KR0182524B1 - Power control apparatus and control method for complex cooker - Google Patents

Abstract

The present invention relates to a power control device for a composite cooker, and in particular, a power control device for a composite cooker capable of stably supplying power consumption input by detecting a change in voltage of a driving means and a current change of a load according to temperature and time; A power control method, comprising: a microcomputer, drive means for receiving a control signal from the microcomputer and outputting a drive signal for driving a cooking means, and detecting a drive voltage of the drive means to provide the microcomputer to the microcomputer. A voltage detecting means for outputting, an input current detecting means for detecting an amount of change of current input to a load, and outputting it to the microcomputer, and a temperature for detecting a changing heating coil temperature and humidity of the cooking means and outputting it to the microcomputer Characterized in that the sensing means and the humidity sensing means.

Description

Power control device for multicooker and its power control method

1 is a control block diagram of a power control apparatus for a composite cooker according to an embodiment of the present invention.

2 is a detailed circuit diagram of a power control device for a composite cooker according to an embodiment of the present invention.

3A and 3B are flowcharts showing the power control operation procedure of the present invention.

* Explanation of symbols for main parts of the drawings

10: key input means 20: microcomputer

30: drive means 40: voltage detection means

50: AC power input means 60: input current detection means

70: humidity sensing means 80: temperature sensing means

90: rectification means 100: cooking means

101: induction heating means 102: dielectric heating means

The present invention relates to a complex cooker, and in particular, a power control device for a complex cooker capable of stably controlling the output power of the cooker by detecting the amount of change in the voltage and load of the driving means that changes with temperature and time, and its It relates to a power control method.

In general, the conventional power control method of the cooker compares the reference voltage and the amount of change of current detected at the power input terminal to cut off the power supply of the cooker during overload and to drive the cooker until the reference voltage rises in normal operation. By controlling the output voltage.

However, in this method, in controlling the output voltage of the cooker, since the output voltage is adjusted by using the driving characteristics of components such as comparators, operational amplifiers, resistors, and capacitors, the configuration of the control circuit is complicated and the manufacturing cost is high. As well as being raised, there is a problem that it is difficult to maintain a stable cooking state because it is difficult to control the output of the cooker due to the output error of each component.

Therefore, the present invention has been made to solve the conventional problems as described above, an object of the present invention by using a microcomputer and the input current detection means detects the amount of current flowing through the load to stabilize the output power of the cooker The present invention provides a power control apparatus and a power control method for a composite cooker that can be controlled and not only maintain a stable cooking state, but also have a simple configuration and a low manufacturing cost.

Another object of the present invention is to detect the voltage flowing through the switching element (transistor) using the voltage detecting means to stably control the output power of the multi-cooker to prevent destruction of the switching element and to prevent the temperature rise of the device The present invention provides a power control apparatus and a power control method of the multi-cooker which can not only ensure the safety of the device but also improve the cooking efficiency.

In order to achieve the above object, the power control apparatus for a composite cooker according to the present invention includes a microcomputer, drive means for outputting a drive signal for driving a cooking means by receiving a control signal from the microcomputer, A voltage detecting means for detecting a driving voltage of the driving means and outputting it to the microcomputer, an input current detecting means for detecting a change amount of current input to a load and outputting it to the microcomputer, and a heating coil of the cooking means Characterized in that it consists of a temperature sensing means and a humidity sensing means for sensing the temperature and humidity and output to the microcomputer.

