DRYER AND METHOD FOR CONTROLLING THE SAME

Abstract

A dryer includes: a chamber; a first electrode disposed on a first side of the chamber; a second electrode disposed on a second side of the chamber, the second side facing the first side; a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to the first electrode and the second electrode; an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode; and a frequency control circuit configured to adjust a frequency of a switching signal for turning the RF power supply on or off based on a change in a magnitude of the AC voltage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/KR2025/023098 designating the United States, filed on December 30, 2025, in the Korean Intellectual Property Receiving Office and claiming priority to Korean Patent Application No. 10-2025-0005565, filed on January 14, 2025, in the Korean Intellectual Property Office, the disclosures of each of which are incorporated by reference herein in their entireties.

BACKGROUND

Field

The disclosure relates to a dryer capable of drying an object through dielectric heating, and a method for controlling the dryer.

Description of Related Art

A dryer is a device capable of drying an object (e.g., clothing) by removing moisture contained in the object. Various types of drying devices capable of drying the object exist. For example, there is a dryer that supplies hot air into a drum that accommodates an object to dry the object. In the method of supplying hot air into the drum, heat is transferred from air having high heat to water having low heat, and thus, heat transfer efficiency is low and drying efficiency decreases accordingly. Furthermore, the hot air supplied into the drum is likely to damage the object.

In another example, there exists a dryer that is capable of drying an object through dielectric heating that uses radio frequency (RF). An existing dryer that uses the dielectric heating places the object between two flat electrodes arranged in parallel, and heats water contained in the object by producing an electric field between the two flat electrodes. However, the existing dryer using the dielectric heating generates an electric field of constant strength between two electrodes, and cannot adjust the strength of the electric field to reflect the impedance that changes as the object dries.

SUMMARY

Embodiments of the disclosure provide a dryer that may drive a radio frequency (RF) power supply using alternating current (AC) power supplied from an AC power source, and a method for controlling the dryer.

Embodiments of the disclosure provide a dryer that may minimize and/or reduce high-frequency noise by adjusting a switching frequency for controlling an RF power supply according to a magnitude of AC voltage, and a method for controlling the dryer.

According to an example embodiment, a dryer may include: a chamber; a first electrode disposed on a first side of the chamber; a second electrode disposed on a second side of the chamber, the second side facing the first side; a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to the first electrode and the second electrode; an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode; and a frequency control circuit configured to adjust a frequency of a switching signal for turning the RF power supply on or off based on a change in a magnitude of the AC voltage.

According to an example embodiment, in a method for controlling a dryer including a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to a first electrode and a second electrode, and an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode, the method may include: identifying, by a frequency control circuit, a change in a magnitude of the AC voltage; and adjusting, by the frequency control circuit, a frequency of a switching signal for turning the RF power supply on or off based on the change in the magnitude of the AC voltage.

According to the disclosure, a dryer and a method for controlling the same may drive an RF power supply using AC power supplied from an AC power source. The dryer and the method for controlling the same may not require a circuit structure and a control process for driving the RF power supply using direct current (DC) power. Accordingly, compared to existing technologies, the types, size, and manufacturing cost of the circuits included in the dryer may be reduced, and the circuit control method may be simplified.

The dryer and the method for controlling the same may minimize and/or reduce high-frequency noise by adjusting a switching frequency for controlling the RF power supply according to a magnitude of AC voltage.

The dryer and the method for controlling the same may enable adaptive impedance matching by adjusting a switching frequency according to an AC voltage, and may adaptively respond to changes in load impedance caused by movement of an object to be dried and a drying progress.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certain embodiments of the present disclosure will be more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating an example of a network system including various electronic devices according to various embodiments;

FIG. 2 is a perspective view of a dryer according to various embodiments;

FIG. 3 is a cross-sectional view of a dryer according to various embodiments;

FIG. 4 is a perspective view illustrating a layout of electrodes according to various embodiments;

FIG. 5 is a block diagram illustrating an example configuration of a dryer according to various embodiments;

FIG. 6 is a block diagram illustrating an example circuit system for a drying operation of a dryer according to various embodiments;

FIG. 7 and FIG. 8 are diagrams illustrating example circuit structures of the circuit system shown in FIG. 6 according to various embodiments;

FIG. 9 is a graph illustrating a relationship between a change in a magnitude of an alternating current (AC) voltage and a frequency of a switching signal for turning on or off a radio frequency (RF) power supply according to various embodiments;

FIG. 10 is a graph illustrating an example switching signal applied to an RF power supply based on a change in AC voltage magnitude according to various embodiments;

FIG. 11 is a graph illustrating an example operation of a frequency control circuit that determines a frequency of a switching signal applied to an RF power supply based on a change in AC voltage magnitude according to various embodiments;

FIG. 12 is a flowchart illustrating an example method for controlling a dryer according to various embodiments; and

FIG. 13 is a flowchart illustrating an example method for controlling the dryer described in FIG. 12 according to various embodiments.

DETAILED DESCRIPTION

Various example embodiments of the disclosure and terms used herein are not intended to limit the technical features described herein, and should be understood to include various modifications, equivalents, or substitutions.

In describing of the drawings, similar reference numerals may be used for similar or related elements.

The singular form of a noun corresponding to an item may include one or more of the items unless clearly indicated otherwise in a related context.

In the disclosure, phrases, such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B, or C” may include any one or all possible combinations of the items listed together in the corresponding phrase among the phrases.

Terms such as “1st”, “2nd”, “primary”, or “secondary” may be used simply to distinguish an element from other elements, without limiting the element in other aspects (e.g., importance or order).

When an element (e.g., a first element) is referred to as being “(functionally or communicatively) coupled” or “connected” to another element (e.g., a second element), the first element may be connected to the second element, directly (e.g., wired), wirelessly, or through a third element.

It will be understood that when the terms “includes”, “comprises”, “including”, and/or “comprising” are used in the disclosure, they specify the presence of the specified features, figures, steps, operations, components, members, or combinations thereof, but do not preclude the presence or addition of one or more other features, figures, steps, operations, components, members, or combinations thereof.

When a given element is referred to as being “connected to”, “coupled to”, “supported by” or “in contact with” another element, it is to be understood that it may be directly or indirectly connected to, coupled to, supported by, or in contact with the other element. When a given element is indirectly connected to, coupled to, supported by, or in contact with another element, it is to be understood that it may be connected to, coupled to, supported by, or in contact with the other element through a third element.

It will also be understood that when an element is referred to as being “on” another element, it may be directly on the other element or intervening elements may also be present.

As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Hereinafter, various example embodiments of the disclosure will be described in greater detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating an example of a network system including various electronic devices according to various embodiments.

Referring to FIG. 1, a home appliance 10 may include a communication module capable of communicating with another home appliance, a user device 2, or a server 3, a user interface that receives a user input or outputs information to a user, at least one processor that controls an operation of the home appliance 10, and at least one memory that stores a program for controlling the operation of the home appliance 10.

