JP7518510B2 - Power Supply System - Google Patents

Description

The present invention relates to a power supply system.

The contactless electric field coupling power supply technology is an excellent power supply technology that can transmit power via the junction capacitance between non-contact electrodes (see, for example, Patent Document 1). However, since the junction capacitance is small due to the non-contact nature of the technology, it is necessary to increase the junction capacitance by increasing the voltage or frequency.
However, if the voltage or frequency is increased without reason, the electromagnetic field radiated from the junction capacitance to the outside will become larger, which is undesirable. For this reason, the electric field coupling non-contact power supply technology uses the ISM band, which includes 6.78 MHz, a globally recognized frequency where external electromagnetic field radiation is relatively permitted. The "ISM band" refers to a license-free frequency band that is internationally reserved for the use of radio frequency (RF) energy for industrial, scientific, and medical purposes other than telecommunications.

Patent No. 6586460

In order to meet the demand for rapid charging that has accompanied the recent development of batteries and capacitors, it is necessary to transmit large amounts of power in a short time. To achieve this with electric field coupling non-contact power supply technology, it is necessary to increase the voltage and frequency even more than before. In this case, further electromagnetic radiation will occur. As the snake limit in the relationship between frequency and magnetic permeability shows, increasing the frequency reduces the magnetic permeability of magnetic materials and increases losses. For this reason, the core material heats up during high power transmission, causing the resonant circuit to become out of tune. As a result, it is expected that it will become difficult to apply electric field coupling non-contact power supply technology to high power transmission.

The present invention was made in consideration of these circumstances, and aims to provide a method for realizing high-power rapid charging of rapid-chargeable batteries and capacitors, and transmission of power to large loads such as robots.

The power supply system of the present invention comprises:
A power supply system including a power transmitting side having a power transmitting electrode that transmits power from a power source, and a power receiving side having a power receiving electrode that receives the power transmitted from the power transmitting electrode via a junction capacitance,
The power receiving side is
a first layer made of an insulating elastic material, a second layer made of a flexible thin-plate-shaped conductor, and a conductive elastic material connecting an end of the second layer to the power receiving electrode, on a surface of the power receiving electrode facing the power transmitting electrode;
an insulating film is disposed on a surface of the second layer facing the power transmitting electrode;
When the second layer is in contact with or in close proximity to the power transmitting electrode, power from the power transmitting electrode is received by the power receiving electrode via the second layer and the conductive elastic body.

The present invention makes it possible to realize high-power rapid charging of rapid-chargeable batteries and capacitors, as well as power transmission to large loads such as robots.

FIG. 1 is a circuit diagram showing an overview of a contactless power supply circuit of an electric field coupling type as a conventional technique. 1A to 1C are diagrams illustrating examples of contact power supply when the power transmitting electrode and the power receiving electrode are both made of rigid metal and when a thin metal plate backed with an elastic body is used. FIG. 3 is a diagram showing the results of an experiment for three different cases conducted to verify the contents of FIG. 2 . FIG. 4 is a diagram showing a specific example of an electrode structure designed based on the experimental results of FIG. 3. FIG. 5 is a diagram showing that the electrode structure of FIG. 4 can accommodate relatively large waviness. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a flyback transformer. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a forward inverter. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a full bridge circuit. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a full bridge circuit and a resonant circuit. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a push-pull circuit. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a half-bridge circuit. FIG. 1 is a diagram showing a specific example of a contactless power supply circuit of an electric field coupling type using a half-bridge circuit and a resonant circuit. FIG. 1 is a diagram illustrating an example of communication control in a contactless power supply circuit using an electric field coupling method.

One embodiment of the power supply system of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiment.

First, referring to FIG. 1, the problems with a conventional contactless power supply circuit of the electric field coupling type will be described in detail.
FIG. 1 is a circuit diagram showing an outline of a conventional contactless power supply circuit of an electric field coupling type.

The conventional contactless power supply circuit of the electric field coupling type needs to operate at a high frequency of 6.78 MHz from the viewpoint of practicality and the amount of electromagnetic field radiated to the outside.
However, the magnetic permeability (μ') of the magnetic material used as the inductance of the circuit can only be small because there is a limit to the frequency at which magnetism is expressed (the so-called snake limit), and this causes the problem of increased loss (μ''). This means that there is a limit to how much magnetic flux can be confined within the core and that the core will heat up. There is also the problem that the coil wire itself generates heat due to the skin effect and proximity effect.
Under such circumstances, even if a high-power inverter is developed, the coil L will generate heat. Even if the resonance frequency is adjusted using the coil L and the capacitor C, the impedance will change due to heat generation, causing the resonance to shift.

