JPS6019352Y2 - induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating cooker equipped with a static power converter having a semiconductor heavy duty control element for converting commercial power into high frequency power.

In general, induction heating cookers having a static power converter have an input current of about one cycle, so a large manual power switch is provided to turn the power on or off.

In this case, since a large current of about 13 A is manually opened and closed, problems such as arc blown occurred.

Also, a configuration has been proposed in which the power relay is turned on or off using a small switch, but in this case, there are drawbacks such as an increase in the number of parts needed to newly provide the power relay.

By the way, in a static power converter, there is substantially no power consumption unless the power control element is driven.

The present invention has been developed in view of this point, and the power control circuit is connected to the gate of the power control element to perform on/off control of the power supply, so that the power control element also functions as a power switch.

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

In Figure 1, 1 is an AC power supply, 2 is a rectifier circuit, 3 is a choke coil, 4 is a capacitor, 5.6 is a semiconductor power control element, and 7 and 8 are connected in antiparallel to power control elements 5 and 6, respectively. The diode 9 is a commutation coil that forms a commutation circuit together with the commutation capacitor 10, and also serves as a heating coil for inductively heating the load 11.

Reference numeral 12 denotes a control circuit that applies gate pulses to the gates of the power control elements 5 and 6 via pulse transformers 13 and 14 to control on/off of the power control elements 5 and 6, and these constitute an inverter circuit. There is.

15 is a fan motor that cools the power control elements 5, 6 and the heating coil; 16 is a power transformer that constitutes the power supply section of the control circuit 12; and 17 is a manual switch that controls power supply to the fan motor 15 and the power transformer 16. It is configured to operate in conjunction with a switch 18 that stops inputting signals from the inverter circuit to the control circuit 12.

In such a configuration, when the switches 17 and 18 are closed, the AC power source 1 is converted to DC through the side current circuit 2, and then inversely converted to high frequency through the choke coil 3 and capacitor 4, supplying power to the load. is supplied.

Switch 17. ．． When 18 is opened, the power control elements 5,
Since the ignition pulse No. 6 disappears, the operation of the inverter circuit stops.

At the same time, the power supply circuit to the fan motor 15 and the power transformer 16 is also cut off, so that power consumption is substantially eliminated.

At this time, the switches 17 and 18 may be small-capacity ones, and may be configured with, for example, a reed switch operated by a magnetic field, a thermal reed switch, or a bimetallic switch.

FIG. 2 shows a specific configuration of the control circuit 12. When the switch 18 is opened, the transistor 19 is turned off.
Transistor 20.21 constituting the inhibiting means is turned on, and transistor 22.23 for pulse amplification is turned off.

As a result, the supply of gate pulses from the gate pulse generation circuit 24 is stopped, and the operation of the inverter circuit is stopped.

As is clear from the above description, according to the present invention, since the power control element also serves as the power switch, there is no need to manually open and close a large current, and arcing can be prevented.

Furthermore, even if a surge voltage from a commercial power supply enters the equipment, the semiconductor power control element is sufficiently protected.

Further, since the manual switch only needs to have a small capacity, the switch can be operated easily and no loud contact opening/closing noise is generated.

It also has great practical value, such as miniaturization and cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of the same control circuit. 5.6...Power control element, 12...Control circuit, 17.18...Switch.

Claims (1)

[Scope of utility model registration request] a static power converter that converts commercial power to high-frequency power;
a first switch that opens and closes signal input to a control circuit connected to a gate of the semiconductor power control element; and a first switch that operates in conjunction with the first switch to control the control circuit. Induction heating cooking that includes a second switch that opens and closes the power supply of the circuit, connects the series circuit of the second switch and the power supply of the control circuit to the commercial power supply, and does not have a power switch directly connected in series to the commercial power supply. vessel.