KR20200060884A - Wireless power transmission method and apparatus - Google Patents

Abstract

A wireless power transmission apparatus according to an embodiment comprises: a buck booster to convert direct DC power into second DC power; an inverter to generate AC power based on the second DC power; an antenna to transmit the AD power in a wireless scheme; and a controller to control the buck booster based on required power of a receiver. The buck booster comprises: a first switch disposed between a power line and a common inductor; and a second switch disposed between the common inductor and the inverter. The controller selects a mode of the buck booster. The mode of the buck booster includes: a first mode where the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched with a duty rate of 0%; a second mode where the first switch is switched between a second duty rate and a maximum duty rate based on the required power, and the second switch is switched with a minimum duty rate; and a third mode where the first switch is switched with the maximum duty rate based on the required power, and the second switch is switched between the minimum duty rate and the maximum duty rate. The first duty rate is smaller than the maximum duty rate and is greater than the second duty rate.

Description

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

The present embodiment relates to a wireless power transmission apparatus, and more particularly, to a wireless power transmission method and apparatus capable of supplying various levels of power and maximizing power transmission efficiency at a low manufacturing cost.

Wireless power transmission technology has recently received attention.

Wireless power transmission technology (wireless power transmission or wireless energy transfer) is a technology that wirelessly transmits electric energy from a transmitter to a receiver using the induction principle of a magnetic field. An electric motor or transformer using the electromagnetic induction principle was already used in the 1800s. Since then, a method of transmitting electric energy by radiating electromagnetic waves such as radio waves, microwaves, and lasers has been attempted. Electric toothbrushes and some wireless shavers that we commonly use are actually charged using the electromagnetic induction principle.

Until now, the energy transmission method using wireless can be largely classified into a magnetic induction method, an electromagnetic resonance method, and an RF transmission method using a short-wavelength radio frequency.

The magnetic induction method is a technology that uses the phenomenon that the magnetic flux generated at this time causes electromotive force in another coil when two coils are adjacent to each other and then a current flows through one coil, and is rapidly commercialized around small devices such as mobile phones. Is going on.

The magnetic induction method can transmit power up to hundreds of kilowatts (kW) and has high efficiency, but the maximum transmission distance is less than 1 centimeter (cm).

The magnetic resonance method is characterized by using an electric field or a magnetic field instead of using electromagnetic waves or current. Since the magnetic resonance method is hardly affected by electromagnetic wave problems, it has the advantage of being safe for other electronic devices or the human body.

On the other hand, it can be used only in a limited distance and space, and has a disadvantage in that energy transfer efficiency is somewhat low. The short-wavelength wireless power transmission method-simply, the RF transmission method-utilizes the point that energy can be directly transmitted and received in the form of a radio wave.

This technology is a wireless power transmission method of an RF method using a rectenna, and a rectenna is a compound word of an antenna and a rectifier, which means a device that directly converts RF power into direct current power.

That is, the RF method is a technique of converting and using AC radio waves to DC. Recently, as efficiency has improved, research on commercialization has been actively conducted. In addition, wireless power transmission technology can be used in a variety of industries, such as IT, railroad, home appliance industry as well as mobile.

Accordingly, there is a need for a wireless power transmission device that supplies various levels of wireless power.

Wireless charging is also important to maximize charging efficiency, but it is also important to minimize heat generation.

In a conventional wireless power transmission apparatus, a dual-mode full-bridge inverter that switches half-bridge and full-bridge is used to supply various levels of power required by various types of receivers.

However, the use of a dual-mode full-bridge inverter not only increases the price of the wireless power transmission device, but also has a problem of lowering heat loss and efficiency. In addition, the wireless power transmission apparatus that adjusts the intensity of transmission power by changing the operating frequency applied to the inverter has a problem that may cause electromagnetic interference to peripheral devices.

The embodiments are designed to solve the problems of the above-described prior art, and an object of the embodiments is to provide a wireless power transmission method and apparatus capable of supplying various levels of power.

Another object of the embodiment is to provide a wireless power transmission method and apparatus having excellent efficiency and heat generation performance.

Another object of the embodiment is to provide a wireless power transmission method and apparatus capable of preventing electromagnetic interference in advance by having a half-bridge inverter operating at a fixed operating frequency.

The technical problems to be achieved in the embodiments are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary knowledge in the technical field to which the present invention belongs from the following description. Will be able to.

A wireless power transmission apparatus according to an embodiment includes a buck booster that converts first DC power to second DC power and outputs the converted DC power; An inverter that generates AC power based on the second DC power; An antenna for wirelessly transmitting the AC power; And a controller that controls the buck booster based on the required power of the receiver, wherein the buck booster comprises: a first switch disposed between a power line and a common inductor, and a second switch disposed between the common inductor and the inverter. A switch, the controller selects the mode of the buck booster, the mode of the buck booster is the first switch is switched between the minimum duty rate and the first duty rate based on the required power, 0% A first mode in which the second switch is switched at a duty rate, and the first switch is switched between a second duty rate and a maximum duty rate based on the required power, and the second switch is switched at a minimum duty rate A second mode and a third mode in which the first switch is switched at a maximum duty rate based on the required power, and the second switch is switched between a minimum duty rate and a maximum duty rate, and the first duty The rate is smaller than the maximum duty rate and greater than the second duty rate.

In addition, a demodulator for demodulating the control signal received through the antenna, the controller, based on the required power of the receiver included in the control signal, selects the mode of the buck booster, and within the selected mode The duty rates of the first switch and the second switch are determined.

In addition, the first switch is connected to a decompression circuit that depressurizes and outputs the voltage of the first DC power, and the second switch is connected to a step-up circuit that boosts and outputs the voltage of the first DC power.

Further, the minimum duty rate is greater than the 0% duty rate, and the maximum duty rate is less than the 100% duty rate.

Further, the first duty rate corresponds to a duty rate obtained by subtracting the minimum duty rate from the maximum duty rate.

Further, the second duty rate corresponds to a duty rate obtained by subtracting the minimum duty rate from the first duty rate.

In addition, the control unit outputs a first signal corresponding to the determined duty rate of the first switch to the first switch, and the second signal corresponding to the determined duty rate of the second switch to the second switch Output to

In addition, the controller determines the sum of the duty rate of the first signal and the duty rate of the second signal based on the requested power, and based on the determined sum, the duty rate and the second of the first signal 2 Determine the duty rates of the signals, respectively.

Meanwhile, a wireless power transmission method according to an embodiment includes demodulating a control signal received through an antenna; Determining a required power of a receiver based on the demodulated control signal; Selecting a mode of the buck booster based on the determined required power; And controlling the buck booster based on the selected mode, wherein the buck booster includes a first switch disposed between the power line and a common inductor, and a second switch disposed between the common inductor and the inverter. The buck booster mode includes a first mode in which the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched at a duty rate of 0%. , A second mode in which the first switch is switched between a second duty rate and a maximum duty rate based on the requested power, and the second switch is switched at a minimum duty rate, and a maximum duty rate based on the requested power And including the third mode in which the first switch is switched, and the third mode is switched between a third duty rate and a maximum duty rate, wherein the first duty rate is less than the maximum duty rate and the second Greater than the duty rate.

Further, the minimum duty rate is greater than the 0% duty rate, and the maximum duty rate is less than the 100% duty rate.

Further, the first duty rate corresponds to a duty rate obtained by subtracting the minimum duty rate from the maximum duty rate.

Further, the second duty rate corresponds to a duty rate obtained by subtracting the minimum duty rate from the first duty rate.

The present invention provides a buck mode, a boost mode, and a buck booster operating in a buck-boost mode between the buck mode and the boost mode, and accordingly, the buck mode, the boost mode and the buck-boost according to the power required by the wireless power receiver. The buck booster operates in any one of the modes.

According to this, in the present invention, frequent mode switching to a single operation mode such as a buck mode and a boost mode can be prevented, and accordingly, a stable system can be operated.

In addition, the present invention has an advantage of providing a wireless power transmission method and apparatus capable of supplying various levels of power. An embodiment is a buck mode, a boost mode, and a buck operating in a buck-boost mode between the buck mode and the boost mode. A booster is provided, and accordingly, the buck booster operates in one of a buck mode, a boost mode, and a buck-boost mode according to the power required by the wireless power receiver.

According to this, in the embodiment, frequent mode switching to a single operation mode such as a buck mode and a boost mode can be prevented, and accordingly, a stable system can be operated.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus capable of supplying various levels of power.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus excellent in efficiency and heat generation performance.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus capable of preventing electromagnetic interference in advance by having a half-bridge inverter operating at a fixed operating frequency.

In addition, the embodiment is advantageous in that it is possible to provide a wireless power transmission method and apparatus having a simple manufacturing cost and structure by controlling only the direct voltage applied to the inverter to control the transmission power.

The effects obtained in the embodiments are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description. will be.

1 is a block diagram illustrating a wireless charging system according to an embodiment.
2 is a block diagram illustrating a wireless charging system according to another embodiment.
3 is a block diagram illustrating a structure of a wireless power transmission apparatus according to an embodiment.
4 is a state transition diagram for describing a wireless power transmission procedure according to an embodiment.
5 is a state transition diagram for describing a wireless power transmission procedure according to another embodiment.
6 is a block diagram illustrating a detailed structure of a wireless power transmission apparatus according to an embodiment.
7 is a view for explaining the operation of the half-bridge inverter in one embodiment.
8 is a view for explaining the operation of the full-bridge inverter according to another embodiment.
9 is a block diagram illustrating an operation of a buck booster according to an embodiment.
10 is a block diagram illustrating a detailed configuration of a buck booster according to an embodiment.
11 is an equivalent circuit diagram of a switch provided in a buck booster according to an embodiment.
12 shows an equivalent circuit configuration when the buck booster operates in the buck mode according to an embodiment.
13 shows an equivalent circuit configuration when the buck booster operates in the boost mode according to an embodiment.
14 shows an equivalent circuit configuration when the buck booster operates in the buck-boost mode according to an embodiment.
15 is a flowchart illustrating a method of determining an operation mode of a buck booster in a wireless power transmission apparatus according to an embodiment.
16 is a flowchart illustrating a method for controlling wireless power transmission in a wireless power transmission apparatus according to an embodiment.
17 is a flowchart illustrating a method for controlling wireless power transmission in a buck mode according to an embodiment.
18 is a flowchart illustrating a method for controlling wireless power transmission in a buck-boost mode according to an embodiment.
19 is a flowchart illustrating a method for controlling wireless power transmission in a boost mode according to an embodiment.
20A is a diagram illustrating a method of controlling an operation of a buck booster in a controller of a wireless power transmission apparatus according to an embodiment.
20B is a diagram illustrating a state transition between a first mode and a third mode according to an embodiment.
21 is a view for explaining a method for controlling power transmission in a wireless power transmission system according to an embodiment.
22 is a diagram illustrating a method of controlling an operation point for controlling transmission power in a wireless power transmitter according to an embodiment.

