KR20200023729A - Induction heating apparatus and water purifier including the same - Google Patents

Abstract

The present invention relates to an induction heating device and a water purifier including the same. According to an embodiment of the present invention, the induction heating device comprises: a resonance unit resonated by a resonance voltage, and inducing an eddy current to an object to be heated by an electromagnetic induction effect by a magnetic field generated by the resonance voltage; an inverter unit for converting an input voltage into the resonance voltage by a switching operation, and supplying the same to the resonance unit; a noise detecting unit for detecting a quasi-peak value of electromagnetic interference (EMI) noise by the switching operation of the inverter unit; and a control unit for changing an output time point of a switching control signal for the switching operation of the inverter unit on the basis of the quasi-peak value of the EMI noise detected by the noise detecting unit. Accordingly, the EMI noise and switching loss can be reduced.

Description

Induction heating apparatus and water purifier including the same {INDUCTION HEATING APPARATUS AND WATER PURIFIER INCLUDING THE SAME}

The present invention relates to an induction heating apparatus and a water purifier having the same, and more particularly, to an induction heating apparatus and a water purifier having the same that can optimize the switching timing of the resonant inverter.

Generally, a water purifier is a device that filters and removes impurities from water to be supplied by physical and chemical methods.

Induction heating can be used for rapid hot water supply in direct type water purifiers. For example, the prior document (Korean Patent Laid-Open Publication No. 10-2005-0103723 (published date 2005.11.01.)) Describes a hot water supply device for a water purifier for heating purified water by an induction heating method.

Such an induction heating method supplies an electric current to a working coil to cause an electromagnetic induction phenomenon, thereby heating the heated object. Specifically, when an alternating current, particularly a high frequency alternating current, flows through the working coil, a magnetic field is generated in the working coil, and due to the electromagnetic induction effect by the magnetic field, an eddy current is induced in the heated object. Due to this eddy current, Joule heat is generated in the resistance of the object to be heated, and the heated object is heated.

On the other hand, the induction heating apparatus requires a switching element to generate resonance in the working coil and the resonant capacitor, and electromagnetic interference (EMI) noise and switching loss may be generated by the switching operation of the switching element.

Therefore, there is a need for a technique for reducing such electromagnetic interference (EMI) noise and switching loss.

An object of the present invention is to provide an induction heating apparatus and a water purifier having the same, which can change the switching timing of the inverter to reduce electromagnetic interference (EMI) noise and switching loss.

Induction heating apparatus according to an embodiment of the present invention for achieving the above object, and the resonance unit for resonating by the resonance voltage, and induces the eddy current in the heating object by the electromagnetic induction effect by the magnetic field generated by the resonance voltage and And converting an input voltage into the resonant voltage by a switching operation, and detecting a quasi-peak value of electromagnetic interference (EMI) noise by the switching operation of the inverter unit and the switching unit. And a control unit for changing an output time point of a switching control signal for switching operation of the inverter unit based on a quasi-peak value of electromagnetic interference (EMI) noise detected by the noise detection unit. .

Water purifier according to another embodiment of the present invention for achieving the above object, the resonator for resonating by the resonant voltage, inducing the eddy current to the heating object by the electromagnetic induction effect by the magnetic field generated by the resonant voltage, Converting an input voltage into the resonant voltage by a switching operation, and detecting a quasi-peak value of an electromagnetic interference (EMI) noise due to a switching operation of the inverter unit supplied to the resonator unit and a switching operation of the inverter unit. And a controller for changing an output time point of a switching control signal for switching operation of the inverter unit based on a quasi-peak value of electromagnetic interference (EMI) noise detected by the noise detector.

The induction heating apparatus according to the embodiment of the present invention adapts the output timing of the switching control signal for the switching operation of the inverter unit in response to the quasi-peak value of the electromagnetic interference (EMI) noise detected by the noise detector. As a result, the electromagnetic interference (EMI) noise can be efficiently reduced.

In addition, the induction heating apparatus does not directly detect the intersection of the input voltage and the resonant voltage, but detects electromagnetic interference (EMI) noise, in particular, differential-mode (DM) noise and uses it for feedback control. For example, the output timing of the switching control signal may be adaptively changed.

Further, the induction heating apparatus feedback-controls the quasi-peak value of the differential mode (DM) noise to change the output timing of the switching control signal. Therefore, the induction heating apparatus is more conventional than the voltage comparison method (for example, comparing the input voltage with the resonance voltage). View synchronization can be performed more accurately.

In addition, in the induction heating apparatus, the ringing phenomenon can be reduced when the timing at which the input voltage and the resonance voltage intersect and the switching timing are exactly matched.

