KR20170000915A - Electric cooker - Google Patents

Abstract

The present invention relates to an electric cooker using heating characteristics of a driving coil installed in a steam discharge unit, so as to minimize a temperature difference of an inner pot lid part when an insulation process is performed. According to the present invention, the electric cooker comprises: an input unit acquiring a user input; a temperature detection unit detecting an internal or external temperature of an inner pot; a heating unit applying heat to the inner pot; the steam discharge unit including the driving coil receiving power to perform opening/closing operation; a valve operation unit controlling application and cut-off of voltage supplied to the driving coil; and a control unit controlling the valve operation unit to perform the opening/closing operation of the steam discharge unit and performing a heating operation of the steam discharge unit during the closing operation of the steam discharge unit while performing a cooking process and the insulation process according to the user input through the input unit.

Description

ELECTRIC COOKER

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 a heating characteristic of a driving coil provided in a steam discharging portion.

The electric cooker is a device that cooks food by making the inside of the inner pot heated to a high temperature and high pressure by containing the food material to be cooked in the inner pot. Such an electric cooker is often used as an electric rice cooker, but in recent years, it has been widely used as an electric cooker to cook various kinds of food in addition to rice.

The basic structure of a general electric cooker is composed of a main body, an inner pot accommodated in the main body, and a main lid covering the upper portion of the main body. The main body has heating means for heating the inner pot, and the main body lid is provided to open and close the upper portion of the main body.

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

1 and 2, the conventional lid of the electric cooker includes a lid 40 for opening and closing an upper portion of a main body (not shown), and a lid 40 for detachably attaching to the lower end of the lid 40 An inner pot lid 50 and a top plate 60, which are provided.

In the top plate 60, the steam adjusting portion 70 is seated and engaged in the receiving groove 62 for adjusting the steam in the inner pot. The steam adjusting unit 70 includes an automatic steam discharging unit 90 for discharging the steam from the inner pot when the inner pressure of the inner pot becomes equal to or higher than a predetermined pressure and an automatic steam discharging unit 90 for discharging steam from the inner pot during the cooking process or after completion of the cooking process A communication hole communicating with the steam discharging portion 80 (solenoid valve device) for discharging the steam, the automatic steam discharging portion 90 and the steam discharging portion 80 is formed, and the automatic steam discharging portion 90 and the steam discharging portion And a fixing plate 72 on which the fixing plate 80 is mounted.

A heater 65 is attached to an upper surface of the top plate 60 except for the receiving groove 62 and is coupled to the lower surface of the lid 40. The inner lid 50 is fixed to the top plate 60 As shown in Fig.

The heater 65 is not attached to the fixing plate 72 because the automatic steam discharging unit 90 and the steam discharging unit 80 are mounted on the fixing plate 72 and the fixing plate 72 is coupled to the receiving groove 62. Therefore, The communicating groove 52 of the inner lid 50 corresponding to the bottom surface of the receiving groove 62 and the receiving groove 62 is not in direct contact with the heater 65. [ Due to such a structural problem, water is supplied to the bottom surface portion of the inner pot lid 50, the back surface portion 52a of the communication groove 52, and the fixing portion 55 corresponding to the area where the heater is not provided, And the water thus formed falls into the rice inside the inner pot, and the rice turns white and becomes watery, causing bleaching which is a cause of deterioration in the quality of the thermal insulation.

Such a whitening phenomenon is caused not only by the inner pot lid separating type electric cooker as shown in Figs. 1 and 2 but also by the electric cooker in which the inner pot lid is not separated. Further, in order to solve the whitening phenomenon, it is possible to mount a separate heating device on the portion where the heater is not provided, but it is necessary to install the heating device and add a process, and the heating device is corroded by the steam, Loss or burnout may occur.

Further, in the conventional electric cooker, when the steam discharging part 80 is closed for a long time in the warming step, the pressure in the inside increases, and the main body lid is not opened.

The present invention provides an electric cooker that minimizes a temperature difference in a lid portion of an inner pot by using a heating characteristic of a driving coil provided in a steam discharging portion during a warming process and adjusts a heating temperature of a driving coil by using a PWM control method The purpose.

