KR20000031058A - Method for controlling automatic cooking of microwave oven - Google Patents

Abstract

PURPOSE: A control method is provided to compensate the influence of surrounding environment to the voltage detection of a humidity sensor when continuously cooking food by employing the humidity sensor. CONSTITUTION: Automatic cooking of a microwave oven is controlled by the steps of: initializing a cooking chamber by driving a fan during a certain time; starting to drive a heating source and watching the voltage detected from a humidity sensor until the voltage reaches the highest point; timing the initial heating time until the voltage is changed as much as the set certain value after the highest point of the voltage is detected from the humidity sensor; and driving the heating source during the produced time after producing the additional heating time by multiplying the decided initial heating time by a constant depending on cooking materials.

Description

Auto cooking control method of microwave oven

The present invention relates to an automatic cooking control method of a microwave oven, and more particularly, to automatic cooking of a microwave oven, which can compensate for an error in cooking time that may be generated due to continuous heating in automatic cooking of a microwave oven using a humidity sensor. It relates to a cooking control method.

The microwave oven uses specific sensing means to interrupt heating when cooking. For example, a microwave oven using an infrared sensor detects a temperature inside a cooking chamber through the infrared sensor and controls a heating time based on the detected temperature. In addition, the microwave oven in which the humidity sensor is used, senses the humidity inside the cooking chamber through the humidity sensor, and controlled the heating time based on the detected humidity.

The following describes how to control the heating time in a microwave oven using a humidity sensor.

1 is an operating waveform diagram illustrating a method of determining a heating time based on humidity detected through a humidity sensor when auto-cooking a microwave oven according to the prior art.

As shown in FIG. 1, the auto cooking of the conventional microwave oven is supplied with power to the microwave oven, and only the fan is operated without driving the heating unit using the magnetron or the heater for a predetermined time T0. After the predetermined time T0 has elapsed, the initial heating time T1 is counted until a predetermined voltage dV is detected while the magnetron or the heater is driven.

The additional heating time is then calculated by multiplying the initial heating time T1 by a constant K set according to the type and quantity of food.

Therefore, the total heating time Tt is determined as a value obtained by adding the additional heating time T2 to the initial heating time T1.

By the way, the automatic cooking control of the conventional microwave oven outputs a different humidity change curve when the cooking is first performed after the power is supplied to the microwave and when the cooking is continuously performed. That is, as shown in FIG. 1, when the first operation is performed, the humidity change curve as shown in the P1 waveform of FIG. 1 is output, and when the continuous operation is performed, the humidity change curve as the P2 waveform of FIG. 1 is output.

This is because when automatic cooking using the humidity sensor is performed, the continuous cooking has an environment different from the humidity or temperature of the surrounding environment at the time of initial heating. Therefore, the time point at which the initial heating time T1 is determined according to the humidity change curve P1 or P2 is changed, and the additional heating time T2 calculated according to the initial heating time T1 also changes, so that the total heating time ( Tt). So even if you cook the same amount of food, the problem appears that the cooking time is different.

In particular, the conventional automatic cooking method tends to increase and decrease the infrared sensor detection voltage according to continuous cooking and the surrounding environment. In addition, as the initial heating time (T1) is counted from the start of the magnetron, the initial heating time (T1) becomes longer, and the total cooking time becomes longer, resulting in poor cooking.

Accordingly, an object of the present invention is to provide an automatic cooking control method for a microwave oven that can compensate for the influence of the surrounding environment on the voltage detection of the humidity sensor when continuous cooking using the humidity sensor.

1 is a humidity change curve calculated by automatic cooking of a microwave oven according to the prior art,

2 is a humidity change curve calculated by automatic cooking of a microwave oven according to the present invention,

3 is a block diagram for automatic cooking of a microwave oven according to the present invention;

4 is a flowchart illustrating an automatic cooking control method for a microwave oven according to the present invention;

Explanation of symbols on the main parts of the drawings

1: cooking chamber 3: motor

4: turntable 5: magnetron

6: fan 7: infrared sensor

8,9 vent hole 10 heater

11: food 13: detection unit

15: comparison unit 17: storage unit

19: calculator 21: coefficient storage unit

23 controller 25 up / down counter

27: drive circuit

Automatic cooking control method of the microwave oven according to the present invention for achieving the above object comprises the steps of: initializing the inside of the cooking chamber by driving a fan for a predetermined time; Starting driving of the heating source and monitoring the voltage value detected by the humidity sensor to reach a maximum point; Counting an initial heating time from a time point at which a peak voltage is detected from the humidity sensor to a predetermined amount of voltage change; And calculating the additional heating time by multiplying the determined constant according to the food to the determined initial heating time, and driving the heating source by the calculated time.