The circuit diagram of FIG. 1 includes three resonant circuits.
The first resonant circuit is a circuit that constitutes a part of the oscillator circuit, and resonates with the coil L1 and the capacitor C1. The first resonant circuit converts a square wave generated by the FET (field effect transistor) full bridge circuit of the inverter into a sine wave by resonance. The first resonant circuit also aims to reduce loss by controlling the relationship between the voltage applied to the FET of the full bridge circuit and the current flowing therethrough. This control is realized, for example, by ZVS (zero volt switching) performed when the voltage is zero, or ZCS (zero current switching) performed when the current is zero.

The second resonant circuit is a circuit that constitutes part of the junction capacitance/parallel resonant circuit, and resonates with the secondary inductance of transformer T2 and capacitor C2. In order to increase the current flowing through the junction capacitance, it is necessary to increase the voltage, and transformer T2 boosts the voltage to increase it. This makes it possible to boost the voltage of the second resonant circuit by Q times (Q is an integer value greater than 1).

The third resonant circuit is a circuit that constitutes a part of the junction capacitance-parallel resonant circuit, and resonates with the primary inductance of the transformer T3 and the capacitor C3. The third resonant circuit exists as a parallel resonant circuit behind the junction capacitances _CA and _CB , and therefore has a high impedance during resonance. Therefore, if the impedance of the third resonant circuit is higher than the combined impedance of the junction capacitances _CA and _CB , efficient power transmission is possible. Furthermore, the transformer T3 also plays a role in stepping down the boosted voltage.

When the junction capacitances C _A and C _B become large, the second and third resonant circuits become unnecessary together with the transformers T ₂ and T _3. Products having resonant circuits require adjustment of the resonant circuits before shipping. Furthermore, if the tuning is detuned after shipping, it will cause a decrease in performance. Therefore, in products having resonant circuits, the very existence of the resonant circuits is a cost factor.

As described above, the conventional contactless power supply circuit of the electric field coupling type has various problems. In contrast, the power supply system according to one embodiment of the present invention can solve the above-mentioned problems.
That is, the power supply system according to one embodiment of the present invention is an electrode-coupling type power supply system, and is a system that realizes a large amount of power supply in a short time when a mobile body on the power receiving side is stopped.

According to the power supply system according to an embodiment of the present invention, when the mobile body on the power receiving side is stopped, the electrode on the power transmitting side (hereinafter referred to as the "power transmitting electrode") and the electrode on the power receiving side (hereinafter referred to as the "power receiving electrode") are brought into close contact with each other. This allows a large junction capacitance to be formed by the coupling between the power transmitting electrode and the power receiving electrode, making it possible to supply a large amount of power in a short period of time.
As a result, it is no longer necessary to supply power to the moving body while it is moving along the transport path, and so no electromagnetic field is emitted from the transport path when power is being supplied. Although an electromagnetic field is emitted from the power supply location, the amount of electromagnetic field radiation can be efficiently reduced by simply providing a shield only at the power supply location.

In addition, since the power transmitting electrode and the power receiving electrode only need to be in close contact with each other while power is being fed, by making at least one of the power transmitting electrode and the power receiving electrode movable, the power transmitting electrode and the power receiving electrode can be in close contact with each other only while power is being fed. Specifically, for example, when a moving body acting as the power receiving side arrives at a power feeding location, the power receiving electrode may be lowered to come into close contact with the power transmitting electrode, and after power feeding is completed and before the moving body starts to move, the power receiving electrode may be raised to move away from the power transmitting electrode. This makes it possible to avoid friction between the power transmitting electrode and the power receiving electrode, thereby preventing wear of the electrodes.
In this way, by using the electrode coupling type contact power supply instead of the electric field coupling type non-contact power supply, the inverter circuit and the power transmission circuit can be simplified. Below, we will explain the large junction capacitance created by the close contact between the power transmission electrode and the power receiving electrode, and the inverter circuit.

Figure 2 shows examples of contact power transfer when both the power transmitting electrode and the power receiving electrode are made of rigid metal, and when a thin metal plate backed by an elastic material is used.

