KR102146484B1 - Power generator, apparatus for transmitting wireless power and system for transferring wireless power - Google Patents

Abstract

The power generation device includes an AC power control unit for generating first to fourth AC power control signals according to the PWM control signal, and a transistor circuit unit having a full bridge structure, and a positive voltage in response to the first to fourth AC power control signals And a DC-AC converter for generating AC power including a negative voltage. The DC-AC converter generates a positive voltage in response to the first AC power control signal and the fourth AC power control signal, and generates a negative voltage in response to the second AC power control signal and the third AC power control signal. The duty ratio of the positive polarity voltage is determined by the polling time of the fourth AC power control signal, and the duty ratio of the negative polarity voltage is determined by the polling time of the third AC power control signal.

Description

Power generation device, wireless power transmission device, and wireless power transmission system {POWER GENERATOR, APPARATUS FOR TRANSMITTING WIRELESS POWER AND SYSTEM FOR TRANSFERRING WIRELESS POWER}

The embodiment relates to a wireless power transfer technology.

Wireless power transmission or wireless energy transfer, which wirelessly transfers electric energy to a desired device, started to use electric motors or transformers using the electromagnetic induction principle in the 1800s. A method of transmitting electrical energy by radiating the same electromagnetic wave has also been tried. Electric toothbrushes and some cordless razors that we commonly use are actually charged by the principle of electromagnetic induction. Electromagnetic induction refers to a phenomenon in which a voltage is induced and a current flows when a magnetic field is changed around a conductor. The electromagnetic induction method is rapidly commercialized mainly in small devices, but there is a problem with a short transmission distance of power.

Until now, energy transfer methods by wireless method include long-distance transmission technology using resonance and short-wavelength radio frequencies in addition to electromagnetic induction.

Recently, among such wireless power transmission technologies, energy transmission using resonance has been widely used.

In the wireless power transmission system using resonance, power is wirelessly transmitted through coils on the transmitting side and the receiving side, so that users can easily charge electronic devices such as portable devices.

However, there is a problem in that power loss occurs due to the current lost at the receiving side.

The embodiment provides a power generation device capable of minimizing wasted or consumed current.

The embodiment provides a power generation device capable of improving wireless power transmission efficiency.

The embodiment provides a wireless power transmission device including the power generation device.

The embodiment provides a wireless power transmission system including the wireless power transmission device.

According to an embodiment, the power generating apparatus includes: an AC power control unit for generating first to fourth AC power control signals; And a DC-AC converter for generating AC power including a positive voltage and a negative voltage in response to the first to fourth AC power control signals and including a transistor circuit unit having a full bridge structure. The DC-AC converter generates the positive voltage in response to the first AC power control signal and the fourth AC power control signal, and in response to the second AC power control signal and the third AC power control signal, the It produces a negative voltage.

According to an embodiment, the power generation device includes: an AC power control unit for generating first to fourth AC power control signals according to a Pulse Width Modulation (PWM) control signal; And a DC-AC converter for generating AC power including a positive voltage and a negative voltage in response to the first to fourth AC power control signals and including a transistor circuit unit having a full bridge structure. According to an embodiment, a wireless power transmission apparatus includes: the power generation apparatus; A transmission coil for transmitting power of the power generating device; And a controller for generating a PWM control signal for generating different power from the power generating device according to the state of the wireless power receiving device.

According to an embodiment, a wireless power transmission system includes: the wireless power transmission device; And a wireless power receiving device receiving the wireless power of the wireless power transmitting device and transmitting it to a load end.

The embodiment varies the AC power control signal for controlling the AC power generator according to the reception state of the wireless power receiver, and the duty of the AC voltage of the AC power output from the AC power generator in response to the change of the AC power control signal By controlling the ratio and controlling the amount of AC power, current loss can be prevented and power consumption can be prevented.

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

1 is a diagram illustrating a wireless power transmission system according to an embodiment.
2 is an equivalent circuit diagram of a transmission induction coil according to an 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 receiver according to an embodiment.
5 is a block diagram illustrating an apparatus for transmitting power wirelessly according to an embodiment.
6 is a block diagram illustrating an AC power generator of FIG. 5.
7 is a circuit diagram illustrating a DC-AC converter of FIG. 6.
8 is an exemplary diagram of a signal waveform diagram used in the AC power generator of FIG. 5.
9 is another exemplary diagram of a signal waveform diagram used in the AC power generation unit of FIG. 5.
FIG. 10 shows a magnitude according to a frequency component of AC power output from the AC power generator of FIG. 8.
FIG. 11 shows the magnitude of AC power output from the AC power generator of FIG. 9 according to a frequency component.
12 shows a current path when the first and fourth transistors are conducted in the DC-AC converter of FIG. 6.
13 is a view illustrating a current path when the second and third transistors are conducted in the DC-AC converter of FIG. 6.

