JP2012138529A - Secondary side power reception circuit of non-contact power supply facility, and saturable reactor used in secondary side power reception circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary side power reception circuit of a non-contact power supply facility capable of stably supplying power at the voltage required from a load, without depending on a saturation voltage of a saturable reactor that fluctuates because of change in ambient temperature and magnetic characteristic of a magnetic core.SOLUTION: A current circuit 41 is provided in which a saturable reactor 15, consisting of a magnetic core and a primary coil 33 wound on the magnetic core, is connected to a resonance circuit 13, and two bias coils 36 and 37 having the same length and same characteristic are wound on the magnetic core and connected in series for opposite polarities. Here, when a both-end voltage (a voltage applied to a load 18) of an output capacitor 19 comes to be a target voltage or higher that is required by the load 18, a DC bias current flows the bias coils 36 and 37. The saturable reactor 15 is saturated when the bias current flows, and a voltage applied to the load 18 is suppressed to the target voltage required by the load 18.

Description

  The present invention relates to a secondary power receiving circuit of a contactless power feeding facility, and more particularly to a secondary power receiving circuit of a contactless power feeding facility using a saturable reactor.

A configuration of a secondary power receiving circuit of a contactless power supply facility using a conventional saturable reactor is disclosed in Patent Document 1 (FIG. 2).
The secondary-side power receiving circuit disclosed in Patent Document 1 is a power receiving coil in which an electromotive force is induced from the induction line facing an induction line through which a high-frequency current flows, and resonates with the frequency of the induction line together with the power receiving coil. A resonant capacitor that forms a resonant circuit, a core member (magnetic core) that forms an annular magnetic path, a saturable reactor having a coil wound around the core member and connected in parallel to the resonant circuit, and a receiving coil A rectifier circuit is provided for rectifying the output current and outputting it to the load.
Then, by setting the saturation voltage of the magnetic core of the saturable reactor to a voltage required by the load (for example, an allowable upper limit voltage), the resonance voltage of the resonance circuit is changed to the saturation voltage of the magnetic core of the saturable reactor. Therefore, the voltage applied to the load is suppressed to a voltage required by the load.

Japanese Patent No. 4052436 (FIG. 2)

However, the magnetic core of a saturable reactor (ferrite material) usually has a magnetic saturation density that changes depending on the temperature used. Therefore, the saturation voltage fluctuates due to changes in the environmental temperature and self-heating. Alone, it was difficult to stabilize the voltage required by the load.
In addition, since ferrite materials have large variations in individual magnetic characteristics, it is necessary to measure individual characteristics. Depending on this characteristic, it is necessary to change the number of turns of the coil in order to obtain a predetermined saturation voltage. In some cases, it has been difficult to mass-produce a saturable reactor having a predetermined characteristic stably secured.
Further, when the voltage required by the load is changed, it is necessary to change the number of turns of the coil, and there is a problem that it cannot be easily handled.

  Accordingly, the present invention provides a secondary power supply system that can stably supply power at a voltage required by a load without depending on the saturation voltage of a saturable reactor that varies depending on changes in environmental temperature and magnetic characteristics of a magnetic core. It is an object of the present invention to provide a side power receiving circuit and a saturable reactor used in the secondary power receiving circuit.

In order to achieve the above-described object, the invention according to claim 1 of the present invention is fed in a contactless manner from a primary induction line or a primary feeding coil to which a high-frequency current is supplied, and is supplied to a load. A secondary power receiving circuit of a contactless power supply facility for supplying power,
A receiving coil in which an electromotive force is induced from the primary-side induction line or the primary-side feeding coil, and a resonance circuit that is connected in parallel to the receiving coil and resonates with the frequency of the receiving coil and the high-frequency current are formed. A resonant capacitor, a saturable reactor connected to both ends of the resonant circuit, a rectifier circuit that rectifies and outputs a current output from the resonant circuit, and an output terminal of the rectifier circuit in parallel with the load With a connected output capacitor,
The saturable reactor includes a plurality of first magnetic cores, a primary coil that is commonly wound around the plurality of first magnetic cores and connected in parallel to the resonance circuit, and each of the first magnetic cores. A bias coil wound and connected so that electromotive forces cancel each other when a current flows through the primary coil, and the total cross-sectional area of the first magnetic core is a saturation voltage of the entire first magnetic core Is set to be higher than the target voltage required by the load, and when the load voltage becomes equal to or higher than the target voltage, a DC bias current is passed through the bias coil to saturate the first magnetic core. A current circuit is provided.

According to the said structure, there exist the following effects.
First, a description will be given of the operation when the first magnetic core is composed of two pieces, and the bias coil is composed of two first magnetic cores, and no bias current flows through these bias coils.
When the resonance voltage of the resonance circuit is less than the saturation voltage of the first magnetic core of the saturable reactor, the (constant) current output from the resonance circuit is rectified by the rectification circuit and supplied to the load and the output capacitor. The output capacitor is filled. Also, when the load decreases, the voltage across the output capacitor and the resonance voltage of the resonance circuit increase, and when the voltage exceeds the saturation voltage of the first magnetic core, the inductance of the primary coil decreases and current flows rapidly. The resonance voltage of the resonance circuit is suppressed to the saturation voltage of the first magnetic core, and the voltage across the output capacitor, that is, the voltage applied to the load is suppressed to the saturation voltage or less. This is because, in the magnetic hysteresis curve (BH curve) of the magnetic core in FIG. 5A, BH is between + Bm in the first quadrant and -Bm in the third quadrant between the positive and negative cycles. It is understood as a transition state.
At this time, the two bias coils wound around the first magnetic core are connected so that the electromotive forces generated when a current flows through the primary coil cancel each other, that is, with opposite polarities. Since the electromotive forces generated in these bias coils cancel each other and balance, current does not flow through the bias coils, and therefore the primary coil is not affected.

