KR20110019500A - Switching element protecting apparatus for induction heating cooker - Google Patents

Abstract

PURPOSE: A switching element protecting apparatus for an induction heating cooker is provided to maintain a resonance voltage to be lower than the internal voltage of a switching element by directly controlling the turn-on time of the switching element. CONSTITUTION: A resonance part, a power source part(12), a switching element part, a voltage detecting part, a driving part(13), and a microcomputer(MICOM)(15). The power source part applies a driving voltage to the resonance part. The switching element part supplies and breaks a current into the resonance part according to turn-on and turn-off signals. The voltage detecting part applies a voltage value corresponding to the driving voltage or the supply time of the current if the current is supplied to the resonance part. The driving part applies the turn-on and turn-off signals to the switching element part. The MICOM generates a controlling signal and applies the controlling signal to the driving part.

Description

Switching element protection device of induction heating cooker {SWITCHING ELEMENT PROTECTING APPARATUS FOR INDUCTION HEATING COOKER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for protecting a switching element of an induction heating cooker. In particular, an induction heating cooker which shortens the on time of a switching element by using a sensing value in response to a supply time of a driving voltage to a switching element and a magnitude of the driving voltage. It relates to a switching device protection device of.

Induction heating cooker performs a cooking function by the way in which the eddy current flows when the magnetic wire generated from the working coil passes through the pot. Looking at the basic heating principle of the induction cooker, when a current is applied to the working coil, the oven is a magnetic material is heated by induction heating (heating), the inside of the oven is heated and cooked.

Therefore, in the case of an induction heating cooker, a high frequency voltage of a predetermined magnitude must be applied to the working coil in order to generate magnetic lines. At this time, the working coil has a strong thermal power of about 1300W by the applied high frequency voltage. The working coil

It is the switching element to be applied.

1 is a block diagram of a switching device protection device of the induction heating cooker according to the prior art.

The induction heating cooker rectifies and smoothes a commercial AC power source (AC power source) 1 to a DC voltage, and a resonator unit (capacitor C) that receives a DC voltage (or driving voltage) from the power source unit 2. And a protection coil connected between the working coil L, a switching element IGBT for supplying and blocking a DC voltage to the resonator, and a CG terminal of the switching element IGBT to protect the switching element IGBT. Receives a control signal from the microcomputer (series connection circuit of Zener diode ZD1 and diode D) and the microcomputer 5, and applies an on signal and an off signal corresponding to the control signal to the switching element IGBT. In addition, the driving unit 3 which supplies and cuts the driving voltage to the switching element IGBT, receives the AC power source 1 and the resonance voltage, and compares the magnitude of the AC power source 1 with the magnitude of the resonance voltage. The retrigger part 4 which applies a comparison signal to the microcomputer 5, and the whole ball | bowl of an induction heating cooker. The control and comprises a microcomputer (5) for adjusting a control signal (on and off) in accordance with the comparison signal from the applied control signals to the drive unit 3, and controls the induction heating, re-tree refused (4).

The microcomputer 5 of FIG. 1 receives a comparison signal from the retrigger unit 4 comparing the resonant voltage of the switching element IGBT with the level of the AC power source 1, and if the resonant voltage is high, the switching element ( The on time of the IGBT is reduced to apply a control signal corresponding to the reduced on signal to the driver 3. If the resonance voltage is low, the microcomputer 5 increases the on time of the switching element IGBT to provide a control signal corresponding to the increased on signal.

It applies to the drive part 3.

In the microcomputer 5 that controls the switching element IGBT, when the on time of the switching element IGBT due to a malfunction is long, there is a problem that the switching element IGBT is broken. That is, although the on time is adjusted, the resonance voltage is not prevented from increasing instantaneously, and the resonance voltage can only be gradually lowered after the resonance voltage is increased.

In addition, if the power supply distortion or the power supply voltage is higher than usual, the on-time of the switching element IGBT should be reduced to prevent the overcurrent and over-resonance voltage of the switching element IGBT. Due to the delay, the on-time of the switching element IGBT cannot be controlled at the time when the power supply voltage rises, resulting in overcurrent and overresonant voltage, which can also lead to breakage of the switching element IGBT.

