KR102436144B1 - Induction heating device having improved target detection accuracy and, induction heating system comprising the same - Google Patents

Abstract

The present invention relates to an induction heating device with improved object detection accuracy and an induction heating system including the same. In addition, induction heating apparatus according to an embodiment of the present invention, a first working coil unit including a first and second working coils connected in parallel, performing a switching operation to provide a resonance current to at least one of the first and second working coils Turning on or off the first inverter unit applying The second semiconductor switch connected to the second working coil and the first inverter unit and the first and second semiconductor switches respectively control the operations of the first and second semiconductor switches to free resonance, and to generate a free resonance based on the number or frequency of pulses of the free resonance current. and a controller configured to detect which of the first and second working coils the object is located above the working coil.

Description

An induction heating device with improved object detection accuracy and an induction heating system including the same

The present invention relates to an induction heating device with improved object detection accuracy and an induction heating system including the same.

BACKGROUND ART Various types of cooking utensils are used to heat food at home or in a restaurant. Conventionally, a gas range using gas as a fuel has been widely used, but recently devices for heating an object to be heated, for example, a cooking vessel such as a pot, have been spread using electricity instead of gas.

A method of heating an object to be heated using electricity is largely divided into a resistance heating method and an induction heating method. The electrical resistance method is a method of heating an object to be heated by transferring heat generated when a current flows through a metal resistance wire or a non-metal heating element such as silicon carbide to the object to be heated through radiation or conduction. In addition, the induction heating method generates an eddy current in an object to be heated (eg, a cooking vessel) made of a metal component by using a magnetic field generated around the coil when high-frequency power of a predetermined size is applied to the coil. It is a method in which the heating object itself is heated.

Meanwhile, a technology for wirelessly supplying power has recently been developed and applied to many electronic devices. For electronic devices with wireless power transfer technology, the battery is charged simply by placing it on the charging pad without connecting a separate charging connector. Since the electronic device to which such wireless power transmission is applied does not require a wired cord or a charger, portability is improved, and its size and weight are reduced compared to the prior art.

Wireless power transmission technology largely includes an electromagnetic induction method using a coil, a resonance method using resonance, and a radio wave radiation method that converts electrical energy into microwaves and transmits them. Among them, the electromagnetic induction method is a technology for transmitting power using electromagnetic induction between a primary coil provided in a device for transmitting wireless power and a secondary coil provided in a device for receiving wireless power.

The induction heating method of the induction heating device as described above has substantially the same principle as the wireless power transmission technology by electromagnetic induction in that the object to be heated is heated by electromagnetic induction.

Accordingly, research and development of an induction heating device capable of selectively performing induction heating and wireless power transmission functions according to user needs are being actively conducted.

Such an induction heating device heats each of a plurality of objects (eg, a cooking vessel) or a working coil in a corresponding area to wirelessly transmit power to each of a plurality of objects (eg, a wireless power receiver). It is common to have

However, recently, an induction heating device that simultaneously heats one object with a plurality of working coils or wirelessly transmits power to one object through a plurality of working coils at the same time (ie, a zone-free type induction heating device) ) is widely used.

In the case of the zone-free type induction heating apparatus, in an area in which a plurality of working coils exist, the object may be induction heated or power may be wirelessly transmitted to the object regardless of the size and location of the object.

Here, referring to the PCT patent (WO2017/038014A1) and the US patent (US8742299B2), a conventional John-free type induction heating device is shown. let's see

1 and 2 are views illustrating a conventional induction heating apparatus of the zone-free method.

For reference, FIG. 1 is a view shown in the PCT patent (WO2017/038014A1), and FIG. 2 is a view shown in the US patent (US8742299B2).

First, referring to Figure 1, in the conventional induction heating device, when the user selects a wireless power transmission function, the communication unit in the induction heating device 2 to the control unit 18 wireless power transmission related information (for example, output, required coil size, etc.), and the control unit 18 determines whether the current coil 10' is heated or not and the temperature. Thereafter, a region in which the temperature of the coil 10 ′ is below a specific temperature is designated as a wireless power transmission region, and the region is displayed through the light emitting unit.

That is, there is a problem in that the user must place the wireless power receiving target 11 ′ in the corresponding position after confirming the position designated by the induction heating device 2 rather than the desired position in order to use the wireless power transmission function. This is because the conventional induction heating device 2 does not directly recognize the wireless power reception target 11 ′.

In addition, referring to FIG. 2 , in the case of the conventional induction heating apparatus, the presence or absence of the heating vessels R1 ′ to R3 ′ is determined based on the magnitude of the current flowing through each individual coil 11 (ie, RMS current). And, in the conventional induction heating device 10, if the current magnitude measured when the heating vessel is eccentric (that is, the heating vessel is disposed in the center of the coil) is at least 40% of the current magnitude when the heating vessel is eccentric, the corresponding coil heat up

However, in the case of a heating container, a difference occurs in the magnitude of the current due to the difference in coupling resistance depending on the presence/absence of the container. there is

In addition, Figure 3 is a block diagram illustrating a conventional zone-free system induction heating apparatus, as shown in Figure 3, the conventional zone-free system induction heating apparatus 9, a plurality of working coils (WC1 ~ WC4) Each of the plurality of working coils WC1 to WC4 has a structure in which individual relays (R1 to R4; for example, a 3-terminal relay) are connected to each of the plurality of working coils (WC1 to WC4) in order to independently classify and switch circuits for object detection. However, due to this structure, there is a problem that noise is generated during the switching operation of the relays R1 to R4.

In addition, when the object is positioned over different working coil groups (eg, WC1 to WC4), the first and second group relays 35 and 40 are provided for synchronization control of the working coils WC1 to WC4. All of them must be switched to be connected to the first inverter unit 25 or the second inverter unit 30 . However, even in this case, there is a problem in that noise is generated due to the switching operation of the group relay.

In addition, since the group relays 35 and 40, the individual relays R1 to R4, and the object detection circuit 45 provided for object detection occupy a significant portion of the circuit area, there is also a problem in that the circuit volume increases. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an induction heating device with improved object detection accuracy.

Another object of the present invention is to provide an induction heating device capable of solving a noise problem generated during a relay switching operation and reducing a circuit volume by eliminating a relay and an object detection circuit.

It is also another object of the present invention to provide an induction heating system having improved discrimination power of the wireless power receiving device of the above-described induction heating device.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned may be understood by the following description, and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the appended claims.

The induction heating apparatus according to the present invention may improve object detection accuracy by including a control unit that detects on which working coil the object is located on the basis of the number or frequency of pulses of the free resonant resonant current.

In addition, the induction heating apparatus according to the present invention performs the object detection operation using a semiconductor switch and a control unit instead of a relay and an object detection circuit, thereby solving a noise problem generated during a relay switching operation and reducing the circuit volume.

In addition, the induction heating system according to the present invention can improve the discrimination power of the wireless power receiver by maximizing the change in the inductance of the receiving end of the wireless power receiver.

