JP4265614B2 - Secondary power receiving circuit for contactless power supply equipment - Google Patents

Description

  The present invention relates to a secondary power receiving circuit of a contactless power supply facility, and more particularly to a protection circuit thereof.

An example of a secondary power receiving circuit of a contactless power supply facility provided with a conventional protection circuit is disclosed in Patent Document 1.
In this patent document 1, the secondary power receiving circuit of the contactless power supply equipment is inducted with a pickup coil provided opposite to the primary induction line through which a high-frequency current flows, and the pickup coil connected to the pickup coil. A capacitor that forms a resonance circuit that resonates with the frequency of the line, a rectifier circuit connected to the capacitor, an output terminal of the rectifier circuit and a load, a constant voltage that is controlled to a reference voltage and supplied to the load It consists of a control circuit.

  The protection circuit for the secondary power receiving circuit includes a heat sensitive wire having open ends at both ends of the resonance circuit including the pickup coil and the capacitor, and a circuit between the constant voltage control circuit and the load. Install a protector, connect the circuit protector's trip coil and surge absorber in series at both ends of the load, wind a nichrome wire around the heat sensitive wire, and fix both ends of the nichrome wire through the auxiliary contacts of the circuit protector. It is connected to the output terminal of the voltage control circuit. For example, the heat-sensitive wire is formed by coating a pair of conductors made of a non-magnetic phosphor bronze round wire with an insulator made of heat-sensitive thermoplastic, and twisting the pair of conductors coated with these insulators. It is constructed by covering the tape and sheath on it, and when the ambient temperature reaches a certain temperature, the insulator softens and the twisted pair of conductors cause a spring action to cause a short circuit ing.

With this protection circuit configuration, when an abnormality occurs in the resonant circuit, rectifier circuit, or constant voltage control circuit and an abnormal voltage occurs, a voltage that exceeds the maximum allowable voltage is applied to the surge absorber, current flows, and the load An abnormal voltage is prevented from being applied, and at the same time, a current flows through the tripping coil of the circuit protector to operate the circuit protector, and the power supply side (resonance circuit side) is disconnected from the load, thus reliably supplying power to the load. Is cut off, the load voltage becomes zero, and an abnormal voltage is prevented from being applied to the load. At this time, the auxiliary contact of the circuit protector is turned on, and the nichrome wire is energized, and thus the nichrome wire generates heat, and the heat sensitive wire is heated by this heat generation. A pair of twisted conductors cause a spring action to short-circuit, and both ends of the pickup coil are short-circuited. Therefore, the power supply to the constant voltage control circuit and the load is cut off, and an abnormal voltage is prevented from being applied to these circuits.
JP-A-11-341713

  However, in the protection circuit for the secondary power receiving circuit of the conventional contactless power supply equipment, if an abnormal voltage occurs due to an abnormality in the resonance circuit, the heat sensitive wire is heated and the insulator is softened. In addition, there is a problem that a specific odor is generated due to the generation of organic gas, and since it is necessary to replace the heat sensitive line in addition to the resonance circuit etc. where abnormality occurred, it takes time to recover was there.

  Also, as a protection circuit for the secondary power receiving circuit of the non-contact power feeding equipment, it is of course possible to provide a circuit breaker for wiring that interrupts the circuit in series with the pickup coil, instead of short-circuiting both ends of the pickup coil. However, in Patent Document 1, since the secondary power receiving circuit of the contactless power supply facility is formed by a parallel resonant circuit, when a circuit breaker for wiring is provided in the parallel resonant circuit portion, the current flowing through the load is supplied to the circuit breaker. Therefore, a large and expensive circuit breaker is required, and therefore a circuit breaker is rarely used.