In addition, the induction heating apparatus can efficiently reduce electromagnetic interference (EMI) noise without modifying or changing the design of the working coil.

On the other hand, distortion may occur at the switching timing of the induction heating apparatus due to the influence of the external environment, etc., but the induction heating apparatus of the present invention outputs the switching control signal in response to the quasi-peak value change of the differential mode (DM) noise. Since the viewpoint is adaptively changed, it is possible to minimize stress and efficiency reduction of the switching element due to distortion of the switching timing.

The water purifier according to another embodiment of the present invention adaptively outputs the switching time of the switching control signal for the switching operation of the inverter in response to the quasi-peak value of the electromagnetic interference (EMI) noise detected by the noise detector. In this way, electromagnetic interference (EMI) noise can be effectively reduced.

1 is a view showing the appearance of a water purifier according to an embodiment of the present invention.
FIG. 2 is an internal block diagram of the water purifier of FIG. 1.
3 is a diagram illustrating an internal circuit of the induction heating apparatus of FIG. 2.
4 is a diagram for explaining a switching control method of a conventional induction heating apparatus.
5 is a flowchart illustrating a method of operating an induction heating apparatus according to an embodiment of the present invention.
6 is a flowchart illustrating a method of operating an induction heating apparatus according to an embodiment of the present invention.
FIG. 7 is a diagram referred to the description of FIG. 5.
FIG. 8 is a diagram referred to the description of FIGS. 5 to 6.
9 is a diagram referred to the description of FIGS. 5 to 6.
FIG. 10 is a diagram referred to the description of FIGS. 5 to 6.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

The suffixes "module" and "unit" for components used in the following description are merely given in consideration of ease of preparation of the present specification, and do not impart any particular meaning or role by themselves. Therefore, the "module" and "unit" may be used interchangeably.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude, in advance, the existence or the possibility of adding numbers, steps, operations, components, parts, or combinations thereof.

1 is a view showing the appearance of a water purifier according to an embodiment of the present invention.

Referring to the drawings, the water purifier 100 according to the embodiment of the present invention may include a case 110, the water intake unit 120, the tray 130 and the input unit 140.

The case 110 forms the exterior of the water purifier 100. Most parts for filtering raw water are installed inside the case 110. In addition, the induction heating apparatus 260, components for supplying cold water, and the like may also be disposed in the case 110. Case 110 wraps the parts to protect them. The case 110 may be formed of a single part, but may be formed by a combination of several parts.

The tray 130 is disposed to face the water intake part 120 in the vertical direction. The tray 130 supports a container or the like for containing purified water provided through the water intake unit 120. In addition, the tray 130 may be formed to accommodate the remaining water falling from the water intake unit 120.

Since the tray 130 must receive the remaining water falling from the intake unit 120, the tray 130 may also be implemented to rotate together with the intake unit 120. In addition, the input unit 140 may also be implemented to rotate in the same direction as the intake unit 120 and the tray 130.

The input unit 140 may include input means such as a button or a touch screen to receive a user's control command. The input means may include all of the touch input, the physical pressing, or the like selectively.

At least a portion of the water intake unit 120 may be formed to protrude from the water purifier 100 for ease of use.

In addition, as shown in (a) and (b) of Figure 1, the water intake unit 120 may be configured to be rotatable according to the user's operation. Alternatively, unlike (a) and (b) of FIG. 1, the intake part 120 may be configured to be movable up and down.

In some cases, the water intake unit 120 may be provided in plurality, and configured to supply cold water and hot water, respectively.

On the other hand, the water intake unit 120 may be connected to the drain pipe to provide the user with at least one of hot water, cold water and purified water.

In response to a user input through the input unit 140, the water intake unit 120 may be supplied with hot water heated by the induction heating apparatus 260.

FIG. 2 is an internal block diagram of the water purifier of FIG. 1.

Referring to the drawings, the water purifier 100 according to the embodiment of the present invention, the input unit 140, memory 210, sensor unit 220, output unit 230, water supply valve 240, hot water discharged The valve 250, the heating unit 260, the hot water tank 265, and the cold water outlet valve 270 may be included.

The input unit 140 may receive a user control command. The input unit 140 may transmit a user control command to the control unit 280. For example, the input unit 140 may receive a hot water discharge command and transmit it to the controller 280. The controller 280 may control the heating unit 260, the water supply valve 240, and the like to supply hot water in response to a user's hot water discharge command.

The output unit 230 may be provided with an output unit so as to provide the user with the state information of the water purifier 100 visually. For example, the output unit 230 may be provided with output means such as a display and a speaker. In some cases, the display may be configured as a touch screen and used as an input / output means.

The controller 280 may control the water supply valve 240, the hot water discharge valve 250, the heating unit 260, and the cold water discharge valve 270.

