KR20150028133A - Apparatus for transmitting wireless power and apparatus for receiving wireless power and system for transferring wireless power and method for processing information - Google Patents

Abstract

A wireless power receiving apparatus comprises a receiving coil, a rectifying unit, a signal detection unit, a control unit, and a modulation unit. The receiving coil receives AC power from a wireless power transmitting apparatus. The rectifying unit rectifies the received AC power into DC power and delivers the DC power to a load terminal. The signal detection unit detects a signal from the rectifying unit. The control unit identifies a state of the load terminal based on the signal detected by the signal detection unit. The modulation unit is arranged between the receiving coil and the rectifying unit. The modulation unit is modulated by a control signal of the control unit. By the modulation of the modulation unit, information is provided from the receiving coil to a transmitting coil of the wireless power transmitting apparatus.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless power transmission apparatus, a wireless power reception apparatus, a wireless power transmission system,

Embodiments relate to wireless power transmission techniques.

Recently, wireless power transmission (wireless power transmission) or wireless energy transfer (wireless energy transfer) for transferring electric energy to a desired device has been actively researched and developed.

A transmitter for transmitting wireless power and a receiver for receiving transmitted wireless power may be provided to utilize the wireless power transmission technology.

On the other hand, if the wireless power is supplied indefinitely to the receiving end, the receiving end can be damaged.

Accordingly, a technology for grasping the degree of wireless power required by the receiving end and controlling the wireless power at the transmitting end is disclosed in the publication (KR 10-1253669).

However, in the open literature, in order to provide the status of the receiving end as data information, both the transmitting end and the receiving end must have a communication module and a transmitting part. Therefore, in the open literature, a communication module has to be additionally provided, so that the structure is complicated and the cost can be increased. In addition, in the open literature, there is a possibility of operation error because signals around the transmitter and the receiver are mixed in noise during data communication.

Embodiments provide a wireless power transmission apparatus, a wireless power reception apparatus, a wireless power transmission system, and an information processing method capable of improving information transmission efficiency.

Embodiments provide a wireless power transmission device, a wireless power reception device, a wireless power transmission system, and an information processing method capable of controlling power transmission.

Embodiments provide a wireless power transmission apparatus, a wireless power reception apparatus, a wireless power transmission system, and an information processing method that can simplify a structure.

Embodiments provide a wireless power transmission apparatus, a wireless power reception apparatus, a wireless power transmission system, and an information processing method that can reduce cost.

According to the embodiment, the wireless power receiving apparatus for transmitting the power received from the wireless power transmitting apparatus to the load station includes: a receiving coil for receiving the AC power from the wireless power transmitting apparatus; A rectifier for rectifying the received AC power to DC power and delivering the DC power to the lower stage; A signal detector for detecting a signal from the rectifier; A control unit for determining a state of the lower stage based on a signal detected from the signal detector; And a modulator arranged between the receiving coil and the rectifying section and modulated according to a control signal of the control section. Modulation of the modulating part provides information from the receiving coil to the transmitting coil of the wireless power transmitting device.

According to the embodiment, the radio power transmission apparatus for transmitting the power for supplying to the subordinate stage to the radio power reception apparatus includes: a transmission coil whose current is changed in response to a current change of the radio power reception apparatus; An information detector for detecting a change in current of the transmission coil; A controller for determining a state of the lower stage based on the signal detected by the information detector; And a power adjuster for adjusting power to be transmitted to the wireless power receiving apparatus under the control of the controller.

According to the embodiment, there is provided a wireless power transmission system for transmitting power from a wireless power transmission apparatus to a wireless power reception apparatus, the wireless power reception apparatus comprising: Receiving coil; A signal detector for detecting power supplied to the lower stage; A first control unit for controlling a current change of the receiving coil based on a signal detected from the signal detecting unit; And a modulator that is disposed between the receiving coil and the lower end and is modulated under the control of the first control unit to induce a change in current of the receiving coil, A transmission coil whose current is changed in response to the transmission coil; A second controller for determining a state of the lower stage based on a current change of the transmission coil; And a power adjuster for adjusting power to be transmitted to the wireless power receiver under the control of the second controller.

According to an embodiment, an information processing method includes receiving power transmitted by a transmitting coil of a wireless power transmitting apparatus in a receiving coil of a wireless power receiving apparatus; Determining a state of a lower stage based on the received power and changing a current of the receiving coil to reflect state information; Changing a current in response to a current change of the receiving coil in a transmitting coil of a wireless power transmission apparatus; Acquiring state information of the wireless power receiving apparatus based on a current change of the transmission coil; And adjusting power to be transmitted to the wireless power receiving apparatus based on the status information.

