KR20210006809A - Induction heating device having improved temperature sensing mechanism - Google Patents

Abstract

The present invention relates to an induction heating device having an improved temperature sensing mechanism. In addition, according to an embodiment of the present invention, the induction heating device includes: a power supply unit which outputs AC power; a rectifying module which rectifies AC power outputted from a power supply into DC power; a working coil receiving rectified DC power from a rectifier module; a switch unit having one end connected to the working coil; a shunt resistor connected to the other end of the switch; and a control unit which turns on the switch unit every preset period so that the DC power rectified by the rectifier module is applied to the shunt resistor through the working coil, detects the voltage of the DC power applied to the shunt resistor, determines whether or not the temperature of the working coil is within a safe temperature range based on a detection result, and generates a control signal for controlling the output of the working coil based on the determination result. The present invention provides the induction heating device with improved temperature sensing accuracy.

Description

Induction heating device with improved temperature sensing mechanism {INDUCTION HEATING DEVICE HAVING IMPROVED TEMPERATURE SENSING MECHANISM}

The present invention relates to an induction heating device with an improved temperature sensing mechanism.

Various types of cooking utensils are used to heat food at home or in a restaurant. Conventionally, gas ranges using gas as fuel have been widely used and widely used, but recently, devices for heating an object to be heated, such as a pan, by using electricity without using gas have been popularized.

Methods of heating an object to be heated using electricity are largely divided into resistance heating methods and induction heating methods. The electrical resistance method is a method of heating an object to be heated by transferring heat generated when current is passed through a metal resistance wire or a non-metallic heating element such as silicon carbide to the object to be heated through radiation or conduction. In addition, the induction heating method generates an eddy current in an object to be heated (for example, a cooking vessel) made of metal by using a magnetic field generated around the coil when high-frequency power of a predetermined size is applied to the coil. This is a method that allows the heating element itself to be heated.

Among them, an induction heating apparatus to which an induction heating method is applied generally includes a working coil in a corresponding region for heating each of a plurality of objects to be heated (eg, a cooking vessel).

Here, referring to FIGS. 1 and 2, conventional induction heating devices are shown, and a temperature sensing method of conventional induction heating devices will be described with reference to these.

1 and 2 are views illustrating a temperature sensor provided in a conventional induction heating apparatus.

For reference, FIG. 1 is a view shown in Korean Patent Publication No. 10-0661226, and FIG. 2 is a view shown in Korean Patent Publication No. 10-2012-0011186, respectively, used in FIGS. 1 and 2 Reference numerals are limited to each of FIGS. 1 and 2 and applied.

First, referring to FIG. 1, in the case of a conventional induction heating device, a heater unit including an electrothermal heating unit 100 and an induction heating heating unit 110 and a temperature sensor 120 installed in the heater unit are included.

Here, the temperature sensor 120 is disposed in the center of the induction heating coil 111 provided in the induction heating heating unit 110 to sense the temperature of the heater unit.

Next, referring to FIG. 2, in the case of a conventional induction heating apparatus, a plurality of working coils 20 and a plurality of temperature sensors 30 sensing the temperature of the working coil 20 or an object to be heated are included.

Here, the plurality of temperature sensors 30 are provided between the plurality of working coils 20 to sense the temperature of the surrounding working coils 20.

As described above, in the conventional induction heating apparatus, the temperature sensor is installed around the coil, but is close to the upper plate (that is, it means a countertop made of a flat plate so that the object to be heated can be disposed on the upper surface, and is generally made of glass). To be placed.

However, there is a problem that the temperature detection accuracy of the temperature sensor is deteriorated due to the distance tolerance between the upper plate and the temperature sensor, and since a wire harness is required to install the temperature sensor, manufacturing cost increases and manufacturing workability ( That is, there is also a problem that the easiness of the manufacturing operation) decreases.

An object of the present invention is to provide an induction heating apparatus with improved temperature sensing accuracy.

It is also an object of the present invention to provide an induction heating device with improved manufacturing workability.

The object of the present invention is not limited to the above-mentioned object, and other objects and advantages of the present invention not mentioned can be understood by the following description, and will be more clearly understood by the examples of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by the means shown in the claims and combinations thereof.

The induction heating apparatus according to the present invention can determine the temperature of the working coil without a temperature sensor by implementing a series-connected current path through which the DC power rectified in the rectifying module is applied to the shunt resistor through the working coil, Through this, temperature sensing accuracy can be improved.