In addition, the power control method of the multi-cooker according to the present invention is the reference voltage setting step of setting the output voltage reference value (Vs) to obtain the optimum cooking efficiency according to the key signal selected by the user, and in the reference voltage setting step The driving voltage maximum value Vm and the driving voltage Vce of the switching element for controlling the driving of the cooking means are compared, and the output voltage reference value Vs and the changeable input current value of the power input terminal in the reference voltage setting step are compared. (Vi), an output voltage compensation step for compensating the output voltage reference value Vs and the output voltage compensation step by comparing the heating coil temperature value Vt of the cooking means and the humidity value Vh in the cooking chamber, respectively; And a cooking discrimination step for determining whether cooking is performed while comparing the time T for maintaining the humidity value Vh at and the reference humidity holding time Ts preset in the microcomputer. It shall be.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 2, the power control device of the composite cooker is a key input means 10 provided with a plurality of function keys to set the operation start signal and the selection signal of the composite cooker, and the key input Microcomputer 20 for receiving the key signal from the means 10 to control the overall operation of the multi-cooker, and drive means 30 for receiving the control signal from the microcomputer 20 to drive the cooking means 100. ), From the voltage detecting means 40 for detecting the driving voltage of the driving means 30 and outputting it to the microcomputer 20, from the AC power input means 50 and the AC power input means 50. Input current detecting means 60 for detecting a change amount of current input to a load by receiving a commercial alternating voltage and outputting the detected change amount of current to the microcomputer 20; Humidity sensing means 70 for outputting to the furnace computer 20, the temperature sensing means 80 for sensing the heating coil temperature of the cooking means to be described later to output to the microcomputer 20, and the AC power input Rectification means (90) for receiving a commercial AC voltage from the means (50) and full-wave rectifying with DC, and a drive signal output from the drive means (30) at the same time as receiving the DC voltage output from the rectification means (90). Received is composed of cooking means 100 for heating the food in the cooking chamber.

In FIG. 3, the driving means 30 includes a photocoupler PC which is turned on to operate the cooking means 100 when the control signal output from the output terminal O1 of the microcomputer 20 is low. The transistor TR1 is turned on to receive the voltage Vcc 'applied from the outside when the photocoupler PC is turned on through the resistors R2 and R3 to operate the cooking means 100, and the transistor TR1. The protection diode D1 connected in parallel to the transistor TR1 to bypass the counter electromotive force generated during turn-off of the transistor and to protect the transistor TR1, and the transistor TR1 when the photocoupler PC is turned off. For protection connected in parallel to transistor TR2 to bypass the transistor TR2 turned on to discharge the charge charged therein and back electromotive force generated when the transistor TR2 is turned off to protect the transistor TR2. Composed of diode (D2) have.

In addition, the transistor TR2 has an emitter terminal connected to the base terminal of the transistor TR1, the resistor R1 is connected to a voltage Vcc applied from one side to the outside, and the other side of the photocoupler PC. Is connected to an anode terminal of a light emitting diode (LED), and a resistor (R2) is connected to a voltage (Vcc ') applied from one side to the outside, and the other side is a collector of the phototransistor (PT) of the photocoupler (PC). The resistor R3 is connected to the terminal, one side of which is connected to the emitter terminal of the phototransistor PT, and the other side of which is connected to the base terminal of the transistor TR2.

A resistor R4 is connected to the base and the emitter terminal of the transistor TR1 to maintain a constant current flowing through the base of the transistor TR1, and the transistor TR2 is connected to the base and collector terminal of the transistor TR2. The resistor R5 is connected to keep the current flowing through the base constant.

The voltage detecting unit 40 receives a driving voltage from the driving unit 30 through a resistor R6 and filters a DC component included in the driving voltage, and at the capacitor C1. A diode D3 connected in series with the capacitor C1 to receive the filtered driving voltage, and a smoothing capacitor C2 for filtering the pulsation component included in the voltage half-wave rectified by the diode D3; A zener diode ZD connected in parallel to the smoothing capacitor C2 so as to receive a half-wave rectified voltage from the diode D3 and bypass only a voltage equal to or greater than a breakdown voltage of a predetermined level, and from the zener diode ZD. A constant voltage is received at the inverting terminal (-) and at the same time the reference voltage (Vref) from the reference voltage generator 41 receives the non-inverting terminal (+) to compare the drive means 30 to drive control The comparator COM1 outputs to the input terminals A / D2 of the microcomputer 20.

One end of the resistor R6 is connected to the collector terminal of the transistor TR1 of the driving means 30, the other end thereof is connected to one side of the capacitor C1, and the one side of the smoothing capacitor C2 is It is connected to the cathode terminal of the diode D3 and the other side is grounded.

