KR940005470B1 - Over output protection apparatus of inveter microwave oven - Google Patents

Abstract

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Description

Over power protection device of inverter microwave oven

1 is a block diagram of an output control device of a conventional inverter microwave oven.

2 is a block diagram of the over-power protection device of the inverter microwave oven of the present invention.

3 is a detailed circuit diagram of the overpower protection device in FIG.

* Explanation of symbols for the main parts of the drawings

1 filter unit 2 rectifying unit

3: smoothing part 4: switching part

5: magnetron drive part 6; magnetron

7: synchronizer 8: oscillator

9: overvoltage protection unit 10: current control unit

11: output control unit 12: power control unit

13 switching driver 14 over-power protection device

CT ₁ : current transformer BD ₂₀₁ : bridge diode

OP ₁₀₁ : Operational Amplifier C ₂₀₁ : Condenser

R ₁₀₁ -R ₁₀₆ : Resistor D ₁₀₁ : Diode

Q ₁₀₁ : Transistor

The present invention relates to an output control in an inverter microwave oven, and in particular, a fixed state of a system may be generated due to an over-output. The inverter electronics detects this over-output state so that the output does not exceed a certain output in the over-output state. An over-power protection device for a range.

As shown in FIG. 1, an output control device of a conventional inverter microwave oven includes a filter unit 1 for removing noise of an AC power source AC input, and an AC power source through the filter unit 1 for direct current. Rectification section 2 for changing the current, the smoothing section 3 for directing the rectified pulse wave waveform by coil L ₁ and condenser C ₁ , transistor Q ₁ , and diode D _1. ) And a condenser (C ₂ ) consisting of a switching unit (4) for switching and outputting a high frequency, a high voltage transformer (L ₂ ) for changing the high frequency to be switched to a high voltage, a capacitor (C ₃ ) and a diode (D ₂ ) and (D ₃ ), the magnetron driving unit 5 for driving the magnetron 6 by doubling the high voltage from the high voltage transformer L ₂ , and the oscillation unit 8 at a certain point. Synchronization unit 7 for adjusting the oscillation of the oscillator to be repeated, and an overpower operated to maintain a constant output Protection unit (9), a current controller 10, which detects the anode current of the magnetron (6) to be output at a constant current, the transformer (L _3), the power control unit 12 to enter a powered-on control of the And an output control unit 11 for controlling and outputting an output signal for changing a frequency by the oscillator 8, the overvoltage protection unit 9, the current control unit 10, and the power control unit 12, and the output. It is composed of a switching driver 13 for turning on / off the operation of the transistor Q ₁ in the switching unit 4 by the output signal adjusted by the adjusting unit 11.

The conventional technical operation configured as described above rectifies and smoothes the AC power from which the noise is removed via the filter unit 1 from the rectifying unit 2 and the smoothing unit 3 to the switching unit 4 by the high voltage transformer L ₂ . Authorize.

Accordingly, the high voltage transformer L ₂ converts the switched AC waveform to high voltage and then is used as a half-wave voltage through the magnetron driver 5 to drive the magnetron 6.

At this time, the switching unit 4 is operated by the drive signal of the switching driver 13 to switch the high frequency, the switching driver 13 is based on the output control of the output control unit (11).

In addition, the output control unit 11 operates in conjunction with the oscillation unit 8, the overvoltage protection unit 9, the current control unit 10, and the power control unit 12 to oscillate in response to the synchronization signal from the synchronization unit 7 It is supposed to be.

However, such an output control device of a conventional inverter microwave oven may produce an excessive output when the output device is damaged due to a change in the characteristics of the power supply and a severe induction of the set. There was a disadvantage that the reliability of the set is not guaranteed because a fatal defect is applied to the life of the component.

In view of the above disadvantages, the present invention senses the input current when the input current is increased due to the over-output when operating at the over-output, thereby reducing the output by overloading the inverter microwave oven that can operate at normal or constant output. Invented an output protection device, which will be described below with reference to the accompanying drawings.

2 is a block diagram of the over-power protection device of the inverter microwave oven of the present invention, as shown therein, a filter unit 1 for removing conductive noise of an AC power source, a rectifying unit 2 for rectifying an AC power source, and A smoothing section 3 for directing the rectified pulse flow, a switching section 4 for causing high frequency switching, a high voltage transformer L ₂ for changing the high frequency into a high voltage, and a half wave of the high voltage. A magnetron driver 5 for driving the magnetron 6 by the half-wave voltage, a synchronizer 7 for outputting a synchronization signal so that oscillation can be repeated at a predetermined point, and the synchronizer 7 Oscillator 8 for changing the frequency by oscillating by the synchronous signal of, overvoltage protection unit 9 operated to maintain a constant output, and the anode current of the magnetron 6 is sensed to a constant current Keep the output A current control unit 10 operable to operate, a power control unit 12 for supplying and controlling input power through a transformer L ₃ , the oscillator 8, an overvoltage protection unit 9, a current control unit 10, The output control unit 11 for changing the frequency by the operation of the power supply control unit 12 and the switching element Q ₁ of the switching unit 4 by the output control unit 11 to turn on / off time In the inverter microwave oven composed of a switching driver 13 to adjust the output, by detecting the change of the input current changed to the excessive output by the current transformer (CT ₁ ) to lower the output the output control unit 11 constant output It is configured to include an over-power protection device 14 to operate in.

