JP6897231B2 - Transmitters, power receivers, wireless power supply systems and wireless power supply methods - Google Patents

Description

The examples referred to in this application relate to transmitters, power receivers, wireless power supply systems and wireless power supply methods.

In recent years, wireless power transfer (Wireless Power Transfer) technology, which supplies electric power wirelessly for power supply and charging, has attracted attention. For example, a wireless power supply system that wirelessly supplies power to various electronic devices such as mobile terminals and laptop computers, home appliances, and electric power infrastructure devices such as automobiles has been researched and developed.

Conventionally, as a wireless power supply system, a technology using electromagnetic induction or a technology using radio waves has been applied, but in recent years, it is strongly coupled as a system capable of wireless power supply while keeping a certain distance between a transmitter and a power receiver. Those using system resonance are attracting attention. As a wireless power supply using the resonance of this strong coupling system, for example, one using magnetic field resonance (magnetic field resonance) or electric field resonance (electric field resonance) is known.

For example, a wireless power feeding device using magnetic field resonance can transmit electric power of several watts or more to a place separated by several centimeters to several tens of centimeters, so that it can be used for electronic devices, home appliances, electric power infrastructure devices, and the like. It can be applied to.

By the way, conventionally, various proposals have been made for wireless power feeding using magnetic field resonance.

Japanese Unexamined Patent Publication No. 2015-043692 International Publication No. 2014/002190

Hiroki Shoki et al. (SHOKI Hiroki, et al.), "Latest Standardization Trends in Wireless Power Transmission Technology", IEICE Technical Report (Technical Report), WPT2011-19, December 2011.

By the way, in many electronic devices, power is supplied by a constant voltage by a charge control IC mounted inside, and even when wireless power supply is performed, for example, it is converted into a DC voltage (DC voltage) by a rectifying smoothing part. After that, it is converted to a predetermined voltage by a DC / DC converter. Here, as the DC / DC converter, a step-down DC / DC converter is usually used, but the input voltage of the step-down DC / DC converter is higher than the voltage directly applied to the load. Become.

Further, in order to improve efficiency, for example, it is required to apply a DC / DC converter having a high withstand voltage specification that operates even if the input voltage is high. However, depending on the price, size, etc., the withstand voltage specification of the DC / DC converter It is desired to suppress the voltage to a low voltage (for example, about + 10V with respect to the charging voltage).

According to one embodiment, a power transmission coil for transmitting power wirelessly against the power receiver, a power supply unit providing a transmission power to the transmitting coil, is provided between the power transmission coil and the power supply unit, an inductor A power transmission side variable circuit element unit including an element or a capacitor element, a power transmission side communication unit that receives power reception information indicating the received voltage and the received power from the power receiver, and a power transmission that detects the power transmission information including the information indicating the power transmission power. A power transmission having a side detection unit and a power transmission side control unit that controls the power transmission side variable circuit element unit is provided.

The electricity transmission side control section, said power receiving information, and the transmission information, the first information indicating a relationship between the received power of the power receiver and the power receiver of a load including a step-down DC / DC converter , The inductance value of the inductor element in the power transmission side variable circuit element unit is increased or based on the second information indicating the relationship between the load and the power transmission efficiency from the power transmission to the power receiver. By reducing the capacitance value of the capacitor element in the power transmission side variable circuit element unit, the power receiving voltage of the power receiving device is controlled to be reduced.

The disclosed transmitters, power receivers, wireless power supply systems and wireless power supply methods have the effect of being able to reduce the received voltage and improve efficiency.

FIG. 1 is a block diagram schematically showing an example of a wireless power feeding system. FIG. 2 is a diagram for explaining the relationship between the efficiency characteristic with respect to the load value and the received power characteristic when a constant power supply voltage is supplied. FIG. 3 is a diagram for explaining the positional relationship between the power transmission coil and the power reception coil. FIG. 4 is a diagram for explaining the relationship between the efficiency characteristic with respect to the load value and the received power characteristic when a constant power supply voltage is supplied when the wireless power feeding coil is optimally designed. FIG. 5 is a block diagram schematically showing a first embodiment of the wireless power feeding system. FIG. 6 is a diagram for explaining the effect of the power transmission side variable circuit element unit in the wireless power feeding system shown in FIG. 5 (No. 1). FIG. 7 is a diagram for explaining the effect of the power transmission side variable circuit element unit in the wireless power feeding system shown in FIG. 5 (No. 2). FIG. 8 is a block diagram schematically showing a second embodiment of the wireless power feeding system. FIG. 9 is a block diagram showing a configuration example of a power transmission side variable circuit element unit in the wireless power feeding system shown in FIG. FIG. 10 is a block diagram schematically showing a third embodiment of the wireless power feeding system. FIG. 11 is a block diagram schematically showing a fourth embodiment of the wireless power feeding system. FIG. 12 is a flowchart for explaining an example of processing in the wireless power feeding system of the present embodiment. FIG. 13 is a flowchart for explaining another example of processing in the wireless power feeding system of the present embodiment.

First, an example of a wireless power supply system and its problems will be described with reference to FIGS. 1 to 4 before detailing examples of a transmitter, a power receiver, a wireless power supply system, and a wireless power supply method. FIG. 1 is a block diagram schematically showing an example of a wireless power feeding system. As shown in FIG. 1, the wireless power feeding system includes a power transmission system (transmitter 101, power transmission side) and a power reception system (power receiver 102, power reception side).

