JP2012044762A - Non-contact power feeder with overvoltage protection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power feeder with overvoltage protection, in which an overvoltage protection part detects an overvoltage by a smoothed voltage firstly, short circuit can be executed after the start of a secondary side circuit secondly, and power feeding is easily and surely stopped accompanying the execution of the short circuit thirdly.SOLUTION: A non-contact power feeder 10 includes an overvoltage protection part 21 which is provided between a rectification part 5 of a secondary side circuit 2 and a smoothing part, and short-circuits the secondary side circuit 2 and a secondary coil 4 when detecting that an overvoltage is generated. The overvoltage protection part 21 includes detection means, amplification means 23, short circuit means 24 and backflow prevention means 25, etc. Further, delay means 32 is provided to operate the overvoltage protection part 21 with a delay after the secondary side circuit 2 is started at the start of power feeding. Also, the non-contact power feeder 10 includes a detection part 38 for detecting a current change or voltage change of a primary side circuit 11 based on the short circuit, and a control part 39 for turning off a power source 13 of the primary side circuit 11 on the basis of the detection.

Description

  The present invention relates to a contactless power supply device with overvoltage protection. That is, the present invention relates to overvoltage protection of a non-contact power feeding device that supplies power in a non-contact manner with an air gap from the ground side and primary side to the vehicle side and secondary side.

《Technical background》
A non-contact power supply device that supplies electric power from the outside to a vehicle such as an electric vehicle without mechanical contact such as a cable has been developed and put into practical use based on demand.
In this non-contact power feeding device, based on the mutual induction action of electromagnetic induction, air of about several tens to several hundreds of millimeters is transferred from a primary coil placed on the ground side or the like to a secondary coil mounted on a vehicle or other moving body. Electric power is supplied while a gap is present and the contact position is not contacted (see also FIG. 4 and the like described later).

<Conventional technology>
The secondary side circuit of such a non-contact power feeding device is usually provided with a rectifying unit, a smoothing unit, a charging unit, a battery, etc., and the induced electromotive force from the secondary coil is converted into a direct current and smoothed. , Constant voltage, low voltage, etc., are supplied to the battery.
By the way, in such a non-contact power feeding device, for example, due to fluctuations in the air gap (increased coupling coefficient due to excessive approach), failure of the capacitor of the smoothing part, etc., the secondary coil and the secondary circuit Overvoltage may occur, and the secondary circuit may fail due to the overvoltage. The output voltage of the secondary coil rises abnormally, causing an overvoltage to flow in the secondary circuit, and the secondary coil, rectifier, smoothing unit, charging unit, load, etc., which are the components of the circuit, are damaged by the application of overvoltage. There is a risk of burning.

Therefore, as shown in FIG. 5, in the non-contact power feeding device 1, an overvoltage protection unit (short circuit) 3 is conventionally provided in the secondary circuit 2.
When the overvoltage protection unit 3 detects the occurrence of overvoltage with respect to the secondary coil 4, the secondary side circuit 2 and the secondary coil 4 are short-circuited to protect the secondary side circuit 2. In the figure, 5 is a rectifying unit, 6 is a smoothing unit, 7 is a charging unit, 8 is a battery, and 9 is a load.
The overvoltage protection unit 3 is conventionally provided between the secondary coil 4 and the rectification unit 5 of the secondary side circuit 2.
That is, if the overvoltage protection unit 3 is provided in a circuit including the smoothing unit 6 such as between the rectifying unit 5 and the smoothing unit 6 or after the smoothing unit 6, a reverse current and an inrush current from the smoothing unit 6 side at the time of a short circuit. The reason is that the inflow current becomes excessive and there is a risk that the short-circuit element such as the thyristor constituting the overvoltage protection unit 3 may be damaged or failed.
Of course, it is conceivable to adopt a thyristor or the like that can withstand this, but the cost burden becomes excessive. Therefore, in this conventional non-contact electric power feeder 1, the system which short-circuits before rectification was employ | adopted.
In addition, instead of providing the overvoltage protection unit 3 in this way, a fuse that interrupts the circuit due to overvoltage is partly connected to the secondary circuit 2 in some cases, but it takes time to replace the fuse. There was a big difficulty in man-hours, etc., and it did not reach full-scale adoption.

By the way, the following subject was pointed out about this kind of prior art non-contact electric power feeder 1 with an overvoltage protection.
<First problem>
First, in this type of conventional non-contact power feeding device 1, a problem has been pointed out that the driving voltage of the secondary circuit 2 and the driving voltage of the overvoltage protection unit 3 are not matched.
That is, as described above, the overvoltage protection unit 3 is provided between the secondary coil 4 and the rectification unit 5, and a system that detects and shorts overvoltage before rectification and smoothing is employed. Therefore, the voltage detected by the overvoltage protection unit 3 as an overvoltage, that is, the short-circuiting voltage before rectification and smoothing, and the input voltage after rectification and smoothing to the secondary side circuit 2 such as the charging unit 7 are slightly different. It was happening.
Therefore, for example, even when the voltage is not overvoltage for the secondary circuit 2, there is a case where the overvoltage protection unit 3 performs a short circuit as an overvoltage, which is wasteful. An unnecessary short circuit is likely to occur, and an improvement has been desired.