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

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of its components between embodiments may be selectively selected. It can be used by bonding and substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless specifically defined and specifically described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as a meaning, and terms that are commonly used, such as a dictionary-defined term, may interpret the meaning in consideration of the contextual meaning of the related technology. In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, a singular form may also include a plural form unless specifically stated in the phrase, and is combined with A, B, C when described as "at least one (or more than one) of A and B, C". It can contain one or more of all possible combinations. In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only for distinguishing the component from other components, and the term is not limited to the nature, order, or order of the component. And, when a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also to the component It may also include a case of'connected','coupled' or'connected' due to another component between the other components.

Further, when described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other It also includes a case in which another component described above is formed or disposed between two components. In addition, when expressed as "up (up) or down (down)", it may include the meaning of the downward direction as well as the upward direction based on one component.

In the description of the embodiment, a device equipped with a function for transmitting wireless power on a wireless charging system includes a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a transmitter, a transmitter, and a transmitter for convenience of description. , The transmitting side, a wireless power transmission device, a wireless power transmitter, etc. will be used interchangeably.

In addition, a wireless power receiving device, a wireless power receiver, a wireless power receiving device, a wireless power receiver, a receiving terminal, a receiving side, for convenience of description as an expression of a device equipped with a function for receiving wireless power from the wireless power transmitting device, A receiving device, a receiver, etc. can be used interchangeably.

The transmitter according to the present invention may be configured in a pad shape, a cradle shape, an AP (Access Point) shape, a small base station shape, a stand shape, a ceiling buried shape, a wall-mounted shape, etc., and one transmitter is provided to a plurality of wireless power receiving devices. You can also transmit power.

To this end, the transmitter may include at least one wireless power transmission means. Here, as the wireless power transmission means, a variety of radio power transmission standards based on an electromagnetic induction method that generates a magnetic field in a coil of a power transmitting end and charges it using an electromagnetic induction principle in which electricity is induced in a coil in a receiving end under the influence of the magnetic field may be used.

In addition, the receiver according to an embodiment of the present invention may be provided with at least one wireless power receiving means, and may simultaneously receive wireless power from two or more transmitters.

The receiver according to the present invention is a mobile phone, a smart phone, a laptop computer, a terminal for digital broadcasting, PDA (Personal Digital Assistants), PMP (Portable Multimedia Player), navigation, MP3 player, electric It can be used in small electronic devices such as toothbrushes, electronic tags, lighting devices, remote controllers, fishing boats, wearable devices such as smart watches, but is not limited thereto, and if the device is equipped with a wireless power receiving means according to the present invention and can charge a battery Enough.

1 is a block diagram illustrating a wireless charging system according to an embodiment.

Referring to FIG. 1, the wireless charging system includes a wireless power transmitter 10 that wirelessly transmits power, a wireless power receiver 20 that receives the transmitted power, and an electronic device 20 that receives the received power. Can be configured.

For example, the wireless power transmitting end 10 and the wireless power receiving end 20 may perform in-band communication for exchanging information using the same frequency band as the operating frequency used for wireless power transmission.

As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 perform out-of-band communication for exchanging information using a separate frequency band different from an operating frequency used for wireless power transmission. You can also do

For example, information exchanged between the wireless power transmission end 10 and the wireless power reception end 20 may include control information as well as status information of each other.

Here, the state information and control information exchanged between the transmitting and receiving terminals will become clearer through the description of the embodiments to be described later.

The in-band communication and the out-of-band communication may provide two-way communication, but are not limited thereto, and in other embodiments, one-way communication or half-duplex communication may be provided.

For example, the unidirectional communication may be that the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10, but is not limited thereto, and the wireless power transmitting end 10 sends information to the wireless power receiving end 20. It may be to transmit.

In the half-duplex communication method, two-way communication between the wireless power receiving end 20 and the wireless power transmitting end 10 is possible, but there is a feature that only one device can transmit information at any one time.

The wireless power receiver 20 according to an embodiment may acquire various status information of the electronic device 30.

For example, the status information of the electronic device 30 may include current power usage information, information for identifying a running application, CPU usage information, battery charge status information, battery output voltage/current information, etc., but is not limited thereto. If not, it is sufficient if the information can be obtained from the electronic device 30 and can be used for wireless power control.

In particular, the wireless power transmitter 10 according to an embodiment may transmit a predetermined packet indicating whether to support fast charging to the wireless power receiver 20.

2 is a block diagram illustrating a wireless charging system according to another embodiment.

For example, as shown in reference numeral 200a, the wireless power receiving end 20 may be composed of a plurality of wireless power receiving devices, and a plurality of wireless power receiving devices connected to one wireless power transmitting end 10 may be wirelessly connected. Charging can also be performed.

In this case, the wireless power transmitter 10 may distribute and transmit power to a plurality of wireless power receivers in a time-division manner, but is not limited thereto. As another example, the wireless power transmitter 10 may transmit power by distributing power to a plurality of wireless power receivers using different frequency bands allocated for each wireless power receiver.

At this time, the number of wireless power receiving devices that can be connected to one wireless power transmitting device 10 is at least one of the required power for each wireless power receiving device, the battery charging state, the power consumption of the electronic device, and the available power of the wireless power transmitting device. It can be determined adaptively on the basis of.

As another example, as illustrated in 200b, the wireless power transmitter 10 may be configured with a plurality of wireless power transmitters.

In this case, the wireless power receiver 20 may be connected to a plurality of wireless power transmitters at the same time, and may perform charging by simultaneously receiving power from the connected wireless power transmitters.

At this time, the number of wireless power transmitting devices connected to the wireless power receiving end 20 is adaptively based on the required power of the wireless power receiving end 20, the battery charging state, the power consumption of the electronic device, and the available power of the wireless power transmitting device. Can be determined.

3 is a block diagram illustrating the structure of a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 3, the wireless power transmission apparatus 300 may include a controller 310, a power converter 320, a transmission coil 330, and a demodulator 340.

The power converter 320 may convert DC power into AC power according to the control signal of the controller 310.

The controller 310 according to an embodiment may dynamically change the operation mode of the inverter provided in the power converter 320.

Here, the inverter operation mode may include a half bridge mode and a full bridge mode, and the default mode may be set as a full bridge mode.

The power converter 320 according to another embodiment may be provided with a half-bridge type inverter, so that the inverter operation mode may not be changed.

The detailed configuration of the power converter 320 and the description of the inverter operation mode will become clearer through descriptions of the drawings to be described later.

The transmission coil 330 may be connected to the output terminal of the power converter 320 to wirelessly output AC power.

The demodulator 340 may be connected to one side of the transmission coil 330, and may include an analog digital converter.

The demodulator 340 may deliver the demodulated packet to the controller 310.

The controller 310 may dynamically control transmission power based on a predetermined packet received from the demodulator 340-for example, a control error packet including a control error value.

In addition, the controller 310 is a drive signal having a fixed operating frequency (Operating Frequecy), duty rate (Duty Rate) and phase (Phase), that is, the pulse width modulation signal-the inverter provided in the power converter 320 ( (Not shown).

The controller 310 may control the intensity of the transmission power by adjusting the intensity of the DC voltage applied to the inverter (not shown) of the power converter 320.

An inverter (not shown) provided in the power converter 320 according to the embodiment may be implemented as a half bridge.

As illustrated in FIG. 7 to be described later, the half-bridge circuit may include two switches. Also, as shown in FIG. 8 to be described later, the full bridge circuit may include four switches.

Therefore, the full bridge circuit may have a maximum power amplification ratio of up to twice the half bridge circuit, but the power loss by the switch element may also be up to twice.

In addition, the full bridge circuit has a disadvantage that the unit cost is higher than that of the half bridge circuit.

The full bridge circuit can also be operated in half bridge mode, depending on how the drive signal is controlled, thereby providing a wide range of power.

However, abrupt operation mode conversion in a full bridge circuit, which may be, for example, a transition from half bridge mode to full bridge mode or a transition from full bridge mode to half bridge mode, causes a rapid change in output voltage or current. The wireless power transmission device 300 and the wireless power reception device may be damaged accordingly.

In order to solve this, in the conventional wireless power transmission apparatus, at least one of the following three methods is used for a more gentle power change when the operation mode of the inverter is changed.

1) Change the frequency of the drive signal (variable frequency method)

2) Phase control of the drive signal (phase control method)

3) Duty rate control of driving signal (duty rate control method)

However, the variable frequency method has a disadvantage in that it is difficult to control electromagnetic interference (EMI). Accordingly, when a wireless power transmission device is disposed around an EMI-sensitive device such as a vehicle communication device, an additional element or component for blocking EMI, for example, an EMI filter, is applied to the wireless power transmission device. It should be provided.

This may cause an increase in size/weight/cost of the wireless power transmission device.

However, in recent years, as the application range for the wireless charging technology has been widened, the power range required by the wireless power receiving device is widening.

The embodiment is provided with a low-cost half-bridge circuit rather than a full-bridge circuit with a high price, and by driving the half-bridge circuit with a fixed frequency method rather than a variable frequency method, it is possible to provide a wireless power transmission device having excellent price competitiveness and EMI performance have.

4 is a state transition diagram for describing a wireless power transmission procedure according to an embodiment.

