JPH0617191U - High frequency heating device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To drive multiple magnetrons with a simple configuration. [Structure] A plurality of magnetrons 13a, 13b, a rectifying / smoothing circuit 20, an inverter circuit 30, a voltage doubler rectifying circuit 40, a pulse generating circuit 15, a primary winding 8, a high-voltage secondary winding 9, and a heater. A step-up transformer 7 having a secondary winding 10 is provided, and an anode 16a, 16b and a cathode 17a, 17 of each of the plurality of magnetrons 13a, 13b are provided.
b is connected in parallel to the voltage doubler rectifier circuit 40, and the filaments 18a and 18b of each of the plurality of magnetrons are connected in parallel to the heater secondary winding 10. Anodes 16a, 16b,
The same voltage is supplied between the cathodes 17a and 17b, and the heater secondary winding 10 supplies the same voltage to the filaments of the plurality of magnetrons, so that the plurality of magnetrons can obtain substantially the same high-frequency output.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-frequency heating device such as a microwave oven in which a magnetron is driven by an inverter power supply that generates a voltage of a frequency higher than a commercial frequency to cook.

[0002]

[Prior art]

 Many types of microwave ovens, which drive a magnetron with an inverter power supply, are currently on the market due to the advantages such as the weight of the power supply being significantly reduced and the high frequency output of the magnetron being variable.

There is also a strong demand for higher power for shortening the cooking time, and for this reason, proposals have been made to increase the high frequency output by using a plurality of magnetrons (eg Japanese Patent Publication No. 3-63198). (See the official gazette).

FIG. 3 is a diagram showing a conventional circuit configuration of a high frequency heating apparatus using a plurality of magnetrons. In the figure, parts using the same parts are shown with the same numbers a and b. In the following description, a and b will be omitted and only the numbers will be described.

In FIG. 3, a plurality of magnetrons 13 for supplying high-frequency radio waves, and the same number of these magnetrons 13 as in the conventional inverter power supply are wound with one primary winding 8 and one secondary winding 9 for boosting. Booster transformers 7, resonant capacitors 5 used in the same number as these booster transformers 7, a plurality of switching elements for driving a plurality of resonant circuits formed by the booster transformers 7 and the resonant capacitors 5 described above. 6 and an inverter power supply composed of components such as a switch 14 for selecting ON / OFF of these switching elements 6 are configured to be controlled by a single pulse generation circuit 15. The number of inverter power supplies is the same as the number of magnetrons 13 as mentioned above, though it has been made more compact and lighter and smaller. .

[0006]

[Problems to be solved by the device]

 The conventional high-frequency heating device described above requires multiple large components such as a step-up transformer, a switching element, and a high-voltage capacitor. Therefore, the power supply circuit is more difficult than a general high-frequency heating device that uses one magnetron. Therefore, there was a problem that the high-frequency heating device itself became large and the price became very high.

[0007]

[Means for Solving the Problems]

 The present invention has been made to solve the above problems, and includes a plurality of magnetrons, a rectifying / smoothing circuit, an inverter circuit, a voltage doubler rectifying circuit, a pulse generating circuit, and a primary winding connecting the inverter circuits. And a high voltage secondary winding for supplying high voltage power to the plurality of magnetrons through the voltage doubler rectifier circuit, and a heater secondary winding for supplying power to the filaments of the plurality of magnetrons. A step-up transformer is provided, the anodes and cathodes of the magnetrons are connected in parallel to the voltage doubler rectifying circuit, and the filaments of the magnetrons are connected in parallel to the heater secondary winding. It was configured.

[0008]

[Action]

 With the above configuration, the high voltage secondary winding of the step-up transformer supplies the same voltage between the anodes and cathodes of multiple magnetrons, and the heater secondary winding supplies the same voltage to the filaments of multiple magnetrons. As a result, the same high-frequency output can be obtained from each of the multiple magnetrons.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to FIG.

In the figure, the same parts as those of the conventional example are denoted by the same reference numerals, and the individual parts have the same functions and operations as those of the conventional example, and only some of the specifications are different.

A commercial power source 1 is connected to a rectifying / smoothing circuit 20 including a bridge diode 2, a smoothing choke coil 3, and a smoothing capacitor 4, and is converted into a DC power source. A resonance capacitor 5 forms an LC parallel resonance circuit with the primary winding 8 of the step-up transformer 7, and an inverter circuit 30 with a switching element 6 such as a power transistor. The rectifying / smoothing circuit 20 and the inverter circuit 30 are connected in parallel. Reference numeral 9 denotes a high voltage secondary winding, which is connected in parallel with a voltage doubler rectifier circuit 40 including an anode 16a and a cathode 17a of the magnetron 13a, an anode 16b and a cathode 17b of the magnetron 13b, a high voltage capacitor 11 and a high voltage diode 12. Has been done. Reference numeral 10 denotes a heater secondary winding, in which the filament 18a of the magnetron 13a and the filament 18b of the magnetron 13b are connected in parallel. A pulse generator circuit 15 is connected to the switching element 6 to control ON-OFF of the switching element 6 to control a high frequency current to the primary winding 8.