Further, the present invention provides an electric cooker that maintains the internal pressure of the inner pot at an appropriate level by keeping the steam discharging part in a closed state after the internal temperature is stabilized based on the internal temperature of the inner pot The purpose.

The electric cooker of the present invention includes an input unit for obtaining a user input, a temperature sensing unit for sensing the temperature inside or outside the inner pot, a heating unit for heating the inner pot, and a control unit A valve driving unit for controlling the application and blocking of the voltage to the driving coil; a cooking process according to user input through the input unit; and a controller for controlling the valve driving unit, And a control unit for performing an opening or closing operation of the steam discharging unit and performing a heating operation of the steam discharging unit during a closing operation of the steam discharging unit.

The control unit may be configured to apply a first control signal for performing a voltage cutoff for the operation of opening the vapor discharge unit and a second control signal for performing a voltage supply or a voltage cutoff for the closing operation of the vapor discharge unit to the valve driving unit .

The second control signal may include an ON control signal for supplying the voltage to the steam discharging unit so that the closing operation and the heating operation of the steam discharging unit are performed, and an OFF control signal for blocking the voltage to the steam discharging unit And preferably comprises a configured pulse width modulation (PWM) control signal.

Preferably, the second control signal includes an on-control signal for supplying a voltage to the steam discharging unit during 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 be equal to or greater than a time limit so that the closing operation of the vapor discharger is maintained.

Preferably, the control unit estimates the elapsed time of the warming-up process and continuously maintains the opening operation of the steam discharging unit when the estimated warming-up time exceeds the reference control time.

The control unit may determine the stabilization of the internal temperature based on the internal temperature sensed by the temperature sensing unit in the open state of the steam discharging unit. When the internal temperature is stabilized, .

The present invention minimizes the temperature difference of the inner lid part by using the heating characteristics of the driving coils provided in the steam discharging part during the warming process to improve whitening and improve the quality of insulation, By controlling the temperature, there is an effect of solving the sticking problem between the parts in the steam discharging part.

Further, the present invention can reduce the temperature difference of the inner pot lid portion, reduce the heating amount by the heating portion, and maintain the food within the desired keeping temperature range, thereby reducing power consumption.

Further, in the present invention, after the inner temperature is stabilized on the basis of the inner temperature of the inner pot, the inner pressure of the inner pot is maintained at a proper level by keeping the steam discharging portion in a closed state during the warming process, There is an effect that a problem that the lid is not opened due to the internal pressure when it is opened can be solved.

Further, in the present invention, in the warming process, when the steam discharging unit is kept closed, the steam discharging unit is opened at regular time intervals, and when the warming operation is performed over the reference control time, the steam discharging unit is continuously opened, There is an effect of solving the sticking problem between the two.

1 is an exploded perspective view of a body lid of a conventional electric cooker.
2 is an exploded perspective view showing a state in which an inner lid is detached from a lid of a main body of a conventional electric cooker.
3 is a configuration diagram of the electric cooking apparatus according to the present invention.
Fig. 4 is a control flowchart of the electric cooker of Fig. 3; Fig.
FIG. 5 is a graph showing examples of the voltages at both ends of the vapor discharge portion according to the first and second control signals.
6 is a view showing the position of a temperature measuring part inside the electric cooker.
7 is a view showing the position of the temperature measurement part of the vapor discharge part.

Hereinafter, the present invention will be described in detail with reference to the embodiments and the drawings.

3 is a configuration diagram of the electric cooking apparatus according to the present invention. The electric cooker includes a power supply unit 110 for supplying power required by a commercial power supply, a display unit 120 for displaying a menu or a current cooking process, a heating unit for heating the upper, An input unit 140 for receiving a menu selection, a cooking process, a duty ratio selection of a PWM signal, etc. from the user, and an input unit 140 for continuously sensing an inner temperature of the inner pot and / A valve driving unit 160 for receiving a control signal from the control unit 200 and applying a voltage to the steam discharging unit 180, a steam discharging unit 160 for discharging steam discharged from the valve driving unit 160, A controller 180 for controlling the above components to perform an atmospheric process, a cooking process, a warming process, and the like, and controlling the application of a voltage to the steam discharger 180 to perform an opening / 200).

