Power conversion device and household appliance having the same

Abstract

The present invention relates to a power conversion device and a household appliance having the same. The power conversion device of an embodiment of the present invention includes a first capacitor storing a first voltage, a first switching element turned on to output the first voltage stored in the first capacitor to a first node which is one end of an inductive load, a second switching element connected to the first switching element at one end and turned on to cause the voltage of the first node to drop to the first voltage, a third switching element turned on to output a second voltage greater than the first voltage to the first node which is one end of the inductive load, and a fourth switching element connected to one end of the third switching element and turned on to cause the voltage of the first node to drop to a ground voltage. Thus, switching loss when power is supplied to the inductive load can be reduced.

Description

Technical Field

[0001] The present invention relates to a power conversion device and a household appliance having the same, and more specifically, to a power conversion device and a household appliance having the same capable of reducing switching losses when supplying power to an inductive load. Background Technology

[0002] A power conversion device is a device that converts input power and supplies the converted power to the load.

[0003] On the one hand, when the load is an inductive load, single-ended resonant inverters and half-bridge resonant inverters are used as power conversion devices.

[0004] However, when using single-ended resonant inverters and half-bridge resonant inverters, the operating frequency is low, resulting in large sizes of resonant capacitors and resonant inductors.

[0005] In addition, due to the high internal pressure of the switching element, there is a high possibility of switch burnout and a large switching loss. Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The purpose of this invention is to provide a power conversion device and a household appliance having the same, which can reduce switching losses when supplying power to inductive loads.

[0008] Another object of the present invention is to provide a power conversion device and a household appliance having the same, which can reduce the internal pressure of the switching element when supplying power to an inductive load.

[0009] Another object of the present invention is to provide a power conversion device capable of supplying maximum power to an inductive load using resonance, and a household appliance having the same.

[0010] Technical solutions to the problem

[0011] To achieve the above objectives, embodiments of the present invention include a power conversion device and a household appliance having the same, comprising: a first capacitor storing a first voltage; a first switching element switched on to output the first voltage stored in the first capacitor to a first node, which is an inductive load; a second switching element connected at one end to the first switching element and switched on to reduce the voltage of the first node to the first voltage; a third switching element switched on to output a second voltage greater than the first voltage to the first node, which is an inductive load; and a fourth switching element connected at one end to the third switching element and switched on to reduce the voltage of the first node to ground voltage.

[0012] On the one hand, at the first time point, the first switching element is turned on, and the voltage of the first node can rise to the first voltage. At the second time point after the first time point, the third switching element is turned on, and the voltage of the first node can rise from the first voltage to the second voltage. At the third time point after the second time point, the second switching element is turned on, and the voltage of the first node can drop from the second voltage to the first voltage. At the fourth time point after the third time point, the fourth switching element is turned on, and the voltage of the first node can drop from the second voltage to the ground voltage.

[0013] On the one hand, the power conversion device and household appliance having the present invention may further include a resonant capacitor disposed between the other end of the inductive load and ground.

[0014] On the one hand, when the first switching element is turned on during the first time period, the voltage of the first node can rise to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the third switching element is turned on during the second time period, which partially overlaps with the first time period, the voltage of the first node can rise from the first voltage to the second voltage based on the resonance of the inductive load and the resonant capacitor.

[0015] On the one hand, when the second switching element is turned on during the third time period, which is separate from the second time period, the voltage of the first node can drop from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the fourth switching element is turned on during the fourth time period, which partially overlaps with the third time period, the voltage of the first node can drop from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor.

[0016] On one hand, the power conversion device and household appliance having the present invention may further include: a first diode connected between a first switching element and a first node; and a second diode connected between a second switching element and a second node.

[0017] In one aspect, another embodiment of the power conversion device and a household appliance having the same includes: a first switching element and a second switching element connected in series; a first capacitor, one end of which is connected to the first switching element to store a first voltage; an inductive load connected to a first node between the first and second switching elements; and a third switching element and a fourth switching element connected in series; the third and fourth switching elements are connected to the first node, the third switching element is connected to a second voltage source supplying a second voltage, and the voltage of the first node gradually increases as the first and third switching elements are sequentially switched on.

[0018] On the one hand, the voltage of the first node can be increased to the first voltage by turning on the first switching element, and can be increased from the first voltage to the second voltage by turning on the third switching element.

[0019] On the one hand, the voltage of the first node can gradually decrease as the second and fourth switching elements are turned on in sequence.

[0020] On the one hand, the voltage of the first node can be reduced from the second voltage to the first voltage by turning on the second switching element, and can be reduced from the first voltage to the ground voltage by turning on the fourth switching element.

[0021] In another embodiment of the present invention, the power conversion device and the household appliance having therein may further include: an inductive load, one end of which is connected to a first node; and a resonant capacitor disposed between the other end of the inductive load and ground.

[0022] On the one hand, when the first switching element is turned on during the first time period, the voltage of the first node can rise to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the third switching element is turned on during the second time period, which partially overlaps with the first time period, the voltage of the first node can rise from the first voltage to the second voltage based on the resonance of the inductive load and the resonant capacitor.

[0023] On the one hand, when the second switching element is turned on during the third time period, which is separate from the second time period, the voltage of the first node can drop from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the fourth switching element is turned on during the fourth time period, which partially overlaps with the third time period, the voltage of the first node can drop from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor.

[0024] In another embodiment of the present invention, the power conversion device and the household appliance having therein may further include: a first diode connected between a first switching element and a first node; and a second diode connected between a second switching element and a second node.

[0025] Invention Effects

[0026] The power conversion device and household appliance having the present invention, according to embodiments thereof, include: a first capacitor storing a first voltage; a first switching element switched on to output the first voltage stored in the first capacitor to a first node, which is an inductive load; a second switching element connected at one end to the first switching element and switched on to reduce the voltage of the first node to the first voltage; a third switching element switched on to output a second voltage greater than the first voltage to the first node, which is an inductive load; and a fourth switching element connected at one end to the third switching element and switched on to reduce the voltage of the first node to ground voltage. This reduces switching losses when supplying power to an inductive load. Furthermore, it reduces the internal voltage of the switching elements when supplying power to an inductive load.