<< Second problem >>
Secondly, in the conventional contactless power supply device 1 of this type, when the secondary side circuit 2 rises slowly, a short circuit is performed in the overvoltage protection unit 3 before the secondary side circuit 2 is started. In many cases, it has been pointed out that the charging unit 7 of the secondary circuit 2 may not be activated.
That is, at the start of power supply, in the secondary side circuit 2, before the charging unit 7 and the like start up and start up (it often takes about 0.3 seconds for the start-up, for example), power is not consumed and voltage is inevitably generated. Will rise. In many cases, the overvoltage protection unit 3 detects this as an overvoltage and short-circuits the secondary circuit 2 and the secondary coil 4.
That is, there is a problem that the overvoltage protection unit 3 is activated before the charging unit 7 and the like are activated, and as a result, the secondary side circuit 2 may not be activated although the overvoltage that should be a problem is not generated. It was.

《Third problem》
Third, when the secondary side circuit 2 is short-circuited in the overvoltage protection unit 3, it is necessary to immediately stop the power supply in the primary side circuit. In the conventional non-contact power supply device 1 of this type, It has been pointed out that the detection means and the communication means are complicated and the power supply stoppage may be delayed.
That is, in this type of conventional non-contact power feeding device 1, the detection means detects that the overvoltage protection unit 3 has been activated in the secondary circuit 2 and the short circuit has been performed, and the detected short circuit execution information is the primary. Instead of using a wiring cable (the wiring cable cannot be used because it is non-contact), it is transmitted to the side circuit using some communication means.
However, the circuit configuration of such detection means and communication means is complicated, communication failures and malfunctions frequently occur, and the power-off operation of the primary side circuit is delayed, so that wasteful power supply from the primary side circuit is caused. There were problems such as being done.

<< About the present invention >>
The non-contact power feeding device with overvoltage protection according to the present invention has been made to solve the above-described problems of the prior art in view of such a situation.
In the present invention, firstly, the overvoltage protection unit detects an overvoltage with a smoothed voltage, and secondly, the overvoltage protection unit can perform a short circuit after the secondary side circuit rises, Furthermore, it is an object of the present invention to propose a non-contact power feeding device with overvoltage protection that can easily and reliably stop power feeding when a short circuit is performed.

<About each claim>
The technical means of the present invention for solving such a problem is as follows, as described in the claims.
About Claim 1, it is as follows.
The contactless power supply device with overvoltage protection according to claim 1 is based on the mutual induction action of electromagnetic induction, and the electric power is present while the air gap exists from the primary coil of the primary side circuit to the secondary coil of the secondary side circuit. Supply. An overvoltage protection unit is provided between the rectification unit and the smoothing unit for the secondary side circuit. When the overvoltage protection unit detects an overvoltage occurrence in the secondary side circuit, The secondary coil is short-circuited to protect the secondary side circuit. The claim 2 is as follows.
The contactless power supply device with overvoltage protection according to claim 2, wherein the overvoltage protection unit includes a detection unit that detects an overvoltage in the smoothing unit, and a short circuit unit that performs a short circuit based on the detection by the detection unit. And backflow prevention means for preventing current backflow from the smoothing section to the short-circuit means.

