KR19980021826A - Half bridge electronic induction heating cooker with multi-load - Google Patents

Abstract

The present invention relates to a half-bridge electromagnetic induction heating cooker having a multi-load, and conventionally controls the output through frequency control. Therefore, if a container of different size is placed on each heating plate, There is a problem in that an interference sound due to a difference in operating frequency is generated and power is supplied to one working coil by an inverter having a separate control circuit, so that the whole system becomes large and the price becomes expensive. Therefore, the present invention drives multiple loads through time sharing with one inverter, so that the overall system configuration is simplified, and a single control circuit can be implemented to reduce the price.

Description

Half bridge electronic induction heating cooker with multi-load

FIG. 1 is a circuit diagram of a conventional multi-output type electromagnetic induction heating cooker. FIG.

FIG. 2 is a circuit diagram of a half-bridge electromagnetic induction heating cooker having a multi-load according to the present invention.

FIG. 3 shows a switching state and a current waveform when each working coil is driven in FIG. 2; FIG.

4 shows another embodiment of a half-bridge electromagnetic induction heating cooker having a multi-load according to the present invention.

FIG. 5 is another embodiment of a half-bridge electromagnetic induction heating cooker having a multi-load according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

20a: first heating section 20b: second heating section

C _f : filter capacitor C _a1 , C _a2 : auxiliary capacitor

C _r1 , C _r2 : resonant capacitor D _a1 , D _a2 : antiparallel diode

L _r1 , L _r2 : Working coil S1, S2:

Ry: Load selection relay

More particularly, the present invention relates to a half-bridge electromagnetic induction heating cooker having a multi-load, and more particularly, it relates to a half-bridge electromagnetic induction heating cooker having a multi-load type in which two or more loads are time- To a multi-load half-bridge electromagnetic induction heating cooker that reduces the cost and size of the entire system.

The circuit configuration of the conventional multi-output type electromagnetic induction heating cooker includes rectifying means for rectifying the input commercial power AC to a pulsating DC voltage and outputting the same, A smoothing means for smoothing the pulsating DC voltage rectified through the rectifying means to convert the pulsating DC voltage into a constant DC voltage; Inverter means comprising two switches having an anti-parallel diode configured in series with a smoothed DC voltage through the smoothing means and switching according to a switching control signal to provide a resonant voltage to the working coil; And a heating coil which induces an eddy current to be heated by an electromagnetic induction effect by a magnetic field generated by a resonance voltage by the inverter means and which is heated.

Hereinafter, a conventional technique configured as described above will be described.

An input commercial power source (AC) and rectified by the bridge diode rectifying (1a) made wherein pulse DC voltage is smoothed by the filter inductor (L _f1) and a capacitor (C _f1) of the smooth portion (2a) constant direct Voltage.

When the switch S2 is first turned on while the DC voltage is supplied to the inverter unit 3a, the input voltage is applied to the resonance tank, the current of the working coil L _r1 is increased by the resonance and the resonance capacitor C _r1 is charged by a resonance current.

When the switch S2 is turned off and the switch S1 is turned on after a short time, the current of the working coil L _r1 flows in the opposite direction due to the discharge of the charging energy of the resonance capacitor C _r1 .

If the above operation is repeated at a high frequency higher than the audible frequency, an appropriate output can be transmitted to the heating plate on the working coil L _r1 .

The switching driving signal for driving the switches S1 and S2 of the inverter unit 3a is transmitted from a microprocessor (not shown).

In the case of driving a plurality of heating plates, a plurality of heating devices 10a shown in FIG. 1 may be connected to a commercial power source AC in parallel.

However, in the conventional technology as described above, since the output is controlled through the general frequency control, if a container of a different size is placed on each heating plate or a different output is outputted, an interference sound And an inverter having a separate control circuit supplies power to one working coil, which increases the overall system and increases the cost.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method and apparatus for driving a plurality of loads using one inverter, And a half-bridge electromagnetic induction heating cooker having a multi-load whose size is reduced.

In order to achieve the above object, a half-bridge electromagnetic induction heating cooker having a multi-load according to the present invention comprises a filter capacitor (C _f ) for improving a power factor of an input voltage as shown in FIG. A first heating unit 20a composed of a working coil L _r1 and a resonance capacitor C _r1 operating with a power source inputted through the filter capacitor C _f to heat the first heating plate; A second heating unit 20b composed of a working coil L _r2 and a resonance capacitor C _r2 operating as a power source inputted through the filter capacitor C _f to heat the second heating plate; Switches S1 and S2 for supplying power to the first and second heating units 20a and 20b so that the first and second heating units 20a and 20b can independently perform the heating operation by performing an on / off switching operation according to a control signal; And a load selection relay Ry capable of selecting either the first heating portion 10a or the second heating portion 20b.

