KR20190129270A - Apparatus and method for wireless power transfer - Google Patents

Abstract

Disclosed are wireless power transfer apparatus and method. According to an embodiment of the present invention, a two-dimensional wireless power transfer apparatus for transferring power to a receiver coil by means of a plurality of transmitter coils including a first transmitter coil on an α axis and a second transmitter coil on a β axis comprises: an estimating unit configured to estimate mutual inductance angles between the plurality of transmitter coils and the receiver coil based on respective currents and voltages of the first transmitter coil and the second transmitter coil; a converting unit configured to demodulate the respective currents of the first and second transmitter coils and convert the demodulated currents into a d-axis current and a q-axis current using the mutual inductance angles; a voltage command generating unit configured to generate an α-axis voltage command and a β-axis voltage command for maximum power transfer based on a d-axis current command, a q-axis current command, the d-axis current, the q-axis current, and the mutual inductance angles; and a power converting unit configured to supply a high-frequency voltage to each of the first and second transmitter coils based on the α-axis voltage command and the β-axis voltage command.

Description

Wireless power transmission apparatus and method {APPARATUS AND METHOD FOR WIRELESS POWER TRANSFER}

Embodiments of the present invention relate to wireless power transmission apparatus and method technology.

Wireless Power Transfer (WPT) technology can be used for wireless charging of small electronic devices such as smart watches and hearing aids. Wireless power transfer and charging devices using the same are increasingly being used as a means of supplying power to mobile electronic devices.

However, the existing wireless power transmission and the charging device using the same has a problem that the power transmission efficiency is changed according to the position of the receiving end.

Korean Patent Publication No. 10-2013-0032472 (published Apr. 2013)

Embodiments of the present invention provide a wireless power transmission apparatus and method.

Two-dimensional wireless power for transmitting power to a receiving coil using a plurality of transmitting coils comprising a first transmitting coil disposed on the α axis and a second transmitting coil disposed on the β axis according to an embodiment of the present invention. The transmitting device includes an estimator for estimating mutual inductance angles between the plurality of transmitting coils and the receiving coils based on currents and voltages of the first transmitting coils and the second transmitting coils, the first transmitting coils, and the A converting unit for demodulating the current of each of the second transmitting coils and converting each of the demodulated currents into a d-axis current and a q-axis current using the mutual inductance angle, a d-axis current command, a q-axis current command, and the d-axis A voltage command generator for generating an α-axis voltage command and a β-axis voltage command for maximum power transfer based on the current, the q-axis current, and the mutual inductance angle, and the α-axis voltage command and the β-axis voltage And a power converter configured to supply a high frequency voltage to each of the first transmitting coil and the second transmitting coil based on a command.

The converting unit demodulates the α-axis current of the first transmission coil and the β-axis current of the second transmission coil, respectively, and a demodulation unit for detecting an envelope for each of the α-axis current and the β-axis current and the mutual inductance. Based on the angle, it may include a dq converter for converting the envelope of the α-axis current and the envelope of the β-axis current to the d-axis current and the q-axis current, respectively.

The voltage command generation unit includes a proportional integral controller and a mutual inductance angle for generating a d-axis voltage command and a q-axis voltage command using the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current. The dq inverse converting unit converts the d-axis voltage command and the q-axis voltage command into the α-axis voltage command and the β-axis voltage command, respectively.

The power converter is configured to control the magnitude of the α-axis voltage and the β-axis voltage applied to the first transmission coil and the second transmission coil based on the α-axis voltage command and the β-axis voltage command. And a resonant inverter configured to generate the high frequency voltage by modulating the α-axis voltage and the β-axis voltage having a controlled size.

