KR101757976B1 - Induction heat cooking apparatus and method for driving the same - Google Patents

Abstract

An electromagnetic induction heating cooker according to the present invention includes: a rectifier for rectifying an input voltage and outputting a DC voltage; A DC capacitor connected to both ends of the rectifying unit; A plurality of switching elements for switching a DC voltage output through the rectifying part; A plurality of heating coils heating the cooking vessel according to the control of the plurality of switching elements; And a control unit for controlling the plurality of switching elements, wherein the plurality of heating coils includes a first heating coil, a second heating coil, and a third heating coil, and a resonance capacitor connected at one end to the second heating coil And the other end of the resonance capacitor is connected to one of the positive power terminal and the negative power terminal of the rectifying unit and the other end of the resonance capacitor is connected to the other of the positive power terminal and the negative power terminal of the rectifying unit, The control unit controls the plurality of switching elements so that the second heating coil and the third heating coil are connected in parallel and simultaneously driven.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction heating cooker, and more particularly, to an electromagnetic induction heating cooker including a plurality of switching elements and a plurality of resonance circuits and a driving method thereof.

Generally, an induction heating cooker causes a high frequency current to flow through a working coil or a heating coil, and when a strong magnetic force line generated by the induction heating cooker passes through a cooking vessel, eddy current flows and the container itself is heated And performs the cooking function by the method described above.

The basic heating principle of the induction heating cooker is as follows. When a current is applied to the heating coil, the cooking vessel, which is a magnetic body, generates heat by induction heating, and the cooking vessel itself is heated by the generated heat, .

The inverter used in the induction heating cooker serves to switch the voltage applied to the heating coil so that a high-frequency current flows through the heating coil. The inverter drives a switching element, typically an IGBT (Insulated Gate Bipolar Transistor), so that a high frequency current flows through the heating coil to form a high frequency magnetic field in the heating coil.

When two heating coils are provided in the induction heating cooker, two inverters formed of four switching elements are required to operate the two heating coils.

1 is a view for explaining an induction heating cooker according to the prior art.

1 shows an induction heating cooker including two inverters and two heating coils.

1, the induction heating cooker includes a rectifying section 10, a first inverter 20, a second inverter 30, a first heating coil 40, a second heating coil 50, a first resonance capacitor (60) and a second resonant capacitor (70).

The first and second inverters 20 and 30 have first and second heating coils 40 and 50 driven by the output voltage of the switching device, Connected to the connection point of the serially connected switching elements. The other side of the first and second heating coils 40 and 50 is connected to the resonant capacitors 60 and 70.

The driving of the switching element is performed by a driving part, and the switching elements are alternately operated by the switching time outputted from the driving part to apply a high frequency voltage to the heating coil. Since the on / off time of the switching element to be applied to the driving unit rotor is controlled to be gradually compensated, the voltage supplied to the heating coil changes from a low voltage to a high voltage.

However, in such an induction heating cooker, two inverter circuits including four switching elements must be included in order to operate two heating coils, thereby increasing the product volume and raising the product price .

In addition, when the number of heating coils increases to three or more, there is a problem that a large number of switching elements are required depending on the number of heating coils.

An embodiment of the present invention is to provide an electromagnetic induction heating cooker capable of controlling an electromagnetic induction heating cooker equipped with a plurality of heating coils with a minimum number of switching elements and a control method thereof.

It is another object of the present invention to provide an electromagnetic induction heating cooker capable of driving a plurality of heating coils together with a minimum number of switching elements in an electromagnetic induction heating cooker provided with a plurality of heating coils and a control method thereof .

The embodiments of the present invention also provide an electromagnetic induction heating cooker capable of reducing instantaneous overcurrent generated in a process of turning on or off a switching device to reduce current ripples in a rectifying circuit and reduce heat generation, and a control method thereof .

The other end of the resonant capacitor connected to the second heating coil is connected to one of the positive power terminal and the negative power terminal of the rectifying unit and the other end of the resonant capacitor connected to the third heating coil, And the control unit controls the plurality of switching elements so that the second heating coil and the third heating coil are connected in parallel to be simultaneously driven.

At this time, the first heating coil may have a larger capacity than the second heating coil or the third heating coil, and the second heating coil and the third heating coil may have the same capacity.

The embodiments of the present invention can provide an electromagnetic induction heating cooker and a control method thereof that can control an electromagnetic induction heating cooker provided with a plurality of heating coils with a minimum number of switching elements.

In addition, embodiments of the present invention can provide an electromagnetic induction heating cooker capable of driving a plurality of heating coils together with a minimum number of switching elements in an electromagnetic induction heating cooker provided with a plurality of heating coils, and a control method thereof.

Also, an embodiment of the present invention provides an electromagnetic induction heating cooker capable of reducing an instantaneous overcurrent generated in a process of turning on or off a switching device, thereby reducing current ripples in a rectifying circuit and reducing heat generation, and a control method thereof .

