Dryer and method for controlling same

Abstract

The disclosed dryer may comprise: a drum; an electrode unit including a plurality of electrodes disposed along the outer circumferential surface of the drum while being spaced apart from each other; an RF power supply unit including a switching element configured to receive an input signal, the RF power supply unit being configured to amplify the input signal to generate RF power applied to the electrode unit; an impedance matching circuit configured to perform impedance matching between the RF power supply unit and the electrode unit; and an input signal changer configured to classify a plurality of objects to be dried according to preset categories on the basis of determining that the plurality of objects to be dried are accommodated in the drum, generate an optimal frequency input signal regarding each of the objects to be dried classified into the different categories by alternating in time division on the basis of the plurality of objects to be dried being classified into the different categories, and transmit the optimal frequency input signal to the switching element.

Description

Dryer and method of controlling the same

[0001] The disclosed invention relates to a dryer capable of drying an object through genetic heating and a method for controlling the same.

[0002] A dryer is a device that dries an object (e.g., clothing) by removing moisture contained within the object. Various types of drying devices exist. For example, there is a dryer that supplies hot air to a drum containing the object to dry it.

[0003] Specifically, there are dryers that can dry objects using dielectric heating using RF (Radio Frequency). Conventional dryers that use dielectric heating place an object between two parallel flat electrodes and heat the water contained in the object by generating an electric field between the two flat electrodes. Conventional dryers that use dielectric heating not only dry simple clothes, but also have sterilizing and deodorizing effects, so they can manage a variety of items such as shoes and bags. In these cases, dryers used technologies such as weight sensors or infrared cameras to identify the object. However, this method had the disadvantage of high circuit manufacturing costs and low accuracy.

[0004] Furthermore, as the drying target becomes more diverse, conditions can vary depending on the target's volume, material, condition, humidity, etc. Accordingly, to increase drying efficiency, it is necessary to apply RF power appropriate for each target.

[0005] The disclosed invention provides a dryer and a control method thereof capable of identifying a drying material accommodated in a drum, classifying the category of the identified drying material, and, when the category of the drying material is determined to be multiple, providing optimal RF power for each identified drying material in a time-division manner.

[0006] In one embodiment, a dryer may include: a drum; an electrode unit including a plurality of electrodes spaced apart from each other along an outer surface of the drum; an RF power supply unit including a switching element receiving an input signal and amplifying the input signal to generate RF power applied to the electrode unit; an impedance matching circuit performing impedance matching between the RF power supply unit and the electrode unit; and an input signal variable unit classifying the plurality of objects to be dried into preset categories based on a determination that the plurality of objects to be dried are accommodated in the drum, and generating an optimal frequency input signal for each object to be dried into the different categories alternately in a time-division manner based on the plurality of objects to be dried being classified into different categories, and transmitting the optimal frequency input signal to the switching element.

[0007] In one embodiment, a method for controlling a dryer comprising an electrode unit including a plurality of electrodes spaced apart from each other along an outer surface of a drum, an RF power supply unit including a switching element receiving an input signal and amplifying the input signal to generate RF power applied to the electrode unit, an impedance matching circuit performing impedance matching between the RF power supply unit and the electrode unit, and an input signal varying unit varying the frequency of an input signal input to the switching element may include detecting an output voltage and an output current of an output terminal of the impedance matching circuit, determining whether a plurality of items to be dried are received in the drum based on the output voltage and the output current, classifying the plurality of items to be dried based on the determination that the plurality of items to be dried are received in the drum according to a preset category, generating an optimal frequency input signal for each of the items to be dried classified into the different categories alternately in a time-division manner based on the classification of the plurality of items to be dried into different categories, and transmitting the optimal frequency input signal to the switching element.

[0008] According to a dryer and a control method thereof according to one embodiment, by providing an optimal RF power according to an object to be dried, drying efficiency can be maximized while preventing damage to the object to be dried.

[0009] According to a dryer and a control method thereof according to one embodiment, even when drying various categories of objects at the same time, the dryness level of each object can be maintained evenly.

[0010] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0011] Figure 1 illustrates a dryer according to one embodiment.

[0012] Figure 2 is a cross-sectional view of a dryer according to one embodiment.

[0013] FIG. 3 is a drawing for explaining the operation of a genetic heating device according to one embodiment.

[0014] Figure 4 is a control block diagram of a dryer according to one embodiment.

[0015] Figures 5 and 6 illustrate detailed circuit structures of a genetic heating device according to one embodiment.

[0016] Figure 7 is a graph measuring the gain value according to the frequency change by changing the drying material accommodated in the drum.

[0017] FIG. 8 is a control flowchart of a dryer for determining whether a plurality of drying materials are accommodated in a drum according to one embodiment.

[0018] Figures 9 to 11 are graphs showing the waveforms of voltage and current measured at the output terminal of the impedance matching circuit according to the dry matter accommodated in the drum.

[0019] FIG. 12 is a control flowchart of a dryer for classifying a plurality of objects to be dried by category according to one embodiment and transmitting an optimal frequency input signal for each object to be dried by category to an RF power supply.

[0020] FIG. 13 is a control flowchart of a dryer for supplying optimal RF power to each of the dry materials classified into different categories in a time-division manner according to one embodiment.

[0021] Fig. 14 is a drawing showing an operation timeline of a dryer according to the control method of Fig. 13.

[0022] FIG. 15 is a control flowchart of a dryer for supplying optimal RF power to each of the dry materials classified into different categories in a time-division manner according to another embodiment.

[0023] Fig. 16 is a drawing showing an operation timeline of a dryer according to the control method of Fig. 15.

[0024] Figure 17 is a drawing for explaining the change in the gain value according to the overlapping of the drying object as the drying process is performed.

[0025] Figure 18 is a drawing showing an example of a drying machine's overlapping process for eliminating the overlapping phenomenon of drying materials.

[0026] FIG. 19 is a control flowchart of a dryer for eliminating the overlapping phenomenon of objects to be dried in supplying optimal RF power to each object to be dried classified into different categories in a time-division manner according to one embodiment.

[0027] Fig. 20 is a drawing showing an operation timeline of a dryer according to the control method of Fig. 19.

[0028] Fig. 21 is a control flowchart of a dryer (1) for eliminating the overlapping phenomenon of objects to be dried in supplying optimal RF power to each object to be dried classified into different categories in a time-division manner according to another embodiment.

[0029] Fig. 22 is a drawing showing an operation timeline of a dryer (1) according to the control method of Fig. 21.

[0030] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to include various modifications, equivalents, or substitutes of the embodiments.

[0031] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0032] The singular form of a noun corresponding to an item may include one or more items, unless the context clearly indicates otherwise.

[0033] In this document, each of the phrases "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 of the items listed together in that phrase, or all possible combinations thereof.

[0034] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0035] When a component (e.g., a first component) is referred to as being “coupled” or “connected” to another component (e.g., a second component), with or without the terms “functionally” or “communicatively,” it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0036] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0037] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0038] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0039] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0040] The operating principle and embodiments of the present invention will be described with reference to the attached drawings below.

[0041] Figure 1 illustrates a dryer according to one embodiment.

[0042] Referring to FIG. 1, a dryer (1) may include a cabinet (1a) forming an exterior, and a drum (20) rotatably installed within the cabinet (1a). The cabinet (1a) may be provided in an approximately hexahedral shape. The cabinet (1a) may include a top cover (1b) forming an upper surface, a front cover (1c) forming a front surface, and a base forming a bottom surface.

[0043] For example, the front cover (1c), the top cover (1b), and the base forming the cabinet (1a) may be separately prepared and assembled. As another example, some components forming the cabinet (1a) (e.g., the front cover, the top cover, and the base) may be formed integrally.

[0044] An inlet (31) is provided on the front of the cabinet (1a) for loading or unloading clothing (not shown) as an object into or out of the drum (20). The dryer (1) may include a door (50) provided to open and close the inlet (31) formed on the front cover (1c). After opening the door (50), a user can load or unload an object into or out of the drum (20) through the inlet (31). When the inlet (31) is closed and the dryer (1) begins to operate, a door lock may lock the door (50).

[0045] A user interface (100) for interaction between a user and the dryer (1) may be provided on the upper front side of the cabinet (1a). The user interface (100) may obtain user input and display various information regarding the dryer (1). The location of the user interface (100) is not limited to the front. The user interface (100) may be provided at various locations of the dryer (1).

[0046] The user interface (100) may include a display. Furthermore, the user interface (100) may include an input unit for obtaining user input regarding the operation of the dryer (1). The input unit may include a rotatable dial and various buttons. Additionally, the user interface (100) may include various types of input units and displays.

[0047] The display may be provided in the form of various display panels. For example, the display may include a liquid crystal display panel (LCD panel), a light emitting diode panel (LED panel), an organic light emitting diode panel (OLED panel), or a micro LED panel. The display may also be used as an input device, including a touch screen.

[0048] The display can display user-entered information or information provided to the user on various screens. The display can display information related to the operation of the dryer (1) in the form of at least an image or text. In addition, the display can display a graphical user interface (GUI) that enables control of the dryer (1). That is, the display can display UI elements (User Interface Elements), such as icons.

[0049] The input unit can transmit an electrical signal (voltage or current) corresponding to a user input to the control unit (300). The input unit can include various buttons and / or dials. For example, the input unit can include at least one of a power button for turning the dryer (1) on or off, a start / stop button for starting or stopping the drying operation, a drying mode button for selecting a drying mode, a temperature button for setting a drying temperature, and a time button for setting a drying time. The various buttons can be provided as physical buttons or touch buttons.

[0050] The dial included in the input unit may be configured to be rotatable. UI elements displayed on the display may move sequentially as the dial rotates. 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. Different drying modes may be selected depending on the location of the object within the drum (20), the type of the object, and / or the amount of the object.

[0051] The dryer (1) may include a filter (40) detachably mounted on the front cover (1c). The filter (40) may filter out foreign substances such as lint that flow together with the air circulating inside the drum (20).

[0052] Figure 2 is a cross-sectional view of a dryer according to one embodiment.

[0053] Referring to Fig. 2, a cylindrical drum (20) may be provided inside the cabinet (1a). The drum (20) is provided to accommodate an object therein and enable drying. The drum (20) may be provided to be rotatable by receiving power from a motor (72). The drum (20) may be provided inside the cabinet (1a) to be rotatable around a rotating axis that is provided approximately horizontally with respect to the ground.

[0054] A lifter (21) may be provided on the inner surface of the drum (20) to lift an object when the drum (20) rotates. Depending on the rotation speed of the drum (20), the object may be repeatedly raised and lowered by the lifter (21). A roller (22) may be provided on the outer surface of the drum to support the drum (20) so that it rotates smoothly.

