KR102369153B1 - Electric cooker - Google Patents

Abstract

The present invention relates to an electric cooker that minimizes a temperature difference between a lid portion of an inner pot by using the heating characteristic of a driving coil provided in a steam discharge unit when performing a warming process.
The electric cooker according to the present invention includes an input unit for obtaining a user input, a temperature sensing unit for sensing an internal or external temperature of the inner pot, a heating unit for applying heat to the inner pot, and an opening and closing operation of the valve by receiving power. A steam discharge unit provided with a driving coil to and a control unit configured to control the opening or closing operation of the steam discharging unit to be performed, and to perform a heating operation of the steam discharging unit during the closing operation of the steam discharging unit.

Description

Electric cooker {ELECTRIC COOKER}

The present invention relates to an electric cooker, and more particularly, to an electric cooker that minimizes a temperature difference in a lid portion of an inner pot by using the heat-generating characteristic of a driving coil provided in a steam discharge unit when performing a warming process.

An electric cooker is a device that cooks food by heating the inner pot in a state in which food materials to be cooked are contained in the inner pot to create a high-temperature and high-pressure state. Such an electric cooker is often referred to as an electric rice cooker, but in recent years, it has been used for multiple purposes to suit the name of the electric cooker so as to cook various types of food other than rice.

The basic structure of a general electric cooker consists of a main body, an inner pot accommodated in the main body, and a main body lid covering the upper part of the main body. The main body is provided with a heating means to heat the inner pot, and the main body lid is provided to open and close the upper part of the main body.

1 is an exploded perspective view of a main body lid of a conventional electric cooker, and FIG. 2 is an exploded perspective view showing a state in which the inner pot lid is separated from the main body lid of the conventional electric cooker.

1 and 2, the main body lid of the conventional electric cooker is detachably detachable to cover the upper part of the inner pot at the lower end of the lid 40 and the lower end of the lid 40 for opening and closing the upper part of the main body (not shown). It is made to include a provided inner pot lid (50), a top plate (60).

The top plate 60 is coupled to the steam control unit 70 is seated in the receiving groove 62 for controlling the steam in the inner pot. The steam control unit 70 includes an automatic steam discharge unit 90 that discharges steam from the inner pot when the internal pressure of the inner pot becomes greater than or equal to a predetermined pressure, and from the inner pot during or after the cooking process is completed under the control of the controller. A communication hole through which the steam discharge unit 80 (solenoid valve device) for discharging steam, the automatic steam discharge unit 90, and the steam discharge unit 80 communicate is formed, and the automatic steam discharge unit 90 and the steam discharge unit A fixing plate 72 on which the 80 is mounted is provided.

The top plate 60 is coupled to the lower surface of the lid 40 by attaching a heater 65 to the upper side excluding the receiving groove 62 , and the inner pot lid 50 is the top plate 60 by the fixing part 55 . ) is detachably coupled to the lower part.

Here, the automatic steam discharge unit 90 and the steam discharge unit 80 are mounted on the fixing plate 72 , and since the fixing plate 72 is coupled to the receiving groove 62 , the heater 65 cannot be attached thereto, so the steam control unit 70 and the receiving groove 62 and the communication groove 52 of the inner pot lid 50 corresponding to the bottom surface of the receiving groove 62 do not have direct contact with the heater 65 . Due to this structural problem, when the electric cooker is kept warm, water enters the bottom part of the inner pot lid 50 corresponding to the area where the heater is not provided, and the back part 52a and the fixing part 55 of the communication groove 52. Condensation occurs, and the condensed water falls on the rice inside the inner pot, turning the rice white.

This whitening phenomenon is caused not only in the inner pot lid detachable electric cooker as shown in FIGS. 1 and 2 but also in the electric cooker in which the inner pot lid is not detached. In addition, in order to solve the whitening phenomenon, a separate heating device may be installed in a portion where a heater is not provided. Loss and damage occur.

In addition, when the steam discharge unit 80 is closed for a long time in the warming process in the conventional electric cooker, the pressure rises inside, causing a problem that the lid of the main body is not opened.

