KR100341164B1 - Calibration method of sensing voltage in sensor utilizing standard load - Google Patents

Abstract

The present invention relates to a method of calibrating a detection voltage of a sensor using a reference load, and in a microwave oven in which a control unit recognizes a heating state of food based on a detection voltage detected by a microwave detection sensor, an inspector uses a standard load. Detects a detected voltage value by the sensor before shipment, calculates a correction coefficient required to calibrate the detected detection voltage value to a preset reference voltage value, and stores the calculated correction coefficient in an EEPROM. When the actual food is cooked, the control unit recognizes the heating state of the food using the stored calibration coefficients so that the control unit detects the actual value of the microwave oven according to the detection voltage value which is differently detected due to the setability of the microwave oven and the deviation of the parts. The error rate of the microwave is reduced by preventing the misunderstanding of the heating state of the food.

Description

Calibration method of sensing voltage in sensor utilizing standard load

The present invention relates to a method for calibrating a detection voltage of a sensor using a reference load, and to calibrate a detection voltage of a sensor that detects a heating state of food as a voltage value to be a preset reference voltage for each product of a microwave oven.

In general, a microwave oven is configured such that molecules of a food are subjected to molecular motion by a high-frequency microwave of 2450 MHz generated by magnetron oscillation, and cooking is performed by frictional heat caused by the molecular motion.

In order to cook the food efficiently, it is required to analyze the heating state of the food during cooking and to control the cooking operation based on the cooking. In a conventional microwave oven, a method of detecting microwaves reflected in a cooking chamber is used as a method for determining a heating state of food, and a sensor is used as a means for detecting the microwaves. The sensor receives and rectifies the microwaves reflected by the cooking chamber through an antenna, and transmits an output signal of the sensor to a controller. The controller recognizes the heating state of the food based on the output signal of the transmitted sensor.

However, according to the prior art, due to assembly errors during product manufacturing or deviation of parts, the control unit receives a detection voltage different from the actual load from the sensor, and thus incorrectly recognizes the heating state of the food, and thus could not perform good cooking. . As a result, the error rate of the microwave oven is increased, thereby reducing the reliability of the product.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to correct a detection voltage of a sensor for each product of a microwave oven so that a controller can accurately recognize a heating state of an actual food, and a detection voltage of a sensor using a reference load Implement the calibration method.

1 is a configuration diagram of a device in which a sensor is connected to a control unit of a microwave oven according to the present invention.

2 is a flowchart of a detection voltage calibration method of a sensor using a reference load according to the present invention.

* Description of the symbols for the main functions of the drawings *

7 sensor part 8 smooth part

9 control unit 10 antenna

11: first diode 12: first resistor

13: 2nd diode 14: 3rd diode

15: first capacitor 16: second resistor

In order to achieve the above object, the present invention provides a microwave oven in which a controller recognizes a heating state of food based on a detected voltage value detected by a microwave detection sensor, wherein the sensor detects a detected voltage value with respect to a reference load. A detection coefficient value detection step for comparing the detection voltage value detected in the detection step with a preset reference voltage value, calculating a correction coefficient according to the comparison result, and storing the calculated correction coefficient And calibrating the detected voltage value by the stored calibration coefficients.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment according to the present invention will be described in detail.

1 is a block diagram of an apparatus in which a sensor is connected to a control unit of a microwave oven according to the present invention. As shown in FIG. 1, as in the related art, a device in which a sensor is connected to a control unit of a microwave oven is a state value reflecting a heating state of a food, receives a microwave reflected from a cooking chamber, extracts a signal wave, and is proportional to the signal wave. A sensor unit 7 for converting to a voltage, a smoothing unit 8 connected to an output terminal of the sensor unit 7 so as to smooth the output signal of the sensor unit 7 with a DC signal, and the smoothed output signal. It consists of a control unit 9 connected to the smoothing unit 8 so as to recognize the heating state of the food based on this.

The sensor unit 7 includes an antenna 10 for receiving a signal of microwaves reflected in the cooking chamber, a first diode 11 connected to the antenna 10, and a first diode connected in series with the first diode 11. The first resistor 12 includes a second diode 13 connected between the first resistor 12 and the ground, and a third diode 14 connected in series with the second diode 13.

The smoothing part 8 also comprises a first capacitor 15 connected between the output terminal of the sensor part 8 and the ground, and a second resistor 16 connected in parallel to the first capacitor 15.

Referring to the operation of FIG. 1, when a user puts food into a cooking chamber and operates a microwave to cook, the magnetron oscillates to generate a microwave of 2450 MHz, and the food is cooked by the generated microwave. The sensor unit 8 receives the microwaves reflected in the cooking chamber through the antenna 10.

The microwaves received through the antenna 10 are rectified by the first diode 11 and the first resistor 12. The high voltage microwave is bypassed to the ground side by the second diode 13.

The signal rectified by the first diode 11 and the first resistor 12 is smoothed into a DC signal by the first capacitor 15 and the second resistor 16 so that the controller 9 at the rear end may recognize the signal. Regulated output voltage. The control unit 9 recognizes the heating state of the food in the cooking chamber based on the output voltage.

2 is a flowchart of a detection voltage calibration method of a sensor using a reference load according to the present invention. As shown in FIG. 2, when a food having a reference load is put in a microwave and operated, a magnetron oscillates to generate microwaves in the cooking chamber, and the sensor receives microwaves and converts them into voltage values (S100). Send to the controller.

