Rectifier unit and induction cooker having a rectifier unit

Abstract

To provide a rectifier securing cooling performance suitable for an induction heating cooker including a plurality of heating coils.SOLUTION: A rectifier unit is for an induction heating cooker. The rectifier unit comprises: a first rectifier and a second rectifier each having a plurality of terminals and converting a direct current to an alternating current; and a heat sink having a plurality of fins, on which the first rectifier and the second rectifier are attached. The first rectifier and the second rectifier each have an attachment surface. In the first rectifier and the second rectifier, sequences of polarities of the terminals with respect to the attachment surfaces are the same. The heat sink has: a first face facing a substrate when the rectifier unit is mounted on a substrate of the induction heating cooker; and a second face crossing the first face. The attachment surfaces of the first rectifier and the second rectifier are attached to the first face and the second face, respectively. The polarity of each of the terminals of the first rectifier and the polarity of each of the terminals of the second rectifier coincide along a line where the first face and the second face cross each other.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a rectifier unit and an induction heating cooker having the rectifier unit.

Background Art

[0002] An induction heating cooker is a cooker that passes a high-frequency current through a heating coil directly below a top plate on which a pan is placed and performs induction heating on a magnetic body at the bottom of the pan by using magnetic lines of force generated from the heating coil. The high-frequency current is generated using an AC power supply, a rectifier of the induction heating cooker, an inverter circuit, and a control circuit.

[0003] Patent Document 1 discloses a conventional induction heating cooker. Since the switching elements in the rectifier and the inverter circuit each generate heat, they are attached to a heat sink and cooled using the heat sink.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an induction heating cooker having a plurality of heating coils, a rectifier and a switching element for each heating coil are provided, and in order to cope with high output, it is required to effectively cool each of them. Generally, it is considered that each switching element having a relatively large amount of heat generation is preferentially cooled, but it is also required to sufficiently cool the rectifier.

[0006] An object of the present disclosure is to provide a rectifier with ensured cooling performance suitable for an induction heating cooker having a plurality of heating coils.

Means for Solving the Problems

[0007] A rectifier unit according to one aspect of the present disclosure is a rectifier unit for an induction cooker. The rectifier unit comprises a first rectifier and a second rectifier, each having a plurality of terminals and converting alternating current to direct current, and a heat sink having a plurality of fins, to which the first and second rectifiers are mounted. Each of the first and second rectifiers has a mounting surface. In the first and second rectifiers, the order of the polarities of each terminal with respect to the mounting surface is the same. The heat sink has a first surface that faces the substrate when the rectifier unit is mounted on the substrate of the induction cooker, and a second surface that intersects the first surface. The first rectifier is mounted on the first surface on the mounting surface. The second rectifier is mounted on the second surface on the mounting surface. The polarities of each terminal of the first rectifier and the polarities of each terminal of the second rectifier coincide along the line where the first and second surfaces intersect.

[0008] An induction heating cooker according to another aspect of the present disclosure comprises a power supply circuit, a circuit board, the rectifier unit described above on the circuit board, a fan, a first heating coil, a second heating coil, a first inverter circuit on the circuit board that supplies a high-frequency current to the first heating coil, and a second inverter circuit on the circuit board that supplies a high-frequency current to the second heating coil. The rectifier unit is positioned further away from the fan than the first and second inverter circuits. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a rectifier with ensured cooling performance that is suitable for induction cookers having multiple heating coils. [Brief explanation of the drawing]

[0010] [Figure 1] Schematic diagram of an example of an induction heating cooker according to an exemplary embodiment. [Figure 2] Block diagram of the induction cooker configuration shown in Figure 1. [Figure 3] A schematic diagram of a portion of the body of an induction cooker according to an exemplary embodiment. [Figure 4] Enlarged view of the rectifier unit [Figure 5] Perspective view of the rectifier unit [Figure 6] Perspective view of the rectifier unit [Figure 7] Figure 6 shows the first and second rectifiers of the rectifier unit extracted in their original configuration. [Figure 8] Diagram illustrating the positions of terminals with the same polarity in the first and second rectifiers. [Figure 9] Cross-sectional view of the heatsink using the XZ plane. [Figure 10] Schematic diagram showing how heat is transferred from the first and second rectifiers. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described below with reference to the drawings. However, the configurations described below are merely examples of this disclosure, and this disclosure is not limited to the embodiments described below. The technology in this disclosure is not limited thereto, and various modifications, substitutions, additions, and omissions are possible in other embodiments as long as they do not depart from the technical idea of ​​this disclosure, depending on the design, etc.