[0027] On the one hand, at the first time point, turning on the first switching element allows the voltage of the first node to rise to the first voltage. At the second time point after the first time point, turning on the third switching element allows the voltage of the first node to rise from the first voltage to the second voltage. At the third time point after the second time point, turning on the second switching element allows the voltage of the first node to drop from the second voltage to the first voltage. At the fourth time point after the third time point, turning on the fourth switching element allows the voltage of the first node to drop from the second voltage to the ground voltage. This reduces switching losses when supplying power to inductive loads.

[0028] On one hand, the power conversion device and household appliance having the present invention may further include a resonant capacitor disposed between the other end of the inductive load and ground. Thus, maximum power can be supplied to the inductive load using resonance.

[0029] On one hand, when the first switching element is turned on during the first time period, the voltage of the first node can rise to a first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the third switching element is turned on during a second time period that partially overlaps with the first time period, the voltage of the first node can rise from the first voltage to a second voltage based on the resonance of the inductive load and the resonant capacitor. This reduces switching losses when supplying power to the inductive load.

[0030] On the one hand, when the second switching element is turned on during the third time period, which is separate from the second time period, the voltage of the first node can drop from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the fourth switching element is turned on during the fourth time period, which partially overlaps with the third time period, the voltage of the first node can drop from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor. This reduces switching losses when supplying power to the inductive load.

[0031] On one hand, the power conversion device and household appliance having the present invention may further include: a first diode connected between a first switching element and a first node; and a second diode connected between a second switching element and a second node. This allows the formation of a current path depending on the activation of the first or second switching element.

[0032] On one hand, another embodiment of the power conversion device and a household appliance having the same according to the present invention includes: a first switching element and a second switching element connected in series; a first capacitor, one end of which is connected to the first switching element to store a first voltage; an inductive load connected to a first node between the first and second switching elements; and a third switching element and a fourth switching element connected in series; the third and fourth switching elements are connected to the first node, and the third switching element is connected to a second voltage source supplying a second voltage, wherein the voltage of the first node gradually increases as the first and third switching elements are sequentially switched on. This reduces switching losses when supplying power to an inductive load. Furthermore, it reduces the internal voltage of the switching elements when supplying power to an inductive load.

[0033] On the one hand, the voltage of the first node can be increased to a first voltage by turning on the first switching element, and can be increased from the first voltage to a second voltage by turning on the third switching element. This reduces switching losses when supplying power to an inductive load.

[0034] On the one hand, the voltage of the first node can gradually decrease as the second and fourth switching elements are turned on in sequence. This reduces switching losses when supplying power to inductive loads.

[0035] On the one hand, the voltage of the first node can be reduced from the second voltage to the first voltage by turning on the second switching element, and can be reduced from the first voltage to the ground voltage by turning on the fourth switching element.

[0036] On the one hand, another embodiment of the power conversion device and household appliance having the same may further include: an inductive load, one end of which is connected to a first node; and a resonant capacitor disposed between the other end of the inductive load and ground. Thus, maximum power can be supplied to the inductive load using resonance.

[0037] On one hand, when the first switching element is turned on during the first time period, the voltage of the first node can rise to a first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, when the third switching element is turned on during a second time period that partially overlaps with the first time period, the voltage of the first node can rise from the first voltage to a second voltage based on the resonance of the inductive load and the resonant capacitor. This reduces switching losses when supplying power to the inductive load.

[0038] On one hand, during the third time period, which is separate from the second time period, the second switching element is turned on, so that the voltage of the first node can drop from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. On the other hand, during the fourth time period, which partially overlaps with the third time period, the fourth switching element is turned on, so that the voltage of the first node can drop from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor. Thus, switching losses when supplying power to the inductive load can be reduced.

[0039] On one hand, another embodiment of the power conversion device and household appliance having the same may further include: a first diode connected between a first switching element and a first node; and a second diode connected between a second switching element and a second node. This allows the formation of a current path depending on whether the first or second switching element is switched on. Attached Figure Description

[0040] Figure 1 This is an external perspective view of an induction heating cooking device, which is an example of a household appliance according to an embodiment of the present invention.

[0041] Figure 2 yes Figure 1 An example of an internal block diagram of an induction heating cooking device.

[0042] Figure 3 It is shown Figure 1 A diagram illustrating an example of the power supply for an induction heating cooking appliance.

[0043] Figure 4 yes Figure 3 An example of the internal circuit diagram of an induction heating cooking device.

[0044] Figures 5a to 5c The figures illustrate various examples of power conversion devices related to the present invention.

[0045] Figure 6 This is an example of a circuit diagram of a power conversion device according to an embodiment of the present invention.

[0046] Figures 7 to 11 It is used for explanation Figure 6 A reference diagram showing the operation of a power conversion device. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings.

[0048] In the following description, the suffixes "module" and "section" used for constituent elements are merely for ease of writing the specification and are not intended to have any particularly important meaning or function. Therefore, "module" and "section" can be used interchangeably.

[0049] One embodiment of the present invention provides a household appliance equipped with an inductive load, which can be applied to cooking equipment equipped with an induction heating coil, laundry equipment equipped with a motor, air conditioners, refrigerators, mobile robots, cleaning robots, vacuum cleaners, water purifiers, drones, and vehicles, etc. Hereinafter, an example of a household appliance will be described focusing on an induction heating cooking device.

[0050] Figure 1 This is an external perspective view of an induction heating cooking device, which is an example of a household appliance according to an embodiment of the present invention.

[0051] Reference Figure 1 An induction heating cooking device 100 according to an embodiment of the present invention may include a heating plate 110, a first heating part 130, a second heating part 132, a third heating part 134, an input part 125, and a display 180.

[0052] The heating plate 110 serves as the outer casing of the induction heating cooking device 100 and is disposed on each heating element. The heating plate 110 can be made of various materials such as ceramic and tempered glass.

[0053] A cooking container is disposed on the upper part of the heating plate 110. In particular, when the cooking container 195 is disposed on at least one of the heating parts 130, 132, 134 described later, heating is performed by induction heating principle.

[0054] The first heating section 130 has a plurality of induction heating coils and a resonant capacitor (not shown).

