JP3384685B2 - Noise treatment device for microwave cooking device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise processing device in a microwave heating cooker for heating food such as food by radiating microwaves from a magnetron.
The present invention relates to a noise processing device in a microwave heating cooker capable of preventing a noise component generated during microwave radiation from being output to the outside.

[0002]

2. Description of the Related Art A conventional microwave oven is disclosed in JP-A-7-5515.
As shown in FIG. 1 of Japanese Unexamined Patent Publication No. 2 publication, noise generated when the magnetron radiates microwaves for heating food is prevented from leaking to the outside of the main body through a power cord by using a coil and a capacitor. In order to prevent the magnetron itself from going outside, Japanese Patent Laid-Open No. 63-1
As shown in Japanese Patent No. 16388, a choke coil and a low pass filter of a feedthrough capacitor are incorporated in the heater lead portion.

[0003]

However, in the above-mentioned technique, since the circuit for noise prevention is formed by all passive elements, the characteristic for preventing noise is almost fixed, and a large noise is generated at a specific frequency. It is difficult to improve the characteristics only at that frequency, and the frequency at which large noise is generated is different for each microwave oven model, so a noise filter with high attenuation in a wide frequency band is developed and commonly used. It will be. However, even with this method, noise is not sufficiently suppressed, and there is a problem that other communication equipment malfunctions due to noise leaked from the main body to the outside.

Therefore, an object of the present invention is, in a microwave heating cooker using a magnetron, the level of noise components output to the heater side of the magnetron when microwaves are radiated from the magnetron for heating food. It is an object of the present invention to provide a noise processing device in a microwave heating cooker that can be canceled according to the above and can be prevented from being output to the outside.

[0005]

According to a first aspect of the present invention, there is provided a noise processing device for a microwave heating cooker , wherein when a magnetron radiates microwaves to food to heat the food, a high voltage is applied to the magnetron and a low voltage. Convert voltage to voltage
Output to the heater lead wire provided between the high voltage transformer
Depending on the noise component
Cancels the noise component that goes out from the source code
Is configured to apply a signal to the power cord .

The noise processing device according to the first aspect is configured in this way, and the characteristic of actively operating and blocking noise according to the level of the noise component is flexibly adjusted by following the level of the noise component. Therefore, it is possible to stably prevent the noise component from being output to the outside regardless of the level of the generated noise component.

[0007] noise processing apparatus in the microwave cooker according to claim 2, the noise processing apparatus according to claim 1, and detecting means for detecting the noise component at a predetermined position, by said detecting means The detected noise component
Phase is inverted, and the phase-inverted noise component is shaken.
A noise processing unit for adjusting the width, and is configured to apply the noise component whose amplitude is adjusted by the amplitude adjusting unit to the power cord.

The noise processing apparatus according to the second aspect is configured in this way, and the detecting means, the phase inverting means, and the amplitude adjusting means actively operate according to the level of the noise component. Therefore, regardless of the level of the noise component generated by using each of these means, it is possible to stably prevent the noise component from being output to the outside.

In the noise processing device in the microwave heating cooker according to a third aspect, a predetermined position for the noise component detection by the detection means of the noise processing device according to the second aspect is a noise component generation source. It is configured to be either the closest position or the position immediately before the noise component is applied to the power cord .

The noise processing device according to the third aspect is configured in this way, and the noise component is selected by arbitrarily selecting one of the position closest to the source of the noise component and the position where the noise component is likely to be affected outside. Can be detected, so that the noise component to be prevented can be effectively detected.

According to a fourth aspect of the present invention, there is provided a noise processing device in a microwave heating cooker , wherein the food is heated by heating the food.
Magnetron that radiates microwaves to the product and the power supply
Power cord connected to the
It is installed between the netron and low power from the power cord.
A high-voltage transformer for converting the pressure into a high voltage, and the high-voltage transformer
Heater provided between the heater and the magnetron heater.
And a microwave heating cooker including:
The heater lead wire at the time of microwave irradiation of the magnetron
Depending on the noise component output to the
Signal that cancels the noise component that goes out to the outside
Is configured to be applied to the power cord .

The noise processing device according to the fourth aspect is configured in this way, and actively operates according to the level of the noise component.
Characteristics to prevent noise are added to the noise component level.
Therefore, since it is flexibly adjusted, the noise component
The noise component is output to the outside regardless of the bell.
Stability can be prevented.

According to a fifth aspect of the present invention, there is provided a noise processing device for a microwave heating cooker, wherein the power cord and the high voltage transformer are provided .
A noise filter is provided between the lance and the low pressure side .

Since the noise processing device according to the fifth aspect is configured as described above, it is possible to prevent the noise component from being output to the outside at a position where the noise component is most likely to have an effect on the outside. Moreover, it is possible to reliably prevent the noise component from being output to the outside.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings using a microwave oven. The cooking operation of the microwave oven itself is not explained here,
The operation for canceling the noise component contained in the output signal of the magnetron will be described.

FIG. 1 is a schematic block diagram showing an electrical configuration of a microwave oven according to an embodiment of the present invention. In the figure, a microwave oven is provided in the magnetron 1 that radiates microwaves to food for cooking food, and the lead wire 9 of the heater of the magnetron 1, and the noise component output to the lead wire 9 side when microwave is radiated is high voltage. Side, a ferrite ring 2 for detecting by electromagnetic induction, a high-voltage transformer 3 provided between the magnetron 1 side (high-voltage side) and the power supply side (low-voltage side) for voltage conversion, and the operation of the microwave oven intensively A control unit 4 for controlling, an LC filter, and a noise filter 5 conventionally provided to suppress noise components on the side of the power cord 7 and to cancel high-frequency noise components generated during microwave radiation of the magnetron 1. The noise processing unit 6 is included. The detailed configuration of the noise processing unit 6 will be described later.