In addition, the input current detecting means 60 receives a commercial AC voltage from the AC power input means 50 and detects by the current transformer CT and the current transformer CT a change amount of the current input to the load. The resistor R8 connected in parallel with the secondary side of the current transformer CT to convert the fluctuation amount of the converted current into a voltage fluctuation and the noise component included in the voltage signal converted by the resistor R8. A capacitor C3 connected in parallel to R8, a bridge rectifier 61 for receiving a voltage signal filtered by the capacitor C3, and performing a full-wave rectification by DC; and a DC voltage from the bridge rectifier 61. It consists of a resistor (R9) and a capacitor (C4) connected in parallel to the output of the bridge rectifier (61) to filter out the pulsating components present.

In addition, in the drawing, the temperature detecting means 80 is a temperature sensor 81 for sensing the temperature of the heating coil (L1) of the cooking means 100, the temperature sensor 81 and the resistor (R10) The capacitor C4 connected in parallel to the resistor R10 and the temperature sensing signal filtered by the capacitor C4 are inputted from the inverting terminal (−) to filter the ripple component included in the divided temperature sensing signal. At the same time, the reference voltage Vref from the reference voltage generator 81 is received at the non-inverting terminal (+), and the drive terminal 30 is compared with the input terminal A / of the microcomputer 20. Comparator (COM2) output to the D5), one side of the resistor (R10) is connected in series to one side of the temperature sensor 81, the other side is grounded.

The rectifying means 90 is a bridge rectifier 91 for receiving a commercial AC input voltage from the AC power input means 50 and full-wave rectifying with DC, and a pulse current included in the DC voltage from the bridge rectifier 91. It is composed of a smoothing capacitor C5 having one side connected in parallel to the output terminal of the bridge rectifier 91 and the other side grounded to filter the components.

In addition, the cooking means 100 receives the DC voltage from the rectifying means 90 and at the same time receives a drive signal from the driving means 30, induction heating means 101 for induction heating of food in the cooking chamber. And a dielectric heating means 102 for receiving a DC signal from the rectifying means 90 and receiving a driving signal from the driving means 30 to dielectrically heat food in the cooking chamber.

The induction heating means 101 receives a DC voltage from the rectifying means 90 and generates a heating coil L1 for generating an eddy current in the load and the container, and receives a DC voltage from the rectifying means 90 to charge and discharge the same. And a resonance capacitor C7 connected in parallel to the heating coil L1 to form a voltage source for driving the induction heating means 101.

The dielectric heating means 102 receives a driving contact signal from a relay driving means (not shown) from the relay RL and when the relay RL is induced to the relay contact NO, the rectifying means 90. Receiving capacitor (C8) and the voltage charged in the resonant capacitor (C8) to form a voltage source for driving the dielectric heating means (102) while receiving and charging the DC voltage from the primary side The magnetron converts the high voltage into a high voltage transformer 103 to be induced on the secondary side, and the AC power applied to the primary winding of the high voltage transformer 103 is induced in the secondary winding to oscillate ultra-high frequency so that cooking can be performed. 104 and a back voltage rectifying circuit 105 which receives the AC power induced in the secondary winding of the high voltage transformer 103 and rectifies the back voltage of the high voltage and the low current to output the magnetron 104. It is.

The back pressure rectifying circuit 105 of the dielectric heating means 102 includes a capacitor C9 for charging the induced voltage in the secondary winding of the high voltage transformer 103 and a voltage charged in the capacitor C9 for a high voltage and It consists of diodes D4 and D5 which are rectified with a low current double voltage and output to the magnetron 104.

Hereinafter, the operation and effect of the power control device of the composite cooker configured as described above will be described.

First, the input voltage of the commercial AC power supplied from the AC power source input means 50 of the composite cooker is full-wave rectified by the full-wave rectifier 91 into the DC voltage and included in the full-wave rectified DC voltage. If the filter is applied at (C5) to the constant voltage means (not shown), the constant voltage means converts it into a constant voltage necessary for the operation of the microcomputer 20 and applies it to the microcomputer 20.

Then, the key cooker 10 outputs an operation selection signal of an output level desired by the user to the input terminal A / D1 of the microcomputer 20, so that the composite cooker starts operation as described below. do.

First, in the normal operation of the composite cooker, the microcomputer 20 applies a low level control signal to the cathode terminal of the light emitting diode LED of the photocoupler PC through the output terminal O1. The light emitting diode LED of the photocoupler PC receives a voltage Vcc applied from the outside from the anode terminal through a resistor R1 and turns on the phototransistor PT while the light emitting diode LED is lit. Let's do it.

