KR101707881B1 - Induction cooker having container detecting function and container detecting method of induction cooker - Google Patents

Abstract

The induction heating cooker having a container recognizing function according to the present invention includes: a DC power generating unit for receiving a commercial power source and rectifying the DC power to generate a DC voltage; An input current measuring unit for measuring a current flowing in the DC power generator; An input voltage measuring unit for measuring a voltage value of the direct current voltage generated by the direct current power generator; A switching unit for turning on / off the application of the DC voltage to the working coil; And high frequency control of the operation of the switching unit to inductively heat the cooking vessel disposed in the vicinity of the working coil, and using the current value measured by the input current measuring unit and the voltage value measured by the input voltage measuring unit And determines that the cooking container is not positioned within the allowable range of the working coil when the current power value becomes lower than a predetermined reference value.

Description

TECHNICAL FIELD [0001] The present invention relates to an induction heating cooker having a container recognition function and a container recognition method for the induction heating cooker having a container recognition function.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker, and more particularly, to an induction heating cooker having a container recognition function capable of detecting whether a container is normally heated, and a container recognition method in such an induction heating cooker.

BACKGROUND ART [0002] Recently, an electric cooker for induction heating a container by using a working coil has been popularized. Such an induction heating cooker is optimized for an electric conductor or a container made of a semiconductor material.

Therefore, if the container is not positioned above the working coil, or if a container made of a material that can not be induction-heated is located above the working coil, it should be sensed to control the output of the cooker.

A conventional technique for detecting whether or not the container is positioned on the upper portion of the working coil is disclosed in Japanese Laid-Open Patent Publication No. 2012-87483 (Aug. 27, 2012). In the above-described prior art, the presence or absence of the container is determined by sensing the magnetic force reaction caused by the iron component of the container positioned on the upper surface of the electric cooking stove body.

However, since it is only possible to detect the container around the sensor by the magnetic force reaction, there is a problem in that a plurality of sensors must be disposed if it is desired to detect the presence or absence of the container with respect to the entire area occupied by the working coil have.

Open Patent Publication No. 2012-87483 (Aug. 27, 2012)

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention aims to provide an induction heating cooker capable of determining whether a container is correctly placed on a working coil by a simple principle and configuration.

It is also intended to provide an induction heating cooker capable of determining the presence or absence of a container without disposing a plurality of sensors.

According to an aspect of the present invention, there is provided an induction heating cooker having a container recognition function, comprising: a DC power generator for generating a DC voltage by receiving a commercial power; An input current measuring unit for measuring a current flowing in the DC power generator; An input voltage measuring unit for measuring a voltage value of the direct current voltage generated by the direct current power generator; A switching unit for turning on / off the application of the DC voltage to the working coil; And high frequency control of the operation of the switching unit to inductively heat the cooking vessel disposed in the vicinity of the working coil, and using the current value measured by the input current measuring unit and the voltage value measured by the input voltage measuring unit And determines that the cooking container is not positioned within the allowable range of the working coil when the current power value becomes lower than a predetermined reference value.

In this case, the input current measuring unit measures the current value of the commercial power source which is not rectified at the previous stage of the rectifying circuit of the DC power generating unit, and the input voltage measuring unit measures the current value of the DC power rectified at the rear end of the rectifying circuit of the DC power generating unit Measure the voltage value of the voltage.

The microcomputer may store the current power value measured after the commercial power is first input as an initial reference value and if the current power value measured in real time becomes lower than the initial reference value, It is determined that the cooking vessel is not positioned.

Further, the microcomputer maintains the maximum value of the current power measured, and when the measured current power value is lower than a predetermined ratio of the maintained maximum value, the microwave compartment is positioned within the allowable range of the working coil It is judged that it is not performed.

According to another aspect of the present invention, there is provided a method of driving a DC / DC converter, the method comprising: rectifying a commercial power source to apply a generated DC voltage to a working coil by high frequency switching; Calculating a current power value using a current value of the commercial power source and a rectified voltage value of the DC voltage; And judging that the cooking container is not positioned within the allowable range of the working coil if the current power value drops and satisfies a predetermined condition.

Wherein the determining step comprises: storing the current power value measured after the commercial power is first input as an initial reference value; if the current power value measured in real time becomes lower than the initial reference value, And determining that the cooking vessel is not positioned within the allowable range.

Further, the determining may further include: maintaining a maximum value of the current power value to be measured; if the measured current power value is lower than a predetermined ratio of the maintained maximum value, And determining that the container is not positioned.

According to the induction heating cooker and the container recognition method of the present invention having the container recognition function according to the present invention, it is possible to precisely determine whether the container is positioned in the vicinity of the working coil without adding a separate sensor for container sensing .

Further, since it is not specialized to detect the container only in a part of the area of the working coil, the presence or absence of the container can be efficiently detected.