1 is a view for explaining an induction heating cooker according to the prior art.
2 is a view for explaining a structure of an electromagnetic induction heating cooker according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a control unit for controlling a switching device in an embodiment of the present invention. FIG. 4 is a diagram illustrating a gate driver for operating a switching device in an embodiment of the present invention. Figure 2 illustrates a switching mode power supply in an example.
Figs. 6 and 7 are views showing signals for driving respective heating coils in the embodiment of the present invention. Fig.
8 is a diagram showing signals for driving a plurality of heating coils in a time division manner in the embodiment of the present invention.
9 is a diagram showing signals for driving a plurality of heating coils in a duty control manner in the embodiment of the present invention.
10 is a diagram showing signals for driving two heating coils in a parallel driving manner in the embodiment of the present invention.
11 and 12 are views for explaining the change of the current flowing through the heating coil and the voltage across the DC capacitor according to the connection direction of the resonant capacitor in the embodiment of the present invention.
FIG. 13 is a view for explaining the temperature change of the heat generated in the bridge diode of the rectifying part according to the connection direction of the resonant capacitor in the embodiment of the present invention. FIG.
14 is a view for explaining a structure of an electromagnetic induction heating cooker according to another embodiment of the present invention.
FIG. 15 is a view showing a control unit for controlling a switching device in another embodiment of the present invention, FIG. 16 is a view showing a gate driver for operating a switching device in another embodiment of the present invention, and FIG. Lt; RTI ID = 0.0 > a < / RTI > switched mode power supply.
18 and 19 are diagrams showing signals for driving respective heating coils in another embodiment of the present invention.
20 is a diagram showing signals for driving a plurality of heating coils in a time division manner in another embodiment of the present invention.
21 is a diagram showing signals for driving a plurality of heating coils in a duty control manner in another embodiment of the present invention.
22 is a diagram showing signals for driving two heating coils in a parallel driving manner in another embodiment of the present invention.

Hereinafter, an electromagnetic induction heating cooker and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 to 13 are views for explaining an electromagnetic induction heating cooker and a control method thereof according to an embodiment of the present invention.

2 is a view for explaining a structure of an electromagnetic induction heating cooker according to an embodiment of the present invention.

Referring to FIG. 2, the electromagnetic induction heating cooker includes a rectifier 210 for receiving commercial AC power from the outside and for rectifying the AC power to a DC power source, and a rectifier 210 for rectifying both ends of the rectifier 210, A second switching element 222, a third switching element 223 and a fourth switching element 224 which are connected in series to each other and are switched in accordance with a control signal, The other end is connected between the first resonance capacitor 261 and the second resonance capacitor 262, one end of which is connected to the contact point between the first switching device 221 and the second switching device 222 and is connected to one end and the other end of the rectifying part 210, A third resonant capacitor 263 having one end connected to a contact point between the second switching device 222 and the third switching device 223 and connected to the other end of the rectifying part 210, A second heating coil 242 connected to the other end of the third switching device 223, And a third heating coil 243 having one end connected to a contact between the switching elements 224 and the other end connected to a fourth resonant capacitor 264 connected to the other end of the rectifying part 210.

Further, although not shown, a control unit for controlling the switching operation of the switching elements 221, 222, 223, and 224 is further included. In the embodiment, three heating coils are provided.

In the embodiment, when the number of the heating coils is N, N + 1 switching elements may be provided, and it is possible to drive the heating coils while minimizing the number of switching elements.

The first switching device 221 has one end connected to the positive power supply terminal and the other end connected to the second switching device 222. The second switching device 222 has one end connected to the first switching device 221 and the other end connected to the third switching device 223. The third switching device 223 has one end connected to the second switching device 222 and the other end connected to the fourth switching device 224. The fourth switching device 224 has one end connected to the third switching device 223 and the other end connected to a negative power terminal.

The DC capacitor 290 may further include a DC capacitor 290 connected to both ends of the rectifying part 210. The DC capacitor 290 may reduce the ripple of the DC voltage output from the rectifying part 210. [

The first heating coil 241 is connected between the first resonant capacitor 261 and the second resonant capacitor 262. However, the first resonant capacitor 261 or the second resonant capacitor 262 may be connected to the first resonant capacitor 261, The capacitor 262 may not be provided.

Meanwhile, in the embodiment, the second heating coil 242 is connected to the third resonant capacitor 263 connected to the positive power terminal, and the third heating coil 243 is connected to the negative power terminal The fourth heating coil 242 is connected to the fourth resonant capacitor 264 connected to the negative power terminal and the third heating coil 243 is connected to the fourth resonant capacitor 264, And may be connected to the third resonant capacitor 263 connected to the positive power terminal.

The second heating coil 242 and the third heating coil 243 may have the same capacity and the second heating coil 242 and the third heating coil 243 may be simultaneously driven in parallel .

When the second heating coil 242 and the third heating coil 243 are simultaneously driven in parallel, the switching elements 221, 222, 223, and 224 operate as described below with reference to FIG. 10, Since the overcurrent generated in the section where the switches 221, 222, 223 and 224 are closed (turned on) and the section that is opened (turned off) is branched to the positive power terminal and the negative power terminal, the instantaneous overcurrent section can be reduced.

