KR100198302B1 - Resonance type induction heating cooker - Google Patents

Abstract

The present invention is an electromagnetic induction heating cooker, which is intended to heat a plurality of heating plates using a single inverter, it is also possible to heat each of the plurality of heating plates through time division control to prevent problems caused by interference sound, soft switching The present invention relates to a resonant electromagnetic induction heating cooking device for multi-output control to reduce switching loss using the method.

In case of the conventional frequency control, interference sound is generated between the adjacent wicking coils due to the difference in operating frequency, so that the output power of the working coils cannot be precisely controlled. Since the L and C filters must be configured to smooth and filter the voltages, the entire circuit becomes complicated and there is a problem in that the economics of the device configuration are lacking.

The present invention constitutes one inverter circuit by connecting a plurality of inverter modules in parallel to solve the above problems generated in the electromagnetic induction heating cooking device for multi-output control, DC applied from a common rectifying means By controlling each inverter module through time division control to the power source, multi-output control is achieved, minimizing circuit components, preventing interference noise generated during multi-output control, and switching loss using soft switching method. By minimizing, it is possible to improve the size and economy of the inverter as well as having low noise.

Description

Resonant Electromagnetic Induction Heating Cooker for Multi-Output Control

In the present invention, an electromagnetic induction heating cooker, in which each inverter module is connected in parallel, configures one inverter circuit and heats a plurality of heating plates, respectively, through time division control of each inverter module. The present invention relates to an electromagnetic induction heating cooking apparatus for multi-output control to prevent problems caused by interference noises and to reduce switching losses using a soft switching method.

In the conventional electromagnetic induction heating cooking apparatus for multi-output control, in order to heat a plurality of working coils, a plurality of inverter circuits are configured in parallel with one input power source, and the configuration and operation thereof will be described with reference to FIG. Is as follows.

As shown in FIG. 1, the conventional electromagnetic induction heating cooking unit includes a power supply unit 1 for supplying power to each circuit unit, and includes a rectifying unit rectifying power input through the power supply unit 1. 2), a circuit comprising a choke coil L1 and a capacitor C1 for smoothing the rectified power, and a component of an inverter 3 for heating the heating plate by switching the smoothed power input. Characterized in that a plurality (n) is connected to the supply unit 1, the inverter 3 is a switching element that is switched to receive the switching power supplied from the configured Switched Mode Power Supply (SMPS) unit as a base (Q1, Q2), diodes (D1, D2), resonant capacitor (C2), and the switching element are arranged in reverse parallel to each of the switching elements (Q1, Q2) for protection of the switching elements (Q1, Q2) Receives the power delivered by the switching of (Q1, Q2) It is configured to include the components of the capacitor (C2) and a working coil (Lr1) to the resonant heating the heating plate.

In the electromagnetic induction heating cooking device having such a configuration, a plurality of working coils (Lr1, Lr2, ...) are used to rectify one input power and heat the heating plate through the inverter circuit. In order to heat .., Lrn, the inverters 3, 3-1, 3-2 ...., 3-n are configured in parallel as described above to enable this.

Then, in the conventional electromagnetic induction heating cooking apparatus to heat the plurality of heating plates as described above, looking at the heating operation process of the working coil as follows.

Power supplied from the power supply 1 is rectified to DC power through the rectifier 2, the power rectified in the rectifier 2 is smoothed through the choke coil (L1) and condenser (C1) inverter (3) is applied.

Inverter 3 receives the same power as above to heat the working coil Lr1 by switching the switching elements Q1 and Q2, thereby heating the cooking object of the heating plate, and thus switching elements Q1 and Q2. The switch receives a separate switching voltage from the SMPS unit (not shown in the figure) to perform the switching.

Looking at the heating operation of the working coil (Lr1) by the switching operation of the switching elements (Q1, Q2), the SMPS unit first applies the initial switching voltage to the base of the switching element (Q2).

The switching element Q2 is switched on by a switching voltage applied to the base, and the power applied through the rectifying unit 2 by the switching element Q2 is switched on so that the switching element Q1 is turned off. The loop Loop is formed as the switching element Q2 through the coil Lr1, and the working coil Lr1 resonates by the loop formed as described above.

At this time, when the switching element Q1 is turned on and the switching element Q2 is turned off by applying a switching voltage to the base of the switching element Q1 from the SMPS unit, the switching element Q1 is turned on and switched to the working coil Lr1. The accumulated current forms a loop through the switching element Q1 in the reverse direction, so that current flows through the working coil Lr1.

The switching as described above is repeated to heat the wicking coil Lr1, and the current flowing through the working coil Lr1 is changed according to the on-switching time of the switching elements Q1 and Q2, that is, the duty ratio. Control.