Specifically, the induction heating device according to the present invention includes a rectifying module for rectifying AC power output from a power supply unit to DC power, a working coil receiving rectified DC power from the rectifying module, a switch unit having one end connected to the working coil, and a switch unit. The shunt resistor connected to the other end and the switch unit are turned on at each preset period so that the DC power rectified in the rectifier module is applied to the shunt resistor through the working coil, and the voltage of the DC power applied to the shunt resistor is sensed, based on the detection result. It is possible to improve the accuracy of temperature detection by including a control unit that determines whether the temperature of the working coil is within a safe temperature range.

In addition, the induction heating apparatus according to the present invention can determine the temperature of the working coil without a temperature sensor by deriving the temperature of the working coil based on the resistance value of the working coil, thereby improving manufacturing workability.

Specifically, the induction heating device according to the present invention detects the magnitude of the voltage distributed to the shunt resistor, calculates the magnitude of the voltage distributed to the working coil and the resistance value of the working coil based on the detection result, and works based on the calculation result. By including a control unit for deriving the temperature of the coil, manufacturing workability can be improved.

The induction heating device according to the present invention can detect the temperature of the working coil without a temperature sensor, and thus, it is possible to prevent the problem of deteriorating temperature detection accuracy due to the distance tolerance between the upper plate and the temperature sensor, and by improving the temperature detection accuracy. It is possible to improve the accuracy of output control of the working coil and prevent product overheating.

In addition, since the induction heating device according to the present invention can detect the temperature of the working coil without a temperature sensor, it is not necessary to have a wire harness necessary to install the temperature sensor, and accordingly, manufacturing cost and manufacturing time can be reduced. I can.

In addition to the above-described effects, specific effects of the present invention will be described together while describing specific details for carrying out the present invention.

1 and 2 are views illustrating a temperature sensor provided in a conventional induction heating apparatus.
3 is a circuit diagram illustrating an induction heating device according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a series connection current path of FIG. 3.
5 and 6 are graphs illustrating a difference in resistance value of a working coil according to the presence or absence of an object to be heated in a switching frequency band.
7 is a flowchart illustrating an example of an output control method of the induction heating device of FIG. 3.
8 is a flowchart illustrating another example of an output control method of the induction heating device of FIG. 3.

The above-described objects, features, and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, one of ordinary skill in the art to which the present invention pertains will be able to easily implement 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 subject matter of the present invention, a detailed description 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 elements.

Hereinafter, when a component is described as being "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components are "connected" between each component. It is to be understood that intervening" or each component may be "connected", "coupled" or "connected" through other components.

Hereinafter, an induction heating device according to an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

3 is a circuit diagram illustrating an induction heating device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a series connection current path of FIG. 3. 5 and 6 are graphs illustrating a difference in resistance value of a working coil according to the presence or absence of an object to be heated in a switching frequency band.

For reference, FIG. 5 is a graph of the resistance value change of the working coil according to the frequency when the object to be heated is not present on the upper side of the working coil, and FIG. 6 is a working coil according to the frequency when the object to be heated is present on the upper side of the working coil. It is a graph of the resistance value change of.

First, referring to FIGS. 3 to 6, the induction heating device 1 according to an embodiment of the present invention includes a power supply unit 100, a rectification module RM, a working coil WC, a switch unit SWP, and a shunt resistor. (SR), a resonance capacitor unit (CRP), a snubber capacitor unit (CSP), an inverter unit (IV), a control unit 400, a gate driver 450 may be included.

The power supply unit 100 may output an AC current.

Specifically, the power supply unit 100 may output AC power and provide it to the rectification module RM, and may be, for example, a commercial power supply.

The rectification module RM may rectify the AC power output from the power supply unit 100 into DC power.

Specifically, the rectification module RM may include a rectifier 150, a DC link capacitor 200, a switched mode power supply (SMPS) 250, a voltage regulator 300, and a diode 350.

The rectifying unit 150 may rectify the AC power output from the power supply unit 100 into DC power.

That is, the rectification unit 150 is connected in parallel with the power supply unit 100, rectifies the AC power supplied from the power supply unit 100 to convert it into DC power, and provides the converted DC power to the DC link capacitor 200. .

The DC link capacitor 200 may reduce a ripple of DC power rectified by the rectifier 150.

That is, the DC link capacitor 200 is connected in parallel with the rectifier 150, reduces ripple of DC power provided from the rectifier 150, and converts DC power with reduced ripple into the SMPS 250 and the inverter unit IV. Can be provided as

In addition, the DC link capacitor 200 may include, for example, a smoothing capacitor.

In this way, the DC power rectified by the rectifying unit 150 and the DC link capacitor 200 may be supplied to the SMPS 250 and the inverter unit IV.

The SMPS 250 may rectify DC power with reduced ripple in the DC link capacitor 200.

