KR102182624B1 - Induction heat cooking apparatus and method for driving the same - Google Patents

Abstract

The electromagnetic induction heating cooker according to the embodiment comprises: a rectifier configured to rectify an input voltage and output a DC voltage; A plurality of switching elements by switching the DC voltage output through the rectifier; A plurality of heating coils for heating the cooking vessel under the control of the switching device; A current converter disposed between the grounds of the plurality of switching elements and the plurality of heating coils; And a controller for controlling a plurality of switching elements according to the current values sensed through the current converter.

Description

The electromagnetic induction heating cooker and its driving method {INDUCTION HEAT COOKING APPARATUS AND METHOD FOR DRIVING THE SAME}

The present invention relates to an electromagnetic induction heating cooker, and more particularly, to an electromagnetic induction heating cooker comprising a plurality of switching elements and a plurality of resonance circuits, and a driving method thereof.

In general, induction heating cookers allow high-frequency current to flow through a working coil or a heating coil, and when a strong magnetic line of force generated by this flows through the cooking vessel, eddy current flows and the vessel itself is heated. It is an electric cooking device that performs a cooking function by a method.

Looking at the basic heating principle of such an induction heating cooker, as a current is applied to the heating coil, the magnetic cooking vessel generates heat by induction heating, and the cooking vessel itself is heated by the heat generated in this way, so that cooking is not possible. Will come true.

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 made of 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 such an induction heating cooker, two inverters formed of four switching elements are required to operate the two heating coils.

1 is a diagram illustrating an induction heating cooker according to the prior art.

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

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

In the first and second inverters 20 and 30, two switching elements for switching input power are connected in series, and the first and second heating coils 40 and 50 driven by the output voltage of the switching element are connected in series. It is connected to the connection point of a series-connected switching element. Further, the other side of the first and second heating coils 40 and 50 is connected to the resonance capacitors 60 and 70.

The switching element is driven by the driving unit, and is controlled by the switching time output from the driving unit, so that the switching elements alternately operate with each other and a high-frequency voltage is applied to the heating coil. In addition, since the on/off time of the switching element applied from the driving unit is gradually compensated, the voltage supplied to the heating coil changes from a low voltage to a high voltage.

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

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

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

An object of the present invention is 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 equipped with a plurality of heating coils, and a control method thereof.

An embodiment of the present invention is an electromagnetic induction heating capable of sensing the current flowing through a plurality of heating coils through a single current converter in an electromagnetic induction heating cooker equipped with a plurality of heating coils and controlling the output of the plurality of heating coils accordingly. It is an object to provide a cooker and a control method thereof.

The electromagnetic induction heating cooker according to the embodiment comprises: a rectifier configured to rectify an input voltage and output a DC voltage; A plurality of switching elements by switching the DC voltage output through the rectifier; A plurality of heating coils for heating the cooking vessel under the control of the switching device; A current converter disposed between the grounds of the plurality of switching elements and the plurality of heating coils; And a control unit controlling a plurality of switching elements according to the current values sensed through the current converter.

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

An embodiment 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 including a plurality of heating coils, and a control method thereof.

An embodiment of the present invention is an electromagnetic induction heating capable of sensing the current flowing through a plurality of heating coils through a single current converter in an electromagnetic induction heating cooker equipped with a plurality of heating coils and controlling the output of the plurality of heating coils accordingly. A cooker and a control method thereof can be provided.

1 is a diagram illustrating an induction heating cooker according to the prior art.
2 is a diagram illustrating a structure of an electromagnetic induction heating cooker according to an embodiment of the present invention.
3 is a view showing a control unit for controlling the switching device, FIG. 4 is a view showing a gate driver that operates the switching device, and FIG. 5 is a view showing a switching mode power supply.
6 and 7 are diagrams showing signals for driving respective heating coils in the present invention.
8 is a diagram showing a signal for driving a plurality of heating coils in a time division manner in the present invention.
9 is a diagram showing a signal for driving a plurality of heating coils in a duty control method in 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 is a diagram illustrating a structure of an electromagnetic induction heating cooker according to an embodiment of the present invention.