4, the power transmission from the transmitter to the receiver is largely a selection phase (Selection Phase, 410), a ping phase (Ping Phase, 420), identification and configuration phase (Identification and Configuration Phase, 430), power transmission phase ( Power Transfer Phase, 440).

The selection step 410 may be a transition step when a specific error or specific event is detected while starting or maintaining the power transmission.

Here, specific errors and specific events will be clarified through the following description.

In addition, in the selection step 410, the transmitter may monitor whether an object is present on the interface surface.

If the transmitter detects that an object is placed on the interface surface, it may transition to the ping step 420 (S401).

In the selection step 410, the transmitter transmits a very short pulse analog ping signal, and detects whether an object exists in an active area of the interface surface based on a current change of the transmitting coil.

In the ping step 420, when an object is detected, the transmitter activates the receiver, and transmits a digital ping to identify whether the receiver is a receiver that complies with the standard.

In the ping step 420, if the transmitter does not receive a response signal for digital ping (eg, a signal strength indicator) from the receiver, the transmitter may transition to the selection step 410 again (S402).

Also, in the ping step 420, the transmitter may transition to the selection step 410 when receiving a signal indicating that power transmission is completed from the receiver, that is, a charging completion signal (S403).

When the ping step 420 is completed, the transmitter may transition to the identification and configuration step 430 for collecting the receiver identification and receiver configuration and status information (S404).

In the identification and configuration step 430, the transmitter may receive an unsolicited packet (unexpectedpacket), or receive a desired packet for a predefined time (time out), a packet transmission error (transmission error), or a power transmission contract. If it is not set (no power transfer contract), it may be transferred to the selection step 410 (S405).

When identification and configuration of the receiver is completed, the transmitter may transition to a power transmission step 240 of transmitting wireless power (S406).

In the power transmission step 440, the transmitter receives an undesired packet (unexpectedpacket), a desired packet is not received for a predefined time (time out), or a violation of a predetermined power transmission contract occurs (power transfer). contract violation), when charging is completed, the process may transition to the selection step 410 (S407).

In addition, in the power transmission step 440, the transmitter may transition to the identification and configuration step 430 when it is necessary to reconfigure the power transmission contract according to a change in the transmitter state (S408 ).

The above-described power transmission contract may be established based on status and characteristic information of the transmitter and receiver. For example, the transmitter status information may include information on the maximum transmittable power, information on the maximum number of receivers that can be accommodated, and receiver status information may include information on required power.

5 is a state transition diagram for describing a wireless power transmission procedure according to another embodiment.

5, the power transmission from the transmitter to the receiver is largely a selection phase (Selection Phase, 510), a ping phase (Ping Phase, 520), identification and configuration phase (Identification and Configuration Phase, 530), negotiation phase (Negotiation) Phase, 540), a calibration phase (Calibration Phase, 550), a power transfer phase (Power Transfer Phase, 560) phase and a renegotiation phase (Renegotiation Phase, 570).

The selection step 510 may be a transition step when a specific error or specific event is detected while starting or maintaining the power transmission.

Here, specific errors and specific events will be clarified through the following description. In addition, in the selection step 510, the transmitter may monitor whether an object is present on the interface surface.

If the transmitter detects that an object is placed on the interface surface, it may transition to ping step 520. In the selection step 510, the transmitter transmits a very short pulse analog ping signal, and an object in the active area of the interface surface based on the current change of the transmitting coil or the primary coil. Can detect if exists.

In ping step 520, when an object is detected, the transmitter activates the receiver and transmits a digital ping to identify whether the receiver is a WPC standard compliant receiver. In the ping step 520, if the transmitter does not receive a response signal for digital ping-for example, a signal strength packet-from the receiver, the transmitter may transition back to the selection step 510.

In addition, in the ping step 520, the transmitter may transition to the selection step 510 upon receiving a signal indicating that power transmission is completed from the receiver, that is, a charging complete packet.

When the ping step 520 is complete, the transmitter can transition to the identification and configuration step 530 to identify the receiver and collect receiver configuration and status information.

In the identification and configuration step 530, the transmitter may receive an unsolicited packet (unexpectedpacket), a desired packet for a predefined time (time out), or a packet transmission error (transmission error), or a power transmission contract. If it is not set (no power transfer contract), it may transition to the selection step 510.

The transmitter may check whether entry into the negotiation step 540 is necessary based on the value of the negotiation field of the configuration packet received in the identification and configuration step 530.

As a result of the confirmation, if negotiation is required, the transmitter may enter a negotiation step 540 to perform a predetermined FOD detection procedure.

On the other hand, as a result of the confirmation, if negotiation is not required, the transmitter may immediately enter the power transmission step 560.

In the negotiation step 540, the transmitter may receive a Foreign Object Detection (FOD) status packet including a reference quality factor value. At this time, the transmitter may determine a threshold for FO detection based on the reference quality factor value.

The transmitter may detect whether the FO exists in the charging area by using the determined threshold for FO detection and the currently measured quality factor value, and may control power transmission according to the FO detection result. For example, when a FO is detected, power transmission may be stopped, but is not limited thereto.

If an FO is detected, the transmitter can return to selection step 510. On the other hand, if the FO is not detected, the transmitter may enter the power transmission step 560 through a correction step 550.

In detail, when the FO is not detected, the transmitter determines the strength of the power received at the receiving end in the correction step 550, and the power loss at the receiving end and the transmitting end is determined to determine the strength of the power transmitted from the transmitting end. Can be measured.

That is, the transmitter may predict power loss based on the difference between the transmit power of the transmitting end and the receiving power of the receiving end in the correction step 550.

The transmitter according to an embodiment may correct the threshold for FOD detection by reflecting the predicted power loss.

In the power transmission step 540, the transmitter may receive an unexpected packet (unexpected packet), or receive a desired packet for a predefined time (time out), or a violation of a predetermined power transmission contract (power) transfer contract violation), when the charging is completed, may transition to the selection step 510.

In addition, in the power transmission step 440, the transmitter may transition to the renegotiation step 570 when it is necessary to reconfigure the power transmission contract according to a change in the transmitter state.

At this time, when the renegotiation is normally completed, the transmitter may return to the power transmission step 560.

The above-described power transmission contract may be established based on status and characteristic information of the transmitter and receiver. For example, the transmitter status information may include information on the maximum transmittable power, information on the maximum number of receivers that can be accommodated, and receiver status information may include information on required power.

6 is a block diagram illustrating a detailed structure of a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 6, the wireless power transmitter 600 may be configured to include a controller 610, a power converter 620, an antenna 630, and a demodulator 640.

Here, the power converter 623 may include a gate driver (Gate Driver 622), a half bridge inverter (Half Bridge Invertor, 622) and a buck booster (Buck Booster) 623.

The power converter 620 converts the first DC power applied from the power source 650 to the second DC power, and then generates first to first signals based on a reference clock (Ref_CLK) received from the controller 610. The second DC power may be converted into AC power using the two switch control signals SC_0 and SC_1, and provided to the antenna 630.

In this embodiment, the antenna 630 may be configured to include an LC resonant circuit composed of at least one inductor (L) and at least one capacitor (Capacitor, C).

In one embodiment, the antenna 630 may be in the form of a single coil consisting of one coil, that is, one inductor, but this is only one embodiment, and the antenna 630 according to another embodiment may include a plurality of coils. It can also be configured.

Hereinafter, the DC voltage corresponding to the second DC power-that is, the voltage applied to the half-bridge inverter 622-will be referred to as an inverter input voltage or V-rail.

Here, the first to second switch control signals SC_0 and SC_1 may be pulse width modulation signals.

The power converter 620 is an AC/DC converter (not shown) that is disposed before the buck booster 623 and converts an AC signal into a DC signal when the type of power applied from the power source 650 is AC. ) May be further included.

The gate driver 621 generates first to second switch control signals SC_0 and SC_1 for controlling two switches provided in the half bridge inverter 622 using the reference clock received from the controller 610. Can be.

Here, the frequency of the reference clock and the phase and duty rate of the first to second switch control signals SC_0 and SC_1 may be fixed. For example, the frequency of the reference clock is fixed at 110 KHz, and the phase and duty rate of the first to second switch control signals SC_0 and SC_1 may be fixed at 0 and 50%, respectively. It should be noted that this is only an example, and may be set differently according to the design of a person skilled in the art.

That is, the wireless power transmission apparatus 600 according to the embodiment may operate in a fixed frequency method rather than a variable frequency method.

In addition, the wireless power transmission apparatus 600 according to the embodiment does not control the phase and duty rate of the pulse width modulated signal applied to the half bridge inverter 622, and the output voltage of the buck booster 623-that is, V rail -By controlling only the intensity of power transmitted through the antenna 630 can be controlled.

The buck booster 623 according to an embodiment may operate in any one of the first mode, the second mode, and the third mode according to the control signal of the controller 610. At this time, the first mode may be a buck mode. In addition, the second mode may be a buck-boost mode. Also, the third mode may be a boost mode.

For example, when the power to be transmitted to the wireless power receiver is less than the first power, the controller 610 may control the buck booster 623 to operate in the buck mode.

If the power to be transmitted to the wireless power receiver exceeds the second power, the controller 610 may control the buck booster 623 to operate in the boost mode. Here, the second power is greater than the first power.

On the other hand, when the power to be transmitted to the wireless power receiver is less than the first power or the second power, the controller 610 may control the buck booster 623 to operate in the buck-boost mode.

The detailed configuration of the buck booster 623 and the method in which the output voltage is controlled in the buck booster 623 will become clearer through the description of the drawings to be described later.

The half-bridge inverter 622 converts the V-rail, which is a DC voltage, into an AC voltage based on the first to second switch control signals SC_0 and SC_1 received through the gate driver 621, thereby converting the antenna 630. Can be provided on.

The controller 610 may dynamically control the output voltage of the buck booster 623 based on the control error packet received through the demodulator 640.

For example, the maximum output voltage of the buck booster 623 is 25V, and accordingly, the maximum charging power may be 15W, but this is only one embodiment, and the maximum output voltage of the buck booster 623 according to the design of a person skilled in the art And it should be noted that the maximum charging power may be designed differently.