The induction heating apparatus according to the present invention can improve the object detection speed and algorithm by independently dividing a plurality of working coils through a semiconductor switch and a control unit and turning on or off at high speed. In addition, based on the number of pulses of the free resonant resonant current, it detects the presence, center, or eccentricity of the container subject to induction heating, and detects the presence, center or eccentricity of the wireless power receiver based on the frequency of the free resonant resonant current. By doing so, the object detection accuracy may be improved. Furthermore, by notifying the user of whether the object is concentric or eccentric, the user can appropriately control the output of the induction heating device or the driven coil, etc., thereby improving the heating efficiency of the object to improve energy efficiency (or energy saving) This is possible. In addition, since an object detection operation is continuously performed on a working coil that is not driven, object detection reliability may be improved.

In addition, the induction heating device according to the present invention can solve the noise problem that occurs during the switching operation of the relay by performing the object detection operation using a semiconductor switch and a control unit instead of a relay and an object detection circuit, thereby improving user satisfaction. have. In addition, since the user can use it quietly even during a time period (eg, early morning or late at night) when the user is sensitive to noise problems, ease of use may be improved. In addition, the circuit volume can be reduced by eliminating the relay and the object detection circuit that take up a lot of volume in the circuit, and thus the overall volume of the induction heating device can be reduced. Furthermore, space utilization can be improved by reducing the overall volume of the induction heating device.

In addition, the induction heating system according to the present invention can improve the discrimination power of the wireless power receiver of the above-described induction heating device by maximizing the change in inductance through improvement of the circuit structure of the receiving end of the wireless power receiver. In addition, through this, wireless power transmission/reception efficiency and reliability may be improved.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 and 2 are views illustrating a conventional induction heating apparatus of the zone-free method.
3 is a block diagram illustrating a conventional induction heating apparatus of the John-free method.
4 is a block diagram illustrating an induction heating apparatus according to an embodiment of the present invention.
FIG. 5 is a circuit diagram specifically illustrating the induction heating device of FIG. 4 .
6 is a schematic diagram for explaining the arrangement of the working coil of FIG. 5 .
7 is a circuit diagram for explaining an optimal example of the induction heating device of FIG.
8 is a schematic diagram for explaining the arrangement of the working coil of FIG. 7 .
9 is a schematic diagram illustrating an example of a method for detecting an object of the induction heating apparatus of FIG. 7 .
10 is a schematic diagram illustrating another example of a method for detecting an object of the induction heating apparatus of FIG. 7 .
11 to 16 are schematic diagrams for specifically explaining a method of detecting an object of the induction heating apparatus described in FIGS. 9 and 10 .
17 is a block diagram illustrating an induction heating system according to another embodiment of the present invention.
18 is a circuit diagram illustrating an example of a receiving end of the apparatus for receiving power wirelessly of FIG. 17 .
19 is a circuit diagram illustrating another example of a receiving end of the apparatus for receiving wireless power of FIG. 17 .

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Hereinafter, an induction heating device according to an embodiment of the present invention will be described.

4 is a block diagram illustrating an induction heating apparatus according to an embodiment of the present invention.

Referring to FIG. 4 , the induction heating apparatus 1 according to an embodiment of the present invention includes a power supply unit 100 , a rectifier unit 150 , first and second inverter units IV1 and IV2 , a control unit 250 , and a second It may include first to fourth working coils WC1 to WC4 , first to eighth semiconductor switches S1 to S4 , an auxiliary power source 300 , and an input interface 350 .

For reference, the number of some components (eg, inverter unit, working coil, semiconductor switch, etc.) of the induction heating and wireless power transmission apparatus 1 shown in FIG. 4 may be changed.

The power supply unit 100 may output AC power.

Specifically, the power supply unit 100 may output AC power and provide it to the rectification unit 150 , and may be, for example, commercial power.

The rectifying unit 150 may convert the AC power supplied from the power supply unit 100 into DC power and supply it to at least one of the first inverter unit IV1 and the second inverter unit IV2 .

Specifically, the rectifier 150 may rectify the AC power supplied from the power source 100 and convert it into DC power.

For reference, although not shown in the drawings, the DC power rectified by the rectifying unit 150 may be provided to a filter unit (not shown), and the filter unit may remove an AC component remaining in the corresponding DC power. Also, the DC power rectified by the rectifier 150 may be provided to a DC link capacitor (not shown; a smoothing capacitor), and the DC link capacitor may reduce a ripple of the corresponding DC power.

As described above, the DC power rectified by the rectifying unit 150 and the filter unit (or DC link capacitor) may be supplied to at least one of the first and second inverter units IV1 and IV2.

The first inverter unit IV1 may apply a resonance current to at least one of the first and second working coils WC1 and WC2 by performing a switching operation.

Specifically, the switching operation of the first inverter unit IV1 may be controlled by the controller 250 . That is, the first inverter unit IV1 may perform a switching operation based on the switching signal received from the control unit 250 .

For reference, the first inverter unit IV1 may include two switching elements (not shown), and the two switching elements are alternately turned on and turned on by a switching signal provided from the controller 250 . may be turned off.

In addition, a high-frequency AC current (ie, a resonance current) may be generated by the switching operation of these two switching elements, and the generated high-frequency AC current is applied to at least one of the first and second working coils WC1 and WC2. can be

Similarly, the second inverter unit IV2 may apply a resonance current to at least one of the third and fourth working coils WC3 and WC4 by performing a switching operation.

Specifically, the switching operation of the second inverter unit IV2 may be controlled by the controller 250 . That is, the second inverter unit IV2 may perform a switching operation based on the switching signal received from the control unit 250 .

For reference, the second inverter unit IV2 may include two switching elements (not shown), and the two switching elements are alternately turned on and turned on by a switching signal provided from the controller 250 . may be turned off.

In addition, a high-frequency AC current (ie, a resonance current) may be generated by the switching operation of the two switching elements, and the generated high-frequency AC current is applied to at least one of the third and fourth working coils WC3 and WC4. can be

The controller 250 controls the operations of the first and second inverter units IV1 and IV2, the first to fourth detection units D1 to D4, and the first to fourth semiconductor switches S1 to S4, respectively. can

Specifically, the switching operations of the first and second inverter units IV1 and IV2 may be controlled according to the switching signal of the control unit 250 , and the first to fourth semiconductor switches ( S1 to S4) may be turned on or off sequentially or in a specific order or at the same time.

For example, when the first inverter unit IV1 is driven by the switching signal of the control unit 250 and the first semiconductor switch S1 is turned on by the control signal of the control unit 250, the first working coil ( A resonance current may be applied to WC1).

In this way, the object positioned above the first working coil WC1 may be heated by the resonance current applied to the first working coil WC1 , or power may be wirelessly transmitted to the object.

For reference, the controller 250 may generate various switching signals or control signals through a pulse width modulation (PWM) function.

In addition, the driving mode of the induction heating device 1, that is, the induction heating mode or the wireless power transmission mode by the control unit 250 can be controlled.

That is, when the driving mode of the induction heating device 1 is set to the wireless power transmission mode by the control unit 250, at least one of the first to fourth working coils WC1 to WC4 is driven to the object (not shown). It transmits power wirelessly.

On the other hand, when the driving mode of the induction heating device 1 is set to the induction heating mode by the controller 250, at least one of the first to fourth working coils WC1 to WC4 is driven to operate the object (not shown). will heat up

In addition, the control unit 250 may determine the number of working coils to be driven, and the transmission power amount or heating intensity of the induction heating device 1 may vary according to the number of driven working coils.

In addition, the controller 250 may determine which working coil to drive according to the position of the object, and may determine whether to synchronize switching signals between the working coils to be driven.