The power source unit 110, the display unit 120, the input unit 140, and the temperature sensing unit 150 correspond to a technology of a degree recognizable to a person of ordinary skill in the art , The description thereof is omitted. The present invention also includes the devices shown in Figs.

The heating unit 130 includes an upper heating unit (identical to the heater 65 in FIG. 1) mounted on the lid for heating the upper side of the inner pot, a side heating unit for heating the side surface of the inner pot, As shown in Fig.

The valve driving unit 160 receives the control signal from the control unit 200 and controls the voltage to the steam discharging unit 180 according to the control signal. The steam discharging unit 180 includes a driving coil for driving and discharging the steam by opening the valve (opening and closing of the valve) by receiving the voltage. The control unit 200 controls the above-described components to perform a waiting process, performs a cooking process by a menu selection and a start command for cooking, performs a warming process after the cooking process, Follow the command to perform the warming process. The control unit 200 controls the valve driving unit 160 to perform the opening and closing operations of the steam discharging unit 180 according to the processes performed while performing the atmospheric process, the cooking process, the warming process, and the like.

In this embodiment, the control signal includes a first control signal for the open operation of the vapor discharge section 180, and a second control signal for the closed operation of the vapor discharge section 180. In response to the first control signal, the valve driving unit 160 does not supply any additional power to the steam discharging unit 180 to perform only the opening operation and does not perform the heating operation. In response to the second control signal, 180 so that the driving coil in the steam discharging unit 180 performs a heating operation. The control unit 200 uses the second control signal including the PWM (Pulse Width Modulation) control signal to use the heat generation characteristic in which the drive coil generates heat during the closing operation of the vapor discharge unit 180 in the thermal insulation process, The contents are described below.

The control unit 200 determines whether the inner temperature of the inner pot is stabilized using the inner temperature of the inner pot sensed by the temperature sensing unit 150 in the open state of the steam exhaust unit 180 while performing the warming process , The steam discharging unit 180 is maintained in the closed state after the internal temperature of the inner pot is stabilized, so that the internal pressure of the inner pot is controlled to be maintained at an appropriate level. The matters relating to this internal pressure control are described in detail below.

Fig. 4 is a control flow chart of the electric cooker of Fig. 3, and Fig. 5 are examples of both end voltages of the vapor discharge portion 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 sensed by the temperature sensing unit 150 according to the cooking algorithm, . After the completion of the cooking process, the controller 200 automatically performs the warming process or performs the warming-up process according to the warming-up command from the input unit 140 (S11). In addition, the control unit 200 calculates the time elapsed from the execution of step S11 to the end of the insulation maintaining process.

In step S11, the controller 200 generates a first control signal and applies the first control signal to the valve driving unit 160. The valve driving unit 160 controls the opening operation of the steam discharging unit 180 in response to the first control signal . Since the temperature of the fixing plate 72 on which the steam discharging unit 180 is mounted is lowered and water is formed, the controller 200 does not perform the heating operation during the opening operation, (Or the upper heating portion of the heating unit 130) to prevent water from being formed in the heating unit 130 and the heating output.

In step S13, the control unit 200 compares the calculated thermal insulation elapsed time with the stored reference control time. If the calculated thermal insulation time is equal to or greater than the reference control time, the process proceeds to step S11 to maintain the open operation, and otherwise proceeds to step S15.