The controller 280 may stop driving of the heating unit 260 and drive a cooling device (not shown) in response to a cold water discharge command of the user. In addition, the controller 280 may open the cold water outlet valve 270 and the water supply valve 240.

When the user inputs the cold water discharge command by inputting the input unit 140, the internal water of the cold water tank (not shown) is discharged to the outside through the cold water discharge flow path (not shown), and the water of the reservoir tank (not shown) is cold water As the water is discharged from the tank is moved to the cold water tank, the water in the raw water supply flow path (not shown) may be purified while passing through the filter may be filled into the reservoir through the storage tank inlet flow path (not shown).

The controller 280 may drive the heating unit 260 in response to a user's hot water discharge command, and may open the hot water discharge valve 250 and the water supply valve 240.

The controller 280 may drive or stop the cooling device in the hot water discharge mode, and may close the cold water discharge valve 270.

The sensor unit 220 may be disposed in a flow path through which hot water, cold water, or purified water flows, and detect a flow rate, temperature, and the like of hot water, cold water, or purified water. In addition, the sensor unit 220 may be disposed in the reservoir to sense the flow rate, temperature, and the like of the reservoir. The sensor unit 220 may transmit water temperature, flow rate information, and the like to the controller 280.

On the other hand, the controller 280 may control the output of the heating unit 260 for heating the hot water tank 265 based on the user control command, and may control the temperature of the hot water discharged.

In this case, the hot water tank 265 may be a flow rate tank in which purified water passing through a filter installed in the water purifier 100 is stored, heated with hot water, and then withdrawn. In addition, the heating unit 260 may be a heating device for heating the hot water stored in the hot water tank 265.

On the other hand, since the water purifier 100 of the present invention heats the hot water tank 265 which is the heating target body by the resonance induction method, the heating unit 260 of FIG. 2 may be the induction heating apparatus 260. Hereinafter, it demonstrates on the assumption that the heating part 260 is the induction heating apparatus 260.

The induction heating apparatus 260 may be an induction heater (IH) that generates Joule heat through an induction current generated by a magnetic field when the high frequency AC power is applied, thereby heating the contacted metal body.

In this case, the metal body in contact with the induction heating apparatus 260 may be a hot water tank 265.

That is, in the water purifier 100, the hot water tank 265 is in contact with the heating part 260, and as the heating part 260 generates heat in the hot water tank 265 according to the alternating current power applied thereto, the hot water tank 265. 265 may be heated. Accordingly, the purified water may be heated to a high temperature for a short time passing through the induction heating apparatus 260 and discharged.

Meanwhile, when the heating unit 260 is the induction heating device 260, the memory 210 and the control unit 280 of FIG. 2 may have a configuration included in the induction heating device 260.

The memory 210 may store overall data for controlling the water purifier 100. In particular, the memory 210 may store information about a time point at which the input voltage and the resonance voltage intersect according to the level of the input voltage and the level of the resonance voltage. In addition, the memory 210 may store information about a delay time of the switching element.

Meanwhile, the water purifier 100 of the present invention is not limited to the configuration of FIG. 2, and the configuration may be added or changed according to an embodiment.

3 is a diagram illustrating an internal circuit of the induction heating apparatus of FIG. 2.

Referring to the drawings, the induction heating apparatus 260 according to an embodiment of the present invention, the resonator 310, the inverter 330, the filter 350, the noise detector 370, the output current detector ( A).

The resonator 310 may resonate by the resonant voltage Vds and induce an eddy current in the heated object by an electromagnetic induction effect by the magnetic field generated by the resonant voltage Vds.

Specifically, the resonator 310 is connected in parallel to the working coil Lw and the working coil Lw that induces heating of the heated object by using the resonance voltage to form the resonant circuit with the working coil Lw. It may include a resonant capacitor (Cp).

In addition, the resonator 310 may further include a coil resistor Rw connected in parallel to the working coil Lw and the resonant capacitor Cp.

In this case, the coil resistance Rw may be a resistance value reflecting the resistance component of the resonator 310 itself, the resistance component of the working coil Lw, and the resistance component caused by the counter electromotive force generated in the working coil Lw. .

When an alternating current, particularly a high frequency alternating current, is applied to the working coil Lw by the resonance voltage Vds, an LC resonance circuit by the working coil Lw and the resonance capacitor Cw, or the working coil Lw. ), A resonant capacitor Cw, and an RLC resonant circuit may be formed by the coil resistor Rw.

Due to this resonance, a magnetic field is generated in the working coil Lw, and due to the electromagnetic induction effect by the magnetic field, an eddy current may be induced in the heated object.

In addition, Joule heat is generated in the resistance component of the object to be heated by the eddy current, so that the object to be heated can be heated.

