Home appliance

Abstract

The present invention provides a home appliance in which the output of a harmonic drive inverter can be precisely measured on the basis of a resonance parameter. The home appliance includes: a load circuit including at least one heating coil; an inverter circuit that includes switching elements and supplies a current to the load circuit according to switching operations of the switching elements; a current sensing circuit for sensing a resonance current output from the inverter circuit; a pulse generation circuit for generating a pulse signal used to measure the phase difference between the resonance current and a switching voltage of the inverter circuit on the basis of the resonance current; and a controller which measures the phase difference on the basis of the pulse signal and measures the output power of the load circuit on the basis of the phase difference.

Description

home appliances

[0001] The present invention relates to a home appliance, and more particularly, to a home appliance including an induction heating cooktop.

[0002]

[0003] Induction ranges, which utilize induction heating technology, are gaining attention as next-generation cooking appliances that can replace gas ranges due to their advantages such as high heating efficiency, fast heating speed, stability, and convenience.

[0004] Induction heating cooktops feature heating coils made of Ritz wire. These cooktops heat induction-specific containers by placing them on a designated burner. This method requires containers to be placed in a specific location, and any slight misalignment reduces heating efficiency.

[0005] Accordingly, research and development are underway for "All Free" induction heating technology. This technology enables heating of induction containers in various locations without requiring a fixed area on the induction heating plate. It also offers the advantage of being able to heat containers of various sizes and multiple containers with three or more zones.

[0006] While there are various methods for measuring output in an induction heating system, precise measurement of the output of individual inverters is a crucial foundational parameter for controlling the system and minimizing interference noise. The existing shunt method requires extensive tuning and requires re-tuning if the measurement pattern on the inverter PCB changes or the coil is changed.

[0007] In particular, in the case of harmonic drive inverters, there is a problem that measuring small voltages using a shunt method in an environment where a lot of noise is generated is likely to cause errors in hardware output measurement.

[0008] Prior art 1 (EP4210438) adjusts output power based on phase difference. However, due to the use of multiple comparators and multiple reference voltages, errors occur at low current and voltage points. In particular, in high-frequency inverters, the transition period is a large proportion of the overall phase margin period, which reduces the distinguishability of phase margin data.

[0009]

[0010] The present invention provides a home appliance capable of precisely measuring the output of a harmonic drive inverter.

[0011] In addition, the present invention provides a home appliance capable of detecting only the resonant current output from an inverter circuit and measuring the phase difference between the resonant current and the switching voltage of the inverter circuit.

[0012] In addition, the present invention provides a home appliance that can reduce accumulated errors occurring in a comparator by using only one comparator of a pulse generation circuit used to measure a phase difference.

[0013] In addition, the present invention provides a home appliance capable of accurately measuring a phase difference based on a pulse signal according to the start point of a switching frequency and a resonant current.

[0014] In addition, the present invention provides a home appliance capable of measuring a resonant voltage based on an input voltage and a duty ratio of an inverter circuit.

[0015] In addition, the present invention provides a home appliance capable of accurately measuring the output power of a load based on resonant current, resonant voltage, and phase difference.

[0016] In addition, the present invention provides a home appliance capable of driving a load with a target power by adjusting at least one of a switching frequency and a duty ratio of an inverter circuit according to the output power of the load.

[0017] The problems to be solved according to one embodiment of this specification are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0018]

[0019] A home appliance according to one embodiment of the present invention precisely measures the output of a harmonic drive inverter.

[0020] Specifically, the home appliance generates a pulse signal based on a resonant current output from an inverter circuit, measures a phase difference based on the pulse signal, and measures the output power of a load circuit based on the phase difference.

[0021] A home appliance according to one embodiment of the present invention detects only the resonant current output from an inverter circuit and measures the phase difference between the resonant current and the switching voltage of the inverter circuit.

[0022] Specifically, the home appliance defines the start point of the internal PWM count as the start point of the phase margin, defines the falling edge interrupt of the pulse signal as the end point of the phase margin, and calculates the phase difference based on the start and end points of the phase margin.

[0023] A home appliance according to one embodiment of the present invention can reduce accumulated errors occurring in a comparator.

[0024] Specifically, the appliance includes only one comparator that compares a voltage according to the resonant current with a reference voltage in a pulse generation circuit used to measure the phase difference and generates a pulse signal.

[0025] An electrical appliance according to one embodiment of the present invention measures a phase difference based on a pulse signal according to a start point of a switching frequency and a resonant current.

[0026] Specifically, the home appliance defines the count start point of the switching frequency as the phase margin start point, defines the falling edge interrupt of the pulse signal as the phase margin end point, and calculates the phase difference based on the phase margin start and end points.

[0027] A home appliance according to one embodiment of the present invention measures a resonant voltage based on an input voltage and a duty ratio of an inverter circuit.

[0028] Specifically, the home appliance calculates the resonant voltage by multiplying the duty ratio by the input voltage of the inverter circuit.

[0029] Additionally, the appliance measures the output power of the load based on the resonant current, resonant voltage, and phase difference.

[0030] Additionally, the home appliance drives the load at a target power by adjusting at least one of the switching frequency and duty ratio of the inverter circuit according to the measured output power of the load.

[0031]

[0032] As described above, the present invention detects only the resonant current output from the inverter circuit and measures the phase difference between the resonant current and the switching voltage of the inverter circuit, so that the output of the harmonic drive inverter can be precisely measured.

[0033] In addition, since the present invention measures the phase difference using only one comparator of the pulse generation circuit, the accumulated error occurring in the comparator can be reduced.

[0034] In addition, the present invention can accurately measure the phase difference between the resonant current and the switching voltage of the inverter circuit based on the pulse signal according to the start point of the switching frequency and the resonant current.

