KR19990060451A - Temperature control method of heating device - Google Patents

Abstract

The present invention relates to a temperature control method of a heating apparatus capable of reducing fluctuations in temperature change.

According to the present invention, there is provided a heating apparatus including: a first step of heating to a first temperature having a predetermined temperature difference from a set temperature; A second step of heating at a relatively low temperature rise rate at the first temperature; And a third step of heating to maintain the set temperature by intermittent heating when the actual temperature reaches the set temperature during heating to an output value determined based on the temperature increase rate according to the characteristics of the heating chamber. Doing. The output value of the 3rd step is determined based on the duty value determined by the product of the constant K1 about the temperature increase rate of a heating chamber, and the difference value of a preset temperature and an actual temperature. And the output value of the third step, the intermittent heating time may be determined to include the temperature deviation of the actual temperature with respect to the set temperature.

Description

Temperature control method of heating device

The present invention relates to a temperature control method of a heating apparatus, and more particularly, to a temperature control method capable of temperature control in a state closest to a more precisely set temperature in consideration of the inherent characteristics of the heating apparatus.

In a cooking apparatus such as a microwave electric rice cooker, the conventional temperature control method, when the present temperature is lower than the target temperature, the heating unit performs a heating operation by applying a heating source such as a heater, and in the sensing unit that the target temperature has been reached. When it sensed, it was based on the method which cuts off the electricity supply of a heater.

A conventional temperature control method for a microwave oven with a heater as an example of the temperature control method will be described below with reference to the accompanying drawings.

A microwave oven with a built-in heater is a microwave oven that has a direct heating method for heating food to be cooked by heat generation of this heater, in addition to a dielectric heating method, which is a heating method unique to the microwave oven. .

The microwave includes a cooking chamber (Cavity) for storing the food to be cooked, an electric heater for heating the inside of the cooking chamber, a magnetron unit for generating electromagnetic waves to dielectrically heat the food to be cooked, and a temperature sensing unit for sensing the temperature of the cooking chamber. It is configured by.

1 is an operation flowchart of a temperature control method of the prior art.

When the heater dish is selected in the start step, the following temperature control steps are performed.

When the heater cooking is selected (S10), first, it is determined whether the temperature value in the cooking chamber input through the temperature sensing unit is lower or higher than the set temperature (target temperature) value (S12). This step S12 is a step for determining whether or not the heater needs to be heated.

If the temperature detection value in the cooking chamber is smaller than the set temperature or the target temperature value (YES), the heater on step S14 is performed. This step is to raise the temperature in the cooking chamber by heating the heater.

On the other hand, if the temperature in the cooking chamber is not lower than the set temperature, since the heater does not need to be heated, the heating signal of the heater is not output, and the second determination step S16 is performed. The second determination step S16 is a step of determining whether to cut off the power of the heater (S18) or maintain the current state (S20).

If the determination result in the second judging step S16 indicates that the actual temperature is higher than the set temperature, that is, if the temperature sensing value in the cooking chamber is higher than the set temperature or the target temperature value, the power cutoff step S18 of the heater is performed. On the contrary, if the temperature detection value in the chamber is lower than the set temperature value or the target temperature value in the second determination step, the current state is maintained (S20).

On the other hand, in the current state maintenance step, the temperature change occurs toward the point where the temperature in the cooking chamber and the external temperature are balanced. This change in temperature is determined by the change time of the cooking chamber and external insulation. In the above-described temperature control method of the related art, it can be seen that the power of the heater is cut off when the temperature sensing value in the cooking chamber simply reaches a predetermined value.

Actually, there is a slight temperature rise immediately after the heater is turned off. After that, as described above, the temperature in the cooking chamber decreases depending on the external temperature or the condition according to the heat insulating condition in the cooking chamber.

On the other hand, when the temperature detection value in the cooking chamber falls to a certain value, the heating operation of the heater is performed again. However, the temperature in the cooking chamber does not reach the desired temperature value within a short time depending on the heat capacity of the heater and the heating capacity of the cooking chamber. Do not. Therefore, the temperature in the cooking chamber drops for a predetermined time even after the heater power is applied.

According to the fluctuation of the temperature as described above, in the conventional cooking apparatus, the temperature is controlled within a range of a constant upper and lower width, not controlled as the exact temperature as desired, and there is a problem such as deterioration of the cooking state. have.

Such a problem may be pointed out as a more significant problem especially when cooking is required for a certain time while maintaining a constant set temperature, or in a cooking apparatus that requires a constant temperature to be maintained at a constant temperature.

In addition, since the temperature control method of the conventional method is not a method of controlling in consideration of the heat capacity of the cooking chamber, an unbalanced cooking quality may be a factor depending on the size of the cooking apparatus, in particular, the heat capacity of the cooking chamber.

In order to solve the above problems, an object of the present invention is to provide a temperature control method which can be controlled with a minimum temperature deviation.

Another object of the present invention is to provide a temperature control method for controlling a cooking apparatus in consideration of heat capacity characteristics of a cooking chamber.

1 is a flow chart for explaining a temperature control method according to the prior art.

2 is a flow chart for explaining the temperature control method according to the present invention.