Two-dimensional wireless power for transmitting power to a receiving coil using a plurality of transmitting coils comprising a first transmitting coil disposed on the α axis and a second transmitting coil disposed on the β axis according to an embodiment of the present invention. The transmitting method may include estimating mutual inductance angles between the plurality of transmitting coils and the receiving coils based on currents and voltages of the first transmitting coils and the second transmitting coils, respectively. Demodulating the current of each of the two transmitting coils and converting each of the demodulated currents into a d-axis current and a q-axis current using the mutual inductance angle, a d-axis current command, a q-axis current command, the d-axis current, Generating an α-axis voltage command and a β-axis voltage command for maximum power transfer and based on the α-axis voltage command and the β-axis voltage command based on the q-axis current and the mutual inductance angle And a step of supplying high frequency voltage to the first transmission coil group and the second transmission coil, respectively.

The converting may include demodulating the α-axis current of the first transmission coil and the β-axis current of the second transmission coil, respectively, and detecting an envelope for each of the α-axis current and the β-axis current. And converting the envelope of the α-axis current and the envelope of the β-axis current into the d-axis current and the q-axis current, respectively, based on an inductance angle.

The generating may include generating a d-axis voltage command and a q-axis voltage command using the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current, and based on the mutual inductance angle. The method may include converting the d-axis voltage command and the q-axis voltage command into the α-axis voltage command and the β-axis voltage command, respectively.

The supplying may include controlling the magnitudes of the α-axis voltage and the β-axis voltage applied to the first transmission coil and the second transmission coil, respectively, based on the α-axis voltage command and the β-axis voltage command; And generating the high frequency voltage by modulating the amplitude-controlled α-axis voltage and the β-axis voltage.

According to embodiments of the present invention, a mutual inductance angle between a plurality of transmitting coils and a receiving coil is estimated, and a voltage command is calculated based on the estimated mutual inductance angle and a current command to supply a high frequency voltage to the plurality of transmitting coils. As a result, even when the location of the receiver is changed, the maximum power can be transmitted to improve the efficiency of wireless power transmission.

1 is a diagram illustrating an example of an equivalent circuit of a wireless power transmission system using resonance inductive coupling according to an embodiment of the present invention.
2 is a block diagram of a wireless power transmission apparatus according to an embodiment of the present invention
3 is a flow chart of a wireless power transmission method according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to assist in a comprehensive understanding of the methods, devices, and / or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification. The terminology used in the description is for the purpose of describing embodiments of the invention only and should not be limiting. Unless expressly used otherwise, the singular forms “a,” “an,” and “the” include plural forms of meaning. In this description, expressions such as "comprises" or "equipment" are intended to indicate certain features, numbers, steps, actions, elements, portions or combinations thereof, and one or more than those described. It should not be construed to exclude the presence or possibility of other features, numbers, steps, actions, elements, portions or combinations thereof.

1 is a diagram illustrating an example of an equivalent circuit of a wireless power transmission system using resonance inductive coupling according to an embodiment of the present invention.

The wireless power transmission system is a two-dimensional wireless power transmission system that transmits power to a receiving coil using a plurality of transmission coils including a first transmission coil disposed on the α axis and a second transmission coil disposed on the β axis. .

In detail, the wireless power transmission system wirelessly transmits power from a transmitter to a receiver by using resonance inductive coupling between two transmitting coils, that is, a first transmitting coil and a second transmitting coil, and one receiving coil. In this case, the transmitting coil and the receiving coil may be formed in a circular shape.

Referring to FIG. 1, an equivalent circuit of a wireless power transmission system using resonance inductive coupling includes a transmitter and a receiver.