The embodiment can change the current of the receiving coil, detect the current change of the receiving coil in response to the current in the wireless power transmitting device, and grasp the state of the lower stage and requests of the wireless power receiving device.

Therefore, since the communication between the wireless power transmission device and the wireless power reception device can be performed without a separate communication module, the cost can be reduced and the configuration of the device can be simplified.

In addition, by using the currents of the transmission coil and the reception coil for transmitting and receiving electric power in the electromagnetic induction system or the resonance frequency system, no noise around the system is mixed and the demands of the wireless power reception apparatus are accurately grasped and corresponding responses are obtained So that the operation reliability can be improved.

Meanwhile, various other effects will be directly or implicitly disclosed in the detailed description according to the embodiments to be described later.

1 is a diagram for explaining a wireless power transmission system according to an embodiment.
2 is an equivalent circuit diagram of a transmission induction coil according to the embodiment.
3 is an equivalent circuit diagram of a power source and a wireless power transmission apparatus according to an embodiment.
4 is an equivalent circuit diagram of a wireless power receiving apparatus according to an embodiment.
5 is a block diagram illustrating a wireless power transmission system according to an embodiment.
6 is a diagram illustrating a method of transmitting power status information in a wireless power receiving apparatus according to an embodiment.
7A to 7C are views showing an example of a signal reflecting the power state information output from the controller of the wireless power receiving apparatus.
8A to 8C are diagrams illustrating another example of a signal reflecting power state information output from the controller of the wireless power receiving apparatus.
9 is a detailed view of an information detecting unit of a wireless power transmission apparatus according to an embodiment.
Figs. 10A to 10C are diagrams showing waveforms generated by the information detecting unit of Fig. 9; Fig.

In the description of the embodiment, in the case where it is described as being formed "above" or "below" each element, the upper or lower (lower) And that at least one further component is formed and arranged between the two components. Also, in the case of "upper (upper) or lower (lower)", it may include not only an upward direction but also a downward direction based on one component.

Before describing a wireless terminal holder, let us consider a system that reflects the overall concept of transmitting wireless power.

1 is a diagram for explaining a wireless power transmission system according to an embodiment.

Referring to FIG. 1, a wireless power transmission system according to an embodiment may include a power source 100, a wireless power transmission device 200, a wireless power reception device 300, and an access terminal 400.

In an embodiment, the power source 100 may be included in the wireless power transmission device 200, but is not limited thereto.

The wireless power transmission apparatus 200 may include a transmission induction coil 210 and a transmission resonance coil 220.

The wireless power receiving apparatus 300 may include a receiving resonant coil 310, a receiving induction coil 320, and a rectifying unit 330.

Both ends of the power source 100 may be connected to both ends of the transmission induction coil 210.

The transmission resonant coil 220 may be disposed at a certain distance from the transmission induction coil 210.

The reception resonant coil 310 may be disposed at a certain distance from the reception induction coil 320. [

Both ends of the reception induction coil 320 can be connected to both ends of the rectification part 330 and the lower end 400 can be connected to both ends of the rectification part 330. In the embodiment, the terminal 400 may be included in the wireless power receiving apparatus 300.

The power generated by the power source 100 is transmitted to the wireless power transmission apparatus 200 and the power transmitted to the wireless power transmission apparatus 200 is resonated with the wireless power transmission apparatus 200 by a resonance phenomenon, And the resonance frequency values can be transmitted to the same wireless power receiving apparatus 300.

More specifically, the power transmission process will be described below.

The power source 100 may generate and transmit AC power having a predetermined frequency to the wireless power transmission apparatus 200.

The transmission induction coil 210 and the transmission resonance coil 220 may be inductively coupled. That is, in the transmission induction coil 210, an AC current is generated by the AC power supplied from the power source 100, and the transmission resonance coil 220, which is physically spaced apart by the electromagnetic induction by the AC current, Can be induced.

Thereafter, the power transmitted to the transmission resonance coil 220 can be transmitted to the wireless power receiving apparatus 300 having the same resonance frequency by using the frequency resonance method with the wireless power transmission apparatus 200 by resonance.

Power can be transmitted by resonance between two LC circuits whose impedance is matched. Such resonance-based power transmission enables power transmission to be performed at a higher transmission efficiency to a greater extent than the power transmission by the electromagnetic induction method.

The reception resonant coil 310 can receive the electric power transmitted from the transmission resonant coil 220 using the frequency resonance method. An AC current can flow in the reception resonance coil 310 due to the received power and the power transmitted to the reception resonance coil 310 is transmitted to the reception induction coil 320 inductively coupled to the reception resonance coil 310 by electromagnetic induction, Lt; / RTI > The power transmitted to the reception induction coil 320 may be rectified through the rectifying unit 330 and transmitted to the loading stage 400.