The method by which the controller 610 controls the output voltage of the buck booster 623 will become clearer through the description of the drawings to be described later.

As described above, since the wireless power transmission apparatus 600 according to the embodiment operates in a fixed frequency method, EMI performance may be improved.

In addition, since the wireless power transmission apparatus 600 according to the embodiment does not change the inverter operation mode, it has an advantage that it is possible to prevent damage to the device due to a sudden voltage change when the inverter mode is changed.

In addition, the wireless power transmission apparatus 600 according to the embodiment is provided with a low-bridge half-bridge circuit with a small number of switches instead of a full-bridge circuit having a high price, so that it is not only high in price competitiveness but also capable of improving efficiency and heat loss There is this.

7 and 8 are views for explaining the operation of the inverter.

Referring to FIG. 7, the half-bridge inverter includes two switches S1 and S2, and the corresponding switch is ON/OFF controlled according to the PWM signal of the gate driver to change the output voltage Vo. For example, as illustrated in 710, when the S1 switch is shorted and the S2 switch is opened, the output voltage Vo has an input voltage +Vdc. On the other hand, when the S1 switch is opened and the S2 switch is shorted, the output voltage Vo has a value of zero.

The half bridge inverter receives the first to second PWM signals having different phases from the gate driver, and may control the S1 switch and the S2 switch using the first to second PWM signals. When the S1 switch and the S2 switch are cross-shorted according to the first to second PWM signals, the half bridge inverter may output an AC power signal having a specific period.

Referring to FIG. 8, the full bridge inverter may include four switches S1, S2, S3, and S4, and the corresponding switch may be ON/OFF controlled according to the PWM signal received from the gate driver.

The output voltage (Vo) level of the full bridge inverter may have a value of +Vdc or -Vdc or 0, as shown in FIG.

For example, when the S1 switch and the S2 switch are short-circuited and the remaining switches are opened, the output voltage (Vo) level has a value of +Vdc. On the other hand, when the S3 switch and the S4 switch are short-circuited and the remaining switches are opened, the output voltage (Vo) level has a value of -Vdc.

9 is a block diagram illustrating the operation of a buck booster according to an embodiment.

Referring to FIG. 9, the buck booster 900 may include a first circuit 910, a second circuit 920 and a common inductor 930.

As illustrated in FIG. 9, the common inductor 930 is disposed between the first circuit 910 and the second circuit 920 and can be electrically connected to the first circuit 910 and the second circuit 920. have.

The first circuit 910 may include a step-down circuit that converts the output voltage V_rail to an input voltage V_in or less, and the second circuit 920 may include a step-up circuit that converts the output voltage to an input voltage or higher. have. In other words, the first circuit 910 may be a buck converter, and the second circuit 920 may be a boost converter.

In the first circuit 910, the degree of decompression is adjusted based on the duty rate of the first signal 940, and in the second circuit 920, the degree of boosting is adjusted based on the duty rate of the second signal 950. Can be.

Here, the first signal 940 and the second signal 950 are pulse widths received from the controller 610 of FIG. 6 or the pulse width modulation signal controller (not shown) controlled by the controller 610 described above. It may be a modulated signal.

The controller 610 controls the level and duty rate of the first signal 940 and the second signal 950 to output the voltage through the second circuit 920, that is, the output voltage of the buck booster 900 You can control the rail (V_rail).

Here, the levels of the first signal 940 and the second signal 950 may be divided into a first level “” level and a second level “” level.

The first signal 940 and the second signal 950 are first switches 911 and second switches provided in the first circuit 910 and the second circuit 920, as shown in FIG. 10 to be described later. It may be a switch control signal for controlling (921).

For example, when the level of the first signal 940 is “”, the switch provided in the first circuit 910 is shorted, and when the level of the first signal 940 is “”, the first circuit 910 is in the first circuit 910. The provided switch can be opened.

In addition, when the level of the second signal 950 is “”, the switch provided in the second circuit 920 is shorted, and when the level of the second signal 950 is “”, the second circuit 930 is provided in the second circuit 930. Switch can be opened.

If the level of the first signal 940 is maintained in the “” state, the buck booster 900 may operate in the boost mode and output a voltage greater than the input voltage V_in.

At this time, the intensity of the output voltage may be determined in proportion to the duty rate of the second signal 950.

For example, in the boost mode, the output voltage of the buck booster 900 may be amplified up to approximately twice the input voltage V_in, but is not limited thereto, and the boosting level may be different according to the design of a person skilled in the art. .

For example, when the intensity of the input voltage is 13V and the buck booster 900 operates in the boost mode, the maximum output voltage of the buck booster 900 through the control of the second signal 950 may be 25V. Here, when the output voltage of the buck booster 900 is 25V, the wireless power transmission device may provide 15W charging to the corresponding wireless power receiver.

On the other hand, when the level of the second signal 950 is maintained in the “” state, the buck booster 900 may operate in the buck mode and output a voltage lower than the input voltage V_in. At this time, the output voltage of the buck booster 900 may be determined in proportion to the duty rate of the first signal 940.

If, the first signal 940 is a pulse width modulated signal having a duty range of a certain range without continuously maintaining the first level, and the second signal 950 is not a "LOW" state, but a specific second level is maintained. In the case of a pulse width modulated signal, the buck booster 900 may operate in a buck-boost mode. Here, the “LOW” state may mean a duty rate of 0%.

The buck booster 900 according to an embodiment may operate in a buck mode, a boost mode, and a buck-boost mode at a specific time point according to the first signal 940 and the second signal 950. In this case, substantially, the buck mode, the boost mode, and the buck-boost mode may be determined by the amount of power required by the wireless power receiver. However, when the required power is greater than or equal to the first power and less than or equal to the second power, the buck booster 900 may operate in a buck-boost mode. At this time, when the buck-boost mode is operated, the maximum duty rate that the first signal 940 can have and the minimum duty rate that the second signal 950 can have (here, the minimum duty rate is'Low '0% corresponding to the state can be determined based on). This will be described in more detail below.

On the other hand, when the buck booster 900 operates in a buck mode or a boost mode, the buck booster 900 is controlled such that only one of the two switches provided is driven, and thus switching loss can be minimized. . In addition, since the buck booster 900 is controlled so that only one of the two switches is switched by the PWM signal, it is also possible to prevent overcurrent from flowing into the common inductor 930 due to a sudden voltage change. have.

In addition, when the buck booster 900 operates in a buck-boost mode, the buck booster 900 may be controlled such that both switches provided are driven.

In other words, if the required power of the receiver is less than the first power, the buck booster 900 is controlled to operate in the buck mode, and if the required power of the receiver exceeds the second power, the buck booster 900 operates in the boost mode. Can be controlled.

On the other hand, if the required power of the receiver is the first power or less than the second power, the buck booster 900 may be controlled to operate in a buck-boost mode. Here, the second power is greater than the first power.

In the buck-boost mode, the duty rates of the first signal 940 and the second signal 950 may be determined corresponding to the power demand of the receiver. Decompression and boosting may be respectively performed in the first circuit 910 and the second circuit 920 according to the determined duty rates of the first signal 940 and the second signal 950. At this time, the first signal 940 in the embodiment may vary within a certain range according to the required power of the receiver in the buck-boost mode. Alternatively, the second signal 950 within the buck-boost mode can maintain a certain duty rate. At this time, the duty rate of the second signal 950 has a value greater than 0%. Preferably, the second signal 950 within the buck-boost mode can maintain a minimum duty rate. At this time, the minimum duty rate may be 5%. However, this is only an embodiment, and the minimum duty rate may be changed according to an embodiment.

10 is a block diagram illustrating a detailed configuration of a buck booster according to an embodiment.

Referring to FIG. 10, the buck booster 1000 may include a first circuit 1010, a second circuit 1020 and a common inductor 1030.

Here, the first circuit 1010 is composed of a decompression circuit 1011 and a first constant voltage circuit 1012, and the second circuit 1020 includes a second constant voltage circuit 1021 and a boosting circuit 1022. Can be.

In the buck mode, the level of the second signal 1050 is maintained at “”, so that the boosting circuit 1022 is inactive—that is, the internal switch of the boosting circuit 1022 remains open (OPEN)-, the decompression circuit ( The duty rate of the first signal 1040 applied to 1011) is adjusted to control the output voltage V_Rail of the buck booster 1000.

In the boost mode, the level of the first signal 1040 is maintained at the maximum duty rate, so that the decompression circuit 1011 is conducting, and the duty rate of the second signal 1050 applied to the boosting circuit 1022 is adjusted to buck booster. The output voltage V_Rail of 1000 may be controlled.

Here, the conduction of the decompression circuit 1011 may mean that a switch provided inside the decompression circuit 1011 operates at a duty rate of 90%, so that the input current I_in of the buck booster 100 is As it is, it may mean that it is transmitted to the common inductor 1030.

In the buck-boost mode, the levels of the first signal 1040 and the second signal 1050 applied to the step-down circuit 1011 and the step-up circuit 1022, respectively, are not maintained at the maximum duty rate or “”. That is, each of the first signal 1040 and the second signal 1050 may be pulse width modulated signals having a duty rate determined according to the required power of the receiver. That is, the first signal 1040 may be a pulse width modulated signal having a duty rate that changes according to the required power of the receiver. Also, the first signal 1050 may be a pulse width modulated signal with a specific duty rate maintained regardless of the required power of the receiver. Here, the specific duty rate may have a level greater than 0%. Preferably, the specific duty rate may be a minimum duty rate that the boosting circuit 1022 may have. For example, the minimum duty rate may be 5%.

That is, in general, the level of the first signal 1040 and the second signal 1050 applied to the decompression circuit 1011 and the step-up circuit 1022, respectively, can be controlled from 0% to 100%. However, in an embodiment, a minimum duty rate and a maximum duty rate are set for each duty rate of the first signal 1040 and the second signal 1050 for stable operation of the system. At this time, the minimum duty rate is greater than 0%, and the maximum duty rate is less than 100%. For example, the minimum duty rate may be set to 5%, and the maximum duty rate may be set to 90%. Accordingly, when the step-down circuit 1011 and the step-up circuit 1022 operate, the first signal 1040 and the second signal 1050 may have a duty rate within a range of 5% to 90%. In addition, the first signal 1040 and the second signal 1050 when the decompression circuit 1011 and the boost circuit 1022 are turned off may have a duty rate of 0%.

