JP6195174B2 - Induction heating device - Google Patents

Description

  The present disclosure relates to an induction heating apparatus. In particular, the present invention relates to an induction heating apparatus that induction-heats an object to be heated such as a metal cooking pan placed on a top plate.

  In an induction heating cooker generally used as an induction heating device, for example, one or two heating coils are disposed immediately below the top plate, and are placed on the top plate by the heating coil. A metal cooking pan that is an object to be heated is heated by induction.

  Moreover, in the induction heating cooker, the multi-coil structure which has arrange | positioned many heating coils just under the top plate is proposed (for example, refer patent document 1).

  In the cooking device of Patent Document 1, a number of heating coils laid under the top plate are arranged close to each other, and an object to be heated such as a cooking pan is placed at any position on the top plate. However, it has a configuration capable of induction heating.

  Furthermore, the multi-coil structure which heats the cooking pan which is a to-be-heated object with many heating coils is described in patent document 2, for example. The heating cooker described in Patent Document 2 supplies a radio frequency AC signal to each heating cell and detects an induction signal in a conductive loop located between the object to be heated and the heating cell. Have. Since this induction signal changes depending on the existence of the object to be heated, the position of the object to be heated placed on the top plate can be detected.

German Patent Application No. 102010028549 EP 1206164

  As described above, the heating cooker described in Patent Document 2 has a conductive loop for detecting the position of an object to be heated and / or an AC signal source in a radio frequency band. There is a problem that the number of components increases and the cost increases.

  When there are many component parts of a cooking-by-heating machine, the time required to assemble a product will become long and it had the subject that manufacturing cost became high.

  In particular, in the induction heating apparatus having a multi-coil configuration, a configuration of conductive loops corresponding to the number of heating coils is required, so that an increase in cost is greatly increased.

  Further, as a method generally used as a means for detecting an object to be heated on the top plate, there is a method for detecting a current flowing through a heating coil and / or a generated voltage. In this method, an inverter for supplying power to the heating coil is operated to detect a current flowing from the power source to the inverter and a current flowing to the heating coil and / or a generated voltage. The object to be heated is detected from the correlation.

  However, in this system, it is general that the control unit drives the inverter after receiving an operation command signal instructing the start of the heating operation, and shifts to the heating operation when an object to be heated is detected. Therefore, in the conventional induction heating cooker, the object to be heated cannot be detected by the inverter before the control unit receives the operation command signal instructing the start of the heating operation.

  In addition, when detecting an object to be heated by the operation of the inverter, an inverter that supplies power of about several hundred watts during rated heating is used. Therefore, the conventional induction heating cooker greatly reduces the power consumption to several W level even if the inverter is operated so that the power supplied from the inverter to the heated object is minimized when the heated object is detected. Is difficult.

  Therefore, if a conventional induction heating cooker detects an object to be heated with many heating coils at the same time, the power required for detecting the object to be heated increases, and in some cases, only the detection operation of the object to be heated is detected. In this case, the rated power is exceeded and there is a problem that it is difficult to detect a heated object such as a pan.

  In addition, when heating an object to be heated in some areas, the power that can be used to detect the object to be heated is smaller than the rated power of the device, making it even more difficult to detect the object to be heated. Become.

  In addition, when the object to be heated is simultaneously detected by a large number of heating coils, the leakage magnetic field generated from the induction heating device becomes large because the magnetic fields generated from the individual heating coils are propagated in an integrated state. And it had the subject that this leakage magnetic field may have bad influences, such as malfunction of a peripheral device.

  Furthermore, in the induction heating apparatus having a multi-coil configuration, a large number of heating coils are arranged adjacent to each other. Therefore, the conventional induction heating cooker has a problem that the magnetic field generated from each adjacent heating coil interferes with each other and the detection value from the heating coil increases or decreases, and the object to be heated on the top plate cannot be detected with high accuracy. Had.

  The present disclosure can accurately detect whether an object to be heated is placed on the top plate in a multi-coil configuration in which a large number of heating coils are disposed under the top plate, and reduce the manufacturing cost. It aims at providing the induction heating apparatus which can be made low.

In order to solve the conventional problem, an induction heating apparatus according to one aspect of the present disclosure is provided.
A top plate for placing an object to be heated;
A plurality of heating coils disposed below the top plate;
An inverter for supplying a high-frequency current to the plurality of heating coils;
A control unit for controlling the output of the inverter;
An operation display unit that outputs an operation command to the control unit;
A heated object detection unit for detecting the presence or absence of the heated object placed on the top plate;
With
The control unit supplies a detection current for detecting the presence or absence of the object to be heated to the plurality of heating coils before receiving an operation command signal instructing the start of a heating operation from the operation display unit. Controlling the inverter to
The object to be heated is detected from an input current and / or output voltage in a power transmission path from a power source to the heating coil during a detection period in which the detection current is supplied to the heating coil. The presence or absence of is detected.

  The induction heating apparatus according to the present disclosure is used only for detection of an object to be heated by causing an electric current to be detected to detect the presence or absence of the object to be heated to the heating coil by the operation of the inverter before starting the heating of the object to be heated. It is possible to detect an object to be heated without adding new components.

It is a schematic plan view of the induction heating device of the first embodiment according to the present disclosure. It is a longitudinal cross-sectional view of the induction heating apparatus cut | disconnected by the AA line in FIG. It is a block diagram which shows the structure of the induction heating apparatus of Embodiment 1 which concerns on this indication. It is a figure which shows the circuit structure of the induction heating apparatus of Embodiment 1 which concerns on this indication. It is explanatory drawing which shows the relationship between the electric current from the power supply of the induction heating apparatus of Embodiment 1 which concerns on this indication, and the voltage which generate | occur | produces in an inverter. It is a time chart of the detection operation of the to-be-heated object of the induction heating apparatus of Embodiment 1 which concerns on this indication. It is a time chart of the detection operation of the to-be-heated object of the induction heating apparatus of Embodiment 1 which concerns on this indication. It is a time chart of the detection operation | movement of the to-be-heated object of the induction heating apparatus of Embodiment 2 which concerns on this indication. It is a time chart of the detection operation | movement of the to-be-heated object of the induction heating apparatus of Embodiment 3 which concerns on this indication, and heating operation. It is a time chart of the detection operation | movement of the to-be-heated object of the induction heating apparatus of Embodiment 4 which concerns on this indication, and heating operation. It is a schematic plan view of the induction heating apparatus of Embodiment 5 which concerns on this indication. It is a time chart of the detection operation of the to-be-heated object of the induction heating apparatus of Embodiment 5 which concerns on this indication. It is a time chart of the detection operation of the to-be-heated object of the induction heating apparatus of Embodiment 6 which concerns on this indication. It is a time chart of the detection operation | movement of the to-be-heated object of the induction heating apparatus of Embodiment 7 which concerns on this indication. It is explanatory drawing which shows the relationship between the input current from the power supply of the induction heating apparatus of Embodiment 8 which concerns on this indication, and the output voltage which generate | occur | produces in an inverter. It is explanatory drawing which shows the relationship between the input current from the power supply of the induction heating apparatus of Embodiment 9 which concerns on this indication, and the output voltage which generate | occur | produces in an inverter. It is explanatory drawing which shows the direction of the electric current of the heating coil in the induction heating apparatus of Embodiment 10 which concerns on this indication.

The induction heating device of the first aspect according to the present disclosure is:
A top plate for placing an object to be heated;
A plurality of heating coils disposed below the top plate;
An inverter for supplying a high-frequency current to the plurality of heating coils;
A control unit for controlling the output of the inverter;
An operation display unit that outputs an operation command to the control unit;
A heated object detection unit for detecting the presence or absence of the heated object placed on the top plate;
With
The control unit supplies a detection current for detecting the presence or absence of the object to be heated to the plurality of heating coils before receiving an operation command signal instructing the start of a heating operation from the operation display unit. Controlling the inverter to
The object to be heated is detected from an input current and / or output voltage in a power transmission path from a power source to the heating coil during a detection period in which the detection current is supplied to the heating coil. The presence or absence of is detected.

  Thus, the object to be heated can be detected without adding a new component only for detecting the object to be heated.

  In the induction heating apparatus according to the second aspect of the present disclosure, the control unit according to the first aspect sequentially supplies the detection current to the plurality of heating coils, and the detection current is supplied. The inverter control is performed so that the detection current is not supplied to the heating coil adjacent to the heating coil at the same time.

