WO2018120817A1 - Frequency converter and microwave oven - Google Patents

Abstract

A frequency converter (10) and a microwave oven (100). The frequency converter (10) comprises an inversion switch unit (11), a boost transformer (12), and a voltage-multiplying rectification unit (13). The inversion switch unit (11) comprises a switching transistor (111), a resonant capacitor (112), and a resonant inductor (113). The resonant capacitor (112) is connected between the switching transistor (111) and the resonant inductor (113); the boost transformer (12) comprises a primary winding (121) and a secondary winding (122); one end of the primary winding (121) is connected to one end of the resonant capacitor (112) by means of the resonant inductor (113), and the other end of the primary winding (121) is connected to the other end of the resonant capacitor (112) and the switching transistor (111); and the secondary winding (122) is connected to the voltage-multiplying rectification unit (13).

Description

Frequency converter and microwave oven

Priority information

This application claims the priority of the patent application number 201621470707.X submitted to the State Intellectual Property Office of China on December 29, 2016, and the patent application number is 201611246722.0 and submitted to the State Intellectual Property Office of China on December 29, 2016. And rights, and the full text is incorporated herein by reference.

Technical field

The invention relates to the field of household appliances, and in particular to a frequency converter and a microwave oven.

Background technique

In the related art, the step-up transformer of the inverter of the microwave oven needs to reduce the magnetic coupling between the primary and secondary windings of the step-up transformer in order to obtain the required leakage inductance for resonance, which may result in energy transmission of the transformer. The efficiency is reduced, and the overall temperature rise of the inverter is too high, which will reduce the reliability of the inverter operation and affect the service life of the inverter.

Summary of the invention

The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the present invention needs to provide a frequency converter and a microwave oven.

The frequency converter of the embodiment of the present invention is used for a microwave oven, and the frequency converter includes an inverter switch unit, a step-up transformer, and a voltage doubler rectifying unit, and the inverter switch unit includes a switch tube, a resonant capacitor, and a resonant inductor, and the resonant capacitor is connected. Between the switching tube and the resonant inductor, the step-up transformer includes a primary winding and a secondary winding, and one end of the primary winding is connected to one end of the resonant capacitor through the resonant inductor, the primary winding The other end of the line is connected to the other end of the resonant capacitor and the switch tube, and the secondary winding is connected to the voltage doubler rectifying unit.

In the frequency converter of the embodiment of the invention, the inverter switching unit is added, so that the resonant inductor can be separately provided from the step-up transformer, so that the resonant inductor does not affect the magnetic coupling between the primary winding and the secondary winding, and thus can be strengthened The magnetic coupling capability of the primary winding and the secondary winding improves the energy transmission efficiency of the step-up transformer, thereby improving the overall efficiency of the frequency converter and ensuring the reliability of the operation of the frequency converter.

In one embodiment, the step-up transformer includes a magnetic core assembly, a first bobbin and a second bobbin, the first bobbin and the second bobbin are hollow, and the primary winding is wound around the first The secondary winding Wrapped around the second bobbin, the second bobbin and the secondary winding are disposed in the first bobbin, the core assembly includes a first core and a second core, the A magnetic core includes a first post, and the second magnetic core includes a second post, the first post and the second post being disposed in the second bobbin and spaced apart.

In one embodiment, the first bobbin includes two annular first retaining rings and a first frame connecting the two first retaining rings, and the primary winding is wound around the first frame. The second bobbin includes two annular second retaining rings and a second frame connecting the two second retaining rings, and the secondary winding is wound around the second frame.

In one embodiment, the first frame body and the second frame body each have a hollow cylindrical shape, the first frame and the second frame are concentrically disposed, the length of the first frame and the The length of the second skeleton is equal.

In one embodiment, the edge of the first retaining ring is provided with a first notch, the edge of the second retaining ring is provided with a second notch, and the primary winding passes through the first notch, and the second The grade winding passes through the second gap.

In one embodiment, the first core is U-shaped and the second core is U-shaped.

In one embodiment, the resonant inductor includes a toroidal magnetic core and a winding that is evenly wound around the magnetic core, the winding being inserted into a circuit of the frequency converter.

In one embodiment, the frequency converter includes a rectifying unit and an inverter control unit, the rectifying unit is connected in parallel with the inverter switching unit, and the rectifying unit is configured to convert alternating current into direct current, the inverter control unit It is connected in parallel with the inverter switch unit and is used for controlling the on and off of the switch tube.