[0012] While this disclosure is adequately described in relation to preferred embodiments with reference to the accompanying drawings, various modifications and alterations will be obvious to those skilled in the art. Such modifications and alterations should be understood to be included within the scope of this disclosure as defined by the attached claims.

[0013] An induction cooker having a plurality of heating coils uses a rectifier, an inverter circuit, and a control circuit to pass a high-frequency current through each heating coil, and performs induction heating on the magnetic material at the bottom of the pot using the magnetic lines of force generated from the heating coil. More specifically, the rectifier full-wave rectifies an alternating current supplied from a commercial alternating current power source of 50 Hz or 60 Hz and converts it into a direct current. The inverter circuit and the control circuit rapidly switch the direct current to convert it into a high-frequency current of 20 kHz to 30 kHz.

[0014] In order to perform high-power and high-speed switching, for example, an IGBT (Insulated-gate bipolar transistor), which is a type of power semiconductor, is used. Since the IGBT has a relatively high loss watt, it generates a large amount of heat. Therefore, it is necessary to preferentially cool the IGBT. The induction cooker is provided with a fan for cooling the interior, and cooling is performed using the wind generated by the rotation of the fan. In order to preferentially cool the IGBT, generally, the IGBT is attached to a heat sink and arranged at a position relatively close to the fan. Since a plurality of IGBTs are provided to drive a plurality of heating coils, a plurality of IGBTs and heat sinks are arranged near the fan.

[0015] On the other hand, since the rectifier also generates heat, it is necessary to use a heat sink for cooling. However, due to the influence of the arrangement of the above-described plurality of IGBTs and heat sinks, the rectifier and the heat sink will be arranged at a position relatively far from the fan. As a result, the cooling performance of the rectifier may deteriorate.

[0016] Therefore, the inventors of the present application studied a configuration that can efficiently cool the rectifier and handle high power. Conventionally, in an induction heating cooker provided with a plurality of heating coils, power was supplied to a plurality of inverter circuits using a single rectifier. In a configuration using a single rectifier, the amount of heat generated from the single rectifier was large. The inventors of the present application provided a plurality, typically two, rectifiers in parallel instead of the conventional single rectifier. In a configuration using a plurality of rectifiers, by dispersing the heat generation from the plurality of rectifiers, it becomes possible to sufficiently cool each rectifier. As a result, a configuration of a rectifier capable of handling high power can be realized, and it becomes possible to facilitate the implementation in an induction heating cooker.

[0017] The rectifier unit according to the present disclosure is used in an induction heating cooker. The rectifier unit includes a first rectifier and a second rectifier each having a plurality of terminals and converting alternating current to direct current, and a heat sink having a plurality of fins to which the first rectifier and the second rectifier are attached. Each of the first rectifier and the second rectifier has an attachment surface. In the first rectifier and the second rectifier, the order of the polarities of the respective terminals with respect to the attachment surface is the same. The heat sink has a first surface facing the substrate when the rectifier unit is attached to the substrate of the induction heating cooker, and a second surface intersecting the first surface. The first rectifier is attached to the first surface on the attachment surface, and the second rectifier is attached to the second surface on the attachment surface. The polarities of the respective terminals of the first rectifier and the polarities of the respective terminals of the second rectifier are aligned along a line where the first surface and the second surface intersect.

[0018] If two rectifiers are to be attached to the same surface of a single heat sink and connected in parallel, the connection lines of the plurality of terminals of the rectifiers intersect, and the wiring becomes complicated. On the other hand, according to the above configuration of the rectifier unit of the present disclosure, the two rectifiers of the rectifier unit can be connected in parallel on the substrate of the induction heating cooker. Further, since the two rectifiers are attached to the same heat sink, the amount of heat dissipation is also the same, and high power can be handled.

