Dryer and controlling method thereof

Abstract

A dryer (1) according to one embodiment may comprise: an AC power source (100) for supplying input voltage; a rectifier (200) for rectifying the supplied input voltage; a power amplifier (300) for providing output voltage by amplifying the rectified input voltage; a plurality of electrodes (500) to which the output voltage is applied; a matching circuit (400) which is connected between the power amplifier (300) and the plurality of electrodes (500) and which corrects the waveform of the output voltage provided from the power amplifier (300); and at least one processor (601) which detects a power value corresponding to the rectified input voltage and which acquires the magnitude of the output voltage provided from the power amplifier (300), wherein the at least one processor (601) can detect the power value corresponding to the rectified input voltage on the basis that the magnitude of the output voltage provided from the power amplifier (300) is less than or equal to a predetermined reference voltage (Vr).

Description

Dryer and method of controlling the same

[0001] The disclosed invention relates to a dryer and a method for controlling the same.

[0002] Conventional dryers apply heat to the material, drying it at high temperatures. However, high-temperature drying can cause damage and shrinkage. This has led to the need for a method that can dry at low temperatures without causing damage.

[0003] Drying can be achieved at low temperatures by utilizing the dielectric heating phenomenon. Dielectric heating occurs when insulating material is placed in a high-frequency electric field, generating heat through molecular friction within the material itself. Therefore, when a voltage is applied to a drying object placed between electrodes, the object can be dried by this dielectric heating phenomenon.

[0004] The disclosed invention provides a dryer capable of drying a material using a genetic heating method and a method for controlling the dryer.

[0005] According to one embodiment, a dryer (1) may include an AC power source (100) that supplies an input voltage; a rectifier (200) that rectifies the supplied input voltage; a power amplifier (300) that amplifies the rectified input voltage and provides an output voltage; a plurality of electrodes (500) to which the output voltage is applied; a matching circuit (400) that is connected between the power amplifier (300) and the plurality of electrodes (500) and corrects a waveform of the output voltage provided from the power amplifier (300); and at least one processor (601) that detects a power value corresponding to the rectified input voltage and obtains a magnitude of the output voltage provided from the power amplifier (300), wherein the at least one processor (601) may detect a power value corresponding to the rectified input voltage based on the magnitude of the output voltage provided from the power amplifier (300) being equal to or less than a predetermined reference voltage (Vr).

[0006] A method for controlling a dryer (1) according to one embodiment may include: supplying an input voltage through an AC power source (100); rectifying the supplied input voltage through a rectifier (200); amplifying the rectified input voltage through a power amplifier (300) to provide an output voltage; detecting a power value corresponding to the rectified input voltage based on whether the magnitude of the output voltage is lower than or equal to a predetermined reference voltage (Vr); controlling a matching circuit (400) to correct a waveform of the output voltage based on the detected power value; and controlling the power amplifier (300) to apply the output voltage to a plurality of electrodes (500) based on whether the magnitude of the output voltage is higher than the predetermined reference voltage (Vr).

[0007] According to the disclosed invention, there is an effect that the circuit of a dielectric heating type dryer (1) driven by high output and high voltage can be driven while effectively allowing circuit elements such as sensors to operate normally.

[0008] In addition, by optimizing the section for supplying power and the section for detecting the power value according to the size of the output voltage, it is possible to solve the noise problem when driven at high frequency and high output while simultaneously supplying power efficiently.

[0009] The technical tasks and effects to be achieved in this document are not limited to those described above, and other technical tasks and effects other than those mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0010] Figure 1 illustrates a circuit structure of a dryer according to one embodiment of the present invention.

[0011] Figure 2 is a flowchart showing a method for controlling a dryer according to one embodiment of the present invention.

[0012] FIG. 3 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0013] FIG. 4 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0014] Figure 5 is a graph showing the relationship between the supplied power and the lowest voltage at which the power supply operation is performed.

[0015] Figure 6 is a flowchart showing a control method of a dryer according to one embodiment of the present invention.

[0016] FIG. 7 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0017] FIG. 8 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0018] Figure 9 is a flowchart showing a method for controlling a dryer according to one embodiment of the present invention.

[0019] FIG. 10 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0020] Figure 11 is a flowchart showing a method for controlling a dryer according to one embodiment of the present invention.

[0021] FIG. 12 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0022] Figure 13 is a flowchart showing a method for controlling a dryer according to one embodiment of the present invention.

[0023] Figure 14 is a flowchart showing a control method of a dryer according to one embodiment of the present invention.

[0024] Figure 15 is a flowchart showing a method for controlling a dryer according to one embodiment of the present invention.

[0025] FIG. 16 is a graph showing a control method according to an output voltage provided from a power amplifier of a dryer according to one embodiment of the present invention.

[0026] Fig. 17 illustrates a three-phase circuit structure of a dryer according to one embodiment of the present invention.

[0027] FIG. 18 is a graph showing a control method according to three-phase output voltages provided from multiple power amplifiers of a dryer according to one embodiment of the present invention.

[0028] It should be understood that the various embodiments of the present disclosure and the terminology used therein are not intended to limit the technical features described in the present disclosure to specific embodiments, but rather to encompass various modifications, equivalents, or alternatives of the embodiments.

[0029] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0030] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0031] In this disclosure, 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 the corresponding phrase, or all possible combinations thereof.

[0032] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0033] 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).

[0034] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0035] Terms such as "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0036] 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.

[0037] 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.

[0038] Hereinafter, a dryer (1) and a control method according to various embodiments will be specifically described with reference to the attached drawings. In the description with reference to the attached drawings, identical or corresponding components are assigned similar drawing numbers, and redundant descriptions thereof may be omitted.

[0039] The dryer (1) according to the present invention is a drying method that uses a dielectric heating phenomenon, rather than a conventional clothes dryer that applies heat to the surface of a drying object by using a heating source such as a heating wire.

[0040] Dielectric heating refers to the heating process caused by dielectric loss in an insulating material in an electric field generated by a high-frequency source. Specifically, when a dielectric is placed between electrodes and a high-frequency voltage is applied to both electrodes, the dipoles constituting the dielectric alternately oscillate in the alternating electric field, generating vibrations corresponding to the applied frequency. This vibration generates frictional heat in the dipoles, similar to water, heating the dielectric.

[0041] In other words, compared to methods that dry by applying heat to the surface, dielectric heating, which involves internal heating, can evenly heat the moisture contained in the drying material in a short period of time. Therefore, utilizing dielectric heating can overcome the shortcomings of methods that apply heat to the surface of the drying material, such as conventional clothes dryers.

[0042] For example, the dryer (1) using a dielectric heating method according to the present invention can prevent plastic deformation that may occur when heat is applied. Therefore, the clothes dryer using a dielectric heating method can prevent shrinkage of clothes due to plastic deformation of the fibers. Accordingly, the types of clothes that can be placed in the dryer (1) are not limited.

[0043] In addition, since the dryer (1) of the genetic heating method according to the present invention is not surface heated, it is heated evenly, and thus, unlike a conventional clothes dryer, it may not be necessary to have a motor that rotates a drying container such as a drum to apply heat evenly.

[0044] In addition, products to which the dryer (1) using the genetic heating method according to the present invention can be applied are not limited to clothes dryers, clothes managers, clothes treatment devices, etc., as exemplified above. For example, it can be applied to food dryers, food waste treatment devices, microwave ovens, etc., which include a function for drying food.

[0045] In addition, the dryer (1) using the genetic heating method according to the present invention can be applied not only to household use but also to various medical and industrial purposes. For example, it can be applied to thermal therapy devices, deep-thermal heating devices, wood dryers, etc.

[0046] A dryer (1) using a dielectric heating method may include various circuits. Basically, the dryer (1) may include a PFC (Power Factor Correction) circuit for correcting the power factor by receiving an alternating current (AC) voltage of 220 V. For example, the PFC circuit may receive an alternating current (AC) voltage of 220 V and output a direct current (DC) voltage of 400 V.

[0047] In addition, the dryer (1) may include a DC / DC converter that steps down the DC voltage output from the PFC to a DC voltage of a desired magnitude. In addition, the dryer may include a power amplifier (300) that generates high-frequency, high-output power based on the DC voltage output from the DC / DC converter, a matching circuit for correcting a waveform that changes during operation, and an electrode (500) to which a voltage is applied.

[0048] The dryer (1) according to the present invention is characterized by supplying high-frequency and high-power power. Conventional converters used in home appliances switch at low frequencies of several tens of kilohertz and can be driven at high power. Furthermore, typical power amplifiers (300) used in communication equipment switch at high frequencies of several tens to several hundred megahertz and can be driven at low power.