In one embodiment, the rectifying unit is connected to an alternating current power source, and the rectifying unit is configured to convert an alternating current of the alternating current power source into a direct current power.

In one embodiment, the rectifying unit comprises a rectifier bridge.

In one embodiment, the frequency converter includes a filtering unit that connects the rectifying unit and the inverter control unit.

In one embodiment, the filtering unit includes an inductor and a capacitor, the inductor being in parallel with the capacitor.

A microwave oven according to an embodiment of the present invention includes a magnetron and a frequency converter according to any of the above embodiments, and the voltage doubler rectifying unit is connected to the magnetron.

In the microwave oven of the embodiment of the present invention, the inverter switch unit is added, so that the resonant inductor can be disposed separately from the step-up transformer, so that the resonant inductor does not affect the magnetic coupling between the primary winding and the secondary winding, and thus the primary can be strengthened. The magnetic coupling capability of the winding and the secondary winding improves the energy transmission efficiency of the step-up transformer, thereby improving the overall efficiency of the frequency converter and ensuring the reliability of the operation of the frequency converter.

Additional aspects and advantages of the embodiments of the invention will be set forth in part in the description.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a circuit diagram of a microwave oven according to an embodiment of the present invention.

2 is a schematic perspective view of a step-up transformer of an inverter of a microwave oven according to an embodiment of the present invention.

3 is an exploded perspective view of a step-up transformer of an inverter of a microwave oven according to an embodiment of the present invention.

4 is a perspective view showing a first skeleton and a second skeleton of a step-up transformer of an inverter of a microwave oven according to an embodiment of the present invention.

Fig. 5 is a plan view schematically showing a resonance inductance of a frequency converter of a microwave oven according to an embodiment of the present invention.

The main component symbol description:

Microwave oven 100;

Inverter 10, inverter switch unit 11, switch tube 111, resonant capacitor 112, resonant inductor 113, magnetic core 114, winding 115, step-up transformer 12, primary winding 121, secondary winding 122, core assembly 123 a first magnetic core 1231, a second magnetic core 1232, a first pillar 1233, a second pillar 1234, a first skeleton 124, a first retaining ring 1241, a first frame 1242, a first notch 1243, a second skeleton 125, a second retaining ring 1251, a second frame 1252, a second notch 1253, a voltage doubler rectifying unit 13, a rectifying unit 14, an inverter control unit 15, a filtering unit 16, an inductor 161, a capacitor 162, an AC power source 17;

Magnetron 20.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Orientations of "post", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. The positional relationship is based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of the description of the present invention and the simplified description, and is not intended to indicate or imply that the device or component referred to has a specific orientation, and is constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the invention. Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include one or more of the described features either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and specifically defined otherwise.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or connected in one piece. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, which can be the internal communication of two elements or the interaction of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

Referring to FIG. 1 to FIG. 5 together, the frequency converter 10 according to the embodiment of the present invention is used in a microwave oven 100. The frequency converter 10 includes an inverter switching unit 11, a step-up transformer 12, and a voltage doubler rectifying unit 13. The inverter switch unit 11 includes a switch tube 111, a resonance capacitor 112, and a resonance inductor 113. The resonant capacitor 112 is connected between the switching transistor 111 and the resonant inductor 113. The step-up transformer 12 includes a primary winding 121 and a secondary winding 122. One end of the primary winding 121 is connected to one end of the resonant capacitor 112 through a resonant inductor 113, and the other end of the primary winding 121 is connected to the other end of the resonant capacitor 112 and the switch 111. The secondary winding 121 is connected to the voltage doubler rectifying unit 13.

In the frequency converter 10 of the embodiment of the present invention, the inverter switch unit 11 is added such that the resonant inductor 112 can be disposed separately from the step-up transformer 12, such that the resonant inductor 112 does not affect the relationship between the primary winding 121 and the secondary winding 122. The magnetic coupling can further improve the energy transmission efficiency of the step-up transformer 12 by strengthening the magnetic coupling capability of the primary winding 121 and the secondary winding 122, thereby improving the overall efficiency of the inverter 10 and ensuring the reliability of the operation of the inverter 10. .

It should be noted that since the resonant inductor 112 can be separately disposed from the step-up transformer 12, when the inverter 10 is in operation, the overall temperature rise of the inverter 10 is not high due to excessive leakage inductance, which reduces the total temperature. The overall temperature rise of the frequency converter 10 ensures the safety of the frequency converter 10 for use. Of course, the manner in which the resonant inductor 112 is disposed separately from the step-up transformer 12 simplifies the connection between the resonant inductor 112 and the step-up transformer 12 to a certain extent, so that the manufacturing cost of the inverter 10 can be reduced to some extent.