That is, the SMPS 250 is connected in parallel with the DC link capacitor 200, rectifies DC power provided from the DC link capacitor 200, and provides the rectified DC power to the voltage regulator 300.

The voltage regulator 300 may limit the magnitude of the voltage of the DC power rectified by the SMPS 250 to a certain magnitude (eg, 5V).

That is, the voltage regulator 300 is connected in parallel with the SMPS 250, limits the voltage of DC power provided from the SMPS 250 to a certain size, and provides the voltage limited to a certain size to the diode 350. I can.

The diode 350 may provide a voltage limited to a predetermined size by the voltage regulator 300 to the working coil WC.

That is, one end of the diode 350 may be connected to the voltage regulator 300, and the other end of the diode 350 may be connected between the resonance capacitor unit CRP and the working coil WC. In addition, the diode 350 may provide a voltage of a predetermined size provided from the voltage regulator 300 to the working coil WC.

The inverter unit IV may receive DC power with a reduced ripple from the DC link capacitor 200, convert the DC power to a resonance current through a switching operation, and provide the DC power to the working coil WC.

Specifically, the inverter unit IV may be formed, for example, in the form of a half-bridge, is connected in parallel with the DC link capacitor 200, and is connected to the controller 400 and the gate driver 450 to be described later. The switching operation can be controlled by this. That is, the gate driver 450 may generate a switching signal based on a control signal provided from the control unit 400, and the inverter unit IV may perform a switching operation based on the switching signal provided from the gate driver 450. .

For reference, the inverter unit IV may include first and second switching elements S1 and S2 for performing a switching operation, and the two switching elements S1 and S2 are provided from the gate driver 450. It may be alternately turned on and turned off by a signal.

In addition, a high-frequency AC current (ie, a resonance current) may be generated by the switching operation of the two switching elements S1 and S2, and the generated high-frequency AC current may be applied to the working coil WC.

In addition, a snubber capacitor unit CSP may be connected to the inverter unit IV.

Specifically, the first switching element S1 may be connected to the first snubber capacitor CS1, and the second switching element S2 may be connected to the second snubber capacitor CS2.

The working coil WC may receive rectified DC power from the rectification module RM, and may receive a resonance current from the inverter unit IV.

Specifically, one end of the working coil WC may be connected to the resonance capacitor unit CRP, and the other end of the working coil WC may be connected to the snubber capacitor unit CSP.

In addition, an eddy current is generated between the working coil (WC) and the object to be heated (for example, a cooking vessel) by a high-frequency alternating current applied from the inverter unit (IV) to the working coil (WC). I can.

For reference, the working coil WC may receive rectified DC power from the rectifying module RM only when the switch unit SWP to be described later is turned on.

The resonance capacitor unit CRP is connected between one end of the working coil WC and the DC link capacitor 200, and may include first and second resonance capacitors CR1 and CR2.

Specifically, the resonance capacitor unit CRP may constitute a resonance circuit unit together with the working coil WC. In addition, in the case of the resonance capacitor unit CRP, when a voltage is applied by the switching operation of the inverter unit IV, resonance starts. In addition, when the resonance capacitor unit CRP resonates, the current flowing through the working coil WC connected to the resonance capacitor unit CRP increases.

Through this process, the eddy current is induced in the object to be heated disposed above the working coil WC connected to the resonant capacitor unit CRP.

The snubber capacitor unit CSP is connected between the other end of the working coil WC and the inverter unit IV, and may include first and second snubber capacitors CS1 and CS2.

Specifically, the snubber capacitor unit CSP includes a first snubber capacitor CS1 connected to the first switching element S1 and a second snubber capacitor CS2 connected to the second switching element S2. can do.

For reference, the first and second snubber capacitors CS1 and CS2 have power loss (that is, hard switching) that occurs when the first and second switching elements S1 and S2 are turned off. ), and can be used to remove electromagnetic wave noise in some cases.

The gate driver 450 is driven based on a driver driving voltage supplied from an external power source (not shown), and may be connected to the inverter unit IV to control a switching operation of the inverter unit IV.

In addition, the gate driver 450 may control the inverter unit IV based on a control signal provided from the controller 400. That is, the gate driver 450 may turn on or off the first and second switching elements S1 and S2 included in the inverter unit IV based on the control signal.

For reference, the gate driver 450 includes first and second sub-switch driving units (not shown) that turn on or off the first and second switching elements S1 and S2, respectively. It should be omitted.

In the case of the switch unit SWP, one end may be connected to the working coil WC, and the other end may be connected to the shunt resistor SR.

That is, one end of the switch unit SWP may be connected between the working coil WC and the snubber capacitor unit CSP, and the other end of the switch unit SWP may be connected to the shunt resistor SR.

