Frequency conversion control power supply and microwave oven

Abstract

The utility model discloses a frequency conversion control power supply. The variable-frequency control power supply comprises a variable-frequency power panel, a radiator, a rectifier and a switching transistor. The variable-frequency power panel is provided with bonding pads and through holes, the bonding pads are arranged on the peripheries of the through holes, the bonding pads comprise a first bonding pad, a second bonding pad and a third bonding pad, and the through holes comprise a first through hole, a second through hole and a third through hole. The radiator is provided with at least one welding column; a welding column of the radiator is inserted into the variable-frequency power panel through the first through hole, and the welding column is welded to the first bonding pad. And pins of the rectifier are inserted into the variable-frequency power panel through the second through holes and the second bonding pads. And a pin of the switch transistor is inserted on the variable-frequency power panel through the third through hole and the third bonding pad. The fixed design of welding the welding columns additionally arranged on the radiator and the welding pads additionally arranged on the variable-frequency power panel is adopted, so that the volume increase of the variable-frequency power panel caused by high voltage when the radiator is fixed by screws can be avoided; the production time can be reduced; and the potential quality hazard of screw skewing can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of microwave frequency conversion control, in particular to a frequency conversion control power supply. Background Art

[0002] Currently, most microwave variable-frequency control power supplies utilize a single-ended LC resonant circuit, achieving microwave variable-frequency control through a single insulated-gate bipolar transistor (IGBT). Due to the high power of the inverter, the IGBT switching transistor requires heat dissipation. IGBTs are typically packaged in an iron shell. Connecting the collector electrode (C) to the IGBT's iron shell increases the IGBT's heat dissipation area.

[0003] In a related variable-frequency control power supply, the IGBT and heat sink are secured to the inverter's printed circuit board (PCB) by first mounting the IGBT on the heat sink and then screwing the heat sink to the inverter board. This mounting method creates direct contact between the IGBT's metal housing, heat sink, and screws. The IGBT's collector C-pole, which is connected to the IGBT's metal housing, carries a high voltage, which also applies to the heat sink and screws. The screws are secured to the underside of the inverter board. As high-voltage components, they require sufficient safety clearance from other components on the board, significantly increasing the board's size.

[0004] In addition, in the production process, the radiator is fixed with screws, and the production end needs to turn the frequency conversion power supply board over and then fix it with screws, which greatly increases the production working hours and also has the quality risk of crooked screws. Utility Model Content

[0005] In view of this, the present invention aims to solve at least one of the problems in the related art to a certain extent. To this end, the purpose of the present invention is to provide a variable frequency controlled power supply and a microwave oven.

[0006] The present application provides a variable frequency control power supply, which includes a variable frequency power supply board, a heat sink, a rectifier, and a switching transistor. The variable frequency power supply board is provided with solder pads and through holes, the solder pads are arranged around the through holes, the solder pads include a first solder pad, a second solder pad, and a third solder pad, and the through holes include a first through hole, a second through hole, and a third through hole. The heat sink is provided with at least one solder column; the solder column of the heat sink is plugged into the variable frequency power supply board through the first through hole, and the solder column is welded to the first solder pad. The pins of the rectifier are plugged into the variable frequency power supply board through the second through hole and the second solder pad. The pins of the switching transistor are plugged into the variable frequency power supply board through the third through hole and the third solder pad.

[0007] In some embodiments, the solder column is soldered to the first solder pad by wave soldering.

[0008] In some embodiments, the pad is made of a thermally conductive material.

[0009] In certain embodiments, the thermally conductive material is copper foil.

[0010] In some embodiments, a fixing hole is opened on a side wall of the heat sink, and the rectifier and the switching transistor are respectively fixedly mounted on the heat sink through the fixing holes.

[0011] In some embodiments, the gate of the switching transistor is located between the emitter of the switching transistor and the collector of the switching transistor, and the emitter of the switching transistor is located at one end close to the rectifier.

[0012] In some embodiments, the switching transistor has three pins, and the three pins are inserted into the variable frequency power supply board through the third through-holes.

[0013] In some embodiments, the welding column is a rivet.

[0014] In some embodiments, the rectifier is a bridge rectifier.

[0015] The present application also provides a microwave oven, which includes a variable frequency controlled power supply according to any one of the above embodiments.

