JPH01115080A - Cooker - Google Patents

Abstract

PURPOSE:To enable heating output to be raised with simple operation at need by providing a high frequency oscillation circuit, an invertor circuit which supplies power to the high frequency oscillation circuit, an operating means, and a means which raises the output of the invertor circuit for a certain time at operation of the operation means. CONSTITUTION:When cooking, if a user presses an output up key 42a, an output setting signal B is issued only for a certain time 't' from an output setting circuit 32 by the instruction of a microcomputer 31. This output setting signal B is higher in voltage level than an output setting signal A. When the output setting signal B is issued, the logic '1' term of the output pulse of a pulse width modulation circuit 33 becomes long and ON/OFF duty of a transistor 16 becomes large and output of an invertor circuit 10 rises and the heating output goes up above the rated one. Then, the microcomputer 31 changes a certain time 't' according to the weight of food detected by a weight sensor 41. That is, the more the food amount is, the longer the certain time 't' is extended. Hereby, the heating output can be raised at need and further with simple operation.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a cooking appliance such as a microwave oven.

(Prior art) Cooking appliances such as microwave ovens step up the commercial AC power supply voltage using a high-voltage transformer, rectify it using a half-wave voltage doubler rectifier circuit consisting of a high-voltage capacitor and a high-voltage diode, and apply it to a magnetron. . Then, a switch was installed in the current path between the power supply and the high-voltage transformer, and the switch was turned on.

By turning it off, it is possible to reduce the heating output.

(Problems to be Solved by the Invention) By the way, when cooking in a microwave oven, depending on the amount of food, the heating output may be insufficient, resulting in poor cooking quality or prolonged cooking time.

However, in a microwave oven, although it is possible to reduce the heating output, it is not possible to increase the heating output beyond the rated value, and the fact is that the above-mentioned problems are tolerated.

This invention was made in view of the above circumstances,
The purpose of this is to be able to increase the heating output as needed with ntg operations, which allows food to be cooked to a good quality regardless of whether the food is being watched, and to shorten the cooking time. Our goal is to provide a cooking device that enables

[Structure of the Invention] (Means for Solving the Problems) A high frequency oscillation circuit, an inverter circuit that supplies power to the high frequency oscillation circuit, an operating means, and an output of the inverter circuit that is constant when the operating means is operated. A means for increasing the time is provided.

(Function) When the operating means is operated, the output of the inverter circuit increases for a certain period of time, increasing the heating output.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a commercial AC power supply, and the power supply 1 is connected to a fuse 2. First door switch 3a, second door switch 3
Door monitor switch (short switch) 3 via b
c is connected. A magnetron cooling fan motor 4 and a turntable drive motor 5 are connected in parallel to the door monitor switch 3C.

Furthermore, 1! For source 1, fuse 2. An inverter circuit 10 is connected via the first door switch 3a and the second door switch 3b.

The inverter circuit 10 includes a diode bridge 11, a choke filter 12. It has a rectifier circuit consisting of a smoothing capacitor 13, and a series resonant circuit consisting of a primary coil 14a of a high voltage transformer 14 and a capacitor 15 is connected to the output end of the rectifier circuit. The collector-emitter of an NPN transistor 16 and a damper diode 17 are connected in parallel. That is, transistor 1
6 is turned on and off to excite a resonant circuit and cause a high frequency current to flow through the negative coil 14a.

Thus, a high frequency oscillation circuit 20 is connected to the output end of the inverter circuit 10.

The high-frequency oscillation circuit 20 includes a high-voltage capacitor 21 and a high-voltage diode 22 in the secondary coil 14b of the high-voltage transformer 14.
．． The anode and cathode of the magnetron 24 are connected through a half-wave voltage doubler rectifier circuit consisting of 23. Further, the anode of the magnetron 24 is grounded, and the cathode (heater) is connected to the secondary filter 14C of the high voltage transformer 14.

On the other hand, a control unit 30 is connected to the power supply 1 via a fuse 2 and a step-down transformer 6.

The control section 30 performs overall control of the microwave oven, and is mainly composed of a microcomputer 31. Then, an output setting circuit 32 is connected to the microcomputer 31, and a pulse width modulation circuit (P) is connected to the output setting circuit 32.
WM circuit) 33 is connected. The output setting circuit 32 is
It emits an output setting signal of a voltage level according to a command from the microcomputer 31. Pulse width modulation circuit 3
3 pulse width modulates the "sawtooth" signal emitted from the oscillation circuit 34 using the output setting signal from the output setting circuit 32. Therefore, the pulse width modulation circuit 3
The output of 3 is sent to the inverter circuit 1 as a switching signal.
0 to the base of transistor 16.