The operation and effect of the present invention will be described in detail as follows.

The portion where the commercial power is rectified and filtered through the filter inductor is omitted and will be discussed from the filter capacitor later.

A case in which the working coil L _r1 operates when supplying a smooth and smooth DC voltage V _d in the filter capacitor C _{f in} order to improve the power factor of the input voltage is as follows.

First, the load selection relay Ry is connected to the first terminal, and the switch S1 is turned off and the switch S2 is turned on as shown in (a) of FIG. 3, so that the resonance tanks L _r1 and C _{r1 are} connected to the filter capacitors Since the smoothed direct current voltage V _d is applied by C _f , the resonance starts and the current rises in the working coil L _{r1 as} shown in (c) of FIG.

When the switch S2 is turned off before the resonance half period passes, the auxiliary capacitors C _a1 and C _a2 and the resonance tanks L _r1 and C _r1 perform the auxiliary resonance so that the voltage of the auxiliary capacitor C _a1 becomes the filter capacitor C _f ) falling from the DC voltage (V _d) to the zero voltage of that between the auxiliary capacitor (C ₂₎ due to rises from zero to the voltage V _d.

Since the parallel translation of the switch (S1) the diode (D _a1) conducts the resonant tank (L _{r1 r1} and C), the applied voltage is zero.

Then, resonance occurs continuously by the voltage charged in the resonance capacitor C _r1 , and at this time, the switch S 1 is turned on under the condition of zero voltage.

The resonance current drops to the resonance current by the subsequent resonance, and this time, by the resonance in the opposite direction, the resonance current increases as shown in (c) of FIG.

When the switch S1 is turned off before the resonance half period passes, the auxiliary capacitors C _a1 and C _a2 and the resonance tanks L _r1 and C _r1 perform the auxiliary resonance so that the voltage of the auxiliary capacitor C _{a2 changes} from V _d to zero While the voltage of the auxiliary capacitor C _a1 rises from zero to V _d .

Thereafter, the antiparallel diode _Da2 is conducted, and the voltage _Vd is applied to the resonance tanks _Lr1 and _Cr1 .

Then, resonance occurs continuously, and at this time, switch S2 is turned on under the condition of zero voltage. When the resonance current drops to zero due to the continued resonance, the operation of one cycle is ended and the same operation is repeated.

The load is heated by the eddy current issued to the load by the induced current.

To operate the working coil L _r2 , the load selection relay Ry is connected to the second terminal, and the switch S 1 is turned off and the switch S 2 is turned on as shown in FIG. 3 (b) L _r1 and C _r1 are resonated as the smoothed DC voltage V _d is applied through the filter capacitor C _f through the auxiliary capacitor C _a1 and the load selection relay Ry to generate resonance with the wicking coil L _r2 ), the current begins to rise.

The subsequent operation supplies the desired output to the load by the same operation as the operation already mentioned above.

The first and second heating units 20a and 20b are alternately turned on and off by time division to heat the two burners at the same time.

In another embodiment of the present invention, when the position of the resonance tank is connected in parallel to the switch S1 or in parallel to the switch S2 as in the fourth and fifth drawings, .

If the number of loads is more than three, configure the resonant tank in parallel, and if the load selection relay is configured as a multi-terminal relay or a two-terminal relay in parallel instead of the three-terminal relay, .

As described above in detail, since the present invention drives several loads with one inverter, the entire system can be simplified, and a single control circuit can be implemented.

Claims (3)

A filter capacitor for improving a power factor of an input voltage; Heating means for selectively heating one or more heating plates according to an input power source; Switching means for performing switching operation by a control signal so that the heating means is selectively heated; And a load selection relay configured to select the heating means and the switching means so as to heat at least one heating plate. The plasma display apparatus according to claim 1, wherein the heating means comprises: a first heating unit configured by a working coil (L _r1 ) and a resonance capacitor (C _r1 ) operating as a power source according to a switching operation of the switching means to heat the first heating plate; And a first heating unit composed of a working coil (L _r2 ) and a resonance capacitor (C _r2 ) operating as a power source inputted in accordance with a switching operation of the switching unit to heat the second heating plate Bridge induction heating cooker. 3. The half-bridge electromagnetic induction heating cooker according to claim 2, wherein the heating section composed of the working coil and the resonance capacitor is expandable to two or more and has a load selection relay matching the number of the heating sections.