JP2007265877A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of changing over the current-carrying to an internal heating coil or the internal heating coil and an external heating coil in response to the size of a pan being a heating object, of informing a user of the current-carrying state, and of carrying a current to the internal heating coil and the external heating coil regardless of the size of a pan to inform a user of the current-carrying state. <P>SOLUTION: A control part 43 controls an inverter drive part 33 to carry a high-frequency current to the internal heating coil 5a and the external heating coil 5b or only to the internal heating coil 5a according to the size of a pan, annunciates the current-carrying state through a thermal power display part 9b and a buzzer sound output part 42, forcibly makes the high-frequency current flow to the internal heating coil 5a and the external heating coil 5b regardless of the pan size when an overall heating switch 8a is depressed, and annunciates the current-carrying state through the thermal power display part 9b and the buzzer sound output part 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an induction heating cooker in which a heating coil is divided into an inner heating coil and an outer heating coil.

  A conventional induction heating cooker detects each induction heating state of an inner heating coil and an outer heating coil, an inverter circuit that allows a high-frequency current to flow through each heating coil, and a pot that is an object to be heated and each heating coil. When a small-diameter pan is induction-heated with a control device that controls the energization of the coil, the internal heating coil that is almost entirely inductively coupled to the small-diameter pan is energized, and the energization of the external heating coil with weak inductive coupling is stopped. In some cases, leakage magnetic flux is reduced, radio interference noise is suppressed, and heating efficiency is improved (see, for example, Patent Document 1).

JP 59-114789 (page 3-4, FIG. 6)

  In the above-described conventional induction heating cooker, the heating coil that is almost entirely inductively coupled to the pan is energized and the energization to the heating coil that is weakly coupled is stopped, so that it is automatically performed regardless of the user's operation. The energization heating coil switched to the pan, and the heating distribution of the pan sometimes changed without the user's knowledge. In particular, if the internal heating coil is energized for some reason, such as when the pan is temporarily moved or the pan is tilted, the internal and external heating coils will not return to the energized state, and the heating distribution is biased and the pan is heated. Unevenness became large, and sometimes the user could not cook as he wanted.

  The present invention was made in order to solve the above-described problems, and switches the energization to the inner heating coil or the inner heating coil and the outer heating coil according to the size of the pan that is the object to be heated. It is intended to obtain an induction heating cooker that informs the user of the energized state and energizes the inner heating coil and the outer heating coil regardless of the size of the pan to notify the user of the energized state. And

  The induction heating cooker according to the present invention includes a first heating coil installed on the lower surface of the top plate, a second heating coil disposed on the outer peripheral side of the first heating coil, and first and second. Discriminated by an inverter circuit for inductively heating an object to be heated on the top plate by passing a high-frequency current through the heating coil, an object to be heated determining means for determining the size of the object to be heated on the top plate, and an object determining means Energization coil selection means for allowing high-frequency current to flow only in the first and second heating coils or only the first heating coil according to the size of the heated object to be heated, and energization based on the selection of the energization coil selection means And an informing means for informing the state.

  In addition, the induction heating cooker according to the present invention includes a full surface heating switch, and the energizing coil selection means is provided in the first and second heating coils regardless of the size of the object to be heated when the full surface heating switch is operated. A high-frequency current is allowed to flow.

  In the present invention, when a high-frequency current is passed through only the first and second heating coils or only the first heating coil according to the size of the object to be heated, the energization state is notified, so that it is top for the user. The heating distribution state of the pan on the plate 3 can be grasped, and when the full surface heating switch is operated, the high frequency current flows through the first and second heating coils regardless of the size of the object to be heated. So there is an effect that you can cook as you wish.

Hereinafter, embodiments of the induction heating cooker according to the present invention will be described in detail.
Embodiment 1 FIG.
FIG. 1 is an external perspective view showing an induction heating cooker according to Embodiment 1 of the present invention.
A top plate 3 fixed by a frame 4 is provided on the top of the casing 2 of the induction heating cooker 1, and on both sides of the casing 2, resistance heating elements are arranged above and below the cooking chamber. A baked roaster 7 is provided. The above-described top plate 3 is formed of heat-resistant glass made of a non-magnetic material, and two heating coils 5 for inductively heating the pot that is the object to be heated are arranged on the front left and right sides of the lower surface of the top plate 3. A heater 6 is installed in the middle of these. As will be described later, each heating coil 5 includes a first heating coil having a small outer diameter (hereinafter referred to as “inner heating coil 5a”) and a second heating coil disposed on the outer peripheral side of the inner heating coil 5a. (Hereinafter referred to as “external heating coil 5b”).

  On the upper surface of the top plate 3, an upper surface operation unit 8 for setting the heating power of the heating coil 5 and the roaster 7 for two mouths, an upper surface display unit 9 provided in the vicinity of each heating coil 5, and a heater A display unit 10a and a heater thermal power display unit 10b are arranged. The upper surface operation unit 8 is provided with a thermal power switch for setting the thermal power of each heating coil 5 with one touch, a full surface heating switch 8a and a full surface heating LED 8b shown in FIGS. 3 (a) and 3 (b). The upper surface display unit 9 includes a liquid crystal display unit 9a and a thermal power display unit 9b for displaying the energized state and thermal power of the heating coil 5. Further, a front operation unit 11 and a front display unit 12 are provided on the front surface of the housing 2. The front operation unit 11 is provided with a power switch of the cooker 1, dials for adjusting the heating power of each heating coil 5 and the heater 6, and the front display unit 12 has a liquid crystal for the roaster 7. A display unit, a power lamp, and the like are provided.