1 is a block diagram schematically illustrating a configuration of an induction heating cooker having a container recognition function according to an embodiment of the present invention.
2 is a circuit diagram for explaining a configuration of an input current measuring unit and an input voltage measuring unit in an induction heating cooker having a container recognition function according to an embodiment of the present invention.
3 is a flowchart illustrating a container recognition method in an induction heating cooker according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a container recognition method of an induction heating cooker and an induction heating cooker having a container recognition function according to the present invention will be described with reference to the accompanying drawings. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting.

First, a configuration of an induction heating cooker having a container recognition function according to an embodiment of the present invention will be schematically described with reference to FIG. A general induction heating cooker includes a DC power generating unit 20, a switching unit 30, a working coil 40, and a micom 50.

The working coil 40 may be disposed at the bottom of the top plate on which the container 42 in which the object to be cooked can be placed is placed and is in the form of a coil wound in a spiral form. When the high-frequency current is applied, the working coil 40 emits an electromagnetic force due to its inductance, and this electromagnetic force inductively induces the container 42 itself placed on the upper plate.

The working coil 40 may be configured to enclose the side surface or the upper surface of the container 42.

The DC power generator 20 receives a commercial power supply 10 (for example, 110 to 220 V household AC power) and converts it into a DC voltage or a DC current for the purpose of applying the DC power to the working coil 40 . The converted direct current (in one embodiment, the working coil can be operated in a current resonant manner, in this case, applying a direct current) is applied to the working coil, resulting in induction heating of the vessel.

The switching unit 30 applies the DC current generated by the DC power generating unit 20 to the working coil 40 while turning on and off the high frequency corresponding to the high frequency control signal provided by the microcomputer. The high frequency on / off DC current is a resonance current, the energy of which is released from the working coil 40 by an electromagnetic force and applied to the vessel 42.

The microcomputer unit 50 is provided with a microcomputer 50 for driving the walking coil 40 at a specific heating intensity (for heating the container) in response to a user operation input from a user operation unit (not shown) And outputs a signal. The high frequency control signal can be controlled in frequency or an on / off duty ratio within a predetermined period can be controlled. Further, the microcomputer unit 50 can implement a container sensing function, which will be described later.

Furthermore, the induction heating cooker according to the present invention further includes an input current measuring unit 62 and an input voltage measuring unit 64 to implement a container sensing function.

The input current measuring unit 62 measures the amount of current input from the commercial power supply 10 to the induction heating cooker. Particularly, the input current measuring section 62 is provided for measuring the input current of the DC power source generating section 20 and the front end of the DC power generating section 20 (in particular, the front end of the rectifying circuit included in the DC power generating section) ), And measures the current flowing between them.

The current can be measured by a method of generating a voltage having a magnitude corresponding to the amount of current flowing in the conductor by the current-voltage conversion circuit CT and calculating the amount of current based on the magnitude of the voltage. This will be described with reference to FIG.

As described above, the input current measuring unit 62 in the present invention measures the amount of current of the alternating current which is not rectified.

Next, the input voltage measuring unit 64 measures the voltage value input from the commercial power supply 10 to the induction heating cooker. In particular, the input voltage measuring unit 64 is provided with a buffer circuit between the DC power generating unit 20 and the switching unit (or the working coil), and the voltage output from the DC power generating unit 20 Voltage) is measured. At this time, the measured DC voltage is equal to the voltage at the DC current applied to the working coil 40.

As described above, the measurement of the voltage can be made with respect to the voltage generated by rectifying in the DC power generation section 20. [ This will be described with reference to FIG.

The microcomputer 50 can calculate the power value by multiplying the current value measured by the input current measuring unit 62 and the voltage value measured by the input voltage measuring unit 64 with each other.

The microcomputer 50 continuously calculates the power value from the time when the induction heating cooker is powered on or when the user's operation occurs and induction heating is started and the power value at each time point (current power value) If it is lower than the reference value, it can be determined that the container is not present in the upper plate.

This can cope with the case where the induction heating is started in a state in which the container is arranged to be shifted to the working coil region of the upper plate, and then, the heating is continued and the container is finally removed.

Here, the reference value may be 1/2 of the maximum value of the current power value. That is, if the current power value is fluctuating between 800 and 900 W, the maximum value of the power value will be 900 W, and the reference value can be 450 W.

Alternatively, the reference value may be preset in advance, for example, for a specific heating intensity set by the user or automatically set by the microcomputer. For example, the reference value may be set to 250 W when heating is performed at an intensity of 600 W, and the reference value may be set to 600 W when heating is performed at an intensity of 1000 W.

In another method of container sensing, if the current power value calculated during induction heating is lower than the power value (initial reference value) calculated and maintained at the time when induction heating starts, the container is placed on the top plate and heated It can be judged that the container is finally removed after starting.

When a container is present in the vicinity of the working coil, the high frequency switched direct current applied to the working coil causes a resonance phenomenon in the working coil (resonance current), which induces an eddy current in the vessel to be induction heated. Therefore, when the energy of the working coil is consumed by the induction heating, the calculated power value will be high, and if the energy of the working coil is not consumed, the calculated power value will be absent or small.

According to such a container sensing function, it is possible to accurately determine whether the container is placed in the area of the working coil correctly, shifted or not by using the input current and the input voltage without disposing a separate container sensing sensor . The detailed operation of the container detection will be described later with reference to Fig.