Figure 2 (A) shows the state in which an unprocessed power receiving electrode 12 is pressed against a power transmitting electrode 11. In this case, the apparent area of the surface where the power transmitting electrode 11 and the power receiving electrode 12 contact each other is large, but the total area of the points where actual contact occurs (hereinafter referred to as the "contact area") is small. Therefore, the value indicating the resistance when the power transmitting electrode 11 and the power receiving electrode 12 contact each other (hereinafter referred to as the "contact resistance value") is not reduced.

Figure 2 (B) shows the state in which the power receiving electrode 12, whose contact surface has been processed, is placed on the power transmitting electrode 11. Specifically, rubber 121 is attached to the contact surface of the power receiving electrode 12. A thin plate electrode 123 is attached to the surface of the rubber 121 via an elastic adhesive layer 122. A spring-shaped conductor 124 is connected to the end of the thin plate electrode 123. The end of the spring-shaped conductor 124 penetrates the rubber 121 and is joined to the power receiving electrode 12. However, as shown in Figure 2 (B), simply placing the power receiving electrode 12 on the power transmitting electrode 11 does not increase the contact area.

Figure 2 (C) shows the state when the power receiving electrode 12 in Figure 2 (B) is pressed against the power transmitting electrode 11. As shown in Figure 2 (C), when a pressing force P is applied, the rubber 121 and the thin plate electrode 123 deform and become accustomed to the uneven shape of the surface of the power transmitting electrode 11, which has an opposing contact surface. This makes it possible to increase the contact area. As a result, it is possible to realize a reduction in the contact resistance value.

Figure 3 shows the experimental results for three different cases conducted to verify the contents of Figure 2.

Of the three types of cases (Example Cases A to C) that were the subject of the experiment, in Example Case A, a cubic rigid electrode was placed directly on top of a rigid electrode plate and a predetermined pressing force P was applied. Specifically, a 1 cm cubic copper electrode was placed on a 2 mm thick SUS (stainless steel) plate and a load of 1.43 kg was applied. As a result, the contact resistance value of Example Case A was 200 to 600 mΩ.

In Example Case B, a cubic rigid electrode was placed on top of the rigid electrode plate, with a thin plate electrode and rubber between them, and a predetermined pressing force P was applied. Specifically, a 1 cm cubic copper electrode was placed on top of a 2 mm thick SUS (stainless steel) plate, with a 0.3 mm thick copper plate and 2.5 mm thick (1 cm square) rubber between them, and a load of 1.43 kg was applied. As a result, the contact resistance value of Example Case B was approximately 180 mΩ.

In Example C, the experiment was basically the same as in Example B, but the thickness of the copper plate was made thinner (0.1 mm). As a result, the contact resistance value of Example C was around 10 mΩ. In other words, the contact resistance value of Example C was lower than the contact resistance value of Example B.

In this way, the experiment in Figure 3 verified the results in Figure 2. Note that in implementation cases B and C, 1 cm square pieces of rubber were used. For this reason, for example, if the electrodes are arranged with 10 electrodes vertically and 10 electrodes horizontally, the contact resistance value will be 0.1 mΩ. In other words, even if a current of 100 A is passed, the power consumed by the electrodes will be just 1 W.

Figure 4 shows a specific example of an electrode structure designed based on the experimental results in Figure 3.

The experimental results shown in Figure 3 show that the precision of the contact between the electrodes can be improved by applying processing such as in Example Case B or Example Case C to the power receiving electrode. Therefore, by applying this principle to contact power supply using the electrode coupling method, the junction capacitance can be increased.

Figures 4A and 4B show an electrode structure based on Example Case C of the three examples shown in Figure 3. Hereinafter, this type of electrode structure will be referred to as an "electrode structure in which rubber-backed thin plate electrodes are arranged."
As shown in Fig. 4A, the power receiving electrode 12, which is a rigid metal, has an electrode structure in which it is in close contact with the power transmitting electrode 11 (not shown) via rubber 121, an elastic adhesive layer 122, a thin plate electrode 123, and an insulating film 125. In the example of Fig. 4, the thin plate electrode 123 and the spring-like conductor 124 are not formed as two different members as in the example of Fig. 2, but are formed as one integrally molded member (thin plate electrode 123).