[0055] The driving device may be placed on the inner lower part of the cabinet (1a). The driving device may be mounted on the base. The driving device may include a motor (72), a pulley (74) and a belt (75) for transmitting the power of the motor (72) to the drum (20).

[0056] A pulley (74) can be connected to a rotary shaft (73) connected to a motor (72). When the rotary shaft (73) is rotated by the motor (72), the pulley (74) can rotate together with the rotary shaft (73). A belt (75) can be installed so as to be wound around the outer surface of the pulley (74) and the outer surface of the drum (20). When the belt (75) is rotated by the driving force of the motor (72), the drum (20) can rotate together with the belt (75). The drum (20) can rotate clockwise or counterclockwise.

[0057] A passage (80) for circulating air may be formed inside the cabinet (1a) and inside the drum (20). The passage (80) may include an air exhaust passage (81) for discharging air from inside the drum (20) to outside the drum (20), and an air supply passage (82) for supplying air to inside the drum (20).

[0058] The dryer (1) may include an exhaust duct (60) forming an air exhaust path (81). A filter (40) may be arranged at an inlet (61) of the exhaust duct (60). The exhaust duct (60) may pass through the cabinet (1a), and an outlet (63) of the exhaust duct (60) may be exposed to the outside of the cabinet (1a). Air flowing into the inlet (61) of the exhaust duct (60) may be filtered while passing through the filter (40). The filter (40) may filter out foreign substances such as lint contained in the air.

[0059] A fan (71) for circulating air may be provided inside the cabinet (1a). By the rotation of the fan (71), air inside the drum (20) may be introduced into the exhaust duct (60). In addition, by the rotation of the fan (71), air may be supplied into the drum (20) through the air supply path (83) and the air inlet (20b) of the drum (20). The air supplied into the drum (20) may be used for drying the object.

[0060] The motor (72) can rotate not only the drum (20) but also the fan (71). Although the drum (20) and the fan (71) are exemplified as being driven by a single motor (72), this is not limited thereto. A separate fan motor (not shown) may be provided to drive the fan (71). In addition, the motor (72) may be directly connected to the drum (20) to rotate the drum (20). If the motor (72) is directly connected to the drum (20), the pulley (74) and the belt (75) may be omitted.

[0061] A plurality of electrodes may be provided between the cabinet (1a) and the drum (20). For example, a drying electrode (90a) and a sterilizing electrode (91c) may be provided between the cabinet (1a) and the drum (20). The drying electrode (90a) and the sterilizing electrode (91c) may be spaced apart from each other along the periphery of the drum (20). The drying electrode (90a) and the sterilizing electrode (91c) may be cross-spaced. The drying electrode (90a) and the sterilizing electrode (91c) may also be spaced apart from the cabinet (1a) and the drum (20).

[0062] A dryer (1) according to one embodiment may include a dielectric heating device (101), which will be described below with reference to FIG. 3.

[0063] FIG. 3 is a drawing for explaining the operation of a genetic heating device (101) according to one embodiment.

[0064] A dielectric heating device (101) according to one embodiment may include an RF power supply unit (140) and a plurality of electrodes (170a, 170b). At this time, a high-frequency electric field (230) may be formed between the first electrode (170a) and the second electrode (170b) based on the power provided from the RF power supply unit (140).

[0065] When an object (hereinafter referred to as “object to be dried”) located between the first electrode (170a) and the second electrode (170b) contains polar molecules (240) (e.g., water molecules), the object can undergo rotational motion and / or vibrational motion by a high-frequency electric field (230). The object can be heated by the motion of the polar molecules (240) within the object.

[0066] Polar molecules (240) within an object can be located on the surface and inside of the object, and the part of the object that is heated can be determined depending on the location where the polar molecules (240) are located within the object.

[0067] According to a dielectric heating device (101) according to one embodiment, an object can be uniformly heated due to the movement of polar molecules (240) within the object.

[0068] Fig. 4 is a control block diagram of a dryer (1) according to one embodiment.

[0069] Referring to FIG. 4, the dryer (1) may include a dielectric heating device (101) to perform a drying process using dielectric heating. For example, the dielectric heating device (101) may include an EMI (Electro Magnetic Interference) filter (110), a power factor correction circuit (120), a DC converter (130), an RF power supply (140), a switch (150), an impedance matching circuit (160), an electrode unit (170), and / or an input signal variable unit (180).

[0070] Additionally, the dryer (1) may include a motor (72) that rotates the drum (20) and the fan (71), a user interface (100), and a communication interface (200).

[0071] Additionally, the dryer (1) may include a control unit (300) that is electrically connected to the dielectric heating device (101), the user interface (100), the communication interface (200) and / or the motor (72) and controls the dielectric heating device (101), the user interface (100), the communication interface (200) and / or the motor (72).

[0072] The user interface (100) can acquire user input and display various information regarding the operation of the dryer (1). The user interface (100) can include an input unit for acquiring user input and a display for displaying information. In addition, the user interface (100) can also include a speaker for outputting sound.

[0073] The user interface (100) may display operating 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 remaining time until the end of drying. The drying mode may include predetermined drying settings (e.g., drying level, additional time to prevent wrinkles, drying time) depending on the type of the object to be dried (e.g., shirt, blanket, underwear) and material (e.g., cotton, wool). For example, the standard drying may include drying settings applicable to most objects, and the blanket drying may include drying settings optimized for drying blankets. The drying settings of the drying mode may also include a sterilization time and a sterilization intensity.

[0074] Additionally, the user interface (100) may display the sterilization mode separately. The user may select the sterilization mode by manipulating the user interface (100). When the sterilization mode is selected, the dryer (1) may independently perform the sterilization operation.

[0075] The communication interface (200) can perform a connection with at least one of a user device (2) or a server (3) via a network. The control unit (300) can obtain various information, various signals, and / or various data from an external device (e.g., a user device or a server) via the communication interface (200). For example, the communication interface (200) can receive a remote control signal from the user device. The control unit (300) can obtain firmware and / or software for the operation of the dryer (1) from the server via the communication interface (200).

[0076] The communication interface (200) may include various communication circuits. The communication interface (200) may include wireless communication circuits and / or wired communication circuits. For example, a communication circuit supporting wireless communication methods such as wireless local area network (WLAN), home radio frequency (RF), infrared communication, ultra-wide band (UWB) communication, Wi-Fi, Bluetooth, and Zigbee may be provided.

[0077] The control unit (300) can be electrically connected to components of the dryer (1) and can control the components of the dryer (1). For example, the control unit (300) can control the motor (72) to rotate the drum (20) and the fan (71). The control unit (300) can control components constituting the dielectric heating device (101) to supply power to the electrode unit (170) (e.g., an EMI filter (110), a power factor correction circuit (120), a DC converter (130), an RF power supply (140), a switch (150), and / or an impedance matching circuit (160)).

[0078] The control unit (300) may include a processor (310) and a memory (320). The memory (320) may include volatile memory (e.g., S-RAM, D-RAM) and non-volatile memory (e.g., ROM, EPROM). The processor (310) and the memory (320) may be implemented as separate chips or as a single chip. In addition, a plurality of processors and a plurality of memories may be provided. The processor (310) may process various data and various signals using instructions, data, programs, and / or software stored in the memory (320). The processor (310) may generate control signals for controlling components of the dryer (1). The processor (310) may include one core or a plurality of cores.

[0079] The dielectric heating device (101) may include an EMI (Electro Magnetic Interference) filter (110), a power factor correction circuit (120), a DC converter (130), an RF power supply (140), a switch (150), an impedance matching circuit (160), an electrode section (170), and / or an input signal variable section (180).

[0080] An EMI (Electro Magnetic Interference) filter (110) can remove noise contained in AC power supplied from a commercial power source (AC). The EMI filter (110) can be provided as a circuit in which various electronic components, such as capacitors, inductors, and diodes, are connected in parallel and / or in series. The EMI filter (110) can discharge noise contained in AC power through a ground line. The EMI filter (110) can be provided as a passive filter or an active filter.

[0081] The power factor correction circuit (120) can compensate for the power factor of AC power. The power factor correction circuit (120) can compensate for the power factor by reducing or eliminating reactive power among the active power and reactive power that constitute the AC power. By compensating for the power factor, power loss can be reduced. The power factor correction circuit (120) can be provided as a circuit in which various electronic components, such as capacitors, inductors, and diodes, are connected in parallel and / or in series. The power factor correction circuit (120) can be controlled by the control unit (300).

[0082] The DC converter (130) can convert the power output from the power factor correction circuit (120) into DC power suitable for the RF power supply (140). The DC converter (130) can transmit the converted DC power to the RF power supply (140). The DC converter (130) can be provided as a circuit in which various electronic components such as transistors, inductors, and diodes are connected in parallel and / or in series.

[0083] The control unit (300) can control the DC converter (130) to adjust the magnitude of the voltage applied to the electrode unit (170). As the power supplied to the RF power supply unit (140) increases, the amplitude of the RF signal increases, and the magnitude of the voltage applied to the electrode unit (170) can increase. The magnitude of the voltage can be expressed as an effective value.

[0084] The RF power supply unit (140) can generate an RF signal and apply the RF signal to the electrode unit (170). A sinusoidal power can be applied to the electrode unit (170) by the RF signal. The control unit (300) can control the RF power supply unit (140) to adjust the RF power applied to the electrode unit (170). When RF power is supplied to the electrode unit (170), an electric field for dielectric heating of an object can be generated within the drum (20).

[0085] The switch (150) can connect or short-circuit the RF power supply (140) and the impedance matching circuit (160). The control unit (300) is electrically connected to the switch (150) and can control the switch (150). Depending on the switching of the switch (150), the RF power supply (140) and the impedance matching circuit (160) can be connected or short-circuited.

[0086] The control unit (300) can control the switch (150) to perform impedance matching for the drying material having the changed frequency as the optimal frequency before applying RF power of the changed frequency to the electrode unit (170) of the dryer (1) in a time-division manner and alternately supplying the optimal RF power for each drying material.

[0087] An impedance matching circuit (160) may be provided between the RF power supply (140) and the electrode unit (170). RF power generated by the RF power supply (140) may be transmitted to the electrode unit (170) through the impedance matching circuit (160). The impedance matching circuit (160) may match the output impedance of the RF power supply (140) and the electrode impedance of the electrode unit (170). If there is a difference between the output impedance of the RF power supply (140) and the electrode impedance of the electrode unit (170), reflected power is generated from the electrode unit (170), and power transmission efficiency is reduced. In order to minimize the reflected power, matching of the output impedance of the RF power supply (140) and the electrode impedance of the electrode unit (170) needs to be performed. The control unit (300) can perform impedance matching by controlling the impedance matching circuit (160).