The home appliance 10 may be at least one of various types of home appliances. For example, as shown in the accompanying drawings, the home appliance 10 may include at least one of a refrigerator 11, a dishwasher 12, an electric range 13, an electric oven 14, an air conditioner 15, a clothes treating apparatus 16, a washing machine 17, a dryer 18, and/or a microwave oven 19.

However, the home appliance 10 is not limited to those shown in FIG. 1. For example, the home appliance 10 may include various types of appliances not shown in the drawings, such as a cleaning robot, a vacuum cleaner, a television, and the like. Furthermore, the aforementioned home appliances are by way of example only, and in addition to the aforementioned home appliances, other appliances connected to other home appliance, the user device 2, or the server 3 to perform operations described below may be included in the home appliance 10 according to an embodiment.

The server 3 may include a communication module (e.g., including communication circuitry) communicating with another server, the home appliance 10, or the user device 2, at least one processor that processes data received from another server, the home appliance 10, or the user device 2, and at least one memory that stores programs for processing data or processed data. The server 3 may be implemented as a variety of computing devices, such as a workstation, a cloud, a data drive, a data station, and the like. The server 3 may be implemented as one or more server physically or logically separated based on a function, detailed configuration of function, or data, and may transmit and receive data through communication between servers and process the transmitted and received data.

The server 3 may perform functions, such as managing a user account, registering the home appliance 10 in association with the user account, managing or controlling the registered home appliance 10, and the like. For example, a user may access the server 3 via the user device 2 and may create a user account. The user account may be identified by an identifier (ID) and a password set by the user. The server 3 may register the home appliance 10 with the user account according to a predetermined procedure. For example, the server 3 may link identification information of the home appliance 10 (e.g., a serial number or MAC address) to the user account to register, manage, and control the home appliance 10. The user device 2 may include a communication module capable of communicating with the server 3, a user interface that receives a user input or outputs information to a user, at least one processor that controls an operation of the user device 2, and at least one memory that stores a program for controlling the operation of the user device 2.

The user device 2 may be carried by a user, or placed in a user's home or office, or the like. The user device 2 may include a personal computer (PC), a terminal, a portable telephone, a smartphone, a handheld device, a wearable device, and the like, but is not limited thereto.

The memory of the user device 2 may store a program for controlling the home appliance 10, e.g. an application. The application may be sold installed on the user device 2, or may be downloaded from an external server for installation.

By running the application installed on the user device 2 by a user, the user may access the server 3, create a user account, and communicate with the server 3 based on the login user account to register the home appliance 10.

For example, by operating the home appliance 10 to allow the home appliance 10 to access the server 3 according to a procedure guided by the application installed on the user device 2, the server 3 may register the home appliance 10 with the user account by assigning the identification information (e.g., a serial number or a MAC address) of the home appliance 10 to the corresponding user account.

A user may control the home appliance 10 using the application installed on the user device 2. For example, by logging into a user account with the application installed on the user device 2, the home appliance 10 registered in the user account appears, and by inputting a control command for the home appliance 10, the control command may be delivered to the home appliance 10 via the server 3.

A network may include both a wired network and a wireless network. The wired network may include a cable network or a telephone network, and the wireless network may include any networks transmitting and receiving a signal via radio waves. The wired network and the wireless network may be interconnected.

The network may include a wide area network (WAN), such as the Internet, a local area network (LAN) formed around an access point (AP), and a short-range wireless network that does not use an AP. The short-range wireless network may include Bluetooth^TM (IEEE 802.15.1), Zigbee (IEEE 802.15.4), Wi-Fi Direct, near field communication (NFC), and Z-Wave, but is not limited thereto.

The AP may connect the home appliance 10 or the user device 2 to a WAN connected to the server 3. The home appliance 10 or the user device 2 may be connected to the server 3 via a WAN.

The AP may communicate with the home appliance 10 or the user device 2 using wireless communication, such as Wi-Fi^TM (IEEE 802.11), Bluetooth^TM (IEEE 802.15.1), Zigbee (IEEE 802.15.4), and the like, and access a WAN using wired communication, but is not limited thereto.

According to various embodiments, the home appliance 10 may be directly connected to the user device 2 or the server 3 without going through an AP.

The home appliance 10 may be connected to the user device 2 or the server 3 via a long-range wireless network or a short-range wireless network.

For example, the home appliance 10 may be connected to the user device 2 via a short-range wireless network (e.g., Wi-Fi Direct).

In another example, the home appliance 10 may be connected to the user device 2 or the server 3 via a WAN using a long-range wireless network (e.g., a cellular communication module).

In still another example, the home appliance 10 may access a WAN using wired communication, and may be connected to the user device 2 or the server 3 via a WAN.

When accessing a WAN using wired communication, the home appliance 10 may also act as an AP. Accordingly, the home appliance 10 may connect another home appliance 10 to a WAN to which the server 3 is connected. In addition, another home appliance 10 may connect the home appliance 10 to the WAN to which the server 3 is connected.

The home appliance 10 may transmit information about an operation or state to other home appliances, the user device 2, or the server 3 via the network. For example, the home appliance 10 may transmit information about an operation or state to other home appliances, the user device 2 or the server 3 upon receiving a request from the server 3, in response to an event in the home appliance 10, or periodically or in real time. Upon receiving the information about the operation or state from the home appliance 10, the server 3 may update the stored information about the operation or state of the home appliance 10 and transmit the updated information about the operation and state of the home appliance 10 to the user device 2 via the network. Updating the information may include various operations in which existing information is changed, such as adding new information to the existing information, replacing the existing information with new information, and the like.

The home appliance 10 may obtain various information from other home appliances, the user device 2, or the server 3, and may provide the obtained information to a user. For example, the home appliance 10 may obtain information related to a function of the home appliance 10 (e.g., recipes, washing instructions, etc.) from the server 3 and various environmental information (e.g., weather, temperature, humidity, etc.), and may output the obtained information via a user interface.

The home appliance 10 may operate in accordance with a control command received from other home appliances, the user device 2, or the server 3. For example, the home appliance 10 may operate in accordance with a control command received from the server 3, based on a prior authorization obtained from a user to operate in accordance with the control command of the server 3 even without a user input. The control command received from the server 3 may include a control command input by the user via the user device 2 or a control command based on preset conditions, but is not limited thereto.

The user device 2 may transmit information about a user to the home appliance 10 or the server 3 via the communication module. For example, the user device 2 may transmit information about a user's location, a user's health condition (e.g., state), a user's preference, a user's schedule, and the like to the server 3. The user device 2 may transmit information about the user to the server 3 based on the user's prior authorization.

The home appliance 10, the user device 2, or the server 3 may use techniques, such as artificial intelligence (AI) to determine a control command. For example, the server 3 may receive information about an operation or a state of the home appliance 10 or information about a user of the user device 2, process the received information using techniques, such as AI, and transmit a processing result or a control command to the home appliance 10 or the user device 2 based on the processing result.

A dryer 1 described below may correspond to the aforementioned home appliance 10.

FIG. 2 is a perspective view illustrating a dryer according to various embodiments.

Referring to FIG. 2, the dryer 1 may include a cabinet 1a that defines an exterior, and a drum 20 rotationally installed in the cabinet 1a. An interior of the drum 20 may form a chamber 20a that accommodates an object to be dried (hereinafter also referred to as “object”).