The thin plate electrode 123 is fixed to the power receiving electrode 12 by rubber 121 and elastic adhesive layer 122, and the pressing force P is transmitted via the rubber 121 and elastic adhesive layer 122. The thin plate electrode 123 expands and contracts, and is fixed to the power receiving electrode 12 via a side that is expanded over the entire edge to reduce resistance, thereby reducing the contact resistance of the entire electrode. The thin plate electrode 123 is thin and has high resistance in the surface direction, so its length is set to about 10 mm.

The insulating film 125 is a thin, strong insulating film that is firmly coated on the surface of the thin plate electrode 123 (the surface facing the power transmitting electrode 11). Note that in FIG. 4, the insulating film 125 is disposed only on the surface, but it may be coated on other parts as long as electrical contact with the power receiving electrode 12 is ensured.

The insulating material that constitutes the insulating film 125 can be, for example, a DLC (diamond-like carbon) film. The DLC film is strong enough that it will not peel off even when coated on the surfaces of both the piston and cylinder of an engine. For this reason, it can be used without problems in applications where gentle contact and separation are repeated, as in this embodiment.

The material that constitutes the thin plate electrode 123 is, for example, phosphor bronze, which has been subjected to an interface treatment to increase the adhesion strength of the DLC film (insulating film 125). In this case, even if the thin plate electrode 123 is deformed, the DLC film (insulating film 125) can remain firmly attached. When the thin plate electrode 123 is deformed, the DLC film (insulating film 125) also deforms accordingly. The DLC film (insulating film 125) itself has a relative dielectric constant of about 5, a breakdown voltage of about 5 MV/cm, and a thickness of about 2 μm when formed. For this reason, it can be used as an optimal material to obtain a large coupling capacitance.

Figure 5 shows that the electrode structure in Figure 4 can accommodate relatively large swells.

The "electrode structure in which rubber-backed thin plate electrodes are arranged" can be easily adapted to the surfaces of the opposing electrodes (i.e., the power transmitting electrode 11 and the power receiving electrode 12) even when fine irregularities are formed on the surfaces, as shown in Fig. 2. Also, as shown in Fig. 5, the electrode structure can be easily adapted to the surfaces of the opposing electrodes even when relatively large undulations are formed on the surfaces of the opposing electrodes, and a large junction capacitance can be maintained. Although not shown, even when dust or the like is present on the surfaces of the opposing electrodes, the electrode structure can be made to adapt to the irregularities including the dust or the like by applying a pressing force P. Furthermore, even when the surfaces of the opposing electrodes are oxidized, the junction capacitance is slightly reduced, but still a large junction capacitance can be obtained.
In the example of FIG. 5, the end of the thin plate electrode 123 is fixed to the power receiving electrode 12 with solder H.

There is no particular limitation on how to obtain the pressing force P required when pressing the power receiving electrode 12 against the power transmitting electrode 11. For example, the pressing force P can be obtained by the following method.
That is, these include (1) a method that utilizes the weight of the receiving electrode 12 itself, (2) a method that utilizes mechanical force (for example, by applying pressure using air or oil), (3) a method that utilizes magnetic force (for example, by making the receiving electrode 12 a ferromagnetic material), and (4) a method that utilizes suction force (for example, by attracting air present in the space between the electrodes).

Next, the inverter circuit will be described with reference to FIGS.
FIG. 6 is a diagram showing a specific example of a contactless power supply circuit of the electric field coupling type using a flyback transformer.

Fig. 6A shows a circuit that uses a flyback transformer and a FET (field effect transistor) to oscillate a square wave and rectify and smooth it via junction capacitances C _A and C _B. This circuit uses a large junction capacitance to separate the junction capacitances C _A and C _B and allow them to be moved arbitrarily, as shown in Fig. 6B.

In a state where the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 6A), there is no external radiation because the degree of contact between the junction capacitances C _A and C _B is high and large. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.
By using a contactless power supply circuit of the electric field coupling type using a flyback transformer as shown in FIG. 6, it becomes possible to perform switching at any frequency and waveform.

Figure 7 shows a specific example of a contactless power supply circuit using a capacitive coupling method that uses a forward inverter.

Fig. 7A shows a circuit in which a square wave is oscillated using a forward inverter and rectified and smoothed via junction capacitances C _A and C _B. This circuit also uses large junction capacitances, allowing the junction capacitances C _A and C _B to be separated and moved arbitrarily, as shown in Fig. 7B.