The present invention is to provide an electric cooker that minimizes the temperature difference of the inner pot lid portion by using the heating characteristics of the driving coil provided in the steam discharge unit during the warming process and adjusts the heating temperature of the driving coil using the PWM control method. The purpose.

In addition, the present invention provides an electric cooker that maintains the internal pressure of the inner pot at an appropriate level by maintaining the steam outlet in a closed state after the internal temperature is stabilized based on the internal temperature of the inner pot during the warming process. The purpose.

The electric cooker according to the present invention includes an input unit for obtaining a user input, a temperature sensing unit for sensing an internal or external temperature of the inner pot, a heating unit for applying heat to the inner pot, and an opening and closing operation of the valve by receiving power. A steam discharge unit provided with a driving coil to and a control unit configured to control the opening or closing operation of the steam discharging unit to be performed, and to perform a heating operation of the steam discharging unit during the closing operation of the steam discharging unit.

In addition, the control unit applies a first control signal for performing voltage cutoff for the opening operation of the steam discharge unit and a second control signal for performing voltage supply or voltage cutoff for the closing operation of the steam discharge unit to the valve driving unit. It is preferable to do

In addition, the second control signal is an on control signal for supplying the voltage to the steam discharge unit so that the closing operation and the heating operation of the steam discharge unit are performed, and an off control signal for cutting off the voltage to the steam discharge unit. It is desirable to include a configured pulse width modulation (PWM) control signal.

Preferably, the second control signal includes an ON control signal for supplying a voltage to the vapor discharge unit for a reference time before the pulse width modulation (PWM) control signal.

In addition, it is preferable that the application time of the on control signal is set to a limit time or more so that the closing operation of the vapor discharge unit is maintained.

In addition, it is preferable that the control unit calculates the elapsed time of the warming process, and if the calculated elapsed time of keeping warm is equal to or greater than the reference control time, it is preferable to continuously maintain the opening operation of the steam discharging unit.

In addition, the control unit determines the stabilization of the internal temperature on the basis of the internal temperature sensed by the temperature sensing unit in the open state of the vapor discharge unit, and when the internal temperature is stabilized, the closing operation of the steam discharge unit is It is desirable to do so.

The present invention improves the thermal insulation quality by preventing whitening by minimizing the temperature difference of the inner pot lid part by using the heating characteristics of the driving coil provided in the steam discharge part during the warming process, and heats the driving coil using the PWM control method. By controlling the temperature, there is an effect of solving the problem of sticking between the parts in the steam outlet.

In addition, the present invention can reduce the temperature difference of the inner pot lid portion to reduce the amount of heating by the heating unit while maintaining the food within the desired keeping temperature range, there is an effect of reducing power consumption.

In addition, the present invention maintains the internal pressure of the inner pot at an appropriate level by maintaining the steam outlet in a closed state after the internal temperature is stabilized based on the internal temperature of the inner pot during the warming process, and the lid is closed for eating. There is an effect that can solve the problem that the lid does not open due to internal pressure when opening.

In addition, the present invention maintains the steam discharge unit in a closed state during the warming process, but opens the steam discharge unit at regular time intervals, and continuously opens the steam discharge unit when the warming operation is performed for more than a reference control time to remove the components in the steam discharge unit It is effective in solving the problem of adhesion between the liver.

1 is an exploded perspective view of a main body lid of a conventional electric cooker.
2 is an exploded perspective view illustrating a state in which the inner pot lid is separated from the main body lid of the conventional electric cooker.
3 is a block diagram of an electric cooker according to the present invention.
4 is a control flowchart of the electric cooker of FIG. 3 .
5 is an example of the voltage across the vapor discharge unit according to the first and second control signals.
6 is a view illustrating a position of a temperature measuring portion inside the electric cooker.
7 is a view showing the position of the temperature measurement portion of the steam outlet.

Hereinafter, the present invention will be described in detail through examples and drawings.