[0049] Accordingly, although it is generally driven with low frequency and high output or high frequency and low output, in the case of a dryer (1) of a dielectric heating method such as the dryer (1) according to the present invention, a circuit capable of driving with high frequency and high output of several tens of MHz may be required.

[0050] For example, a circuit capable of driving at high frequencies of 13.56 MHz or higher and high output power of 1 kW or higher may be required. Accordingly, a Class E power amplifier (300) suitable for high output power may be used.

[0051]

[0052] Conventional circuits incorporate a DC / DC converter, allowing DC operation, allowing for continuous application of the same voltage. When operating at low power, continuous application of the same voltage, as described above, does not pose a significant problem. However, when operating at high output due to a large number of building materials, problems can arise.

[0053] To ensure optimal power supply, the power value of the circuit during operation must be detected, and impedance compensation must be performed through a matching circuit (400) based on the detected power value. However, when driven at high frequency and high output, problems may occur in sensor operation due to switching noise generated in the circuit.

[0054] In other words, circuit components developed to date have been optimized for low-frequency and high-power operation, or high-frequency and low-power operation. Consequently, robustness against noise at high frequencies and high power levels (MHz and kilowatts) has not been specified, leading to operational issues for conventional components.

[0055] Accordingly, the dryer (1) of the genetic heating method according to the present invention can include a circuit structure that can reduce the influence of switching noise even when driving a high-frequency and high-output circuit, while allowing circuit elements such as sensors to operate normally.

[0056] Below, the dryer (1) and its control method according to the present invention will be described in detail.

[0057] Figure 1 shows the circuit structure of a dryer (1) according to one embodiment.

[0058] Referring to FIG. 1, a dryer (1) according to the present invention may include an AC power source (100), an EMI filter (150) (Electro-Magnetic Interference Filter), a rectifier (200), a power amplifier (300), a plurality of electrodes (500), a matching circuit (400), and a control unit (600) that controls each of the aforementioned components.

[0059] The AC power source (100) can supply an input voltage that is an alternating current. The input voltage supplied from the AC power source (100) can be 220 V. The supplied input voltage can be transmitted to an EMI filter (150). Both ends of the AC power source (100) can be connected to nodes a and b, respectively.

[0060] The EMI filter (150) can remove noise included in the supplied input voltage. The EMI filter (150) can include a first capacitor (C1), a transformer (T), a second capacitor (C2), node a, node b, node c, and node d.

[0061] A first capacitor (C1) can be connected in parallel with an AC power source (100) between nodes a and b.

[0062] The transformer may include a first winding (L1) and a second winding (L2). The first winding (L1) and the second winding (L2) may be wound in the same direction. The first winding (L1) may be connected between node a and node c. The second winding (L2) may be connected between node b and node d. That is, the transformer (T) may be connected in parallel between the first capacitor (C1) and the second capacitor (C2).

[0063] A second capacitor (C2) can be connected in parallel with the transformer (T) between node c and node d.

[0064] A rectifier (200) is a type of circuit element or device for converting alternating current into direct current. The rectifier (200) can be classified into a half-wave rectifier (200) and a full-wave rectifier (200). The half-wave rectifier (200) can output only the positive section of a signal, and the full-wave rectifier (200) can output the negative section of a signal as a positive section. Therefore, when using a full-wave rectifier (200), the frequency can be doubled compared to when using a half-wave rectifier (200), and the average output voltage can be doubled, so the power utilization rate can be improved.

[0065] For this reason, as shown in Fig. 1, the rectifier (200) in the circuit of the dryer (1) according to the present invention may include a full-wave rectifier.

[0066] A full-wave rectifier may include two or more diodes. For example, a full-wave rectifier may include four diodes. Specifically, a full-wave rectifier may be configured by connecting two half-wave rectifiers, each of which has two diodes connected in series, in parallel.

[0067] The input voltage that has passed through the EMI filter (150) and the full-wave rectifier may have a pulsating form. For example, if the input voltage supplied from the AC power source (100) has a waveform with a frequency of 60 Hz, the input voltage that has been rectified through the EMI filter (150) and the full-wave rectifier may have a pulsating form with a frequency of 120 Hz.

[0068] Meanwhile, the dryer (1) according to the present invention may further include a third capacitor (C3), a node e connected to one end of the rectifier (200), and a node f connected to the other end of the rectifier (200). The third capacitor (C3) may be connected in parallel with the rectifier (200) between the node e and the node f.

[0069] The power amplifier (300) may be arranged to be connected to node e. The power amplifier (300) may receive a rectified input voltage from the rectifier (200) via node e.

[0070] The power amplifier (300) can amplify a rectified input voltage and provide an output voltage. Accordingly, power can be supplied through the power amplifier (300) in a size capable of driving a load required by the application.

[0071] A plurality of electrodes (500) may be provided. An output voltage provided from a power amplifier (300) may be applied to the plurality of electrodes (500). As the output voltage is applied to the plurality of electrodes (500), the object may be dried using a dielectric heating method.

[0072] When driven in the above manner, impedance may change over time due to various reasons such as heat generation, aging, and transmission lines. Aging can refer to a change in the characteristics of a component during use. If the impedance changes and begins to distort, there is a problem in that optimal power cannot be supplied. Therefore, it is necessary to periodically detect the power value (Power Level Sensing) and perform impedance matching based on the detected value to ensure optimal power supply. The above effect can be achieved by the matching circuit (400).

[0073] A matching circuit (400) may be arranged to be connected between a power amplifier (300) and a plurality of electrodes (500). In addition, the matching circuit (400) may correct the waveform of an output voltage provided from the power amplifier (300).

[0074] The control unit (600) may be electrically connected to the AC power source (100), the power amplifier (300), and the matching circuit (400), and may control each connected component. The control unit (600) may be connected to a first node (N1) provided between the rectifier (200) and the power amplifier (300).

[0075] In addition, the control unit (600) may include at least one processor (601) and at least one memory (602). The control unit (600) may include hardware such as a CPU or a memory (602), and software such as a control program. For example, the control unit (600) may include at least one memory (602) that stores data in the form of an algorithm and a program for controlling the operation of components within the dryer (1), and at least one processor (601) that performs the above-described operation using the data stored in the at least one memory (602). The memory (602) and the processor (601) may each be implemented as separate chips. The processor (601) may include one or more processor (601) chips or one or more processing cores. The memory (602) may include one or more memory (602) chips or one or more memory (602) blocks. Additionally, the memory (602) and the processor (601) may be implemented as a single chip.

[0076] The specific control operation of the control unit (600) will be described later.

[0077] Fig. 2 is a flowchart showing a control method of a dryer (1) according to one embodiment.

[0078] Referring to FIG. 2, the control unit (600) can control the AC power source (100) to supply an input voltage. The input voltage supplied from the AC power source (100) can be transmitted to the rectifier (200). The rectifier (200) can rectify the input voltage. (210)

[0079] The rectified input voltage can be transmitted to a power amplifier (300). The power amplifier (300) can amplify the rectified input voltage and provide an output voltage. (220)

[0080] The control unit (600) can obtain the size of the output voltage provided from the power amplifier (300). (230)

[0081] The control unit (600) can perform a series of control operations by comparing the magnitude of the acquired output voltage with the magnitude of a predetermined reference voltage (Vr). To this end, the control unit (600) can determine the magnitude of the reference voltage in advance. The control unit (600) can determine whether the magnitude of the output voltage is equal to or less than the predetermined reference voltage (Vr). (240)

[0082] The control unit (600) can detect a power value corresponding to the rectified input voltage based on whether the size of the output voltage is lower than or equal to a predetermined reference voltage (Vr). (251) This is because when the size of the output voltage is large, the power value may not be accurately detected due to excessive switching noise, so the power value is detected only when the size of the output voltage is lower than or equal to a certain reference voltage.

[0083] The control unit (600) can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on whether the magnitude of the output voltage exceeds a predetermined reference voltage (Vr). (252) This is to supply power only when the magnitude of the output voltage is greater than a certain reference voltage, as it is more efficient to supply power when the magnitude of the output voltage is greater.

[0084] Fig. 3 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment. The x-axis of Fig. 3 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In Fig. 3, ① means a time period during which an operation of supplying power is performed, and ② means a time period during which a power value is detected.

[0085] Referring to FIG. 3, it can be confirmed that the output voltage in the time periods t0 to t1, t2 to t3, and t4 to t5, which are indicated by dark shading, is greater than the reference voltage (Vr). Therefore, in the time periods t0 to t1, t2 to t3, and t4 to t5, the control unit (600) can control the power amplifier (300) so that the output voltage is applied to the plurality of electrodes (500).