  The above-described full surface heating switch 8a is for forcibly energizing the inner heating coil 5a and the outer heating coil 5b regardless of the size of the pan, and when energized, the energization is performed and the operation is performed again. When the power is off, turn off the power. The entire surface heating LED 8b is turned on when the inner heating coil 5a and the outer heating coil 5b are energized by the operation of the entire surface heating switch 8a, and is turned off when released. For example, as shown in FIG. 4, the thermal power display unit 9 b includes a plurality of LEDs arranged corresponding to a preset thermal power, and the inner heating coil 5 a and the outer heating coil 5 b of the heating coil 5 are energized. When the power is on, the LEDs for the set heating power are turned on as shown in FIG. 5A, and when only the inner heating coil 5a is energized, the light emission color is switched and turned on as shown in FIG. Conversely, when only the inner heating coil 5a is energized and the outer heating coil 5b is energized, the state changes from (b) to (a).

Next, the circuit of the induction heating cooker will be described with reference to FIG. FIG. 2 is a circuit configuration diagram for one heating portion showing the induction heating cooker according to the first embodiment.
The DC power supply circuit 22 includes a rectifier diode bridge 23, a reactor 24, and a smoothing capacitor 25, and converts AC power supplied from the commercial power supply 21 into DC power. The inverter circuit 28 includes two switching elements 29 and 30 connected in series between the positive and negative buses of the DC power supply circuit 22 and diodes 31 and 32 connected in antiparallel to the switching elements 29 and 30, respectively. Then, DC power is converted into high frequency power based on a switch drive signal from an inverter drive unit 33 described later. The inverter drive unit 33 turns off the switching element 30 while the switching element 29 is turned on, and turns off the switching element 29 while the switching element 30 is turned on. Is output. The snubber capacitor 34 connected to the output terminal of the inverter circuit 28 is for reducing the switching loss of the switching elements 29 and 30.

  The inner heating coil 5a of the heating coil 5 is formed by winding a coil in a ring shape and for induction heating the central portion of the pan bottom. The outer heating coil 5b is formed by winding a coil around the outer periphery of the inner heating coil 5a, and is for induction heating of a portion excluding the central portion of the pan bottom. The changeover switch 35 connected to the inner heating coil 5a is, for example, a contact of a relay (not shown), and normally the inner heating coil 5a is connected in series with the resonance capacitor 36, and when the relay driving unit 38 is activated. The internal heating coil 5 a and the external heating coil 5 b are connected to each other, and the single heating coil 5 is connected in series with the resonance capacitor 37. The temperature detector 41 detects the temperature of the pan on the top plate 3 via the inner thermistor 39 and the outer thermistor 40 arranged on the back surface of the top plate 3.

  The buzzer sound output unit 42 is a notification unit that generates a notification sound when the energization of the heating coil 5 is switched. For example, when the outer heating coil 5b is energized only when the inner heating coil 5a is energized. As shown in FIG. 5 (a), when the internal and external heating coils 5a and 5b are energized only when the energization is switched, the same sound is emitted intermittently for a predetermined time. As shown in FIG. 2B, a notification sound is emitted continuously for a predetermined time. Note that these notification sounds may be changed in pitch by changing the frequency, or may be notified by voice.

  The control unit 43 is a main member that controls the cooker 1 as a whole, and includes, for example, a microcomputer having a heated object discriminating unit and an energization coil selection unit, and controls the energization control and energization state of the inner and outer heating coils 5a and 5b. The display control to be shown will be described in detail when explaining the operation. When only the inner heating coil 5a or the inner / outer heating coils 5a and 5b are energized, the detection current of the current detection unit 26 and the detection of the voltage detection unit 27 are detected. The input power is calculated based on the voltage, and the inverter circuit 28 is controlled via the inverter drive circuit 33 so that the input power becomes the thermal power (power) set by the upper surface operation unit 8 or the front operation unit 11. .

  Next, operation | movement of the induction heating cooking appliance of Embodiment 1 is demonstrated using FIG. 6 thru | or FIG. FIG. 6 is a flowchart showing the operation of the induction heating cooker according to the first embodiment, and FIG. 7 is the positional relationship between the inner / outer heating coil and the inner / outer thermistor and the inner / outer thermistor and pan in the first embodiment. FIG. 8 is a diagram for discriminating the size of the pan from the correlation between the detected temperatures of the inner and outer thermistors in the first embodiment.

  When power is applied to the cooker 1, the control unit 43 first determines whether or not there is an instruction to start heating by turning on the dial of the front operation unit 11 (step 1). Waits here, and when an instruction to start heating is received, the relay drive unit 38 is operated to switch the connection of the changeover switch 35 to energize the inner heating coil 5a and the outer heating coil 5b. The mode is set (step 2), and the inverter drive unit 33 is controlled to start driving the inverter circuit 28 (step 3). Then, the LED of the thermal power display unit 9b is turned on according to the thermal power set by the user and the inner / outer coil mode setting (FIG. 4 (a)), and an intermittent notification sound (FIG. 5 (a)) is generated. The sound is generated from the buzzer sound output unit 42 (step 4), and the user is notified that the inner / outer coil mode is set.

  Thereafter, the input power is calculated based on the detection current of the current detection unit 26 and the detection voltage of the voltage detection unit 27, and the inverter circuit 28 is connected via the inverter drive unit 33 so that the input power becomes the set heating power. Drive (step 5). Then, it is determined whether or not the entire surface heating instruction input by the ON operation of the entire surface heating switch 8a provided in the upper surface operation unit 8 was previously performed (step 6). Since it is not at the start of heating, it is determined in step 7 whether or not there has been an entire heating instruction input by turning on the entire heating switch 8a, and if there is an input, the process proceeds to step 8, but if there is no entire heating instruction input, It is determined whether the heating flag is on or off (step 16). Since it is initially turned off, the process proceeds to step 17 to determine whether it is an internal coil mode in which only the internal heating coil 5a is energized or an internal coil mode in which the internal heating coil 5a and the external heating coil 5b are energized. do. In this case, since the inner / outer coil mode is set in step 2, the process proceeds to step 18 to enter the pan size determination.