Based on such an operation, the operation when a bias current flows through the two bias coils wound around the two first magnetic cores will be described.
Since the saturation voltage of the first magnetic core varies depending on the temperature of the environment and the magnetic characteristics of the magnetic core, the saturation voltage of the entire first magnetic core is set higher than the target voltage required by the load. The constant voltage control to the target voltage lower than the saturation voltage of the entire first magnetic core is performed using a backup voltage that suppresses the voltage applied to the output capacitor, that is, the voltage across the output capacitor.
That is, when the voltage of the load (the voltage across the output capacitor) becomes equal to or higher than the target voltage, a direct current bias current is passed through the two bias coils by the current circuit.

Then, a DC magnetic field is linked to the first magnetic core by the bias current. Then, as shown in the magnetic hysteresis curve (BH curve) of the magnetic core in FIG. 5A, a magnetomotive force is generated by the current flowing by the resonance voltage applied to the primary coil. Since the bias is applied to the plus side by the DC magnetic field generated by the current flowing through the bias coil, the first magnetic core is saturated with a smaller magnetomotive force than in the case where no bias current is passed, and one of the first magnetic cores is saturated. Then, since the bias is applied to the minus side by the DC magnetic field due to the reverse current flowing in the other bias coil, it reaches -Bm with less magnetomotive force than in the state where no bias current flows, and the other first magnetic core becomes Saturates. That is, even if the resonance voltage applied to the first magnetic core is less than the saturation voltage, one of the two first magnetic cores is saturated. When one of the first magnetic cores is saturated, the inductance of the primary coil is reduced and a current flows rapidly, and the other first magnetic core is saturated (in the case where a diode is connected to the bias coil) When one of the first magnetic cores is saturated, the balance of the electromotive force generated in the bias coil by the primary coil is lost, the electromotive force acts in the forward direction of the bias coil current, and the circulating current flows through the bias coil through the diode. Since this circulating current instantaneously saturates the other first magnetic core, the voltage value due to the imbalance of the electromotive force generated in the bias coil can be suppressed. Thus, as shown in FIG. 5 (b), the apparent BH curve narrows, and the alternating magnetic voltage (<saturation voltage) generating the magnetic field A reaches the saturation magnetic flux density and the first magnetic core is saturated. To do. Then, with an alternating voltage (<saturation voltage), a current suddenly flows through the primary coil, and the resonance voltage of the resonance circuit is suppressed to the target voltage.
Since the bias current flows when the load voltage (the voltage across the output capacitor) becomes equal to or higher than the target voltage, the resonance voltage of the resonance circuit, that is, the voltage across the output capacitor is suppressed to the target voltage.
In this way, with a simple configuration, it is possible to realize constant voltage control that can stably control the load voltage to the target voltage without considering the environmental temperature and the magnetic characteristics of the magnetic core.

According to the second aspect of the present invention, there is provided a non-contact power supply facility for supplying power to a power storage means (battery) without contact from a primary induction line or a primary power supply coil to which a high-frequency current is supplied. A secondary power receiving circuit,
A receiving coil in which an electromotive force is induced from the primary-side induction line or the primary-side feeding coil, and a resonance circuit that is connected in parallel to the receiving coil and resonates with the frequency of the receiving coil and the high-frequency current are formed. And a saturable reactor connected to both ends of the resonance circuit,
The saturable reactor includes a plurality of first magnetic cores, a primary coil wound around the plurality of first magnetic cores and connected in parallel to the resonance circuit, and the plurality of first magnetic cores. Commonly, a secondary coil wound with a smaller number of turns than the primary coil and each of the first magnetic cores are connected so that the electromotive forces cancel each other when a current flows through the primary coil. And a rectifier circuit that rectifies current output from the secondary coil of the saturable reactor and outputs the rectified current to the power storage means, and the total cross-sectional area of the first magnetic core is the first magnetic body The saturation voltage of the entire core is set to be higher than the target voltage required by the load, and when the voltage of the power storage means becomes equal to or higher than the target voltage, a DC bias current is passed through the bias coil, and the first Magnetism It is characterized in that a current circuit to saturate the core.

