INDUCTION RANGE AND METHOD OF CONTROLLING THE SAME

Abstract

 The purpose of the present invention is to provide an induction range of which performance degradation can be prevented and which can be used under safe circumstances and a method of controlling the same. The induction range for implementing the same includes an upper plate which supports a to-be-heated object made of a magnetic material, a working coil which is provided under the upper plate and generates an induced current in the to-be-heated object to generate heat, a magnetic material sensing unit which detects whether the magnetic material is present on a bottom surface on which the induction range is placed, and a controller that performs control to inform a user of an unsuitable state of the bottom surface when it is determined that the magnetic material is present on the bottom surface based on a signal received from the magnetic material sensing unit.

Description

BACKGROUND

1. Field of the Invention

[0001] The present invention relates to an induction range capable of detecting a magnetic material on a bottom surface and a method of controlling the same.

2. Discussion of Related Art

[0002] In general, an induction range pertains to an electromagnetic induction heating cooking device and has a structure in which, when a magnetic metal is placed in a magnetic field, the metal itself generates heat by itself through a current generated by electromagnetic induction in order to cook food.

[0003] The induction range is being developed into a lighter and slimmer form to increase portability so that a user may use the induction range in various environments, and thus, a distance between a working coil and a bottom surface is inevitably close.

[0004] In this way, when a slim induction range is used and a magnetic material is placed on the bottom surface, it is difficult for the user to visually identify whether the magnetic material is present on the bottom surface. Thus, when the induction range operates in a state in which the magnetic material is present, the magnetic material on the bottom surface is may be induction-heated to increase a temperature of the bottom surface, the temperature of the bottom surface increases due to radiant heat of a cooking container, and thus, this may cause problems in terms of safety of the user and product performance.

[0005] As a way to prevent these problems, a manner may be considered in which the distance between the working coil and the bottom surface may sufficiently increase, an aluminum plate may be provided between the working coil and the bottom surface on which the induction range is placed (i.e., a bottom side of the induction range), and thus the temperature of the bottom surface may be prevented from increasing.

[0006] However, it is difficult to implement a slim product when the distance between the working coil and the bottom surface increases significantly. Further, even when the aluminum plate is provided on the bottom side of the induction range, when a magnetic material is present on the bottom surface, a thickness of the aluminum plate should increase to prevent an increase in the temperature of the bottom surface, and thus product price increases.

[0007] Korean Laid-open Patent Publication No. 10-2024-0082045 is disclosed as the related art of the induction range.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to providing an induction range of which performance degradation is prevented and which may be used under safe circumstances, and a method of controlling the same.

[0009] According to an aspect of the present invention, there is provided an induction range including an upper plate which supports a to-be-heated body, a working coil which is provided under the upper plate and generates an induced current in the to-be-heated body to generate heat, a magnetic material sensing unit which detects whether the magnetic material is present on a bottom surface, and a controller that performs control to inform a user of an unsuitable state of the bottom surface when it is detected in the magnetic material sensing unit that the magnetic material is present.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects, features, and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view illustrating an induction range according to an embodiment of the present invention;

FIG. 2 is a circuit diagram illustrating a magnetic material sensing unit according to the embodiment of the present invention; and

FIGS. 3 to 5 are flowcharts illustrating a method of controlling the induction range according to the embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0011] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0012] An induction range 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[0013] The induction range 1 includes an upper plate 10 that supports a to-be-heated object, a working coil base 20 provided under the upper plate 10, a working coil 30 that is wound on an upper surface of the working coil base 20 and generates an induction current on the to-be-heated object to generate heat, a center sensor 40 that measures a temperature of the to-be-heated object while in direct or indirect contact with a bottom surface of the upper plate 10, an internal temperature sensor 50 that measures a temperature inside the induction range 1 to identify whether the induction range 1 malfunctions, a bottom temperature sensor 60 that measures a temperature of a bottom surface 2, and a substrate 70 on which a plurality of components for controlling the induction range 1 are mounted in order to constitute a controller.

