JPH01298672A - induction heating cooker - Google Patents

Abstract

PURPOSE:To use one cooling fans and one power transformers for a plurality of invertor circuits and reduce the cost, size and weight by providing two switching relays. CONSTITUTION:When a second switch 8 is turned on, for example, one of a cooling fan 13 and a power source transformer 14 is connected to a power source line 6 through a common contact 10c and a normally closed contact 10d of a second relay 10, and thus these are operated. A power source is supplied also to the contact driving coil 9a of a first relay 9 to switch the contact of the relay 9 from 9d to 9b, and 9d is opened. The fan 13 and the transformer 14 continue to operate regardless of the on/off of a first switch 7. Similarly, when the switch 7 is turned on, the fan 13 and the transformer operate regardless of the switch 8. Hence, by providing switching relays in this way, a plurality of invertor circuits can be operated by one power source transformer and cooled by one cooling fan.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is directed to 3? The present invention relates to an induction heating cooker that uses a fs AC power source and has a plurality of heating parts.

Conventional technology The general configuration of an induction heating cooker is to use commercial alternating current as a power source, rectify it, apply it to a high frequency inverter, generate a high frequency current of about 20 to 30 KHz and apply it to the induction heating coil, and generate a high frequency alternating magnetic field. This heats the pot by induction. In this type of cooking appliance, a large current flows through the electrical components that make up the inverter circuit and generates heat, so it is widely adopted that a cooling fan is provided inside the cooking appliance.

On the other hand, in a conventional cooker of this kind that has a plurality of heating parts and uses a three-wire AC power supply, as shown in FIG. 5, an inverter circuit 11.1 having a cooling fan 13 and a heating part
2 were respectively provided between the two-wire AC power sources 1, and inverter circuits 11 and 12 having a cooling fan 13 and a heating section were operated independently between the two-wire AC power sources.

Note that 7 is a power switch for the inverter circuit 11, and 8 is a power switch for the inverter circuit 12.

14 is a power transformer which is a power supply section of the inverter circuits 11 and 12.

Problems to be Solved by the Invention In such a conventional configuration, a cooling fan 13 and a power transformer 14 are required between each two-wire AC power supply 1, which increases the cost and also increases the cost of the cooling fan 1.
The problem was that it required space to place 3, making it impossible to make it smaller and lighter.

The present invention solves this problem by providing one cooling fan and one power transformer, and when any heating section or inverter circuit is being driven, the cooling fan and power transformer are always connected. It is designed to operate when power is supplied.

Means for Solving the Problems In order to achieve the above object, the first means of the present invention is as follows:
at least two or more inverter circuits each connected between a first power line of a line AC power source in common and other second and third power lines; a first switch function means each having a switch function arranged between the third power supply line and the inverter circuit;
A switch function means, a cooling fan that cools each of the inverter circuits, and a power transformer that supplies power to each of the inverter circuits, the first power supply line being connected between the first power supply line, the second switch function means, and the inverter circuit. 5th with
a first having a drive coil connected between it and the power supply line;
a second relay having a drive coil connected between a common contact of the first relay and a first power supply line; Connect the normally closed contact of 1 relay,
The common contact of the first relay and the normally open contact of the second relay are connected, the fifth power line and the normally open contact of the second relay are connected, and the cooling fan and the power transformer are connected in parallel. The cooling fan is configured to be connected between the first power supply line and the common contact of the second relay, and when at least one of the means having each of the switch functions is closed, the cooling fan is driven; Power is supplied to the power transformer. Further, in the second means, an inverter circuit having a higher output is connected between the power supply line and the fifth power supply line. Furthermore, the third means is such that the operating time of the second relay is slower than the operating time of the first relay.

Effect The effect of the above first means is as follows. First, the case where the second switch function means is ONI will be explained. Second
When the switch function means is turned on, one of the cooling fan and the power transformer is connected to the fifth power line and the third power line via the common contact and the normally closed contact of the second relay, and the operation starts.