If the third resonant capacitor 263 connected to the second heating coil 242 and the fourth resonant capacitor 264 connected to the third heating coil 243 are both the positive power terminal or the negative power terminal An overcurrent flows to the positive power terminal or the negative power terminal. As a result, when the second heating coil 242 and the third heating coil 243 are driven at the same time in parallel, the current ripple is large and the rectifying part 210 generates heat.

Therefore, in the present invention, the third resonant capacitor 263 and the fourth resonant capacitor 264 are connected to the positive power terminal and the negative power terminal, respectively, thereby reducing the current ripple and reducing the heat generation.

An anti-parallel diode may be connected to the switching elements 221, 222, 223, and 224, and an auxiliary resonance capacitor connected in parallel to the anti-parallel diode may be connected to minimize the switching loss of the switching elements.

FIG. 3 is a view illustrating a control unit for controlling a switching device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a gate driver for operating a switching device according to an embodiment of the present invention. Mode power supply according to an embodiment of the present invention.

3 to 5, the controller 280 is connected to the inputs G1, G2, G3 and G4 of the first, second, third and fourth gate drivers 291, 292, 293 and 294 for driving the switching elements 221, 222, And the outputs GD1, GD2, GD3 and GD4 of the gate drivers 291, 292, 293 and 294 are connected to the gate terminals of the switching elements 221, 222, 223 and 224. As shown in FIG. 5, the power source supplied to the gate drivers 291, 292, 293, and 294 is an independent power source of the multiple output SMPS.

Therefore, a signal from the controller 280 is applied to the gate drivers 291, 292, 293, and 294 to drive the semiconductor switches to control the respective switching elements 221, 222, 223, and 224.

A current transformer 270 may be provided between the ground of the switching elements 221, 222, 223 and 224 connected in series and the first, second and third heating coils 241, 242 and 243, The currents flowing through the heating coils 241, 242 and 243 are measured and input to the controller 280 through the analog-to-digital converter (ADC) provided in the controller 280. The control unit 280 controls the switching devices 221, 222, 223, and 224 based on the current value.

Figs. 6 and 7 are views showing signals for driving respective heating coils in the embodiment of the present invention. Fig.

6 and 7, the controller 280 controls the currents flowing through the first, second, and third heating coils 241, 242, and 243 by controlling the switching elements 221, 222, 223, and 224.

When the control unit 280 intends to drive the first heating coil 241, the first switching device 221 is closed for half a period of resonance, and the second, third, and fourth switching devices 222, 223, and 224 are controlled to be in an open state. Then, the first switching device 221 is brought into the open state and the second, third, and fourth switching devices 222, 223, and 224 are controlled to be in the closed state during the half period of the remaining resonance.

During the half period of the resonance through the above operation, an input voltage is applied to the first heating coil 241 and the first and second resonance capacitors 261 and 262, thereby starting resonance, The current rises. The input voltage is applied to the first heating coil 241 and the first and second resonant capacitors 261 and 262 in a half period of the other resonance, and resonance starts to be applied to the first heating coil 241 and the first heating coil 241 Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the first heating coil 241, so that the electromagnetic induction heating cooker operates.

7, when the control unit 280 intends to drive the second heating coil 242, the first switching device 221 and the second switching device 222 are closed for half a period of the resonance, State, and controls the third and fourth switching devices 223 and 224 to be in an open state. The first switching device 221 and the second switching device 222 are brought into the open state and the third and fourth switching devices 223 and 224 are controlled to be in the closed state during the half period of the remaining resonance.

Through the above operation, an input voltage is applied to the second heating coil 242 and the third resonant capacitor 263 during the half period of the resonance, so that resonance starts and the current of the second heating coil 242 . An input voltage is applied to the second heating coil 242 and the third resonant capacitor 263 in reverse during a half period of the other resonance so as to start resonance so that the current in the opposite direction to the second heating coil 242 .

As the operation is repeated, the eddy current is induced in the cooking container placed on the second heating coil 242, so that the electromagnetic induction heating cooker operates.

Although it is not shown, when the third heating coil 243 is to be driven, the first, second and third switching devices 221, 222 and 223 are brought into a closed state during a half of the resonance period, and the fourth switching devices 224 Is in the open state. The first, second, and third switching devices 221, 222, and 223 are brought into the open state and the fourth switching devices 224 are controlled to be in the closed state during the half period of the remaining resonance.

Thus, the control unit 280 can drive the heating coil by controlling the switching elements.

As described above, the electromagnetic induction heating cooker according to the embodiment includes a plurality of heating coils and a minimum number of switching elements for driving the plurality of heating coils, thereby reducing the size of the electromagnetic induction heating cooker and reducing the production cost.

8 is a diagram showing signals for driving a plurality of heating coils in a time division manner in the embodiment of the present invention.

8, when the control unit 280 drives the first, second, and third heating coils 241, 242, and 243, the controller 280 first drives the first heating coil 241 and then drives the second heating coils 242 And drives the third heating coil 243 finally. By repeating this cycle, all of the first, second, and third heating coils 241, 242, and 243 can be driven.

