Patent Application
20160374155
The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2015-0088600 (filed on Jun. 22, 2015), which is hereby incorporated by reference in its entirety.
In general, an induction heat cooking apparatus is an electric cooking apparatus for performing a cooking function by passing high-frequency current through a working coil or a heating coil and heating a cooking utensil by eddy current flowing when a strong line of magnetic force generated by the high-frequency current passes through the cooking utensil.
In the basic heating principle of the induction heat cooking apparatus, the cooking utensil which is a magnetic body generates heat by induction heating as current is applied to a heating coil, and the cooking utensil itself is heated by the generated heat, thereby cooking food.
An inverter used for the induction heat cooking apparatus serves to switch a voltage applied to the heating coil such that high-frequency current flows in the heating coil. The inverter drives a switching element generally composed of an insulated gate bipolar transistor (IGBT) such that high-frequency current flows in the heating coil, thereby forming a high-frequency magnetic field in the heating coil.
When the induction heat cooking apparatus includes two heating coils, two inverters including four switching elements are required to operate the two heating coil.
Referring to
In the first and second inverters 20 and 30, two switching elements for switching input voltages are connected in series and first and second heating coils 40 and 50 driven by the output voltages of the switching elements are connected to the contact points of the switching elements connected in series. The other sides of the first and second heating coils 40 and 50 are connected to the resonance capacitors 60 and 70.
The switching elements are driven by a drive unit and are alternately switched at switching times output from the drive unit, thereby applying high-frequency voltages to the heating coils. Since the on/off times of the switching elements driven by the drive unit are controlled to be gradually compensated for, the voltage supplied to the heating coil is changed from a low voltage to a high voltage.
However, the induction heat cooking apparatus includes two inverter circuits including four switching elements in order to operate two heating coils. Therefore, the volume and price of a product increase.
When the number of heating coils is three or more, the number of switching elements increases according to the number of heating coils.
In addition, there is a need for a method of efficiently discharging heat generated in a plurality of switching elements and a bridge diode.
An object of an embodiment of the present invention is to provide an electronic induction heat cooking apparatus having a plurality of heating coils, which is capable of being controlled using a minimum number of switching elements, and a method of controlling the same.
Another object of the present invention is to provide an electronic induction heat cooking apparatus having a plurality of heating coils simultaneously driven using a minimum number of switching elements, and a method of controlling the same.
Another object of the present invention is to provide an electronic induction heat cooking apparatus capable of efficiently radiating heat generated in a plurality of switching elements and a bridge diode.
An electronic induction heat cooking apparatus according to the present invention includes a heat sink having a plurality of switching elements mounted thereon; a cover covering the plurality of switching elements; and coupling members for coupling the heat sink and the cover. A radiation fin for cooling the plurality of switching elements is formed on the cover.
In order to increase a contact area between the plurality of switching elements and the heat sink, the coupling members may be coupled to the heat sink through the cover and the switching elements.
In order to improve cooling efficiency of a cooling fan, the radiation fin formed on the cover may be formed in a direction parallel to a discharge direction of air discharged from the cooling fan. In addition, the bridge diode and the plurality of switching elements may be arranged in a direction parallel to the discharge direction of air discharged from the cooling fan.
In addition, the bridge diode for generating relatively large amounts of heat may be provided closer to the cooling fan than the plurality of switching elements.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.
Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.
Also, in the description of embodiments, terms such as first, second, A, B, (a), (b) or the like may be used herein when describing components of the present invention. Each of these terminologies is not used to define an essence, order or sequence of a corresponding component but used merely to distinguish the corresponding component from other component(s). It should be noted that if it is described in the specification that one component is “connected,” “coupled” or “joined” to another component, the former may be directly “connected,” “coupled,” and “joined” to the latter or “connected”, “coupled”, and “joined” to the latter via another component.
Referring to
In addition, although not shown, a controller for controlling switching operations of the switching elements 221, 222, 223 and 224 is further included. In the embodiment, three heating coils are included.