That is, the resonator 310 may heat the heated object using the resonant voltage Vds. On the other hand, when the induction heating apparatus 260 of the present invention is disposed in the water purifier 100, the heated object may be a hot water tank 255.

The inverter unit 330 may convert the input voltage Vi into the resonance voltage Vds by the switching operation, and supply the input voltage Vi to the resonance unit 310.

The inverter unit 330 may include a single switching element S1 and an antiparallel diode element D2 connected to the switching element S1.

One end of the switching element S1 may be connected to the working coil Lw and the resonant capacitor Cw, and the other end thereof may be connected to the output current detector A. FIG.

The switching element S1 can generate the resonance voltage Vds by a switching operation. The resonance voltage Vds may occur during the turn off period of the switching element S1.

The resonance voltage Vds may be applied to the resonator 310 by the switching operation of the switching element S1 (Vo = Vds). In addition, AC power ilp and icp by the resonance voltage Vds may be supplied to the resonator 310. In this case, the coil current ilp supplied to the working coil Lw may be a high frequency induction current.

The switching element S1 may be a high frequency semiconductor element. For example, the switching element S1 includes a bipolar junction transistor (BJT), a metal oxide semiconductor field effect transistor (MOST), an insulated gate bipolar transistor (IGBT). May be). When the switching element S1 is an IGBT, high-speed high-speed switching may be possible.

The controller 280 may output a switching control signal Sic according to a pulse width modulation (PWM) scheme for controlling the inverter unit 330. For example, when the switching element S1 is an IGBT, the controller 280 may output a gate driving signal according to a pulse width modulation (PWM) method.

The switching element S1 in the inverter unit 330 may perform a switching operation based on the switching control signal Sic. By the switching operation of the switching element S1, the LC resonant circuit or the RLC resonant circuit repeats the energy charging and discharging by the time constant so that the resonator 310 can inductively heat the heated object.

The controller 280 may variably control the output of the induction heating apparatus 260 based on the user control command and the output current id detected by the output current detector A. FIG.

For example, the controller 280 may include a switching control signal for varying the frequency or phase of the AC power ilp and icp supplied to the resonator 310 based on a user control command and an output current id. Sic) may be generated and the switching control signal Sic may be output to the inverter unit 330.

The noise detector 370 may detect a quasi-peak value of electromagnetic interference (EMI) noise due to the switching operation of the inverter unit 330. To this end, the noise detector 370 may include a quasi-peak detector.

The noise detector 370 may include a first resistor element R1 and a first capacitor element C1 connected in parallel to the input terminal of the controller 280. The first resistance element R1 and the first capacitor element C1, which are connected in parallel, can be used as an integrator.

 The noise detector 370 may further include a diode element D1 connected in series to the filter unit 350 and a second resistor element R2 connected in series with the diode element D1. The second resistance element R2 may be connected to the integrator. In this case, the diode element D1 may be a high frequency diode, and the second resistor element R2 may prevent the high frequency current from being applied to the integrator.

The noise detector 370 may integrate quasi-peak values by integrating electromagnetic interference (EMI) noise with time based on a predetermined time constant value. In this case, the time constant may be determined by the first resistor element R1 and the first capacitor element C1.

The controller 280 may calculate a quasi-peak value of electromagnetic interference (EMI) noise at a specific time point based on the detection information of the noise detector 370. For example, the controller 280 may calculate that a quasi-peak value is larger as a pulse repetition frequency is larger. In addition, the control unit 280 may calculate that the higher the peak value of the electromagnetic interference (EMI) noise, the larger the quasi-peak value.

The controller 280 may change an output time point of the switching control signal Sic based on a quasi-peak value of electromagnetic interference (EMI) noise detected by the noise detector 370.

As the induction heating apparatus 260 of the present invention uses quasi-peak values, not peak values of electromagnetic interference (EMI) noise, it is not a temporary change of electromagnetic interference (EMI) noise. The output time of the switching control signal Sic may be changed using the amount of change over time.

As a result, the number of changes at the switching control point is reduced, thereby improving device durability, improving control accuracy, and ensuring control stability.

Meanwhile, the induction heating apparatus 260 according to the embodiment of the present invention may further include a filter unit 350 in front of the noise detector 370.

The filter unit 350 is connected between the output current detector A and the noise detector 370 to filter DC components of electromagnetic interference (EMI) noise.

The filter unit 350 may include a high pass filter (HPF). For example, the filter unit 350 may include a second capacitor element C2, one end of which is connected to the output current detection unit A, and the other end of which is connected to the diode element D1, and the second capacitor element C2. The third resistor device R3 may be connected between the node between the first diode device D1 and the ground terminal.