The cabinet 1a may be provided in a shape of substantially a hexahedron. The cabinet 1a may include a top cover 1b that provides a top portion of the cabinet 1a, a front cover 1c that provides a front portion thereof, and a base that provides a bottom portion thereof. For example, the front cover 1c, the top cover 1b, and the base, which form the cabinet 1a, may be separately provided and assembled together. In another example, some components (e.g., the front cover, the top cover and base) that forms the cabinet 1a may be integrally formed.

An inlet 31 through which to throw in or take out an object (e.g., clothing (not shown)) to or from the drum 20 may be provided at the front side of the cabinet 1a. The dryer 1 may include a door 50 configured to open or close the inlet 31 provided at the front cover 1c. A user may throw in or take out the object to or from the drum 20 through the inlet 31 after opening the door 50. When the inlet 31 is closed and the dryer 1 starts to operate, a door lock may lock the door 50.

A user interface 100 may be provided in an upper portion on the front surface of the cabinet 1a for interaction between the user and the dryer 1. The user interface 100 may obtain a user input and display various information about the dryer 1. A position of the user interface 100 may not be limited to the front surface. The user interface 100 may be provided in various position(s) on the dryer 1.

The user interface 100 may include a display. The user interface 100 may also include an input portion configured to obtain a user input relating to an operation of the dryer 1. The input portion may include a rotatable dial and various buttons. In addition, the user interface 100 may include various types of input portions and displays.

The display may be provided as various types of display panels. For example, the display may include a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, an organic LED (OLED) panel, or a micro LED panel. The display may include a touch screen to be used as an input device as well.

The display may display information input by the user or information to be provided for the user in various screens. The display may display information about an operation of the dryer 1 in at least one of an image or a text. The display may also display a graphic user interface (GUI) that enables control of the dryer 1. For example, the display may display a user interface element (UI element) such as an icon.

The input portion may transmit an electrical signal (e.g., voltage or current) corresponding to a user input to a controller 300 of the dryer 1. The input portion may include various buttons and/or a dial. For example, the input portion may include at least one of a power button to power on or off the dryer 1, a start/stop button to start or stop a drying operation, a drying mode button to select a drying mode, a temperature button to set a drying temperature, a time button to set a drying time, etc. These various buttons may be provided as mechanical buttons and/or touch buttons.

The dial included in the input portion may be rotatable. The UI elements displayed on the display may be sequentially shifted by turning the dial. The dryer 1 may perform drying according to a selected drying mode. The drying mode may include drying parameters, such as drying temperature and drying time. Other drying modes may be selected depending on a position of the object, a type of the object, and/or an amount of the object in the drum 20.

The dryer 1 may include a filter 40 detachably installed at the front cover 1c. The filter 40 may filter off a foreign substance such as lint that moves along with air circulating in the drum 20.

FIG. 3 is a cross-sectional view of a dryer according to various embodiments.

Referring to FIG. 3, the drum 20 of a cylindrical shape may be provided in the cabinet 1a. The drum 20 may accommodate and dry an object to be dried. The drum 20 may rotate by receiving power from a motor 72. The drum 20 may be provided in the cabinet 1a to rotate around a rotating axis arranged in almost parallel with the ground.

A lifter 21 may be provided on an inner circumferential surface of the drum 20 to lift the object while the drum 20 is rotating. An operation in which the object is lifted by the lifter 21 and then falls may be repeated according to a rotation speed of the drum 20. A roller 22 that supports the drum 20 to be smoothly rotated may be provided on an outer circumferential surface of the drum 20.

A driving device may be provided in a lower portion in the cabinet 1a. The driving device may be mounted on the base of the dryer 1. The driving device may include the motor 72, and a pulley 74 and a belt 75 configured to transfer power received from the motor 72 to the drum 20.

The pulley 74 may be connected to a rotation shaft 73, which is connected to the motor 72. When the rotation shaft 73 is rotated by the motor 72, the pulley 74 may be rotated along with the rotation shaft 73. The belt 75 may be installed to be wound on an outer surface of the pulley 74 and an outer surface of the drum 20. When the belt 75 is rotated by driving power of the motor 72, the drum 20 may be rotated along with the belt 75. The drum 20 may be rotated clockwise or counterclockwise.

A flow path 80 may be formed in the cabinet 1a and in the drum 20 in which air is circulated. The flow path 80 may include an air discharge path 81 in which air is discharged out of the drum 20 from inside the drum 20, and an air supply path 82 in which air is supplied into the drum 20.

The dryer 1 may include a discharge duct 60 that forms the air discharge path 81. The filter 40 may be disposed at an inlet 61 of the discharge duct 60. The discharge duct 60 may pass through the cabinet 1a, and an outlet 63 of the discharge duct 60 may be exposed to an outside of the cabinet 1a. The air flowing in through the inlet 61 of the discharge duct 60 may be filtered while passing the filter 40. The filter 40 may filter out a foreign substance such as lint contained in the air.

A fan 71 may be provided in the cabinet 1a to circulate the air. The air may flow into the discharge duct 60 from inside the drum 20 due to rotation of the fan 71. In addition, due to the rotation of the fan 71, air may be supplied into the drum 20 through the air supply path 83 and an air inlet 20b of the drum 20. The air supplied into the drum 20 may be used for drying the object.

The motor 72 may rotate not only the drum 20 but also the fan 71. The drum 20 and the fan 71 are shown as being driven by the single motor 72 in FIG. 3, but are not limited thereto. An extra fan motor (not shown) for driving the fan 71 may be included. The motor 72 may be directly connected to the drum 20 to rotate the drum 20. In a case where the motor 72 is directly connected to the drum 20, the pulley 74 and the belt 75 may be omitted.

A plurality of electrodes 90 may be provided between the cabinet 1a and the drum 20. For example, a first electrode 90a and a second electrode 90b may be provided between the cabinet 1a and the drum 20. The first electrode 90a and the second electrode 90b may be arranged along a circumference of the drum 20 to be spaced apart from each other. Two or more of each of the first electrode 90a and the second electrode 90b may be provided. The first electrode 90a and the second electrode 90b may be arranged to be separated even from the cabinet 1a and the drum 20.

Although the dryer 1 is shown as a drum-type dryer, the disclosure is not limited thereto. The dryer 1 may also be provided in a form having a storage space with shelves. The dryer 1 may not include the drum 20, and in this case, the position of the object placed between the first electrode 90a and the second electrode 90b may not change.

FIG. 4 is a perspective view illustrating an example layout of electrodes according to various embodiments.

Referring to FIG. 4, a plurality of electrodes 90 may be arranged along the circumference of the drum 20. The plurality of electrodes 90 may be spaced apart from each other. In the case of dryer 1 including the drum 20, each of the plurality of electrodes 90 may have a form of a curved plate. In the case of dryer 1 without the drum 20, each of the plurality of electrodes 90 may have a form of a flat plate.

The plurality of electrodes 90 may include the first electrode 90a and the second electrode 90b. The first electrode 90a and the second electrode 90b may be spaced apart from each other along the outer circumferential surface of the drum 20.

