KR0143145B1 - Power control device of microwave oven - Google Patents

Abstract

The present invention relates to a microwave oven output control device and method for adjusting the magnitude of the total output energy by differentially controlling the magnitude of the voltage applied to the magnetron according to the selected function. The output control device of the present invention is a transformer (HVT) having a secondary winding for boosting the input AC voltage to a predetermined magnitude, and a capacitor (HVC) for backing up and rectifying the AC voltage boosted by the transformer (HVT). And a magnetron (MGT) driven by a diode (HVD) and the back pressure rectified voltage to generate a high frequency electromagnetic wave, the microwave oven for heating food, every predetermined number of turns of the secondary winding of the transformer (HVT) Calculate the size and driving time of the voltage to be supplied to the magnetron (MGT) according to the plurality of relay switches (RY3-RY5, RYn) and the selected heating or cooking function respectively connected to a plurality of voltage division terminals provided in the And a control unit 40 'that controls the switch means corresponding to the magnitude of the calculated voltage to be switched to the closed position during the calculated driving time.

Description

Microwave output control device and method

1 is an electric circuit diagram of a conventional microwave oven,

FIG. 2 is a timing diagram for explaining the output control method by the circuit shown in FIG.

3 is a circuit diagram showing a configuration according to an example of the output control device of the microwave oven of the present invention,

4 is a block diagram showing the configuration of the control unit shown in FIG.

FIG. 5 is a timing diagram for explaining the output adjustment method by the circuit shown in FIG.

6 is a flowchart showing a method of adjusting the output of a microwave oven according to the present invention.

* Explanation of symbols for main parts of the drawings

10: noise filter unit 20: low pressure unit

30,30 ': High pressure part 40,40': Control part

41 ': microprocessor 42': constant voltage generator

43 ': Function selector 44': Display and alarm

45 ': Door open detection part 46': Relay drive part

47 ': Load drive part RY1-RY6, RYn: Relay switch

The present invention relates to an output control device and method of the microwave oven, and more particularly to the output control device and method of the microwave oven to adjust the magnitude of the total output energy by differentially controlling the magnitude of the voltage applied to the magnetron according to the selected function. It is about.

As is well known, a microwave oven is a device for heating and cooking food by frictional heat generated in the process of vibrating water molecules contained in the food by high frequency electromagnetic waves.

FIG. 1 is an electric circuit diagram of a conventional microwave oven, and FIG. 2 is a timing diagram for explaining an output regulation method by the circuit shown in FIG. As shown in FIG. 1, the electric circuit of the conventional microwave oven is largely driven by the noise filter unit 10 and the input alternating current AC for removing noise components contained in the input alternating current AC. Low pressure unit 20 including all electrical components, high voltage unit 30 including a component for driving the magnetron (MGT) and the magnetron (MGT) for generating high-frequency electromagnetic waves and a control unit for controlling the operation of each part 40.

In the above configuration, the high voltage unit 30 is a magnetron (MGT), a kind of electron tube, a high voltage transformer (HVT) for boosting the input AC voltage to a predetermined size, the AC voltage boosted by the high voltage transformer (HVT) It consists of a high-pressure capacitor (HVC) and a high-pressure diode (HVD) to be applied to the cathode of the magnetron (MGT) back pressure and rectification. The high voltage transformer (HVT) is also provided with a winding for pressure reduction for supplying a large current to heat the heater of the magnetron (MGT). In the above-described configuration, when the user selects the normal cooking function, the control unit 40 switches the relay switches RY1 and bridge 2 to the closed position to supply a large current to the heater of the magnetron MGT and to heat the cathode. Apply a high voltage to the Accordingly, the electrons are emitted from the cathode of the magnetron MTG and the food is heated by continuously outputting a predetermined high frequency, for example, 2450 MHz, for a predetermined time due to the internal resonance structure. On the other hand, when the user selects the thawing function, the control unit 40 opens and closes the relay switch RY2 in a predetermined time pattern as shown in FIG. 2 and supplies the electric energy (power X time) supplied to the magnetron MTG. For example, it is reduced to 50% of the electrical energy of normal cooking. In other words, when the thawing function is selected, the conventional microwave oven operates the magnetron (MGT) for 10 seconds while maintaining the applied voltage at that of normal cooking, and operates the magnetron (MGT) for 10 seconds. By repeating the pattern, the total output is reduced to 50%. As a result, in a conventional microwave oven, it was possible to supply a certain amount of power intermittently, but it was impossible to continuously supply power by changing the size of the power itself. Accordingly, even though the thawing function was selected, the food was partially cooked. There was a problem.

The present invention is to solve the above problems, to provide an output control device and method for a microwave oven to adjust the magnitude of the total output by differentially controlling the voltage itself applied to the magnetron according to the selected function. There is this.

