JPH03241691A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To control an inverter circuit with a small-sized and inexpensive switch by turning on or off the oscillator switch for feeding power to an oscillator driving the semiconductor switching element of the inverter circuit. CONSTITUTION:An inverter power source 3 converts the DC low voltage obtained from a DC power source 1 to the DC high voltage and AC high voltage and excites a magnetron 4. The magnetron 4 generates microwaves, and microwaves heat an object to be heated such as food. An inverter circuit 3 is switched by the signal from an oscillator 6 applied to a semiconductor switching element 5 and generates the DC high voltage and AC high voltage. The oscillator 6 is fed with power from a DC power source 1 via a door switch 7 turned on or off by the opening/closing of a door for storing the object to be heated in a high-frequency heating device, an oscillator switch 8 and a cutoff means 2.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a so-called microwave oven that uses microwaves to heat and cook food, etc. In particular, the present invention relates to a so-called microwave oven that uses microwaves to heat and cook food. This invention relates to a high-frequency heating device that obtains electric power.

Conventional technology The conventional technology will be explained below with reference to the drawings.

FIG. 3 is a circuit diagram showing the configuration of a conventional high-frequency heating device. In the figure, an inverter circuit 3 receives power from a low-voltage DC power source 1 such as a 12-volt or 24-volt battery mounted in a car or the like. The DC power supply 1 and the inverter circuit 3 include a cutoff means 2, such as a fuse, that cuts off when an overcurrent flows, and a door switch 18 that turns on and off by opening and closing the door for housing the object to be heated in the high-frequency heating device. It is connected to the inverter power supply 3 via the inverter circuit switch 19 and the inverter circuit switch 19 . The inverter power supply 3 converts the DC low voltage obtained from the DC power supply 3 into a DC high voltage and an AC voltage, and energizes the magnetron 4 . The magnetron 4 generates microwaves, which are guided into the heating chamber of the high-frequency heating device and heat an object to be heated, such as food, stored in the heating chamber.

The inverter circuit 3 has a semiconductor switching element 5, and the oscillator 6 drives this semiconductor switching element 5.

The input means 9 is a means for inputting information such as operation, stop, and operation time of the high-frequency heating device, and the information from the input means 9 is transmitted to the control circuit 10.

The control circuit 10 controls the oscillator 6 based on information from the input means 9. Power is supplied to the oscillator 6 and the control circuit 1o from the DC power supply 1 via the cutoff means 2, the door switch I8, and the inverter circuit switch 19.

The door switch 18 is used to operate the in-hark circuit 3 with the door open and to prevent microwaves from being radiated outside the heating chamber.

The door is closed, that is, the door switch 18 is turned on,
Moreover, when the inverter switch 19 is turned on, a DC voltage is applied to the inverter circuit 3, and at the same time, the control circuit 1
0, since power is supplied to the oscillator 6, the control circuit 10 operates, controls the oscillator 6 based on information from the input means 9, and operates the inverter circuit 3. The inverter circuit 3 converts the DC low voltage into a DC high voltage and an AC voltage, outputs the converted voltage, and energizes the magnetron 4.

Problems to be Solved by the Invention Below, the problems to be solved by the present invention will be explained with partial reference to FIG. 3, which is a circuit diagram showing the configuration of a conventional high-frequency heating device.

To heat the object stored in the heating chamber of a high-frequency heating device, for example 0.2 liters of water, from 20°C to 80°C,
Approximately 500 watts of power is required to perform the process in about minutes. Since the efficiency of a high frequency heating device is approximately 50%, an input of 1000 watts is required to the high frequency heating device. When a 12 volt or 24 volt battery installed in a car or the like is used as a power source for supplying power to the inverter circuit 3 of the high frequency heating device, the current is 84 volts.
A large current of ampere or 42 amperes must flow. Therefore, the door switch 1B, which is a relay switch or the like, is turned on and off by opening and closing the door, and the inverter circuit switch 19 is used to operate and stop the inverter circuit.
required the use of large, expensive relay switches with large contact capacity.

Furthermore, since the inverter circuit ra3 has a capacitor 20 with a large capacity, a large inrush current flows at the moment the door switch 1B or the impark circuit switch 19 is turned on, causing the relay switch to burn out. In order to prevent this, a relay switch with a sufficiently large contact capacity must be used as the door switch 18 or the inverter circuit switch 19. Therefore, there was a problem that the relay switch became large and expensive.

Means for Solving the Problems The present invention has been made to solve the problems described above, and is based on the following means.

First, a DC power source such as a battery, an inverter power source that receives power from the DC power source, an oscillator that drives a semiconductor switching element of the inverter power source, a control circuit that controls the oscillator, and a power supply to the oscillator. on/off
an oscillator switch that is turned off; and a switch operating means that turns on and off the oscillator switch according to a signal from the control circuit; The configuration is configured to control the inverter circuit.