About Claim 3, it is as follows.
According to a third aspect of the present invention, there is provided the non-contact power supply apparatus with overvoltage protection according to the second aspect, wherein the overvoltage protection unit includes a zener diode as the detection means for detecting the overvoltage in the smoothing unit as a breakdown voltage, Amplifying means for amplifying current, a turn-on based on the gate current from the amplifying means, and a protective thyristor as the short-circuit means for short-circuiting immediately after the rectifier, and the smoothing to the protective thyristor at the time of short-circuit And a backflow preventing diode as backflow preventing means for preventing current backflow from the section side.
About Claim 4, it is as follows.
According to a fourth aspect of the present invention, there is provided a contactless power supply device with overvoltage protection, wherein the overvoltage protection unit further includes delay means. The delay means is characterized in that the overvoltage protection unit is operable after the secondary circuit is started up at the start of power supply.
About Claim 5, it is as follows.
The contactless power supply device with overvoltage protection according to claim 5, wherein, in claim 1, when the secondary circuit is short-circuited, a detection unit that detects a current change or a voltage change of the primary circuit based on the short circuit; And a control unit that turns off the power supply of the primary circuit based on the detection of the detection unit.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) In the non-contact power feeding device, the secondary coil is positioned corresponding to the primary coil, and power is supplied.
(2) That is, electric power is supplied from the primary side circuit to the secondary side circuit by the mutual induction action of electromagnetic induction.
(3) In the secondary side circuit, alternating current from the secondary coil is supplied to the battery via the rectifying unit, the overvoltage protection unit, the smoothing unit, the charging unit, and the like.
(4) In the present invention, an overvoltage protection unit is provided in the secondary circuit. The overvoltage protection unit includes an overvoltage detection unit, a current amplification unit, a short circuit unit, and the like. When an overvoltage occurrence is detected in the secondary coil and the secondary circuit, the overvoltage protection unit is short-circuited to protect it.
(5) The detecting means of the overvoltage protection unit, for example, a Zener diode is connected in parallel before the smoothing unit, and detects the occurrence of overvoltage with respect to the smoothed voltage. That is, overvoltage is detected for a voltage that matches the input voltage to the charging unit or the like.
(6) At the time of a short circuit, there is a possibility that a backflow current flows from the smoothing part side to a short circuit means of the overvoltage protection part, for example, a protection thyristor, but this is avoided by a backflow prevention means such as a backflow prevention diode.
(7) The overvoltage protection unit is provided with delay means. Therefore, when starting the power supply, the overvoltage protection unit can be operated after the secondary circuit such as the charging unit or the battery is started up. At the start of power supply, the overvoltage protection unit does not short-circuit before the charging unit or the like starts up.
(8) When a short circuit is implemented by the overvoltage protection unit, the detection unit detects changes in the voltage or current of the primary circuit based on the short circuit, and the control unit turns off the power supply. In this way, power supply is stopped reliably and immediately with a simple configuration.
(9) Now, the non-contact power feeding device with overvoltage protection of the present invention exhibits the following effects.

<< First effect >>
First, the overvoltage protection unit detects an overvoltage with the smoothed voltage. That is, in the non-contact power feeding device with overvoltage protection according to the present invention, the detection means of the overvoltage protection unit detects the overvoltage in the smoothing unit, and based on this, the short circuiting unit performs a short circuit to protect the secondary side circuit. .
There is no difference between the voltage detected by the overvoltage protection unit as an overvoltage, that is, the short-circuit execution voltage, and the input voltage to the secondary circuit such as the charging unit. Both are rectified and smoothed voltages.
Therefore, this kind of prior art, that is, the prior art that detects the overvoltage based on the voltage before rectification and smoothing, and detects the overvoltage protection unit, the drive voltage, the charging unit, etc. Occurrence of a slightly different situation from the driving voltage of the secondary circuit is avoided.
Therefore, for example, even when the voltage is not high enough for the secondary circuit such as the charging unit, a case of short-circuiting as an overvoltage does not occur, and the occurrence of useless short-circuiting is prevented. In addition, the backflow current from the smoothing part side to the short circuit means at the time of a short circuit is reliably avoided by providing the backflow prevention means.
Thus, overvoltage protection comes to work optimally for the non-contact power feeding device. It is possible to prevent the constituent parts of the secondary side circuit from being damaged or burned out by overvoltage, and to realize reliable protection thereof.

<< Second effect >>
Secondly, overvoltage protection can be implemented after the secondary side circuit such as a charging unit rises. That is, the non-contact power feeding device with overvoltage protection according to the present invention is provided with a delay means, and after the secondary side circuit such as the charging unit starts up and starts up at the start of power feeding, the overvoltage protection unit is delayed by delaying the timing. It is possible to operate.
Therefore, as in the above-described conventional technology, it is avoided that the overvoltage protection unit performs a short circuit before the secondary circuit such as the charging unit starts up and starts up when power supply is started. Although the overvoltage protection unit does not generate overvoltage due to the air gap fluctuation or failure that is originally intended, the overvoltage protection unit works, and as a result, it is possible to reliably prevent the occurrence of a situation where the secondary circuit cannot be started. Is done.
Therefore, also from this aspect, the overvoltage protection works optimally for the non-contact power feeding device.

《Third effect》
Thirdly, power supply is easily and reliably stopped as the short circuit is performed. That is, in the non-contact power feeding device with overvoltage protection according to the present invention, when the secondary side circuit is short-circuited by the overvoltage protection unit, the detection unit detects a current change or a voltage change of the primary side circuit based on the short-circuit. In the control unit, the power source of the primary circuit is turned off.
Compared with this kind of conventional technology, that is, a short circuit is detected by providing some detection means, and the short circuit is transmitted to the primary side circuit by using any communication means, a simple configuration. Thus, the power supply by the primary side circuit is stopped reliably and immediately without any risk of communication failure or malfunction. It is also reliably avoided that the power-off operation is delayed and unnecessary power supply is performed.
Therefore, also from this aspect, the overvoltage protection works optimally for the non-contact power feeding device.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

