JP4889535B2 - Heating equipment - Google Patents

Description

  The present invention relates to a heating device such as a cooking device using induction heating or heater heating.

  In the case of a heating device such as a heating cooker, energization of a circuit for controlling the amount of heating is normally controlled using a relay having a relay coil and a relay contact driven by the operation of the relay coil. A current flows in proportion to the amount of heating at the relay contact, and when the amount of heating is large, heat generation at the relay contact increases. Therefore, it is necessary to reduce the heat generation of the relay coil in order to reduce the heat generation of the entire relay. 2. Description of the Related Art Conventionally, a heating cooker that uses a relay drive circuit that connects a capacitor and a resistor in parallel to a relay coil and reduces the voltage applied to the relay coil in a time series, and reduces heat generation of the relay coil. It has already been proposed (see, for example, Patent Document 1). In such a heating cooker, since a large current flows through a relay that controls energization of a circuit that controls the amount of heating, a large current relay is generally used as the relay.

JP 11-224580 A

In a heating device such as a conventional cooking device, in order to keep the relay contact in the ON state, it is necessary to pass a current exceeding the holding current to the relay coil. And a large holding current flows through a resistor connected in series with the relay coil. As a result, the resistor generates a large amount of heat [resistance value × holding current ² ]. In general, since the resistance value of a resistor increases as the temperature rises, it is sufficient to use a resistor with a small change in resistance value at a high temperature so that a current equal to or higher than the holding current can flow even in a high temperature state. The vessel is large and expensive.

  The present invention has been made to solve such problems in conventional heating devices, and without using a large and expensive resistor for reducing heat generation of the relay coil, An object is to obtain a heating device capable of reducing heat generation.

Heating apparatus according to the present invention includes a first circuit for controlling the heating amount of the heating device, wherein from the commercial power input unit by opening and closing control of the relay contact has a relay contact that is opened and closed controlled by energization control of the relay coil A relay that controls power supply to the first circuit; a second circuit in which a current supplied from a DC voltage increases as the heating amount increases ; an input winding, a first output winding, and an output feedback winding; A transformer having at least a line, and a transformer control circuit that increases or decreases an applied voltage of the input winding so that a DC voltage output from the output feedback winding becomes a constant value. The transformer includes at least the input A plurality of winding layers comprising a winding, the output feedback winding, and the first output winding, wherein the winding layer comprising the first output winding comprises: It is disposed over the winding layer comprising other winding between the winding layers consisting of the output feedback winding, the first output winding, said relay coil and a DC voltage to said second circuit Is to supply.

  The transformer according to the present invention includes at least an input winding, a first output winding, and an output feedback winding. The input winding, the first output winding, and the output feedback winding are included in the transformer. There can be other aspects including a second output winding or the like, or there can naturally be an aspect including only an input winding, a first output winding, and an output feedback winding. The input winding may be divided into a plurality of winding portions and these winding portions may form different winding layers. Further, it goes without saying that other embodiments are possible without departing from the spirit of the present invention.

According to the heating device of the present invention, the first circuit that controls the heating amount of the heating device and the relay contact that is controlled to be opened and closed by energization control to the relay coil, and the commercial power supply input unit by the opening and closing control of the relay contact A relay for controlling power supply from the first to the first circuit, a second circuit in which the current supplied from the DC voltage increases as the heating amount increases, the input winding, the first output winding, and the output A transformer having at least a feedback winding, and a transformer control circuit for increasing / decreasing an applied voltage of the input winding so that a DC voltage output from the output feedback winding becomes a constant value. A plurality of winding layers including a winding, an output feedback winding, and a first output winding, and the winding layer including the first output winding includes the output layer; Is disposed over the winding layer comprising other winding between the winding layers consisting Dobakku winding, the first output winding, and supplies the DC voltage to the relay coil and a second circuit Since it did in this way, the heating apparatus which can make small heat_generation | fever of the whole relay can be obtained, without using the large-sized and expensive resistor for reducing the heat_generation | fever of a relay coil.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a heating apparatus according to Embodiment 1 of the present invention. In FIG. 1, a heating amount control circuit 3, which is a first circuit, is energized by a commercial power source from a commercial power input unit 1 via a relay 2 to control the heating amount of the heating device 4.

  The heating device according to Embodiment 1 of the present invention is a cooking device using induction heating, the heating amount control circuit 3 is constituted by an inverter circuit, and the heating device 4 is constituted by an induction heating coil. As is well known, the amount of current of the induction heating coil is controlled by on / off controlling the switching element of the inverter circuit, and the amount of heating is controlled.