In one embodiment, the step-up transformer 12 includes a core assembly 123, a first bobbin 124, and a second bobbin 125. The first skeleton 124 and the second skeleton 125 are hollow. The primary winding 121 is wound around the first skeleton 124. The secondary winding 122 is wound around the second bobbin 125. The second bobbin 125 and the secondary winding 122 are disposed in the first bobbin 124. The magnetic core assembly 123 includes a first magnetic core 1231 and a second magnetic core 1232. The first magnetic core 1231 includes a first pillar 1233. The second magnetic core 1232 includes a second pillar 1234. The first post 1233 and the second post 1234 are bored in the second bobbin 125 and are spaced apart from each other.

Thus, the magnetic coupling capability between the primary winding 121 and the secondary winding 122 is strong, and the first skeleton 124 can separate the primary winding 121 and the secondary winding 122, so that the primary winding 121 and the secondary can be effectively avoided. The stage windings 122 interact with each other while the first core 1231 and the second core 1232 can be detachably connected, which facilitates assembly and disassembly of the core assembly 123.

In one embodiment, the first frame 124 includes two annular first retaining rings 1241 and a first frame 1242 that connects the two first retaining rings 1241. The primary winding 122 is wound around the first frame 1242. The second skeleton 125 includes Two annular second retaining rings 1251 and a second frame 1252 connecting the two second retaining rings 1251. The secondary winding 122 is wound around the second frame 1252.

In this way, the annular retaining ring has a certain protection function for the winding, and the frame body has the functions of protection and support for the winding.

In one embodiment, the first frame 1242 and the second frame 1252 are both hollow cylindrical. The first skeleton 124 and the second skeleton 125 are concentrically arranged. The length of the first skeleton 124 is equal to the length of the second skeleton 125.

In this way, the windings can be evenly wound around the corresponding frame body, and the two skeletons are concentrically arranged to ensure strong magnetic coupling between the primary winding 121 and the secondary winding 122.

In one embodiment, the first retaining ring 1241 is provided with a first notch 1243 at the edge thereof. A second notch 1253 is defined in an edge of the second retaining ring 1251. The primary winding 121 is provided with a first notch 1243. The secondary winding 121 is provided with a second notch 1253.

As such, the winding can be threaded and connected to the circuitry of the frequency converter 10.

In one embodiment, the first core 1231 is U-shaped and the second core 1232 is U-shaped.

Thus, the distribution parameters of the magnetic core are consistent and have a good heat dissipation effect.

In one embodiment, the resonant inductor 112 includes a toroidal core 114 and a winding 115 that is evenly wound around the core 114. The winding 115 is connected to the circuit of the frequency converter 10.

As such, the resonant flux 112 has less flux leakage, and does not interfere with the normal operation of the surrounding devices of the resonant inductor 112 due to the flux leakage, while the inductance of the resonant inductor 112 is stable because the process of the resonant inductor 112 is consistent in batch size. The possibility of poor sex is small.

In one embodiment, the frequency converter 10 includes a rectification unit 14 and an inverter control unit 15. The rectifying unit 14 is connected in parallel with the inverter switching unit 11. The rectifying unit 14 is for converting alternating current into direct current. The inverter control unit 15 is connected in parallel with the inverter switch unit 15 and is used to control the on and off of the switch tube 111.

In this way, the inverter control unit 15 can ensure the stability of the inverter switch unit 11, and can effectively ensure that the switching loss of the switch tube 111 is approximately zero.

In the example of the present invention, the rectifying unit 14 is connected to an alternating current power source 17, and the rectifying unit 14 is for converting the alternating current of the alternating current power source 17 into direct current. In one example, the rectifying unit 14 can include a rectifier bridge.

In one embodiment, the frequency converter 10 includes a filtering unit 16. The filtering unit 16 is connected to the rectifying unit 14 and the inverter control unit 15.

In this way, interference of a specific band frequency can be effectively suppressed and prevented.

Specifically, the filtering unit 16 includes an inductor 161 and a capacitor 162, and the inductor 161 is connected in parallel with the capacitor 162.

The microwave oven 100 of the embodiment of the present invention includes a magnetron 20 and a frequency converter 10 according to any of the above embodiments. The voltage doubler rectifying unit 13 is connected to the magnetron 20.