[0086] Likewise, it can be confirmed that the output voltage is lower than the reference voltage (Vr) in the time periods t1 to t2, t3 to t4, and t5 to t6 indicated by light shading in FIG. 3. Therefore, in the time periods t1 to t2, t3 to t4, and t5 to t6, the control unit (600) can detect a power value corresponding to the rectified input voltage.

[0087] As above, by dividing the operation into a section for supplying power and a section for detecting the power value according to the size of the output voltage, it is possible to solve the noise problem and efficiently supply power when driven at high frequency and high output.

[0088] Fig. 4 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment. The x-axis of Fig. 4 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In Fig. 4, ① means a time period during which an operation of supplying power is performed, ② means a time period during which a power value is detected, and ③ means a time period during which impedance matching or correction of the output voltage is performed.

[0089] Referring to FIGS. 2 and 4, the control unit (600) can control the matching circuit (400) to correct the waveform of the output voltage based on the detected power value. (260)

[0090] Referring to Fig. 4, it can be confirmed that the output voltages of the time periods t0 to t1, t2 to t3, and t4 to t5, which are indicated by dark shading, are greater than the reference voltage (Vr). Therefore, in the time periods t0 to t1, t2 to t3, and t4 to t5, the control unit (600) can control the power amplifier (300) so that the output voltage is applied to the plurality of electrodes (500).

[0091] Likewise, it can be confirmed that the output voltage is lower than the reference voltage (Vr) in the time sections t1 to t2, t3 to t4, and t5 to t6 indicated by light shading in FIG. 4. Therefore, in the time sections t1 to t2, t3 to t4, and t5 to t6, the control unit (600) may detect a power value corresponding to the rectified input voltage, and may correct the waveform of the output voltage based on the detected power value. For example, as illustrated in FIG. 4, the power value may be detected in the time sections t1 to t2, t5 to t6, and the waveform of the output voltage may be corrected based on the detected power value in the time sections t3 to t4.

[0092]

[0093] Since the Class E power amplifier (300) is driven by high frequency and high output, the main switch included in the Class E power amplifier (300) must satisfy zero voltage switching operation. If zero voltage switching is not performed, the device may be damaged due to energy loss caused by hard switching.

[0094] Common switching elements, such as MOSFETs and GANs, can have parasitic capacitances (Coss) that vary depending on the source-drain voltage. The resonant frequency changes based on the parasitic capacitance. At high voltages, the parasitic capacitance decreases, and the resonant frequency of the Class E power amplifier (300) can be high. Accordingly, the resonant period is short, so that zero-voltage switching can be well satisfied.

[0095] However, at low voltages, parasitic capacitance increases, and the resonant frequency of the Class E power amplifier (300) may be low. Consequently, the resonant period may be long, making it difficult to satisfy zero-voltage switching. Therefore, it is necessary to minimize the power supply operation during low-voltage periods.

[0096] Figure 5 is a graph showing the relationship between the supplied power and the lowest voltage at which the power supply operation is performed.

[0097] The x-axis of Figure 5 can represent the power supplied, and the y-axis can represent the size of the lowest voltage that performs the power supply operation.

[0098] The dryer (1) according to the present invention may vary the amount of power to be supplied as the load, such as the amount of dry matter and the degree of dryness, changes. Here, the meaning of a change in load may include changes in real time during operation and variations in the amount of dry matter supplied prior to operation, depending on the case.

[0099] The control unit (600) can control the operation of applying the output voltage to be performed differently depending on the magnitude of the power supply corresponding to the load. In other words, the lowest voltage that serves as a reference for performing the operation of supplying power can be determined based on the magnitude of the power supply corresponding to the load.

[0100] Specifically, when supplying high power, the entire power supply period can be utilized based on a voltage greater than a predetermined reference voltage (Vr). This is because, in some cases, supplying high power may require utilizing a low-voltage range.

[0101] Additionally, when supplying low power, some of the power supply time can be utilized. This is because the desired power can be supplied without necessarily utilizing the low-voltage range. Therefore, when supplying low power, only the high-output voltage time can be utilized.

[0102] Here, the control unit (600) can preset the size of the supplied power that distinguishes between high power and low power.

[0103] Referring to FIG. 5, the control unit (600) can determine the lowest voltage for performing an operation of supplying power based on the magnitude of the supplied power being greater than a preset first power value (P1) as the first voltage value (V1).

[0104] Additionally, the control unit (600) may determine the lowest voltage for performing an operation of supplying power as the second voltage value (V2) based on the fact that the size of the supplied power is smaller than the preset second power value (P2). Here, the preset second power value (P2) may be smaller than the preset first power value (P1).

[0105] In addition, the control unit (600) may determine the minimum voltage for performing the power supply operation as being greater than or equal to the first voltage value (V1) and less than or equal to the second voltage value (V2) based on the fact that the size of the supplied power is greater than or equal to the preset second power value (P2) and less than or equal to the preset first power value (P1). Here, the control unit (600) may determine that the minimum voltage for performing the power supply operation becomes smaller as the size of the supplied power increases. Here, the second voltage value (V2) may be greater than the first voltage value (V1).

[0106] Figure 6 is a flowchart showing a control method of a dryer (1) according to one embodiment of the present invention.

[0107] Referring to FIGS. 5 and 6, the control unit (600) can control the AC power source (100) to supply an input voltage. The input voltage supplied from the AC power source (100) can be transmitted to the rectifier (200). The rectifier (200) can rectify the input voltage. (610)

[0108] The rectified input voltage can be transmitted to the power amplifier (300). The control unit (600) can control the power amplifier (300) to amplify the rectified input voltage and provide an output voltage. (620)

[0109] The control unit (600) can determine the minimum voltage at which power is supplied based on the magnitude of the power supply corresponding to the load. For example, the control unit (600) can determine whether the magnitude of the power supply is greater than a preset first power value (P1). (630)

[0110] The control unit (600) can obtain the size of the output voltage provided from the power amplifier (300).

[0111] The control unit (600) can perform a series of control operations by comparing the magnitude of the acquired output voltage with the magnitude of the first voltage value (V1) based on the magnitude of the supplied power being greater than the preset first power value (P1). Specifically, the control unit (600) can determine whether the magnitude of the output voltage is less than or equal to the first voltage value (V1). (640)

[0112] The control unit (600) can detect a power value corresponding to the rectified input voltage based on the magnitude of the output voltage being less than or equal to the first voltage value (V1). Here, the control unit (600) can first identify whether a power value already detected exists. (651)

[0113] If the control unit (600) identifies that a power value has already been detected, it can correct the waveform of the output voltage based on the detected power value. (661)

[0114] If the control unit (600) determines that the power value already detected does not exist, the control unit (600) can detect a power value corresponding to the rectified input voltage. (662) Thereafter, the control unit (600) can correct the waveform of the output voltage based on the detected power value.

[0115] Meanwhile, the control unit (600) can control the power amplifier (300) to apply an output voltage to a plurality of electrodes (500) based on the magnitude of the output voltage being greater than the first voltage value (V1). (652)

[0116] Fig. 7 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment of the present invention. The x-axis of Fig. 7 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In Fig. 7, ① means a time period during which an operation of supplying power is performed, ② means a time period during which a power value is detected, and ③ means a time period during which impedance matching or correction of the output voltage is performed.

[0117] Referring to FIG. 5 or FIG. 7, if the size of the supplied power is greater than the preset first power value (P1), the lowest voltage for performing the power supply operation can be determined as the first voltage value (V1), so that the entire power supply time period can be used.

[0118] It can be confirmed that the output voltages of the time periods t0 to t1, t2 to t3, and t4 to t5, which are indicated by dark shading in Fig. 7, are greater than the first voltage value (V1). Therefore, in the time periods t0 to t1, t2 to t3, and t4 to t5, the control unit (600) can control the power amplifier (300) so that the output voltage is applied to the plurality of electrodes (500).

[0119] Likewise, it can be confirmed that the time periods t1 to t2, t3 to t4, and t5 to t6, which are indicated by light shading in FIG. 7, have output voltages that are lower than the first voltage value (V1). Therefore, in the time periods t1 to t2, t3 to t4, and t5 to t6, the control unit (600) may detect a power value corresponding to the rectified input voltage, and may correct the waveform of the output voltage based on the detected power value. For example, as illustrated in FIG. 7, the power value may be detected in the time periods t1 to t2, t5 to t6, and the waveform of the output voltage may be corrected based on the detected power value in the time periods t3 to t4.

[0120] FIG. 8 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment of the present invention. The x-axis of FIG. 8 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In FIG. 8, ① refers to a time period during which an operation of supplying power is performed, ② refers to a time period during which a power value is detected, and ③ refers to a time period during which impedance matching or correction of the output voltage is performed.