In addition, turn-on and turn-off of the switch unit SWP may be controlled by the controller 400.

That is, when the switch unit SWP is turned on by the control unit 400, the direct current power rectified in the rectification module RM is applied to the shunt resistor SR through the working coil WC and the switch unit SWP. I can. On the other hand, when the switch unit SWP is turned off by the control unit 400, the DC power rectified in the rectification module RM may not be applied to the shunt resistor SR.

In addition, the switch unit SWP may be turned on by the control unit 400 every preset period.

For reference, since information related to a preset period is stored in the controller 400, the controller 400 may turn on the switch unit SWP at every preset period from the moment the induction heating device 1 is turned on. .

The shunt resistor SR may be connected to the other end of the switch unit SWP.

That is, the shunt resistor SR is connected to the other end of the switch unit SWP, and when the switch unit SWP is turned on, as shown in FIG. 4, the working coil WC and the shunt resistor SR are A series connected current path comprising can be formed. Accordingly, the voltage of the DC power rectified by the rectification module RM may be distributed to the working coil WC and the shunt resistor SR based on resistance values of the working coil WC and the shunt resistor SR.

For reference, since the shunt resistance (SR) is a resistance that exists to measure the resistance value of the working coil (WC), a resistance value that is considerably small enough to not interfere with the measurement of the resistance value of the working coil (WC) (for example, 0.68Ω; a resistance value between 0 and 2Ω).

The control unit 400 turns on the switch unit SWP at each preset period so that the DC power rectified in the rectification module RM is applied to the shunt resistor SR through the working coil WC, and the shunt resistance SR Control to detect the voltage of DC power applied to the device, to determine whether the temperature of the working coil (WC) exists within the safe temperature range based on the detection result, and to control the output of the working coil (WC) based on the determination result Can generate signals.

Here, as shown in Figs. 5 and 6, in the switching operation frequency band of the inverter unit IV (i.e., several tens of kHz band (for example, 30 kHz)), even in the same frequency band, the working coil WC It can be seen that the resistance value of the working coil WC greatly differs depending on whether there is an object to be heated on the upper side of ).

However, when determining the resistance value of the working coil WC in the situation where the above-described series-connected current path is formed, the resistance value of the working coil WC does not change depending on the presence or absence of the heating object, but instead of the working coil ( WC) may fluctuate with increasing temperature.

For example, when the size of the working coil (WC) is 7 inches (inch), and the temperature of the working coil (WC) is 25°C, 50°C, and 100°C, respectively, the resistance value of the working coil (WC) is 34.84, respectively. It may be mΩ, 37.99mΩ, 43.53mΩ.

In addition, when the size of the working coil (WC) is 10 inches (inch) and the temperature of the working coil (WC) is 25°C, 50°C, and 100°C, respectively, the resistance values of the working coil (WC) are 31.89mΩ and 34.78, respectively. It may be mΩ, 38.73mΩ.

For this reason, in the embodiment of the present invention, the control unit 400 determines the temperature of the working coil WC based on the resistance value of the working coil WC (or the magnitude of the voltage of the DC power applied to the shunt resistor SR). Perform analogy work.

For reference, the control unit 400 may control the switch unit SWP in a turn-off state for the rest of the time excluding a point in time when a preset period has arrived.

That is, when a preset cycle has arrived, the control unit 400 turns on the switch unit SWP, and when a new cycle starts again after the preset cycle arrives, the control unit 400 turns on the switch unit SWP. ) Is turned off, and when a preset period has not arrived after a new period has started, the controller 400 may maintain the turn-off state of the switch unit SWP.

In addition, the control unit 400 may provide the generated control signal to the gate driver 450.

Accordingly, the gate driver 450 controls the switching operation of the first and second switching elements S1 and S2 based on the received control signal, and the output of the working coil WC is controlled through this control process. will be.

More specifically, the control unit 400 may compare the detected voltage of DC power with a preset voltage, and determine whether the temperature of the working coil WC exists within the safe temperature range based on the comparison result. have. Also, the controller 400 may generate a control signal for controlling the output of the working coil WC based on the determination result, and may provide the generated control signal to the gate driver 450.

Here, when the magnitude of the voltage of the sensed DC power is greater than the magnitude of the preset voltage (including the same case), the controller 400 determines that the temperature of the working coil WC exists within the safe temperature range, and determines Based on the result, a control signal for maintaining or increasing the output of the working coil WC may be generated.

Of course, the controller 400 may determine whether to maintain or increase the output of the working coil WC according to the magnitude of the sensed voltage of the DC power. Further, when it is determined to increase the output of the working coil WC, the control unit 400 may determine an increase width of the output of the working coil WC according to the magnitude of the voltage of the sensed DC power.