[0088] The electrode unit (170) may include at least one electrode (e.g., 170a, 170b of FIG. 3) that receives RF power from the RF power supply unit (140). The electrode unit (170) may include one ground electrode and at least one electrode that receives RF power from the RF power supply unit (140). When the active unit (170) includes a plurality of electrodes that receive RF power from the RF power supply unit (140), the phases of the RF power applied to each of the plurality of electrodes may be different.

[0089] As RF power having different phases is applied to the electrode portions (170), a rotating electric field can be generated within the drum (20). That is, the intensity of the electric field generated between two adjacent electrode portions (170) can periodically repeat increasing and decreasing.

[0090] The input signal variable part (180) can detect the resonance point or the resonance frequency at the resonance point for each of the plurality of objects to be dried contained in the drum (20) based on the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode part (170)). In addition, the input signal variable part (180) can detect the load characteristic for each of the plurality of objects to be dried contained in the drum (20) based on the phase difference of the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode part (170)).

[0091] The electrode impedance of the electrode unit (170) may change depending on various factors such as the amount of the material to be dried contained in the drum (20), the category of the material to be dried, the size of the material to be dried, the amount of water contained in the material to be dried, and / or the distribution state of the material to be dried. Accordingly, the magnitude or phase difference of the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode unit (170)) may also change.

[0092] The input signal variable section (180) can determine whether multiple objects to be dried are accommodated in the drum (20) by measuring a gain value according to the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode section (170)) while varying the frequency of the input signal applied to the RF power supply section (140).

[0093] In addition, when it is determined that multiple objects to be dried are accommodated in the drum (20), the input signal variable section (180) can determine the classification category of the objects to be dried based on the phase difference of the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode section (170)).

[0094] Accordingly, when a plurality of objects to be dried are classified into different categories, the optimal frequency input signal for each object to be dried classified into the different categories can be generated alternately in a time-division manner based on the classification of the plurality of objects to be dried into the different categories, and the generated input signal can be transmitted to the RF power supply unit (140). In other words, the input signal variable unit (180) can alternately provide the optimal frequency input signal for each object to be dried to the RF power supply unit (140). That is, the input signal variable unit (180) can vary the input signal input to the RF power supply unit (140) according to the object to be dried so that the maximum drying efficiency can be obtained for each object to be dried.

[0095] In addition, the input signal variable unit (180) can control at least one component constituting the dielectric heating device (101). That is, the input signal variable unit (180) can control the EMI (Electro Magnetic Interference) filter (110), the power factor correction circuit (120), the DC converter (130), the RF power supply unit (140), the switch (150) and / or the impedance matching circuit (160) performed by the aforementioned control unit (300). For example, the input signal variable unit (180) can control the impedance matching circuit (160) to perform impedance matching of the electrode unit (170) corresponding to each object to be dried when alternately providing the optimal frequency input signal for each object to be dried to the RF power supply unit (140). Additionally, the input signal variable section (180) may control the switch (150) to short-circuit between the RF power supply section (140) and the impedance matching circuit (160) before impedance matching is performed by the impedance matching circuit (160).

[0096] Figures 5 and 6 illustrate a detailed circuit structure of a genetic heating device (101) according to one embodiment.

[0097] Referring to FIGS. 5 and 6, an EMI filter (110) is connected to a commercial power source (AC) and can remove noise from AC power supplied from the commercial power source (AC). The EMI filter (110) can provide AC power with noise removed to a power factor correction circuit (120). The EMI filter (110) can be provided as a circuit in which various elements are connected in parallel and / or in series. For example, the EMI filter (110) can include a plurality of capacitors (C1, C2) connected in parallel, a plurality of inductors (L1, L2) implementing a transformer, and a plurality of diodes (D1, D2, D3, D4) forming a bridge. The circuit structure of the EMI filter (110) is not limited to the one illustrated. The circuit structure of the EMI filter (110) can be provided in various ways depending on the design.

[0098] The power factor correction circuit (120) can compensate for the power factor of AC power provided from the EMI filter (110). The power factor correction circuit (120) can provide power with the power factor compensated to the DC converter (130). The power factor correction circuit (120) can be provided as a circuit in which various elements are connected in parallel and / or series. For example, the power factor correction circuit (120) can include a plurality of electrolytic capacitors (Cpf1, Cpf2), an inductor (Lpf), a diode (Dpf), and a switching element (SW_pf). The switching element (SW_pf) can correspond to a transistor. The transistor can allow or block the flow of current depending on the application of voltage. The circuit structure of the power factor correction circuit (120) is not limited to the exemplified one. The circuit structure of the power factor correction circuit (120) can be provided in various ways depending on the design.

[0099] The DC converter (130) can convert the power output from the power factor correction circuit (120) into DC power. The DC converter (130) can transmit the converted DC power to the RF power supply (140). The DC converter (130) can be provided as a circuit in which various elements are connected in parallel and / or in series. For example, the DC converter (130) can include a switching element (SW_dc), an inductor (Ldc), and a diode (Ddc). The switching element (SW_dc) can correspond to a transistor. The circuit structure of the DC converter (130) is not limited to the example. The circuit structure of the DC converter (130) can be provided in various ways depending on the design.

[0100] The RF power supply unit (140) may be provided as a circuit including various elements for generating an RF signal. For example, the RF power supply unit (140) may include an electrolytic capacitor (Cpa11), a capacitor (Cpa12), a plurality of inductors (Lpa11, Lpa12), and a switching element (SW_pa). The electrolytic capacitor (Cpa11) may connect the Vpa node and the ground (GND). The switching element (SW_pa) and the inductor (Lpa11) may be connected in series between the Vpa node and the ground (GND). In addition, the inductor (Lpa12) and the capacitor (Cpa12) connected in series may be arranged between the N1 node connecting the switching element (SW_pa) and the inductor (Lpa11) and the impedance matching circuit (160).

[0101] The switching element (SW_pa) of the RF power supply (140) may be implemented as a transistor. The control unit (300) may control the switching element (SW_pa) to activate or deactivate the RF power supply (140). The control unit (300) may control the operation of the RF power supply (140) by adjusting the voltage applied to the switching element (SW_pa). When the switching element (SW_pa) is turned on, the operation of the RF power supply (140) may be activated. When the switching element (SW_pa) is turned off, the operation of the RF power supply (140) may be deactivated.

[0102] The switch (150) can be connected to the output terminal of the RF power supply (140). In addition, the first switch (SM) can be connected to the impedance matching circuit (160). The switch (150) can connect the impedance matching circuit (160) to the RF power supply (140).

[0103] The impedance matching circuit (160) may be provided as a circuit in which a plurality of inductors (L), a plurality of capacitors (C), and a plurality of switches are connected in series and / or in parallel. The plurality of switches included in the impedance matching circuit (160) may be opened or closed under the control of the control unit (300). As the plurality of switches are controlled, impedance matching may be performed. In FIG. 6, the impedance matching circuit (160) is illustrated as including three parallel-connected inductors (L), three parallel-connected capacitors (C), and nine switches, but is not limited thereto. The structure of the impedance matching circuit (160) may be variously changed depending on the design. The control unit (300) may control the impedance matching circuit (160) to match the output impedance of the RF power supply unit (140) and the electrode impedance of the electrode unit (170).

[0104] According to various embodiments, an inductor (Ldr) may be further included between the impedance matching circuit (160) and the electrode unit (170). The inductor (Ldr) may prevent sparks from occurring when RF power is provided from the impedance matching circuit (160) to the electrode unit (170).

[0105] The input signal variable part (180) can be implemented as a closed loop circuit in which one end is connected to the output terminal of the impedance matching circuit (160) and the other end is connected to the switching element (SW_pa) of the RF power supply part (140). The input signal variable part (180) can include a voltage sensor (181), a current sensor (182), a frequency control part (183), a peak detector (184), an oscillator (185) and / or a gate driver (186). The input signal variable part (180) can be implemented in a form in which some of the above-described components are omitted, and can further include other components necessary for identifying a target object and generating an input signal whose frequency is varied according to the identified target object.

[0106] The voltage sensor (181) is connected to the output terminal of the impedance matching circuit (160) and can detect the voltage transmitted from the RF power supply unit (140) through the impedance matching circuit (160) to the electrode unit (170).

[0107] The current sensor (182) can be connected in parallel with a resistor connected in series between the output terminal of the impedance matching circuit (160) and the input terminal of the electrode unit (170). The current sensor (182) can detect the current flowing from the RF power supply unit (140) through the impedance matching circuit (160) to the electrode unit (170) by measuring the voltage drop that occurs when the current output from the impedance matching circuit (160) passes through the resistor.

[0108] The frequency control unit (183) can be electrically connected to components of the input signal variable unit (180) and can control the components of the input signal variable unit (180). The frequency control unit (183) is connected at one end to a voltage sensor (181) and a current sensor (182) and can obtain information about voltage and current detected at the output terminal of the impedance matching circuit (160) from the voltage sensor (181) and the current sensor (182).

[0109] The frequency control unit (183) can detect the resonance point or the resonance frequency at the resonance point for each of the plurality of objects to be dried within the drum (20) based on the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode unit (170)). The frequency control unit (183) can determine whether the plurality of objects to be dried within the drum (20) are received based on the number of resonance points detected.

[0110] In addition, the frequency control unit (183) can detect the load characteristics of each of the plurality of drying objects accommodated in the drum (20) based on the phase difference between the voltage and current detected at the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode unit (170)). The frequency control unit (183) can classify the plurality of drying objects accommodated in the drum (20) into preset categories based on the load characteristics of each of the plurality of drying objects.

[0111] The frequency control unit (183) can detect an optimal frequency having the maximum drying efficiency for each of a plurality of objects to be dried classified into an upper category. Accordingly, the frequency control unit (183) can generate a PWM (Pulse Width Modulation) signal including optimal frequency information for each of the plurality of objects to be dried so that the RF power supply unit (140) can amplify the optimal RF power and apply it to the electrode unit (170).

[0112] The frequency control unit (183) may be implemented as a microcontroller. The frequency control unit (183) may include at least one frequency control unit processor and / or frequency control unit memory. The frequency control unit memory may include volatile memory (e.g., S-RAM, D-RAM) and non-volatile memory (e.g., ROM, EPROM). The frequency control unit processor and the frequency control unit memory may be implemented as separate chips or as a single chip. The frequency control unit processor may process various data and various signals using instructions, data, programs, and / or software stored in the frequency control unit memory. The frequency control unit processor may generate control signals for controlling components of the main input signal variable unit (180). The frequency control unit processor may include one core or may include multiple cores.

[0113] The frequency control unit (183) can perform the control operation according to the present disclosure performed by the control unit (300). The control unit (300) can also perform the control operation according to the present disclosure performed by the frequency control unit (183). The frequency control unit (193) can also be implemented as a single module with the control unit (300).

[0114] The peak detector (184) can receive a PWM signal from the frequency control unit (183) and detect the peak value of the PWM signal. The peak detector (184) can convert the peak value of the PWM signal of the transistor (51) into a DC voltage and transmit information about the DC voltage value to the oscillator (185).

