JPS6116630Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating cooker capable of driving an electric device that includes a built-in power receiving coil that is electromagnetically coupled to an induction heating coil.

A technology that eliminates the need for a power cord by placing electrical equipment, including a power receiving coil, on the top plate of an induction heating cooker, and by electromagnetically coupling the induction heating coil and the receiving coil to supply power from the cooker to the electrical equipment. This is already well known, and attempts have been made to apply it to kitchen products such as mixers and toasters, and to drive them with induction heating cookers.

Such cookers are usually designed so that the input power when heating a cooking pot can be adjusted from about 200W to about 1200W, but on the other hand, electric appliances such as mixers and toasters consume only about 100W to 500W. be. Therefore, when an electric device is driven with the input set to 1200W, leakage magnetic flux increases, and there is a risk that nearby magnetic devices or electric components inside the cooker will be heated. Another disadvantage is that even though the voltage and current applied to the switching elements and other parts that make up the high-frequency inverter are under a light load, they are the same as when they are fully loaded, which puts an unnecessary burden on each element and accelerates their deterioration. There is.

The present invention was made to solve such problems, and one embodiment will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes an induction heating cooker, on which a cooking pot made of a magnetic material such as iron or the aforementioned cordless electric appliance is placed on a top plate 2 made of an insulating plate such as a ceramic plate. 3 is the power switch,
4 is an input lever switch that changes the load, that is, the input to the cooking pot, from about 200W (displayed as "weak") to about
It can be adjusted up to 1200W (displayed as "strong"). The display "cordless" indicates that when a cordless electrical device is placed on the top plate 2, power will not be supplied unless the lever switch 4 is moved to this position.

Figure 2 shows a circuit block, 5 and 5 are AC power supply connection terminals, 3 is the above-mentioned power switch, 6 is a rectifier circuit, 7 is a choke coil, 8 and 9 are smoothing capacitors, 10 is a high frequency inverter, and induction heating Coil 11, resonant capacitor 12, diode 13
and a transistor 14 functioning as a switching element. 15 is a control transformer;
16 is a magnet switch, and a magnet 17 placed close to the induction heating coil 11 is connected to the top plate 2.
It closes when it is sucked into the cooking pot placed above. 18 is this magnet switch 16
The power supply circuit 19 to which power is supplied from the control transformer 15 via the control transformer 15 is a switch connected in parallel to the magnet switch 16, which controls the specific position of the variable resistor VR operated by the input lever switch 4, that is, the above-mentioned "cordless" Closes when the display position is reached. 2
0 is an inverter drive circuit that provides an on/off signal to the base of the transistor 14, 21 is an R-S flip-flop that controls this inverter drive circuit 20, and 22 is an on-pulse generation circuit that generates an on-pulse that makes the transistor 14 conductive. ,
The flip-flop 21 is set by this on-pulse, and the transistor 14 is made conductive via the inverter drive circuit 20 to maintain the on state. 23
is a pulse interval setting circuit that determines the conduction period of the transistor 14, and the pulse interval is determined by an input adjustment variable resistor VR. This pulse interval setting circuit 23 determines the input to the load; when the pulse interval is short, the input is small, and conversely, when the pulse interval is long, the input is increased. 24 is an off-pulse generation circuit that generates an off-pulse to cut off the transistor 14 after the time determined by the pulse interval setting circuit 23 has elapsed after the generation of the on-pulse; this off-pulse resets the flip-flop 21; It is cut off. 25 is a small load detection circuit that detects a small load or no load by detecting the current flowing to the cathode side of the diode 13 using a current transformer CT.It operates when the input is about 100W or less, and resets the flip-flop 21. The oscillation of the inverter 10 is stopped. 26 is an OR circuit.

Next, the operation will be explained. When a cooking pot made of a suitable material such as iron is placed on the top plate 2, the magnet 17 is attracted upward in the figure, and the magnet switch 16
closes. Therefore, power is supplied to the power supply circuit 18, an on-pulse is generated from the on-pulse generating circuit 22, and the high-frequency inverter 10 oscillates. Then, the heating operation is executed by the input adjusted by the lever switch 4.

For example, if the input is set to "strong" (approximately 1200W) and a cordless electric device such as a mixer is placed in place of the cooking pot, this electric device will not attract the magnet 17, so the magnet switch 16 will open.
The oscillation of the inverter 10 stops. However, when the lever switch 4 is moved and stopped at the "cordless" position, the switch 19 is closed, power is again supplied to the power supply circuit 18, and the inverter 10 oscillates.

Cordless electrical appliances usually have low power consumption, about 500W for toasters, 200W for mixers, and 100W for coffee grinders, so they can
The position of the input lever switch 4 where it operates is approximately
It is sufficient to set it to a level of about 500W. If the input is about 100W or less, the small object load detection circuit 25 will operate and prohibit the oscillation of the inverter 10, so if you remove the electrical equipment with the input lever switch 4 fixed at the "cordless" display position, This small object load detection circuit 25 is activated and the heating operation is stopped.

As explained above, the induction heating cooker of this invention is
When driving a cordless electrical device with a built-in power receiving coil, it supplies an input that matches its power consumption, which prevents heating of surrounding metal materials due to increased leakage magnetic flux, and also prevents heating of surrounding metal materials such as switching elements and other circuit components. unnecessary burdens can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is a circuit block diagram. 1...Induction heating cooker, 4...Input lever switch, 10...High frequency inverter, 16...Magnet switch, 17...Magnet, 19...Switch.

Claims (1)

[Scope of utility model registration request] A high frequency inverter including an induction heating coil and a switching element for regulating oscillation, an input adjustment means for variably controlling the conduction period of the switching element to adjust the input to the load, and a cooking pot made of a magnetic material on the induction heating coil. It includes a magnet switch that detects this when placed and enables the high-frequency inverter to oscillate, and a power receiving coil that is electromagnetically coupled to the induction heating coil, and the power consumption value of the electrical equipment that receives power from the power receiving coil. An induction heating cooker comprising a switch that short-circuits the magnet switch when the inputs of the input adjusting means are set to match.