Meanwhile, the control of the decompression circuit 1011 and the boosting circuit 1022 is achieved by controlling the duty rates of the first signal 1040 and the second signal 1050. At this time, both the decompression circuit 1011 and the boost circuit 1022 have the same rate at which the output increases or decreases according to the duty rate. For example, when the duty rate is changed to a%, the changed a% is reflected in the output voltage as it is. In other words, if the decompression circuit 1011 operates with a duty rate of 50%, the input voltage becomes 1/2 of the output voltage. Also, if the boosting circuit 1022 operates with a duty rate of 50%, the input voltage is twice the output voltage. Accordingly, if the total duty rate that is the sum of the duty rate of the decompression circuit 1011 and the duty rate of the boost circuit 1022 is the same, the voltage output through the buck booster 900 becomes the same.

Therefore, in the embodiment, the duty rate of the first signal 1040 provided to the decompression circuit 1011 and the duty rate of the second signal 1022 provided to the boost circuit 1022 are not distinguished, respectively, and the total With the duty rate of the summed buck booster 900, it is possible to control the decompression circuit 1011 and the boosting circuit 1022, respectively.

In other words, the duty rate of the buck booster 900 is the sum of the duty rate of the first signal 1040 provided to the decompression circuit 1011 and the duty rate of the second signal 1022 provided to the boosting circuit 1022. Can be.

This will be described in more detail below.

Meanwhile, the first constant voltage circuit 1012 and the second constant voltage circuit 1021 may be configured to be applied with a constant voltage according to the input voltage V_in.

One end of the first constant voltage circuit 1012 may be connected to the output terminal of the decompression circuit 1011 and one end of the common inductor 1030, and the other end of the first constant voltage circuit 1012 may be connected to ground.

One end of the second constant voltage circuit 1012 may be connected to the output terminal of the buck booster 100, and the other end of the second constant voltage circuit 1012 may be connected to the other end of the common inductor 1030 and one end of the boosting circuit 1022. .

11 is an equivalent circuit diagram of a switch provided in a buck booster according to an embodiment.

The decompression circuit 1011 and the boosting circuit 1022 of the buck booster 1000 illustrated in FIG. 10 may include a switch 1100 as illustrated in FIG. 11.

The decompression circuit 1011 and the step-up circuit 1022 may operate based on pulse width modulated signals input to the gates G and G, respectively.

When the voltage V_GS between the gate G of the switch 1100 and the sources S and S exceeds a predetermined breakdown voltage V_threshold, the current I_in applied to the drains D is directed to the source S And a voltage V_DS is applied between the drain D and the source S.

On the other hand, if the voltage between the gate G and the sources Source and S is equal to or less than a predetermined breakdown voltage V_threshold, the current I_in applied to the drains D is blocked from flowing in the source S direction. .

12 shows an equivalent circuit configuration when the buck booster operates in the buck mode according to an embodiment.

Hereinafter, the configuration of the buck mode equivalent circuit will be described in detail with reference to FIGS. 10 to 12.

As shown in FIG. 12, the buck mode equivalent circuit may include a decompression circuit 1011, a first constant voltage circuit 1012, a second constant voltage circuit 1021, and a common inductor 1030.

The decompression circuit 1011 may include a first CR series circuit 1110 and first switches Q1 and 1150 and a fifth resistor 1191.

Here, the first switch 1150 may be in the form of the switch 1100 illustrated in FIG. 11, but is not limited thereto.

The first CR series circuit 1110 includes a first capacitor C1 and a first resistor R1 connected in series, and both ends of the first CR series circuit 1110 are drain D of the first switch 1150, respectively. ) And the source (D).

The fifth resistors R5 and 1191 may be connected to the gate G and the source S of the first switch 1150.

The first constant voltage circuit 1012 may include a first diode 1170 and a second CR series circuit 1120.

The second CR series circuit 1120 includes a second capacitor C2 and a second resistor R2 connected in series, and both ends of the second CR series circuit 1120 may be connected to both ends of the first diode 1170. have.

The second constant voltage circuit 1021 may include a second diode 1180 and a third CR series circuit 1130.

The third CR series circuit 1130 includes a third capacitor C3 and a third resistor R3 connected in series, and both ends of the third CR series circuit 1130 may be connected to both ends of the second diode 1180. have.

The output of the decompression circuit 1011 and the input of the second constant voltage circuit 1021 may be interconnected through a common inductor 1030.

In addition, the first constant voltage circuit 1012 and the second constant voltage circuit 1021 may also be connected through a common inductor 1030.

The relationship between the input voltage V_in and the output voltage V_rail in the buck mode may be determined by Equation 1 below.

V_rail = V_in x D1 (Equation 1)

Here, D1 means the duty rate of the first signal 1040. For example, when D1 is 100%, the input voltage and the output voltage of the buck booster are the same, and when D1 is 50%, the output voltage V_rail of the buck booster may drop to half of the input voltage V_in.

13 shows an equivalent circuit configuration when the buck booster operates in the boost mode according to an embodiment.

Hereinafter, the configuration of the boost mode equivalent circuit will be described in detail with reference to FIGS. 10, 11, and 13.

13, the boost mode equivalent circuit may include a first constant voltage circuit 1012, a second constant voltage circuit 1021, a boosting circuit 1022, and a common inductor 1030.

Referring to FIG. 13, the boosting circuit 1022 may include a fourth CR series circuit 1140 and second switches Q2 and 1160 and a sixth resistor 1192.

Here, the second switch 1160 may be the same type of switch as the first switch 1150 of FIG. 12 described above. The second switch 1160 according to an embodiment may be configured as the switch 1100 illustrated in FIG. 11, but is not limited thereto.

The fourth CR series circuit 1140 includes a fourth capacitor C4 and a fourth resistor R4 connected in series, and both ends of the fourth CR series circuit 1140 are drain D of the second switch 1160, respectively. ) And the source (D).

The sixth resistor 1192 may be connected to the gate G and the source S of the second switch 1160.

The first constant voltage circuit 1012 may include a first diode 1170 and a second CR series circuit 1120.

The second CR series circuit 1120 includes a second capacitor C2 and a second resistor R2 connected in series, and both ends of the second CR series circuit 1120 may be connected to both ends of the first diode 1170. have.

The second constant voltage circuit 1021 may include a second diode 1180 and a third CR series circuit 1130.

The third CR series circuit 1130 includes a third capacitor C3 and a third resistor R3 connected in series, and both ends of the third CR series circuit 1130 may be connected to both ends of the second diode 1180. have.

The output of the boosting circuit 1022 and the input of the second constant voltage circuit 1021 may be interconnected.

In addition, the first constant voltage circuit 1012 and the second constant voltage circuit 1021 may also be connected through a common inductor 1030.

The relationship between the input voltage V_in and the output voltage V_rail in the boost mode may be determined by Equation 2 below.

V_rail = V_in/(1-D2) (Equation 2)

Here, D2 means the duty rate of the second signal 1050.

For example, when D2 is 0%, the input voltage and the output voltage of the buck booster are the same, and when D2 is 50%, the output voltage V_rail of the buck booster may be boosted to twice the input voltage V_in.

That is, as the value of D2 decreases, the intensity of the output voltage V_rail compared to the input voltage V_in may increase.

14 shows an equivalent circuit configuration when the buck booster operates in the buck-boost mode according to an embodiment.

Hereinafter, the configuration of the buck-boost mode equivalent circuit will be described in detail with reference to FIGS. 10 to 14.

As shown in FIG. 14, the buck-boost mode equivalent circuit includes a decompression circuit 1011, a first constant voltage circuit 1012, a second constant voltage circuit 1021, a boost circuit 1022, and a common inductor 1030. Can be configured.

Referring to FIG. 14, the decompression circuit 1011 may include a first CR series circuit 1110, first switches Q1 and 1150, and a fifth resistor 1191.

Here, the first switch 1150 may be in the form of the switch 1100 illustrated in FIG. 11, but is not limited thereto.

The first CR series circuit 1110 includes a first capacitor C1 and a first resistor R1 connected in series, and both ends of the first CR series circuit 1110 are drain D of the first switch 1150, respectively. ) And the source (D).

The fifth resistor 1191 may be connected to the gate G and the source S of the first switch 1150.

The boosting circuit 1022 may include a fourth CR series circuit 1140, second switches Q2 and 1160, and a sixth resistor 1192.

Here, the second switch 1160 may be the same type of switch as the first switch 1150 of FIG. 12 described above. The second switch 1160 according to an embodiment may be configured as the switch 1100 illustrated in FIG. 11, but is not limited thereto.

The fourth CR series circuit 1140 includes a fourth capacitor C4 and a fourth resistor R4 connected in series, and both ends of the fourth CR series circuit 1140 are drain D of the second switch 1160, respectively. ) And source (D).

The sixth resistor 1192 may be connected to the gate G and the source S of the second switch 1160.

The first constant voltage circuit 1012 may include a first diode 1170 and a second CR series circuit 1120.

The second CR series circuit 1120 includes a second capacitor C2 and a second resistor R2 connected in series, and both ends of the second CR series circuit 1120 may be connected to both ends of the first diode 1170. have.

The second constant voltage circuit 1021 may include a second diode 1180 and a third CR series circuit 1130.

The third CR series circuit 1130 includes a third capacitor C3 and a third resistor R3 connected in series, and both ends of the third CR series circuit 1130 may be connected to both ends of the second diode 1180. have.

The output of the decompression circuit 1011 and the input of the second constant voltage circuit 1021 may be interconnected through a common inductor 1030.

The step-down circuit 1011 and the step-up circuit 1022 may be connected through a common inductor 1030.

The boosting circuit 1022 and the second constant voltage circuit 1021 may be interconnected.

The first constant voltage circuit 1012 and the second constant voltage circuit 1021 may be connected through a common inductor 1030.

The relationship between the input voltage V_in and the output voltage V_rail in the buck-boost mode may be determined by Equation 3 below.