According to the said structure, there exist the following effects.
First, a description will be given of the operation when the first magnetic core is composed of two pieces, and the bias coil is composed of two first magnetic cores, and no bias current flows through these bias coils. When the resonance voltage of the resonance circuit is lower than the saturation voltage of the first magnetic core of the saturable reactor, the voltage is lowered from the resonance voltage by the action of the transformer of the primary coil and the secondary coil, and is output from the resonance circuit. The (constant) current is rectified by the rectifier circuit and supplied to the storage means. Further, when the voltage of the power storage means rises and the resonance voltage of the resonance circuit becomes equal to or higher than the saturation voltage of the first magnetic core, the inductance of the primary coil is reduced and a current flows rapidly to the primary coil, and the resonance voltage of the resonance circuit is The saturation voltage of the first magnetic core is suppressed, and the voltage of the secondary coil, that is, the voltage of the power storage means is suppressed to less than the saturation voltage of the first magnetic core. This is because, in the magnetic hysteresis curve (BH curve) of the magnetic core in FIG. 5A, BH is between + Bm in the first quadrant and -Bm in the third quadrant between the positive and negative cycles. It is understood as a transition state.
At this time, the two bias coils wound around the first magnetic core are connected so that the electromotive forces generated when a current flows through the primary coil cancel each other, that is, with opposite polarities. Since the electromotive forces generated in these bias coils cancel each other and balance, current does not flow through the bias coils, and therefore the primary coil is not affected.

Based on such an operation, the operation when a bias current flows through the two bias coils wound around the two first magnetic cores will be described.
Since the saturation voltage of the first magnetic core varies depending on the temperature of the environment and the magnetic characteristics of the magnetic core, the saturation voltage of the first magnetic core is set higher than the target voltage required by the storage means, A constant voltage control is performed to a target voltage that is lower than the saturation voltage of the first magnetic core, using a backup voltage that suppresses the voltage applied to the means.
That is, when the voltage of the power storage means becomes equal to or higher than the target voltage, a direct current bias current is passed through the two bias coils by the current circuit.
The action when a DC bias current is passed through the bias coil is as described above, and the voltage of the storage means is suppressed to the target voltage.
In this way, with a simple configuration, it is possible to realize constant voltage control that can stably control the voltage of the power storage means to the target voltage without considering the environmental temperature and the magnetic characteristics of the magnetic core.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the current circuit includes switch means that operates when a voltage of the load or the storage means becomes equal to or higher than the target voltage; When the switch means is operated, it comprises current means for supplying a bias current to the bias coil, and circulation means connected to both ends of the bias coil for circulating the current flowing through the bias coil. .

According to the said structure, there exist the following effects.
The operation when the first magnetic core is composed of two pieces and the bias coil wound around each of the first magnetic cores is composed of two pieces will be described.
When the voltage of the load or the storage means becomes equal to or higher than the target voltage, the switch means operates, and when the switch means operates, a bias current flows to the two bias coils by the current means. The current is supplied from an output capacitor or power storage means.
When the bias current flows through the two bias coils, out of the magnetic fluxes (electromotive forces) generated in the respective bias coils in opposite directions, the direction of the magnetic flux is opposite to the direction of the magnetic flux generated by the bias current. One of the magnetic fluxes generated in the current is canceled, and the magnetic flux generated by the bias current is added to the other magnetic flux, and an electromotive force is always generated in the direction in which the bias current flows at both ends of the two bias coils. A circulating current having a current value far exceeding the bias current flows through a closed circuit composed of two bias coils and circulating means. Since the magnetic field bias a is generated by this circulating current, the first bias current to be applied may be small enough to generate the circulating current.
As described above, the voltage of the load or the battery is suppressed to the target voltage by this bias current.
In addition, it is not necessary to replace the saturable reactor itself when changing the target voltage of the load or the power storage means, and the countermeasure can be easily performed by changing the operating voltage of the switch means.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the saturable reactor has a second magnetic property having a larger magnetic resistance than the first magnetic core. A primary core is wound around the first magnetic core, and then the primary coil is wound around the second magnetic core.

According to the said structure, there exist the following effects.
A magnetic flux is generated in the first magnetic core and the second magnetic core by the current flowing through the primary coil. In this state, the primary coil exhibits a large inductance value.
When the voltage across the primary coil (resonance voltage) increases, the first magnetic core has a lower magnetic resistance than the second magnetic core, so that the first magnetic core is saturated first and the first magnetic core is saturated. The magnetic permeability of the body core rapidly decreases to approximately 1 (μ = 1), the inductance of the primary coil wound around the first magnetic core rapidly decreases, and the pulse current starts to flow rapidly. At this time, since the second magnetic core is not yet saturated, the primary coil wound around the second magnetic core according to the magnetic permeability (decreasing) of the second magnetic core at this time The inductance is maintained at a certain value. Therefore, even if the first magnetic core is magnetically saturated, the pulse current flowing through the primary coil is not so steep and excessive. When the pulse current flows, the voltage across the primary coil (resonance voltage) is suppressed to the saturation voltage of the first magnetic core.
As described above, by providing the second magnetic core, the voltage suppressing action is gently acted, and the problems of heat generation and electromagnetic interference due to the eddy current caused by the steep and excessive pulse current can be reduced.