The plurality of electrodes 90 may be fixed between the cabinet 1a and the drum 20. The drum 20 is not connected to the electrodes 90. Accordingly, the electrodes 90 do not restrict the rotation of the drum 20. Furthermore, because the electrodes 90 are arranged along the circumference of the drum 20, electric fields may be produced in various areas in the drum 20. Accordingly, the dryer 1 according to the disclosure may produce the electric fields in the drum 20 through the electrodes 90, and dry the object while the drum 20 is rotating.

The number of electrodes 90 is shown as two in the drawings, but is not limited thereto. The dryer 1 may include two or more electrodes.

According to the disclosure, the dryer 1 includes a circuit structure capable of supplying power suitable for drying the object. When power is supplied to the electrodes 90, an electric field may be generated within the chamber 20a. The electric field generated in the drum 20 by the electrodes 90 may vibrate dielectrics (e.g., water molecules) contained in the object. When the dielectrics (e.g., water molecules) vibrate, dipole frictional heat may be generated, thereby heating the dielectrics. When the heated dielectrics evaporate, the object may be dried. The evaporated dielectrics may be discharged out of the drum 20 along with the air supplied into the drum 20.

FIG. 5 is a block diagram illustrating an example configuration of a dryer according to various embodiments.

Referring to FIG. 5, the dryer 1 may include a circuit system configured to perform a drying operation. For example, the dryer 1 may include a rectifier circuit 110, a radio frequency (RF) power supply 120, a frequency control circuit 130, an impedance matching circuit 140, and the electrodes 90. The dryer 1 may include the motor 72 for rotating the drum 20 and the fan 71, the user interface (e.g., including circuitry) 100, and a communication interface (e.g., including communication circuitry) 200. The dryer 1 may include the controller (e.g., including circuitry) 300 electrically connected to various electronic components and controlling the electronic components.

The user interface 100 may include various circuitry and obtain a user input and display various information about the operation of the dryer 1. The user interface 100 may include an input portion configured to obtain a user input, and a display configured to display information. The user interface 100 may further include a speaker to output sound.

The user interface 100 may display operation information of the dryer 1. For example, the user interface 100 may display a drying mode, a drying temperature, an estimated drying time and/or a time left until the end of the drying. The drying mode may include drying settings (e.g., a dryness level, an extra time for wrinkle free, and a drying time) determined in advance depending on the object’s type (e.g., shirts, bedclothes, or underwear) and material (e.g., cotton or wool). For example, standard drying may include a drying setting that may be applied to most objects to be dried, and bedclothes drying may include a drying setting optimized for drying bedclothes.

The communication interface 200 may include various communication circuitry and communicate with at least one of the user device 2 or the server 3 over a network. The controller 300 may obtain various information, various signals and/or various data from the user device 2 or the server 3 through the communication interface 200. For example, the communication interface 200 may receive a remote control signal from the user device 2. The controller 300 may obtain firmware and/or software for operation of the dryer 1 from the server 3 through the communication interface 200.

The communication interface 200 may include various communication circuits. The communication interface 200 may include a wireless communication circuit and/or a wired communication circuit. For example, a communication circuit that supports wireless communication schemes, such as wireless LAN, home RF, infrared communication, ultra-wide band (UWB) communication, Wi-Fi, Bluetooth™ and Zigbee may be provided.

The controller 300 may include various circuitry and be electrically connected to the components of the dryer 1 and may control the components of the dryer 1. For example, the controller 300 may control the motor 72 to rotate the drum 20 and the fan 71. The controller 300 may control the RF power supply 120, the frequency control circuit 130, and the impedance matching circuit 140 to supply power to the electrodes 90. The controller 300 may control the RF power supply 120, the frequency control circuit 130, and the impedance matching circuit 140 to improve drying efficiency when performing a drying operation of the object.

The controller 300 may include a processor (e.g., including processing circuitry) 310 and memory 320. The memory 320 may include a volatile memory (e.g., a static random access memory (S-RAM) or a dynamic RAM (D-RAM)) and a non-volatile memory (e.g., a read-only memory (ROM) or an erasable programmable ROM (EPROM)). The processor 310 and the memory 320 may be implemented in separate chips or in a single chip. In addition, a plurality of processors and a plurality of memories may be provided.

The processor 310 may include various processing circuitry and process various data and various signals based on instructions, data, a program and/or software stored in the memory 320. The processor 310 may generate control signals to control the components of the dryer 1. The processor 310 may include one or multiple cores.

The processor 310 may be configured to perform various operations of the dryer 1. The processor 310 may perform operations of the dryer 1 according to various embodiments by executing at least one instruction, algorithm, program and/or software stored in the memory 320. The processor 310 may control one or any combination of the components of the dryer 1.

The processor 310 may include various types of circuits. For example, the processor 310 may include at least one of a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), a many integrated core (MIC), a digital signal processor (DSP), a neural processing unit (NPU), a hardware accelerator, and/or a machine learning accelerator. Thus, the processor 310 may include various processing circuitry and/or multiple processors. For example, as used herein, including the claims, the term “processor” may include various processing circuitry, including at least one processor, wherein one or more of at least one processor, individually and/or collectively in a distributed manner, may be configured to perform various functions described herein. As used herein, when “a processor”, “at least one processor”, and “one or more processors” are described as being configured to perform numerous functions, these terms cover situations, for example and without limitation, in which one processor performs some of recited functions and another processor(s) performs other of recited functions, and also situations in which a single processor may perform all recited functions. Additionally, the at least one processor may include a combination of processors performing various of the recited /disclosed functions, e.g., in a distributed manner. At least one processor may execute program instructions to achieve or perform various functions.

The rectifier circuit 110 may be connected to the commercial power source AC, and may rectify AC power supplied from the commercial power source AC. For example, the rectifier circuit 110 may convert a negative voltage of an AC voltage to a positive voltage. The rectifier circuit 110 may include a full-wave rectifier circuit or a half-wave rectifier circuit. The AC voltage rectified by the rectifier circuit 110 may be input to the RF power supply 120.

The RF power supply 120 may operate using the AC voltage input from the AC power source. The RF power supply 120 may generate an RF signal and apply the RF signal to the electrodes 90. Sinusoidal power may be applied to the electrodes 90 due to the RF signal. The controller 300 may control the RF power supply 120 to adjust RF power applied to the electrodes 90. When RF power is supplied to the electrodes 90, an electric field for dielectric heating of the object may be produced in the drum 20. A phase of the RF power applied to each of the plurality of electrodes 90 may be different. An electric field may be produced in the drum 20 as RF power having different phases is applied to the plurality of electrodes 90.

The frequency control circuit 130 may adjust a frequency of a switching signal for turning on or off the RF power supply 120 based on a change in the magnitude of the AC voltage. The frequency of the switching signal may be referred to as a "switching frequency." The frequency control circuit 130 may be electrically connected to the controller 300, and may adjust the switching frequency for controlling an operation of the RF power supply 120 under the control of the controller 300. For example, the frequency control circuit 130 may determine the frequency of the switching signal for controlling the operation of the RF power supply 120 to be lower as the magnitude of the AC voltage increases. The magnitude of the AC voltage may represent an instantaneous value.