V_rail = V_in x D1 + V_in/(1-D2) (Equation 3)

Here, D1 is the duty rate of the first signal 1040, and D2 is the duty rate of the second signal 1050.

That is, the wireless power transmission apparatus according to the embodiment may control the values of D1 and D2 to control the output voltage V_rail of the buck booster 1000 to a specific voltage equal to or greater than the input voltage V_in.

15 is a flowchart of a method for determining a duty rate when designing a buck booster in a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 15, the wireless power transmitter may determine (or calculate) the duty rate of the buck booster 900 for each required power of the wireless power receiver (S1510). At this time, the range of the duty rate of the buck booster 900 includes the range of the duty rate of the first signal 1040 supplied to the decompression circuit 1011 and the second signal 1050 of the boost circuit 1022. Branches may be determined based on a range of duty rates.

For example, the minimum duty rate of the first signal 1040 may be set to 5%, and the maximum duty rate may be set to 90%. Also, the minimum duty rate of the second signal 1050 may be set to 5%, and the maximum duty rate may be set to 90%. In addition, when the decompression circuit 1011 and the boost circuit 1022 are turned off, the first signal 1040 and the second signal 1050 may have a duty rate of 0%. Accordingly, when the buck booster 900 operates, the duty rate of the buck booster 900 may have a range of 5% to 180%. In this case, the duty rate of the buck booster 900 may mean the sum of the duty rate of the first signal 1040 and the duty rate of the second signal 1050.

Then, the wireless power transmitter checks the maximum duty rate of the decompression circuit 1011 and the minimum duty rate of the step-up circuit 1022 (step 1520).

The reason for checking the maximum duty rate of the decompression circuit 1011 and the minimum duty rate of the step-up circuit 1022 is to determine an operation period of the buck-boost mode of the buck booster 900. At this time, the maximum duty rate of the decompression circuit 1011 may be 90%, and the minimum duty rate of the step-up circuit 1022 may be 5%.

Accordingly, the wireless power transmitter determines a buck mode period, a buck-boost mode period and a boost mode period based on the identified maximum duty rate of the decompression circuit 1011 and the minimum duty rate of the boost circuit 1022. Decide (S1530). That is, the duty rate of the buck booster 900 may range from 5% to 180%. The first section of the range of the duty rate of the buck booster 900 may be a buck mode section, the second section may be a buck-boost mode section, and the third section may be a boost mode section. At this time, in the embodiment, the start point for the second section located between the first section and the third section is determined based on the maximum duty rate of the decompression circuit 1011 and the minimum duty rate of the boosting circuit 1022. Do it. The start point for the second section may correspond to the end point of the first section.

In this case, in an embodiment, the starting point of the second section may be determined based on a point obtained by subtracting the minimum duty rate of the boosting circuit 1022 from the maximum duty rate of the decompression circuit 1011. For example, the maximum duty rate of the decompression circuit 1011 is 90%, the minimum duty rate of the step-up circuit 1022 is 5%, and thus the starting point of the second section is the buck booster 900. It may be a point where the duty rate is 85%. Alternatively, the first section operates up to the 85% point, and accordingly, the subsequent first duty rate 86% may be determined as the starting point of the second section.

Also, the end point of the second section may be determined based on the maximum duty rate of the decompression circuit 1011 and the minimum duty rate of the boost circuit 1022. Preferably, the end point of the second section may be a point obtained by adding the minimum duty rate of the boosting circuit 1022 to the maximum duty rate of the decompression circuit 1011. For example, the maximum duty rate of the decompression circuit 1011 is 90%, the minimum duty rate of the boost circuit 1022 is 5%, and thus the end point of the second section is the buck booster 900. It may be a point where the duty rate is 95%.

Accordingly, 86% to 95% of the duty rate range of the buck booster 900 is designated as a soft control section, and accordingly, the buck booster 900 operates in a buck-boost mode in the corresponding soft control section. Do it. In addition, the remaining ranges except for the soft control period may be defined as a buck mode control period and a boost mode control period.

The duty rate of the buck booster 900 may range from 5% to 180%. Also, a range of 86% to 95% of the range of the duty rate of the buck booster 900 may be determined as a buck-boost mode period. Also, a range of 5% to 85.9% of the range of the duty rate of the buck booster 900 may be determined as a buck mode period. Also, a range of 95.1% to 180% of the range of the duty rate of the buck booster 900 may be determined as a boost mode period.

Meanwhile, the buck mode period may be set up to a maximum duty rate point of the decompression circuit 1011. That is, the buck mode period can be set from 5% to 90%. And, the buck-boost mode period can be set from 90.1% to 95%. However, in this case, in the buck mode section, the first signal 1040 of the decompression circuit 1011 rises to a maximum duty rate, and accordingly, the first signal 1040 at the starting point of the buck-boost mode. The reduction of the duty rate is made. In this case, as the pressure-reducing circuit 1011 rises and decreases to the maximum duty rate, stress is generated in the switch, and thus, operational reliability may occur. Accordingly, in an embodiment, the buck mode period is terminated at a level lower than the maximum duty rate of the first signal 1040, and accordingly, the first signal is increased to the maximum duty rate in the buck-boost mode period.

Meanwhile, when each mode section for the duty rate of the buck booster 900 is determined as described above, the wireless power transmitter determines the duty rate of the first signal 1040 corresponding to the duty rate of the buck booster 900, and The duty rates of the two signals 1050 are respectively determined (S1540). In other words, the duty rate of the buck booster 900 is determined for each required power of the receiver, and the duty rates of the first and second signals according to the required power and the duty rate of the buck booster 900 are determined.

In conclusion, in the embodiment, the mode control section of the buck booster 900 is divided by the duty rate of the buck booster 900 expressed as the sum of the duty rate of the first signal 1040 and the second signal 1050. Based on this, the control of the boosting circuit 1022 and the decompression circuit 1011 is performed for each mode.

In this case, the duty rates of the buck booster 900 determined in the embodiment and the duty rates of the first and second signals corresponding thereto are shown in Table 1.

Of the first signal
Duty rate Of the second signal
Duty rate Buck booster (900)
Duty rate Operation mode 5 0 5 Buck mode 10 0 10 15 0 15 20 0 20 30 0 30 35 0 35 40 0 40 45 0 45 50 0 50 55 0 55 60 0 60 65 0 65 70 0 70 80 0 80 85 0 85 85.9 0 85.9 81 5 86 Buck-boost mode 82 5 87 83 5 88 84 5 89 85 5 90 86 5 91 87 5 92 88 5 93 89 5 94 90 5 95 90 5.1 95.1 Boost mode 90 10 100 90 15 105 90 20 110 90 25 115 90 30 120 90 35 125 90 40 130 90 50 140 90 60 150 90 70 160 90 80 170 90 90 180

In addition, according to the duty rate of the buck booster 900 according to Table 1, the range for the buck mode interval, the range for the buck-boost mode interval and the boost mode interval based on the entire range of the required power of the receiver Each of the ranges for can be set.

The range for the buck mode period is a range less than the first power as described above, the range for the boost mode period is a second power exceeding range, and the buck-boost mode period is a range from the first power or higher to the second power or lower. You can.

Thereafter, the wireless power transmitter stores the duty rates of the buck booster 900 determined for each of the required powers, and stores the duty rates of the first and second signals corresponding thereto (S1550).

That is, in the embodiment, in the operation design of the buck booster 900 provided in the wireless power transmitter, the concept of the agreement of the duty rates of the first signal and the second signal respectively, the total duty rate of the buck booster 900 By determining, it is possible to control the operation of the buck booster (900).

16 is a flowchart illustrating a method for controlling wireless power transmission in a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 16, the wireless power transmission apparatus may determine (or calculate) the required power of the receiver (S1610).

For example, the required power of the receiver may be dynamically determined (or calculated) based on information received from the corresponding wireless power receiver.

The wireless power transmitter according to an embodiment generates a power transfer contract based on receiver identification information and configuration information received in the identification and configuration steps 430 or 530 of FIG. 4 or 5, The required power of the receiver may be determined based on the generated power transmission contract.

Here, the receiver identification information may include manufacturer information, device identification information, version information, etc., but is not limited thereto.

Here, the configuration information may include, but is not limited to, the power class of the receiver, the maximum power expected at the output terminal of the rectifier of the receiver, and guaranteed power required by the receiver.

The wireless power transmission apparatus according to another embodiment may determine (or calculate) the required power of the receiver based on the renewed power transmission contract in the negotiation step 540 and/or the renegotiation step 570 of FIG. 5. have.

Here, the power transmission contract may include limit values of various parameters specifying power transmission to the corresponding receiver in the power transmission step 440 or 560 of FIG. 4 or 5. For example, the power transmission contract may include a lower power limit value (assured power) and/or an upper power limit value (maximum power) to be provided at a rectifier output terminal of the corresponding receiver, but is not limited thereto.

When the required power is determined, the wireless power transmitter selects the mode of the buck booster 900 based on the requested power (S1620). At this time, the mode of the buck booster 900 may include a first mode, a second mode, and a third mode.

That is, the mode of the buck booster 900 is a first mode in which the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched at a duty rate of 0%. And a second mode in which the first switch is switched between a second duty rate and a maximum duty rate based on the requested power, and the second switch is switched at a minimum duty rate, and a maximum duty based on the requested power. The first switch is switched at a rate, and may include a third mode for switching between a third duty rate and a maximum duty rate. The first mode is a buck mode, the second mode is a buck-boost mode, and the third mode is a boost mode.

When the required power is determined, the wireless power transmitter may select a mode of the buck booster 900 from the first to third modes based on the requested power.

Meanwhile, when the mode of the buck booster 900 is selected, the wireless power transmitter determines the duty rate of the first signal and the duty rate of the second signal in the selected mode (S1630).

That is, when the first mode is selected, the second signal has a fixed duty rate of 0%, and the duty rate of the first signal may vary between the minimum duty rate and the first duty rate.

In addition, when the second mode is selected, the duty rate of the first signal varies between the second duty rate and the maximum duty rate, and the duty rate of the second signal can be fixed at the minimum duty rate.