On the other hand, when the magnitude of the voltage of the sensed DC power is smaller than the magnitude of the preset voltage, the control unit 400 determines that the temperature of the working coil WC does not exist within the safe temperature range, and based on the determination result, the working coil A control signal for reducing the output of the WC or stopping driving of the working coil WC may be generated.

Of course, the control unit 400 may determine whether to reduce the output of the working coil WC or stop driving itself according to the magnitude of the sensed DC power voltage. Further, when it is determined to reduce the output of the working coil WC, the control unit 400 may determine a reduction width of the output of the working coil WC according to the magnitude of the detected voltage of the DC power.

For reference, the size of the preset voltage is the minimum voltage value (i.e., the working coil WC) that must be distributed (i.e., applied) to the shunt resistor (SR) so that the temperature of the working coil (WC) does not reach an overheating state. It can be set to a minimum voltage value that must be distributed across the shunt resistor (SR) in order for the protection mechanism against overheating (e.g., reducing the power of the working coil (WC) or stopping the operation of the working coil (WC)) to be executed. have.

Accordingly, the safe temperature range of the working coil WC is also a temperature range for not reaching the above-described overheating state (for example, a temperature value lower than the temperature attaining overheating from 0°C to a certain level; If the upper limit is set, the risk of reaching an overheating state increases, and thus the upper limit of the safe temperature range is set to a temperature value lower than the overheating temperature by a certain level).

Meanwhile, the control unit 400 may generate a control signal in a method different from the above-described control signal generation method.

That is, the controller 400 may sense the magnitude of the voltage distributed to the shunt resistor SR, and calculate the magnitude of the voltage distributed to the working coil WC and the resistance value of the working coil WC based on the detection result. .

Specifically, when the switch unit (SWP) is turned on, a series-connected current path including a working coil (WC) and a shunt resistor (SR) is formed, and the voltage of the DC power rectified in the rectifying module RM is applied to the working coil. Based on the resistance values of (WC) and shunt resistance (SR), they are distributed to the working coil (WC) and shunt resistance (SR). Accordingly, the control unit 400 can derive a current value flowing in the series connection current path and the magnitude of the voltage of the working coil WC based on the magnitude of the voltage of the shunt resistor SR, and the current flowing in the series connection current path The resistance value of the working coil WC may be calculated based on the value and the magnitude of the voltage of the working coil WC.

In addition, the control unit 400 derives the temperature of the working coil WC based on the calculation result, compares the temperature of the derived working coil WC with a preset temperature, and the temperature of the working coil WC is determined based on the comparison result. Whether it is within a safe temperature range can be determined. Also, the controller 400 may generate a control signal for controlling the output of the working coil WC based on the determination result, and may provide the generated control signal to the gate driver 450.

Here, when the derived temperature of the working coil WC is lower than the preset temperature (including the same case), the control unit 400 determines that the temperature of the working coil WC is within the safe temperature range, and the determination result Based on this, a control signal for maintaining or increasing the output of the working coil WC may be generated.

Of course, the controller 400 may determine whether to maintain or increase the output of the working coil WC according to the sensed temperature value of the working coil WC. Further, when it is determined to increase the output of the working coil WC, the controller 400 may determine an increase in the output of the working coil WC according to the sensed temperature value of the working coil WC.

On the other hand, when the temperature of the derived working coil WC is higher than a preset temperature, the control unit 400 determines that the temperature of the working coil WC does not exist within the safe temperature range, and based on the determination result, the working coil ( A control signal for reducing the output of WC) or stopping driving of the working coil WC may be generated.

Of course, the control unit 400 may determine whether to reduce the output of the working coil WC or stop driving itself according to the sensed temperature value of the working coil WC. Furthermore, when it is determined to reduce the output of the working coil WC, the control unit 400 may determine a reduction width of the output of the working coil WC according to the sensed temperature value of the working coil WC.

For reference, the preset temperature is a temperature value lower than the overheating temperature by a certain level (that is, a protection mechanism according to overheating of the working coil (WC) (for example, reducing the power of the working coil (WC) or reducing the power of the working coil (WC))). Stopped operation) can be set to an upper temperature limit for not being executed.

Accordingly, the safe temperature range of the working coil (WC) is also set based on a preset temperature (for example, 0°C to a preset temperature; when the temperature value immediately before the overheating temperature is set as the upper limit, the overheating state is reached. As the risk increases, the upper limit of the safe temperature range (ie, a preset temperature) may be set to a temperature value lower than the overheating temperature by a certain level.

As described above, the induction heating device 1 according to the embodiment of the present invention has the above-described configuration and features. Hereinafter, with reference to FIG. 7, the output of the induction heating device 1 according to the embodiment of the present invention Let's explain the control method.