The transmission resonance coil 220, the reception resonance coil 310 and the reception induction coil 320 may have any one of a spiral structure and a helical structure, , But need not be limited thereto.

The transmitting resonant coil 220 and the receiving resonant coil 310 may be resonantly coupled so as to transmit electric power at a resonant frequency.

The power transmission efficiency between the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 can be greatly improved due to the resonance coupling between the transmission resonance coil 220 and the reception resonance coil 310.

The above-mentioned wireless power transmission system explained the power transmission by the resonance frequency method.

The embodiment can be applied to power transmission by an electromagnetic induction method in addition to the resonance frequency method.

That is, in the embodiment, when the wireless power transmission system performs power transmission based on the electromagnetic induction, the transmission resonance coil 220 included in the wireless power transmission apparatus 200 and the reception The resonance coil 310 can be omitted.

In wireless power transmission, quality factor and coupling coefficient can have important meaning. That is, the power transmission efficiency can be proportional to the quality index and the coupling coefficient, respectively. Therefore, as the value of at least one of the quality index and the coupling coefficient increases, the power transmission efficiency can be improved.

The quality factor may mean an index of energy that can be accumulated in the vicinity of the wireless power transmission apparatus 200 or the wireless power reception apparatus 300.

The quality factor may vary depending on the operating frequency (w), the shape of the coil, the dimensions, and the material. The quality index can be expressed by the following equation (1).

[Formula 1]

Q = w * L / R

L is the inductance of the coil, and R is the resistance corresponding to the amount of power loss occurring in the coil itself.

The quality factor can have a value from 0 to infinity. The larger the quality index, the higher the power transmission efficiency between the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 can be.

Coupling coefficient means the degree of magnetic coupling between the transmitting coil and the receiving coil, and ranges from 0 to 1.

The coupling coefficient may vary depending on the relative position or distance between the transmitting coil and the receiving coil.

2 is an equivalent circuit diagram of a transmission induction coil according to the embodiment.

As shown in FIG. 2, the transmission induction coil 210 may be constituted by an inductor L 1 and a capacitor C 1, thereby constituting a circuit having a proper inductance and a capacitance value.

The transmission induction coil 210 may be constituted by an equivalent circuit in which both ends of the inductor L1 are connected to both ends of the capacitor C1. That is, the transmission induction coil 210 may be composed of an equivalent circuit in which the inductor L1 and the capacitor C1 are connected in parallel.

The capacitor C1 may be a variable capacitor, and the impedance matching may be performed as the capacitance of the capacitor C1 is adjusted. The equivalent circuits of the transmission resonant coil 220, the reception resonant coil 310, and the reception induction coil 320 may also be the same as or similar to those shown in FIG. 2, but the invention is not limited thereto.

3 is an equivalent circuit diagram of a power source and a wireless power transmission apparatus according to an embodiment.

3, the transmission induction coil 210 and the transmission resonance coil 220 may include inductors L1 and L2 and capacitors C1 and C2 having inductance and capacitance values, respectively.

4 is an equivalent circuit diagram of a wireless power receiving apparatus according to an embodiment.

4, the reception resonant coil 310 and the reception induction coil 320 may include inductors L3 and L4 and capacitors C3 and C4 having inductance and capacitance values, respectively.

The rectifying unit 330 may convert the AC power received from the reception induction coil 320 into DC power and transmit the converted DC power to the loading stage 400.

Specifically, the rectification section 330 may include a rectifier and a smoothing circuit although not shown. In the embodiment, the rectifier may be a silicon rectifier, and may be equivalent to diode D1, as shown in FIG. 4, but this is not limiting.

The rectifier can convert the DC power to the AC power received from the reception induction coil 320.

The smoothing circuit can output smooth DC power by removing the AC component included in the DC power converted in the rectifier. In the embodiment, as the smoothing circuit, as shown in Fig. 4, a rectifying capacitor C5 may be used, but it need not be limited thereto.

The DC power delivered from the rectifying unit 330 may be a DC voltage or a DC current, but the present invention is not limited thereto.

The lower stage 400 may be any rechargeable battery or device requiring direct current power. For example, the lower stage 400 may mean a battery.

The wireless power receiving apparatus 300 may be mounted on an electronic apparatus requiring power such as a mobile phone, a notebook computer, and a mouse. Accordingly, the reception resonant coil 310 and the reception induction coil 320 may have shapes conforming to the shape of the electronic device.

Although the embodiment can exchange information between the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 in an in-band communication manner, the embodiment is not limited thereto.