The transmitter 101 includes, for example, a power supply unit 110 and a transmission coil 111, and the power receiver 102 includes, for example, a power receiving coil 121, a rectifying smoothing unit (rectifying smoothing circuit) 122, and a DC / DC converter (DC / DC converter: It includes a DD converter (123) and a load (eg, a battery) 124. Here, reference numeral 120 indicates an apparent load including the DC / DC converter 123 and the load 124. Further, the transmitter 101 (transmission coil 111) wirelessly transmits power to the receiver 102 (power receiving coil 121) by using electromagnetic induction or resonance of a strong coupling system such as magnetic field resonance or electric field resonance.

In the power transmission 101, the power supply unit 110 supplies electric power to the power transmission coil 111. Further, in the power receiving device 102, the power receiving coil 121 receives the electric power from the power transmitting coil 111, and the rectifying smoothing unit 122 rectifies and smoothes the AC voltage (electric power) from the power receiving coil 121. The DC / DC converter 123 converts the output voltage of the rectifying smoothing unit 122 into a predetermined voltage and applies it to the load 124.

As shown in FIG. 1, for example, from the power supply unit 110 to the transmission coil 111, the power receiving coil 121, and the rectifying smoothing unit 122 are processed as AC voltage, and from the rectifying smoothing unit 122, the DC / DC converter 123 and the load. Up to 124, it is processed as a DC voltage. In FIG. 1, the reference code Pin is the input power of the power transmission coil 111 (output power of the power supply unit 110), Vamp is the output voltage (voltage level) of the power supply unit 110, and V'out is the output of the rectifying smoothing unit 122. The voltage (input voltage of DC / DC converter 123) is shown.

Further, the reference code Vout is the output voltage of the DC / DC converter 123 (applied voltage of the load 124), P'out is the output power of the rectifying smoothing unit 122 (input power of the DC / DC converter 123), and Pout is. The output power of the DC / DC converter 123 is shown. Further, the reference reference numeral _RL indicates, for example, the load value (impedance) of the load (battery) 124 to be charged, and _RL is the input impedance of the DC / DC converter 123, that is, apparently. The load value of the load 120 is shown.

By the way, in many electronic devices, power is supplied at a constant voltage (for example, 5V for smartphones and 12V or 19V for notebook computers) by a charge control IC mounted inside. Therefore, even when wireless power supply is performed, after the power receiving coil 121 receives power by alternating current, it is converted into a DC voltage (DC voltage) by the rectifying smoothing unit 122, and further, it is determined by passing through the DC / DC converter 123. Output the voltage of.

As the DC / DC converter 123, for example, a step-down type is often used from the viewpoint of cost and availability. In this case, for example, from the value (impedance) _{RL of the load 124 to be charged.} Also, it always acts as an _{apparently higher value (R'L).} Here, assuming that the loss of the DC / DC converter 123 is negligible, because it is _{Pout ≒ P'out, R L = Vout} 2 / Pout, R 'L = V'out 2 / P'out , and the step-down when applying type DC / DC converter _{123, R 'L> R L} , the V'out> Vout. That is, when the load value of the load 120 of the apparent (R _'L) is high, the input voltage V'out of the DC / DC converter 123 is high.

FIG. 2 is a diagram for explaining the relationship between the efficiency characteristic with respect to the load value and the received power characteristic when a constant power supply voltage is supplied. Generally, the power supply performance (transmission efficiency) of wireless power transmission is affected by the load value in the power receiving system. That is, as shown in FIG. 2, the efficiency has an optimum point for a certain load value, and is usually maximum (for example, 86%) near the representative load value (for example, 25Ω) of the electronic device to be charged. ) Is designed to be.

Further, when a step-down DC / DC converter is used as the DC / DC converter 123, a region on the higher load side than the load value (for example, Rpmax = 219Ω) that gives the maximum value of the above-mentioned received power characteristic (in FIG. 2). It works only in the hatch area). Therefore, in order to secure efficiency characteristics and avoid overvoltage, for example, it is preferable to set Rpmax near or below the load value of the electronic device to be charged. Specifically, for example, when considering a tablet terminal that requires a power of 14 W at an operating voltage of 19 V, the input voltage V'out of the DC / DC converter 123 is V'out> (14 × Rpmax) ^1/2. = (14 × 219) ^1/2 ≈ 56 [V]. That is, the efficiency (transmission efficiency) drops from 86% to 68% at the load value (219Ω) that gives the maximum value of the received power characteristic compared to the operating point near the representative load value (25Ω), and even at 56V. The application of a DC / DC converter with a high withstand voltage specification that can be operated will be required. When the output voltage of the DC / DC converter 123 is 19V, it is desired that the withstand voltage specification be suppressed to, for example, + 10V (about 29V).

