JPH0612700B2 - Multi Induction Cooker - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multi-port induction heating cooker.

2. Description of the Related Art An induction heating cooker emits a high-frequency alternating magnetic field from a heating coil located below a heating port (hereinafter referred to as a burner) to induce an electric current in the bottom of an iron or stainless steel pot placed on the burner. , It is a heating device that heats the bottom of the pot to cook, and the rated power consumption per burner has conventionally been between 0.5 KW and 3 KW. The multi-port induction heating cooker is a cooker configured by arranging a plurality of the above-mentioned burners. For example, there is a 4-burner induction heating cooker in which two 1.2 kW and two 2.5 kW are arranged.

Therefore, in the multi-port induction heating cooker, the total power consumption increases when a plurality of burners are operated simultaneously.
In the case of the above-mentioned four burner, the total power consumption is 7.4 KW, and when the power supply voltage is 100 V, the current flowing through the distribution line is 74 A, which is an extremely large current. Even when operating a single burner, when the 2.5 KW burner is operated, the input current is the same when the power supply voltage is 100 V.
If so, it becomes 25 A, and a large current also flows. When examining the current capacity of household outlets, fuses, breakers, etc., which are currently used in ordinary households, many of them are about 15A. Therefore, when the multi-port induction heating cooker is connected to a household outlet and operated, an overcurrent may flow and the fuse of the power supply may blow.

Problems to be Solved by the Invention The induction heating cooker is not as well known to the user as other nichrome wire type or sheath heaters, and the phenomenon that the cooking can be done without an open flame or a red-heated heater or In order to let the user clearly understand the heating principle, cooking method, etc., it is necessary to actually operate them in front of them for demonstration. However, as mentioned above, it exceeds the input current of the multi-port induction heating cooker. Distribution lines are often not laid in general households or showrooms, and if the user mistakenly operates a burner with a large amount of power, problems may occur. It was difficult to get people to know more about the cooker by operating with.

Therefore, in view of the drawbacks of the above-mentioned multi-port induction heating cooker, the present invention teaches a user who has no product knowledge while operating the multi-port induction heating cooker by using the outlet of a showroom or a general household. It was made possible.

Means for Solving the Problems Technical means of the present invention for solving the above problems are a multi-port induction heating cooker, a connection terminal to a three-wire commercial power supply, and a power supply voltage detection circuit for detecting the input power supply voltage. The power supply voltage detection circuit outputs an inhibition signal to the switching element on / off control circuit that controls oscillation of an inverter circuit including a specific heating coil, a resonance capacitor, and a switching element when the power supply voltage is equal to or lower than a predetermined voltage. However, the energization of a specific heating coil is prohibited.

Action The action of this technical means is as follows.

That is, when the multi-port induction heating cooker is normally connected to the three-wire type commercial power source, all heating coils can be energized and cooking can be performed as specified, as in the conventional case.

However, when a two-wire power outlet for a showroom or a general household is used as a power source for the multi-port induction heating cooker, one of the three input terminals of the cooker is not connected. At this time, in the present invention, since the detection circuit for detecting the inter-terminal voltage of the input terminal is provided, the voltage detection circuit for detecting the voltage between the terminals to which no voltage is applied is An inhibition signal is output to the control circuit, and based on this signal, the control circuit drives only the inverter circuit including the specific heating coil connected to the terminal to which the voltage is applied.

As a result, when a multi-port induction heating cooker is actually operated using a general household two-wire outlet, only a specific heating coil can be energized. Therefore, the output power of the inverter circuit including the specific heating coil does not exceed the power capacity of a general household outlet or distribution line, for example, 1.
If the power is set to about 3 kW, even if the user mistakenly tries to operate to energize the plurality of heating coils, the power supply voltage is 1
In the case of 00V, there is no fear that a current of 13A or more will flow to the distribution line, and there will be no trouble that the fuse or breaker of the distribution board blows.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.
In FIG. 1, the first power supply 1 and the second power supply 2 are three-wire commercial power supplies in which one wire is common at the connection points. The first power supply 1 is rectified by the rectifier 3, and the DC power supply voltage is supplied to the high frequency inverter circuits A and B. The second power supply 2 is rectified by the rectifier 4, and the DC power supply voltage is also supplied to the high frequency inverter circuits C and D. The structure of the high frequency inverter circuit A is as follows. That is, one side terminal of the filter coil 5a is connected to the positive output terminal of the rectifier 3, and the parallel circuit of the resonance capacitor 8a and the heating coil 7a is a switching transistor (hereinafter simply referred to as switching transistor) 9a in which a diode is connected in antiparallel. Is connected in series with the filter capacitor 6a and is connected between the other terminal of the filter coil 5a and the negative output terminal of the rectifier 3. The configurations of the high-frequency inverter circuits B, C, and D are the same as those of the high-frequency inverter circuit A, and the corresponding numbers are shown with supplementary numbers (b, c, d). Control circuit 10
a, 10b, 10c, 10d output terminals d, d ', e,
e ', f, f', g and g'are respectively connected between the base and emitter of the switching transistors 9a, 9b, 9c and 9d.

