KR102084532B1 - Smart far-field wireless power transfer system and method thereof - Google Patents

Abstract

The present invention relates to an intelligent remote wireless power transmission system and a method therefor, the wireless power transmission apparatus of the present invention is provided with a signal generating unit for generating a power signal, a plurality of antennas, the antenna unit for receiving a plurality of pulse signals , A controller that detects at least one harmonics from the plurality of pulse signals and calculates a delay time for each antenna based on the detected harmonics, modulates the power signal into an RF power signal, and modulates the RF power signal It includes a modulator for time-reversa according to the delay time calculated for each antenna and transmitting through the corresponding antenna.

Description

SMART FAR-FIELD WIRELESS POWER TRANSFER SYSTEM AND METHOD THEREOF

The present invention relates to remote wireless power transmission in a complex radio wave environment in which a plurality of scattering objects and electronic devices are present.

2. Description of the Related Art In recent years, as the use of small and ultra-small wireless devices has increased in fields such as mobile devices, Internet of Things (IoT), sensors, and bio-implantation devices, demands for long-distance wireless power transmission and charging are increasing. However, the existing wireless power transmission technology is largely divided into a short-range method using a magnetic field and a long-distance method using radio waves, and the short-range wireless power transmission transmits power through a magnetic induction method using a coil and a magnetic resonance method using a resonance circuit. The farther away, the sharper the efficiency. On the other hand, long-distance wireless power transmission is capable of transmitting medium- and long-range power by radiating electromagnetic waves through an antenna. Mainly, high-gain antenna and array antenna-based beamforming are used to focus power on a desired point.

However, beamforming is less efficient when there are many obstacles or when a single antenna is used, and in a complex radio wave environment such as an indoor environment, there is a limitation in focusing the radio waves using the conventional long-range wireless power transmission.

Accordingly, there is a need to develop a technology capable of overcoming the limitations of the conventional wireless power transmission technology in a complex radio wave environment in which multiple paths exist and more effectively performing remote wireless power transmission.

Korean Registered Patent No. 10-1641437 (2016.07.20.), Name of invention: Cast-route-based transmission method, and apparatus for performing same

The present invention is an intelligent long-range wireless capable of more effectively detecting and identifying a target device and selectively focusing a radio wave through a time-reversing technique using harmonics in a complex radio wave environment in which a plurality of scattering objects and electronic devices exist. The purpose is to provide a power transmission system and method.

In addition, an object of the present invention is to provide an intelligent long-range wireless power transmission system and a method capable of selectively converging radio waves to a single element even in an environment in which multiple non-linear elements (wireless power receiving devices) exist.

In order to achieve the above object, a wireless power transmission apparatus according to an embodiment of the present invention is provided with a signal generating unit for generating a power signal, a plurality of antennas, an antenna unit for receiving a plurality of pulse signals, the plurality of A control unit that detects at least one harmonic in the pulse signal and calculates a delay time for each antenna based on the detected harmonics, modulates the power signal into an RF power signal, and modulates the RF power signal for each antenna. It includes a modulator for time-reversing and transmitting through the corresponding antenna according to the calculated delay time.

The control unit may detect harmonics using PI (Pulse Inversion).

In addition, the control unit may identify as an electronic device when a harmonic is detected in the pulse signal, as a non-electronic device when only a fundamental wave is detected, and select the identified electronic device as a target device.

In addition, when the sensed harmonics are a plurality of different harmonics, the controller may select one target device based on the eigenvalues of the plurality of harmonics.

In addition, the control unit may calculate a delay time for each antenna using a decomposition of the time-reversal operator (DORT) technique.

In addition, the control unit performs a Fourier transform on the pulse signal received through the plurality of antennas to transform it into frequency domain data, and performs EVD (eigenvalue decomposition) based on the frequency domain data to perform unique A time reversal operator composed of an eigenvalue and an eigenvector is calculated, and a delay time to be applied to each antenna of time inversion can be calculated using the eigenvalue and the eigenvector.

The eigenvalue may include information on a device that has transmitted the corresponding pulse signal, and the eigenvector may include information on the phase and amplitude of the pulse signal.

The delay time can be calculated using the following equation.

[Mathematics]

Here, φ is the phase value of the eigenvector, and f is the frequency.

The antenna unit may be an array antenna or a distributed antenna.

In order to achieve the above object, an intelligent remote wireless power transmission system according to another embodiment of the present invention detects at least one harmonics from a plurality of pulse signals received through a plurality of antennas, and the sensed harmonics Select the target wireless power receiving device based on, calculate the delay time for each antenna, and time-reversal the power signal according to the calculated delay time for each antenna to transmit the wireless power through the corresponding antenna And a wireless power receiving device generating a harmonic and receiving a power signal from the wireless power transmitting device.