 This reference control time corresponds to a time for preventing sticking problems in the steam discharging unit 180, and is set to, for example, 20 hours. In step S23 of the control flow chart, the steam discharging 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, (For example, a valve body formed with a steam inlet opening communicating with the inside of the electric cooker, a diaphragm for opening and closing the steam inlet, etc.) to perform the closing operation at a high temperature, Are prevented from being delayed or opened due to sticking to each other. In order to solve the fixing problem due to the heating operation during the closing operation, the controller 200 proceeds to step S11 if the heating elapsed time is equal to or greater than the reference control time, and the steam discharging unit 180 maintains the opening operation So that the heat generating operation is interrupted to prevent sticking of components in the steam discharging unit 180. [

In step S15, the controller 200 determines whether the inner temperature of the inner pot detected by the temperature sensing unit 150 is equal to the thermal insulation target temperature. If the inner temperature of the inner pot is equal to the keeping target temperature, the process proceeds to step S17, and if not, the process proceeds to step S11.

In step S17, the control unit 200 starts calculating the elapsed time of judgment or initializes the elapsed time of the judgment to determine the stabilization of the inner temperature of the inner pot, and then proceeds to step S19.

In step S19, the controller 200 determines whether the inner temperature of the inner pot is within the reference range while increasing the elapsed time of the judgment. If the internal temperature of the inner pot is within the reference range, the process proceeds to step S21; otherwise, the process proceeds to step S11. The reference range is, for example, a temperature range from the lower limit temperature (heating target temperature -4 DEG C) to the upper limit temperature (heating target temperature + 4 DEG C), and the reference range can be varied. Further, when the keep warming target temperature is variable, the lower limit temperature and the upper limit temperature of the reference range can be varied.

In step S21, the control unit 200 determines whether the elapsed time of judgment is greater than or equal to the reference elapsed time. If the judgment elapsed time is equal to or larger than the reference elapsed time, the process proceeds to step S23, and if not, the process proceeds to step S19. The reference elapsed time corresponds to a time for judging whether or not the internal temperature of the inner pot is stabilized, and is set to, for example, 10 minutes.

In step S23, the controller 200 generates a second control signal including a PWM signal and applies the second control signal to the valve driving unit 160. In response to the second control signal, the valve driving unit 160 applies the control signal to the steam discharging unit 180 ) And the heat-generating operation are performed. The control unit 200 can control the closing operation of the vapor discharger 180 and the heating temperature (or heating value) in the heating operation by using the second control signal. This point will be described in detail below with reference to FIG. The control unit 200 controls the temperature of the heating unit 130 (or the upper heating unit of the heating unit 130) or the heating output Down.

In step S25, the control unit 200 determines whether an open operating condition of the steam discharging unit 180 occurs. If an open operating condition occurs, the process proceeds to step S11, and if not, the process proceeds to step S27. Here, the opening operation condition is such that when the inner 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 cut off and then supplied again, And equal to at least one or more lower control times, and the matters of the open operating condition are described in detail below.

In step S27, the control unit 200 determines whether the user inputs the end of the warming-up process through the input unit 140. [ If the end of the warming-up process has been input, the control for the vapor discharger 180 is terminated, and if not, the process proceeds to step S23.

Through the above-described steps S15 to S21, the control unit 200 determines that the judgment elapsed time while the internal temperature of the inner pot is continuously maintained within the reference range while performing the warming process is equal to or greater than the reference elapsed time If it is determined that the internal temperature of the inner pot has stabilized, the operation of opening the steam discharging part 180 is performed in step S11, and if it is not stabilized, And performs a closing operation and a heating operation of the unit 180. [ The stabilization confirmation process before the closing of the steam discharging unit 180 is required because the inner pressure of the inner pot is increased when the steam discharging unit 180 is closed at the completion of the cooking so that the lid of the main body is not opened, This is because the increased internal pressure of the inner pot is maintained even when the inner temperature of the inner pot is lowered, and the lid of the main body is not opened. Accordingly, when the steam discharging unit 180 is closed from the time when the stabilization confirmation is completed, the inner pressure of the inner pot is lowered to an appropriate level during the stabilization check process, and the appropriate level of pressure is maintained thereafter, The phenomenon that the lid is not opened does not occur.