[0014] The upper plate 10 may be formed to have a quadrangular plate shape and may be formed of a ceramic or glass material having excellent heat resistance. The upper plate 10 is provided to cover an upper portion of the induction range 1 to support the to-be-heated object such as a container. At least one burner for heating the to-be-heated object in a state in which the to-be-heated object is placed is formed in the upper plate 10. The upper plate 10 is provided with an operation unit (not illustrated) so that the user may perform operation. The operation unit may include a power button for applying power, a burner heating button for heating a burner to be used, an output power adjusting button for adjusting output power, and the like. The operation unit may be displayed on the upper plate 10 of the induction range 1 in the form of a display.

[0015] A concave working coil seating groove 20a is formed on an upper surface of the working coil base 20. The working coil 30 is spirally wound a plurality of times along the working coil seating groove 20a.

[0016] The working coil 30 is made of a conductive material, receives power by control of the controller, and induces and heats the to-be-heated object seated on the upper surface of the upper plate 10. When power is supplied to the working coil 30, the to-be-heated object is induced and heated.

[0017] It is preferable that the to-be-heated object be made of a magnetic material such as stainless steel to generate an eddy current caused by induced electricity according to magnetism formed in the working coil 30.

[0018] The internal temperature sensor 50 measures the temperature inside the induction range 1 to identify whether the induction range 1 malfunctions due to a defect of a fan (not illustrated) provided inside the induction range 1 or a blocked fan exhaust.

[0019] The bottom temperature sensor 60 detects whether heat is generated near the bottom surface 2. As the induction range 1 is used in a state in which the magnetic material is present on the bottom surface 2, when the magnetic material is heated or heat is generated near the bottom surface 2 due to the defect of the fan (not illustrated) provided inside the induction range 1 or the blocked fan exhaust, a safety problem may occur or performance may be degraded.

[0020] When the bottom temperature sensor 60 detects a temperature of the bottom surface and the detected temperature is higher than a set temperature, the controller may control the output power to ensure user safety and prevent performance degradation. The bottom temperature sensor 60 may be provided on a bottom surface of the substrate 70.

[0021] The substrate 70 is provided on a bottom side of the induction range 1 which is spaced apart downward from the bottom surface of the working coil base 20. The substrate 70 is provided with a magnetic material sensing unit 80 for generating a signal when the magnetic material is detected.

[0022] The magnetic material sensing unit 80 determines whether the magnetic material is present by generating a magnetic material sensing signal (first sensing signal) when the magnetic container is placed on the burner of the upper plate 10 or generating a magnetic material sensing signal (second sensing signal) when the magnetic material is present near the bottom surface 2. The first sensing signal and the second sensing signal may be composed of two sensing signals generated from one magnetic material sensing unit 80 or, may be composed of two sensing signals generated from two magnetic meterial sensing units, respectively.

[0023] The magnetic material sensing unit 80 generates a magnetic material sensing signal and propagates the generated magnetic material sensing signal to the surroundings. The magnetic material sensing signal is a free resonance waveform that is generated by a resonance frequency of an L-C load circuit, and a resonance frequency of the magnetic material sensing signal is changed by the magnetic material that is a metal derivative present therearound at the same time that the magnetic material sensing signal is generated.

[0024] For example, a circuit as illustrated in FIG. 2 may be used as the magnetic material sensing unit 80. The magnetic material sensing unit 80 includes a sensing signal generating unit 81, a comparator S2, and a determination unit 82.

[0025] The sensing signal generating unit 81 includes a coil L1 and a capacitor C1 connected in parallel between a first power source V1 and a first node n1 and includes a transistor S1 provided between the first node n1 and a ground terminal and driven by a one-pulse signal. The sensing signal generating unit 81 generates a sensing signal by being operated while the one-pulse signal is applied.

[0026] Here, the one-pulse signal is a single pulse signal and turns the transistor S1 on during one pulse duty. The transistor S1 operates for one pulse duty to generate an LC free resonance signal by the coil L1 and the capacitor C1. In this case, a resonance frequency of the resonance signal is changed by inductance induced by the magnetic material on the bottom surface 2 or the magnetic material on the burner. Thus, when the magnetic material is present, the resonance frequency of the resonance signal output from the sensing signal generating unit 81 decreases and the number of vibrations decreases.

[0027] The comparator S2 compares the resonance signal output from the sensing signal generating unit 81 with a reference signal V2 to generate a square wave.