The radio power transmission apparatus calculates eigenvalues and eigenvectors respectively by applying a DORT technique to each of the sensed harmonics, selects a target wireless power receiving apparatus based on the eigenvalues, and selects each based on the eigenvectors. Delay time for each antenna can be calculated.

The wireless power receiving device radiates harmonics, an antenna unit that receives a power signal from the wireless power transmission device, generates a harmonic by nonlinear characteristics, and a rectifying unit that rectifies the power signal received through the antenna unit into a DC signal. It can contain.

In order to achieve the above object, the intelligent remote wireless power transmission method according to another embodiment of the present invention, a wireless power transmission device in a complex radio wave environment in which a plurality of scattering objects and electronic devices are present, a wireless power receiving device In the transmission method, Receiving a plurality of pulse signals through a plurality of antennas, detecting at least one harmonic (harmonics) from the plurality of pulse signals, receiving the wireless power based on the detected harmonics Selecting a device, calculating a delay time for each antenna using a decomposition of the time-reversal operator (DORT) technique, modulating a power signal into an RF power signal, and delaying the RF power signal for each antenna And reversing the time according to time to transmit through the corresponding antenna.

According to the present invention, it is possible to more effectively detect and identify the target device and selectively focus the radio wave through a time-reversing technique using harmonics in a complex radio wave environment in which a plurality of scattering objects and electronic elements exist.

In addition, radio waves can be selectively focused on one element even in an environment in which multiple nonlinear elements (wireless power receiving devices) exist.

1 is a view showing an intelligent remote wireless power transmission system according to an embodiment of the present invention.
2 is a view for explaining an intelligent remote wireless power transmission system for selectively transmitting power to one wireless power receiving device in an environment in which a plurality of wireless power receiving devices according to another embodiment of the present invention exist.
3 is a block diagram schematically showing the configuration of a wireless power transmission apparatus according to an embodiment of the present invention.
4 is a block diagram schematically showing a wireless power receiving apparatus according to an embodiment of the present invention.
5 shows an illustration of a 2D model of a complex radio wave environment in which a plurality of scattering objects and electronic devices are present according to an embodiment of the present invention.
FIG. 6 is a graph showing eigenvalues of TRO after background subtraction in FIG. 5 (a).
7 is a view showing a result of focusing simulation associated with the eigenvalue of FIG. 6.
8 is a graph showing eigenvalues of TRO after applying PI (PI-DORT) to FIG. 5 (a).
9 is a view showing a simulation result for FIG.
10 is a graph showing an intrinsic value of TRO after applying PI-DORT to FIG. 5 (b).
11 is a view showing a simulation result for FIG.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be described in detail with reference to the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals are used for similar components.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related description items or any one of a plurality of related description items.

When a component is said to be "connected" to or "connected" to another component, it should be understood that other components may be directly connected to or connected to the other component, but may exist in the middle. something to do. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

The terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof described herein, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Throughout the specification and claims, when a part includes a certain component, this means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an intelligent remote wireless power transmission system according to an embodiment of the present invention.

Referring to FIG. 1, an intelligent remote wireless power transmission system according to an embodiment of the present invention receives wireless power from wireless power transmission apparatus 100 and wireless power transmission apparatus 100 that transmit power wirelessly. It includes a device 200. Such a system transmits power wirelessly based on time-reversal, which is a method of generating harmonics peculiar to electronic devices and a focusing technique.

The wireless power transmission apparatus 100 is provided with a plurality of antennas, detects harmonics from pulse signals received through the plurality of antennas, and selectively applies radio waves by applying a time-reversal technique to the harmonics. Focus. At this time, the wireless power transmission apparatus 100 may detect a harmonic by using a pulse inversion (PI).

The wireless power transmission apparatus 100 may transmit a pulse and detect a harmonic in a pulse signal in response to the pulse, or detect a harmonic in a pulse signal generated by itself in a nonlinear device without transmitting a pulse.

Specifically, when the wireless power transmission apparatus 100 transmits a pulse in a complex radio wave environment in which a plurality of linear and non-linear elements exist, the linear and non-linear elements scatter the response pulse signal for the pulse. Then, the wireless power transmission apparatus 100 receives the scattered response pulse signal and detects harmonics from the response pulse signal. At this time, the wireless power transmission apparatus 100 may detect harmonics using PI, and PI is a method of detecting even-order harmonics 2f ₀ by suppressing scattering in fundamental and odd-order harmonics. That is, PI solves the overlap problem between the fundamental and harmonic responses as well as the limited receiver dynamic range due to the significantly weaker harmonic response compared to the fundamental band, and in the case of multi-static systems, the coupling between elements can be completely eliminated. Since PI suppresses fundamental and odd harmonics, coupling between elements can be essentially eliminated.

