WO2013089311A1

WO2013089311A1 - Device and method for wirelessly transmitting power by using magnetic resonant induction which are capable of sensing the movement of foreign material and wireless charging equipment

Info

Publication number: WO2013089311A1
Application number: PCT/KR2012/000703
Authority: WO
Inventors: 원윤재
Original assignee: 전자부품연구원
Priority date: 2011-12-16
Filing date: 2012-01-30
Publication date: 2013-06-20
Also published as: KR101213649B1

Abstract

The present invention relates to a device and method which are capable of sensing foreign material as the reason for a decrease in power transmission efficiency in a wireless power transmission system which uses magnetic resonant induction. At least one of a current sensor, a voltage sensor, and a phase sensor is installed in the power converting unit of the wireless power transmission device, compares a reference current, a reference voltage, and a reference phase with a measured current, a measured voltage, and a measured phase, senses a foreign material, and informs the user of the sensed result. Thus, since it is possible to eliminate foreign material and to charge normally, it is possible to increase power transmission efficiency and prevent energy waste. In addition, it is possible to avoid power waste and to protect a system by stopping charging if charging efficiency decreases to below a predetermined limit. On the other hand, if it is determined from the comparison result that there is a change in current or voltage but there are no foreign materials and the equipment to be charged has moved, impedance matching is performed again.

Description

Wireless power transmission apparatus and method using a magnetic resonance induction method that can detect the movement of foreign matter and wireless charger

The present invention relates to a wireless power transmission apparatus and method, and more particularly to a wireless power transmission apparatus and method using a magnetic resonance induction method that can detect the movement of foreign matter or wireless charger.

As a wireless power transmission technology for wirelessly transmitting energy, a wireless charging system using magnetic induction is used.

For example, electric toothbrushes or wireless shavers are charged with the principle of electromagnetic induction. Recently, wireless charging products for charging mobile devices such as mobile phones, PDAs, MP3 players, and notebook computers using electromagnetic induction have been introduced. .

However, the magnetic induction method of inducing current through a magnetic field from one coil to another is very sensitive to the distance and relative position between the coils, so that the transmission efficiency drops rapidly even if the distance between the two coils is slightly dropped or twisted. Accordingly, this magnetic induction charging system can only be used in a short distance of several cm or less.

On the other hand, US Patent 7,741,735 discloses a non-radiative energy transfer method based on the attenuation wave coupling of the resonant field. This is because two resonators with the same frequency do not affect other non-resonators around them, but they tend to couple with each other and are introduced as a technology that can transfer energy over a long distance compared to conventional electromagnetic induction. .

In the technique of wirelessly transmitting energy by using resonance, if the frequency between the transmitting antenna and the receiving antenna does not match, the power transmission efficiency drops sharply. However, when metallic foreign matter is present between the transmitting side and the receiving side of the energy, the resonance frequency is changed due to the effect thereof, so that the matching is not performed, thereby reducing the power transmission efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described technical background, and an object thereof is to provide an apparatus and a method capable of detecting a foreign substance that causes a decrease in power transmission efficiency in a magnetic resonance induction-type wireless power transmission system.

In order to solve the above problems, the present invention provides at least one of a current sensor, a voltage sensor, and a phase sensor in a power converter of the wireless power transmission apparatus to compare the reference current, voltage, and phase with the measured current, voltage, and phase. Detect foreign objects and notify the user of the result.

A wireless power transmission apparatus according to an aspect of the present invention, a wireless power transmission device for transmitting power in a magnetic resonance induction method to an external wireless charger, an oscillator for generating a signal of a predetermined constant frequency, and generated by the oscillator A power amplifier for amplifying the signal, a matching network for frequency matching to transmit the signal amplified by the power amplifier in a magnetic resonance induction scheme, and a transmission antenna for transmitting the frequency matched signal by the matching network to the wireless charger. And a current sensor connected between the matching network and the transmitting antenna, and an output unit for outputting that a foreign matter is detected when a difference between the current sensed through the current sensor and a predetermined reference current exceeds a predetermined first threshold. It is made to include.