In addition, when power distortion or momentary power failure occurs, the resonance voltage rises higher than the withstand voltage of the switching element IGBT, which may damage the switching element. However, the protection unit is used, but the resonance voltage is increased due to the error of the zener diode ZD1 in the protection unit. There exists a possibility that it may become higher than the withstand voltage of switching element IGBT.

The present invention directly adjusts the on time of the switching element IGBT even for a driving voltage that is variable in conjunction with an AC voltage (power supply voltage), so that the resonance voltage is maintained below the withstand voltage of the switching element IGBT. An object of the present invention is to provide a switching device protection device for a cooker.

In addition, an object of the present invention is to provide a switching element protection device of an induction heating cooker that can independently control the on time of the switching element (IGBT) in the drive unit without controlling the microcomputer.

In addition, an object of the present invention is to provide a switching element protection device for an induction heating cooker capable of controlling the on time of the switching element (IGBT) quickly and accurately even when the magnitude of the driving voltage (or AC power source) changes.

The switching element protection device of the induction heating cooker of the present invention is supplied with a resonator, a commercial AC power supply, a power supply unit applying a driving voltage to the resonator unit, and supplying and blocking current to the resonator unit according to on and off signals. A switching element unit, a voltage sensing unit for applying a voltage value corresponding to the supply time of the current or the magnitude of the driving voltage when the current is supplied to the resonant unit, and switching in response to a control signal from the microcomputer Apply the on signal and the off signal to the device

If the control signal is an on signal and the voltage value from the voltage sensing unit is greater than or equal to the reference magnitude, the driving unit applies an off signal to the switching element unit, and generates and applies the control signal to the driving unit to control induction heating by the resonator unit. It is made with a microcomputer.

In addition, when the control signal of the microcomputer is an off signal, the driver applies the off signal to the switching element independently of the voltage value from the voltage sensing unit, and the control signal of the microcomputer is the on signal and the voltage from the voltage sensing unit. When the value is less than the reference magnitude, it is preferable to apply the on signal to the switching element portion.

In addition, when the driving voltage is greater than or equal to the first size, the voltage sensing unit is charged by receiving a first current applying unit for applying a current according to the magnitude of the driving voltage, a current from the first current applying unit, and a constant current from the driving unit. Preferably, a capacitor unit is provided, and the driving unit receives a voltage value charged in the capacitor unit.

In addition, when the control signal of the microcomputer is the ON signal, the driving unit preferably applies a constant current to the capacitor unit.

In addition, the first current applying unit preferably includes a first resistor connected in series to the capacitor unit.

In addition, the voltage sensing unit is connected in parallel to the first current applying unit, the second current having a second resistor, and applying a current according to the magnitude of the driving voltage when the driving voltage is greater than or equal to the second size greater than the first size It is preferable to provide an application part.

In addition, the driving unit is operated according to the input unit receiving a control signal from the microcomputer and the control signal from the microcomputer, and the voltage value and the reference value from the voltage sensing unit.

 Preferably, a comparison section for comparing magnitudes and an output section for applying an on signal and an off signal to the switching element section in accordance with a control signal from the input section and a comparison result from the comparison section or in accordance with a control signal from the input section.

According to the present invention, the on-time of the switching element IGBT is directly adjusted even for the driving voltage which is variable in conjunction with the AC voltage (power supply voltage), so that the resonance voltage is kept below the withstand voltage of the switching element IGBT. have.

In addition, the present invention has the effect that it is possible to protect the switching element (IGBT) of the induction heating cooker quickly and accurately, even in the malfunction of the microcomputer by controlling the on time of the switching element (IGBT) independently from the driver without controlling the microcomputer. .

In addition, the present invention has the effect of being able to control the ON time of the switching element IGBT quickly and accurately even in the variation of the magnitude of the driving voltage (or AC power supply).

In the following, the invention is described in detail by way of examples and drawings.

2 is a block diagram of a switching device protection device of the induction heating cooker according to the present invention.