It is a circuit diagram of the principal part of a primary side circuit and a secondary side circuit for description of the form for inventing about the non-contact electric power feeder with an overvoltage protection which concerns on this invention. FIG. 5 is a circuit diagram of the remaining part of the secondary side circuit for explaining the embodiment for carrying out the invention. It is a circuit diagram for description of the non-contact power feeding device. For the description of the non-contact power feeding device, (1) is an overall explanatory diagram, and (2) is a block diagram of the configuration. It is a structure block diagram of the principal part for description of the non-contact electric power feeder of this kind prior art.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
<< About the non-contact electric power feeder 10 >>
First, the non-contact power feeding device 10 which is a premise of the present invention will be generally described with reference to FIG. 3 and FIG.
The non-contact power feeding device 10 is non-contact with an air gap G from the primary coil 12 of the primary side circuit 11 to the secondary coil 4 of the secondary side circuit 2 based on the mutual induction action of electromagnetic induction. Supply power at the corresponding position. The primary side circuit 11 is fixedly disposed on the ground A side, and the secondary side circuit 2 is mounted on a moving body such as the vehicle B side.

Such a non-contact power supply apparatus 10 will be described in further detail. First, the primary circuit 11 on the power supply side, the track side, and the primary side is stationaryly arranged on the ground, road surface, floor surface, and other ground A side in the power supply station C and other power supply areas.
On the other hand, the secondary circuit 2 on the power receiving side, the pickup side, and the secondary side is mounted on an electric vehicle (EV vehicle), a vehicle B such as a train, and other moving bodies. The secondary side circuit 2 can be used not only for driving but also for non-driving, and is typically connected to an in-vehicle battery 8 as shown in the figure, but directly connected to various loads 9. Sometimes connected.
The primary coil 12 of the primary side circuit 11 and the secondary coil 4 of the secondary side circuit 2 are air that is a slight gap space of several tens mm to several hundreds mm, for example, about 50 mm to 150 mm, during power feeding. While the gap G exists, the corresponding positions are close to each other without contact. In the illustrated example, the corresponding positions are vertically located.
Further, in the case of power feeding, a stop power feeding method in which the secondary coil 4 is stopped on the primary coil 12 or the like is representative. In the case of the stop power feeding method, the primary coil 12 and the secondary coil 4 are: It consists of a symmetrical structure that can be paired vertically. On the other hand, a mobile power feeding method in which the secondary coil 4 feeds power while traveling on the primary coil 12 at a low speed is also possible.

The primary coil 12 of the primary side circuit 11 is connected to a power source 13 in which an inverter is used. In the primary side circuit 11 of FIG. 3, 14 is a choke coil, 15 is a capacitor for series resonance, and 16 is a capacitor for parallel resonance.
The secondary coil 4 of the secondary side circuit 2 can be connected to the battery 8 in the illustrated example, and the traveling motor 17 is driven in the example of FIG. In the example 3, power is supplied to the other loads 9. In the figure, 18 is a converter for converting alternating current to direct current (a rectifier or smoothing section described later), 19 is an inverter for converting direct current to alternating current, and in the secondary side circuit 2 of FIG. 3, 20 is for parallel resonance. Capacitor.
The primary coil 12 and the secondary coil 4 have, for example, a flat and substantially flat structure of a multi-turn turn method.

The mutual induction effect of electromagnetic induction is as follows. During power feeding, an induced electromotive force is generated in the secondary coil 4 by forming a magnetic flux in the primary coil 12 between the primary coil 12 and the secondary coil 4 corresponding to each other, so that the primary coil 12 changes to the secondary coil 4. Supplying electric power is publicly known.
That is, a magnetic field is generated around the primary coil 12 by applying and energizing an alternating current of, for example, several kHz to 100 kHz from the power supply 13 to the primary coil 12 of the primary circuit 11 as a feeding alternating current and an exciting current. Magnetic flux is formed in a direction perpendicular to the coil surface.
And the magnetic flux formed in this way penetrates the secondary coil 4 of the secondary side circuit 2, and an induced electromotive force is produced | generated and a magnetic field is formed. In this way, electric power is transmitted and received using the induced magnetic field. It is also possible to supply power of about 1 kW to several kW or more, and about several tens kW to several hundred kW.
In the non-contact power feeding apparatus 10, a magnetic path of magnetic flux is formed between the primary coil 12 and the secondary coil 4 based on such mutual induction action of electromagnetic induction, and the primary coil 12 and the secondary coil 4 are electromagnetically coupled. Combined, non-contact power feeding is performed. In the secondary side circuit 2, the alternating current from the secondary coil 4 is converted into a direct current and supplied to the battery 8.
About the non-contact electric power feeder 10, the general description is as above.