  In addition, the control unit is configured so that the current value of the detection current supplied to the heating coil is smaller than the current value of the heating current supplied to the heating coil to heat the object to be heated. Is supposed to be controlled.

  In the induction heating apparatus according to the third aspect of the present disclosure, the current value of the detected current supplied to the heating coil in the first or second aspect is the heating coil for heating the object to be heated. Smaller than the current value of the heating current supplied to.

  In addition, when the control unit supplies the detection current to the plurality of heating coils before receiving an operation command signal instructing the start of the heating operation from the operation display unit, the control unit supplies the plurality of heating coils with the detection current. The inverter is controlled so as to switch between when the detection current is supplied and when the detection current is not supplied within a certain period and to perform a periodic operation.

  In the induction heating apparatus according to the fourth aspect of the present disclosure, the control unit according to any one of the first to third aspects supplies the detected current to a heating coil adjacent to the heating coil performing the heating operation. The inverter is controlled not to be supplied.

  Further, the control unit supplies the detection current when supplying the detection current to the plurality of heating coils before receiving a signal of an operation command instructing start of a heating operation from the operation display unit. The inverter is controlled such that the timing of supplying the detection current is shifted between the plurality of heating coils by sequentially changing the heating coils.

  In the induction heating apparatus according to the fifth aspect of the present disclosure, the control unit according to any one of the first to fourth aspects is configured such that the object to be heated is detected even after the object detection unit detects the object to be heated. The inverter is controlled so as to supply the detection current to the heating coil in which is detected, and the detection operation of the heated object by the heated object detection unit is continued.

In the induction heating apparatus according to the sixth aspect of the present disclosure, the plurality of heating coils according to any one of the first to fifth aspects includes a heating coil group including at least two heating coils.
The control unit controls the inverter so as to supply the detection current to all the heating coils in the heating coil group simultaneously.

  In the induction heating apparatus according to a seventh aspect of the present disclosure, the control unit according to any one of the first to sixth aspects is configured such that after the object to be heated is detected by the object to be heated detection unit, the object to be heated is detected. The inverter is controlled so that the detected current is continuously supplied to the heating coil in which the heated object is detected until no heated object is detected.

  In the induction heating device according to the eighth aspect of the present disclosure, the control unit according to any one of the first to seventh aspects is configured such that after the object to be heated is detected by the object to be heated detection unit, the object to be heated is detected. The inverter is controlled so that the number of times the detection current is supplied to the heating coil in which the object to be heated is detected is less than that in the heating coil in which the object to be heated is not detected until no heating object is detected. To do.

In the induction heating device of the ninth aspect according to the present disclosure, the heated object detection unit in any one of the first, third, and fifth to eighth aspects is
The first threshold value used when detecting the presence or absence of the object to be heated in a state where no current is supplied to the adjacent heating coil, and the presence or absence of the object to be heated by simultaneously supplying current to the adjacent heating coil Set a second threshold to be used when detecting,
The presence or absence of the object to be heated is detected using the first threshold value or the second threshold value.

In the induction heating apparatus according to the tenth aspect of the present disclosure, the object to be heated detection unit according to any one of the first, third, and 5-9 is
A first threshold value used when detecting the presence or absence of the object to be heated in a state in which no current is supplied to the adjacent heating coil, and the object to be heated while the adjacent heating coil is performing a heating operation with a minimum power. A third threshold value used when detecting the presence or absence of a heated object, and a fourth threshold value used when detecting the presence or absence of the object to be heated in a state where an adjacent heating coil is performing a heating operation with rated power And set
The presence or absence of the object to be heated is detected using any one of the first threshold value, the third threshold value, and the fourth threshold value.

  In the induction heating apparatus according to the eleventh aspect of the present disclosure, the control unit according to any one of the first and fifth to tenth aspects is configured so that the detected current supplied to each heating coil is in the vertical and horizontal directions. The inverter is controlled so as to be opposite between adjacent heating coils.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited by the embodiment. In all the drawings below, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1)
[overall structure]
FIG. 1 is a schematic plan view of the induction heating device 10a according to the first embodiment of the present disclosure, and schematically shows main elements in the first embodiment. FIG. 2 is a longitudinal sectional view of the induction heating device 10a cut along line AA in the schematic plan view of the induction heating device 10a shown in FIG. FIG. 3 is a block diagram illustrating a configuration of the induction heating apparatus 10a according to the first embodiment.

  As shown in FIGS. 1 to 3, the induction heating apparatus 10 a according to the first embodiment applies a high frequency current to the top plate 13, the plurality of heating coils 11 arranged in alignment below the top plate 13, and the heating coils 11. The inverter 16 to be supplied and the control unit 17 that controls the output of the inverter 16 are provided. In addition, the induction heating device 10a according to the first embodiment includes an operation display unit 12 that outputs an operation command to the control unit 17, and also includes an input current and / or an energization path for power transmission from the power source to the heating coil 11. A heated object detection unit 18 is provided that detects the state of the heated object (the presence or absence of the heated object) from the detected value of the output voltage.

Hereinafter, each element which comprises the induction heating apparatus 10a of Embodiment 1 is explained in full detail.
[Top plate]
The induction heating device 10a of the first embodiment has a flat top plate 13 at the top. An object to be heated such as a pan is placed on the top plate 13. For example, as shown in FIGS. 1 and 2, the first heated object 14 and / or the second heated object 15 larger than the first heated object 14 is placed. The top plate 13 is made of an electrical insulator such as glass or ceramic.

[Heating coil]
The heating coil 11 has a multi-coil configuration having a plurality of heating coils. The plurality of heating coils 11 are arranged in a matrix with a predetermined interval immediately below the top plate 13. For example, as shown in FIG. 1, the induction heating device 10 a according to the first embodiment may have a configuration in which a plurality of heating coils 11 are arranged side by side in the vertical direction and in the horizontal direction. In Embodiment 1, it is set as ae row in an order from the row of the heating coil 11 close | similar to the operation display part 12 in FIG. 1, and is defined as ai column in an order from the left column of the induction heating apparatus 10a of FIG. Therefore, in Embodiment 1, the several heating coil 11 is shown with the code | symbol of heating coil 11aa-11ei. In the following description, the same reference numerals are given to the heating coil 11.

  All the heating coils 11 have substantially the same shape and the same configuration. In the induction heating apparatus 10a of the first embodiment, the heating coil 11 performs an induction heating operation.

[Inverter]
The inverter 16 is connected to the plurality of heating coils 11. The inverter 16 supplies a high frequency current to each of the plurality of heating coils 11. The induction heating device 10a according to the first embodiment may be configured to include a plurality of inverters 16 that are respectively connected separately corresponding to the plurality of heating coils 11. For example, the induction heating device 10a of the first embodiment may include inverters 16aa to 16ei connected to the respective heating coils 11aa to 11ei as shown in FIG. Alternatively, in addition to a configuration in which several heating coils 11 are collectively connected to the inverter 16, there is a configuration in which only the heating coil 11 requiring power supply is connected to the inverter 16.

[Control unit]
The control unit 17 is connected to the inverter 16, the operation display unit 12, and the heated object detection unit 18. For example, the control unit 17 receives an operation command instruction from the operation display unit 12 and controls the output of the inverter 16. The control unit 17 receives the detection result from the heated object detection unit 18 and controls the output of the inverter 16.

[Operation display section]
The operation display unit 12 is arranged at the center of the user side (the lower side in FIG. 1) in the top plate 13, and is configured to be easy for the user to use. The operation display unit 12 is not limited to the position illustrated in FIG. 1 and may be disposed at any position as long as the configuration is easy for the user to use.

  The operation display unit 12 is connected to the control unit 17. The operation display unit 12 outputs operation command signals such as start or stop of power supply and power adjustment to the control unit 17.

  For example, when the first heated object 14 such as a pan is placed on the top plate 13, the operation display unit 12 outputs an operation command signal that instructs the start of the heating operation to the control unit 17. To do.

