JPH01296585A - High frequency heating device - Google Patents

Abstract

PURPOSE:To set the capacity of a high voltage capacitor, wherein temp. rise in a coil part is suppress and which suits well to the power supply frequency certainly, by using a high voltage relay with normally closed contact as a switching means to perform current supply control on one of the sides of the high voltage capacitor. CONSTITUTION:One side of a high voltage capacitor 7 to emit output of external power supply 12 directed to the 60Hz region is connected with one end of a high voltage transformer 6 on its high voltage output side. A high voltage resistance for discharging 18 is connected in parallel with this capacitor 7, and another high voltage capacitor 7b is connected in parallel with a high voltage capacitor 7a for 60Hz through a contact 19b of a high voltage changeover relay, wherein the contact 19b is formed from normally closed contacts. Energization/deenergization is conducted according to the frequency of the external power supply 12. This signal of energization/deenergization is generated by a power supply frequency judging means and control means 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-frequency heating device, and more particularly to a cooking appliance that can be used in regions with different power supply frequencies without changing parts.

Conventional technology In Japan, the power frequency is 60Hz and 60Hz.
There are areas with H7. To deal with this, the microwave oven is equipped with two high-voltage capacitors 52 and 53, as shown in Figure 11.
As a means for changing the capacity of the high-voltage capacitor, it is configured using an a-contact type high-voltage relay 54 and a discharge resistor 55.56. When the power supply frequency is 60 Hz, when the power supply frequency is turned on, the high-voltage relay is Coil part 54
When a voltage is applied to the terminal 54a to close the contact 54b, and the power clock via the low voltage transformer 3...-7 is not input to the control unit 58 for a predetermined period of time, the coil unit 54 of the high voltage relay
Stop applying voltage to a, open the contact 54, and discharge the electric charge charged in the high voltage capacitor 53 to the resistor 56.
Further, the electric charge charged in the high voltage capacitor 52 is discharged by the discharge resistor 55.

Furthermore, when the power supply frequency is 60Hz, the high voltage relay contact 54b is in the "open" state, and if no voltage is input via the high voltage transformer 59, the electric charge charged in the high voltage capacitor 52 is discharged by the discharge resistor 55. There is.

However, the problem to be solved by the invention is that the above system, that is, the high voltage capacitor 5
2.53.1a contact type high voltage relay 54, discharge resistor 55.
The method of dealing with a power supply frequency of 50.60H7 using a power supply frequency of 50Hz is extremely costly, and
In this case, after the power is turned on, the low voltage transformer 59
A voltage is applied to the high voltage relay coil section 54a until the power supply clock is no longer input to the control section 57,
There was a problem with the temperature rise in the coil section.

Means for Solving the Problems The high-frequency heating device of the present invention uses a 1B contact type high-voltage relay as a switch means for controlling energization to one side of the high-voltage capacitor, has only one high-voltage resistor for discharging, and has a double-checked predetermined voltage. #, energize the 1B contact type high voltage relay during frequency cooking, and energize the 1B contact type high voltage relay before energizing the high voltage transformer, and de-energize it after stopping the energization to the high voltage transformer. composition.

Function: The high-frequency heating device of the present invention uses a 1B contact type high-voltage relay as a switch means for controlling energization to one side of the high-voltage capacitor, so that only one high-voltage resistor for discharging can be used. In addition, the power supply frequency is determined twice: immediately after plug-in, and once after the user presses the cooking start key after cooking settings, and then the high-voltage relay is activated. This ensures that the capacity of the high-voltage capacitor is set to match the power supply frequency. 5
・・・－・ I can do it. In addition, the high voltage transformer is energized after the high voltage relay contacts are completely ``open'', and the high voltage relay contacts are ``closed'' after the high voltage transformer is de-energized, so no arc is generated. , high voltage relays can be switched safely. Furthermore, since the high voltage relay is operated for a period of time after the cooking start key is pressed until the cooking end or cancel key is input, it is possible to suppress the rise in temperature of the coil section.

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

FIG. 1 shows an external perspective view of a high-frequency heating device to which the present invention is applied.
A door 3 provided in the heating chamber 2 so as to be openable and closable allows food to be taken in and taken out of the heating chamber 2 and prevents leakage of high frequency energy. On the upper front surface of the cabinet 1, an operation panel 4 is provided with various switches, setting keys for heating mode, heating time, etc., a start key 48 for starting button cooking, etc. 6...-/.

FIG. 2 is a horizontal sectional view of the top of the cabinet 1, in which a magnetron 5 that generates high frequency energy, a high voltage transformer 6 and a high voltage capacitor 7 that apply a high voltage to the magnetron 5 are arranged. In addition, a control board 8 incorporating a microcomputer 22 (Fig. 3) having information for detecting the power frequency and controlling heating.
A cooling fan 9a1.10a rotationally driven by a motor 91.10 is provided to cool each of the circuit components. A part of the wind that cools the magnetron 5 by the cooling fan 10a is configured to be sent into the heating chamber 2 described above through the air duct 11.

FIG. 3 shows the basic configuration of the circuit of this high-frequency heating device. 6a, door switch 14, fuse 1
5 are connected in series.