In addition to the case of proceeding to step S17 after the step S11, step S13 or step S15 of performing the keeping warm-up after the cooking is performed, as well as the case where the judgment elapsed time is increased in step S19, S21), the process proceeds to step S19 when the judgment elapsed time is less than the reference elapsed time. When the internal temperature of the inner pot is out of the reference range in step S19 and the process proceeds sequentially to step S11, step S13, step S15 and step S17 and step S25, In step S17, when the stabilization confirmation process is started, the previous determination elapsed time is initialized, and when the stabilization confirmation process is started, Start to calculate elapsed time.

When the inner temperature of the inner pot is out of the reference range in the open operation condition in step S25, for example, if the ambient temperature from the temperature sensing unit 150 is changed during the warming process The control unit 200 automatically compensates for the heating target temperature so that the inner temperature of the inner pot deviates from the reference range.

When the lid of the inner pot is opened, for example, the user may store the food in the inner pot to eat the food or to store the other food in the inner pot. The controller 200 senses the operation of the handle of the electric cooker and opens the lid Check. In this case, the inner temperature of the inner pot will be changed by external conditions.

In the case where there is a user input through the input unit 140, the input related directly to the execution of the warming process and the change in the warming target temperature corresponds to, for example, warming reheating, variable heating target temperature, .

In addition, when the power is turned off and then supplied again, the controller 200 proceeds to step S11 or performs a standby state based on the inner temperature of the inner pot detected by the temperature sensing unit 150. [ If the inner temperature of the inner pot is lower than the starting temperature of the thermal process (for example, 50 ° C), the controller 200 cancels the thermal process and performs the waiting process. If the inner temperature of the inner pot exceeds the thermal process start temperature, The controller 200 proceeds to step S11 while performing the warming process to perform the stabilization check process.

Further, when the warming-up elapsed time becomes equal to at least one or more lower control times (for example, 4 hours, 8 hours, 12 hours, 16 hours, etc.) smaller than the reference control time, And performs an opening operation of the steam discharging unit 200. [ The control unit 200 controls the opening operation to be performed in a predetermined period of time using the lower control times because the components in the steam discharging unit 180 are stuck due to the heating operation for a long time performed during the closing operation of the steam discharging unit 180. [ So as to prevent sticking between the parts in the steam discharging part 180. [

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

The control unit 200 continuously maintains the opening operation of the steam discharging unit 180 so that the steam is discharged from the steam discharging unit (not shown) 180 are prevented from being adhered to each other.

The heating target temperature and the heating output of the heating unit 130 (upper heating unit) during the opening operation of the above-described step S11 are set so that the heating unit 130 ( The heating target temperature and the heating output of the upper heating unit).

5 is an illustration of the first and second control signals to the steam outlet.

During the time t0 to t1, the control unit 200 generates a first control signal (an off control signal) so that the voltage is not applied to the vapor discharger 180 in order to perform the opening operation in step S11 And applies it to the valve driving unit 160.

The control unit 200 turns on the drive voltage of 20V for the time t1 to t2 to be applied to the vapor discharge unit 180 in order to perform the closing operation of the step S23 from the time t1, 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 predetermined duty ratio from the time t2 to the time t5 is applied to the vapor discharging unit 180 do. That is, the second control signal is a control signal for causing the driving voltage to be continuously applied to the steam discharging unit 180 for a predetermined time (for example, 2 seconds) so that the closing operation of the steam discharging unit 180 is performed And a PWM control signal for causing a driving voltage corresponding to the duty ratio to be applied to the vapor discharge unit 180 while the closing operation of the vapor discharge unit 180 is maintained.

If a driving voltage of 20 V is continuously applied to the steam discharging unit 180 during the closing operation of the steam discharging unit 180, a problem of sticking between parts in the steam discharging unit 180 may occur, The PWM control signal is used. (Duty ratio of 30%) (time t3 (duty ratio)) (time t2-t3) (heat generation function operation) while maintaining the closing operation, the heating operation of the steam discharging unit 180 is stopped by the OFF control signal by using the PWM control signal in which the heating operation is intermittently repeated So that the fixing problem between the parts in the steam discharging part 180 is solved. In addition, since the second control signal includes the OFF control signal, the controller 200 prevents the steam discharging unit 180 from performing the heating operation during the OFF control signal, i.e., periodically stops the heating operation, The heat generation temperature of the unit 180 can be controlled.