[0016] In this way, the present application adopts a fixing design of welding the welding columns added to the radiator and the welding pads added to the variable frequency power supply board, which can avoid the increase in the volume of the variable frequency power supply board caused by the high voltage attached to the screw fixing the radiator; it can also reduce production hours and eliminate the quality risks caused by crooked screws.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 Schematic diagram of the structure of the variable frequency controlled power supply according to the embodiment of the present application;

[0020] Figure 2 It is a structural diagram of a variable frequency power supply board according to an embodiment of the present application;

[0021] Figure 3 is a schematic structural diagram of a radiator according to an embodiment of the present application;

[0022] Figure 4 This application Figure 3 Schematic cross-section of the radiator along line AA.

[0023] Main components reference numbers:

[0024] Frequency conversion control power supply 100;

[0025] Frequency conversion circuit board 10, heat sink 20, rectifier 30, switching transistor 40, solder pad 50, first solder pad 51, second solder pad 52, third solder pad 53, through hole 60, first through hole 61, second through hole 62, third through hole 63, solder column 70, fixing hole 80, first fixing hole 81, second fixing hole 82, heat dissipation material 90. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0027] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance, or to implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically specified.

[0028] In the description of this utility model, it should be noted that, unless otherwise specified or limited, the terms "installed" and "connected" should be understood in a broad sense and may refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection, or mutual communication; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0030] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0031] See also Figure 1 The present application discloses a variable frequency controlled power supply 100. This power supply 100 is primarily used in microwave devices such as microwave ovens. It heats or processes food or objects by regulating and controlling the power and frequency of the microwaves. The power supply 100 includes a variable frequency power supply board 10, a heat sink 20, a rectifier 30, and a switching transistor 40.

[0032] Specifically, the variable frequency power supply board 10 is the core component of the variable frequency controlled power supply 100, responsible for controlling the power supply's frequency and voltage output. The heat sink 20 is used to reduce the temperature of the variable frequency power supply board 100 and other key components, ensuring stable operation of the power supply. The rectifier 30 converts AC power to DC power, providing a stable DC power supply for the variable frequency controlled power supply board 10. The switching transistor 40 acts as a switch and current regulator in the variable frequency controlled power supply 100.

[0033] Currently, the heat sink is secured to the VFD board with screws, which results in high voltage on both the heat sink and the screws. Since the screws are high-voltage components, they require adequate safety clearance from other components on the VFD board, significantly increasing the board's size. Furthermore, screws are used to secure the heat sink, requiring the board to be flipped over before the screws are installed, significantly increasing production time and creating quality issues such as skewed screws.

[0034] In view of the shortcomings of the above-mentioned radiator fixed with screws, the embodiment of the present application adopts a new fixing method to improve the shortcomings. Figure 1 and Figure 2The variable frequency power supply board 10 is provided with a soldering pad 50 and a through-hole 60. The soldering pad 50 is arranged around the through-hole 60. The soldering pad 50 includes a first soldering pad 51, a second soldering pad 52, and a third soldering pad 53. The through-hole 60 includes a first through-hole 61, a second through-hole 62, and a third through-hole 63. The heat sink 20 is provided with at least one soldering column 70. The soldering column 70 of the heat sink 20 is plugged into the variable frequency power supply board 10 through the first through-hole 61, and the soldering column 70 is welded to the first soldering pad 51. The pins of the rectifier 30 are plugged into the variable frequency power supply board 10 through the second through-hole 62 and the second soldering pad 52. The pins of the switching transistor 40 are plugged into the variable frequency power supply board 10 through the third through-hole 63 and the third soldering pad 53.

[0035] Solder pads 50 are small metal pieces used in the electronics manufacturing industry to connect electronic components or traces on one side of a circuit board to the other. Solder pads 50, which can be made of brass or steel, serve as the physical interface for electronic components and are connected to other electronic components through soldering. In the variable frequency power supply board 10, solder paste is heated and melted using a soldering iron or heat gun, and then solder pads 50 are connected to the electronic components. During the installation of the heat sink 20, the first solder pad 51 serves as the soldering foundation for the fixing points of the heat sink 20.

[0036] Through-holes 60 are located on the circuit board and are used to connect conductive paths between different layers and allow component pins to pass through. In this embodiment, first through-holes 61 are used to insert solder posts 70, which secure the heat sink 20 to the variable-frequency power supply board 10. Solder posts 70 are key components for connecting the heat sink 20 to the circuit board. Typically, they are metal posts that are inserted into first through-holes 61 and soldered to first solder pads 51, thereby securing the heat sink 20 to the variable-frequency power supply board 10.

