KR102154223B1 - Wireless power receiving device capable of controlling effective load resistance and effective load resistance control method - Google Patents

Abstract

A wireless power receiving apparatus capable of controlling an effective load resistance is disclosed.
According to an embodiment, an apparatus for receiving power wirelessly includes: a rectifier configured to generate a rectified voltage based on a magnetic field generated by the apparatus for transmitting power wirelessly; And a controller for transmitting a control signal for controlling a rectified phase of the rectifier to adjust the effective load resistance of the wireless power receiving device to the rectifier.

Description

Wireless power receiving device capable of effective load resistance control and effective load resistance control method {WIRELESS POWER RECEIVING DEVICE CAPABLE OF CONTROLLING EFFECTIVE LOAD RESISTANCE AND EFFECTIVE LOAD RESISTANCE CONTROL METHOD}

It relates to wireless power transmission, and is a method of achieving maximum wireless power transmission efficiency without communication between a wireless power transmission device and a wireless power reception device.

In recent years, as smart devices have become popular and the power use of devices has increased, users need to supply power to devices in spaces such as offices and cafes. Accordingly, a wireless power supply method has appeared in order to solve the inconvenience of the existing wired power supply method.

Conventionally, in wirelessly supplying power, there has been a method of maintaining the maximum efficiency of wireless power supply by controlling the characteristics of the DC/DC converter of the wireless power receiving device, but this method is within the operating range of the DC/DC converter. There was a difficulty in having the optimum efficiency and maintaining stable operation even though the DC/DC converter controls the characteristics. In addition, there was also a method in which the wireless power receiving device requested the necessary power through communication between the wireless power transmitting device and the wireless power receiving device, and the wireless power transmitting device controlled the transmission power. There is a disadvantage that a separate communication device is required.

Accordingly, a wireless power receiver for wireless power transmission is proposed that maintains maximum efficiency of wireless power transmission regardless of load fluctuations and does not require a communication process between the wireless power transmitter and the wireless power receiver.

In wireless power transmission, by controlling the effective load resistance of the wireless power receiving device using a controller included in the wireless power receiving device, the inductance and transmission distance of the resonator are limited and the optimal wireless power in the situation where the load changes. It provides a way to maintain transmission efficiency.

According to an embodiment, an apparatus for receiving power wirelessly includes: a rectifier configured to generate a rectified voltage based on a magnetic field generated by the apparatus for transmitting power wirelessly; And a controller for transmitting a control signal for controlling a rectified phase of the rectifier to adjust the effective load resistance of the wireless power receiving device to the rectifier.

The controller may identify a load voltage applied to the load of the wireless power receiver and a load current flowing through the load, and identify the effective load resistance using the load voltage and load current.

The controller identifies an optimum effective load resistance that enables the wireless power receiver to have maximum efficiency, determines an optimum rectification phase at which the effective load resistance is equal to the optimum effective load resistance, and sets the rectification phase to the optimum. A control signal adjusted to the rectified phase may be transmitted to the rectifier.

The optimum effective load resistance is a parasitic resistance of the wireless power transmission device, an inductance of a transmission resonator included in the wireless power transmission device, a parasitic resistance of the wireless power reception device, an inductance of a reception resonator included in the wireless power reception device, and It may be determined based on a coupling coefficient between the transmitting resonator and the receiving resonator.

The controller may determine an optimum rectified voltage at which the effective load resistance is equal to the optimum effective load resistance, and an optimum rectified phase for outputting the optimum rectified voltage from the rectifier.

An effective load resistance control method according to an embodiment includes the steps of: a wireless power receiving device identifying a rectified voltage generated by a rectifier using a magnetic field received from the wireless power transmitting device; Identifying an effective load resistance of the wireless power receiving device; In order to adjust the effective load resistance, it may include transmitting a control signal for controlling the rectified phase of the rectifier to the rectifier.

The identifying of the effective load resistance may include: identifying a load voltage applied to a load of the wireless power receiver and a load current flowing through the load; And identifying an effective load resistance applied to the wireless power receiving apparatus by using the load voltage and the load current.