When the phototransistor PT is turned on, the transistor TR1 is turned on by applying an external voltage Vcc 'to the base terminals of the transistors TR1 and TR2 through the resistors R2 and R3. TR2 is turned off.

When the transistor TR1 is turned on, the induction heating means 101 of the cooking means 100 receives a DC voltage from the rectifying means 90 from the resonant capacitor C7 to charge and discharge the voltage source for driving the load. In the heating coil (L1) to form an eddy current in the load and the container to induction heating the food in the cooking chamber.

When the relay RL of the cooking means 100 receives a driving contact signal from a relay driving means (not shown) when the transistor TR1 is turned on, the relay RL is connected to the relay contact NO. DC voltage from the rectifying means 90 is applied to the dielectric heating means 102, the dielectric heating means 102 receives the DC voltage from the rectifying means 90 in the resonant capacitor (C8) and charge and While discharging, the high voltage transformer 103 converts the high voltage into the high voltage through the high voltage transformer 103.

Therefore, the magnetron 104 oscillates ultra-high frequency to dielectrically heat food in the cooking chamber.

As described above, when cooking is started by the induction heating means 101 or the dielectric heating means 102, voltage values such as voltage, current, temperature, humidity, and the like of the multicooker change as time passes.

Accordingly, in the voltage detecting means 40, the resonance voltage Vce generated between the collector of the transistor TR1 and the emitter terminal when the transistor TR1 of the driving means 30 is turned on includes the resistor R6 and the capacitor. After filtering by (C1), half-wave rectification is performed at the diode D3 by direct current.

If the voltage half-wave rectified by the diode D3 is lower than the voltage Vzd set in the zener diode ZD, the rectified voltage is applied to the inverting terminal (-) of the comparator COM1 as it is, and the zener diode ZD is applied. When the voltage Vzd is higher than the voltage Vzd set, only a voltage equal to or greater than the breakdown voltage of a predetermined level is applied to the inverting terminal (-) of the comparator COM1.

Accordingly, the comparator COM1 compares the driving voltage applied to the inverting terminal (-) with the reference voltage Vref of the non-inverting terminal (+). In the normal operation of the composite cooker, the inversion of the comparator COM1 is performed. Since the driving voltage Vce applied to the terminal (-) is smaller than the reference voltage Vref of the reference voltage generator 41, a high level output signal is applied to the input terminals A / D2 of the microcomputer 20. do.

Accordingly, the microcomputer 20 outputs a low-level state signal to the driving means 30 through the output terminal O1 to maintain the turn-on state of the transistor TR1 to continue the cooking operation.

On the other hand, when the cooking means 100 operates, the input voltage and input current of the AC power input means 10 increase, or the humidity of the cooking chamber increases and the temperature of the induction coil L1 increases the emission of the transistor TR1. When the composite cooker is overloaded, the resonance voltage Vce applied to the inverting terminal (-) of the comparator COM1 is the reference voltage generator 41. Since the output signal is higher than the reference voltage Vref, the low level output signal is applied to the input terminals A / D2 of the microcomputer 20.

Accordingly, the microcomputer 20 stops the cooking operation by outputting a high level status signal to the driving means 30 through the output terminal O1 and turning off the transistor TR1.

In the input current detecting means 60, the current variation input to the load is detected by the current transformer CT, and the detected current variation is converted from the resistor R8 to the voltage variation to input the terminal of the microcomputer 20. When outputting to A / D1, in the microcomputer 20, the output voltage reference value Vs set by the user by the key input means 10 and the input current detection value from the input current detection means 60 ( Compare Vi).

As a result of the comparison, when the input current detection value Vi is smaller than the output voltage reference value Vs, the microcomputer 20 outputs a low level state signal to the driving means 30 through the output terminal O1. The cooking operation is continued by turning on the transistor TR1.

On the other hand, if the input current detection value Vi is greater than the output voltage reference value Vs, the microcomputer 20 outputs a high level status signal to the driving means 30 through the output terminal O1 to the transistor. The cooking operation is stopped by turning off TR1.