Hereinafter, the PI technique will be described.

PI can be performed using two transmit pulses of different polarities ((p (t) and n (t), n (t) =-p (t)).) The response of is inverted such that its linear combination is “0.” In addition, in the case of a nonlinear target, harmonic generation can be expressed by a power expansion as shown in Equation 1 described below.

[Equation 1]

)는 양성 기본 주파수(positive fundamental frequency) 성분과 고조파 성분으로 구성될 수 있고, 음성 송신 펄스(-(p(t))를 송신 시, 응답 펄스신호(

)는 음성 기본 주파수(negative fundamental frequency) 성분과 고조파 성분으로 구성될 수 있다.That is, when transmitting a positive transmission pulse ((p (t)), a response pulse signal (

) May be composed of a positive fundamental frequency component and a harmonic component, and when transmitting a negative transmission pulse (-(p (t)), a response pulse signal (

) May be composed of a negative fundamental frequency component and a harmonic component.

와

의 선형 조합(linear combination)은 기본파와 홀수 차 고조파를 제거하고, 2차 고조파를 두배가 되도록 한다. 즉, 두개의 응답 신호를 더하면 기본 주파수 성분은 극성이 반대이기 때문에 서로 상쇄되어 신호를 형성하지 않고, 고조파 주파수 성분은 아래 수학식 2와 같이 그 크기가 두 배가 될 수 있다.

Wow

The linear combination of removes the fundamental and odd-order harmonics, and doubles the second-order harmonics. That is, if two response signals are added, since the fundamental frequency components have opposite polarities, they do not cancel each other to form a signal, and the harmonic frequency components may double in size as shown in Equation 2 below.

[Equation 2]

In environments where linear and nonlinear targets are present, PI suppresses the fundamental frequency components, and since linear targets do not produce harmonics, PI can completely suppress linear clutter.

As described above, in the PI technique, the linear target does not cancel the positive pulse signal and the negative pulse signal to form a signal, and the nonlinear target does not cancel each other, thereby amplifying a large signal. Accordingly, the wireless power transmission device 100 identifies as an electronic device when a harmonic is detected in a pulse signal received from the wireless power receiving device 200, identifies as a non-electronic device when only a fundamental wave is detected, and identifies The electronic device may be identified as a target wireless power receiving device 200.

In addition, the wireless power transmission apparatus 100 may not transmit a pulse, but the wireless power reception apparatus 200 may receive a pulse signal including harmonics generated by itself. In this case, the wireless power transmission apparatus 100 may detect harmonics from the received pulse signal.

As described above, when a harmonic is detected from a pulse signal received by the wireless power transmission apparatus 100 through a plurality of antennas, a time inversion technique is applied to the harmonic to transmit a power signal. Here, the time reversal technique is a technique of increasing focusing efficiency, such as a radio wave focusing technique. That is, in the time-reverse electrical method, the N array antennas of the wireless power transmission apparatus 100 receive the pulse signal transmitted from the wireless power reception apparatus 200, calculate the delay time of the received signal, and calculate the calculated delay time. It is a technique that enables energy focusing by transmitting power signals by applying to each antenna element. The time reversal technique includes a time reversal mirrors technique, a Decomposition of Time-Reversal Operator (DORT) technique, and preferably a DORT technique.

The Decomposition of Time-Reversal Operator (DORT) technique uses an antenna array (transducer) to selectively focus radio waves on an arbitrary scatterer in an environment that includes multiple scatterers. TR-based processing technology that uses multiple static responses received. DORT implements eigenvalue decomposition (EVD) for frequency domain multi-static data and its conjugate complex number (equivalent to the frequency domain of time reversal), and a set of eigenvalues representing the scatterers detected in the environment. Eigenvectors representing paths from scatterers are generated. The eigenvector can be used to calculate the delay time to apply time reversal to each of the array antennas, and to delay the delay time as much as the delay time to transmit the power signal, thereby selectively focusing the target device.

Hereinafter, the DORT will be described in detail.

)로 표현되며, 시간 역전 연산자(TRO, time-reversal operator)(

)는

로 정의된다.DORT uses an N-element array antenna in which time-domain responses are received in all monostatic and bistatic combinations. The DORT process starts by arranging the received time domain data in an NxN multi-matrix (K (t)), and each column of K (t) represents the response received when the antenna of that column is transmitting. The frequency domain data (K (ω)) is obtained by Fourier transforming the time domain data K (t), and the time reversal in the frequency domain is Hermitian transpose (

), And the time-reversal operator (TRO)

) Is

Is defined as

와 V의 고유값과 고유벡터는 아래 수학식 3과 같은 관계로 나타낼 수 있게 된다.TRO is dependent on eigenvalue. Since the ideal TRO has a Hermitian matrix, the TRO consists of diagonal matrices, and can be represented by eigenvectors and eigenvalues. According to Hermitian operators' theory, if the λ values of the eigenvalues have a real value and the eigenvectors have an orthogonal value

The eigenvalues and eigenvectors of and V can be expressed by the following equation (3).