7 is a flowchart illustrating an example of an output control method of the induction heating device of FIG. 3.

For reference, FIG. 7 is an output control method related to an example of a method for generating a control signal of the control unit 400 described above (that is, a method for generating a control signal based on the magnitude of the voltage of DC power detected by the shunt resistor SR) Is shown.

3 and 7, first, it is determined whether or not a preset period has arrived (S100).

Specifically, when a preset cycle has arrived, the control unit 400 turns on the switch unit SWP (S150), and when a new cycle starts again after the preset cycle arrives, the control unit 400 turns on The switch unit SWP is turned off, and when a preset period has not arrived after a new period has started, the controller 400 may maintain the turn-off state of the switch unit SWP (S170).

When the switch unit SWP is turned on (S150), the voltage of the shunt resistor SR is sensed (S200).

Specifically, when the switch unit (SWP) is turned on by the control unit 400, a series-connected current path including a working coil (WC) and a shunt resistor (SR) is formed, and the direct current rectified by the rectifying module (RM) The voltage of the power may be distributed to the working coil WC and the shunt resistor SR based on resistance values of the working coil WC and the shunt resistor SR.

Subsequently, when the voltage of the DC power rectified by the rectification module RM is distributed to the shunt resistor SR, the controller 400 senses the voltage of the DC power distributed to the shunt resistor SR.

After sensing the voltage of the shunt resistor SR (S200), the voltage of the shunt resistor SR is compared with a preset voltage (S250).

Specifically, the control unit 400 compares the magnitude of the sensed DC power voltage (that is, the voltage of the shunt resistor SR) with the magnitude of the preset voltage, and the temperature of the working coil WC is safe based on the comparison result. Whether it is within the temperature range can be determined. In addition, the controller 400 may generate a control signal for controlling the output of the working coil WC based on the determination result.

More specifically, when the magnitude of the voltage of the sensed DC power is greater than the magnitude of the preset voltage, the control unit 400 determines that the temperature of the working coil WC is within the safe temperature range, and based on the determination result, the working coil It is possible to generate a control signal for maintaining or increasing the output of (WC).

On the other hand, when the magnitude of the voltage of the sensed DC power is smaller than the magnitude of the preset voltage, the control unit 400 determines that the temperature of the working coil WC does not exist within the safe temperature range, and based on the determination result, the working coil A control signal for reducing the output of the WC or stopping driving of the working coil WC may be generated.

The control unit 400 may provide the generated control signal to the gate driver 450. Accordingly, the gate driver 450 controls the switching operation of the first and second switching elements S1 and S2 based on the received control signal, and the output of the working coil WC is controlled through this control process. will be.

More specifically, when a control signal for maintaining or increasing the output of the working coil WC is provided to the gate driver 450, the gate driver 450 may be configured with the first and second switching elements S1 based on the received control signal. , S2) to control the switching operation, the output of the working coil (WC) is maintained or increased (S300).

On the other hand, when a control signal for reducing the output of the working coil WC or stopping the driving of the working coil WC is provided to the gate driver 450, the gate driver 450 provides a control signal based on the received control signal. As the switching operation of the first and second switching elements S1 and S2 is controlled, the output of the working coil WC is reduced or the driving of the working coil WC is stopped (S330).

An example of a method for controlling the output of the induction heating device may be performed based on the above-described process. Hereinafter, referring to FIG. 8, a method for controlling the output of the induction heating device 1 according to an embodiment of the present invention will be described. do.

8 is a flowchart illustrating another example of an output control method of the induction heating device of FIG. 3.

For reference, FIG. 8 illustrates an output control method related to another example of the control signal generation method of the control unit 400 described above (ie, a control signal generation method based on the derived temperature of the working coil WC).

3 and 8, first, it is determined whether or not a preset period has arrived (S100).

Specifically, when a preset cycle has arrived, the control unit 400 turns on the switch unit SWP (S150), and when a new cycle starts again after the preset cycle arrives, the control unit 400 turns on The switch unit SWP is turned off, and when a preset period has not arrived after a new period has started, the controller 400 may maintain the turn-off state of the switch unit SWP (S170).

When the switch unit SWP is turned on (S150), the voltage of the shunt resistor SR is sensed (S200).

Specifically, when the switch unit (SWP) is turned on by the control unit 400, a series-connected current path including a working coil (WC) and a shunt resistor (SR) is formed, and the direct current rectified by the rectifying module (RM) The voltage of the power may be distributed to the working coil WC and the shunt resistor SR based on resistance values of the working coil WC and the shunt resistor SR.