The frequency control circuit 130 may divide the magnitude of the AC voltage that changes over time into a plurality of sections (ranges). The frequency control circuit 130 may determine the switching frequency for controlling the operation of the RF power supply 120 differently for each of the plurality of sections. The controller 300 may divide the magnitude of the AC voltage into a plurality of sections, and set a plurality of threshold values for determining the switching frequency corresponding to each section. The frequency control circuit 130 may determine the switching frequency of the RF power supply 120 by comparing the magnitude of the AC voltage with the plurality of threshold values.

For example, the frequency control circuit 130 may determine the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value. The frequency control circuit 130 may determine the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value. The second threshold value may be set to be greater than the first threshold value. The frequency control circuit 130 may determine the frequency of the switching signal as a second frequency lower than the first frequency, based one magnitude of the AC voltage being greater than or equal to the second threshold value.

Although it has been illustrated that the switching frequency of the RF power supply 120 is adjusted by dividing the magnitude of the AC voltage input to the RF power supply 120 into three sections, the disclosure is not limited thereto. The magnitude of the AC voltage may, for example, be divided into three or more sections.

Existing dryers require many power conversion circuits to make an input voltage of an RF power supply a direct current (DC) voltage. For example, an existing dryer requires an electromagnetic interference (EMI) filter for removing noise contained in AC power, a power factor compensation circuit for compensating a power factor of the AC power, and a DC-DC converter for converting power output from the power factor compensation circuit into DC power suitable for the RF power supply. In the existing dryer, an effective value of the AC voltage supplied from the AC power source was used as an input voltage of the RF power supply. In the existing technology, because a continuously high voltage and/or power was applied to the RF power supply, high-frequency noise was continuously generated.

However, the dryer 1 according to the disclosure may not require a circuit structure and a control process for driving the RF power supply 120 using DC power. For example, the dryer 1 may not include an EMI filter, a power factor compensation circuit, and a DC-DC converter. Accordingly, compared to the existing technology, the type of circuits, the size of circuits, and the manufacturing cost of circuits included in the dryer 1 may be reduced, and a circuit control method may be simplified.

The dryer 1 according to the disclosure may minimize and/or reduce high-frequency noise by adjusting the switching frequency for controlling the RF power supply 120 according to the magnitude of the AC voltage while driving the RF power supply 120 using the AC voltage.

The impedance matching circuit 140 may be arranged between the RF power supply 120 and the plurality of electrodes 90. The RF signal generated by the RF power supply 120 may be transmitted to the electrode 90 through the impedance matching circuit 140.

The impedance matching circuit 140 may match output impedance of the RF power supply 120 and electrode impedance of the electrodes 90. In a case where there is a difference between the output impedance of the RF power supply 120 and the electrode impedance of the electrodes 90, reflected power may be generated from the electrodes 90, and power transmission efficiency may be reduced. To minimize/reduce the reflected power, the output impedance of the RF power supply 120 and the electrode impedance of the electrodes 90 need to be matched. The controller 300 may control the impedance matching circuit 140 to perform impedance matching.

The electrode impedance of the electrode 90 may vary depending on various factors, such as an amount of the object accommodated in the drum 20, a type of the object, a size of the object, an amount of water contained in the object, and a distribution of the object. For example, in a case where dielectrics (e.g., water) having a high dielectric constant exist between the two electrodes 90, charges may be accumulated on the dielectrics, and thus, a strength of the electric field formed between the two electrodes 90 may be reduced. When the strength of the electric field is reduced, the magnitude of the output voltage of the electrodes 90 may be reduced, and the electrode impedance may be reduced. As water contained in the object is removed with a progress of drying of the object, ever increasing electrode impedance may be detected.

As the drying proceeds, a rate of change in impedance of the object may decrease. The controller 300 may determine a dryness level of the object based on the rate of change in impedance of the object. The controller 300 may determine completion of the drying, based on the dryness level of the object reaching within a tolerance range of a preset reference dryness level. In addition, the controller 300 may determine completion of the drying based on an impedance value of the object being greater than or equal to a preset threshold value.

FIG. 6 is a block diagram illustrating an example circuit system for a drying operation of a dryer, according to various embodiments. FIG. 7 and FIG. 8 are diagrams illustrating example circuit structures of the circuit system shown in FIG. 6 according to various embodiments.

Referring to FIG. 6, FIG. 7 and FIG. 8, the rectifier circuit 110 may be connected to the commercial power source AC and may rectify AC power supplied from the commercial power source AC. For example, the rectifier circuit 110 may convert a negative voltage of an AC voltage to a positive voltage. The rectifier circuit 110 may include a full-wave rectifier circuit or a half-wave rectifier circuit. The rectifier circuit 110 may be provided as a bridge circuit including a plurality of diodes D1, D2, D3, and D4 connected in parallel and/or series. An output end of the rectifier circuit 110 may be connected to an input node Vin of the RF power supply 120. The AC voltage rectified by the rectifier circuit 110 may be input to the RF power supply 120.

The RF power supply 120 may be provided as a circuit including various elements for generating an RF signal. For example, the RF power supply 120 may include an electrolytic capacitor Cpa1, a capacitor Cpa2, a plurality of inductors Lpa1 and Lpa2, and a switching device SW1. The electrolytic capacitor Cpa1 may connect the Vin node to the ground GND. The switching device SW1 and the inductor Lpa1 may be connected in series between the Vin node and the ground GND. In addition, the inductor Lpa2 and the capacitor Cpa2 connected in series may be arranged between a node N1, at which the switching device SW1 is connected to the inductor Lpa1, and the impedance matching circuit 140.

The switching device SW1 of the RF power supply 120 may correspond to a transistor. The RF power supply 120 may be activated (ON) or deactivated (OFF) according to an operation of the switching device SW1. An operation of the RF power supply 120 may be controlled according to a switching signal applied to the switching device SW1. Based on the switching device SW1 being turned on, the operation of the RF power supply 120 may be activated. Based on the switching device SW1 being turned off, the operation of the RF power supply 120 may be deactivated.

The frequency control circuit 130 may include a plurality of D flip-flops 131-1, 131-2, ..., 131-N connected in series. The N D flip-flops (the N number of D flip-flops) may be connected in a daisy chain manner. Each of the plurality of D flip-flops 131-1, 131-2, ..., 131-N may include a data input pin D, a clock pin CLK, and an output pin Q.

The frequency control circuit 130 may include a plurality of inverters Inv1, Inv2, ..., InvN that connect the data input pin D and the output pin Q of each of the plurality of D flip-flops 131-1, 131-2, ..., 131-N. For example, when the output Q1 of the first D flip-flop 131-1 is inverted through an inverter and fed back to the D input, the first D flip-flop 131-1 may generate a frequency signal fsw1 having a frequency equal to 1/2 of the reference frequency. A reference frequency signal having the reference frequency may be generated by a frequency generator FG. The reference frequency signal generated by the frequency generator FG may be input as the clock CLK of the first D flip-flop 131-1.