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 bottom surface portion of the inner pot lid 50 and the back surface portion 52a of the communication groove 52 and the fixing portion 55) of the inner pot lid 50 is set to 70% The duty ratio of the PWM control signal is adjusted in accordance with the amount of the PWM control signal. (For example, 90%) by increasing the duty ratio of the on control signal, the heat generation temperature of the steam exhaust part 180 rises and the water intake amount is reduced. (For example, 50%) of the on-control signal is lowered to lower the heat generation temperature of the steam discharging unit 180 when the water in the upper area of the inner pot is free or less water- Improve thermal insulation quality.

When the control unit 200 controls the steam discharging unit 180 in a PWM control method, the cycle of the PWM control signal is set to be as short as possible, for example, 1 ms, and the on- So that the steam discharging unit 180 is not opened while the steam discharging unit 180 performs the heating operation. When the ON control signal is applied for less than the predetermined time, the steam discharging unit 180 is opened or the opening and closing operations of the steam discharging unit 180 are repeatedly performed to generate unnecessary noise. ) Causes the application time of the on control time to be maintained above the limit time. In addition, the control unit 200 may set the duty ratio range (e.g., 50% -50%) of the ON control signal so that the ON control signal application time exceeds the limit time even when the user sets the duty ratio through the input unit 140. [ 90%) through the display unit 120 so that only the duty ratio included in the duty ratio range can be set.

From time t5, the controller 200 generates the first control signal so as not to apply the voltage to the steam discharger 180 and applies the first control signal to the valve driver 160 to perform the opening operation of step S11.

6 is a view showing the position of a temperature measuring part inside the electric cooker. (Position 1) of the inner pot lid 50 corresponding to the heater 65 and the bottom surface (position 1) of the inner pot lid 50 corresponding to the heater 65 and the upper heating portion (the heater 65) during the warming process at room temperature, (Position 2) of the inner pot lid 50 or the bottom surface of the fixing portion 55 corresponding to the steam adjusting portion 70 to which the inner pot 20 is not attached and the bottom surface The temperature is measured individually. The temperature distribution is shown in Table 1 below.

location Prior art 1
(No heat generation function) Invention
- duty ratio (100%) Invention
- duty ratio (70%) Prior Art 2
(No heat generation function) Heat insulation target temperature (74 ℃) Keep target temperature (79 ℃) ① 79.9 ° C 80.5 DEG C 79.5 DEG C 83.9 ° C ② 72.2 DEG C 77 ℃ 75.3 DEG C 74.9 ° C ③ 74.1 DEG C 74.2 DEG C 74.3 DEG C 74.1 DEG C

In the electric cooker according to the prior art 1 (in which the steam discharging part has no heating function and the heating target temperature (74 ° C)) is applied, the temperature at the position 2 is considerably lower than the heating target temperature (74 ° C) A phenomenon occurs, and the cooked food falls on the cooked food, causing a whitening phenomenon.

Further, in the electric cooker of the prior art 2 in which the target temperature of the heating target is adjusted upward (the target temperature for heating (79 캜) without the heat generating function in the steam discharging portion) is applied, the temperature of the position ① becomes relatively high, Drying occurs.

Further, in the electric cooker having the duty ratio (100%) applied while performing the heating function during the closing operation of the steam discharging unit 180, the temperature of the upper area of the inner pot is raised to prevent the water condensation phenomenon, There is an effect. However, due to the continuous heating operation of the steam discharging unit 180, the temperature in the steam discharging unit 180 may be increased, and the fixing problem between the parts inside the steam discharging unit 180 may be caused.

Further, in the electric cooker to which the duty ratio (70%) is applied, the temperature of the position (2) is higher than the temperature of the position (3) while performing the heat generating function in the closing operation of the steam discharging unit (180) It is possible to improve the whitening phenomenon and improve the quality of insulation. In addition, the steam discharging unit 180 repeatedly performs the heating operation for a period of time corresponding to the duty ratio of the ON control signal and the heating operation for a time corresponding to the duty ratio of the OFF control signal, The problem of sticking between parts in the vapor discharging part 180 is solved.