Further, when the arrangement of the power receiving device 102 changes, that is, the positional relationship of the power receiving coil 121 with respect to the power transmission coil 111 changes, for example, switching control is dynamically performed according to a change in the characteristics of the wireless power supply, which is desired. It is preferable to ensure the performance. FIG. 3 is a diagram for explaining the positional relationship between the power transmission coil and the power reception coil, and FIG. 4 is a diagram showing efficiency characteristics with respect to a load value and power reception power when a constant power supply voltage is supplied when the wireless power supply coil is optimally designed. It is a figure for demonstrating the relationship of a characteristic. Here, FIG. 3A shows a state in which the positional relationship between the power transmission coil 111 and the power reception coil 121 is facing each other (when the coupling strength is 1 (100%)), and FIG. 3B shows the power transmission coil 111. The case where the positional relationship of the power receiving coil 121 is misaligned (coupling strength is 2/3) is shown. Further, in FIG. 4, the characteristic curves L11 and L12 are the cases of the facing state of FIG. 3 (a), and the characteristic curves L21 and L22 are the cases of the misalignment of FIG. 3 (b). The characteristic curves L11 and L21 show the relationship between the load and the efficiency, and the characteristic curves L12 and L22 show the relationship between the load and the received power (power received when a constant power supply voltage is supplied).

As shown in the characteristic curves L11 and L12 of FIG. 4, when the power transmission coil 111 and the power reception coil 121 are in a facing state (FIG. 3 (a)), Rpmax0 is about 28Ω in the tablet terminal in which the wireless power supply coil is optimally designed. Therefore, the efficiency can be set to 81% when V'out0> 20V. That is, by optimally designing the wireless power feeding coil (power transmitting coil 111 and power receiving coil 121), the Rpmax in FIG. 2 is reduced from 219Ω to 28Ω, and the efficiency is improved and the withstand voltage specification of the DC / DC converter is lowered. I see that it is possible. However, there is a limit to reducing Rpmax while considering the balance with the efficiency characteristics, and it is considered difficult to improve the characteristics by relying only on this coil design.

As shown in the characteristic curves L21 and L22 of FIG. 4, when the power transmission coil 111 and the power reception coil 121 are misaligned (FIG. 3 (b)), the Rpmax1 is about 63Ω in the tablet terminal in which the wireless power supply coil is optimally designed. Therefore, the efficiency can be set to 82% when V'out1> 30V. That is, it can be seen that by optimally designing the power transmission coil 111 and the power reception coil 121, even when there is a misalignment (coupling coefficient is 2/3), it is possible to cope with it as it is. Here, when the positional relationship between the power transmission and the power receiving coil is in a facing state, for example, since there is a margin in V'out 0, efficiency improvement can be expected by shifting the operating point to the high load side (right side in FIG. 4). On the other hand, with regard to the presence of misalignment, it cannot be said that V'out 1 is sufficiently reduced, considering the margin for, for example, the case where excess power is suddenly supplied. Therefore, even when the coupling strength between the power transmitting and receiving coils changes (for example, when the operator moves the tevret terminal), it is desired that the characteristics can be adaptively switched according to such a change. There is.

Hereinafter, examples of a transmitter, a power receiver, a wireless power supply system, and a wireless power supply method will be described in detail with reference to the accompanying drawings. FIG. 5 is a block diagram schematically showing a first embodiment of the wireless power feeding system. As shown in FIG. 5, the wireless power supply system includes a power transmission system (transmitter 1, power transmission side) and a power reception system (power receiver 2, power reception side).

The power transmission 1 includes, for example, a power supply unit 10, a power transmission coil 11, and a power transmission side variable circuit element unit 12. The power receiving device 2 includes, for example, a power receiving coil 21, a rectifying smoothing unit (rectifying smoothing circuit) 22, a DC / DC converter (DC / DC converter: DD converter) 23, and a load (for example, a battery) 24. Here, reference numeral 20 indicates an apparent load (load seen from the rectifying smoothing unit 22) including the DC / DC converter 23 and the load 24. The power transmission coil 11 includes a resonance coil (transmission resonance coil) 11a and a drive coil (power supply coil) 11b, and the power reception coil 21 includes a resonance coil (power reception resonance coil) 21a and a load coil (power extraction coil) 21b.

The rectifying and smoothing unit 22 rectifies and smoothes the AC voltage from the power receiving coil 21 (load coil 21b) and outputs it to the DC / DC converter 23. The DC / DC converter 23 converts the output voltage of the rectifying / smoothing unit 22 into a predetermined voltage and applies it to the load 24. In FIG. 5, reference numeral Pin is the output power of the power supply unit 10, Vamp is the output voltage of the power supply unit 10, V'out is the output voltage of the rectifying smoothing unit 22 (input voltage of the DC / DC converter 23), and , Vout indicates the output voltage of the DC / DC converter 123 (the applied voltage of the load 24). Further, reference numeral P'out the output power of the rectifying and smoothing portion 22, Pout is the output power of the DC / DC converter 23, R _L is the load (battery) 24 of the load value (impedance), and, R _'L is DC The input impedance (load value of the apparent load 20) of the / DC converter 23 is shown.

Here, the transmitter 1 and the receiver 2 transmit energy (power) from the transmitter 1 to the receiver 2 by, for example, magnetic field resonance between the resonance coil 11a and the resonance coil 21a. The power transmission from the resonance coil 11a to the resonance coil 21a may use not only magnetic field resonance but also strong coupling resonance such as electric field resonance. Further, with reference to FIG. 10, as will be described in detail later, the power transmission from the transmitter 1 to the receiver 2 may be, for example, using electromagnetic induction or the like.