In the description of the embodiment, in the case of being described as being formed on "upper (upper) or lower (lower)" of each component, the upper (upper) or lower (lower) two components are in direct contact with each other or It includes all of the one or more other components formed by being disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

1 is a diagram illustrating 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 a load terminal 400.

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

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

The wireless power receiving apparatus 300 may include a receiving resonance 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 predetermined distance from the transmission induction coil 210.

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

Both ends of the receiving induction coil 320 may be connected to both ends of the rectifying unit 330, and the load end 400 may be connected to both ends of the rectifying unit 330. In an embodiment, the load terminal 400 may be included in the wireless power receiving device 300.

The power generated by the power source 100 is transmitted to the wireless power transmission device 200, and the power delivered to the wireless power transmission device 200 resonates with the wireless power transmission device 200 by a resonance phenomenon. The resonance frequency value may be transmitted to the same wireless power receiving device 300.

Hereinafter, the power transmission process will be described in more detail.

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

The transmission induction coil 210 and the transmission resonance coil 220 may be inductively coupled. That is, the transmission induction coil 210 generates an AC current by the AC power supplied from the power source 100, and the transmission resonant coil 220 physically separated by the electromagnetic induction by this AC current Can be induced.

Thereafter, the power transmitted to the transmission resonant coil 220 may be transmitted to the wireless power receiver 300 having the same resonant frequency by using a frequency resonance method as the wireless power transmitter 200 by resonance.

Power may be transmitted between the two LC circuits whose impedance is matched by resonance. Power transmission by such resonance makes it possible to transmit power with higher transmission efficiency over a longer distance than power transmission by an electromagnetic induction method.

The reception resonance coil 310 may receive power transmitted from the transmission resonance coil 220 using a frequency resonance method. Due to the received power, an alternating current may flow through the receiving resonant coil 310, and the power delivered to the receiving resonant coil 310 is inductively coupled to the receiving resonant coil 310 by electromagnetic induction. Can be delivered to. The power delivered to the receiving induction coil 320 may be rectified through the rectifier 330 and transferred to the load terminal 400.

In the embodiment, the transmission induction coil 210, the transmission resonance coil 220, the reception resonance coil 310, and the reception induction coil 320 may have any one of a spiral structure or a helical structure. However, it is not necessary to be limited thereto.

The transmission resonance coil 220 and the reception resonance coil 310 may be resonantly coupled to transmit power at a resonance frequency.

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

In the above wireless power transmission system, power transmission using a resonance frequency method has been described.

In addition to the resonant frequency method, the embodiment may be applied to power transmission by an electromagnetic induction method.

That is, when the wireless power transmission system in the embodiment performs power transmission based on electromagnetic induction, the transmission resonant coil 220 included in the wireless power transmission device 200 and the reception included in the wireless power reception device 300 The resonance coil 310 may be omitted.

In wireless power transmission, a quality factor and a coupling coefficient may have important meanings. That is, the power transmission efficiency may have a proportional relationship with each of the quality index and the coupling coefficient. Therefore, as the value of at least one of the quality index and the coupling coefficient increases, the power transmission efficiency may be improved.

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

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

[Equation 1]

Q=w*L/R

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

The quality factor may have a value from 0 to infinity, and as the quality index increases, power transmission efficiency between the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 may be improved.

The coupling coefficient refers to the degree of magnetic coupling between the transmitting coil and the receiving coil and has a range of 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 an embodiment.

As shown in FIG. 2, the transmission induction coil 210 may be composed of an inductor L1 and a capacitor C1, and may be composed of a circuit having appropriate inductance and capacitance values by these.

The transmission induction coil 210 may be configured as 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 impedance matching may be performed as the capacitance of the capacitor C1 is adjusted. The equivalent circuit diagrams of the transmission resonance coil 220, the reception resonance coil 310, and the reception induction coil 320 may also be the same as or similar to those shown in FIG. 2, but are not limited thereto.

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

As shown in FIG. 3, the transmission induction coil 210 and the transmission resonant coil 220 may include inductors L1 and L2 and capacitors C1 and C2 each having an inductance value and a capacitance value.

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

As shown in FIG. 4, the reception resonant coil 310 and the reception induction coil 320 may be composed of inductors L3 and L4 and capacitors C3 and C4 each having an inductance value and a capacitance value.

The rectifier 330 may convert the AC power received from the receiving induction coil 320 into DC power and transfer the converted DC power to the load terminal 400.

Specifically, although not shown, the rectifier 330 may include a rectifier and a smoothing circuit. In the embodiment, a silicon rectifier may be used as the rectifier, and as shown in FIG. 4, it may be equivalent to a diode D1, but the embodiment is not limited thereto.

The rectifier may convert AC power received from the receiving induction coil 320 into DC power.

The smoothing circuit can output smooth DC power by removing the AC component included in the DC power converted by the rectifier. In the embodiment, as shown in FIG. 4, the rectifying capacitor C5 may be used as the smoothing circuit, but there is no need to be limited thereto.