The temperature control method of the present invention includes a first step of heating to a first temperature having a predetermined temperature difference with a set temperature; A second step of heating at a relatively low temperature rise rate at the first temperature; And a third step of heating to maintain the set temperature by intermittent heating when the actual temperature reaches the set temperature during heating to an output value determined based on a temperature increase rate according to the characteristics of the heating chamber.

The output value of the third step may be determined based on a duty value determined by a product of a constant K1 of the temperature increase rate of the heating chamber and a difference value between the set temperature and the actual temperature, or the actual temperature of the set temperature. It is possible to determine including the temperature deviation.

According to another embodiment of the present invention, a heating step of heating to a predetermined temperature deviation range with respect to the set temperature; A determination step of determining whether there is a time when the set temperature and the actual temperature match each other; If the set temperature and the actual temperature do not coincide with each other, it is heated until it reaches the set temperature. If there is a time when the actual temperature coincides with the set temperature during heating, the output is determined based on the temperature increase rate according to the characteristics of the heating chamber. It discloses a temperature control method of a heating apparatus comprising a control step of heating to maintain a set temperature by.

According to the present invention as described above, by controlling the intermittent heating time in consideration of the intrinsic characteristics of the chamber at the set temperature, the effect that can provide a control method that can heat or warm the object most efficiently with respect to the set temperature You can expect

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

FIG. 2 is a flow chart showing an embodiment in which the temperature control method according to the present invention is applied to a microwave oven having a cooking chamber and a heater having a certain characteristic.

The temperature control method according to the present invention can be used in any heating apparatus having a heating source, and of course, it can be easily applied to a heating apparatus such as a microwave oven or a warm rice cooker. 2 shows an embodiment applied to a microwave oven using a heater as one heating source, and the present invention will be described through these embodiments.

The user may select a grill function of the microwave oven to heat food using a heater. Grill cooking selection step (step 30) in Figure 2 means this. When the grill dish is selected in the thirtieth step, power is applied to the heater to enable the object.

While the heating by the heater is in progress, the actual temperature of the current cooking chamber is measured, and the temperature difference between the temperature detection value and the set temperature is calculated (step 32). At this time, if the temperature difference is greater than or equal to the predetermined value K, for example, 10 ° C or more, it means that the difference between the target temperature and the present temperature is remarkable, and therefore it is necessary to continue heating the heater (step 33). However, when the temperature difference is smaller than the predetermined value K, it means that the destination and the current temperature are within a close difference, and thus, the heater is heated in an intermittent heating step (S35) which repeats the energization and the disconnection without continuously heating the heater. Or the duty value control step (S36) for controlling the on or off time according to the duty value.

The control by the intermittent heating or the duty value as described above is to prevent the cooking chamber from being heated above the target temperature by slowing down the temperature increase rate in the cooking chamber.

For this purpose, the predetermined value may have a value other than 10 ° C. In addition, this value should be determined in consideration of the thermal insulation characteristics of the cooking chamber, the temperature sensing characteristic of the temperature sensor in the cooking chamber, and the heat capacity of the heater.

On the other hand, the intermittent heating step (step 35) and the duty value control step (step 36) are selected by a step of checking whether the set temperature is consistent with the temperature detection value. That is, the intermittent heating step (step 35) is performed when the temperature detection value does not reach the set temperature, but once the set temperature is reached, the duty value control step (step 36) is performed. In other words, the intermittent heating step (step 35) is performed until the temperature detection value first reaches the set temperature value, but the duty value control step (step 36) after the temperature detection value reaches the set temperature value once Is performed.

In the intermittent heating step S35, the heater is energized for a predetermined time (for example, 3 seconds), and the cycle of powering off for a predetermined time (for example, 7 seconds) is repeated. This is for gently raising the temperature of the cooking chamber.

The intermittent heating is to prevent the cooking chamber from being heated for longer than the purpose by slowing down the rate of temperature increase in the cooking chamber. The time period of the intermittent heating step (step 35) is a thermal insulation characteristic of the cooking chamber and the temperature in the cooking chamber. It is desirable to determine the temperature sensing characteristics of the detector and the heat capacity of the heater.

On the other hand, in the duty value control step (step 36), the control time of energization or disconnection of the heater is determined by the following formula.

Duty value = K1 x {set temperature-(actual temperature + K)}... Formula (1)

Heater control time = 100 x (1-duty value)... Formula (2)

In said Formula (1), K1 is a variable in consideration of the characteristic of a cooking chamber (namely, the space heated). As a property of the cooking chamber for determining such a variable, it is a constant determined by the cooking chamber's unique characteristics such as the size and heat insulation characteristics of the cooking chamber and the capacity of the heater, and is determined in consideration of the temperature rise up to the present. In this case, K1 should be set such that the duty value has a value between 0 and 1. And K which represents a predetermined compensation value in Formula (1) is a value which means the temperature width with respect to what kind of temperature range it operates with when it reaches a preset temperature. In the duty control, by controlling the intrinsic characteristics considering the relationship between the inside of the heating chamber and the heating source and the compensation value, more stable and accurate temperature control is possible with respect to the set temperature.