[0035] In addition, the present invention can measure the resonant voltage based on the input voltage of the power supply and the duty ratio of the inverter circuit.

[0036] In addition, the present invention can accurately measure the output power of a load based on the resonant current, resonant voltage, and phase difference.

[0037] In addition, the present invention can drive a load with a target power by adjusting at least one of the switching frequency and duty ratio of the inverter circuit according to the output power of the load.

[0038] In addition, the present invention measures the output power of a load by detecting only the resonant current in the hardware aspect and measuring the resonant voltage and phase in the software aspect, so it can be robust to noise compared to existing technologies that use shunt resistors.

[0039] In addition, the present invention measures the output power of the load by detecting only the resonant current in the hardware aspect and measuring the resonant voltage and phase in the software aspect, so that the power of the load can be accurately measured regardless of changes in the heating coil or changes in the inverter PCB pattern.

[0040] In addition, the present invention can improve the reliability of the switch drive of the inverter circuit by controlling at least one of the switching frequency and duty ratio of the inverter circuit based on the power of the measured load.

[0041] In addition, the present invention measures the power of a load by utilizing the resonant current resulting from current conversion of the current supplied to the load in the inverter circuit, thereby preventing the influence of noise due to the resistance of the ground voltage terminal.

[0042] In addition, the present invention can reduce the influence of noise compared to the existing technology of measuring input current using a shunt resistor, thereby improving the reliability of high-frequency driving of switching elements of an inverter circuit.

[0043] In addition, since the present invention can accurately measure the power of a load even when the container is changed to a ferromagnetic or weakly magnetic material, it is possible to drive the inverter circuit at an appropriate switching frequency depending on the container material.

[0044] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0045]

[0046] FIG. 1 is an exploded perspective view showing a disassembled state of a cooktop in a home appliance according to one embodiment of the present invention.

[0047] Figure 2 is a drawing showing a plan view of the cooktop illustrated in Figure 1 and the configuration of the PCB pattern coil assembly.

[0048] FIG. 3 is a drawing showing an inverter circuit and block diagram of a home appliance according to one embodiment of the present invention.

[0049] Fig. 4 is a diagram showing the pulse generation circuit of Fig. 3.

[0050] Figure 5 is a waveform diagram showing the operation of the home appliance of Figure 3.

[0051] Figure 6 is an example of calculating the phase difference using the switching frequency count value.

[0052] FIG. 7 is a diagram illustrating an inverter circuit and a load circuit in a home appliance according to one embodiment of the present invention.

[0053]

[0054] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0055] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0056] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, these embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. Therefore, the present invention is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutes included within the technical spirit and scope of the present invention, as well as substitutions or additions of the components of one embodiment with those of another embodiment.

[0057] The attached drawings are only intended to facilitate understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention. In the drawings, the components may be expressed in an exaggerated size or thickness for convenience of understanding, etc., but the scope of protection of the present invention should not be construed as being limited due to this.

[0058] The terminology used in this specification is only used to describe specific implementations or examples and is not intended to limit the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the specification, terms such as "comprises" and "consists of" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification. In other words, it should be understood that terms such as "comprises" and "consists of" in the specification do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0059] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0060] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0061] When a component is referred to as being "above" or "below" another component, it should be understood that it is not only positioned directly above that other component, but that there may also be other components present in between.

[0062] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0063] For example, embodiments of the heating coil assembly are described herein in which the heating coil assembly is used in a cooking appliance. However, in other embodiments, the heating coil assembly may be applied to other appliances requiring induction heating.

[0064] For example, a heating coil assembly may be mounted on a washing machine and used to heat the water tank, drum, or wash tub inside the washing machine, or to heat the wash water.

[0065] As another example, the heating coil assembly may be mounted on a water purifier and used to heat a hot water pipe or tank.

[0066] As another example, the heating coil assembly may be mounted on a clothes dryer or clothes care appliance and used to heat the air for drying clothes.

[0067] As another example, a heating coil assembly may be mounted on an electric kettle or rice cooker and used to heat liquid or food inside the appliance.

[0068]

[0069] [Overall structure of an induction heating cooktop]

[0070] FIG. 1 is an exploded perspective view showing an exploded state of an induction heating cooktop (100) in a home appliance according to one embodiment of the present invention.

[0071] According to one embodiment of the present invention, a home appliance may be an oven range type in which a cooktop (100) is positioned on the upper side and an oven section is positioned on the lower side. The present invention is not limited thereto, and may be configured as a home appliance in which a cooktop (100) is provided alone.

[0072] Referring to FIG. 1, a home appliance according to an embodiment of the present invention includes an induction heating cooktop (100). The induction heating cooktop (100) may include a case (110) and a top plate (120).

[0073] According to the present embodiment, the exterior of the cooktop (100) can be formed by a case (110) and a top plate (120). The case (110) is placed below the top plate (120) and can form the front, back, side, and bottom surfaces of the cooktop (100). The top plate (120) is placed on the top of the cooktop (100) and can form the upper exterior surface of the cooktop (100). The top plate (120) can be formed of ceramic glass for holding a cooking vessel.

[0074] A receiving space may be formed inside the case (110). The receiving space formed inside the case (110) may be opened upward. As an example, the case (110) may be formed in a hexahedral shape with an open upper side. Various internal components constituting the cooktop (100) may be accommodated in the receiving space surrounded by the top plate (120) and the case (110).

[0075] Additionally, a PCB pattern coil assembly (140) may be placed on the lower side of the top plate (120) in the cooktop (100). The PCB pattern coil assembly (140) may be formed integrally with at least one heating coil for heating the cooking vessel through induction heating and at least one detection coil for detecting the cooking vessel.