Transmitting the control signal to the controller may include: identifying an optimum effective load resistance that enables the wireless power receiving device to have maximum efficiency; Determining an optimum rectified phase at which the effective load resistance is equal to the optimum effective load resistance; And transmitting a control signal for adjusting the rectified phase to the optimal rectified phase to the rectifier.

The optimum effective load resistance is a parasitic resistance of the wireless power transmission device, an inductance of a transmission resonator included in the wireless power transmission device, a parasitic resistance of the wireless power reception device, an inductance of a reception resonator included in the wireless power reception device, and It may be determined based on a coupling coefficient between the transmitting resonator and the receiving resonator.

The determining of the optimum rectified phase includes: determining an optimum rectified voltage at which the effective load resistance is equal to the optimum effective load resistance; And determining an optimum rectified phase for outputting the optimum rectified voltage from the rectifier.

According to an embodiment, in transmitting power wirelessly, by controlling the effective load resistance of the wireless power receiving device using a controller included in the wireless power receiving device, the inductance and transmission distance of the resonator are limited and the load is changed. Optimal wireless power transmission efficiency can be maintained under the circumstances.

1 is a diagram illustrating a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment.
2 is a flowchart illustrating a method of controlling an effective load resistance according to an exemplary embodiment.
3 is a diagram illustrating a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment in more detail.

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

1 is a diagram illustrating a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment.

The wireless power transmission apparatus 101 according to an embodiment may include an AC/DC converter 110, an inverter 120, and a transmission resonator 130. The AC/DC converter 110 may receive an AC signal and convert the received AC signal into a DC signal. In addition, the inverter 120 may receive the DC signal converted by the AC/DC converter 110 and generate an RF signal for wireless power transmission by using the received DC signal. In addition, the transmission resonator 130 may generate a magnetic field using an RF signal generated by the inverter 120.

The wireless power receiving apparatus 100 according to an embodiment may include a receiving resonator 140, a rectifier 150, a DC/DC converter 160, a load 170, and a controller 180.

The reception resonator 140 may generate an AC signal by using a magnetic field generated by the transmission resonator 130 of the wireless power transmission device 101 and transmit the generated AC signal to the rectifier 150.

The rectifier 150 may rectify the AC signal received from the receiving resonator into a DC signal using a Silicon Controlled Rectifier (SCR). Here, the rectifier 150 may control the turn-on timing of gate driving by delaying the phase of the SCR voltage to adjust the magnitude of the rectified voltage. In the present specification, the rectified phase may refer to the phase of the SCR voltage.

The DC/DC converter 160 converts the rectified DC signal to a DC level required by the load 170, and the load 170 may consume power received wirelessly.

The controller 180 may detect a DC signal rectified by the rectifier 150, that is, a rectified voltage, a load voltage applied to the load, and a load current flowing through the load. In addition, the controller 180 identifies the load using the detected load voltage and load current, and rectifies a control signal so that the effective load resistance of the wireless power receiving device 100 affected by the load becomes the optimum effective load resistance. Can be delivered to 150. In this case, the optimum effective load resistance is the effective load resistance having the maximum efficiency of wireless power transmission, and the effective load resistance can be controlled by adjusting the rectified voltage.

2 is a flowchart illustrating a method of controlling an effective load resistance according to an exemplary embodiment.

In step 200, controller 180 may identify the DC signal generated by rectifier 150.

More specifically, the controller 180 may detect the magnitude and phase of the rectified voltage generated for the rectifier 150. In this case, the rectified voltage detected by the controller 180 may be determined by a turn-on timing according to the gate driving of the SCR of the rectifier 150. That is, the rectifier 150 that receives the AC signal generated by the receiving resonator 140 rectifies the received AC signal to generate a DC signal. At this time, the DC signal is generated using the SCR of the rectifier 150. In doing so, the magnitude of the rectified voltage can be controlled by controlling the turn-on timing of gate driving by adjusting the phase of the SCR voltage.

In step 201, the controller 180 may identify a load voltage applied to the load 170 and a load current flowing through the load. In addition, the controller 180 may determine the value of the load 170 using the identified load voltage and load current. In addition, the effective load resistance of the wireless power receiving apparatus 100 may be identified by using the identified value of the load 170.