[0121] As shown in Fig. 7, when using all areas of the power supply time period, it is necessary to reduce the operation of low voltages because it becomes difficult to satisfy zero voltage switching as the voltage decreases.

[0122] Accordingly, when the size of the supplied power is greater than the preset first power value (P1), the control unit (600) can control the power amplifier (300) to use only a portion of the time period in which power is supplied during any time period.

[0123] Referring to FIG. 8, unlike that illustrated in FIG. 7, the control unit (600) may determine the lowest voltage for performing an operation of supplying power as the second voltage value (V2) so that power is supplied only during the time period t7 to t8, which is a part of the time period t2 to t3, rather than supplying power during the entire time period t2 to t3.

[0124] Accordingly, the control unit (600) controls the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the first voltage value (V1) when the size of the supplied power is greater than the preset first power value (P1), but can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the second voltage value (V2) in any time period.

[0125] In other words, when the size of the supplied power is greater than the first power value (P1) that is set in advance, the control unit (600) sets the minimum voltage, which is the reference for supplying power by applying the output voltage, as the first voltage value (V1), because the power that must be supplied is large. However, in order to satisfy zero voltage switching, the minimum voltage, which is the reference for supplying power, can be changed to the second voltage value (V2) during any time period in which a relatively low output voltage is applied. For example, as illustrated in FIG. 8, the control unit (600) can control the power amplifier (300) to alternately perform the first voltage value (V1) as the minimum voltage, which is the reference for supplying power by applying the output voltage, and the second voltage value (V2) as the minimum voltage, which is the reference for supplying power by applying the output voltage.

[0126] Figure 9 is a flowchart showing a control method of a dryer (1) according to one embodiment of the present invention.

[0127] Referring to FIG. 9, the control unit (600) can control the AC power source (100) to supply an input voltage. The input voltage supplied from the AC power source (100) can be transmitted to the rectifier (200). The rectifier (200) can rectify the input voltage. (910)

[0128] The rectified input voltage can be transmitted to the power amplifier (300). The control unit (600) can control the power amplifier (300) to amplify the rectified input voltage and provide an output voltage. (920)

[0129] The control unit (600) can determine the minimum voltage at which power is supplied based on the magnitude of the power supply corresponding to the load. For example, the control unit (600) can determine whether the magnitude of the power supply is less than a preset second power value (P2). (930)

[0130] The control unit (600) can obtain the size of the output voltage provided from the power amplifier (300).

[0131] The control unit (600) can perform a series of control operations by comparing the magnitude of the acquired output voltage with the magnitude of the second voltage value (V2) based on the magnitude of the supplied power being smaller than the preset second power value (P2). Specifically, the control unit (600) can determine whether the magnitude of the output voltage is less than or equal to the second voltage value (V2). (940)

[0132] The control unit (600) can detect a power value corresponding to the rectified input voltage based on the magnitude of the output voltage being less than or equal to the second voltage value (V2). Here, the control unit (600) can first identify whether a power value already detected exists. (951)

[0133] If the control unit (600) identifies that a power value has already been detected, it can correct the waveform of the output voltage based on the detected power value. (961)

[0134] If the control unit (600) determines that the power value already detected does not exist, the control unit (600) can detect a power value corresponding to the rectified input voltage. (962) Thereafter, the control unit (600) can correct the waveform of the output voltage based on the detected power value.

[0135] Meanwhile, the control unit (600) can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the magnitude of the output voltage is greater than the second voltage value (V2). (952)

[0136] Fig. 10 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment of the present invention. The x-axis of Fig. 10 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In Fig. 10, ① refers to a time period during which an operation of supplying power is performed, ② refers to a time period during which a power value is detected, and ③ refers to a time period during which impedance matching or correction of the output voltage is performed.

[0137] As described above, in the case of low power with a small supply power, the desired power can be supplied without necessarily using the area where a low output voltage is applied. Accordingly, the control unit (600) can control the power amplifier (300) to not supply power in an area with a low output voltage where it is difficult to satisfy zero voltage switching, and to supply power only in an area where the output voltage is higher than a certain level.

[0138] Referring to Fig. 10, it can be confirmed that the output voltage in the time periods t9 to t10, t11 to t12, and t13 to t14, which are indicated by dark shading, is greater than the second voltage value (V2). Accordingly, the control unit (600) can control the power amplifier (300) so that the output voltage is applied to the plurality of electrodes (500) in the time periods t9 to t10, t11 to t12, and t13 to t14.

[0139] Likewise, it can be confirmed that the output voltage is smaller than the first voltage value (V1) in the time sections t1 to t2, t3 to t4, and t5 to t6 indicated by light shading in FIG. 10. Therefore, in the time sections t1 to t2, t3 to t4, and t5 to t6, the control unit (600) may detect a power value corresponding to the rectified input voltage, and may correct the waveform of the output voltage based on the detected power value. For example, as illustrated in FIG. 10, in the time sections t1 to t2, t5 to t6, a power value may be detected, and in the time sections t3 to t4, the waveform of the output voltage may be corrected based on the detected power value.

[0140] Fig. 11 is a flowchart showing a control method of a dryer (1) according to one embodiment of the present invention.

[0141] Referring to FIG. 11, the control unit (600) can control the AC power source (100) to supply an input voltage. The input voltage supplied from the AC power source (100) can be transmitted to the rectifier (200). The rectifier (200) can rectify the input voltage. (1110)

[0142] The rectified input voltage can be transmitted to the power amplifier (300). The control unit (600) can control the power amplifier (300) to amplify the rectified input voltage and provide an output voltage. (1120)

[0143] The control unit (600) can determine the minimum voltage at which power is supplied based on the magnitude of the power supply corresponding to the load. For example, the control unit (600) can determine whether the magnitude of the power supply is greater than or equal to a preset second power value (P2) and less than or equal to a preset first power value (P1). (1130)

[0144] The control unit (600) can obtain the size of the output voltage provided from the power amplifier (300).

[0145] Here, a third voltage value can be determined based on the size of the supplied power. (1140) Here, the third voltage value can be included in a range greater than or equal to the first voltage value (V1) and less than or equal to the second voltage value (V2).

[0146] The control unit (600) can perform a series of control operations by comparing the magnitude of the acquired output voltage with the magnitude of the third voltage value based on the fact that the magnitude of the supplied power is greater than or equal to a preset second power value (P2) and less than or equal to a preset first power value (P1). Specifically, the control unit (600) can determine whether the magnitude of the output voltage is less than or equal to the third voltage value (1150).

[0147] The control unit (600) can detect a power value corresponding to the rectified input voltage based on the fact that the magnitude of the output voltage is less than or equal to the third voltage value. Here, the control unit (600) can first identify whether a power value already detected exists. (1161)

[0148] If the control unit (600) identifies that a power value has already been detected, it can correct the waveform of the output voltage based on the detected power value. (1171)

[0149] If the control unit (600) determines that the power value already detected does not exist, the control unit (600) can detect a power value corresponding to the rectified input voltage. (1172) Thereafter, the control unit (600) can correct the waveform of the output voltage based on the detected power value.

[0150] Meanwhile, the control unit (600) can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the magnitude of the output voltage being greater than the third voltage value. (1162)

[0151] Fig. 12 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment of the present invention. The x-axis of Fig. 12 may represent time (t), and the y-axis may represent an output voltage provided from the power amplifier (300). In Fig. 12, ① refers to a time period during which an operation of supplying power is performed, ② refers to a time period during which a power value is detected, and ③ refers to a time period during which impedance matching or correction of the output voltage is performed.

[0152] When the power supply is of an intermediate power, not a high power greater than a preset first power value (P1) or a low power less than a preset second power value (P2), the control unit (600) can flexibly determine the lowest voltage for performing the power supply operation between the first voltage value (V1) and the second voltage value (V2). By controlling in this manner, there is an effect of optimizing the power supply time period depending on the power supply size.

[0153] Referring to Fig. 12, it can be confirmed that the output voltage in the time sections t9 to t10, t11 to t12, and t13 to t14, which are indicated by dark shading, is greater than the third voltage value (V3). Accordingly, the control unit (600) can control the power amplifier (300) so that the output voltage is applied to the plurality of electrodes (500) in the time sections t9 to t10, t11 to t12, and t13 to t14. Looking at the size of the time sections indicated by dark shading in Fig. 12, it can be confirmed that it is smaller than the time sections indicated by dark shading in Fig. 7, and larger than the time sections indicated by dark shading in Fig. 10.