The inverters 3, 3-1, ..., 3-n configured to heat the heating plate by performing the above-described process, and each of the output power control through the frequency control as mentioned above This is achieved by changing the duty ratio.

In this case, interference sound is generated by the difference of operating frequency between adjacent working coils, which prevents accurate output control of the working coils. Since the L and C filters to be smoothed and filtered must be configured, a problem arises in that the entire circuit becomes complicated and the economy in device configuration is lacking.

The present invention proposes a resonance type electromagnetic induction heating cooker in order to solve the above problems generated in the electromagnetic induction heating cooking apparatus for multi-output control, by connecting a plurality of inverter modules in parallel to one inverter circuit And multi-output control by controlling each inverter module through time-division control from a common rectifying means to DC power supply, thereby minimizing circuit components and preventing interference noises generated during multi-output control. It is an object of the present invention to provide an electromagnetic induction heating cooking device capable of controlling the output of the working coil and improving the economic efficiency.

In addition, it is possible to minimize the loss of the switching element by minimizing the switching loss by using a soft switching method.

1 is a circuit diagram showing the configuration of a conventional general electromagnetic induction heating cooking apparatus.

Figure 2 is a circuit diagram showing the configuration of the resonant electromagnetic induction heating cooking apparatus for multi-output control of the present invention.

3 is a resonance electromagnetic induction heating cooking apparatus for multi-output control of the present invention, (a) and (b) is a switching waveform diagram, (c) is a walking waveform by the switching waveform of (a) and (b) (C) is the voltage waveform of the resonant capacitor.

The resonant electromagnetic induction heating cooking device for the multi-output control according to the present invention comprises a power supply means, a rectifying means of the supplied power supply, and a separate switching voltage. A plurality of inverter modules to be heated are made as an inverter circuit connected in parallel, Figure 2 is a view showing a preferred embodiment of the configuration as follows with reference to Figure 2 the configuration of the present invention as follows. .

A rectifier 12 for receiving AC power, which is a commercial power supplied from the power supply 11, and rectifying the pulse current into a pulse; A filter unit including a choke coil L11 and a condenser C11 to filter the power rectified by the rectifying unit 12; Inverter module (13A, 13B) connected in parallel as a component, the inverter unit 13 for receiving the smoothed power input to switch to heat the heating plate; The inverter module 13A includes an auxiliary resonance that resonates with the switching elements Q11 and Q12 having the antiparallel diodes D11 and D12 and the working coil L12 so that the inverter module 13A is switched and controlled by a separate switching power supply. Capacitors C12 and C13, a diode D13 forming a freewheeling path of the resonance current, and the switching plates Q11 and Q12 resonate with the capacitors C12 and C13 in accordance with the switching of the heating plate. It characterized in that it comprises a component of the working coil (L12) for heating.

In this case, when the working coil L12 is operated, the switching element Q12 switches at a predetermined constant iron width, and the switching element Q11 of the switching element Q12 is configured to output a predetermined power to the heating plate. The switching was performed with a variable pulse width having a dead time that does not overlap the pulse width.

The resonance type electromagnetic induction heating cooking device for multi-output control of the present invention having such a configuration adopts one inverter connected in parallel with a plurality of (n) inverter modules to control each of the inverter modules through time division control. The present invention is to enable simultaneous operation or individual operation of the heating plate without the problem of interference sound, for example, to operate only the inverter module (13A), for example, referring to Figure 3 includes the above components characterized in that Referring to the operation of the resonant electromagnetic induction heating cooking device for multi-output control as follows.

In the initial state t0, the switching elements Q11 and Q12 are in an off state, and when a separate switching voltage is applied to the base of the switching element Q11 to turn on the switching element Q11 in the zero voltage and zero current states, The current in the coil L12 is increased linearly as in (c).

After that, when the current of the working coil L12 reaches a predetermined value t1, the switching element Q11 is turned off under the zero voltage condition of the capacitor C13 as in (d).

At this time, the auxiliary resonant capacitor C12 and the working coil L12 resonate for a very short time by the accumulated current of the working coil L12, and the resonance equals the input voltage to the capacitor C12. The voltage of both ends of the working coil L12 drops to zero.

When the charging of the auxiliary resonance capacitor C12 is completed as described above, the working coil L12 resonates with the capacitor C13 through the antiparallel diode D12 connected to the switching element Q12, where t2 When the switching element Q12 is turned on, the current of the working coil L12 continues to resonate with the capacitor C13 in the opposite direction.

By the above operation, the voltage of the capacitor C13 is increased as in (d), and gradually decreases due to the continuous resonance with the working coil L12, and the voltage of the capacitor C13 is zero again. In this case, current flows through the path of the working coil L12-the diode D13-the switching element Q12.

