JPH05190258A - Heat cooking device - Google Patents

Abstract

PURPOSE:To low suppress generation of a noise by decreasing a voltage drop of an AC power supply generated at phase control time, and preventing unbalance of life of a heating unit. CONSTITUTION:A heat cooking device in which a plurality of heating units 2a, 2b are provided in a heating unit 2 and divided into two groups to provide phase control circuits 3a, 3b in each group unit, and a control circuit 6 outputs an electrification control pattern for the phase control circuit 3a in the one group and an electrification control pattern for the phase control circuit 3b in the other group switched at each fixed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker with an improved control method for heating elements.

[0002]

2. Description of the Related Art The number of heating cookers using sheathed heaters or halogen heaters as heating sources in place of gas stoves is increasing in terms of safety, cleanliness and usability. Among them, the heating cooker that uses a halogen heater as a heating source,
Since the degree of light emission changes depending on the immediate heat and the heat power, it can be used like a casrange. The heating unit of this cooker has 2 to 4 halogen heaters connected in parallel,
The heating power was adjusted by changing the duty ratio by phase control.

[0003]

Recently, a heating 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. However, since the inrush current of the halogen heater flows several times more than the rated current (about 10 times the rated current), the voltage drop of the AC power supply line may occur at the start of energization or phase control. It may have adversely affected other equipment being used.

For example, noise invades telephones and audio equipment, and further, in a composite heating cooker in which a halogen heater and electromagnetic induction heating are incorporated in the same box, the input voltage waveform of the electromagnetic induction heating section rushes in. Disturbance due to the voltage drop due to the current and shaking of the heating coil current sometimes caused an annoying noise from the pot.

Therefore, in that case, a large filter circuit had to be inserted in the power supply line of the device to prevent it.

[0006]

The present invention has been made to solve the above-mentioned problems, and in a heating cooker having an appropriate number of heating units and having phase control means for these heating units, Having a plurality of heating elements in the heating unit, dividing these heating elements into two groups, each group unit is provided with a phase control circuit, the control circuit is a conduction control pattern of the phase control circuit of one group, It is assumed that the energization control patterns of the phase control circuits of the other group are switched at regular intervals.

[0007]

With the above configuration, for example, when setting a low heating power, the heating of one of the two heating bodies is stopped, the remaining heating bodies are phase-controlled, and When setting to thermal power, energize one heating body continuously and perform phase control on the remaining heating bodies, and switch the energization control pattern in each case at fixed intervals to perform all heating. The voltage drop due to inrush current is reduced compared to the case where the body is controlled in phase at the same time.
In addition, since the energization time of each heating element group is almost the same, it has an effect of preventing imbalance in the life of the heating elements.

[0008]

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 a main part of a heating cooker according to an embodiment of the present invention, FIG. 2 is an example of heating power setting of the heating unit, and FIG. 3 is a timing chart of the control signal waveform.

In FIG. 1, heating elements (heaters such as a halogen heater or a sheath heater in this embodiment) 2a and 2b are connected to an AC power source 1 via phase control circuits 3a and 3b, respectively. The heating unit 4 is connected via the phase control circuit 5. The heating elements 2 a and 2 b are arranged in the same heating unit 2, and the heating elements are also arranged in the separate heating unit 4. The control circuit 6 controls energization of the heating units 2 and 4 by input from an input device (not shown). The control circuit 6 outputs energization control pulses to the phase control circuits 3a, 3b and 5.

Next, the operation of this embodiment having the above structure will be described.

In FIG. 2 showing an example of setting the energization of the heating elements 2a and 2b with respect to the heating power setting of the heating unit 2, in the case of the heating power setting A, the setting is equal to or less than the maximum power of one heating element group, and in the case of the heating power setting B, it is one. The setting is set to exceed the maximum electric power of one heating element group and less than the total electric power supplied. In the case of the thermal power setting C, the total electric power supplied is set to the maximum.

FIG. 3 shows an example of the phase control pulses P3a and P3b which the control circuit 6 outputs to the phase control circuits 3a and 3b in the case of each thermal power setting in FIG. The waveform V is the voltage waveform of the AC power supply 1, and the switching cycle of the energization control pattern is one cycle. In the thermal power setting A, the phase control pulse of either P3a or P3b is output. In the thermal power setting B, a pulse is output to the zero-cross point of the AC power supply 1 for either P3a or P3b for continuous energization, and the other outputs a phase control pulse. In heat setting C, P3a, P3b
In both cases, a pulse is output to the zero-cross point of the AC power source 1 to continuously energize both heating bodies 2a and 2b.

Although the switching cycle is one power cycle in the above embodiment, it is obvious that the same effect can be obtained if the switching control is performed at least every half cycle. Regardless of these controls for the heating unit 2, the control circuit 6 outputs an energization control pulse to the phase control circuit 5 to control the energization of the separate heating unit 4.

As shown in FIG. 4, the voltage drop due to the inrush current is reduced in the waveform of the above-described embodiment, in contrast to the waveform in the conventional control method of the voltage waveform of the AC power supply 1. .

[0015]

According to the present invention, a plurality of heating elements in one heating unit are divided into two groups, and the energization control pattern is switched at regular intervals for each group to perform phase control. Therefore, the phase control is performed for one of the groups, and the other group is controlled such as energization stop or continuous energization, and by switching the energization control pattern at regular intervals, the AC power supply generated during the phase control is controlled. It is possible to reduce the voltage drop, prevent imbalance in the life of the heating element, reduce distortion of the power supply waveform, and suppress the generation of noise. Therefore, particularly when a heating body with a large power or a heating body with a large inrush current is used, the effect of preventing noise from entering other devices and generating abnormal noise is great.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a main part of a heating cooker according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of heating power setting of the heating unit.

FIG. 3 is also a timing chart of control signal waveforms.

FIG. 4 is a diagram showing an example of an AC power supply waveform according to an embodiment of the present invention and a conventional example.

[Explanation of symbols]

 2, 4 Heating unit 2a, 2b Heating body 3a, 3b Phase control circuit 6 Control circuit

Claims (1)

[Claims] 1. A proper number of heating units (2), (4) are provided, and phase control means for these heating units (2), (4) and energization control pattern for each phase control means are output. A heating cooker having a control circuit (6), wherein the heating unit
(2) has a plurality of heating elements (2a), (2b), these heating elements (2a), (2b) are divided into two groups, and the phase control circuit (3a), ( 3b), and the control circuit (6) switches the energization control pattern of the phase control circuit (3a) of one group and the energization control pattern of the phase control circuit (3b) of the other group at regular intervals. A cooker characterized by