Further, a door monitor switch 16 is connected in parallel to the power supply 12. In addition, the lamp relay contact 42b, the interior light 43 for heating indoor lighting, and the magnetron cooling fan 10,
A turntable motor 44 and the like are also connected in parallel.

A high voltage capacitor 7 is connected to the secondary coil 6b of the high voltage transformer 6.
The anode and cathode of the magnetron 5, which is a high-frequency wave generator, are connected through a half-wave voltage doubler circuit formed by a high-voltage diode 17 and a high-voltage diode 17. The anode of the magnetron 5 is grounded, and the heater (cathode) is connected to the secondary coil 6C of the high voltage transformer 6. The high-voltage capacitor 7 consists of two elements 7, 7b, connected in parallel, and a discharge resistor 18 is connected in parallel to these elements. Further, a contact 19 of a b-contact type high-voltage relay 19 is provided with a positive terminal in the middle of the electric path between the high-voltage capacitors 7a and 7b.

Further, a control unit 21 is connected to the power supply 12 via a fuse 15 and a low voltage transformer 20.

This control section 21 consists of a microcomputer 22 and its peripheral circuits, etc., and has an internal pulse generation circuit 23 according to the power frequency, and externally an operation section 24, a display section 25, and coil sections of relays 13, 19, and 42. 13a, 19a
, 42a are connected.

In addition, the microcomputer 22 (hereinafter referred to as microcomputer) is connected via approximately 1/b (input, output section) 228.
A PU (central information processing unit) 22b is coupled to it, and a RAM (a storage device that can read and write) 22C is connected to it.
and ROrNA (read-only storage device) 22d are combined.

Next, the operation will be explained using the configuration as shown in the following.

First, the determination of the power supply frequency will be described.

When AC power is turned on to this high frequency heating device, it passes through the pulse generating circuit 23 shown in FIG.
The 0 Hz power supply waveform 47a is shaped into a rectangular waveform 47b. Here, the period of waveform 47a is 2Q as shown in 47C.
It is m5ec. Further, as shown in FIG. 5, the 6QHz power supply waveform 60a is shaped into a rectangular waveform 9...-7 60b, and the period thereof is 16... as shown in 60C.
It is 7m5ec. For example, the microcomputer 22 is MB8851 manufactured by Fujitsu. When using an OB series microcontroller,
As shown in FIG. 3, the pulse generation circuit 23 is connected to the IRQ terminal. When the power supply 12 is input to the ROM section 22d of the microcomputer 22, after all clearing of the RAM section 22c and initial setting of each port, the power supply frequency determination program shown in FIG. 6 is configured. The case where the power supply frequency is 60 Hz will be described below. At step 26, the falling edge of IRQ is sensed (FIG. 4, 47g). Next step 2
7. Set so that an internal interrupt occurs after pm and see in 2B. Here, P is set to an intermediate value of 50.6QHz, that is, C(1/60)+(1150))/2. After P771 Sec, an internal interrupt shown in Figure 7 occurs, and the program in step 3B-39 is executed from the RAM2-der, and from Figure 4, at 47h, IRQ = "H".
”, RAM1=0010 is set at 40.

Returning again to the main routine in Figure 6, RAM2 is incremented, RAIVI2 = 1, goes to 10, and in step 32, senses the IRQ rise (
Fig. 4 471). The IRQ level after P77zsec is "Shi" from 47j in FIG. 4, so execute the program from step 38 to 45 in FIG.
The process returns to the main routine shown in FIG. 6. RAM
2 becomes 2, so execute step 41 and set RAM1=
1000, and the falling edge of IRQ is sensed again in step 26 (FIG. 4, 47k). Capturing Figure 4 471,
RAM1 is set to 1010, RAM2 is set to 3, and in step 32 the IRQ is sensed (4th
Figure 47m). Capturing 47h in Figure 4, RAM1=10
In the state of 10, step 3o is executed and the data is incremented in the RAM 2-4, and thus a total of 4 rounds of discrimination of the shaped waveform is completed. When the power supply frequency is 60 Hz, as can be seen from FIG. 5, RAM1=5 when a total of 14 determinations are completed.

Using RAM1, 34-37, 50 H2, R
Set AM3 to 1. Here, the process may return to the beginning of the main routine at 36, but this 1 1 , -; is when the same frequency is not judged four times in a row, and the loop continues until the same frequency is judged four times in a row. do.

Next, the operation of the b contact type high voltage relay 19 will be described. When the power is off, in all-off mode, and in cooking setting mode,
As shown in FIG. 8(b), the contact part 19b of the high voltage relay
is "closed". After selecting the menu key on the operation panel 4 and setting the cooking time, etc., press the cooking start key-49.
When inputting , the ROM section 2 of the microcomputer 22 shown in FIG.
Step 60-62- of the program set to 2d
Execute in the order of 64. Here, in step 62, it is confirmed whether the menu and cooking time are set correctly.
If it is not correct, the process moves to the next routine in step 63. After confirming that the door is closed in step 64, the determination of the power supply frequency shown in FIG. 6 is performed again in step 65. Next, in step 66, when the judgment result immediately after plugging into RAM 3 and the judgment result by Step Pro 5 are equal,
In step 67, the high voltage relay is driven, the output of the magnetron, etc. are controlled.