[0055] The accompanying drawings illustrate a scenario where the first heating element 130 has a first coil Lr1 and a second coil Lr2.

[0056] The first coil Lr1 can be an induction heating coil used to detect the temperature of the cooking container, and the second induction heating coil Lr2 can be an induction heating coil used to heat the cooking container.

[0057] The accompanying drawings illustrate a scenario where the second induction heating coil Lr2 is disposed around the outer periphery of the first induction heating coil Lr1.

[0058] When the cooking container 195 is placed on the first heating element 130, particularly on the second induction heating coil Lr2, and an alternating current, especially a high-frequency alternating current, flows through the second induction heating coil Lr2, a magnetic field is generated in the second induction heating coil Lr2 due to the resonance between the second induction heating coil Lr2 and the resonant capacitor (not shown). Through the electromagnetic induction effect caused by the magnetic field, eddy currents are induced in the cooking container 195. Joule heat is generated on the resistive component of the cooking container through these eddy currents, thereby heating the cooking container.

[0059] The second heating element 132 includes a third induction heating coil Lr3 and a resonant capacitor (not shown). When the cooking container 195 is placed on the second heating element 132, especially on the third induction heating coil Lr3, and a high-frequency alternating current flows through the third induction heating coil Lr3, the cooking container 195 is heated by eddy current as described above.

[0060] The third heating section 134 includes a fourth induction heating coil Lr4 and a resonant capacitor (not shown). When the cooking container 195 is placed on the third heating section 134, especially on the fourth induction heating coil Lr4, and a high-frequency alternating current flows through the fourth induction heating coil Lr4, the cooking container 195 is heated by eddy current as described above.

[0061] The input unit 125 activates the induction heating cooking device 100 based on the user's operation. For example, through the user's operation, it is possible to determine whether to heat at least one of the first heating unit 130, the second heating unit 132, and the third heating unit 134, or to supply current to which of the first induction heating coil Lr1 and the second induction heating coil Lr2 in the first heating unit 130, or to select the operating time or temperature of each heating unit, etc.

[0062] As shown in the attached figure, each heating section 130, 132, and 134 may also have an input section 125.

[0063] The display 180 shows the overall operating status of the induction heating cooking appliance 100. It displays whether each heating element 130, 132, and 134 is in operation, and the temperature of the cooking container 195 being heated, etc.

[0064] On the one hand, in addition to the induction heating cooking apparatus 100 of the embodiments of the present invention, in radiant heat cooking apparatus, since the heating element under the heating plate 110 is used in the same way as induction heating cooking apparatus 100, there are no sparks and the advantage of high stability. However, since the temperature of the heating element itself will rise according to the radiant heat method, on / off control is required to protect the heating element.

[0065] However, since the induction heating cooking device 100 of the present invention utilizes the principle of high-frequency induction heating, it does not directly heat the heating part, especially the induction heating coil, and can continuously supply high-frequency current, which has the advantages of high energy efficiency and shortened heating time.

[0066] On the one hand, since induction heating is effectively performed when the induction heating cooking device 100 uses a cooking container containing a magnetic material with metallic components, an additional electric heating unit (not shown) can be provided for improvement, i.e., to perform heating even when using a non-magnetic cooking container. The electric heating unit (not shown) can also be configured in at least one of the heating units 130, 132, and 134. Furthermore, the induction heating cooking device 100 may also be provided with a load detection unit (not shown) for detecting the type of cooking container.

[0067] Figure 2 yes Figure 1 An example of an internal block diagram of an induction heating cooking device.

[0068] Referring to the accompanying drawings, the induction heating cooking device 100 may include a first power conversion device 210a, a second power conversion device 210b, an input unit 125, a display 180, and a temperature detection unit 400.

[0069] The first power conversion device 210a and the second power conversion device 210b can supply power to a plurality of induction heating coils within the cooking equipment 100.

[0070] exist Figure 3 The example illustrates how a first power conversion device 210a supplies power to a second induction heating coil Lr2, a third induction heating coil Lr3, and a fourth induction heating coil Lr4, while a second power conversion device 210b supplies power to a first induction heating coil Lr1.

[0071] The input unit 125 may be equipped with buttons, touch screens, etc. that are associated with the operation of the cooking device 100, and signals input into the input unit 125 can be transmitted to the control unit 170.

[0072] The display 180 can display information related to the operating status of the cooking appliance 100. For example, it can display cooking time, remaining time, cooking type information, and the temperature of the cooking container.

[0073] The temperature detection unit 400 can detect the temperature of the cooking container 195. Although there are methods such as IR sensors for temperature detection, this invention provides a solution using a resistive element whose resistance value changes with temperature, considering simplicity and reduced manufacturing costs. The configuration of the resistive element will be explained with reference to FIG5.

[0074] The control unit 170 controls the overall operation of the cooking equipment 100.

[0075] For example, the control unit 170 can control the operation of the first power conversion device 210a, the second power conversion device 210b, the input unit 125, the display 180, and the temperature detection unit 400.

[0076] Specifically, the first power conversion device 210a or the second power conversion device 210b can be controlled to perform cooking based on the temperature signal input to the input unit 25.

[0077] On one hand, the control unit 170 can be controlled to receive temperature information sensed by the temperature detection unit 400 and display the temperature information on the display 180.

[0078] On one hand, the control unit 170 can control the application of a pulse signal to the first coil Lr1 and detect the temperature of the cooking container 195 based on the current flowing in the resistive element corresponding to the pulse signal.

[0079] On the one hand, the control unit 170 can control the second coil Lr2 to continuously operate while heating the cooking container 195, and repeatedly apply pulse signals to the first coil Lr1.

[0080] On the one hand, the control unit 170 can control the amplitude of the pulse signal of the first coil Lr1 or the application time of the pulse signal according to the operating time of the second coil Lr2 or the temperature of the cooking container 195.

[0081] Figure 3 It is shown Figure 1 A diagram illustrating an example of the power supply for an induction heating cooking appliance.

[0082] Reference Figure 3 To explain further, the induction heating cooking device 100 may also include a first power conversion device 210a and a second power conversion device 210b.

[0083] The first power conversion device 210a can supply power to the second induction heating coil Lr2 in the first heating section 130, the third induction heating coil Lr3 in the second heating section 132, and the fourth induction heating coil Lr4 in the third heating section 134. The power here can be high-frequency alternating current.