First, when the control unit 280 attempts to drive the first heating coil 241, the first switching device 221 is closed for half a period of resonance, and the second, third, 222, 224 and 224 to be in the open state. Then, the first switching device 221 is brought into the open state and the second, third, and fourth switching devices 222, 223, and 224 are controlled to be in the closed state during the half period of the remaining resonance.

During the half period of the resonance through the above operation, an input voltage is applied to the first heating coil 241 and the first and second resonance capacitors 261 and 262, thereby starting resonance, The current rises. The input voltage is applied to the first heating coil 241 and the first and second resonant capacitors 261 and 262 in a half period of the other resonance, and resonance starts to be applied to the first heating coil 241 and the first heating coil 241 Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the first heating coil 241, so that the electromagnetic induction heating cooker operates.

Next, when the control unit 280 intends to drive the second heating coil 242, the first switching device 221 and the second switching device 222 are brought into a closed state during half the resonance period, And controls the third and fourth switching elements 223 and 224 to be in an open state. The first switching device 221 and the second switching device 222 are brought into the open state and the third and fourth switching devices 223 and 224 are controlled to be in the closed state during the half period of the remaining resonance.

Through the above operation, an input voltage is applied to the second heating coil 242 and the third resonant capacitor 263 during the half period of the resonance, so that resonance starts and the current of the second heating coil 242 . An input voltage is applied to the second heating coil 242 and the third resonant capacitor 263 in reverse during a half period of the other resonance so as to start resonance so that the current in the opposite direction to the second heating coil 242 .

As the operation is repeated, the eddy current is induced in the cooking container placed on the second heating coil 242, so that the electromagnetic induction heating cooker operates.

Similarly, when the third heating coil 243 is to be driven, the first, second, and third switching devices 221, 222, and 223 are brought into a closed state for half a period of resonance, and the fourth switching devices 224 are opened . The first, second, and third switching devices 221, 222, and 223 are brought into the open state and the fourth switching devices 224 are controlled to be in the closed state during the half period of the remaining resonance.

When all of the first, second, and third heating coils 241, 242, and 243 are driven in the above-described manner, all of the first, second, and third heating coils 241, 242, and 243 can be driven by driving again from the first heating coil 241 .

9 is a diagram showing signals for driving a plurality of heating coils in a duty control manner in the embodiment of the present invention.

9, when the control unit 280 drives all of the first, second and third heating coils 241, 242 and 243, the use of the first, second and third heating coils 241, 242 and 243 (for example, All of the first, second and third heating coils 241, 242 and 243 can be driven by duty control in accordance with a large-capacity cooking vessel or a small-capacity cooking vessel, Reduction can be compensated. Each of the first, second, and third heating coils 241, 242, and 243 is power-controlled through frequency control. If the output range is limited due to the frequency limitation, the duty can be compensated through the duty control.

9, the first heating coil 241 repeats four resonance cycles, the second heating coil 242 repeats two resonance cycles, and the third heating coil 243 repeats the resonance cycle four times, Repeat one resonance cycle.

Therefore, the first, second, and third heating coils 241, 242, and 243 may have different powers and be driven together according to their use or needs of the user.

10 is a diagram showing signals for driving two heating coils in a parallel driving manner in the embodiment of the present invention.

Referring to FIG. 10, when the control unit 280 simultaneously drives the second and third heating coils 242 and 243 in parallel, the third switching device 223 is brought into a closed state, The first and second switching elements 221 and 222 are brought into the closed state and the fourth switching element 224 is controlled in the open state. Then, the first and second switching devices 221 and 222 are brought into the open state and the fourth switching device 224 is controlled in the closed state during the half period of the remaining resonance.

Since the third switching device 223 is in a closed state, the second heating coil 242 and the third heating coil 243 are connected in parallel.

Accordingly, during the half period of the resonance through the above-described operation, the input voltage is applied to the second and third heating coils 242 and 243 and the third and fourth resonant capacitors 263 and 264, thereby starting resonance, The currents in the three heating coils 242 and 243 rise. The input voltage is applied to the second and third heating coils 242 and 243 and the third and fourth resonant capacitors 263 and 264 during the half period of the other resonance, The currents in the opposite direction to the currents 242 and 243 rise.

At this time, the second and third heating coils 242 and 243 operated by the parallel driving method can be formed with the same capacity. In the embodiment, the second and third heating coils 242 and 243 have a capacity of 1.8 kW .

In addition, the second and third heating coils 242 and 243 operated by the parallel driving method are preferably formed to have a smaller capacity than the first heating coils 241, respectively.

As the operation is repeated, the eddy current is induced in the cooking vessel placed on the second and third heating coils 242 and 243, and the electromagnetic induction heating cooker is operated.

The third resonant capacitor 263 connected to the second heating coil 242 is connected to the positive power terminal and the fourth resonant capacitor 243 connected to the third heating coil 243, 264 are connected to the negative power supply terminal, an overcurrent generated in the switching process of the switching elements 221, 222, 223, 224 can be branched so that the current ripple can be reduced and the heat generation can be reduced.

11 and 12 are views for explaining the change of the current flowing through the heating coil and the voltage across the DC capacitor according to the connection direction of the resonant capacitor in the embodiment of the present invention.