Next, the input terminals j and j'of the power supply voltage detection circuit 11 are connected to the terminals a and b of the first commercial power supply 1 and the output terminals l and l '.
Is connected to the input terminals i and i'of the control circuit 10d of the high frequency inverter circuit D, and the input terminals k and k'of the power supply voltage detection circuit 11 'are connected to the terminals b and c of the second commercial power supply 2. The output terminals m and m'are connected to the input terminals h and h'of the control circuit 10b of the high frequency inverter circuit B.

The configuration of the power supply voltage detection circuit 11 will be described in more detail. Resistors 101 and 102 connected in series to the input terminals j and j '
The anode of the diode 103 is connected to the connection point of, and the parallel circuit of the capacitor 104 and the resistor 105 is connected between the cathode of the diode 103 and the other end of the resistor 102, that is, the terminal j ′. The diode of the photocoupler 106 is connected in parallel to both ends of the resistor 105. The collector and emitter of the photocoupler 106 are connected to the output terminals 1 and 1 ', respectively. Power supply voltage detection circuit 11 '
The configuration is the same as that of the power supply voltage detection circuit 11, and parts corresponding to the power supply voltage detection circuit 11 are denoted by the same reference numerals.

Further, in the induction heating cooker of the present embodiment, the heating coil 7a and the heating coil 7c are heating coils for a small output (1.2 KW each), and the heating coil 7b and the heating coil 7d are heating for a large output (2.2 KW each). The high frequency inverter circuits A, B, C and D, which are coils, are also designed according to the output of each heating coil.

Next, the operation of the first embodiment will be described. High frequency inverter circuit A and other high frequency inverter circuits B, C,
Since the circuit configuration of D is the same, the high frequency inverter circuit A
The operation will be described as a representative. When the commercial power supply 1 is applied to the rectifier 3, it is rectified and the filter coil 5a
A DC voltage is applied across the filter capacitor 6a via the. The switching transistor 9a has a base,
The output terminal d of the control circuit 10a connected between the emitters,
It is turned on and off by the drive pulse from d '. Filter condenser 6a and heating coil 7
Since a parallel circuit of a and the resonance capacitor 8a and a series closed circuit of the switching transistor 9a form a resonance circuit, a high-frequency large current of about 25 kHz is generated in the heating coil 7a by turning on and off the switching transistor 9a, and heating. The coil 7a (having a flat plate shape) generates a high frequency magnetic field. Therefore, since the high-frequency magnetic field passes through the load pan bottom placed near the heating coil 7a, an electric current is induced in the pan bottom, and the pan bottom is heated by Joule heat. As described above, when the first power supply 1 and the second power supply 2 are normally applied, all four heating coils 7a, 7b, 7c, 7d are in a state capable of being energized (heated). ing.

Next, the operation when only the first power supply 1 is applied and the second power supply 2 is not applied will be described.

In this case, a DC voltage is applied to the high frequency inverter circuits C and D,
Since it is not supplied from the output end of the rectifier 4, the heating coil 7c
And 7d is in a state where it cannot be energized.

Further, the terminals b and c of the second power supply 2 are connected to the voltage detection circuit 1
Since the input terminals k and k'of 1'are connected, no voltage is applied to k and k'in this case. Therefore, no current flows through the diode of the photocoupler 106 ', and the output terminals m and m'are opened. The output terminals m and m'are connected to the input terminals h and h'of the control circuit 10b of the high frequency inverter circuit B. When the input terminals h and h'are opened, the control circuit 10b operates the high frequency inverter circuit B. Is configured to ban. Therefore, in this case, the heating coil 7b cannot be energized. As a result, when the second power source 2 is not applied to the multi-port induction heating cooker of this embodiment and only the first power source 1 is applied, only the heating coil 7a for the small outlet (1.2 KW) can be energized. Becomes
Similarly, when only the second power source is used, only the heating coil 7c for small output (1.2 KW) can be energized.