Here, the output unit may include one or more of a display screen for outputting the screen that the foreign matter is detected, a voice output unit for outputting a voice that the foreign matter is detected, and a warning light to warn that the foreign matter is detected.

The wireless power transmitter stops power transmission when the power transmission efficiency from the wireless power transmitter to the charger is less than a second threshold as a result of the determination based on the difference between the current sensed by the current sensor and the reference current. It may further include a magnetic field communication modem connected to the transmitting antenna.

According to another aspect of the present invention, a wireless power transmission apparatus includes an oscillator for generating a signal having a predetermined constant frequency, a power amplifier for amplifying a signal generated by the oscillator, and a signal amplified by the power amplifier. A matching network for frequency matching to transmit in an inductive manner, a transmitting antenna for transmitting a frequency matched signal by the matching network to the wireless charger, a voltage sensor connected between the matching network and the transmitting antenna, and It includes an output unit for outputting that the foreign matter is detected when the difference between the voltage detected by the voltage sensor and the predetermined reference voltage exceeds a predetermined threshold.

A wireless power transmission apparatus according to another aspect of the present invention is a wireless power transmission apparatus for transmitting power in a magnetic resonance induction method to an external wireless charger, the oscillator for generating a signal of a predetermined constant frequency, by the oscillator A power amplifier for amplifying the generated signal, a matching network for frequency matching in order to transmit the signal amplified by the power amplifier in a magnetic resonance induction method, and for transmitting the frequency matched signal by the matching network to the wireless charger. A phase sensor for detecting a phase difference between a transmitting antenna, a signal before passing through the matching network and a signal after passing through the matching network in parallel with the matching network, and a foreign object when the phase difference exceeds a predetermined threshold It includes an output unit for outputting the.

A wireless power transmission apparatus according to another aspect of the present invention is a wireless power transmission apparatus for transmitting power in a magnetic resonance induction method to an external wireless charger, the oscillator for generating a signal of a predetermined constant frequency, by the oscillator A power amplifier for amplifying the generated signal, a matching network for frequency matching in order to transmit the signal amplified by the power amplifier in a magnetic resonance induction method, and for transmitting the frequency matched signal by the matching network to the wireless charger. Foreign matter when a resistance value according to a difference between a current antenna connected between the transmitting antenna, the matching network and the transmitting antenna, and a current sensed by the current sensor and a predetermined reference current exceeds a predetermined first threshold value. Judges the presence of foreign substances to the user If the resistance value does not exceed the first threshold value, the resistance value is redetected two or more times at regular time intervals, and the second and second threshold values predetermined by the redetected resistance value are predetermined. Has a value less than the first threshold, and includes a control to control the matching network to re-perform frequency matching.

In determining whether the resistance value redetected exceeds the second threshold, the controller determines the average of the resistance value redetected two or more times, or the maximum value of the resistance value redetected two or more times. It can be determined based on the value.

In addition, the wireless power transmission device may further include a display unit for displaying the presence of foreign matters to the user.

A wireless power transmission apparatus according to another aspect of the present invention is a wireless power transmission apparatus for transmitting power in a magnetic resonance induction method to an external wireless charger, the oscillator for generating a signal of a predetermined constant frequency, by the oscillator A power amplifier for amplifying the generated signal, a matching network for frequency matching in order to transmit the signal amplified by the power amplifier in a magnetic resonance induction method, and for transmitting the frequency matched signal by the matching network to the wireless charger. When the resistance value according to the difference between the voltage sensor connected between the transmitting antenna, the matching network and the transmitting antenna, and the voltage sensed by the voltage sensor and the predetermined reference voltage exceeds the predetermined first threshold, Judges the presence of foreign substances to the user If the resistance value does not exceed the first threshold value, the resistance value is redetected two or more times at regular time intervals, and the second and second threshold values predetermined by the redetected resistance value are predetermined. Has a value less than the first threshold, and includes a control to control the matching network to re-perform frequency matching.