Subsequently, when the voltage of the DC power rectified by the rectification module RM is distributed to the shunt resistor SR, the controller 400 may detect the magnitude of the voltage of the DC power distributed to the shunt resistor SR.

When the magnitude of the voltage distributed to the shunt resistor SR is sensed (S200), the magnitude of the voltage and the resistance value of the working coil WC are calculated (S260).

Specifically, the control unit 400 may calculate a magnitude of a voltage distributed to the working coil WC and a resistance value of the working coil WC based on the detection result.

That is, the control unit 400 can derive a current value flowing in the series connection current path and a voltage level of the working coil WC based on the magnitude of the voltage of the shunt resistor SR, and the current value flowing in the series connection current path And a resistance value of the working coil WC may be calculated based on the magnitude of the voltage of the working coil WC.

When the voltage magnitude and resistance value of the working coil WC is calculated (S260), the temperature of the working coil WC is derived (S270).

Specifically, the control unit 400 may derive the temperature of the working coil WC based on the calculation result.

That is, as described above, when determining the resistance value of the working coil WC in a situation in which a series-connected current path is formed, the resistance value of the working coil WC does not change depending on the presence or absence of an object to be heated. As the temperature of the working coil WC changes, the controller 400 may derive the temperature of the working coil WC based on the resistance value of the working coil WC.

When the temperature of the working coil WC is derived (S270), the temperature of the derived working coil WC is compared with a preset temperature (S280).

Specifically, the control unit 400 may compare the derived temperature of the working coil WC with a preset temperature, and determine whether the temperature of the working coil WC exists within a safe temperature range based on the comparison result. In addition, the controller 400 may generate a control signal for controlling the output of the working coil WC based on the determination result.

More specifically, when the temperature of the derived working coil WC is lower than a preset temperature, the control unit 400 determines that the temperature of the working coil WC is within the safe temperature range, and based on the determination result, the working coil ( WC) can generate a control signal to maintain or increase the output.

On the other hand, when the temperature of the derived working coil WC is higher than a preset temperature, the control unit 400 determines that the temperature of the working coil WC does not exist within the safe temperature range, and based on the determination result, the working coil ( A control signal for reducing the output of WC) or stopping driving of the working coil WC may be generated.

The control unit 400 may provide the generated control signal to the gate driver 450. Accordingly, the gate driver 450 controls the switching operation of the first and second switching elements S1 and S2 based on the received control signal, and the output of the working coil WC is controlled through this control process. will be.

More specifically, when a control signal for maintaining or increasing the output of the working coil WC is provided to the gate driver 450, the gate driver 450 may be configured with the first and second switching elements S1 based on the received control signal. , S2) to control the switching operation, the output of the working coil (WC) is maintained or increased (S300).

On the other hand, when a control signal for reducing the output of the working coil WC or stopping the driving of the working coil WC is provided to the gate driver 450, the gate driver 450 provides a control signal based on the received control signal. As the switching operation of the first and second switching elements S1 and S2 is controlled, the output of the working coil WC is reduced or the driving of the working coil WC is stopped (S330).

As described above, in the induction heating apparatus 1 according to the embodiment of the present invention, the output of the working coil WC is directly or indirectly controlled based on the temperature of the working coil WC, so that more efficient output control is possible than the conventional one. .

As described above, the induction heating apparatus 1 according to the embodiment of the present invention can detect the temperature of the working coil without a temperature sensor, and thus, the problem of deteriorating the temperature detection accuracy due to the distance tolerance between the upper plate part and the temperature sensor. It can be prevented, and it is possible to improve the accuracy of output control of the working coil and prevent product overheating by improving the temperature sensing accuracy.

In addition, since the induction heating device 1 according to the embodiment of the present invention can sense the temperature of the working coil without a temperature sensor, it is not necessary to have a wire harness necessary to install the temperature sensor, and thus, manufacturing cost And manufacturing time can be reduced.

As described above with reference to the drawings illustrated for the present invention, the present invention is not limited by the embodiments and drawings disclosed in the present specification, and various by a person skilled in the art within the scope of the technical idea of the present invention. It is obvious that transformation can be made. In addition, even if not explicitly described and described the effects of the configuration of the present invention while describing the embodiments of the present invention, it is natural that the predictable effects of the configuration should also be recognized.