  In Patent Document 1, the secondary power reception circuit is formed by a parallel resonance circuit, but can also be formed by a series resonance circuit. In this way, when the secondary power receiving circuit of the contactless power supply facility is configured with a series resonance circuit and the resonance circuit is rectified and connected to the load, the current flowing through the load and the current flowing through the series resonance circuit are the same. Therefore, even if a circuit breaker for wiring is provided in the series resonance circuit portion, the current capacity required for the circuit breaker for wiring may be small. However, if an abnormal voltage is generated in the constant voltage control circuit, a large current flows through the series resonant circuit. Therefore, a high withstand voltage (di / dt) is applied to the switching contact of the circuit breaker that interrupts this. There was a problem that it was necessary to select a large and expensive circuit breaker. Instead of the parallel resonant circuit, a plurality of series resonant circuits are formed, and these series resonant circuits are connected in series via the switching circuit, and the switching circuit sets the multiple series resonant circuits in a series state or a parallel state to the load. When adjusting the applied voltage, if a plurality of series resonant circuits remain connected in series due to some abnormality and a high voltage is continuously applied to the constant voltage control circuit, etc., components such as elements of the constant voltage control circuit In order to prevent this, there is a similar problem when a circuit breaker for wiring is provided in the series resonance circuit portion.

  Therefore, the present invention provides an inexpensive non-contact power receiving circuit formed by a series resonance circuit that can protect the circuit when an abnormality occurs in the resonance circuit or the like and can shorten the time to recovery. An object of the present invention is to provide a secondary power receiving circuit of a contact power supply facility.

  In order to achieve the above-described object, the invention described in claim 1 of the present invention is provided with a plurality of pickup coils that are opposed to the primary side induction line through which a high-frequency current flows and in which an electromotive force is induced from the induction line. A resonance capacitor is connected to each pickup coil in series to form a resonance circuit that resonates at the frequency of the induction line. Further, these resonance circuits are connected in series, and each resonance circuit is generated by the resonance circuit. A rectifying circuit for rectifying the voltage is provided, switching means for connecting the rectifying circuits in parallel, supplying power to a load whose power consumption fluctuates, and connecting or opening the resonance circuits is provided. Voltage control means for controlling the output voltage applied to the load by providing a connection state or an open state between the resonance circuits by providing a predetermined voltage. When applied, an element that conducts current and a circuit breaker that operates when the current flowing through the element reaches a predetermined current value and interrupts the current are connected in series, and the series circuit is connected in parallel. Connected between the output terminals of the rectifier circuit, connected in series with the switching means, and connected to the output contact of the circuit breaker that is opened when the circuit breaker for the wiring breaks the current. When the current is cut off, the resonance circuits are opened.

  According to the above configuration, when an abnormality occurs in each resonance circuit or switching means or each rectifier circuit and an abnormal voltage higher than a predetermined voltage is applied to the element, a current flows through the element, and the circuit breaker for wiring is caused by the current. When operating, the circuit breaker interrupts the current flowing through the element and prevents the element from being destroyed, and at the same time, the output contact between the resonance circuits is opened, and each resonance circuit is disconnected. The rectifier circuits are connected in parallel, the voltage applied to the voltage control means and the load is reduced, and an abnormal voltage is prevented from being applied to the voltage control means and the load.

  The invention according to claim 2 is the invention according to claim 1, wherein the switching means includes a transformer in which a primary winding is connected in series between the resonance circuits, and the transformer. A rectifier connected to the secondary winding of the rectifier and switching means connected between the output terminals of the rectifier, the voltage control means by connecting the switching means to the open state The output voltage applied to the load is controlled, and the output contact of the circuit breaker for wiring is connected in series between the secondary winding of the transformer and the rectifier It is.

  According to the above configuration, when an abnormality occurs in each resonance circuit or switching means or each rectifier circuit and an abnormal voltage higher than a predetermined voltage is applied to the element, a current flows through the element, and the circuit breaker for wiring is caused by the current. When operating, the circuit breaker interrupts the current flowing through the element and prevents the element from being destroyed. At the same time, the secondary side of the transformer is opened by the output contact, and each resonance circuit is disconnected. The rectifier circuits are connected in parallel, the voltage applied to the voltage control means and the load is reduced, and the abnormal voltage is prevented from being applied to the voltage control means and the load. Thus, by connecting the output contact of the circuit breaker in series with the secondary winding of the transformer, all of the plurality of resonance circuits are disconnected by one output contact.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the element is formed of a Zener diode, and the circuit breaker for wiring limits a current flowing through the Zener diode. It is characterized by doing.

  According to the above configuration, the current starts to flow through the Zener diode, and when the current value reaches a predetermined current value, the circuit breaker operates to limit the current value flowing through the Zener diode, thereby protecting the Zener diode.