In a state where the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 7A), there is no external radiation because the degree of contact between the junction capacitances C _A and C _B is high and large. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.
By using a contactless power supply circuit of the capacitive coupling type using a forward inverter as shown in FIG. 7, it becomes possible to perform switching at any frequency and waveform.

Figure 8 shows a specific example of a contactless power supply circuit using a full-bridge circuit and an electric field coupling method.

Fig. 8A shows a circuit in which a pseudo-square wave is oscillated by a full bridge circuit of FETs (field effect transistors) and rectified and smoothed via junction capacitances C _A and C _B. This circuit also uses large junction capacitances, allowing the junction capacitances C _A and C _B to be separated and moved arbitrarily, as shown in Fig. 8B.

In a state in which the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 8A), the degree of contact between the junction capacitances C _A and C _B is high and large, so there is no external radiation. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.

By using a full-bridge circuit as shown in FIG. 8 as a contactless power supply circuit of an electric field coupling type, it becomes possible to perform switching at any frequency and waveform.
Although a bridge rectifier circuit is used in the circuit shown in Fig. 8, the power receiving electrode 12a may be connected to the power transmitting electrode 11a and the power receiving electrode 12b may be connected to the power transmitting electrode 11b, or the power receiving electrode 12a may be connected to the power transmitting electrode 11b and the power receiving electrode 12b may be connected to the power transmitting electrode 11a. In addition, the circuit can be used in both the flyback inverter system shown in Fig. 6 and the forward inverter system shown in Fig. 7.
Although not shown, when three-phase power transmission is used, a three-stage full bridge is used, so that three sets of junction capacitances C _A to C _C are used. For a multi-phase power transmission, the number of junction capacitances can be increased in the same manner. In this case, the number of stages of diodes D on the power receiving electrode 12 side is increased according to the number of phases.

Figure 9 shows a specific example of a contactless power supply circuit using an electric field coupling method that uses a full bridge circuit and a resonant circuit.

FIG. 9A shows a circuit in which a sine wave is oscillated by a full bridge circuit of FETs (field effect transistors) and a resonant circuit, and rectified and smoothed through junction capacitances C A and C _B. In this circuit, too, the junction capacitances C _A and C _B can be separated and moved arbitrarily by the large junction capacitances, as shown in FIG. _9B . Furthermore, the provision of the resonant circuit enables ZVS (zero volt switching) or ZCS (zero current switching) of the FETs (field effect transistors). This can increase the transmission efficiency and reduce heat generation of the FETs (field effect transistors).

In a state where the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 9A), the degree of contact between the junction capacitances C _A and C _B is high and large, so there is no external radiation. In order to completely eliminate external radiation, a shield can be provided or an overhang structure can be adopted. In addition, radiation from the power transmitting side and the power receiving side must also be reduced.

By using a full bridge circuit and a resonant circuit as shown in FIG. 9 as a contactless power supply circuit of the electric field coupling type, it becomes possible to perform switching at any frequency and waveform. Although the resonant circuit is tuned, detuning occurs mainly due to heat generation of the inductance during high power transmission. Therefore, a gate drive circuit with an automatic tuning function is used. This maintains ZVS (zero volt switching) or ZCS (zero current switching) and enables efficient oscillation. Even if the frequency shifts due to detuning, there is no problem because there is no external radiation since closely contacted electrodes are used.
In the circuit shown in Fig. 9, similarly to the circuit shown in Fig. 8 described above, the power receiving electrode 12a may be connected to the power transmitting electrode 11a and the power receiving electrode 12b may be connected to the power transmitting electrode 11b, or the power receiving electrode 12a may be connected to the power transmitting electrode 11b and the power receiving electrode 12b may be connected to the power transmitting electrode 11a. When three-phase power transmission is used, a three-stage full bridge is used to use three sets of junction capacitances C _A to C _C , and more than one phase can be similarly increased. In this case, the number of stages of diodes D is increased on the power receiving electrode 12 side according to the number of phases.

Figure 10 shows a specific example of a contactless power supply circuit using an electric field coupling method that uses a push-pull circuit.