At this time, the same power is supplied to the drive coil of the first relay, so the contacts of the first relay are switched and the contacts are opened. Therefore, the cooling fan and the power transformer continue to operate regardless of the 0N10FF state of the first switch function means.

That is, if the second switch function means is in the ON state, the cooling fan and the power transformer are always connected to the first power supply line and the third power supply line, regardless of the 0N10FF state of the first switch function means.
It is connected to the power supply line and the fifth power supply line and continues to operate.

Next, a case where the first switch function means is turned ON or OFF while the second switch function means is OFF will be described.

When the first switch function means is turned on, the drive coil of the second relay is connected between the fourth power line and the first power line via the normally closed contact and the common contact of the first relay. The contacts of the cooling fan and power transformer are connected to the first power line, the second relay and the second relay.
It is connected to the fourth power supply line through the contact with the relay and starts operating. Furthermore, when the second switch function means is turned on next time in this state, power is supplied to the drive coil of the first relay, so the contacts of the first relay are switched to the open state, and the power is supplied to the drive coil of the second relay. is canted, and at the same time, the contacts of the second relay are also switched. Therefore, the cooling fan and the power transformer operate while being connected between the fifth power line and the first power line via the contacts of the second relay. Then, when the second switch function means is turned OFF again, the power to the drive coil of the first relay is cut off, the contacts of the first relay are switched υ, and power is supplied to the drive coil of the second relay, so that The contacts of the two relays are also switched at the same time, and the cooling fan and power transformer are connected and operated between the fourth power line and the first power line through the contacts of the first and second relays. That is, if the second switch function means is turned ON while the first switch function means is ON, the contacts of the first and second relays are both switched.The power supply for the anti-cooling fan and power transformer is connected to the first power line and The contacts of the first and second relays are switched to connect the fourth power line to the first power line and the fifth power line, and in the opposite direction when turned off.

At this time, when the second switch function means is turned ON while the first switch function means is ON, the second relay is switched if the contact switching of the first relay is slow or the contact chattering. To improve the problem of high voltage being applied between relay contacts, causing shear arcs to fly and the contacts to weld.

As in the third means, the operating time of the second relay is made slower than the operating time of the first relay.

In addition, while the first switch function means is ON, the second switch function means is turned on.
When the switch function means is turned ON or OFF, the first
After the contacts of the relay switch, the contacts of the second relay switch, so the power on the primary side of the power transformer is cut off for a moment between the contacts of the first relay switching and the second relay starting to operate. The power supply to the inverter circuit connected to the first switch function means is momentarily cut off, and the normally operating inverter circuit becomes momentarily unstable. Therefore, in order to reduce the operation of the inverter circuit in an unstable state, as in the second method, the inverter circuit in which the supply from the power transformer is momentarily cut off is connected to the one with the lower output. .

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

In Figure 1, 1 is a single-phase three-wire AC power supply (100/20
0V), the first power supply line 2 which is the ground is common, and the second power supply line 3 and the third power supply line which are hot lines are
The power line 4 is connected to a fourth power line 5 and a fifth power line 6 via a first switch function means (switch 1) 7 and a second switch function means (switch 2) 8, each having a switch function. . The first common
Inverter circuits 11 and 12 are provided between the power supply line 2 and the fourth power supply line 6, and between the fifth power supply line 6 and the fifth power supply line 6, respectively.
is connected.

13 is a cooling fan that cools each inverter circuit 11 and inverter circuit 12; 14 is a power transformer that cools each inverter circuit 11 and inverter circuit 1;
2, cooling fan 13 and power transformer 1
4 is connected in parallel.

9 is a first relay, and a drive coil 9a that drives its contacts.
is connected between the first power line 2 and the fifth power line e, and its normally closed contact 9d is connected to the fourth power line 6,
The normally open contact 9b is open.