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

The load end 400 may be any rechargeable battery or device that requires DC power. For example, the load end 400 may mean a battery.

The wireless power receiving device 300 may be installed in an electronic device requiring power, such as a mobile phone, a laptop computer, and a mouse. Accordingly, the receiving resonance coil 310 and the receiving induction coil 320 may have a shape suitable for the shape of the electronic device.

The apparatus 200 for transmitting power wirelessly may exchange information with the apparatus 300 for receiving power wirelessly through in-band or out-of-band communication.

In-band communication may refer to communication in which information is exchanged between the wireless power transmission apparatus 200 and the 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 or may not receive power transmitted from the wireless power transmitting apparatus 200 through a switching operation of the switch. Accordingly, the apparatus 200 for transmitting power wirelessly may detect an amount of power consumed by the apparatus 200 for transmitting power wirelessly and recognize an on or off signal of a switch included in the apparatus 300 for receiving power wirelessly.

Specifically, the wireless power receiving apparatus 300 may change the amount of power consumed by the wireless power transmitting apparatus 200 by changing the amount of power absorbed by the resistor using a resistance element and a switch. The apparatus 200 for transmitting power wirelessly may acquire state information of the load terminal 400 by sensing a change in consumed power. The switch and the resistive element can be connected in series. In an embodiment, the state information of the load terminal 400 may include information on a current charging amount and a change in charging amount of the load terminal 400. The load terminal 400 may be included in the wireless power receiving device 300.

More specifically, when the switch is opened, the power absorbed by the resistive element becomes zero, and the power consumed by the wireless power transmission apparatus 200 is also reduced.

When the switch is short-circuited, the power absorbed by the resistive element becomes greater than zero, and the power consumed by the wireless power transmission apparatus 200 increases. When the wireless power receiving apparatus repeats such an operation, the wireless power transmitting apparatus 200 may perform digital communication with the wireless power receiving apparatus 300 by detecting power consumed by the wireless power transmitting apparatus 200.

The apparatus 200 for transmitting power wirelessly may receive state information of the load terminal 400 according to the above operation and transmit power appropriate thereto.

Conversely, it is also possible to transmit state information of the wireless power transmission device 200 to the wireless power reception device 300 by providing a resistance element and a switch on the side of the wireless power transmission device 200. In the embodiment, the state information of the wireless power transmission device 200 is the maximum amount of power that can be transmitted by the wireless power transmission device 200, and the wireless power receiving device 300 providing power by the wireless power transmission device 200. It may include information on the number and the amount of available power of the wireless power transmission apparatus 200.

Next, out-of-band communication will be described.

Out-of-band communication refers to communication in which information necessary for power transmission is exchanged using a separate frequency band, not a resonant frequency band. An out-of-band communication module is mounted on each of the wireless power transmission apparatus 200 and the wireless power reception apparatus 300 so that information necessary for power transmission may be exchanged between the two. The out-of-band communication module may be mounted on the power source 100, but is not limited thereto. In the embodiment, the out-of-band communication module may use a short-range communication method such as Bluetooth, Zigbee, wireless LAN, and NFC (Near Field Communication), but is not limited thereto.

5 is a block diagram illustrating an apparatus for transmitting power wirelessly according to an embodiment.

1 and 5, a wireless power transmission apparatus 200 according to an embodiment may include an oscillator 230, an AC power generation unit 240, a control unit 235, and a transmission coil 205.

The oscillator 230 may generate a sine wave AC signal. The alternating current signal can have multiple periods. One cycle may include a first half cycle and a second half cycle. For example, the first half-period AC signal may have a positive sine wave. For example, the second half-cycle AC signal may have a negative sine wave.

In other words, the AC signal may be a signal that is periodically repeated with a positive sine wave and a negative sine wave as one cycle.

The AC signal of the oscillator 230 may be supplied to the AC power generator 240.

The AC power generator 240 may generate AC power from the power of the power source 100 based on the AC signal of the oscillator 230.

The transmit coil 205 may be a combination of the transmit induction coil 210 and the transmit resonant coil 220 or may be the transmit resonant coil 220 alone. That is, as shown in FIG. 1, the transmission coil 205 may include a transmission induction coil 210 and a transmission resonant coil 220 in the case of an electric machine induction method. The transmission coil 205 may be a transmission resonance coil 220 in the case of a resonance method.

The transmission coil 205 may transmit the AC power of the AC power generator 240 to the wireless power receiving device 300.

The control unit 235 may generally control the wireless power transmission apparatus 200. The control unit 235 may control the AC power generation unit 240.