<< Outline of the Invention >>
Hereinafter, the contactless power supply device 10 with overvoltage protection according to the present invention will be described with reference to FIGS. 1 and 2. First, the outline of the present invention is as follows.
In the non-contact power feeding device 10 with overvoltage protection of the present invention, an overvoltage protection unit 21 is provided between the rectification unit 5 and the smoothing unit 6 in the secondary circuit 2. When the overvoltage protection unit 21 detects occurrence of overvoltage in the secondary side circuit 2, the secondary side circuit 2 and the secondary coil 4 are short-circuited to protect the secondary side circuit 2.
The overvoltage protection unit 21 has a circuit configuration including the following detection means 22, amplification means 23, short-circuit means 24, backflow prevention means 25, and the like.
That is, the detecting unit 22 including, for example, a Zener diode 26 that detects an overvoltage in the smoothing unit 6 as a breakdown voltage, the amplifying unit 23 that amplifies the current from the Zener diode 26, and the gate current from the amplifying unit 23 are turned on. The short-circuit means 24 comprising a protective thyristor 27 that implements a short circuit immediately after the rectifier 5 and the backflow prevention means comprising a back-flow prevention diode 28, for example, prevent current backflow from the smoothing section 6 to the protective thyristor 27 in the event of a short circuit. 25.
The outline of the present invention is as described above. Hereinafter, the present invention will be described in detail.

<< About the secondary circuit 2 >>
First, the secondary side circuit 2 of this non-contact electric power feeder 10 is demonstrated. In the secondary side circuit 2, first, the secondary coil 4 is connected to the input end of the rectifying unit 5. Then, between the output terminal of the rectifying unit 5 and the input terminal of the battery 8, the overvoltage protection unit 21, the smoothing unit 6, the charging unit 7, and the like have a circuit configuration that is connected in parallel from the rectifying unit 5 side in order. The circuit configuration is also connected in parallel with each other in order.
Further, the protective thyristor 27 of the short-circuiting means 24, the photothyristor 29 of the amplifying means 23, the Zener diode 26 of the detecting means 22 constituting the overvoltage protection part 21 are also arranged between the rectifying part 5 and the smoothing part 6 from the rectifying part 5 side. The circuits are connected in parallel, and the circuit configuration is also connected in parallel with each other.
The backflow prevention diode 28 of the backflow prevention means 25 is connected in series between the plus output terminal of the rectifying unit 5 and the plus input terminal of the smoothing unit 6.

First, the rectifying unit 5 is composed of a bridge full-wave rectifier circuit using a diode in the illustrated example, and its input end is connected in parallel to the secondary coil 4, and converts alternating current from the secondary coil 4 into direct current including pulsation. To do.
In the illustrated example, the smoothing unit 6 includes three capacitors connected in parallel to each other. The smoothing unit 6 is connected in parallel to the output terminal of the rectifying unit 5 via the overvoltage protection unit 21 and is included in the output voltage of the rectifying unit 5. Reduce the amount of pulsation to obtain a stable direct current.
The charging unit 7, which is sometimes called a DC power source, is connected in parallel to the output terminal of the smoothing unit 6, and performs a constant DC voltage or a low voltage in preparation for charging the battery 8. In addition, a capacitor may be used as such a charging unit 7.
The battery 8 is connected in parallel to the output terminal of the charging unit 7 and is made of, for example, a lead storage battery, and supplies power to a load 9 connected in parallel to the output terminal.
The secondary side circuit 2 is as described above.

<< Overvoltage protection unit 21 >>
Next, the overvoltage protection unit 21 provided in the secondary side circuit 2 will be described. First, the short-circuit means 24 of the overvoltage protection unit 21 is adjacently connected in parallel immediately after the output terminal of the rectification unit 5 of the secondary circuit 2, and a protection thyristor 27 is used in the illustrated example.
The thyristor 27 has an anode terminal connected to a connection point with the positive output terminal side of the rectification unit 5 and a cathode terminal connected to a connection point with the negative output terminal side of the rectification unit 5.
Then, the current from the amplifying means 23 is turned on using the gate current and trigger as a trigger, and the anode terminal and the cathode terminal are turned on in the forward direction and conducted. Accordingly, the secondary circuit 2 and the secondary coil 4 are short-circuited by short-circuiting at a non-smooth voltage portion having a pulsation immediately after the rectifying unit 5. The short-circuit means 24 in the illustrated example performs the short-circuit using the protective thyristor 27 as described above.

On the other hand, the detection means 22 of the overvoltage protection unit 21 is connected in parallel immediately before the input terminal of the smoothing unit 6 of the secondary side circuit 2, and a zener diode 26 is used in the illustrated example.
The Zener diode 26 has a cathode terminal connected to a connection point with the positive input terminal side of the smoothing unit 6, and an anode terminal connected to a connection point with the negative input terminal side of the smoothing unit 6.
The Zener diode 26 detects the overvoltage in the smoothing unit 6 as a breakdown voltage. That is, when an overvoltage is generated with respect to a smoothed voltage free from pulsation, this is turned on in the reverse direction as a breakdown voltage (zener voltage) to conduct, and the occurrence of an overvoltage in the secondary circuit 2 is detected. The detection means 22 in the illustrated example detects the overvoltage using the Zener diode 26 in this way.