[Equation 3]

Relatively large eigenvalues are the same as the number of scattering signals (pulse signals) transmitted by the scattering objects, and the corresponding eigenvector has time and phase reversal because it has information necessary for focusing the scattering signals of each array antenna. In the DORT technique, the values of eigenvetor and eigenvalue are selected as important factors. To obtain eigenvalue and eigenvector of TRO calculated by this process, SVD (singular value decomposition) defined as Equation 4 described below is used.

[Equation 4]

Here, S represents a diagonal matrix of singular values.

가 수학식 2와 같이 정의되면, 시간역전 연산자(

)는 아래 기재된 수학식 5와 같을 수 있다. K (ω) and

If is defined as Equation 2, the time inversion operator (

) May be the same as Equation 5 described below.

[Equation 5]

는 대각 행렬의 실수 값을 나타내며 각 고유값은 그 환경에서 각각 검출된 산란물체(scatterer)와 일치한다.

와

은 각 타겟으로의 순방향 전파와 역방향 전파를 기술하는 고유 벡터를 나타낸다. 고유 벡터 행렬 (

)은

와 같은 각 안테나에 대해 위상 변이와 함께 주어진 주파수(ω_f)를 중심으로 하는 변조된 가우시안 펄스를 생성하는데 사용된다. 각각의 안테나에서 송신된 펄스는 선택된 타겟에 집속 펄스를 발생시킨다. here,

Denotes the real value of the diagonal matrix, and each eigenvalue coincides with the scatterer detected in the environment.

Wow

Denotes an eigenvector describing forward and reverse propagation to each target. Eigenvector matrix (

)silver

It is used to generate a modulated Gaussian pulse centered on a given frequency (ω _f ) with a phase shift for each antenna such as. The pulse transmitted from each antenna generates a focused pulse at the selected target.

When the eigenvalues and eigenvectors are calculated through the SVD process, time delay can be calculated using the calculated eigenvalues and eigenvectors. That is, since the eigenvalue includes information on the device that transmitted the corresponding pulse signal, and the eigenvector contains information on the phase and amplitude of the corresponding pulse signal, each antenna of time inversion using Equation 6 described below The delay time (Δt (x)) to be applied to can be calculated.

[Equation 6]

Here, φ is the phase value of the eigenvetor and f is the frequency.

As described above, the wireless power transmitter detects harmonics using PI (pulse reversal), and applies a DORT (time reversal operator decomposition) technique to calculate the delay time to be applied to each antenna in time reversal. Then, the wireless power transmission apparatus 100 modulates the power signal into an RF power signal, time-reversa the RF power signal according to the calculated delay time for each antenna, and transmits it through the corresponding antenna.

The wireless power receiving device 200 generates harmonics. At this time, the wireless power receiving device 200 generates a harmonic in response to the pulse when a pulse is received from the wireless power transmitting device 100, or even if a pulse is not received from the wireless power transmitting device 100, the harmonic itself Can cause

The wireless power receiving device 200 includes a non-linear element such as a rectifying element, and the non-linear element generates harmonics through non-linear interaction. That is, the harmonics are generated due to the non-linear interaction of the electronic device made of a semiconductor, which means that when a fundamental wave of frequency f _o is transmitted, a frequency of 2f _o , 3f _o ... By using the harmonics peculiar to these electronic devices, it is possible to detect a very small electronic device having a small scattering area.

In addition, the wireless power receiving device 200 converts the RF power signal received from the wireless power transmitting device 100 into DC power.

In the intelligent long-range wireless power transmission system configured as described above, the wireless power transmission apparatus 100 detects and classifies harmonics when a non-linear element is present, even if the target object is a passive object, and applies time reversal to target in a complex radio wave environment. It is possible to effectively focus the radio waves at the branch. That is, the wireless power transmission apparatus 100 may detect harmonics generated from the nonlinear elements of the wireless power reception apparatus 100 by using a pulse inversion (PI). Then, when the power signal is time-reversed and transmitted based on the sensed harmonics, the wireless power transmission apparatus 100 focuses on spatio-temporal radio waves reaching the receiving point in an instant due to invalidation of the time delay generated in the multipath. The phenomenon occurs. Therefore, it is possible to selectively focus the radio waves to various reception locations in a multipath radio wave environment.

On the other hand, the present invention is a system applied to a complex radio wave environment in which a plurality of linear and non-linear elements are present. In FIG. 1, one wireless power receiving device 200 is illustrated, but a plurality of linear devices other than the wireless power receiving device 200 are shown. Devices may be present.