The invention according to claim 5 is a saturable reactor used in the secondary power receiving circuit of the non-contact power feeding facility according to any one of claims 1 to 4,
The first magnetic body core is formed by two core members having the same characteristics that form an annular magnetic path and have a cavity, and each core member is made of a low magnetic permeability material having high thermal conductivity, and the core A heat sink having a cavity with substantially the same diameter as the member is provided, and the primary coil is wound around the two core members and the heat sink using these cavities, and the one bias coil is the one core member. And the other bias coil is wound around the one core member and the heat radiating plate using a cavity of the heat radiating plate provided with the core member, and the other bias coil is provided with the other core member and the heat radiating plate provided with the core member. The one core is wound around the other core member and the heat radiating plate, and the one bias coil and the other bias coil are connected so as to have opposite polarities. .

According to the said structure, there exist the following effects.
First, heat sinks are attached with the cavities aligned for each core member, and then each bias coil is wound around each core member and its heat sink using the core member and the cavity of the heat sink.
Subsequently, the cavities of the two core members and the two heat sinks are aligned, and the primary coil is wound around the two core members and the two heat sinks using these cavities.
Subsequently, the saturable reactor is formed by connecting the bias coils so as to have the reverse polarity.
Thus, each bias coil and primary coil can be easily wound using the core member and the cavity of the heat sink, and the manufacture is facilitated.

  The secondary power receiving circuit of the contactless power supply facility according to the present invention is configured such that when the voltage of the load or the power storage means becomes equal to or higher than the target voltage required by the load or the power storage means, a DC bias current is applied to the two bias coils by the current circuit. By flowing, the voltage of the load or the storage means can be suppressed to the target voltage. Therefore, by setting the saturation voltage of the first magnetic core of the saturable reactor higher than the target voltage, Without relying on the saturation voltage of the first magnetic core that fluctuates depending on the magnetic characteristics of the magnetic core, it is possible to realize a constant voltage control to a stable target voltage. An increase in voltage of the load or power storage means can be suppressed with a saturable reactor (can be used as a backup).

It is a circuit diagram of the secondary side receiving circuit of the non-contact electric power supply equipment in Embodiment 1 of this invention. It is a perspective view of the saturable reactor used for the secondary side power receiving circuit of the non-contact electric power supply equipment. It is a characteristic view of the resonant voltage and the electric current of a primary coil in the secondary side power receiving circuit of the said non-contact electric power supply equipment. FIG. 4 is a characteristic diagram when a bias current flows in the secondary power receiving circuit of the contactless power supply facility, where (a) is a characteristic diagram of a resonance voltage and a current of a primary coil, and (b) is a characteristic diagram of the resonance voltage and the bias coil. It is a characteristic view of an electric current. It is a BH curve of a magnetic core of a saturable reactor used for the secondary receiving circuit of the same non-contact electric power supply equipment. It is a circuit diagram of the secondary side receiving circuit of the non-contact electric power supply equipment in Embodiment 2 of this invention. It is a perspective view of the saturable reactor used for the secondary side power receiving circuit of the non-contact electric power supply equipment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
FIG. 1 is a circuit diagram of a secondary-side power receiving circuit of a contactless power supply facility according to Embodiment 1 of the present invention. For example, a primary induction line or a 1-side induction line to which a high-frequency current having a constant frequency of about 10 kHz is supplied. For example, it is a secondary-side power receiving circuit of a non-contact power feeding facility that is fed contactlessly from a power feeding coil on the secondary side and feeds a load having a rated voltage of DC250V ± 5%.
As shown in FIG. 1, the secondary power receiving circuit of the contactless power supply facility is
A receiving coil 12 in which an electromotive force is induced from a primary induction line 11 (or a feeding coil) to which a high-frequency current is supplied;
A resonance capacitor 14 connected in parallel to the power reception coil 12 and forming a resonance circuit 13 that resonates with the power reception coil 12 and the frequency of the high-frequency current;
A saturable reactor 15 connected to both ends of the resonance circuit 13;
A rectifier circuit (full-wave rectifier) 16 that rectifies and outputs a current output from the resonance circuit 13;
A choke coil 17 having one end connected to the positive output terminal of the rectifier circuit 16;
An output capacitor 19 connected between the other end of the choke coil 17 and the negative output terminal of the rectifier circuit 16 and connected in parallel with the load 18 via the choke coil 17 is provided at the output end of the rectifier circuit 16. .

As shown in FIG. 2, the saturable core reactor 15 includes two magnetic cores 21 having the same characteristics without gaps as first magnetic cores 21 that form a continuous annular magnetic path with extremely low magnetic resistance. As the second magnetic core 25 having the annular first core members 22 and 23 and forming an annular magnetic path having a larger magnetic resistance than the first magnetic core 21 (first core members 22 and 23), a gap ( An annular second core member 27 with a gap (gap) 26 is provided.
The core members 22, 23, and 27 are made of a high permeability material having the same characteristics and have substantially the same cross-sectional area. However, by providing a gap 26 in the second core member 27, the second core member 27 is provided. Is set lower than the permeability of the first core members 22 and 23, and the saturation voltage of the second core member 27 is set higher than the saturation voltage of the first core members 22 and 23. The first core members 22 and 23 (first magnetic core 21) are selected to have an allowable upper limit voltage (> rated voltage) whose saturation voltage is higher than the target voltage (corresponding to the rated voltage) required by the load 18. The saturation voltage of the first magnetic core 21 is set higher than the target voltage required by the load 18.

