ (S27: YES), the process returns to step S23 and the charge / discharge control unit 72k charges the supercapacitor 81. On the other hand, when the third determination unit 72j determines that the acquired current I is less than I ₁ (S27: NO), or in step S25, the second determination unit determines that the detected voltage V _b is V ₃ or more. When 72f determines (S25: YES), the charge / discharge control means 72k stops charging the supercapacitor 81 by turning off the transistor 76 (S28).

The detected output voltage V _out is lower than V ₁ at step S21 (S22: NO), and is V ₂ less (S29: YES) and when the first judging unit 72b determines, charge / discharge control unit 72k is The transistor 76 is turned off and the transistor 77 is turned on and then turned off to discharge the power charged in the supercapacitor 81 (S30).

Specifically, when transistor 77 is first turned on, the discharge current from supercapacitor 81 returns to supercapacitor 81 again via inductor 80, transistor 77, and CT82, and circulates in this loop. At this time, the inductor 80 functions as a kind of battery for accumulating magnetic energy, and boosts the discharge voltage of the super capacitor 81. Subsequently, when the transistor 77 is switched from on to off, the discharge voltage from the super capacitor 81 boosted by the inductor 80 is supplied to the motors 9, 9. Note that the discharge voltage of the supercapacitor 81 can be boosted from V _b (= 48 V) to about 250 to 300 V by appropriately controlling the on and off times of the transistor 77. At this time, since the output of the power reception unit 3 has a drooping characteristic, the discharge of the super capacitor 81 and the power supply by the power reception unit 3 are balanced, and the power supply to the motors 9, 9. It has been broken.

Subsequently, the second detection means 72e detects the voltage _Vb of the super capacitor 81 (S31). When the second determination unit 72f determines that the detected voltage V _b is higher than V ₄ (= 35V) (S32: NO), the acquisition unit 72i acquires the detection current I from the CT 82 (S33). When the third determination unit 72j determines that the acquired current I is less than I ₁ (S34: NO), the process returns to step S30, and the charge / discharge control unit 72k discharges the supercapacitor 81. On the other hand, when the third determination means 72j determines that the acquired current I is equal to or greater than I ₁ (S34: YES), or in step S32, the second determination means indicates that the detected voltage V _b is equal to or less than V _4. When 72f determines (S32: YES), the charge / discharge control means 72k stops the discharge of the super capacitor 81 by turning on the transistor 77 (S35).

Furthermore, the detected output voltage V _out is V less than ₁ in step S21 (S22: NO), and higher than V ₂ (S29: NO) and if the second judging unit 72b determines, charge / discharge control circuit 72 does not perform the charging / discharging operation of the super capacitor 81, and returns to step S21 again. In this case, power is supplied to the motors 9, 9... Directly by the output from the power receiving unit 3 of the non-contact power supply device 1.

In charge / discharge control circuit 72 as described above, the second detecting means 72e detects the voltage V _b of the super capacitor 81, a second determination unit 72f is the voltage V _b detected by the second detection means 72e is It is determined whether or not it is V ₃ (third reference voltage value) or more, or V ₄ (fourth reference voltage value, V ₄ <V ₃ ) or less, and the third determination means obtains it. It is determined whether or not the current I acquired by the means 72i is equal to or greater than I ₁ (reference current value). Then, the voltage V _b by the second judging means 72f is determined to be V ₃ or more, when the current I is determined to be less than I ₁ by the third determination unit 72j are charge / discharge control means 72k stops charging the supercapacitor 81, while the second determination means 72f determines that the voltage _Vb is V ₄ or less, and the third determination means 72j determines that the current I is I ₁ or more. If so, the charge / discharge control means 72k stops discharging the supercapacitor 81. Therefore, since the control based on the magnitude of the load is taken into consideration as compared with the case of the first embodiment, overcharge and overdischarge of the supercapacitor 81 can be more strictly prevented. It is possible to extend the service life.

  In the first embodiment described above, the non-contact power feeding device 1 includes the booster circuit 74. However, the present invention is not limited to this, and the case where the discharge voltage of the storage battery 73 is necessary and sufficient for power feeding to the motors 9, 9,. Instead of providing the booster circuit 74, for example, a switching circuit may be provided.

Furthermore, in the _first and second embodiments described above, V ₁ that is the first reference voltage value and V ₂ that is the second reference voltage value are set to different values. It may be set to a value.

It is a circuit diagram which shows the structure of the non-contact electric power feeder which concerns on Embodiment 1 of this invention. It is a block diagram of the charge / discharge control circuit which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the charge / discharge control part which concerns on Embodiment 1 of this invention. It is a figure explaining the state of the non-contact electric power feeding method and storage battery of the non-contact electric power feeder which concern on Embodiment 1 of this invention. It is a figure which shows the drooping characteristic of the DC output voltage of the power receiving part according to output electric power. It is a circuit diagram which shows the structure of the non-contact electric power feeder which concerns on Embodiment 2 of this invention. It is a block diagram of the charge / discharge control circuit which concerns on Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the charging / discharging control part which concerns on Embodiment 2 of this invention. It is a figure explaining the state of the non-contact electric power feeding method and super capacitor of the non-contact electric power feeder which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the structure of the conventional non-contact electric power feeder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Non-contact electric power feeder 2 Resonant circuit 10 Mobile body 21 Pickup coil 22 Resonant capacitor 3 Power receiving part 31 Impedance conversion part 32 Rectification part 33 Smoothing part 7 Charge / discharge control part 71,75,78,79 Diode 72 Charge / discharge control circuit 73 Storage Battery 74 Booster Circuit 76,77 Transistor 8 Driver 81 Super Capacitor (Electric Double Layer Capacitor)
9 Motor

Claims (3)

In a non-contact power feeding method of bringing a coil close to a power feeding line through which a high-frequency current flows, supplying an induced electromotive force generated in the coil from a power receiving unit to a load of a moving body, and charging a storage battery,
Detecting the terminal voltage of the power receiving unit,
Determining whether the detected terminal voltage is greater than or equal to the first reference voltage value, or less than or equal to the second reference voltage value lower than the first reference voltage value;
When the determined terminal voltage is equal to or higher than the first reference voltage value, the storage battery is charged, and the induced electromotive force is directly supplied from the power receiving unit to the load of the mobile body,
When the determined terminal voltage is less than or equal to the second reference voltage value, the electric power charged in the storage battery is discharged to supply the electric power generated by the discharge of the storage battery to the load of the mobile body. Non-contact power supply method. In a non-contact power feeding device that brings a coil close to a power feeding line through which a high-frequency current flows, supplies an induced electromotive force generated in the coil to a load of a moving body, and charges a storage battery.
A charge / discharge control circuit for controlling charge / discharge of the storage battery;
The charge / discharge control circuit includes:
First detecting means for detecting a terminal voltage of the power receiving unit;
It is determined whether or not the terminal voltage detected by the first detection means is greater than or equal to the first reference voltage value, or less than or equal to the second reference voltage value that is lower than the first reference voltage value. First determination means;
When the terminal voltage determined by the first determination means is equal to or higher than the first reference voltage value, the charging means for charging the storage battery;
A non-contact power feeding apparatus comprising: a discharging unit that discharges the electric power charged in the storage battery when the terminal voltage determined by the first determining unit is equal to or lower than the second reference voltage value.   The contactless power supply device according to claim 2, further comprising a booster circuit that boosts a discharge voltage of the storage battery.

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