In the embodiment, when the number of heating coils is N, N+1 switching elements may be included and the heating coils may be driven while minimizing the number of switching elements.
One end of the first switching element 221 is connected to the positive voltage terminal and the other end thereof is connected to the second switching element 222. One end of the second switching element 222 is connected to the first switching element 221 and the other end thereof is connected to the third switching element 223. One end of the third switching element 223 is connected to the second switching element 222 and the other end thereof is connected to the fourth switching element 224. One end of the fourth switching element 224 is connected to the third switching element 223 and the other end thereof is connected to the negative voltage terminal.
In addition, a DC capacitor 290 connected across the rectifier 210 may be further included and the DC capacitor 290 reduces ripple of a DC voltage output from the rectifier 210.
Although, in the embodiment, the first heating coil 241 is connected between the first resonance capacitor 261 and the second resonance capacitor 262, the first resonance capacitor 261 may not be included.
Although, in the embodiment, the second heating coil 242 is connected to the third resonance capacitor 263, the second heating coil may be connected between an additional resonance capacitor (not shown) and the third resonance capacitor 263, similarly to the first heating coil 241.
Although, in the embodiment, the third heating coil 243 is connected to the fourth resonance capacitor 264, the third heating coil may be connected between an additional resonance capacitor (not shown) and the fourth resonance capacitor 264, similarly to the first heating coil 241.
In the switching elements 221, 222, 223 and 224, an anti-parallel diode may be connected and an auxiliary resonance capacitor connected to the anti-parallel diode in parallel may be connected to minimize switching loss of the switching elements.
In the present invention, the switching elements 221, 222, 223 and 224 may be arranged in a first direction. A cooling fan 295 is provided at one side of the switching elements 221, 222, 223 and 224 such that air from the cooling fan 295 flows in the first direction.
That is, since the switching elements 221, 222, 223 and 224 are arranged in a line on the flow channel of air discharged from the cooling fan 295, it is possible to improve cooling efficiency of the switching elements 221, 222, 223 and 224.
The first switching element 221 may be provided closest to the cooling fan 295 and then the second switching element 222, the third switching element 223 and the fourth switching element 224 may be arranged.
The first heating coil 241 is connected between the first switching element 221 and the second switching element 222, the second heating coil 242 is connected between the second switching element 222 and the third switching element 223, and the third heating coil 243 is connected between the third switching element 223 and the fourth switching element 224.
The power of the first heating coil 241 may be greater than that of the second heating coil 242 or the third heating coil 243 and the power of the second heating coil 242 may be equal to that of the third heating coil 243. In the embodiment, the power of the first heating coil 241 may be 4.4 kW and the power of the second heating coil 242 and the third heating coil 243 may be 1.8 kW.
Referring to
The mounting surface may be formed at an angle with respect to a radiation fin provided on the heat sink 205. Accordingly, the cooling efficiency of the switching elements 221, 222, 223 and 224 provided on the mounting surface can be improved.
The heat sink 205 may include the radiation fin formed thereon. The radiation fin formed on the heat sink 205 may be formed in a direction parallel to the discharge direction of air discharged from the cooling fan 295.
On the mounting surface of the heat sink 205, a bridge diode 211 of the rectifier 210 is provided in addition to the switching elements 221, 222, 223 and 224. The switching elements may be arranged in a line and the bridge diode 211 may be arranged in a line with the switching elements 221, 222, 223 and 224.
In the present invention, the switching elements 221, 222, 223 and 224 are arranged on the mounting surface of the heat sink 205 and a cover 206 is provided on the switching elements 221, 222, 223 and 224, and the switching elements 221, 222, 223 and 224 are fixed to the heat sink 205 by coupling members 207 along with the cover 206. For example, each coupling member 207 may be a screw.
The radiation fin for cooling the switching elements 221, 222, 223 and 224 may be formed on the cover 206. The radiation fin formed on the cover 206 may be formed in a direction parallel to the discharge direction of air discharged from the cooling fan 295. Thus, since a flow channel may be formed toward the radiation fin formed on the cover 206, it is possible to improve the radiation effect of the switching elements 221, 222, 223 and 224.