Then, the control unit 250 detects the resonance current flowing in the first to fourth working coils WC1 to WC4, and based on the number or frequency of pulses of the detected resonance current, the first to fourth working coils WC1 to WC4. It may be determined in which coil the object is located.

Also, the controller 250 may determine whether the object is a magnetic or non-magnetic one based on the resonance current detection value.

Specifically, when the object seated on the upper portion of the induction heating device 1 is a magnetic material, since a large amount of eddy current is induced from the working coil to the object and resonates, a relatively small resonance current flows through the working coil. However, when the object to be seated on the upper portion of the induction heating device 1 does not exist or is a non-magnetic material, the working coil does not resonate, so a relatively large resonance current flows through the working coil.

Accordingly, when the resonance current flowing through the working coil is smaller than a preset reference current, the controller 250 may determine the object as a magnetic material. Conversely, when the resonance current flowing through the working coil is greater than or equal to the preset reference current, the controller 250 may determine that the object is a non-magnetic material or that the object does not exist.

Of course, although not shown in the drawings, the induction heating apparatus 1 may further include a detection unit (not shown) for detecting a resonance current flowing through the working coil, and the detection unit may perform the above-described object detection function.

However, for convenience of description, in the embodiment of the present invention, the controller 250 performs the object detection function as an example.

The first and second working coils WC1 and WC2 may be connected in parallel to each other.

Specifically, the first and second working coils WC1 and WC2 may be connected in parallel to each other and receive a resonance current from the first inverter unit IV1 .

That is, when the driving mode of the induction heating device 1 is the induction heating mode, the high-frequency AC current applied from the first inverter unit IV1 to at least one of the first and second working coils WC1 and WC2 corresponds to An eddy current may be generated between the working coil and the object to heat the object.

In addition, when the driving mode of the induction heating device 1 is the wireless power transmission mode, the first inverter unit IV1 corresponds to the high-frequency AC current applied to at least one of the first and second working coils WC1 and WC2. A magnetic field may be generated in the working coil. Due to this, a current may also flow in a coil inside the object corresponding to the working coil, and the object may be charged by the current flowing in the coil inside the object.

Also, the first working coil WC1 may be connected to the first semiconductor switch S1 , and the second working coil WC2 may be connected to the second semiconductor switch S2 .

Accordingly, each working coil can be turned on or off at high speed by a corresponding semiconductor switch.

The third and fourth working coils WC3 and WC4 may be connected in parallel to each other.

Specifically, the third and fourth working coils WC3 and WC4 may be connected in parallel to each other and receive a resonance current from the second inverter unit IV2 .

That is, when the driving mode of the induction heating device 1 is the induction heating mode, the second inverter unit IV2 corresponds to the high-frequency AC current applied to at least one of the third and fourth working coils WC3 and WC4. An eddy current may be generated between the working coil and the object to heat the object.

In addition, when the driving mode of the induction heating device 1 is the wireless power transmission mode, the second inverter unit IV2 corresponds to the high-frequency AC current applied to at least one of the third and fourth working coils WC3 and WC4. A magnetic field may be generated in the working coil. Due to this, a current may also flow in a coil inside the object corresponding to the working coil, and the object may be charged by the current flowing in the coil inside the object.

Also, the third working coil WC3 may be connected to the third semiconductor switch S3 , and the fourth working coil WC4 may be connected to the fourth semiconductor switch S4 .

Accordingly, each working coil can be turned on or off at high speed by a corresponding semiconductor switch.

For reference, the meaning that the working coil is turned on or off by the semiconductor switch may mean that the flow of the resonance current applied from the inverter unit to the working coil is released or blocked by the semiconductor switch.

Meanwhile, the first to fourth semiconductor switches S1 to S4 are to be respectively connected to the first to fourth working coils WC1 to WC4 to turn on or turn off the first to fourth working coils WC1 to WC4, respectively. and may receive power from the auxiliary power source 300 .

Specifically, the first semiconductor switch S1 may be connected to the first working coil WC1 to turn on or off the first working coil WC1, and the second semiconductor switch S2 may be connected to the second working coil WC1 ( WC2) to turn on or turn off the second working coil WC2. In addition, the third semiconductor switch S3 may be connected to the third working coil WC3 to turn on or off the third working coil WC3 , and the fourth semiconductor switch S4 may be connected to the fourth working coil WC4 . may be connected to to turn on or turn off the fourth working coil WC4 .

In addition, the first and second semiconductor switches S1 and S2 are driven by the control unit 250 in synchronization with the first inverter unit IV1 so that an object is present on the first and second working coils WC1 and WC2 . It can be used to detect whether or not to control the output of the first and second working coils WC1 and WC2.

In addition, the third and fourth semiconductor switches S3 and S4 are driven by the control unit 250 in synchronization with the second inverter unit IV2 so that an object is present on the third and fourth working coils WC3 and WC4 . It can be used to detect whether or not to control the output of the third and fourth working coils WC3 and WC4.

For reference, the first to fourth semiconductor switches S1 to S4 may include, for example, static switches. Also, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar mode transistor (IGBT) may be applied to the first to fourth semiconductor switches S1 to S4 .

The auxiliary power source 300 may supply power to the first to fourth semiconductor switches S1 to S4 .

Specifically, the auxiliary power source 300 may have a single output structure (ie, one output stage). Accordingly, the auxiliary power source 300 may supply power to the first to fourth semiconductor switches S1 to S4 with a single output. In addition, the auxiliary power source 300 may reduce the number of pins required for connection with the first to fourth semiconductor switches S1 to S4 compared to other multi-output structures.

Of course, when the single output capacity is too large (that is, when it greatly deviates from the preset reference capacity), the auxiliary power source 300 has a dual output structure (each output stage divides a single output capacity into a capacity less than or equal to the preset reference capacity) output structure).

For reference, the auxiliary power source 300 may include, for example, a switched mode power supply (SMPS), but is not limited thereto.

The input interface 350 may receive an input from a user and provide the corresponding input to the controller 250 .

Specifically, the input interface 350 is a module for inputting a desired heating intensity or driving time of the induction heating device 1 by a user, and may be variously implemented as a physical button or a touch panel.

Also, the input interface 350 may include, for example, a power button, a lock button, a power level adjustment button (+, -), a timer adjustment button (+, -), a charging mode button, and the like.

The input interface 350 may provide the received input information to the controller 250 , and the controller 250 may drive the induction heating device 1 in various ways based on the input information provided from the input interface 350 . It can be, an example of which is as follows:

When the user touches the power button provided on the input interface 350 for a predetermined time in a state in which the induction heating device 1 is not driven, the driving of the induction heating device 1 may be started. Conversely, when the user touches the power button for a predetermined time while the induction heating device 1 is being driven, the driving of the induction heating device 1 may be terminated.

In addition, when the user touches the lock button for a certain period of time, operation of all other buttons may become impossible. Afterwards, when the user touches the lock button again for a predetermined period of time, all other buttons may be operated.

In addition, when the user touches the power level control buttons (+, -) in a state in which power is input, the current power level of the induction heating device 1 may be displayed as a number on the input interface 350 . In addition, by the touch of the power level control button (+, -), the control unit 250 can confirm that the driving mode of the induction heating device 1 is the induction heating mode. In addition, the control unit 250 may adjust the frequency for the switching operation of the first and second inverter units IV1 and IV2 to correspond to the input power level.