[0154] Likewise, it can be confirmed that the time periods t1 to t2, t3 to t4, and t5 to t6, which are indicated by light shading in FIG. 12, have output voltages that are smaller than the first voltage value (V1)(V1). Therefore, in the time periods t1 to t2, t3 to t4, and t5 to t6, the control unit (600) may detect a power value corresponding to the rectified input voltage, and may correct the waveform of the output voltage based on the detected power value. For example, as illustrated in FIG. 10, in the time periods t1 to t2, t5 to t6, a power value may be detected, and in the time periods t3 to t4, the waveform of the output voltage may be corrected based on the detected power value.

[0155]

[0156] So far, we have described a method for determining the time period for supplying power and the time period for performing power value detection or impedance matching according to the size of the output voltage, and a method for determining the optimal time period for supplying power according to the size of the supplied power.

[0157] Below, we describe a method for optimizing the operating time during which power supply, power value detection, and impedance matching are performed.

[0158] When applying an output voltage to a plurality of electrodes (500) according to a series of control methods described above, the size of the time period during which power is supplied needs to be set to match the size of the supplied power. This is because if the size of the time period during which power is supplied is too small compared to the size of the supplied power, power may not be supplied properly, resulting in a decrease in efficiency. On the other hand, if the size of the time period during which power is supplied is too large compared to the size of the supplied power, the operating time for power value detection or impedance matching may be insufficient, resulting in the function not being performed properly.

[0159] Fig. 13 is a flowchart showing a control method of a dryer (1) according to one embodiment.

[0160] Referring to FIG. 13, the control unit (600) can control the power amplifier (300) to apply an output voltage to a plurality of electrodes (500). (1310) Here, the control unit (600) can include controlling the power amplifier (300) according to a series of control methods described with reference to FIG. 1 to FIG. 12.

[0161] The control unit (600) can obtain the first operation time during which the operation of applying the output voltage is performed. (1320)

[0162] The control unit (600) can determine whether the acquired first operation time is sufficient. That is, the control unit (600) can determine whether power has been properly supplied in accordance with the magnitude of the supplied power. In addition, the control unit (600) can calculate the time required to apply an output voltage corresponding to the magnitude of the supplied power.

[0163] In other words, the control unit (600) can compare the acquired first operating time with the time required to apply an output voltage corresponding to the magnitude of the supplied power. Specifically, the control unit (600) can determine whether the acquired first operating time is shorter than the time required to apply an output voltage corresponding to the magnitude of the supplied power. (1330)

[0164] The control unit (600) can reduce the predetermined reference voltage (Vr) if the acquired first operation time is shorter than the time required to apply the output voltage corresponding to the size of the supplied power. (1341) When the predetermined reference voltage (Vr) is reduced, the first operation time increases, so that the size of the time period during which power supply is performed can be adjusted to suit the size of the supplied power. Here, the predetermined reference voltage (Vr) may mean a voltage that serves as a standard for dividing the time period during which power is supplied and the time period during which power value detection or impedance matching is performed.

[0165] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) is reduced based on the difference between the first operating time and the time required to apply the output voltage corresponding to the magnitude of the supplied power. The greater the difference between the first operating time and the time required to apply the output voltage corresponding to the magnitude of the supplied power, the greater the amount by which the predetermined reference voltage (Vr) is reduced.

[0166] The control unit (600) can determine whether the acquired first operation time is greater than the time required to apply an output voltage corresponding to the size of the supplied power. (1342) If the acquired first operation time is greater than the time required to apply an output voltage corresponding to the size of the supplied power, the control unit (600) can increase a predetermined reference voltage (Vr). (1350) If the predetermined reference voltage (Vr) is increased, the first operation time is decreased, so that the size of the time period during which power supply is performed can be adjusted to suit the size of the supplied power.

[0167] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) increases based on the difference between the first operating time and the time required to apply the output voltage corresponding to the magnitude of the supplied power. The greater the difference between the first operating time and the time required to apply the output voltage corresponding to the magnitude of the supplied power, the greater the amount by which the predetermined reference voltage (Vr) increases.

[0168] When detecting a power value corresponding to a rectified input voltage according to a series of control methods described above, the size of the time period during which the power value detection is performed needs to be appropriately set so that the power value detection can be sufficiently performed.

[0169] This is because, if the size of the time interval during which power value detection is performed is too small compared to the time required for power value detection, power value detection is not performed properly, making it difficult to perform impedance matching based on this, and if the size of the time interval during which power value detection is performed is too large compared to the time required for power value detection, the operating time for power supply may be insufficient, resulting in a decrease in power efficiency.

[0170] Fig. 14 is a flowchart showing a control method of a dryer (1) according to one embodiment.

[0171] Referring to FIG. 14, the control unit (600) can detect a power value corresponding to a rectified input voltage. (1410) Here, the control unit (600) can detect the power value according to a series of control methods described with reference to FIG. 1 to FIG. 12.

[0172] The control unit (600) can obtain the second operation time during which the operation of detecting the power value is performed. (1420)

[0173] The control unit (600) can determine whether the acquired second operation time is sufficient. In other words, the control unit (600) can determine whether the power value detection was performed properly. In addition, the control unit (600) can calculate the time required for the power value detection.

[0174] In other words, the control unit (600) can compare the acquired second operating time with the time required to detect the power value. Specifically, the control unit (600) can determine whether the acquired second operating time is shorter than the time required to detect the power value (1430).

[0175] The control unit (600) can increase the predetermined reference voltage (Vr) if the acquired second operation time is less than the time required for power value detection. (1441) When the predetermined reference voltage (Vr) increases, the second operation time increases, so that the size of the time period required for power value detection can be appropriately adjusted so that power value detection can be performed properly.

[0176] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) increases based on the difference between the second operating time and the time required to detect the power value. The greater the difference between the second operating time and the time required to detect the power value, the greater the amount by which the predetermined reference voltage (Vr) increases.

[0177] The control unit (600) can determine whether the acquired second operation time is greater than the time required for power value detection. (1442) If the acquired second operation time is greater than the time required for power value detection, the control unit (600) can reduce the predetermined reference voltage (Vr). (1450) If the predetermined reference voltage (Vr) is reduced, the second operation time is reduced, so that the power value detection can be appropriately adjusted so that the power value detection can be performed only for the time required for power value detection.

[0178] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) is reduced based on the difference between the second operating time and the time required to detect the power value. The greater the difference between the second operating time and the time required to detect the power value, the greater the amount by which the predetermined reference voltage (Vr) is reduced.

[0179] Fig. 15 is a flowchart showing a control method of a dryer (1) according to one embodiment.

[0180] When impedance matching for correcting the waveform of the output voltage is performed according to a series of control methods described above, the size of the time for which the waveform correction of the output voltage is performed needs to be appropriately set so that the waveform correction can be sufficiently performed.

[0181] This is because, if the size of the time for which waveform correction of the output voltage is performed is too small compared to the time required for waveform correction, impedance matching may not be properly performed, preventing optimal power supply and resulting in reduced efficiency. On the other hand, if the size of the time for which waveform correction is performed is too large compared to the time required for power value detection, the operating time for power supply may be insufficient, resulting in reduced power efficiency.

[0182] Referring to FIG. 15, the control unit (600) can control the matching circuit (400) to correct the waveform of the output voltage. (1510) Here, the control unit (600) can correct the waveform of the output voltage according to a series of control methods described with reference to FIG. 1 to FIG. 12.

[0183] The control unit (600) can obtain a third operation time during which an operation to correct the waveform of the output voltage is performed. (1520)

[0184] The control unit (600) can determine whether the acquired third operating time is sufficient. That is, the control unit (600) can determine whether impedance matching has been properly achieved. In addition, the control unit (600) can calculate the time required for waveform correction of the output voltage.

[0185] In other words, the control unit (600) can compare the acquired third operating time with the time required for waveform correction of the output voltage. Specifically, the control unit (600) can determine whether the acquired third operating time is shorter than the time required for waveform correction of the output voltage. (1530)

[0186] The control unit (600) can increase the predetermined reference voltage (Vr) if the acquired third operation time is less than the time required for waveform correction of the output voltage. (1541) When the predetermined reference voltage (Vr) increases, the third operation time increases, so that the size of the time required for waveform correction of the output voltage can be appropriately adjusted so that impedance matching can be properly achieved.

[0187] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) increases based on the difference between the third operating time and the time required for waveform correction of the output voltage. The greater the difference between the third operating time and the time required for waveform correction of the output voltage, the greater the amount by which the predetermined reference voltage (Vr) increases.

[0188] The control unit (600) can determine whether the acquired third operation time is greater than the time required for waveform correction of the output voltage. (1542) If the acquired third operation time is greater than the time required for waveform correction of the output voltage, the control unit (600) can reduce the predetermined reference voltage (Vr). (1550) If the predetermined reference voltage (Vr) is reduced, the third operation time is reduced, so that the impedance matching can be appropriately adjusted so that it is performed only for the time required for waveform correction of the output voltage.