In band communication may refer to a communication in which information is exchanged between a wireless power transmission apparatus 200 and a wireless power reception apparatus 300 using a signal having a frequency used for wireless power transmission. To this end, the wireless power receiving apparatus 300 may further include a switch and may not receive or receive the power transmitted from the wireless power transmitting apparatus 200 through the switching operation of the switch. Accordingly, the wireless power transmission apparatus 200 can detect the amount of power consumed in the wireless power transmission apparatus 200 and recognize the ON or OFF signal of the switch included in the wireless power reception apparatus 300. [

Specifically, the wireless power receiving apparatus 300 can change the amount of power consumed in the wireless power transmitting apparatus 200 by changing the amount of power received by the wireless power receiving apparatus 300 using a switch. The wireless power transmission apparatus 200 can detect the change in the consumed power and acquire the status information of the lower stage 400. [

In the embodiment, the state information of the load terminal 400 may include charge related state information, that is, information on the current charge amount and the charge amount transition of the load terminal 400. [ The lower stage 400 may be included in the wireless power receiving apparatus 300.

It may be called power state information instead of the state information of the lower stage 400. [ That is, since the embodiment grasps whether the power received from the wireless power transmission apparatus 200 is power that is insufficient for charging the loading stage 400 or is power or proper power, It is clear that it is within the technical spirit of the example.

The in-band communication method of the embodiment will be described later in detail.

5 is a block diagram illustrating a wireless power transmission system according to an embodiment.

Referring to FIG. 5, a wireless power transmission system according to an embodiment may include a power source 100, a wireless power transmission apparatus 200, a wireless power reception apparatus 300, and a load end station 400.

Since the power source 100 and the load terminal 400 have already been described in detail above, further explanation is omitted.

In an embodiment, the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 can exchange information using an in-band communication scheme. The in-band communication method of the embodiment does not need to have a transmitting module or a receiving module for separate data communication, and it is not necessary to use a separate communication frequency used for communication in these communication modules. Since the sending module and the receiving module are not used, the communication protocol between them need not be defined. Therefore, the in-band communication method of the embodiment remarkably reduces the cost and simplifies the structure of the device, thereby enabling miniaturization of the device.

The in-band communication method of the embodiment can, for example, artificially change the amount of received radio power in the wireless power receiving apparatus 300. For example, the reception of the wireless power amount may be periodically interrupted to change the wireless power amount. Such a change in the amount of radio power in the wireless power receiving apparatus 300 may also change the amount of wireless power of the wireless power transmitting apparatus 200 adjacent to the wireless power receiving apparatus 300. [ This is because the transmission coil 5 of the wireless power transmission apparatus 200 and the reception coil 11 of the wireless power reception apparatus 300 have an influence on each other.

For example, when the receiving coil 11 and the receiving end 400 of the wireless power receiving apparatus 300 are cut off, the current flowing through the receiving coil 11 of the wireless power receiving apparatus 300 changes, The current change of the transmission coil 11 of the wireless power transmission apparatus 200 induces a change in current of the transmission coil 5.

Thus, the wireless power transmission apparatus 200 can acquire information including the status of the wireless power reception apparatus 300 and the request by sensing the change in current of the transmission coil 5. In addition, the wireless power transmitting apparatus 200 can perform an operation corresponding to the request of the wireless power receiving apparatus 300 based on the obtained information.

The wireless power receiving apparatus 300 may include a receiving coil 11, a modulating unit 13, a rectifying unit 330, a signal detecting unit 17, and a control unit 19.

The receiving coil 11 can receive the radio power transmitted from the radio power transmitting apparatus 200. [ The wireless power receiving apparatus 300 of the embodiment can receive the wireless power of the wireless power transmitting apparatus 200 by an electromagnetic induction method or a frequency resonance method.

1, the transmission coil 5 of the wireless power transmission apparatus 200 includes a transmission induction coil 210 and a transmission resonance coil 220, and the wireless power transmission apparatus 200 300 may include a reception resonant coil 310 and a reception induction coil 320.

In the case of the inductive system, the transmitting resonant coil included in the wireless power transmitting apparatus 200 shown in FIG. 1 and the receiving resonant coil included in the wireless power receiving apparatus 300 may be omitted.

The radio power received at the receiving coil 11 is supplied to the rectifying section 330. [ The rectifying unit 330 may rectify the radio power and provide it to the lower stage 400.

The lower end 400 may be a charging element. The charging device may be mounted on an electronic device requiring charging. For example, the electronic device may be a wireless terminal capable of exchanging information by using wireless communication on the move. As the wireless terminal, a mobile device, a portable computer, a navigator, or the like can be used, but the present invention is not limited thereto. For example, the electronic device may include household appliances such as a television, a refrigerator, a washing machine, and the like.