In addition, the cover 206 may pressurize the switching elements 221, 222, 223 and 224 to increase a contact area between the switching elements 221, 222, 223 and 224 and the heat sink 205. Accordingly, it is possible to improve cooling efficiency of the switching elements 221, 222, 223 and 224.
The cover 206 is formed with a length capable of covering all the switching elements 221, 222, 223 and 225 and is provided to at least partially overlap the heat sink 205 in a vertical direction.
In addition, the cover 206 may be formed with a length capable of covering the switching elements 221, 222, 223 and 224 and the bridge diode 211.
The coupling members 207 are coupled to the heat sink 205 through the cover 206, the switching elements 221, 222, 223 and 224 and the bridge diode 211.
The coupling members 207 are individually provided in correspondence with the switching elements 221, 222, 223 and 224 and the bridge diode 211.
The cooling fan 295 is provided adjacent to the bridge diode 211 and the first switching element 221. Since the bridge diode 211 generates more heat than the first switching element 221, the bridge diode may be provided closer to the cooling fan 295 than the first switching element 221.
When the bridge diode 211, the switching elements 221, 222, 223 and 224, the cover 206 and the cooling fan 295 are provided, it is possible to efficiently reduce the amount of heat generated in the switching elements 221, 222, 223 and 224.
Referring to
Accordingly, the signal from the controller 280 is applied to the gate drivers 291, 292, 293 and 294 to drive the semiconductor switches, thereby controlling the switching elements 221, 222, 223 and 224.
A current converter 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 current converter 270 measures current flowing in the first, second and third heating coils 241, 242 and 243 such that a current value is input to the controller 280 through an analog/digital converter (ADC) included in the controller 280. The controller 280 controls the switching elements 221, 222, 223 and 224 based on the current value.
As shown in
When driving the first heating coil 241, the controller 280 controls the first switching element 221 to be closed and controls the second, third and fourth switching elements 222, 223 and 224 to be opened during a half resonance period. During the remaining half resonance period, the controller controls the first switching element 221 to be opened and controls the second, third and fourth switching elements 222, 223 and 224 to be closed.
Through the above operation, during the half resonance period, an input voltage is applied to the first heating coil 241 and the first and second resonance capacitors 261 and 262 and thus resonance starts to increase current of the first heating coil 241. During the remaining half resonance period, the input voltage is reversely applied to the first heating coil 241 and the first and second resonance capacitors 261 and 262 and thus resonance starts to increase reverse current of the first heating coil 241.
As operation is repeated, eddy current is induced in the cooking utensil laid on the first heating coil 241 to operate the electronic induction heat cooking apparatus.
As shown in
Through the above operation, during the half resonance period, an input voltage is applied to the second heating coil 242 and the third resonance capacitor 263 and thus resonance starts to increase current of the second heating coil 242. During the remaining half resonance period, the input voltage is reversely applied to the second heating coil 242 and the third resonance capacitor 263 and thus resonance starts to increase reverse current of the second heating coil 242.
As operation is repeated, eddy current is induced in the cooking utensil laid on the second heating coil 242 to operate the electronic induction heat cooking apparatus.
Although not shown, when the third heating coil 243 is driven, during a half resonance period, the first, second and third switching elements 221, 222 and 223 are controlled to be closed and the fourth switching element 224 is controlled to be opened. During the remaining half resonance period, the first, second and third switching elements 221, 222 and 223 are controlled to be opened and the fourth switching element 224 is controlled to be closed.
The controller 280 controls the switching elements in this manner to drive the heating coils.
As described above, the electronic induction heat cooking apparatus 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 decreasing the size of the electronic induction heat cooking apparatus and reducing production costs.