The output current detection unit A is connected to the output terminal of the inverter unit 330 and can detect the output current by the switching operation of the inverter unit 330.

The output current detector A may include a shunt resistor Rs. The shunt resistor Rs may be connected between the switching element S1 and the ground terminal.

The controller 280 may generate the switching control signal Sic based on the output current detected by the output current detector A. FIG. For example, the controller 280 may variably generate the duty of the switching control signal Sic corresponding to the target output of the induction heating apparatus 260 based on the output current.

Meanwhile, the induction heating apparatus 260 according to the embodiment of the present invention may further include a converter (not shown) for converting commercial AC power into DC power. In this case, the converter (not shown) may be disposed in front of the resonator 310.

The converter (not shown) includes a diode element and a switching element, and may output a DC power source converted according to the operation of the switching element and the rectifying characteristics of the diode element. Alternatively, the converter (not shown) may be formed of a diode element instead of a switching element.

On the other hand, the induction heating apparatus 260 according to the embodiment of the present invention may further include a voltage detector (not shown) for detecting the input voltage Vin and the resonance voltage (Vds), the control unit 280, Based on the detection information of the voltage detector, an intersection point of the input voltage Vin and the resonance voltage Vds may be calculated.

4 is a diagram for explaining a switching control method of a conventional induction heating apparatus.

In FIG. 4, 410 represents a resonance voltage Vds, 430 represents an input voltage Vin, 450 represents a hardware (H / W) trigger, and 470 represents a PWM pulse.

Referring to the drawings, in the induction heating apparatus 260 having a single switching element, when the switching element S1 performs a high frequency switching operation, the voltage and current stress of the switching element S1 increase and Electromagnetic interference (EMI) noise may occur.

In order to reduce such electromagnetic interference (EMI) noise, the induction heating apparatus 260 is a soft switching technique using the resonance characteristics of the resonator 310 when the input voltage Vi and the resonance voltage Vds cross each other. Zero voltage switching (ZVS) can be performed.

However, as shown in FIG. 4, due to the sampling time and other parasitic components of the switching element S1, a delay time Tdelay due to voltage transition may occur in the on-off switching period of the switching element S1.

The delay time Tdelay may amplify the electromagnetic interference (EMI) noise of the switching element S1 and may cause a ringing phenomenon in the induction heating apparatus 260.

In order to solve this problem, the induction heating apparatus 260 of the present invention, based on the quasi-peak value of the electromagnetic interference (EMI) noise of the switching element (S1), the switching operation of the switching element (S1) An output time point of the switching control signal Sic may be changed.

The change of the output time point of the switching control signal Sic will be described in more detail with reference to FIG. 5.

5 to 6 are flowcharts showing an operating method of the induction heating apparatus according to the embodiment of the present invention, and FIG. 7 is a diagram referred to the description of FIG. 5.

First, in FIG. 5, the controller 280 may calculate the intersection point of the input voltage Vin and the resonance voltage Vds as a basic output time point of the switching control signal Sic (S510).

An intersection point between the input voltage Vin and the resonance voltage Vds may be calculated by the controller 280 based on detection information of a voltage detector (not shown). Alternatively, the intersection point of the input voltage Vin and the resonance voltage Vds may be determined by experiment based on the size of a commercial AC power source, the input terminal voltage of the resonator 310, the time constant of the resonator 310, and the like. .

On the other hand, when the induction heating apparatus 260 performs the switching operation by the soft switching technique at the basic output time point of the switching control signal Sic, as shown in FIG. 4, the sampling time of the switching element S1, and the like. Due to the parasitic component, a delay time Tdelay due to voltage transition may occur in the on-off switching period of the switching element S1.

Such a delay time Tdelay may amplify the electromagnetic interference (EMI) noise of the switching element S1 and may cause a ringing phenomenon in the induction heating apparatus 260.

In order to solve this problem, the induction heating apparatus 260 of the present invention may output the switching control signal Sic in consideration of the delay time Tdelay time.

That is, the controller 280 may output the switching control signal Sic at the first compensation time point, which is a time point preceding the first time point from the basic output time point (S520).

At this time, the size of the advanced first time point may be equal to the size of the delay time Tdelay. In addition, the delay time Tdelay may be determined by experiment in consideration of the magnitude of the input voltage Vin, the time constant of the resonance voltage Vds, the sampling time of the switching element S1, other parasitic components, and the like. The memory 210 may store a delay time Tdelay determined by an experiment.

As the switching control signal Sic is output at the first compensation time point, the delay time Tdelay of the switching element S1 may be lost or reduced.

