KR20050033374A - A relay control method of microwave oven - Google Patents

Abstract

A method for controlling relays of microwave ovens is provided to suppress an inrush current by sequentially operating relays for controlling a high power commercial microwave oven. A microwave oven includes a magnetron(140) for generating microwaves, a microcontroller(130) for controlling the magnetron(140), and first and second relays(100,110). The first and second relays(100,110) are switched to supply a source voltage to the microcontroller(130). When the source voltage is applied, the first relay(100) is turned on. Whether the turn-on time of the first relay(100) exceeds a predetermined time interval is determined. When the turn-on time of the first relay(100) exceeds the predetermined time interval, the second relay(110) is turned on.

Description

A relay control method of microwave oven

The present invention relates to a microwave oven, and more particularly, to a relay control method of a microwave oven for preventing inrush current applied in a circuit.

Looking at the relay method of the microwave oven according to the prior art as follows.

1 is a relay circuit of a microwave oven according to the prior art.

First, referring to the connection relationship of the circuit, the power supply terminal 50 is connected to the microcontroller 60. The microcontroller 60 is connected to the first power relay 10 and the second power relay 20. The first and second power relays 10 and 20 are connected to the magnetron 70. Accordingly, when the first and second power relays 10 and 20 are turned on, the driving signal of the microcontroller 60 is transmitted to the magnetron 70, and the magnetron 70 is driven.

On the other hand, between the microcontroller 60 and the first power relay 10, the first inrush relay 30 for preventing inrush current applied in the circuit by the on operation of the first power relay 10. ) Is connected. In addition, between the microcontroller 60 and the second power relay 20, a second inrush relay 40 for preventing inrush current applied in the circuit by the on operation of the second power relay 20 is provided. Connected.

In addition, a first current limiting resistor R1 is provided between the first power relay 10 and the first inrush relay 30 to limit the current. A second current limiting resistor R2 is provided between the second power relay 20 and the second inrush relay 40 to limit the current.

Looking at the operation control process connected as described above are as follows.

Power is applied from the power supply stage 50 and is applied to the microcontroller 60. In order to drive the magnetron 70 according to the cooking signal selected by the user, the microcontroller 60 outputs an operation signal to the magnetron 70. Accordingly, when the operation signal is transmitted to the magnetron 70 by the on operation of the first power relay 10 and the second power relay 20, the magnetron 70 is driven. When the first power relay 10 and the second power relay 20 are turned off, the magnetron 70 stops.

High-power commercial microwave ovens with outputs above 1800W require two power relays as magnetron control relays. As shown in FIG. 1, when two power relays 10 and 20 are simultaneously turned on, a large inrush current in a circuit is applied. This may result in damage to the circuit due to the inrush current.

Thus, in order to prevent inrush current applied in the circuit, two inrush relays 30 and 40 are required. That is, the first and second inrush relays 30 and 40 are turned on and the inrush current is limited through the first and second current limiting resistors R1 and R2. At the same time, the first and second power relays 10 and 20 are turned on to output an operation signal to the magnetron 70.

As described above, in order to protect the circuit from damage due to the inrush current, the inrush relays 30 and 40 are configured to increase the manufacturing cost of the circuit.

In addition, since the two inrush relays 30 and 40 should be connected to the microcontroller 60, the number of ports configured in the microcontroller 60 increases. When the number of ports of the microcontroller 60 increases, not only the circuit is complicated but also the unit price increases.

It is therefore an object of the present invention to provide a relay control method of a microwave oven that simplifies the control configuration to prevent inrush current when the power is applied.

In accordance with another aspect of the present invention, there is provided a relay control method of a microwave oven including: a magnetron for generating microwaves, a microcontroller for controlling the driving of the magnetron, and a switching operation such that power is input from the power supply terminal to the microcontroller. A control circuit for a microwave oven including first and second relays, comprising: a first relay operation step of turning on a first relay when power is applied; A determination step of determining whether an on operation time of the first relay has elapsed a predetermined time; The determining step includes a second relay operation step in which the second relay is turned on when a predetermined time elapses.

Hereinafter, the relay control method of the microwave oven according to the present invention will be described.

2 is a relay circuit of the microwave oven according to the present invention, and FIG. 3 is an operation control flowchart for driving control of the relay circuit of the microwave oven according to the present invention.

First, referring to the connection relationship of the relay circuit, the power supply terminal 120 is connected to the microcontroller 130. The microcontroller 130 is connected to the first power relay 100 and the second power relay 110. The first and second power relays 100 and 110 are connected to the magnetron 140. Accordingly, when the first and second power relays 100 and 110 are turned on, a driving signal of the microcontroller 130 is transmitted to the magnetron 140 to drive the magnetron 140.

That is, power is applied from the power supply terminal 120 (step 200), and is applied to the microcontroller 130. In order to drive the magnetron 140 according to the cooking signal selected by the user, the microcontroller 130 outputs an operation signal to the magnetron 140.

Accordingly, when the operation signal is transmitted to the first power relay 100 and the second power relay 110 and is on, the operation signal is transmitted to the magnetron 140. When the first power relay 100 and the second power relay 110 are turned off, the magnetron 140 stops driving.

When the output of the microwave oven is 1800W or more, the high power commercial microwave oven requires two magnetron control power relays 100 and 110. By operating the first power relay 100 and the second power relay 110, the output energy of the magnetron 140 is adjusted. As shown in the drawings, the present invention does not constitute a first inrush relay and a second inrush relay for preventing inrush current, unlike the related art.

Therefore, in the present invention, the first power relay 100 and the second power relay 110 for controlling the magnetron, in order to prevent the inrush current applied in the circuit when the initial power is applied after the configuration of the first and second inrush relays are deleted. Do not drive simultaneously.

The present invention drives the first power relay 100 first, and then drives the second power relay 110 when a predetermined time elapses. That is, first, the first power relay 100 is driven (step 210), and then after a predetermined time (about 100 ms as an embodiment of the present invention), the second power relay 110 is driven (step 220). Step 230).

In the case of driving as described above, even if the first and second inrush relays for preventing inrush current, which are conventionally configured in the relay circuit, are deleted, the relay circuit can be safely maintained without departing from the standard value.

As described above, in the present invention, in order to prevent generation of inrush current in a circuit, it is a basic technical idea to sequentially drive a relay at intervals of a predetermined time.

This eliminates the need for a separate control configuration for blocking the inrush current.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

Therefore, due to the relay control method of the microwave oven according to the present invention, the magnetron control relay is sequentially driven in the high-power commercial microwave oven, the inrush current is not generated. Accordingly, while the inrush relay configured in the relay circuit of the conventional microwave oven is not required, the present invention can reduce the manufacturing cost of the relay circuit of the microwave oven.

1 is a relay circuit of a microwave oven according to the prior art.

2 is a relay circuit of a microwave oven according to the present invention.

3 is an operation control flowchart for driving control of a relay circuit of a microwave oven according to the present invention;

           Explanation of symbols on the main parts of the drawings

100, 110: power relay 120: power stage

130: microcontroller 140: magnetron

Claims (1)

In a microwave control circuit comprising a magnetron for generating a microwave, a microcontroller for controlling the driving of the magnetron, and first and second relays for switching power to be input to the microcontroller from a power supply terminal, A first relay operation step of turning on the first relay when power is applied; A determination step of determining whether an on operation time of the first relay has elapsed a predetermined time; And a second relay operation step of turning on the second relay when a predetermined time elapses by the determining step.