The control unit 235 may control the AC power generation unit 240 according to the state of the wireless power receiving apparatus 300, that is, a charging state or a receiving state. For example, when higher wireless power is required for the wireless power receiving device 300, the controller 235 controls the AC power generating unit 240 to generate higher wireless power and transmitted to the wireless power receiving device 300 can do. For example, when a lower wireless power is required for the wireless power receiving device 300, the control unit 235 controls the AC power generator 240 to generate lower wireless power and transmitted to the wireless power receiving device 300 can do.

The state of the wireless power receiving apparatus 300 may be provided from the wireless power receiving apparatus 300 in response to a request of the wireless power transmitting apparatus 200. Alternatively, state information of the wireless power receiving device 300 may be provided from the wireless power receiving device 300 to the wireless power transmitting device 200 arbitrarily or at predetermined time intervals.

The controller 235 may supply the PWM control signal adjusted according to the state of the wireless power receiving device 300 to the AC power generating unit 240 based on the state information provided from the wireless power receiving device 300.

For example, the PWM control signal may be 6-bit binary data. For example, when the PWM control signal is 000001, in response to the PWM control signal, the AC power generator 240 may generate AC power having an AC voltage having a duty ratio of 50%. The AC power having an AC voltage of 50% duty ratio may be the maximum AC power that can be transmitted to the wireless power receiving apparatus 300, but is not limited thereto.

For example, when the PWM control signal is 000010, in response to the control signal, the AC power generator 240 may generate AC power having an AC voltage having a duty ratio of 40%.

For example, when the PWM control signal is 000011, in response to the control signal, the AC power generation unit 240 may generate AC power having an AC voltage having a duty ratio of 30%.

For example, when the PWM control signal is 000100, in response to the control signal, the AC power generation unit 240 may generate AC power having an AC voltage having a duty ratio of 20%.

For example, when the PWM control signal is 000101, in response to the control signal, the AC power generation unit 240 may generate AC power having an AC voltage having a duty ratio of 10%.

In addition, by setting the 6-bit binary data of the PWM control signal, AC power having an AC voltage may be generated in units of 5% duty ratio, 3% duty ratio, or 2% duty ratio, but is not limited thereto. .

As the duty ratio decreases, the size of the AC power may also decrease.

Accordingly, in the embodiment, in order to adjust the AC power for transmission to the wireless power receiving apparatus 300, instead of adjusting the amount of power of the power source 100, the control signal used to generate AC power is adjusted to control the AC power. By varying the size, current loss does not occur and power consumption is also blocked, thereby improving power transmission efficiency.

The AC power generation unit 240 may generate AC power to be transmitted to the wireless power receiving apparatus 300 based on the power provided from the power source 100.

The AC power generating unit 240 may generate AC power reflecting the state of the wireless power receiving device 300 under the control of the controller 235.

The AC power generator 240 may convert power provided from the power source 100 into AC power.

The AC power generator 240 may amplify the power provided from the power source 100.

The AC power generator 240 may convert the power provided from the power source 100 into AC power and then amplify the converted AC power.

In the drawing, the AC power generation unit 240 is included in the wireless power transmission apparatus 200, but the AC power generation unit 240 may be provided separately from the wireless power transmission apparatus 200. Alternatively, the AC power generation unit 240 may be included in the power source 100, but is not limited thereto.

6 is a block diagram illustrating an AC power generator of FIG. 5.

Referring to FIG. 6, the AC power generation unit 240 may include an AC power control unit 242 and a DC-AC conversion unit 244.

Although not shown, the AC power generation unit 240 may further include a DC-DC converter, but is not limited thereto. The DC-DC converter may convert the power of the power source 100 into DC power having a DC voltage and provide the DC power to the DC-AC converter 244.

The output voltage of the DC-DC converter may be, for example, a DC voltage of 12V, but is not limited thereto.

If a DC voltage of 12V is output from the power source 100, the DC-DC converter may be omitted.

As shown in FIG. 7, the DC-AC converter 244 may include a transistor circuit having a full-bridge structure.

For example, the transistor circuit unit having a full bridge structure may include first to fourth transistors T11, T12, T21, and T22.

For example, the first transistor T11 and the second transistor T12 may be connected in series between the fifth node n5 and the ground terminal. Also, for example, the third transistor T21 and the fourth transistor T22 may be connected in series between the fifth node n5 and the ground terminal.

The first transistor T11 and the third transistor T21 may be connected in parallel to the fifth node n5, and the second transistor T12 and the fourth transistor T22 may be connected in parallel to the ground terminal.

The fifth node n5 may be connected to the power source 100 or a DC-DC converter.

The first to fourth transistors T11, T12, T21, and T22 may be N-type MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistor), but are not limited thereto.

The first transistor T11 may be connected to the first node n1, the fifth node n5, and the sixth node n6. That is, the gate terminal of the first transistor T11 may be connected to the first node n1, the source terminal may be connected to the fifth node n5, and the drain terminal may be connected to the sixth node n6.

The second transistor T12 may be connected to the second node n2, the sixth node n6, and the ground terminal. That is, the gate terminal of the second transistor T12 may be connected to the second node n2, the source terminal may be connected to the sixth node n6, and the drain terminal may be connected to the ground terminal.