The signal detector 17 can detect a signal output from the rectifier 330. The signal may be a voltage signal or a current signal, but this is not limiting. Although the signal is described as a voltage signal in the embodiment, it is not limited thereto. The signal detector 17 may provide the detected voltage signal to the controller 19.

The control unit 19 can control the wireless power receiving apparatus 300 as a whole. The control unit 19 can grasp the state information of the lower stage 400 based on the voltage signal detected from the signal detector 17. [ A preset reference voltage may be set in the control unit 19. [ According to the embodiment, the first and second reference voltages can be set in the control unit 19, but the present invention is not limited thereto. For example, the first reference voltage may be a minimum voltage capable of charging the negative terminal 400, and the second reference voltage may be a maximum voltage capable of safely charging the negative terminal 400. [

The control unit 19 compares the voltage signal detected from the signal detecting unit 17 with the first and second reference voltages to determine the state of the lower stage 400 according to the magnitude of the detection voltage and the first and second reference voltages have.

For example, when the detection voltage is smaller than the first reference voltage, the radio power output from the rectifier 330 is difficult to charge the lower stage 400. In this case, that is, in the case of power shortage, the radio power output from the rectifying section 330 needs to be increased.

For example, when the detection voltage is between the first reference voltage and the second reference voltage, the load 400 can be stably charged by the radio power output from the rectifier 330.

For example, if the detected voltage is greater than the second reference voltage, the load 400 may be overheated or destroyed by the radio power output from the rectifier 330. In this case, that is, when the power is excessive, the radio power output from the rectifier 330 needs to be reduced.

The control unit 19 can generate state information reflecting the state of the lower stage 400 by comparing the detected voltage with the first and second reference voltages.

The control unit 19 controls the modulation unit 13 based on the status information. The control unit 19 may generate a control signal based on the status information and provide the control signal to the modulation unit 13. [ The control signal may be a pulse width modulation (PWM) signal. The control signal may include a state of the lower stage 400 and request information for requesting adjustment of power in the wireless transmission device 200. [

The pulse width modulation signal can be varied. For example, the duty ratio of each period can be varied. For example, the duty ratio may be decreased for each period. That is, a pulse having a duty ratio of 100% is generated in the first period, a pulse having a duty ratio of 80% is generated in the second period, a pulse having a duty ratio of 60% is generated in the third period, In the fourth period, a pulse having a duty ratio of 40% can be generated.

Conversely, the duty ratio can be increased for each period. At this time, the rate of increase or decrease of the duty ratio may be constant or random. The parameters for such an increase rate or a decrease rate can be preset in the control section 19, but the present invention is not limited thereto.

The pulse width modulated signal may have a waveform as shown in Figs. 7 and 8, but it is not limited thereto.

The modulation section 13 can be modulated according to the control signal of the control section 19. [ Information can be provided from the receiving coil 11 to the transmitting coil 5 of the wireless power transmitting apparatus 200 by the modulation of the modulating unit 13.

As shown in Fig. 6, the modulating section 13 may include a switch 14. The switch 14 may be a semiconductor transistor, but it is not limited thereto. The semiconductor transistor may include one of a Bipolar Junction Transistor (BJT), a Metal Oxide Silicon Field Effect Transistor (MOSFET), and a Metal Insulating Silicon Field Effect Transistor (MISFET).

The control unit 19 may generate the pulse width modulation signal based on the status information and provide the pulse width modulation signal to the modulation unit 13. The pulse width modulated signal may be generated as shown in Figs. 7 and 8, but it is not limited thereto.

The pulse width modulated signal may comprise a plurality of high levels, i. E., A pulse and a plurality of low levels. The width of the high level pulse can be defined as the pulse width. The low level may have a lower level than the high level pulse, but it is not limited thereto.

In FIG. 7, each section is defined as one cycle, and the same pulse width modulation signal can be generated in each section. In FIG. 8, a plurality of sections are defined as one cycle, and the same pulse width modulation signal can be generated in each section.

Thus, even if an error occurs due to noise included in the pulse-width modulated signal in a specific period of time, by generating the same pulse-width modulated signal for each period, the pulse width modulation It is possible to prevent malfunction due to an error because the state of the lower stage 400 is grasped based on the signal.

As shown in FIG. 7A, when the state information is determined to be power shortage, a pulse width modulated signal including a plurality of pulses having an increasing pulse width in the first section can be generated. The same pulse width modulation signal as the first section can be generated in the second section. For example, each pulse width may be increased to 30%, 50%, 70% and 90%. In this manner, a pulse width modulated signal including a plurality of pulses having a pulse width that gradually increases with one cycle in each section can be generated.