The switching element protection device of FIG. 2 includes a power supply unit 12 for rectifying and smoothing a commercial AC power supply 11 to a DC voltage, and a resonator unit receiving a driving voltage (or DC voltage) from the power supply unit 12 ( Capacitor (C) and working coil (L), a switching element portion for supplying and blocking current by a DC voltage to the resonator portion, and a driving voltage when current flows to the resonator portion, that is, when current is supplied to the resonator portion, A voltage sensing unit for applying a voltage value corresponding to the supply time of the current or the magnitude of the driving voltage, and an on signal and an off signal to the switching element IGBT in response to a control signal from the microcomputer 15 , The driving unit 13 which receives the voltage value from the voltage sensing unit and converts the ON signal of the switching element IGBT in consideration of the applied voltage value, and receives the AC power source 11 and the resonant voltage. Ratio between the magnitude of 11 and the magnitude of the resonant voltage The retrigger unit 14 for applying the comparison signal through the microcomputer 15 and the induction heating by the resonator unit to control the entire process of the induction heating cooker, and generates a control signal to the drive unit 13 It consists of the microcomputer 15 to apply. The induction heating cooker may include an additional power source for supplying power required for components such as the driving unit 13, the retrigger unit 14, and the microcomputer 15, or the power supply unit 12 may supply the necessary power.

The AC power source 11, the power source unit 12, and the resonator unit are provided in a general induction heating cooker, and detailed description thereof is omitted.

The switching element unit is connected between the switching element IGBT and the CG terminal of the switching element IGBT to perform the current supply and interruption to the resonator in accordance with the on signal and the off signal from the driving unit 13, and the switching element IGBT. ) And a basic protection unit (a series connection circuit of the zener diode ZD1 and the diode D). but,

The switching element portion may not include a basic protection portion.

The voltage sensing unit applies a voltage value corresponding to the supply time of the current corresponding to the driving voltage from the power supply unit 12 to the resonance unit and / or the magnitude of the driving voltage to the driving unit 13. To this end, the voltage sensing unit receives a current of a predetermined magnitude from the S terminal of the driving unit 13, and a capacitor unit receiving current from the first current applying unit 24 or the second current applying unit 26 ( 22), when the magnitude of the driving voltage applied to the resonator is greater than or equal to the first magnitude, when the magnitude of the first current applying portion 24 to allow current to conduct, and the magnitude of the drive voltage to be applied to the resonator is greater than or equal to the second magnitude. And a second current applying unit 26 for allowing current to be conducted.

The capacitor part 22 has one end connected to the S terminal of the driving unit 13, the capacitor C1 connected to the first and second current applying units 24 and 26 and the other end grounded, and the capacitor C1. The Zener diode ZD2 is connected in parallel. Accordingly, the capacitor unit 22 is charged by receiving a current from the driving unit 13, the first current applying unit 24, or the second current applying unit 26 at the time of controlling the resonance of the resonator unit.

The first current applying unit 24 includes a zener diode ZD3 and a resistor R1 connected in series with the zener diode ZD3. When the driving voltage having the magnitude (that is, the first size) equal to or greater than the breakdown voltage of the zener diode ZD3 is applied to the resonator, the first current applying unit 24 flows a current. When the current is applied only through the first current applying unit 24, the current from the first current applying unit 24 and the constant current from the driving unit 13 are applied to the capacitor unit 22 so that the capacitor C1 is applied. Is charged.

The second current applying unit 26 includes two Zener diodes ZD4 and ZD5 connected in series, and a resistor R2 connected in series to the Zener diodes ZD4 and ZD5. When the driving voltage having the magnitude (that is, the second size) equal to or greater than the breakdown voltage of the two zener diodes ZD4 and ZD5 is applied to the resonator, the second current applying unit 26 flows the current. That is, the second size of the second current applying unit 26 becomes a relatively larger value than the first size of the first current applying unit 24.

When the driving voltage is less than the first size, no current is applied through the first current applying unit 24 and the second current applying unit 26.