  The multi-output winding transformer 8 constituting the transformer includes an input winding A, a first output winding B, a second output winding C, and an output feedback winding D. The input winding A is It is energized by the commercial power source from the commercial power input unit 1 via the transformer control circuit 10. The AC voltages induced in the first output winding B, the second output winding C, and the output feedback winding D are rectified by a diode and smoothed by a capacitor, respectively, and the DC voltages VB, VC, Output as VD.

  The DC voltage VB from the first output winding B is supplied to the fan drive circuit 6 and the relay coil 2 b of the relay 2. The relay contact 2 a of the relay 2 is on / off controlled by energization control of the relay coil 2 b by the relay coil switching element 11. The DC voltage VC from the second output winding C is supplied to the heating amount control circuit 3, and the DC voltage VD from the output feedback winding D is supplied to various control devices provided in the cooking device. It is supplied to the control circuit 7 to be controlled.

  The output feedback control circuit 9 inputs a control signal to the transformer control circuit 10 so that the DC voltage VD becomes a predetermined voltage. The transformer control circuit 10 controls the voltage to be applied to the input winding A based on the control signal from the output feedback control circuit 9, and the first output winding B, the second output winding C, and the output feedback. Predetermined DC voltages VB, VC, and VD are generated from the winding D, respectively.

  The DC voltages VB, VC, VD are voltages corresponding to the turns ratio of the respective windings B, C, D of the multi-output winding transformer 8, but generally, the input winding A and the output feedback winding D When the degree of coupling with is low, an error from a value based on the turn ratio becomes large, and the error becomes large as the degree of coupling is low. Further, when the coupling degree between the input winding A and the output feedback winding D is low, a lower voltage is generated as the load connected to each of the windings B and C is larger, and a higher voltage is obtained when the connected load is small. Will occur.

  FIG. 2 is an explanatory diagram showing the arrangement of winding layers composed of the respective windings A, B, C, and D of the multi-output winding transformer 8. In FIG. 2, the winding layer composed of the output feedback winding D is arranged on the winding layer composed of the input winding A and is set so that the degree of coupling with the input winding A is high. . The winding layer consisting of the second output winding C is disposed on the winding layer consisting of the output feedback winding D, and the winding layer consisting of the first output winding B is the second output winding. It is disposed on a winding layer made of C. From this arrangement, the first output winding B has a large distance between the input winding A and the output feedback winding D, and the degree of coupling with these windings is low. For this reason, the first output winding B has a large error in output voltage from the turn ratio due to the size of the load connected thereto.

  Here, since it is necessary to supply a stable and constant voltage to the control circuit 7, the control circuit 7 is supplied with the DC voltage VD from the output feedback winding D that becomes a predetermined voltage by feedback control. Also, since the voltage supplied to the heating amount control circuit 3 needs to be a stable and constant voltage, the heating amount control circuit 3 has a second output with a high degree of coupling between the input winding A and the output feedback winding D. The DC voltage VC from the winding C is supplied so that the output voltage error from the turn ratio is reduced.

  The feedback circuit 9 receives the DC voltage VD, which is the output voltage of the output feedback winding D, and controls the transformer control circuit 10 so that the DC voltage VD becomes a predetermined constant voltage. As a result, the DC voltage VC, which is the output from the second output winding C with high winding coupling, is also controlled to be a predetermined constant voltage.

  The DC voltage VB is supplied to the fan drive circuit 6 and the relay coil 2b. The fan drive circuit 6 performs control so that the current supplied to the cooling fan 5 that cools the inside of the device of the heating device 4 increases as the heating amount of the heating device 4 (heat generation amount of the internal components) increases.

  FIG. 3 is a graph showing the relationship between the current of the cooling fan 5 and the heating amount of the heating device 4 and the relationship between the DC voltage VB and the heating amount of the heating device 4. Since the current of the cooling fan 5 is larger than the current flowing through the relay coil 2b, the main load current of the DC voltage VB is a current for driving the cooling fan 5. As shown in FIG. 3, the DC voltage VB, which is the output of the first output winding B having a low degree of coupling between the input winding A and the output feedback winding D, increases as the current of the cooling fan 5 that is a load increases. That is, it decreases as the heating amount of the heating device 4 increases.