[0076] For example, the PCB pattern coil assembly (140) may be configured in multiple pieces depending on the size of the top plate (120) of the cooktop (100). For example, if the top plate (120) is divided into three left areas, a center area, and a right area, three PCB pattern coil assemblies (140) may be placed on the lower side of the corresponding areas. Each of the PCB pattern coil assemblies (140) may be formed in a different size appropriate for the sizes of the left area, the center area, and the right area. Each of the PCB pattern coil assemblies (140) corresponding to each area may be driven independently.

[0077] The PCB pattern coil assembly (140) may be formed as an integrated unit including a heating coil for induction heating, a sensing coil for container detection, a temperature sensor for temperature detection, and a terminal for connection with other components. The PCB pattern coil assembly (140) may be divided into a plurality of unit blocks. For example, one heating coil may be arranged in one unit block. For example, at least two sensing coils may be arranged in one unit block. For example, two sensing coils may be arranged between one unit block and another unit block, straddling two unit blocks.

[0078] In addition, a supporter (150) may be placed on the lower side of the PCB pattern coil assembly (140) in the cooktop (100). The supporter (150) may form a framework inside the cooktop (100) to support various internal components constituting the cooktop (100). As an example, the supporter (150) may be formed in a hexahedral shape with an open lower side. For example, the supporter (150) may be formed in a shape that is roughly a case (110) turned upside down, but may be formed to have a size slightly smaller than the case (110).

[0079] According to the present embodiment, the accommodation space can be formed inside the supporter (150), and can be formed as a space surrounded by the bottom of the case (110) and the supporter (150). Various internal components constituting the cooktop (100) can be accommodated inside the supporter (150).

[0080] For example, the inside of the supporter (190) may accommodate a resonance PCB assembly (160) in which capacitors used for resonance or oscillation are mounted, an inverter PCB assembly (170) in which switching elements for applying current to a heating coil for induction heating are mounted, a fan (180) for cooling the heat of internal components, an EMI filter (190) for filtering and blocking various noises mixed in the power supply, and a control PCB assembly in which a controller for controlling the overall operation of the cooktop (100) and circuits for container detection are mounted.

[0081] According to the present embodiment, the supporter (150) can also provide a base function of the PCB pattern coil assembly (140). More specifically, a ferrite core can be installed on the upper side of the supporter (150), the PCB pattern coil assembly (140) can be installed on the upper side of the ferrite core, and a top plate (120) can be installed on the upper side of the PCB pattern coil assembly (140).

[0082] In addition, the cooktop (100) may be equipped with a control panel (130). The control panel (130) may be placed on an area of ​​the upper surface of the top plate (120). The control panel (130) may be equipped with a user interface (UI) including a control icon for controlling the operation of the cooktop (100) by touch and a display for indicating the operating status of the cooktop (100).

[0083]

[0084] [PCB pattern coil assembly]

[0085] FIG. 2 is a drawing showing a plan view of the cooktop (100) illustrated in FIG. 1 and the configuration of the PCB pattern coil assembly (140).

[0086] Referring to FIG. 2, the cooktop (100) may include a case (110), a supporter (150), and a PCB pattern coil assembly (140). The PCB pattern coil assembly (140) is provided to configure a heating coil (142) for induction heating of the cooktop (100) and a detection coil (143) for detecting a cooking vessel, and may be placed in a receiving space inside the cooktop (100).

[0087] A supporter (150) may be placed on the upper part of the case (110), a PCB pattern coil assembly (140) may be placed on the upper part of the supporter (150), and a top plate (120) may be placed on the upper part of the PCB pattern coil assembly (140).

[0088] The PCB pattern coil assembly (140) may include a plurality of PCB pattern coil assemblies (140) depending on the size and shape of the cooktop (100). In the present embodiment, the cooktop (100) is divided into a left region, a center region, and a right region, and is exemplified by including three PCB pattern coil assemblies (140). Each PCB pattern coil assembly (140) may include a plurality of heating coils (142) and a plurality of sensing coils (143).

[0089] Each PCB pattern coil assembly (140) can be divided into a plurality of unit blocks (141). The plurality of unit blocks (141) can be arranged in a matrix form. For example, at least one heating coil (142) can be arranged in one unit block (141). For example, at least two sensing coils (143) can be arranged in one unit block (141). In addition, at least two sensing coils (143) can be arranged between one unit block (141) and another unit block (141) to span two unit blocks.

[0090] Each heating coil (142) and sensing coil (143) formed on the PCB pattern coil assembly (140) may be arranged in a pattern shape on the substrate. For example, the heating coil (142) may be formed in a polygonal, for example, square, rectangular, or hexagonal pattern. Alternatively, the heating coil (142) may be formed in a circular pattern. For example, the sensing coil (143) may be formed in a circular, square, rectangular, or hexagonal pattern.

[0091] Additionally, the PCB pattern coil assembly (140) may be formed with at least one heating coil terminal (145), at least one sensing coil terminal (146), at least one heating coil wiring (147), at least one sensing coil wiring (148), and at least one via. The heating coil terminal (145) is electrically connected to the heating coil (142) through the heating coil wiring (147) and is electrically connected to the resonant PCB assembly (160) and the inverter PCB assembly (170). The sensing coil terminal (146) is electrically connected to the sensing coil (143) through the sensing coil wiring (148) and is electrically connected to the resonant PCB assembly (160) and the control PCB assembly.

[0092] In this way, not only a heating coil (142) but also a sensing coil (143) can be formed in the unit block (141) of the PCB pattern coil assembly (140). In the unit block (141), a plurality of sensing coils (143) are arranged along the front-back direction, and a plurality of sensing coils (143) are also arranged in the lateral direction.