[0037] The soldering pin 70 of the heat sink 20 is inserted into the variable frequency power supply board 10 through the first through-hole 61 and soldered to the first soldering pad 51. The pins of the rectifier 30 are inserted into the variable frequency power supply board 10 through the second through-hole 62 and the second soldering pad 52. The pins of the switching transistor 40 are inserted into the variable frequency power supply board 10 through the third through-hole 63 and the third soldering pad 53. The soldering process is illustrated here using the soldering pin 70 and the first soldering pad 51 as an example. First, insert the soldering pin 70 into the first through-hole 61 of the variable frequency power supply board 10. This ensures a physical connection between the heat sink 20 and the variable frequency power supply board 10. Then, use a soldering tool (such as a soldering gun or iron) to melt solder (such as tin) and apply it to the connection between the soldering pin 70 and the first soldering pad 51. As the solder cools and solidifies, it forms a strong electrical and mechanical connection between the soldering pin 70 and the first soldering pad 51.

[0038] It should be noted that during the welding process, it is necessary to ensure that the welding column 70 is fully inserted into the through hole 61 and is in close contact with the first welding pad 51. After welding is completed, it is necessary to check whether the welding point is firm and perform necessary tests to ensure the reliability of the connection.

[0039] Understandably, current technology uses screws to secure the heat sink. Because the IGBT housing, heat sink, and screws are all in direct contact, the high voltage at the collector C pole of the IGBT, which is connected to the housing, also carries high voltage, which in turn causes high voltage to be applied to the heat sink and screws. The screws are secured to the bottom surface of the inverter power board. As high-voltage components, they require sufficient safety clearance from other components on the board, significantly increasing the board's size.

[0040] Therefore, the design of soldering the solder posts 70 added to the heat sink 20 to the solder pads 50 added to the variable frequency power board 10 ensures a stable connection between the heat sink 20 and the variable frequency power board 10, ensuring the normal operation and heat dissipation of the variable frequency power board 10 while avoiding the increased size of the variable frequency power board caused by the high voltage associated with screw-fixed heat sinks. The production end no longer needs to flip the variable frequency power board 10 before screwing it in, effectively reducing production time, avoiding the quality risk of crooked screwing, and improving production efficiency and quality.

[0041] In some embodiments, the solder pillar 70 is soldered to the first solder pad 51 by wave soldering.

[0042] Specifically, wave soldering is an efficient electronic soldering method that uses a wave of high-temperature liquid tin (solder) to simultaneously solder multiple solder joints. In the production of microwave oven circuit boards, wave soldering technology is used to connect solder column 70 to first solder pad 51.

[0043] In detail, the wave soldering process can be divided into a preparation stage, a preheating stage, a wave soldering stage, a cooling stage and a detection stage.

[0044] Preparation stage: Insert the soldering column 70 into the through hole 60 of the variable frequency power supply board 10, and ensure that the soldering column 70 is aligned with the first soldering pad 51. Before soldering, it may be necessary to pre-apply a layer of flux on the first soldering pad 51 to improve the soldering quality.

[0045] Preheating: The VFD board 10 is fed into the wave soldering machine and passed through the preheating zone. The preheating zone is typically controlled at 90-100°C and is approximately 1-1.2 meters long. The purpose of preheating is to raise the temperature of the PCB and activate the soldering flux, thereby minimizing thermal shock when the assembly enters the wave soldering process.

[0046] Wave soldering: When the variable frequency power supply board 10 passes through the wave soldering machine, it comes into contact with a wave of high-temperature liquid tin. The temperature of the soldering area is typically between 220-240°C. The wave soldering machine sprays the liquid tin into a solder wave of the required design. This wave forms an electrical and mechanical connection between the solder pillar 70 and the first solder pad 51.

[0047] Cooling stage: After welding is completed, the variable frequency power supply board 10 will pass through the cooling zone to allow the solder joints to cool down and solidify quickly.

[0048] Inspection and trimming stage: After the welding is completed, the welding points need to be inspected to ensure the welding quality. If necessary, the excess plug-in pins need to be trimmed to ensure the neatness and safety of the variable frequency power supply board 10.

[0049] The present application utilizes wave soldering to solder the solder pillar 70 and the first solder pad 51. This allows for simultaneous soldering of multiple solder joints, significantly improving production efficiency and completing the soldering process in a short period of time, making it suitable for large-scale production. Wave soldering also ensures soldering quality and consistency by controlling soldering parameters and equipment, resulting in high soldering accuracy and repeatability.

[0050] In some embodiments, the pad 50 is composed of a thermally conductive material.