2 is a circuit diagram for explaining a configuration of an input current measuring unit and an input voltage measuring unit in an induction heating cooker having a container recognition function according to an embodiment of the present invention. 22 VAC commercial AC power is input from the upper left tab (TAP4). The current of the commercial power source is converted into a voltage in the current-voltage conversion circuit CT2, and the converted voltage is rectified and input to the microcomputer through the terminal AC_CT.

At the output terminal Vdc of the central rectifying circuit BD1, a voltage is drawn out, passed through the buffer circuit U8-4, and then input to the microcomputer through the terminal AC_Volt.

In the microcomputer, the current power value is calculated by multiplying the magnitude of the voltage from the terminal AC_CT by the magnitude of the voltage from the terminal AC_Volt.

3 is a flowchart for explaining a container recognition method in an induction heating cooker according to another embodiment of the present invention.

The user can select the heating intensity (S12) when selecting to perform induction heating (S11) after powering on the induction heating cooker. Alternatively, if the user turns on the power of the induction heating cooker, the microcomputer 50 can automatically drive the working coil 40 with a predetermined intensity.

The microcomputer 50 generates a high frequency control signal at a frequency or duty corresponding to the selected heating intensity to control the switching unit 30. [ Thereby, the working coil 40 can induction-heat the container at a set power value (set power value) corresponding to the selected heating intensity (S13).

The microcomputer unit 50 calculates the current power value using the current value from the input current measuring unit 62 and the voltage value from the input voltage measuring unit 64 in real time (S14). Then, the current power value calculated at the time when the induction heating is started is set as the initial reference value and stored (S15). The initial reference value can be designated as a maximum value (maximum power value) at first.

Subsequently, when it is confirmed that the current power value calculated in real time is lowered (S16), it is checked whether or not any condition (no container condition) for judging whether the container 42 is removed from the area of the working coil 40 (S17). If the condition is satisfied, it is determined that the container is not on the upper plate or is shifted too much from the working coil area (S18). If the condition is not satisfied in step S17, the process returns to step S16 to continue the comparison for the current power value.

On the other hand, if it is confirmed in step S16 that the current power value does not drop, it proceeds to step S21 and determines whether it is ascending. If the current power value is higher than the previous power value, the current power value is designated as the maximum power value (S22). Here, if the current power value is higher than the previous current power value but smaller than the previous maximum power value, the maximum power value is maintained as the previous value.

Thereafter, the process returns to step S16 to continuously monitor the current power value.

Here, various conditions can be assumed for the container-free condition.

First, it is possible to set the condition that the current power value measured in real time becomes lower than the initial reference value. This may be the case when the vessel 42 is initially placed in the correct position (either in the working coil area or in the correct position) and then the vessel 42 is removed.

It is also possible to set the condition that the current power value measured in real time becomes smaller than a certain ratio (for example, 1/2) of the maximum power value. Alternatively, it may be a condition that the current power value becomes smaller than a certain ratio of the current set power value or the specific power value.

This can be said to be the case in which the container 42 is placed in a position shifted to the working coil region, is adjusted to a close position, and then removed from the working coil region.

By using such various conditions, it is possible to accurately detect the presence or absence of the container in various cases.

The embodiments of the present invention described above are merely illustrative of the technical idea of the present invention, and the scope of protection of the present invention should be interpreted according to the claims. 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 essential characteristics thereof, It is to be understood that the invention is not limited thereto.

Claims (7)

A DC power generator for receiving and rectifying a commercial power source to generate a DC voltage;
An input current measuring unit for measuring a current value from the commercial power source before being rectified at a previous stage of the rectifying circuit of the DC power generating unit;
An input voltage measuring unit for measuring a voltage value of the DC voltage rectified at a rear end of the rectifying circuit of the DC power generating unit;
A switching unit for turning on / off the application of the DC voltage to the working coil; And
Frequency operation of the switching unit in order to induction-heat the cooking vessel disposed in the vicinity of the working coil, and using the current value measured by the input current measuring unit and the voltage value measured by the input voltage measuring unit The current power value is continuously calculated and a higher value among the current power value calculated after the first input of the commercial power source and the currently held maximum value is renewed as a new maximum value, And determines that the cooking container is not positioned within the allowable range of the working coil when the temperature of the heating coil becomes lower than a predetermined ratio with respect to a maximum value held by the heating coil. delete delete delete A step of switching the DC voltage generated by rectifying the commercial power source by the DC power generator to high frequency and applying the DC voltage to the working coil;
The current power value is continuously calculated using the current value from the commercial power source before being rectified at the previous stage of the rectification circuit of the DC power generation unit and the voltage value of the DC voltage rectified at the rear stage of the rectification circuit of the DC power generation unit step;
The current power value continuously updated after the commercial power is first input and the maximum value currently held are updated as a new maximum value and the calculated current power value is compared with the currently held maximum value And determining that the cooking vessel is not positioned within the allowable range of the working coil when the temperature of the cooking vessel is lowered below a preset ratio. delete delete

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