[0028] The determination unit 82 determines whether the magnetic material is present by counting the number of square waves output from the comparator S2. The determination unit 82 may be included in the controller.

[0029] The number of square waves changes depending on whether a to-be-detected object constitutes the magnetic material or a non-magnetic material, and in the case that there is the magnetic material, the number of square waves changes depending on whether a position of the magnetic material is close to or far from the working coil 30.

[0030] The number of counted waveforms (first waveform number) when the to-be-detected object present on the bottom surface 2 is a non-magnetic material is greater than the number of counted waveforms (second waveform number) when the to-be-detected object present on the bottom surface 2 is the magnetic material. For example, the number of waveforms of wood bases in which the to-be-detected object present on the bottom surface 2 constitutes a non-magnetic material is 27, and the number of waveforms of aluminum is 28. On the other hand, the number of waveforms of STS 304, which is the magnetic material, is 18, and the number of waveforms of iron is 14.

[0031] Meanwhile, when the to-be-detected object is close to the working coil 30 in the burner of the upper plate 10, induction heating is performed well, and thus the number of waveforms counted decreases, and when the to-be-detected object is far from the working coil 30 in the bottom surface 2, induction heating is not performed well, and thus the number of waveforms counted increases. When the to-be-detected object present on the burner of the upper plate 10 is a non-magnetic material, a third waveform number that is smaller than the second waveform number is counted, and when the to-be-detected object present on the burner of the upper plate 10 constitutes the magnetic material, a fourth waveform number that is smaller than the third waveform number is counted. For example, the numbers of third waveforms and the fourth waveforms are generally no more than 5.

[0032] The controller performs setting so that a predetermined waveform number between the first waveform number and the second waveform number is defined as a first reference waveform number, a predetermined waveform number between the second waveform number and the third waveform number is defined as a second reference waveform number, and a predetermined waveform number between the third waveform number and the fourth waveform number is defined as a third reference waveform number. The controller determines that the to-be-detected object of the bottom surface 2 is a non-magnetic material when the number of waveforms measured is greater than the first reference waveform number, determines that the magnetic material is present on the bottom surface 2 when the number of waveforms measured is between the first reference waveform number and the second reference waveform number, determines that the non-magnetic material is placed on the burner when the number of waveforms measured is between the second reference waveform number and the third reference waveform number, and determines that the magnetic material is placed on the burner when the number of waveforms measured is smaller than the third reference waveform number.

[0033] Thus, it is possible to determine whether the magnetic container is placed on the burner and whether the magnetic material is present on the bottom surface 2 based on the number of waveforms counted through the magnetic material sensing unit 80.

[0034] According to the above configuration, it is possible to identify in advance whether the magnetic material is present on the bottom surface 2 through the magnetic material sensing unit 80 to prevent performance degradation caused by using the induction range 1 in the presence of the magnetic material and to allow the user to use the induction range 1 safely.

[0035] Further, the presence or absence of the magnetic material can be determined by the number of waveforms generated by the magnetic material sensing unit 80 composed of a circuit, thereby preventing an increase in the temperature of the bottom surface 2 with a simple configuration and implementing the induction range 1 in a slim form.

[0036] A control method performed by the controller of the induction range 1 according to the embodiment of the present invention will be described with reference to FIGS. 3 to 5.

[0037] Operation S11 is an operation of applying power to the induction range 1. Power is applied by the user plugging a power cord of the induction range 1 into an outlet, and the control process proceeds to operation S12.

[0038] In operation S12, it is determined whether the container is placed on the burner of the induction range 1. In this case, whether the magnetic container is placed on the burner is determined based on the number of waveforms counted by the magnetic material sensing unit 80, and when the number of waveforms measured is smaller than the third reference waveform number, it is determined that the magnetic container is placed on the burner. As a result of the determination, when the magnetic container is placed on the burner, the control process proceeds to operation S13. Otherwise, the control process proceeds to operation S14.

[0039] In operation S13, it is determined whether the power button is pressed by the user. Power may be supplied to an internal component of the induction range 1 by the user touching the power button. As a result of the determination, when the power button is pressed, the control process proceeds to operation S22. Otherwise, the control process proceeds to operation S19.