  This determination is made based on the temperatures of the inner thermistor 39 and the outer thermistor 40 detected by the temperature detector 41. For example, as shown in FIG. 7 (a), when there is no pan on the top plate 3, the detected temperatures of the inner thermistor 39 and the outer thermistor 40 are low and become the region (a) in FIG. Is determined not to be placed. On the other hand, as shown in FIG. 7B, when a large-diameter pan is placed on the top plate 3, not only the inner peripheral portion of the pan bottom facing the inner heating coil 5a but also the outer heating coil 5b. Since the opposing pan bottom outer peripheral portion also generates heat, the detected temperatures of the inner thermistor 39 and the outer thermistor 40 are increased. In this case, in FIG. 8, the detected temperatures of the inner thermistor 39 and the outer thermistor 40 enter the region shown in FIG. Moreover, as shown in FIG.7 (c), when the small diameter pan is mounted on the top plate 3, the pot bottom which generate | occur | produces heat exists in the part facing the inner heating coil 5a, but the outer heating coil 5b Since there is no pan bottom in the portion facing the upper thermistor 39, a high temperature is detected in the inner thermistor 39, and the temperature of the pan bottom is hardly transmitted to the outer thermistor 40, resulting in a large temperature difference from the inner thermistor 39. In this case, the detected temperature of the inner thermistor 39 and the outer thermistor 40 in FIG. 8 falls within the region (c) indicated by the shaded portion, and therefore it is determined that the small-diameter pan is placed. It should be noted that not the detected temperature but the detected temperature rise degree may be used to determine that the small-diameter pan is placed when only the detected temperature rise degree of the inner thermistor 39 is large.

  When determining that the pan size is a large-diameter pan in step 18, the control unit 43 has already set the inner / outer coil mode in step 2 and proceeds to step 23, and determines that the pan size is a small-diameter pan. When this happens, the drive of the inverter circuit 28 is temporarily stopped (step 19), the changeover switch 35 is returned to the inner coil mode in which only the inner heating coil 5a is energized (step 20). Driving is resumed (step 21). Then, the emission color of the LED of the thermal power display unit 9b is switched to the inner coil mode (FIG. 4B), and a continuous notification sound (FIG. 5B) is generated from the buzzer sound output unit 42 (step) 22) Inform the user that the internal coil mode has been set.

  Thereafter, it is determined whether or not the heating power setting has been changed (step 23). If the heating power has not been changed, the process proceeds to step 26. If the heating power has been changed, the heating power display is updated by the current coil mode. That is, the number of lighting LEDs of the thermal power display unit 9b is updated according to the changed thermal power (step 24), and the changed thermal power is changed as the target power (step 25). Next, it is determined whether or not an instruction to stop heating is input (step 26). If there is an instruction to stop heating, the process proceeds to step 27, but if there is no instruction, the process returns to step 5. The operation from step 5 is repeated when there is no full surface heating instruction input (step 7) and there is no heating stop instruction input (step 26). When this operation is repeated, if the inner coil mode is selected in step 17, the process proceeds to step 23. When this operation is repeated, if a heating stop instruction is detected by turning off the dial of the front operation unit 11, the drive of the inverter circuit 28 is stopped (step 27), and the LED of the heating power display unit 9b is turned off. Thus, the heating stop state is indicated (step 28), and the process returns to the heating start instruction input waiting state (step 1).

  In addition, when the control unit 43 detects a full heating instruction input by depressing the full heating switch 8a provided in the upper surface operation unit 8 in step 7, it determines whether the full heating flag is on or off (step 8). . Since the state of the entire surface heating flag is off as described above, the flag is turned on from off (step 10), and the entire surface heating LED 8b is turned on to inform the user that the entire surface heating is to be started. Then, it is determined whether the energization coil mode is the inner / outer coil mode or the inner coil mode (step 11). When the inner / outer coil mode is selected, the process proceeds to step 23, but the inner coil mode is already set in step 20. Therefore, the process proceeds to step 12 to temporarily stop the drive of the inverter circuit 28, and the changeover switch 35 is switched to connect the inner heating coil 5a and the outer heating coil 5b to set the inner / outer coil mode (step 13). Then, the driving of the inverter circuit 28 is resumed (step 14), the emission color of the LED of the thermal power display unit 9b is switched to the inner / outer coil mode (FIG. 4 (a)), and an intermittent notification sound (FIG. 5). (A)) is generated from the buzzer sound output unit 42 (step 15), and the user is forcibly notified that the internal / external coil mode setting has been switched. Thereafter, it is determined whether or not the heating power setting has been changed (step 23). If it has not been changed, it is determined whether or not there has been a heating stop instruction input (step 26). Return to 5.

  At this time, the inverter circuit 28 is driven so that the input power becomes the set power, and it is determined whether or not the entire heating instruction has been input last time (step 6). In the previous time, since there has been an entire surface heating instruction input by pressing the entire surface heating switch 8a, the routine proceeds to step 16 where the state of the entire surface heating flag is determined. In this case, since the flag is turned on in Step 10, the process proceeds to Step 23 to determine whether or not the heating power setting has been changed. If not, it is determined whether or not a heating stop instruction has been input ( Step 26) When it is determined that there is no stop instruction input, the process returns to Step 5.

