JPS6342835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has an induction heating coil in the main body of the device, and uses current flowing through the heating coil to heat a pot (mainly iron-based) placed on the coil. The present invention relates to a device in which a secondary induction coil is brought close to the coil and a small accessory device that operates a mixer or the like without a power cord using the electric power induced in the secondary induction coil.

Conventional electromagnetic cookers generally use an inverter circuit to generate high-frequency power in an induction heating coil, and when a pot is brought close to such an induction heating coil, the pot is heated by the induction heating effect. Generally, an iron-based pot, such as an enamel pot, is suitable for this pot. However, unlike gas or electric heaters, keeping the inverter circuit running even when the pot is not on the heating coil makes it difficult to tell when the device is running, and the parts inside the device are not operating. If it continues, the lifespan will be shortened.

In addition, when a small load such as a knife or fork is placed on the heating coil, the small load detection device is activated to prevent current from continuing to flow through the heating coil, and prevents abnormal heating of the knife or fork. Prevents dangers such as burns. For example, a device equipped with a small load detection device in this way is
It has already been invented in the publication No.

By the way, in the electromagnetic cooker having the above-mentioned small load detection device, a secondary induction coil is provided at the bottom to receive the induced electromotive force of the heating coil, and the electric power induced in the secondary induction coil is used to generate, for example, a mixer for grinding coffee beans. In addition, it is conceivable to operate small auxiliary equipment such as a small ultrasonic cleaner in combination with a magnetostrictive element.

However, because of the small load detection device mentioned above, if the load on a small accessory device is small, current will not flow through the heating coil, making it impossible to operate the accessory device.

The present invention was devised by paying attention to this point. First, an oscillator that oscillates a relatively high frequency radio wave that is activated by the power induced in the secondary induction coil is provided on the accessory equipment side, and A receiver is provided, and the receiver disables the operation of the small load detection device, allowing the secondary coil of the auxiliary equipment to continue being guided.

Embodiments of the present invention will be described below with reference to the drawings.

1 is a power supply circuit that rectifies a commercial AC power supply, 2
3 is a duty cycle setting circuit for power control, which extracts a pulse synchronized with the zero voltage of the power supply circuit 1. It separates into on-pulse and off-pulse. Reference numeral 4 denotes a zero voltage synchronous on/off control circuit to which these on/off pulses are input as trigger pulses, and the circuit is turned on by the on pulse and turned off by the off pulse. 5 is a gate oscillation circuit that oscillates when the control circuit 4 is on and stops oscillating when it is off; 6 is an inverter supplied with power from the power supply circuit 1 and controlled on/off by a signal from the gate oscillation circuit 5; 7 is a high-speed diode that is a component of the inverter circuit 6; 8 is a current detector that detects the current flowing through the diode 7; 9 is a current detector;
1 is a waveform shaping circuit that shapes the output voltage of the detector 8; and 10 is an on-pulse control circuit that controls on-pulses based on the output of the waveform shaping circuit 9. Reference numeral 11 denotes a passive device which will be described later.

FIG. 2 shows a circuit example of the inverter circuit 6, in which terminals 11, 11 are connected to the power supply circuit 1, and a gate oscillation circuit 5 is connected to the gate of the thyristor 12.
A pulse signal G from is applied. 7 and 8 are the high-speed diode and current detector, respectively, and terminals 13 and 13 of the detector 8 are connected to the passive device 11 described above.
It is connected to the waveform shaping circuit 9 via. 14 is an induction heating coil, and 15 is a cooking pot placed on this coil 14 via an insulating plate.

Next, the operation of small object load detection will be explained with reference to FIG. 2. First, when a normal pot 15 is placed, the inverter circuit 6 is turned on and the pot 15
is heated. At this time, the output of the current detector 8 is
Because the load is large, the waveform is narrow (width approximately) as shown by the solid line.
10 μs), and even after waveform shaping, it remains a narrow pulse as shown by the solid line. In such a case, the on-pulse control circuit 10 does not operate, and the on-pulse is passed directly to the zero voltage synchronous on/off control circuit 4.
In addition, this control circuit 4 is power-controlled only by the duty cycle setting circuit 3.