[Heating object detector]
The heated object detection unit 18 is connected to the inverter 16 and the control unit 17. The object to be heated is mounted on the object to be heated 18 based on the detected value of the input current and / or generated output voltage of the power transmission path from the power source to the heating coil 11 such as the inverter 16. The heating coil 11 corresponding to the position is detected. For example, the state of the object to be heated that is magnetically coupled to the heating coil 11 such as whether or not the first object to be heated 14 such as a pan is placed above the energized heating coil 11 (the object to be heated). Presence or absence).

  Further, for example, the heated object detection unit 18 outputs the detection result of the state of the first heated object 14 to the control unit 17 as a signal.

  As described above, in the induction heating device 10a of the first embodiment, as shown in FIG. 1, the first heated object 14 or the second heated object 15 is placed on the top plate 13. The heating coil 11 corresponding to the area where the object to be heated is placed is detected and a heating operation is performed. That is, the induction heating device 10a according to the first embodiment performs a heating operation by detecting the heating coil 11 directly under the object to be heated placed on the top plate 13.

  For example, as shown in FIG. 1, when the first object to be heated 14 is placed on the top plate 13, the induction heating device 10 a according to the first embodiment is below the first object to be heated 14. A high frequency current is supplied to the heating coils 11bb, 11bc, 11cb, and 11cc, and an appropriate induction heating operation is performed on the first object 14 to be heated.

  On the other hand, as shown in FIG. 1, when the second object to be heated 15 is placed on the top plate 13, the induction heating apparatus 10 a according to the first embodiment is directly below the second object to be heated 15. A high frequency current is supplied to the heating coils 11ag, 11ah, 11ai, 11bg, 11bh, 11bi, 11cg, 11ch, and 11ci, and an appropriate induction heating operation is performed on the second object to be heated 15.

[Detection of heated object]
Next, the detection operation of the first object to be heated 14 when the first object to be heated 14 such as a pan is placed on the induction heating device 10a of the first embodiment will be described.

  FIG. 4 illustrates an example of a circuit configuration of the induction heating device 10a according to the first embodiment of the present disclosure. FIG. 5 is an explanatory diagram illustrating the relationship between the input current from the power supply 40 and the output voltage generated in the inverter 16 in the induction heating apparatus 10a according to the first embodiment of the present disclosure. FIG. 5 shows the relationship between the input current and the output voltage for the heated object detector 18 to detect the presence or absence of the heated object in the circuit configuration shown in FIG.

  FIG. 4 shows a circuit of the induction heating device 10a including the heating coil 11, the inverter 16, the control unit 17, the heated object detection unit 18, the AC power supply 40, the current detection unit 48, and the voltage detection unit 49. . The inverter 16 includes a diode bridge 41, a choke coil 42, a smoothing capacitor 43, a first switching element 44, a second switching element 45, a resonance capacitor 46, and a snubber capacitor 47.

  In the circuit configuration shown in FIG. 4, the power source 40 is connected to a diode bridge 41, a choke coil 42, and a smoothing capacitor 43 in order to convert alternating current into direct current and smooth it. In order to supply a high-frequency current to the heating coil 11, a first switching element 44 having a reverse conducting diode and a second switching element 45 also having a reverse conducting diode are connected in series at both ends of the smoothing capacitor 43. It is connected.

  In addition, the second switching element 45 has a switching loss that occurs when the resonance capacitor 46 for causing current resonance with the heating coil 11 and the first switching element 44 and the second switching element 45 are turned off. A snubber capacitor 47 for reduction is connected in parallel.

  Further, in the circuit configuration shown in FIG. 4, the output voltage Vc that is the voltage across the current detection unit 48 for detecting the input current Iin supplied from the power supply 40 to the inverter 16 and the resonance capacitor 46 in the inverter 16 is obtained. A voltage detection unit 49 for detection is provided. Detection values of the current detection unit 48 and the voltage detection unit 49 are output to the heated object detection unit 18.

  Based on the detected value of the input current Iin detected by the current detector 48 and the output voltage Vc detected by the voltage detector 49, the horizontal axis is the input current Iin and the vertical axis is the output voltage Vc, as shown in FIG. The detected values of the input current Iin and the output voltage Vc can be expressed on the coordinate plane.

  For example, in the induction heating apparatus 10a of the first embodiment, the input voltage of the power supply 40 in the circuit configuration shown in FIG. 4 is constant, and the heating region (heating coil 11) of the surface facing the top plate 13 in one heating coil 11 is used. The condition can be set so that the object to be heated detection unit 18 detects the presence of the object to be heated when the object to be heated is placed in an area of 50% or more of the heating area on the upper surface of the object. In the induction heating apparatus 10a of the first embodiment, the input current Iin and the output voltage Vc are changed when the driving variable such as the operating frequency or the duty of the first switching element 44 and the second switching element 45 is changed under this condition. If the detected values of (the voltage across the resonance capacitor 46) have a correlation that affects each other, the threshold curve L shown in FIG. 5 can be drawn by connecting the detected values. In addition, the induction heating apparatus 10a of Embodiment 1 has conditions such that, for example, when an object to be heated is placed in an area of 40% or more of the heating area on the upper surface of the heating coil 11, the presence of the object to be heated is detected. May be set. That is, the induction heating apparatus 10a according to the first embodiment can arbitrarily set the conditions for detecting the presence or absence of an object to be heated.

  The threshold curve L includes a state where the heating coil 11 can heat the object to be heated (a state where the object to be heated is above the heating coil 11) and a state where the heating coil 11 cannot be heated (a state where there is no object to be heated above the heating coil 11). Indicates the boundary. On the coordinate plane shown in FIG. 5, a region 1 (region on the right side of the threshold curve L) indicates a state in which the heating coil 11 can heat the object to be heated, and a region 2 (region on the left side of the threshold curve L) is heated. The state where the coil 11 cannot be heated is shown.

  For example, if an object to be heated is not placed above the heating coil 11, the output voltage Vc increases with respect to the input current Iin.

  Therefore, a threshold curve L is drawn at the boundary between the state in which the heating coil 11 can heat the object to be heated and the state in which it cannot be heated, and heating is possible if the detected values of the input current Iin and the output voltage Vc are in the region 1 in FIG. It is determined that there is a heated object, and if it is in region 2, it can be determined that heating is not possible (no object to be heated). In this way, the object to be heated detection unit 18 is heated on the heating coil 11 based on the input current of the power transmission path from the power supply 40 to the heating coil 11 and / or the detected value of the generated output voltage. It is possible to detect whether or not is mounted.

  FIG. 6 is a time chart of the detection operation of the object to be heated by the induction heating device 10a according to the first embodiment of the present disclosure. FIG. 6 shows a detection current for detecting the presence / absence of an object to be heated in each of a plurality of heating coils 11 arranged in order to detect placement of the object to be heated (presence / absence of an object to be heated). An example of the time chart when supplying is shown.

  As shown in FIG. 6, the induction heating apparatus 10a of Embodiment 1 first performs a detection operation (energization) for the detection period Td in the heating coil 11aa in the detection cycle Tc1 of the object to be heated. That is, the induction heating device 10a according to the first embodiment supplies a detection current for detecting the presence or absence of an object to be heated to the heating coil 11aa for the detection period Td. The induction heating device 10a of the first embodiment detects whether or not an object to be heated is placed above the heating coil 11aa during the detection period Td. For example, the presence or absence of an object to be heated is determined based on whether the detected values of the input current Iin and the output voltage Vc of the heating coil 11aa belong to the region 1 or the region 2 in FIG.

  When the detection period Td of the heating coil 11aa elapses, the induction heating device 10a of the first embodiment stops the detection operation to the heating coil 11aa and starts the detection operation to the heating coil 11ba, and the upper part of the heating coil 11ba. Whether or not the object to be heated is placed on is detected in the same manner as the heating coil 11aa.

  The detection operation for detecting the presence or absence of an object to be heated can be performed before the control unit 17 receives a signal of an operation command (heating operation start command) instructing the start of the heating operation from the operation display unit 12. it can. For example, the induction heating device 10a of the first embodiment may start the detection operation when the power switch is turned on, or the detection operation when the human sensor detects a person near the induction heating device 10a. You may start.

  The induction heating device 10a according to the first embodiment allows the user of the induction heating device 10a to place the object to be heated, for example, whether or not the object to be heated is placed, and grasp the shape of the object to be heated. Information necessary for selecting the heating operation of the object to be heated can be displayed on the operation display unit 12 when the heating operation is instructed. As a result, it is possible to provide the induction heating device 10a that is convenient for the user.