Fig. 10A shows a circuit in which a pseudo square wave is oscillated by a push-pull circuit of FETs (field effect transistors) and rectified and smoothed via junction capacitances C _{A and C B. This circuit also uses large junction capacitances, allowing the junction capacitances C A and C B} to be separated and moved arbitrarily, as shown in Fig. 10B.

In a state in which the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 10A), the degree of contact between the junction capacitances C _A and C _B is high and large, so there is no external radiation. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.
By using a push-pull circuit as shown in FIG. 10 as a contactless power supply circuit of an electric field coupling type, it becomes possible to perform switching at any frequency and waveform.
The circuit shown in FIG. 10 uses a bridge rectifier circuit, but the power receiving electrode 12a may be connected to the power transmitting electrode 11a and the power receiving electrode 12b may be connected to the power transmitting electrode 11b, or the power receiving electrode 12a may be connected to the power transmitting electrode 11b and the power receiving electrode 12b may be connected to the power transmitting electrode 11a.

Figure 11 shows a specific example of a contactless power supply circuit using an electric field coupling method that uses a half-bridge circuit.

Fig. 11A shows a circuit in which a pseudo square wave is oscillated by a half-bridge circuit of FETs (field effect transistors) and rectified and smoothed via junction capacitances C _{A and C B. This circuit also uses large junction capacitances, allowing the junction capacitances C A and C B} to be separated and moved arbitrarily, as shown in Fig. 11B.

In a state in which the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via a junction capacitance C _A , and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via a junction capacitance C _B (for example, the state shown in FIG. 10A), the degree of contact between the junction capacitances C _A and C _B is high and large, so there is no external radiation. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.
By using an electric field coupling type contactless power supply circuit that uses a half-bridge circuit of FETs (field effect transistors) as shown in FIG. 11, it becomes possible to perform switching at any frequency and waveform.
Although a bridge rectifier circuit is used in the circuit shown in Fig. 11, the power receiving electrode 12a may be connected to the power transmitting electrode 11a and the power receiving electrode 12b may be connected to the power transmitting electrode 11b, or the power receiving electrode 12a may be connected to the power transmitting electrode 11b and the power receiving electrode 12b may be connected to the power transmitting electrode 11a. In addition, the circuit can be used in both the flyback inverter system of Fig. 6 and the forward inverter system of Fig. 7.

Figure 12 shows a specific example of a contactless power supply circuit using an electric field coupling method that uses a half-bridge circuit and a resonant circuit.

Fig. 12A shows a circuit in which a sine wave is oscillated by a half-bridge circuit of FETs (field effect transistors) and a resonant circuit, and rectified and smoothed through junction capacitances C _{A and C B. This circuit also has a large junction capacitance, so that the junction capacitances C A and C B} can be separated and moved arbitrarily, as shown in Fig. 12B. Furthermore, the provision of a resonant circuit enables ZVS (zero volt switching) or ZCS (zero current switching) of the FETs (field effect transistors). This can increase the transmission efficiency and reduce heat generation of the FETs (field effect transistors).

In a state where the power transmitting electrode 11a and the power receiving electrode 12a are combined with each other via the junction capacitance C _A and the power transmitting electrode 11b and the power receiving electrode 12b are combined with each other via the junction capacitance C _B (for example, the state shown in FIG. 12A), the degree of contact between the junction capacitances C _A and C _B is high and large, so there is no external radiation. Although not shown, a shield can be provided or an overhang structure can be adopted to completely eliminate external radiation.
By using an electric field coupling type non-contact power supply circuit with a half bridge circuit and a resonant circuit as shown in FIG. 12, it becomes possible to perform switching at any frequency and waveform. Although the resonant circuit is tuned, detuning occurs mainly due to heat generation of the inductance during high power transmission. Therefore, a gate drive circuit with an automatic tuning function is used. This maintains ZVS (zero volt switching) or ZCS (zero current switching) and enables efficient oscillation. Even if the frequency shifts due to detuning, there is no problem because there is no external radiation since closely contacted electrodes are used.

Next, communication control in the contactless power supply circuit of the electric field coupling type will be described with reference to FIG.
FIG. 13 is a diagram showing an image of communication control in a contactless power supply circuit of the electric field coupling type.

Figure 13 shows an image of the communication control associated with the separable power transmission system described with reference to Figures 6 to 12.