Hereinafter, an automatic cooking control method for a microwave oven according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows the humidity change curve according to the present invention. 2 shows the Y-axis not as the humidity but as the detected voltage value of the humidity sensor. Thus, when the humidity or temperature increases, the resistance value of the humidity sensor is reduced, and thus the detection voltage is also attenuated. The humidity conversion curve is shown as the detected voltage value.

The present invention is given a predetermined time T0 for adjusting the temperature and humidity of the cooking chamber of the microwave oven to a constant state. During the time T0, the magnetron does not operate, only the fan operates. In this way, the present invention minimizes the influence of the surrounding environment. The time T0 is included in the operating time of the microwave for cooking.

And the total heating time (Tt) according to the initial operation in the automatic cooking of the present invention is shown in the S1 humidity change curve shown in Figure 2, from the time the magnetron is driven until a certain amount of voltage change (dV) occurs Is determined by the sum of the initial heating time T1 and the additional heating time T2 calculated by multiplying the initial heating time T1 by the constant K.

And the total heating time (Tt) when the continuous cooking is performed, as shown in the S2 humidity change curve, the time required to reach the highest point (Ti), and the amount of voltage change (dV) from the Ti time point This is determined by the sum of the initial heating time T1 until generation and the additional heating time T2 calculated by multiplying the initial heating time T1 by the constant K.

Therefore, the required time Ta for cooking in the initial operation in the automatic cooking control of the present invention is determined as shown in Equation 1 below.

Ta = T0 + T1 + T2 ... (Equation 1)

And in the initial operation in the automatic cooking control of the present invention, the heating time (Tt) is determined as shown in Equation 2 below.

Tt = T1 + T2 ... (Equation 2)

In Formula 1 and Formula 2,

T0 = initialization time to adjust the temperature and humidity inside the cooking chamber to a constant state,

T1 = time from the start of heating until a certain amount of voltage change (dV) is detected,

The time determined by multiplying the predetermined value K by T2 = T1 is shown.

Next, therefore, the time Ta for cooking in the continuous operation in the automatic cooking control of the present invention is determined as shown in Equation 3 below.

Ta = T0 + Ti + T1 + T2 ... (Equation 3)

And the heating time (Tt) in the continuous operation in the automatic cooking control of the present invention is determined as shown in the following equation (4).

Tt = Ti + T1 + T2 ... (Equation 4)

In Equation 3 and 4,

T0 = initialization time to adjust the temperature and humidity inside the cooking chamber to a constant state,

Ti = time taken to reach peak after heating starts,

T1 = time from the time of Ti until a certain amount of voltage change (dV) is detected,

The time determined by multiplying the predetermined value K by T2 = T1 is shown.

In other words, the Ti time included in the continuous operation is almost reduced to zero when the influence of the ambient environment is small, so that the Ti time continues to decrease with little increase in voltage.

Next, Figure 3 shows a block diagram for automatic cooking of the microwave oven according to the present invention.

In the microwave oven of the present invention, the ventilation holes 8 and 9 are formed on the sidewalls of the cooking chamber 1, and the humidity sensor 7 is mounted to detect the humidity and temperature inside the cooking chamber 1 through the ventilation holes 9. do. The magnetron 5 as the first heating source is mounted on one side of the cooking chamber 1, and the heater 10 as the second heating source is mounted on the cooking chamber 1. And the fan 6 which controls the circulation of the air in the said cooking chamber 1 is mounted facing the said ventilation opening 9.

In addition, the microwave oven mounted the turntable driving motor 3 under the cooking chamber 1. The turntable 4 is installed inside the cooking chamber 1 of the microwave oven, and the turntable 4 is mounted on the shaft of the motor 3 to rotate with the rotation of the motor. The turntable 4 is placed with a load 11 containing the material to be cooked.