In step 202, the controller 180 may determine whether the effective load resistance is an optimal effective load having maximum efficiency in wireless power transmission.

More specifically, the controller 180 includes a wireless power transmission frequency, an inductance of the wireless power transmission device 101, a parasitic resistance, an inductance of the wireless power receiving device 100, a parasitic resistance, an effective load resistance, and a transmission resonator 130 The efficiency of wireless power transmission may be determined by using the coupling coefficient between the reception resonators 140. In this case, the controller 180 may determine an effective load resistance at which the efficiency of wireless power transmission is maximized as the optimum effective load resistance. In addition, the controller 180 may determine whether the effective load resistance of the wireless power receiving apparatus 100 is an optimum effective load resistance.

In step 203, the controller 180 may adjust the rectifying phase of the rectifier.

More specifically, the effective load resistance of the wireless power transmission device 100 is determined by the load resistance and the turn-on timing according to the gate driving of the SCR, and the turn-on timing may be determined by the rectified phase. The controller 180 may determine an optimum rectified voltage at which the wireless power receiving apparatus 100 has an optimum effective load resistance, and may determine an optimum rectified phase for outputting the optimum rectified voltage. In addition, the controller 180 may determine whether the rectified voltage identified in step 200 is an optimal rectified voltage. At this time, when the rectified voltage is greater or less than the optimal rectified voltage, the controller 180 controls the rectifier 150 to adjust the rectified phase of the rectifier 150 to the optimal rectified phase in order to adjust the magnitude of the rectified voltage. Can be passed on. The rectifier 150 may adjust the rectification phase according to a control signal from the controller 180.

3 is a diagram illustrating a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment in more detail.

Transmission parasitic resistance representing all parasitic resistance components appearing in the wireless power transmission device 101 according to an embodiment is R _tx , the inductance of the transmission resonator 130 is L _tx , and all parasitic resistances appearing in the wireless power reception device 100 The reception parasitic resistance is R _rx , the inductance of the reception resonator 140 is L _rx , and the coupling coefficient between the transmission resonator 130 and the reception resonator 140 is k.

In general, in a wireless power transmission apparatus, the size and transmission distance of the transmission resonator and the reception resonator are limited according to the size of the load and power consumption, and accordingly, the inductance of the transmission resonator and the inductance of the reception resonator are also limited.

For example, when a buck (BUCK) DC/DC converter is used as a DC/DC converter, the efficiency η of wireless power transmission in a situation where inductance and transmission distance are limited may be determined through Equation 1.

Here, f _t may be a wireless power transmission frequency.

The controller 180 is the inductance of the receiving parasitic resistance R _rx, receiving cavity 140 of the transmission parasitic resistance R _tx, transmission resonator 130 inductance L _tx, the wireless power receiving device 101 of the wireless power transmission apparatus (101) L _rx And an optimum effective load resistance R _{L _ eff _ opt} having a maximum value of the efficiency η of wireless power transmission through Equation 2 using the coupling coefficient k between the transmission resonator 130 and the reception resonator 140.

The effective load resistance R _{L _ eff} of the wireless power receiver 100 may be an equivalent resistance including the DC/DC converter 160 and the resistance R _L of the load 170 that consumes actual power. In this case, the effective load resistance R _{L_eff} may exhibit different transmission characteristics depending on the type of DC/DC converter used.

The effective load resistance R _{L _ eff} according to an embodiment may have a relationship between the resistance R _L of the load 170 and Equation 3.

In this case, D is a section in which the switch is turned on in the DC/DC converter, and may have an arbitrary value between 0 and 1.

And, according to the relationship of Equation 3, the rectified voltage V _rec and the load voltage V _L may have a relationship of Equation 4.

The controller 180 ultimately delivers a control signal to the rectifier 150 to satisfy Equation 5 in order to obtain the maximum efficiency of wireless power transmission in a given environment even if the load 170 changes and the load resistance R _L changes. can do.

That is, the controller 180 can transmit a control signal for controlling the rectified voltage V _rec input to the DC/DC converter to the rectifier 150 so that the wireless power receiver 100 has the maximum wireless power transmission efficiency. have. Further, the rectifier 150 adjusts the rectified phase based on the received control signal to adjust the voltage ratio between the rectified voltage V _rec and the load voltage V _L , so that the effective load resistance R _{L _ eff} is the optimum effective load resistance R _{L _ eff} It can be controlled to be the same as _{_opt} .