The power supply unit 10 applies electric power (Pin) to the drive coil 11b via the power transmission side variable circuit element unit 12, and the drive coil 11b drives the resonance coil 11a. The power transmission side variable circuit element unit 12 includes at least one of an inductor element Lm and a capacitor element (capacitor) Cm. Then, the power transmission side variable circuit element unit 12 controls, for example, the value (inductance) of the inductor element, the value (capacitance) of the capacitor element, and the like based on the power reception information transmitted from the power receiver 2 via wireless communication. ..

That is, in the first embodiment, the power transmission side variable circuit element unit 12 of the power transmission system inserts the inductor element Lm or the capacitor element Cm between the power supply unit 10 and the power transmission coil 11 (drive coil 11b), or the power supply. The unit 10 and the drive coil 11b are short-circuited. As a result, Rpmax can be reduced (variable) by changing the received power characteristic when a constant power supply voltage is supplied while maintaining the efficiency characteristic.

6 and 7 are diagrams for explaining the effect of the power transmission side variable circuit element unit in the wireless power feeding system shown in FIG. 5, and is an example of a tablet terminal in which a power of 14 W is required at an operating voltage of 19 V. is there. Here, FIG. 6A shows the case of the facing state, the characteristic curve L11 shows the relationship between the load and the efficiency in the facing state, and the characteristic curves L121 to L125 are the load and the received power in the facing state. The relationship of (power received when a constant power supply voltage is supplied) is shown. Further, FIG. 6B shows a case where there is a misalignment (coupling coefficient: 2/3), the characteristic curve L21 shows the relationship between the load and the efficiency when there is a misalignment, and the characteristic curves L221 to L225 are the positions. The relationship between the load and the received power in the presence of deviation is shown. The characteristic curves L121 to L125 and L221 to L225 differ in the values of the inductor element Lm or the capacitor element Cm inserted by the power transmission side variable circuit element unit 12. That is, L121 and L221 are Cm = 0.3 μF, L122 and L222 are Cm = 0.5 μF, L123 and L223 are directly connected (THRU: short-circuited without inserting Cm and Lmw), L124 and L224 are Lm = 7.5 μH, and L125 and L225 are for the case where Lm = 20 μH.

Further, FIG. 7A shows the maximum Rpmax (maximum received power characteristic) with respect to the circuit element (Lm = 20 μH, Lm = 7.5 μH, THRU, Cm = 0.5 μF, Cm = 0.3 μF) to be inserted in the face-to-face state. The load value that gives the value), V'out (input voltage of the DC / DC converter 23), and efficiency are shown. Further, FIG. 7B shows Rpmax, V'out and efficiency with respect to the circuit element to be inserted (Lm = 20 μH, Lm = 7.5 μH, THRU, Cm = 0.5 μF, Cm = 0.3 μF) in the case of misalignment. Is shown. In addition, in FIG. 7A and FIG. 7B, considering the application of the step-down DC / DC converter 23, when Rpmax < _RL (for example, _RL = 25Ω), V'out> Vout. (For example, Vout = 19V), so Rpmax = 25Ω is used for estimation.

As shown in FIGS. 6A and 6B, for example, by increasing the value of the inductor element Lm inserted between the power supply unit 10 and the drive coil 11b by the power transmission side variable circuit element unit 12, the value of the inductor element Lm is increased. It can be seen that Rpmax can be reduced. However, as the value of Lm is increased, the maximum value of the received power gradually decreases. Further, regarding the capacitor element Cm to be inserted, the behavior is opposite to that of the inductor element Lm, and by reducing the value of Cm, Rpmax is lowered.

Further, as is clear from the comparison between FIGS. 6 (a) and 6 (b), even when the transmitter 1 and the receiver 2 (resonant coils 11a and 21a) are misaligned, the value of Lm or Cm is set. By adjusting, the received voltage can be reduced and the efficiency can be improved. That is, it is possible to adjust V'out and efficiency within an appropriate range while controlling Rpmax based on a state such as a positional deviation between the transmitter 1 and the receiver 2.

Further, as shown in FIG. 7A, when the power transmitter 1 and the power receiver 2 are in a facing state, for example, when there is a margin in the upper limit value of V'out, the power transmission side variable circuit element unit 12 provides a capacitor. Efficiency can be improved by increasing the value of the element Cm. Further, as shown in FIG. 7B, when the power transmitter 1 and the power receiver 2 are misaligned, for example, the Rpmax is increased by increasing the value of the inductor element Lm by the power transmission side variable circuit element unit 12. It can be reduced and the V'out can be suppressed to the 20V level (lower than 19V + 10V). By continuously executing the above-mentioned processing during the wireless power supply, for example, even if the characteristics change depending on the placement (arrangement) of the power receiver 2, the appropriate V'out level can be obtained. It is possible to achieve high efficiency at the same time.

FIG. 8 is a block diagram schematically showing a second embodiment of the wireless power feeding system. As is clear from the comparison between FIG. 8 and FIG. 5 described above, in the wireless power feeding system of the second embodiment, the power transmission 1 further includes a power transmission side detection unit 13, a power transmission side control unit 14, and a power transmission side communication unit 15. including. The power transmission side detection unit 13 detects the power transmission side information, and the power transmission side control unit 14 controls the power transmission side variable circuit element unit 12 based on the power transmission power information and the power reception information. The power receiving information is input to the power transmission side control unit 14 from the power transmission side communication unit 15 that wirelessly communicates with the power receiver 2 (transmission system), for example.