In addition, the present invention is applicable to a complex radio wave environment in which a plurality of linear elements as well as a plurality of non-linear elements (for example, a plurality of wireless power receiving devices) exist. When a plurality of linear elements and a plurality of wireless power receiving devices exist, a method of selecting a target wireless power receiving device and selectively focusing radio waves will be described in FIG. 2.

2 is a view for explaining an intelligent remote wireless power transmission system according to another embodiment of the present invention.

Referring to Figure 2, the intelligent remote wireless power transmission system according to another embodiment of the wireless power transmission apparatus 100 for transmitting power wirelessly, a plurality of wireless power receiving apparatus (200a, 200b, .., 200n, less than 200 This is called).

The plurality of wireless power receiving devices 200 generate harmonics having different frequencies, and the wireless power transmitting device 100 receives pulse signals including harmonics from the plurality of wireless power receiving devices 200. At this time, the plurality of wireless power receiving apparatus 200 generates a harmonic in response to the pulse when a pulse is received from the wireless power transmitting apparatus 100, or even if a pulse is not received from the wireless power transmitting apparatus 100 Can cause harmonics.

When a pulse signal is received, the wireless power transmitter 100 detects a plurality of harmonics using a PI (pulse reversal) and applies a DORT technique to the sensed plurality of harmonics, so that among the plurality of wireless power receivers 200 One is selected as the target device, and the power signal is time-inverted and transmitted to the selected target device. That is, the wireless power transmission apparatus 100 applies the SVD to each pulse signal to calculate the eigenvalue and the eigenvector, respectively, selects a target wireless power receiving apparatus based on the calculated eigenvalue, and based on the eigenvector Time signal can be reversed.

For example, if there is a wireless power receiving device 1 (200a), a wireless power receiving device 2 (200b), a wireless power receiving device 3 (200c), a wireless power receiving device 4 (200d), the wireless power transmitting device 100 Eigenvalues and eigenvectors for pulse signals transmitted from each of the wireless power receiving device 1 (200a), the wireless power receiving device 2 (200b), the wireless power receiving device 3 (200c), and the wireless power receiving device 4 (200d). Each is calculated, and based on the calculated eigenvalue, the wireless power receiving device 2 (200b) may be selected as a target device, and the power signal may be time-reversed and transmitted to the wireless power receiving device 2 (200b).

As described above, the wireless power transmitter 200 may selectively focus radio waves on one non-linear element even in an environment in which multiple non-linear elements (wireless power receivers) exist through the DORT technique.

The detailed description of the wireless power transmission apparatus 100 will be referred to FIG. 3, and the detailed description of the wireless power transmission apparatus 200 will be referred to FIG. 4.

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

Referring to FIG. 3, the wireless power transmission apparatus 100 according to an embodiment of the present invention includes a signal generator 110, a controller 120, a modulator 130, and an antenna 140.

The signal generator 110 may generate a power signal. For example, the power signal may be an AC signal having a constant amplitude and phase. The signal generator 110 may transmit the power signal to the modulator 130. The power signal can transmit electromagnetic waves in various frequency ranges. For example, the power signal may be an electromagnetic file including a radio frequency or a microwave frequency range. Radio frequency or short wavelength can reduce interference to other communication devices. For example, frequencies in the Industrial Scientific Medical (ISM) band region can be used.

The controller 120 detects harmonics from a plurality of pulse signals received through each antenna of the antenna unit 140 and calculates a delay time for each antenna based on the detected harmonics. At this time, the control unit 120 may transmit a pulse, detect a harmonic in a pulse signal in response to the pulse, or detect a harmonic in a pulse signal generated by itself in a nonlinear device without transmitting a pulse.

Hereinafter, the operation of the control unit 120 will be described in more detail.

First, the control unit 120 detects harmonics from the pulse signal received through the antenna unit 140. At this time, the controller 120 may detect a harmonic using PI, and the detected harmonic may be a second harmonic (2f _o ). That is, since the wireless power transmission device 100 and the wireless power receiving device is a complex radio wave environment with an obstacle in the propagation path, and the wireless power receiving device includes a non-linear element such as a rectifying element, the non-linear element of the wireless power receiving device is Nonlinear interactions create harmonics. Accordingly, the pulse signal transmitted by the wireless power receiving device reaches through multiple paths, thereby generating a time-dispersed pulse signal, and the controller 120 uses the time-dispersed pulse signal in the non-linear element of the wireless power receiving device. Harmonics can be detected.

In addition, the controller 120 identifies as an electronic device when a harmonic is detected in a pulse signal received from the wireless power receiving device, identifies as a non-electronic device when only a fundamental wave is detected, and targets the identified electronic device as a target. ) Can be identified by the device.