[0040] In operation S19, there is a wait for a set time. The set time may be set to, for example, 1 minute. When there is no set time or the set time is too short, power consumption may increase due to repeated processes of operation S12 and operation S13, and when the set time is too long, a change in situation in operation S12 and operation S13 cannot be detected early during the wait time. Therefore, it is preferable that the set time be set to a proper time in consideration of these features. After the wait for the set time, the control process proceeds to operation S12.

[0041] In operation S14, it is determined whether the magnetic material is present on the bottom surface 2. When the magnetic container is placed on the burner and the magnetic material is also present on the bottom surface 2, it becomes difficult to determine whether the magnetic material is present on the bottom surface 2 based on the number of waveforms measured. Thus, the determination on whether the magnetic material is present on the bottom surface 2 is performed only when the container is not placed on the burner in operation S12. In this case, whether the magnetic material is present on the bottom surface 2 may be determined based on the number of waveforms counted by the magnetic material sensing unit 80, and when the number of waveforms measured is between the first reference waveform number and the second reference waveform number, it is determined that the magnetic material is present on the bottom surface 2. As a result of the determination, when the magnetic material is present on the bottom surface 2, the control process proceeds to operation S16. Otherwise, the control process proceeds to operation S15.

[0042] In operation S15, it is determined whether the power button is pressed by the user. Since it is determined that the magnetic material is not present on the bottom surface 2, the induction range 1 may be used, and thus operation S15 is an operation of waiting for the power button to be pressed by the user. As a result of the determination, when the power button is pressed, the control process proceeds to operation S17. Otherwise, the control process proceeds to operation S19.

[0043] In operation S17, the user is informed of the suitability of the bottom surface. That is, since the magnetic material is not present on the bottom surface 2, it is suitable for use of the induction range 1, and thus operation S17 is an operation of notifying the user of suitability through at least one of a voice and a display. After informing of the bottom surface suitability, the control process proceeds to operation S22.

[0044] Meanwhile, when it is determined in operation S14 that the magnetic material is present on the bottom surface 2, the control process proceeds to operation S16, and it is determined in operation S16 whether the power button is pressed by the user. As a result of the determination, when the power button is pressed, the control process proceeds to operation S20. Otherwise, the control process proceeds to operation S19 and proceeds to operation S12 after waiting for the set time.

[0045] In operation S20, the user is informed of the unsuitability of the bottom surface. That is, since the magnetic material is present on the bottom surface 2 and it is not suitable for the use of the induction range 1, operation S20 is an operation of recommending resolving an unsuitable state of the bottom surface 2 by guiding the user to move a position of the burner to be used or remove the magnetic material through at least one of a voice and a display. After guidance on the unsuitable state of the bottom surface, assuming that the unsuitable state of the bottom surface 2 is resolved, the control process proceeds to operation S22, and an operation of heating the burner is performed.

[0046] It is determined in operation S22 whether the burner heating button is pressed by the user. As a result of the determination, when the burner heating button is pressed, the control process proceeds to operation S24. Otherwise, operation S22 is repeatedly performed until the burner heating button is pressed.

[0047] It is determined in operation S24 once again whether the magnetic container is placed on the burner. As a result of the determination, when the magnetic container is placed, the control process proceeds to operation S26. Otherwise, the control process proceeds to operation S25.

[0048] In operation S25, the user is informed that there is no magnetic container, and after the heating of the burner is canceled, a control process is terminated.

[0049] In operation S26, the heating of the burner starts.

[0050] After the heating of the burner starts, the control process proceeds to operation S28 to measure a bottom surface temperature ST, and in operation S30, user setting output power SP, which is output power set through the output power adjusting button by the user, is stored in the controller. The bottom surface temperature ST is a temperature measured by the bottom temperature sensor 60.

[0051] After the user setting output power is stored, through operations S32 to S64, control is performed to adjust the output power so that the bottom surface temperature ST does not overheat beyond a set temperature. When the burner is heated in a state in which the magnetic material is present on the bottom surface 2, the bottom surface temperature ST increases abnormally, and thus safe use is achieved through a process of controlling the output power so that the bottom surface temperature ST is not higher than the set temperature.