The power receiving device 2 includes a power receiving side detection unit 25, a power receiving side control unit 26, and a power receiving side communication unit 27 in addition to the power receiving coil 21, the rectifying smoothing unit 22, the DC / DC converter 23, and the load 24 described above. The power receiving side detection unit 25 detects DC / DC conversion information (power receiving information) including the input voltage V'out and the output voltage Vout of the DC / DC converter 23, and detects the power receiving side control unit 26 and the power receiving side communication unit. It is transmitted to the transmitter 1 (transmission side communication unit 15) via 27. Here, for communication between the power transmission side communication unit 15 and the power reception side communication unit 27, for example, a DSSS wireless LAN or Bluetooth (Bluetooth (registered trademark)) compliant with IEEE 802.11b can be used. It is not limited to these.

The power transmission side control unit 14 is, for example, DC / DC conversion information (power reception information) including V'out and Vout sent from the power reception side communication unit 27 of the power reception system via the power transmission side communication unit 15, and power transmission. The power transmission side variable circuit element unit 12 is controlled based on the power transmission power information from the side detection unit 13. That is, the power transmission side control unit 14 adjusts (switches) the values of the inductor element Lm or the capacitor element Cm, or short-circuits the power transmission side variable circuit element unit 12 without inserting the Cm and Lmw. As a result, Rpmax can be reduced by changing the received power characteristic when a constant power supply voltage is supplied while maintaining the efficiency characteristic. Further, the power transmission side control unit 14 is, for example, the output of the power supply unit 10 under the condition that the input voltage V'out of the DC / DC converter 23 is equal to or less than a predetermined value based on the above-mentioned power reception information and power transmission power information. It is also possible to increase the voltage Vamp to improve efficiency.

FIG. 9 is a block diagram showing a configuration example of the power transmission side variable circuit element unit in the wireless power feeding system shown in FIG. 8, and FIGS. 9 (a) and 9 (a) and FIG. It is shown as FIG. 9 (b).

As shown in FIG. 9A, the power transmission side variable circuit element unit 12 of the first configuration example includes a plurality of inductor elements Lm1 to Lmn, a plurality of capacitor elements Cm1 to Cmn, and a plurality of elements corresponding to each. It includes a selection switch element and a short-circuit switch element that short-circuits between input and output. Here, the inductor elements Lm1 to Lmn and the capacitor elements Cm1 to Cmn have different inductances and capacitances, for example. That is, the power transmission side variable circuit element unit 12 of the first configuration example is composed of a plurality of lines so that different circuit constants can be selectively switched.

The power transmission side control unit 14 turns on any one of the element selection switch elements or the short circuit switch elements. As a result, the inductor element or capacitor element corresponding to the turned-on element selection switch element is inserted between the power supply unit 10 and the drive coil 11b, or the power supply unit 10 and the drive coil 11b are short-circuited ( (Directly connected).

As shown in FIG. 9B, the power transmission side variable circuit element unit 12 of the second configuration example includes the variable inductor element Lm, and the power transmission side control unit 14 controls the value of the variable inductor element Lm. It has become. Needless to say, the variable capacitor element Cm can be applied instead of the variable inductor element Lm. That is, in the power transmission side variable circuit element unit 12 of the second configuration example, different circuit constants can be adjusted by the variable inductor element Lm or the variable capacitor element Cm. It should be noted that the configuration of the power transmission side variable circuit element unit 12 is not limited to that of FIGS. 9 (a) and 9 (b) described above, and it goes without saying that various known configurations can be applied. Nor.

As described above, the power transmission side control unit 14 in the power transmission 1 (transmission system) of the second embodiment is, for example, the power transmission side variable circuit element unit 12 based on the detected information (power reception information, power transmission power information). The variable circuit elements (Lm1 to Lmn, Cm1 to Cmn; Lm, Cm) are switched or adjusted (controlled). Further, the power transmission side control unit 14 can realize an appropriate wireless power supply state by adjusting the output voltage Vamp of the power supply unit 10. Here, the power transmission side control unit 14 holds, for example, a load dependence table of efficiency and received power characteristics as shown in FIGS. 6A and 6B described above in the internal memory 140 to transmit power. It can also be used together (see) when controlling the side variable circuit element unit 12. By continuously executing this series of controls during the wireless power supply, for example, an appropriate V'is applied to the displacement of the transmitter 1 and the receiver 2 and the change in the placement. As mentioned above, it is possible to achieve both the out level and high efficiency at the same time.

FIG. 10 is a block diagram schematically showing a third embodiment of the wireless power feeding system, and shows an example of the wireless power feeding system to which the electromagnetic induction method is applied. As is clear from the comparison between FIG. 10 and FIG. 8 described above, in the wireless power feeding system of the third embodiment, the power receiving coil 21 of the power receiving device 2 receives the power from the power transmitting coil 11 of the power transmitting device 1 by the electromagnetic induction method. It is supposed to receive. That is, the present embodiment is not limited to the one to which the resonance of the strong coupling system such as the magnetic field resonance and the electric field resonance is applied, but may be the one to which the electromagnetic induction is applied, and is widely applied to various wireless power feeding systems. be able to.