In the formula (2), the heater control time means the on time or the off time of the heater in the duty value control step. When the duty value is obtained by equation (1), the on time or off time of the heater can be determined by equation (2) based on this duty value. That is, the on or off of the heater is controlled during the time ratio obtained by equation (2). For example, when the basic period for time control is N, if 50% is obtained according to Equation (2), the time of N X 50% can be determined as on time or off time.

Thus, for example, when the control time of the heater is based on a period of 10 seconds, the on / off is repeated at a time interval equal to the rate obtained from the heater control time based on the duty value. For example, if 10% is obtained from the heater control time, the heater operation is repeated for 9 seconds after the cycle is maintained after being kept on for 1 second, or for 1 second after being kept on for 9 seconds. The cycle to keep off can be repeated.

When the present invention is specifically applied to each cooking chamber, it is basically used to increase or decrease the time to turn on the heater according to the characteristics of the individual cooking chamber.

According to the heater control time value determined as described above, the energization (step 39) or the power cut-off (step 40) of the heater is determined. That is, the on time of the heater may be determined or the off time may be determined using the above-described duty value.

On the other hand, as another embodiment of the present invention, as described above, by measuring the actual temperature of the current cooking chamber, and checking the rate of increase of the temperature in the cooking chamber other than the method of calculating the temperature difference between the temperature detection value and the set temperature (step 32). Thus, time control can be started. That is, the continuous heating step (step 33) of the heater is performed until the temperature rise width per unit time of the cooking chamber reaches a predetermined value, and after the temperature rise width reaches the predetermined value, the set temperature and the temperature sensing value are the same. It is also possible to configure such that the step (step 34) of checking whether there is a temperature has been performed.

Although the control method according to the present invention configured as described above has been described by way of example in which heating by a heater is performed in a microwave oven having a heater, it is used for any heating apparatus having a predetermined heating chamber and a heating source. Of course it can be.

In addition, the control method according to the present invention may be used, for example, when heating for a predetermined time while maintaining the set temperature, or may be used even when thermal insulation is performed at the set temperature.

As described above, since the constants such as K and K1 can be changed and set to suit the characteristics of each cooking chamber, the controller merely adjusts the parameters of the algorithm to reflect the characteristics of each cooking chamber for all devices requiring temperature control. By doing so, it becomes possible to control the temperature in which fluctuation of the temperature change is reduced.

Particularly, the present invention provides an effect capable of controlling the temperature by reducing the deviation of the warming or temperature control in a cooking apparatus requiring temperature control or warming control such as a microwave oven and a rice cooker.

In addition, it will be apparent to those skilled in the art that the temperature control method of the present invention as described above can be widely applied to other devices that require particularly precise temperature control or control of thermal insulation.

Claims (10)

A first step of heating to a first temperature having a predetermined temperature difference and a predetermined temperature; A second step of heating at a relatively low temperature rise rate at the first temperature; And When the actual temperature reaches the set temperature during heating, the temperature control of the heating apparatus comprising a third step of heating to maintain the set temperature by intermittent heating to the output value determined based on the temperature rise rate according to the characteristics of the heating chamber Way. The method of claim 1, wherein the output value of the third step, A temperature control method of a heating apparatus, determined based on a duty value determined by a product of a constant K1 of a heating rate of a heating chamber and a difference value between a set temperature and an actual temperature. According to claim 1 or 2, wherein the output value of the third step, The intermittent heating time is a temperature control method of the heating apparatus that is determined including the temperature deviation of the actual temperature with respect to the set temperature. The method of claim 3, wherein the output value of the third step, Of the heating apparatus determined by K1 × {set temperature- (actual temperature + K)} value with respect to the constant K1 considering the temperature increase rate of the heating chamber and the deviation K between the actual temperature and the set temperature. Temperature control method. 5. The temperature control method of a heating apparatus according to claim 4, wherein the intermittent heating time is determined on or off by a time ratio based on the output value. A heating step of heating to a predetermined temperature deviation range with respect to the set temperature; A determination step of determining whether there is a time when the set temperature and the actual temperature match each other; And If there is no match between the set temperature and actual temperature, it is heated until reaching the set temperature. If there is a time when the actual temperature matches the set temperature during heating, the output value is determined based on the temperature rise rate according to the characteristics of the heating chamber. And a control step of heating to maintain the set temperature. The method of claim 5, wherein the heating step, A first heating step of heating to a predetermined temperature range with respect to the set temperature; And a second heating step of heating the resin to have a relatively lower temperature rise than that of the first heating step. The method of claim 6, wherein the intermittent heating output value of the control step, A temperature control method for a heating apparatus, determined based on a constant (K1) in consideration of a temperature rising rate of a heating chamber and a duty value determined by a product of a difference value between a set temperature and an actual temperature. According to claim 8, The intermittent heating output value of the control step, The intermittent heating time is a temperature control method of the heating apparatus that is determined further comprising a temperature deviation of the actual temperature to the set temperature. 10. The temperature control method of claim 9, wherein the control time during intermittent heating of the control step is determined on or off by a time ratio based on the output value.