Through this, the wireless power transmission apparatus 100 can selectively detect and transmit various types of harmonics as well as detecting harmonics in a radio wave environment in which multiple scattering objects and electronic devices exist.

When a harmonic is detected using PI, the controller 120 applies a DORT technique to the detected harmonic to calculate a delay time to be applied to each antenna in time reversal. That is, the controller 120 performs Fourier transform on a pulse signal received through a plurality of antennas to convert it into frequency domain data, and performs EVD (eigenvalue decomposition) based on the frequency domain data to perform unique A time reversal operator composed of an eigenvalue and an eigenvector is calculated, and a delay time to be applied to each antenna of the time inversion is calculated using the eigenvalue and the eigenvector. Since the eigenvalue includes information on the device that transmitted the corresponding pulse signal, and the eigenvector contains information on the phase and amplitude of the corresponding pulse signal, the controller 120 uses Equation (6) to determine each time shift. The time delay to be applied to the antenna can be calculated. 1 for a detailed description of the DORT technique.

In addition, when a plurality of different harmonics are detected, the controller 120 applies a DORT technique to the detected plurality of harmonics, selects one of the plurality of wireless power receiving devices as a target device, and transmits a power signal to the selected target device. Transmit time and transmit. That is, the controller 120 calculates the eigenvalue and the eigenvector by applying SVD to each pulse signal received from a plurality of wireless power receivers, and selects a target wireless power receiver based on the calculated eigenvalues, The power signal can be reversed based on the eigenvector.

In addition, the controller 120 may control the overall operation of the wireless power transmission apparatus 100. The controller 120 may provide a phase amplitude control algorithm to be performed by the modulator. The controller 120 may calculate phase modulation and amplitude modulation of the power signal so that the wireless power transmission efficiency is high. For example, the controller 120 may calculate phase modulation and amplitude modulation based on the sensed harmonics and provide them to the modulation unit.

The control unit 120 may be formed of a microprocessor or various analog-digital logics.

The modulator 130 modulates the power signal generated by the signal generator 110 into an RF power signal, and time-reversa the RF power signal according to the calculated delay time for each antenna to transmit through the corresponding antenna do. That is, the modulator 130 converts the AC power signal generated by the signal generator 110 to DC to the RF power signal, and delays the converted RF power signal by a delay time calculated for each antenna. Then, transmit through the corresponding antenna.

Meanwhile, since the delay time is calculated in phase and frequency as shown in Equation 6, the modulator 130 can time-reversa the phase of the RF power signal and amplify the amplitude. That is, the modulator 130 may modulate the power signal PS received from the signal generator 110 to have a phase-inverted phase of the harmonic sensed under the control of the controller 120. For example, the reverse phase can be obtained by complex conjugate the wave. For example, the reverse phase can be obtained by inverting the phase of the wave by π / 2. In addition, the modulator 130 may amplify the amplitude of the power signal under the control of the controller 120. In the case of transmission of a modulated power signal having a reverse phase, the amplitude of the harmonics is related to the efficiency of power transmission. Since the amount of transmittable power of the wireless power transmission apparatus 100 is limited, a phase amplitude control algorithm for efficient power transmission may be required. For example, the phase amplitude control algorithm may control the amplitude amplification factor of the power signal by referring to the amplitude of the harmonics. For example, the phase amplitude control algorithm may assign a weight value calculated by the control unit to transmit a power signal having a larger amplitude when the harmonic amplitude is large. The modulator 130 modulates the power signal by receiving the phase amplitude control algorithm from the control unit 120.

The antenna unit 140 receives a pulse signal from the wireless power receiving device, and transmits the modulated power signal from the modulating unit 130 to the wireless power receiving device. Here, the antenna unit 140 is an antenna in a form of obtaining a high gain by arranging a plurality of antennas at an appropriate location so that the energy radiated in a specific direction increases, and may be, for example, an array antenna.

The antenna unit 140 may include a plurality of antennas, and the plurality of antennas may be connected one-to-one or many-to-one with the modulator 130.

The wireless power transmission apparatus 100 configured as described above senses harmonics and time-reverses the power signals generated by the signal generator 110 based on the harmonics, and transmits them through the antenna unit 140. Then, due to the invalidation of the time delay generated in the multipath, a spatio-temporal propagation phenomenon occurs that reaches the receiving point in an instant. That is, the wireless power transmission apparatus 100 may selectively focus radio waves to various reception locations in a multi-path radio wave environment.

4 is a block diagram schematically showing a wireless power receiving apparatus according to an embodiment of the present invention.

4, the wireless power receiving apparatus 200 according to an embodiment of the present invention includes an antenna 210, a rectifying unit 220, a control unit 230.