On the other hand, since the first compensation time point is determined by an experiment and does not reflect the change in the ambient environment, even when the switching control signal Sic is output at the first compensation time point, the ambient environment of the induction heating apparatus 260 is used. Depending on the change (eg, weather, temperature, humidity, etc.), distortion of the parameter may occur. In addition, due to the distortion of the parameter, the level of electromagnetic interference (EMI) noise may be increased.

In order to solve this problem, the controller 280 may adaptively change the output time of the switching control signal Sic based on the quasi-peak value of the noise detected by the noise detector 370. have

In detail, the controller 280 may output the switching control signal (Sic) at a second compensation time point that is a point ahead of the first compensation time point by a second time point (S530). At this time, the size of the second time point, which is advanced, is set smaller than that of the first time point, so that a sudden change in the electromagnetic interference (EMI) noise can be prevented.

The control unit 280 may include a quasi-peak value of the first electromagnetic interference (EMI) noise at the first compensation point and a quasi-peak value of the second electromagnetic interference (EMI) noise at the second compensation point. -peak), the output time of the switching control signal (Sic) can be changed (S540).

The quasi-peak value of the electromagnetic interference (EMI) noise may be a value obtained by integrating the electromagnetic interference (EMI) noise with time based on a predetermined time constant. For example, the greater the frequency of occurrence of pulses of electromagnetic interference (EMI) noise in a predetermined period, the greater the quasi-peak value of the electromagnetic interference (EMI) noise. As another example, the greater the peak value of the EMI noise, the greater the quasi-peak value of the EMI noise.

The controller 280 outputs the switching control signal Sic at the second compensation time point, and a quasi-peak value of the noise at the second compensation time point is a quasi-peak value at the first compensation time point. If the value is larger than the quasi-peak value, the switching control signal Sic may be output at a third compensation time delayed by a third time point (S550).

Alternatively, the controller 280 outputs the switching control signal Sic at the second compensation time point, and the quasi-peak value of the noise at the second compensation time point is the noise at the first compensation time point. If smaller than the quasi-peak value, the switching control signal Sic may be output at a fourth compensation time point, which is a time point preceding the fourth time point (S560).

Based on the noise of the induction heating apparatus 260, as the output time point of the switching control signal Sic is changed, the parameter distortion of the induction heating apparatus 260 may be reduced.

On the other hand, as the induction heating apparatus 260 uses quasi-peak values, not peak values of EMI noise, it is not a temporary change of EMI noise. By changing the output time of the switching control signal (Sic) by using the amount of change over time, the control stability can be improved.

Next, in FIG. 6, the controller 280 may change the output time of the switching control signal Sic based on the quasi-peak value of the electromagnetic interference (EMI) noise as shown in FIG. 5 ( S610).

The controller 280 may change an output time point of the switching control signal Sic until a quasi-peak value of the noise detected by the noise detector 370 is within a predetermined range (S630). .

For example, when the quasi-peak value of the noise detected by the noise detector 370 is not included within a preset range at the third compensation time point, the controller 280 may perform the third compensation time point. The quasi-peak value of the EMI noise and the quasi-peak value of the EMI noise at the second compensation time can be compared.

The control unit 280, the quasi-peak value of the electromagnetic interference (EMI) noise at the third compensation point, the quasi-peak value of the electromagnetic interference (EMI) noise at the second compensation point If larger, the output time of the switching control signal Sic may be output at the fifth compensation time, which is a time delayed by the fifth time.

Alternatively, the controller 280 may include a quasi-peak value of the electromagnetic interference (EMI) noise at the third compensation point, and a quasi-peak of the electromagnetic interference (EMI) noise at the second compensation point. When the value is smaller than), the output time point of the switching control signal Sic may be output at the sixth compensation time point, which is a time point preceding the sixth time point.

The controller 280 advances or delays the output time of the switching control signal Sic, as in the above example, until the quasi-peak value of the electromagnetic interference (EMI) noise is included in the preset range. You can.

In this case, the preset range may be appropriately set in consideration of the EMC international standard. In addition, the preset range may be stored in the memory 210 in advance.

Meanwhile, when the quasi-peak value of the noise detected by the noise detector 370 is included within the preset range, the controller 280 no longer switches the switching control signal Sic at the third compensation time. Does not change the output time.

As described above, the induction heating apparatus 260 of the present invention is based on a quasi-peak value of noise in a state where the output time of the switching control signal Sic is changed to the second compensation time. The output time point of the switching control signal Sic can be adaptively changed in accordance with the change of the surrounding environment. As a result, electromagnetic interference (EMI) noise and ringing of the induction heating apparatus 260 may be reduced.

8-10 is a figure referred to the description of FIGS. 5-6.