[0093] The PCB pattern coil assembly (140) may include a PCB having a heating coil (142) patterned thereon (hereinafter referred to as a “heating coil PCB”) and a PCB having a sensing coil (143) patterned thereon (hereinafter referred to as a “sensing coil PCB”). The PCB pattern coil assembly (140) may be formed in a form in which the heating coil PCB and the sensing coil PCB are stacked vertically. For example, the heating coil PCB may be formed in a form in which 10 to 12 layers are stacked, and the heating coils (142) between the layers may be electrically connected through vias. For example, the sensing coil PCB may be formed in a form in which two layers are stacked, and the sensing coils (143) between the layers may be electrically connected through vias.

[0094] Additionally, at least one of the heating coil PCB and the sensing coil PCB may be provided in a form in which coils are patterned on both sides of the substrate. In the present embodiment, it is exemplified that the heating coil (142) is patterned on both sides of the heating coil PCB, and the sensing coil (143) is patterned on both sides of the sensing coil PCB.

[0095] Each sensing coil (143) may be positioned to overlap with each heating coil (142) forming region, as illustrated in FIGS. 2 and 3. Additionally, each sensing coil (143) may be positioned to overlap between two adjacent heating coil (142) forming regions.

[0096] In this embodiment, it is exemplified that two sensing coils (143) are respectively arranged inside each heating coil (142) forming region, and two sensing coils (143) are respectively arranged between two heating coils (142) adjacent in the front-back direction. In addition, a temperature sensor (144) may be provided in the PCB pattern coil assembly (140). For example, the temperature sensor (144) may be arranged at the center of each sensing coil (143).

[0097] As an example, the PCB pattern coil assembly (140) may be provided in a form in which a heating coil (142), a detection coil (143), and a temperature sensor (144) are integrally formed. For example, the PCB pattern coil assembly (140) may be formed in a form in which a heating coil PCB provided with a heating coil (142) and a detection coil PCB provided with a detection coil (143) and a temperature sensor (144) are laminated. The PCB pattern coil assembly (140) may be provided in a form including one or more pattern coil PCBs.

[0098] In this way, the PCB pattern coil assembly (140) has a structure in which a plurality of heating coils (142) for induction heating using a pattern printed on the PCB and a plurality of detection coils (143) for detecting a cooking vessel placed on a ceramic glass are formed as an integral part. The number of heating coils (142) and detection coils (143) can be determined according to the size of the cooktop (100).

[0099] For example, an integrated PCB pattern coil assembly (140) may include heating coil patterns arranged in a ten-layer structure, sensing coil patterns arranged in a two-layer structure, and an insulating material disposed between each heating coil pattern and each sensing coil pattern to insulate them. The insulating material may be formed by curing a prepreg composed of a thermosetting resin and glass fiber, which are generally used to form a printed circuit board. As an example, an applicable thermosetting resin is preferably an epoxy resin series, and specifically, FR-4 can be applied.

[0100] In this way, the insulating material formed through the prepreg can be placed between each heating coil pattern arranged in a layered structure to insulate them, and can be placed between each sensing coil pattern to insulate them. In addition, the insulating material can be configured to fill in areas where patterns are not formed, such as the heating coil pattern and the sensing coil pattern, to form a layered structure of individual layers.

[0101] Therefore, based on the heating coil pattern and the sensing coil pattern, the PCB pattern coil assembly (140) can have a layered structure having a total of 12 layers from the first layer forming the uppermost side in the vertical direction to the 12th layer forming the lowermost layer.

[0102] In this way, the heating coil pattern and the sensing coil pattern according to the embodiment of the present invention are formed as an integrated PCB pattern coil assembly formed of multiple layers, thereby contributing to the simplification of processes such as masking, printing, and etching.

[0103]

[0104] [Configuration of home appliances for power measurement]

[0105] Fig. 3 is a diagram showing an inverter circuit and block diagram of a home appliance according to one embodiment of the present invention. Fig. 4 is a diagram showing the pulse generation circuit of Fig. 3. Fig. 5 is a waveform diagram showing the operation of the home appliance of Fig. 3. Fig. 6 is an exemplary diagram for calculating a phase difference using a switching frequency count value.

[0106] In IH (Induction Heating) appliances, the load is the induction vessel, due to the nature of the application. Induction vessels are broadly categorized into ferromagnetic and weakly magnetic types, each with different characteristics. The appliance measures the output power during operation by positioning the vessel at the heating coil location and controls the output power by adjusting at least one of the switching frequency and duty ratio of the inverter circuit based on the output power. Output power can be adjusted differently for ferromagnetic and weakly magnetic types.

[0107] For example, the home appliance can drive the heating coil (142) with a lower power for a ferromagnetic container with strong magnetism than for a weakly magnetic container with weak magnetism. The power intensity according to the material of the container or the power intensity according to the change value of the equivalent resistance of the detection coil can be stored in the memory, and the controller (500) can drive the heating coil (142) with a power intensity corresponding to the container after determining the material of the container.

[0108] The criteria for distinguishing magnetic materials are determined by the formation of a magnetic permeability. The magnetic permeability is the ratio of the permeability in the medium to the permeability in a vacuum, and represents the multiple of the vacuum permeability.

[0109] In this specification, a ferromagnetic material can be defined as a material with a relative magnetic permeability greater than 1. A ferromagnetic material possesses strong magnetism, and its magnetism can change depending on temperature and an external magnetic field, and it retains this magnetism even when the external magnetic field is removed. Iron, cobalt, and nickel are representative ferromagnetic materials.

[0110] In this specification, a weakly magnetic material can be defined as a material with a relative magnetic permeability equal to or slightly greater than 1. A weakly magnetic material has weak magnetism and is susceptible to changes in magnetism depending on external magnetic fields or temperature. Representative weakly magnetic materials include aluminum, platinum, and platinum.

