JPH0612702B2 - Electromagnetic induction heating cooker - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electromagnetic induction heating cooker.

2. Description of the Related Art An electromagnetic induction heating cooker uses an inverter circuit to convert a commercial power source into a high frequency power source and supplies a current to a flat coil. FIG. 4 shows an embodiment of the frequency conversion device. The commercial power source 1 is a rectifying bridge 2 via a switch 11.
It is connected to the. On the output side of the rectifying bridge 2, a choke coil 3, a high frequency bypass capacitor 4, a resonance capacitor 5, a heating coil 6, a diode 7, a transistor 8 and a control circuit 9 constitute an inverter circuit. The control circuit 9 outputs a control signal to the transistor 8, turns the transistor 8 on and off, generates a high-frequency current in the resonance capacitor 5 and the heating coil 6, and heats the pot 10 placed near the heating coil 6. It was

As a power supply means for driving the transistor 8 and the control circuit 9, below the flat heating coil 6,
The two auxiliary coils were provided at positions facing each other along the radial direction of the flat plate-shaped coil 6. In addition, the power supply line (the line from a to the switch in FIG. 4) in the device uses an electric wire.

Problems to be Solved by the Invention Generally, since the mounting portion a of the power supply wire to the device is located at the rear of the device and the switch 11 is located at the front of the device, the power supply line in the device is considerably long. There are problems such as high cost and deterioration of workability, and at the same time, there is a problem that the auxiliary coil is adversely affected.

Therefore, the present invention provides an electromagnetic induction heating cooker which does not adversely affect the auxiliary coils 12a and 12b and improves workability.

Means for Solving Problems The technical means of the present invention for solving the above problems is to mount an electromagnetic line on a printed circuit board so as to be substantially parallel to the auxiliary coil.

Action The action of this technical means is that the magnetic flux passing through the auxiliary coil and the magnetic flux generated from the power supply line are not electromagnetically coupled.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1 and FIG. 2, the auxiliary coil 12 is attached to the ferrite cores 22 a and 22 b provided under the flat coil 6.
A and 12b are wound. In addition, the auxiliary coil 12a,
Below the 12b is a printed circuit board 14 on which the power supply line 13 is printed. This power line 13 is the auxiliary coil 1
Printed circuit board 1 so that it is substantially parallel to 2a and 12b
It is printed on page 4. The power supply line 13 printed on the printed circuit board 14 is connected to the power supply wire 15 on one side and the switch 11 on the other side.

Next, the operation of this embodiment will be described.

First, the operation of the auxiliary coils 12a and 12b will be described with reference to FIG. When the transistor 8 starts to turn on, its collector current has a small value, and the base current for driving it may be small. Therefore, a DC power supply with a small capacity can be used. Next, when the collector current Ic flows through the transistor 8, an induced current is generated in the auxiliary coil 12a, which can be used as it is as the base current of the transistor 8. The base current value at this time is the auxiliary coil 12a.
It can be set arbitrarily by adjusting the number of turns and the mounting distance from the flat coil 6. One auxiliary coil 1
An induced current is also generated in 2b, but when the transistor 8 is on, the other transistor 18 is off, so the induced current is stored in the capacitor 17 as a charge voltage as it is.

Next, in the case where the transistor 8 is turned off, the other transistors 18 are turned on at the same time, and the charge voltage of the capacitor 17 becomes the base voltage of the transistor 8.
It is applied in the reverse bias direction of the emitter. At this time, a current also flows from the resistor 19 and the auxiliary coil 12a in the forward direction, but if the number of turns of the other auxiliary coil 12b is set so that the voltage can flow a reverse bias current higher than that, the forward direction can be increased. The base current is canceled and the reverse bias current flows.

The relationship between the auxiliary coils 12a and 12b performing the above operation and the power supply line 13 will be described. If power line 1
3 and the auxiliary coils 12a and 12b intersect,
Both are electromagnetically coupled, and the induced current generated by the electromagnetic coupling is added to the induced current generated in the auxiliary coils 12a and 12b, so that the originally set predetermined induced current cannot be obtained.

On the other hand, the auxiliary coils 12a and 12b and the power supply line 1
When 3 and 3 are made substantially parallel, electromagnetic coupling does not occur, so that a desired induced current can be obtained and the auxiliary coils 12a, 12
b operates stably.

As described above, according to the present invention, it is possible to reduce the cost and the work for mounting the power supply line by mounting the power supply line on the printed circuit board, and to install the auxiliary coil in parallel with the power supply line. By doing so, the auxiliary coil can be operated stably.

[Brief description of drawings]

FIG. 1 is a plan view showing a positional relationship between an auxiliary coil and a power supply line in an embodiment of the present invention, and FIG. 2 is a sectional view showing a relationship between the flat coil and the auxiliary coil, and a printed circuit board, and FIG. The figure shows the wiring diagram of the auxiliary coil and the transistor,
FIG. 4 is a wiring diagram of the frequency conversion device. 6 ... Flat coil, 12a, 12b ... Auxiliary coil,
13 ... power line, 14 ... printed circuit board.

Claims (1)

[Claims] 1. A heating coil to which a high-frequency current is supplied, a switching element for inducing a voltage by a magnetic force of a heating coil installed under the heating coil to oscillate at a high frequency, and an auxiliary coil which supplies the voltage to a switching control circuit. And a printed circuit board to which at least a power supply line is installed below the auxiliary coil group, and the power supply line is formed to be substantially parallel to the auxiliary coil group.