  When the secondary side power receiving circuit of the contactless power supply facility of the present invention has an abnormality in each resonance circuit or switching means or each rectifier circuit, the resonance circuit is opened by the output contact of the circuit breaker for wiring. The resonant circuit is disconnected, and the rectifier circuit and the rectifier circuit are connected in parallel, so that the voltage applied to the voltage control means and the load can be reduced, and an abnormal voltage is applied to the voltage control means and the load. Can be prevented from being applied, and the circuit can be protected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit configuration diagram of a secondary power receiving circuit of a contactless power supply facility according to an embodiment of the present invention.

  As shown in FIG. 1, the secondary power receiving circuit of the contactless power supply facility is a first in which an electromotive force is induced from the induction line 1 facing the primary side induction line 1 that flows a high-frequency current I of about 10 kHz, for example. A pickup coil 2A and a second pickup coil 2B are provided, and an electromotive force induced in the first pickup coil 2A and the second pickup coil 2B is supplied to a load 10 whose power consumption varies.

This secondary side power receiving circuit is connected in series to each of the pickup coils 2A and 2B, respectively, and forms a first capacitor (resonance capacitor) 3A and a second capacitor that form resonance circuits 4A and 4B that resonate at the frequency of the induction line 1 (series). A switching circuit (an example of switching means) 5 that is connected in series between the capacitor (resonance capacitor) 3B and each of the resonance circuits 4A and 4B and that connects or disconnects the resonance circuits 4A and 4B, and a resonance circuit 4A and 4B are connected in parallel to each other, rectifying circuits 6A and 6B for rectifying voltages generated by the resonance circuits 4A and 4B, and connected in parallel to the output side of the rectifying circuits 6A and 6B, and connected to the load 10. biopsies voltage capacitor (output capacitor) 8, to control the output voltage V _DC applied to the load 10 by controlling the switching circuit 5, that is, the output voltage V _DC And, the output voltage V _DC is a predetermined voltage or lower, the resonance circuit 4A by the switching circuit 5, between 4B and a connected state, to the resonant circuit 4A, between 4B and opened by the switching circuit 5 exceeds the predetermined voltage A voltage controller (an example of voltage control means) 11 is configured.

The switching circuit 5 includes a transformer 21 in which a primary side winding is connected in series between the resonance circuits 4A and 4B, and a rectifier in which input ends are connected to both ends of the secondary side winding of the transformer 21. 22, an output adjustment transistor (an example of a switching means) 23 in which a collector and an emitter are connected between both output terminals of the rectifier 22, and a plus-side output terminal of the rectifier 22 and a collector of the output adjustment transistor 23. It is composed of a diode 24 having an anode connected to the connection point and a cathode connected to one end of the load 10. The voltage controller 11 detects the output voltage V _DC, the output voltage V _DC is the output adjusting transistor 23 when more than the predetermined voltage is set to ON (connected state), the output adjusting transistor 23 exceeds a predetermined voltage Is off (open state).

  Then, the protection circuit for the secondary power receiving circuit is configured such that the Zener diode 31 that is an element through which a current flows when a predetermined voltage is applied, and the current flowing through the Zener diode 31 has a preset predetermined current value. A circuit breaker 32 for automatically interrupting this current is connected in series, this series circuit is connected in parallel with the output side of the rectifier circuits 6A and 6B, and the resonance circuit 4A and the switching circuit 5 (the primary side winding of the transformer 21). The output contact 33 of the circuit breaker 32 is connected in series with the line). The cathode of the Zener diode 31 is connected to the positive side of the output of the rectifier circuits 6A and 6B, and the anode is connected to the power supply side terminal 34 of the circuit breaker 32 as shown in FIG. The load side terminal 35 is connected to the minus side of the outputs of the rectifier circuits 6A and 6B. The output contact 33 of the wiring breaker 32 is connected to the auxiliary connection terminal 36 of the wiring breaker 32, and is connected in series between the resonance circuit 4 </ b> A and the switching circuit 5 via the auxiliary connection terminal 36. ing. The output contact 33 is always in a connected state, and is opened when the wiring breaker 32 is automatically cut off by a predetermined current.

  The breakdown voltage of the Zener diode 31 is set in accordance with the lowest maximum allowable voltage among the maximum allowable voltages of the voltage capacitor 8, the load 10 and the voltage controller 11, and the predetermined circuit breaker 32 operates. The current value is set to a current value that can be protected by limiting the current flowing through the Zener diode 31 (that can prevent destruction).