[0115] The oscillator (185) can be implemented as a voltage controlled oscillator (VCO). The oscillator (185) can correct the frequency of the input signal (6) based on the error between the reference voltage and the peak value of the PWM signal of the transistor (51). That is, the oscillator (1054) can generate a changed frequency input signal using the voltage as an input value. Accordingly, an input signal having an optimal frequency according to the identified target object can be generated.

[0116] The oscillator (185) can output an input signal with a variable frequency to a gate driver (186) connected to the other end of the plurality of oscillators (185).

[0117] The gate driver (186) may have one end connected to the oscillator (185) and the other end connected to the switching element (SW_pa) of the RF power supply (140). The gate driver (186) may receive a variable input signal from the oscillator (185) and provide a high driving current required to quickly switch the switching element (SW_pa) of the RF power supply (140). Accordingly, the gate driver (186) may control the turn-on and turn-off of the power element and apply the received variable input signal in the form of a gate voltage applied to the gate terminal of the switching element (SW_pa).

[0118] Figure 7 is a graph measuring the gain value according to the frequency change by changing the drying material accommodated in the drum (20).

[0119] Referring to FIG. 11, this is a diagram showing a gain value according to the frequency of the input signal when only the first dry matter of a single category is accommodated in the drum (20) (G1), when only the second dry matter of a single category is accommodated in the drum (20) (G2), and when both the first and second dry matters are accommodated in the drum (20) (G3). In this case, the gain value may be a value obtained by dividing the output power detected at the output terminal of the impedance matching circuit (160) by the input power applied to the RF power supply unit (140).

[0120] At this time, the first object to be dried and the second object to be dried are objects to be dried that are classified into separate categories. That is, the load characteristics measured by the frequency control unit (183) may be different for the first object to be dried and the second object to be dried. In addition, since the electrical characteristics of the first object to be dried and the second object to be dried are different, the optimal frequency that produces the highest power efficiency may be different. For example, according to the graphs G1 and G2 illustrated in FIG. 11, since the first object to be dried has the maximum gain value at fA, the optimal frequency may be fA, and since the second object to be dried has the maximum gain value at fB, the optimal frequency may be fB. In other words, the objects to be dried that are classified into separate categories may have different frequency characteristics. Having different frequency characteristics may include that the frequencies at the resonance points are different.

[0121] According to Fig. 11, when the first and second objects to be dried are accommodated together in the drum (20), the frequency characteristics are such that the resonance points unique to each object to be dried (resonance points at fA and fB) appear, as shown in G3. In other words, when the first and second objects to be dried are accommodated together in the drum (20), the resonance points unique to each object to be dried appear independently, rather than the two resonance points causing interference.

[0122] Accordingly, the frequency control unit (183) detects a resonance point based on the voltage and current output from the output terminal of the impedance matching circuit (160), and when multiple resonance points are detected, it can be determined that multiple objects belonging to different categories are accommodated in the drum (20). That is, the frequency control unit (183) can be determined that multiple objects are accommodated based on frequency characteristics having unique resonance points according to the category of the objects.

[0123] FIG. 8 is a control flowchart of a dryer (1) for determining whether a plurality of drying materials are accommodated in a drum (20) according to one embodiment.

[0124] According to one embodiment, the frequency control unit (183) may apply initial power to the RF power supply unit (140) to determine the number of resonance points detected (1100). Applying the initial power may include operating the dielectric heating device (101) to supply power lower than the power for performing the drying process through dielectric heating. Since the initial power supply is for determining whether a plurality of objects to be dried are classified into different categories before initiating the drying process and detecting an optimal frequency for objects to be dried that are classified into different categories, unnecessary power consumption can be prevented by supplying power at a lower level than when performing the drying process.

[0125] The frequency control unit (183) can control the input signal variation unit (180) to vary the frequency of the input signal and apply the varied input signal as an input signal of the RF power supply unit (140) (1101). The frequency variation range of the input signal may be preset.

[0126] The frequency control unit (183) can detect a resonance point based on a gain value measured as the frequency of the input signal varies (1102). At this time, the resonance point may correspond to a point where the output power detected at the output terminal of the impedance matching circuit (160) is maximum compared to the input power applied to the RF power supply unit (140).

[0127] The frequency control unit (183) can determine whether there are multiple detected resonance points (1103).

[0128] If there is only one detected resonance point (No of 1103), the frequency control unit (183) can determine that only one object to be dried is accommodated in the drum (20) (1105). If the frequency control unit (183) determines that only one object to be dried is accommodated in the drum (20), the frequency control unit (183) can detect an optimal frequency for the object to be dried (1106). At this time, the optimal frequency is a frequency that provides the maximum drying efficiency in drying one object to be dried located in the drum (20), and may correspond to a resonance frequency. After detecting the optimal frequency for one object to be dried located in the drum (20), the frequency control unit (183) can perform a series of operations (1110 to 1112) described below with reference to FIG. 12 to generate an optimal frequency input signal and transmit it to the RF power supply unit (140).

[0129] On the other hand, if there are multiple detected resonance points (example of 1103), the frequency control unit (183) can determine that multiple objects to be dried are accommodated in the drum (20) (1104). If it is determined that multiple objects to be dried are accommodated in the drum (20), the frequency control unit (183) can determine the classification categories to which the multiple objects to be dried belong. Hereinafter, a method for classifying multiple objects to be dried by category will be described with reference to FIGS. 9 to 11.

[0130] Figures 9 to 11 are graphs showing the waveforms of voltage and current measured at the output terminal of the impedance matching circuit (160) according to the dry material accommodated in the drum (20).

[0131] According to one embodiment, in a dryer (1), the load applied to the elements constituting the dielectric heating device (101) (for example, the inductors (Lpa11, Lpa12) and / or capacitors (Cpa12) constituting the RF power supply unit (140)) may vary depending on the characteristics of the object to be dried contained in the drum. Accordingly, the phase difference of the voltage and current output from the output terminal of the impedance matching circuit (160) (i.e., the input terminal of the electrode unit (170)) may vary depending on the characteristics of the object to be dried contained in the drum. The frequency control unit (183) can identify the object to be dried contained in the drum (20) based on the phase difference of the voltage and current output from the output terminal of the impedance matching circuit (160).

[0132] At this time, depending on the characteristics of the object to be dried, the load applied to the dielectric heating device (101) may include at least one of a resistive load, an inductive load, or a capacitive load. Hereinafter, the phase difference of voltage and current according to each load will be described with reference to FIGS. 9 to 11.

[0133] When multiple items of drying are present in the drum (20), the frequency control unit (183) may include classifying the multiple items of drying into preset categories. The load characteristics for each category (e.g., clothing, shoes, bags, accessories, blankets, etc.) may be preset and stored in the frequency control unit memory or memory (320). Therefore, being classified into different categories may mean that the items of drying correspond to items of drying having different load characteristics.

[0134] Fig. 9 illustrates the phase difference between voltage and current according to a resistive load. As illustrated in Fig. 9, when a resistive load is applied to the dielectric heating device (101), the phase difference between voltage and current can be measured as 0. Accordingly, the frequency control unit (183) can determine that a resistive load is applied to the dielectric heating device (101) when the phase difference between voltage and current detected by the voltage sensor (181) and the current sensor (182) is 0.

[0135] That is, when the phase difference between voltage and current is 0, the frequency control unit (183) can determine that the object to be dried is located between the plurality of electrodes constituting the electrode unit (170) so as to have electrical characteristics when the electrode unit (170) is implemented as a resistive load (e.g., a simple resistor).

[0136] For example, since a resistive load has an electrical characteristic of converting energy into heat when current flows, a drying material that has the electrical characteristics when the electrode portion (170) is implemented as a resistive load (e.g., a simple resistor) may include a blanket that can have a high moisture content.

[0137] Accordingly, the frequency control unit (183) can classify the dry material received in the drum (20) into the blanket category when the phase difference between the voltage and current is 0.

[0138] Fig. 10 illustrates the phase difference between voltage and current according to an inductive load. As illustrated in Fig. 10, when an inductive load is applied to the dielectric heating device (101), changes in current relative to voltage may occur differently over time. That is, when an inductive load is applied to the dielectric heating device (101), the current waveform leads the voltage waveform due to its electrical characteristics. Accordingly, the phase difference of current relative to voltage (phase in Fig. 10) may be measured as a negative number. Accordingly, the frequency control unit (183) may determine that an inductive load is applied to the dielectric heating device (101) when the phase difference between voltage and current detected by the voltage sensor (181) and the current sensor (182) is negative.

[0139] That is, when the phase difference between voltage and current is negative, the frequency control unit (183) can determine that the object to be dried is located between the plurality of electrodes constituting the electrode unit (170) so as to have electrical characteristics when the electrode unit (170) is implemented as an inductive load (e.g., an inductor).

[0140] For example, since an inductive load has an electrical characteristic of generating a magnetic field when current flows, a target object that has the electrical characteristic when the electrode portion (170) is implemented as an inductive load (e.g., a coil) may include a component having a spiral shape like a coil (e.g., a key ring or buckle, etc.).

[0141] Accordingly, the frequency control unit (183) can classify the dried material received in the drum (20) into a bag or belt category when the phase difference between the voltage and current is negative.

[0142] Fig. 11 illustrates the phase difference between voltage and current according to a capacitive load. As illustrated in Fig. 11, when a capacitive load is applied to the dielectric heating device (101), changes in current relative to voltage may occur differently over time. That is, when a capacitive load is applied to the dielectric heating device (101), the voltage waveform leads the current waveform due to its electrical characteristics. Accordingly, the phase difference of current relative to voltage (phase in Fig. 11) can be measured as a positive number. Accordingly, the frequency control unit (183) can determine that a capacitive load is applied to the dielectric heating device (101) when the phase difference between voltage and current detected by the voltage sensor (181) and the current sensor (182) is positive.

[0143] That is, when the phase difference between voltage and current is positive, the frequency control unit (183) can determine that the object to be dried is located between the plurality of electrodes constituting the electrode unit (170) so as to have electrical characteristics when the electrode unit (170) is implemented as a capacitive load (e.g., a capacitor).

[0144] For example, since an inductive load has an electrical characteristic of storing and releasing electrical energy, a dry object that has the electrical characteristic when the electrode portion (170) is implemented as a capacitive load (e.g., a capacitor) may include a component having a form in which a metal is combined with a dielectric (e.g., a zipper that is wet with water).

[0145] Accordingly, the frequency control unit (183) can classify the dry material received in the drum (20) into a category of clothing with a zipper (e.g., outerwear such as padding) when the phase difference between the voltage and current is positive.