  Then, the inverter circuit 28 is driven so that the input power becomes the set power in the same manner as described above, and it is determined whether or not the previous entire surface heating instruction has been input (step 6). At this time, since there was no instruction input last time, the process proceeds to step 7 and it is determined again whether or not the entire surface heating instruction has been input by pressing the entire surface heating switch 8a. When there is no instruction input, the state of the entire surface heating flag is determined (step 16). When the on state is the same as the previous time, it is determined whether the heating power setting has been changed (step 23). It is determined whether or not there is an instruction input (step 26). If there is no instruction input, the process returns to step 5 to repeat this series of operations. By this operation, the small-diameter pan is forcibly induction-heated (entire heating) by the inner heating coil 5a and the outer heating coil 5b.

  When the small-diameter pan is forcibly induction-heated by the inner heating coil 5a and the outer heating coil 5b, if the entire heating instruction input by pressing the entire heating switch 8a is detected again in step 7, the entire heating is added and removed. To determine the state of the entire surface heating flag (step 8). In this case, since the flag is turned on in step 10 as described above, the process proceeds to step 9 to set the full surface heating flag from on to off (step 9), and the pan size determination is started (step 18). . Since the pan size is a small-diameter pan as described above, steps 19, 20, and 21 are advanced in order, switching to induction heating with only the internal heating coil 5 a, and then the LED emission color of the thermal power display unit 9 b is set to the internal color. While switching to the coil mode (FIG. 4 (b)), a continuous notification sound (FIG. 5 (b)) is generated from the buzzer sound output unit 42 (step 22), and the user is informed of the setting of the inner coil mode. Inform. Thereafter, it is determined whether or not the heating power setting has been changed (step 23). If it has not been changed, it is determined whether or not there has been a heating stop instruction input (step 26). Return to 5.

  At this time, the inverter circuit 28 is driven so that the input power becomes the set power, and it is determined whether or not the entire heating instruction has been input last time (step 6). In the previous time, since there was an input for releasing the entire surface heating by pressing the entire surface heating switch 8a, the process proceeds to step 16 to determine the state of the entire surface heating flag. In this case, since the flag is turned off in step 9, the process proceeds to step 17 to determine the energization coil mode. In this case, since the internal coil mode is set, it is determined whether or not the heating power setting has been changed in step 23. If not, it is determined whether or not a heating stop instruction has been input (step 26). If it is determined that there is no, the process returns to step 5.

  Then, similarly to the above, the inverter circuit 28 is driven so that the input power becomes the set power, and it is determined whether or not the previous entire surface heating instruction has been input (step 6). At this time, since there was no instruction input last time, the process proceeds to step 7 to determine whether or not there has been an entire heating instruction input by pressing the entire heating switch 8a. When there is no instruction input, the state of the entire surface heating flag is determined (step 16), and since it is the same off state as the previous time, the process proceeds to step 17 to determine the energized coil mode, Therefore, the process proceeds to step 23 to determine whether or not the heating power setting has been changed. If there is no change, it is determined whether or not there has been a heating stop instruction input (step 26). If there is no instruction input, the process returns to step 5 This series of operations is repeated. By this operation, the small-diameter pan is induction-heated by the inner heating coil 5a.

  As described above, according to the first embodiment, the internal / external coil mode for energizing the internal heating coil 5a and the external heating coil 5b at the start of heating is set, and the thermal power display is performed according to the set thermal power and the internal / external coil mode. The LED of the unit 9b is turned on and an intermittent notification sound is generated from the buzzer sound output unit 42. After that, when there is no full surface heating instruction input, the pan size is determined. Since the mode is switched to the inner coil mode in which only the heating coil 5a is energized, the emission color of the LED of the thermal power display unit 9b is switched to the inner coil mode, and a continuous notification sound is generated from the buzzer sound output unit 42. The user can grasp the heating distribution state of the pan on the top plate 3.

  Further, when the entire heating instruction input by pressing the entire heating switch 8a is detected in the inner coil mode in which only the inner heating coil 5a is energized, the inner heating coil 5a and the outer heating coil 5b are forcibly applied. Switch to the energized inner / outer coil mode, turn on the LED of the thermal power display unit 9b for the inner / outer coil mode, generate an intermittent notification sound from the buzzer sound output unit 42, and further heat the entire surface When it is detected that the entire heating instruction is canceled by pressing the switch 8a, the mode is returned to the inner coil mode, and the fact is notified through the LED of the thermal power display unit 9b and the buzzer sound output unit 42. There is an effect that cooking can be performed as desired because it is possible to easily confirm that the heating is being performed or to cancel the heating of the entire surface.

  In the present embodiment, the large-diameter pan and the small-diameter pan are discriminated based on the detected temperatures of the inner thermistor 39 and the outer thermistor 40 provided on the lower surface of the top plate 3. A sensor may be provided, and the size of the pan may be determined based on the detected value. Further, a light source such as an LED and an optical sensor for detecting reflected light of the light at the bottom of the pan may be provided, and the size of the pan may be determined based on the detected value.

Embodiment 2. FIG.
FIG. 9 is a circuit configuration diagram for one heating portion showing the induction heating cooker according to the second embodiment of the present invention, and FIG. 10 is a diagram showing a display pattern when the heating coil is energized. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, 2, and description is abbreviate | omitted.
The internal heating coil 5a of the heating coil 5 in the second embodiment is connected in series to the resonance capacitor 36, and the external heating coil 5b is inserted between the changeover switch 35 formed of a relay contact and the resonance capacitor 37, and the internal heating It is in parallel with the coil 5a. The resonance voltage detection unit 44 detects the voltage generated in the resonance capacitors 36 and 37 and outputs it to the control unit 43a. The controller 43a will be described in detail when explaining the operation.