) 및 커패시턴스(

)를 포함한다. 또한, 제1 송신 코일 및 제2 송신 코일은 각각

및

값을 가지는 인덕턴스를 포함한다. 제1 송신 코일 및 제2 송신 코일의 입력단자에는 각각 전류(

,

) 및 전압(

,

)이 인가된다. 이때, 제1 송신 코일의 전류와 제2 송신 코일의 전류의 합성벡터는

로 나타내고, 제1 송신 코일의 전류 벡터와 합성 벡터가 이루는 각도는

로 나타낸다. 또한, 제1 송신 코일과 제2 송신 코일이 서로 직교(orthogonal)하는 것으로 가정하면, 제1 송신 코일과 제2 송신 코일 사이의 상호 인덕턴스(

) 값은 0이다.The transmitting end includes a first transmitting coil disposed on the α axis and a second transmitting coil disposed on the β axis. In this case, the first transmission coil and the second transmission coil are resistors (

) And capacitance (

). Further, the first transmitting coil and the second transmitting coil are respectively

And

Contains an inductance with a value. The input terminals of the first transmitting coil and the second transmitting coil each have a current (

,

) And voltage (

,

) Is applied. In this case, the composite vector of the current of the first transmission coil and the current of the second transmission coil is

The angle formed by the current vector and the composite vector of the first transmission coil is

Represented by Further, assuming that the first transmitting coil and the second transmitting coil are orthogonal to each other, mutual inductance between the first transmitting coil and the second transmitting coil (

) Value is 0.

)을 포함한다. 또한, 수신 코일은 저항(

), 커패시턴스(

) 및 인덕턴스(

)를 포함한다.On the other hand, the receiving end is the resistance of the receiving coil and the receiving end (

). In addition, the receiving coil has a resistance (

), Capacitance (

) And inductance (

).

,

이라고 가정하면, 무선전력전송 시스템의 전력 전송 효율은 아래 수학식 1을 이용하여 산출할 수 있다.At this time,

,

In this case, the power transmission efficiency of the wireless power transmission system may be calculated using Equation 1 below.

는 전력 전송 효율,

은 출력 전력,

는 입력 전력,

는 제1 송신 코일의 소모 전력,

는 제2 송신 코일의 소모 전력,

는 수신 코일의 소모 전력,

는 제1 송신 코일 및 제2 송신 코일에 인가되는 전압과 전류의 주파수,

는 송신 코일의 리액턴스,

는 제1 송신 코일과 수신 코일 간의 상호 인덕턴스,

는 제2 송신 코일과 수신 코일 간의 상호 인덕턴스를 의미한다.In Equation 1

Power transmission efficiency,

Silver output power,

Is the input power,

Is power consumption of the first transmission coil,

Is power consumption of the second transmission coil,

Is the power consumption of the receiving coil,

Is the frequency of the voltage and current applied to the first transmission coil and the second transmission coil,

Is the reactance of the transmitting coil,

Is the mutual inductance between the first transmitting coil and the receiving coil,

Denotes mutual inductance between the second transmitting coil and the receiving coil.

가 될 때 최대가 된다.Therefore, the power transmission efficiency of the wireless power transmission system

It becomes the maximum when becomes.

2 is a block diagram of a wireless power transmission apparatus 200 according to an embodiment of the present invention.

2, the wireless power transmission apparatus 200 according to an embodiment of the present invention includes an estimator 210, a converter 220, a voltage command generator 230, and a power converter 240. do.

The estimator 210 estimates mutual inductance angles between the plurality of transmitting coils and the receiving coils based on currents and voltages of the first transmitting coils and the second transmitting coils, respectively.

Specifically, the mutual inductance angle can be represented by using Equation 2 below.

과

의 비는 아래 수학식 3을 이용하여 산출할 수 있다.At this time,

and

The ratio of can be calculated using Equation 3 below.

는 제1 송신 코일 및 제2 송신 코일의 리액턴스를 의미한다.In equation (3)

Denotes reactance of the first transmission coil and the second transmission coil.

Therefore, the estimator 210 may estimate the mutual inductance angle using Equation 4 below.