As shown in Fig. 13, a control circuit is provided outside the oscillator circuit and the rectifier/smoothing circuit, respectively, to realize two-way communication. Specifically, on the transmitting side, a power transmitting side control circuit 111 controls the oscillation and stopping of the oscillator circuit, and on the receiving side, a power receiving side control circuit 126 monitors the power receiving state (output monitoring) and various conditions on the load side.
Specifically, for example, when the battery is being charged, it notifies the user that the battery is fully charged and stops oscillation on the transmitting side.
There are no particular limitations on the communication method used between the oscillator circuit and the rectifying and smoothing circuit, and the following communication method, for example, can be used.

That is, (1) a communication method in which a high-frequency signal is superimposed on the power transmission electrode 11 can be adopted. Here, "high frequency" refers to a frequency sufficiently higher than the power transmission frequency. In this case, if MHz is used for power transmission, GHz is used for communication. (2) A communication method using the power transmission frequency can be adopted. In this case, the waveform is modulated and transmitted from the transmitting side to the receiving side. Then, from the receiving side to the transmitting side, the load is changed to inform the transmitting side of the change in the current value. (3) Optical communication can be adopted. In this case, for example, an LED (light-emitting diode) or the like can be used. (4) Magnetic communication can be adopted. In this case, magnetic communication is performed by arranging coils (not shown) on both the transmitting side and the receiving side. (5) Acoustic communication can be adopted. In this case, communication is performed by transmitting ultrasonic waves through the opposing electrodes. In addition, the junction capacitance C _A side and the junction capacitance C _B side are used depending on the communication direction. As a result, even with one electrode, the communication direction can be switched using frequency division and time division.

In summary, according to this embodiment, the following effects can be expected.
In other words, in the contactless power supply using the electric field coupling method, by bringing the power transmitting electrode 11 and the power receiving electrode 12, which face each other with the insulating film 125 in between, close to each other, a large junction capacitance can be obtained, and by providing a simple shield for the power transmitting electrode 11 and the power receiving electrode 12 or by using an overhang structure, electromagnetic wave radiation can be reduced.

Under such conditions, the following two approaches can be adopted.
The first method is a method that does not use a resonant circuit. In this method, there is no need to send a sine wave, and power can be transmitted without boosting the voltage. This enables power transmission without using a resonant circuit. In addition, it is possible to significantly reduce the time costs, such as the effort required for tuning. Furthermore, there is no need to worry about tuning deviations caused by losses in the coil L. As a result, it becomes possible to supply large power. In addition, since a resonant circuit is not used, it is possible to reduce the circuit size. As a result, it is possible to reduce the cost required for production.
The second method is to drive the gate of the switching transistor using an automatic tuning function. That is, even if there is detuning of the resonant circuit due to heat generation of the inductance during high power transmission to the full-bridge circuit or half-bridge circuit, the gate of the switching transistor is driven using the automatic tuning function. This allows ZVS (zero volt switching) or ZCS (zero current switching) to function and maintain improved oscillation efficiency.
That is, according to this embodiment, it is possible to construct a power supply system that can easily transmit power by electric field coupling to a device equipped with a quick-charge battery or a lithium-ion capacitor, which have seen remarkable development in recent years.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and modifications and improvements that can achieve the object of the present invention are included in the present invention.

In summary, the power supply system to which the present invention is applied is sufficient if it has the following configuration, and can take a variety of different embodiments.
That is, the power supply system to which the present invention is applied is
A power supply system including a power transmitting side having a power transmitting electrode (e.g., the above-mentioned power transmitting electrode 11) that transmits power from a power source, and a power receiving side having a power receiving electrode (e.g., the above-mentioned power receiving electrode 12) that receives the power transmitted from the power transmitting electrode via a junction capacitance (e.g., the above-mentioned junction capacitances C _A and C _B ),
The power receiving side is
a first layer made of an insulating elastic material (e.g., rubber 121 and elastic adhesive layer 122 in FIG. 2 ) on a surface of the power receiving electrode facing the power transmitting electrode, a second layer made of a flexible thin-plate conductor (e.g., thin-plate electrode 123 in FIG. 2 ), and a conductive elastic material (e.g., spring-shaped conductor 124 in FIG. 2 ) connecting an end of the second layer to the power receiving electrode,
an insulating film is disposed on a surface of the second layer facing the power transmitting electrode;
When the second layer is in contact with or in close proximity to the power transmitting electrode, power from the power transmitting electrode is received by the power receiving electrode via the second layer and the conductive elastic body.