3 is a block diagram of an electric cooker according to the present invention. The electric cooker includes a power supply unit 110 that receives commercial power and supplies necessary power, a display unit 120 that displays a menu or a cooking process currently in progress, and a heating unit that applies heat to the upper, side, and lower sides of the inner pot ( 130), and the input unit 140 that receives a menu selection, a cooking process, selection of a duty ratio of a PWM signal, etc. from a user, and continuously detects the internal temperature of the inner pot and/or the external temperature (environmental temperature) of the electric cooker The temperature sensing unit 150 , the valve driving unit 160 receiving a control signal from the control unit 200 and applying a voltage to the steam discharging unit 180 , and steam discharging operated by the voltage from the valve driving unit 160 . The unit 180 and a control unit that performs a standby process, a cooking process, a warming process, etc. by controlling the above-described components, and controls the application of a voltage to the steam discharge unit 180 to perform an opening and closing operation of the valve ( 200) consists of

In this embodiment, the power supply unit 110, the display unit 120, the input unit 140, and the temperature sensing unit 150 correspond to the level of technology recognized by those of ordinary skill in the art to which the present invention belongs. , the description thereof is omitted. The invention also includes the devices shown in FIGS. 1 and 2 .

The heating unit 130 includes an upper heating unit (same as the heater 65 of FIG. 1) mounted on the lid to heat the upper side of the inner pot, a side heating unit for heating the side of the inner pot, and heating the lower side of the inner pot It consists of a lower heating part.

The valve driving unit 160 receives a control signal from the control unit 200 and controls the voltage to the vapor discharge unit 180 in response to the control signal. The steam discharging unit 180 includes a driving coil for discharging and blocking steam (opening and closing of the valve) by driving the plunger by receiving voltage. The control unit 200 controls the above-described components to perform the standby process, perform the cooking process according to menu selection and a cooking start command, and perform the warming process after the cooking process, or a newly input keep warm Perform the warming process according to the command. The control unit 200 controls the valve driving unit 160 to open and close the steam discharge unit 180 according to the performed process while performing the standby process, the cooking process, the warming process, and the like.

In the present embodiment, the control signal includes a first control signal for an opening operation of the vapor discharge unit 180 and a second control signal for a closing operation of the vapor discharge unit 180 . The valve driving unit 160 does not supply separate power to the steam discharge unit 180 in response to the first control signal, so only an opening operation is performed and no heating operation is performed, and in response to the second control signal, the steam discharge unit ( 180) to supply power to the closing operation, and the driving coil in the steam discharge unit 180 performs a heating operation. The control unit 200 uses the heating characteristic generated by the driving coil during the closing operation of the steam discharging unit 180 by using a second control signal including a PWM (Pulse Width Modulation) control signal in the warming process, and the detailed The content is described below.

In addition, the controller 200 determines whether the internal temperature of the inner pot is stabilized using the inner temperature of the inner pot detected by the temperature sensor 150 in the open state of the steam discharge unit 180 while performing the warming process, and , After the internal temperature of the inner pot is stabilized, the steam discharge unit 180 is maintained in a closed state to control the internal pressure of the inner pot to be maintained at an appropriate level. Matters related to this internal pressure control will be described in detail below.

4 is a control flowchart of the electric cooker of FIG. 3 , and FIG. 5 is an example of voltages at both ends of the steam discharge unit according to the first and second control signals. The control unit 200 controls the heating unit 130, the valve driving unit 160, and the steam discharging unit 180 using the internal temperature of the inner pot detected by the temperature sensing unit 150 according to the cooking algorithm to control the cooking process. carry out After completion of the cooking process, the control unit 200 automatically performs the keep-warm process or when the keep-warm process is performed according to a keep-warm execution command from the input unit 140, step S11 is performed. In addition, the control unit 200 calculates the elapsed time from the execution of step (S11) to the end of the warming process.

In step S11, the control unit 200 generates a first control signal and applies it to the valve driving unit 160, and the valve driving unit 160 performs an opening operation of the steam discharge unit 180 in response to the first control signal. make it performed In addition, since the steam discharging unit 180 does not perform a heating operation during the opening operation, the temperature of the fixing plate 72 on which the steam discharging unit 180 is mounted is lowered and water is condensed, so that the control unit 200 controls the fixing plate ( 72), the heating target temperature or the heating output of the heating unit 130 (or the heating unit on the upper side of the heating unit 130) is adjusted upward.