  The liquid crystal display unit 9a provided on the upper surface operation unit 9 displays a double circle icon shown in FIG. 10C when the power is applied to the cooker 1, and only the inner heating coil 5a is energized. When the inner heating coil 5a and the outer heating coil 5b are energized, as shown in (b), only the inner circle is colored and displayed. When both the outer circle is colored and displayed, and the inner heating coil 5a and the outer heating coil 5b are forcibly energized (entire heating) by operating the entire heating switch 8a, the inner circle and the outer circle are displayed. (D) is displayed in a different color from (b).

Next, operation | movement of the induction heating cooking appliance of Embodiment 2 is demonstrated using FIG. FIG. 11 is a flowchart showing the operation of the induction heating cooker according to the second embodiment.
When power is applied to the cooker 1, the control unit 43a first displays a double circle icon on the liquid crystal display unit 9a provided in the upper surface operation unit 9 (FIG. 10 (c)). It is determined whether or not there is an instruction to start heating by turning on the dial of the unit 11 (step 101). If there is no instruction, it waits here, and if it receives an instruction to start heating, it sets the inner / outer coil mode to energize the inner heating coil 5a and the outer heating coil 5b (step 102), and the inverter drive unit 33 is controlled to start the drive of the inverter circuit 28 (step 103) and display the inner / outer coil mode (step 104). In this case, both the inner circle and the outer circle of the icon displayed on the liquid crystal display unit 9a are displayed with colors, and the user is informed that the inner / outer coil mode is set.

  Thereafter, the input power is calculated based on the detection current of the current detection unit 26 and the detection voltage of the voltage detection unit 27, and the inverter circuit 28 is connected via the inverter drive unit 33 so that the input power becomes the set heating power. Drive (step 105). Next, it is determined whether or not the thermal power setting has been changed (step 106). If the thermal power has not been changed, the process proceeds to step 109. If the thermal power has been changed, the thermal power display is performed according to the changed thermal power. The number of LED lighting of the unit 9b is updated (step 107), and the changed thermal power is changed as the target power (step 108). Note that the thermal power display unit 9b of the present embodiment does not change the emission color in accordance with the selection of the energizing coil mode, but simply lights up the LED corresponding to the thermal power.

  Then, it is determined whether the full surface heating flag is in an on state or an off state (step 109). Since the flag is initially off, the process proceeds to step 113, where the internal heating mode in which only the internal heating coil 5a is energized or the internal heating coil 5a. Then, the current-carrying coil mode of the inner / outer coil mode for energizing the outer heating coil 5b is determined. In this case, since the inner / outer coil mode is set in step 102, the process proceeds to step 114 to enter the pan size determination. This determination is made based on the detection current of the current detection unit 26 and the voltages of the resonance capacitors 36 and 37 detected by the resonance voltage detection unit 44. For example, when the detection current of the current detection unit 26 is large and the voltages of the resonance capacitors 36 and 37 are both high, it is determined that the pot is a large-diameter pan, and the detection current of the current detection unit 26 is smaller than the current and the resonance capacitor When the voltage of 37 is low and the voltage of the resonance capacitor 36 is higher than the voltage of the resonance capacitor 37, it is determined that the pot is a small-diameter pan.

  When determining that the pan size is a large-diameter pan in step 114, the control unit 43a determines whether or not there has been a full-surface heating instruction input by operating the full-surface heating switch 8a (step 115), and determines that there is no such instruction input. When the stop instruction input is detected (step 128), the process proceeds to step 129 when the stop instruction input is detected. When it is determined that there is no instruction input, the process returns to step 105, The inner / outer coil mode setting for energizing the inner heating coil 5a and the outer heating coil 5b is maintained.

  In step 115, when the entire heating instruction input is detected, the entire heating flag is set from OFF to ON (step 116), and the display is switched to the entire heating mode display (step 117). In this case, the display color of each of the inner and outer circles of the icon displayed on the liquid crystal display unit 9a is switched (FIG. 10D), and the user is forcibly switched to the full-surface heating. Then, similarly to the above, it is determined whether or not a heating stop instruction is input (step 128). When it is determined that there is no instruction input, the process returns to step 105 to energize the inner heating coil 5a and the outer heating coil 5b. Maintain full surface heating. In this case, since the entire surface heating flag is set to ON, step 110 is selected in step 109, and it is determined again whether or not an entire surface heating instruction has been input. If there is no instructed input, the entire surface heating is maintained. Further, when the whole surface heating is maintained, if the whole surface heating instruction input is detected in step 110, the whole surface heating flag is turned off from on (step 111), and the inner / outer coil mode display (FIG. 10B). To set the inner / outer coil mode.

  If the controller 43a determines in step 114 that the pan size is a small-diameter pan, the control unit 43a temporarily stops driving the inverter circuit 28 (step 118), turns off the changeover switch 35, and energizes only the inner heating coil 5a. The internal coil mode is set (step 119), and then the drive of the inverter circuit 28 is resumed (step 120). Then, the inner / outer coil mode display set in step 104 is switched to the inner coil mode display (step 121). In this case, only the circle inside the icon displayed on the liquid crystal display unit 9a is displayed with a color (FIG. 10A), and the user is notified that the setting has been switched to the inner coil mode setting. Thereafter, it is determined whether there has been a full surface heating instruction input by operating the full surface heating switch 8a (step 122). When it is determined that there has been no such instruction input, it is determined whether there has been a heating stop instruction input (step 128). When the stop instruction input is detected, the process proceeds to step 129. When it is determined that there is no instruction input, the process returns to step 105 to maintain the inner coil mode setting in which only the inner heating coil 5a is energized. In this case, the entire surface heating flag remains off because there is no entire surface heating instruction input. Therefore, step 113 is selected in step 109, and the process proceeds to step 122.