When the power supply frequency is 60H7, a voltage is applied from the control section to the coil section 19a of the high voltage relay, and the contact section 19b is "opened" as shown in FIG. 9(b). As a result, in the high voltage capacitor 7 in the drive section of the magnetron 5, the element 7a
Only (capacitance CI) is incorporated into the half-wave voltage doubler circuit. Therefore, the capacitance C1 is provided as a capacitance that is compatible with the power supply frequency (60H2) at this time. FIG. 10 shows a timing chart of the voltage applied to the coils of each relay. Here, 51 indicates that the high voltage relay contact portion 19b is completely
Set the time. This is to prevent arcing. At the end of cooking or when the cancel key 46 is operated manually, voltage is not applied to the high voltage relay coil section 19a until time S2 has elapsed until the main relay contact section 13b is completely "open" in order to prevent arcing. , and the contact 19b is "closed". Thereafter, the electric charge charged in the capacitor 7a is discharged by the discharge resistor R18. Also, when the power supply frequency is 50Hz (RAM313 1.-.

In case of (suspect), even during cooking, contact 1 of the high pressure relay
9b is "closed", and the high voltage capacitor 7 is the element 7a.
and element 7b (capacitor fic2) are connected in parallel and incorporated into a half-wave voltage doubler circuit, and the power supply frequency (5
c1+c2 is given as a capacitance compatible with 0H7). Even after the cooking is finished, the contact part 19b of the high voltage relay
Since the capacitors 7a and 7b are "closed", the charges charged in the capacitors 7a and 7b are discharged by the discharge resistor R18.

Effect of the invention According to the present invention, the following effects can be obtained.

By using a 1, 1b contact type high voltage relay, one high voltage resistor for discharging can be removed, resulting in a reduction in product cost.

2. Since the high-pressure relay operates only during cooking, it is possible to suppress the rise in temperature of the relay coil.

3. Relay durability can be maintained in relation to r2j.

4 When the lb contact type high voltage relay contact opens,
14 Heh - Perform after the main relay has closed once, and when closing,
By performing this after the main relay is "open," arcing will not occur and switching can be done safely.

5. The power supply frequency is determined twice: immediately after plug-in, and once when the cooking start key is pressed manually.Actual cooking starts only when the results match, so you can be sure that the high-voltage capacitor that matches the power supply frequency is selected. Capacity can be set.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of a high-frequency heating device applied to an embodiment of the present invention, Fig. 2 is a two-part horizontal sectional view of the same, Fig. 3 is a circuit diagram of the same, Figs. 4 and 5. are input waveform diagrams of the IRQ port, Figures 6 and 7 are flowcharts of the power frequency determination program, Figure 8 is a flowchart of the start key processing program, and Figure 9 is the operation of the high voltage relay. 10 is a timing chart of the coil section of the same high voltage relay, and FIG. 11 is a circuit diagram of a conventional example. 1... Cabinet 7, 2... Heating chamber, 3...
...Do15...-a, 4...Operation panel, 4a...Cooking start ghee, 4b...Cancel ghee, 5...Magnetron, 6... High voltage lance, 7... High voltage capacitor, 8... Control board, 9... Morph, 9
a... Cooling fan, 11... Air duct, 12.
・Commercial AC power supply, 13 ・Main relay, 13a・
...Main relay coil section, 13b... Main relay contact section, 20...Low pressure lance, 21...
...Control unit, 22...Microcomputer,
228...+10.22b-cpu, 22cm-
=RAM, 22CI ・-RAMi, 22C2...
...RAM2.22C3...RAM3.22
d...ROM, 23...Pulse generation circuit,
24... Operation unit, 25... Display unit.・Name of the agent: Patent attorney Toshio Nakao and 1 other person → Shichikari Kakiya 1 ・、J Shelf R Separately Locked Lock Terminal E

Claims (1)

[Claims] (1) A high-voltage circuit that includes a high-voltage transformer, a high-voltage diode, a high-voltage resistor for discharging, two high-voltage capacitors, a high-voltage switching relay, etc., a high-frequency generator connected to an external power supply via this high-voltage circuit, and a heated object. a heating chamber in which the heating chamber is placed, a door provided at the front of the heating chamber, an input means for inputting cooking data consisting of functional information, numerical information, etc., means for determining a power supply frequency, and the high frequency generator. one of the high voltage capacitors capable of obtaining an output for a 60 Hz region is connected to one end of the high voltage output side of the high voltage transformer, and the high voltage capacitor is connected in parallel to the high voltage capacitor for 60 Hz. The high voltage resistor for discharging is connected to the high voltage resistor, and the other high voltage capacitor is connected to the high voltage capacitor for 60Hz in parallel through the contact of the high voltage switching relay, and the contact of the high voltage switching relay is normally closed. 1. A high-frequency heating device comprising contacts, energized and de-energized according to the frequency of an external power source, and signals for energizing and de-energizing being entrusted to the power source frequency determination means and the control means.