[0146] As described above with reference to FIGS. 9 to 11, since the load characteristics vary depending on the objects to be dried within the drum (20), the frequency control unit (183) can compare the phase difference of the detected voltage and current with the phase information stored in advance to determine the load characteristics of each of the plurality of objects to be dried, and can classify the objects to be dried into categories based on the load characteristics of each of the plurality of objects to be dried. The load characteristics and phase difference information for each category may be stored in the frequency control unit memory or the memory (320).

[0147] In the above, with reference to FIGS. 9 to 11, the principle of classifying the received drying materials into categories when multiple drying materials are received in the drum (20) has been described. Based on the above, with reference to FIG. 12, a method of controlling the dryer (10) for classifying the received drying materials into categories and applying optimal RF power to the electrode unit (170) for each drying material classified into a different category will be described.

[0148] FIG. 12 is a control flowchart of a dryer (1) for classifying a plurality of objects to be dried by category according to one embodiment and transmitting an optimal frequency input signal for each object to be dried by different categories to an RF power supply (140).

[0149] The frequency control unit (183) can measure the phase difference between voltage and current based on the voltage and current detected at the output terminal of the impedance matching circuit (160) as the variable input signal is applied to the RF power supply unit (140) (1107). The frequency control unit (183) can monitor the phase difference between voltage and current over time while performing a frequency sweep that changes the frequency of the input signal of the RF power supply unit (140) by controlling the input signal variable unit (180).

[0150] The frequency control unit (183) can compare the phase difference of the measured detected voltage and current with the phase information stored in advance to determine the load characteristics of each of the plurality of objects to be dried, and can classify each object to be dried by category based on the load characteristics of each of the plurality of objects to be dried (1108).

[0151] The frequency control unit (183) can detect the optimal frequency for each object belonging to a different category (1109). At this time, the optimal frequency for the object belonging to each classification category may correspond to the frequency at the resonant point where the dielectric heating device (101) operates most efficiently.

[0152] For example, if it is determined that the first and second dry objects described above in FIG. 7 are accommodated together in the drum (20), the frequency control unit (183) can detect that the optimal frequency for the first dry object is fA and the optimal frequency for the second dry object is fB.

[0153] The frequency control unit (183) can detect the optimal frequency for the object belonging to each classification category and apply the optimal RF power for the object belonging to each classification category to the electrode unit (170).

[0154] According to one embodiment, the frequency control unit (183) can control the input signal variable unit (180) to apply an optimal frequency input signal for the identified object to the RF power supply unit (140).

[0155] The frequency control unit (183) can generate a pulse signal corresponding to the optimal frequency for each of the objects classified into different categories (1110). At this time, the frequency control unit (183) transmits the generated pulse signal to a peak detector (184), and the peak detector (184) can detect the peak value of the received pulse signal and convert the detected peak value into a DC voltage. Thereafter, the peak detector (184) can transmit information about the converted DC voltage value to an oscillator (185).

[0156] Accordingly, the generator (185) can generate an input signal having an optimal frequency according to the identified object by using the converted DC voltage value corresponding to the pulse signal as an input value (1111).

[0157] The oscillator (185) can alternately apply the optimal frequency input signal for each of the drying materials classified into different categories in a time-division manner as an input signal of the RF power supply unit (140) (1112). Specifically, the oscillator (185) outputs the input signal with a variable frequency to the gate driver (186) connected to the other end of the plurality of oscillators (185), and the gate driver (186) can apply the input signal having the optimal frequency in the form of a gate voltage applied to the gate terminal of the switching element (SW_pa) of the RF power supply unit (140). The RF power supply unit (140) that receives the input signal having the optimal frequency as an input signal can apply the maximum power to the electrode unit (170). Accordingly, the drying efficiency can be increased.

[0158] In performing a drying operation by simultaneously accommodating objects with different frequency characteristics that can increase the drying efficiency in the drum (20), when a single RF power is applied to the electrode unit (170), a difference in the dryness between the objects may occur, and a problem may arise in which some objects are completely dried while other objects are not completely dried.

[0159] According to one embodiment, when a plurality of drying materials having different optimal frequency characteristics are simultaneously received in the drum (20) and a drying operation is performed, in order to maintain a uniform dryness, the frequency control unit (183) may alternately apply different optimal RF powers to the electrode unit (170) in a time-division manner. This will be described below with reference to FIGS. 13 to 16.

[0160] Fig. 13 is a control flowchart of a dryer (1) for supplying optimal RF power to each of the dry materials classified into different categories in a time-division manner according to one embodiment.

[0161] Fig. 14 is a drawing showing an operation timeline of a dryer (1) according to the control method of Fig. 13.

[0162] According to one embodiment, the frequency control unit (183) may alternately perform a drying process of applying RF power of different frequencies to the electrode unit (170) multiple times. At this time, alternately performing a drying process of applying RF power of different frequencies to the object to be dried multiple times may include applying RF power of a specific frequency to the electrode unit (170) for a preset time in a time-division manner. At this time, the total drying time may represent the sum of the drying times for each drying operation of applying RF power of a specific frequency to the object to be dried.

[0163] Specifically, the frequency control unit (183) can detect the optimal frequency for the object to be dried belonging to each classification category (1104 in FIG. 12), and then control the impedance matching circuit (160) to perform impedance matching on the first object to be dried among the plurality of objects to be dried (1201). Performing impedance matching on the first object to be dried may include matching the electrode impedance according to the electrical characteristics of the first object to be dried when the first object to be dried among the plurality of objects to be dried is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing impedance matching according to the electrical characteristics of the first object to be dried.

[0164] The frequency control unit (183) can control the input signal variable unit (180) to apply the optimal frequency signal of the first target object as an input signal of the RF power supply unit (140) for a time period T1 (e.g., T1 of FIG. 14) (1202). At this time, the input signal can be applied in the form of a gate voltage applied to the gate terminal of a switching element (SW_pa) implemented as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0165] The T1 time may be a preset drying time for the first object to be dried, and may be stored in the frequency control unit memory. Accordingly, the frequency control unit (183) may obtain information about the T1 time corresponding to the first object to be dried from the frequency control unit memory based on the determination that the first object to be dried is included among the plurality of objects to be dried. Thereafter, the frequency control unit (183) may generate an optimal frequency signal for the first object to be dried during the T1 time, and apply the generated signal as an input signal to the RF power supply unit (140).

[0166] Thereafter, the frequency control unit (183) may perform impedance matching on the second object of drying (1203). As described above, the second object of drying may correspond to an object of drying that is determined to be classified into a different category from the first object of drying among the plurality of objects of drying. Performing impedance matching on the second object of drying may include matching the electrode impedance according to the electrical characteristics of the second object of drying when the second object of drying is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing impedance matching according to the electrical characteristics of the second object of drying.

[0167] At this time, the frequency control unit (183) can control the switch (150) to short-circuit the RF power supply unit (140) and the impedance matching circuit (160) before performing impedance matching for the second object to be dried. Accordingly, the power supply from the RF power supply unit (140) to the electrode unit (170) is cut off, ensuring safety, and enabling accurate measurement and adjustment of the electrode impedance. Thereafter, the frequency control unit (183) can control the switch (150) to connect the RF power supply unit (140) and the impedance matching circuit (160) before completing impedance matching for the second object to be dried and applying the optimal frequency RF power of the second object to the electrode unit (170).

[0168] The frequency control unit (183) can apply the optimal frequency signal of the second object to the input signal of the RF power supply unit (140) for a time period T2 (e.g., T2 in FIG. 14) (1204). At this time, the input signal can be applied in the form of a gate voltage applied to the gate terminal of a switching element (SW_pa) implemented as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0169] The T2 time is a preset drying time for the second object to be dried, and may be stored in the frequency control unit memory. The T2 time may be the same as or different from the T1 time. Accordingly, the frequency control unit (183) may obtain information about the T2 time corresponding to the second object to be dried from the frequency control unit memory based on the determination that the second object to be dried is included among the plurality of objects to be dried. Thereafter, the frequency control unit (183) may generate an optimal frequency signal for the second object to be dried during the T2 time, and apply the generated signal as an input signal to the RF power supply unit (140).

[0170] The frequency control unit (183) can control the switch (150) to short-circuit the RF power supply unit (140) and the impedance matching circuit (160) after applying the optimal RF power to the second object to be dried for a time T2, and can control the impedance matching circuit (160) to perform impedance matching for the first object to be dried. Thereafter, the frequency control unit (183) can alternately provide the optimal RF power for the object to be dried belonging to each classification category to the electrode unit (170) as illustrated in FIG. 14. At this time, impedance matching can be performed while performing the drying operation by alternately providing different RF powers to the electrode unit (170).

[0171] Fig. 15 is a control flowchart of a dryer (1) for supplying optimal RF power to each of the dry materials classified into different categories in a time-division manner according to another embodiment.

[0172] Fig. 16 is a drawing showing an operation timeline of a dryer (1) according to the control method of Fig. 15.

[0173] According to another embodiment, the frequency control unit (183) may determine the dryness of the objects belonging to each classification category and apply the optimal RF power to the electrode unit (170) alternately in a time-division manner for the objects belonging to each classification category, and may apply the optimal RF power only to the objects belonging to the classification category that are determined to be incompletely dried to the electrode unit (170).

[0174] According to another embodiment, the frequency control unit (183) may alternately perform a drying process in which RF power of different frequencies is applied to the object to be dried multiple times. In this case, alternately performing a drying process in which RF power of different frequencies is applied to the object to be dried multiple times may include applying RF power of a specific frequency to the electrode unit (170) for a preset time in a time-division manner. In this case, the total drying time may represent the sum of the drying times for each drying operation in which RF power of a specific frequency is applied to the object to be dried.

[0175] The frequency control unit (183) can perform steps 1201 to 1204 of FIG. 13 to alternately perform a drying process of applying RF power of different frequencies to the object to be dried multiple times.

[0176] According to another embodiment, the frequency control unit (183) generates an optimal frequency signal for the second object to be dried for a time period of T2 and applies the signal as an input signal to the RF power supply unit (1204 in FIG. 13), and then determines the drying degree of the second object to be dried based on the electrode impedance of the second object to be dried (1205). As the drying of the object to be dried progresses, moisture contained in the object to be dried is removed, so that the impedance can be detected to gradually increase. In other words, as the drying progresses, the difference between the magnitude of the voltage detected by the electrode unit (170) and the magnitude of the reference voltage can gradually decrease.

[0177] The frequency control unit (183) can determine the dryness of the second object to be dried based on a change in the magnitude of the voltage detected at the output terminal of the impedance matching circuit (160) and / or a change in the electrode impedance. At this time, the detected electrode impedance is the electrode impedance after performing impedance matching on the second object to be dried (1203), so the dryness of the second object to be dried can be determined based on a change in the electrode impedance detected at the output terminal of the impedance matching circuit (160).