In step S13, the control unit 200 compares the calculated elapsed warming time with the pre-stored reference control time. If the calculated elapsed warming time is greater than or equal to the reference control time, the process proceeds to step S11 to maintain the opening operation, otherwise it proceeds to step S15.

This reference control time corresponds to a time for preventing the problem of sticking in the vapor discharge unit 180, and is set to, for example, 20 hours. In step S23 of the control flowchart, the steam discharge unit 180 performs a closing operation, and a current flows in the driving coil to generate heat. When the closing operation and the heating operation are maintained for a long time, the Parts contacted within the steam discharge unit 180 by performing the closing operation in a high temperature state (eg, a valve body having a steam inlet communicating with the inside of the electric cooker, a diaphragm for opening and closing the steam inlet, etc.) ) is adhered to each other, thereby delaying or not opening the opening operation of the steam discharge unit 180 occurs. In order to solve the problem of sticking due to the heat operation during the closing operation, the control unit 200 proceeds to step S11 when the elapsed warming time is greater than or equal to the reference control time, and the steam discharge unit 180 maintains the open operation. to stop the heating operation to prevent sticking between the components in the steam discharge unit 180 .

In step S15 , the control unit 200 determines whether the internal temperature of the inner pot detected by the temperature sensing unit 150 is equal to the warming target temperature. If the inner temperature of the inner pot is the same as the target keeping temperature, the process proceeds to step S17, otherwise proceeds to step S11.

In step (S17), the control unit 200 starts the calculation of the elapsed determination time or initializes the elapsed time for determination in order to determine the stabilization of the internal temperature of the inner pot, and then starts the calculation and proceeds to step (S19).

In step S19, the control unit 200 determines whether the internal temperature of the inner pot is within a reference range while increasing the elapsed time determined. If the inner temperature of the inner pot is within the reference range, proceed to step (S21), otherwise proceed to step (S11). The reference range is, for example, a temperature range from the lower limit temperature (heat retention target temperature -4°C) to the upper limit temperature (heat retention target temperature + 4°C), and the reference range is variable. In addition, when the warming target temperature is changed, the lower limit temperature and the upper limit temperature of the reference range may also be changed.

In step S21, the control unit 200 determines whether the determined elapsed time is greater than or equal to the reference elapsed time. If the judgment elapsed time is greater than or equal to the reference elapsed time, the process proceeds to step S23; otherwise, the process proceeds to step S19. The reference elapsed time corresponds to a time for determining whether the internal temperature of the inner pot is stabilized, and is set to, for example, 10 minutes.

In step S23, the control unit 200 generates a second control signal including the PWM signal and applies it to the valve driving unit 160, and the valve driving unit 160 responds to the second control signal to the steam discharge unit 180 ) to perform the closing operation and heating operation. The controller 200 may use the second control signal to adjust the heating temperature (or the amount of heat) in the closing operation of the steam discharging unit 180 and the heating operation. This point will be described in detail in conjunction with the description of FIG. 5 below. In addition, since the control unit 200 performs a heating operation during the closing operation of the steam discharging unit 180, the heating unit 130 (or the upper heating unit of the heating unit 130) of the heating target temperature or heating output down-regulate

In step S25 , the control unit 200 determines whether an open operating condition of the steam discharge unit 180 occurs. If the open operating condition occurs, the process proceeds to step S11; otherwise, the process proceeds to step S27. Here, the open operation condition is when the internal temperature of the inner pot is out of the reference range, when the lid is opened, when there is a user input through the input unit 140, when the power is re-supplied after being cut off, and the elapsed warming time is the reference control time Including a case equal to less than one or more lower control times, the open operating condition will be described in detail below.

In step S27 , the control unit 200 determines whether the user has inputted the end of the warming process through the input unit 140 . If the end of the warming process is input, the control of the steam discharge unit 180 is terminated, otherwise the process proceeds to step S23.