[0111] Therefore, in order to accurately drive the heating coil with the target power suitable for the material of the container, the appliance must be able to accurately measure the output power of the load.

[0112] An embodiment of the present invention provides a home appliance capable of precisely measuring the output of a harmonic drive inverter based on a resonance parameter including at least one of a resonance current, a resonance voltage, and a phase.

[0113] Referring to FIG. 3, a home appliance according to one embodiment includes a rectifier circuit (310), an inverter circuit (320), a current detection circuit (330, 360), a load circuit (350), a pulse generation circuit (370), a control panel (130), a controller (500), and an inverter driving circuit (510).

[0114] The rectifier circuit (310) may include a plurality of diode elements (312) and a DC link capacitor (C1). The diode elements (312) rectify the input voltage (Vin) supplied from the power supply (302) and output a voltage having a pulsating waveform. The DC link capacitor (C1) smoothes the voltage output from the diode elements (312) and outputs a DC link voltage.

[0115] The inverter circuit (320) supplies a resonant current (Ir) to the heating coil in the load circuit (350) based on the DC link voltage supplied from the DC link capacitor (C1). The inverter circuit (320) may include a plurality of switching elements, for example, a first switching element (DS1) and a second switching element (DS2). The first switching element (DS1) and the second switching element (DS2) are connected in series with each other.

[0116] The inverter circuit (320) supplies resonant current to the load circuit (350) through the switching operation of the first switching element (DS1) and the second switching element (DS2). The resonant frequency of the resonant current is determined by the capacitance value of the heating coil of the load circuit (350) and the capacitance value of the resonant capacitor.

[0117] The first switching element (DS1) and the second switching element (DS2) can be alternately turned on and off by the first switching signal (S1) and the second switching signal (S2) supplied from the inverter driving circuit (510). The alternate turning on and turning off of the first switching element (DS1) and the second switching element (DS2) can be referred to as switching driving of the first switching element (DS1) and the second switching element (DS2).

[0118] A resonant current (Ir) is generated by the switching operation of the first switching element (DS1) and the second switching element (DS2). When the resonant current (Ir) is supplied to the heating coil, an eddy current flows in the container provided on top of the heating coil, thereby heating the container.

[0119] The inverter circuit (320) further includes a first snubber capacitor (CS1) and a second snubber capacitor (CS2). The first snubber capacitor (CS1) is connected in parallel with the first switching element (DS1). The second snubber capacitor (CS2) is connected in parallel with the second switching element (SW2). The first snubber capacitor (CS1) and the second snubber capacitor (CS2) are connected in series with each other.

[0120] The first snubber capacitor (CS1) and the second snubber capacitor (CS2) serve to reduce power loss due to hard switching that occurs when the first switching element (DS1) and the second switching element (DS2) are turned off.

[0121] The control panel (130) may be equipped with a user interface including a control icon for controlling the operation of the home appliance by touch and a display for indicating the operating status of the home appliance. The user can input a target heating intensity through the control panel (130).

[0122] The load circuit (350) includes at least one heating coil, at least one resonant capacitor, and at least one relay. Here, the at least one heating coil, the at least one resonant capacitor, and the at least one relay may be optionally connected in series or parallel.

[0123] The current sensing circuit includes a current converter (330) and a stabilizing circuit (360). The current converter (330) may include a primary winding (T1) and a secondary winding (T2). The primary winding (T1) may be connected between an inverter circuit (320) and a heating coil, and the secondary winding (T2) may be connected to a stabilizing circuit (360). The number of coil turns of the primary winding (T1) and the number of coil turns of the secondary winding (T2) are inversely proportional to the magnitude of the current flowing in the primary winding (T1) and the secondary winding (T2), respectively. The number of coil turns of the secondary winding (T2) may be greater than the number of coil turns of the primary winding (T1). Accordingly, the magnitude of the current flowing in the secondary winding (T2) may be less than the magnitude of the current flowing in the primary winding (T1).

[0124] A current having a smaller magnitude than the resonant current (Ir) flowing in the primary winding (T1) can flow in the secondary winding (T2). The current flowing in the secondary winding (T2), i.e. the resonant current whose magnitude has been converted, can be supplied to the pulse generation circuit (370) through the stabilization circuit (360).

[0125] A stabilizing circuit (360) is connected in parallel to a current converter (330). The stabilizing circuit (360) includes at least one resistor and a stabilizing capacitor connected in parallel to the current converter (330). One end of the at least one resistor is connected to a ground voltage terminal and the other end is connected to an output terminal from which a resonant current (Ir) is output. The stabilizing capacitor is connected in parallel with the at least one resistor, and one end is connected to the ground voltage terminal and the other end is connected to an output terminal. The output terminal of the stabilizing circuit (360) is connected to a pulse generating circuit (370).

[0126] Referring to Fig. 4, the pulse generation circuit (370) generates a pulse signal (S_PM) based on the resonant current (Ir) output from the current detection circuit and supplies the pulse signal (S_PM) to the controller (500). The pulse signal (S_PM) is used to measure the phase difference between the resonant current (Ir) and the switching voltage (DS2_Vds) of the second switching element (DS2) of the inverter circuit (320) within the controller (500).

[0127] The pulse generation circuit (370) includes a first diode (D31) connected to the output terminal of the current detection circuit, a first resistor (R31) connected in series to the first diode (D31), a second diode (D32) having one end connected to a power supply voltage (5 V) terminal and the other end connected to the first resistor (R31), and a second resistor (R32) having one end connected to the first resistor (R31) and the other end connected to a ground voltage terminal.