Second, a door switch is provided that is turned on and off by opening and closing the door that takes the object to be heated in and out of the heating chamber, and the power supply to the oscillator is turned on and off by turning on and off the door switch.

Thirdly, a detection means for detecting whether the l'' switch is turned on or off is provided, and a signal from this detection means is transmitted to the control circuit.

Fourth, there is a cutoff means that detects overcurrent and cuts off the power necessary for the control circuit, a door switch that turns on and off when the door is opened and closed, and an oscillator switch that turns on and off the power supply to the oscillator. The configuration is such that they are connected in series and connected to a DC power source to receive power supply.

action According to the present invention, the following effects are achieved.

First, a DC power source such as a battery, an inverter power source that receives power from the DC power source, an oscillator for driving a semiconductor switching element of the inverter power source, a control circuit for controlling the oscillator, and a control circuit for controlling the oscillator. An oscillator switch for supplying power to the oscillator, comprising an oscillator switch for supplying power to the oscillator, and switch operation means for turning on and off the oscillator switch according to a signal from the control circuit. By controlling the inverter circuit by turning on and off the oscillator, the power required for the oscillator is as small as about 3 watts. The switch can be made small and inexpensive with a small contact capacity and a raceway. Further, since no large inrush current flows through the oscillator at the moment the oscillator switch is turned on, it is possible to provide a small and inexpensive relay switch with a small contact capacity.

Second, a door switch is provided that is turned on and off by opening and closing the door for taking the heated object in and out of the heating chamber, and the power supply to the oscillator is turned on and off by turning on and off the door switch. By doing so, as described above, the power required for the oscillator is very small, so the door switch can be a small and inexpensive relay switch with a small contact capacity.

Thirdly, by providing a detection means for detecting whether the door switch is on or off, and transmitting a signal from the detection means to the control circuit, for example, when the door is open, the information can be transmitted. The information is transmitted to the control circuit, and the control circuit can turn off the oscillator switch via the switch operation means, so that the power supply to the oscillator can be cut off and the operation of the inverter circuit can be stopped.

Fourth, a cutoff means detects an overcurrent and cuts off the power necessary for the oscillator, a door switch turns on and off when the door is opened and closed, and detects the on/off state of the door switch and transmits the information. a detection means for transmitting information to the control circuit;
and an oscillator switch for turning on and off power supply to the oscillator, and in order to supply power to the oscillator, the cutoff means, the door switch, and the oscillator switch are connected in series, and the DC power source By connecting to the circuit and receiving power supply, the detection means gives information to the control circuit that the door is closed even though the door is open for some reason, and the control circuit Even if the oscillator issues an operation signal to the oscillator, since the door switch that supplies power to the oscillator is off, power is not supplied and the oscillator does not operate, so it is safe.

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

This figure is a circuit diagram showing the configuration of a high-frequency heating device according to an embodiment of the present invention, in which a low-voltage DC power source 1 such as a battery is connected to a cut-off means 2 that cuts off when an overcurrent flows, such as a fuse. and is connected to the inverter power supply 3. The inverter power supply 3 converts the DC low voltage obtained from the DC power supply 3 into a DC high voltage and an AC high voltage, and energizes the magnetron 4 .

The magnetron 4 generates microwaves, which are guided into the heating chamber of the high-frequency heating device and heat an object to be heated, such as food, stored in the heating chamber.

The inverter power supply 3 uses a semiconductor switching element 5 such as a transistor, and this semiconductor switching element is driven by an oscillator 6. The oscillator 6 is connected to the DC power supply 1 through a door switch 7, which is turned on and off by opening and closing a door for housing an object to be heated in the high-frequency heating device, an oscillator switch 8, and a cutoff means 2, and receives power supply therefrom.

The input means 9 is a means for inputting information such as operation, stop, and operation time of the high-frequency heating device, and the information from the input means 9 is transmitted to the control circuit 10.

The control circuit 10 controls the oscillator 6 based on information from the input means 9.
It controls the operation, stopping, intermittent operation, continuous operation, etc. of the controller, and also transmits information on the operating state to the display means 11.

The display means 11 displays the operating state based on information from the control circuit 10.

The control circuit 10 is connected to the DC power supply 1 via the control circuit switch 12 and the cutoff means 2 to receive power supply.

When the control circuit switch 12 is turned on and power is supplied, the control circuit 10 starts operating. The control circuit 10 controls the oscillator 6 based on the information from the input means 9. When the door of the high-frequency heating device is open, the control circuit 10 controls the on/off state of the switch provided in the door switch 7, that is, the on-off state of the high-frequency heating device. Based on the information from the detection means 13 that detects the open/closed state of the door, control is performed to stop the operation of the oscillator 6, and the oscillator switch for supplying power to the oscillator is turned off via the switch operation means 14 to turn off the power. Cut off the supply.