  If it is determined in step 122 that there is an entire heating instruction input while maintaining the inner coil mode setting, the drive of the inverter circuit 28 is temporarily stopped (step 123), and the changeover switch 35 is turned on from the off state. Then, the external heating coil 5b is set in the connected state and set to the inner / outer coil mode (step 124). Then, the full surface heating flag is set from off to on (step 125), the drive of the inverter circuit 28 is resumed (step 126), and the internal coil mode display is switched to the full surface heating mode display (step 127). In this case, the icon on the liquid crystal display unit 9a is switched from FIG. 10 (a) to FIG. 10 (d), and the inner and outer circles are displayed in different colors from FIG. Notify that the coil mode has been set. When there is no heating stop instruction input (step 128), the process returns to step 105 to maintain the forced inner / outer coil mode setting. In this case, since the entire surface heating flag is set to ON, step 110 is selected in step 109, and the forced inner / outer coil mode setting is maintained only when there is no entire surface heating instruction input.

  And when the inner / outer coil mode setting by the inner / outer coil mode display is maintained, when the compulsory inner / outer coil mode setting by the entire heating mode display is maintained, or the inner coil by the inner coil mode display If the heating stop instruction input is detected in step 128 while the mode setting is maintained, the driving of the inverter circuit 28 is stopped (step 129), and the fact that the heating is stopped is displayed on the liquid crystal display unit 9a (step 130). ), And returns to the heating start instruction input waiting state (step 101).

  As described above, in the second embodiment, the inner / outer coil mode is set at the start of heating, the inner and outer circles of the double circle icon are colored and displayed to that effect, and then the large size is determined by pan size determination. When it is determined to be a large pot, the display is maintained, and when it is determined to be a small diameter pot, it switches to the inner coil mode and only the circle inside the icon is colored to indicate that, and after determining that it is a large pot When the entire heating instruction input is detected, the entire heating flag is set to ON, and the circle inside and outside the icon is colored with a different color from the start of heating to indicate that, and the entire heating is performed after setting the inner coil mode. When an instruction input is detected, the inner / outer coil mode is forcibly set, and the entire surface heating flag is set to ON to color each circle inside and outside the icon with a different color from the start of heating. Display and whole surface When the heat flag is turned on and the entire heating instruction input is detected again, the flag is cleared and the inside and outside circles of the icon are colored in the same color as when heating is started to indicate that. Therefore, it is possible for the user to grasp the heating distribution state of the pan on the top plate 3, to easily confirm that the entire surface is forcibly heated and to cancel the entire surface heating, and cook as desired. There is an effect that can be.

  In the present embodiment, it is described that the changeover switch 35 is connected only to the outer heating coil 5b. However, in the mode in which the changeover switch 35 is also connected to the inner heating coil 5a and only the outer heating coil 5b is energized. You may make it operate. When induction heating is performed by the external heating coil 5b, only the circle outside the icon is colored and displayed to that effect.

Embodiment 3 FIG.
FIG. 12: is a circuit block diagram for 1 heating which shows the induction heating cooking appliance which concerns on Embodiment 3 of this invention. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, 2, and description is abbreviate | omitted.
Inverter circuit 28 'in the third embodiment is configured by three arms (V-phase arm 28a, W-phase arm 28b, and U-phase arm 28c) connected in series between DC buses. The V-phase arm 28a includes two switching elements 29a and 30a connected in series between the DC buses and diodes 31a and 32a connected in antiparallel to the switching elements 29a and 30a. The W-phase arm 28b It consists of two switching elements 29b, 30b connected in series between the buses and diodes 31b, 32b connected in antiparallel to the switching elements 29b, 30b, and the U-phase arm 28c is connected in series between the DC buses. It comprises two switching elements 29c, 30c and diodes 31c, 32c connected in antiparallel to each switching element 29c, 30c. Further, a full-bridge inverter that applies a high-frequency voltage to the series resonance circuit of the inner heating coil 5a and the resonance capacitor 36 is configured by the V-phase arm 28a and the U-phase arm 28c, and external heating is performed by the W-phase arm 28b and the U-phase arm 28c. A full-bridge inverter that applies a high-frequency voltage to the series resonance circuit of the coil 5b and the resonance capacitor 37 is configured.

  The inverter drive unit 33a outputs a drive signal for alternately switching on and off the switching elements 29a and 30a of the V-phase arm 28a at high frequencies, and the inverter drive unit 33b alternately switches the switching elements 29b and 30b of the W-phase arm 28b. The inverter drive unit 33c outputs a drive signal for turning on / off the switching elements 29c, 30c of the U-phase arm 28c alternately at a high frequency. These inverter drive units 33a, 33b, and 33c are performed based on control from the control unit 43b. Snubber capacitors 34a, 34b, 34c provided on the output side of each arm 28a, 28b, 28c are connected to reduce switching loss in each arm 28a, 28b, 28c. The current detector 26a is for detecting the current flowing through the inner heating coil 5a, and the current detector 26b is for detecting the current flowing through the outer heating coil 5b. The timer 45 provided in the control unit 43b is for counting the time when the entire surface is heated. The control unit 43b will be described in detail when the operation is described later.