[0189] The control unit (600) can determine the amount by which the predetermined reference voltage (Vr) is reduced based on the difference between the third operating time and the time required for waveform correction of the output voltage. The greater the difference between the third operating time and the time required for waveform correction of the output voltage, the greater the amount by which the predetermined reference voltage (Vr) is reduced.

[0190] FIG. 16 is a graph showing a control method according to an output voltage provided from a power amplifier (300) of a dryer (1) according to one embodiment of the present invention.

[0191] The x-axis of Fig. 16 may represent time (t), and the y-axis may represent the output voltage provided from the power amplifier (300). In Fig. 16, ① means a time period during which an operation of supplying power is performed, ② means a time period during which a power value is detected, and ③ means a time period during which impedance matching or correction of the output voltage is performed.

[0192] Fig. 16 illustrates timing control for increasing or decreasing a predetermined reference voltage (Vr) to optimize each operation time of power supply, power value detection, and impedance matching described based on Fig. 13 to Fig. 15.

[0193] Referring to FIG. 16, the control unit (600) can perform a series of control operations based on the size of the first reference voltage (Vr1) and the output voltage that are predetermined in the time period t0 to t4.

[0194] Specifically, the control unit (600) can apply an output voltage to a plurality of electrodes (500) to supply power based on the magnitude of the output voltage being greater than a first reference voltage (Vr1) that is predetermined. In addition, the control unit (600) can detect a power value or correct a waveform of the output voltage based on the magnitude of the output voltage being less than or equal to the first reference voltage (Vr1) that is predetermined.

[0195] For example, power supply may be performed in the time periods t0 to t1 and t2 to t3 of FIG. 16, power value detection may be performed in the time periods t1 to t2, and impedance matching may be performed in the time periods t3 to t4.

[0196] However, if the first operation time for applying the output voltage as described in Fig. 13 is not appropriate and the power supply timing is not optimized, if the second operation time for detecting the power value as described in Fig. 14 is not appropriate and the power detection timing is not optimized, or if the third operation time for correcting the waveform of the output voltage as described in Fig. 15 is not appropriate and the impedance matching timing is not optimized, the timing at which each operation is performed needs to be appropriately adjusted. This is hereinafter referred to as timing control.

[0197] Accordingly, the control unit (600) can appropriately adjust the first operation time, the second operation time, or the third operation time by increasing or decreasing the first reference voltage (Vr1) set in advance at the time point (tc) at which the timing control of FIG. 16 is performed.

[0198] When the first operation time is insufficient or the second operation time or the third operation time is excessive, the control unit (600) can reduce the predetermined first reference voltage (Vr1) to the predetermined second reference voltage (Vr2) as shown in FIG. 16.

[0199] Conversely, if the first operation time is excessive or the second operation time or the third operation time is insufficient, the control unit (600) may increase the predetermined first reference voltage (Vr1) to the predetermined second reference voltage (Vr2), unlike as shown in FIG. 16.

[0200]

[0201] The timing control described in accordance with FIG. 13 or FIG. 16 need not be performed in real time or every time. Accordingly, the control unit (600) can perform the aforementioned timing control at any time interval.

[0202] In addition, the control unit (600) can predetermine a cycle for performing timing control. The control unit (600) can increase or decrease a predetermined reference voltage (Vr) based on the predetermined timing control cycle.

[0203] Accordingly, there is an effect of optimizing the time for power supply, power value detection, and impedance matching.

[0204] Fig. 17 shows the circuit structure of a dryer (1) according to one embodiment.

[0205] The circuit of the dryer (1) according to the present invention may be driven in three phases. Here, the three phases may include U phase, V phase, and W phase. In the case of three-phase driving, three circuits for each phase may operate in parallel. The circuit of the dryer (1) according to the present invention may include a structure capable of controlling the three circuits in an integrated manner. In this case, there is an effect that can significantly increase efficiency and design convenience.

[0206] Referring to FIG. 17, a dryer (1) according to the present invention may include an AC power source (100), an EMI filter (150), a rectifier (200), a plurality of power amplifiers (300), a plurality of electrodes (500), a plurality of matching circuits (400), and a control unit (600) that controls each of the aforementioned components.

[0207] The AC power source (100) can supply an input voltage that is an alternating current. The input voltage supplied from the AC power source (100) can be 220 V and can be transmitted to the EMI filter (150). Both ends of the AC power source (100) can be connected to nodes a and b, respectively. The input voltage can include three phases: a U-phase input voltage, a V-phase input voltage, and a W-phase input voltage.

[0208] The EMI filter (150) can remove noise included in the supplied input voltage. The EMI filter (150) can include a first capacitor (C1), a transformer (T), a second capacitor (C2), node a, node b, node c, and node d.

[0209] A first capacitor (C1) can be connected in parallel with an AC power source (100) between nodes a and b.

[0210] The transformer (T) may include a first winding (L1) and a second winding (L2). The first winding (L1) and the second winding (L2) may be wound in the same direction. The first winding (L1) may be connected between node a and node c. The second winding (L2) may be connected between node b and node d. That is, the transformer (T) may be connected in parallel between the first capacitor (C1) and the second capacitor (C2).

[0211] A second capacitor (C2) can be connected in parallel with the transformer (T) between node c and node d.

[0212] A rectifier (200) is a type of circuit element or device for converting alternating current into direct current. The rectifier (200) can be classified into a half-wave rectifier and a full-wave rectifier. A half-wave rectifier can output only the positive section of a signal, and a full-wave rectifier can output the negative section of a signal as a positive section. Therefore, when using a full-wave rectifier, the frequency can be doubled compared to when using a half-wave rectifier, and the average output voltage can be doubled, so that the power utilization rate can be improved. For this reason, as illustrated in FIG. 1, the rectifier (200) in the circuit of the dryer (1) according to the present invention can include a full-wave rectifier.

[0213] The rectifier (200) may include two or more diodes. For example, the rectifier (200) may include four diodes. Specifically, the rectifier (200) may be configured in a form in which two half-wave rectifiers, each having two diodes connected in series, are connected in parallel.

[0214] The input voltage that has passed through the EMI filter (150) and the rectifier (200) may have a pulsating form. For example, if the input voltage supplied from AC voltage has a waveform with a frequency of 60 Hz, the input voltage that has been rectified through the EMI filter (150) and the rectifier (200) may have a pulsating form with a frequency of 120 Hz.

[0215] Meanwhile, the dryer (1) according to the present invention may further include a third capacitor (C3), a node e connected to one end of the rectifier (200), and a node f connected to the other end of the rectifier (200). The third capacitor (C3) may be connected in parallel with the rectifier (200) between the node e and the node f.

[0216] A plurality of power amplifiers (300) may be arranged to be connected in parallel with the rectifier (200) via node e. The plurality of power amplifiers (300) may receive a rectified input voltage from the rectifier (200).

[0217] A plurality of power amplifiers (300) may include a first power amplifier (301) that amplifies a U-phase input voltage to provide a U-phase output voltage, a second power amplifier (302) that amplifies the W-phase input voltage to provide a V-phase output voltage, and a third power amplifier (303) that amplifies the V-phase input voltage to provide a W-phase output voltage.

[0218] The plurality of electrodes (500) may include a first electrode (501) to which a U-phase output voltage is applied, a second electrode (502) to which a V-phase output voltage is applied, and a third electrode (503) to which a W-phase output voltage is applied.

[0219] The plurality of matching circuits (400) may include a first matching circuit (401) connected between a first power amplifier (301) and a first electrode (501) and correcting a waveform of a U-phase output voltage provided from the first power amplifier (301), a second matching circuit (402) connected between a second power amplifier (302) and a second electrode (502) and correcting a waveform of a V-phase output voltage provided from the second power amplifier (302), and a third matching circuit (403) connected between a third power amplifier (303) and a third electrode (503) and correcting a waveform of a W-phase output voltage provided from the third power amplifier (303).

[0220] The control unit (600) can be connected to a first node (N1) provided between the node e and the first power amplifier (301), a second node (N2) provided between the first node (N1) and the second power amplifier (302), and a third node (N3) provided between the first node (N1) and the third power amplifier (303). Accordingly, the control unit (600) can detect a power value corresponding to a rectified U-phase input voltage, a power value corresponding to a rectified V-phase input voltage, and a power value corresponding to a rectified W-phase input voltage.

[0221] The control unit (600) can select one of the U-phase input voltage, the V-phase input voltage, and the W-phase input voltage. This may include determining which of the three phase input voltages is to be used to detect the power value.