On the other hand, if a small item such as a knife or fork is placed instead of the pot, the power consumption in the load is small, so the current in the inverter circuit 6 is not attenuated, and a large current flows through the high speed diode 7. Therefore, the output of the current detector 8 and the output pulse of the waveform shaping circuit 9 are wide pulses (width approximately
14μs). In such a case, the on-pulse control circuit 10 operates and short-circuits the on-pulse, and the on-pulse is no longer supplied to the zero voltage synchronous on/off control circuit 4, and the on/off control circuit 4 is turned off and the gate is closed. The oscillation circuit 5 stops oscillating, and the inverter circuit 6 also stops operating. Note that the on-pulse control circuit 10 is configured to self-maintain once it starts operating. Alternatively, a delay circuit may be incorporated into the on-pulse control circuit 10 to detect and turn off the inverter circuit 6 after a certain period of time has elapsed.

Reference numeral 16 denotes a secondary induction coil installed in a small auxiliary device 17 corresponding to the induction heating coil 14. Electric power induced in this secondary induction coil is used to power the motor in the case of a coffee grinder. , and also excites the excitation coil of the magnetostrictive element to operate the attached equipment. Then, the induced power of the secondary induction coil 16 activates the high frequency transmitter 18, and the radio waves from the transmitter 18 disable the operation of the small object load detection circuit 20 at the receiver 19 of the main body. act. For example, when the accessory device 17 is used, this can be realized by turning off the circuit of the detection current detector 8. That is, the receiver of the electromagnetic cooker body acts as a passive device.

As explained above, the combination device of the electromagnetic cooker and auxiliary equipment of the present invention is such that the load on the auxiliary equipment is small when an electromagnetic cooker equipped with a circuit that distinguishes and detects pots and small items is used. However, a release device that emits a signal to release the operation of the small load detection device operated by the secondary coil is built-in, and the electromagnetic cooker body is equipped with a built-in release device that outputs a signal to release the operation of the small load detection device operated by the secondary coil. Since it is equipped with a passive device that operates to cancel the small load detection operation, only when the attached device is used, the operation of the small load detection circuit in the electromagnetic cooker itself can be released and the attached device can be operated. If this is done and the attached equipment is removed, the small load detection device will operate again, detect the small load, and will not automatically start heating.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a main circuit diagram, Fig. 3 is a waveform diagram for explaining the same example, and Fig. 4 is an auxiliary device connected to an electromagnetic cooker. FIG. 3 is a cross-sectional view of main parts showing a placed state. 1...Power supply circuit, 2...Zero voltage synchronous pulse generation circuit, 3...Duty cycle setting circuit, 4
... Zero voltage synchronous on/off control circuit, 5 ... Gate oscillation circuit, 6 ... Inverter circuit, 7 ... High speed diode, 8 ... Current detector, 9 ... Waveform shaping circuit, 10 ... On-pulse control circuit , 14...
Induction heating coil, 15...cooking pot, 16...secondary induction coil, 17...attached equipment, 18...transmitter, 19...receiver, 20...small object load detection circuit.

Claims (1)

[Claims] 1. An induction heating coil is provided in the main body of the device, and by passing an alternating current through the coil, a metal container, mainly made of iron, placed outside the device is heated on the coil, and the load on such containers, etc. is reduced. an electromagnetic cooker body having a small load detection device that does not continue energizing the coil when the value is smaller than a predetermined value; and at least a secondary induction coil receiving induction from the induction heating coil, the secondary induction coil In combination with an auxiliary device that operates in a predetermined manner using electric power induced by the electromagnetic cooker, the auxiliary device has a built-in release device that emits a signal to release the operation of the small load detection device of the cooker main body, and the electromagnetic cooker A combination device of an electromagnetic cooker and auxiliary equipment, characterized in that the main body is provided with a passive device that operates to release the small load detection operation of the small load detection device in response to a signal from the release device. .