When the driving voltage is greater than or equal to the first magnitude and less than the second magnitude (for example, low voltage), as described above, current is applied only through the first current applying unit 24, and when the driving voltage is greater than or equal to the second magnitude ( For example, a current is applied through the high voltage), the first and second current applying units 24 and 26. In the case of the low voltage, the time constant at the time of charging the capacitor C1 is affected by the capacitor C1 and the resistance value (internal resistance of the R1 + Zener diode ZD3). On the other hand, in the case of high voltage, the time constant at the time of charging the capacitor C1 is the capacitor C1 and the resistance values ((internal resistance of the R1 + Zener diode ZD3) and (internal resistance of the R2 + Zener diodes ZD4 and ZD5). The parallel connection resistance between Accordingly, since the resistance value at the low voltage is larger than the resistance value at the high voltage, the capacitor C1 is charged more quickly at the high voltage, and the fast charging is performed by the driving unit 13 more quickly. You can do that.

The second current applying unit 26 may be selectively provided, but at higher voltages.

There is an advantageous effect that the charging of the fast capacitor portion 22 is made. In addition, the magnitude or the voltage value of the voltage charged in the capacitor unit 22 corresponds to the time when the driving voltage is supplied (that is, the time when the current is conducted and the current is supplied), and also increases in response to the magnitude of the driving voltage. It can be seen. The voltage sensing unit performs the above-described operation when a current caused by the driving voltage flows in the resonance unit.

The driving unit 13 includes an input unit 13a receiving a control signal from the microcomputer 15 through the input terminal I, a comparison unit 13b for comparing the voltage value from the voltage sensing unit with a reference magnitude, and the input unit ( According to the control signal from 13a and / or the comparison result from the comparison section 13b, the output section 13c applies an on signal and an off signal to the switching element section.

In detail, when the input unit 13a receives the off signal from the microcomputer 15, the off signal is applied to the output unit 13c. In this case, the input unit 13a does not apply a proper signal to the comparator 13b or applies no signal, so that the comparator 13b does not apply a constant current to the voltage detector. That is, during the off control, the driving voltage is not applied to the resonator unit, so the voltage sensing unit need not be driven. Accordingly, when the driver 13 receives the control signal, which is an off signal, from the microcomputer 15, the driver 13 does not need to detect the voltage value from the voltage detector, that is, independently of the voltage value from the voltage detector. Is applied to the switching element.

When the input unit 13a receives a signal from the microcomputer 15, the input unit 13a applies an on signal to the output unit 13c, and an appropriate signal is applied to the comparing unit 13b or no signal is applied.

By not applying, the comparator 13b applies a constant current to the voltage sensing unit, and the comparator 13b senses the voltage value charged in the capacitor unit 22. The comparator 13b stores the reference magnitude of the voltage value and compares the magnitude of the sensed voltage value with the reference magnitude. For example, the reference size may be set as 6V or the like. This reference magnitude may correspond to a voltage value that can be sensed when the switching element IGBT is likely to be destroyed or destroyed by the driving voltage, or when safety can be ensured.

The comparison unit 13b compares the magnitude of the sensed voltage value with the reference magnitude, and if the magnitude of the sensed voltage value is less than the reference magnitude, applies the comparison result or comparison signal corresponding thereto to the output unit 13b. Thus, the output portion 13c allows the on signal from the input portion 13a to be applied to the switching element portion.

On the other hand, the comparator 13b compares the magnitude of the sensed voltage value with the reference magnitude, and when the magnitude of the sensed voltage value is greater than or equal to the reference magnitude, applies the comparison result or comparison signal corresponding thereto to the output unit 13c. . Accordingly, the output unit 13c receives the on signal from the input unit 13a, but applies an off signal to the switching element unit to block the current supplied by the driving voltage from being supplied to the resonance unit.

Accordingly, when the output unit 13c receives the OFF signal from the input unit 13a, the output unit 13c applies a control signal to the switching element unit through the output terminal O in accordance with the signal from the input unit 13a, and input unit 13a. In the case of receiving the signal from, the control signal is applied to the switching element in consideration of both the control signal from the input unit 13a and the comparison result from the comparison unit 13b. Through this process, the driving unit 13

Even when the on-signal is received from the microcomputer 15, the off-signal is applied to the switching element portion to directly control the actual on time of the switching element portion.