Further, a heat radiating plate 29 made of a low magnetic permeability material having a high thermal conductivity is attached to each of the core members 22, 23 and 27. In addition, the heat sink 29 to which the second core member 27 is attached may not be a heat sink and may simply support the second core member 27. Further, these heat radiating plates 29 are arranged in parallel and are erected on the pedestal 30, and the core members 22, 23, 27 and the cavity 31 of the heat radiating plate 29 have substantially the same diameter.
Further, the primary coil 33 is wound around the two first core members 22 and 23 (and the heat radiating plate 29) using the first core members 22 and 23 and the cavity 31 of the heat radiating plate 29, followed by the primary. The coil 33 is wound around the second core member 27 (and the heat sink 29) using the cavity 31 of the second core member 27 and the heat sink 29. Further, both ends of the primary coil 33 are connected to a terminal block 34 disposed on the pedestal 30 and connected in parallel to the resonance circuit 13.
The first bias coil 36 is wound around the first core member 22 (and the heat radiating plate 29) using the first core member 22 and the cavity 31 of the heat radiating plate 29 provided with the first core member 22. ing. A second bias coil that is the same (same characteristics and length) as the first bias coil 36 by using the other first core member 23 and the cavity 31 of the heat sink 29 provided with the first core member 23. 37 is wound around the other first core member 23 (and the heat sink 29). The first bias coil 36 and the second bias coil 37 are connected in series so as to have opposite polarities, and both ends thereof are connected to a terminal block 34 disposed on the pedestal 30.
As described above, the saturable reactor 15 includes two (a plurality of examples) first core members 22 and 23 (first magnetic core 21) and the first core members 22 and 23 (first magnetic core). 21) and the primary coil 33 wound in common with the resonance circuit 13 and the first core members 22 and 23, respectively. The electromotive force cancels when the current flows through the primary coil 33. In other words, the bias coils 36 and 37 are connected in opposite polarities, and the total cross-sectional area of the first core members 22 and 23 requires that the load 18 requires the saturation voltage of the first magnetic core 21 (whole). It is set to be higher than the target voltage.
Further, the primary coil 33 and the bias coils 36 and 37 can be easily wound using the first core members 22 and 23 and the cavity 31 of the heat radiating plate 29 to facilitate manufacture.

  When the voltage across the output capacitor 19 (the voltage applied to the load 18) exceeds the target voltage required by the load 18, a DC bias current is passed through the bias coils 36 and 37 to saturate the first magnetic core 21. Current circuit 41 is provided (details will be described later).

This current circuit 41 is
A cathode connected to the positive electrode of the output capacitor 19, and a constant voltage diode (Zener diode; an example of a switch means) 42 that conducts when the voltage across the output capacitor 19 is equal to or higher than the target voltage;
A resistor (an example of current means) 43 having one end connected to the anode of the constant voltage diode 42 and the other end connected to one end of two bias coils 36 and 37 connected in series;
The cathode is connected to the connection point of the other end of the resistor 43 and one end of the two bias coils 36 and 37, and the anode is connected to the negative electrode of the output capacitor 19 and the connection point of the other end of the two bias coils 36 and 37. Connected, that is, connected to both ends of the two bias coils 36 and 37, and circulating diodes (an example of a circulating means) 44 that circulates the current flowing through the two bias coils 36 and 37.
It has.

The constant voltage diode 42 constitutes a switch means 46 which is shown as an equivalent circuit in FIG. 1 and operates when the voltage across the output capacitor 19 becomes equal to or higher than the target voltage, and the breakdown voltage (zener voltage) is the target voltage (Zener voltage). For example, 240V) is selected.
Further, the resistor 43 constitutes a current means 47 for supplying a bias current to the two bias coils 36 and 37 when the switching means 46 shown in FIG. 1 is operated, that is, when the constant voltage diode 42 is turned on. The resistance value is selected to be large when the bias current is small and conversely small when the bias current is large. Current is supplied from the output capacitor 19.
The bias current is a current that generates a circulating current, which will be described later, and saturates the first magnetic core 21. For example, 10 mA is applied.

The operation of the above configuration will be described.
First, the operation when the bias current is not passed through the two bias coils 36 and 37 will be described.
When the resonance voltage of the resonance circuit 13 applied to the primary coil 33 of the saturable reactor 15 is less than the saturation voltage of the first magnetic core 21, the (constant) current output from the resonance circuit 13 is the rectifier circuit 16. Is supplied to the load 18 and the output capacitor 19, and the output capacitor 19 is filled. In this state, the primary coil 33 exhibits a large inductance.
In the region where the first magnetic core 21 is not magnetically saturated, the first magnetic core 21 (first core members 22 and 23) of the saturable reactor 15 is the second magnetic core 25 (second core). Since the magnetic resistance is smaller than that of the member 27), the magnetic field due to the current flowing through the primary coil 33 generates a larger magnetic flux in the first magnetic core 21 than in the second magnetic core 25.