Through the above-described steps (S15) to (S21), the controller 200 determines that the elapsed time determined while the internal temperature of the inner pot is continuously maintained within the reference range while performing the warming process is greater than or equal to the reference elapsed time By checking, it is checked whether the internal temperature of the inner pot is stabilized, and if it is not in a stable state, the opening operation of the steam discharge unit 180 is performed in step (S11), and the steam is discharged in step (S23) only when it is in a stable state. A closing operation and a heating operation of the unit 180 are performed. The stabilization confirmation process is required before the closing of the steam discharging unit 180 is that, when the steam discharging unit 180 is immediately closed upon completion of cooking (cooking), the internal pressure of the inner pot increases, so that the main body lid does not open, This is because the increased internal pressure of the inner pot is continuously maintained even when the inner temperature of the inner pot is lowered, so that the main body lid is not opened. Therefore, when the steam discharge unit 180 is closed from the time when the stabilization check is completed, the internal pressure of the inner pot is lowered to an appropriate level during the stabilization check process, and thereafter, the proper level of pressure is maintained and the main body is caused by the inner pressure of the inner pot. There is no phenomenon that the lid does not open.

In addition, after the step (S11), (S13), and (S15) of performing the warming after cooking is performed, the step (S17) is not only performed, but also after the elapsed time determined in step (S19) is increased ( When the elapsed time determined in S21) is less than the reference elapsed time, the process proceeds to step S19. When the internal temperature of the inner pot is out of the reference range in step (S19) and sequentially proceeds to steps (S11), (S13), (S15), and (S17), and from step (S25), the open operating conditions are In the case of being generated and sequentially proceeding to step S11, step S13, step S15, and step S17, step S17 initializes the elapsed time of the previous determination when starting the stabilization check process, Calculation of elapsed time begins.

In addition, among the open operating conditions in step (S25), when the internal temperature of the inner pot is out of the reference range, for example, when the environmental temperature from the temperature sensing unit 150 is changed during the warming process (external environment) When it changes to a cold or hot state), the control unit 200 automatically compensates and changes the warming target temperature so that the internal temperature of the inner pot is out of the reference range.

In addition, when the inner pot lid is opened, it occurs, for example, when the user eats food or keeps other food in the inner pot, and the control unit 200 detects the operation of the handle of the electric cooker and opens the lid. Check it. In this case, the internal temperature of the inner pot will be changed by the external conditions.

In addition, when there is a user input through the input unit 140, it is an input directly related to the execution of the warming process and the change in the target temperature for keeping warm, for example, reheating of warming, variation of the target temperature, and canceling of keeping warm. .

In addition, when power is re-supplied after being cut off, the control unit 200 proceeds to step S11 or performs a standby state based on the internal temperature of the inner pot sensed by the temperature sensing unit 150 . If the internal temperature of the inner pot is below the warming process start temperature (eg, 50° C.), the controller 200 cancels the warming process and performs a standby process, and when the internal temperature of the inner pot exceeds the warming process start temperature, The control unit 200 proceeds to step S11 while performing the warming process to perform a stabilization confirmation process.

In addition, when the elapsed warming time is equal to at least one or more lower control times (eg, 4 hours, 8 hours, 12 hours, 16 hours, etc.) smaller than the reference control time, the control unit 200 performs step S11 ) to perform an opening operation of the steam discharge unit 200 . Since the parts in the steam discharging unit 180 are stuck due to a long heating operation performed during the closing operation of the steam discharging unit 180 , the control unit 200 uses these lower control times to schedule the opening operation. It is performed at time intervals to prevent sticking between the parts in the steam outlet 180 .

If any one of the five conditions in step S25 described above occurs, the process proceeds to step S11.

In the above-described steps (S11) to (S13), after the elapsed warming time is equal to or greater than the reference control time, the control unit 200 continuously maintains the opening operation of the steam discharging unit 180, so that the steam discharging unit ( 180) to prevent the problem of sticking between the parts in the

The heating target temperature or the warming output of the heating unit 130 (upper heating unit) during the opening operation of the above-described step S11 is the heating unit 130 during the closing operation of the step S23 in order to prevent water condensation. The upper heating part) is adjusted to be higher than the warming target temperature or the warming output.