1o is the second relay, and the drive coil 1 that drives its contacts
0a is the normally open contact 1 between the first power line 2 and the second relay 1°
0b, and the normally closed contact 10d is connected to the fifth power supply line e. Further, the common contact 9c of the first relay 9 and the normally open contact 10b of the second relay 1° are connected. One of the cooling 71-line 13 and the power transformer 14 connected in parallel is connected to the first power line 2, and the other is connected to the common contact 10c of the second relay 1o.

In the above configuration, the case when the switch 2 (8) is turned on will be explained first. When the switch 2 (8) is turned on, one of the cooling fan 13 and the power transformer 14 is connected to the fifth power line 6 via the common contact 10c and the normally closed contact 10d of the second relay 1o, so that the operation starts. .

On the other hand, since power is also supplied to the contact drive coil 9a of the first relay 9, the contacts of the first relay 9 change from contact 9d to contact 9b.
Then, the contact 9c and the contact 9d are opened. Therefore, the cooling fan 13 and the power transformer 14 continue to operate regardless of whether the switch 17 is 0N10FF. In other words, if switch 2 (8) is always ON, switch 1
Regardless of (7), the cooling fan 13 and the power transformer 1
4 continues to operate because it is always connected to the first power line 2 and the fifth power line 6 with priority.

Next, with switch 2 (8) turned off, switch 1
c7) is turned ON or OFF.

First, when the switch 1 (7) is turned on, the contact drive coil 10a of the second relay 10 connects the normally closed contact 9d of the first relay 9.
Since the second relay 10 is connected to the fourth power line 6 and the first power line 2 through the common contact 9C, the contact of the second relay 10 is switched from the contact 10d to the contact 10b, and the cooling fan 13 and the power transformer are connected to each other. 14 starts operating because it is connected to the first power line 2 and the fourth power line 6 via the contacts 10c and 10b of the second relay 10 and the contacts 9C1 and 9d of the first relay 9. By the way, if switch 2 (8) is also turned on in this state, the first relay 9
Since the contact drive coil 9a is connected to the first power line 2 and the fifth power line 6, the contact of the first relay 9 is switched from the contact 9d to the contact 9b, and the power supply of the contact drive coil 10a of the second relay 10 is switched from the contact 9d to the contact 9b. is cut and the second relay 10
At the same time, the contact point υ is switched from the contact point 10b to the contact point 10d.

Therefore, one of the cooling fan 13 and the power transformer 14 is connected to the contact 10d of the second relay 1° from the fourth power line 5.
10C to the fifth power supply line 6, and the other is connected to the first power supply line 2 for operation. Then, when the switch 2 (8) is turned off, the power to the contact drive coil 9a of the first relay 9 is cut off, and the contact of the first relay 9 is switched from the contact 9b to the contact 9d again, and the second relay 1
o contact drive coil 10a is again connected to the first power supply line 2.

Contact 10b of second relay 10, contact 9C of first relay 9
The contacts of the second relay 10 are also simultaneously switched from the contacts 10d to the contacts 10b, and finally the cooling fan 13 and the power transformer 14 are in their initial state. Contacts 9d and 9C1 of the first relay 9 and contacts 1ob and 1 of the second relay 10
It operates by being connected to the fourth power line 6 and the first power line 2 via 0c. That is, switch 1 (7) is O.
If the switch 2 (8) is further turned ON in the N state, the contacts of the first relay 9 and the second relay 1o are switched, and the power supply of the cooling fan 13 and the power transformer 14 is connected to the first power line 2 and the fourth power line. The connection from the power line 5 to the first power line 2 and the fifth power line 6 can be switched to the opposite direction when the switch 2 (8) is then turned off.

Next, switch 2 (8) is OFF and switch 1) is OFF.
Even when it goes from N to OFF, the contact point of the second relay is 10.
b switches to 1od, and the operation of the inverter circuit stops.