When the load 18 decreases, the voltage across the output capacitor 19 rises, the voltage across the primary coil 33 (resonance voltage) rises, and the first magnetic core 21 of the saturable reactor 15 becomes saturated (saturated). When the voltage is equal to or higher than the voltage, the first magnetic core 21 has a lower magnetic resistance than the second magnetic core 25, so that the first magnetic core 21 is saturated first and the magnetic permeability of the first magnetic core 21 is increased. It suddenly decreases to approximately 1 (μ = 1), the inductance of the primary coil 33 wound around the first magnetic core 21 decreases rapidly, and a pulse current starts to flow rapidly. At this time, since the second magnetic core 25 is not yet saturated, the second magnetic core 25 is wound around the second magnetic core 25 according to the magnetic permeability (decreasing) of the second magnetic core 25 at this time. The inductance of the primary coil 33 is maintained at a certain value. Therefore, even if the first magnetic core 21 is magnetically saturated, the pulse current flowing through the primary coil 33 is not so steep and excessive. As described above, by providing the second magnetic core 25, the function of suppressing the voltage gently works, and the problem of heat generation and electromagnetic interference due to the eddy current caused by the steep and excessive pulse current is reduced. .
When the pulse current flows, the voltage across the primary coil 33 (resonance voltage) is suppressed to the saturation voltage of the first magnetic core 21, and thus the voltage across the output capacitor 19, that is, the voltage applied to the load 18 is , The saturation voltage is suppressed below. FIG. 3 shows a characteristic diagram of the resonance voltage and the pulse current flowing through the primary coil 33. This is because, in the magnetic hysteresis curve (BH curve) of the first magnetic core 21 in FIG. 5A, B is between + Bm in the first quadrant and -Bm in the third quadrant between the positive and negative cycles. It is understood as a state where -H is transitioning.

  The two bias coils 36 and 37 are respectively wound around the first magnetic core 21 (first core members 22 and 23) of the saturable reactor 15 and current is caused to flow through the primary coil 33. Since the electromotive forces cancel each other, that is, by being connected in the opposite polarity, the electromotive forces generated in these bias coils 36 and 37 cancel each other and balance, so that current flows in the bias coils 36 and 37. There is nothing, so the primary coil 33 is not affected.

Based on the premise of the above operation, the operation when a bias current flows through the two bias coils 36 and 37 wound around the first core members 22 and 23 will be described.
Since the saturation voltage of the first magnetic core 21 varies depending on the environmental temperature and the magnetic characteristics of the magnetic core, as described above, the saturation voltage of the first magnetic core 21 is the target voltage required by the load 18. The allowable upper limit voltage (> rated voltage) of the load 18 that is higher than {the voltage across the output capacitor 19; equivalent to the rated voltage of the load 18} is set as a backup voltage that suppresses the voltage applied to the load 18. As described above, the saturable reactor 15 is used as a backup for suppressing the voltage applied to the load 18.

  When the voltage of the output capacitor 19 becomes equal to or higher than the target voltage {breakdown voltage (zener voltage)}, the constant voltage diode 42 is turned on, and the current defined by the resistance value of the resistor 43 is biased to the two bias coils 36 and 37. It flows as current. The current is supplied from the output capacitor 19. That is, as shown in FIG. 1 as an equivalent circuit, the constant voltage diode 42 serves as a switch means 46 for determining whether or not to pass a bias current, and the output capacitor 19 and the resistor 43 serve as current means 47. A bias current is supplied to the bias coils 36 and 37. As described above, the current circuit 41 supplies a DC bias current to the two bias coils 36 and 37.

  A DC magnetic field is linked to the first magnetic core 21 (first core members 22 and 23) by this bias current. Then, as shown in the magnetic hysteresis curve (BH curve) of the first magnetic core 21 in FIG. 5A, a magnetomotive force is generated by the current flowing by the resonance voltage applied to the primary coil 33. In this cycle, a bias a is applied to the plus side by a DC magnetic field generated by a current flowing through one bias coil 36 (37), so that it reaches + Bm with a small magnetomotive force compared to a state where no bias current flows, and the first core of one of them. The member 22 (23) is saturated, and in a negative cycle, the bias a is applied to the negative side due to the DC magnetic field caused by the reverse current flowing in the other bias coil 37 (36), so that it is less than the state where no bias current is passed. The magnetomotive force reaches −Bm and the other first magnetic core 23 (22) is saturated. That is, even if the resonance voltage applied to the first magnetic core 21 is less than the saturation voltage, one of the two first core members 22 or 23 is saturated. When one of the first magnetic cores 22 (23) is saturated, the inductance of the primary coil 33 is reduced, a current flows rapidly, and the other first core member 23 (22) is also saturated. In this way, as shown in FIG. 5B, the apparent BH curve is narrowed, and at the voltage (<saturation voltage) that generates the magnetic field A, the saturation magnetic flux density is reached and the first magnetic core 21 is saturated. To do.

  The bias current flows when the voltage of the output capacitor 19 becomes equal to or higher than the target voltage. Therefore, when the voltage of the output capacitor 19 becomes equal to or higher than the target voltage, a bias a is applied and the first magnetic core 21 is saturated and the resonance voltage is increased. At the target voltage (<saturation voltage), a pulse current flows through the primary coil 33, the resonance voltage of the resonance circuit 13 is suppressed to this target voltage, and the voltage applied to the load 18 is stably controlled to the target voltage. .