Below, the effect | action in the structure of the said secondary side power receiving circuit is demonstrated.
For example, when a high frequency current I of about 10 kHz is supplied to the induction line 1, an induced electromotive force is generated in the pickup coils 2 </ b> A and 2 </ b> B by the magnetic flux generated in the induction line 1, and the induction generated in the pickup coils 2 </ b> A and 2 </ b> B. The electromotive force is rectified as a predetermined voltage by the rectifier circuits 6A and 6B.

When the load 10 consumes predetermined power consumption in the normal load state, the output voltage _VDC is equal to or lower than the predetermined voltage, the output regulator transistor 23 is turned on by the voltage controller 11, and the resonance circuits 4A and 4B are connected in series. The voltage obtained by adding the output voltages of the rectifier circuits 6A and 6B is applied to the load 10 (the voltage obtained by adding the output voltages of the rectifier circuits 6A and 6B charges the voltage capacitor 8 and is supplied to the load 10) )

Here, when the load 10 decreases and the output voltage V _DC increases, the voltage controller 11 turns off the output adjustment transistor 23 when determining that the increased output voltage V _DC exceeds a predetermined voltage. Thus, when the load 10 is in a light load state, when the output adjustment transistor 23 is turned off, the resonance circuits 4A and 4B are disconnected, and the rectifier circuit 6A and the rectifier circuit 6B are connected in parallel. Thus, the voltage applied to the load 10 is reduced to about a half. Then, the output voltage V _DC decreases, and the output voltage V _DC is maintained at a predetermined voltage.

  Also, an abnormality occurs in one or both of the resonance circuits 4A and 4B or the rectifier circuits 6A and 6B, or the switching circuit 5, and an abnormal voltage exceeding the breakdown voltage of the Zener diode 31 is applied to both ends of the Zener diode 31. Then, a current flows through the Zener diode 31 and when the current exceeds a predetermined current set in the circuit breaker 32, the circuit breaker 32 automatically shuts off the current flowing through the Zener diode 31. The zener diode 31 is prevented from being destroyed, and at the same time, the output contact 33 opens the resonance circuit 4A and the switching circuit 5 (primary winding of the transformer 21), and the resonance circuits 4A and 4B. The rectifier circuit 6A and the rectifier circuit 6B are connected in parallel and are applied to the voltage controller 11, the voltage capacitor 8 and the load 10. That voltage drops, the voltage controller 11, an abnormal voltage to a voltage capacitors 8 and the load 10 is prevented from being applied.

  At this time, the large current flowing between the resonance circuits 4A and 4B is not instantaneously interrupted by the wiring circuit breaker 32, but continues via the rectifier circuits 6A and 6B connected to the resonance circuits 4A and 4B, respectively. Therefore, a high voltage (di / dt) is not generated at the output contact 33 of the circuit breaker 32 for wiring. Since the resonance circuit current that flows into the voltage capacitor (output capacitor) 32 only when the output contact 33 of the circuit breaker 32 is open is a very short amount of energy, the voltage of the voltage capacitor (output capacitor) 32 is Furthermore, there is no abnormal rise.

  As described above, according to the present embodiment, it is possible to prevent an abnormal voltage from being applied to the voltage controller 11, the voltage capacitor 8, and the load 10 when an abnormal voltage is generated in the resonance circuits 4A, 4B and the like. In addition, it is possible to avoid the possibility that the elements forming the voltage controller 11 and the voltage capacitor 8 are broken, to avoid the possibility of damaging the load 10, and to protect the circuit. Further, since the abnormality of the secondary side power receiving circuit is processed internally, other normal secondary side circuits can continue the operation without affecting the induction line 1.

  Further, when the current flowing through the Zener diode 31 reaches a predetermined current value, the wiring breaker 32 automatically cuts off the current flowing through the Zener diode 31, thereby preventing the Zener diode 31 from being damaged. Moreover, by using the circuit breaker 32 for wiring, the recovery after the automatic disconnection can be facilitated, and the time until the recovery can be shortened. In addition, since a high withstand voltage (di / dt) is not required for the output contact 33 (switch contact) of the circuit breaker 32 for wiring, an inexpensive commercially available circuit breaker can be used for the circuit breaker 32, and abnormality protection is provided. A circuit can be formed at low cost.