The third transistor T21 may be connected to the third node n3, the fifth node n5, and the seventh node n7. That is, the gate terminal of the third transistor T21 may be connected to the third node n3, the source terminal may be connected to the fifth node n5, and the drain terminal may be connected to the seventh node n7.

The fourth transistor T22 may be connected to the fourth node n4, the seventh node n7, and the ground terminal. That is, the gate terminal of the fourth transistor T22 may be connected to the fourth node n4, the source terminal may be connected to the seventh node n7, and the drain terminal may be connected to the ground terminal.

The first to fourth nodes n1, n2, n3, and n4 may be output terminals of the AC power controller 242. The AC power control unit 242 may generate first to fourth AC power control signals C11, C12, C21, and C22. For example, the first AC power control signal C11 may be output to the first node n1, and the second AC power control signal C12 may be output to the second node n2. For example, the third AC power control signal C21 may be output to the third node n3 and the fourth AC power control signal C22 may be output to the fourth node n4.

The sixth node n6 may be an output terminal of the first transistor T11 or the second transistor T12, and the seventh node n7 may be an output terminal of the third transistor T21 or the fourth transistor T22. have.

The first transistor T11 is conducted when the first AC power control signal C11 is at a high level and may be opened when the first AC power control signal C11 is at a low level. The second transistor T12 may be conducted when the second AC power control signal C12 is at a high level and may be opened when the second AC power control signal C12 is at a low level.

The third transistor T21 may be conducted when the third AC power control signal C21 is at a high level and may be opened when the third AC power control signal C21 is at a low level. The fourth transistor T22 may be turned on when the fourth AC power control signal C22 is at a high level and may be opened when the fourth AC power control signal C22 is at a low level.

8 and 9, the first to fourth AC power control signals C11, C12, C21, and C22 may vary according to the PWM control signal provided from the control unit 235. For example, the high level rising times (Tr11, Tr12, Tr21, Tr22) and polling times (Tf11, Tf12, Tf21, Tf22) of the first to fourth AC power control signals (C11, C12, C21, C22) may be different. have. In response to the first to fourth AC power control signals C11, C12, C21, and C22, the conduction times of the first to fourth transistors T11, T12, T21, and T22 are changed. The duty ratio Ton of the AC voltage Vout of the AC power supplied to 205 may vary.

In the embodiment, constant power in the wireless power receiver 300 by varying the duty ratio Ton of the AC voltage Vout of AC power according to the state of the wireless power receiver 300, for example, a charging state and/or a receiving state. Can be made to be received.

In addition, the embodiment may minimize power consumption by blocking a current that may be lost when generating AC power in the wireless power transmission apparatus 200.

8 shows waveform diagrams of first to fourth AC power control signals generated by a PWM control signal for generating AC power having an AC voltage having a duty ratio of 50%.

As shown in FIG. 8, the first to fourth AC power control signals C11, C12, C21, and C22 may be generated based on a clock signal Clock.

The clock signal (Clock) may be generated based on the AC signal of the oscillator 230 or may be generated by a separate means, but is not limited thereto.

The clock signal Clock may be generated by repeating a high level pulse and a low level pulse in one cycle.

For example, in the first AC power control signal C11, the rising time Tr11 for the high level is defined at a time delayed by a predetermined time from the rising time of the first high level pulse in the clock signal Clock. A falling time (Tf11) for the low level may be defined in the rising time of the second high level pulse.

For example, the high level section of the second AC power control signal C12 does not overlap with the high level section of the first AC power control signal C11. If the high level section of the first AC power control signal C11 and the high level section of the second AC power control signal C12 overlap, the first transistor T11 and the second transistor T12 are simultaneously connected. As a result, the output voltage of the power source 100 or the DC-DC converter is discharged to the ground terminal, so that the output voltage of the power source 100 or the DC-DC converter is not applied to the sixth node n6. ), power is not transmitted. Accordingly, between the polling time Tf11 of the first AC power control signal C11 and the rising time Tr12 of the second AC power control signal C12 or the rising time Tr11 of the first AC power control signal C11 A blank interval (T _PA ) in which high level intervals of the first and second AC power control signals C11 and C12 do not exist between the polling time Tf12 of the second AC power control signal C12 and the second AC power control signal C12 Can be defined.

The second AC power control signal C12 defines a rising time Tr12 for a high level at a time delayed for a predetermined time from a rising time of the second high level in the clock signal Clock, and the rising of the next third high level pulse. A polling time Tf12 for a low level in time may be defined.

For example, the high level section of the third AC power control signal C21 partially overlaps with the high level section of the first AC power control signal C11 and partially overlaps with the high level section of the second AC power control signal C12. I can. That is, the rising time Tr21 of the third AC power control signal C21 is faster than the polling time Tf11 of the first AC power control signal C11 and the polling time Tf21 of the third AC power control signal C21 Is later than the rising time Tr12 of the second AC power control signal C12.