  By performing this detection operation with all of the plurality of heating coils 11, the state of the object to be heated can be detected with each heating coil 11 for each detection cycle Tc1. Therefore, the induction heating apparatus 10a of Embodiment 1 grasps the placement state of the object to be heated by the object detection unit 18 and, for example, displays the region where the object to be heated is placed on the operation display unit 12. By displaying on the screen, the user can easily perform the heating operation. Therefore, the user operates the heating operation on the operation display unit 12 to supply power only to the heating coil 11 in which the object to be heated is detected, that is, the heating coil 11 immediately below the object to be heated. It can be operated so as to heat only the heated object.

  Moreover, with respect to the heating coil 11 in which the to-be-heated material is not mounted, danger that it will heat from the time of mounting the pan placed after operation by preventing heating operation from being started. Can be eliminated. In the induction heating device 10a of the first embodiment, only the detection operation is performed in the heating coil 11 corresponding to the region where the object to be heated is not placed, that is, the heating coil 11 not directly under the object to be heated. For example, even if another object to be heated is placed in a region other than the heating coil 11 performing the heating operation, the heating operation is performed as long as the heating operation is not performed on the other object to be heated. Absent. As described above, the induction heating apparatus 10a according to Embodiment 1 detects the heating coil 11 corresponding to the region where the object to be heated is placed, and then the object to be heated until the user operates the heating operation. The heating is not started.

  In the detection operation, when a high-frequency current is continuously supplied to the heating coil 11 on which the object to be heated is not placed for a long time, the leakage magnetic field increases. Alternatively, supplying a detection current for detecting the presence or absence of an object to be heated to the heating coil 11 causes a decrease in efficiency due to conduction loss. However, the induction heating apparatus 10a according to the first embodiment prevents a leakage magnetic field from increasing and suppresses deterioration in efficiency by supplying a small detection current at a constant interval in a short time in the detection operation. it can.

  As shown in FIG. 6, in the first embodiment, an operation for detecting an object to be heated is performed so that a plurality of heating coils 11 are not energized simultaneously. That is, in the first embodiment, the detection current for detecting the presence or absence of the object to be heated is not supplied to the plurality of heating coils 11 at the same time. Thereby, the magnetic field which generate | occur | produces when the other heating coil 11 performs the detection operation of a to-be-heated object does not link and interfere with its own heating coil 11. Therefore, the induction heating device 10a of the first embodiment can detect the object to be heated with high accuracy because the detection values of the input current Iin and the output voltage Vc do not vary.

  The induction heating device 10a of the first embodiment sequentially performs the detection operation of the object to be heated by the plurality of heating coils 11. That is, the induction heating device 10a of the first embodiment sequentially supplies a detection current for detecting the presence or absence of an object to be heated to the plurality of heating coils 11, thereby peaking the power necessary for the operation for detecting the object to be heated. The value can be reduced. As a result, the induction heating device 10a of the first embodiment can reliably detect the pan without exceeding the rated power.

  FIG. 7 is another time chart of the detection operation of the object to be heated by the induction heating apparatus 10a according to the first embodiment of the present disclosure. As shown in FIG. 7, the induction heating device 10 a according to the first embodiment has a period Tcm in which the detection operation is performed and a period Tcp in which none of the heating coils 11 perform the detection operation in the detection cycle Tc2. Also good.

  As described above, the induction heating device 10a according to the first embodiment can adjust the length of the detection cycle Tc2 by having the period Tcp during which the detection operation is not performed. For example, if the period Tcm during which the detection operation is performed is constant, the detection cycle Tc2 can be lengthened by setting the period Tcp during which the detection operation is not performed to be long. As a result, the induction heating device 10a of the first embodiment reduces the time during which the detection operation is performed for the detection cycle Tc2, that is, the time during which the detection current is supplied to the heating coil 11, and the average power consumption is reduced. Thus, power loss can be reduced.

  Further, for example, the induction heating device 10a according to the first embodiment performs heating between the detection operation of the object to be heated by the heating coil 11aa and the detection operation of the object to be heated by the heating coil 11ba adjacent to the heating coil 11aa. A period Tcp during which the detection operation of the coil 11 is not performed may be inserted for a certain time. The length of the period Tcm and the length of the period Tcp are not limited to the length shown in FIG. 7, and may be arbitrarily set.

  As described above, by detecting the adjacent heating coils 11 at the same time, it is possible to detect a heated object such as a pan so that the magnetic fields generated from the respective heating coils 11 do not interfere with each other. it can.

(Embodiment 2)
Hereinafter, the induction heating apparatus 10b of Embodiment 2 will be described with reference to the drawings.

  Here, in the second embodiment, only the parts different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted.

  FIG. 8 is a diagram showing a time chart of the detection operation of the object to be heated of the induction heating device 10b according to the second embodiment of the present disclosure, and is arranged in order to detect the placement of the object to be heated. An example of a time chart when the detection operation is performed in each of the plurality of heating coils 11 is shown.

  As shown in FIG. 8, the second embodiment is different from the first embodiment in that the detection operation is simultaneously performed with a plurality of heating coils. In the second embodiment, the detection operation of the object to be heated is simultaneously performed by several heating coils 11 that are not adjacent to each other among the plurality of heating coils 11 in the detection period Td.

  As shown in FIG. 8, for example, in the configuration shown in FIG. 1, the heating coil 11 that performs the detection operation simultaneously in the first detection period Td during the detection cycle Tc3 has two heating coils 11aa each in row a. , 11ad, 11ag are three non-adjacent heating coils. Here, among these three heating coils 11aa, 11ad, and 11ag, attention is paid to the heating coil 11aa and the heating coil 11ad, for example. As shown in FIG. 1, between the two heating coils 11aa and 11ad that perform the detection operation, there are two heating coils 11ab and 11ac that do not perform the detection operation.

  That is, the distance between the heating coils 11aa and 11ad that are simultaneously detecting (energizing) is twice as long as the diameter of the heating coil 11. Since the magnetic field propagation strength in the air is inversely proportional to the nth power of the distance (n is 2 or more), the interference strength of the magnetic field is greatly reduced as the distance increases.

  According to the experiments by the inventors, if there is at least one heating coil 11 that does not perform detection (does not energize) between two heating coils 11aa and 1ad that perform detection (energization), detection of an object to be heated is possible. It has been confirmed that the accuracy is improved to a level where there is no trouble caused by interference.

  The distance between the two heating coils 11aa and 11ad that are performing the detection operation varies depending on the diameter of the heating coil 11. However, as the diameter of the heating coil 11 becomes smaller, the power that can be supplied from the heating coil 11 to the object to be heated, that is, the generated magnetic flux, becomes smaller. Detection of a heated object can be performed with high accuracy.

  Further, in the detection period Td, a detection current for detecting the presence or absence of the object to be heated is supplied in order to detect whether or not the object to be heated is placed above each heating coil 11 ( This is the period during which power is supplied. For example, if the power source 40 is a 50 Hz AC power source, the detection period Td needs to be at least about 10 milliseconds. When the detection accuracy of the object to be heated is increased, the detection period Td requires a longer time. Therefore, when the detection current is sequentially supplied to the plurality of heating coils 11 as in the first embodiment, the detection period Tc1 is long. Become.

  However, when the detection operation is simultaneously performed by the plurality of heating coils 11 as in the second embodiment, the plurality of heatings at a distance at which the detection accuracy of the object to be heated does not decrease due to the interference of the magnetic field generated by the other heating coils 11. If the detection operation is performed by the coil 11, the detection cycle Tc3 required when performing the detection operation at the same time can be shortened. For example, the detection cycle Tc3 of the second embodiment can be made shorter than the detection cycle Tc1 that is necessary when the detection operation is performed independently in the first embodiment.

  For this reason, the induction heating device 10b according to the second embodiment can shorten the longest time (detection cycle Tc3) from when the object to be heated is placed until it is detected. The state (for example, the shape of the object to be heated, the placement position, etc.) can be quickly displayed. Thereby, the user can provide an easy-to-use induction heating apparatus that can start a heating operation smoothly without stress.