The converter 220 demodulates the current of each of the first transmitting coil and the second transmitting coil, and converts each of the demodulated currents into the d-axis current and the q-axis current by using the mutual inductance angle estimated by the estimator 210. Convert to

는 α축 전류를 의미하고,

는 β축 전류를 의미한다. 구체적으로 복조부는

및

를 복조하여 α축 전류 및 β축 전류 각각에 대한 포락선인

및

를 검출할 수 있다.According to an embodiment of the present invention, the conversion unit 220 demodulates the α-axis current flowing in the first transmission coil and the β-axis current flowing in the second transmission coil, respectively, so that the envelope for each of the α-axis current and β-axis current is respectively. It may include a demodulator for detecting. At this time,

Is the α-axis current,

Denotes β-axis current. Specifically, the demodulator

And

Is demodulated by the envelope for α-axis current and β-axis current, respectively.

And

Can be detected.

In addition, according to an embodiment of the present invention, the conversion unit 220, based on the mutual inductance angle, the envelope of the α-axis current and the envelope of the β-axis current detected by the demodulation unit, respectively, d-axis current and q-axis current It may include a dq conversion unit to convert to. Specifically, the d-q converter may convert the envelope of the α-axis current and the envelope of the β-axis current into d-axis current and q-axis current, respectively, using Equation 5 below.

는 d축 전류,

는 q축 전류를 의미한다.In equation (5)

Is the d-axis current,

Is the q-axis current.

The voltage command generator 230 generates an α-axis voltage command and a β-axis voltage command for maximum power transfer based on the d-axis current command, q-axis current command, d-axis current, q-axis current, and mutual inductance angle. .

)은 I로, q축 전류 명령(

)은 0으로 설정할 수 있다.In this case, the d-axis current command and the q-axis current command may be a value set by a user or set in a voltage controller configured separately. For example, the d-axis current command (

) Is I, the q-axis current command (

) Can be set to 0.

According to an embodiment of the present invention, the voltage command generation unit 230 generates a d-axis voltage command and a q-axis voltage command by using a d-axis current command, a q-axis current command, a d-axis current and a q-axis current. It may include a proportional integral controller.

In detail, the proportional integral controller may receive the d-axis current, the q-axis current, the d-axis current command, and the q-axis current command to perform the proportional control and the integral control. The proportional integral controller may generate the d-axis voltage command and the q-axis voltage command by controlling the input d-axis current and q-axis current by an error between the d-axis current command and the q-axis current command, respectively.

Further, according to an embodiment of the present invention, the voltage command generation unit 230 generates the d-axis voltage command and the q-axis voltage command generated by the proportional integration controller based on the mutual inductance angle, respectively, the α-axis voltage command and β. It may include a dq inverse transform unit for converting the axis voltage command.

In detail, the d-q inverse converter may convert the d-axis voltage command and the q-axis voltage command into an α-axis voltage command and a β-axis voltage command, respectively, using Equation 6 below.

는 α축 전압 명령,

는 β축 전압 명령이다.In equation (6)

Is the α-axis voltage command,

Is the β-axis voltage command.

The power converter 240 supplies a high frequency voltage to each of the first transmitting coil and the second transmitting coil based on the α axis voltage command and the β axis voltage command.

According to an embodiment of the present invention, the power conversion unit 240 is based on the α-axis voltage command and β-axis voltage command generated by the voltage command generation unit 230, to the first transmission coil and the second transmission coil It may include a DC-DC converter for controlling the magnitude of the α-axis voltage and β-axis voltage applied respectively.

Specifically, the DC-DC converter may control the magnitudes of the α-axis voltage and the β-axis voltage applied to the first transmitting coil and the second transmitting coil, respectively, according to the magnitude of the voltage according to the α-axis voltage command and the β-axis voltage command. .

In addition, according to an embodiment of the present invention, the power converter 240 modulates the α-axis voltage and the β-axis voltage whose magnitude is controlled by the DC-DC converter, and supplies them to the first transmission coil and the second transmission coil, respectively. It may include a resonant inverter for generating a high frequency voltage.