The retrigger portion 14 and the microcomputer 15 may be used components that are applied in the switching protection device of a general induction heating cooker. Accordingly, further description is omitted.

3 are operational graphs of a switching element (IGBT) protection device at stand-by of an induction heating cooker. (a) is an output signal of the microcomputer 15, (b) is an output signal of the driving unit 13, (c) is a voltage graph charged in the capacitor (C1) and sensed by the comparator 13b, ( d) is a graph of resonance voltage Vce of the switching element IGBT.

In FIG. 3, when the AC power source 11 is 220V and the induction heating cooker is in the standby state, the microcomputer 15 malfunctions and continuously applies a control signal (voltage level LOW) to the drive unit 13. The operation of the switching element protection device in the case is shown.

At time 0-t1, the microcomputer 15 applies an off control signal (voltage level HIGH) to the drive part 13 according to a standby state. As a result, the driver 13 applies an off signal (voltage level LOW) to the switching element portion, and the switching element IGBT of the switching element portion is turned off, so that no current is supplied to the resonant portion. Therefore, the resonant voltage Vce of the switching element IGBT is maintained at a constant value, and the comparator 13b does not apply the constant current to the capacitor unit 22, and the first and second current applying units 24, Since no current is applied through the capacitor 26, the capacitor C1 is not charged.

The time period t1 to t2 will be described. At time t1, the microcomputer 15 malfunctions, and applies an on control signal (voltage level LOW) to the driver 13. As a result, the driver 13 applies an ON signal (voltage level HIGH) to the switching element portion, the switching element IGBT of the switching element portion is turned on, and a current is supplied to the resonance portion. Thereafter, since a current flows in the resonator unit, a constant current is applied to the voltage sensing unit through the S terminal. Therefore, the switching element IGBT of the switching element portion is turned on so that a current flows in the resonant portion, and according to the magnitude of the driving voltage, through the first current applying portion 24 or the first current applying portion 24 and The current is applied to the capacitor unit 22 through the second current applying unit 26. In the on state of the switching element IGBT, as shown in FIG. 3D, the resonant voltage Vce is changed, the capacitor 22 is charged, and the comparator 13b of the driver 13 is timed. It can detect the voltage value increasing accordingly.

In the period (t2 or later), the comparison unit 13b of the driving unit 13 compares the reference voltage with the detected voltage value, and when the detected voltage value is equal to or greater than the reference voltage, the comparison result is output to the output unit 13c. Therefore, even if the output unit 13c continuously transmits the control signal LOW from the microcomputer 15, the output unit 13c applies the off signal LOW to the switching element unit so that the switching element IGBT is time t2. , To be off. Accordingly, the resonance voltage Vce is also rapidly attenuated after a certain time. Accordingly, the ON time (TURN ON time) of the switching device IGBT can be limited to protect the switching device IGBT from overcurrent and overresonant voltage.

4 are operational graphs of a switching device protection device at low voltage. 4 shows that when the AC power source 11 is low voltage (e.g., 180V) and the driving voltage accordingly becomes low,

The operation of the switching element protection device in the case where the microcomputer 15 malfunctions and continuously applies the on-control signal (voltage level LOW) to the driver 13 is shown.

The time 0 to t1 of FIG. 4 is the same as the corresponding time interval of FIG. 3, except that the resonance voltage Vce of (d) is slightly lowered.

The time period t1 to t2 will be described. At time t1, the microcomputer 15 malfunctions, and applies an on control signal (voltage level LOW) to the driver 13. As a result, the driver 13 applies an ON signal (voltage level HIGH) to the switching element portion, the switching element IGBT of the switching element portion is turned on, and a current is supplied to the resonance portion. Thereafter, since a current flows in the resonator unit, a constant current is applied to the voltage sensing unit through the S terminal. Therefore, since the switching element IGBT of the switching element part is turned on, current flows in the resonant part, and is low voltage according to the magnitude of the driving voltage (that is, when the driving voltage is greater than or equal to the first size and less than the second size). The current is applied to the capacitor unit 22 only through the one current applying unit 24. As shown in (d) of FIG. 4, the resonant voltage Vce is changed, the capacitor 22 is charged, and the comparator 13b of the driving unit 13 is in the ON state of the switching element IGBT. It can detect the voltage value increasing accordingly.