In addition, the present invention includes a sensing unit 13 for converting the humidity detected by the humidity sensor 7 into a voltage and outputting it, a current detection value output from the sensing unit 13 and a value stored in the storage unit 17; Comparing unit 15 and a storage unit 17 for temporarily storing the current output of the sensing unit 13 or any value compared by the comparing unit 15.

That is, the comparison unit 15 compares the current humidity detected by the humidity sensor 7 by using the value stored in the detection unit 13 as a reference signal.

In addition, the present invention is an operation unit 19 for performing a predetermined operation using the output of the comparison unit 15 or the storage unit 17 and the coefficient value stored in the coefficient storage unit 21, and the operation unit 19 Alternatively, the up / down counter 25 that counts based on the output of the comparator 15 and the heater 10 or the magnetron 5 or the fan 6 that are driven while the counter 25 is operated. The drive circuit 27 is included.

The up / down counter 25 counts the time required until the specific operation is completed from when the heating source starts to be driven under the control of the comparator 15, or zero from the value applied by the calculator 19. Count until

That is, the calculation unit 19 calculates the additional heating time T2 by multiplying the constant K by the initial heating time T1 after the initial heating time T1 is determined. The counter 25 counts the time until the highest point voltage is detected or counts the additional heating time T2 determined by the calculation unit 19. The coefficient storage unit 21 stores constant values suitable for calculating the additional heating time according to the amount or type of food.

Reference numeral 23 denotes a controller, which controls arithmetic operations of the arithmetic unit 19.

Next will be described in detail with reference to the accompanying drawings for the automatic cooking control method of the microwave oven according to the present invention having the above configuration.

4 is a flowchart illustrating an automatic cooking control method for a microwave oven according to the present invention.

When power is supplied to the microwave oven and a cooking start key is input, the controller 23 operates the fan 6 for a predetermined time T0 to minimize the influence of the surrounding environment. That is, the controller 23 outputs the operation time of the fan 6 to the counter 25 through the calculation unit 19. The counter 25 counts for an applied predetermined time (about 10 seconds) T0. The drive circuit 27 operates the fan 6 while the counter 25 is counted to adjust the humidity and temperature in the cooking chamber to a constant state (step 100).

Next, a preparation step for performing the next operation according to the initialization operation of all circuit parts is performed (step 102). Then, the heater 10 or the magnetron 5 is driven under the control of the driving circuit 27 (step 104). When the heating source in step 104 is driven, the drive circuit 27 drives the motor 3 to rotate the turntable 4.

After driving of the heating source in step 104 is started, it is determined whether a predetermined time (about 10 seconds) has elapsed (step 106), and the sensing unit 13 outputs a sensing voltage of the humidity sensor 7. (Step 108).

The sensing voltage of the humidity sensor 7 read in step 108 is temporarily stored in the storage unit 17. The sensing unit 13 continuously outputs the sensing voltage of the humidity sensor 7 at predetermined time intervals (about 8 seconds). The comparing unit 15 compares the current sensing voltage output from the sensing unit 13 with the voltage stored in the storage unit 17 to track the humidity change (step 110 and 112).

When the current sensing voltage is continuously smaller than the previous sensing voltage in the comparison process of step 112, the initial operation or the influence of the surrounding environment is less after the microwave power is supplied. That is, at this time, as in the S1 humidity change curve shown in FIG.

Therefore, in this case, the sensing voltage of the humidity sensor 7 detected at the beginning of heating when the magnetron starts to drive becomes the peak voltage Vref (step 114).

At this time, the counter 25 counts the initial heating time T1 after the heating of the magnetron starts (step 116).

The comparator 15 compares the initial peak voltage Vref and the current voltage Vo to monitor whether a certain amount of voltage change dV is generated (step 118). The counter 25 counts the initial heating time T1 while the comparison of the comparator 15 is continued.

When the detected voltage of the current humidity sensor 7 is compared with the initial peak voltage Vref in step 118, when a predetermined amount of voltage change dV occurs, the count of the initial heating time T1 is terminated. The controller 23 reads the count value set according to the amount and type of food to the determined initial heating time T1 from the coefficient storage unit 21, and multiplies it in the calculating unit 19 to further heat the time T2. Determine (step 120).