[0051] Specifically, the pad 50 made of thermally conductive material can reduce thermal resistance, enhance heat conduction efficiency, and ensure that the heat generated by heat sources such as IGBTs can be quickly and effectively conducted to the heat sink 20, thereby improving the heat dissipation performance of the entire system.

[0052] That is, by selecting a suitable thermal conductive layer material and adopting a suitable manufacturing process, the present application can significantly improve the heat dissipation performance of the pad 50 and ensure the stable operation of the entire system.

[0053] In addition, a large area of ​​heat dissipation material 90 is laid between each pad 50. The heat dissipation material 90 can be copper foil. On the one hand, the copper foil is used to absorb the excessive current of the collector C pole of the IGBT, and on the other hand, the copper foil is used to dissipate the heat of the IGBT.

[0054] In certain embodiments, the thermally conductive material is copper foil.

[0055] Specifically, the thermal conductivity of copper foil is as high as 401W / (m·K). The high thermal conductivity means that copper foil can quickly transfer heat from the heat source to the heat sink 20, effectively reducing the operating temperature of the variable frequency power supply board 10. The heat capacity of copper foil is close to 0, which enables it to quickly absorb or release heat, which is very beneficial for application scenarios that require high-speed heat transfer. Copper foil not only has good thermal conductivity, but also has a low resistivity, which helps to reduce power loss. Copper foil as a thermal conductive material can significantly improve the heat dissipation performance of the pad 50, ensuring the stable operation of the variable frequency power supply board 10, while also having the advantages of high cost-effectiveness and low processing difficulty.

[0056] In some embodiments, a fixing hole 80 is defined on a side wall of the heat sink 20 , and the rectifier 30 and the switching transistor 40 are fixedly mounted on the heat sink 20 through the fixing holes 80 .

[0057] Specifically, see Figure 3 The fixing holes 80 are divided into a first fixing hole 81 and a second fixing hole 82. The first fixing hole 81 is the rectifier fixing hole, and the second fixing hole 82 is the switching transistor fixing hole. The rectifier 30 and the switching transistor 40 are fixedly mounted on the heat sink 20 through the fixing holes 80. First, place the rectifier 30 and the switching transistor 40 on the predetermined mounting position on the heat sink 20 to ensure close contact with the heat sink 20. Secondly, check whether the fixing holes 80 on the rectifier 30 and the switching transistor 40 are aligned with the fixing holes on the heat sink 20. Finally, use a screwdriver, screws or other fixing parts to fix the rectifier 30 and the switching transistor 40 to the heat sink 20 through the fixing holes 80.

[0058] Also, see Figure 4 , Figure 4 This application Figure 3 A schematic cross-sectional view of the heat sink 20 along line AA. Figure 3 The unique shape of heat sink 20 and the overall layout of the fins can be seen in the figure. The heat sink is a crucial component of heat sink 20 and is typically made of a metal material, such as aluminum or copper, that provides excellent thermal conductivity. The upper fins of heat sink 20 are arranged longitudinally and parallel to each other, while the lower fins are arranged transversely. This layout facilitates the alignment and attachment of rectifier 30 and switching transistor 40 to heat sink 20, ensuring even heat dissipation into the air and improving heat dissipation efficiency.

[0059] In some embodiments, the gate of the switching transistor 40 is located between the emitter of the switching transistor 40 and the collector of the switching transistor 40 , and the emitter of the switching transistor 40 is located at one end close to the rectifier 30 .

[0060] Specifically, in some embodiments, the switching transistor 40 may be an IGBT. To reduce the size of the variable frequency power supply board 10, the present embodiment designs the IGBT pins. Currently, the order of the relevant IGBT pins from left to right is gate G, collector C, and emitter E. The G and E poles are weak current control terminals, while the C pole is a strong current high voltage and high current terminal. The strong current pin C is located between the weak current pins G and E, requiring a sufficiently wide safety spacing. Furthermore, the emitter E is located away from one end of the rectifier 30, making the PCB layout extremely complex.

[0061] The IGBT pin design in the embodiment of the present application chooses to design the strong and weak current pins separately. The order of the IGBT pins from left to right is emitter E, gate G, and collector C. At the same time, the emitter E end is close to one end of the rectifier 30, which simplifies the PCB layout, reduces the PCB area, improves the heat dissipation efficiency, and improves the reliability of the variable frequency power supply.

[0062] In this way, the present application reduces the PCB area through IGBT pin design and PCB layout design, uses PCB copper foil to dissipate heat to the IGBT, reduces the IGBT temperature, and improves the reliability of the variable frequency power supply.