In addition, the user may set the driving time of the induction heating device 1 by touching the timer control buttons (+, -). The control unit 250 may end the driving of the induction heating device 1 when the driving time set by the user has elapsed.

At this time, when the induction heating device 1 operates in the induction heating mode, the driving time of the induction heating device 1 set by the timer control buttons (+, -) may be the heating time of the object. In addition, when the induction heating device 1 operates in the wireless power transmission mode, the driving time of the induction heating device 1 set by the timer control buttons (+, -) may be the charging time of the object.

On the other hand, when the user touches the charging mode button, the induction heating device 1 may be driven in a wireless power transmission mode.

In this case, the controller 250 may receive device information on the corresponding object through communication with the object seated in the driving area (ie, the upper part of the working coil). The device information transmitted from the object may include, for example, information such as a type of the object, a charging mode, and an amount of power required.

In addition, the controller 250 may determine the type of the object based on the received device information and determine the charging mode of the object.

For reference, the charging mode of the object may include a normal charging mode and a fast charging mode.

Accordingly, the control unit 250 may adjust the frequency of at least one of the first and second inverter units IV1 and IV2 based on the confirmed charging mode. For example, in the fast charging mode, the control unit 250 may adjust the frequency so that a larger resonance current is applied to the working coil according to the switching operation of the inverter unit.

Of course, the charging mode of the object may be input by the user through the input interface 350 .

For reference, when an object (eg, a wireless power receiving device) is detected, the controller 250 controls the input interface 350 to display the detection fact of the detected object and a wireless power transmission proposal for the corresponding object to the UI ( User Interface) can also be displayed. When the user provides an input instructing wireless power transmission to the corresponding object through the UI displayed on the input interface 350, the control unit 250 operates the induction heating device 1 in the wireless power transmission mode based on the input. can

As such, the induction heating device 1 according to an embodiment of the present invention may have the above-described characteristics and configuration.

Hereinafter, with reference to FIGS. 5 and 6 , the characteristics and configuration of the induction heating and wireless power transmission apparatus 1 described above will be described in more detail.

FIG. 5 is a circuit diagram specifically illustrating the induction heating and wireless power transmission apparatus of FIG. 4 . 6 is a schematic diagram for explaining the arrangement of the working coil of FIG. 5 .

For reference, the induction heating and wireless power transmission device shown in FIG. 5 has the same configuration and characteristics as the induction heating and wireless power transmission device shown in FIG. Change it to use.

First, referring to FIG. 5 , the induction heating device 1 according to an embodiment of the present invention includes a power supply unit 100 , a rectifier unit 150 , a DC link capacitor 200 , and first to third inverter units IV1 to IV3), first to third working coil units (AWC, BWC, CWC), first to third semiconductor switch units AS, BS, CS, control unit 250, auxiliary power source 300, input interface 350 ) may be included.

For reference, the number of the inverter unit, the working coil unit, the working coil, the semiconductor switch unit, and the semiconductor switch is not limited to the number shown in FIG. 5 and may be changed.

In addition, as shown in FIG. 6, only the working coil constituting half of the entire area (zone-free area) is shown in FIG. 5, and FIG. 5 is an additional inverter unit, a working coil unit, It may further include a working coil, a semiconductor switch unit, and a semiconductor switch.

However, for convenience of description, in the embodiment of the present invention, the inverter unit, the working coil unit, the working coil, the semiconductor switch unit, and the semiconductor switch of FIG. 5 will be described as examples.

Specifically, the power supply unit 100 may output AC power and provide it to the rectifying unit 150 , and the rectifying unit 150 converts the AC power supplied from the power supply unit 100 into DC power to the DC link capacitor 200 . can provide

Here, the DC link capacitor 200 may be connected in parallel with the rectifier 150 .

Specifically, the DC link capacitor 200 may be connected in parallel with the rectifier 150 to receive a DC voltage from the rectifier 150 . In addition, the DC link capacitor 200 may be, for example, a smoothing capacitor, thereby reducing the ripple of the received DC voltage.

For reference, in the case of the DC link capacitor 200 , a DC voltage is provided from the rectifying unit 150 . One end of the DC voltage is applied, and the other end may be grounded by a potential difference with the one end.

Also, the DC power (or DC voltage) rectified by the rectifier 150 and having a ripple reduced by the DC link capacitor 200 may be supplied to at least one of the first to third inverter units IV1 to IV3. .

Meanwhile, the first inverter part IV1 includes two switching elements SV1 and SV1', the second inverter part IV2 includes two switching elements SV2 and SV2', and the third inverter part (IV3) may include two switching elements (SV3, SV3').

In addition, the switching elements included in each of the inverter units IV1 to IV3 are alternately turned on and off by the switching signal provided from the control unit 250 to convert DC power into high-frequency AC current (ie, resonance current). and the converted high-frequency alternating current may be provided to the working coil.

For example, the resonance current converted by the switching operation of the first inverter unit IV1 may be provided to the first working coil unit AWC, and the resonance converted by the switching operation of the second inverter unit IV2 . The current may be provided to the second working coil unit BWC. Also, the resonance current converted by the switching operation of the third inverter unit IV3 may be provided to the third working coil unit CWC.

Of course, the resonance current generated by the first inverter unit IV1 may be applied to at least one of the working coils WC1 and WC2 (first and second working coils) included in the first working coil unit AWC, The resonance current generated by the second inverter unit IV2 may be applied to at least one of the working coils WC3 and WC4 (third and fourth working coils) included in the second working coil unit BWC. In addition, the resonance current generated by the third inverter unit IV3 may be applied to at least one of the working coils WC5 to WC6 (fifth and sixth working coils) included in the third working coil unit CWC.

Here, the working coils WC1 and WC2 included in the first working coil unit AWC are connected in parallel to each other, and the working coils WC3 and WC4 included in the second working coil unit BWC are also connected in parallel to each other. has been In addition, the working coils WC5 to WC6 included in the third working coil unit CWC are also connected in parallel to each other.

Accordingly, as shown in FIG. 6 , the working coils WC1 and WC2 included in the first working coil unit AWC may be grouped and disposed in the A region AR, and the second working coil unit BWC. The working coils WC3 and WC4 included in ) may be grouped and disposed in the B region BR. In addition, the working coils WC5 and WC6 included in the third working coil unit CWC may be grouped and disposed in the C region CR.

Of course, the working coil may be disposed in the remaining empty space, and the input interface 350 may also be disposed at a location other than the location shown in FIG. 6 .

Referring back to FIG. 5 , the first semiconductor switch unit AS is connected to the first working coil unit AWC, and the second semiconductor switch unit BS is connected to the second working coil unit BWC. The third semiconductor switch unit CS may be connected to the third working coil unit CWC.

Specifically, the first semiconductor switch unit AS includes two semiconductor switches S1 and S2 (first and second semiconductor switches), and each of the two semiconductor switches S1 and S2 includes a first working coil unit ( AWC) may be respectively connected to the two working coils WC1 and WC2 included to turn on or off the two working coils WC1 and WC2, respectively.

Here, one end of each of the two semiconductor switches S1 and S2 is connected to the two working coils WC1 and WC2, respectively, and the other end of each of the two semiconductor switches S1 and S2 is the DC link capacitor 200 . It may be connected to the other end (ie, the ground terminal).