Next, the operation of this embodiment will be described.

The high voltage output from the high voltage secondary winding 9 of the step-up transformer 7 is supplied to the anodes 16a and 16b of the plurality of magnetrons 13a and 13b and the cathodes 17a and 17b via the voltage doubler rectifier circuit 40. The same voltage is applied between them. The voltage output from the heater secondary winding 10 is applied to the filaments 18a and 18b of the plurality of magnetrons 13a and 13b as the same voltage. As a result, the plurality of magnetrons 13a and 13b can obtain substantially the same high frequency output.

The high frequency output of the magnetrons 13a and 13b can be performed in the same manner as when controlling one magnetron by a method such as changing the duty of the ON-OFF of the switching element 6.

FIG. 2 shows another embodiment, which is the same as the above-mentioned embodiment except for the structure described below, in which the heater secondary winding 10 has a filament 18a of the magnetron 13a and a filament 18b of the magnetron 13b. Are connected in series, the same current flows through the filaments 18a and 18b, and the plurality of magnetrons 13a and 13b can obtain substantially the same high-frequency output.

[0016]

[Effect of device]

 As described above, according to the present invention, it is possible to drive a plurality of magnetrons with substantially the same component configuration as that of the inverter power supply that controls one magnetron. For this reason, the number of parts can be significantly reduced compared to the conventional example, and the mounting space for the inverter power supply can be smaller than in the conventional case. Therefore, it is possible to provide a high-frequency heating device that is inexpensive and has high space efficiency.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram of a high-frequency heating device showing an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram showing another embodiment of the same.

FIG. 3 is a schematic circuit diagram showing a conventional example.

[Explanation of symbols]

 6 Switching Element 7 Step-up Transformer 8 Primary Winding 9 High Voltage Secondary Winding 10 Heater Secondary Winding 11 High Voltage Capacitor 12 High Voltage Diode 13a, 13b Magnetron 15 Pulse Generation Circuit 16a, 16b Anode 17a, 17b Cathode 18a, 18b Filament 20 Rectification Smoothing circuit 30 Inverter circuit 40 times voltage rectifier circuit

Claims (2)

[Scope of utility model registration request] 1. A rectifying / smoothing circuit (20) for rectifying and smoothing a commercial AC power source, an inverter circuit (30) for converting a DC power source of the rectifying / smoothing circuit into a high frequency power source, and a pulse for controlling an operating frequency of the inverter circuit. Generator circuit (15)
A plurality of magnetrons (13a, 13b), a voltage doubler rectifier circuit (40) for supplying a high voltage DC power to the plurality of magnetrons, and a primary winding (8) connected to the inverter circuit. A step-up transformer (7) including a high-voltage secondary winding (9) connected to the voltage doubler rectifier circuit and a heater secondary winding (10) connected to the plurality of magnetron filaments (18a, 18b). In addition, the anodes (16a, 16b) and cathodes (17a, 17b) of the plurality of magnetrons are connected in parallel to the voltage doubler rectifier circuit, and the filaments (18a, 18a, 18
A high-frequency heating device characterized in that b) is connected in parallel to the heater secondary winding (10). 2. A rectifying / smoothing circuit (20) for rectifying and smoothing a commercial AC power source, an inverter circuit (30) for converting a DC power source of the rectifying / smoothing circuit into a high frequency power source, and a pulse for controlling an operating frequency of the inverter circuit. Generator circuit (15)
A plurality of magnetrons (13a, 13b), a voltage doubler rectifier circuit (40) for supplying a high voltage DC power to the plurality of magnetrons, and a primary winding (8) connected to the inverter circuit. A step-up transformer (7) including a high-voltage secondary winding (9) connected to the voltage doubler rectifier circuit and a heater secondary winding (10) connected to the plurality of magnetron filaments (18a, 18b). In addition, the anodes (16a, 16b) and cathodes (17a, 17b) of the plurality of magnetrons are connected in parallel to the voltage doubler rectifier circuit, and the filaments (18a, 18b) of the plurality of magnetrons are connected. Is connected in series to the heater secondary winding, and the high-frequency heating device is characterized in that.