As shown in FIG. 7B, when the state information is determined to be excessive, a pulse width modulated signal including a plurality of pulses having a gradually decreasing pulse width in the first section may be generated. The same pulse width modulation signal as that of the first section can be generated in the second section. For example, each pulse width may be reduced to 90%, 70%, 50%, and 30%. In this manner, a pulse width modulated signal can be generated that includes a plurality of pulses having a period of one period and a decreasing pulse width for each period.

As shown in Fig. 7C, when the state information is determined as the power holding, a pulse width modulated signal including a plurality of pulses having the same pulse width in both the first and second sections can be generated. Each pulse width may be equal to 50%. In this manner, a pulse width modulated signal including a plurality of pulses having one period and having the same pulse width for each section can be generated.

7A to 7C, the pulse widths are limited to four pulse widths (30%, 50%, 70%, and 90%).

As shown in Fig. 8A, when the state information is determined to be power shortage, a pulse width modulation signal including a plurality of pulses having the same pulse width is generated in each section, and the pulse widths of the sections may be different . For example, the pulse widths in the first to third sections may be increased to 30%, 60%, and 90%.

As shown in FIG. 8B, when the state information is determined to be excessively large, a pulse width modulation signal including a plurality of pulses having the same pulse width is generated in each section, and the pulse widths of the sections may be different . For example, the pulse widths in the first to third sections may be reduced to 90%, 60%, and 30%.

As shown in FIG. 8C, when the state information is judged to be power holding, a pulse width modulated signal including a plurality of pulses having the same pulse width is generated in each section, and the pulse widths of the sections may be all the same have. For example, the pulse widths in the first to third sections may all be equal to 50%.

The increase ratio of the pulse width described above may be expressed by a duty ratio. For example, increasing the pulse width can be explained as an increase in the duty ratio. In Fig. 7A, the duty ratio of each pulse can be increased to 30%, 50%, 70% and 90% within one cycle. In Fig. 7B, the duty ratio of each pulse can be reduced to 90%, 70%, 50% and 30% within one cycle. May be equal to 50% within one period of each pulse in FIG. 7C. 8A to 8C can similarly vary the duty ratio.

8A to 8C, the pulse width is limited to three pulse widths (50%, 70%, and 90%).

The modulation section 13, specifically the switch 14, can be switched and controlled in accordance with the pulse width modulation signal provided from the control section 19. [ That is, it can be turned on by the high level of the pulse width modulation signal, and can be turned off by the low level of the pulse width modulation signal. Thus, the switch 14 can be repeatedly turned on and off by a plurality of high levels and a plurality of low levels of the pulse width modulated signal.

The current flowing in the receiving coil 11 can be changed when the switch 14 is turned on and when the switch 14 is turned off. For example, the current flowing in the receiving coil 11 to which the switch 14 is turned off may be smaller than the current flowing in the receiving coil 11 when the switch 14 is turned on, but the present invention is not limited to this.

When the current flowing through the receiving coil 11 is periodically varied as described above, the magnetic field of the receiving coil 11 is changed. By the variation of the magnetic field, the transmission of the radio wave transmitting apparatus 200 adjacent to the receiving coil 11 The magnetic field of the coil 5 is also variable and the current flowing through the transmission coil 5 can also be varied by varying the magnetic field of the transmission coil 5. [ Therefore, by sensing the current of the transmission coil 5, the state of the loading stage 400 can be grasped. This will be described later.

The wireless power transmission apparatus 200 may include a power adjustment unit 3, a transmission coil 5, an information detection unit 7, and a control unit 9.

The transmitting coil 5 may transmit the power provided from the power source 100 to the receiving coil 11 of the wireless power receiving apparatus 300 using an electromagnetic induction method or a resonance frequency method.

The current and the magnetic field of the transmission coil 5 can also be changed in accordance with the change of the current and the magnetic field of the reception coil 11. [

The information detecting unit 7 can detect a change in current of the transmitting coil 5. [ 9, the information detecting section 7 may include the current detecting element 21, the current detecting section 23, the comparing section 25, and the ADC 27, but the present invention is not limited thereto.

The current detection element 21 is connected to the transmission coil 5 to allow the current of the transmission coil 5 to flow. One side of the current detection element 21 is connected to the transmission coil 5 and the other side of the current detection element 21 can be grounded, but this is not limited thereto.

The current detecting element 21 may be a resistance element, but the present invention is not limited thereto.

The current Id flowing through the current detecting element 21 may include a sawtooth ripple signal as shown in Fig. As described above, the ripple signal is supplied to the receiving coil 11 by the switching control of the switch 14 of the modulating unit 13 by the pulse width modulation signal provided from the control unit 19 of the wireless power receiving apparatus 300, It may be due to change. For example, the upper area of each tooth in the ripple signal corresponds to the high level of the pulse width modulated signal and the area between each tooth can correspond to the low level of the pulse width modulated signal, but this is not limiting.