[0128] In addition, the pulse generation circuit (370) includes a third resistor (R33) connected in series with the first resistor (R31), a comparator (CP1) having a first input terminal (+) connected to the third resistor (R33) and a second input terminal (-) connected to a reference voltage (Vref) terminal, and a fourth resistor (R34) connected between the output terminal of the comparator (CP1) and the first input terminal (+).

[0129] In addition, the pulse generation circuit (370) further includes first and second reference resistors (R36, R35) connected in series between the power supply voltage terminal and the ground voltage terminal, and a reference capacitor (31) connected between the node between the first and second reference resistors (R36, R35) and the ground voltage terminal. The node between the first and second reference resistors (R36, R35) is connected to the second input terminal (-) of the comparator (CP1) as a reference voltage terminal. In this way, the pulse generation circuit (370) generates a pulse signal using one comparator. This can reduce the accumulated error occurring in the comparator.

[0130] Referring to FIGS. 3 to 6, the controller (500) controls the inverter drive circuit (510) to drive the load circuit (350) with the target intensity received from the control panel (130). The controller (500) controls the switching of the switching elements of the inverter drive circuit (510).

[0131] The controller (500) measures the phase margin based on the pulse signal (S_PM) output from the pulse generation circuit (370) and the switching frequency count value, and measures the phase difference based on the phase margin.

[0132] The controller (500) defines the internal PWM count start point as the phase margin start point, defines the falling edge interrupt of the pulse signal as the phase margin end point, and calculates the phase difference based on the phase margin start and end points. For example, it can be calculated as "phase margin (PM) = (switching frequency count value / 2) + dead time - count value at the time of interrupt occurrence". For example, it is calculated as PM = 1333 / 2 + 60 - 600 = 76. The phase is calculated by multiplying 360 degrees by the phase margin (PM) and dividing by the switching frequency. Here, the phase represents the phase difference between the resonant current and the switching voltage.

[0133] The controller (500) calculates the resonant voltage as a value obtained by multiplying the input voltage (Vin) by the on-time duty of the switching element. The controller (500) calculates the resonant current using a first-order regression equation based on the value measured by the current detection circuit, and measures the resonant current value output to the inverter circuit (320).

[0134] The controller (500) controls the resonant voltage (VINPUT x Duty), the average resonant current (I L_avg ), and the phase difference (θ) is used to measure the output power of the load circuit. For example, the output power is calculated by Power = VINPUT x Duty x ILavg x cosΘ. The controller (500) can calculate the output power at least once per system control cycle, for example, every 10 ms or 8.3 ms.

[0135] The controller (500) controls the switching operation of the inverter circuit by adjusting at least one of the switching frequency and duty ratio of the inverter circuit (320) according to the output power of the load circuit.

[0136] The controller (500) can control at least one relay within the load circuit (350) to activate at least one heating coil corresponding to the position of the container depending on the position of the container.

[0137] The controller (500) measures the phase difference between the resonant current and the switching voltage of the inverter circuit using only the resonant current output from the inverter circuit (320), so that the output of the harmonic drive inverter can be precisely measured.

[0138] In this way, the present invention measures the output power of the load by detecting only the resonant current in the hardware aspect and measuring the resonant voltage and phase in the software aspect, so the power of the load can be accurately measured regardless of changes in the heating coil or changes in the inverter PCB pattern.

[0139] In addition, the present invention can improve the reliability of the switch drive of the inverter circuit by controlling at least one of the switching frequency and duty ratio of the inverter circuit based on the power of the measured load.

[0140] In addition, the present invention measures the power of a load by utilizing the resonant current resulting from current conversion of the current supplied to the load in the inverter circuit, thereby preventing the influence of noise due to the resistance of the ground voltage terminal.

[0141] In addition, the present invention can reduce the influence of noise compared to the existing technology of measuring input current using a shunt resistor, thereby improving the reliability of high-frequency driving of switching elements of an inverter circuit.

[0142] In addition, since the present invention can accurately measure the power of a load even when the container is changed to a ferromagnetic or weakly magnetic material, it is possible to drive the inverter circuit at an appropriate switching frequency depending on the container material.

[0143]

[0144] [Inverter circuit and load circuit]

[0145] FIG. 7 is a diagram illustrating a rectifier circuit (310), a first inverter circuit (320a), a second inverter circuit (320b), and a load circuit (350) in a home appliance according to one embodiment of the present invention.

[0146] The rectifier circuit (310) converts an alternating voltage whose magnitude and polarity (positive voltage or negative voltage) change over time into a direct current voltage whose magnitude and polarity are constant, and converts an alternating current whose magnitude and direction (positive current or negative current) change over time into a direct current whose magnitude is constant.

[0147] The rectifier circuit (310) may include a bridge diode. Specifically, the rectifier circuit (310) includes four diodes (D1, D2, D3, D4). The diodes (D1, D2, D3, D4) form diode pairs (D1 and D2, D3 and D4) in which two diodes are connected in series, and the two diode pairs (D1 and D2, D3 and D4) are connected in parallel with each other. The bridge diode converts an AC voltage whose polarity changes over time into a positive voltage whose polarity is constant, and converts an AC current whose direction changes over time into a positive current whose direction is constant.

[0148] Additionally, the rectifier circuit (310) includes a DC-coupled capacitor (C1). The DC-coupled capacitor (C1) converts a positive voltage whose magnitude varies over time into a DC voltage of a constant magnitude.

[0149] The inverter circuit (320a, 320b) includes a first inverter circuit (320a) and a second inverter circuit (320b). The first inverter circuit (320a) supplies a first resonant current to the load circuit (350) through a first output terminal (OUT1) according to the switching operation of the switching elements (DS11, DS12). The second inverter circuit (320b) supplies a second resonant current to the load circuit (350) through a second output terminal (OUT2) according to the switching operation of the switching elements (DS21, DS22).