Next, a second embodiment of the present invention will be described. FIG. 2 shows a second embodiment, which is a multi-port induction heating cooker having four heating coils. In the first embodiment, the first power source is the power source applied to the inverter for energizing the small mouth heating coil and the inverter for energizing the large mouth heating coil, and the second power source is the energization of the other two heating coils. In the second embodiment, as shown in FIG. 2, the high frequency inverter circuit 14a is connected from both ends a and c of the series connection of the first power source 1 and the second power source 2 as shown in FIG. , 14
b, 14c and 14d are used as power sources and input through the rectifiers 12 and 13. When the first power supply 1 and the power supply 2 have the same phase, the voltage between the terminals a and c is the sum of the first power supply 1 and the second power supply 2, and when the first and second power supply voltages are 100V,
The voltage between the terminals a and c is 200V.

In addition, the power supply voltage detection circuit includes a first power supply 1 and a second power supply 2.
Connected between the connection terminal b of the second power supply 2 and the other terminal c of the second power supply 2, and the output signal of the voltage detection circuit 16 is the control circuit 15
When the voltage from the second power supply 2 is not applied to the voltage detection circuit 16, the voltage detection circuit 16 outputs an inhibit signal to the control circuits 15b, 15c and 15d.
15c, 15d to output the high frequency inverter circuit 14
The operation of b, 14c and 14d is prohibited and only the heating coil 14a belonging to the high frequency inverter circuit 14a can be operated. In the second embodiment, only 14a is a high-frequency inverter circuit with a small output (1.2 KW) rating, and the other high-frequency inverter circuits 14b, 14c, 14d are high-power circuits with an output rating of 2.5 KW. The operation of the second embodiment will be described. The four-port electromagnetic cooker of the second embodiment can be operated by connecting a commercial power source of 200V to the input terminal. However, as described above, if the voltage of 100V is not applied to the voltage detection circuit 16, Only the high frequency inverter circuit 14a operates. Therefore, as shown in FIG. 3, the voltage of the terminals a and b of the first power source 1 is boosted to 200 V by the step-up transformer 17, and the terminals j and j'to which the voltage is applied have the four ports of the second embodiment. Even if the input terminal of the induction heating cooker is connected, no voltage is applied to the voltage detection circuit 16, so that only the high frequency inverter circuit 14a operates.

EFFECTS OF THE INVENTION The present invention provides a connecting means for inputting a three-wire type commercial power source including a first power source and a second power source having a single wire as a common line, and a voltage between two predetermined terminals of the three-wire commercial power source. Is provided with a power supply voltage detection circuit for detecting a voltage, and when the voltage between two predetermined terminals is below a predetermined level, energization is prohibited except for a specific heating coil of the multi-port induction heating cooker. Therefore, if the output power of the heating coil that can be energized is set to be equal to or less than the current capacity of the distribution board of a general household (for example, 1500 W (15 A) for a power supply voltage of 100 V), the three-wire system If you use a household two-wire outlet without using a commercial power supply, it will automatically output another large output (for example, 2.5 kW (25 V at 100 V power supply voltage).
Since it is prohibited to operate the heating coil in A)) or to operate multiple heating coils at the same time, there is no risk of exceeding the capacity of the distribution line at home and blowing fuses or breakers on the distribution board. Even in areas where the power supply situation is poor, there is no need to newly install a dedicated power supply line, and a customer, user, or This has the effect of explaining the usage method, principle, effects, etc. of the induction heating cooker to visitors in the showroom in peace. In addition, if the output signal of the voltage detection circuit is prohibited only the operation of the inverter circuit and the power setting display and the power lamp display of the operation part of the multi-port induction heating cooker can operate normally, It is possible to demonstrate a more effective multi-mouth induction cooker without sacrificing unnaturalness when explaining it at home and at home.

[Brief description of drawings]

1 is a circuit diagram of a multi-port induction heating cooker according to an embodiment of the present invention, FIG. 2 is a circuit block diagram of a multi-port induction heating cooker according to another embodiment of the present invention, and FIG. 3 is a power supply voltage. It is a circuit diagram of a step-up transformer that doubles. 1 ... 1st power supply, 2 ... 2nd power supply, 7a, 7b, 7
c, 7d ... heating coil, 8a, 8b, 8c, 8d ...
Resonant capacitors, 9a, 9b, 9c, 9d ... Switching transistors, 10a, 10b, 10c, 10d ...
... Control circuit, 11, 11 '... Voltage detection circuit.

Claims (1)

[Claims] 1. A connection terminal to a three-wire commercial power source, a plurality of inverter circuits including a heating coil, a resonant capacitor, and a switching element, a control circuit for controlling on / off of the switching element, and a three-wire commercial power source. A power supply voltage detection circuit for detecting a voltage between two predetermined terminals of the connection terminal, wherein the power supply voltage detection circuit sends an inhibition signal to the control circuit when the voltage between the predetermined two terminals is equal to or lower than a reference level. Multi-port induction heating cooker that outputs and prohibits energization of a specific heating coil.