Further, when the third mode is selected, the duty rate of the first signal may be fixed at the maximum duty rate, and the duty rate of the second signal may vary between the minimum duty rate and the maximum duty rate.

Thereafter, the wireless power transmitter controls the buck booster 900 by supplying the first signal 1040 and the second signal 1050 corresponding to the determined duty rate to the decompression circuit 1011 and the boosting circuit 1022, respectively. (S1640).

17 is a flowchart illustrating a method for controlling wireless power transmission in a buck mode according to an embodiment.

Referring to FIG. 17, when the buck mode is determined according to the required power of the receiver, the duty rate of the first signal 1040 and the second signal 1050 in the buck mode corresponding to the requested power are determined. You can.

Then, the wireless power transmitter outputs the first signal 1040 having a duty rate in a first range according to the requested power (S1710). In this case, the first range may be between the first level and the second level. The first level may be determined based on a minimum duty rate of the first signal 1040. The second level may be a first duty rate. In addition, the first duty rate may correspond to a value obtained by subtracting the minimum duty rate of the second signal 1050 from the maximum duty rate of the first signal 1040.

Thereafter, the wireless power transmitter outputs a second signal 1050 in a'LOW' state (S1720). That is, the wireless power transmitter outputs a second signal 1050 having a duty rate of 0%.

Then, the wireless power transmitter controls the buck booster 900 based on the first signal 1040 and the second signal 1050 to output power required by the receiver (S1730).

18 is a flowchart illustrating a method for controlling wireless power transmission in a buck-boost mode according to an embodiment.

Referring to FIG. 18, when the buck-boost mode is selected according to the required power of the receiver, the duty rate of the first signal 1040 and the second signal 1050 corresponding to the requested power may be determined. To this end, the duty rate of the buck booster 900 may be preferentially determined. In addition, the duty rate of the first signal 1040 and the duty rate of the second signal 1050 may be determined based on the duty rate of the buck booster 900.

Then, the wireless power transmitter outputs the first signal 1040 having a duty rate in the second range according to the requested power (S1810). In this case, the second range may be between the third level and the fourth level. The third level may be a second duty rate. Also, the second duty rate may correspond to a level obtained by subtracting the minimum duty rate of the second signal 1050 from the maximum duty rate of the first signal 1040. In addition, the fourth level may be determined from a level obtained by adding the minimum duty rate of the second signal 1050 to the maximum duty rate of the first signal 1040.

Thereafter, the wireless power transmitter outputs the second signal 1050 fixed at the minimum duty rate (S1820). That is, the wireless power transmitter fixes and outputs the second signal 1050 having a duty rate of 5%.

Then, the wireless power transmitter controls the buck booster 900 based on the output first signal 1040 and second signal 1050 to output power required by the receiver (S1830).

19 is a flowchart illustrating a method for controlling wireless power transmission in a boost mode according to an embodiment.

Referring to FIG. 19, when the boost mode is determined according to the required power of the receiver, the duty rate of the first signal 1040 and the second signal 1050 in the determined boost mode may be determined.

Then, the wireless power transmitter outputs the first signal 1040 fixed at the maximum duty rate according to the requested power (S1910). That is, the wireless power transmitter fixes and outputs the first signal 1040 having a duty rate of 90%.

In addition, the wireless power transmitter outputs the second signal 1050 having a duty rate in the third range according to the requested power (S1920). In this case, the third range may be between the fifth level and the sixth level. The fifth level may be determined from the added level of the second signal 1050 at the maximum duty rate of the first signal 1040. That is, the fifth level may be determined based on the end point of the buck-boost mode. Also, the sixth level may be determined based on the maximum duty rate of the second signal 1050. That is, the sixth level may be a duty rate of 90%.

20A is a diagram illustrating a method of controlling an operation of a buck booster in a controller of a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 20A, when the required power of the receiver (or the transmission power of the transmitter) is less than the first reference power, the buck booster may operate in the buck mode. In addition, if the required power of the receiver (or the transmission power of the transmitter) is greater than or equal to the first reference power and less than or equal to the second reference power, the buck booster operates in a buck-boost mode, and if the second power is exceeded, the buck booster boosts. Mode.

In the buck mode, the level of the second signal applied to the second switch 1160 of the boost circuit 1022 of the above-described drawing may be maintained at a value of “”. That is, the duty rate of the second signal applied to the second switch 1160 in the buck mode may be 0%. Also, the first signal applied to the first switch 1150 of the decompression circuit 1011 may be a pulse width modulation signal having a constant duty rate. Here, the duty rate of the first signal may be between the minimum duty rate and the first duty rate. That is, the duty rate of the first signal in the buck mode may have a range between 5% and 85.9%, but is not limited thereto, and the duty rate of the first signal may be differently defined according to design purposes of those skilled in the art. have. That is, the minimum level of the duty rate of the first signal in the buck mode may be the minimum duty rate that the first signal can have. In addition, in the buck mode, the maximum level (first duty rate) of the duty rate of the first signal may be a level obtained by subtracting the minimum duty rate of the second signal from the maximum duty rate of the first signal.

In the buck-boost mode, both the first signal applied to the first switch 1150 of the decompression circuit 1011 and the second signal applied to the second switch 1160 of the boost circuit 1022 have a constant duty rate. It may be a pulse width modulated signal.

Here, the duty rate of the first signal may have a certain range. That is, the minimum level of the duty rate of the first signal in the buck-boost mode may be determined based on a level obtained by subtracting the minimum duty rate of the second signal from the maximum duty rate of the first signal. Also, the maximum level of the duty rate of the first signal in the buck-boost mode may be determined based on the level of the maximum duty rate of the first signal plus the minimum duty rate of the second signal.

Also, in the buck-boost mode, the duty rate of the second signal may be maintained at a specific level. Preferably, in the buck-boost mode, the duty rate of the second signal may maintain a minimum duty rate. Preferably, in the buck-boost mode, the duty rate of the second signal may be fixed at 5%.

In the boost mode, the level of the first signal applied to the first switch 1150 of the decompression circuit 1011 of the above-described figure may be maintained at the maximum duty rate. Preferably, in the boost mode, the level of the first signal applied to the first switch 1150 of the decompression circuit 1011 may be fixed at 90%. Also, the second signal applied to the second switch 1160 of the boost circuit 1022 in the boost mode may be a pulse width modulated signal having a constant duty rate.

Here, the duty rate of the second signal in the boost mode may have a range between the minimum duty rate and the maximum duty rate that the second signal can have.

In this case, the first reference power may be 5 watts (Watt) and the second reference power may be 75 watts (Watt), but it is not limited thereto, and it should be noted that different reference powers may be set according to design purposes of those skilled in the art do.

20B is a diagram illustrating a state transition between a first mode and a third mode according to an embodiment.

20B, the mode of the buck booster 900 in the embodiment may be determined according to the required power.

The mode of the buck booster 900 includes a first mode in which the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched at a duty rate of 0%, A second mode in which the first switch is switched between a second duty rate and a maximum duty rate based on the requested power and the second switch is switched at a minimum duty rate, and at a maximum duty rate based on the requested power A mode of the buck booster may be included among a third mode in which the first switch is switched and the second switch is switched between a minimum duty rate and a maximum duty rate.

Further, the mode of the buck booster 900 may be changed based on a control error (CE) packet.

For example, while the buck booster 900 is operating in the first mode, the duty rate D1 of the first switch may be changed between the minimum duty rate and the first duty rate. In addition, while the buck booster 900 is operating in the first mode, the duty rate of the second switch may be fixed at a duty rate of 0%.

Then, in the first mode, in the state in which the duty rate D1 of the first switch is increased up to the first duty rate, a power control signal (positive CE packet, which indicates an increase in required power (or an increase in transmit power)) When CE> 0) is received, the buck booster 900 may be changed from the first mode to the second mode (S2010).

 In addition, while the buck booster 900 is operating in the second mode, the duty rate D1 of the first switch may be changed between the first duty rate and the maximum duty rate according to the required power. In addition, while the buck booster 900 is operating in the second mode, the duty rate of the second switch may be fixed at a duty rate of 5% corresponding to the minimum duty rate.

Then, in the second mode, in a state in which the duty rate D1 of the first switch is reduced to the first duty rate, a power control signal (negative CE packet, indicating a decrease in required power (or a decrease in transmission power)) When CE<0) is received, the buck booster 900 may be changed from the second mode to the first mode (S2020).

Then, in the second mode, in a state in which the duty rate D1 of the first switch is increased to the maximum duty rate, a power control signal (positive CE packet, CE) indicating an increase in required power (or an increase in transmission power) When >0) is received, the buck booster 900 may be changed from the second mode to the third mode (S2030).

In addition, while the buck booster 900 is operating in the third mode, the duty rate D1 of the first switch may be fixed at 90%, which is the maximum duty rate, according to the required power. Further, the duty rate D2 of the second switch may be changed between the minimum duty rate and the maximum duty rate.

Then, in the third mode, the power control signal (negative CE packet, CE) indicating a decrease in the required power (or a decrease in transmission power) in a state in which the duty rate D2 of the second switch is reduced to the minimum duty rate. When <0) is received, the buck booster 900 may be changed from the third mode to the second mode (S2040).

21 is a diagram for explaining a method of controlling power transmission on a wireless power transmission system according to an embodiment.

Referring to FIG. 21, the wireless power receiver 2110 may receive AC power from the wireless power transmitter 2120 (S2111).

The wireless power receiver 2110 may determine an actual control point based on the received power strength (S2112).

Further, the wireless power receiver 2110 may select a desired control point (S2113).

Here, the request control point may be selected based on the type and power reception class of the corresponding wireless power receiver 2110, but is not limited thereto, and the request control point is dynamic through a predetermined negotiation procedure with the wireless power transmitter 2120. It may be selected as.

However, it should be noted that this is only an example, and the method for selecting the required control point may be different according to the design of a person skilled in the art.

The wireless power receiver 2110 may calculate a control error value based on the determined actual control point and the selected request control point (S2114).

The wireless power receiver 2110 may generate a control error packet including a control error value and transmit it to the wireless power transmitter 2120 (S2130).