In addition, the second semiconductor switch unit BS includes two semiconductor switches S3 and S4 (third and fourth semiconductor switches), and each of the two semiconductor switches S3 and S4 includes a second working coil unit BWC. It is connected to the two working coils WC3 and WC4 included in the , so that the two working coils WC3 and WC4 can be turned on or off, respectively.

Here, one end of each of the two semiconductor switches S3 and S4 is connected to the two working coils WC3 and WC4, respectively, and the other end of each of the two semiconductor switches S3 and S4 is the DC link capacitor 200 . It may be connected to the other end (ie, the ground terminal).

In addition, the third semiconductor switch unit CS includes two semiconductor switches S5 and S6, and each of the two semiconductor switches S5 and S6 includes two working coils included in the third working coil unit CWC. WC5 and WC6 may be respectively connected to turn on or off the two working coils WC5 and WC6, respectively.

Here, one end of each of the two semiconductor switches S5 and S6 is connected to the two working coils WC5 and WC6, respectively, and the other end of each of the two semiconductor switches S5 and S6 is the DC link capacitor 200 . It may be connected to the other end (ie, the ground terminal).

That is, the other end of all semiconductor switches of the first to third semiconductor switch units AS, BS, and CS may be connected to the other end (ie, ground terminal) of the DC link capacitor 200 , and through this, the auxiliary power source 300 ) can supply power to all semiconductor switches through one output stage.

For reference, when the semiconductor switch is connected between the inverter unit and the working coil unit, the emitters of each semiconductor switch float to each other and the number of output stages of the auxiliary power source 300 increases by the number of semiconductor switches. have. Also, due to this, the number of pins of the auxiliary power source 300 increases, and thus there is a problem in that the circuit volume increases.

On the other hand, as in an embodiment of the present invention, when all of the semiconductor switches are connected to the ground terminal (ie, the other end of the DC link capacitor 200 ), the emitters of the semiconductor switches are not floated and all can be common. have. Accordingly, the auxiliary power source 300 may supply power to all semiconductor switches through one output terminal. In addition, the number of pins of the auxiliary power source 300 may be reduced compared to a case in which the emitter of the semiconductor switch is floated, and further, the circuit volume may be reduced.

Of course, the other ends of all semiconductor switches may be connected to one end of the DC link capacitor 200 (ie, a portion to which a DC voltage is applied). Also, when the single output capacity of the auxiliary power source 300 is too large (that is, when it greatly deviates from the preset reference capacity), the other end of the semiconductor switches included in some semiconductor switch units is the other end of the DC link capacitor 200 (ie, the other end of the DC link capacitor 200 ). ground terminal), and the other end of the semiconductor switches included in the remaining semiconductor switch unit may be connected to one end (ie, a portion to which a DC voltage is applied) of the DC link capacitor 200 .

However, for convenience of description, in one embodiment of the present invention, all of the semiconductor switches are connected to the ground terminal (ie, the other terminal of the DC link capacitor 200) as an example.

For reference, the induction heating apparatus 1 may further include a resonance capacitor (eg, C) connected between the working coil and the semiconductor switch.

In the case of the resonance capacitor C, when a voltage is applied by the switching operation of the inverter unit (eg, the first inverter unit IV1), resonance starts. Also, when the resonance capacitor C resonates, the current flowing in the working coil (eg, WC1 ) connected to the resonance capacitor C increases.

Through such a process, an eddy current is induced into the object disposed on the working coil WC1 connected to the resonance capacitor C. Referring to FIG.

Meanwhile, the controller 250 may control the operations of the first to third inverter units IV1 to IV3 and the first to third semiconductor switch units AS, BS, and CS, respectively.

That is, the controller 250 may provide a switching signal to control the operation of each of the inverter units IV1 to IV3 , and may provide a control signal to control each of the semiconductor switches S1 to S6 . .

In addition, the control unit 250 detects a resonance current flowing in at least one of the working coils WC1 to WC6 included in the first to third working coil units AWC, BWC, and CWC, and the number of pulses of the detected resonance current or Based on the frequency, it may be determined on which working coil the object is located.

That is, the control unit 250 controls the operations of the first to third inverter units IV1 to IV3 and the semiconductor switches S1 to S6 included in the first to third semiconductor switch units AS, BS, and CS, respectively. It is possible to detect which of the working coils WC1 to WC6 included in the first to third working coil units AWC, BWC, and CWC by controlling the upper part of which the object is located.

Hereinafter, with reference to FIGS. 7 and 8 to describe in detail the method of detecting an object of the induction heating apparatus 1, an optimal example (ie, the best mode) of the induction heating and wireless power transmission apparatus 1 described above. mode)) will be explained first.

7 is a circuit diagram for explaining an optimal example of the induction heating device of FIG. 8 is a schematic diagram for explaining the arrangement of the working coil of FIG. 7 . 9 is a schematic diagram illustrating an example of a method for detecting an object of the induction heating apparatus of FIG. 7 . 10 is a schematic diagram illustrating another example of a method for detecting an object of the induction heating apparatus of FIG. 7 . 11 to 16 are schematic diagrams for specifically explaining a method of detecting an object of the induction heating apparatus described in FIGS. 9 and 10 .

For reference, the induction heating and wireless power transmission device shown in FIG. 7 has the same configuration and characteristics as the induction heating and wireless power transmission device shown in FIG. 4 , but the number and name of some components to explain an optimal example change to use it.

First, referring to FIG. 7 , an optimal example of the induction heating device 1 according to an embodiment of the present invention is a power supply unit 100 , a rectifier unit 150 , a DC link capacitor 200 , and first to third inverter units. (IV1 to IV3), first to third working coil units (AWC, BWC, CWC), first to third semiconductor switch units (AS, BS, CS), control unit 250, auxiliary power source 300, input It may include an interface 350 .

That is, in an optimal example of the induction heating and wireless power transmission device 1 according to an embodiment of the present invention, the first working coil unit AWC includes six working coils AWC1 to AWC6, and the second working coil unit AWC1 to AWC6. The coil unit BWC may include four working coils BWC1 to BWC4 , and the third working coil unit CWC may include six working coils CWC1 to CWC6 . In addition, according to the number of working coils, the first semiconductor switch unit AS includes six semiconductor switches AS1 to AS6, and the second semiconductor switch unit BS includes four semiconductor switches BS1 to BS4. , the third semiconductor switch unit CS may include six semiconductor switches CS1 to CS6.

Accordingly, as shown in FIG. 8 , the working coils AWC1 to AWC6 included in the first working coil unit AWC may be grouped and disposed in the A region AR, and the second working coil unit BWC. The working coils BWC1 to BWC4 included in ) may be grouped and disposed in the B region BR. In addition, the working coils CWC1 to CWC6 included in the third working coil unit CWC may be grouped and disposed in the C region CR.

Of course, the working coil may be disposed in the remaining empty space, and the input interface 350 may also be disposed at a location other than the location shown in FIG. 8 .

Here, an example of a method for detecting an object of the induction heating apparatus 1 will be described with reference to FIGS. 7 and 9 .

For reference, for convenience of description, a process of detecting an object in area A (AR of FIG. 4 ) in which the first working coil unit AWC is disposed will be exemplified. In addition, it is assumed that the first working coil unit AWC includes four working coils, and the first semiconductor switch unit AS includes four semiconductor switches AS1 to AS4 respectively connected to the four working coils. do.