[0150] The first current converter (330a) converts the first resonant current supplied from the first inverter circuit (320a) to the load circuit (350) into an intensity having a constant ratio. The converted first resonant current is provided to the pulse generation circuit. The second current converter (330b) converts the second resonant current supplied from the second inverter circuit (320a) to the load circuit (350) into an intensity having a constant ratio. The converted second resonant current is provided to the pulse generation circuit.

[0151] The load circuit (350) may include at least one resonant capacitor (CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8) connected in series or in parallel, at least one heating coil (WC1, WC2, WC3, WC4, WC5, WC6, WC7, WC8), and at least one relay (RL1, RL2, RL3, RL4, RL4, RL6).

[0152] Resonant capacitors (CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8) can be used to filter the DC component in the driving current. Heating coils (WC1, WC2, WC3, WC4, WC5, WC6, WC7, WC8) can be used to heat the cooking vessel using electromagnetic induction. Relays (RL1, RL2, RL3, RL4, RL4, RL6) can be used to selectively connect the heating coils (WC1, WC2, WC3, WC4, WC5, WC6, WC7, WC8) in series or parallel. Additionally, heating coils (WC1, WC2, WC3, WC4, WC5, WC6, WC7, WC8) and capacitors (CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8) can be used to determine the resonant frequency of the driving current.

[0153] The load circuit (350) may include a first resonant capacitor (CS1) that transmits a first resonant current supplied from a first inverter circuit (320a), a first heating coil (WC1) connected in series to the first resonant capacitor (CS1), a second heating coil (WC2) connected in series to the first heating coil (WC1), a second resonant capacitor (CS2) connected in series to the second heating coil (WC2), and a first relay (RL1) that switches the second resonant capacitor (CS2) and a ground voltage terminal.

[0154] In addition, the load circuit (350) may further include a third resonant capacitor (CS3) that transmits a second resonant current supplied from the second inverter circuit (320b), a third heating coil (WC3) connected in series to the third resonant capacitor (CS3), a fourth heating coil (WC4) connected in series to the third heating coil (WC3), a fourth resonant capacitor (CS4) connected in series to the fourth heating coil (WC4), and a second relay (RL2) that switches the fourth resonant capacitor (CS4) and a ground voltage terminal.

[0155] Additionally, the load circuit (350) may further include a third relay (RL3) that switches a node between the first heating coil (WC1) and the second heating coil (WC2) and a node between the third heating coil (WC3) and the fourth heating coil (WC4).

[0156] In addition, the load circuit (350) may further include a fifth resonant capacitor (CS5) that transmits a first resonant current supplied from the first inverter circuit (320a), a fifth heating coil (WC5) connected in series to the fifth resonant capacitor (CS5), a sixth heating coil (WC6) connected in series to the fifth heating coil (WC5), a sixth resonant capacitor (CS6) connected in series to the sixth heating coil (WC6), and a fourth relay (RL4) that switches the sixth resonant capacitor (CS6) and a ground voltage terminal.

[0157] In addition, the load circuit (350) may further include a seventh resonant capacitor (CS7) that transmits a second resonant current supplied from the second inverter circuit (320b), a seventh heating coil (WC7) connected in series to the seventh resonant capacitor (CS7), an eighth heating coil (WC8) connected in series to the seventh heating coil (WC7), an eighth resonant capacitor (CS8) connected in series to the eighth heating coil (WC7), and a fifth relay (RL5) that switches the eighth resonant capacitor (CS8) and a ground voltage terminal.

[0158] Additionally, the load circuit (350) may further include a sixth relay (RL6) that switches a node between the fifth heating coil (WC5) and the sixth heating coil (WC6) and a node between the seventh heating coil (WC7) and the eighth heating coil (WC8).

[0159] According to one embodiment of the present invention, a home appliance includes a load circuit including at least one heating coil, an inverter circuit including switching elements and supplying current to the load circuit according to switching operation of the switching elements, a current detection circuit detecting a resonant current output from the inverter circuit, a pulse generation circuit generating a pulse signal used to measure a phase difference between the resonant current and a switching voltage of the inverter circuit based on the resonant current, and a controller measuring the phase difference based on the pulse signal and measuring the output power of the load circuit based on the phase difference.

[0160] In one embodiment, the current sensing circuit may include a current converter that converts a resonant current output from the inverter circuit at a constant rate, and a stabilizing circuit that stabilizes and outputs the converted resonant current.

[0161] In one embodiment, the stabilizing circuit may include at least one resistor connected in parallel with the current transformer, one end connected to a ground voltage terminal and the other end connected to an output terminal, and a stabilizing capacitor connected in parallel with the at least one resistor, one end connected to the ground voltage terminal and the other end connected to the output terminal.

[0162] In one embodiment, the pulse generation circuit may include a first diode connected to an output terminal of a current sensing circuit, a first resistor connected in series with the first diode, a second diode having one end connected to a power voltage terminal and the other end connected to the first resistor, a second resistor having one end connected to the first resistor and the other end connected to a ground voltage terminal, a third resistor connected in series with the first resistor, a comparator having a first input terminal connected to the third resistor and a second input terminal connected to a reference voltage terminal, and a fourth resistor connected between an output terminal of the comparator and the first input terminal.

[0163] In one embodiment, the pulse generation circuit further includes first and second reference resistors connected in series between a power supply voltage terminal and a ground voltage terminal, and a reference capacitor connected between a node between the first and second reference resistors and the ground voltage terminal, wherein the node between the first and second reference resistors can be connected to the second input terminal of the comparator as the reference voltage terminal.