5 is an example of a first and a second control signal to a vapor outlet.

During time (t0) - (t1), the control unit 200 generates a first control signal (off control signal) so that a voltage is not applied to the vapor discharge unit 180 to perform the opening operation of step S11 . and applied to the valve driving unit 160 .

From time t1, the control unit 200 is turned on so that a driving voltage of 20V is applied to the vapor discharge unit 180 during times t1 - t2 to perform the closing operation of step S23. A control signal is applied to the valve driving unit 160 , and a PWM control signal is applied to the valve driving unit 160 so that a voltage having a preset duty ratio is applied to the steam discharge unit 180 from time t2 to time t5 . do. That is, the second control signal is an on control signal for continuously applying a driving voltage to the steam discharge unit 180 for a reference time (eg, 2 seconds) to perform a closing operation of the steam discharge unit 180 and , and a PWM control signal for allowing a driving voltage corresponding to the duty ratio to be applied to the steam discharging unit 180 while the closing operation of the steam discharging unit 180 is maintained.

If a driving voltage of 20V is continuously applied to the steam discharge unit 180 during the closing operation of the steam discharge unit 180, a sticking problem between the parts in the steam discharge unit 180 may occur. For this purpose, a PWM control signal is used. The control unit 200 maintains the closing operation, for example, an on control signal (duty ratio 70%) (time (t2-t3)) (heating function operation) and an off control signal (duty ratio 30%) (time (t3) -t4)) (interruption of heating function) using the sequentially repeated PWM control signal, to stop the heating operation of the steam discharge unit 180 by the off control signal, so that the steam discharge unit 180 is in a high temperature state This solves the problem of sticking between parts in the vapor outlet 180 by preventing it from reaching. In addition, since the second control signal includes the off control signal, the control unit 200 prevents the steam discharging unit 180 from performing a heating operation during the OFF control signal, that is, periodically stopping the heating operation to discharge steam. The heating temperature of the unit 180 can be adjusted.

In addition, the duty ratio of the PWM control signal can be changed by the control unit 200 or by a user input from the input unit 140 . The basic duty ratio of the on control signal is set to 70%, but, for example, water in the inner pot upper region (the bottom portion of the inner pot lid 50 and the rear portion 52a of the communication groove 52 and the fixing portion 55) According to the amount of forming, the duty ratio of the PWM control signal is adjusted. When the amount of condensation in the upper region of the inner pot is large, by setting the duty ratio of the on control signal upward (eg, 90%), the heating temperature of the steam discharge unit 180 rises, thereby reducing the amount of condensation. Conversely, if there is no or little water condensation in the upper area of the inner pot or discoloration occurs on the upper side of the food, the duty ratio of the on control signal is set downward (for example, 50%) to lower the heating temperature of the steam discharge unit 180. Improve the thermal insulation quality.

When the control unit 200 controls the steam discharge unit 180 in the PWM control method, the cycle of the PWM control signal is as short as possible, for example, 1 ms, and the application time of the on control signal is the closing time of the steam discharge unit 180 . The operation is maintained longer than the limit time to prevent the steam discharging unit 180 from being opened while the steam discharging unit 180 performs a heating operation. Here, when the application time of the on control signal is less than the limit time, the steam discharge unit 180 is opened or the opening and closing operations of the steam discharge unit 180 are repeatedly performed to generate unnecessary noise, so that the control unit 200 ) allows the application time of the ON control time to be maintained over the limit time. In addition, the control unit 200 controls the duty ratio range of the on control signal such that the application time of the on control signal is equal to or longer than the limit time even when the user sets the duty ratio through the input unit 140 (eg, 50%- 90%) is guided through the display unit 120, and only the duty ratio included in the duty ratio range is settable.

From time t5 , the control unit 200 generates a first control signal so that no voltage is applied to the steam discharge unit 180 to perform the opening operation of step S11 , and applies the first control signal to the valve driving unit 160 .

