JPS62168381A - Induction heating cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an induction heating cooker for general household use.

2. Description of the Related Art In order to make induction heating cookers small, lightweight, low loss, and inexpensive, various methods have been considered.

As part of this, the inventors first provided a first coupling coil and a second coupling coil that were electromagnetically coupled to the heating coil and supplied power to the drive circuit, and the first coupling coil had a voltage An induction heating cooker is proposed in which the second coupled coil is used as a current transformer.

Also number 1. The arrangement of the second coupling coil is as shown in FIG.
As shown in the figure, it has been proposed that the heating coil be wrapped around a part of a magnetic shielding layer provided below the heating coil to reduce unnecessary radiation.

In FIG. 2, 1 is a heating coil, 3 is an inverter that has a switching element 2 and supplies high-frequency power to the heating coil 1, 4 is a drive circuit that drives the switching element 2, and 6 is a center of the heating coil 1. A first coil is provided and is electromagnetically coupled to the heating coil 1 and supplies power to the drive circuit 4.
A coupling coil 6 is provided at the center of the heating coil 1, and a second coupling coil is concentric and has the same diameter as the first coupling coil 6. A magnetic shielding layer 7 is provided below the heating coil 1 to reduce unnecessary radiation. , 8 is a pot.

The first coupling coil 6 is used as a voltage transformer and the second coupling coil 6 is used as a current transformer.

In FIG. 3, 11 is a heating coil, 13 is an inverter that has a switching element 12 and supplies high-frequency power to the heating coil 11, 14 is a drive circuit that drives the switching element 12, and 16 is provided below the heating coil 11. Ferrite magnetic shielding layer 1 that reduces unnecessary radiation
A first coupling coil 16 provided in a part of 7 and electromagnetically coupled with the heating coil 11 to supply power to the drive circuit 14;
The second coupling coil 518 provided in a part of the magnetic shielding layer 17 is a pot. The first coupling coil 15 is used as a voltage transformer and the second coupling coil 16 is used as a current transformer.

Problems to be Solved by the Invention In such a conventional configuration, when the first coupling coil 5 and the second coupling coil 6 are wound concentrically and with the same diameter around the center of the heating coil 1 as shown in FIG. In this case, since the magnetic flux in the second coupling coil e is disturbed by the first coupling coil 6, the operation of the second coupling coil 6 as a current transformer is inhibited.

Moreover, the magnetic flux density at the center of the heating coil 1 is different from the type of pot ((
Therefore, since the output voltage of the first coupling coil 6 is greatly influenced by the pot 8, there is a problem that the drive becomes unstable υ and the switching element 2 is destroyed in some cases.

Furthermore, when the first coupling coil 15 and the second coupling coil 16 are wound around a part of the magnetic shielding layer 17 as shown in FIG. 3, the coupling between the coupling coils 15 and 16 can be reduced. Therefore, the operation of the second coupling coil 16 is similar to that of the first coupling coil 1 when it is wound around the center of the heating coil 11.
However, depending on the position of the pan, the output voltage of the first coupling coil 15 changes greatly, making the drive unstable, and in some cases, there is a problem that the sui-futeng element 12 may be destroyed. Ta.

The present invention solves the above problems by reducing the change in the output voltage of the first coupling coil depending on the type of pot, and preventing the operation of the second coupling coil from being inhibited by the first coupling coil. To provide a highly reliable induction heating cooker that can always operate stably without any problems.

Means for solving the problem of heat generation To achieve this objective, the induction heating cooker of the present invention has the following features:
a heating coil, an inverter having a switching element and supplying high frequency power to the heating coil, a drive circuit driving the switching element, and a first inverter that is electromagnetically coupled to the heating coil and supplying power to the drive circuit.
and a second coupling coil, wherein the first coupling coil is used as a voltage transformer, the second coupling coil is used as a current transformer, and the first coupling coil is arranged on a lower surface of the heating coil. The second coupling coil is arranged magnetically separated from the first coupling coil.