In the time t2 of the time t2 and later sections, the same operation as in the corresponding section of FIG. 3 is performed, thereby limiting the ON time (TURN ON time) of the switching element IGBT so that the switching elements (from the overcurrent and the over resonance voltage) IGBT) can be protected.

5 are operation graphs of the switching element protection device at high voltage.

Fig. 5 is a driving voltage diagram when the AC power supply 11 has a high voltage (for example, 250V).

The operation of the switching element protection device in the case where the microcomputer 15 malfunctions and continuously applies the on-control signal (voltage level LOW) to the drive unit 13 when it becomes high is shown. The time 0 to t1 of FIG. 5 is the same as the corresponding time interval of FIG. 3 except that the resonant voltage Vce of (d) is somewhat higher or equal.

The time period t1 to t2 will be described. At time t1, the microcomputer 15 malfunctions, and applies an on control signal (voltage level LOW) to the driver 13. As a result, the driver 13 applies an ON signal (voltage level HIGH) to the switching element portion, the switching element IGBT of the switching element portion is turned on, and a current is supplied to the resonance portion. Thereafter, since a current flows in the resonator unit, a constant current is applied to the voltage sensing unit through the S terminal. Therefore, since the switching element IGBT of the switching element portion is turned on, current flows in the resonant portion, and because the magnitude of the driving voltage is a high voltage (that is, when the driving voltage is greater than or equal to the second size), the first current applying portion 24 is applied. ) And the second current applying unit 26, current is applied to the capacitor unit 22.

As a result, the charge of the capacitor unit 22 becomes more rapid than that of the low voltage of FIG. 4, and thus, more quickly and accurately, in response to or in proportion to the magnitude of the AC power source 11 or the magnitude of the driving voltage. You can react. As shown in FIG. 5B, the on period of the switching element IGBT is significantly smaller than the on period of FIG. 4.

In the on state of the switching element IGBT, as shown in FIG. 5D, the resonant voltage Vce is changed, the capacitor 22 is charged, and the comparator 13b of the driver 13 is timed. It can detect the voltage value increasing accordingly.

In the time t2 of the time t2 and later sections, the same operation as in the corresponding section of FIG. 3 is performed, thereby limiting the ON time (TURN ON time) of the switching element IGBT so that the switching elements (from the overcurrent and the over resonance voltage) IGBT) can be protected.

6 are operational graphs of a switching device protection device during power supply distortion. By performing a cooking process or the like of the induction heating cooker, the operation of the switching element protection device will be described when distortion occurs in the driving voltage while the induction heating is being performed.

In the time period (0 to t1), the on signal and the off signal of the driving unit 13 are applied to the switching element unit in response to the on control signal and the off control signal from the microcomputer 15. That is, in this section, as can be seen in FIG. 6C, it means that the voltage value charged in the capacitor unit 22 is kept below the reference voltage.

Look at the time (t1 ~ t2) interval. A distorted driving voltage is applied near the time t1. Here, the driving voltage with distortion is a case where distortion occurs, for example, as shown in the waveform shown in FIG. Due to this distortion, when the microcomputer 15 applies the on control signal and the driving unit 13 switches the switching element IGBT to the on state, the charging speed (or charging degree) of the capacitor unit 22 is higher than before. Remarkably rapid progress is confirmed in (c). Accordingly, at time t2, as the voltage value charged in the capacitor unit 22 becomes equal to or greater than the reference voltage, the driving unit 13 receives the control signal from the microcomputer 15, but the switching element IGBT. To the OFF signal.

The on period of the switching element IGBT is reduced by the time period t2 to t3.

This protects the switching element (IGBT) from overcurrent and overresonant voltage.

Since the period t3 to t4 is a period in which the microcomputer 15 applies the off control signal to the driving unit 13, the driving unit 13 supplies the off signal regardless of the charged voltage value of the capacitor unit 22. Applied to the switching element portion.