In addition, in the drawing, the humidity detecting means 70 detects the humidity of the food in the cooking chamber and outputs it to the input terminals A / D4 of the microcomputer 20. In the microcomputer 20, the key input means ( In step 10), the output voltage reference value Vs set by the user is compared with the humidity value Vh sensed by the humidity sensing means 70.

As a result of the comparison, when the current humidity value Vh is smaller than the output voltage reference value Vs, the complex humidity cooker compensates the output voltage reference value Vs by subtracting the current humidity value Vh from the output voltage reference value Vs. Keep the output power of constant.

In addition, the temperature detecting unit 80 detects a change in the heating coil temperature of the cooking unit 100 and outputs the detected temperature value Vt to the input terminals A / D5 of the microcomputer 20. The microcomputer 20 compares the output voltage reference value Vs set by the user by the key input means 10 with the present temperature value Vt of the temperature sensing means 80.

As a result of the comparison, if the present temperature value Vt is not equal to the output voltage reference value Vs, the present temperature value Vt is added to or subtracted from the output voltage reference value Vs to compensate for the output voltage reference value Vs. Keep the output power of the cooker constant.

Next, the power control method of the composite cooker according to the present invention will be described in detail with reference to FIG.

3A and 3B are flowcharts showing the power control operation procedure of the present invention.

First, the input voltage of the commercial AC power supplied from the AC power input means 10 of the composite cooker is full-wave rectified to DC voltage in the full-wave rectifier 91, and smoothes the pulse current component included in the full-wave rectified DC voltage. Filter at (C5) and apply to the constant voltage means not shown. Accordingly, the constant voltage means receives the DC voltage from the rectifying means, converts it into a constant voltage necessary for the operation of the microcomputer 20, and applies the DC voltage to the microcomputer 20.

Then, the key cooker 10 applies the operation selection signal of the output level desired by the user to the input terminal A / D1 of the microcomputer 20, so that the composite cooker starts operation as described below. .

At this time, in order to control the output voltage (power) of the multicooker, in step S1, the multicooker is initialized according to the power control function, and in step S2, the key input signal of the output level desired by the user by the key input means 10. Select and output to the microcomputer 20.

Subsequently, in step S3, the resonance voltage maximum value Vm, the output voltage reference value Vs, the coil saturation temperature value Vl, and the reference of the driving means 30 in the microcomputer 20 in accordance with the output value selected in step S2. The humidity holding time Ts is set, and in step S4, the voltage detecting means 40 detects the resonance voltage Vce generated when the transistor TR1 of the driving means 30 is turned on to detect the microcomputer 20. Output to

In step S5, it is determined whether the resonance voltage Vce detected in the step S4 is smaller than the driving voltage maximum value Vm in the step S3, and the resonance voltage Vce determined by the microcomputer 20 is determined. Is smaller than the driving voltage maximum value Vm (Yes), the amount of change of the current input to the load by the input current detecting means 60 is detected and output to the microcomputer 20 in step S6.

Thereafter, in step S7, the microcomputer 20 determines whether the input current value Vi detected in the step S6 is larger than the output voltage reference value Vs in the step S3, and determines the microcomputer ( If the input current value Vi determined in step 20) is not greater than the output voltage reference value Vs (No), the heating coil temperature of the cooking means 100 is changed by the temperature sensing means 80 in step S8. Is detected and output to the microcomputer 20.

Subsequently, in step S9, it is determined whether or not the coil current temperature value Vt sensed by the temperature sensing means 80 is smaller than the output voltage reference value Vs in step S3. If the determined coil current temperature value Vt is not smaller than the output voltage reference value Vs (No), the coil current temperature value Vt determined by the microcomputer 20 in step S10 is the output voltage reference value ( Is greater than Vs).

As a result of the determination in step S10, when the coil current temperature value Vt determined by the microcomputer 20 is larger than the output voltage reference value Vs (Yes), the output voltage in step S10 in step S11. The output voltage reference value Vs is compensated by adding a reference value Vs and a coil current temperature value Vt.