Referring to FIG. 2, in the electromagnetic induction heating cooker, commercial AC power is input from the outside, and a rectifier 110 for rectifying the AC power to DC power, and both ends of the positive and negative power terminals of the rectifying unit 110. The first switching device 121, the second switching device 122, the third switching device 123, the fourth switching device 124, and the fifth switching device 125 are connected in series to each other and are switched according to the control signal. ), and a first resonant capacitor 161 and a second resonant capacitor, 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 unit 110 (162) One end is connected to a first heating coil 141 connected to the other end, and a contact point between the second switching element 122 and the third switching element 123, and one end of the rectifying unit 110 and A second heating coil 142 connected to the other end between the third resonant capacitor 163 and the fourth resonant capacitor 164 connected to the other end, and between the third switching device 123 and the fourth switching device 124 A third heating coil 143 having one end connected to the contact point of and the other end connected between the fifth resonance capacitor 165 connected to the other end of the rectifier 110, the fourth switching element 124 and the fifth switching A fourth heating coil 144 having one end connected to the contact point between the elements 125 and the other end connected between the sixth resonance capacitor 166 connected to the other end of the rectifying unit 110 is included.

In addition, although not shown, a controller for controlling the switching operation of the switching elements 121, 122, 123, 124, 125 is further included.

In the embodiment, it is illustrated that four heating coils are provided, but three or more heating coils may be provided.

In an embodiment, when the number of 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 terminal and the other end connected to the second switching device 122. The second switching device 122 has one end connected to the first switching device 122 and the other end connected to the third switching device 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. One end of the fourth switching device 124 is connected to the third switching device 123 and the other end of the fourth switching device 124 is 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 sub power terminal.

In addition, a smoothing capacitor 190 connected to both ends of the rectifying unit 110 may be further included, and the smoothing capacitor 190 allows the ripple of the DC voltage output from the rectifying unit 110 to be reduced.

In an embodiment, it is illustrated that the first heating coil 141 is connected between the first resonance capacitor 161 and the second resonance capacitor 162, but the first resonance capacitor 161 may not be provided. have.

Further, in an embodiment, it is illustrated that the second heating coil 142 is connected between the third resonance capacitor 163 and the fourth resonance capacitor 164, but the third resonance capacitor 163 is not provided. May not.

In addition, in an embodiment, although the third heating coil 143 is illustrated to be connected to the fifth resonance capacitor 165, in a manner similar to the first heating coil 141 or the second heating coil 142, It is also possible to connect between the additional resonance capacitor and the fifth resonance capacitor (165) not shown.

In addition, in the embodiment, although the fourth heating coil 144 is illustrated to be connected to the sixth resonance capacitor 166, in a manner similar to the first heating coil 141 or the second heating coil 142, It is also possible to be connected between an additional resonant capacitor not shown and the sixth resonant capacitor 166.

The switching elements 121, 122, 123, 124, 125 may be connected with an anti-parallel diode, and an auxiliary resonant capacitor connected in parallel to the anti-parallel diode may be connected to minimize switching losses of the switching elements.

3 is a view showing a control unit for controlling the switching device, FIG. 4 is a view showing a gate driver operating the switching device, and FIG. 5 is a view showing a switching mode power supply.

3 to 5, the controller 180 includes inputs (G1, G2, G3, G4) of the 1st, 2nd, 3rd, 4th, 5th gate drivers 191, 192, 193, 194, 195 driving the switching elements 121, 122, 123, 124, 125 G5), and the outputs GD1, GD2, GD3, GD4, GD5 of the gate drivers 191,192,193,194,195 are connected to the gate terminals of the switching devices 121,122,123,124,125. And, as shown in FIG. 5, the power supplied to the gate drivers 191, 192, 193, 194, 195 is an independent power source of a multiple output SMPS.

Accordingly, a signal from the controller 180 is applied to the gate drivers 191, 192, 193, 194, and 195 to drive the semiconductor switch, thereby controlling the respective switching elements 121, 122, 123, 124, and 125.