When the plurality of D flip-flops 131-1, 131-2, ..., 131-N are connected in a daisy chain manner, the second D flip-flop 131-2 may output a frequency signal fsw2 having a frequency equal to 1/4 of the reference frequency, and the N-th D flip-flop 131-N may output a frequency signal fswN having a frequency equal to 1/2ⁿ of the reference frequency.

The number of D flip-flops may vary depending on the design. For example, the frequency control circuit 130 may include three D flip-flops. The frequency control circuit 130 may include the first D flip-flop 131-1 including a first clock pin connected to the frequency generator FG and a first output pin, the second D flip-flop 131-2 including a second clock pin connected to the first output pin of the first D flip-flop 131-1 and a second output pin, and the third D flip-flop including a third clock pin connected to the second output pin of the second D flip-flop 131-2 and a third output pin.

The frequency control circuit 130 may include a first comparator 134a that compares the magnitude of the AC voltage Vpa with a first threshold value Vth1 and outputs a first output value sel1, and a second comparator 134b that compares the magnitude of the AC voltage Vpa with a second threshold value Vth2 and outputs a second output value sel2. Each of the first output value sel1 of the first comparator 134a and the second output value sel2 of the second comparator 134b may correspond to a bit value.

The frequency control circuit 130 may include a multiplexer 132 for selecting one of the plurality of frequency signals. The first output value sel1 of the first comparator 134a and the second output value sel2 of the second comparator 134b may be input to the multiplexer 132. In other words, a 2-bit selection signal may be input to the multiplexer 132.

The multiplexer 132 may output, as a switching signal, one of the plurality of frequency signals output from each of the plurality of D flip-flops 131-1, 131-2, ..., 131-N and the reference frequency signal output from the frequency generator FG, based on the first output value sel1 of the first comparator 134a and the second output value sel2 of the second comparator 134b.

Although the frequency control circuit 130 is illustrated as including two comparators, the disclosure is not limited thereto. The frequency control circuit 130 may include two or more comparators. The number of sections for dividing the magnitude of the AC voltage and the number of bits of the selection signal input to the multiplexer 132 may vary depending on the number of comparators.

The frequency control circuit 130 may include a frequency shifter 133 that finely adjusts the frequency of the switching signal output from the multiplexer 132 within a preset range. The frequency shifter 133 may finely adjust the frequency of the frequency signal selected by the multiplexer 132 within a preset range. The frequency shifter 133 may include a voltage controlled oscillator (VCO). The frequency shifter 133 may change the frequency of the switching signal output from the multiplexer 132 based on a voltage input from the controller 300. The switching signal output from the frequency shifter 133 may be input to the switching device SW1 of the RF power supply 120.

The impedance matching circuit 140 may be provided as a circuit in which a plurality of inductors L, a plurality of capacitors C, and a plurality of switches S1, S2, S3, S4, S5, S6, S7, S8, and S9 are electrically connected in series and/or parallel. The plurality of switches S1, S2, S3, S4, S5, S6, S7, S8, and S9 included in the impedance matching circuit 140 may be opened or closed under the control of the controller 300. Impedance matching may be performed as the plurality of switches S1, S2, S3, S4, S5, S6, S7, S8, and S9 are controlled. The impedance matching circuit 140 is illustrated as including three inductors L connected in parallel, three capacitors C connected in parallel, and nine switches, but is not limited thereto. The structure of the impedance matching circuit 140 may be changed in various ways depending on the design.

An inductor Le for preventing/inhibiting a spark from occurring may be provided between the impedance matching circuit 140 and the electrode 90. In FIG. 7, the inductor Le is illustrated as being connected to the first electrode 90a, but is not limited thereto. An inductor for preventing/inhibiting a spark from occurring may also be provided between the second electrode 90b and the impedance matching circuit 140.

The controller 300 may perform impedance matching in response to an impedance change of the object by controlling the on-off of each of the plurality of switches S1, S2, S3, S4, S5, S6, S7, S8, and S9.

A plurality of impedance matching circuits 140 may be provided in correspondence with the plurality of electrodes 90. For example, one electrode 90 and one impedance matching circuit 140 may be provided as a set.

FIG. 9 is a graph illustrating a relationship between a change in a magnitude of an AC voltage and a frequency of a switching signal for turning on or off an RF power supply according to various embodiments.

Referring to the graph 900 of FIG. 9, the dryer 1 may set threshold values for dividing the magnitude of the AC voltage input to the RF power supply 120 into a plurality of sections. The dryer 1 may drive the RF power supply 120 at a lower switching frequency at a higher voltage, according to a result of comparing the magnitude of the AC voltage with the threshold values.

In a section where the magnitude of the AC voltage Vpa is less than a first threshold value Vth1, a relatively high switching frequency fsw1 (e.g., 27.12 MHz) may be selected. In a section where the magnitude of the AC voltage Vpa is greater than or equal to the first threshold value Vth1 and less than a second threshold value Vth2, a medium switching frequency fsw2 (e.g., 13.56 MHz) may be selected. In a section where the magnitude of the AC voltage Vpa is greater than or equal to the second threshold value Vth2, a relatively low switching frequency fsw3 (e.g., 6.78 MHz) may be selected. Fine adjustment of the selected switching frequency may be performed by the frequency shifter 133.

When driving the RF power supply 120 using a DC voltage, an effective value (RMS value) of an AC voltage is input to the RF power supply 120. When driving the RF power supply 120 using an AC voltage, because the magnitude of the AC voltage changes instantaneously, the magnitude of the voltage input to the RF power supply 120 repeatedly increases and decreases over time.

In a case where the magnitude of the voltage input to the RF power supply 120 is greater than the effective value, more noise may be generated than when the RF power supply 120 is driven with a DC voltage. A power amplifier for applying a high-frequency electric field to an object to be dried is susceptible to high-frequency noise because the power amplifier operates at a high frequency of 10 MHz or more, unlike a general power converter. The dryer 1 according to the disclosure may reduce noise by setting a lower switching frequency for operating the RF power supply 120 as the magnitude of the voltage input to the RF power supply 120 increases.

FIG. 10 is a graph illustrating a switching signal applied to an RF power supply based on a change in AC voltage magnitude according to various embodiments.

Referring to the graph 1000 of FIG. 10, the switching device SW1 of the RF power supply 120 may be turned on or off based on an input voltage Vgs. An on-off period of the switching device SW1 may be determined by a frequency of a switching signal (e.g., a switching frequency) input to the switching device SW1. The higher the frequency of the switching signal, the shorter the on-off period of the switching device SW1.

The dryer 1 may determine the frequency of the switching signal to be the relatively high switching frequency fsw1, based on the magnitude of the AC voltage Vpa being less than the first threshold value Vth1. The high switching frequency fsw1 may correspond to a reference frequency (e.g., 27.12 MHz).

The dryer 1 may determine the frequency of the switching signal to be the medium switching frequency fsw2, based on the magnitude of the AC voltage Vpa being greater than or equal to the first threshold value Vth1 and less than the second threshold value Vth2. The medium switching frequency fsw2 may correspond to a first frequency lower than the reference frequency.