In step S12, the humidity sensing unit 70 senses the humidity in the cooking chamber and outputs it to the microcomputer 20. In step S13, the current humidity value detected by the humidity sensing unit 70 in step S12. It is determined whether (Vh) is smaller than the output voltage reference value Vs compensated in step S11.

As a result of the determination in step S13, when the current humidity value Vh determined by the microcomputer 20 is smaller than the compensated output voltage reference value Vs (Yes), the compensation in step S11 is performed in step S14. The output humidity reference value Vs is compensated by subtracting the present humidity value Vh from the output voltage reference value Vs, and in step S15 the current humidity value Vh is maintained by the microcomputer 20 in step S12. The time T to be detected is detected.

Next, in step S16, it is determined whether or not the reference humidity holding time Ts in the step S3 is greater than the current humidity holding time T detected in the step S15, and the reference humidity determined by the microcomputer 20 is determined. If the holding time Ts is not greater than the current humidity holding time T (No), the microcomputer 20 determines whether or not the cooking function is completed in step S17.

As a result of the discrimination in step S17, when the cooking function determined in the microcomputer 20 is completed (Yes), the process proceeds to step S18 and the microcomputer 20 outputs a high level control signal to the driving means 30. By turning off the transistor TR1, the cooking operation is terminated while the power supply is cut off.

On the other hand, when the coil present temperature value Vt determined by the microcomputer 20 is smaller than the output voltage reference value Vs (Yes) as a result of the discrimination in step S9, the output in step S9 in step S19. The output current voltage reference value Vs is compensated by subtracting the coil current temperature value Vt from the voltage reference value Vs, and in step S20 the output voltage reference value Vs compensated in step S19 is the coil saturation in step S3. It is judged whether or not it is larger than the temperature value Vl.

As a result of the discrimination in step S20, when the output voltage reference value Vs compensated in step S19 is not greater than the coil saturation temperature value Vl (No), the operation of step S12 or less is repeated in step S12, As a result of the discrimination in step S17, when the cooking function determined by the microcomputer 20 is not completed (No), the process proceeds to step S21 and returns to step S4 while maintaining the current output voltage reference value Vs. The operation of step S4 or less is repeated.

When the resonant voltage Vce determined by the microcomputer 20 is not smaller than the resonant voltage maximum value Vm (No) as a result of the discrimination in step S5, the flow goes to step S18 to cut off the power supply. The cooking operation ends.

On the other hand, when the determination result in step S7 indicates that the input current value Vi determined by the microcomputer 20 is larger than the output voltage reference value Vs (Yes), the process proceeds to step S18 to cut off the power. When the operation is terminated and the determination result in step S20 indicates that the output voltage reference value Vs compensated in step S19 is greater than the coil saturation temperature value Vl (Yes), the flow goes to step S18 to cut off the power. The cooking operation ends.

If the coil current temperature value Vt determined by the microcomputer 20 is not greater than the output voltage reference value Vs (No), the determination proceeds to step S12 and the step S12 or less. If the present humidity value Vh determined by the microcomputer 20 is not smaller than the output voltage reference value Vs (No), the process proceeds to step S15. The operation below S15 is repeated.

On the other hand, if the reference humidity holding time Ts determined by the microcomputer 20 is greater than the current humidity holding time T (Yes) as a result of the determination in step S16, the process returns to step S4 and step S4. The following operation is repeated.

According to the power control device and the power control method of the composite cooker according to the present invention as described above, by using a microcomputer and the input current detection means to detect the amount of current flowing through the load stabilizes the output power of the cooker In addition to maintaining a stable cooking state, it has an excellent effect that the configuration is simple and the manufacturing cost is low, and the output power of the complex cooker is detected by detecting the voltage flowing through the switching element using the voltage detecting means. Since the control can be stably controlled, it is possible to prevent the destruction of the switching element and the temperature rise of the device, thereby ensuring the safety of the cooker and improving the cooking efficiency.