[0084] The second power conversion device 210b can supply power to the first induction heating coil Lr1 inside the first heating section 130.

[0085] Thus, by supplying power from different power conversion devices to each induction heating coil in the first heating section 130 where multiple induction heating coils are arranged in an overlapping manner, the induction heating cooking device using high-frequency alternating current can be driven effectively and stably without reducing power.

[0086] Figure 4 yes Figure 3 An example of the internal circuit diagram of an induction heating cooking device.

[0087] Referring to the accompanying drawings, a first power conversion device 210a according to an embodiment of the present invention may include a first converter 310, a second converter 312, a first reactor L1, a second reactor L2, a first smoothing capacitor C1, a second smoothing capacitor C2, a first inverter 320, a second inverter 322, a power selection unit 330, and second switching elements S2 to fourth switching elements S4.

[0088] The second power conversion device 210b may include a third converter 314, a third reactor L3, a third smoothing capacitor C3, a third inverter 324, and a first switching element S1.

[0089] The first converter 310 and the second converter 312 receive commercial AC power 305, convert it into DC power, and output it. For example, the first converter 310 and the second converter 312 may have diode elements, so that the power rectified in the diode elements is output as DC power.

[0090] On the one hand, the first converter 310 and the second converter 312 may also have diode elements and switching elements, and the output is a DC power supply converted according to the switching action of the switching elements and the rectification characteristics of the diode elements.

[0091] The following description focuses on the case where the first converter 310 and the second converter 312 are composed of diode elements rather than switching elements.

[0092] On one hand, the commercial AC power supply 305 can be a single-phase AC power supply or a three-phase AC power supply. When the commercial AC power supply 305 is a single-phase AC current, the first converter 310 and the second converter 312 can be in a bridge configuration and include four diode elements. When the commercial AC power supply 305 is a three-phase AC power supply, the first converter 310 and the second converter 312 can include six diode elements.

[0093] On one hand, the third converter 314, like the first converter 310 and the second converter 312, receives commercial AC power and converts it into DC power output. At this time, to prevent power degradation, the third converter 314 can receive an additional commercial AC power supply 307.

[0094] The first reactor L1 and the second reactor L2 are respectively connected to one end of the first converter 310 and the second converter 312. By accumulating the energy of the AC component, they can remove harmonic current components or noise components.

[0095] The third reactor L3 is connected to one end of the third converter 314. By accumulating the energy of the AC component, it plays the role of removing harmonic current components or noise components.

[0096] The first smoothing capacitor C1 and the second smoothing capacitor C2 are respectively connected to the output terminals of the first converter 310 and the second converter 312. In the accompanying drawings, reactors L1 and L2 are respectively disposed between the capacitors and the converters 310 and 312.

[0097] The first smoothing capacitor C1 and the second smoothing capacitor C2 transform the rectified power supply output from the first converter 310 and the second converter 312 into a smooth DC power supply. Hereinafter, the output terminals of the first converter 310 and the second converter 312 will be referred to as the first DC terminal and the second DC terminal, respectively. The smoothed DC voltages of the first DC terminal and the second DC terminal are applied to the first inverter 320 and the second inverter 322, respectively.

[0098] The third capacitor C3 is connected to the output terminal of the third converter 314, making the rectified power supply output from the third converter 314 a smooth DC power supply. The output terminal of the third converter 314 is called the third DC terminal.

[0099] The first inverter 320, the second inverter 322, and the third inverter 324 each have a plurality of switching elements, and through the on / off operation of the switching elements, they convert smooth DC power supply into AC power supply of a specified frequency.

[0100] The first inverter 320 has an upper arm switching element Sa and a lower arm switching element S′a connected in series. A diode is connected in reverse parallel to each switching element Sa and S′a. Additionally, a snubber capacitor is connected in parallel to each switching element Sa and S′a.

[0101] The switching elements Sa and S′a within the first inverter 320 perform on / off operations based on a first switching control signal from the control unit (not shown). At this time, the switching elements Sa and S′a can also operate in a complementary manner.

[0102] Similar to the first inverter 320, the second inverter 322 has an upper arm switching element Sb and a lower arm switching element S′b connected in series. A diode is connected in reverse parallel to each switching element Sb and S′b. Additionally, a buffer capacitor is connected in parallel to each switching element Sb and S′b.

[0103] The switching elements Sb and S′b in the second inverter 320 perform on / off operations based on the second switching control signal from the control unit (not shown).

[0104] The first inverter 320 and the second inverter 322 can operate independently. That is, they can generate and output a first high-frequency AC power supply and a second high-frequency AC power supply, respectively.

[0105] Similar to the first inverter 320, the third inverter 324 has an upper arm switching element Sc and a lower arm switching element S′c connected in series with each other. Additionally, diodes and buffer capacitors are connected.

[0106] A fourth resonant capacitor Cr4 for resonance can be connected to the second induction heating coil Lr2. Based on the aforementioned induction heating principle, induction heating can be achieved by supplying a high-frequency AC power supply to the second induction heating coil Lr2. At this time, the switching element S4, which determines the operation of the second induction heating coil Lr2, can be connected to the second induction heating coil Lr2.

[0107] On one hand, the second induction heating coil Lr2 receives the first AC power output from the first inverter 320.

[0108] The third induction heating coil Lr3 and the fourth induction heating coil Lr4 are connected in parallel to each other and form a pair. On one hand, a second resonant capacitor Cr2 and a third resonant capacitor Cr3 can be connected to the third induction heating coil Lr3 and the fourth induction heating coil Lr4 respectively for resonance. According to the above-described induction heating principle, induction heating can be achieved by supplying high-frequency AC power to each induction heating coil Lr2 and Lr3. At this time, the switching elements S2 and S3, which determine the operation of each induction heating coil Lr2 and Lr3, can be connected to the third induction heating coil Lr3 and the fourth induction heating coil Lr4 respectively.

[0109] On one hand, the third induction heating coil Lr3 and the fourth induction heating coil Lr4 receive a first AC power supply from the first inverter 320 or a second AC power supply from the second inverter 322. For this purpose, the power selection unit 330 performs a switching operation.

