JPH0574567A - Combined cooker - Google Patents

Abstract

(57) [Summary] [Configuration] The control circuit 15 is configured to control the resistance heating element 4 via the duty ratio control circuit 3 and control the electromagnetic induction heating section 7 via the oscillation control circuit 17. When performing a soft start process that gradually increases the energization rate with respect to the power supply cycle at the start of energization to the, the power supply to the electromagnetic induction heating unit 7 in use is temporarily stopped, and the soft heating process to the resistance heating element 4 After the above, the power supply to the electromagnetic induction heating unit 7 is started again. [Effect] The effect of preventing the abnormal noise of the electromagnetic induction heating unit caused by the voltage drop of the AC power supply generated at the start of energization of the resistance heating element having a large inrush current such as a halogen heater is great.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite heating cooker in which a heating means having a resistance heating element and a heating means by an electromagnetic induction heating section are incorporated in one box.

[0002]

2. Description of the Related Art A composite heating cooker in which a heating means having a resistance heating element and a heating means by an electromagnetic induction heating section are incorporated in one box is disclosed in Japanese Utility Model Publication Nos. 55-124796 and 61-83299. It is proposed in the bulletin. These assumed a sheathed heater or a nichrome heater as the resistance heating element.

[0003]

Recently, a cooker using a halogen heater as a heating means has been developed. Halogen heaters have the advantage of being instantly heatable and highly recognizable of the heat generated by the heat generated. Also, since a large inrush current flows through the halogen heater at the start of energization (10% of the rated current).
It is common to perform a so-called soft start process that gradually increases the energization rate, but a voltage drop on the power supply line is unavoidable.

This is a cause of an annoying noise due to a pan or the like in a composite heating cooker in which a halogen heater and electromagnetic induction heating are incorporated in the same box, because the current and voltage waveforms of the electromagnetic induction heating section are disturbed. ..

[0005]

The present invention has been made to solve the above-mentioned problems, and one or more,
That is, in a combined heating cooker in which a heating means having an appropriate number of resistance heating elements, a heating means by an electromagnetic induction heating section, and a control circuit for controlling these heating means are incorporated in one box, the control circuit has a duty ratio. A soft start in which the resistance heating element is controlled via the control circuit and the electromagnetic induction heating section is controlled via the oscillation control circuit, and the energization rate is gradually increased with respect to the power supply cycle when the energization of the resistance heating element is started. When performing the treatment, the energization to the electromagnetic induction heating unit in use is temporarily stopped, and after the soft start treatment to the resistance heating element is finished, the energization to the electromagnetic induction heating unit is started again.

[0006]

With the above configuration, the power supply to the resistance heating element is stabilized and the fluctuation of the power supply voltage is eliminated while the power supply to the resistance heating element is stopped during the soft start process when the resistance heating element is energized. From the above, the electromagnetic induction heating unit is started to be energized again to eliminate the abnormal noise generated by the power supply voltage fluctuation in the electromagnetic induction heating unit.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram of essential parts of a composite heating cooker according to an embodiment of the present invention. FIG. 2 is a timing chart of control signal waveforms.

In FIG. 1, an AC power source 1 is connected via a switch 2 to a duty ratio control circuit 3 and a resistance heating element portion 5 composed of a resistance heating element 4 which is a heating means by resistance heating such as a halogen heater. It is connected via a current fuse 6 to an electromagnetic induction heating section 7 which is a heating means by electromagnetic induction heating. The electromagnetic induction heating unit 7 converts the AC power source 1 into a direct current by the rectifying stack 8, and the choke coil 9 and the smoothing capacitor 10
Smoothed by a smoothing circuit configured by and connected to the resonance circuit composed of the heating coil 11 and the resonance capacitor 12, and an anti-parallel diode 13 and switching element 14 are connected in parallel to form an inverter circuit. ..

The control circuit 15 receives inputs from the input device 16 such as ON / OFF of the resistance heating element 5 and the electromagnetic induction heating section 7 and setting of heating power, and the duty ratio control circuits 3 of appropriate number of resistance heating elements 4 and 3. The oscillation control circuit 17 for the electromagnetic induction heating unit 7 is controlled.
The oscillation control circuit 17 is an inverter circuit, that is, a circuit that controls the duty ratio and ON / OFF of the switching element 14. Next, the operation of this embodiment having the above configuration will be described.

In FIG. 2, the input waveform of the AC power supply 1, the duty ratio control pulse of the resistance heating element 4 by the duty ratio control circuit 3, and the oscillation control signal of the electromagnetic induction heating unit 7 by the oscillation control circuit 17 are shown from the top. This example is a case where energization of the resistance heating element portion 5 is started while the electromagnetic induction heating portion 7 is in use.

Section A is a waveform in which only electromagnetic induction heating is in operation. In this case, the oscillation control signal is in the oscillation enable state. When the energization of the resistance heating element 4 is permitted by the user's key input from the input device 16, in the section B, the soft start processing to the resistance heating element 4 is performed. The soft start process gradually increases the duty ratio with respect to the waveform of the AC power source to prevent the rush current to the resistance heating element 4.

In this example, the duty ratio is controlled for five half-waves of the AC power supply waveform, and the continuous conduction state starts from the sixth wave. In the section in which the soft start process is performed, the oscillation control signal is stopped and the electromagnetic induction heating unit 7 is stopped from being energized.

After the resistance heating element 4 is continuously energized in the section C, the oscillation control signal is set to the oscillation permission state. The switching of the oscillation control signal may be performed immediately after entering the section C or after a certain period of time.

Since a normal soft start process takes about 1 second at the longest, cooking is not affected even if the electromagnetic induction heating section 7 is de-energized during that time.

Even when there are a plurality of heating means by the resistance heating element 4 having a large inrush current, such as a halogen heater, the same processing is performed when performing soft start processing on any one of the resistance heating elements 4. ..

[0016]

According to the present invention, a heating means having one or a plurality of resistance heating elements, that is, an appropriate number of resistance heating elements, a heating means by an electromagnetic induction heating section, and a control circuit for controlling these heating means are provided. In the compound cooker built into the box, the control circuit is configured to control the resistance heating element via the duty ratio control circuit and control the electromagnetic induction heating section via the oscillation control circuit. If you do
Since it is assumed that the electromagnetic induction heating part in use is temporarily de-energized, the soft heating process for the resistance heating element is completed, and then the electromagnetic induction heating part is de-energized again. The large effect of preventing abnormal noise of the electromagnetic induction heating unit caused by the voltage drop of the AC power supply generated at the start of energization of the large resistance heating element is large.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an essential part of a composite heating cooker showing an embodiment of the present invention.

FIG. 2 is a timing chart of control signal waveforms.

[Explanation of symbols]

 3 Duty factor control circuit 4 Resistance heating element 7 Electromagnetic induction heating part 15 Control circuit 17 Oscillation control circuit

Claims (1)

[Claims] 1. A heating means having an appropriate number of resistance heating elements (4), a heating means by an electromagnetic induction heating section (7), and a control circuit (15) for controlling these heating means in one box. In the built-in combined cooker, the control circuit (15) controls the resistance heating element (4) through the duty ratio control circuit (3) to control the oscillation control circuit.
The electromagnetic induction heating unit (7) is controlled via (17),
When performing a soft start process that gradually increases the energization rate with respect to the power supply cycle at the start of energization of the resistance heating element (4),
It is assumed that the current supply to the electromagnetic induction heating part (7) is once stopped, and after the soft start process to the resistance heating element (4) is finished, the power supply to the electromagnetic induction heating part (7) is started again. A composite heating cooker characterized by the above.