In the third embodiment shown in FIG. 10, the configuration other than the power receiving coil 21 of the power receiving device 2 receiving the power from the power transmitting coil 11 of the power transmission 1 by the electromagnetic induction method is the second embodiment of FIG. 8 described above. It is the same as the example, and the description thereof will be omitted.

FIG. 11 is a block diagram schematically showing a fourth embodiment of the wireless power feeding system, in which the power transmitting side variable circuit element unit 12 in the power transmission 1 is deleted, and instead, the power receiving side variable with respect to the power receiving device 2 is deleted. The circuit element unit 28 is provided. That is, in the fourth embodiment, for example, the power receiving side variable circuit element unit 28 corresponding to the power transmitting side variable circuit element unit 12 described with reference to FIGS. 5 to 9 is used as the load coil (power extraction coil) in the power receiving device 2. ) 21b and the rectifying smoothing portion 22.

The power receiving side control unit 26 receives, for example, power receiving information (information including V'out and Vout) from the power receiving side detection unit 25 and controls (switches or adjusts) the power receiving side variable circuit element unit 28. Here, the power receiving side control unit 26 receives, for example, the transmitted power information from the power transmission 1 (transmission side communication unit 15) via the power receiving side communication unit 27, and receives power based on the power receiving information and the transmitted power information. It is also possible to control the side variable circuit element unit 28. At this time, the power transmission side control unit 14 receives, for example, power reception information from the power receiver 2 (power reception side communication unit 27) via the power transmission side communication unit 15 and controls the output voltage Vamp of the power supply unit 10.

Here, for example, the transmitter 1 in the second embodiment described above can be applied as the transmitter 1 in the wireless power feeding system of the fourth embodiment. In this case, in the power transmission system, the power transmission side control unit 14 controls the power transmission side variable circuit element unit 12 and the power supply unit 10, and in the power reception system, the power reception side control unit 26 controls the power reception side variable circuit element unit 28. Become. Needless to say, the above-mentioned first to fourth embodiments can be combined, modified and modified in various ways.

FIG. 12 is a flowchart for explaining an example of processing in the wireless power feeding system of the present embodiment, and is a case where the output voltage (input voltage of the DC / DC converter 23) V'out of the rectifying smoothing unit 22 is controlled. This is for explaining an example of processing. As shown in FIG. 12, when the process starts, the power transmission system (power transmission 1, power transmission side) establishes communication with the power reception system (power reception device 2, power reception side) in step ST1, and further, step ST2. Proceed to, perform initial settings (for example, THRU, Vamp level, etc.) and start output (power transmission).

On the other hand, in the power receiving system, in step ST21, communication with the power transmission system is established, and further, in step ST22, it is determined whether or not the power is received by the load 24. Here, the processing of step ST1 of the power transmission system and the processing of step ST21 of the power receiving system correspond to the authentication of the power transmitting device 1 and the power receiving device 2 and the confirmation of their respective specifications. If it is determined in step ST22 that the power has been received by the load 24, the process proceeds to step ST23 to transmit the power reception information to the power transmission system.

In the power transmission system, it is determined in step ST3 whether or not the information from the power receiving system has been received, and when the power receiving information is transmitted to the power transmission system in step ST23 of the power receiving system, it is determined that the information from the power receiving system has been received in step ST3. Proceed to step ST4. In step ST4, the transmission power is measured (detected) and the efficiency is calculated, and the process proceeds to step ST7. Further, in step ST3, if it is determined that the information from the power receiving system has not been received, the process proceeds to step ST5, and it is determined whether or not the specified number of times has been exceeded. If it is determined in step ST5 that the specified number of times has not been exceeded, the process proceeds to step ST6, the output level of the power supply (output voltage Vamp of the power supply unit 10) is updated, and the process returns to step ST3. If it is determined in step ST5 that the specified number of times has been exceeded, the process proceeds to step ST16, the end is displayed, and the power transmission (output) end notification is notified to the power receiving system to end the process. Here, the transmission end notification from the power transmission system to the power receiving system is processed by the power receiving system as well, if it is determined that the end notification has been given by the determination of whether or not the end notification has been given in step ST27 of the power receiving system. If it is determined in step ST27 of the power receiving system that there is no end notification, the process returns to step ST25, which will be described later, and the process is continued.

In step ST7 in the power transmission system, it is determined whether the output voltage (input voltage of the DC / DC converter 23) V'out of the rectifying and smoothing unit 22 of the power receiving system is equal to or higher than the specified value, and V'out is equal to or higher than the specified value. If it is determined, the process proceeds to step ST8. In step ST8, it is determined whether or not the output level (Vamp) of the power supply can be reduced, and if it is determined that the Vamp can be reduced, the process proceeds to step ST9, the Vamp is reduced, and the process proceeds to step ST12. Further, if it is determined in step ST7 that V'out is not equal to or higher than the specified value, the process proceeds to step ST12 as it is.

Further, if it is determined in step ST8 that the reduction of Vamp is not possible, the process proceeds to step ST10, and whether or not the circuit element can be switched, that is, whether or not the circuit element can be switched by the power transmission side variable circuit element unit 12. To judge. If it is determined in step ST10 that the circuit element can be switched (for example, the value of the inductor element Lm is reduced or the value of the capacitor element Cm is reduced), the process proceeds to step ST11.