FIG. 4 is an explanatory diagram for explaining the amount of heat generated by the relay 2. As shown in FIG. 4, the heat generation amount P1 of the relay contact 2a and the heat generation amount P2 of the relay coil 2b are expressed by the following (formula 1) and (formula 2).
P1 = Ip ² × Rp (Formula 1)
P2 ⁼ VB 2 / Rc (Equation 2)
Here, Ip is the energization current of the relay contact 2a, Rp is the resistance of the relay contact 2a, and Rc is the resistance of the relay coil 2b.

  FIG. 5 is a graph showing the relationship between the heat generation amount P1 of the relay contact 2a with respect to the heating amount of the heating device 4, the heat generation amount P2 of the relay coil 2b, and the overall heat generation amount P of the relay 2. Since the current Ip of the relay contact 2a increases in proportion to the heating amount of the heating device 4, as shown in FIG. 4, the heat generation amount P1 of the relay contact 2a increases as the heating amount increases.

  As described above, since the voltage VB applied to the relay coil 2b decreases as the heating amount of the heating device 4 increases, the heat generation amount P2 of the relay coil 2b decreases as the heating amount increases. Therefore, when the heating amount of the heating device 4 is large, the heat generation amount P2 of the relay coil 2b automatically decreases, and the heat generation amount P (= P1 + P2) of the entire relay 2 does not increase. Further, when the heating amount of the heating device 4 is small, the energization amount to the relay contact 2a is small and the heat generation amount P1 of the relay contact 2a is small, so that the heat generation of the relay coil does not become a problem.

  Further, when the relay contact 2a is shifted from the off state to the on state, it is necessary to generate a voltage higher than the operating voltage in the relay coil 2b. Therefore, in the first embodiment of the present invention, when the relay contact 2a is shifted from the off state to the on state, that is, when the heating device starts heating, the cooling fan 5 is not energized, and the relay contact 2a shifts from the off state to the on state. Then, the heating amount control circuit 3 is energized to start heating the heating device 4, and a current is energized to the fan drive circuit 6 that drives the cooling fan 5. By performing such control, when the relay contact 2a shifts from the off state to the on state, a voltage equal to or higher than the operating voltage can be generated in the relay coil 2b.

  As described above, according to the first embodiment of the present invention, the heat generation of the relay can be reduced with a simple configuration without using a high-cost resistor that is large and has a small resistance change due to temperature.

  As a matter of course, the output of the multi-output winding transformer 8 may be applied to a heating cooker other than the heating cooker by induction heating described in the first embodiment. The output winding for supplying a voltage to the fan drive circuit 6 has a low degree of coupling between the input winding and the output feedback winding so that the flowing current increases as the heating amount increases.

  In the first embodiment, the winding configuration shown in FIG. 2 is adopted as the multi-output winding transformer. However, another winding is arranged between the output feedback winding D and the first output winding B. If it is. Such a modification of the multi-output winding transformer is shown in FIG. In FIG. 6, the input winding A is divided into a first winding portion A1 and a second winding portion A2, and the winding layer made up of the first winding portion A1 is the lowest layer. positioned. A winding layer consisting of the second output winding C is arranged on the winding layer consisting of the first winding portion A1 of the input winding A, and a winding layer consisting of the output feedback winding D is placed thereon. Is arranged. The winding layer consisting of the second winding portion A2 of the input winding A is arranged on the winding layer consisting of the output feedback winding D, and the winding layer consisting of the first output winding B is It arrange | positions on the winding layer which consists of 2 coil | winding part A2.

  According to the multi-output winding transformer shown in FIG. 6, the second of the input winding A is provided between the relay coil 2b and the first output winding B that supplies a voltage to the fan drive circuit 6 and the output feedback winding D. Since the winding portion A2 is interposed, the degree of coupling between the output feedback winding D and the first output winding B is low, and as the heating amount increases, the flowing current increases, and the same effect as described above can be achieved. it can.

Embodiment 2. FIG.
Next, a heating apparatus according to the second embodiment of the present invention will be described. In the heating cooker as the heating device according to the first embodiment, the DC voltage VB from the first output winding B is supplied to the fan drive circuit 6, but in the heating device according to the second embodiment, the DC voltage VB is supplied to the fan drive circuit 6. The voltage VB is supplied to the display circuit 12. Other configurations are the same as those of the heating cooker according to the first embodiment.

  FIG. 7 is a block diagram showing a configuration of a heating device according to Embodiment 2 of the present invention. In FIG. 2, the DC voltage VB from the first output winding B is supplied to the relay coil 2 b and the display circuit 12. Other configurations are the same as those of the first embodiment shown in FIG.