According to the present invention, when the wireless power transmitter detects the presence of foreign matters around the wireless power transmitter, the magnetic resonance induction method can be notified to the user so as to remove the power transmission efficiency and prevent energy waste. have. In addition, if a material that interferes with the power transmission is detected, the system can be protected by interrupting and notifying the power supply.

In addition, if the matching is changed due to the movement of the charging target device, not due to the presence of foreign matter, the matching may be performed again to increase the charging efficiency.

1 is a block diagram schematically showing the overall configuration of a multi-node wireless energy transmission system using a magnetic resonance induction method according to an embodiment of the present invention.

2 is a block diagram schematically showing the overall configuration of a wireless power transmission apparatus according to an embodiment of the present invention.

3 is a view showing a state in which foreign matter around the wireless power transmission apparatus according to an embodiment of the present invention.

4 to 7 are block diagrams illustrating configurations of a power converter of a wireless power transmitter according to various embodiments of the present disclosure.

8 is a block diagram illustrating a configuration of an output unit of a wireless power transmission apparatus according to an embodiment of the present invention.

9 is a flowchart illustrating a method for detecting a foreign substance in a wireless power transmission system according to another embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Meanwhile, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the wireless power transmission apparatus and method using a magnetic resonance induction method that can detect a foreign matter according to an embodiment of the present invention.

As shown in FIG. 1, the multi-node wireless energy transmission system using the magnetic resonance induction method according to an embodiment of the present invention includes a wireless power transmission apparatus 100 for wirelessly supplying power through the magnetic resonance induction method, and wireless power. A plurality of wireless chargers 200_1, 200_2,..., 200_N which are located at a distance from the transmission device 100 and are wirelessly supplied with power from the wireless power transmission device 100 are included.

The wireless power transmitter 100 may include wireless chargers 200_1, 200_2, 200_N, and wireless chargers 200_1, 200_2, including identification information, types, locations, or state of charge of the chargers through magnetic field communication. ..., 200_N) may be received, and power is transmitted to the wireless chargers 200_1, 200_2, .., 200_N in a self-resonance induction manner based on the charging information.

The wireless power transmission apparatus 100 may be implemented as a fixed type or a mobile type, and when implemented as a fixed type, the wireless power transmission device 100 may be installed in a furniture such as a ceiling or a table indoors, or may be installed in an implant type in a bus stop or a subway station outdoors. In addition, the wireless power transmission apparatus 100 may be installed inside a moving object such as a vehicle, a train, a subway. When the wireless power transmission apparatus 100 is implemented as a mobile, the wireless power transmission apparatus 100 may be implemented as a separate mobile apparatus or may be implemented as part of another digital device such as a cover of a notebook computer. .

The wireless chargers 200_1, 200_2, .., 200_N may include all digital devices including batteries such as various mobile terminals, digital cameras, and notebook computers, and are not easily accessible from underground, underwater, and inside buildings. It may also be an electronic device such as a sensor and a measuring instrument.

2 is a block diagram showing in more detail the overall configuration of a wireless power transmission apparatus according to an embodiment of the present invention.

As shown in FIG. 2, the wireless power transmission apparatus 100 according to an embodiment of the present invention receives power from an external power supply source and adjusts a resonance frequency band between the wireless power transmission apparatus 100 and the wireless charger 200. AC power from the power converter 120, the magnetic field communication modem 130 and the power converter 120 to perform a magnetic field communication with the wireless charger 200 using a magnetic field communication protocol to convert to AC power having a Wireless power transmission including a transmission antenna 110, a power converter 120, and a magnetic field communication modem 130 for transmitting data from the magnetic field communication modem 130 to the wireless charger 200 using a magnetic resonance induction method. It includes a control unit 140 for controlling the components of the device 100 and an output unit 150 for outputting the foreign matter detection situation.