[0178] The frequency control unit (183) can determine the amount of water (i.e., moisture content) contained in the second object to be dried based on the detected electrode impedance. The frequency control unit (183) can determine whether the drying of the second object to be dried is complete based on whether the dryness of the second object to be dried reaches a tolerance range of a predetermined reference dryness level (1206).

[0179] If the frequency control unit (183) determines that the drying of the second object to be dried is not completed (NO of 1206), the control unit returns to step 1201 and alternately applies the optimal RF power for the first object to be dried and the second object to the electrode unit (170) in a time-division manner, thereby continuing the drying process.

[0180] On the other hand, when the frequency control unit (183) determines that drying of the second object to be dried is completed (example of 1206), it can stop applying the optimal RF power for the second object to be dried to the electrode unit (170) and apply only the optimal RF power for the first object to be dried to the electrode unit (170). That is, based on the determination that drying of the second object to be dried is completed in FIG. 16, only the optimal RF power for the first object to be dried can be applied to the electrode unit (170) after the time point Tm.

[0181] Specifically, the frequency control unit (183) can control the impedance matching circuit (160) to perform impedance matching for the first object among the plurality of objects to be dried in order to apply only the optimal RF power for the first object to the electrode unit (170) (1207). Performing impedance matching for the first object may include matching the electrode impedance according to the electrical characteristics of the first object among the plurality of objects to be dried when it is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing impedance matching according to the electrical characteristics of the first object to be dried.

[0182] The frequency control unit (183) can control the input signal variable unit (180) to apply the optimal frequency signal of the first object as an input signal of the RF power supply unit (140) (1208). At this time, the input signal can be applied in the form of a gate voltage applied to the gate terminal of a switching element (SW_pa) implemented as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0183] At this time, unlike 1202, the frequency control unit (183) can apply the optimal frequency signal of the first dry object as an input signal of the RF power supply unit (140) without time constraints.

[0184] After that, the frequency control unit (183) can determine the drying degree of the second drying object based on the electrode impedance for the second drying object (1209).

[0185] The frequency control unit (183) can determine the dryness of the first object to be dried based on a change in the magnitude of the voltage detected at the output terminal of the impedance matching circuit (160) and / or a change in the electrode impedance. At this time, the detected electrode impedance is the electrode impedance after performing impedance matching on the first object to be dried (1207), so the dryness of the first object to be dried can be determined based on a change in the electrode impedance detected at the output terminal of the impedance matching circuit (160).

[0186] The frequency control unit (183) can determine the amount of water (i.e., moisture content) contained in the first drying object based on the detected electrode impedance. The frequency control unit (183) can determine whether the drying of the second drying object is complete based on whether the dryness of the second drying object reaches a tolerance range of a predetermined reference dryness level (1210).

[0187] If the frequency control unit (183) determines that the drying of the first object to be dried is not completed (NO of step 1210), the unit returns to step 1208 and applies the optimal RF power for the second object to the electrode unit (170), thereby continuing the drying process for the first object to be dried.

[0188] On the other hand, when the frequency control unit (183) determines that drying of the first drying object is completed (example of 1210), it can determine that drying of the plurality of drying objects accommodated in the drum (20) is completed and end the drying process.

[0189] In the present disclosure, a case in which a plurality of objects to be dried are accommodated in a drum (20) are classified into two categories is described as an example, but the same control operation can be performed even when a plurality of objects to be dried are accommodated in a drum (20) are classified into three or more categories.

[0190] Meanwhile, when the drying process is performed, the control unit (300) may control the motor (72) to rotate the drum (20). At this time, unlike when the drying process is started, overlapping of the objects to be dried may occur due to the rotation of the drum (20). In order to increase the drying efficiency when drying objects using dielectric heating, a certain distance between the objects to be dried is required. If the objects to be dried overlap and the objects to be dried are spaced apart, the frequency characteristics may change due to impedance interference between them, which may reduce the drying efficiency. Therefore, in order to maintain high drying efficiency, it is necessary to determine the overlapping of the objects to be dried while the drying process is performed and to separate the objects to eliminate the overlapping.

[0191] Referring to FIGS. 17 and 18 below, a method for confirming overlapping of a drying object and resolving the overlapping will be described.

[0192] Figure 17 is a drawing for explaining the change in the gain value according to the overlapping of the drying object as the drying process is performed.

[0193] Referring to FIG. 17, a graph (G3) is a drawing showing a gain value according to the frequency of an input signal before the drying process starts when the first and second objects to be dried are accommodated together in the drum (20), and a graph (G4) is a drawing showing a gain value according to the frequency of an input signal that changes as the drying process is performed when the first and second objects to be dried are accommodated together in the drum (20). In this case, the gain value may be a value obtained by dividing the output power detected at the output terminal of the impedance matching circuit (160) by the input power applied to the RF power supply (140). As described above, the first and second objects to be dried are objects classified into separate categories.

[0194] According to Fig. 17, when the first and second objects to be dried are accommodated together in the drum (20), before the drying process begins (i.e., before the drum (20) rotates), the frequency characteristics of each object to be dried (resonance points at fA and fB) appear, as shown in G3. In other words, when the first and second objects to be dried are accommodated together in the drum (20), the two resonance points do not interfere, but the resonance points of each object to be dried appear independently.

[0195] On the other hand, after the drying process is initiated (i.e., after rotation of the drum (20) occurs), the resonance points unique to each object to be dried (resonance points at fA and fB) do not all appear as shown in G4, and a new resonance point (resonance point at fA+B) may appear due to impedance interference caused by the overlapping phenomenon of the objects to be dried.

[0196] Accordingly, the frequency control unit (183) can determine that an overlapping phenomenon of the objects has occurred when the resonance points unique to each object (resonance points at fA and fB) do not appear and a new resonance point (resonance point at fA+B) is detected.

[0197] Fig. 18 is a drawing showing an example of an overlapping removal process of a dryer (1) to remove the overlapping phenomenon of a drying object.

[0198] The main reason for the overlapping phenomenon of the drying materials is that the drying materials tumbling as the drum (20) continues to rotate by the motor (72) during the drying process. When the motor (72) is driven at high rpm to rotate the drum (20), the drying process can be performed with the drying materials continuously overlapping.

[0199] Accordingly, when the frequency control unit (183) determines that an overlapping phenomenon of the objects to be dried has occurred, the overlapping phenomenon of the objects to be dried can be resolved by controlling the motor (72) so that the drum (20) rotates for half a cycle and then stops. At this time, the rotation of the drum (20) for one cycle (Tp) may include the time it takes for any point on the inner surface of the drum (20) to rotate from the lowest point back to the lowest point, and the rotation of the drum (20) for half a cycle (Tp / 2) may include the time it takes for any point on the inner surface of the drum (20) to rotate from the lowest point to the highest point.

[0200] For example, as illustrated in Fig. 17, when the overlapping objects are located at the lowest point of the drum (20), the frequency control unit (183) can control the motor (72) to rotate the drum (20) in the d1 direction for half a cycle. Accordingly, the objects can be located at the highest point of the drum (20). The frequency control unit (183) can stop the operation of the motor (72) after rotating the drum (20) in the d1 direction for half a cycle, thereby stopping the rotation of the drum (20). Accordingly, the objects to be dried when the drum (20) is located at the highest point can have the overlapping phenomenon resolved by free falling from the highest point to the lowest point of the drum (20).

[0201] The operation control of the motor (72) by the aforementioned frequency control unit (183) can be performed by the control unit (300) of the dryer (1).

[0202] The rotation control of the drum (20) of the present disclosure is an example of an overlapping resolution process for resolving the overlapping phenomenon of the object to be dried. Any operation that can resolve the overlapping of the object to be dried when performing the drying process can be adopted as an example of an overlapping resolution process.

[0203] According to one embodiment, in order to ensure high drying efficiency, a plurality of objects to be dried having different optimal frequency characteristics are simultaneously placed in a drum (20) and a drying operation is performed. During the process, whether or not the objects to be dried overlaps is monitored and an overlapping removal process can be performed. This will be described below with reference to FIGS. 19 to 22.

[0204] FIG. 19 is a control flowchart of a dryer (1) for eliminating the overlapping phenomenon of objects to be dried in supplying optimal RF power to each object to be dried classified into different categories in a time-division manner according to one embodiment.

[0205] Fig. 20 is a drawing showing an operation timeline of a dryer (1) according to the control method of Fig. 19.

[0206] According to one embodiment, the frequency control unit (183) may determine whether overlapping of objects has occurred prior to performing impedance matching (1301). Specifically, the frequency control unit (183) may determine whether overlapping of objects has occurred based on the detection of a new resonance point while the unique resonance point of each object classified into a different category is not detected.

[0207] If it is determined that an overlapping phenomenon of the drying material has occurred, the frequency control unit (183) may perform an overlapping resolution process before performing impedance matching (1302). The frequency control unit (183) may control various components of the dryer (1) to perform the overlapping resolution process. For example, as described with reference to FIG. 18, the motor (72) may be controlled to rotate and stop the drum (20) in half a cycle.

[0208] The frequency control unit (183) can control the impedance matching circuit (160) to perform impedance matching on the first object to be dried among the plurality of objects to be dried after determining that overlapping of the objects to be dried has not occurred (No in 1301) or after performing an overlapping resolution process even if overlapping of the objects to be dried has occurred (1303). Performing impedance matching on the first object to be dried at 1303 may correspond to the impedance matching on the first object to be dried at 1201. That is, performing impedance matching on the first object to be dried may include matching the electrode impedance according to the electrical characteristics of the first object to be dried among the plurality of objects to be dried when it is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing impedance matching to suit the electrical characteristics of the first target object.

[0209] The frequency control unit (183) can control the input signal variable unit (180) to apply the optimal frequency signal of the first object to be dried as an input signal of the RF power supply unit (140) during a time T1 (e.g., T1 of FIG. 20) (1304). Applying the optimal frequency signal for the first object to be dried as an input signal of the RF power supply unit (140) at 1304 may correspond to applying the optimal frequency signal for the first object to the input signal of the RF power supply unit (140) at 1202. That is, the input signal can be applied in the form of a gate voltage applied to a gate terminal of a switching element (SW_pa) implemented as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0210] The T1 time may be a preset drying time for the first object to be dried, and may be stored in the frequency control unit memory. Accordingly, the frequency control unit (183) may obtain information about the T1 time corresponding to the first object to be dried from the frequency control unit memory based on the determination that the first object to be dried is included among the plurality of objects to be dried. Thereafter, the frequency control unit (183) may generate an optimal frequency signal for the first object to be dried during the T1 time, and apply the generated signal as an input signal to the RF power supply unit (140).

[0211] The frequency control unit (183) can determine whether overlapping of the objects has occurred after applying the optimal RF power for the first object to the electrode unit (170) (1304). Specifically, the frequency control unit (183) can determine whether overlapping of the objects has occurred based on the detection of a new resonance point while the unique resonance point of each object classified into a different category is not detected.