In detail, the resonant inverter may generate a high frequency voltage by modulating the frequencies of the α-axis voltage and the β-axis voltage at high frequency, and supply the generated high frequency voltage to the first transmitting coil and the second transmitting coil. In this case, the high frequency voltage may be, for example, a voltage having a frequency of 536 kHz. In addition, the frequency of the high frequency voltage supplied to each of the first transmitting coil and the second transmitting coil may correspond to a resonance frequency of capacitance and inductance included in each of the first transmitting coil and the second transmitting coil.

Meanwhile, in an embodiment of the present invention, the estimator 210, the converter 220, the voltage command generator 230, and the power changer 240 illustrated in FIG. 2 are connected to at least one processor and the processor. It may be implemented on one or more computing devices including a computer readable recording medium. The computer readable recording medium may be inside or outside the processor and may be connected with the processor by various well-known means. A processor within the computing device may cause each computing device to operate according to the example embodiments described herein. For example, a processor may execute instructions stored on a computer readable recording medium, and the instructions stored on the computer readable recording medium cause the computing device to operate in accordance with the exemplary embodiment described herein when executed by the processor. It can be configured to perform these.

3 is a flowchart of a wireless power transmission method according to an embodiment of the present invention.

The method illustrated in FIG. 3 may be performed by, for example, the wireless power transmission apparatus 200 illustrated in FIG. 2.

Referring to FIG. 3, the wireless power transmission apparatus 200 estimates mutual inductance angles between a plurality of transmitting coils and a receiving coil based on currents and voltages of each of the first transmitting coil and the second transmitting coil (S310).

Thereafter, the wireless power transmission apparatus 200 demodulates currents of each of the first transmission coil and the second transmission coil (S320), and converts each demodulated current into a d-axis current and a q-axis current using mutual inductance angles. (S330).

In this case, the wireless power transmission apparatus 200 may demodulate the α-axis current of the first transmission coil and the β-axis current of the second transmission coil, respectively, and detect an envelope for each of the α-axis current and the β-axis current.

In addition, the wireless power transmitter 200 may convert the envelope of the α-axis current and the envelope of the β-axis current into d-axis current and q-axis current, respectively, based on the mutual inductance angle.

Subsequently, the wireless power transmitter generates an α-axis voltage command and a β-axis voltage command for maximum power transmission based on the d-axis current command, q-axis current command, d-axis current, q-axis current, and mutual inductance angle ( S340).

In this case, the wireless power transmitter 200 may generate a d-axis voltage command and a q-axis voltage command by using the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current.

In addition, the wireless power transmitter 200 may convert the d-axis voltage command and the q-axis voltage command into an α-axis voltage command and a β-axis voltage command, respectively, based on the mutual inductance angle (S350).

Subsequently, the wireless power transmitter 200 supplies a high frequency voltage to each of the first transmitting coil and the second transmitting coil based on the α-axis voltage command and the β-axis voltage command.

In this case, the wireless power transmission apparatus 200 may control the magnitudes of the α-axis voltage and the β-axis voltage applied to the first transmission coil and the second transmission coil, respectively, based on the α-axis voltage command and the β-axis voltage command. (S360).

In addition, the wireless power transmission apparatus 200 may generate a high frequency voltage by modulating the amplitude-controlled α-axis voltage and β-axis voltage (S370).

In the flowchart illustrated in FIG. 3, the method is divided into a plurality of steps, but at least some of the steps may be performed in a reverse order, in combination with other steps, omitted, or divided into detailed steps. May be performed in addition to one or more steps not shown.

In addition, embodiments of the present invention may include a computer readable recording medium including a program for performing the methods described herein on a computer. The computer-readable recording medium may include program instructions, local data files, local data structures, etc. alone or in combination. The media may be those specially designed and constructed for the purposes of the present invention, or those conventionally available in the field of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical recording media such as CD-ROMs, DVDs, magnetic-optical media such as floppy disks, and ROM, RAM, flash memory, and the like. Hardware devices specifically configured to store and execute program instructions are included. Examples of program instructions may include high-level language code that can be executed by a computer using an interpreter as well as machine code such as produced by a compiler.