11 is a view illustrating a state where the second heating coil 242 and the third heating coil 243 are connected in parallel when the third resonant capacitor 263 and the fourth resonant capacitor 264 are connected to the negative power terminal, And the voltage 302 across the DC capacitor 290 are shown in Figure 12 and Figure 12 shows the third resonant capacitor 263 and the fourth resonant capacitor 264 respectively connected to the negative power terminal The current 301 flowing in the second heating coil 242 and the third heating coil 243 and the voltage 302 across the DC capacitor 290 in the parallel driving method are connected to the positive power terminal, .

As the conditions used in the experiment, two heating coils (21 turns, 36 strands), a gap of 4.5 mm, a half-bridge (HVIC driving) inverter, a Vf of 1.05 V and an IGBT , The vessel is a 9 "/ 7" Al-clad vessel, source (240V, 60Hz, using CVCF), 4700W for 30 minutes.

11 and 12, when the third resonant capacitor 263 and the fourth resonant capacitor 264 are connected to the negative power terminal and the positive power terminal, respectively, It can be seen that it is remarkably decreased.

In Fig. 11, the voltage across ripple of DC capacitor 290 is reduced to 20V in Fig. 12, while the voltage ripple across the both ends of DC capacitor 290 is 108V.

FIG. 13 is a view for explaining the temperature change of the heat generated in the bridge diode of the rectifying part according to the connection direction of the resonant capacitor in the embodiment of the present invention. FIG.

13, when the third resonant capacitor 263 and the fourth resonant capacitor 264 are both connected to the negative power terminal, the third resonant capacitor 263 and the fourth resonant capacitor 264 are connected in parallel to each other in the bridge diode of the rectifying unit 210 When the third resonance capacitor 263 and the fourth resonance capacitor 264 are connected to the negative power terminal and the positive power terminal respectively while the column 304 appears close to 90 ° C, It can be seen that the heat 305 generated in the bridge diode of the heat sink 210 does not exceed 80 캜.

As described above, according to the present invention, the third resonance capacitor 263 and the fourth resonance capacitor 264 are connected to the negative power terminal and the positive power terminal, respectively, so that the heat generated in the rectifier 210 can be significantly reduced have.

14 is a view for explaining a structure of an electromagnetic induction heating cooker according to another embodiment of the present invention.

Referring to FIG. 14, the electromagnetic induction heating cooker includes a rectifying unit 110 for receiving a commercial AC power from the outside and for rectifying the AC power to a DC power supply, a rectifying unit 110 for rectifying the rectified power, A second switching element 122, a third switching element 123, a fourth switching element 124, a fifth switching element 125, and a second switching element 125, which are connected in series to each other and are switched according to a control signal, A first resonant capacitor 161 having one end connected to a contact point between the first switching device 121 and the second switching device 122 and connected to one end and the other end of the rectifying part 110, One end of the rectifying part 110 is connected to the contact between the second switching device 122 and the third switching device 123 and the other end of the rectifying part 110 is connected to the first heating coil 141, And the other end between the third resonant capacitor 163 and the fourth resonant capacitor 164 connected to the other end And a fifth resonant capacitor 165 having one end connected to a contact point between the third switching device 123 and the fourth switching device 124 and the other end connected to the other end of the rectifying part 110, And a sixth heating coil 143 having one end connected to the contact point between the fourth switching device 124 and the fifth switching device 125 and the other end connected to the other end of the rectifying part 110, And a fourth heating coil 144 whose other end is connected to the resonance capacitor 166.

Further, although not shown, a control unit for controlling the switching operation of the switching elements 121, 122, 123, 124, and 125 is further included.

Although four heating coils are illustrated in the embodiment, the number of the heating coils may be three or more.

In the embodiment, when the number of the heating coils is N, N + 1 switching elements may be provided, and it is possible to drive the heating coils while minimizing the number of switching elements.

The first switching device 121 has one end connected to the positive power supply terminal and the other end connected to the second switching device 122. The second switching element 122 has one end connected to the first switching element 122 and the other end connected to the third switching element 123. The third switching device 123 has one end connected to the second switching device 122 and the other end connected to the fourth switching device 124. The fourth switching device 124 has one end connected to the third switching device 123 and the other end connected to the fifth switching device 125. The fifth switching device 125 has one end connected to the fourth switching device 124 and the other end connected to a negative power terminal.

The DC capacitor 190 may further include a DC capacitor 190 connected to both ends of the rectifying unit 110. The DC capacitor 190 reduces the ripple of the DC voltage output from the rectifying unit 110. [

Although the first heating coil 141 is connected between the first resonant capacitor 161 and the second resonant capacitor 162 in the embodiment, the first resonant capacitor 161 may not be provided have.

In the embodiment, the second heating coil 142 is connected between the third resonant capacitor 163 and the fourth resonant capacitor 164, but the third resonant capacitor 163 is not provided .

In the embodiment, the third heating coil 143 is connected to the fifth resonant capacitor 165 connected to the positive power terminal, and the fourth heating coil 144 is connected to the negative power terminal 6 resonator capacitor 166 but the third heating coil 143 is connected to the sixth resonant capacitor 166 connected to the negative power terminal and the fourth heating coil 144 is connected to the negative And may be connected to the fifth resonant capacitor 165 connected to the power supply terminal.