[0052] In operation S32, the bottom surface temperature ST and a first set temperature T1 are compared to each other to determine whether the bottom surface temperature ST is lower than the first set temperature T1. The first set temperature T1 may be set to, for example, 70 °C. The first set temperature T1 refers to a temperature recognized as the bottom surface temperature ST that may increase when the burner is heated in a normal situation in which the magnetic material is not present on the bottom surface 2. Thus, when the bottom surface temperature ST is lower than the first set temperature T1, it is determined that the bottom surface temperature ST1 is a normal temperature, and the control process proceeds to operation S34. Otherwise, the control process proceeds to operation S38.

[0053] In operation S34, the heating is performed at the user setting output power SP set by the user. Since the bottom surface temperature ST is a normal temperature, the heating is performed at the user setting output power SP without changing the output power set by the user, and the control process proceeds to operation S36.

[0054] In operation S36, it is determined whether a button for canceling the heating of the burner is pressed. When a signal is input which is obtained by the user pressing a button for canceling the heating of the burner to terminate the use of the induction range 1, the control process is terminated, or otherwise, the control process proceeds to operation S32, and the process is repeated.

[0055] In operation S38, it is determined whether the bottom surface temperature ST is higher than or equal to the first set temperature T1 and lower than a second set temperature T2. The second set temperature T2 may be higher than the first set temperature T1, and may be set to, for example, 80 °C. The second set temperature T2 and a third set temperature T3 which will be described below are set to control the output power when the temperature of the bottom surface 2 increases due to an abnormal situation such as a case in which the magnetic material is present on the bottom surface 2.

[0056] The fact that the control process proceeds to operation S32 through operation S38 is to prevent an increase in the bottom surface temperature ST by controlling the output power so that the bottom surface temperature ST is higher than the first set temperature T1 that is a normal temperature as a result of heating at the user setting output power SP set by the user. As a result of the determination, when the bottom surface temperature ST is higher than or equal to the first set temperature T1 and lower than the second set temperature T2, the control process proceeds to operation S40. Otherwise, the control process proceeds to operation S46.

[0057] In operation S40, it is determined whether the user setting output power SP set by the user is greater than first setting output power P1. The first setting output power P1 may be preset in the controller and may be set to, for example, 1500 W. As a result of the determination, when the user setting output power SP is greater than the first setting output power P1, the control process proceeds to operation S42, and the heating is performed at the first setting output power P1 which is a lower output power among the two output powers. Otherwise, the control process proceeds to operation S41, and the heating is performed at the user setting output power SP which is a lower output power among the two types of output power. In this way, the user setting output power SP is used as an upper limit, but the heating is performed at a lower output power among the user setting output power SP and the first setting output power P1, and thus the bottom surface temperature ST may be prevented from increasing. After the heating at the output powers of operations S41 and S42, the control process proceeds to operation S44.

[0058] In operation S44, it is determined again whether the bottom surface temperature ST is higher than or equal to the first set temperature T1 and lower than the second set temperature T2. As a result of the determination, when the bottom surface temperature ST is maintained at a temperature higher than or equal to the first set temperature T1 and lower than the second set temperature T2, the control process proceeds to operation S40. Otherwise, the control process proceeds to operation S32 to determine whether the bottom surface temperature ST is lower than the first set temperature T1 or higher than or equal to the second set temperature T2. After the control process proceeds to operation S32, when the bottom surface temperature ST is lower than the first set temperature T1, the output power may increase to the user setting output power SP set by the user, and then the heating is performed.

[0059] Operations S46 to S52 and S54 to S64 include the control processes in common to the control processes performed in operations S38 to S44, but the bottom surface temperature ST is higher, and thus the compared set temperature is different.

[0060] In operation S46, it is determined whether the bottom surface temperature ST is higher than or equal to the second set temperature T2 and lower than the third set temperature T3. The third set temperature T3 may be higher than the second set temperature T2, and may be set to, for example, 90 °C. A state in which the control process proceeds to operations S46 to S52 is to prevent the bottom surface temperature ST from further increasing, by controlling the output power so that the bottom surface temperature ST is higher than the second set temperature T2 as a result of the heating at the user setting output power PS set by the user or the first setting output power P1. As a result of the determination, when the bottom surface temperature ST is higher than or equal to the second set temperature T2 and lower than the third set temperature T3, the control process proceeds to operation S48. Otherwise, the control process proceeds to operation S54.