In other words, the switching control by the switch 14 of the modulating unit 13 by the pulse width modulation signal generated by the control unit 19 of the wireless power receiving apparatus 300 changes the current of the receiving coil 11 The current of the transmission coil 5 of the wireless power transmission apparatus 200 may have a sawtooth shape in which the increase and decrease are repeated. At this time, the size of each tooth may be different, which may correspond to the pulse width or duty ratio of the pulse width modulation signal of the control unit 19 of the wireless power receiving apparatus 300.

The current detection unit 23 can sense the current signal Id flowing through the current detection element 21. [

The current sensing unit 23 may have first and second input terminals connected to the first and second nodes of the current detecting element 21. Accordingly, the current sensing unit 23 senses the current signal Id flowing through the current detecting element 21 disposed between the first and second input terminals, converts the current signal Id into a first voltage signal as shown in FIG. 10B, .

The first voltage signal may have a shape similar to the current signal. That is, the first voltage signal may also include a sawtooth-shaped ripple signal.

The comparator 25 has first and second input terminals, a first input terminal connected to an output terminal of the current sensing unit 23 and a second input terminal connected to a reference voltage input line.

The reference voltage Vref signal may be input to the comparator 25 through the second input terminal. The reference voltage Vref may be a DC voltage signal. The output signal of the current sensing unit 23, that is, the first voltage signal, may be input to the comparator 25 through the first input terminal.

The comparator 25 may generate a second voltage signal including a plurality of pulses of a square wave based on the first voltage signal from the current sensing unit 23 and the reference voltage signal as shown in FIG. 10C.

The reference voltage signal Vref may be determined between the top and bottom of the tooth of the first voltage signal.

The comparator 25 may process a portion of the first voltage signal that is larger than the reference voltage signal to a high level and process a portion of the first voltage signal that is smaller than the reference voltage signal to a low level. Accordingly, a second voltage signal including a high level higher than the reference voltage signal and a low level lower than the reference voltage signal can be generated. High level and low level can be defined as one cycle. A high level can be defined as a pulse.

The width of each pulse in the second voltage signal output from the comparator 25 may be different or the same. For example, the width of each pulse may be increasing or decreasing or equal to each other.

The second voltage signal output from the comparator 25 may be provided to the ADC 27. [

The analog-to-digital converter (ADC) 27 may convert the second voltage signal output from the comparator 25 into a digital voltage signal. The thus converted digital voltage signal can be provided to the control unit 9. [

As described above, it can be referred to as in-band communication that communication is performed using only a change in current of the reception coil 11 and the transmission coil 5 without a separate communication module.

Ultimately, the information detector 7 can provide the control unit 9 with information requested by the wireless power receiving apparatus 300 (hereinafter referred to as request information).

The control unit 9 can control the wireless power transmission apparatus 200 as a whole. In addition, the control unit 9 can grasp the request of the wireless power receiving apparatus 300 based on the request information provided from the information detecting unit 7. In other words, the control unit 9 can grasp the state of the lower stage 400 and the request of the wireless power receiving apparatus 300 based on the digital voltage signal provided from the information detecting unit 7, specifically, the ADC 27 .

For example, when the width of the pulse of the second voltage signal gradually increases, the controller 9 recognizes that the power supplied to the lower stage 400 is insufficient, while increasing the power in the wireless power receiving apparatus 300 You can see that you have requested to give.

The control unit 9 can control the power to be transmitted to the wireless power receiving apparatus 300 by controlling the power adjusting unit 3 based on the request of the wireless power receiving apparatus 300 identified by the information detecting unit 7. [

For example, when the wireless power receiving apparatus 300 requests to increase the power, the control unit 9 may control the power adjusting unit 3 to increase the power supplied from the power source 100. This increased power is provided to the transmitting coil 5 and the increased power in the transmitting coil 5 can be transmitted to the wireless power receiving apparatus 300 by the electromagnetic induction method or the resonance frequency method. The receiving coil 11 of the wireless power receiving apparatus 300 can receive the increased power and provide it to the loading stage 400 via the rectifying unit 330. [

For example, when the wireless power receiving apparatus 300 requests to reduce the power, the control unit 9 may control the power adjusting unit 3 to reduce the power supplied from the power source 100. This reduced power is provided to the transmitting coil 5 and reduced power in the transmitting coil 5 can be transmitted to the wireless power receiving apparatus 300 by electromagnetic induction or resonance frequency method. The receiving coil 11 of the wireless power receiving apparatus 300 may receive the reduced power and provide the reduced power to the lower stage 400 via the rectifying unit 330. [