The third heating coil 143 and the fourth heating coil 144 may have the same capacity and the third heating coil 143 and the fourth heating coil 144 may be simultaneously driven in parallel .

When the third heating coil 143 and the fourth heating coil 144 are simultaneously driven in parallel, the switching elements 121, 122, 123, 124, and 125 operate as described below with reference to FIG. 22, Since the overcurrent generated in the section where the switches 121, 122, 123, 124 and 125 are closed (turned on) and the section that is opened (turned off) is branched to the positive power terminal and the negative power terminal, the instantaneous overcurrent section can be reduced.

If the fifth resonant capacitor 165 connected to the third heating coil 143 and the sixth resonant capacitor 166 connected to the fourth heating coil 144 are both the positive power terminal or the negative power terminal An overcurrent flows to the positive power terminal or the negative power terminal. As a result, when the third heating coil 143 and the fourth heating coil 144 are simultaneously driven in parallel, the current ripple is large and the rectifying unit 110 generates heat.

Accordingly, in the present invention, the fifth resonant capacitor 165 and the sixth resonant capacitor 166 are connected to the positive power terminal and the negative power terminal, respectively, thereby reducing the current ripple and reducing the heat generation.

An anti-parallel diode may be connected to the switching elements 121, 122, 123, 124, and 125, and an auxiliary resonance capacitor connected in parallel to the anti-parallel diode may be connected to minimize the switching loss of the switching elements.

FIG. 15 is a view illustrating a control unit for controlling a switching device according to another embodiment of the present invention, FIG. 16 is a view illustrating a gate driver for operating a switching device according to another embodiment of the present invention, and FIG. FIG. 4 is a diagram illustrating a switching mode power supply according to another embodiment of the present invention. FIG.

15 to 17, the controller 180 receives the inputs G1, G2, G3, G4 and G5 of the first, second, third, fourth and fifth gate drivers 191, 192, 193, 194 and 195 for driving the switching elements 121, G5 and GD5 of the gate drivers 191, 192, 193, 191 and 195 are connected to the gates of the switching elements 121, 122, 123, 124 and 125. The gates G1, GD2, GD3, GD4 and GD5 of the gate drivers 191, 17, independent power sources of the multiple output SMPS are used as power supplies to the gate drivers 191, 192, 193, 194, and 195, respectively.

Therefore, a signal of the controller 180 is applied to the gate drivers 191, 192, 193, 194, and 195 to control the respective switching elements 121, 122, 123, 124, and 125 by driving the semiconductor switches.

The current transformer 170 may be provided between the ground of the switching elements 121, 122, 123, 124 and 125 connected in series and the first, second, third and fourth heating coils 141, 142, 143 and 144, The current flowing through the first, second, third and fourth heating coils 141, 142, 143 and 144 is measured and inputted to the controller 180 via an analog-to-digital converter (ADC) provided in the controller 180. The controller 180 controls the switching elements 121, 122, 123, 124, and 125 based on the current value.

18 and 19 are diagrams showing signals for driving respective heating coils in another embodiment of the present invention.

As shown in FIGS. 18 and 19, the controller 180 controls currents flowing through the first, second, third, and fourth heating coils 141, 142, 143, and 144 by controlling the switching elements 121, 122, 123,

The control unit 180 causes the first switching device 121 to be in a closed state for half a period of resonance when the first heating coil 141 is to be driven, 122, 123, 124, 125 to be in the open state. Then, the first switching device 121 is brought into the open state and the second, third, fourth, and fifth switching devices 122, 123, 124, and 125 are controlled to be in the closed state during the half period of the remaining resonance.

The input voltage is applied to the first heating coil 141 and the first and second resonant capacitors 161 and 162 during the half period of the resonance through the above operation, The current rises. The input voltage is applied to the first heating coil 141 and the first and second resonant capacitors 161 and 162 during the half period of the rest of the resonance, Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the first heating coil 141, so that the electromagnetic induction heating cooker operates.

19, when the control unit 180 intends to drive the second heating coil 142, the first switching device 121 and the second switching device 122 are closed for half a period of the resonance, State, and controls the third, fourth, and fifth switching elements 123, 124, and 125 to be in an open state. The first switching device 121 and the second switching device 122 are brought into the open state and the third, fourth, and fifth switching devices 123, 124, and 125 are controlled to be in the closed state during the half period of the remaining resonance .

During the half period of the resonance through the above operation, the input voltage is applied to the second heating coil 142 and the third and fourth resonant capacitors 163 and 164 so that resonance starts and the second heating coil 142 The current rises. During the half period of the remaining resonance, the input voltage is applied to the second heating coil 142 and the third and fourth resonant capacitors 163 and 164 in reverse, thereby starting resonance, Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the second heating coil 142, and the electromagnetic induction heating cooker is operated.