In step ST11, the variable circuit element is switched, that is, the circuit element is controlled (switching or adjustment: Lm small or Cm small) by the power transmission side variable circuit element unit 12. Further, in step ST10, if it is determined that the circuit element cannot be switched, the process proceeds to step ST16, the end is displayed, and the power transmission end notification is notified to the power receiving system to end the process. Here, the switching of the circuit element by the power transmission side variable circuit element unit 12 controls the value of the inductor element or the capacitor element, for example, as described above with reference to FIGS. 5 to 9. Further, for example, in the fourth embodiment shown in FIG. 11, in the power receiving system, the circuit element is switched by the power receiving side variable circuit element unit 28.

Further, the process proceeds to step ST12 to communicate with the power receiving system, and the process proceeds to step ST13 to determine whether or not information has been received from the power receiving system. At this time, in step ST25, the power receiving system determines whether or not there is an information request from the power transmission system, and if it is determined that there is an information request from the power transmission system, the process proceeds to step ST26 to transmit the power receiving information to the power transmission system. To step ST27. If it is determined in step ST25 of the power receiving system that there is no information request from the power transmission system, the process of step ST25 is continued until there is an information request.

If it is determined in step ST13 of the power transmission system that information has been received from the power receiving system, the process returns to step ST4, the above processing is repeated, and if it is determined that no information has been received from the power receiving system, the process proceeds to step ST14. In step ST14, it is determined whether or not the specified number of times has been exceeded, and if it is determined that the specified number of times has not been exceeded, the process proceeds to step ST15, the Vamp (output voltage of the power supply unit 10) is updated, and the process returns to step ST13. Further, in step ST14, if it is determined that the specified number of times has been exceeded, the process proceeds to step ST16, the end is displayed, and the power transmission end notification is notified to the power receiving system to end the process. In step ST27 of the power receiving system, it is determined whether or not there is a power transmission end notification from the power transmission system, and if it is determined that there is a power transmission end notification, the power receiving system also ends the process and determines that there is no end notification. The process returns to step ST25 and the process is continued. As described above, according to the process shown in FIG. 12, the input voltage V'out of the DC / DC converter 23 in the power receiving system is increased by controlling the value of the inductor element or the capacitor element by the power transmission side variable circuit element unit 12. It is possible to prevent the value from exceeding the specified value.

FIG. 13 is a flowchart for explaining another example of the processing in the wireless power feeding system of the present embodiment, and steps ST17 and ST18 of the power transmission system are added to the flowchart shown in FIG. That is, in the flowchart shown in FIG. 13, when it is determined in step ST7 of FIG. 12 that V'out is not equal to or higher than the specified value, the process of steps ST17 and ST18 is performed instead of proceeding directly to step ST12, and then the process is performed. Proceed to step ST12.

In step ST17, if it is determined that the circuit element can be switched (Lm large or Cm large) by the power transmission side variable circuit element unit 12, the process proceeds to step ST18, and the circuit element is controlled (switched) by the power transmission side variable circuit element unit 12. Or adjust: Lm large or Cm large). As a result, not only V'out can be reduced, but also efficiency (transmission efficiency) can be improved. Then, the process proceeds to step ST12, and the same processing as described with reference to FIG. 12 is performed. That is, according to the process shown in FIG. 13, not only the V'out by the process of FIG. 12 is prevented from exceeding the specified value, but also if the V'out is not equal to or more than the specified value (if there is a margin), It is also possible to improve efficiency.

Although the embodiments have been described above, all the examples and conditions described here are described for the purpose of assisting the understanding of the concept of the invention applied to the invention and the technology, and the examples and conditions described in particular are described. It is not intended to limit the scope of the invention. Nor does such a statement in the specification indicate the advantages and disadvantages of the invention. Although embodiments of the invention have been described in detail, it should be understood that various modifications, replacements and modifications can be made without departing from the spirit and scope of the invention.

1,101 Transmission 2,102 Power receiver 10,110 Power supply 11,111 Transmission coil 11,111 Transmission coil 11a Resonant coil (transmission resonance coil)
11b Drive coil (power supply coil)
12 Power transmission side variable circuit element unit 13 Power transmission side detection unit 14 Power transmission side control unit 15 Power transmission side communication unit 21,121 Power receiving coil 21a Resonant coil (power receiving resonance coil)
21b Load coil (power extraction coil)
22,122 Rectifying and smoothing unit 23,123 DC / DC converter 24,124 Load 25 Power receiving side detection unit 26 Power receiving side control unit 27 Power receiving side communication unit 28 Power receiving side variable circuit element unit 140 Memory

Claims (13)