  FIG. 8 is a configuration diagram of the display circuit 12. As illustrated in FIG. 8, the display circuit 12 includes a plurality of lighting elements 13 and a display control circuit 14. The display control circuit 14 controls the number of lighting of the plurality of lighting elements 13 according to the heating amount of the heating device 4, and increases the number of lighting of the lighting elements 13 as the heating amount increases. FIG. 9 is a graph showing the relationship between the heating amount of the heating device 4 and the current flowing through the display circuit 12. Since the number of lighting elements 13 is increased as the heating amount is increased, the current flowing through the display circuit 12 is increased. Therefore, as in the case of the first embodiment, the DC voltage VB applied to the relay coil 2b decreases as the heating amount of the heating device 4 increases.

  According to the heating device according to the second embodiment described above, the heat generation of the relay can be reduced with a simple configuration without using a large-sized and low-cost resistor whose resistance value change due to temperature is small.

  As a matter of course, the output of the multi-output winding transformer 8 can also be applied to a heating cooker other than the heating cooker by induction heating described in the second embodiment, in which case the relay coil 2b and The first output winding B to be supplied to the display circuit 12 reduces the degree of coupling between the input winding A and the output feedback winding D so that the flowing current increases as the heating amount of the heating device increases. .

  Furthermore, it goes without saying that the heating device according to the present invention is not limited to a heating cooker, and can be applied to other heating devices.

It is a block diagram which shows the structure of the heating apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows arrangement | positioning of the coil | winding of the multiple output winding transformer of the heating apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between the heating amount and the electric current of a cooling fan of the heating apparatus which concerns on Embodiment 1 of this invention, and the relationship between a heating amount and DC voltage. It is explanatory drawing explaining the emitted-heat amount of the relay of the heating apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between the emitted-heat amount of the relay contact with respect to the heating amount, the emitted-heat amount of a relay coil, and the emitted-heat amount of the whole relay with respect to the heating amount which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows arrangement | positioning of the coil | winding of the modification of a multi-output winding transformer of the heating apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the heating apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the structure of the display circuit of the heating apparatus which concerns on Embodiment 2 of this invention. It is a graph which shows the relationship between the amount of heating of the heating apparatus in the heating apparatus which concerns on Embodiment 2 of this invention, and the electric current which flows into a display circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial power input part 2 Relay 2a Relay contact 2b Relay coil 3 Heating amount control circuit 4 Heating device 5 Cooling fan 6 Fan drive circuit 7 Control circuit 8 Multi-output winding transformer 9 Feedback circuit 10 Transformer control circuit 11 Relay coil switching element 12 Display circuit 13 Lighting element 14 Display control circuit A Input winding B First output winding C Second output winding D Output feedback winding

Claims (5)

A first circuit for controlling the heating amount of the heating device;
A relay that has a relay contact that is controlled to be opened and closed by energization control to the relay coil, and that controls power supply from a commercial power supply input unit to the first circuit by opening and closing control of the relay contact;
A second circuit in which the current supplied from the DC voltage increases as the heating amount increases ;
A transformer having at least an input winding, a first output winding, and an output feedback winding;
A transformer control circuit that increases or decreases the applied voltage of the input winding so that the DC voltage output from the output feedback winding becomes a constant value ;
With
The transformer includes a plurality of winding layers including at least the input winding, the output feedback winding, and the first output winding,
The winding layer consisting of the first output winding is disposed between the winding layer consisting of the output feedback winding via a winding layer consisting of another winding,
The first output winding supplies a DC voltage to the relay coil and the second circuit ;
Heating equipment characterized by that. The second circuit is a fan drive circuit that drives a fan that cools the inside of the heating device,
The fan drive circuit increases the current for driving the fan as the heating amount of the heating device increases.
2. The heating device according to claim 1, wherein The second circuit is a display circuit having a plurality of lighting elements for displaying the heating amount of the heating device,
The display circuit increases the number of lighting of the lighting elements as the heating amount of the heating device increases, and increases the current supplied to the display circuit.
2. The heating device according to claim 1, wherein The transformer includes a second output winding that supplies a DC voltage to the first circuit, and a winding layer that includes the first output winding is a winding layer that includes the output feedback winding. Disposed between the winding layers of the second output winding ,
The heating apparatus according to any one of claims 1 to 3, wherein The input winding is composed of a first winding portion and a second winding portion,
The winding layer composed of the first output winding is composed of either the first winding portion or the second winding portion between the winding layer composed of the output feedback winding. Placed through the winding layer ,
The heating apparatus according to any one of claims 1 to 3, wherein

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