Further, when one of the first core members 22 (23) is saturated, the balance of electromotive forces generated in the bias coils 36 and 37 by the primary coil 33 is lost, and the electromotive force acts in the forward direction of the bias coil current, so that two biases are applied. A circulating current having a current value far exceeding the bias current flows through a closed circuit including the coils 36 and 37 and the circulating diode 44. Since the magnetic field bias a is generated by this circulating current, the first bias current to be applied may be small enough to generate the circulating current. As described above, the voltage across the output capacitor 19, that is, the voltage applied to the load 18, is controlled to the target voltage by this bias current. In addition, since the circulating current instantaneously saturates the other first core member 23 (22), the voltage value due to the imbalance of the electromotive force generated in the bias coils 36 and 37 can be suppressed.
FIG. 4A shows a characteristic diagram of the resonance voltage and the pulse current flowing through the primary coil 33 when a bias current flows, and FIG. 4B shows a characteristic diagram of the resonance voltage and the bias current.

  As described above, according to the first embodiment, the load 18 can be obtained with a simple configuration of adding the two bias coils 36 and 37 and the current circuit 41 without considering the environmental temperature and the magnetic characteristics of the magnetic core. Constant voltage control that can stably control the voltage applied to the target voltage can be realized. In the unlikely event that a malfunction occurs in the current circuit 41, the increase in the voltage of the load 18 can be suppressed by the saturable reactor 15 (can be used as a backup).

  Further, according to the first embodiment, when the target voltage is changed, it is not necessary to replace the saturable reactor 15 itself, and the breakdown voltage (zener voltage) of the constant voltage diode 42 is replaced with a voltage matching the target voltage. (The operation voltage of the switch means 46 may be changed), which can be easily dealt with.

  Further, according to the first embodiment, since the bias a can be changed by the bias current, when the resistance value of the resistor 43 is decreased and the bias current is increased, constant voltage control with quick response can be realized, and conversely the resistor 43 When the bias current is decreased by increasing the resistance value, constant voltage control with a gradual response can be realized.

[Embodiment 2]
FIG. 6 is a circuit diagram of a secondary-side power receiving circuit of the contactless power supply facility according to Embodiment 2 of the present invention. For example, the primary-side induction line or the 1-side induction line to which a high-frequency current having a constant frequency of about 10 kHz is supplied. It is the secondary side power receiving circuit of the non-contact electric power feeding equipment which is fed non-contact from the secondary side feeding coil and feeds the battery. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

In the second embodiment, the load 18 is a battery (an example of a power storage unit) 51, is separated from the saturable reactor 15 and the rectifier circuit 16, and the first magnetic core 21 of the saturable reactor 15 has a smaller number of turns than the primary 33. The saturable reactor 15 ′ is formed by winding the secondary coil 52, the rectifier circuit 16 is connected to both ends of the secondary secondary coil 52 of the saturable reactor 15 ′, and the current output from the secondary coil 52 is rectified. And output to the battery 51.
As shown in FIG. 7, the secondary coil 52 is formed into two first core members 22, 23 using the first core members 22, 23 (first magnetic core 21) and the cavity 31 of the heat sink 29. Commonly wound and both ends thereof are connected to a terminal block 34 disposed on the pedestal 30.

The first magnetic core 21 of the saturable reactor 15 ′ is selected so that the saturation voltage is set to an allowable upper limit voltage higher than the target voltage (corresponding to the charging voltage) required by the battery 51. The saturation voltage of the first magnetic core 21 is set higher than the target voltage required by the battery 51.
The constant voltage diode 42 is selected so that the breakdown voltage (zener voltage) is the target voltage (corresponding to the charging voltage) required by the battery 51.

According to such a configuration, the high resonance voltage can be stepped down to the rated voltage of the low voltage battery 51 according to the winding ratio by the action of the transformer of the primary coil 33 and the secondary coil 52, and the rating of the battery 51 can be reduced. Constant voltage control to a voltage (for example, 12V) can be realized.
The operation of stably controlling the voltage applied to the battery 51 to the target voltage by the configuration of the two bias coils 36 and 37 and the current circuit 41 is the same as the operation of the first embodiment, and the description thereof is omitted. To do.

  As described above, according to the second embodiment, the temperature of the environment and the magnetic characteristics of the magnetic core are taken into account with a simple configuration in which the two bias coils 36 and 37, the secondary coil 52, and the current circuit 41 are added. Therefore, it is possible to realize constant voltage control capable of stably controlling the voltage applied to the battery 51 to the target voltage. In the unlikely event that a malfunction occurs in the current circuit 41, the increase in the voltage of the battery 51 can be suppressed by the saturable reactor 15 '(can be used as a backup).

In the first or second embodiment, the saturable reactors 15 and 15 ′ are provided with the second magnetic core 25 and wound around a part of the primary coil 33, but the second magnetic core 25 is not necessarily provided. Even if it is not necessary, the saturable reactors 15 and 15 ′ can function to suppress the resonance voltage.
In the first or second embodiment, the first magnetic core 21 is composed of the two first core members 22 and 23, but may be composed of a larger number of core members. The primary coil 33 is wound around these core members in common. The bias coils are wound around the first core members and connected in series. When they are connected, the electromotive forces are connected so as to cancel each other when a current flows through the primary coil 33. The secondary coil 52 is wound around these core members in common. In the first or second embodiment, the resistor 43 is used as an element for defining the bias current, but a constant current diode may be used. At this time, the constant current diode has an anode connected to the anode of the constant voltage diode 42 and a cathode connected to one end of the two bias coils 36 and 37.
In Embodiment 1 or 2, the battery 51 is charged as the power storage means, but the power storage means may be an electric double layer capacitor.