[0061] In operation S48, it is determined whether the user setting output power SP is greater than second setting output power P2. The second setting output power P2 may be preset in the controller, set to be lower than the first setting output power P1, and set to, for example, 1300W. As a result of the determination, when the user setting output power SP is greater than the second setting output power P2, the control process proceeds to operation S50, and the heating is performed at the second setting output power P2 which is a lower output power among the two types of output power. Otherwise, the control process proceeds to operation S49, and the heating is performed at the user setting output power SP which is a lower output power among the two types of output power. In this way, the user setting output power SP is used as the upper limit, but the heating is performed at a lower output power of the user setting output power SP and the second setting output power P2, and thus the bottom surface temperature ST may be prevented from increasing. After the heating at the output power of operations S49 and S50, the control process proceeds to operation S52.

[0062] In operation S52, it is determined again whether the bottom surface temperature ST is higher than or equal to the second set temperature T2 and lower than the third set temperature T3. As a result of the determination, when the bottom surface temperature ST is maintained at a temperature higher than or equal to the second set temperature T2 and lower than the third set temperature T3, the control process proceeds to operation S48. Otherwise, the process proceeds to operation S32 once again.

[0063] In operation S54, it is determined whether the bottom surface temperature ST is higher than or equal to the third set temperature T3. As a result of the determination, when the bottom surface temperature ST is higher than or equal to the third set temperature T3, the control process proceeds to operation S56. Otherwise, the control process proceeds to operation S32.

[0064] In operation S56, it is determined whether the user setting output power SP is greater than a third setting output power P3. The third setting output power P3 may be preset in the controller, set to be lower than the second setting output power P2, and set to, for example, 1100W. As a result of the determination, when the user setting output power SP is greater than the third setting output power P3, the control process proceeds to operation S58, and the heating is performed at the third setting output power P3 which is a lower output power among the two types of output power. Otherwise, the control process proceeds to operation S57, and the heating is performed at the user setting output power SP which is a lower output power among the two output powers. In this way, the user setting output power SP is used as the upper limit, but the heating is performed at a lower output power among the user setting output power SP and the third setting output power P3, and thus the bottom surface temperature ST may be prevented from increasing. After the heating at the output powers of operations S57 and S58, the control process proceeds to operation S60.

[0065] In operation S60, it is determined again whether the bottom surface temperature ST is higher than or equal to the third set temperature T3. As a result of the determination, when the bottom surface temperature ST is higher than or equal to the third set temperature T3, the control process proceeds to operation S62. Otherwise, the control process proceeds to operation S32 once again.

[0066] In operation S62, it is determined whether the bottom surface temperature ST is higher than or equal to the third set temperature T3 for a set period of time. As a result of the determination, when the bottom surface temperature ST is higher than or equal to the third set temperature T3 for the set period of time, the control process proceeds to operation S64. Otherwise, the control process proceeds to operation S56.

[0067] In operation S64, high-temperature warning is provided, and heating of the burner is canceled. When the bottom surface temperature ST is higher than or equal to the third set temperature T3 for a long time, safety problems occur. Thus, for safety, the user is informed through at least one of a voice and a display that the bottom surface 2 is hot, and thus the heating is canceled for safety and product performance, the heating is canceled, and then the control process is terminated.

[0068] When the output power is initially controlled after the temperature of the bottom surface 2 reaches the third set temperature T3, the temperature of the bottom surface 2 may be much higher than the third set temperature T3 due to radiant heat of the container being heated and residual heat of the bottom surface 2. Thus, as described above, as the temperature of the bottom surface 2 increases, the set temperature is classified into a plurality of set temperatures such as the first set temperature, the second set temperature, and the third set temperature. When the output power is sequentially controlled in respective temperature stages, the temperature of the bottom surface 2 can be prevented from increasing to the third set temperature T3 or higher, which is the highest temperature of the set temperatures. Thus, safety can be improved, an output power limit can be minimized, and thus the output power set by the user can be produced as much as possible.

[0069] Through the control processes, the user can be informed whether the magnetic material is present on the bottom surface 2, and thus the user can use the induction range 1 safely. Further, by controlling the output power based on the temperature of the bottom surface 2, the temperature of the bottom surface 2 can be prevented from increasing due to an abnormal situation including a situation in which the magnetic material is present on the bottom surface 2.