In operation, when cooking is started in the microwave oven and microwave is radiated from the magnetron 1 to the food, the ferrite lead 2 causes high frequency coupling from the heater lead wire 9 and a point Q in the figure. A signal e _{i of} a high-frequency noise component generated during microwave radiation
Is detected and given to the noise processing unit 6. The noise processing section 6 creates a waveform substantially + _-inverse of the waveform of the given signal e _i , and appropriately increases or decreases the magnitude (amplitude) of the signal e _i to obtain the signal e.
_o is generated and applied to the point P of the power cord 7. This cancels the noise component that goes out through the power cord 7 and prevents the noise from going out.

FIG. 2 is a block diagram showing an electrical configuration of the noise processing section 6 of FIG. The noise processing unit 6 is composed of an inverting amplifier circuit having resistors Ri and Rf as shown in the figure. In this inverting amplifier circuit, e _i / Ri + e _o / Rf
Since = 0, the signals e _i and e _o have opposite phases. Further, the amplification factor of the signal can be adjusted by appropriately setting the values of the resistors Ri and Rf. This amplification factor is the degree of signal attenuation / amplification determined by the constant of each circuit in FIG. 1 between the detection point (point Q) of the signal e _{i in} FIG. 1 and the input point (point P) of the signal e _o . It is set accordingly.

As described above, since the noise processing section 6 operates differently from the conventional one, that is, operates according to the level of the signal e _i , the voltage waveform in the reverse direction corresponding to the level of the noise (signal e _i ) is generated. (Signal e _o ) can be generated and applied to the power cord 7 to cancel the noise emitted from the power cord 7 to the outside.

The noise processing section 6 uses an inverting amplifier circuit to perform both the phase inversion processing and the amplification processing of the signal e _i , but the phase inversion circuit and the amplification circuit are separately provided. You may make it provide and perform each process individually.

FIG. 3 is a schematic block diagram showing an electric configuration of a microwave oven according to another embodiment of the present invention.
In FIG. 1 described above, the noise component is obtained by coupling from the heater lead wire 9 in a high frequency, but as shown in FIG. 2, a waveform obtained from a portion where the voltage waveform finally applied to the power cord 7 is less affected. May be used. Other configurations are similar to those of FIG. In this case, as shown in FIG. 2, the noise processing section 6 detects the noise component (signal e _i ) at the point Q ′ immediately before the noise filter 5, and
In the same manner as above, the signal e _o is applied to the point P, thereby canceling the noise component leaking from the power cord 7 to the outside. Since the power supply side has a relatively low voltage, the high frequency noise component (signal e _i ) in the signal at the point Q ′ can be detected via the capacitor 8. The capacity of the capacitor 8 is determined according to the frequency of the noise component.

In the case of FIGS. 1 and 3 described above, noise
Signal e for canceling components _oTo power cord 7
Although it is applied, it is effective that the noise component leaks to the outside
In order to prevent this, apply it to the ground wire in the figure.
May be.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an electrical configuration of a microwave oven according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of a noise processing unit in FIG.

FIG. 3 is a schematic block diagram showing an electrical configuration of a microwave oven according to another embodiment of the present invention.

[Explanation of symbols]

1 Magnetron 2 Ferrite Ring 6 Noise Processing Section 7 Power Cord 8 Capacitor 9 Heater Lead Wires e _i , e _o Signals In the drawings, the same reference numerals indicate the same or corresponding portions.

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Claims (5)

(57) [Claims] 1. A noise output to a heater lead wire provided between a magnetron and a high-voltage transformer for converting a low voltage into a high voltage when the food is heated by radiating microwaves from the magnetron to the food. A noise processing device in a microwave heating cooker, wherein a signal for canceling a noise component that goes out from a power cord on the low-voltage side of the high-voltage transformer is applied to the power cord according to the component. Wherein said noise processing apparatus includes a detecting means for detecting the noise component at a predetermined position, reciprocal position of the noise component detected by said detecting means
And adjust the amplitude of the phase-inverted noise component.
The noise processing device in the microwave heating cooker according to claim 1, further comprising: a noise processing unit , wherein the noise component whose amplitude is adjusted by the amplitude adjusting unit is applied to the power cord. 3. The predetermined position for detecting the noise component by the detecting means is one of a position closest to a source of the noise component and a position immediately before the noise component is applied to the power cord. The noise processing device in the microwave heating cooker according to claim 2, wherein 4. A magnetron for radiating microwaves to the food to heat the food, a power cord connected to a power outlet, and a power cord provided between the power cord and the magnetron, A microwave heating cooker comprising: a high-voltage transformer for converting a voltage into a high voltage; and a heater lead wire provided between the high-voltage transformer and a heater of a magnetron, wherein the heater lead is provided when the magnetron is irradiated with microwaves. A noise processing device in a microwave heating cooker, wherein a signal for canceling a noise component that goes out through the power cord is applied to the power cord according to a noise component output to a line. 5. The microwave heating cooker according to claim 1, further comprising a noise filter provided between the power cord and the low-voltage side of the high-voltage transformer. Noise processing device.