Since it is difficult to directly use the current from the Zener diode 26 thus conducted as the gate current of the protection thyristor 27 (because it is a high voltage, it cannot be made a high current and is insufficient as a trigger for the protection thyristor 27). In the illustrated overvoltage protection unit 21, an amplifying means 23 is provided.
The amplifying means 23 includes a light emitting diode (LED) 30 connected in series to the anode terminal side of the Zener diode 26 and a photothyristor 29 connected in parallel between the protective thyristor 27 and the Zener diode 26. .
The light emitting diode 30 is connected in series to the Zener diode 26 with its anode terminal facing the anode terminal side of the Zener diode 26. The photothyristor 29 is connected in parallel with its anode terminal facing the connection point with the positive input terminal side of the smoothing unit 6 and with its cathode terminal facing the connection point with the negative input terminal side of the smoothing unit 6. .
Therefore, when the light emitting diode 30 emits light due to the conduction of the Zener diode 26, the light emission is incident on the gate electrode of the photothyristor 29 and becomes a trigger. Then, the photothyristor 29 is turned on in the forward direction, and the current becomes the gate current and trigger of the protective thyristor 27 of the short-circuit means 24 described above. In the figure, reference numeral 31 denotes a thermistor for temperature compensation.

The overvoltage protection unit 21 is provided with backflow prevention means 25. That is, in the secondary circuit 2, the backflow prevention means 25 is provided in order to prevent the current from flowing back and rushing into the protective thyristor 27 of the short circuit means 24 from the smoothing section 6 side when the short circuit is performed. It has been.
In the illustrated example, a backflow prevention diode 28 is used as such backflow prevention means 25. The backflow prevention diode 28 is connected in series between a connection point between the short-circuit means 24 and the anode terminal side of the protective thyristor 27 and a connection point between the photothyristor 29 of the amplification means 23 and the anode terminal side. The backflow prevention diode 28 has an anode terminal directed to the protective thyristor 27 side and a cathode terminal directed to the photothyristor 29 side.
Accordingly, the current is allowed to flow only in the forward direction from the anode terminal to the cathode terminal by the rectifying action of the diode 28 and the flow in the reverse direction is prevented, so that the current flows from the smoothing unit 6 side to the protective thyristor 27. Is prevented.
The overvoltage protection unit 21 is as described above.

<< About the delay means 32 >>
Next, the delay means 32 will be described. The overvoltage protection unit 21 is provided with delay means 32. This delay means 32 enables the overvoltage protection unit 21 to operate after the secondary side circuit 2 has started up, that is, with a slight delay in timing at the start of power feeding.
The delay means 32 in the illustrated example includes a control battery 33 connected in parallel to the input end of the charging unit 7, a relay coil 34 that can be energized by the control battery 33, and a parallel connection between the control battery 33 and the relay coil 34. The circuit configuration includes a connected capacitor 35 and a resistor 36 connected in series.
The normally open relay contact 37 opened and closed by the relay coil 34 is the anode terminal of the Zener diode 26 of the detection means 22 of the overvoltage protection unit 21 described above, and in the illustrated example, the cathode terminal of the light emitting diode 30 of the amplification means 23. And the connection point of the smoothing unit 6 to the negative input terminal side.

Since such a delay means 32 is provided, when power feeding from the primary side circuit 11 of the non-contact power feeding device 10 to the secondary side circuit 2 is started, that is, when the power supply 13 is turned on, the following It becomes like this.
First, the charging unit 7 and the battery 8 of the secondary side circuit 2 are started up and started, and consumption of the supplied power is started. The delay means 32 then delays the timing for a predetermined time (for example, shifting the timing by about 0.3 seconds), and the overvoltage protection unit 21, particularly the Zener diode 26 of the detection means 22 can be activated.
That is, the delay means 32 requires a predetermined time from the start of power supply until the relay coil 34 is excited by charging and energizing the control battery 33, the capacitor 35, the resistor 36, and the like.
Therefore, the zener diode 26 of the detection means 22 of the overvoltage protection unit 21 is energized after the predetermined time has elapsed (for example, after about 0.3 seconds), the normally open relay contact 37 is closed or turned on. It becomes possible. Accordingly, the detection means 22 can be operated.
In this way, the overvoltage protection unit 21 can operate with a delay with respect to the secondary circuit 2. That is, overvoltage protection by the overvoltage protection unit 21 is prohibited until the charging unit 7 and the like of the secondary side circuit 2 are started up.
The delay means 32 is as described above.