[0070] According to the present invention, performance degradation caused by a magnetic material on a bottom surface can be prevented, and a user can use an induction range under safe circumstances.

[0071] Further, an increase in temperature of the bottom surface can be prevented using a simple configuration, and thus a slim product can be implemented.

[0072] As described above, exemplary embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various modifications may be implemented without departing from the appended claims, the detailed description of the invention, and the accompanying drawings and are also belong to the present invention.

Claims

1. An induction range comprising:

an upper plate which supports a to-be-heated object made of a magnetic material;

a working coil which is provided under the upper plate and generates an induced current in the to-be-heated object to generate heat;

a magnetic material sensing unit which detects whether the magnetic material is present on a bottom surface on which the induction range is placed; and

a controller that performs control to inform a user of an unsuitable state of the bottom surface when it is determined that the magnetic material is present on the bottom surface based on a signal received from the magnetic material sensing unit.

2. The induction range of claim 1, wherein the magnetic material sensing unit includes a sensing signal generating unit that generates a pulse signal, a comparator that generates a waveform after comparing the signal output by the sensing signal generating unit with a reference signal, and a determination unit that determines whether the magnetic material is present by counting the number of waveforms output by the comparator.

3. The induction range of claim 2, wherein the controller determines whether the to-be-heated object made of the magnetic material is present on the upper plate, and
a distance from the working coil to the to-be-heated object present on the upper plate is smaller than a distance from the working coil to the magnetic material present on the bottom surface.

4. The induction range of claim 3, wherein the controller determines whether a to-be-detected object present on the upper plate is a magnetic material or a non-magnetic material and whether the to-be-detected object present on the bottom surface is a magnetic material or a non-magnetic material based on the number of waveforms.

5. The induction range of claim 4, wherein the controller sets a first reference waveform number, a second reference waveform number having the number of waveforms smaller than that of the first reference waveform number, and a third reference waveform number smaller than the second reference waveform number, and
the controller determines that a non-magnetic material is present on the bottom surface when the number of waveforms counted by the magnetic material sensing unit is greater than the first reference waveform number, determines that a magnetic material is present on the bottom surface when the number of waveforms counted by the magnetic material sensing unit is between the first reference waveform number and the second reference waveform number, determines that the non-magnetic material is present on the upper plate when the number of waveforms counted by the magnetic material sensing unit is between the second reference waveform number and the third reference waveform number, and determines that the magnetic material is present on the upper plate when the number of waveforms counted by the magnetic material sensing unit is smaller than the third reference waveform number.

6. The induction range of claim 1, further comprising a bottom temperature sensor that measures a temperature of the bottom surface,
wherein the controller adjusts output power after comparing the temperature of the bottom surface measured by the bottom temperature sensor and a set temperature.

7. A method of controlling an induction range including an upper plate which supports a to-be-heated object, a working coil which is provided under the upper plate and generates an induced current in the to-be-heated object to generate heat, and a controller which controls supply of power to the working coil, the method comprising:

an operation a) of determining, by the controller, whether a magnetic material is present on a bottom surface of the induction range, from a signal received from a magnetic material sensing unit;

an operation b) of informing, by the controller, a user of an unsuitable state of the bottom surface when it is determined that the magnetic material is present on the bottom surface; and

an operation c) of heating a burner after determining whether the to-be-heated object is placed on the burner when a burner heating button is pressed by the user.

8. The method of claim 7, wherein the controller determines whether the to-be-heated object is present on the burner of the upper plate and then performs control to perform the operation a) when the to-be-heated object is not present on the burner.

9. The method of claim 7, wherein a temperature of the bottom surface is measured by a bottom temperature sensor, and
the controller performs control such that output power is adjusted after comparing the temperature of the bottom surface measured by the bottom temperature sensor with a set temperature.

10. The method of claim 9, wherein the set temperature is provided as a plurality of set temperatures including a first set temperature that is a lowest temperature,

when the temperature of the bottom surface is lower than the first set temperature, heating is performed at a user setting output power set by the user, and

when the temperature of the bottom surface is higher than the first set temperature, the user setting output power set by the user is used as an upper limit, and heating is performed at a lower output power among the user setting output power and set output power present in the controller.

Drawing