The magnetic resonance induction method used in the multi-node wireless energy transmission system according to an embodiment of the present invention is a method of maximizing energy wireless transmission efficiency by resonance between a transmitting antenna and a receiving antenna. To this end, a resonance channel is formed by matching a resonance frequency between the wireless power transmitter 100 and the wireless charger 200 to transmit wireless power. Therefore, matching of the resonant frequency between the wireless power transmission apparatus 100 and the wireless charger 200 is an important problem. However, when foreign matter exists between the wireless power transmitter 100 and the wireless charger 200, the matching is not matched, and thus the transmission efficiency drops drastically. In particular, in the case of the wireless power transmitter implemented with a plate-shaped base station as shown in Figure 3, the foreign matter is more likely to be located around the transmitting antenna of the wireless power transmitter, and when there is a metallic foreign material such as a key, Frequency matching does not match.

Therefore, when a failure occurs in the wireless power transmission due to the presence of such foreign matter, it may be necessary to inform the user to remove the foreign matter, or in some cases, to stop the wireless charging. To this end, an embodiment of the present invention provides an apparatus and method for detecting a foreign substance present around a wireless power transmission apparatus.

4 to 6 are block diagrams illustrating configurations of a power converter of a wireless power transmitter according to various embodiments of the present disclosure.

First, referring to FIG. 4, the power converter 120 of the wireless power transmission apparatus 100 includes an oscillator 121, a power amplifier 122, a matching network 123, and a current sensor 124. The oscillator 121 generates a signal of a predetermined frequency, which is amplified by the power amplifier 122 and then frequency matched through the matching network 123 and transmitted through the transmitting antenna 110.

A current sensor 124 is connected between the matching network 123 and the transmitting antenna 110 to measure the current transmitted from the matching network 123 to the transmitting antenna 110. At this time, if foreign matter exists around the transmission antenna 110, the current flowing from the matching network 123 to the transmission antenna 110 is changed. The current sensor 124 detects such a change in current.

That is, when the difference between the current measured by the current sensor 124 and the reference current which is the steady-state current without foreign matter exceeds a predetermined first threshold value, the wireless power transmitter 100 determines that the foreign matter exists. can do. Therefore, the presence of the foreign matter can be warned to the user through the output unit (FIG. 2: 150). The output unit (FIG. 2: 150) may display the presence of a foreign substance on the screen, or may warn the user using various methods such as guiding a voice or turning on a warning light.

In addition, when the change in the current exceeds the second threshold larger than the first threshold and the charging efficiency is too low, the wireless power transmission apparatus 100 may stop the power transmission. In this case, the power transmission may be interrupted along with the presence of the foreign matter through the output unit (FIG. 2: 150).

5 shows a configuration of a power converter according to another embodiment of the present invention. In the embodiment shown in FIG. 5, a voltage sensor is used instead of a current sensor to detect the presence of foreign substances.

As shown in FIG. 5, the power converter 120 of the wireless power transmission apparatus 100 includes an oscillator 121, a power amplifier 122, a matching network 123, and a voltage sensor 125.

The voltage sensor 125 measures the voltage between the matching network 123 and the transmit antenna 110. When the difference between the measured voltage and the reference voltage, which is a voltage in a steady state without foreign matter, exceeds a predetermined threshold, the wireless power transmission apparatus 100 may determine that the foreign matter exists and notify the user. The alerting scheme, interruption of power transmission, and the like are similar to those in the above-described embodiment with reference to FIG. 4.

6 illustrates a configuration of a power converter according to still another embodiment of the present invention. In the embodiment shown in FIG. 6, a phase sensor is used to detect the presence of foreign substances.

As shown in FIG. 6, the power converter 120 includes an oscillator 121, a power amplifier 122, a matching network 123, and a phase sensor 126. The phase sensor 126 is connected in parallel with the matching network 123 to detect the phase difference of the signal before and after passing through the matching network 123.