  In the induction heating apparatus 10b according to the second embodiment of the present disclosure, in the configuration illustrated in FIG. 1, the detection of the object to be heated is simultaneously performed by every two heating coils 11aa, 11ad, and 11ag in the horizontal direction in the row a. Yes. In addition, for example, in the configuration shown in FIG. 1, the detection operation of the object to be heated may be simultaneously performed by every other heating coil 11aa, 11ac, 11ae, 11ag in the horizontal direction in row a. In the configuration shown in FIG. 1, the detection operation of the object to be heated may be simultaneously performed by the heating coils 11aa and 11ca arranged alternately in the vertical direction in the row a. As described above, the induction heating device 10b according to the second embodiment does not limit the order and the number of objects to be detected unless the objects to be heated are simultaneously detected by the adjacent heating coils 11. Absent.

  The induction heating device 10b according to the second embodiment may perform an operation of detecting an object to be heated before the control unit 17 receives an operation command signal that instructs the start of the heating operation from the operation display unit 12. Note that the current value of the detection current for detecting the presence or absence of the object to be heated supplied to the heating coil 11 is smaller than the current value of the heating current for performing the heating operation supplied to the heating coil 11.

(Embodiment 3)
Hereinafter, the induction heating apparatus 10c of Embodiment 3 is demonstrated with reference to drawings.

  Here, in the third embodiment, only portions different from the first embodiment or the second embodiment will be described, and the description of the same portions as the first embodiment or the second embodiment will be omitted.

  FIG. 9 is a time chart of the detection operation and the heating operation of the heated object of the induction heating device 10c according to the third embodiment of the present disclosure, and an example of the time chart before and after the heating of the first heated object 14 is started. Show.

  In the third embodiment, as shown in FIG. 9, is the object to be heated placed on the top plate 13 of the induction heating device 10c before the time Ts for starting the heating of the first object to be heated 14? This is different from the first or second embodiment in that an operation for detecting whether or not is performed. In the third embodiment, the operation for detecting whether or not the object to be heated is placed on the top plate 13 is the same as that in the first or second embodiment.

  Here, the case where the 1st to-be-heated material 14 is mounted in the position shown in FIG. 1 before the time Ts is demonstrated. The heated object detection unit 18 detects that the heated object is placed above the heating coils 11bb, 11cb, 11bc, and 11cc shown in FIG. 1 by the detection operation of the heated object. Even if the induction heating device 10c according to the third embodiment detects the object to be heated above the heating coil 11, it continues the detection operation of the object to be heated unless the operation display unit 12 outputs a signal instructing the heating operation. In this way, the control unit 17 controls. This is because the first heated object 14 is detected again when the first heated object 14 placed on the top plate 13 of the induction heating device 10c moves.

  When the control unit 17 receives an operation command signal for instructing the start of the heating operation from the operation display unit 12 at the time Ts, a high-frequency current for performing the heating operation is supplied to the heating coils 11bb, 11cb, 11bc, and 11cc. Thus, the inverter 16 is controlled. Thus, when the operation command signal for instructing the start of the heating operation is output from the operation display unit 12, the heating operation is started and the detection operation is stopped in the heating coils 11bb, 11cb, 11bc, and 11cc.

  On the other hand, for example, the heating coil 11dc adjacent to the heating coil 11cc performing the heating operation has no object to be heated (because it is not detected), so the heating coil 11dc continues the detection operation of the object to be heated. To do. That is, even if the heating coils 11bb, 11cb, 11bc, and 11cc immediately below the first object to be heated 14 placed on the induction heating device 10c start the heating operation, the heating coils that perform the heating operation The heating coils 11 other than 11bb, 11cb, 11bc, and 11cc continue to detect the object to be heated. Even if an object to be heated different from the first object to be heated 14 is placed above the heating coil 11dc, and the object to be heated detection unit 18 detects the object to be heated, the operation display unit 12 Unless a signal instructing the heating operation is output, the heating coil 11dc continues the operation of detecting the object to be heated.

  Thus, even if the induction heating apparatus 10c of Embodiment 3 starts a heating operation with the heating coil 11 in a certain region, this heating operation hinders detection of an object to be heated with the heating coil 11 in another region. do not do. Therefore, in Embodiment 3, it is possible to provide an easy-to-use induction heating apparatus that maintains the detection frequency and detection accuracy of the object to be heated.

  Further, when detecting the object to be heated, it is necessary to supply a detection current for detecting the presence or absence of the object to be heated to the heating coil 11, so that a conduction loss occurs due to the detection current supplied to the heating coil 11. . In addition, when an object to be heated is placed above the heating coil 11, a magnetic field is generated even with a minute current for the detection operation, so that minute induction heating is performed. Due to these conduction losses and induction heating, electric power P1 is supplied from the power supply 40 and consumed.

  However, the supply and consumption of the electric power P1 by these are not preferable. Therefore, when operating the inverter 16 to detect the object to be heated, the electric power for detecting the presence or absence of the object to be heated is the electric power that can detect the placement state of the object to be heated, and as much as possible. It is desirable that a small amount of power is supplied to the heating coil 11.

  Therefore, Embodiment 3 controls the inverter 16 so that the electric power P1 supplied during the detection operation of the heated object is smaller than the electric power P2 supplied during the heating operation of the heated object. It is possible to increase the efficiency of the induction heating device 10c by suppressing power consumption due to the detection operation.

(Embodiment 4)
Hereinafter, the induction heating apparatus 10d of Embodiment 4 will be described with reference to the drawings.

  Here, in the fourth embodiment, only the parts different from the first to third embodiments will be described, and the description of the same parts as the first to third embodiments will be omitted.

  FIG. 10 is a time chart of the detection operation and the heating operation of the heated object of the induction heating device 10d according to the fourth embodiment of the present disclosure, and an example of the time chart before and after the heating of the first heated object 14 is started. Show.

  In FIG. 10, after the time Ts for starting the heating of the first object to be heated 14 placed at the position shown in FIG. 1, the heating coil 11dc, that is, the heating coil adjacent to the heating coil that is performing the heating operation is used. Is different from FIG. 9 in that the detection operation of the object to be heated is not performed.

  The operating frequency of the inverter 16 when detecting the presence or absence of the object to be heated is set to be higher than the operating frequency of the inverter 16 when the object to be heated is heated.

  This is because, when detecting the presence or absence of an object to be heated, for example, the power supplied from the power supply 40 can be reduced by separating the operating frequency of the inverter 16 from the resonant frequency of the heating coil 11 and the resonant capacitor 46.

  The width of the operating frequency of the inverter 16 when detecting the presence or absence of the object to be heated and the width of the operating frequency of the inverter 16 when heating the object to be heated are set apart from each other by about 20 kHz which is an audible frequency difference.

  For example, when the first object to be heated 14 is heated at the position shown in FIG. 1, it is disposed adjacent to the heating coil 11 cc that supplies a high-frequency current to heat the first object to be heated 14. A magnetic field generated from the heating coil 11cc interferes with the heating coil 11dc.

  However, as described above, the frequency of the heating current of the heating coil 11cc performing the heating operation and the frequency of the detection current of the heating coil 11dc performing the detection operation are different. Therefore, the influence on the detection accuracy due to the interference of the magnetic field is small compared to the case where the frequency is the same (when both the heating coils 11 cc and 11 dc are detecting), and the detection of the object to be heated is not possible. Is possible.

  For example, when it is necessary to detect an object to be heated with higher accuracy, for example, in order to accurately detect a minute shift of the object to be heated, heating close to the heating coils 11bb, 11cb, 11bc, and 11cc that are performing the heating operation. The coil, for example, the heating coil 11 dc or the like does not perform the detection operation of the object to be heated and does not allow the heating operation. That is, the heating coil 11dc or the like that is difficult to detect the object to be heated accurately does not perform the object detection operation, thereby maintaining the accuracy of the object detection operation as the entire induction heating device 10d. Can do. In addition, if there is one heating coil 11dc that does not perform the detection operation of the object to be heated, the interference intensity of the magnetic field from the heating coil 11cc to the heating coil 11ec disposed with the heating coil 11dc interposed therebetween is greatly reduced. Since the accuracy of the detection operation of the object to be heated can be ensured, the heating coil 11ec can continue the detection operation.

  In addition, when the 1st to-be-heated object 14 is heated, when the 2nd to-be-heated object 15 different from the 1st to-be-heated object 14 is mounted on the top plate 13, a heating area is vast and In the induction heating apparatus having a multi-coil configuration in which the placement area is free, it is not necessary to place the second object to be heated 15 at a position close to the first object to be heated 14. Absent.