100: power supply unit 150: rectification unit
200: DC link capacitor 250: SMPS
300: voltage regulator 350: diode
400: control unit 450: gate driver
RM: Rectification module SWP: Switch unit
SR: shunt resistance WC: working coil
IV inverter part

Claims (14)

A power supply for outputting AC power;
A rectifying module for rectifying the AC power output from the power supply into DC power;
A working coil receiving the rectified DC power from the rectifying module;
A switch unit having one end connected to the working coil;
A shunt resistor connected to the other end of the switch unit; And
The switch unit is turned on at every preset period so that the DC power rectified by the rectifying module is applied to the shunt resistor via the working coil, and detects the voltage of the DC power applied to the shunt resistor, based on the detection result. Comprising a control unit for determining whether the temperature of the working coil is within a safe temperature range, and generating a control signal for controlling the output of the working coil based on the determination result
Induction heating device.
The method of claim 1,
The rectification module,
A rectifier for rectifying the AC power output from the power supply to DC power,
A DC link capacitor for reducing ripple of DC power rectified by the rectifying unit,
A switched mode power supply (SMPS) for rectifying DC power with reduced ripple in the DC link capacitor,
A voltage regulator limiting the voltage level of the DC power rectified in the SMPS to a certain level,
Including a diode for providing the voltage limited to the predetermined size in the voltage regulator to the working coil
Induction heating device.
The method of claim 2,
An inverter unit provided with first and second switching elements for receiving DC power with reduced ripple from the DC link capacitor, converting the received DC power into a resonance current through a switching operation, and providing it to the working coil;
A gate driver controlling the switching operation of the first and second switching elements;
A resonance capacitor part connected between one end of the working coil and the DC link capacitor; And
Further comprising a snubber capacitor unit connected between the other end of the working coil and the inverter unit
Induction heating device.
The method of claim 3,
The control unit provides the generated control signal to the gate driver,
The gate driver controls the switching operation of the first and second switching elements based on the received control signal.
Induction heating device.
The method of claim 3,
The rectifying unit is connected in parallel with the power supply unit,
The DC link capacitor is connected in parallel with the rectifier,
The SMPS is connected in parallel with the DC link capacitor,
The voltage regulator is connected in parallel with the SMPS,
One end of the diode is connected to the voltage regulator, and the other end of the diode is connected between the resonance capacitor part and the working coil,
The inverter unit is connected in parallel with the DC link capacitor
Induction heating device.
The method of claim 1,
When the switch unit is turned on by the control unit, direct current power rectified in the rectifying module is applied to the shunt resistor through the working coil and the switch unit,
When the switch unit is turned off by the control unit, the DC power rectified in the rectifying module is not applied to the shunt resistor.
Induction heating device.
The method of claim 1,
When the preset period has arrived, the control unit turns on the switch unit,
When a new cycle starts again after the preset cycle arrives, the control unit turns off the turned-on switch unit,
When the preset period does not arrive after the new period starts, the control unit maintains the turn-off state of the switch unit.
Induction heating device.
The method of claim 1,
The control unit,
Compare the sensed voltage of DC power with a preset voltage,
Based on the comparison result, it is determined whether the temperature of the working coil is within the safe temperature range,
Generating the control signal for controlling the output of the working coil based on the determination result
Induction heating device.
The method of claim 8,
When the voltage of the sensed DC power is larger than the preset voltage,
The control unit determines that the temperature of the working coil is within the safe temperature range, and generates the control signal for maintaining or increasing the output of the working coil based on the determination result.
Induction heating device.
The method of claim 8,
When the voltage of the sensed DC power is smaller than the preset voltage,
The control unit determines that the temperature of the working coil does not exist within the safe temperature range, and generates the control signal for reducing the output of the working coil or stopping driving of the working coil based on the determination result.
Induction heating device.
The method of claim 1,
When the switch unit is turned on,
A series connection current path including the working coil and the shunt resistor is formed,
The voltage of the DC power rectified in the rectifying module is distributed to the working coil and the shunt resistor based on resistance values of each of the working coil and the shunt resistor.
Induction heating device.
The method of claim 11,
The control unit,
Detects the magnitude of the voltage distributed to the shunt resistor,
Based on the detection result, the magnitude of the voltage distributed to the working coil and the resistance value of the working coil are calculated,
Derive the temperature of the working coil based on the calculation result,
Compare the temperature of the derived working coil with a preset temperature,
It is determined whether the temperature of the working coil is within the safe temperature range based on the comparison result,
Generating the control signal for controlling the output of the working coil based on the determination result
Induction heating device.
The method of claim 12,
When the temperature of the derived working coil is lower than the preset temperature,
The control unit determines that the temperature of the working coil exists within the safe temperature range, and generates the control signal for maintaining or increasing the output of the working coil based on the determination result.
Induction heating device.
The method of claim 12,
When the temperature of the derived working coil is higher than the preset temperature,
The control unit determines that the temperature of the working coil does not exist within the safe temperature range, and generates the control signal for reducing the output of the working coil or stopping driving of the working coil based on the determination result.
Induction heating device.

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