The additional heating time T2 determined in step 120 is applied to the counter 25 to control the heating operation of the drive circuit 27 during that time. The driving circuit 27 further performs heating of the food 11 during the additional heating time T2 (step 122), and terminates cooking when the additional heating time T2 ends.

On the other hand, when the current sensing voltage continues to be greater than the previous sensing voltage in the comparison process of step 112, the continuous cooking operation is performed after the power supply of the microwave oven is made. That is, at this time, the voltage is increased at the beginning of heating as shown in the S2 humidity change curve shown in FIG. 2.

Accordingly, the comparison unit 15 continuously repeats the process of determining the highest point while comparing the current sensed voltage with the previous sensed voltage at 8 second intervals (steps 108 through 112). The counter 25 counts the time Ti from the start of heating of the magnetron to reaching the highest point. The storage unit 17 takes a large value among the values to be compared and stores it, and outputs the stored value to the comparison unit 15 as a reference voltage at the next comparison.

When the highest voltage Vref is detected among the sensed voltages of the humidity sensor 7 by performing the above process (step 112), the count of the time Ti required to reach the highest point after the start of heating is also terminated. When the counting of the time Ti required to reach the highest point after the start of heating ends, the primary heating operation in which the magnetron 5 is driven under the control of the driving circuit 27 is also terminated. The peak voltage Vref is stored in the storage 17 (step 114).

Then, the counter 25 starts counting the initial heating time T1 from the time of Ti until a predetermined amount of voltage change dV is detected (step 116). As the counting of the initial heating time T1 of step 116 starts, a secondary heating operation is started in which the magnetron 5 is driven under the control of the driving circuit 27.

In this case, the storage unit 17 stores the highest voltage value Vref detected in the 114 step. The comparison unit 15 compares the peak voltage value Vref stored in the storage unit 17 with the detected voltage Vo of the current humidity sensor 7 to monitor whether a predetermined amount of voltage change dV is generated. (Step 118). Under the control of the comparison unit 15, the counter 25 counts the time required until a predetermined amount of voltage change dV is generated.

After comparing the peak voltage Vref and the current voltage Vo in the comparison unit 15, when a predetermined amount of voltage change dV is generated (step 118), the count 25 is the initial heating time T1. ) Count ends. At the same time as the initial heating time T1 is terminated in the counter 25, the secondary heating operation in which the magnetron 5 is driven under the control of the driving circuit 27 is also terminated.

The controller 23 then controls the calculation of the additional heating time T2. That is, the coefficient storage unit 21 outputs a predetermined coefficient K according to the amount and type of food. The calculating unit 19 multiplies the coefficient K by the initial heating time T1 to determine the additional heating time T2 (step 120).

The additional heating time T2 determined in step 120 is applied to the counter 25. The counter 25 counts until the applied additional heating time T2 becomes zero. While the counter 25 is being counted, a third heating operation of the magnetron 5 is performed under the control of the driving circuit 27 (step 122). At the counter 25, the counting operation of the additional heating time T2 is completed and the heating operation of the magnetron 5 is finished, and the cooking is finished.

As described above, the present invention provides an automatic cooking control method capable of realizing optimal cooking even in continuous cooking or changes in the surrounding environment (humidity and temperature). When the continuous cooking in the conventional automatic cooking control, the initial heating time (T1) is counted from the start time of the magnetron has a problem that the initial heating time (T1) is long, the entire cooking time is long. Therefore, in the present invention, when the voltage increases and decreases to eliminate such an error, the time to the highest point is determined as Ti, and the initial heating time T1 is counted from the time Ti at which the highest voltage is detected. Therefore, in this case, the time Ti does not affect the determination of the additional heating time T2 and is included only in the total heating time so that the total heating time is independent of the type of sensor voltage change (influence of the ambient environment). Minimize the error to achieve the best cooking.

Claims (1)

Initializing the inside of the cooking chamber by driving the pan for a predetermined time; Starting driving of the heating source and monitoring the voltage value detected by the humidity sensor to reach a maximum point; Counting an initial heating time from a time point at which a peak voltage is detected from the humidity sensor to a predetermined amount of voltage change; And calculating a further heating time by multiplying the determined constant according to the food to the determined initial heating time, and driving the heating source by the calculated time.