DESCRIPTION OF SYMBOLS 11 Induction line 12 Power receiving coil 13 Resonant circuit 14 Resonant capacitor 15, 15 'Saturable reactor 16 Rectifier circuit 17 Choke coil 18 Load 19 Output capacitor 21 1st magnetic core 22, 22 1st core member (no gap)
25 Second magnetic core 26 Gap 27 Second core member (with gap)
DESCRIPTION OF SYMBOLS 29 Heat sink 31 Cavity 33 Primary coil 36 1st bias coil 37 2nd bias coil 41 Current circuit 42 Constant voltage diode 43 Resistance 44 Circulation diode 46 Switch means 47 Current means 51 Battery 52 Secondary coil

Claims (5)

A secondary side power receiving circuit of a non-contact power feeding facility that is fed contactlessly from a primary side induction line or a primary side feeding coil to which a high-frequency current is supplied and feeds a load,
A receiving coil in which an electromotive force is induced from the primary side induction line or the primary side feeding coil;
A resonant capacitor connected in parallel to the power receiving coil and forming a resonant circuit that resonates with the power receiving coil and the frequency of the high frequency current;
A saturable reactor connected to both ends of the resonant circuit;
A rectifier circuit that rectifies and outputs a current output from the resonant circuit;
An output capacitor connected in parallel with the load at the output end of the rectifier circuit,
The saturable reactor is
A plurality of first magnetic cores;
A primary coil wound around the plurality of first magnetic cores and connected in parallel to the resonant circuit;
A bias coil wound around each of the first magnetic cores and connected so that electromotive forces cancel each other when a current flows through the primary coil;
The total cross-sectional area of the first magnetic core is set so that the saturation voltage of the entire first magnetic core is higher than the target voltage required by the load,
A secondary side of a contactless power supply facility, comprising: a current circuit that causes a DC bias current to flow through the bias coil and saturate the first magnetic core when the load voltage is equal to or higher than the target voltage. Power receiving circuit. A secondary-side power receiving circuit of a non-contact power feeding facility that is fed contactlessly from a primary induction line or a primary feeding coil to which a high-frequency current is supplied and feeds power storage means,
A receiving coil in which an electromotive force is induced from the primary side induction line or the primary side feeding coil;
A resonant capacitor connected in parallel to the power receiving coil and forming a resonant circuit that resonates with the power receiving coil and the frequency of the high frequency current;
Comprising a saturable reactor connected to both ends of the resonant circuit;
The saturable reactor is
A plurality of first magnetic cores;
A primary coil wound around the plurality of first magnetic cores and connected in parallel to the resonant circuit;
A secondary coil wound with a smaller number of turns than the primary coil in common to the plurality of first magnetic cores;
A bias coil wound around each of the first magnetic cores and connected so that electromotive forces cancel each other when a current flows through the primary coil;
A rectifier circuit that rectifies the current output from the secondary coil of the saturable reactor and outputs the rectified current to the power storage means;
The total cross-sectional area of the first magnetic core is set so that the saturation voltage of the entire first magnetic core is higher than the target voltage required by the load,
2. A non-contact power supply facility comprising: a current circuit for supplying a DC bias current to the bias coil and saturating the first magnetic core when the voltage of the power storage unit becomes equal to or higher than the target voltage. Secondary power receiving circuit. The current circuit is
Switch means that operates when the voltage of the load or power storage means is equal to or higher than the target voltage;
When the switch-on means operates, current means for supplying a bias current to the bias coil;
The secondary-side power receiving circuit of the non-contact power feeding equipment according to claim 1, further comprising a circulation unit that is connected to both ends of the bias coil and circulates a current flowing through the bias coil. The saturable reactor includes a second magnetic core having a magnetic resistance larger than that of the first magnetic core, and the primary coil is wound around the first magnetic core, and then the primary coil is wound on the second magnetic core. The secondary side power reception circuit of the non-contact electric power supply equipment according to any one of claims 1 to 3, wherein It is a saturable reactor used for the secondary receiving circuit of the non-contact electric power supply equipment according to any one of claims 1 to 4,
The first magnetic core is formed by two core members having the same characteristics, forming an annular magnetic path and having a cavity,
Each of the core members is made of a low magnetic permeability material having a high thermal conductivity, and is provided with a heat sink having a cavity having substantially the same diameter as the core member,
The primary coil is wound around the two core members and the heat sink using these cavities,
The one bias coil is wound around the one core member and the heat radiating plate using the one core member and a cavity of the heat radiating plate provided with the core member,
The other bias coil is wound around the other core member and the heat sink using the other core member and a cavity of the heat sink provided with the core member,
The saturable reactor is characterized in that the one bias coil and the other bias coil are connected to have opposite polarities.

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