For example, the wireless power transmitter 2120 may demodulate the in-band communication signal to identify the control error value included in the control error packet.

The wireless power transmitter 2120 may determine the actual transmit coil current by measuring the intensity of the current flowing through the transmit coil (S2121).

The wireless power transmitter 2120 may determine a new transmission coil current based on the control error value included in the control error packet and the determined actual transmission coil current (S2122).

The wireless power transmitter 2120 may control the actual transmit coil current to converge to the determined new transmit coil current (S2123).

At this time, the wireless power transmitter 2120 may determine a control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current. Here, the wireless power transmitter 2120 may calculate a new operation point according to the determined control method.

The wireless power transmitter 2120 may set the calculated new operation point (S2124).

The wireless power transmitter 2120 may convert power according to the set new operation point and transmit it to the wireless power receiver 2110 (S2125).

In the above-described embodiment of FIG. 21, the control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current may be determined by at least one of the following four control methods.

1) A voltage control method that controls the DC voltage input to the power converter, that is, the inverter operating voltage.

2) Phase control method to control the phase of the pulse width modulated signal applied to the inverter

3) Duty control method for controlling the duty rate of the pulse width modulated signal applied to the inverter

4) Frequency control method for controlling the frequency of the reference signal input to the power converter, that is, the operating frequency.

The wireless power transmitter 2120 according to the present embodiment may be designed such that only the voltage control method for controlling the DC voltage input to the power converter, that is, the inverter operating voltage, among the above four methods is applicable. It is not limited.

In this case, the wireless power transmitter 2120 may set a new operation point by controlling the duty rates of the first signal 940 and the second signal 950 applied to the buck-booster 900 of FIG. 9. . That is, the new operation point set in step 2124 may be a duty rate corresponding to each of the first signal 940 and the second signal 950, which are pulse width modulated signals.

As an example, assume that the wireless power transmitter 2120 performs charging by incrementally increasing the power intensity from the minimum transmittable power to the maximum transmittable power.

The wireless power transmitter 2120 sets the first signal 940 set according to the determined new transmission coil current while the second signal 950 is OFF—that is, with a duty rate of LOW or 0%. It can operate in a buck mode that controls the duty rate.

If the duty rate of the first signal 940 in the buck mode reaches the switch point, the wireless power transmitter 2120 decreases the duty rate of the first signal 940 by the minimum duty rate of the second signal 950 Accordingly, the duty rate of the second signal 950 is maintained at the minimum duty rate. That is, the wireless power transmitter 1920 may switch from the buck mode to the buck-boost mode.

In one embodiment, in the buck-boost mode, when the maximum duty rate of the first signal 950 is reached according to a new operation point setting, the wireless power transmitter 2120 converts the first signal 940 to the maximum duty rate. The second signal 950 may be controlled to increase from the minimum duty rate to the maximum duty rate.

As described above, the wireless power transmitter 2120 according to the embodiment may smoothly switch modes between the buck mode, the buck-boost mode and the boost mode according to the new operation point setting, through which the buck booster 900 ) Has the advantage of not only preventing sudden changes in output voltage, but also minimizing unnecessary power consumption and equipment damage.

22 is a view for explaining an operation point control method for controlling transmit power in a wireless power transmitter according to an embodiment.

22 is a view for explaining a method of controlling the first signal and the second signal applied to the buck-booster 900 according to the intensity of the current to be applied to the transmitting coil of the wireless power transmitter. In detail, FIG. 22 shows a method of dynamically controlling the duty rates of the first signal and the second signal according to the new transmission coil current determined in real time according to the power control algorithm of FIG. 21 described above.

In the above description, assume that the wireless power transmitter incrementally increases the current applied to the transmitting coil from the minimum current to the maximum current.

The wireless power transmitter may increase the duty rate of the first signal to the switching point until the determined new transmit coil current reaches the first current. That is, the switching point may be determined based on 85% obtained by subtracting 5%, which is the minimum duty rate of the second signal, from 90% which is the maximum duty rate of the first signal.

At this time, the second signal may be maintained in an OFF state, that is, a signal level is LOW or a duty rate is 0%. That is, the wireless power transmitter can turn off the second signal in the buck mode and increase the duty rate of the first signal to a value corresponding to the switching point.

When the determined new transmit coil current exceeds the first current, the wireless power transmitter may reduce the duty rate of the first signal by switching from buck mode to buck-boost mode. In other words, when the new transmit coil current exceeds the first current, the buck mode is switched to the buck-boost mode to adjust the duty rate of the first signal down by a certain value (i.e., the minimum duty rate of the second signal). It can then be incrementally increased again. In addition, the duty rate of the first signal may be incrementally increased from the down-adjusted value until the maximum duty rate of 90% is reached. At this time, the duty rate of the second signal may be maintained at the minimum duty rate. That is, the duty rate of the second signal can be maintained at 5%.

Here, when the duty rate of the first signal reaches the maximum duty rate, the intensity of the current flowing through the transmitting coil may reach the second current.

When the determined new transmit coil current exceeds the second current, the wireless power transmitter switches from buck-boost mode to boost mode to maintain the first signal at the maximum duty rate, and the duty rate of the second signal from the minimum duty rate to the maximum The duty rate can be increased incrementally.

The wireless power transmitter can incrementally increase the duty rate of the second signal until the current flowing in the transmitting coil reaches the maximum current.

Accordingly, the wireless power transmitter according to the present embodiment can smoothly switch between the buck mode, the buck-boost mode, and the boost mode according to the new operation point setting, through which the sudden output voltage change of the buck booster 900 Not only can it be prevented in advance, it also has the advantage of minimizing equipment damage due to unnecessary power consumption and rapid power changes.

The embodiment provides a buck mode, a boost mode, and a buck booster operating in a buck-boost mode between the buck mode and the boost mode, and accordingly, the buck mode, the boost mode and the buck-boost according to the power required by the wireless power receiver. The buck booster operates in one of the modes.

According to this, in the embodiment, frequent mode switching to a single operation mode such as a buck mode and a boost mode can be prevented, and accordingly, a stable system can be operated.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus capable of supplying various levels of power.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus excellent in efficiency and heat generation performance.

In addition, the embodiment has the advantage of providing a wireless power transmission method and apparatus capable of preventing electromagnetic interference in advance by having a half-bridge inverter operating at a fixed operating frequency.

In addition, the embodiment is advantageous in that it is possible to provide a wireless power transmission method and apparatus having a simple manufacturing cost and structure by controlling only the direct voltage applied to the inverter to control the transmission power.

Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered illustrative. The scope of the invention should be determined by rational interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Claims (12)

A buck booster that converts the first DC power to the second DC power and outputs the converted DC power;
An inverter that generates AC power based on the second DC power;
An antenna for wirelessly transmitting the AC power; And
It includes a controller for controlling the buck booster based on the required power of the receiver,
The buck booster,
A first switch disposed between the power line and the common inductor,
And a second switch disposed between the common inductor and the inverter,
The controller
Select the mode of the buck booster,
The mode of the buck booster
A first mode in which the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched at a duty rate of 0%;
A second mode in which the first switch is switched between a second duty rate and a maximum duty rate based on the required power, and the second switch is switched at a minimum duty rate;
A third mode in which the first switch is switched at a maximum duty rate based on the required power, and the second switch is switched between a minimum duty rate and a maximum duty rate,
The first duty rate,
Less than the maximum duty rate and greater than the second duty rate
Wireless power transmission device. According to claim 1,
And a demodulator demodulating the control signal received through the antenna,
The controller,
Selecting the mode of the buck booster based on the required power of the receiver included in the control signal, and determining the duty rate of the first switch and the second switch in the selected mode
Wireless power transmission device. According to claim 2,
The first switch,
It is connected to the decompression circuit for reducing and outputting the voltage of the first DC power,
The second switch,
It is connected to a boosting circuit that boosts and outputs the voltage of the first DC power.
Wireless power transmission device. According to claim 1,
The minimum duty rate is,
Greater than the duty rate of 0%,
The maximum duty rate is,
Less than 100% duty rate
Wireless power transmission device. The method of claim 4,
The first duty rate is,
Corresponding to the duty rate obtained by subtracting the minimum duty rate from the maximum duty rate
Wireless power transmission device. The method of claim 5,
The second duty rate is,
Corresponding to the duty rate obtained by subtracting the minimum duty rate from the first duty rate
Wireless power transmission device. According to claim 2,
The control unit,
Outputting a first signal corresponding to the determined duty rate of the first switch to the first switch,
Outputting a second signal corresponding to the determined duty rate of the second switch to the second switch
Wireless power transmission device. The method of claim 7,
The control unit,
Based on the required power, determine the sum of the duty rate of the first signal and the duty rate of the second signal,
The duty rate of the first signal and the duty rate of the second signal are respectively determined based on the determined sum.
Wireless power transmission device. Demodulating the control signal received through the antenna;
Determining a required power of a receiver based on the demodulated control signal;
Selecting a mode of the buck booster based on the determined required power; And
And controlling the buck booster based on the selected mode.
The buck booster,
A first switch disposed between the power line and the common inductor,
And a second switch disposed between the common inductor and the inverter,
The buck booster mode,
A first mode in which the first switch is switched between a minimum duty rate and a first duty rate based on the required power, and the second switch is switched at a duty rate of 0%;
A second mode in which the first switch is switched between a second duty rate and a maximum duty rate based on the required power, and the second switch is switched at a minimum duty rate;
And including the third mode in which the first switch is switched at a maximum duty rate based on the required power, and the switched between a third duty rate and a maximum duty rate.
The first duty rate,
Less than the maximum duty rate and greater than the second duty rate
Wireless power transmission method. The method of claim 9,
The minimum duty rate is,
Greater than the duty rate of 0%,
The maximum duty rate is,
Less than 100% duty rate
Wireless power transmission method. The method of claim 10,
The first duty rate is,
Corresponding to the duty rate obtained by subtracting the minimum duty rate from the maximum duty rate
Wireless power transmission method. The method of claim 11,
The second duty rate is,
Corresponding to the duty rate obtained by subtracting the minimum duty rate from the first duty rate
Wireless power transmission method.

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