(Embodiment 5)
Hereinafter, the induction heating apparatus 10e of Embodiment 5 is demonstrated with reference to drawings.

  Here, in the fifth embodiment, only parts different from the first to fourth embodiments will be described, and the description of the same parts as the first to fourth embodiments will be omitted.

  FIG. 11 is a schematic plan view of an induction heating device 10e according to the fifth embodiment of the present disclosure, and schematically shows main elements in the fifth embodiment.

  11 is different from FIG. 1 in that it has a heating coil group. In Embodiment 5, a plurality of heating coils 11 are divided into three heating coil groups G1, G2, and G3, and an operation for detecting an object to be heated is performed.

  FIG. 12 is a schematic diagram of the induction heating apparatus 10e according to the fifth embodiment of the present disclosure when the 45 heating coils shown in the schematic plan view of FIG. 11 are divided into three heating coil groups G1, G2, and G3. It is a time chart of detection operation of a heating thing. FIG. 12 shows an example of a time chart of the detection operation of the object to be heated.

  In FIG. 12, it differs from FIGS. 6-8 by the point which performs the detection operation of a to-be-heated object simultaneously with all the heating coils 11 in the same group containing an adjacent heating coil.

  When detecting an object to be heated, if a current flows through the adjacent heating coil, a magnetic field is generated from the adjacent heating coil, and the magnetic field interferes with another heating coil that performs the detection operation of the object to be heated. . Then, a current caused by Lenz's law flows through the heating coil that performs the detection operation of the object to be heated, and an error occurs in the current value and voltage value used to determine the presence or absence of the object to be heated, thereby detecting the object to be heated. The operation could not be performed accurately.

  However, if the failure is caused by interference of the magnetic field generated from the heating coil incorporated in the same induction heating device, the error level generated when the detection current and magnetic field supplied to the adjacent heating coil interfere. Can be measured in advance. For this reason, it is possible to set a threshold value (current and voltage threshold values) for determining the object to be heated that does not appear to be affected even if it receives magnetic field interference from adjacent heating coils. Accordingly, it becomes possible to simultaneously detect the object to be heated by the adjacent heating coils 11 without the mistake of determining the object to be heated due to the interference of the magnetic field.

  As shown in FIG. 11, in the fifth embodiment, for example, 45 heating coils are divided into three heating coil groups G1, G2, and G3. Then, as shown in FIG. 12, for example, all the heating coils 11aa to 11ec in the heating coil group G1 simultaneously perform the detection operation of the object to be heated during the detection period Td. As a result, the detection cycle Tc4 necessary for performing the detection operation of the object to be heated by all the heating coils 11 on the induction heating apparatus 10e of the fifth embodiment is the detection operation of the object to be heated by one heating coil 11. It can be suppressed to about three times the detection cycle Td required for As another example, the detection cycle Tc4 of the induction heating device 10e of the fifth embodiment is 1/5 of the detection cycle Tc3 of the second embodiment. As described above, the induction heating device 10e according to the fifth embodiment can shorten the time during which the object to be heated is being detected. As a result, it is possible to quickly detect an object to be heated and provide an induction heating apparatus with good responsiveness.

  In particular, the induction heating apparatus 10e of the fifth embodiment simultaneously detects adjacent heating coils in order to determine the shape and position of the object to be heated in a transient state in which the object to be heated is moved on the induction heating apparatus. It is desirable to do.

  For example, when the detection current for detecting the presence or absence of the object to be heated is sequentially supplied to the plurality of heating coils 11 as in the first embodiment, the object to be heated detection unit 18 has the shape and placement of the object to be heated. There is a possibility of misidentification of position. For example, in the induction heating apparatus 10 according to the first embodiment, the object to be heated moves immediately after it is determined that the object to be heated is not placed by a certain heating coil, and the object to be heated is placed on the heating coil. Even if it is done, it will be discriminate | determined that the to-be-heated material is not mounted in the said heating coil. On the other hand, in other heating coils that perform detection operation at a timing later than the detection operation timing of the heating coil, there is a possibility of detecting an object to be heated after moving. As described above, when the detection current is sequentially supplied to the plurality of heating coils 11, the heated object detection unit 18 may make a determination error in the shape and placement position of the heated object. In the induction heating apparatus 10e, the detection operation is simultaneously performed for all the heating coils in the same heating coil group, so that the shape or placement position of the object to be heated can be prevented from being erroneously determined.

  Note that it is effective to determine the shape and position of an object to be heated by using only one heating coil group, that is, performing detection operation on all 45 heating coils at the same time. The number of heating coil groups is set so that the power required for the power supply does not exceed at least the rated power. In addition, although the induction heating apparatus 10e of Embodiment 5 performs detection operation simultaneously with all the heating coils 11 in a heating coil group, it performs sequential detection operation with the several heating coil 11 of a heating coil group. You may do it.

(Embodiment 6)
Hereinafter, the induction heating apparatus 10f according to the sixth embodiment will be described with reference to the drawings.

  Here, in the sixth embodiment, only the parts different from the first to fifth embodiments will be described, and the description of the same parts as the first to fifth embodiments will be omitted.

  FIG. 13 is a time chart of the detection operation of the object to be heated by the induction heating device 10f according to the sixth embodiment of the present disclosure, and shows an example of the time chart of the detection operation of the object to be heated.

  13 differs from FIG. 12 in that the detection operation is continuously performed until the heated object is removed in the heating coil that has detected the heated object. After detecting the object to be heated, the induction heating device 10f according to the sixth embodiment continues to supply a detection current for detecting the object to be heated to the heating coil until no object to be heated is detected in the heating coil. .

  When performing the operation of detecting the object to be heated, the inverter 16 connected to the heating coil 11 is driven to supply a detection current for detecting the object to be heated to the heating coil 11. An inrush current flows through the heating coil 11 at the timing when the detection current is started to be supplied to the heating coil 11 from the state where the detection operation of the object to be heated is not performed, that is, the detection current is not supplied to the heating coil 11. The magnetic field generated by the inrush current and the object to be heated resonate to generate a squealing sound.

  Therefore, if the detection operation of the object to be heated is periodically performed even after the object to be heated is placed on the induction heating device, an irritating sound is generated every time the detection operation of the object to be heated is performed. And discomfort to the user.

  However, as shown in FIG. 13, the induction heating apparatus 10f of the sixth embodiment, for example, places the object to be heated on the heating coils 11bb and 11cb shown in FIG. 1 at least at the timing Tp1. The detection operation is continued only with the heating coils 11bb and 11cb that have detected the object to be heated by the detection operation. That is, in the sixth embodiment, it is possible to realize an induction heating device that does not generate an irritating sound by “continually” by supplying a current of a detection level necessary for the detection operation to the heating coils 11bb and 11cb.

  In addition, as shown in FIG. 13, after the timing Tp1 when the object to be heated is placed on the heating coils 11bb and 11cb shown in FIG. This is because the processing time for the object to be heated is necessary. Inductive heating device 10f of the sixth embodiment may supply a continuous current to heating coils 11bb and 11cb immediately after timing Tp1 when the object to be heated is placed, when high-speed processing is possible.

  Further, from the viewpoint of not emitting the leakage magnetic field wastefully and improving the power efficiency, as shown in FIG. 13, the continuous current supplied to the heating coils 11bb and 11cb at the same time as the timing Tp2 when the object to be heated is removed is also obtained. It is desirable to stop. Further, the induction heating device 10f according to the sixth embodiment can quickly perform the next detection operation of the heated object by returning to the normal detection operation of the heated object after the timing Tp2.

(Embodiment 7)
Hereinafter, the induction heating apparatus 10g according to the seventh embodiment will be described with reference to the drawings.

  Here, in the seventh embodiment, only the parts different from the first to sixth embodiments will be described, and the description of the same parts as the first to sixth embodiments will be omitted.

  FIG. 14 is a time chart of the detection operation of the object to be heated by the induction heating device 10g according to the seventh embodiment of the present disclosure, and shows an example of the time chart of the detection operation of the object to be heated.

  14 differs from FIG. 13 in that the frequency of the detection operation of the heated object is reduced until the heated object is removed in the heating coil that detects the heated object. The induction heating device 10g according to the seventh embodiment supplies the detection current for detecting the object to be heated to the heating coil until the object to be heated is not detected in the heating coil after detecting the object to be heated. Is reduced.