[0222] When the control unit (600) selects the U-phase input voltage, the control unit can detect a power value corresponding to the rectified U-phase input voltage based on the fact that the size of the U-phase output voltage is less than or equal to the predetermined reference voltage (Vr).

[0223] In addition, when the control unit (600) selects the V-phase input voltage, it can detect a power value corresponding to the rectified V-phase input voltage based on the magnitude of the V-phase output voltage being less than or equal to a predetermined reference voltage (Vr).

[0224] In addition, when the control unit (600) selects the W-phase input voltage, it can detect a power value corresponding to the rectified W-phase output voltage based on the fact that the size of the W-phase output voltage is lower than or equal to a predetermined reference voltage (Vr).

[0225] The control unit (600) can select one of the U-phase output voltage, the V-phase output voltage, and the W-phase output voltage. This may include detecting the power value based on which of the three output voltages, or determining whether to correct the waveform of the output voltage.

[0226] When the control unit (600) selects the U-phase output voltage, the control unit (600) can control the U-phase matching circuit (400) to correct the waveform of the amplified U-phase output voltage using a power value corresponding to the rectified U-phase input voltage based on the fact that the size of the U-phase output voltage is less than or equal to a predetermined reference voltage (Vr).

[0227] In addition, when the control unit (600) selects the V-phase output voltage, the control unit (600) can control the V-phase matching circuit (400) to correct the waveform of the amplified V-phase output voltage using a power value corresponding to the rectified V-phase input voltage based on the magnitude of the V-phase output voltage being less than or equal to a predetermined reference voltage (Vr).

[0228] In addition, when the control unit (600) selects the W-phase output voltage, the control unit (600) can control the W-phase matching circuit (400) to correct the waveform of the amplified W-phase output voltage using a power value corresponding to the rectified W-phase input voltage based on the fact that the size of the W-phase output voltage is less than or equal to a predetermined reference voltage (Vr).

[0229] FIG. 18 is a graph showing a control method according to a three-phase output voltage provided from a plurality of power amplifiers (300) of a dryer (1) according to one embodiment of the present invention.

[0230] The x-axis of Fig. 18 may represent time (t), and the y-axis may represent each three-phase output voltage provided from each of the plurality of power amplifiers (300). In Fig. 18, ① means a time period during which an operation of supplying power is performed, ② means a time period during which a power value is detected, and ③ means a time period during which impedance matching or correction of the output voltage is performed.

[0231] Referring to Fig. 18, it can be confirmed that each of the three-phase output voltages in the time periods t0 to t1, t2 to t3, and t4 to t5, which are indicated by dark shading, is greater than the reference voltage (Vr). Therefore, in the time periods t0 to t1, t2 to t3, and t4 to t5, the control unit (600) can control the power amplifier (300) so that each of the three-phase output voltages is applied to the plurality of electrodes (500).

[0232] In Fig. 18, it can be confirmed that the time periods t1 to t2, t3 to t4, and t5 to t6, which are indicated by light shading, have each three-phase output voltage lower than the reference voltage (Vr). Therefore, in the time periods t1 to t2, t3 to t4, and t5 to t6, the control unit (600) can detect the power value corresponding to each rectified three-phase input voltage, and can correct the waveform of each three-phase output voltage based on the detected power value.

[0233] The control unit (600) can perform power value detection and impedance matching operations in all three-phase circuits in real time or frequently in short cycles. However, since they can also occur in long cycles, the control unit (600) does not need to perform power value detection and impedance matching operations in all three-phase circuits in real time or every time. In fact, this can be an inefficient control method.

[0234] Accordingly, the control unit (600) can predetermine the cycle for performing power value detection in each of the three-phase circuits. In addition, the control unit (600) can predetermine the cycle for performing impedance matching operation in each of the three-phase circuits.

[0235] For example, as illustrated in FIG. 18, the control unit (600) can detect a power value corresponding to the U-phase input voltage in the time period t1 to t2 and correct the waveform of the V-phase output voltage. In addition, the control unit (600) can detect a power value corresponding to the V-phase input voltage in the time period t3 to t4 and correct the waveform of the W-phase output voltage. In addition, the control unit (600) can detect a power value corresponding to the W-phase input voltage in the time period t5 to t6 and correct the waveform of the V-phase output voltage.

[0236] The method of controlling the three-phase circuit is not limited to that shown in Fig. 18, and the control unit (600) can perform a series of control operations based on each of the three-phase output voltages by predetermining any period or any interval.

[0237] According to one embodiment, a dryer (1) may include an AC power source (100) that supplies an input voltage; a rectifier (200) that rectifies the supplied input voltage; a power amplifier (300) that amplifies the rectified input voltage and provides an output voltage; a plurality of electrodes (500) to which the output voltage is applied; a matching circuit (400) that is connected between the power amplifier (300) and the plurality of electrodes (500) and corrects a waveform of the output voltage provided from the power amplifier (300); and at least one processor (601) that detects a power value corresponding to the rectified input voltage and obtains a magnitude of the output voltage provided from the power amplifier (300), wherein the at least one processor (601) may detect a power value corresponding to the rectified input voltage based on the magnitude of the output voltage provided from the power amplifier (300) being equal to or less than a predetermined reference voltage (Vr).

[0238] The at least one processor (601) can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the magnitude of the output voltage provided from the power amplifier (300) being greater than a predetermined reference voltage (Vr).

[0239] The at least one processor (601) can control the matching circuit (400) to correct the waveform of the output voltage based on the detected power value.

[0240] The at least one processor (601) can control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the first voltage value (V1) when the size of the supplied power is greater than the preset first power value (P1).

[0241] The at least one processor (601) controls the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the first voltage value (V1) when the size of the supplied power is greater than the preset first power value (P1), and may control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the second voltage value (V2) at any time interval, and the second voltage value (V2) may be greater than the first voltage value (V1).

[0242] The at least one processor (601) may control the power amplifier (300) to apply the output voltage to the plurality of electrodes (500) based on the fact that the size of the output voltage is greater than the second voltage value (V2) when the size of the supplied power is less than the preset second power value (P2), and the preset second power value (P2) may be less than the preset first power value (P1).

[0243] The at least one processor (601) may control the power amplifier (300) to determine a third voltage value that is greater than or equal to the first voltage value (V1) and less than or equal to the second voltage value (V2) based on the magnitude of the supplied power when the magnitude of the supplied power is less than or equal to the first power value (P1) and greater than or equal to the second power value (P2), and to apply the output voltage to the plurality of electrodes (500) based on the magnitude of the output voltage being greater than the determined third voltage value, and the preset second power value (P2) may be less than the preset first power value (P1), and the second voltage value (V2) may be greater than the first voltage value (V1).

[0244] The at least one processor (601) can identify whether a power value that has already been detected exists based on the magnitude of the output voltage being less than or equal to the predetermined reference voltage (Vr), and if it is identified that the power value that has already been detected exists, it can control the matching circuit (400) to correct the waveform of the output voltage based on the power value that has already been detected, and if it is identified that the power value that has already been detected does not exist, it can detect a power value corresponding to the rectified input voltage.

[0245] The at least one processor (601) can detect a power value corresponding to the rectified input voltage if it is determined that the already detected power value does not exist.

[0246] The above at least one processor (601) can obtain a first operation time during which an operation of applying the output voltage is performed.

[0247] The at least one processor (601) may decrease the predetermined reference voltage (Vr) based on the fact that the acquired first operation time is less than the time required to apply the output voltage corresponding to the magnitude of the supplied power, and may increase the predetermined reference voltage (Vr) based on the fact that the acquired first operation time is more than the time required to apply the output voltage corresponding to the magnitude of the supplied power.

[0248] The at least one processor (601) may determine the amount by which the predetermined reference voltage (Vr) is increased or decreased based on the difference between the acquired first operation time and the time required to apply the output voltage corresponding to the amount of the supplied power.

[0249] The above at least one processor (601) can obtain a second operation time during which the operation of detecting the power value is performed.

[0250] The at least one processor (601) may increase the predetermined reference voltage (Vr) based on the acquired second operation time being less than the time required to detect the power value, and may decrease the predetermined reference voltage (Vr) based on the acquired second operation time being greater than the time required to detect the power value.

[0251] The at least one processor (601) can determine the amount by which the predetermined reference voltage (Vr) is increased or decreased based on the difference between the acquired second operation time and the time required to detect the power value.

[0252] The above at least one processor (601) can obtain a third operation time during which an operation of correcting the waveform of the output voltage is performed.

[0253] The at least one processor (601) may increase the predetermined reference voltage (Vr) based on the acquired third operation time being less than the time required to correct the waveform of the output voltage, and may decrease the predetermined reference voltage (Vr) based on the acquired third operation time being greater than the time required to correct the waveform of the output voltage.