The antenna 210 may include a single or multiple antennas. For example, the antenna 210 may include at least one multi-polarized antenna.

The rectifying unit 220 may rectify the power signal transmitted as an RF signal into a DC signal. The DC signal, which is a rectified power signal, can be directly supplied to the operation of the wireless power receiving device 200 itself. For example, the DC signal may be supplied to the control unit 230. Alternatively, the DC signal may be supplied to the battery unit BT shown by a dotted line. For example, the battery unit BT may be charged by a DC signal and supply power to the wireless power receiving device. For example, after the battery unit BT is fully charged by the DC signal, the battery unit BT may transmit a signal indicating that the controller 230 is fully charged.

In addition, the rectifying element included in the rectifying unit 220 is connected to the antenna 210 to convert the received signal into electric power, but generates harmonics due to nonlinear characteristics. Therefore, the antenna 210 emits a harmonic signal corresponding to the multiplication frequency of the reception frequency.

The controller 230 may process various information such as battery (not shown) information of the wireless power receiving apparatus 200 and the size of the received power, and control components. For example, the control unit 230 may control the rectifying unit 220.

5 shows an illustration of a 2D model of a complex radio wave environment in which a plurality of scattering objects and electronic devices are present according to an embodiment of the present invention.

FIG. 5 (a) shows a case in which a wireless power transmission apparatus equipped with an array antenna transmits power wirelessly in a radio wave environment in which linear and non-linear elements are present. Referring to (a), the linear element and the nonlinear element generate pulse signals, respectively. Then, the wireless power transmission apparatus receives each pulse signal, and selects a nonlinear element for which harmonics are detected from the pulse signal as a target. At this time, the pulse signal received from the linear element includes only the fundamental wave, and the pulse signal received from the nonlinear element includes harmonic. Therefore, the wireless power transmission apparatus selects a nonlinear element for which harmonics are detected as a target, and transmits the power signal in time-reversed based on the detected second harmonic (2f _o ). Then, the power signal can be focused on the nonlinear device.

FIG. 5 (b) is a diagram illustrating a case in which a radio power transmission apparatus equipped with an array antenna transmits power wirelessly in a radio wave environment in which two nonlinear elements are present. In this case, the nonlinear element generates a pulse signal including harmonics, and the wireless power transmitter detects harmonics from the two pulse signals, respectively. At this time, since each nonlinear element has transmitted harmonics at different frequencies f _o , the wireless power transmission apparatus can select a desired nonlinear element as a target based on the second harmonic 2f _o . Then, the wireless power transmission apparatus transmits the power signal in time-reversed based on the second harmonic (2f _o ) of the nonlinear device selected as the target. Then, the power signal can be focused on the nonlinear device selected as the target.

FIG. 6 is a graph showing eigenvalues of TRO after background subtraction in FIG. 5 (a), and FIG. 7 is a view showing results of focus simulation associated with eigenvalues of FIG. 6.

6, an important eigenvalue is obtained, one representing a nonlinear scatterer and the other a linear scatterer. It can be seen that only one eigenvalue λ1 appears to have significant amplitude in the harmonic band. The eigenvectors associated with λ1 and λ2 at the fundamental center frequency (1.25 GHz) are used to generate a modulated Gaussian pulse that supplies the array. Two separate focus simulations were run for λ1 and λ2, the results of which are shown in FIG. 7 respectively. Referring to (a) of FIG. 7, λ1 has a significant amplitude in a harmonic band, but a wave generated based on λ1 focuses on a linear target, and a wave generated based on λ2 is focused on a nonlinear target, and eigenvalue Is mixed.

One possible explanation is that the eigenvalues are obtained according to the strongest scatterer at each frequency point, because the EVD is performed at each single frequency point without EVD information at different frequencies. That is, the strongest scatterer in the fundamental frequency band is linear scattering and therefore appears at the first eigenvalue. However, at the harmonic frequency, nonlinear scattering is the strongest scatterer, so it appears at the first eigenvalue.

8 is a graph showing the eigenvalue of TRO after applying PI (PI-DORT) to FIG. 5 (a), and FIG. 9 is a diagram showing the simulation results for FIG. 8.

Referring to FIG. 8, since the unique and dominant eigenvalues are in the even-order harmonic band, fundamental and odd-order harmonics are minimized, background subtraction is unnecessary, and mixing of eigenvalues is eliminated. 9 shows the focus at a nonlinear target used to generate a Gaussian pulse in which the eigenvector associated with λ1 at the second harmonic frequency (2.5 GHz) is modulated to supply the array. Focusing occurs on a nonlinear target.

10 is a graph showing the intrinsic value of TRO after applying PI-DORT to FIG. 5 (b), and FIG. 11 is a diagram showing the simulation results for FIG. 10.