7 is a view showing the position of the temperature measurement part of the vapor discharge part. The temperature of the upper position (4) and the side position (5) of the steam discharging unit (180) is measured while the electric cooker according to the present invention performs the warming process at room temperature, and the measured temperature is as shown in Table 2 below .

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

In Table 2, when the duty ratio is 100%, the PWM control is not performed and the continuous heating operation is performed. Therefore, the temperatures of the positions 4 and 5 are each about 10 DEG C higher than the case where the duty ratio is 70%. That is, when the duty ratio is 70%, the steam discharging unit 180 is relatively lower in temperature than the case where the duty ratio is 100%. Therefore, even if the heating operation is performed during the closing operation for a long time, .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims. It is to be understood that modifications are possible and that such modifications are within the scope of the claims.

110: power supply unit 120: display unit
130: heating section 140: input section
150: temperature sensing unit 160: valve driving unit
180: Vapor discharge unit 200:

Claims (13)

An input unit for acquiring a user input;
A temperature sensing unit for sensing a temperature inside or outside the inner pot;
A heating unit for heating the inner pot;
A steam discharging unit having a driving coil for receiving a power and performing an opening and closing operation of the valve;
A valve driving unit for regulating application and interruption of voltage to the driving coil; Wherein the control unit controls the valve driving unit to perform an opening or closing operation of the steam discharging unit while performing a cooking process according to user input through the input unit and a warming process, And a controller for controlling the operation of the electric cooker. The method according to claim 1,
The control unit applies a first control signal for performing a voltage cutoff for the opening operation of the vapor discharge unit and a second control signal for performing a voltage supply or a voltage cutoff for the closing operation of the vapor discharge unit to the valve driving unit Features an electric cooker. 3. The method of claim 2,
The second control signal is a pulse including a control signal for supplying the voltage to the steam discharger so as to perform the closing operation and the heating operation of the steam discharging unit and an off control signal for cutting off the voltage to the steam discharging unit Width modulation (PWM) control signal. The method of claim 3,
Wherein the second control signal comprises an on control signal that causes a voltage to be applied to the vapor discharge during a reference time before the pulse width modulation (PWM) control signal. The method of claim 3,
Wherein the application time of the on-control signal is set to be equal to or longer than a time limit so that the closing operation of the steam discharging unit is maintained. The method of claim 3,
Wherein the electric cooker sets the duty ratio of the on-control signal of the pulse width modulation (PWM) signal so that the closing operation of the steam discharging unit is maintained. The method according to claim 1,
Wherein the control unit controls the heating target temperature or the heating output of the heating unit to be higher than the heating target temperature or the heating output of the heating unit during the closing operation of the steam discharging unit during the opening operation of the steam discharging unit. The method according to claim 1,
Wherein the control unit estimates the elapsed time of the warming step and continuously maintains the opening operation of the steam discharging unit when the estimated warming-up time exceeds the reference control time. The method according to claim 1,
The control unit may determine the stabilization of the internal temperature based on the internal temperature sensed by the temperature sensing unit in the open state of the steam exhaust unit, and may perform the closing operation of the steam exhaust unit when the internal temperature is stabilized And an electric cooking appliance. 10. The method according to any one of claims 1 to 9,
Wherein the control unit determines whether an opening operation condition of the steam discharging unit has occurred during the closing operation of the steam discharging unit. 11. The method of claim 10,
The opening operation condition of the steam discharging portion may be such that when the internal temperature is out of the reference range, when the lid of the electric cooker is opened, when there is a user input through the input unit, And the time is equal to at least one or more lower control times smaller than the reference control time. 12. The method of claim 11,
Wherein the controller is configured to perform the opening operation of the steam discharging unit when the opening operation condition of the steam discharging unit is generated, and determine the stabilization of the internal temperature again. 12. The method of claim 11,
Wherein the user input includes at least one of a heating reheat, a variable temperature target temperature, and a temperature cancellation input.

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