  When performing the operation of detecting the object to be heated, the inverter 16 connected to the heating coil 11 is driven to supply a detection current for detecting the object to be heated to the heating coil 11. An inrush current flows through the heating coil at the timing when the detection current starts to be supplied to the heating coil 11 from the state where the detection operation of the object to be heated is not performed, that is, the detection current is not supplied to the heating coil 11. The magnetic field generated by the inrush current and the object to be heated resonate to generate a squealing sound.

  Therefore, if the detection operation of the object to be heated is periodically performed even after the object to be heated is placed on the induction heating device, an irritating sound is generated every time the detection operation of the object to be heated is performed. And discomfort to the user.

  In the seventh embodiment, as shown in FIG. 14, for example, when an object to be heated is placed on at least the heating coils 11bb and 11cb in the configuration shown in FIG. 1 at timing Tp1, the object to be heated is detected by the detection operation of the object to be heated. Only the heating coils 11bb and 11cb that have detected the object reduce the frequency (number of times) of the detection operation of the object to be heated. As a result, it is possible to realize the induction heating apparatus 10g in which the number of occurrences of annoying sound “katsu” is reduced.

  In addition, when the induction heating apparatus 10g according to the seventh embodiment detects that the object to be heated is no longer placed on the heating coils 11bb and 11cb, the induction heating apparatus 10g performs a normal object after the timing Tp2 when the object to be heated is no longer placed. By returning to the operation for detecting the heated object, the next operation for detecting the object to be heated can be quickly performed.

(Embodiment 8)
Hereinafter, the induction heating apparatus 10h according to the eighth embodiment will be described with reference to the drawings.

  Here, in the eighth embodiment, only portions different from the first to seventh embodiments will be described, and the description of the same portions as the first to seventh embodiments will be omitted.

  FIG. 15 is an explanatory diagram illustrating a relationship between the input current Iin from the power supply 40 and the output voltage Vc generated in the inverter 16 in the induction heating apparatus 10h according to the eighth embodiment of the present disclosure. FIG. 15 shows the relationship between the input current Iin and the output voltage Vc for the heated object detector 18 to detect the heated object in the circuit configuration shown in FIG.

  FIG. 15 shows two threshold curves indicating the relationship between the input current value Iin from the power source 40 and the threshold value of the output voltage value Vc generated in the inverter 16 in order to determine whether or not an object to be heated is placed. It differs from FIG. 5 in that it is drawn. Induction heating apparatus 10h according to the eighth embodiment detects the presence or absence of an object to be heated using two threshold curves.

  When the detection operation of the object to be heated is performed, a detection current is supplied to the adjacent heating coil 11, whereby a magnetic field is generated from the adjacent heating coil 11, and the heating coil 11 performs the detection operation of the object to be heated. Interfere with. Then, current due to Lenz's law is supplied to the heating coil 11 that performs the detection operation of the object to be heated, and an error occurs in the input current value and output voltage value used to determine the presence or absence of the object to be heated. The detection of the heated object could not be performed accurately.

  However, if the failure is caused by the magnetic field generated from the heating coil 11 incorporated in the same induction heating apparatus, it is possible to measure in advance the error level generated when the current flowing through the adjacent heating coil 11 interferes with the magnetic field. It is. FIG. 15 shows a region 1 for determining that the object to be heated is placed from the input current value and output voltage value generated when the inverter 16 is driven, and a region 2 for determining that the object to be heated is not placed. Two threshold curves connecting the boundary values are shown. The two threshold curves are a solid line L1 that is applied when the magnetic field interference from the adjacent heating coil 11 is not received, and a broken line L2 that is applied when the magnetic field interference is received from the adjacent heating coil 11. Note that the threshold curve L2 is a boundary value that distinguishes between the region 1 and the region 2 obtained by measuring in advance an error level generated when the current and magnetic field flowing through the adjacent heating coils 11 interfere with each other. It is a line.

  The induction heating apparatus 10h according to the eighth embodiment depends on whether or not the adjacent heating coil 11 performs the detection operation of the object to be heated at the same time, that is, the boundary value of the region to be determined, that is, the threshold curves L1 and L2 shown in FIG. Can be used properly. By these threshold curves L1 and L2, the induction heating apparatus 10h according to the eighth embodiment can accurately determine the object to be heated. For example, the first threshold value is used when detecting an object to be heated on the heating coil 11 in a state where the detection current is not supplied to the adjacent heating coil 11, and the detection current is simultaneously supplied to the adjacent heating coil. The second threshold value is used when detecting an object to be heated on the heating coil 11.

  In the eighth embodiment, the relationship between the input current Iin from the power supply 40 and the output voltage Vc generated in the inverter 16 is used as a value for determining the object to be heated. However, other variables may be used as long as the object to be heated can be determined, such as the operating frequency and conduction time of the switching element.

(Embodiment 9)
Hereinafter, the induction heating apparatus 10i of Embodiment 9 will be described with reference to the drawings.

  Here, in the ninth embodiment, only the parts different from the first to eighth embodiments will be described, and the description of the same parts as the first to eighth embodiments will be omitted.

  FIG. 16 is an explanatory diagram illustrating a relationship between the input current Iin from the power supply 40 and the output voltage Vc generated in the inverter 16 in the induction heating device 10i according to the ninth embodiment of the present disclosure. FIG. 16 shows the relationship between the input current Iin and the output voltage Vc for the heated object detector 18 to detect the heated object in the circuit configuration shown in FIG.

  The ninth embodiment is different from FIG. 15 in that three lines indicating the relationship between the input current value Iin from the power supply 40 and the threshold value of the output voltage value Vc generated in the inverter 16 are drawn in FIG.

  When performing an operation for detecting an object to be heated, if a current is supplied to the adjacent heating coil 11, a magnetic field is generated from the adjacent heating coil 11, and the magnetic field is applied to the heating coil 11 that performs an operation for detecting the object to be heated. have a finger in the pie. Then, current due to Lenz's law is supplied to the heating coil 11 that performs the detection operation of the object to be heated, and an error occurs in the input current value Iin and the output voltage value Vc that are used to determine the presence or absence of the object to be heated. Therefore, the detection operation of the object to be heated could not be performed accurately.

  However, if the failure is caused by a magnetic field generated from a heating coil incorporated in the same induction heating device, the error level generated when the current and magnetic field supplied to the adjacent heating coil 11 interfere with each other can be measured in advance. Is possible. FIG. 16 determines the region 1 where it is determined that the object to be heated is placed from the input current value Iin and the output voltage value Vc generated when the inverter 16 is driven, and that the object to be heated is not placed. Three lines connecting the boundary values of region 2 are shown. The three lines respectively represent a solid line L1 applied when no magnetic field interference is received from the adjacent heating coil 11, and a magnetic field interference from the adjacent heating coil 11 when the adjacent heating coil 11 is in a heating operation. The broken line L3 applied when receiving a small amount (at the time of heating operation at the minimum power) and when the adjacent heating coil 11 is undergoing a heating operation and greatly receiving magnetic field interference from the adjacent heating coil 11 (at the rated power) This is a broken line L4 applied during the heating operation.

  Induction heating apparatus 10i of the ninth embodiment depends on whether adjacent heating coil 11 is performing a heating operation, and if so, whether it is heating at low power or high power. The threshold curves L1, L3, and L4 indicating the boundary values for discriminating between the region 1 and the region 2 can be properly used. By properly using these threshold curves L1, L3, and L4, the induction heating device 10i of the ninth embodiment can accurately determine the object to be heated. For example, the first threshold value is used when an object to be heated is detected in a state where the detection current is not supplied to the adjacent heating coil 11. And the state where the 3rd threshold value is used when detecting an object to be heated while the adjacent heating coil 11 is performing the heating operation with the minimum power, and the adjacent heating coil is performing the heating operation with the rated power The fourth threshold is used when detecting an object to be heated.

  As a value for discriminating the object to be heated, the relationship between the settlement current Iin from the power supply 40 and the output voltage Vc generated in the inverter 16 is used in the ninth embodiment, but the operating frequency and conduction time of the switching element are used. Other variables may be used as long as the object to be heated can be discriminated.