[0164] In one embodiment, the inverter circuit may include first and second switching elements connected in series between the high potential terminal and the low potential terminal, and first and second snubber capacitors connected in parallel to the first and second switching elements, respectively.

[0165] In one embodiment, the controller may define an internal PWM count start point as a phase margin start point, define a falling edge interrupt of a pulse signal as a phase margin end point, and compute a phase difference based on the phase margin start and end points.

[0166] In one embodiment, the controller can calculate the resonant voltage based on the input voltage and duty ratio of the inverter circuit.

[0167] In one embodiment, the controller can measure the output power of the load circuit based on the resonant voltage, resonant current, and phase difference.

[0168] In one embodiment, the controller can control the switching operation of the inverter circuit by adjusting at least one of a switching frequency and a duty ratio of the inverter circuit according to the output power of the load circuit.

[0169] In one embodiment, at least one heating coil may be formed as an integral multilayer PCB pattern assembly.

[0170] In one embodiment, the inverter circuit may include a first inverter circuit supplying a first resonant current to the load circuit, and a second inverter circuit supplying a second resonant current to the load circuit.

[0171] In one embodiment, the current sensing circuit can individually sense the first resonant current and the second resonant current output from the first inverter circuit and the second inverter circuit.

[0172] In one embodiment, the pulse generation circuit can generate a first pulse signal based on the first resonant current, the first pulse signal being used to measure a first phase difference between the first resonant current and a switching voltage of the first inverter circuit.

[0173] In one embodiment, the pulse generation circuit can generate a second pulse signal based on the second resonant current, which is used to measure a second phase difference between the second resonant current and the switching voltage of the second inverter circuit.

[0174] In one embodiment, the controller can individually measure the output power of the first inverter circuit and the second inverter circuit based on at least one of the first pulse signal and the second pulse signal.

[0175] While the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible. Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

Claims

1. A load circuit comprising at least one heating coil; An inverter circuit including switching elements and supplying current to the load circuit according to the switching operation of the switching elements; A current detection circuit that detects the resonant current output from the above inverter circuit; A pulse generation circuit that generates a pulse signal based on the resonant current and is used to measure the phase difference between the resonant current and the switching voltage of the inverter circuit; and A home appliance, comprising a controller that measures the phase difference based on the pulse signal and measures the output power of the load circuit based on the phase difference.

2. In paragraph 1, The above current sensing circuit A current converter that converts the resonant current output from the inverter circuit at a constant rate; and A home appliance comprising a stabilizing circuit that stabilizes and outputs the converted resonant current.

3. In paragraph 2, The above stabilization circuit At least one resistor connected in parallel to the current converter, one side of which is connected to a ground voltage terminal and the other side of which is connected to an output terminal; and A home appliance comprising a stabilizing capacitor connected in parallel with at least one resistor, one side of which is connected to the ground voltage terminal and the other side of which is connected to the output terminal.

4. In paragraph 1, The above pulse generation circuit A first diode connected to the output terminal of the above current sensing circuit; A first resistor connected in series with the first diode; A second diode having one end connected to the power supply voltage terminal and the other end connected to the first resistor; A second resistor having one end connected to the first resistor and the other end connected to the ground voltage terminal; A third resistor connected in series with the first resistor; A comparator having a first input terminal connected to the third resistor and a second input terminal connected to a reference voltage terminal; A home appliance comprising a fourth resistor connected between the output terminal of the comparator and the first input terminal.

5. In paragraph 4, The above pulse generation circuit First and second reference resistors connected in series between the power voltage terminal and the ground voltage terminal; and Further comprising a reference capacitor connected between the node between the first and second reference resistors and the ground voltage terminal, A home appliance, wherein the node between the first and second reference resistors is connected to the second input terminal of the comparator as the reference voltage terminal.

6. In paragraph 1, The above inverter circuit First and second switching elements connected in series between the high-potential terminal and the low-potential terminal; and A home appliance comprising first and second snubber capacitors connected in parallel to the first and second switching elements, respectively.

7. In paragraph 1, A home appliance in which the controller defines the start point of an internal PWM count as the start point of a phase margin, defines the falling edge interrupt of the pulse signal as the end point of the phase margin, and calculates the phase difference based on the start and end points of the phase margin.

8. In paragraph 7, A home appliance in which the controller calculates the resonant voltage based on the input voltage and duty ratio of the inverter circuit.

9. In paragraph 8, A home appliance, wherein the controller measures the output power of the load circuit based on the resonant voltage, the resonant current, and the phase difference.

10. In paragraph 1, A home appliance, wherein the controller controls the switching operation of the inverter circuit by adjusting at least one of the switching frequency and duty ratio of the inverter circuit according to the output power of the load circuit.

11. In paragraph 1, An appliance, wherein at least one heating coil is formed as an integral multilayer PCB pattern assembly.

12. In paragraph 1, The above inverter circuit A first inverter circuit supplying a first resonant current to the load circuit; and A home appliance comprising a second inverter circuit that supplies a second resonant current to the load circuit.

13. In paragraph 12, A home appliance, wherein the current detection circuit individually detects the first resonant current and the second resonant current output from the first inverter circuit and the second inverter circuit.

14. In paragraph 13, The pulse generation circuit generates a first pulse signal based on the first resonant current, which is used to measure a first phase difference between the first resonant current and the switching voltage of the first inverter circuit, A home appliance that generates a second pulse signal based on the second resonant current, the second pulse signal being used to measure a second phase difference between the second resonant current and the switching voltage of the second inverter circuit.

15. In paragraph 14, A home appliance, wherein the controller individually measures the output power of the first inverter circuit and the second inverter circuit based on at least one of the first pulse signal and the second pulse signal.

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