  In the present embodiment, the output contact 33 of the circuit breaker 32 for wiring is connected in series between the resonance circuit 4A and the switching circuit 5 (primary winding of the transformer 21). As described above, the output contact 33 may be connected in series between the secondary winding of the transformer 21 and the input side of the rectifier 22. At this time, as shown in FIG. 3, a resonance circuit 4C formed of a third pickup coil 2C and a third capacitor (resonance capacitor) 3C is further added to the resonance circuits 4A and 4B and connected in series, and the transformer 21 Are connected in a state of being insulated between the resonance circuits 4 (between the resonance circuit 4A and the resonance circuit 4B and between the resonance circuit 4B and the resonance circuit 4C). It is effective when That is, when the output contact 33 of one circuit breaker 32 is opened, the resonance circuits 4A, 4B and the resonance circuits 4B, 4C are opened, so that the resonance circuits 4A, 4B, 4C are separated. That is, since all the resonance circuits 4 are separated, even if the number of the resonance circuits 4 increases, the output contact 33 of one wiring breaker 32 can cope with it.

  In the present embodiment, a Zener diode is used as an element for passing a current when a predetermined voltage is applied. However, the Zener diode is not limited to the Zener diode, and the voltage applied to the output capacitor 8 is the maximum allowable voltage. Any element that operates when the voltage exceeds the voltage and operates the circuit breaker 32 for wiring may be used.

It is a secondary side power receiving circuit of the non-contact electric power supply equipment in embodiment of this invention. It is a figure of the circuit breaker for wiring used for the secondary side power receiving circuit of the non-contact electric power supply equipment, (a) is a front view, (b) is a right view. It is a secondary side power receiving circuit of the non-contact electric power supply installation in other embodiment of this invention.

Explanation of symbols

1 Induction line 2A, 2B, 2C Pickup coil 3A, 3B, 3C Capacitor (resonance capacitor)
4A, 4B, 4C Resonant circuit 5 Switching circuit 6A, 6B, 6C Rectifier circuit 8 Voltage capacitor (output capacitor)
10 Load 11 Voltage controller (voltage control means)
21 Transformer 22 Rectifier 23 Output adjustment transistor (switching means)
31 Zener diode 32 Circuit breaker for wiring 33 Output contact of circuit breaker for wiring

Claims (3)

A plurality of pickup coils that are opposed to the primary side induction line through which high-frequency current flows and in which an electromotive force is induced from the induction line,
A resonance capacitor is connected in series to each pickup coil to form a resonance circuit that resonates at the frequency of the induction line. Further, these resonance circuits are connected in series, and voltages generated by the resonance circuits in the resonance circuits, respectively. A rectifier circuit is provided to rectify the current, and these rectifier circuits are connected in parallel to supply power to a load whose power consumption fluctuates.
Provided a switching means for connecting or opening each of the resonance circuits,
By providing the voltage control means for controlling the output voltage applied to the load by controlling the switching means to connect or open the resonance circuits,
An element that conducts current when a predetermined voltage is applied and a circuit breaker that operates when the current flowing through the element reaches a predetermined current value and interrupts the current are connected in series, and the series circuit is connected to the parallel circuit. Connected between the output terminals of the rectifier circuit connected to
In series with the switching means, an output contact of a circuit breaker that is opened when the circuit breaker interrupts the current is connected, and the resonance circuit is connected between the circuit breakers when the circuit breaker interrupts the current. A secondary-side power receiving circuit of a non-contact power feeding facility, characterized by being in an open state. The switching means is
A transformer in which a primary winding is connected in series between the resonance circuits;
A rectifier connected to the secondary winding of the transformer;
Switching means connected between both output ends of the rectifier,
The voltage control means controls the output voltage applied to the load by connecting the switching means to an open state,
2. The secondary side of the contactless power supply equipment according to claim 1, wherein an output contact of the circuit breaker for wiring is connected in series between a secondary winding of the transformer and the rectifier. Power receiving circuit. 3. The secondary side power receiving of the contactless power supply equipment according to claim 1, wherein the element is formed of a Zener diode, and the circuit breaker for wiring limits a current flowing through the Zener diode. circuit.

Images