The controller 180 may periodically measure the load through the load voltage V _L and the load periodically detected by the current I _L and the detected load voltage V _L and the load current I _L in the wireless power receiving device 100. In addition, a control signal may be transmitted to the rectifier 150 so that the effective load resistance identified using the measured load becomes an optimal effective load resistance set in advance according to the transmission environment. In addition, the rectifier 150 may control the rectified voltage V _rec by adjusting the rectified phase based on the received control signal.

By repeating this process according to a preset period, even if the load is changed, the effective load resistance of the wireless power receiving apparatus 100 can be maintained as the optimum effective load resistance, and accordingly, the efficiency of wireless power transmission can be maximized.

The equations described in this specification are only examples of the case of using a buck (BUCK) DC/DC converter, and the equation may be changed according to the converter used. However, the above-described operation can be applied to maintain the maximum efficiency of wireless power transmission regardless of the type of DC/DC converter.

Meanwhile, the method according to the present invention is written as a program that can be executed on a computer and can be implemented in various recording media such as magnetic storage media, optical reading media, and digital storage media.

Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations include a data processing device, e.g., a programmable processor, a computer, or a computer program product, i.e. an information carrier, e.g., machine-readable storage, for processing by or controlling the operation of a number of computers. It can be implemented as a computer program tangibly embodied in an apparatus (computer readable medium) or a radio signal. Computer programs, such as the computer program(s) described above, may be recorded in any type of programming language including compiled or interpreted languages, and as a standalone program or in a module, component, subroutine, or computing environment. It can be deployed in any form, including as other units suitable for the use of. A computer program can be deployed to be processed on one computer or multiple computers at one site, or to be distributed across multiple sites and interconnected by a communication network.

Processors suitable for processing a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. In general, the processor will receive instructions and data from read-only memory or random access memory or both. Elements of the computer may include at least one processor that executes instructions and one or more memory devices that store instructions and data. In general, a computer may include one or more mass storage devices, such as magnetic, magnetic-optical disks, or optical disks, to store data, receive data from, transmit data to, or both It may be combined so as to be. Information carriers suitable for embodying computer program instructions and data are, for example, semiconductor memory devices, for example, magnetic media such as hard disks, floppy disks and magnetic tapes, Compact Disk Read Only Memory (CD-ROM). ), Optical Media such as DVD (Digital Video Disk), Magnetic-Optical Media such as Floptical Disk, ROM (Read Only Memory), RAM (RAM) , Random Access Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and the like. The processor and memory may be supplemented by or included in a special purpose logic circuit structure.

Further, the computer-readable medium may be any available medium that can be accessed by a computer, and may include both a computer storage medium and a transmission medium.

While this specification includes details of a number of specific implementations, these should not be construed as limiting to the scope of any invention or claim, but rather as a description of features that may be peculiar to a particular embodiment of a particular invention. It must be understood. Certain features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination. Furthermore, although features operate in a particular combination and may be initially described as so claimed, one or more features from a claimed combination may in some cases be excluded from the combination, and the claimed combination may be a subcombination. Or sub-combination variations.

Likewise, although operations are depicted in the drawings in a specific order, it should not be understood that such operations must be performed in that particular order or sequential order shown or that all illustrated operations must be performed in order to obtain a desired result. In certain cases, multitasking and parallel processing can be advantageous. In addition, separation of the various device components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and the program components and devices described are generally integrated together into a single software product or packaged in multiple software products. You should understand that you can.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are only presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is apparent to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention may be implemented.