An output control device of the microwave oven of the present invention for achieving the above object is a transformer having a secondary winding for boosting the input alternating voltage to a predetermined magnitude, a capacitor for back pressure and rectifying the AC voltage boosted by the transformer; In a microwave oven for heating food having a diode and a magnetron driven by the back voltage rectified voltage to generate high frequency electromagnetic waves, a plurality of voltage division terminals provided for every predetermined number of turns of the secondary winding of the transformer. The magnitude of the voltage to be supplied to the magnetron and the driving time are calculated according to the plurality of switch means connected to each other and the selected heating or cooking function, and the switch means corresponding to the magnitude of the calculated voltage during the calculated driving time is closed. It characterized in that it comprises a control unit for controlling to switch to.

On the other hand, the output control method of the microwave oven of the present invention in the microwave oven that can adjust the magnitude of the voltage supplied to the magnetron for generating high-frequency electromagnetic waves in multiple stages, the process of receiving a selected heating or cooking function, and the selected heating And a process of calculating an output level and a driving time of the magnetron corresponding to a cooking function, and operating the magnetron by continuously applying a voltage corresponding to the calculated output level during the calculated driving time. In the above output control method, the output level and the driving time according to the selected function may be divided into multiple stages.

Hereinafter, with reference to the accompanying drawings, the configuration according to a preferred embodiment of the present invention will be described in detail.

3 is a circuit diagram showing a configuration according to an example of the output control apparatus of the microwave oven according to the present invention, and FIG. 4 is a block diagram showing the configuration of the controller shown in FIG. 3, and the same reference numerals are given to the same parts as in FIG. Doing. As shown in FIG. 3 and FIG. 4, the configuration according to an example of the output control device of the present invention is largely the noise filter unit 10 for removing noise components contained in the input AC power supply AC, input AC The high voltage unit 30 including the low voltage unit 20 including all the electric components driven by the power source AC, the magnetron MTG generating high frequency electromagnetic waves and the components for driving the magnetron MTG at a multi-level voltage. ') And a control unit 40' for controlling the operation of each unit.

The noise filter unit 10 includes the choke coils L1 and L2 and the choke coils having one terminal connected to both terminals of the capacitor C1 connected to both terminals of the input AC power supply and the capacitor C1, respectively. Condensers C2 and C3 are inserted in series between the other terminals of the fields L1 and L2. The other terminals of the capacitors C2 and C3 are grounded, respectively.

The low pressure unit 20 is a cooling fan motor that cools the lamp L, the rotating plate driving motor T / M, and the heat generating parts at both terminals of the AC power source AC passing through the noise filter unit 10. (F / M) is connected in parallel, in addition to a number of switches are placed in place. Looking at the switches, the first to third switches (SW1-SW3), the magnetron (MGT) to open or close according to the opening and closing of the door (not shown) to block the oscillation of the magnetron (MGT) when the door is opened. And an overheat cutoff switch (TS1; TS2) which cuts off the entire operation of the microwave oven in the event of an abnormal rise in the heating chamber temperature (TS1; TS2), a relay switch (RY1; And a relay switch RY2 (hereinafter referred to as a power switch) inserted into the front end of the primary winding of the high voltage transformer HVT. One terminal of the first and second switches SW1 and SW2 is connected to the rear ends of both terminals of the interior lamp L, respectively, and the third switch SW3 is connected between the other terminals of the first and second switches SW1 and SW2. ) Is connected. The motors T / M; F / M are connected in parallel to the rear end of the third switch SW3. In the above configuration, the first and second switches SW1 and SW2 are opened and closed in response to the opening and closing of the door, and the third switch SW3 is a circuit when the first and second switches SW1 and SW2 are closed. The door is opened and closed in response to opening and closing of the door to short-circuit.

The high voltage unit 30 ′ is a magnetron (MGT), a high voltage transformer (HVT) having a plurality of intermediate taps drawn from arbitrary turns of secondary windings, and a plurality of relay switches (RY3) connected to the respective intermediate taps. And a high voltage capacitor (HVC) and a high voltage diode (HVD) for applying back pressure and rectification to the cathode of the magnetron (MGT) by back pressure and rectifying the voltage boosted by the -RY5, RYn) and the high voltage transformer (HVT). The secondary side of the high voltage transformer (HVT) is also provided with a decompression winding for supplying a large current to heat the heater of the magnetron (MGT).

The controller 40 'is composed of various electronic components operated by a DC voltage, including a microprocessor 41' that controls the overall operation of the circuit. The electronic component generates a constant voltage to generate a constant DC voltage. Section 42 ', a function selecting section 43' for setting a cooking time and selecting a desired heating function, and controlling the above-described motors T / M and F / M under the control of the microprocessor 41 '. A load driver 47 'for driving various components, a relay driver 46' for driving various relay switches RY1-RY5, RYn, a door opening / closing detector 45 'for detecting whether a door is opened or closed, and A display alarm unit 44 'is provided to display the operation state of the microwave oven and to warn it of abnormal operation. In the third door, reference numeral F denotes a fuse and LVT denotes a decompression transformer, and the secondary winding of the decompression transformer LVT is connected to the constant voltage generator 42 'of the controller 40'.