First, referring to FIGS. 7 and 9 , the control unit 250 provides N pulses to the first inverter unit IV1 every preset period in order to detect the position of the object (where N is 1, 2, 3, and when N is 1, a one pulse shot may be provided to the first inverter unit IV1 as a switching signal).

The first inverter unit IV1 may be turned on and turned off in accordance with each of the N pulses provided from the control unit 250 , thereby generating free resonance in the circuit including the first working coil unit AWC. can

Here, when the control unit 250 provides continuous pulses (ie, 4 or more pulses) instead of N pulses, a problem in standby power may occur, and the control unit 250 periodically transmits N pulses. It is provided to the first inverter unit IV1.

For reference, for convenience of description, a case in which N pulses are one pulse (ie, a single pulse) will be described as an example.

The controller 250 may sequentially turn on or off the four semiconductor switches AS1 to AS4 according to each single pulse until the position of the object is detected.

That is, the control unit 250 turns on the first semiconductor switch AS1 at a first time point P1, and after turning on the first semiconductor switch AS1, a first delay for a predetermined time P1 to P1 ′. When , a single pulse may be provided to the first inverter unit IV1. Here, the reason for having the first delay elapsed time is that a certain time is required for stabilization after the first semiconductor switch AS1 is turned on.

Subsequently, after a single pulse is provided to the first inverter unit IV1 , a second delay for a predetermined time P1 ″ to P2 may pass again. Here, the reason for the second delay elapsed time is that a predetermined time is required for signal processing for a single pulse provided to the first inverter unit IV1 and for detecting an object.

When the object is not detected before the second time point P2, when a preset period has elapsed since the first time point P1, the first semiconductor switch AS1 is turned off at the second time point P2, and the second semiconductor switch ( After AS2 is turned on, a single pulse may be provided to the first inverter unit IV1 again.

Also, the controller 250 may sequentially repeat the above-described process for the third and fourth semiconductor switches AS3 and AS4 until an object is detected.

However, if the object is not detected before the third time point P3, the controller 250 turns off the fourth semiconductor switch AS4 at the third time point P3 and turns on the first semiconductor switch AS1 The above-described process may be repeated again by providing a single pulse to the first inverter unit IV1 again.

For reference, when a single pulse is provided to the first inverter unit IV1 after the first semiconductor switch AS1 is turned on, a resonance current flows only to the first working coil AWC1 . At this time, the controller 250 detects a resonance current flowing through the first working coil AWC1, and based on the number or frequency of pulses of the detected resonance current, whether the object is located on the first working coil AWC1 can be detected. .

To explain further, when an object (eg, a container for induction heating) is positioned on the first working coil (AWC1), the overall resistance may increase due to the resistance of the object, which causes the first working coil (AWC1) As the degree of attenuation of the flowing resonance current increases, the number of pulses of the resonance current may decrease.

Also, when an object (eg, a wireless power receiving device) is positioned on the first working coil AWC1 , the total inductance may increase due to the inductance of the object, which causes the first working coil AWC1 to The frequency of the flowing resonant current may be reduced.

The control unit 250 detects the resonance current flowing in the first working coil AWC1 as described above, and based on the number or frequency of pulses of the detected resonance current, it is possible to detect whether there is a type of object on the first working coil AWC1. have.

Specific details on this will be described later.

As described above, the controller 250 may sequentially detect whether an object is positioned with respect to the second to fourth working coils AWC2 to AWC4, and may continuously repeat this process.

In addition, the above-described object detection operation may be performed in the same manner not only in the first working coil unit AWC but also in the second and third working coil units BWC and CWC.

Next, another example of a method for detecting an object of the induction heating apparatus 1 will be described with reference to FIGS. 7 and 10 .

For reference, for convenience of description, a process of detecting an object in area A (AR of FIG. 8 ) in which the first working coil unit AWC is disposed will be exemplified. In addition, it is assumed that the first working coil unit AWC includes four working coils, and the first semiconductor switch unit AS includes four semiconductor switches AS1 to AS4 respectively connected to the four working coils. do.

7 and 10 , the controller 250 controls the first and second semiconductor switches at a fourth time point P4 when an object is detected above the first and second working coils AWC1 and AWC2, for example. After the AS1 and AS2 are turned on, a switching signal whose frequency and phase are adjusted to correspond to the power level (ie, heating intensity or power transmission amount) received from the user may be provided to the first inverter unit IV1 .

Through this, a resonant current may be applied to the first and second working coils AWC1 and AWC2, and an object located thereon may be inductively heated or may receive power wirelessly.

Of course, even at this time, the control unit 250 provides a switching signal to the first inverter unit IV1 when the third delay for a predetermined time (P4 to P4') elapses after turning on the first and second semiconductor switches AS1 and AS2. can do. Here, the reason for having the third delay elapsed time is that a predetermined time is required for stabilization after the first and second semiconductor switches AS1 and AS2 are turned on.

In addition, the control unit 250, the object (ie, the first and second working coils AWC1, AWC2) on top of the non-driven working coil (that is, the third working coil (AWC3) or the fourth working coil (AWC4)) It may be continuously detected whether an object other than the located object) is located.

That is, the controller 250 may stop providing the switching signal to the first inverter unit IV1 in order to detect whether another object is located above the working coil that is not driven.

Specifically, when the fourth delay for a predetermined period of time (P4'' to P5) elapses after the control unit 250 stops providing the switching signal to the first inverter unit IV1, a preset time (eg, At the same time as the start of P5~P7; the number of undriven working coils X the time corresponding to the preset period), the first and second semiconductor switches AS1 and AS2 are turned off, and the third semiconductor switch AS3 can be turned on . Thereafter, the controller 250 may provide a single pulse to the first inverter unit IV1 within a preset time.

Here, the reason for having the fourth delay elapsed time is that a predetermined time is required for a signal processing operation for the switching signal provided to the first inverter unit IV1.

For the same reason as described above, when the control unit 250 provides a single pulse to the first inverter unit IV1 within a preset time, there is a delay for the time of P5 to P5', P5'' to P6 before and after the time of providing it. can

Of course, the controller 250 may then turn off or turn on the third and fourth semiconductor switches AS3 and AS4 sequentially according to a preset period in the same manner as the above-described method in order to detect another object.

In addition, the control unit 250 controls the third working coil (AWC3) or the fourth working coil (AWC4) until another object is not detected in the upper part until the preset time period (eg, P5 ~ P7) ends, the preset time of Simultaneously with the termination (ie, the seventh time point P7 ), the fourth semiconductor switch AS4 may be turned off, and the first and second semiconductor switches AS1 and AS2 may be turned on. Thereafter, the controller 250 may provide the above-described switching signal to the first inverter unit IV1 again.

For reference, as shown in FIG. 10 , the third semiconductor switch AS3 is already turned off at the sixth time point P6 , and the switching signal provided to the first inverter unit IV1 after the seventh time point P7 . is a switching signal whose frequency and phase are adjusted to correspond to the power level received from the user.

As such, the controller 250 may continuously detect whether another object is located above the working coil that is not driven even after the object is detected.

Of course, the above-described object detection operation may be performed in the same manner not only in the first working coil unit AWC but also in the second and third working coil units BWC and CWC.