FIG. 3 is a detailed circuit diagram of the over-power protection device in FIG. 2, after rectifying the current sensed through the current transformer CT ₁ in the bridge diode BD ₂₀₁ , and then the capacitor C ₂₀₁ and the resistor ( R ₁₀₁ ), (R ₁₀₂ ) is input to the inverting terminal (-) of the operational amplifier (OP ₁₀₁ ) and the non-inverting terminal (+) by comparing the reference voltage by the resistor (R _103- R ₁₀₅ ) The output of the operational amplifier OP ₁₀₁ is configured to be input to the output control unit 11 by the transistor Q ₁₀₁ , the resistor R ₁₀₆ , and the diode D ₁₀₁ .

The operation and effects of the present invention configured as described above will be described with reference to FIGS. 2 and 3.

First, when AC power is inputted and rectified through the filter unit 1 for removing noise, the smoothing unit 3 transmits the rectified pulse wave waveform to the coil L ₁ and the capacitor C ₁ . DC by the high voltage transformer (L ₂ ) and then input to one side and the switching unit (4).

At this time, the transistor Q ₁ is switched to the switching unit 4 by the switching driver 13 to output a high frequency, and the high voltage transformer L ₂ changes the high frequency to a high voltage to the magnetron driver 5. To drive the magnetron 6.

That is, the switching driver 13 is driven by the output control of the output control unit 11, the output control unit 11 drives the oscillation unit 8 by the synchronization signal of the synchronization unit 7 to change the frequency In addition, the overvoltage protection unit 9 and the current control unit 10 operate to maintain a constant output and receive power from the power control unit 12.

On the other hand, when the excessive output is generated by the characteristic change and the flow of the set, the over output protection device 14 detects the input current generated due to the excessive output and operates to lower the output when the input current is higher than the set value. In detail, the current is sensed by the current transformer CT ₁ for detecting a change in the input current, and the sensed current is rectified by the rectifying bridge diode BD ₂₀₁ .

Then, the rectified pulsating current is changed to direct current by the capacitor (C ₂₀₁₎ resistance (R _101), there is a bias by (R _102), wherein the connection point of the resistor _{(R 101), (R 102} ) A When the potential of the point (V _A ) becomes higher than a certain value, it is compared with the potential (V _F ) of the point B. When the voltage _A becomes V _A > V _F by the compared potential, the output side potential (V) of the operational amplifier OP ₁₀₁ . _G ) is the ground level.

Accordingly, the transistor Q ₁₀₁ is turned on to operate the output control unit 11, which adjusts the potential of the output control unit 11 to lower the potential of the magnetron on time of the output control unit 11. To lower the output.

However, in general, since the potential V _{A at the} point _A is lower than the potential V _{F at the} point B, the output side potential V _G of the operational amplifier OP ₁₀₁ indicates a high level, thereby causing the transistor Q ₁₀₁ to become high. Turn off and do not affect the normal output.

As described in detail above, when the set is completed after adjusting the constant output in the inverter microwave oven, in the conventional case without the over-power protection device, the constant output may be changed due to the change in characteristics of the set and the severe impact. Higher outputs result in burnout of components due to higher outputs, which significantly reduces the reliability of the set.

Therefore, the present invention adds an over-power protection device to detect when a high output caused by the flow of the set or changes in characteristics to operate so as not to exceed a certain output, so that the user is safe and other defects until the life of the set There is an effect that can not be used without.

Claims (2)

Filter unit 1 for removing conductive noise of AC power, rectifying unit 2 and smoothing unit 3 for rectifying and smoothing AC power through the filter unit 1, and switching unit for switching high frequency (4), a high voltage transformer (L ₂ ) for changing the high frequency from the switching section (4) to a high voltage, and a magnetron driving unit for driving the magnetron (6) by the half wave voltage by halving the high voltage. (5), a synchronizing unit (7) for outputting a synchronizing signal to cause the oscillating unit (8) to change frequency, an overvoltage protection unit (9) operating to maintain a constant output, and a magnetron (6) A current control unit 10 for sensing an anode current and outputting a constant current, a power control unit 12 for supplying power, the oscillator 8, an overvoltage protection unit 9, a current control unit 10, and a power control unit Switching by changing the frequency of the switching driver 13 in accordance with the operation of (12) (4) the output control unit 11 for controlling the on / off time of the switching element in the over-current protection device for controlling the operation of the output control unit 11 by detecting a change in the input current that is changed to the excessive output 14. An over-power protection device for an inverter microwave oven, characterized by comprising (14). The method of claim 1, wherein the over-power protection device 14 detects the change in the input current by the current transformer (CT ₁ ) and then the detected current is bridge diode (BD ₂₀₁ ) and capacitor (C ₂₀₁ ) and capacitor Rectification and direct current by (C ₂₀₁ ), the bias voltage (V _A ) by the resistor (R ₁₀₁ ), (R ₁₀₂ ) is input to the inverting terminal (-) of the operational amplifier (OP ₁₀₁ ) and the non-inverting terminal Compared to the reference voltage (V _F ) input to the (+), characterized in that configured to drive the transistor (Q ₁₀₁ ) with the output voltage (V _G ) compared to adjust the output of the output control unit 11 Over output protection device for inverter microwave ovens.