[0254] The at least one processor (601) can determine the amount by which the predetermined reference voltage (Vr) is increased or decreased based on the difference between the acquired third operation time and the time required to correct the waveform of the output voltage.

[0255] The input voltage may include a U-phase input voltage, a V-phase input voltage, and a W-phase input voltage, and the power amplifier (300) includes a first power amplifier (301) that amplifies the U-phase input voltage to provide a U-phase output voltage, a second power amplifier (302) that amplifies the V-phase input voltage to provide a V-phase output voltage, and a third power amplifier (303) that amplifies the W-phase input voltage to provide a W-phase output voltage, and the plurality of electrodes (500) include a first electrode (501) to which the U-phase output voltage is applied, a second electrode (502) to which the V-phase output voltage is applied, and a third electrode (503) to which the W-phase output voltage is applied, and the matching circuit (400) includes a first matching circuit (401) that is connected between the first power amplifier (301) and the first electrode (501) and corrects a waveform of the U-phase output voltage provided from the first power amplifier (301), and the second power amplifier (302) that amplifies the U-phase output voltage. A second matching circuit (402) connected between the amplifier (302) and the second electrode (502) and correcting a waveform of the V-phase output voltage provided from the second power amplifier (302), and a third matching circuit (403) connected between the third power amplifier (303) and the third electrode (503) and correcting a waveform of the W-phase output voltage provided from the third power amplifier (303) may be included, and the at least one processor (601) selects one of the U-phase input voltage, the V-phase input voltage, and the W-phase input voltage, and when the U-phase input voltage is selected, detects a power value corresponding to the rectified U-phase input voltage based on the magnitude of the U-phase output voltage being less than or equal to the predetermined reference voltage (Vr), and when the V-phase input voltage is selected, detects a power value corresponding to the rectified V-phase input voltage based on the magnitude of the V-phase output voltage being less than or equal to the predetermined reference voltage (Vr), and when the W-phase input voltage is selected,Based on the fact that the magnitude of the above W-phase output voltage is less than or equal to the predetermined reference voltage (Vr), a power value corresponding to the above rectified W-phase output voltage can be detected.

[0256] The at least one processor (601) may select one of the U-phase output voltage, the V-phase output voltage, and the W-phase output voltage, and, when the U-phase output voltage is selected, control the first matching circuit (401) to correct the waveform of the amplified U-phase output voltage using a power value corresponding to the rectified U-phase input voltage based on the magnitude of the U-phase output voltage being less than or equal to the predetermined reference voltage (Vr), and, when the V-phase output voltage is selected, control the second matching circuit (402) to correct the waveform of the amplified V-phase output voltage using a power value corresponding to the rectified V-phase input voltage based on the magnitude of the V-phase output voltage being less than or equal to the predetermined reference voltage (Vr), and, when the W-phase output voltage is selected, control the third matching circuit (403) to correct the waveform of the amplified W-phase output voltage using a power value corresponding to the rectified W-phase input voltage based on the magnitude of the W-phase output voltage being less than or equal to the predetermined reference voltage (Vr).

[0257] A method for controlling a dryer (1) according to one embodiment may include: supplying an input voltage through an AC power source (100); rectifying the supplied input voltage through a rectifier (200); amplifying the rectified input voltage through a power amplifier (300) to provide an output voltage; detecting a power value corresponding to the rectified input voltage based on whether the magnitude of the output voltage is lower than or equal to a predetermined reference voltage (Vr); controlling a matching circuit (400) to correct a waveform of the output voltage based on the detected power value; and controlling the power amplifier (300) to apply the output voltage to a plurality of electrodes (500) based on whether the magnitude of the output voltage is higher than the predetermined reference voltage (Vr).

[0258] Accordingly, there is an effect that the circuit of the dielectric heating type dryer (1) driven by high output and high voltage can be driven while the circuit elements such as sensors can operate normally.

[0259] In addition, by optimizing the section for supplying power and the section for detecting the power value according to the size of the output voltage, it is possible to solve the noise problem when driven at high frequency and high output while simultaneously supplying power efficiently.

[0260] 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 the processor (601), may generate program modules to perform the operations of the disclosed embodiments.

[0261] 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.

[0262] According to one embodiment, the method according to various embodiments disclosed in the present 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., downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as a manufacturer's server, an application store's server, or a memory (602) of an intermediary server.

[0263] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0264] The above illustrates and describes specific embodiments. However, the invention is not limited to the above-described embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. AC power supply that supplies input voltage; A rectifier for rectifying the supplied input voltage; A power amplifier that amplifies the rectified input voltage and provides an output voltage; A plurality of electrodes to which the above output voltage is applied; A matching circuit connected between the power amplifier and the plurality of electrodes and correcting the waveform of the output voltage provided from the power amplifier; and At least one processor for detecting a power value corresponding to the rectified input voltage and obtaining a size of the output voltage provided from the power amplifier; At least one processor of the above, A dryer that detects a power value corresponding to the rectified input voltage based on the size of the output voltage provided from the power amplifier being lower than or equal to a predetermined reference voltage.

2. In paragraph 1, At least one processor of the above, A dryer that controls the power amplifier to apply the output voltage to the plurality of electrodes based on the magnitude of the output voltage provided from the power amplifier being greater than a predetermined reference voltage.

3. In paragraph 1, At least one processor of the above, A dryer that controls the matching circuit to correct the waveform of the output voltage based on the detected power value.

4. In paragraph 1, At least one processor of the above, A dryer that controls the power amplifier to apply the output voltage to the plurality of electrodes based on the fact that the size of the output voltage is greater than the first voltage value when the size of the supplied power is greater than the preset first power value.

5. In paragraph 4, At least one processor of the above, If the size of the supplied power is greater than the preset first power value, the power amplifier is controlled to apply the output voltage to the plurality of electrodes based on the size of the output voltage being greater than the first voltage value, and at any time interval, the power amplifier is controlled to apply the output voltage to the plurality of electrodes based on the size of the output voltage being greater than the second voltage value. A dryer wherein the second voltage value is greater than the first voltage value.

6. In paragraph 1, At least one processor of the above, If the size of the supplied power is less than a preset second power value, the power amplifier is controlled to apply the output voltage to the plurality of electrodes based on the size of the output voltage being greater than the second voltage value, A dryer wherein the second preset power value is lower than the first preset power value.

7. In paragraph 1, At least one processor of the above, If the size of the supplied power is less than or equal to a preset first power value and greater than or equal to a preset second power value, a third voltage value greater than or equal to the first voltage value and less than or equal to the second voltage value is determined based on the size of the supplied power, Controlling the power amplifier to apply the output voltage to the plurality of electrodes based on the magnitude of the output voltage being greater than the determined third voltage value; A dryer wherein the second preset power value is smaller than the first preset power value, and the second voltage value is larger than the first voltage value.

8. In paragraph 2, At least one processor of the above, Based on the fact that the size of the output voltage is less than or equal to the predetermined reference voltage, it is identified whether a power value that has already been detected exists, If it is identified that the already detected power value exists, the matching circuit is controlled to correct the waveform of the output voltage based on the already detected power value, A dryer that detects a power value corresponding to the rectified input voltage when it is identified that the above-detected power value does not exist.

9. In paragraph 2, At least one processor of the above, A dryer for obtaining a first operation time during which an operation of applying the above output voltage is performed.

10. In paragraph 9, At least one processor of the above, The above-determined reference voltage is reduced based on the fact that the above-determined first operation time is less than the time required to apply an output voltage corresponding to the size of the supplied power, A dryer that increases the predetermined reference voltage based on the fact that the acquired first operation time exceeds the time required to apply the output voltage corresponding to the size of the supplied power.

11. In paragraph 10, At least one processor of the above, A dryer that determines the amount by which the predetermined reference voltage is increased or decreased based on the difference between the acquired first operation time and the time required to apply the output voltage corresponding to the amount of the supplied power.

12. In paragraph 1, At least one processor of the above, A dryer for obtaining a second operation time during which an operation of detecting the above power value is performed.

13. In paragraph 12, At least one processor of the above, increasing the predetermined reference voltage based on the fact that the acquired second operation time is less than the time required to detect the power value; A dryer that reduces the predetermined reference voltage based on the obtained second operation time exceeding the time required to detect the power value.

14. In paragraph 13, At least one processor of the above, A dryer that determines the amount by which the predetermined reference voltage is increased or decreased based on the difference between the acquired second operation time and the time required to detect the power value.

15. In paragraph 3, At least one processor of the above, A dryer for obtaining a third operation time during which an operation for correcting the waveform of the above output voltage is performed.

Images