The dryer 1 may determine the frequency of the switching signal to be the relatively low switching frequency fsw3, based on the magnitude of the AC voltage Vpa being greater than or equal to the second threshold value Vth2. The low switching frequency fsw3 may correspond to a second frequency lower than the first frequency.

The first threshold value Vth1 and the second threshold value Vth2 may be set differently depending on the design. Two threshold values for dividing the magnitude of the AC voltage into a plurality of sections are illustrated, but are not limited thereto. The number of threshold values may also vary depending on the design. Two or more threshold values for dividing the magnitude of the AC voltage input to the RF power supply 120 into three or more sections may be set.

There is a trade-off between drying performance and circuit system specifications. When the threshold value is high, drying performance increases, but an error may occur in the operation of the circuit system due to high frequency. When the threshold value is low, the stability of the circuit system may be improved, but drying performance may decrease because the section in which the circuit system operates at high frequency is reduced. The threshold value may be selected considering such a trade-off.

For example, because the waveform of the AC voltage output from the AC power source is a sine wave, the RMS value of the AC voltage is 0.707 times the peak voltage Vpeak. The second threshold value Vth2 may be set to 0.707 times the peak voltage Vpeak. The first threshold value Vth1 may be set to 0.35 times the peak voltage Vpeak. The first threshold value Vth1 may correspond to 50% of the second threshold value Vth2.

FIG. 11 is a graph illustrating an example operation of a frequency control circuit that determines a frequency of a switching signal applied to an RF power supply based on a change in AC voltage magnitude according to various embodiments.

As described above, the frequency control circuit 130 may include the multiplexer 132, the first comparator 134a, and the second comparator 134b. The first comparator 134a may compare the magnitude of the AC voltage Vpa with the first threshold value Vth1, and output the first output value sel1. The second comparator 134b may compare the magnitude of the AC voltage Vpa with the second threshold value Vth2, and output the second output value sel2.

Referring to the graph 1100 of FIG. 11, each of the first output value sel1 of the first comparator 134a and the second output value sel2 of the second comparator 134b may correspond to a bit value. The first output value sel1 and the second output value sel2 each have 1 bit, and a 2-bit selection signal may be input to the multiplexer 132.

The multiplexer 132 may output, as a switching signal, one of the plurality of frequency signals output from each of the plurality of D flip-flops 131-1, 131-2, ..., 131-N and the reference frequency signal output from the frequency generator FG in response to the input of the selection signal.

For example, in a case where the selection signal is 00, the multiplexer 132 may select a reference frequency signal having a reference frequency (e.g., 27.12 MHz) as a switching signal. In a case where the selection signal is 10, the multiplexer 132 may select a first frequency signal having a first frequency (e.g., 13.56 MHz) as a switching signal. In a case where the selection signal is 11, the multiplexer 132 may select a second frequency signal having a second frequency (e.g., 6.78 MHz) as a switching signal.

Although a 2-bit selection signal is illustrated as being input to the multiplexer 132, the disclosure is not limited thereto. The frequency control circuit 130 may include two or more comparators. The number of bits of the selection signal input to the multiplexer 132 may vary depending on the number of comparators.

FIG. 12 is a flowchart illustrating an example method for controlling a dryer according to various embodiments.

Referring to FIG. 12, the dryer 1 may identify a change in a magnitude of an AC voltage applied to the RF power supply 120 (1201). For example, the frequency control circuit 130 and/or the controller 300 of the dryer 1 may identify an instantaneous value of the AC voltage applied to the RF power supply 120. The dryer 1 may identify whether the magnitude (e.g., instantaneous value) of the AC voltage applied to the RF power supply 120 increases or decreases.

The dryer 1 may adjust a frequency of a switching signal for turning on or off the RF power supply 120 based on the change in the magnitude of the AC voltage (1202). The frequency of the switching signal may be referred to as a "switching frequency." For example, the frequency control circuit 130 may determine the frequency of the switching signal for controlling an operation of the RF power supply 120 to be lower as the magnitude of the AC voltage increases.

The frequency control circuit 130 of the dryer 1 may divide the magnitude of the AC voltage that changes over time into a plurality of sections. For example, the controller 300 of the dryer 1 may divide the magnitude of the AC voltage into a plurality of sections, and set a plurality of threshold values for determining the switching frequency corresponding to each section. The frequency control circuit 130 may determine the switching frequency for controlling the operation of the RF power supply 120 differently for each of the plurality of sections by comparing the magnitude of the AC voltage with the plurality of threshold values.

Each of the plurality of comparators 134a and 134b included in the frequency control circuit 130 may output a result of comparing the magnitude of the AC voltage with the plurality of threshold values as a bit value. The bit values output from each of the plurality of comparators 134a and 134b may be input to the multiplexer 132 as a selection signal.

The multiplexer 132 may output, as a switching signal, one of the plurality of frequency signals output from each of the plurality of D flip-flops 131-1, 131-2, ..., 131-N and the reference frequency signal output from the frequency generator FG in response to the input of the selection signal.

The frequency of the switching signal output from the multiplexer 132 may be finely adjusted within a preset range by the frequency shifter 133. The switching signal having the finely adjusted frequency may be input to the switching device SW1 of the RF power supply 120. The switching device SW1 may repeatedly turn on and off based on the switching signal. The RF power supply 120 may be activated (ON) or deactivated (OFF) according to the ON or OFF of the switching device SW1.

As described above, the dryer 1 according to the disclosure may use the AC voltage to operate the RF power supply 120 and adjust the switching frequency for controlling the RF power supply 120. Accordingly, high-frequency noise caused using the AC voltage may be minimized, and the circuit system may be simplified.

FIG. 13 is a flowchart illustrating an example method for controlling the dryer described in FIG. 12 according to various embodiments.

Referring to FIG. 13, the dryer 1 may identify the change in the magnitude of the AC voltage applied to the RF power supply 120 (1301). Operation 1301 corresponds to operation 1201 of FIG. 12.

The frequency control circuit 130 of the dryer 1 may determine the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value (1302, 1303). The frequency control circuit 130 may determine the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value (1304, 1305). The second threshold value may be set to be greater than the first threshold value. The frequency control circuit 130 may determine the frequency of the switching signal as a second frequency lower than the first frequency, based on the magnitude of the AC voltage being greater than or equal to the second threshold value (1306).

Although it has been illustrated that the switching frequency of the RF power supply 120 is adjusted by dividing the magnitude of the AC voltage input to the RF power supply 120 into three sections, the disclosure is not limited thereto. The magnitude of the AC voltage may be divided into three or more sections, and a switching frequency corresponding to each section may be determined.

According to an example embodiment of the disclosure, a dryer may include: a chamber; a first electrode disposed on a first side of the chamber; a second electrode disposed on a second side of the chamber, the second side facing the first side; a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to the first electrode and the second electrode; an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode; and a frequency control circuit configured to adjust a frequency of a switching signal for turning the RF power supply on or off based on a change in a magnitude of the AC voltage.

The frequency control circuit may be configured to determine the frequency of the switching signal to be lower as the magnitude of the AC voltage increases.