<< About the power supply 13 off in case of short circuit >>
Next, the power supply 13 off of the primary side circuit 11 at the time of short circuit will be described. When the secondary circuit 2 is short-circuited by the overvoltage protection unit 21, the non-contact power feeding device 10 includes a detection unit 38 that detects a current change or a voltage change of the primary circuit 11 based on the short circuit, A control unit 39 that turns off the power supply 13 of the primary circuit 11 based on the detection has a circuit configuration.
That is, when the secondary coil 4 is short-circuited by the overvoltage protection unit 21, the current and voltage of the primary coil 12 and the primary side circuit 11 also change suddenly. Therefore, in the illustrated example, the alternating current change of the primary circuit 11 is transformed into a proportional secondary current change by the detection unit 38 using the CT coil. The AC voltage change may be transformed into a proportional secondary voltage change by the detection unit 38 using a transformer.
And the control part 39 discriminate | determines the presence or absence of the short circuit in the secondary side circuit 2 based on such a secondary current change and secondary voltage change input via the rectifier 40. FIG. That is, the detected current value or voltage value is compared with a preset current value or voltage value to determine whether or not there is a short circuit.
When it is determined that there is a short circuit, an off signal is output to the switch portion of the power supply 13 of the primary side circuit 11 to turn off the power supply 13. As such a control unit 39, a microcomputer loaded with a dedicated program, a sequencer using a data processing comparator, or the like is used.
Further, an alarm signal may be sent from the control unit 39 to the alarm unit, so that an alarm indicating that an overvoltage abnormality has occurred and short-circuited is given to the operator by an alarm unit display or buzzer sound.
The power supply 13 is turned off at the time of the short circuit as described above.

《Action etc.》
The contactless power supply device 10 with overvoltage protection of the present invention is configured as described above. Therefore, it becomes as follows.
(1) In the non-contact power feeding device 10, the secondary coil 4 of the secondary circuit 2 on the moving body side such as the vehicle B has an air gap G with respect to the primary coil 12 of the primary circuit 11 on the ground A side. In the corresponding position, power is supplied (see FIG. 4).

(2) That is, at the time of power feeding, in the primary side circuit 11, an exciting current is passed from the power source 13 to the primary coil 12 as a feeding AC.
Accordingly, a magnetic flux is formed in the primary coil 12, and a magnetic path of the magnetic flux is formed in the air gap G between the primary coil 12 and the secondary coil 4. In this way, the primary coil 12 and the secondary coil 4 are electromagnetically coupled, and the magnetic flux passes through the secondary coil 4, so that an induced electromotive force is generated in the secondary coil 4.
In the non-contact power feeding apparatus 10, electric power is supplied from the primary side circuit 11 to the secondary side circuit 2 by such mutual induction action of electromagnetic induction (see FIGS. 1, 2, and 3). .

(3) In the secondary side circuit 2, the alternating current from the secondary coil 4 is converted to direct current including the pulsation by the rectification unit 5, and after passing through the overvoltage protection unit 21, the pulsation is reduced by the smoothing unit 6. .
Accordingly, the smoothed direct current is made constant voltage or low voltage by the charging unit 7 and supplied to the battery 8. Electric power is supplied from the charged battery 8 to the load 9 or the like as necessary (see FIGS. 1, 2, 3 and the like).

(4) Now, the non-contact electric power feeder 10 of this invention is provided with the overvoltage protection part 21 in the secondary side circuit 2.
The overvoltage protection unit 21 includes a detection unit 22 that detects occurrence of overvoltage, an amplification unit 23 that amplifies the current, and a short circuit unit 24 that performs a short circuit. Therefore, when the overvoltage protection unit 21 detects the occurrence of overvoltage in the secondary side circuit 2, the overvoltage protection unit 21 short-circuits and protects it (see FIGS. 1 and 2).
That is, when an overvoltage occurrence, that is, an abnormal rise in DC voltage is detected in the secondary side circuit 2, the secondary side circuit 2 and the secondary coil 4 are short-circuited. 5, the smoothing unit 6, the charging unit 7, the load 9 and the like are prevented from being damaged or burnt by application of overvoltage, and are protected.

(5) Now, in this overvoltage protection part 21, an overvoltage is detected and a short circuit is implemented as follows.
That is, the detecting means 22 of the overvoltage protection unit 21, for example, the Zener diode 26 is connected in parallel before the smoothing unit 6 of the secondary circuit 2, and detects the presence or absence of occurrence of overvoltage for the smoothed voltage without pulsation. (See FIG. 2).
That is, an overvoltage is detected for a voltage that matches the input voltage to the charging unit 7 or the like of the secondary side circuit 2. In this way, the detection means 22 of the overvoltage protection unit 21 detects and grasps an overvoltage for a voltage that matches the secondary side circuit 2 such as the charging unit 7 and does not have an excess or deficiency. And the short circuit means 24 of the overvoltage protection part 21 implements a short circuit based on such a detection.

(6) When the short circuit is performed, there is a risk of backflow current flowing from the smoothing unit 6 side to the short circuit means 24 of the overvoltage protection unit 21, for example, the protection thyristor 27, which is avoided by the backflow prevention means 25. (See FIG. 1).
That is, in the secondary circuit 2, the backflow prevention diode 28 is connected in series as the backflow prevention means 25 between the protection thyristor 27 of the overvoltage protection unit 21 and the smoothing unit 6. Therefore, the backflow current, the inrush current, and the inflow current from the smoothing section 6 side to the protection thyristor 27 at the time of a short circuit are blocked.