Even if for some reason a signal to turn on the oscillator switch 8 is given from the control circuit 10 to the switch operating means 14 even though the door is open, the door switch 7 and the oscillator switch 8 are connected in series. and door switch 7
is off, no power is supplied and the oscillator 6 does not operate. Therefore, since the inverter circuit does not operate, no microwaves are generated and it is safe.

The control circuit switch 12, the door switch 7, and the oscillator switch 8, which are switches for transmitting power to the control circuit 10 and the oscillator 6, are such that the power required for the control circuit 10 and the oscillator 6 is 1 watt and 1 watt. Since the power consumption is as low as 3 watts, a very small device can be used.

The inverter circuit 3 is switched by a signal from the oscillator 6 applied to the semiconductor switching element 5, generates a high DC voltage and an AC voltage, and energizes the magnetron.

Therefore, the operation of the inverter circuit is performed by opening and closing the control circuit switch 12 for supplying power to the control circuit IO. For some reason, the semiconductor switching element 5
If a signal continues to be applied to and an overcurrent flows, the interrupting means 2
Since the power supply to the inverter circuit 3 is cut off, fires caused by overheating can be prevented.

FIG. 2 is an external perspective view showing the configuration of a high-frequency heating device according to an embodiment of the present invention. In the figure, a control circuit switch 12, input means 9, and display means 11 are provided on the front of the high-frequency heating device, making them easy to operate and see.

By turning on and off the control circuit switch 12, the high-frequency heating device can be operated and stopped. The door switch 7 is installed to be turned on and off by opening and closing a second door 15 for storing a heated object 17 in a heating chamber 16.

Effect of the invention According to the present invention, the following effects are achieved.

First, by turning on and off the oscillator switch that supplies power to the oscillator that drives the semiconductor switching elements of the impark circuit, it is possible to control the inverter circuit with a very small and inexpensive switch. can.

Second, a door switch is provided that is turned on and off by opening and closing the door for taking the heated object in and out of the heating chamber, and the power supply to the oscillator is turned on and off by turning on and off the door switch. By doing so, the door switch can be made into a very small and inexpensive switch.

Thirdly, by providing a detection means for detecting whether the door switch is on or off and transmitting the signal from this detection means to the control circuit, the oscillator can be activated or stopped in accordance with the opening and closing of the door. When the heating chamber is open, the inverter circuit operates, eliminating the risk of microwave radiation outside the heating chamber and improving safety.

Fourth, a cutoff means detects an overcurrent and cuts off the power necessary for the control circuit, the door switch turns on and off when the door is opened and closed, and the power supply to the oscillator is turned on and off.
in series with the oscillator switch that is to be turned off;
By connecting to the DC power supply and receiving power supply, the control circuit is provided with information that the door is closed even though the door is open for some reason, and the control circuit Even if the control circuit issues an operating signal to the oscillator, the door switch that supplies power to the oscillator is off, so power is not supplied and the oscillator does not operate, so it is safe.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a high frequency heating device according to an embodiment of the present invention,
FIG. 2 is an external perspective view of the device, and FIG. 3 is a circuit diagram of a conventional high-frequency heating device. 1... DC power supply, 2... Cutting off means, 3
... Inverter circuit, 4 ... Magnetron, 5 ... Semiconductor switching element, 6 ...
...Oscillator, 7...Door switch, 8...
. . . Oscillator switch, 10 . . . Control circuit, 13 . . . Detection means, 14 . . . Switch operation means.

Claims (4)

[Claims] (1) a direct current power source obtained by rectifying alternating current obtained from a battery or a generator, an inverter power source that converts the direct current power into high frequency alternating current, an oscillator that drives a semiconductor switching element of the inverter power source; A control circuit for controlling an oscillator, a magnetron energized by the output of the inverter power supply, a heating chamber for storing an object to be heated such as food which is heated by irradiating the object with microwaves, and a heating chamber for storing an object to be heated such as food, The device includes an oscillator switch that supplies power, and a switch operating means that turns on and off the oscillator switch according to a signal from the control circuit, and controls the inverter circuit by turning on and off the oscillator switch. High frequency heating device. (2) A door switch is provided that is turned on and off by opening and closing the door that takes the heated object in and out of the heating chamber, and turning the door switch on and off turns on and off the power supply to the oscillator.
The high frequency heating device according to claim 1, which is turned off. (3) The high-frequency heating device according to claim 2, further comprising a detection means for detecting whether a door switch is turned on or off, and a signal from the detection means is transmitted to a control circuit. (4) A cutoff means that detects overcurrent and cuts off the power necessary for the control circuit, a door switch that turns on and off when the door is opened and closed, and an oscillator switch that turns on and off the power supply to the oscillator. The high-frequency heating device according to claim 3, wherein the high-frequency heating device is connected in series to a DC power source to receive power supply.