6 is a view illustrating a position of a temperature measuring portion inside the electric cooker. In order to confirm the temperature distribution according to the present invention, while the electric cooker performs the warming process at room temperature, the bottom (position ①) of the inner pot lid 50 corresponding to the heater 65, and the upper heating unit (heater 65) ) of the lower surface (position②) of the inner pot lid 50 or the fixed portion 55 corresponding to the steam control unit 70 to which is not attached, and the intermediate position of the food accommodated in the inner pot 20 (position③) Measure each temperature. The temperature distribution is shown in Table 1 below.

location prior art 1
(No heating function) the present invention
-Duty ratio (100%) the present invention
-Duty ratio (70%) prior art 2
(No heating function) Keeping target temperature (74℃) Keeping target temperature (79℃) ① 79.9℃ 80.5℃ 79.5℃ 83.9℃ ② 72.2℃ 77℃ 75.3℃ 74.9℃ ③ 74.1℃ 74.2℃ 74.3℃ 74.1℃

In the electric cooker applied with the prior art 1 (there is no heating function in the steam outlet and the target temperature to keep warm (74 ℃)), since the temperature at position ② is significantly lower than the target keep temperature (74 ℃), water condensation in the upper area of the inner pot A phenomenon occurs, and the whitening phenomenon occurs by falling on the food.

In addition, in the electric cooker to which the prior art 2 (the steam outlet has no heating function and the target temperature (79°C)) is applied, the temperature of position ① is relatively high, so discoloration or rice dryness occurs.

In addition, in the electric cooker to which the duty ratio (100%) is applied, while performing a heat generating function during the closing operation of the steam discharge unit 180, the temperature of the upper area of the inner pot is increased to prevent water condensation, thereby increasing the thermal insulation quality. there is an effect However, the temperature in the steam discharging unit 180 increases due to the continuous heating operation of the steam discharging unit 180 , which may cause a problem of sticking between components inside the steam discharging unit 180 .

In addition, in the electric cooker to which the duty ratio (70%) is applied, while performing a heat generating function during the closing operation of the steam discharge unit 180, the temperature of position ② is higher than the temperature of position ③, so the water condensation in the upper area of the inner pot is prevented. It is possible to improve the whitening phenomenon caused by and increase the thermal insulation quality. In addition, the steam discharging unit 180 repeatedly performs a heating operation for a time equal to the duty ratio of the on control signal and stopping the heat generation for a time equal to the duty ratio of the off control signal, so that the temperature of the steam discharging unit 180 is By not being high, the problem of sticking between the parts in the vapor discharge unit 180 is solved.

7 is a view showing the position of the temperature measurement portion of the steam outlet. While the electric cooker according to the present invention performs the warming process at room temperature, the temperatures of the upper position (④) and the side position (⑤) of the steam discharge unit 180 are measured, and the measured temperatures are shown in Table 2 below. .

location Duty ratio (70%) Duty ratio (100%) ④ 76.1℃ 85.5℃ ⑤ 79.0℃ 90.1℃

In Table 2, when the duty ratio is 100%, since the continuous heating operation is performed without performing PWM control, the temperatures of positions ④ and ⑤ are about 10°C higher than when the duty ratio is 70%, respectively. That is, when the duty ratio is 70%, since the steam discharging unit 180 is relatively low temperature than when the duty ratio is 100%, the problem of sticking between the parts in the steam discharging unit 180 even when a long heat generating operation is performed during the closing operation. does not occur

As described above, the present invention is not limited to the specific preferred embodiments described above, and anyone with ordinary skill in the art to which the invention pertains can use various methods without departing from the gist of the present invention as claimed in the claims. It goes without saying that modifications are possible, and such modifications are intended to be within the scope of the claims.