While the exemplary embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. . Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

200: wireless power transmission device
210: estimator
220: converter
230: voltage command generation unit
240: power conversion unit

Claims (8)

A two-dimensional wireless power transmission apparatus for transmitting power to a receiving coil by using a plurality of transmitting coils including a first transmitting coil disposed on an α axis and a second transmitting coil arranged on a β axis,
An estimator for estimating mutual inductance angles between the plurality of transmitting coils and the receiving coils based on currents and voltages of the first transmitting coils and the second transmitting coils;
A converter configured to demodulate currents of each of the first transmission coil and the second transmission coil, and convert the demodulated currents into d-axis current and q-axis current using the mutual inductance angle;
a voltage command generation unit for generating an α-axis voltage command and a β-axis voltage command for maximum power transfer based on a d-axis current command, a q-axis current command, the d-axis current, the q-axis current, and the mutual inductance angle; And
And a power converter configured to supply a high frequency voltage to each of the first transmitting coil and the second transmitting coil based on the α axis voltage command and the β axis voltage command.
The method according to claim 1,
The converting unit includes: a demodulator for demodulating the α-axis current of the first transmitting coil and the β-axis current of the second transmitting coil, respectively, and detecting an envelope for each of the α-axis current and the β-axis current; And
And a dq converter configured to convert the envelope of the α-axis current and the envelope of the β-axis current into the d-axis current and the q-axis current, respectively, based on the mutual inductance angle.
The method according to claim 1,
The voltage command generation unit may include: a proportional integral controller configured to generate a d-axis voltage command and a q-axis voltage command using the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current; And
And a dq inverse converter configured to convert the d-axis voltage command and the q-axis voltage command into the α-axis voltage command and the β-axis voltage command, respectively, based on the mutual inductance angle.
The method according to claim 1,
The power converter is configured to control the magnitude of the α-axis voltage and the β-axis voltage applied to the first transmission coil and the second transmission coil based on the α-axis voltage command and the β-axis voltage command. A converter; And
And a resonant inverter configured to generate the high frequency voltage by modulating the α-axis voltage and the β-axis voltage whose size is controlled.
In the two-dimensional wireless power transmission method for transmitting power to the receiving coil using a plurality of transmitting coils including a first transmitting coil disposed on the α axis and a second transmitting coil disposed on the β axis,
Estimating mutual inductance angles between the plurality of transmitting coils and the receiving coils based on currents and voltages of the first transmitting coils and the second transmitting coils;
Demodulating currents of each of the first transmitting coil and the second transmitting coil, and converting each of the demodulated currents into a d-axis current and a q-axis current using the mutual inductance angle;
generating an α-axis voltage command and a β-axis voltage command for maximum power transfer based on a d-axis current command, a q-axis current command, the d-axis current, the q-axis current and the mutual inductance angle; And
And supplying a high frequency voltage to each of the first transmitting coil and the second transmitting coil based on the α axis voltage command and the β axis voltage command.
The method according to claim 5,
The converting may include demodulating the α-axis current of the first transmission coil and the β-axis current of the second transmission coil, respectively, to detect an envelope for each of the α-axis current and the β-axis current; And
And converting the envelope of the α-axis current and the envelope of the β-axis current into the d-axis current and the q-axis current, respectively, based on the mutual inductance angle.
The method according to claim 5,
The generating may include generating a d-axis voltage command and a q-axis voltage command by using the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current; And
And converting the d-axis voltage command and the q-axis voltage command into the α-axis voltage command and the β-axis voltage command, respectively, based on the mutual inductance angle.
The method according to claim 5,
The supplying may include controlling the magnitudes of the α-axis voltage and the β-axis voltage applied to the first transmitting coil and the second transmitting coil, respectively, based on the α-axis voltage command and the β-axis voltage command; And
And generating the high frequency voltage by modulating the amplitude-controlled α-axis voltage and the β-axis voltage.

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