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

For example, when driving the first heating coil 141, the controller 180 may measure the current flowing through the first heating coil 141 through the current value measured by the current converter 170. I can.

In addition, when the first heating coil 141 and the second heating coil 142 are driven in a time-division manner, the controller 180 controls the current converter 170 when each of the heating coils 141 and 142 is driven. By measuring the current value measured at, the current flowing through each of the first heating coil 141 and the second heating coil 142 can be measured.

Through this, the controller 180 may control the output of the first, second, third, and fourth heating coils 141, 142, 143, and 144.

6 and 7 are diagrams showing signals for driving respective heating coils in the present invention.

6 and 7, the controller 180 controls the switching elements 121, 122, 123, 124, and 125 to control the current flowing through the first, second, third, and fourth heating coils 141, 142, 143, and 144.

When the control unit 180 intends to drive the first heating coil 141, the first switching device 121 is in a closed state during a half cycle of resonance, and the second, third, fourth, and fifth switching devices They are controlled to be in the open state (122, 123, 124, 125). In addition, the first switching device 121 is opened during the remaining half cycle of the resonance, and the second, third, fourth, and fifth switching devices 122, 123, 124 and 125 are controlled to be closed.

During the half cycle of resonance through the above-described operation, an input voltage is applied to the first heating coil 141 and the first and second resonance capacitors 161 and 162, and accordingly, the resonance starts and the first heating coil 141 is The current rises. And, during the remaining half cycle of the resonance, the input voltage is reversely applied to the first heating coil 141 and the first and second resonance capacitors 161 and 162, and accordingly, the resonance starts and the opposite of the first heating coil 141 The direction current rises.

As such an operation is repeated, an eddy current is induced to facilitate cooking placed on the first heating coil 141, so that the electromagnetic induction heating cooker operates.

As shown in FIG. 7, when the controller 180 intends to drive the second heating coil 142, the first switching device 121 and the second switching device 122 are closed during a half cycle of resonance. And the third, fourth, and fifth switching elements 123, 124 and 125 are controlled to be open. In addition, the first switching element 121 and the second switching element 122 are in an open state during the remaining half cycle of the resonance, and the third, fourth, and fifth switching elements 123, 124, and 125 are controlled to be in a closed state. .

During the half cycle of resonance through the above-described operation, an input voltage is applied to the second heating coil 142 and the third and fourth resonance capacitors 163 and 164, and accordingly, the resonance starts and the second heating coil 142 is The current rises. In addition, the second heating coil 142 and the third and fourth resonance capacitors (163, 164) during the remaining half cycle of the resonance input voltage is applied in reverse, and accordingly, the resonance starts and the opposite of the second heating coil 142 The direction current rises.

As such an operation is repeated, a eddy current is induced to facilitate cooking placed on the second heating coil 142, so that the electromagnetic induction heating cooker operates.

Although not shown, when the third heating coil 143 is to be driven, the first, second, and third switching elements 121, 122, and 123 are closed during a half cycle of resonance, and the fourth and fifth switching elements (124,125) is controlled to be open. The first, second, and third switching elements 121, 122, and 123 are opened and the fourth and fifth switching elements 124 and 125 are controlled to be closed during the remaining half cycle of the resonance.

In addition, when the fourth heating coil 144 is to be driven, the first, second, third, and fourth switching elements 121, 122, 123 and 124 are closed during a half cycle of resonance, and the fifth switching elements 125 are closed. Control to be open. The first, second, third, and fourth switching elements 121, 122, 123, and 124 are in an open state during the remaining half cycle of the resonance, and the fifth switching elements 125 are controlled to be in a closed state.

As described above, the controller 180 may 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 production cost.

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

Referring to FIG. 8, when the controller 180 intends to drive the first, second, and third heating coils 141, 142, and 143, it first drives the first heating coil 141, and then the second heating coil 142. ), and finally, the third heating coil 143 is driven. In addition, by repeating such one cycle, all of the first, second, and third heating coils 141, 142, and 143 may be driven.