100: wireless power receiving device
101: wireless power transmission device
110: AC/DC converter
120: inverter
130: transmitting resonator
140: receiving resonator
150: rectifier
160: DC/DC converter
170: load
180: controller

Claims (10)

A rectifier that generates a rectified voltage based on a magnetic field generated by the wireless power transmission device; And
A controller that detects the magnitude and phase of the rectified voltage generated by the rectifier, and transmits a control signal to the rectifier to control the phase and magnitude of the rectified voltage of the rectifier in order to adjust the effective load resistance of the wireless power receiver
Including,
The rectifier controls the magnitude of the rectified voltage by controlling a turn-on timing according to the gate driving of the rectifier by adjusting the phase of the rectified voltage,
The effective load resistance of the wireless power receiving device is determined by a load resistance of the wireless power receiving device and a turn-on time according to the gate driving of the rectifier,
The turn-on timing of the gate driving is controlled by delaying the phase of the SCR (Silicon Controlled Rectifier) voltage corresponding to the phase of the rectified voltage,
The effective load resistance is determined by a load resistance of the wireless power receiving device and an inverse proportional value of a section in which a switch is turned on in the DC/DC converter. The method of claim 1,
The controller,
Identifying a load voltage applied to the load of the wireless power receiving device and a load current flowing through the load,
To identify the effective load resistance using the load voltage and load current
Wireless power receiving device. The method of claim 1,
The controller,
Identifying the optimum effective load resistance so that the wireless power receiving device has the maximum efficiency,
Determining an optimum rectified phase at which the effective load resistance is equal to the optimum effective load resistance,
Transmitting a control signal for adjusting the rectified phase to the optimal rectified phase to the rectifier
Wireless power receiving device. The method of claim 3,
The optimum effective load resistance is,
Parasitic resistance of the wireless power transmission device, the inductance of the transmission resonator included in the wireless power transmission device, the parasitic resistance of the wireless power reception device, the inductance of the reception resonator included in the wireless power reception device, and the transmission resonator and the reception resonator Determined based on the inter-coupling coefficient
Wireless power receiving device. The method of claim 3,
The controller,
Determining an optimum rectified voltage at which the effective load resistance is equal to the optimum effective load resistance,
Determining the optimum rectified phase for outputting the optimum rectified voltage from the rectifier
Wireless power receiving device. Identifying, by the wireless power receiving apparatus, a rectified voltage generated by the rectifier using a magnetic field received from the wireless power transmitting apparatus;
Identifying an effective load resistance of the wireless power receiving device;
Detecting the magnitude and phase of the rectified voltage generated by the rectifier, and transmitting a control signal for controlling the magnitude and phase of the rectified voltage of the rectifier to adjust the effective load resistance to the rectifier
Including,
The rectifier controls the magnitude of the rectified voltage by controlling a turn-on timing according to the gate driving of the rectifier by adjusting the phase of the rectified voltage,
The effective load resistance of the wireless power receiving device is determined by a load resistance of the wireless power receiving device and a turn-on time according to the gate driving of the rectifier,
The turn-on timing of the gate driving is controlled by delaying the phase of the SCR (Silicon Controlled Rectifier) voltage corresponding to the phase of the rectified voltage,
The effective load resistance is determined by a load resistance of the wireless power receiving device and an inverse proportional value of a section in which a switch is turned on in a DC/DC converter. The method of claim 6,
The step of identifying the effective load resistance,
Identifying a load voltage applied to a load of the wireless power receiving device and a load current flowing through the load; And
Identifying an effective load resistance applied to the wireless power receiver using the load voltage and load current
Effective load resistance control method comprising a. The method of claim 6,
Transmitting the control signal to the rectifier,
Identifying an optimum effective load resistance that enables the wireless power receiving device to have maximum efficiency;
Determining an optimum rectified phase at which the effective load resistance is equal to the optimum effective load resistance; And
Transmitting a control signal for adjusting the rectified phase to the optimal rectified phase to the rectifier
Effective load resistance control method comprising a. The method of claim 8,
The optimum effective load resistance is,
Parasitic resistance of the wireless power transmission device, the inductance of the transmission resonator included in the wireless power transmission device, the parasitic resistance of the wireless power reception device, the inductance of the reception resonator included in the wireless power reception device, and the transmission resonator and the reception resonator Determined based on the inter-coupling coefficient
Effective load resistance control method. The method of claim 8,
The step of determining the optimal rectification phase,
Determining an optimum rectified voltage at which the effective load resistance is equal to the optimum effective load resistance; And
Determining an optimal rectified phase for outputting an optimal rectified voltage from the rectifier
Effective load resistance control method comprising a.

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