Next, operation | movement of the induction heating cooking appliance of Embodiment 3 is demonstrated using FIG. 13 thru | or FIG. FIG. 13 is a flowchart showing the operation of the induction heating cooker according to the third embodiment, FIG. 14 is a waveform diagram of a switch drive signal for driving the switching element of each arm, and FIG. 15 is a diagram showing a pan size determination example. .
When power is applied to the cooker 1, the control unit 43b first determines whether or not there is an instruction to start heating by turning on the dial of the front operation unit 11 (step 201). Waits here and when an instruction to start heating is received, the internal / external coil mode for energizing the internal heating coil 5a and the external heating coil 5b is set (step 202), and the entire heating timer 45 is cleared. (Step 203). Next, the inverter driving units 33a, 33b, and 33c are controlled to start driving the arms 28a, 28b, and 28c of the inverter circuit 28 ′ (step 204). The drive of each arm 28a, 28b, 28c by the inverter drive units 33a, 33b, 33c is as shown in FIG. And according to the thermal power set by the user, LED of the thermal power display part 9b of the upper surface display part 9 is lighted. Note that the thermal power display unit 9b according to the present embodiment does not change the emission color according to the selection of the energization coil mode as described above, but simply lights the LED corresponding to the thermal power.

  Thereafter, the input power is calculated based on the detection current of the current detection unit 26 and the detection voltage of the voltage detection unit 27, and the input power is set via the inverter drive units 33a, 33b, and 33c so that the input power becomes the set thermal power. Then, the arms 28a, 28b, 28c of the inverter circuit 28 'are driven (step 205). Then, it is determined whether or not the entire heating timer 45 is “0” (step 206). If the timer value is not “0”, the entire heating coil 5a, 5b is forcibly energized. The timer value is decremented (step 207). When the timer value is “0”, the energization coil mode is determined (step 208). When the inner coil mode is determined, the process proceeds to step 212. However, since the inner / outer coil mode is set in step 202, the pot size is determined in step 209. The pot size is determined using the input voltage, input current, inner heating coil current, and outer heating coil current. For example, as shown in FIG. 15, the detection current of the current detector 26a (current of the inner heating coil 5a) is larger than the vertical threshold line, and the detection current of the current detector 26b (current of the outer heating coil 5b) is diagonal. When it is smaller than the threshold line, it is determined as a small-diameter pan, and the detected current of the current detector 26a (the current of the inner heating coil 5a) is larger than the vertical threshold line, and the detected current of the current detector 26b (the outer heating coil 5b). Is larger than the oblique threshold line, it is determined that the pan is a large-diameter pan. When the detection voltage (input voltage) of the voltage detector 27 is high during induction heating with the upper / lower switch drive signal of the same frequency, the vertical threshold line is on the right and the diagonal threshold line is on the upper side. Move each to increase the size. In addition, when the frequency of the upper / lower switch drive signal is increased according to the thermal power setting and the detected current (input current) of the current detector 26 is decreased, the vertical threshold line is set to the left side, and the diagonal threshold line is set to the left side. Move each down to make it smaller.

  When it is determined that the pan is large, the process proceeds to step 212. When it is determined that the pan is small, the energization coil mode is switched to the inner coil mode (step 210), and as shown in FIG. The output of the switch drive signal to 28b is stopped, and a high frequency voltage is applied only to the inner heating coil 5a. Next, a high buzzer sound (high-frequency sound) is emitted from the buzzer sound output unit 42 (step 211) to notify the user that the internal coil mode setting has been switched. Then, it is determined whether or not the thermal power setting has been changed (step 212). If the thermal power has not been changed, the process proceeds to step 218. If the thermal power has been changed, the thermal power display is made according to the changed thermal power. The number of lighting of the LED of the unit 9b is updated (step 213), and the changed thermal power is changed as the target power (step 214). Next, the energization coil mode is determined again (step 215), and if it is the inner / outer coil mode, a low buzzer sound (low frequency sound) is emitted, and it is accepted that the inner / outer coil mode is set and the set heating power is changed. (Step 216). Further, when the energization coil mode is the inner coil mode, a high buzzer sound is emitted to notify that it is the inner coil mode and that the change of the set heating power has been accepted (step 217).

  Thereafter, it is determined whether or not there is a full surface heating instruction input by turning on the full surface heating switch 8a provided in the upper surface operation unit 8 (step 218). If not, the process proceeds to step 223 to determine whether or not a heating stop instruction is input. If a stop instruction input is detected, the process proceeds to step 224. If it is determined that there is no instruction input, the process proceeds to step 205. Returning, the operation based on the determination result of the energization coil mode is repeated. When the operation is repeated in the inner / outer coil mode setting by the large-diameter pan, when the stop instruction input is detected in step 223, the output of the switch drive signal to each arm 28a, 28b, 28c is stopped and the inverter When the driving of the circuit 28 'is stopped (step 224) and the operation is repeated with the inner coil mode setting by the small diameter pan, when the stop instruction input is detected in step 223, the V-phase arm 28a and the U-phase are detected. The output of the switch drive signal to the arm 28c is stopped, and the drive of the inverter circuit 28 'is stopped (step 224). Then, a message indicating that heating is stopped is displayed on the liquid crystal display unit 9a of the upper surface display unit 9 (step 225), and the process returns to a heating start instruction input waiting state (step 201).

  When a full heating instruction input is detected in step 218, a predetermined time for energizing the internal / external heating coils regardless of the pan size is set in the full heating timer 45 (step 219), and the energizing coil mode is set. Is determined (step 220). If the inner / outer coil mode is selected, the process proceeds to step 223. If the inner coil mode is determined, the inner / outer coil mode is set again (step 221), and the output of the switch drive signal to the W-phase arm 28b is resumed. (FIG. 15A), a high frequency voltage is applied to the inner heating coil 5a and the outer heating coil 5b. Then, a low buzzer sound (low frequency sound) is emitted from the buzzer sound output unit 42 (step 222) to notify that the inner / outer coil mode is set.