[0110] When both the third induction heating coil Lr3 and the second induction heating coil Lr2 are in operation, the power selection unit 330 controls the power supply to select either the first AC power supply from the first inverter 320 or the second AC power supply from the second inverter 322 and supply it to the third induction heating coil Lr3, and select the other to supply it to the fourth induction heating coil Lr4.

[0111] For example, it can be controlled to supply the second AC power to the third induction heating coil Lr3 and the first AC power to the fourth induction heating coil Lr4.

[0112] Therefore, when at least three of the multiple induction heating coils that need to be connected in parallel with the same inverter are turned on, the AC power applied to each induction heating coil can be separated. That is, corresponding AC power can be received from different inverters. Thus, the same AC power is not received from the same inverter, thereby preventing power loss and allowing for stable and separate reception of AC power.

[0113] Therefore, the power selection unit 330 may have a relay element. The accompanying drawings illustrate a power selection unit 330 with a relay element R.

[0114] The relay element R can be configured between the inverters 320 and 322 and the fourth induction heating coil Lr4, and perform relay operation to connect the fourth induction heating coil Lr4 to either the first inverter 320 or the second inverter 322.

[0115] On the one hand, the control of the relay operation of the relay element R can be executed according to the control signal of the control unit (not shown).

[0116] A first resonant capacitor Cr1 for resonance can be connected to the first induction heating coil Lr1. According to the aforementioned induction heating principle, induction heating can be achieved by supplying a high-frequency AC power supply to the first induction heating coil Lr1. At this time, the switching element S1, which determines the operation of the first induction heating coil Lr1, can be connected to the first induction heating coil Lr1.

[0117] On the one hand, a third AC power supply from the third inverter 324 is supplied to the first induction heating coil Lr1.

[0118] On one hand, the control unit (not shown) can control the operation of the switching elements Sa and S′a in the first inverter 320, the switching elements Sb and S′b in the second inverter 322, the switching elements Sc and S′c in the third inverter 324, the relay element R in the power selection unit 330, and the operation of the first to fourth switching elements S1 for the operation of each induction heating coil.

[0119] In particular, for the control of the first inverter 320, the second inverter 322, and the third inverter 324, a pulse width modulation (PWM) switching control signal can be output. When the switching elements in the first inverter 320, the second inverter 322, and the third inverter 324 are insulated-gate bipolar transistors (IGBTs), a pulse width modulation (PWM) gate drive control signal can be output.

[0120] On the other hand, the control unit (not shown) can also receive corresponding values ​​from the temperature sensing unit (not shown) that senses the temperature near each induction heating coil and the input current detection unit (not shown) that detects the input current from the commercial AC power supply, and stop the operation of the induction heating cooking device 100 as a whole in case of an abnormality.

[0121] Figures 5a to 5c The figures illustrate various examples of power conversion devices related to the present invention.

[0122] first, Figure 5a This is an example of a circuit diagram for a power conversion device 210xa with a single-ended resonant inverter.

[0123] Referring to the attached diagram, the power conversion device 210xa utilizes the voltage rectified in the rectifier RET and supplies power to the inductive load Lr and the resistive element Rcq through the coil coil, capacitor Cm, resonant capacitor Cr, and a switching element Q.

[0124] Figure 5b This is an example of a circuit diagram for a power conversion device 210xb with a half-bridge resonant inverter.

[0125] Referring to the attached diagram, the power conversion device 210xb uses the voltage rectified in the rectifier section RET to supply power to the inductive load Lr and the resistive element Rcq through the coil coil, capacitor Cm, a pair of resonant capacitors Cr1 and Cr2, and a pair of switching elements Q1 and Q2 in half-bridge configuration.

[0126] Figure 5c This is an example of a circuit diagram for a power conversion device 210xc with a full-bridge resonant inverter.

[0127] Referring to the attached diagram, the power conversion device 210xc uses the DC terminal voltage Vdc and two pairs of switching elements Q1, Q2, Q3, and Q4 in full-bridge configuration to supply power to the inductive load Lr and the resonant capacitor Cr.

[0128] However, when using power conversion devices 210xa with single-ended resonant inverters and 210xb with half-bridge resonant inverters, the operating frequency is low, resulting in the disadvantage of large sizes for resonant capacitors and resonant inductors. Furthermore, due to the high internal voltage of the switching elements, there is a high probability of switch burnout and significant switching losses.

[0129] On the one hand, when using the power conversion device 210xc with a full-bridge resonant inverter, there is a high possibility of switch burnout and large switching losses due to the high internal voltage of the switching elements.

[0130] Therefore, the present invention provides a solution for reducing switching losses while reducing the internal pressure of the switching element.

[0131] Figure 6 This is an example of a circuit diagram of a power conversion device according to an embodiment of the present invention. Figures 7 to 11 It is used for explanation Figure 6 A reference diagram showing the operation of a power conversion device.

[0132] First, refer to Figure 6 The power conversion device 210 of an embodiment of the present invention includes: a first capacitor Cs storing a first voltage 0.5Vs; a first switching element SW1, which, when turned on, outputs the first voltage 0.5Vs stored in the first capacitor Cs to a first node nda, which is one end of an inductive load Lr; a second switching element SW2, one end of which is connected to the first switching element SW1, which, when turned on, reduces the voltage of the first node nda to the first voltage 0.5Vs; a third switching element SW3, which, when turned on, outputs a second voltage Vs, which is greater than the first voltage 0.5Vs, to the first node nda, which is one end of an inductive load Lr; and a fourth switching element SW4, one end of which is connected to the third switching element SW3, which, when turned on, reduces the voltage of the first node nda to the ground voltage GND.

[0133] Therefore, switching losses when supplying power to the inductive load Lr can be reduced. Additionally, the internal voltage of the switching elements when supplying power to the inductive load Lr can be reduced.

[0134] In addition, it can realize high-speed switching of the first switching element to the fourth switching element SW1 to SW4.

[0135] For example, Figure 5c The switching frequency of the switching elements Q1 to Q4 in the power conversion device 210xc can be approximately 30kHz, however, Figure 6 The switching frequency of the first to fourth switching elements SW1 to SW4 can be increased to approximately 200 kHz.