Although not shown, when the third heating coil 143 is to be driven, the first, second and third switching devices 121, 122 and 123 are brought into a closed state during a half period of resonance, (124, 125) to be in the open state. During the half period of the remaining resonance, the first, second and third switching devices 121, 122 and 123 are brought into the open state and the fourth and fifth switching devices 124 and 125 are controlled to be in the closed state.

When the fourth heating coil 144 is to be driven, the first, second, third, and fourth switching devices 121, 122, 123, and 124 are closed for half a period of the resonance, and the fifth switching devices 125 To be in an open state. During the half period of the remaining resonance, the first, second, third, and fourth switching devices 121, 122, 123, and 124 are brought into the open state and the fifth switching devices 125 are controlled to be in the closed state.

In this way, the control unit 180 can drive the heating coil by controlling the switching elements.

As described above, the electromagnetic induction heating cooker according to the embodiment includes a plurality of heating coils and a minimum number of switching elements for driving the plurality of heating coils, thereby reducing the size of the electromagnetic induction heating cooker and reducing the production cost.

20 is a diagram showing signals for driving a plurality of heating coils in a time division manner in another embodiment of the present invention.

Referring to FIG. 20, the controller 180 drives the first heating coil 141 and then the second heating coil 142 when the first, second, and third heating coils 141, 142, And finally drives the third heating coil 143. In this case, By repeating this cycle, all of the first, second, and third heating coils 141, 142, and 143 can be driven.

First, when the control unit 180 desires to drive the first heating coil 141, the first switching device 121 is closed for half a period of resonance, and the second, third, Thereby controlling the switching elements 122, 123, 124, and 125 to be in an open state. Then, the first switching device 121 is brought into the open state and the second, third, fourth, and fifth switching devices 122, 123, 124, and 125 are controlled to be in the closed state during the half period of the remaining resonance.

The input voltage is applied to the first heating coil 141 and the first and second resonant capacitors 161 and 162 during the half period of the resonance through the above operation, The current rises. The input voltage is applied to the first heating coil 141 and the first and second resonant capacitors 161 and 162 during the half period of the rest of the resonance so that resonance starts to be applied to the first heating coil 141 Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the first heating coil 141, so that the electromagnetic induction heating cooker operates.

Next, when the controller 180 desires to drive the second heating coil 142, the first switching device 121 and the second switching device 122 are brought into the closed state during the half period of the resonance, And controls the third, fourth, and fifth switching elements 123, 124, and 125 to be in an open state. The first switching device 121 and the second switching device 122 are brought into the open state and the third, fourth, and fifth switching devices 123, 124, and 125 are controlled to be in the closed state during the half period of the remaining resonance .

During the half period of the resonance through the above operation, the input voltage is applied to the second heating coil 142 and the third and fourth resonant capacitors 163 and 164 so that resonance starts and the second heating coil 142 The current rises. During the half period of the remaining resonance, the input voltage is applied to the second heating coil 142 and the third and fourth resonant capacitors 163 and 164 in reverse, thereby starting resonance, Direction current is increased.

As the operation is repeated, the eddy current is induced in the cooking container placed on the second heating coil 142, and the electromagnetic induction heating cooker is operated.

Similarly, when the third heating coil 143 is to be driven, the first, second and third switching devices 121, 122 and 123 are brought into a closed state for half a period of resonance, and the fourth and fifth switching devices 124 and 125 To be in an open state. During the half period of the remaining resonance, the first, second and third switching devices 121, 122 and 123 are brought into the open state and the fourth and fifth switching devices 124 and 125 are controlled to be in the closed state.

When all of the first, second, and third heating coils 141, 142, and 143 are driven in the above-described manner, all of the first, second, and third heating coils 141, 142, and 143 can be driven by driving again from the first heating coils 141 .

21 is a diagram showing signals for driving a plurality of heating coils in a duty control manner in another embodiment of the present invention.

21, when the controller 180 drives all of the first, second and third heating coils 141, 142 and 143, the use of the first, second and third heating coils 141, 142, 143 (for example, All of the first, second and third heating coils 141, 142 and 143 can be driven by the duty control in accordance with the cooking capacity of the large capacity cooking vessel or the small capacity cooking vessel, Reduction can be compensated. Each of the first, second, and third heating coils 141, 142, and 143 may vary in power through frequency control. If the output range is limited due to frequency limitation, the duty can be compensated through such duty control.

21, the first heating coil 141 repeats four resonance cycles, the second heating coil 142 repeats two resonance cycles, and the third heating coil 143 repeats the resonance cycle four times, Repeat one resonance cycle.

Accordingly, the first, second, and third heating coils 141, 142, and 143 may have different powers and be driven together according to their use or needs of the user.

22 is a diagram showing signals for driving two heating coils in a parallel driving manner in another embodiment of the present invention.

22, when the control unit 180 simultaneously drives the third and fourth heating coils 143 and 144, the fourth switching device 124 is brought into a closed state, and during the half period of the resonance, 1,2,3 switching elements 121, 122 and 123 to be in the closed state and the fifth switching element 125 to be in the open state. Then, the first, second and third switching elements 121, 122 and 123 are brought into the open state and the fifth switching element 125 is controlled in the closed state during the half period of the remaining resonance.