Effect: With this configuration, the change in the output voltage of the first coupling coil due to the type of pot is reduced, and the operation of the second coupling coil is not inhibited by the first coupling coil, so that a stable drive is always achieved. be able to.

EXAMPLE An example of the present invention will be described below with reference to the drawings. Fig. 1 is a sectional view of an induction heating cooker according to an example of the present invention. In the figure, 21 is a heating coil;
3 is an inverter that has a switching element 22 and supplies high-frequency power to the heating coil 21; 24 is a drive circuit that drives the switching element 22; 26 is the heating coil 2;
1 is electromagnetically coupled to supply power to the drive circuit 24, 26 is a second coupling coil, 27 is a magnetic shielding layer provided under the heating coil 21 to reduce unnecessary radiation, and 28 is a pot. be.

The first coupling coil 26 is used as a voltage transformer, and the second coupling coil 26 is used as a voltage transformer.
The coupling coil 26 is used as a current transformer, and the first coupling coil 25 is provided between the lower surface of the heating coil 21 and the magnetic shielding layer 27 below it. First coupling coil 26
is concentric with the heating coil 21, and its diameter is about half the sum of the outer diameter and inner diameter of the heating coil 21. Also the second
The coupling coil 26 is added! ? It has a different diameter and is concentric with the coil 21 and the first coupling coil 26, is located at the center of the heating coil 21, and is arranged magnetically apart from the first coupling coil 26.

In the above configuration, the magnetic flux within the second coupling coil 26 is not affected by the first coupling coil 25, and therefore operates stably as a current transformer. First coupling coil 26
Since the output voltage is almost constant regardless of the type of pot, the drive is stable. Furthermore, in this embodiment, the diameter of the first coupling coil 26 is set to about half the sum of the outer diameter and inner diameter of the heating coil 21, so the magnetic flux within the first coupling coil 26 is large, and a small number of turns is sufficient. It is possible to obtain a high output voltage.

Note that in this embodiment, the second coupling coil 26 is the heating coil 2.
1, it is of course possible to provide it in a part of the magnetic shielding layer 27 for reducing unnecessary radiation.

Effects of the Invention As is clear from the above embodiments, the induction heating cooker of the present invention particularly includes a heating coil, an inverter having a switching element and supplying high frequency power to the heating coil, and driving the switching element. a drive circuit; a first coupling coil and a second coupling coil that are electromagnetically coupled to the heating coil and supply power to the drive circuit; the first coupling coil is used as a voltage transformer 7;
The second coupling coil is used as a current transformer, and the first coupling coil is disposed on the lower surface of the heating coil, so that the magnetic flux in the second coupling coil is
Since it is not affected by the coupling coil, it operates stably as a current transformer. Furthermore, since the first coupling coil provides a substantially constant output voltage regardless of the type of pot, the drive becomes stable.

Therefore, it is possible to provide a highly reliable induction heating cooker.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an induction heating cooker according to an embodiment of the present invention, Fig. 2 is a sectional view of an induction heating cooker showing a conventional technique, and Fig. 3 is an induction heating cooking device showing another conventional technique. It is a sectional view of a container. 21... Heating coil, 22... Switching element, 23... Inverter, 24...
...Drive circuit, 26...First coupling coil, 26...Second coupling coil, 27...
・Magnetic shielding layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Broom Figure 3/31?

Claims (2)

[Claims] (1) A heating coil, an inverter having a switching element and supplying high-frequency power to the heating coil, a drive circuit that drives the switching element, and an inverter that is electromagnetically coupled to the heating coil and supplies power to the drive circuit. one coupling coil and a second coupling coil;
The first coupling coil is used as a voltage transformer, the second coupling coil is used as a current transformer, and the first coupling coil is used as a current transformer.
The coupling coil is arranged on the lower surface of the heating coil, and the second coupling coil is arranged magnetically apart from the first coupling coil. (2) The induction heating cooker according to claim 1, wherein the first coupling coil is provided between the heating coil and the magnetic shielding layer below the heating coil.