More specifically, FIGS. 8 to 9 are views illustrating a change in the output time point of the switching control signal Sic according to an embodiment of the present invention, and FIG. 10 is a change in the output time point of the switching control signal Sic. It is a figure for explaining the change in the ringing phenomenon according to. 8 to 9, 810 and 910 represent the magnitudes of the input voltage Vi according to the phases, respectively.

Referring to the drawings, first, in FIG. 8, the controller 280 may output the switching control signal Sic to the first compensation time point Tp1, which is a time point earlier than the first time point from the basic output time point. In this case, the magnitude of the first time point may be determined by experiment in consideration of the magnitude of the input voltage Vin, the time constant of the resonance voltage Vds, the sampling time of the switching element S1, and other parasitic components. .

The controller 280 may include a second compensation time point Tp2 that is a point ahead of the first compensation time point Tp1 by a second time point t2 in order to reflect a parameter change of the induction heating apparatus 260 according to a change in the surrounding environment. The switching control signal Sic may be output to the.

The controller 280 may set the size of the second viewpoint t2 to be smaller than the first viewpoint. Accordingly, a sudden change in the electromagnetic interference (EMI) noise due to the change of the output time of the switching control signal (Sic) can be prevented.

The control unit 280 compensates for the first compensation of the quasi-peak value of the noise at the second compensation time point Tp2 with the switching control signal Sic being output at the second compensation time point Tp2. When the noise is greater than the quasi-peak value of the noise at the time point Tp1, the switching control signal Sic may be output to the third compensation time point Tp3 delayed by the third time point t3.

The controller 280 may set the size of the second time point t2 to be smaller than the size of the third time point t3. That is, the controller 280 adjusts the size of the forward point and the delayed point so that the output point of the switching control signal Sic gradually moves from the first compensation point Tp1 to the optimum point op. You can do that.

Meanwhile, the optimum point op may mean an output time point of the switching control signal Sic when a quasi-peak value of noise is included within a preset range.

The controller 280 may calculate whether or not a quasi-peak value of the noise detected by the noise detector 370 is within a preset range at the third compensation time point Tp3.

If the quasi-peak value of the noise is not included within the preset range at the third compensation point Tp3, the controller 280 may emit the electromagnetic interference EMI at the third compensation point Tp3. A quasi-peak value of the noise and a quasi-peak value of the EMI noise at the second compensation time point Tp2 may be compared.

The controller 280 indicates that the quasi-peak value of the electromagnetic interference EMI noise at the third compensation point Tp3 is the quasi-peak of the electromagnetic interference EMI noise at the second compensation point Tp2. If greater than the quasi-peak value, the output time of the switching control signal Sic may be output to the fifth compensation time Tpa, which is a time delayed by the fifth time ta.

In addition, the controller 280 outputs the switching control signal Sic at the fifth compensation point Tpa, and the quasi-peak value of the noise at the fifth compensation point Tpa is equal to the first. When the noise is greater than the quasi-peak value of the noise at the third compensation time point Tp3, the output time point of the switching control signal Sic may be output to the seventh compensation time point Tpb which is an optimum point op. .

On the other hand, the control unit 280 can control the output time of the switching control signal (Sic) more precisely by setting the sizes of the delay time (t3, ta, tb) gradually (t3> ta> tb).

Next, in FIG. 9, as shown in FIG. 8, the controller 280 may output the switching control signal Sic to the first compensation time point Tp1, which is a time point preceding the first time point from the basic output time point.

In addition, as shown in FIG. 8, the controller 280 is a point in time ahead of the first compensation point Tp1 by a second point in time t2 in order to reflect a parameter change of the induction heating apparatus 260 according to the change in the surrounding environment. The switching control signal Sic may be output at the second compensation time point Tp2.

The control unit 280 compensates for the first compensation of the quasi-peak value of the noise at the second compensation time point Tp2 with the switching control signal Sic being output at the second compensation time point Tp2. When the noise is smaller than the quasi-peak value of the noise at the time point Tp1, the switching control signal Sic may be output to the fourth compensation time point Tp4, which is a time point that is advanced by the fourth time point t4.

The controller 280 indicates that the quasi-peak value of the electromagnetic interference EMI noise at the fourth compensation point Tp4 is the quasi-peak of the electromagnetic interference EMI noise at the second compensation point Tp2. When the value is smaller than the quasi-peak value, the output time point of the switching control signal Sic may be output to the sixth compensation time point Tpc which is a time point forwarded by the sixth time point tc.

In addition, the controller 280 outputs the switching control signal Sic at the sixth compensation point Tpc, and the quasi-peak value of the noise at the sixth compensation point Tpc is set to the first value. When the noise is greater than the quasi-peak value of the noise at the fourth compensation time point Tp4, the output time point of the switching control signal Sic may be output to the eighth compensation time point Tpd which is an optimum point op. .

