JPS5971282A - Induction heating inverter - 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 This invention particularly relates to static induction transistors (hereinafter referred to as SIT).
This invention relates to an improvement of an inverter device for induction heating using an inverter device.

As is well known, as an inverter device for induction heating used as the above-mentioned SIT total switching element, the one shown in FIG. 1 has been generally known. That is, this circuit alternately switches the SIT JJ 12 by applying r-t signals to its ff-) terminals 13 and 14, and transfers the AC power obtained at the connection point of both SITs 11 and 72 to the capacitor. Co and coil L are supplied to another load resonant circuit 15. In this case, for example, the capacitor c of the load resonant circuit 15
The voltage across the terminal o is supplied to an automatic frequency control circuit (not shown) that generates a pulse signal of a predetermined period having a phase difference according to the input voltage, and the pulse signal 2y-to terminal 13.1 is supplied.
4 to the SITs 11 and 12, the switching operation is controlled so as to be stable. In addition, in FIG. 1, DI.

D2 is a diode %C11C2 is a voltage dividing capacitor, 16
．． 17 is a power supply terminal to which DC voltage elements B and -B are respectively applied.

By the way, in the conventional induction heating inverter device as described above, when both SIT 71 and J 2 are turned on, an excessive current flows and both SIT 71 and J 2 are turned on.

There is a problem that 12 may be damaged. Therefore, conventionally, the ff-) signals supplied to both dart terminals 13 and 14 are as shown in FIG. 2 (a) and (b) IC, respectively, and both SIT J 1 and I I'm trying to make sure this doesn't happen. In this case, there will be a period when both SITs I J and J j are in the off state, but at this time, current flows through the diodes D1 and D, and the load resonant circuit 1
5 so that the current does not become discontinuous. However, the characteristics of the SITs 11 and 12, field effect transistors FET, etc. have been improved year by year, and the speed and withstand voltage have become higher and higher.
1.The problem is that it is not suitable for use with large amounts of power because of its high-speed cut-off characteristics and very low withstand voltage limits.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an extremely good induction heating inverter device that has a simple configuration, operates stably, and is suitable for use with large amounts of power.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 3, the same parts as in FIG. 1 are designated by the same symbols, and only the different parts will be described here. That is, the diode DI shown in FIG.
r D2 t'' was deleted, and both 5IT11.12f were connected by a coil L as an inductance element, AC power was extracted from the midpoint of the coil L, and the AC power was supplied to the full load resonant circuit 15. This is a different point from conventional methods.

According to the above configuration, when both BITs 11 and 12 are turned on for a short period of time, the current is limited by the action of the coil L, so it is possible to prevent the SITs 11 and 72 from being damaged.

Furthermore, since the SIT IJ, 12 has the property of allowing current to flow in both directions in the on state, the diodes D1, D2 are not required. Therefore, the circuit shown in FIG. 3 has two terminals 5ITII and 12 as shown in FIGS.
By supplying a dart signal that does not turn off both f, stable operation can be achieved.

Therefore, the diode Dl ID2 as in the conventional case is not required, so that it is suitable for use with a large amount of power and the configuration can be simplified.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

Therefore, as described in detail above, according to the present invention, it is possible to provide an extremely good inverter device for induction heating that has a simple configuration, operates stably, and is suitable for use with high power.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram showing a conventional induction heating inverter device, Figs. 2(a) and (b) are timing diagrams for explaining the operation of the circuit shown in Fig. 1, and Fig. 3 is a timing diagram for explaining the operation of the circuit shown in Fig. 1. FIGS. 45(a) and 45(b) are a circuit diagram showing an embodiment of the inverter device for induction heating according to the invention, and are timing charts for explaining the entire operation of the embodiment. 11.12...SIT% 13.14...Dirt terminal, 15...Load resonant circuit, 16.17...Power supply terminal, D1*D2...Diode, co to C2...
Capacitor, L * L 6...Coil. Applicant's agent Patent attorney Takehiko Suzue 6- Figure 1 16 Figure 2 (a) (b) Figure 3 6 Figure 4 ('') n (b)

Claims (1)

[Claims] In an inverter device for induction heating in which AC power obtained by alternately switching a plurality of pairs of static induction transistors is guided to a load resonant circuit, the plurality of pairs of static induction transistors are coupled by an inductance element. The AC power is extracted from the midpoint of the inductance element and supplied to the load resonant circuit, and the plurality of pairs of electrostatic induction type transistors are supplied with a switching signal that does not turn off any of the plurality of pairs of electrostatic induction type transistors. An inverter device for induction heating, which is characterized in that it is configured to supply power to transistors.