As described above, two relays are provided, and the first relay 9 and the drive coil 9a that drive the contacts thereof are connected between the first power line 2 and the fifth power line 6, and the normally closed contact 9d is connected to the first relay 9a. 4 connected to the power supply line 6, the normally open contact 9b is open, and the second relay 10 is connected to the drive coil 1 that drives the contact.
0a is the normally open contact 1 of the first power line 2 and the second relay 10
0b, its normally closed contact 1od is connected to the fifth power supply line 6, and the common contact 90 of the first relay 9 and the normally open contact 1ob of the second relay 1o are connected, and further connected in parallel. One of the cooling fan 13 and the power transformer 14 is connected to the first power line 2, and the other is connected to the common contact 10c of the second relay 1o.
Or, if at least one of them is turned on, either one of the power supplies is always supplied to the cooling fan 13 and the power transformer 14 by a switching circuit composed of two relays, and the cooling fan 13 and the power transformer 14 are operated.

As explained above, the rust induction heating cooker of the present invention is equipped with a plurality of heating parts using a switching circuit composed of two relays, and each of the inverter circuits constituting these parts is connected to one inverter circuit. A single power transformer can supply power to each inverter circuit, simplifying the circuit configuration, reducing the number of parts, lowering the price, reducing weight, and making the inverter more compact. be able to.

Next, in FIG. 2, an inverter circuit 12 having a heating section with a large output is connected between the first power line 2 and the fifth power line 6. In FIG.

In the above configuration, when switch 2 (8) is turned on or off while switch 1 (force is on), its contacts are sequentially switched first to first relay 9 and then to second relay 10. Between the time when the contact of the first relay 9 is activated and the time when the contact of the second relay 1o is completely switched, the power on the primary side of the power transformer 14 is in an open state and is momentarily cut off, so that the normally operating inverter is circuit 1
1 becomes an instantaneous unstable operating state.

Therefore, in order to reduce the operation of the inverter circuit 11 in an unstable state, and to reduce the power loss when the power supply of the power transformer 14 is switched and to perform stable operation, the power supply from the power transformer 14 is instantaneous. The inverter circuit 11 to be cut is connected to the one with the smaller output.

Next, in FIGS. 3 and 4, the operating time of the second relay 10 is delayed from the operating time of the first relay 9.

While switch 1 (7) is ON, switch 2 (
8) is turned on, if the switching of the contacts of the first relay 9 is slow or the contacts chattering, high voltage 2o○■ is applied between the contacts of 1ob and 10d when the second relay 10 is switched. There is a problem with the arc jumping and the contacts welding.

In order to improve this, the operating time of the second relay 10 is set to be appropriately slower than the operating time of the first relay 9, and as shown in FIG.
The contact drive coil 10a of the second relay 1o may be connected in parallel with the contact drive coil 10a of the second relay 10, or the second relay 10 may be a DC relay as shown in FIG. It is provided at the output terminal of the rectifier 16 connected to the normally open contact 10b of the relay 1o, and after the contact of the first relay 9 is completely switched, the second relay 10 is connected to the normally open contact 10b of the relay 1o.
A time difference is provided so that the contacts switch between the two.

In the above configuration, by appropriately delaying the operation time of the second relay 1Q than the operation time of the first relay 9, the first
Even if the contacts of the relay 9 chatter, there is a time difference between the operation completion time of the first relay 9 and the operation start time of the second relay 1°. This prevents the contacts from welding due to the application of high voltage and arcing.

In FIG. 3, the contact drive coil 1 of the second relay 10 is
A CR circuit 16 consisting of a resistor and a capacitor is connected in parallel with 0a, and when power is applied to the contact drive coil 10a, a time constant is provided by the CR to intentionally delay the start time of the second relay 1o. This prevents a high voltage from being applied between the contacts 10b and 1od of the second relay 1o and causing the contacts to weld due to arcing.