[0136] On the one hand, by means of the resonance between the inductive load Lr and the resonant capacitor Cr, the maximum resonant voltage compared to the input voltage can be supplied to the inductive load Lr.

[0137] On one hand, the power conversion device 210 of an embodiment of the present invention may further include a resonant capacitor Cr disposed between the other end ndb of the inductive load Lr and ground GND. Therefore, maximum power can be supplied to the inductive load Lr using resonance.

[0138] On one hand, the power conversion device 210 of this embodiment may further include: a first diode D1 connected between the first switching element SW1 and the first node nda; and a second diode D2 connected between the second switching element SW2 and the second node ndc. Therefore, a current path can be formed depending on whether the first switching element SW1 or the second switching element SW2 is turned on.

[0139] As shown in the attached diagram, the second node ndc can be connected to the anode of the first diode D1, the first node nda can be connected to the cathode of the first diode D1, the second node ndc can be connected to the cathode of the second diode D2, and the first node nda can be connected to the anode of the second diode D2.

[0140] Therefore, by turning on the first switching element SW1, the first diode D1 is turned on, and the current flows from the capacitor Cs through the first switching element SW1 and the first diode D1, but does not flow towards the second diode D2.

[0141] On the one hand, by turning on the second switching element SW2, the second diode D2 is turned on, and the current flows through the second switching element SW2, the second diode D2, and the capacitor Cs, instead of flowing towards the first diode D1.

[0142] On one hand, in another embodiment of the present invention, the power conversion device 210 includes: a first switching element SW1 and a second switching element SW2 connected in series; a first capacitor Cs, one end of which is connected to the first switching element SW1, storing a first voltage of 0.5Vs; an inductive load Lr connected to a first node nda between the first and second switching elements SW1 and SW2; and a third switching element SW3 and a fourth switching element SW4 connected in series. A first node nda is connected between the third and fourth switching elements SW4, and the third switching element SW3 is connected to a second voltage source supplying the second voltage Vs. The voltage at the first node nda gradually increases as the first switching element SW1 and the third switching element SW3 are sequentially switched on. Therefore, switching losses when supplying power to the inductive load Lr can be reduced. Furthermore, the internal voltage of the switching elements when supplying power to the inductive load Lr can be reduced.

[0143] On the one hand, the voltage of the first node nda can rise to a first voltage of 0.5Vs when the first switching element SW1 is turned on, and can rise from the first voltage of 0.5Vs to a second voltage Vs when the third switching element SW3 is turned on. Therefore, the switching losses when supplying power to the inductive load Lr can be reduced.

[0144] On the one hand, the voltage at the first node nda can gradually decrease as the second switching element SW2 and the fourth switching element SW4 are turned on in sequence. Therefore, switching losses when supplying power to the inductive load Lr can be reduced.

[0145] On the one hand, the voltage of the first node nda can drop from the second voltage Vs to the first voltage 0.5Vs as the second switching element SW2 is turned on, and can drop from the first voltage 0.5Vs to the ground voltage GND as the fourth switching element SW4 is turned on.

[0146] Figure 7 It is shown Figure 6 A timing diagram showing the turn-on time of each switching element SW1 to SW4 in the power conversion device 210 and the voltage change of the first node nda that occurs thereafter.

[0147] Referring to the attached diagram, on one hand, at the first time point Ta1, the first switching element SW1 is turned on. At time point Tr1, the voltage of the first node nda can rise from the ground voltage to the first voltage 0.5Vs. At the second time point Ta3, following the first time point Ta1, the third switching element SW3 is turned on. At time point Tr2, the voltage of the first node nda can rise from the first voltage 0.5Vs to the second voltage Vs. At the third time point Ta2, following the second time point Ta3, the second switching element SW2 is turned on. At time point Tf1, the voltage of the first node nda can drop from the second voltage Vs to the first voltage 0.5Vs. At the fourth time point Ta4, following the third time point Ta2, the fourth switching element SW4 is turned on. At time point Tf2, the voltage of the first node nda can drop from the first voltage 0.5Vs to the ground voltage GND. This reduces switching losses when supplying power to the inductive load Lr.

[0148] As shown in the attached figure, when the voltage at the first node nda rises from the ground voltage to the second voltage Vs, it gradually increases after passing through the first voltage 0.5Vs. Therefore, when the first switching element SW1 or the third switching element SW3 is turned on, the instantaneous current level becomes lower, thereby reducing switching losses.

[0149] Similarly, when the voltage at the first node nda drops from the second voltage Vs to the ground voltage, it gradually decreases after passing through the first voltage 0.5Vs. Therefore, when the second switching element SW2 or the fourth switching element SW4 is turned on, the instantaneous current level becomes lower, thereby reducing switching losses.

[0150] Figure 8a It shows having Figure 5c The diagram shows the voltage Vq1 across the switching element Q1 and the current Iq1 flowing through it in the power conversion device 210xc of the full-bridge resonant inverter.

[0151] Referring to the attached figure, the switching element Q1 in the power conversion device 210xc is turned on to supply the second voltage Vs to the inductive load Lr. Therefore, as shown in the figure, the voltage waveform rises sharply from the ground voltage to the second voltage Vs.

[0152] Furthermore, the current Iq1 flowing in the switching element Q1 rises partially when the voltage drops due to the time delay caused by the inductive load Lr, thereby creating a region Ara that overlaps between the voltage Vq1 and the current Iq1.

[0153] This overlapping region Ara represents the power consumed by the switching element Q1, which manifests as switching losses.

[0154] Figure 8b This illustrates an embodiment of the present invention. Figure 6 The diagram shows the voltage Vsw1 across the first switching element SW1 and the current Isw1 flowing through it within the power conversion device 210.

[0155] Referring to the attached figure, the first switching element SW1 in the power conversion device 210 is turned on to supply a first voltage of 0.5Vs to the inductive load Lr. Therefore, as shown in the figure, the voltage waveform rises sharply from the ground voltage to the first voltage of 0.5Vs.

[0156] Furthermore, the current Isw1 flowing through the first switching element SW1 rises partially as the voltage drops due to the time delay caused by the inductive load Lr, thereby creating a region Arb that overlaps between the voltage Vsw1 and the current Isw1.