Moreover, the second layer is disposed in a plurality of layers on the surface of the first layer,
When the power receiving side is pressed against the power transmitting side, each of the plurality of second layers can change shape to match the shape of the surface of the power transmitting electrode and come into contact with the surface of the power transmitting electrode.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
A FET (field effect transistor) disposed on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
It operates as a flyback inverter that oscillates a square wave.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
A FET (field effect transistor) disposed on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
It acts as a forward inverter that oscillates a square wave.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
A full bridge circuit including four FETs (field effect transistors) that oscillates a pseudo square wave is provided.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
a full bridge circuit having four FETs (field effect transistors) and a resonant circuit, the full bridge circuit being arranged on the primary side of the transformer and configured to oscillate a square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
a push-pull circuit having two FETs (field effect transistors) arranged on the primary side of the transformer and oscillating a pseudo square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
a half-bridge circuit having two FETs (field effect transistors) and two capacitors, the half-bridge circuit being arranged on the primary side of the transformer and oscillating a pseudo square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

In addition, there are two combinations of the power transmitting electrodes and the power receiving electrodes that form the junction capacitance (for example, the above-mentioned junction capacitances C _A and C _B ),
The power transmitting side includes:
Transformer and
Two FETs (field effect transistors) and a resonant circuit that oscillate a square wave are arranged on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
The power transmission device may further include a control means (for example, the power transmission control circuit 111 in FIG. 13) for controlling the operation of the power transmission side.

11: power transmitting electrode, 12: power receiving electrode, 111: power transmitting side control circuit, 121: rubber, 122: elastic adhesive layer, 123: thin plate electrode, 124: spring-shaped conductor, 125: insulating film, 126: power receiving side control circuit, L: coil, C: capacitor, V: DC power supply, T: transformer, C _A , C _B : junction capacitance, D: diode, Q: FET (field effect transistor)

Claims (9)

A power supply system including a power transmitting side having a power transmitting electrode that transmits power from a power source, and a power receiving side having a power receiving electrode that receives the power transmitted from the power transmitting electrode via a junction capacitance,
The power receiving side is
a first layer made of an insulating elastic material, a second layer made of a flexible thin-plate-shaped conductor, and a conductive elastic material connecting an end of the second layer to the power receiving electrode, on a surface of the power receiving electrode facing the power transmitting electrode;
an insulating film is disposed on a surface of the second layer facing the power transmitting electrode;
When the second layer is in contact with or in close proximity to the power transmitting electrode, power from the power transmitting electrode is received by the power receiving electrode via the second layer and the conductive elastic body.
Power supply system. the second layer is disposed on a surface of the first layer in a plurality of layers,
When the power receiving side is pressed against the power transmitting side, each of the second layers changes shape to come into contact with the surface of the power transmitting electrode in accordance with the shape of the surface of the power transmitting electrode.
The power supply system according to claim 1 . The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
A FET (field effect transistor) disposed on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
It operates as a flyback inverter that oscillates a square wave.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
A FET (field effect transistor) disposed on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
It acts as a forward inverter that oscillates a square wave.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
A full bridge circuit including four FETs (field effect transistors) that oscillates a pseudo square wave is provided.
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
a full bridge circuit having four FETs (field effect transistors) and a resonant circuit, the full bridge circuit being arranged on the primary side of the transformer and configured to oscillate a square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
a push-pull circuit having two FETs (field effect transistors) arranged on the primary side of the transformer and oscillating a pseudo square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
a half-bridge circuit having two FETs (field effect transistors) and two capacitors, the half-bridge circuit being arranged on the primary side of the transformer and oscillating a pseudo square wave;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2. The power transmitting electrode and the power receiving electrode are connected to each other in a pair of two pairs of the power transmitting electrode and the power receiving electrode, and the pair of the power receiving electrodes form the junction capacitance.
The power transmitting side includes:
Transformer and
Two FETs (field effect transistors) and a resonant circuit that oscillate a square wave are arranged on the primary side of the transformer;
Two of the power transmitting electrodes are disposed on a secondary side of the transformer;
having
The power receiving side is
A rectifier circuit;
A smoothing circuit;
having
Further comprising a control means for controlling the operation of the power transmission side.
3. The power supply system according to claim 1 or 2.

Images