First, when the controller 180 wants to drive the first heating coil 141, the first switching device 121 is closed during a half cycle of resonance, and the second, third, fourth, fifth The switching elements 122,123,124,125 are controlled to be in an open state. In addition, the first switching device 121 is opened during the remaining half cycle of the resonance, and the second, third, fourth, and fifth switching devices 122, 123, 124 and 125 are controlled to be closed.

During the half cycle of resonance through the above-described operation, an input voltage is applied to the first heating coil 141 and the first and second resonance capacitors 161 and 162, and accordingly, the resonance starts and the first heating coil 141 is The current rises. And, during the remaining half cycle of the resonance, the input voltage is reversely applied to the first heating coil 141 and the first and second resonance capacitors 161 and 162, and accordingly, the resonance starts and the opposite of the first heating coil 141 The direction current rises.

As such an operation is repeated, an eddy current is induced to facilitate cooking placed on the first heating coil 141, so that the electromagnetic induction heating cooker operates.

Subsequently, when the controller 180 intends to drive the second heating coil 142, the first switching element 121 and the second switching element 122 are closed during a half cycle of resonance, and the The third, fourth, and fifth switching elements 123, 124, and 125 are controlled to be in an open state. In addition, the first switching element 121 and the second switching element 122 are in an open state during the remaining half cycle of the resonance, and the third, fourth, and fifth switching elements 123, 124, and 125 are controlled to be in a closed state. .

During the half cycle of resonance through the above-described operation, an input voltage is applied to the second heating coil 142 and the third and fourth resonance capacitors 163 and 164, and accordingly, the resonance starts and the second heating coil 142 is The current rises. In addition, the second heating coil 142 and the third and fourth resonance capacitors (163, 164) during the remaining half cycle of the resonance input voltage is applied in reverse, and accordingly, the resonance starts and the opposite of the second heating coil 142 The direction current rises.

As such an operation is repeated, a eddy current is induced to facilitate cooking placed on the second heating coil 142, so that the electromagnetic induction heating cooker operates.

Likewise, in the case of driving the third heating coil 143, the first, second, and third switching elements 121, 122, and 123 are in a closed state during a half cycle of resonance, and the fourth and fifth switching elements 124 and 125 are Control to be open. The first, second, and third switching elements 121, 122, and 123 are opened and the fourth and fifth switching elements 124 and 125 are controlled to be closed during the remaining half cycle of the resonance.

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

9 is a diagram showing a signal for driving a plurality of heating coils in a duty control method in the present invention.

9, when the control unit 180 drives all of the first, second, and third heating coils 141, 142, and 143, the purpose of the first, second, and third heating coils 141, 142, 143 (for example, It is possible to drive all of the first, second, and third heating coils 141, 142 and 143 by controlling the duty according to (for a large-capacity cooking container or a small-capacity cooking container), and power The reduction can be compensated. The power of each of the first, second, and third heating coils 141, 142, and 143 is changed through frequency control, and when there is a limitation in the output range due to frequency limitation, compensation may be performed through such duty control.

As shown in Fig. 9, the first heating coil 141 repeats four resonance cycles, the second heating coil 142 repeats two resonance cycles, and the third heating coil 143 Repeat one resonance cycle.

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

110: rectifying unit 121,122,123,124,125: switching device
141,142,143,144: heating coil
161,162,163,164,165,166: resonant capacitor
180: control unit

Claims (1)

A rectifier for rectifying the input voltage and outputting a DC voltage;
A plurality of switching elements for switching the DC voltage output through the rectifier;
A plurality of heating coils for heating the cooking vessel under the control of the switching element;
A current converter disposed between the grounds of the switching elements and the grounds of the heating coils to measure currents flowing through each of the plurality of heating coils when the plurality of heating coils are driven in a time division manner; And
An electromagnetic induction heating cooker comprising a control unit for controlling a plurality of switching elements according to a current value sensed through the current converter.

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