Referring to
First, when driving the first heating coil 241, the controller 280 controls the first switching element 221 to be closed and controls the second, third and fourth switching elements 222, 223 and 224 to be opened during a half resonance period. During the remaining half resonance period, the controller controls the first switching element 221 to be opened and controls the second, third and fourth switching elements 222, 223 and 224 to be closed.
Through the above operation, during the half resonance period, an input voltage is applied to the first heating coil 241 and the first and second resonance capacitor 261 and 262 and thus resonance starts to increase current of the first heating coil 241. During the remaining half resonance period, the input voltage is reversely applied to the first heating coil 241 and the first and second resonance capacitor 261 and 262 and thus resonance starts to increase reverse current of the first heating coil 241.
As operation is repeated, eddy current is induced in the cooking utensil laid on the first heating coil 241 to operate the electronic induction heat cooking apparatus.
Subsequently, when driving the second heating coil 242, the controller 280 controls the first switching element 221 and the second switching element 222 to be closed and controls the third and fourth switching elements 223 and 224 to be opened during a half resonance period. During the remaining half resonance period, the controller controls the first switching element 221 and the second switching element 222 to be opened and controls the third and fourth switching elements 223 and 224 to be closed.
Through the above operation, during the half resonance period, an input voltage is applied to the second heating coil 242 and the third resonance capacitor 263 and thus resonance starts to increase current of the second heating coil 242. During the remaining half resonance period, the input voltage is reversely applied to the second heating coil 242 and the third resonance capacitor 263 and thus resonance starts to increase reverse current of the second heating coil 242.
As operation is repeated, eddy current is induced in the cooking utensil laid on the second heating coil 242 to operate the electronic induction heat cooking apparatus.
Similarly, when the third heating coil 243 is driven, during a half resonance period, the first, second and third switching elements 221, 222 and 223 are controlled to be closed and the fourth switching element 224 is controlled to be opened. During the remaining half resonance period, the first, second and third switching elements 221, 222 and 223 are controlled to be opened and the fourth switching element 224 is controlled to be closed.
When the first, second and third heating coils 241, 242 and 243 are all driven using the above-described method, the first, second third heating coils 241, 242 and 243 may be driven again starting from the first heating coil 241.
Referring to
As shown in
Accordingly, the first, second and third heating coils 241, 242 and 243 may be driven together, with different powers according to use thereof or user's need.
Referring to
Since the third switching element 223 remains in the closed state, the second heating coil 242 and the third heating coil 243 are connected in parallel.
Accordingly, through the above operation, during the half resonance period, an input voltage is applied to the second and third heating coils 242 and 243 and the third and fourth resonance capacitors 263 and 264 and thus resonance starts to increase current in the second and third heating coils 242 and 243. During the remaining half resonance period, an input voltage is reversely applied to the second and third heating coils 242 and 243 and the third and fourth resonance capacitors 263 and 264 and thus resonance starts to increase reverse current in the second and third heating coils 242 and 243.
At this time, the second and third heating coils 242 and 243 operating using the parallel driving method have the same power. In the embodiment, the power of the second and third heating coils 242 and 243 is 1.8 kW.
In addition, the power of the second and third heating coils 242 and 243 operating using the parallel driving method may be less than that of the first heating coil 241.
As operation is repeated, eddy current is induced in the cooking utensil laid on the second and third heating coils 242 and 243 to operate the electronic induction heat cooking apparatus.
In
As shown in
In contrast, as shown in
In the present invention, it is possible to rapidly radiate heat of the switching element through the cover 206.
The embodiment of the present invention provides an electronic induction heat cooking apparatus having a plurality of heating coils, which is capable of being controlled using a minimum number of switching elements, and a method of controlling the same.
In addition, the embodiment of the present invention provides an electronic induction heat cooking apparatus having a plurality of heating coils simultaneously driven using a minimum number of switching elements, and a method of controlling the same.
In addition, the embodiment of the present invention provides an electronic induction heat cooking apparatus capable of efficiently radiating heat generated in a plurality of switching elements and a bridge diode.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2015-0088600 | Jun 2015 | KR | national |