In the microwave oven 100 of the embodiment of the present invention, the inverter switch unit 11 is added such that the resonant inductor 112 can be disposed separately from the step-up transformer 12 such that the resonant inductor 112 does not affect the magnetic field between the primary winding 121 and the secondary winding 122. Coupling, in turn, enhances the energy transfer efficiency of the step-up transformer 12 by enhancing the magnetic coupling capability of the primary winding 121 and the secondary winding 122, thereby improving the overall efficiency of the frequency converter 10 and ensuring the reliability of the operation of the frequency converter 10.

In the present invention, the first feature "on" or "under" the second feature may include direct contact of the first and second features, and may also include first and second features, unless otherwise specifically defined and defined. It is not in direct contact but through additional features between them. Moreover, the first feature "above", "above" and "above" the second feature includes the first feature directly above and above the second feature, or merely indicating that the first feature level is higher than the second feature. The first feature "below", "below" and "below" the second feature includes the first feature directly below and below the second feature, or merely the first feature level being less than the second feature.

The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and arrangements of the specific examples are described below. Of course, they are merely examples and are not intended to limit the invention. In addition, the present invention may be repeated with reference to the numerals and/or reference numerals in the various examples, which are for the purpose of simplicity and clarity, and do not indicate the relationship between the various embodiments and/or arrangements discussed. Moreover, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the use of other processes and/or the use of other materials.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples", etc. Particular features, structures, materials or features described in the examples are included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms does not necessarily mean the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

While the embodiments of the present invention have been shown and described, the embodiments of the invention may The scope of the invention is defined by the claims and their equivalents.

Claims (13)

A frequency converter for a microwave oven, characterized in that the frequency converter comprises: An inverter switch unit, the inverter switch unit includes a switch tube, a resonant capacitor, and a resonant inductor, and the resonant capacitor is connected between the switch tube and the resonant inductor; a step-up transformer comprising a primary winding and a secondary winding, one end of the primary winding being connected to one end of the resonant capacitor through the resonant inductor, the other end of the primary winding being connected to the The other end of the resonant capacitor and the switch tube; A voltage doubler rectifying unit, the secondary winding being connected to the voltage doubler rectifying unit. The frequency converter according to claim 1, wherein said step-up transformer comprises a core assembly, a first bobbin and a second bobbin, said first bobbin and said second bobbin being hollow, said primary a winding is wound around the first bobbin, the secondary winding is wound around the second bobbin, and the second bobbin and the secondary winding are disposed in the first bobbin The magnetic core assembly includes a first magnetic core including a first post, the second magnetic core includes a second post, and the first post and the second post are pierced In the second skeleton and at intervals. The frequency converter according to claim 2, wherein said first bobbin includes two annular first retaining rings and a first frame connecting said two first retaining rings, said primary winding Provided on the first frame; The second bobbin includes two annular second retaining rings and a second frame connecting the two second retaining rings, and the secondary winding is wound around the second frame. The frequency converter according to claim 3, wherein the first frame body and the second frame body are each in a hollow cylindrical shape, and the first frame and the second frame are concentrically arranged, The length of the first skeleton is equal to the length of the second skeleton. The frequency converter according to claim 3, wherein a first notch is formed in an edge of the first retaining ring, and a second notch is formed in an edge of the second retaining ring, and the primary winding is disposed The first gap is described, and the secondary winding passes through the second gap. The frequency converter according to claim 2, wherein said first magnetic core is U-shaped and said second magnetic core is U-shaped. The frequency converter of claim 1 wherein said resonant inductor comprises a toroidal core and is uniform A winding is wound around the magnetic core, and the winding is inserted into a circuit of the frequency converter. The frequency converter according to claim 1, wherein said frequency converter comprises a rectifying unit and said inverter control unit, said rectifying unit being connected in parallel with said inverter switching unit, said rectifying unit for converting alternating current into Direct current, the inverter control unit is connected in parallel with the inverter switch unit and used to control the on and off of the switch tube. The frequency converter according to claim 8, wherein said rectifying unit is connected to an alternating current power source, and said rectifying unit is configured to convert an alternating current of said alternating current power source into a direct current power. The frequency converter of claim 9 wherein said rectifying unit comprises a rectifier bridge. The frequency converter according to claim 8, wherein said frequency converter comprises a filtering unit, and said filtering unit is connected to said rectifying unit and said inverter control unit. The frequency converter of claim 11 wherein said filtering unit comprises an inductor and a capacitor, said inductor being in parallel with said capacitor. A microwave oven comprising a magnetron and a frequency converter according to any one of claims 1 to 12, said voltage doubler rectifying unit being connected to said magnetron.

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