In FIG. 4, the second relay 1o is a DC relay, and the contact drive coil 10a of the second relay 1o is provided at the output terminal of a rectifier 16 connected to the first power supply line 2 and the normally open contact 10b of the second relay 1o. By utilizing the charging time of the smoothing capacitor provided at the output terminal of the rectifier 1e and intentionally delaying the operation time of the second relay 1o in the same manner as described above, the contacts of the second relay 10 are welded by arc. This is to prevent

Here, although not shown, the contact 10b of the second relay 1o
If a surge absorber, such as a ZNR or CR circuit, is provided between the contact point 10d and the contact point 10d, the second
This makes it possible to more effectively prevent the contacts of the relay 10 from being welded by arc.

In addition, in the above embodiment, the switch function means is a switch, but it is not limited to this, and a semiconductor switching element such as a tora-yu book may be used, and the above-mentioned semiconductor switching element may also be used in a relay. Even if the invention is opened, the effects of the present invention can be achieved.

In addition, the 3-wire AC power supply can be replaced with a single-phase 3-wire AC power supply (100/20
However, the effects of the present invention can be achieved even if two three-phase three-wire AC power supplies or two two-wire commercial power supplies are used.

Effects of the Invention As is clear from the description of the embodiments, the present description provides the following effects.

(1) Since a switching relay is provided, each inverter circuit can use only one power transformer.

(2) Since a switching relay is provided, each inverter circuit can be cooled with one cooling fan.

(3) Since a switching relay is provided, multiple inverter circuits can be cooled with one cooling fan, and one power transformer can supply power to multiple inverter circuits, reducing the number of parts.

It can be made more compact, lighter, and cheaper.

(4) The output of the power transformer decreases when the relay is switched.Since the inverter circuit with the smaller output is connected to the power supply side, the inverter circuit operates stably when the relay is switched.

(6) Since the operating time of the second relay is set to be appropriately slower than the operating time of the first relay, welding of the contacts of the second relay can be prevented.

[Brief explanation of the drawing]

1, 2, 3, and 4 are circuit diagrams of an induction heating cooker showing an embodiment of the present invention, and FIG. 5 is a circuit diagram of an induction heating cooker showing a conventional example. 1... 3-wire AC power supply, 7... First switch function means, 8... Second switch function means,
9...First relay, 1o...Second relay, 11. 12...Inverter circuit, 13.
... Cooling fan, 14 ... Power transformer, 16 ... CR circuit, 16 ... Rectifier. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
Section 3 AC source γ - 1st switch switch 8 - 2nd switch function 9 - 1st relay 10 --- ＼＼Ware 14 - Power source transformer 2nd figure 8 /Z 3rd figure 75 ~ CF circuit l Otsu 16 ---Kanaku 5 Figure 4 Figure 5

Claims (3)

[Claims] (1) At least two or more inverter circuits each connected between a first power line of a three-wire AC power supply in common and other second and third power lines, and a second inverter circuit other than the first power line; A first switch function means and a second switch function means each having a switch function are arranged between the third power supply line and the inverter circuit, a cooling fan for cooling each of the inverter circuits, and a cooling fan for cooling each of the inverter circuits. a power transformer for supplying power;
a first relay having a drive coil connected between a power supply line and a fifth power supply line between the second switch function means and the inverter circuit; a common contact of the first relay and a first relay;
a second drive coil connected between the power supply line and the drive coil;
a relay, connecting a fourth power line between the first switch function means and the inverter circuit and a normally closed contact of the first relay, and a common contact of the first relay and a normally open contact of the second relay; , connect the fifth power line and the normally open contact of the second relay, connect the cooling fan and the power transformer in parallel, and connect the first power line and the second relay common contact. The induction heating cooker is configured such that the cooling fan is driven and power is supplied to the power transformer when at least one of the means having the switch function is closed. (2) The induction heating cooker according to claim 1, wherein an inverter circuit with a higher output is connected between the first power line and the fifth power line. (3) The induction heating cooker according to claim 1 or 2, wherein the operating time of the second relay is appropriately slower than the operating time of the first relay.