(7) Further, the overvoltage protection unit 21 is provided with delay means 32. Therefore, when the power supply is started by the delay means 32, the secondary side circuit 2 such as the charging unit 7 and the battery 8 rises and starts up, and for example, after about 0.3 seconds, the timing is delayed to protect the overvoltage. The part 21 becomes operable (see FIG. 2). That is, the detection means 22 such as the Zener diode 26 of the overvoltage protection unit 21 can be operated.
As a result, the amplifying means 23 such as the light emitting diode 30 and the photothyristor 29 are also operable, the gate current to the protective thyristor 27 is enabled, and the short circuit means 24 is also operable.
In the secondary circuit 2 at the start of power supply, before the charging unit 7 and the like starts up and starts up, the supplied power is not consumed and the voltage inevitably rises. It is no longer necessary to grasp the above, and it is possible to avoid performing a short circuit.
The overvoltage protection unit 21 can perform a short circuit as expected only after the secondary circuit 2 such as the charging unit 7 has started up and when an original overvoltage has occurred.

(8) In this contactless power supply device 10, when a short circuit is implemented by the overvoltage protection unit 21, the power supply 13 is immediately turned off by the detection unit 38 and the control unit 39 attached to the primary circuit 11. (See FIG. 1).
That is, when the secondary circuit 2 is short-circuited, the current and voltage of the primary circuit 11 change based on the short circuit. Therefore, when such a current change or voltage change is detected by the detection unit 38 attached to the primary circuit 11, and the control unit 39 determines that the short circuit is performed based on the detection, the primary circuit 11 is turned off.
Thus, power supply is stopped reliably and immediately with a simple configuration.
As for the action, it is as above.

1 Non-contact power feeding device (prior art)
2 Secondary circuit 3 Overvoltage protector (conventional technology)
4 Secondary coil 5 Rectifying unit 6 Smoothing unit 7 Charging unit 8 Battery 9 Load 10 Non-contact power feeding device (present invention)
DESCRIPTION OF SYMBOLS 11 Primary side circuit 12 Primary coil 13 Power supply 14 Choke coil 15 Capacitor 16 Capacitor 17 Motor 18 Converter 19 Inverter 20 Capacitor 21 Overvoltage protection part (this invention)
DESCRIPTION OF SYMBOLS 22 Detection means 23 Amplification means 24 Short circuit means 25 Backflow prevention means 26 Zener diode 27 Protection thyristor 28 Backflow prevention diode 29 Photothyristor 30 Light emitting diode 31 Thermistor 32 Delay means 33 Control battery 34 Relay coil 35 Capacitor 36 Resistance 37 Relay contact 38 Detection 39 Control unit 40 Rectifier A Ground B Vehicle C Power supply stand G Air gap

Claims (5)

A non-contact power feeding device that supplies electric power from a primary coil of a primary circuit to a secondary coil of a secondary circuit based on the mutual induction action of electromagnetic induction, leaving an air gap,
For the secondary side circuit, an overvoltage protection unit is provided between the rectification unit and the smoothing unit. When the overvoltage protection unit detects an overvoltage occurrence in the secondary side circuit, the secondary side circuit and 2 A non-contact power feeding device with overvoltage protection, wherein a secondary coil is short-circuited to protect the secondary side circuit.   2. The overvoltage protection unit according to claim 1, wherein the overvoltage protection unit includes a detection unit that detects an overvoltage in the smoothing unit, a short circuit unit that performs a short circuit based on detection by the detection unit, and a current reverse flow from the smoothing unit to the short circuit unit. A non-contact power feeding device with overvoltage protection, characterized by comprising a backflow prevention means for preventing the backflow. In Claim 2, the overvoltage protection unit, a Zener diode as the detection means for detecting the overvoltage in the smoothing unit as a breakdown voltage,
Amplifying means for amplifying the current from the zener diode; and a protection thyristor as the short-circuit means for turning on based on the gate current from the amplifying means and for performing a short circuit immediately after the rectifying unit;
A non-contact power feeding device with overvoltage protection, comprising: a backflow prevention diode as backflow prevention means for preventing backflow of current from the smoothing portion side to the protection thyristor during a short circuit.   3. The overvoltage protection unit according to claim 2, further comprising a delay unit, and the delay unit enables the overvoltage protection unit to operate after the secondary circuit starts up when starting power feeding. A non-contact power feeding device with overvoltage protection. The detection circuit according to claim 1, wherein when the secondary circuit is short-circuited, a detection unit that detects a current change or a voltage change of the primary circuit based on the short circuit, and the primary circuit based on the detection of the detection unit The non-contact electric power feeder with overvoltage protection characterized by the above-mentioned. The control part which turns off the power supply of is provided.

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