For example, the high level section of the fourth AC power control signal C22 does not overlap with the high level section of the third AC power control signal C21. Similarly, if the high level section of the third AC power control signal C21 and the high level section of the fourth AC power control signal C22 overlap, the third transistor T21 and the fourth transistor T22 are simultaneously As a result of conduction, the output voltage of the power source 100 or the DC-DC converter is discharged to the ground terminal, and the output voltage of the power source 100 or the DC-DC converter is not applied to the seventh node n7. Power is not delivered to 205. Accordingly, between the polling time Tf21 of the third AC power control signal C21 and the rising time Tr22 of the fourth AC power control signal C22 or the rising time Tr21 of the third AC power control signal C21 A blank interval (T _AP ) in which the high level intervals of the third and fourth AC power control signals C21 and C22 do not exist between the polling time Tf22 of the fourth AC power control signal C22 and the fourth AC power control signal C22. Can be defined.

In addition, the high level section of the fourth AC power control signal C22 partially overlaps with the high level section of the first AC power control signal C11 and partially overlaps with the high level section of the second AC power control signal C12. I can. That is, the rising time Tr22 of the fourth AC power control signal C22 is faster than the polling time Tf12 of the second AC power control signal C12 and the rising time Tr11 of the first AC power control signal C11 Later than

The high level period of each of the first to fourth AC power control signals C11, C12, C21, and C22 may be defined within one period of the clock signal.

The polling time Tf21 of the third AC power control signal C21 and the polling time Tf22 of the fourth AC power control signal C22 may be adjusted according to the binary data value of the PWM control signal provided from the controller 235. .

As shown in FIG. 12, while the first transistor T11 and the fourth transistor T22 are conducting, AC power having a positive voltage may be supplied to the transmission coil 205.

The first AC power control signal C11 is applied to the first transistor T11 via the first node n1, and the fourth AC power control signal C22 is the fourth transistor via the fourth node n4. Can be applied with (T22).

It overlaps with the fourth AC power control signal C22 from the rising time Tr11 of the first AC power control signal C11, and this overlap ends at the polling time Tf22 of the fourth AC power control signal C22. I can. Accordingly, from the rising time Tr11 of the first AC power control signal C11 to the polling time Tf22 of the fourth AC power control signal C22, the high level of the first AC power control signal C11 and the fourth AC The high level of the power control signal C22 may overlap. While the high levels of the first and fourth AC power control signals C11 and C22 are overlapped, the first transistor T11 and the fourth transistor T22 are conducted to be transmitted from the power source 100 or the DC-DC converter. A current path is formed through the fifth node (n5), the first transistor (T11), the sixth node (n6), the transmission coil 205, the seventh node (n7) and the fourth transistor (T22) to the ground terminal. Thus, a positive voltage can be provided to the transmitting coil 205. Meanwhile, the polling time Tf22 of the fourth AC power control signal C22 may be earlier than the polling time Tf11 of the first AC power control signal C11. Therefore, since the fourth transistor T22 is open at least in a period between the polling time Tf22 of the fourth AC power control signal C22 and the polling time Tf11 of the first AC power control signal C11, the power From the source 100 or the DC-DC converter, the fifth node (n5), the first transistor (T11), the sixth node (n6), the transmission coil 205, the seventh node (n7), and the fourth transistor (T22). A current path is not formed to the ground terminal via ), so that a positive voltage is not provided to the transmission coil 205.

The high-level overlap section of the first and fourth AC power control signals C11 and C22 is a power transfer section and may be defined as a duty ratio Ton. The duty ratio (Ton) may be set to a maximum of 50% as a period in which power can be transmitted for one period, but is not limited thereto. For example, in the case of a 50% duty ratio (Ton), half of one cycle is capable of transmitting power and the other half of one cycle is not capable of transferring power.

As shown in FIG. 13, while the second transistor T12 and the third transistor T21 are conducting, AC power having a negative voltage may be supplied to the transmission coil 205.

The second AC power control signal C12 is applied to the second transistor T12 via the second node n2, and the third AC power control signal C21 is passed through the third node n3. It may be applied to the transistor T21.