If the phase difference exceeds a predetermined threshold, the wireless power transmission apparatus 100 may determine that there is a foreign matter, and thus, warn the user of the presence of the foreign matter through the output unit (FIG. 2: 150). The alerting scheme, interruption of power transmission, and the like are similar to those in the above-described embodiment with reference to FIG. 4.

Two or more sensors can be used together for more accurate detection of foreign objects. That is, by using a current sensor and a phase sensor together or using a voltage sensor and a phase sensor together to obtain two types of information, it is possible to more accurately detect the presence of foreign substances. 7 shows a configuration of an embodiment using a current sensor and a phase sensor together.

As shown in FIG. 8, the output unit 150 includes a display screen 151, an audio output unit 152, and a warning light 153. The output unit 150 may be used to display charging information, etc. in addition to displaying detection of foreign matter. In addition, in FIG. 7, the output unit 150 includes the display screen 151, the audio output unit 152, and the warning light 153. However, the output unit 150 includes the display screen 151 and the audio output unit. It may be configured to include only at least one of the 152 and the warning light (153).

According to the embodiment of the present invention as described above, when the foreign matter is located around the wireless power transmission device and the charging efficiency is reduced, it can be detected and notified to the user to remove the foreign matter so that the charging can be made normally. In addition, when the charging efficiency falls below a certain limit, the charging is stopped to prevent unnecessary power consumption.

On the other hand, the reason for the mismatch between the wireless power transmitter 100 and the wireless charger 200 is due to the presence of a metallic foreign material as in the above-described example, but around the wireless power transmitter 100 Matching may be incorrect due to a person passing through or changing the position of the charging wireless charger 200.

For example, when a person passes around the wireless power transmitter 100, the matching is temporarily affected by various devices or metallic materials possessed by the person, but again when the person leaves the wireless power transmitter 100. In this case, it is not desirable to indicate an alarm or stop charging.

In addition, when the position of the charging wireless charger changes, such as lifting and lowering the charging device for a while to check the charging state, it is preferable to repeat the matching according to the changed position rather than displaying an alarm.

In consideration of this, in another embodiment of the present invention, when an abnormality in current or voltage is detected during wireless charging, the above-described situation, which is different from the presence of foreign substances, is considered in an appropriate manner.

Meanwhile, in the above-described embodiment, it is determined that the foreign matter exists when the change in voltage, current, and phase exceeds a predetermined value using a voltage sensor, a current sensor, a phase sensor, or the like. However, when the change in voltage or current is measured, the resistance value may be calculated according to Ohm's law, and thus, the presence of the foreign matter may be determined based on the calculated resistance value. In another embodiment of the present invention, the resistance Based on the value, the existence of the foreign matter and the position change of the charging target device are determined.

9 is a flowchart illustrating a foreign material detection method of the wireless power transmission apparatus according to another embodiment of the present invention.

As shown in FIG. 9, first, the resistance value R is detected (S910). The resistance value at this time means a difference between the measured resistance and a reference resistance which is a resistance in a steady state without foreign substances.

If the detected resistance value R is equal to or greater than Rmax, which is a criterion for determining the presence of the foreign matter (YES in S920), as in the other embodiments described above, it is determined that the foreign matter exists and an alarm is output (S930). ). At this time, charging may be suspended as needed.

If the resistance value R is detected but the value is smaller than Rmax (NO in S920), it is considered that the presence of foreign matter is not certain, and the measurement is repeated n times at regular time intervals (S940).

Next, the resistance value R is compared with the reference value Rmin using the result of repeating n measurements (S950). At this time, Rmin is a value smaller than Rmax. When the resistance value R is less than or equal to Rmin, it is determined that the influence of charging is not large even though the resistance is slightly changed, and the charging is continued and the process returns to the initial step (S910) of detecting the resistance value.