[0157] This overlapping region Arb represents the power consumed by the first switching element SW1, and manifests as a switching loss.

[0158] However, with Figure 8a Compared to the overlapping region Ara, Figure 8b The overlap region Arb is smaller, thus reducing switching losses.

[0159] on the one hand, Figure 8bThe internal voltage of the first switching element SW1 is approximately 0.5Vs, and... Figure 8a Compared to the internal voltage Vs of the switching element Q1, it is reduced by approximately half. Therefore... Figure 8b The internal pressure of the first switching element SW1 drops.

[0160] Figure 9a It shows the basis Figure 5c A diagram showing the current path formed by the switching elements Q1 and Q3 in the power conversion device 210xc with a full-bridge resonant inverter.

[0161] Referring to the attached diagram, firstly, the first switching element Q1 and the fourth switching element Q4 are switched on, thereby forming a current path like Ipathxa. The voltage at one end nd of the inductive load Lr rises from the ground voltage to the Vs voltage and is maintained at approximately the Vs voltage.

[0162] Then, the second switching element Q2 and the third switching element Q3 are turned on, thereby forming a current path like Ipathxb, and the voltage at one end nd of the inductive load Lr drops from the Vs voltage to the ground voltage.

[0163] On the one hand, according to Figure 9a In such a way, such as Figure 8a The explanation states that there are drawbacks such as increased switching losses and increased internal pressure of the switching element.

[0164] Figure 9b This is based on the embodiments of the present invention. Figure 6 A diagram showing the current path formed by the switching elements SW1 to SW4 in the power conversion device 210.

[0165] Referring to the attached diagram, at the first time point Ta1, the first switching element SW1 is turned on. This forms a current path, as shown in Ipath1, flowing through the capacitor Cs, the first switching element SW1, the first diode D1, the inductive load Lr, and the resonant capacitor Cr.

[0166] Based on this resonant current path, the voltage at the first node nda rises from the ground voltage to a first voltage of 0.5Vs.

[0167] Then, at the second time point Ta3, following the first time point Ta1, the third switching element SW3 is turned on. This forms a current path, Ipath2, flowing through the second voltage source, the third switching element SW3, the inductive load Lr, and the resonant capacitor Cr.

[0168] Based on this resonant current path, the voltage of the first node nda rises from the first voltage 0.5Vs to the second voltage Vs.

[0169] Then, at the third time point Ta2, following the second time point Ta3, the second switching element SW2 is turned on. This forms a current path, Ipath3, flowing through capacitor Cs, the second switching element SW2, the second diode D2, the inductive load Lr, and the resonant capacitor Cr.

[0170] Based on this resonant current path, the voltage of the first node nda drops from the second voltage Vs to the first voltage 0.5Vs.

[0171] Then, at the fourth time point Ta4, following the third time point Ta2, the fourth switching element SW4 is turned on. This creates a current path, such as Ipath4, flowing through ground, the fourth switching element SW4, the inductive load Lr, and the resonant capacitor Cr.

[0172] Based on this resonant current path, the voltage of the first node nda drops from the first voltage of 0.5Vs to the ground voltage.

[0173] Figure 10a (a) and Figure 9a The current path of Ipathxa is associated with the current waveform flowing through the first switching element Q1. Figure 10a (b) and Figure 9a The current path of Ipathxb is associated with the current waveform flowing through the third switching element Q3.

[0174] Figure 10b (a) and Figure 9b The current path of Ipath1 is associated with an example of the current waveform flowing through the first switching element SW1. Figure 10b (b) and Figure 9b The current path of Ipath2 is illustrated in relation to the current waveform flowing through the third switching element SW3. Figure 10b (c) and Figure 9b The current path of Ipath3 is associated with an example of the current waveform flowing through the second switching element SW2. Figure 10b (d) and Figure 9b The current path of Ipath4 is associated with an example of the current waveform flowing through the fourth switching element SW4.

[0175] Figure 10c Example (a) provides Figure 9a The voltage waveform VQ1 of the first switching element Q1, Figure 10c Example (b) provides Figure 9b The voltage waveform Vsw1 of the first switching element SW1, Figure 10c Example (c) provides Figure 9b The voltage waveform Vsw3 of the third switching element SW3.

[0176] Figure 10c The maximum level of the voltage waveform VQ1 of the first switching element Q1 in (a) is LV1, which is higher than that of the first switching element Q1 in (a). Figure 10c The voltage waveform Vsw1 of the first switching element SW1 in (b) is approximately twice as large as the maximum level of Lv2.

[0177] Therefore, the internal pressure of the first switching element SW1 in the power conversion device 210 of the present invention is reduced to approximately half that of the internal pressure of the first switching element Q1 in the power conversion device 210Xc with a full-bridge inverter.

[0178] On the one hand, refer to Figure 10c The voltage waveform Vsw3 of the third switching element SW3 in (c) gradually increases from Lv2 to Lv1, or gradually decreases from Lv1 to Lv2, thus reducing the internal voltage compared to the first switching element Q1 in the power conversion device 210Xc with a full-bridge inverter.

[0179] Figure 10d Example (a) provides Figure 9a The switching loss waveform LSx of the first switching element Q1, Figure 10d Example (b) provides Figure 9b The switching loss waveform LSs of the first switching element SW1.

[0180] Figure 10d The switching loss waveforms LSx and LSs in (a) can represent the power consumption waveforms of the switching element.

[0181] Referring to the attached diagram, it can be confirmed that, compared to Figure 10d The switching loss waveform LSx in (a) Figure 10d The switching loss waveform LSs in (b) has a lower level.

[0182] That is, the power conversion device 210 according to an embodiment of the present invention can reduce switching losses when supplying power to an inductive load Lr.

[0183] Figure 11 (a) shows the current waveform IL flowing through the inductive load Lr. Figure 11 (b) shows the voltage Vc across the resonant capacitor Cr. Figure 11 (c) is a diagram illustrating the switching sequence (SWW) of the switching elements SW1 to SW4 in the power conversion device 210 according to Figure 9.

[0184] A predetermined phase difference is generated between the current waveform IL flowing through the inductive load Lr and the voltage Vc across the resonant capacitor Cr.