Hereinafter will be described in detail with respect to the effect according to the preferred embodiment of the present invention. FIG. 5 is a timing diagram for explaining the output adjustment method by the circuit shown in FIG. 3, and FIG. 6 is a flowchart showing the output adjustment method of the microwave oven according to the present invention.

First, when the user puts food to be heated or cooked in the cooking chamber and closes the door, the first and second switches SW1 and SW2 are closed by the action of the door latch (not shown), while the third switch is closed. SW3 is open. Further, the microprocessor 41 'confirms that the door is closed through the door open / close detection unit 45' and outputs a control signal to the relay driver 46 'to close the power switch RY1, while the power switch ( RY2) continues to open. In this state, when the user selects the desired heating cooking function through the function selection unit 43 ', the microprocessor 41' receives it in step S100. Next, in step S102, the microprocessor 41 ′ calculates an output level and a driving time of the magnetron MTG corresponding to the function selected in step S100. The output level and the driving time calculated in this step (S102) may be a pattern which continues the same output until the end of heating cooking, and after heating cooking for a certain time at one level of output, it is optionally output to other levels. It may be a pattern for heating cooking for a time. For example, when the cooking function is selected, the selected function may be performed for a predetermined time while driving the magnetron (MGT) at the maximum output continuously. When the thawing function is selected, as shown in FIG. The selected function can be performed for a predetermined time at a level of 50% of the maximum output, and when a cooking function is selected, the learning step is performed for a predetermined time at the maximum output, and then for any time at a level of 70% of the maximum output. Moxibustion may be performed. In step S104, the microprocessor 41 'operates the timer t to check the driving time of the magnetron MTG.

In step S106, the magnetron MTG is driven to the calculated output level. That is, the microprocessor 41 'outputs a control signal to the relay driver 46' to close one of the relay switches RY3-RY5 and RYn and open the other. Accordingly, the voltage corresponding to the calculated output level is back-pressure rectified and applied to the magnetron MGT.

In step S108, the microprocessor 41 ′ determines whether the calculated driving time has elapsed. In step S108, when the calculated driving time has not elapsed, steps S106 and S108 are repeatedly performed, and when the calculated driving time elapses, the process proceeds to step S110, where the magnetron is operated at a different output level. MGT) to determine whether to drive. If it is necessary to drive the magnetron (MGT) to another output level at step S110, the magnetron (MGT) is further driven by repeating the above-described steps (S106, S108) for the calculated driving time. That is, the microprocessor 41 'outputs a control signal to the relay driver 46' to close the other one of the relay switches RY3-RY5 and RYn and open the other. Accordingly, the voltage corresponding to the other output level is back-pressure rectified and applied to the magnetron MGT. If it is not necessary to drive the magnetron (NGT) to another output in step S110 the heating cooking is terminated. In the above-described output adjustment method, the driving signal may be given as a set value by the user.

As described above, according to the output control apparatus and method of the microwave oven of the present invention, the magnetron is continuously driven by adjusting the size of the applied voltage itself, so that the food is partially ripened and the nutrients are destroyed when the thawing function is performed. The phenomenon is eliminated, and uniform and stable heating is induced when performing the cooking function, thereby improving the taste of rice.

Claims (4)

A transformer (HVT) having a secondary winding for boosting the input AC voltage to a predetermined magnitude, a capacitor (HVC) and a diode (HVD) for backing up and rectifying the AC voltage boosted by the transformer (HVT), and In a microwave oven for heating food having a magnetron (MGT) that is driven by the back-pressure rectified voltage to generate high-frequency electromagnetic waves, a plurality of voltages provided for each predetermined number of turns of the secondary winding of the transformer (HVT) The voltage and the driving time of the voltage to be supplied to the magnetron MTG are calculated according to the plurality of switch means RY3-RY5 and RYn respectively connected to the split terminals, and the driving time is calculated during the calculated driving time. And a control unit (40 ') for controlling the switch means corresponding to the magnitude of the calculated voltage to be switched to the closed position. 2. An output control apparatus for a microwave oven according to claim 1, wherein said switch means (RY3-RY5, RYn) are relay switches. A microwave oven capable of adjusting the magnitude of a voltage supplied to a magnetron (MGT) for generating high frequency electromagnetic waves in multiple stages, the method comprising: receiving a selected heating or cooking function; Computing an output level and a driving time of the magnetron (MGT) corresponding to the selected heating cooking function and continuously applying a voltage corresponding to the calculated output level during the calculated driving time to drive the magnetron (MGT) Output control method of a microwave oven, characterized in that it comprises a process. The method according to claim 3, wherein the output level and the driving time can be divided into multiple stages according to the selected heating cooking function.