In the step S100, the sensor is about 0.5 for a time when the tray is rotated one time (for example, about 12 seconds) to obtain a more stable value after the predetermined time (about 4 seconds) including the ripple in the microwave of the magnetron. Detects the voltage of the microwave reflected in the cooking chamber at the second interval and transmits the detected voltage to the control unit, and the control unit recognizes a more accurate voltage value as a detection voltage value of the food by averaging the transmitted voltage values.

When the detection voltage value is detected in the step S100, the control unit initializes the K to obtain a correction coefficient such that the detection voltage value is a preset reference voltage value using a reference load in a microwave of a preset reference model. After initializing the value to 0 (S101) and increasing the initial value (K = 0) by a preset increase amount (for example, 0.01) (S102), if the preset reference voltage value is A00 _16, for example, the reference voltage value Compare the size of (A00 ₁₆ ) and S * K (0.01 ₁₀ ) (S103).

The comparison reference voltage value (A00 _16)> S * K (0.01 ₁₀₎ If by the return to step (S102) increased by the increase amount _{(0.01. 10)} to the K task the step of performing the step (S103) ( Until the condition of S103) is satisfied.

The steps S102 and 103 are repeated to increase the preset increment amount 0.01 by the number of times the value of K is repeated. If the reference voltage value (A00 ₁₆ ) ≤ S * K in the comparison step (S103), the controller controls the effective range of the preset K corresponding to the effective range of the preset S, where the value of K experimentally accurately reflects the heating state of the food. (E.g., the detection value of S is too high due to a magnetron or a sensor error, but a low value is detected on the contrary, and the control unit prevents an incorrect determination of the heating state of the food based on the detected value. The effective range of the K value corresponding to the effective range of S is set in advance, and in the case of the above example, 25 ₁₆ to FE ₁₆ .

If the K value is not included in the valid range in the determination step S104, the controller determines that it is an error (105).

If the K value is within the valid range in the determining step S104, the controller may further include a first reference value (for example, B0 ₁₆ ) that is preset according to the output level of the S within the valid range to obtain a more accurate value. Comparison (S106)

According to an experiment, the first reference value converges to a constant value which does not need to consider an error when the K value is lower than the reference value based on a reference value according to a correlation between the value of S and K. If the value is larger than this value, a linearly increasing value exists, wherein the reference value is the first reference value.

If the result of the comparison, K <first reference value (B0 ₁₆ ), the control unit determines the K value by using a second preset reference value 8A ₁₆ that converges to one value by an experiment (S107), and sets the K value to Y pyrom ( EEPROM) (S109).

If the comparison result K ≥ the first reference value (B0 ₁₆ ), the control unit determines the K value with the third reference value calculated by the equation K = K + (K-25 ₁₆ ) which is linearly increased by the experiment. (S108), the K value is stored in EEPROM (S109).

That is, the value of any one of the third reference values calculated by the equation of the second reference value 8A ₁₆ and K = K + (K-25 ₁₆ ) is obtained in the EEPROM. Is stored.

Thereafter, the controller corrects the detected voltage value by multiplying the stored correction coefficient by the detected voltage value detected by the sensor in actual use when the real food is put into the microwave (S110) and based on the corrected value. To recognize the heating state of the food.

As described in detail above, the present invention stores each calibration coefficient required to calibrate the detected voltage of each sensor of the microwave oven to a preset reference voltage using a reference load, and stores the calibration coefficients in the EEPROM and stores the stored calibration. By correcting the detection voltage of the sensor when the actual food is input and operated for each product of the microwave oven using the coefficient, it is possible to accurately reflect the heating state of the actual food, thereby reducing the error rate of the microwave.

Claims (5)

In the microwave oven, the control unit recognizes the heating state of the food based on the detected voltage value detected by the microwave detection sensor, A detection voltage value detection step of detecting a detection voltage value by the sensor with respect to a reference load; A calibration coefficient calculating step of comparing the detected voltage value detected in the detecting step with a preset reference voltage value and calculating a calibration coefficient according to the comparison result; Storing the calculated calibration coefficients; And a calibration step of calibrating a detected voltage value in actual use by the stored calibration coefficients. The method of claim 1, The detecting voltage value detecting step includes detecting the output of the sensor a plurality of times for a preset time period and averaging the detected detection voltage value. . The method of claim 1, The calculating of the correction coefficient may include initializing an initial correction coefficient to calculate the correction coefficient and increasing the preset correction coefficient by a preset increase amount. Comparing the reference value with an operation value multiplied by the increased calibration coefficient and the detected voltage value; Increasing the calibration coefficient by the increase amount when the reference voltage value is greater than the calculated value as a result of the comparison; And calculating the calibration coefficient when the reference voltage value is smaller than the calculation value as a result of the comparison. The method of claim 3, wherein Determining whether the calibration coefficient is within a preset valid range if the reference voltage value is less than the calculated value as a result of the comparison; Calculating the correction coefficient if the correction coefficient is within the valid range as a result of the determination; And determining that the error is an error if the correction coefficient is not within the effective range. The method of claim 4, wherein Comparing the calibration coefficient with a first reference value preset according to an output level of the detection voltage value within the valid range if the calibration coefficient is within the valid range as a result of the determination; Determining the calibration coefficient as a second reference value which is preset and smaller than the first reference value if the calibration coefficient is smaller than the first reference value; And if the calibration coefficient is greater than the first reference value, determining the calibration coefficient as a third reference value which is set in advance and larger than the first reference value. .