[0063] In some embodiments, the switch transistor 40 has three pins, which are inserted into the variable frequency power supply board 10 through the third through holes 63 .

[0064] Specifically, find the third through-hole 63 on the variable frequency power supply board 10 that matches the pins of the switch and transistor 40. Align the pins, ensuring that the three pins of the transistor are aligned with the slots to avoid bending or damaging the pins. Insert the pins of the switching transistor 40 into the corresponding third through-hole 63, ensuring that the pins are in close contact with the third through-hole 63. Soldering or other fixing methods can be used to firmly fix the switching transistor 40 to the variable frequency power supply board 10. Correct pin insertion not only ensures the normal operation of the switching transistor 40, but also has important significance for the stability and reliability of the entire power supply circuit.

[0065] In some embodiments, the welding column 70 is a rivet. A rivet is a metal part used to connect two or more parts, and it usually has a head and a rod. The rivet welding column can produce a high-strength connection effect at the connection point through a special structural design. It is more secure and reliable than traditional bolts or welding in certain specific scenarios, and can withstand greater tension and shear forces. Screw fixation requires the production end to turn over the frequency conversion power supply board and then fix it with screws, which greatly increases the production time and also has the quality risk of the screws being skewed. Compared with manual screw fixation, the installation process of the rivet welding column is simpler and more convenient. No complex equipment or professional skills are required. Only special tools are needed to complete the connection. The installer can complete the connection work quickly, reducing installation time and labor costs.

[0066] In some embodiments, the rectifier 30 is a bridge rectifier. A bridge rectifier is used in the variable frequency power supply board 10 to convert AC power into DC power. A bridge rectifier is a rectifier device consisting of two or four diodes. A full-bridge rectifier consists of four diodes and has four ports, one for AC input and one for DC output. A bridge rectifier consists of four rectifier silicon chips connected in a bridge pattern and encapsulated in insulating plastic. High-power bridge rectifiers can also be encapsulated in a zinc metal shell outside the insulation layer to enhance heat dissipation.

[0067] The present application also provides a microwave oven, which includes a variable frequency controlled power supply 100 according to any of the above embodiments. Specifically, the structure of the variable frequency controlled power supply 100 is as described above and will not be repeated here.

[0068] In this way, the wave soldering fixing design of the solder columns added to the radiator and the solder pads added to the variable frequency power supply board can avoid the increase in the volume of the variable frequency power supply board caused by the high voltage attached to the screw fixing the radiator; it can also reduce production hours and eliminate the quality risks of crooked screws.

[0069] The above embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A variable frequency controlled power supply, characterized in that: The variable frequency control power supply includes a variable frequency power supply board, a heat sink, a rectifier and a switching transistor; The variable frequency power supply board is provided with pads and through holes, the pads are arranged around the through holes, the pads include a first pad, a second pad and a third pad, and the through holes include a first through hole, a second through hole and a third through hole; The heat sink is provided with at least one welding column; The soldering column of the heat sink is plugged into the variable frequency power supply board through the first through hole, and the soldering column is soldered to the first soldering pad; The pins of the rectifier are plugged into the variable frequency power supply board through the second through holes and the second solder pads; The pin of the switching transistor is plugged into the variable frequency power supply board through the third through hole and the third soldering pad.

2. The variable frequency controlled power supply according to claim 1, characterized in that: The soldering column is soldered to the first soldering pad in a wave soldering manner.

3. The variable frequency controlled power supply according to claim 1, characterized in that: The solder pad is made of thermally conductive material.

4. The variable frequency controlled power supply according to claim 3, characterized in that: The thermally conductive material is copper foil.

5. The variable frequency controlled power supply according to claim 1, characterized in that: The side wall of the radiator is provided with fixing holes, and the rectifier and the switching transistor are respectively fixedly mounted on the radiator through the fixing holes.

6. The variable frequency controlled power supply according to claim 1, characterized in that: The gate of the switching transistor is located between the emitter of the switching transistor and the collector of the switching transistor, and the emitter of the switching transistor is located at one end close to the rectifier.

7. The variable frequency controlled power supply according to claim 1, characterized in that: The switch transistor has three pins, and the three pins are inserted into the variable frequency power supply board through the third through holes.

8. The variable frequency controlled power supply according to claim 1, characterized in that: The welding column is a rivet.

9. The variable frequency controlled power supply according to claim 1, characterized in that: The rectifier is a rectifier bridge stack.

10. A microwave oven, characterized in that: The microwave oven comprises the variable frequency controlled power supply according to any one of claims 1 to 9.

Images