It overlaps with the third AC power control signal C21 from the rising time Tr12 of the second AC power control signal C12, and this overlap ends at the polling time Tf21 of the third AC power control signal C21. Accordingly, from the rising time Tr12 of the second AC power control signal C12 to the polling time Tf21 of the third AC power control signal C21, the high level and the second AC power control signal C12 are 3 The high level of the AC power control signal C21 may overlap. While the high levels of the second and third AC power control signals C21 are overlapped, the second transistor T12 and the third transistor T21 are turned on, so that the fifth transistor is transmitted from the power source 100 or the DC-DC converter. A current path is formed to the ground terminal via the node n5, the third transistor T21, the seventh node n7, the transmission coil 205, the sixth node n6, and the second transistor T12, A negative voltage may be provided to the transmitting coil 205. Meanwhile, the polling time Tf21 of the third AC power control signal C21 may be earlier than the polling time Tf12 of the second AC power control signal C12. Therefore, since the third transistor T21 is opened at least in the period between the polling time Tf21 of the third AC power control signal C21 and the polling time Tf12 of the second AC power control signal C12, the power From the source 100 or the DC-DC converter, the fifth node (n5), the third transistor (T21), the seventh node (n7), the transmitting coil 205, the sixth node (n6) and the second transistor (T12). A current path is not formed to the ground terminal via ), so that a negative voltage is not provided to the transmission coil 205.

The high-level overlap section of the second and third AC power control signals C12 and C21 is a power transfer section and may be defined as a duty ratio Ton.

From FIG. 8, it can be seen that the duty ratio Ton is determined by the polling time Tf21 of the third AC power control signal C21 or the polling time Tf22 of the fourth AC power control signal C22. When the polling time Tf22 is delayed, the duty ratio Ton increases, and when the polling time Tf22 increases, the duty ratio Ton may decrease.

When the duty ratio (Ton) is increased, the AC power transmitted to the transmission coil 205 increases, and thus the wireless power received by the wireless power receiving apparatus 300 may also increase. If the duty ratio (Ton) is reduced, the AC power transmitted to the transmission coil 205 decreases, and thus the wireless power received by the wireless power receiving apparatus 300 may also be reduced.

In the embodiment, the first to fourth AC power control signals C11, C12, C21, from the AC power controller 242 according to the PWM control signal reflecting the increase or decrease of the AC power to be transmitted to the wireless power receiver 300. C22) is generated, and the duty ratio (Ton) of the AC voltage Vout output from the DC-AC converter 244 by the first to fourth AC power control signals C11, C12, C21, C22 is It is controlled, and the wireless power having the AC voltage Vout of the adjusted duty ratio Ton may be transmitted to the wireless power receiving apparatus 300 by the transmission coil 205.

9 shows waveform diagrams of first to fourth AC power control signals generated by a PWM control signal for generating AC power having an AC voltage having a duty ratio of 30%.

In FIG. 9, a method of generating the first to fourth AC power control signals C11, C12, C21, and C22 is the same as the above description related to FIG. 8.

The AC voltage Vout shown in FIG. 9 has a duty ratio Ton of 30% and is less than the duty ratio Ton of 50% of the AC voltage Vout shown in FIG. 8. In other words, the width of the positive voltage or negative voltage having a duty ratio Ton of 30% may be smaller than the width of the positive voltage or negative voltage having a duty ratio Ton of 50%.

In this way, the first to fourth AC power control signals C11, C12, C21, and C22 may be changed so that the duty of the AC voltage Vout is reduced to 30%. That is, the polling time Tf12 of the second AC power control signal C12 shown in FIG. 9 and the polling time Tf21 of the third AC power control signal C21 are the second AC power control signal shown in FIG. The polling time Tf12 of (C12) and the polling time Tf21 of the third AC power control signal C21 may be advanced.

Therefore, as the duty ratio Ton of the AC voltage Vout decreases, the polling time Tf12 of the second AC power control signal C12 and the polling time Tf21 of the third AC power control signal C21 increase. I can lose. For example, a polling time Tf12 of the second AC power control signal C12 and a polling time Tf21 of the third AC power control signal C21 at a duty ratio Ton of 20% rather than a duty ratio Ton of 30%. ) Can be accelerated.

FIG. 10 shows the magnitude according to the frequency component of AC power having an AC voltage of 50% duty ratio of FIG. 8, and FIG. 11 is a frequency component of AC power having an AC voltage of 30% duty ratio of FIG. 9 Show the size according to.

10 and 11 are experimental data using a simulation technique, the maximum voltage is 1V, but the size of wireless power actually used for power transmission may be, for example, 12V.

As shown in FIGS. 10 and 11, a voltage may be generated from a fundamental frequency component and a plurality of harmonic frequency components that are multiples of the fundamental frequency component. Among these, the voltage at the harmonic frequency component does not contribute to power to be transmitted to the wireless power receiving apparatus 300.

As shown in FIG. 10, in the case of a 50% duty ratio Ton, the voltage level at the fundamental frequency is 0.64V.

On the other hand, as shown in FIG. 11, when the duty ratio (Ton) is 30%, the voltage level at the fundamental frequency is 0.51V.

Therefore, it can be seen that as the duty ratio Ton decreases, the voltage level at the fundamental frequency decreases. As the voltage level decreases, the amount of power to be transmitted to the wireless power receiving apparatus 300 may also decrease.