When the current circulates in the above path, there is no change in the current. At this time, when the switching element Q12 is turned off at 5t, the auxiliary resonance capacitor C12 and the working coil L12 are the same as mentioned above. By resonating for a very short time, the voltage of the auxiliary resonant capacitor C12 drops to zero.

When the voltage of the capacitor C12 becomes zero, the remaining current of the working coil L12 flows to the input side through the switching element Q11 antiparallel diode D11, and thus the working coil L12 as in (c). ) Will decrease linearly.

At this time, since the voltage of the switching element Q11 becomes zero again, the switching element Q11 is turned on again in the zero voltage condition at 16.

As described above, when the switching element Q11 is switched on again, as shown in (c), when the current of the working coil L12 drops to zero, one cycle 1T ends.

Here, when the working coil L12 is operated, the switching element Q12 switches at a predetermined constant pulse width, and the switching element Q11 switches the switching element Q12 so that a predetermined power can be output to the heating plate. Switch to a variable pulse width with a dead time that does not overlap with the pulse width of.

If the above operation is repeated, the appropriate power is to be delivered to the working coil (L12).

In the above description, only the operation of only one inverter module 13A is described, and the inverter module 13B also executes the operation by the same operation procedure as described above, so that both the inverter modules 13A and 13B operate. When only two working plates are heated, that is, only one working coil L12 may be heated through time division control, and two working coils L12 and L13 may be simultaneously heated. .

That is, in the above case, in the inverter modules 13A and 13B for heating the heating plate, only one of each of the inverter modules 13A or the inverter module 13B may be operated, and the two inverter modules 13A and 13B may be operated. In order to prevent all interference noises from occurring due to different loads, the time division control between the inverter modules 13A and 13B is enabled.

On the other hand, in the present invention as described above can implement a resonant type electromagnetic induction heating cooking apparatus having four heating plates, as shown in FIG.

This is configured to connect a plurality of (n) inverter modules in parallel to form a single inverter circuit, and to heat the plurality of (n) heating plates using the configured inverter circuit, the same as the above-described operation process It works.

In addition, since the operation of the working coils all use a soft switching method, there is little switching loss.

As described above, the time division control of each of the plurality of inverter modules configured in the inverter circuit prevents the occurrence of interference noise and minimizes the switching loss by using the soft switching method, thereby not only having low noise characteristics but also the size of the inverter. And there is an effect that can improve the problem.

In addition, the heating plate is increasing in the case of the electromagnetic induction cooker commonly used in homes. Application of the present invention, it is possible to design a resonant electromagnetic induction heating cooker having a plurality of heating plates that meet the needs of the user.

Claims (5)

Rectification part 12 for receiving AC, which is a commercial power source, to make a ripple, a filter part for filtering the rectified power consisting of choke coil (L11) and condenser (C11), and switching the switching element by receiving the filtered power. In the induction heating cooker having an inverter unit 13 for heating the heating plate by a plurality of switching elements, a plurality of switching elements (Q11, Q12) having a reverse parallel diode (D11, D12) and the working coil Inverter module 13A composed of L12, a plurality of resonant capacitors C12 and C13, and a diode D13 for forming a current path for resonant current is configured in parallel to the filter unit by the number of heating plates. Resonant electromagnetic induction heating cooking device for multi-output control. The inverter module 13A of claim 1, wherein the inverter module 13A is connected to the switching element Q11 connected in parallel with the resonant capacitor C12 and the anti-parallel diode D11, and the emitter terminal of the switching element Q11 in series. A switching element having an antiparallel diode (D12) connected in parallel with the working coil (L12) connected in parallel with the filter unit and connected in parallel with a diode (D13) forming a reflux path of the resonance current. Resonant type electromagnetic induction heating cooking device for multi-output control, characterized in that (Q12) is configured in parallel to both ends of the working coil (L12). 2. The resonant type electromagnetic induction for multi-output control according to claim 1, wherein the inverter module (13A) has a plurality (n) connected in parallel to heat the plurality (n) of heating plates. Heated cooker. The method of claim 1 or 2, when operating the working coil (L12), the switching element (Q12) is switched to a predetermined constant pulse width, the switching element (Q11) is a predetermined power to be output to the heating plate Resonant electromagnetic induction heating cooking device for multi-output control, characterized in that switching is made to a variable pulse width having a dead time that does not overlap the pulse width of the switching element (Q12). 4. The resonant type electromagnetic induction for multi-output control according to claim 1 or 3, wherein the output control of the inverter unit 13 including the plurality of n inverter modules 13A is performed through time division control. Heated cooker.