In the embodiment, the power adjusting unit 3 is disposed between the power source 100 and the transmitting coil 5, but the present invention is not limited thereto. That is, the power adjustment unit 3 may be included in the power source 100. [ In this case, the power of the power source 100 can be adjusted and provided to the transmission coil 5 under the control of the control unit 9. [

While the preferred embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

3:
5: Transmission coil
7: Information detector
9, 19:
11: Receive coil
13: Modulation section
14: Switch
17:
21: Resistor element
23: Current sensing unit
25:
27: ADC
100: Power source
200: Wireless power transmitting device
210: transmission induction coil
220: transmission resonance coil
300: Wireless power receiving device
310: Receive resonant coil
320: reception induction coil
330: rectification part
400:

Claims (17)

A wireless power receiving apparatus for transmitting power received from a wireless power transmission apparatus to a load station,
A receiving coil for receiving AC power from the wireless power transmission device;
A rectifier for rectifying the received AC power to DC power and delivering the DC power to the lower stage;
A signal detector for detecting a signal from the rectifier;
A control unit for determining a state of the lower stage based on a signal detected from the signal detector; And
And a modulator disposed between the receiving coil and the rectifying section and modulated according to a control signal of the control section,
And information is provided from the receiving coil to the transmitting coil of the wireless power transmitting apparatus by modulation of the modulating unit. The method according to claim 1,
Wherein the information is transmitted in such a manner that a current of the receiving coil is changed by modulation of the modulating part and a current of the transmitting coil is changed in response to a current change of the receiving coil. The method according to claim 1,
Wherein the control signal is a pulse width modulated signal,
Wherein the pulse width modulated signal is variable. The method of claim 3,
Wherein the pulse width modulated signal is periodically generated repeatedly. 5. The method of claim 4,
Wherein the pulse-width modulated signal is varied from one section to another. 6. The method of claim 5,
And each of the sections has one period. 6. The method of claim 5,
Wherein the pulse width modulated signal is the same for each section and is variable for each section. 8. The method of claim 7,
Wherein at least two intervals have one period. The method of claim 3,
Wherein the duty ratio of the pulse width modulation signal is variable. The method according to claim 1,
And the modulator includes a switch. 11. The method of claim 10,
Wherein the switch is switched according to a control signal of the controller to change a current of the receiving coil. The method according to claim 1,
Wherein,
And compares the signal detected by the signal detector with a preset reference voltage to determine the state of the lower stage. The method according to claim 1,
The information includes:
The sub-stage status information and the power adjustment request information. A wireless power transmission apparatus for transmitting power to a wireless power receiving apparatus,
A transmitting coil whose current is changed in response to a current change of the wireless power receiving apparatus;
An information detector for detecting a change in current of the transmission coil;
A controller for determining a state of the lower stage based on the signal detected by the information detector; And
And a power adjuster for adjusting power to be transmitted to the wireless power receiving apparatus under the control of the controller. 15. The method of claim 14,
Wherein the information detecting unit comprises:
A current detector for detecting a current including a ripple signal in the transmission coil and converting the current into a first voltage signal;
A comparator for generating a second voltage signal having a rectangular wave pulse by using a first reference voltage as a ripple signal of the voltage signal detected by the current detector; And
And an analog-to-digital converter for converting the second voltage signal to a digital voltage signal,
And the control unit grasps the state of the lower stage based on the digital voltage signal. A wireless power transmission system for transmitting power from a wireless power transmission apparatus to a wireless power reception apparatus, the wireless power transmission system comprising:
The wireless power receiving apparatus includes:
A receiving coil for receiving the power and supplying the received power to the lower stage;
A signal detector for detecting power supplied to the lower stage;
A first control unit for controlling a current change of the receiving coil based on a signal detected from the signal detecting unit; And
And a modulator disposed between the receiving coil and the lower stage and modulated under the control of the first controller to induce a current change of the receiving coil,
The wireless power transmission apparatus comprising:
A transmission coil whose current is changed in response to a current change of the reception coil;
A second controller for determining a state of the lower stage based on a current change of the transmission coil; And
And a power adjuster that adjusts power transmitted to the wireless power receiving device under the control of the second controller. Receiving power transmitted by a transmit coil of a wireless power transmission apparatus in a receive coil of the wireless power receiving apparatus;
Determining a state of a lower stage based on the received power and changing a current of the receiving coil to reflect state information;
Changing a current in response to a current change of the receiving coil in a transmitting coil of a wireless power transmission apparatus;
Acquiring state information of the wireless power receiving apparatus based on a current change of the transmission coil; And
And adjusting power to be transmitted to the wireless power receiving apparatus based on the status information.

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