  Thereafter, similarly to the above, it is determined whether or not a heating stop instruction is input (step 223). When a stop instruction input is detected, the process proceeds to step 224. When it is determined that there is no instruction input, step 205 is performed. The operation is repeated until the predetermined time of the timer 4 reaches “0”. After that time becomes “0”, the operation is based on the result of determining the pan size. When the heating stop instruction input is detected, the output of the switch drive signal to each arm 28a, 28b, 28c is stopped. Then, the drive of the inverter circuit 28 'is stopped (step 224), the fact that the heating is stopped is displayed on the liquid crystal display portion 9a of the upper surface display portion 9 (step 225), and the state returns to the state of waiting for the instruction to start heating (step 201). ).

  As described above, according to the third embodiment, the user determines whether the heating coil 5 energized by the notification sound is in the state of only the inner heating coil 5a or the state in which both the inner heating coil 5a and the outer heating coil 5b are energized. Since it can be known, it is possible to grasp the heating distribution of the pan without any special additional display means. In addition, even when only the inner heating coil 5a is energized against the user's intention, the inner / outer coil mode in which the inner heating coil 5a and the outer heating coil 5b are energized for a predetermined time by inputting the entire surface heating instruction. After a predetermined time has elapsed, it returns to the energized coil mode according to the pan size, so heating efficiency is good even for small-diameter pans, reducing leakage magnetic flux, and cooking as desired by the user Is possible.

  Further, it is possible to switch between the inner / outer coil mode for energizing the inner heating coil 5a and the outer heating coil 5b and the inner coil mode for energizing only the inner heating coil 5a without stopping the drive of the inverter circuit 28 '. Smooth cooking operation is possible.

  In the above-described three embodiments, a mode in which the energization state of the inner heating coil 5a and the outer heating coil 5b is notified by display and sound, a mode in which only the display is informed, and a mode in which only the sound is notified are shown. However, in any of the embodiments, the notification means in the other embodiments may be used.

  Moreover, although the operation example which switches the internal / external coil mode which supplies electricity to the internal heating coil 5a and the external heating coil 5b, and the internal coil mode which supplies electricity only to the internal heating coil 5a was shown, the mode which supplies electricity only to the external heating coil 5b May be provided for notification.

It is an external appearance perspective view which shows the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows 1 heating part of the induction heating cooking appliance which concerns on Embodiment 1. FIG. FIG. 3 is a diagram showing a full surface heating switch and a full surface heating display LED in the first embodiment. FIG. 3 is a diagram illustrating an example of a thermal power display at the time of switching energization of the inner and outer heating coils in the first embodiment. FIG. 6 is a waveform diagram showing an example of a buzzer sound when energization switching of the inner and outer heating coils in the first embodiment is performed. It is a flowchart which shows operation | movement of the induction heating cooking appliance which concerns on Embodiment 1. FIG. FIG. 3 is a side arrangement diagram showing the positional relationship between the inner / outer heating coil and the inner / outer thermistor and the positional relationship between the inner / outer thermistor and the pan in the first embodiment. FIG. 3 is a diagram for discriminating the outer diameter of the pan from the correlation between the detected temperatures of the inner and outer thermistors in the first embodiment. It is a circuit block diagram for 1 heating which shows the induction heating cooking appliance which concerns on Embodiment 2 of this invention. It is a figure which shows the display pattern at the time of electricity supply of a heating coil. It is a flowchart which shows operation | movement of the induction heating cooking appliance which concerns on Embodiment 2. FIG. It is a circuit block diagram for 1 heating which shows the induction heating cooking appliance which concerns on Embodiment 3 of this invention. It is a flowchart which shows operation | movement of the induction heating cooking appliance which concerns on Embodiment 3. It is a wave form diagram of the switch drive signal which drives the switching element of each arm. It is a figure which shows the example of determination of pan size.

Explanation of symbols

5 heating coil, 5a inner heating coil, 5b outer heating coil, 8 upper surface operation unit, 8a full surface heating switch, 8b full surface heating LED, 9 upper surface display unit, 9a liquid crystal display unit, 9b thermal power display unit, 11 front operation unit, 28 28 'inverter circuit, 33 inverter drive unit, 35 selector switch, 36, 37 resonance capacitor, 38 relay drive unit, 39 internal thermistor, 40 external thermistor, 41 temperature detection unit, 42 buzzer sound output unit, 43, 43a, 43b Control unit, 44 resonance voltage detection unit, 45 timer.

Claims (3)

A first heating coil installed on the lower surface of the top plate;
A second heating coil disposed on the outer peripheral side of the first heating coil;
An inverter circuit that applies a high-frequency current to the first and second heating coils to inductively heat an object to be heated on the top plate;
Heated object discriminating means for discriminating the size of the heated object on the top plate;
Energizing coil selection means for allowing a high-frequency current to flow only in the first and second heating coils or only the first heating coil in accordance with the size of the object to be heated determined by the object to be heated determining means;
An induction heating cooker comprising: an informing means for informing an energized state based on selection of the energizing coil selecting means. It has a full surface heating switch,
2. The energizing coil selection means is configured to cause a high-frequency current to flow through the first and second heating coils regardless of the size of an object to be heated when a full surface heating switch is operated. Induction heating cooker. 3. The induction heating according to claim 2, wherein when the full surface heating switch is operated, the notifying unit notifies that the first and second heating coils are forcibly energized. 4. Cooking device.

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