Here, with reference to FIGS. 11 to 16 , how the controller 250 distinguishes and detects an object based on the detected resonance current will be described.

First, referring to FIGS. 7 and 11 , the controller 250 detects a resonance current ( S100 ).

Specifically, the controller 250 may detect a resonance current flowing through the working coil (ie, a free resonance resonance current).

Thereafter, the controller 250 compares the number of pulses of the detected resonance current with the first reference number (S200).

Specifically, the control unit 250 may detect whether a container for induction heating is present in the object based on the number of pulses of the detected resonance current.

That is, as shown in FIG. 12 , for example, by the switching operation of the first inverter unit IV1 (that is, the switching elements SV1 and SV1' are alternately turned on and off), the first inductor ( L1 (eg, the working coil AWC1 of FIG. 7 ) may flow a free resonant resonant current. Accordingly, an induced current flows to the object T while a magnetic flux is generated between the conversion inductor L2 (ie, the second inductor) and the first inductor L1 of the object T; for example, a container for induction heating. , at this time, the degree of attenuation of the resonance current (ie, (parasitic resistance of R+L1)/(2*(L1+L2))) increases as the total resistance increases due to the equivalent resistance R of the object T do.

As such, when the degree of attenuation of the resonance current is increased, the number of pulses of the corresponding resonance current is reduced. The control unit 250 detects a change in the number of pulses of the resonance current to determine whether the object T is present, eccentric, or centered. can be detected.

For reference, in an embodiment of the present invention, a method of detecting the presence or absence of an object (T; that is, a container for induction heating) based on a change in the number of pulses of the resonance current, centeredness, or eccentricity has been described, but the present invention is not limited thereto . That is, based on the pulse width change of the free resonant resonant current, the presence of the object T (ie, the container for induction heating), whether the center of gravity or the eccentricity may be detected.

However, for convenience of explanation, in the embodiment of the present invention, the control unit 250 detects the presence, eccentricity, or eccentricity of the object (T; that is, the induction heating target container) based on the change in the number of pulses of the resonance current. will be described with an example.

Referring back to FIGS. 7, 11 and 13 , when the number of pulses of the detected resonance current is less than the first reference number, the control unit 250 may compare the number of pulses of the corresponding resonance current with the second reference number (S240). ).

For reference, in an embodiment of the present invention, 'more than' and 'exceed' may be used interchangeably, and 'less than' and 'less than' may also be used interchangeably. However, for convenience of explanation, in the embodiment of the present invention, only one expression of 'more than' and 'exceed' is selected and used, and only one expression of 'less than' and 'less than' is selected and used.

On the other hand, the second reference number (eg, three) may be a lower number than the first reference number, and when the number of pulses of the detected resonance current is less than the first reference number, the control unit 250 controls the It may be determined that the object is located on the upper part.

More specifically, when the number of pulses of the detected resonance current is less than the first reference number and greater than or equal to the second reference number, the controller 250 may determine that the object is eccentrically located on the upper part of the corresponding working coil (S243) .

Also, when the number of pulses of the detected resonance current is less than the second reference number, the control unit 250 may determine that the object is centered on the upper portion of the corresponding working coil (S246).

For reference, the meaning that the object is eccentrically positioned on the upper part of the working coil may mean that it is positioned over only a part of the working coil rather than the exact center of the working coil. Also, the meaning that the object is centered on the upper part of the working coil may mean that it is positioned at the exact center of the working coil.

Meanwhile, when the number of pulses of the detected resonance current is equal to or greater than the first reference number, the controller 250 may compare the frequency of the resonance current with the first reference frequency ( S220 ).

Specifically, the controller 250 may detect whether the wireless power receiver is present among the object based on the frequency of the detected resonance current.

That is, as shown in FIG. 14, for example, by the switching operation of the first inverter unit IV1 (that is, the switching elements SV1 and SV1' are alternately turned on and off), the first inductor ( L1 (eg, the working coil AWC1 of FIG. 7 ) may flow a free resonant resonant current. Accordingly, electromagnetic induction occurs between the receiving end working coil L2 (ie, the second inductor) and the first inductor L1 of the object T; while the frequency (1/√((L1+L2)*C)) of the resonance current decreases.

As such, when the frequency of the resonance current is reduced, the controller 250 may detect whether the object T is present, eccentric, or centered by detecting a change in the frequency of the resonance current.

Referring back to FIGS. 7, 11 and 15 , when the frequency of the detected resonance current is the first reference frequency, the controller 250 may determine that the object does not exist above the corresponding working coil (S230). ).

Here, the first reference frequency may be, for example, a specific frequency used when generating a corresponding resonance current, but is not limited thereto. That is, it may be a frequency predefined by the user.

On the other hand, when the detected frequency of the resonance current is not the first reference frequency, the controller 250 may compare the frequency of the resonance current with the second reference frequency ( S260 ).

For reference, the second reference frequency may be a lower frequency than the first reference frequency, and when the frequency of the detected resonance current is less than the first reference frequency, the controller 250 determines that the object is located above the corresponding working coil. can do.

More specifically, when the frequency of the detected resonant current is less than the first reference frequency and greater than or equal to the second reference frequency, the controller 250 may determine that the object is eccentrically positioned above the corresponding working coil ( S263 ).

Also, when the frequency of the detected resonant current is less than the second reference frequency, the controller 250 may determine that the object is centered on the working coil ( S266 ).

As described above, the control unit 250 may detect the presence or absence of the induction heating target container based on the number of pulses of the detected resonance current and whether the vessel is concentric or eccentric, and based on the frequency of the detected resonance current, the wireless power receiver It is possible to detect the presence or absence of a mind or an eccentricity.

Accordingly, when the object T is disposed at the position shown in FIG. 16 , the controller 250 determines that the object T is centered in AWC3 and AWC4, eccentric in AWC1, AWC2, AWC5, AWC6, and CWC1 , it may be determined that the object does not exist in CWC3 and CWC5.

As described above, the induction heating device 1 according to an embodiment of the present invention has a plurality of working coils (AWC1 to AWC6) through the semiconductor switches (AS1 to AS6, BS1 to BS4, CS1 to CS6) and the control unit 250 . , BWC1 to BWC4, CWC1 to CWC6) can be independently classified and turned on or off at high speed to improve the object detection speed and algorithm. In addition, based on the number of pulses of the free resonant resonant current, it is detected whether the container to be induction heating is present, centered or eccentric, and based on the frequency of the free resonant resonant current, whether the wireless power receiver exists, centered or eccentric is detected By doing so, the object detection accuracy may be improved. Furthermore, since an object detection operation is continuously performed even for a working coil that is not driven, object detection reliability may be improved.

In addition, the induction heating device 1 according to the present invention uses the semiconductor switches (AS1 to AS6, BS1 to BS4, CS1 to CS6) and the control unit 250 instead of the relay and the object detection circuit to perform the object detection operation, thereby switching the relay It is possible to solve the noise problem generated during operation, thereby improving user satisfaction. In addition, since the user can use it quietly even during a time period (eg, early morning or late at night) when the user is sensitive to noise problems, ease of use may be improved. In addition, it is possible to reduce the circuit volume by removing the relay and the object detection circuit that occupy a large amount of volume in the circuit, thereby reducing the overall volume of the induction heating device 1 . Furthermore, space utilization can be improved by reducing the overall volume of the induction heating device 1 .