A power transmission coil that wirelessly transmits power to a power receiver,
A power supply unit that supplies power to the power transmission coil,
A power transmission side variable circuit element unit including an inductor element or a capacitor element provided between the power supply unit and the power transmission coil, and a power transmission side variable circuit element unit.
A power transmission side communication unit that receives power reception information indicating the power reception voltage and power reception from the power receiver, and a power transmission side communication unit.
A power transmission side detection unit that detects power transmission information including information indicating the power transmission power,
The power transmission device for chromatic and a power-transmitting-side control unit that controls the power transmission side variable circuit element portion,
The electricity transmission side control section,
From the power reception information, the power transmission information, the first information showing the relationship between the load of the power receiver including the step-down DC / DC converter and the power reception of the power receiver, and the load and the power transmission. Based on the second information indicating the relationship with the power transmission efficiency to the power receiver, the inductance value of the inductor element in the power transmission side variable circuit element unit is increased, or the power transmission side variable circuit element unit in the power transmission side variable circuit element unit. By reducing the capacitance value of the capacitor element, the power receiving voltage of the power receiving device is controlled to be reduced.
A transmitter characterized by that. The first information is a load value corresponding to the inductance value or the capacitance value, which maximizes the power in the relationship between the load and the received power, and an input voltage value input to the DC / DC converter. Information that shows the relationship
The second information is information indicating the relationship between the load value and the power transmission efficiency, which corresponds to the inductance value or the capacitance value.
The transmitter according to claim 1. The power transmission side control unit controls the inductance value or the capacitance value in the power transmission side variable circuit element unit so that the power reception voltage becomes a specified value or less based on the power reception information and the first information. ,
The transmitter according to claim 1 or 2. The power transmission side control unit controls the inductance value or the capacitance value in the power transmission side variable circuit element unit so as to improve the power transmission efficiency based on the power reception information, the power transmission information, and the second information. To do,
The transmitter according to any one of claims 1 to 3, wherein the transmitter is characterized in that. The inductor element or the capacitor element of the power transmission side variable circuit element unit includes a plurality of the inductor elements having different inductance values or a plurality of the capacitor elements having different capacitance values.
The inductor element or the selected capacitor element selected based on the control by the power transmission side control unit is inserted between the power supply unit and the power transmission coil.
The transmitter according to any one of claims 1 to 4. The inductor element or the capacitor element of the power transmission side variable circuit element unit includes the inductor element whose inductance value can be changed or the capacitor element whose capacitance value can be changed.
The inductor element having the inductance value adjusted based on the control by the power transmission side control unit or the capacitor element having the adjusted capacitance value is inserted between the power supply unit and the power transmission coil.
The transmitter according to any one of claims 1 to 4. The power transmission side control unit controls the output voltage of the power supply unit based on the power reception information, the power transmission information, and the first information so that the power reception voltage does not exceed the specified value.
The transmitter according to any one of claims 3 to 6, wherein the transmitter is characterized in that. The power transmission side control unit controls the output voltage of the power supply unit based on the power reception information, the power transmission information, and the second information so as to improve the power transmission efficiency.
The transmitter according to any one of claims 1 to 7. Power is transmitted to the power receiver using electromagnetic induction or strong coupling resonance.
The transmitter according to any one of claims 1 to 8. A power receiving coil that wirelessly receives the power transmitted from the transmitter,
A rectifying and smoothing unit that rectifies and smoothes the AC voltage from the power receiving coil to a DC voltage,
A step-down DC / DC converter that converts the output voltage of the rectifying and smoothing unit to a predetermined voltage, and
A power receiving side variable circuit element unit including an inductor element or a capacitor element provided between the power receiving coil and the rectifying smoothing unit, and a power receiving side variable circuit element unit.
A power receiving side detection unit that detects power receiving information indicating the input voltage and output voltage of the DC / DC converter, and
A power receiving side control unit that controls the power receiving side variable circuit element unit,
A power receiver which have a, a power receiving side communication unit for receiving transmission information indicating the transmission power from the power transmitting device,
The power receiving side control unit
And the power receiving information, wherein the transmission information and, transmitting a first information indicating a relationship between the receiving Denden force load and the power receiver comprising the DC / DC converter from the power transmitting device and the load to the power receiver Based on the second information indicating the relationship with efficiency, the inductance value of the inductor element in the power receiving side variable circuit element unit is increased, or the capacitance value of the capacitor element in the power receiving side variable circuit element unit is increased. Is controlled so as to reduce the power receiving voltage of the power receiving device.
A power receiver characterized by that. The transmitter according to any one of claims 1 to 9,
It has the power receiver that wirelessly receives the electric power transmitted from the power transmitter.
A wireless power supply system that features. The power receiver according to claim 10 and
That having a, and the power transmission unit for transferring power wirelessly to the power receiver,
It features and to Ruwa Iyaresu power supply system that. It is a wireless power supply method that wirelessly supplies power from a transmitter to a receiver.
The power receiver
Receives the power transmitted from the transmitter wirelessly and receives it.
The AC voltage transmitted from the transmitter is rectified and smoothed to a DC voltage, and then
Power receiving information indicating the received power and the received voltage transmitted from the transmitter is transmitted to the transmitter, and the power is transmitted to the transmitter.
A step-down DC / DC converter converts the rectified and smoothed DC voltage to a predetermined voltage.
The transmitter
The power supply unit supplies electric power to the power transmission coil included in the power transmission.
The power transmission coil wirelessly transmits power to the power receiver.
The power receiving information is received from the power receiving device, and the power receiving information is received.
Detecting a power transmission information indicating the transmission Denden force,
The power receiving information, the power transmission information, the first information showing the relationship between the load of the power receiving device including the DC / DC converter and the received power of the power receiving device, and the receiving from the load and the power transmission device. Based on the second information indicating the relationship with the power transmission efficiency to the electric appliance, the inductance value of the inductor element between the power supply unit and the power transmission coil is increased, or the power supply unit and the power transmission coil are used. By reducing the capacitance value of the capacitor element between, the power receiving voltage of the power receiving device is controlled to be reduced.
A wireless power supply method characterized by that.

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