[0185] On the one hand, according to Figure 11In the switching timing (SWW) of (c), during the first time period t1, the first switching element SW1 is turned on, and the voltage of the first node nda rises to a first voltage of 0.5Vs based on the resonance of the inductive load Lr and the resonant capacitor Cr. During the second time period t2, which partially overlaps with the first time period t1, the third switching element SW3 is turned on, and the voltage of the first node nda rises from the first voltage of 0.5Vs to a second voltage Vs based on the resonance of the inductive load Lr and the resonant capacitor Cr. This reduces switching losses when supplying power to the inductive load Lr.

[0186] At this time, the overlapping time period can be approximately 0.1 times the on-time period of the first switching element SW1 or the third switching element SW3.

[0187] On one hand, during the third time period t3, which is separated from the second time period t2, the second switching element SW2 is turned on, and the voltage of the first node nda drops from the second voltage Vs to the first voltage 0.5Vs based on the resonance of the inductive load Lr and the resonant capacitor Cr. During the fourth time period t4, which partially overlaps with the third time period t3, the fourth switching element SW4 is turned on, and the voltage of the first node nda drops from the first voltage 0.5Vs to the ground voltage GND based on the resonance of the inductive load Lr and the resonant capacitor Cr. This reduces switching losses when supplying power to the inductive load Lr.

[0188] At this time, the overlapping time period can be approximately 0.1 times the on-time period of the second switching element SW2 or the fourth switching element SW4.

[0189] On the one hand, the power conversion device 210 according to an embodiment of the present invention can supply maximum energy to both ends of the inductive load Lr by controlling the frequency value, even when the input voltage (e.g., Vs) is low.

[0190] That is, by controlling the frequency to increase as the input voltage decreases, the maximum energy can be supplied to both ends of the inductive load Lr.

[0191] On the one hand, the power conversion device 210 according to an embodiment of the present invention can minimize the noise filter design by minimizing the conduction noise.

[0192] Furthermore, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Various modifications can be made by those skilled in the art without departing from the spirit of the invention as claimed in the claims, and these modifications should not be understood separately from the technical concept or prospect of the present invention.

[0193] Industrial applicability

[0194] This invention can be applied to power conversion devices and household appliances having the same, and more specifically, to power conversion devices and household appliances having the same that can reduce switching losses when supplying power to inductive loads.

Claims

1. A power conversion device, characterized in that, include: The first capacitor stores the first voltage; The first switching element is turned on to output the first voltage stored in the first capacitor to the first node, which is one end of the inductive load; The second switching element is connected at one end to the first switching element and is turned on to reduce the voltage of the first node to the first voltage. A third switching element is turned on to output a second voltage greater than the first voltage to the first node, which is one end of the inductive load; A fourth switching element is connected to one end of the third switching element and is turned on to reduce the voltage of the first node to ground voltage; as well as A resonant capacitor is disposed between the other end of the inductive load and ground. When the first switching element is turned on during the first time period, the voltage of the first node rises to the first voltage based on the resonance of the inductive load and the resonant capacitor. During a second time period that partially overlaps with the first time period, the third switching element is turned on, and the voltage of the first node rises from the first voltage to the second voltage based on the resonance of the inductive load and the resonant capacitor.

2. The power conversion device according to claim 1, characterized in that, At the first time point, the first switching element is turned on, and the voltage of the first node rises to the first voltage. At a second time point after the first time point, the third switching element is turned on, and the voltage of the first node rises from the first voltage to the second voltage. At a third time point after the second time point, the second switching element is turned on, and the voltage at the first node drops from the second voltage to the first voltage. At a fourth time point following the third time point, the fourth switching element is turned on, and the voltage of the first node drops from the second voltage to the ground voltage.

3. The power conversion device according to claim 1, characterized in that, During a third time period separate from the second time period, the second switching element is turned on, and the voltage of the first node drops from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. During a fourth time period that partially overlaps with the third time period, the fourth switching element is turned on, and the voltage of the first node drops from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor.

4. The power conversion device according to claim 1, characterized in that, Also includes: A first diode connected between the first switching element and the first node; as well as A second diode connected between the second switching element and the second node.

5. A power conversion device, characterized in that, include: The first switching element and the second switching element are connected in series with each other; The first capacitor has one end connected to the first switching element and stores the first voltage. An inductive load is connected to a first node between the first switching element and the second switching element; The third and fourth switching elements are connected in series with each other; as well as A resonant capacitor is disposed between the other end of the inductive load and ground. The third and fourth switching elements are connected to the first node. The third switching element is connected to the second voltage source that supplies the second voltage. The voltage at the first node gradually increases as the first switching element and the third switching element are turned on in sequence. When the first switching element is turned on during the first time period, the voltage of the first node rises to the first voltage based on the resonance of the inductive load and the resonant capacitor. During a second time period that partially overlaps with the first time period, the third switching element is turned on, and the voltage of the first node rises from the first voltage to the second voltage based on the resonance of the inductive load and the resonant capacitor.

6. The power conversion device according to claim 5, characterized in that, The voltage of the first node rises to the first voltage by turning on the first switching element, and rises from the first voltage to the second voltage by turning on the third switching element.

7. The power conversion device according to claim 5, characterized in that, The voltage of the first node gradually decreases as the second and fourth switching elements are turned on in sequence.

8. The power conversion device according to claim 7, characterized in that, The voltage of the first node drops from the second voltage to the first voltage by turning on the second switching element, and drops from the first voltage to the ground voltage by turning on the fourth switching element.

9. The power conversion device according to claim 5 and the household appliance having the same, characterized in that, During a third time period separate from the second time period, the second switching element is turned on, and the voltage of the first node drops from the second voltage to the first voltage based on the resonance of the inductive load and the resonant capacitor. During a fourth time period that partially overlaps with the third time period, the fourth switching element is turned on, and the voltage of the first node drops from the first voltage to the ground voltage based on the resonance of the inductive load and the resonant capacitor.

10. The power conversion device according to claim 5, characterized in that, Also includes: A first diode connected between the first switching element and the first node; as well as A second diode connected between the second switching element and the second node.

11. A household appliance comprising the power conversion device according to any one of claims 1 to 10.

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