Also, the weight sensor 4 is connected to the microcomputer 31.
1 and the operating section 42 are connected. The weight l sensor 41 is
It detects the weight of food in a heating chamber (not shown). The operation section 42 is for setting cooking conditions and has an output up key 42a.

Next, the operation of the above configuration will be explained with reference to FIGS. 2, 3, and 4.

The food is placed in the heating chamber, the door is closed, the desired cooking time is set using the operating section 42, and the cooking start operation is performed.

Then, according to a command from the microcomputer 31, the output setting signal A is generated from the output setting circuit 32. In this way, as shown in FIG. 3, the "sawtooth" signal emitted from the oscillation circuit 34 is pulse width modulated by the output setting signal A, and the inverter circuit 10
The transistor 16 turns on and off.

When the transistor 16 is turned on and off, the resonant circuit is excited, a high frequency current flows through the primary coil 14a, and the magnetron 24 operates in oscillation. In other words, high-frequency radio waves are supplied during heating, and dielectric heating cooking begins.

The heating output in this case is rated.

When the user presses the output up key 42a during cooking,
In response to a command from the microcomputer 31, the output setting signal B is generated from the output setting circuit 32 for a certain period of time t.

This output setting signal B has a higher voltage level than the output setting signal A.

When the output setting signal B is issued, as shown in Fig. 4,
The logic "1" period of the output pulse of the pulse width modulation circuit 33 becomes longer, and the on/off duty of the transistor 16 becomes larger. This increases the output of the inverter circuit 10 and increases the heating output beyond the rated value.

At this time, the microcomputer 31 is! 1 sensor 4
The fixed time t is changed according to the weight of the food detected in step 1. That is, the larger the amount of food, the longer the constant time WRt is.

After a certain period of time t has elapsed, the microcomputer 31 causes the output setting circuit 32 to generate the output setting signal A again.
Return heating output to rated value.

Furthermore, when the set cooking time has elapsed, the microcomputer 31 stops driving the inverter circuit 10 and stops the oscillation operation of the magnetron 24.

In other words, cooking is finished.

Therefore, if the user determines that the heating output is insufficient during GL cooking, the heating output can be increased immediately by simply pressing the output up key 42a, and the desired quality of cooking can be achieved. It is possible.

In particular, since the heating output increase time is limited to a certain time t, overheating does not occur.

Moreover, since the fixed time t is automatically changed according to the condition of the food, such as its weight, the optimum amount of heating can be obtained, and a1g! The results are even better.

Furthermore, by increasing the heating output, it is also possible to shorten the cooking time.

In the above embodiment, a weight sensor is used as a sensor for detecting the condition of food, but other sensors may also be used. In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist.

[Effects of the Invention] As described above, according to the present invention, there is provided a high-frequency oscillation circuit, an inverter circuit that supplies power to the high-frequency oscillation circuit, an operating means, and an output of the inverter circuit when the operating means is operated. Since we have provided a means to increase the heating output for a certain period of time, it is possible to increase the heating output as needed and with a simple operation.This makes it possible to cook food to a good quality regardless of the amount of food, and also to reduce the cooking time. It is possible to provide a cooking device that makes it possible to shorten the time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a control circuit in one embodiment of the present invention, FIG. 2 is a diagram for explaining changes in heating output in the same embodiment, and FIGS. 3 and 4 are respectively in the same embodiment. FIG. 3 is a diagram for explaining the operation of pulse width modulation in FIG. DESCRIPTION OF SYMBOLS 10... Inverter circuit, 20... High frequency oscillation circuit, 30... Control part, 42a... Output up key (operation means). Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) A high-frequency oscillation circuit, an inverter circuit that supplies power to the high-frequency oscillation circuit, an operating means, and a means for increasing the output of the inverter circuit for a certain period of time when the operating means is operated. Cooking device. (2) The cooking device according to claim 1, wherein the certain period of time is determined according to the detection result of a sensor that detects the condition of the food. (3) The cooking device according to claim 2, wherein the sensor is a weight sensor that detects the weight of the food.