In the period of time t4 to t5, a distorted driving voltage is applied even at time t4, and since the distortion degree is severe (that is, the driving voltage is higher), the charging speed of the capacitor unit 22 is increased. It is confirmed that it is faster than (t1 to t2). By the fast charging of the capacitor unit 22, the driving unit 13 applies the OFF signal to the switching element IGBT more quickly.

As can be seen in later time intervals, when a larger distortion voltage or power is applied, the capacitor unit 22 charges more quickly, such that the driver 13 is quickly turned off in response to or in proportion to the degree of distortion. Control is possible. This rapid control is possible because of the use of the current supply time due to the driving voltage applied to the resonator unit, and in addition to the first current applying unit 24, the second current applying unit 26 is provided to provide the magnitude of the driving voltage ( Corresponding to or proportional to the size of the AC power source 11, it is possible because of the configuration in which the time constant at the time of charging the capacitor unit 22 can be varied.

Hereinafter, the present invention has been described in detail based on the embodiments of the present invention and the accompanying drawings. However, the scope of the present invention is not limited by the following examples and drawings, and the scope of the present invention is defined in the contents of the claims below.

Will be limited only by

1 is a block diagram of a switching device protection device of the induction heating cooker according to the prior art.

2 is a block diagram of a switching device protection device of the induction heating cooker according to the present invention.

3 are operation graphs of the switching element protection device in the standby of the induction heating cooker.

4 are operational graphs of a switching device protection device at low voltage.

5 are operation graphs of the switching element protection device at high voltage.

6 are operational graphs of a switching device protection device during power supply distortion.

7 is an embodiment of a drive voltage with distortion.

Claims (7)

A resonator; A power supply unit receiving a commercial AC power supply and applying a driving voltage to the resonance unit; A switching element unit for supplying and blocking current to the resonator unit in accordance with the on signal and the off signal; A voltage sensing unit for applying a voltage value corresponding to a supply time of the driving voltage or a magnitude of the driving voltage when the current is supplied to the resonator unit; In response to the control signal from the microcomputer, an on signal and an off signal are applied to the switching element unit. When the microcomputer control signal is an on signal and the voltage value from the voltage sensing unit is greater than or equal to the reference magnitude, the off signal is applied to the switching element unit. A driving unit; In order to control the induction heating by the resonator, the switching element protection device of the induction heating cooker characterized in that the control signal consisting of a microcomputer to apply to the driving unit. The method of claim 1, When the control signal of the microcomputer is an off signal, the driver applies an off signal to the switching element independently of the voltage value from the voltage sensing unit, and the control signal of the microcomputer is the on signal and the voltage value from the voltage sensing unit is When less than the reference size, the switching element of the induction heating cooker characterized in that the on-signal is applied to the switching element portion Protection device. The method according to claim 1 or 2, When the driving voltage is greater than or equal to the first size, the voltage sensing unit is charged with a first current applying unit for applying current according to the magnitude of the driving voltage, a current from the first current applying unit, and a constant current from the driving unit. And a drive unit, wherein the driving unit receives a voltage value charged in the capacitor unit. The method of claim 3, The driving unit, when the control signal of the microcomputer is the ON signal, the switching element protection device for an induction heating cooker, characterized in that for applying a constant current to the capacitor. The method of claim 4, wherein The device for protecting the switching element of the induction heating cooker, characterized in that the first current applying unit has a first resistor connected in series with the capacitor unit. The method of claim 5, The voltage sensing unit is connected in parallel with the first current applying unit, and includes a second resistor, and when the driving voltage is greater than or equal to the second size greater than the first size, the second current applying unit for applying current according to the magnitude of the driving voltage. Of the induction heating cooker comprising Switching element protection device. The method of claim 4, wherein The driving unit is an input unit receiving a control signal from the microcomputer, a comparing unit operating according to the control signal from the microcomputer and comparing the voltage value from the voltage sensing unit with a reference magnitude, and a comparison result of the control signal from the input unit and the comparing unit. And an output unit for applying the on signal and the off signal to the switching element unit in accordance with the control signal from the input unit.

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