Meanwhile, the controller 280 may control the output time of the switching control signal Sic more precisely by setting the sizes of the advanced time points t4, tc, and td gradually smaller (t4> tc>). td).

As described above, even when the switching control signal Sic is output at the first compensation time point Tp1, a distortion of the parameter may occur according to a change in the surrounding environment of the induction heating apparatus 260. In addition, the distortion of such a parameter may cause an increase in electromagnetic interference (EMI) noise and a ringing phenomenon.

The induction heating apparatus 260 of the present invention solves this problem by pulling or delaying the output time of the switching control signal Sic based on the quasi-peak value of the electromagnetic interference (EMI) noise. Can be.

That is, the induction heating apparatus 260 of the present invention outputs a switching control signal Sic for switching operation of the inverter unit 330 based on a quasi-peak value of electromagnetic interference (EMI) noise. As the viewpoint is changed, it can be seen that the ringing phenomenon, as in FIG. 10A, is reduced as in FIG. 10B.

The accompanying drawings are only for easily understanding the embodiments disclosed in the present specification, and the technical idea disclosed in the present specification is not limited by the accompanying drawings, and all modifications and equivalents included in the spirit and scope of the present invention are provided. It should be understood to include water or substitutes.

Likewise, although the operations are depicted in the drawings in a specific order, it should not be understood that such operations must be performed in the specific order or sequential order shown in order to obtain desirable results, or that all illustrated operations must be performed. . In certain cases, multitasking and parallel processing may be advantageous.

In addition, while the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

100: water purifier
210: memory
260: induction heating device
265: hot water tank
280: control unit
310: resonator
330: inverter unit
350: filter unit
370: noise detector

Claims (12)

A resonator configured to resonate by a resonant voltage and induce an eddy current to the heated object by an electromagnetic induction effect of the magnetic field generated by the resonant voltage;
An inverter unit converting an input voltage into the resonance voltage by a switching operation and supplying the resonance voltage to the resonance unit;
A noise detector for detecting a quasi-peak value of electromagnetic interference (EMI) noise by the switching operation of the inverter unit; And
And a controller configured to change an output time point of a switching control signal for switching operation of the inverter unit based on a quasi-peak value of the electromagnetic interference (EMI) noise detected by the noise detector. Induction heating device.
The method of claim 1,
The control unit,
Inductive heating, characterized in that for calculating a basic output time point that is the time when the input voltage and the resonant voltage intersects, and outputs the switching control signal at a first compensation time point that is a time point earlier than the first output time point. Device.
The method of claim 2,
The control unit,
The switching control signal is output at a second compensation time point that is a point ahead of the first compensation time point by a second time point, and has a quasi-peak value of EMI noise at the first compensation time point and the second compensation time point. And an output time point of the switching control signal based on a quasi-peak value of electromagnetic interference (EMI) noise at the time point.
The method of claim 3,
The control unit,
The switching control signal when the quasi-peak value of the noise at the second compensation point is greater than the quasi-peak value of the noise at the first compensation point in the state where the switching control signal is output at the second compensation point The signal is output at a third compensation time point delayed by a third time point.
The method of claim 4, wherein
The control unit,
The switching control signal when the quasi-peak value of the noise at the second compensation time point is smaller than the quasi-peak value of the noise at the first compensation time point while the switching control signal is output at the second compensation time point. And a signal is output at a fourth compensation time point, which is a time point preceding the fourth time point.
The method of claim 5,
The control unit
And an output time point of the switching control signal until a quasi-peak value of electromagnetic interference (EMI) noise falls within a predetermined range.
The method of claim 1,
The resonator unit,
And a working coil which induces heating to the heated object by using the resonance voltage, and a resonance capacitor which is connected in parallel with the working coil to form the working coil and the resonance circuit.
The method of claim 7, wherein
The inverter unit,
And a switching element connected to the working coil and the resonant capacitor to generate the resonance voltage through a switching operation, and an antiparallel diode element connected to the switching element.
The method of claim 1,
An output current detection unit connected to the inverter unit and detecting an output current generated by a switching operation of the inverter unit;
The control unit,
And the switching control signal is generated based on the output current detected by the output current detector.
The method of claim 9,
And a filter unit connected between the output current detection unit and the noise detection unit to filter a direct current component of the electromagnetic interference (EMI) noise.
The method of claim 10,
The noise detector,
A quasi-peak of the electromagnetic interference (EMI) noise, including a first resistor element and a first capacitor element connected in parallel to an input terminal of the controller, and based on time constant values of the first resistor element and the first capacitor element; Induction heating apparatus, characterized in that for outputting a value to the control unit.
The water purifier provided with the induction heating apparatus of Claims 1-11.

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