Referring to FIG. 10, the fundamental and odd harmonics are removed, but since there are two nonlinear targets, two important eigenvalues appear in the even harmonic band. Focusing simulation was performed based on the eigenvectors for λ1 and λ2, and the results are as shown in FIG. 11. The simulation shows that the propagation is focused at each nonlinear element.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: wireless power transmission device 110: signal generating unit
120, 230: control unit 130: modulation unit
140: antenna unit 200: wireless power receiving device
210: antenna 220: rectifier

Claims (13)

A signal generator for generating a power signal;
An antenna unit provided with a plurality of antennas to receive a plurality of pulse signals;
A control unit for detecting at least one harmonics generated by nonlinear interaction of a nonlinear element from the plurality of pulse signals and calculating a delay time for each antenna based on the detected harmonics; And
A modulator that modulates the power signal into an RF power signal and time-reversa the RF power signal according to a delay time calculated for each antenna to transmit through the corresponding antenna;
Including, wireless power transmission device. According to claim 1,
The control unit,
A wireless power transmission device, characterized in that it detects harmonics using PI (Pulse Inversion). According to claim 2,
The control unit,
When the harmonics are detected in the pulse signal, it is identified as an electronic device, when only the fundamental wave is detected, it is identified as a non-electronic device, and characterized in that the selected electronic device is selected as a target device, wireless power Transmission device. ◈ Claim 4 was abandoned when payment of the set registration fee was made.◈ According to claim 3,
The control unit,
When the detected harmonics are a plurality of different harmonics, a wireless power transmission device, characterized in that for selecting a target device based on the eigenvalues of the plurality of harmonics. According to claim 1,
The control unit,
Wireless power transmission device, characterized in that for calculating the delay time for each antenna using the DORT (decomposition of the time-reversal operator) technique. ◈ Claim 6 was abandoned when payment of the registration fee was set.◈ The method of claim 5,
The control unit,
A Fourier transform is performed on the pulse signal received through the plurality of antennas to convert it into frequency domain data, and eigenvalue and eigenvalue are performed by performing eigenvalue decomposition (EVD) based on the frequency domain data. Wireless power transmission device, characterized in that for calculating the time reversal operator (eigenvector) consisting of, and using the eigenvalue and eigenvector to calculate the delay time to be applied to each antenna of the time inversion. ◈ Claim 7 was abandoned when payment of the set registration fee was made.◈ The method of claim 6,
The eigenvalue includes information on a device that transmits the pulse signal, and the eigenvector includes information on a phase and amplitude of the pulse signal. ◈ Claim 8 was abandoned when payment of the set registration fee was made.◈ The method of claim 7,
The delay time (

) Is a wireless power transmission device, characterized in that calculated using the equation described below
[Mathematics]

Here, φ is the phase value of the eigenvector, and f is the frequency. According to claim 1,
The antenna unit,
Wireless power transmission device, characterized in that the array antenna or distributed antenna. Detects at least one harmonics from a plurality of pulse signals received through a plurality of antennas, selects a target wireless power receiving device based on the detected harmonics, calculates a delay time for each antenna, and calculates a power signal Wireless power transmission device for transmitting through the antenna by time-reversa (time-reversa) according to the calculated delay time for each antenna; And
At least one wireless power receiver that generates the at least one harmonic through nonlinear interaction of a nonlinear element and receives a power signal from the wireless power transmitter;
Including, intelligent remote wireless power transmission system. The method of claim 10,
The wireless power transmission device,
A DORT technique is applied to each of the detected harmonics to calculate eigenvalues and eigenvectors respectively, a target wireless power receiving device is selected based on the eigenvalues, and a delay time for each antenna is calculated based on the eigenvectors Characterized in that, the intelligent remote wireless power transmission system. The method of claim 10,
The wireless power receiving device,
An antenna unit that radiates harmonics and receives a power signal from the wireless power transmitter; And
An intelligent long-range wireless power transmission system comprising a rectifying unit that generates harmonics by a nonlinear characteristic and rectifies a power signal received through an antenna unit into a DC signal. In a complex radio wave environment in which a plurality of scattering objects and electronic devices are present, in a method of transmitting a power signal to a wireless power receiving device by a wireless power transmitting device,
Receiving a plurality of pulse signals generated through non-linear interaction of non-linear elements constituting the wireless power receiving device through a plurality of antennas;
Detecting at least one harmonics from the plurality of pulse signals;
Selecting the wireless power receiving device based on the sensed harmonics, and calculating a delay time for each antenna using a decomposition of the time-reversal operator (DORT) technique; And
Modulating a power signal into an RF power signal, and reversing the RF power signal according to a delay time calculated for each antenna to transmit the signal through the corresponding antenna;
Including, intelligent long-range wireless power transmission method.

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