Hereinafter, an induction heating system according to another embodiment of the present invention will be described with reference to FIGS. 17 to 19 .

For reference, the induction heating apparatus 1 shown in FIG. 17 is the same as the induction heating apparatus 1 described above in FIGS. 4 to 16 , and a description thereof will be omitted.

First, referring to FIG. 17 , an induction heating system 1000 according to another embodiment of the present invention may include an induction heating device 1 and a wireless power receiving device 500 .

Specifically, the wireless power receiving device 500 may be provided with a working coil at the receiving end inside.

Accordingly, power may be supplied to the wireless power receiver 500 through electromagnetic induction generated between the corresponding working coil and the working coil provided in the induction heating device 1 .

Here, referring to FIGS. 17 and 18 , an example of a receiving end of the wireless power receiving apparatus 500 is illustrated.

Specifically, a relay (R; or a switch) may be located at the receiving end of the wireless power receiving apparatus 500 . In addition, as shown in FIG. 18 in order to show only the second inductor L2 at the receiving end of the wireless power receiving device 500, the relay R may be switched so that the receiving end maintains a short state. Accordingly, the inductance value of the wireless power receiving apparatus 500 may be maximized.

For this reason, the control unit (250 in FIG. 7) of the induction heating device 1, the resonance current (that is, the induction heating device 1) that fluctuates greatly as the inductance value of the wireless power receiving device 500 is maximized It is possible to easily detect the frequency of the resonance current flowing in the provided working coil), and furthermore, it is possible to easily detect whether the wireless power receiver 500 exists, eccentricity, or eccentricity.

Of course, when the control unit ( 250 of FIG. 7 ) detects the existence of the wireless power receiving device 500 and then the power of the wireless power receiving device 500 is driven, the relay R is switched to be connected to the capacitor C′. can be Accordingly, the wireless power receiving device 500 may be in a state that can receive power from the induction heating device (1).

Meanwhile, referring to FIGS. 17 and 19 , another example of a receiving end of the wireless power receiving apparatus 500 is illustrated.

Specifically, unlike FIG. 18 , a third inductor L3 in addition to the second inductor L2 may be additionally provided at the receiving end of the wireless power receiving apparatus 500 . The inductance value may be further maximized.

Accordingly, the control unit (250 in FIG. 7) of the induction heating device 1, the resonance current (that is, the induction heating device 1) that fluctuates greatly as the inductance value of the wireless power receiving device 500 is maximized It is possible to more easily detect the frequency of the resonance current flowing in the provided working coil), and further, it is possible to more easily detect whether the wireless power receiver 500 is present, eccentricity, or eccentricity.

As described above, the induction heating system 1000 according to another embodiment of the present invention receives wireless power of the induction heating device 1 by maximizing the change in inductance through improvement of the circuit structure of the receiving end of the wireless power receiving device 500 . Device discrimination can be improved. In addition, through this, efficiency and reliability of wireless power transmission/reception may be improved.

For those of ordinary skill in the art to which the present invention pertains, various substitutions, modifications and changes are possible within the scope of the present invention without departing from the technical spirit of the present invention. is not limited by

100: power unit 150: rectification unit
200: DC link capacitor 250: control unit
300: auxiliary power 350: input interface

Claims (12)

a first working coil unit including first and second working coils connected in parallel;
an inverter unit for applying a resonance current to at least one of the first and second working coils by performing a switching operation;
a first semiconductor switch coupled to the first working coil for turning on or off the first working coil;
a second semiconductor switch connected to the second working coil for turning on or off the second working coil; and
includes a control unit,
The control unit is
applying the resonance current to the first working coil and the second working coil by controlling the operation of the inverter unit and the first and second semiconductor switches, respectively;
Identifies the number or frequency of pulses for the resonance current applied to the first working coil and the second working coil,
Detecting which of the first and second working coils the object is located on the upper part of the working coil based on the identified number or frequency of pulses,
The control unit is
Based on the identified number of pulses, it is determined that the object is a container for induction heating,
Based on the identified frequency, determining that the object is a wireless power receiving device
induction heating device.
According to claim 1,
The control unit is
Provide N pulses (N is any one of 1, 2, 3) to the inverter unit at a preset period to detect the position of the object,
Turning on or off the first and second semiconductor switches sequentially and repeatedly in accordance with the N pulses until the position of the object is detected
induction heating device.
3. The method of claim 2,
The control unit is
After turning on the first semiconductor switch at a first time point, the N pulses are provided to the inverter unit,
Detecting whether the object is positioned above the first working coil based on the number of pulses or the frequency of the resonance current free resonating from the first time point to a second time point at which the preset period has elapsed,
Turning off the first semiconductor switch at the second time point, turning on the second semiconductor switch, and then providing the N pulses back to the inverter unit
induction heating device.
4. The method of claim 3,
The control unit detects whether the object is located above the second working coil based on the number or frequency of the pulses of the free resonant resonant current from the second time point to a third time point when the preset period has elapsed, ,
Turning off the second semiconductor switch at the third time point, turning on the first semiconductor switch, and then providing the N pulses back to the inverter unit
induction heating device.
4. The method of claim 3,
The control unit is
When the number of pulses of the free resonant resonant current is equal to or greater than the first reference number and the frequency of the free resonant resonant current is the first reference frequency from the first time point to the second time point at which the preset period has elapsed Determining that the object is not located above the first working coil
induction heating device.
6. The method of claim 5,
The control unit is
When the number of pulses of the free resonant resonant current is less than the first reference number and greater than or equal to the second reference number, it is determined that the object is eccentrically located on the upper portion of the first working coil,
When the number of pulses of the free resonant resonant current is less than the second reference number, it is determined that the object is centered on the upper portion of the first working coil.
induction heating device.
6. The method of claim 5,
The control unit is
When the frequency of the free resonant resonant current is less than the first reference frequency and greater than or equal to the second reference frequency, it is determined that the object is eccentrically located on the upper portion of the first working coil,
When the frequency of the free resonant resonant current is less than the second reference frequency, it is determined that the object is centered on the upper part of the first working coil.
induction heating device.
4. The method of claim 3,
When a first delay elapses after the first semiconductor switch is turned on at the first time point, the N pulses are provided to the inverter unit,
When a second delay elapses after the N pulses are provided to the inverter unit, the first semiconductor switch is turned off at the second time point.
induction heating device.
3. The method of claim 2,
When the control unit detects the object from the upper part of the first working coil,
providing a switching signal whose frequency and phase are adjusted to correspond to the power level input from the user to the inverter unit, and turning on or off the first semiconductor switch in accordance with the switching signal
induction heating device.
10. The method of claim 9,
The control unit is
Stop providing the switching signal to the inverter unit to detect whether an object other than the object is located above the second working coil;
Turning off the first semiconductor switch and turning on the second semiconductor switch simultaneously with the start of a preset time after stopping the supply of the switching signal;
providing the N pulses to the inverter unit within the preset time after turning on the second semiconductor switch
induction heating device.
11. The method of claim 10,
The control unit detects whether the other object is located above the second working coil based on the number of pulses or the frequency of the resonant current that resonates freely before the preset time expires,
Turning off the second semiconductor switch and turning on the first semiconductor switch at the same time as the end of the preset time,
providing the switching signal back to the inverter unit after turning on the first semiconductor switch
induction heating device.
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