110: power unit 120: display unit
130: heating unit 140: input unit
150: temperature sensing unit 160: valve driving unit
180: steam outlet 200: control unit

Claims (13)

an input unit for obtaining a user input;
a temperature sensing unit for sensing an internal or external temperature of the inner pot;
a heating unit for applying heat to the inner pot;
a steam discharge unit provided with a driving coil for receiving power to open and close the valve;
a valve driving unit for controlling application and blocking of voltage to the driving coil; While performing a cooking process and a warming process according to a user input through the input unit, the valve driving unit is controlled to open or close the steam discharging unit, and heat generation of the steam discharging unit is performed during the closing operation of the steam discharging unit Consists of a control unit that allows the operation to be performed,
The control unit determines the stabilization of the internal temperature based on the internal temperature sensed by the temperature sensing unit in the open state of the steam discharge unit, and when the internal temperature is stabilized, the closing operation of the steam discharge unit is performed Electric cooker, characterized in that. According to claim 1,
The control unit applies a first control signal for shutting off voltage for the opening operation of the steam outlet and a second control signal for supplying voltage or shutting off voltage for closing the vapor outlet to the valve driving unit. Features an electric cooker. 3. The method of claim 2,
The second control signal is a pulse composed of an ON control signal for supplying the voltage to the steam discharge unit so that the closing operation and the heating operation of the steam discharge unit are performed, and an OFF control signal for cutting off the voltage to the steam discharge unit Electric cooker comprising a width modulation (PWM) control signal. 4. The method of claim 3,
The second control signal includes an ON control signal for supplying a voltage to the steam outlet for a reference time before the pulse width modulation (PWM) control signal. 4. The method of claim 3,
The electric cooker, characterized in that the application time of the on control signal is set to be more than a limit time so that the closing operation of the steam discharging unit is maintained. 4. The method of claim 3,
The electric cooker sets a duty ratio of an ON control signal of the pulse width modulation (PWM) signal so that the closing operation of the steam discharge unit is maintained. an input unit for obtaining a user input;
a temperature sensing unit for sensing an internal or external temperature of the inner pot;
a heating unit for applying heat to the inner pot;
a steam discharge unit provided with a driving coil for receiving power to open and close the valve;
a valve driving unit for controlling application and blocking of voltage to the driving coil; While performing a cooking process and a warming process according to a user input through the input unit, the valve driving unit is controlled to open or close the steam discharging unit, and heat generation of the steam discharging unit is performed during the closing operation of the steam discharging unit Consists of a control unit that allows the operation to be performed,
The control unit is an electric cooker, characterized in that by adjusting the heating target temperature or the warming output of the heating unit during the opening operation of the steam discharging unit to be higher than the target keeping temperature or the warming output of the heating unit during the closing operation of the steam discharging unit. an input unit for obtaining a user input;
a temperature sensing unit for sensing an internal or external temperature of the inner pot;
a heating unit for applying heat to the inner pot;
a steam discharge unit provided with a driving coil for receiving power to open and close the valve;
a valve driving unit for controlling application and blocking of voltage to the driving coil; While performing a cooking process and a warming process according to a user input through the input unit, the valve driving unit is controlled to open or close the steam discharging unit, and the steam discharging unit generates heat when the steam discharging unit closes. Consists of a control unit that allows the operation to be performed,
The control unit calculates the elapsed time of the warming process, and when the calculated elapsed time of keeping warm is equal to or greater than the reference control time, the electric cooker continuously maintains the opening operation of the steam discharging unit. According to claim 1,
The control unit calculates a judgment elapsed time when the internal temperature is equal to the warming target temperature, and when the internal temperature is within a reference range until the calculated elapsed judgment time is greater than or equal to the reference elapsed time, the internal temperature is stabilized Electric cooker, characterized in that it is determined to be. According to claim 1,
The control unit determines whether an opening operation condition of the steam discharging unit occurs while the closing operation of the steam discharging unit is performed in the warming process. 11. The method of claim 10,
The opening operation condition of the steam discharge part is when the internal temperature is out of a reference range, when the lid of the electric cooker is opened, when there is a user input through the input unit, when the power is re-supplied after being cut off, and the elapsed time of keeping warm The electric cooker, characterized in that it includes at least one of the case of being equal to at least one or more lower control times smaller than the reference control time. 11. The method of claim 10,
The control unit causes the opening operation of the steam discharging unit to be performed when the opening operation condition of the steam discharging unit occurs, and re-determining stabilization of the internal temperature based on the internal temperature. 12. The method of claim 11,
The user input is an electric cooker, characterized in that it includes at least one or more of reheating, changing the target temperature, and canceling the keeping warm.

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