(Embodiment 10)
Hereinafter, the induction heating apparatus 10j of Embodiment 10 will be described with reference to the drawings.

  Here, in the tenth embodiment, only the parts different from the first to ninth embodiments will be described, and the description of the same parts as the first to ninth embodiments will be omitted.

  FIG. 17 is an explanatory diagram showing the direction of the detected current of the heating coil 11 in the induction heating device 10j according to the tenth embodiment of the present disclosure, and shows the relationship of the direction of the detected current with the surrounding heating coil 11. ing.

  The induction heating device 10j according to the tenth embodiment detects the presence or absence of an object to be heated in the plurality of heating coils 11 before receiving an operation command signal instructing the start of the heating operation from the operation display unit 12. An electric current is supplied to detect an object to be heated. Therefore, the induction heating device 10j supplies a minute current to the heating coil even when an object to be heated is not placed.

  When a detection current is supplied to the heating coil 11 on which the object to be heated is not placed, there is no object that absorbs the magnetic field generated from the heating coil 11, so that the generated magnetic field propagates around the induction heating device. . This propagating magnetic field can adversely affect other electronic devices, such as electromagnetic interference, causing damage to the electronic devices or making normal operations difficult (malfunctions). It is desirable to reduce the level of the magnetic field.

  As shown in FIG. 17, for example, in the configuration shown in FIG. 1, the induction heating device 10j according to the tenth embodiment performs the detection operation of the object to be heated simultaneously with the four heating coils 11aa, 11ba, 11ab, and 11bb. The current Iaa of the heating coil 11aa is clockwise. On the other hand, the currents Iba and Iab of the heating coils 11ba and 11ab adjacent to the heating coil 11aa in the vertical and horizontal directions are counterclockwise. As described above, in the induction heating device 10j according to the tenth embodiment, the current direction is reversed (phase difference = π) between the heating coil 11aa and the heating coils 11ba and 11ab adjacent to the heating coil 11aa in the vertical and horizontal directions. ing.

  Thereby, the direction of the magnetic field generated in the surroundings by supplying the detection current to the heating coil 11 is reversed between the heating coils adjacent in the vertical and horizontal directions, so that the magnetic fields propagating in the air cancel each other. Therefore, induction heating apparatus 10j according to the tenth embodiment can reduce the level of magnetic field propagation. Therefore, even if the detection operation of the object to be heated is performed in a state where the object to be heated is not placed, it is possible to prevent the surrounding electronic devices and the like from being adversely affected.

  Further, the current Ibb of the heating coil 11bb has the same current direction (phase difference = 0) as the current Iaa of the heating coil 11aa in order to reverse the currents Iba and Iab of the adjacent heating coils 11ba and 11ab.

  Here, the tenth embodiment has described the case where the adjacent heating coils 11 simultaneously perform the detection operation of the object to be heated. In addition to this, for example, in the case where the detection operation of the object to be heated is performed with an interval of two heating coils 11 as in the second embodiment shown in FIG. 8, the heating coil 11aa in the configuration shown in FIG. The direction of the detection current supplied to the heating coil 11ad is set to be reverse (phase difference = π) or substantially reverse. Thereby, the leakage magnetic field by the detection operation | movement of the to-be-heated object especially when the to-be-heated object is not mounted can be reduced.

  In the induction heating apparatus 10 in all the above embodiments, as shown in FIG. 1, the heating coils 11 in the vertical and horizontal rows are arranged so as to be in a straight line. Since the effect of the induction heating device 10 according to the disclosure can be exhibited, the configuration is not limited to this configuration.

  As described above, in the embodiment according to the present disclosure, by appropriately performing the detection operation of the object to be heated with the plurality of heating coils, it is possible to determine the placement state of the object to be heated and detect it with high accuracy. it can.

  As described above, the induction heating apparatus according to the present disclosure supplies the detection current for detecting the presence or absence of the object to be heated to the heating coil by the operation of the inverter before starting the heating of the object to be heated. The presence or absence of the heated object or the placement state can be determined. Therefore, the object to be heated can be detected without adding a new component only to detect the object to be heated, which is effective for the induction heating cooker.

DESCRIPTION OF SYMBOLS 10 Induction heating apparatus 11 Heating coil 12 Operation display part 13 Top plate 14 1st to-be-heated object (pan)
15 Second heated object (pan)
DESCRIPTION OF SYMBOLS 16 Inverter 17 Control part 18 Heated object detection part 40 Power supply 41 Diode bridge 42 Choke coil 43 Smoothing capacitor 44 1st switching element 45 2nd switching element 46 Resonance capacitor 47 Snubber capacitor 48 Current detection part 49 Voltage detection part

Claims (10)

A top plate for placing an object to be heated;
A plurality of heating coils disposed below the top plate;
An inverter for supplying a high-frequency current to the plurality of heating coils;
A control unit for controlling the output of the inverter;
An operation display unit that outputs an operation command to the control unit;
A heated object detection unit for detecting the presence or absence of the heated object placed on the top plate;
With
The control unit supplies a detection current for detecting the presence or absence of the object to be heated to the plurality of heating coils before receiving an operation command signal instructing the start of a heating operation from the operation display unit. Controlling the inverter to
The object to be heated is detected from an input current and / or output voltage in a power transmission path from a power source to the heating coil during a detection period in which the detection current is supplied to the heating coil. An induction heating device for detecting the presence or absence of
Even after the heated object detecting unit detects the heated object, the control unit is configured to perform the heating operation until the heating coil in which the heated object is detected by the operation display unit is instructed to perform the heating operation. An induction heating device that controls the inverter so as to supply the detection current to the heating coil in which the object is detected and continues the detection operation of the object to be heated by the object detection unit . Wherein the control unit, together with the sequentially supplies the detected current to the plurality of heating coils, the inverter as the heating coil is not supplied the detection current at the same time adjacent to the heating coil in which the detected current is supplied The induction heating device according to claim 1, which is controlled.   3. The induction heating apparatus according to claim 1, wherein a current value of the detection current supplied to the heating coil is smaller than a current value of a heating current supplied to the heating coil for heating the object to be heated. . The control unit controls the inverter so that the detection current is not supplied to a heating coil adjacent to a heating coil performing a heating operation, and heating that does not supply a detection current from the heating coil performing a heating operation. The induction heating device according to any one of claims 1 to 3, wherein the detection operation is continued for a heating coil disposed with the coil interposed therebetween . The plurality of heating coils have a heating coil group having at least two heating coils,
The induction heating device according to any one of claims 1 to 4 , wherein the control unit controls the inverter so as to supply the detection current to all the heating coils in the heating coil group simultaneously. After the detected object is detected by the heated object detection unit, the control unit continues the detection current to the heating coil in which the heated object is detected until the heated object is no longer detected. The induction heating apparatus according to any one of claims 1 to 5 , wherein the inverter is controlled so as to be supplied. The controller supplies the detection current to the heating coil in which the object to be heated is detected until the object to be heated is not detected after the object to be heated is detected by the object to be heated detection unit. wherein the number of times in comparison with the heating coil to be heated is not detected for controlling said inverter so as to reduce the induction heating apparatus according to any one of claims 1-6. The heated object detector is
The first threshold value used when detecting the presence or absence of the object to be heated in a state where no current is supplied to the adjacent heating coil, and the presence or absence of the object to be heated by simultaneously supplying current to the adjacent heating coil Set a second threshold to be used when detecting,
The induction heating device according to any one of claims 1, 3, and 5 to 7 , wherein the presence or absence of the object to be heated is detected using the first threshold value or the second threshold value. The heated object detector is
A first threshold value used when detecting the presence or absence of the object to be heated in a state in which no current is supplied to the adjacent heating coil, and the object to be heated while the adjacent heating coil is performing a heating operation with a minimum power. A third threshold value used when detecting the presence or absence of a heated object, and a fourth threshold value used when detecting the presence or absence of the object to be heated in a state where an adjacent heating coil is performing a heating operation with rated power And set
It said first threshold value, the third threshold value, or for detecting the presence or absence of the object to be heated using any one of the fourth threshold value, according to any one of claims 1,3,5～ 8 Induction heating device. Wherein the control unit, the detecting current supplied to the respective heating coils, to control the inverter such that the opposite between the heating coil adjacent to the vertical and horizontal direction, any one of the claims 1,5～ 9 The induction heating device according to Item.

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