The frequency control circuit may be configured to determine the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value. The frequency control circuit may be configured to determine the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value greater than the first threshold value. The frequency control circuit may be configured to determine the frequency of the switching signal as a second frequency lower than the first frequency, based on the magnitude of the AC voltage being greater than or equal to the second threshold value.

The frequency control circuit may include: a plurality of D flip-flops connected in series; a first comparator configured to compare the magnitude of the AC voltage with the first threshold value and output a first output value; a second comparator configured to compare the magnitude of the AC voltage with the second threshold value and output a second output value; and a multiplexer configured to output, as the switching signal, one of a plurality of frequency signals output from each of the plurality of D flip-flops and a reference frequency signal output from a frequency generator, based on the first output value and the second output value.

The frequency control circuit may further include a frequency shifter configured to finely adjust the frequency of the switching signal output from the multiplexer within a preset range.

The frequency control circuit may further include an inverter configured to connect a data input pin and an output pin of each of the plurality of D flip-flops.

The plurality of D flip-flops may include: a first D flip-flop including a first clock pin connected to the frequency generator and a first output pin; a second D flip-flop including a second clock pin connected to the first output pin of the first D flip-flop and a second output pin; and a third D flip-flop including a third clock pin connected to the second output pin of the second D flip-flop and a third output pin.

According to an example embodiment of the disclosure, in an example method for controlling a dryer including a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to a first electrode and a second electrode, and an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode, the method may include: identifying, by a frequency control circuit, a change in a magnitude of the AC voltage; and adjusting, by the frequency control circuit, a frequency of a switching signal for turning the RF power supply on or off based on the change in the magnitude of the AC voltage.

The adjusting of the frequency of the switching signal may include determining the frequency of the switching signal to be lower as the magnitude of the AC voltage increases.

The adjusting of the frequency of the switching signal may include: determining the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value; determining the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value greater than the first threshold value; and determining the frequency of the switching signal as a second frequency lower than the first frequency, based on the magnitude of the AC voltage being greater than or equal to the second threshold value.

According to the disclosure, the dryer and the method for controlling the same may drive an RF power supply using AC power supplied from an AC power source. The dryer and the method for controlling the same may not require a circuit structure and a control process for driving the RF power supply using DC power. Accordingly, compared to existing technologies, the size and manufacturing cost of circuits may be reduced, and the circuit control method may be simplified.

The dryer and the method for controlling the same may minimize high-frequency noise by adjusting a switching frequency for controlling the RF power supply according to a magnitude of AC voltage.

The dryer and the method for controlling the same may enable adaptive impedance matching by adjusting a switching frequency according to an AC voltage, and may adaptively respond to changes in load impedance caused by movement of an object to be dried and a drying progress.

The disclosed embodiments may be implemented in the form of a recording medium that stores instructions executable by a computer. The instructions may be stored in the form of program codes, and when executed by a processor, the instructions may generate a program module to perform the operations of the disclosed embodiments.

The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, a "non-transitory", storage medium is tangible and may not include a signal (e.g., an electromagnetic wave), but rather that data is semi-permanently or temporarily stored in the storage medium. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

The method according to various embodiments disclosed herein may be provided in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed (e.g., download or upload) through an application store (e.g., Play Store^TM) online or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be stored at least semi-permanently or may be temporarily generated in a storage medium, such as a memory of a server of a manufacturer, a server of an application store, or a relay server.

Although various example embodiments of the disclosure have been described with reference to the accompanying drawings, one skilled in the art will appreciate that various modifications may be easily made without departing from the technical spirit or essential features of the disclosure. Therefore, the foregoing embodiments should be regarded as illustrative rather than limiting in all aspects. It will also be understood that any of the embodiment(s) described herein may be used in conjunction with any other embodiment(s) described herein.

Claims

1. A dryer, comprising:

a chamber;

a first electrode disposed on a first side of the chamber;

a second electrode disposed on a second side of the chamber, the second side facing the first side;

a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage received from an AC power source and apply an RF signal to the first electrode and the second electrode;

an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode; and

a frequency control circuit configured to adjust a frequency of a switching signal to turn the RF power supply on or off based on a change in a magnitude of the AC voltage.

2. The dryer of claim 1, wherein the frequency control circuit is configured to determine the frequency of the switching signal to be lower as the magnitude of the AC voltage increases.

3. The dryer of claim 1, wherein the frequency control circuit is configured to determine the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value, determine the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value greater than the first threshold value, and determine the frequency of the switching signal as a second frequency lower than the first frequency, based on the magnitude of the AC voltage being greater than or equal to the second threshold value.

4. The dryer of claim 3, wherein the frequency control circuit comprises:

a plurality of D flip-flops connected in series;

a first comparator configured to compare the magnitude of the AC voltage with the first threshold value and output a first output value;

a second comparator configured to compare the magnitude of the AC voltage with the second threshold value and output a second output value; and

a multiplexer configured to output, as the switching signal, one of a plurality of frequency signals output from each of the plurality of D flip-flops and a reference frequency signal output from a frequency generator, based on the first output value and the second output value.

5. The dryer of claim 4, wherein the frequency control circuit further comprises a frequency shifter comprising circuitry configured to adjust the frequency of the switching signal output from the multiplexer within a specified range.

6. The dryer of claim 4, wherein the frequency control circuit further comprises an inverter configured to connect a data input pin and an output pin of each of the plurality of D flip-flops.

7. The dryer of claim 5, wherein the plurality of D flip-flops comprises:

a first D flip-flop including a first clock pin connected to the frequency generator and a first output pin;

a second D flip-flop including a second clock pin connected to the first output pin of the first D flip-flop and a second output pin; and

a third D flip-flop including a third clock pin connected to the second output pin of the second D flip-flop and a third output pin.

8. The dryer of claim 4, wherein the first output value of the first comparator and the second output value of the second comparator each include bit values.

9. A method for controlling a dryer comprising a radio frequency (RF) power supply configured to operate using an alternating current (AC) voltage input from an AC power source and apply an RF signal to a first electrode and a second electrode, and an impedance matching circuit configured to perform impedance matching between the RF power supply and the first electrode and the second electrode, the method comprising:

identifying, by a frequency control circuit, a change in a magnitude of the AC voltage; and

adjusting, by the frequency control circuit, a frequency of a switching signal for turning the RF power supply on or off based on the change in the magnitude of the AC voltage.

10. The method of claim 9, wherein the adjusting of the frequency of the switching signal comprises determining the frequency of the switching signal to be lower as the magnitude of the AC voltage increases.

11. The method of claim 9, wherein the adjusting of the frequency of the switching signal comprises:

determining the frequency of the switching signal as a reference frequency, based on the magnitude of the AC voltage being less than a first threshold value;

determining the frequency of the switching signal as a first frequency lower than the reference frequency, based on the magnitude of the AC voltage being greater than or equal to the first threshold value and less than a second threshold value greater than the first threshold value; and

determining the frequency of the switching signal as a second frequency lower than the first frequency, based on the magnitude of the AC voltage being greater than or equal to the second threshold value.