[0212] If it is determined that an overlapping phenomenon of the drying material has occurred, the frequency control unit (183) may perform an overlapping resolution process before performing impedance matching (1305). The frequency control unit (183) may control various components of the dryer (1) to perform the overlapping resolution process. For example, as described with reference to FIG. 18, the motor (72) may be controlled to rotate and stop the drum (20) in half a cycle.

[0213] Thereafter, the frequency control unit (183) may perform impedance matching on the second object of drying (1306). As described above, the second object of drying may correspond to an object of drying that is determined to be classified into a different category from the first object of drying among the plurality of objects of drying. Performing impedance matching on the second object of drying at 1306 may correspond to the impedance matching on the second object of drying at 1203. That is, performing impedance matching on the second object of drying may include matching the electrode impedance according to the electrical characteristics of the second object of drying when the second object of drying is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing impedance matching according to the electrical characteristics of the second object of drying.

[0214] At this time, the frequency control unit (183) can control the switch (150) to short-circuit the RF power supply unit (140) and the impedance matching circuit (160) before performing impedance matching for the second object to be dried. Accordingly, the power supply from the RF power supply unit (140) to the electrode unit (170) is cut off, ensuring safety, and enabling accurate measurement and adjustment of the electrode impedance. Thereafter, the frequency control unit (183) can control the switch (150) to connect the RF power supply unit (140) and the impedance matching circuit (160) before completing impedance matching for the second object to be dried and applying the optimal frequency RF power of the second object to the electrode unit (170).

[0215] The frequency control unit (183) can apply the optimal frequency signal of the second object to the input signal of the RF power supply unit (140) during time T2 (e.g., T2 in FIG. 20) (1307). Applying the optimal frequency signal for the second object to the input signal of the RF power supply unit (140) at 1307 may correspond to applying the optimal frequency signal for the second object to the input signal of the RF power supply unit (140) at 1204. That is, the input signal may be applied in the form of a gate voltage applied to the gate terminal of a switching element (SW_pa) implemented with an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0216] The T2 time is a preset drying time for the second object to be dried, and may be stored in the frequency control unit memory. The T2 time may be the same as or different from the T1 time. Accordingly, the frequency control unit (183) may obtain information about the T2 time corresponding to the second object to be dried from the frequency control unit memory based on the determination that the second object to be dried is included among the plurality of objects to be dried. Thereafter, the frequency control unit (183) may generate an optimal frequency signal for the second object to be dried during the T2 time, and apply the generated signal as an input signal to the RF power supply unit (140).

[0217] The frequency control unit (183) may apply the optimal RF power to the second object to be dried for a time period of T2, and then determine whether the objects to be dried are overlapped again. If it is determined that the objects to be dried are overlapped, an overlapping removal process may be performed. Thereafter, as illustrated in FIG. 14, the frequency control unit (183) may alternately provide the optimal RF power for the objects to be dried belonging to each classification category to the electrode unit (170). At this time, while performing the drying operation by alternately providing different RF powers to the electrode unit (170), the object overlapping removal process and impedance matching may be performed.

[0218] Fig. 21 is a control flowchart of a dryer (1) for eliminating the overlapping phenomenon of objects to be dried in supplying optimal RF power to each object to be dried classified into different categories in a time-division manner according to another embodiment.

[0219] Fig. 22 is a drawing showing an operation timeline of a dryer (1) according to the control method of Fig. 21.

[0220] According to another embodiment, the frequency control unit (183) may determine the dryness of the objects belonging to each classification category and apply the optimal RF power to the electrode unit (170) alternately in a time-division manner for the objects belonging to each classification category, and may apply the optimal RF power only to the objects belonging to the classification category that are determined to be incompletely dried to the electrode unit (170).

[0221] According to another embodiment, the frequency control unit (183) may determine the dryness of the second object to be dried based on the electrode impedance of the second object to be dried (1308). At this time, determining the dryness of the second object to be dried based on the electrode impedance of the second object to be dried at 1308 may correspond to determining the dryness of the second object to be dried at 1205. As the drying of the second object to be dried progresses, moisture contained in the object to be dried is removed, and thus the impedance may be detected to gradually increase. In other words, as the drying progresses, the difference between the magnitude of the voltage detected by the electrode unit (170) and the magnitude of the reference voltage may gradually decrease.

[0222] The frequency control unit (183) can determine the dryness of the second object to be dried based on a change in the magnitude of the voltage detected at the output terminal of the impedance matching circuit (160) and / or a change in the electrode impedance. At this time, the detected electrode impedance is the electrode impedance after performing impedance matching on the second object to be dried (1306), so the dryness of the second object to be dried can be determined based on a change in the electrode impedance detected at the output terminal of the impedance matching circuit (160).

[0223] The frequency control unit (183) can determine the amount of water (i.e., moisture content) contained in the second object to be dried based on the detected electrode impedance. The frequency control unit (183) can determine whether the drying of the second object to be dried is complete based on whether the dryness of the second object to be dried reaches a tolerance range of a predetermined reference dryness level (1309).

[0224] If the frequency control unit (183) determines that the drying of the second object to be dried is not completed (NO of 1309), the control unit returns to step 1301 and alternately applies the optimal RF power for the first object to be dried and the second object to the electrode unit (170) in a time-division manner, thereby continuing the drying process.

[0225] On the other hand, when the frequency control unit (183) determines that drying of the second object to be dried is completed (example of 1309), it may stop applying the optimal RF power for the second object to be dried to the electrode unit (170) and apply only the optimal RF power for the first object to be dried to the electrode unit (170). That is, based on the determination that drying of the second object to be dried is completed in FIG. 16, only the optimal RF power for the first object to be dried may be applied to the electrode unit (170) after the time point Tm.

[0226] At this time, the frequency control unit (183) can determine whether overlapping of the objects to be dried has occurred before applying only the optimal RF power for the first object to the electrode unit (170) (1310). Specifically, the frequency control unit (183) can determine whether overlapping of the objects to be dried has occurred based on the detection of a new resonance point while the unique resonance point of each object to be dried classified into different categories is not detected.

[0227] If it is determined that an overlapping phenomenon of the drying material has occurred, the frequency control unit (183) may perform an overlapping resolution process before performing impedance matching (1311). The frequency control unit (183) may control various components of the dryer (1) to perform the overlapping resolution process. For example, as described with reference to FIG. 18, the motor (72) may be controlled to rotate and stop the drum (20) in half a cycle.

[0228] Thereafter, the frequency control unit (183) may control the impedance matching circuit (160) to perform impedance matching on the first object among the plurality of objects to be dried in order to apply only the optimal RF power for the first object to the electrode unit (170) (1312). Performing the impedance matching on the first object at 1312 may correspond to performing the impedance matching at 1207. That is, performing the impedance matching on the first object may include matching the electrode impedance according to the electrical characteristics of the first object among the plurality of objects when it is positioned between the plurality of electrodes of the electrode unit (170) and the output impedance of the RF power supply unit (140). In other words, it may include performing the impedance matching according to the electrical characteristics of the first object.

[0229] The frequency control unit (183) can control the input signal variable unit (180) to apply the optimal frequency signal of the first object to be dried as an input signal of the RF power supply unit (140) (1313). Applying the optimal frequency signal of the first object to be dried as an input signal of the RF power supply unit (140) at 1313 may correspond to applying the optimal frequency signal of the first object to be dried as an input signal of the RF power supply unit (140) at 1208. That is, the input signal may be applied in the form of a gate voltage applied to a gate terminal of a switching element (SW_pa) implemented as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0230] At this time, unlike 1202, the frequency control unit (183) can apply the optimal frequency signal of the first dry object as an input signal of the RF power supply unit (140) without time constraints.

[0231] After that, the frequency control unit (183) can determine the dryness of the second dry object based on the electrode impedance for the second dry object (1314).

[0232] The frequency control unit (183) can determine the dryness of the first object to be dried based on a change in the magnitude of the voltage detected at the output terminal of the impedance matching circuit (160) and / or a change in the electrode impedance. At this time, the detected electrode impedance is the electrode impedance after performing impedance matching on the first object to be dried (1312), so the dryness of the first object to be dried can be determined based on a change in the electrode impedance detected at the output terminal of the impedance matching circuit (160).

[0233] The frequency control unit (183) can determine the amount of water (i.e., moisture content) contained in the first drying object based on the detected electrode impedance. The frequency control unit (183) can determine whether the drying of the second drying object is complete based on whether the dryness of the second drying object reaches a tolerance range of a predetermined reference dryness level (1315).

[0234] If the frequency control unit (183) determines that the drying of the first object to be dried is not completed (NO of 1315), it returns to 1313 and applies the optimal RF power for the second object to the electrode unit (170), thereby allowing the drying process for the first object to be dried to continue.

[0235] On the other hand, if the frequency control unit (183) determines that drying of the first drying object is completed (example of 1315), it can determine that drying of the plurality of drying objects accommodated in the drum (20) is completed and end the drying process.

[0236] In the present disclosure, a case in which a plurality of objects to be dried are accommodated in a drum (20) are classified into two categories is described as an example, but the same control operation can be performed even when a plurality of objects to be dried are accommodated in a drum (20) are classified into three or more categories.

[0237] According to another embodiment, in performing a drying process while alternately providing optimal RF power for objects belonging to each classification category to the electrode unit (170), high drying efficiency can be ensured by monitoring whether objects are overlapping and periodically performing a process to eliminate overlapping objects.

[0238] According to one embodiment, a dryer (1) may include: a drum (20); an electrode unit (170) including a plurality of electrodes (170a, 170b) spaced apart from each other along an outer surface of the drum (20); an RF power supply unit (140) including a switching element (SW_Pa) that receives an input signal and amplifies the input signal to generate RF power applied to the electrode unit (170); an impedance matching circuit (160) that performs impedance matching between the RF power supply unit (140) and the electrode unit (170); and an input signal variable unit (180) that classifies the plurality of objects to be dried according to preset categories based on the determination that the plurality of objects to be dried are accommodated in the drum (20), and generates an optimal frequency input signal for each of the objects to be dried classified into different categories alternately in a time-division manner based on the classification of the plurality of objects to be dried into different categories, and transmits the optimal frequency input signal to the switching element (SW_Pa).

[0239] The above input signal variable part (180) may include a voltage sensor (181) that detects a voltage output from an output terminal of the impedance matching circuit (160) as the frequency of the input signal received by the switching element (SW_Pa) is varied within a preset range, a current sensor (182) that detects a current output from an output terminal of the impedance matching circuit (160), and a frequency control part (183) that detects a resonance point for each of the plurality of objects to be dried or a resonance frequency at the resonance point based on the detected voltage and the detected current.