The method according to the above-described embodiment may be produced as a program to be executed on a computer and stored in a computer-readable recording medium. Examples of computer-readable recording media include ROM, RAM, CD-ROM, and magnetic tape. , Floppy disks, optical data storage devices, and the like, and also include those implemented in the form of carrier waves (for example, transmission through the Internet).

The computer-readable recording medium is distributed over a computer system connected by a network, and computer-readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes and code segments for implementing the above-described method can be easily inferred by programmers in the technical field to which the embodiment belongs.

In addition, although preferred embodiments have been illustrated and described above, the technical spirit of the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications can be implemented by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

The wireless power receiver 300 according to the embodiment moves such as a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, etc. It can be mounted on the terminal.

However, it will be readily apparent to those skilled in the art that the configuration according to the embodiment may be applied to a fixed terminal such as a digital TV or a desktop computer, except when applicable only to a mobile terminal.

In an embodiment, the method of transmitting power by electromagnetic induction has a relatively low Q value and means tightly coupling, and the method of transmitting power by resonance has a relatively high Q value and a loose coupling. It can mean loosely coupling.

100: power source
200: wireless power transmission device
205: transmitting coil
210: transmitting induction coil
220: transmitting resonant coil
230: oscillator
235: control unit
240: AC power generation unit
242: AC power control unit
244: DC-AC converter
300: wireless power receiving device
310: receiving resonant coil
320: receiving induction coil
330: rectifier
400: load end
n1, n2, n3, n4, n5, n6, n7: nodes
T11, T12, T21, T22: transistor
Tr11, Tr12, Tr21, Tr22: Rising time
Tf11, Tf12, Tf21, Tf22: Polling time

Claims (13)

A power generating device that generates power for transmission to a wireless power receiving device,
An AC power control unit for generating first to fourth AC power control signals; And
A DC-AC converter for generating AC power including a positive voltage and a negative voltage in response to the first to fourth AC power control signals,
The DC-AC converter generates the positive voltage in response to the first AC power control signal and the fourth AC power control signal, and in response to the second AC power control signal and the third AC power control signal, the Power generation device that generates negative voltage. The method of claim 1,
The first to fourth AC power control signals are generated according to a PWM control signal,
The duty ratio of the positive voltage is determined by the polling time of the fourth AC power control signal,
The duty ratio of the negative voltage is determined by a polling time of the third AC power control signal. A power generating device that generates power for transmission to a wireless power receiving device,
An AC power control unit for generating first to fourth AC power control signals according to the PWM control signal; And
A power generating device comprising a DC-AC converter configured to generate AC power including a positive voltage and a negative voltage in response to the first to fourth AC power control signals. The method of claim 3,
The PWM control signal is a power generating device that is binary data reflecting the amount of power adjusted according to the state of the wireless power receiving device. The method of claim 3,
The power generation device in which the duty of each of the positive voltage and the negative voltage is changed by adjusting the polling time of each of the third AC power control signal and the fourth AC power control signal according to the PWM control signal. The method according to claim 1 or 3,
The DC-AC conversion unit,
A first transistor connected to a first node, a fifth node, and a sixth node to be connected to the first node in response to the first AC power control signal to supply the voltage of the fifth node to the sixth node;
A second transistor connected to a second node, the sixth node, and a ground terminal to be conducted in response to the second AC power control signal of the second node to supply the voltage of the sixth node to the ground terminal;
A third transistor connected to the third node, the fifth node, and the seventh node, and being connected to the third AC power control signal of the third node to supply the voltage of the fifth node to the seventh node ; And
A fourth transistor connected to a fourth node, the seventh node, and the ground terminal, and being conducted in response to the fourth AC power control signal of the fourth node to supply the voltage of the seventh node to the ground terminal. Power generation device comprising. The method according to claim 1 or 3,
The power generation device in which the polling time of the fourth AC power control signal is earlier than the polling time of the first AC power control signal. The method according to claim 1 or 3,
The power generation device in which the polling time of the third AC power control signal is earlier than the polling time of the second AC power control signal. The method of claim 2,
When the duty ratio is 50%, the maximum AC power is generated,
When the duty ratio is reduced, the magnitude of the AC power is reduced. The method of claim 3,
The state of the wireless power receiving device is a charging state or a receiving state,
The power generating device in which the binary data value of the PWM control signal is changed according to the state of the wireless power receiving device. The method of claim 10,
The power generation device in which the polling time of each of the third AC power control signal and the fourth AC power control signal is adjusted according to the binary data value. A wireless power transmission device for transmitting wireless power to a wireless power receiving device,
The power generation device according to claim 2 or 3;
A transmission coil for transmitting power of the power generating device; And
And a control unit for generating a PWM control signal for generating different power from the power generating device according to the state of the wireless power receiving device. The wireless power transmission apparatus according to claim 12 for generating wireless power; And
A wireless power transmission system comprising a wireless power receiving device receiving the wireless power of the wireless power transmitting device and transmitting the wireless power to a load end.

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