Claims (9)

In a multi-cooker, a microcomputer, a driving means for receiving a control signal from the microcomputer and driving a cooking means, a voltage detecting means for detecting a driving voltage of the driving means and outputting the driving voltage to the microcomputer, and inputting it to a load Input current detection means for detecting the amount of change of the current to be output to the microcomputer, temperature sensing means for detecting the heating coil temperature and humidity of the cooking means to output to the microcomputer and humidity sensing means Power control device for a composite cooker. According to claim 1, wherein the driving means is a photocoupler (PC) that is turned on to operate the cooking means when the control signal output from the microcomputer is low, and is applied from the outside when the photocoupler (PC) is turned on The transistor TR1 bypasses the transistor TR1 turned on to receive the voltage Vcc 'through the resistors R2 and R3 and to operate the cooking means, and the counter electromotive force generated when the transistor TR1 is turned off. A protection diode D1 connected in parallel to the transistor TR1 to protect the transistor, a transistor TR2 turned on to discharge the charge charged in the transistor TR1 when the photocoupler PC is turned off; And a protection diode D2 connected in parallel to the transistor TR2 to bypass the counter electromotive force generated when the transistor TR2 is turned off to protect the transistor TR2. Power control apparatus for a composite cooking to. According to claim 1, wherein the voltage detecting means is a capacitor (C1) for filtering the DC component included in the drive voltage of the drive means, and the capacitor (C1) to receive the half-wave rectification by receiving the drive voltage filtered by the capacitor (C1) The diode D3 connected in series with C1), the smoothing capacitor C2 for filtering the pulsation component included in the voltage half-wave rectified in the diode D3, and the voltage half-wave rectified in the diode D3. A zener diode ZD connected in parallel to the smoothing capacitor C2 to bypass only a voltage higher than a breakdown voltage of a predetermined level, and a constant voltage and a reference voltage from the zener diode ZD for pulsating control of the driving means. A power control device for a composite cooker, characterized by comprising a comparator (COM1) for comparing the reference voltage (Vref) of the generator. 2. The current transformer according to claim 1, wherein the input current detecting means comprises: a current transformer CT that receives a commercial AC voltage from an AC power input means and detects a change amount of a current input to a load, and a current of the current detected by the current transformer CT. A resistor R8 connected in parallel with the secondary side of the current transformer CT to convert the amount of variation into a voltage variation, and the resistor R8 to filter noise components included in the voltage signal converted by the resistor R8. A capacitor C3 connected in parallel to the capacitor C; And a resistor (C9) and a resistor (R9) connected in parallel to the output terminal of the multi-cooker. The method of claim 1, wherein the temperature sensing means to filter the ripple component contained in the temperature sensor for detecting the heating coil temperature of the cooking means, and the temperature sensing signal divided by the temperature sensor and the resistor (R10). The capacitor C4 connected in parallel to the resistor R10 and the temperature sensing signal filtered by the capacitor C4 and the reference voltage Vref of the reference voltage generator 81 to drive control of the driving means are compared. Power control device for a composite cooker, characterized in that composed of a comparator (COM2). A reference voltage setting step of setting an output voltage reference value Vs so as to obtain an optimum cooking efficiency according to the key signal selected by the user, a maximum driving voltage value Vm at the reference voltage setting step, and driving of the cooking means; Comparing the driving voltage Vce of the switching element for controlling the voltage, output voltage reference value Vs at the reference voltage setting step, changing input current value Vi at the power input terminal, and changing heating coil temperature of the cooking means. An output voltage compensation step for compensating the output voltage reference value Vs and a time for maintaining the humidity value Vh in the output voltage compensation step while comparing the value Vt and the humidity value Vh in the cooking chamber, respectively. And a cooking discrimination step of determining whether cooking is performed while comparing T) and the reference humidity holding time (Ts) preset in the microcomputer. 7. The cooking operation according to claim 6, wherein the cooking operation is stopped when the drive voltage value Vce detected by the voltage detection means in the output voltage compensation step is not smaller than the drive voltage maximum value Vm in the reference voltage setting step. Power control method for a composite cooker characterized in that. 7. The cooking operation according to claim 6, wherein the cooking operation is stopped when the input current value Vi detected by the input current detection means in the output voltage compensation step is larger than the output voltage reference value Vs in the reference voltage setting step. Power control method for a composite cooker, characterized in that. The method of claim 6, wherein when the current humidity holding time T determined in the cooking discrimination step is larger than the reference humidity holding time Ts in the reference voltage setting step, the output voltage compensation step is returned. Power control method of a composite cooker.