Since the fourth switching device 124 is in the closed state, the third heating coil 143 and the fourth heating coil 144 are connected in parallel.

Accordingly, during the half period of the resonance through the above operation, the input voltage is applied to the third and fourth heating coils 143 and 144 and the fifth and sixth resonant capacitors 165 and 166, thereby starting resonance, The currents in the four heating coils 143 and 144 rise. The input voltage is applied to the third and fourth heating coils 143 and 144 and the fifth and sixth resonant capacitors 165 and 166 during a half period of the other resonance, The current in the opposite direction to the currents 143 and 144 rises.

In this case, the third and fourth heating coils 143 and 144 operated by the parallel driving method may have the same capacity. In the embodiment, the third and fourth heating coils 143 and 144 each have a capacity of 2.4 kW .

In addition, the third and fourth heating coils 143 and 144 operated by the parallel driving method are preferably formed to have a smaller capacity than the first and second heating coils 141 and 142, respectively.

As the operation is repeated, the eddy current is induced in the cooking vessel placed on the third and fourth heating coils 143 and 144, so that the electromagnetic induction heating cooker operates.

In the present invention, a fifth resonant capacitor 165 connected to the third heating coil 143 is connected to the positive power terminal and a sixth resonant capacitor (not shown) connected to the fourth heating coil 144, 166 are connected to the negative power supply terminal, an overcurrent generated in the switching process of the switching elements 121, 122, 123, 124, 125 can be branched so that current ripple and heat generation can be reduced.

110: rectification part 121, 122, 123, 124, 125:
141, 142, 143, 144:
161, 162, 163, 164, 165, 166: resonant capacitor
180:

Claims (10)

A rectifier for rectifying an input voltage to output a DC voltage;
A DC capacitor connected to both ends of the rectifying unit;
A plurality of switching elements for switching a DC voltage outputted through the rectifying part;
A plurality of heating coils heating the cooking vessel according to the control of the plurality of switching elements; And
And a control unit for controlling the plurality of switching elements,
Wherein the plurality of heating coils include a first heating coil, a second heating coil, and a third heating coil,
The other end of the resonant capacitor connected to the second heating coil is connected to one of the positive power terminal and the negative power terminal of the rectifying unit,
The other end of the resonant capacitor connected to the third heating coil is connected to the other of the positive power terminal and the negative power terminal of the rectifying unit,
Wherein the control unit controls the plurality of switching elements so that the second heating coil and the third heating coil are connected in parallel and simultaneously driven. The method according to claim 1,
Wherein the first heating coil has higher power consumption than the second heating coil or the third heating coil. 3. The method of claim 2,
Wherein the second heating coil and the third heating coil have the same power consumption. The method according to claim 1,
Wherein the plurality of switching elements includes a first switching element, a second switching element, a third switching element, and a fourth switching element,
Wherein the first heating coil is connected between the first switching device and the second switching device and the second heating coil is connected between the second switching device and the third switching device, 3 An electromagnetic induction heating cooker connected between a switching element and a fourth switching element. 5. The method of claim 4,
Wherein the control unit causes the third switching device to be closed to simultaneously drive the second heating coil and the third heating coil to cause the first and second switching devices to be in a closed state for half a period of resonance, So that the first and second switching elements are brought into the open state and the fourth switching element is brought into the closed state during the half period of the remaining resonance. A rectifier for rectifying an input voltage to output a DC voltage;
A DC capacitor connected to both ends of the rectifying unit;
A plurality of switching elements for switching a DC voltage outputted through the rectifying part;
A plurality of heating coils heating the cooking vessel according to the control of the plurality of switching elements; And
And a control unit for controlling the plurality of switching elements,
Wherein the plurality of heating coils includes a first heating coil, a second heating coil, a third heating coil, and a fourth heating coil,
The other end of the resonant capacitor connected to the third heating coil is connected to one of the positive power terminal and the negative power terminal of the rectifying unit,
The other end of the resonant capacitor connected to the fourth heating coil is connected to the other of the positive power terminal and the negative power terminal of the rectifying unit,
Wherein the control unit controls the plurality of switching elements so that the third heating coil and the fourth heating coil are connected in parallel and simultaneously driven. The method according to claim 6,
Wherein the first heating coil and the second heating coil have higher power consumption than the third heating coil or the fourth heating coil. 8. The method of claim 7,
Wherein the third heating coil and the fourth heating coil have the same power consumption as each other. The method according to claim 6,
Wherein the plurality of switching elements includes a first switching element, a second switching element, a third switching element, a fourth switching element, and a fifth switching element,
Wherein the first heating coil is connected between the first switching device and the second switching device and the second heating coil is connected between the second switching device and the third switching device, 3 switching element and the fourth switching element, and the fourth heating coil is connected between the fourth switching element and the fifth switching element. 10. The method of claim 9,
The control unit closes the fourth switching device to drive the third heating coil and the fourth heating coil in parallel, and causes the first, second, and third switching devices to be in a closed state during half the resonance period, 5 switching elements to be in the open state, and the first, second and third switching elements to be in the open state and the fifth switching element to be in the closed state during the half period of the remaining resonance.

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