On the contrary, when R is greater than Rmin (No in S950), the impedance matching is re-executed by judging that the resistance value is changed due to the movement of the charging target device, but not negligible value, but not due to the presence of foreign matter. (S960). That is, the current power transmission is stopped, the transmitter transmits test power, and the receiver observes the received power level and notifies the transmitter to find the matching value with the highest received power.

On the other hand, various methods can be used to repeat the measurement n times to obtain the resultant resistance value R. For example, the average of the values measured n times can be used, or the maximum value can be used among the results measured n times.

According to the embodiment of the present invention as described above, when the resistance value changes due to the environmental change around the wireless power transmission apparatus, it is possible to infer the appropriate change according to the change in the environment according to the change in the resistance value. That is, when the foreign matter is located and the charging efficiency is reduced, it detects it and informs the user to remove the foreign matter so that the charging is normally performed, and stops charging when the charging efficiency falls below a certain limit, thereby consuming unnecessary power consumption. If the matching is changed due to the movement of the charging target device, the matching is performed again to increase the charging efficiency.

Although the present invention has been described above with reference to preferred embodiments, the apparatus and method of the present invention are not necessarily limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims will include such modifications and variations as long as they fall within the spirit of the invention.

Claims

A wireless power transmission device for transmitting power in a magnetic resonance induction method to an external wireless charger,

An oscillator for generating a signal of a predetermined constant frequency,

A power amplifier for amplifying the signal generated by the oscillator;

A matching network for frequency matching to transmit the signal amplified by the power amplifier in a magnetic resonance induction manner;

A transmission antenna for transmitting a frequency matched signal by the matching network to the wireless charger;

A current sensor connected between the matching network and the transmitting antenna;

If the resistance value according to the difference between the current sensed by the current sensor and the predetermined reference current exceeds a first predetermined threshold, it is determined that the foreign matter exists to control to display the presence of the foreign matter to the user, and the resistance If the value does not exceed the first threshold, the resistance value is redetected two or more times at regular time intervals, and the second and second threshold values, which are predetermined by the redetected resistance value, are smaller than the first threshold value. And a control unit for controlling the matching network to re-perform frequency matching when exceeding.
The method of claim 1, wherein the control unit,

And determining whether the resistance value detected again exceeds the second threshold value, based on an average of the resistance values detected again two or more times.
The method of claim 1, wherein the control unit,

And determining whether the resistance value detected again exceeds the second threshold value, based on a maximum value of the resistance value detected again two or more times.
The method of claim 1,

Wireless power transmission device further comprising a display unit for displaying the presence of the foreign matter to the user.
A wireless power transmission device for transmitting power in a magnetic resonance induction method to an external wireless charger,

An oscillator for generating a signal of a predetermined constant frequency,

A power amplifier for amplifying the signal generated by the oscillator;

A matching network for frequency matching to transmit the signal amplified by the power amplifier in a magnetic resonance induction manner;

A transmission antenna for transmitting a frequency matched signal by the matching network to the wireless charger;

A voltage sensor connected between the matching network and the transmitting antenna;

When the resistance value according to the difference between the voltage sensed by the voltage sensor and the predetermined reference voltage exceeds a first predetermined threshold, it is determined that the foreign matter exists to control to display the presence of the foreign matter to the user, and the resistance If the value does not exceed the first threshold, the resistance value is redetected two or more times at regular time intervals, and the second and second threshold values, which are predetermined by the redetected resistance value, are smaller than the first threshold value. And a control unit for controlling the matching network to re-perform frequency matching when exceeding.
The method of claim 5, wherein the control unit,

And determining whether the resistance value detected again exceeds the second threshold value, based on an average of the resistance values detected again two or more times.
The method of claim 5, wherein the control unit,

And determining whether the resistance value detected again exceeds the second threshold value, based on a maximum value of the resistance value detected again two or more times.
The method of claim 5,

Wireless power transmission device further comprising a display unit for displaying the presence of the foreign matter to the user.