[0240] The frequency control unit (183) can determine that an overlapping phenomenon of the plurality of objects to be dried has occurred based on the fact that a resonance point is not detected for each of the plurality of objects to be dried and a resonance point is detected at a frequency other than the resonance frequency for each of the plurality of objects to be dried.

[0241] The dryer (1) further includes a motor (72) that provides driving force for rotating the drum (20), and the frequency control unit (183) can control the motor (72) to perform a process for eliminating the overlapping phenomenon while alternately transmitting an optimal frequency input signal for each of the items to be dried classified into the different categories to the switching element (SW_Pa) in a time-division manner based on the determination that the overlapping phenomenon has occurred.

[0242] The frequency control unit (183) can control the motor (72) to rotate the drum (20) semi-periodically and stop the rotation of the drum (20) in order to eliminate the overlapping phenomenon of the plurality of objects to be dried.

[0243] The frequency control unit (183) can determine that a plurality of objects to be dried are accommodated in the drum (20) based on the detection of a plurality of resonance points.

[0244] The frequency control unit (183) can detect the phase difference between the detected voltage and the detected current based on the determination that a plurality of objects to be dried are accommodated in the drum (20), and can determine the load characteristics of each of the plurality of objects to be dried in the drum (20) based on the phase difference.

[0245] The frequency control unit (183) includes a frequency control unit memory that includes information on load characteristics by preset category, and the frequency control unit (183) can classify the plurality of dry items according to preset categories by comparing the load characteristics of each of the plurality of dry items in the drum (20) with the load characteristics by category stored in the frequency control unit (183) memory.

[0246] The frequency control unit (183) can detect an optimal frequency for each of the dry goods classified into different categories based on the classification of the plurality of dry goods into different categories.

[0247] The optimal frequency for each of the above-mentioned objects classified into the different categories may be the resonance frequency at the resonance point for each of the above-mentioned objects.

[0248] The frequency control unit (183) can generate a pulse width modulation (PWM) signal for the optimal frequency for each of the detected dry materials classified into the different categories.

[0249] The above input signal variable part (180) may further include an oscillator (185) that generates an optimal frequency input signal for each of the objects classified into the different categories by using a DC voltage value corresponding to the pulse width modulation from the frequency control part (183) as an input value.

[0250] A control method of a dryer (1) including an electrode unit (170) including a plurality of electrodes spaced apart along an outer surface of a drum (20) according to one embodiment, an RF power supply unit (140) including a switching element (SW_Pa) receiving an input signal and amplifying the input signal to generate RF power applied to the electrode unit (170), an impedance matching circuit (160) performing impedance matching between the RF power supply unit and the electrode unit (170), and an input signal varying unit (180) varying the frequency of an input signal input to the switching element (SW_Pa) is provided, the method comprising: detecting an output voltage and an output current of an output terminal of the impedance matching circuit (160), determining whether a plurality of objects to be dried in the drum (20) are received based on the output voltage and the output current, and classifying the plurality of objects to be dried in the drum (20) according to a preset category based on the determination that the plurality of objects to be dried are received, and determining whether the plurality of objects to be dried are classified into different categories It may include generating an optimal frequency input signal for each of the dry objects classified into the different categories alternately based on the time division, and transmitting the optimal frequency input signal to the switching element (SW_Pa).

[0251] Determining whether a plurality of objects to be dried within the drum (20) is accommodated may include detecting a resonance point and a resonance frequency at the resonance point based on the output voltage and the output current, and determining that a plurality of objects to be dried within the drum (20) are accommodated based on the detection of a plurality of resonance points.

[0252] The control method of the above dryer (1) may further include determining that an overlapping phenomenon of the plurality of objects to be dried has occurred based on the detection of a resonance point at a frequency other than the resonance frequency of each of the plurality of objects to be dried, without detecting a resonance point for each of the plurality of objects to be dried.

[0253] The control method of the above dryer (1) may further include controlling a motor (72) that rotates the drum (20) to perform a process for eliminating the overlapping phenomenon while alternately transmitting an optimal frequency input signal for each of the items to be dried classified into the different categories to the switching element (SW_Pa) in a time-division manner based on the determination that the overlapping phenomenon has occurred.

[0254] Performing an operation to resolve the above-mentioned overlapping phenomenon may include controlling the motor (72) to rotate the drum (20) semi-periodically and stop the rotation of the drum (20).

[0255] Classifying the above multiple dry items according to preset categories is as follows:

[0256] It may include detecting a phase difference between the output voltage and the output current, determining a load characteristic of each of the plurality of objects to be dried in the drum (20) based on the phase difference, and comparing the load characteristic of each of the plurality of objects to be dried in the drum (20) with the category-specific load characteristic stored in the memory of the frequency control unit (183) to classify the plurality of objects to be dried in accordance with a preset category.

[0257] Generating an optimal frequency input signal for each of the objects classified into the different categories may include detecting an optimal frequency for each of the objects classified into the different categories based on the classification of the plurality of objects into the different categories, generating a pulse width modulation (PWM) signal for the optimal frequency for each of the objects classified into the different categories detected, and generating an optimal frequency input signal applied to the switching element (SW_Pa) based on the pulse width modulation (PWM) signal for the optimal frequency.

[0258] Detecting the optimal frequency for each of the above-described objects classified into the different categories may include detecting the resonant frequency at the resonance point for each of the objects as the optimal frequency.

[0259] Meanwhile, the disclosed embodiments may be implemented in the form of a storage medium storing computer-executable instructions. The instructions may be stored in the form of program code, and when executed by a processor, may generate program modules to perform the operations of the disclosed embodiments.

[0260] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0261] The methods according to various embodiments disclosed in this document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. 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 online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) 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., a downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0262] The disclosed embodiments have been described with reference to the attached drawings as described above. Those skilled in the art will understand that the present invention can be implemented in forms other than the disclosed embodiments without altering the technical spirit or essential features of the present invention. The disclosed embodiments are illustrative and should not be construed as limiting.

Claims

1. Drum; An electrode section including a plurality of electrodes spaced apart along the outer surface of the drum; An RF power supply unit including a switching element that receives an input signal and amplifies the input signal to generate RF power applied to the electrode unit; An impedance matching circuit that performs impedance matching between the RF power supply unit and the electrode unit; and A dryer comprising an input signal variable section that classifies a plurality of objects to be dried into preset categories based on the determination that a plurality of objects to be dried are accommodated in the drum, and generates an optimal frequency input signal for each object to be dried into the different categories alternately in a time-division manner based on the classification of the plurality of objects to be dried into different categories, and transmits the signal to the switching element.

2. In paragraph 1, The above input signal variable part; A dryer comprising a voltage sensor that detects a voltage output from an output terminal of the impedance matching circuit by varying the frequency of an input signal received by the switching element within a preset range, a current sensor that detects a current output from an output terminal of the impedance matching circuit, and a frequency control unit that detects a resonance point for each of the plurality of objects to be dried or a resonance frequency at the resonance point based on the detected voltage and the detected current.

3. In paragraph 2, The above frequency control unit, A dryer that determines that an overlapping phenomenon of the plurality of objects to be dried has occurred based on the fact that a resonance point is not detected for each of the plurality of objects to be dried, and a resonance point is detected at a frequency other than the resonance frequency for each of the plurality of objects to be dried.

4. In paragraph 3, The above dryer, Further comprising a motor providing driving force for rotating the drum; The above frequency control unit; A dryer that controls the motor to perform an operation to eliminate the overlapping phenomenon while alternately transmitting an optimal frequency input signal for each of the drying materials classified into the different categories to the switching element based on the determination that the overlapping phenomenon has occurred.

5. In paragraph 4, The above frequency control unit; A dryer that controls the motor to rotate the drum semi-periodically and stop the rotation of the drum to eliminate the overlapping phenomenon of the plurality of drying objects.

6. In paragraph 2, The above frequency control unit, A dryer that determines that a plurality of objects to be dried are accommodated in the drum based on the detection of a plurality of resonance points.

7. In paragraph 6, The above frequency control unit, A dryer that detects the phase difference between the detected voltage and the detected current based on the determination that the plurality of objects to be dried are accommodated in the drum, and determines the load characteristics of each of the plurality of objects to be dried in the drum based on the phase difference.

8. In paragraph 7, The above frequency control is A frequency control unit memory containing information about preset category-specific load characteristics; The above frequency control unit; A dryer that compares the load characteristics of each of the plurality of drying materials in the drum with the category-specific load characteristics stored in the frequency control unit memory and classifies the plurality of drying materials according to the preset categories.

9. In paragraph 8, The above frequency control unit; A dryer that detects an optimal frequency for each of the above-mentioned dry goods classified into different categories based on the above-mentioned plurality of dry goods being classified into different categories.

10. In paragraph 9, A dryer in which the optimal frequency for each of the above-mentioned objects classified into the different categories is the resonance frequency at the resonance point for each of the above-mentioned objects.

11. In paragraph 9, The above frequency control unit; A dryer that generates a pulse width modulation (PWM) signal for the optimal frequency for each of the above-detected objects classified into the different categories.

12. In paragraph 11, The above input signal variable part; A dryer further comprising an oscillator that generates an optimal frequency input signal for each of the drying materials classified into the different categories by taking as input a DC voltage value corresponding to the pulse width modulation from the frequency control unit.

13. A method for controlling a dryer, comprising: an electrode unit including a plurality of electrodes spaced apart along the outer surface of a drum; an RF power supply unit including a switching element that receives an input signal and amplifies the input signal to generate RF power applied to the electrode unit; an impedance matching circuit that performs impedance matching between the RF power supply unit and the electrode unit; and an input signal variable unit that varies the frequency of an input signal input to the switching element. Detecting the output voltage and output current of the output terminal of the above impedance matching circuit, Based on the output voltage and output current, it is determined whether a plurality of objects to be dried in the drum are received, Based on the determination that the plurality of dry items are accommodated in the drum, the plurality of dry items are classified according to preset categories, Based on the classification of the above multiple dry objects into different categories, an optimal frequency input signal is generated for each of the dry objects classified into the different categories in a time-division manner, A control method for a dryer, comprising transmitting the optimal frequency input signal to the switching element.

14. In paragraph 13, Determining whether the plurality of dry objects are accommodated in the drum is as follows: Detecting a resonance point and a resonance frequency at the resonance point based on the output voltage and the output current, A control method of a dryer, including determining that a plurality of the above-described objects are accommodated in the drum based on the detection of a plurality of the above-described resonance points.

15. In paragraph 14, The above method of controlling the dryer is as follows: A control method for a dryer further comprising determining that an overlapping phenomenon of the plurality of objects to be dried has occurred based on the detection of a resonance point at a frequency other than the resonance frequency of each of the plurality of objects to be dried, without detecting a resonance point for each of the plurality of objects to be dried.

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