[0019] [[ID=ll]] The induction heating cooker according to this disclosure comprises a power supply circuit, a circuit board, the rectifier unit described above on the circuit board, a fan, a first heating coil, a second heating coil, a first inverter circuit on the circuit board that supplies a high-frequency current to the first heating coil, and a second inverter circuit on the circuit board that supplies a high-frequency current to the second heating coil. The rectifier unit is positioned further away from the fan than the first and second inverter circuits.

[0020] With this configuration, the two inverter circuits can be cooled preferentially, while the two rectifiers can be connected in parallel on the induction cooker's circuit board. Furthermore, since the two rectifiers are mounted on the same heatsink, the heat dissipation is the same, enabling high output and efficient cooling.

[0021] (Embodiment) Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.

[0022] [composition] Figure 1 is a schematic diagram of an example of an induction cooker 1 according to an embodiment of this disclosure. Figure 2 is a block diagram of the configuration of the induction cooker 1 shown in Figure 1. Hereinafter, the induction cooker 1 will be described using Figures 1 and 2. The XYZ coordinate system shown in the figures is included to aid in understanding the invention and is not intended to limit the invention. The X-axis and Y-axis directions indicate the horizontal direction, and the Z-axis direction indicates the vertical direction.

[0023] The induction cooker 1 is a cooker that induces heating of a cooking container C containing a food to be cooked T. In this specification, the cooking container C is described as an example of a food to be heated. The food to be heated is not limited to the cooking container C, but can be any food that is to be induction heated.

[0024] As shown in Figure 1, the induction cooker 1 according to this embodiment comprises a top plate 2, a main body 3, heating coils 4A to 4C, a controller 5, and an input / output interface device 6. The induction cooker 1 also has an electrical circuit that supplies current obtained from a power source to the heating coils 4A to 4C.

[0025] The top plate 2 is a mounting section on which a container can be placed. The top plate 2 is positioned on the upper surface of the main body 3. The top plate 2 is made of a material such as glass that can transmit the magnetic field generated by the heating coils 4A to 4C.

[0026] The main unit 3 contains internal electrical components such as heating coils 4A to 4C, a controller 5, a printed circuit board 10 (described later), a rectifier unit (described later) mounted on the printed circuit board 10, multiple inverter circuits, and a power supply circuit. The main unit 5 also has a top plate 2 on its upper surface and an input / output interface device 6 on its side.

[0027] The heating coils 4A to 4C are heating units for heating the container and are located below the top plate 2. When a high-frequency current is supplied to the heating coils 4A to 4C, they generate an induced magnetic field. The heating coils 4A to 4C heat the bottom surface of the container placed on the top plate 2 with this magnetic field, thereby heating the food to be cooked contained in the container. Hereinafter, in this specification, heating coil 4A and heating coil 4B will also be referred to as the first heating coil 4A and the second heating coil 4B, respectively.

[0028] As shown in Figure 1, by providing three heating coils 4A, 4B, and 4C, the induction cooker 1 can simultaneously heat and cook three objects. Figure 1 shows an example in which one cooking container C containing the object to be heated T is placed on heating coil 4A. The cooking container C may be made of a metal material such as iron, stainless steel, aluminum, or copper.

[0029] Controller 5 is a control device that controls the operation of the induction cooker 1. Specifically, Controller 5 can control the operation of each heating coil 4A to 4C. Controller 5 comprises an arithmetic circuit 7 and a memory device 8.

[0030] The arithmetic circuit 7 executes processing in the controller 5. The arithmetic circuit 7 includes a general-purpose processor such as a CPU or MPU that realizes predetermined functions by executing a program. The arithmetic circuit 7 is configured to communicate with the storage device 8 and realizes various processing in the controller 5 by calling and executing arithmetic programs etc. stored in the storage device 8. Processing in the controller 5 includes, for example, outputting control signals to switching circuits for driving heating coils 4A and 4B. The arithmetic circuit 7 is not limited to a configuration in which hardware resources and software cooperate to realize predetermined functions, but may also be a hardware circuit specifically designed to realize predetermined functions. In other words, the arithmetic circuit 7 can be realized with various processors other than CPUs and MPUs, such as GPUs, FPGAs, DSPs, and ASICs. Such an arithmetic circuit 7 may be composed of, for example, a signal processing circuit which is a semiconductor integrated circuit.

[0031] The storage device 8 is a storage medium capable of storing various types of information. The storage device 8 can be implemented as, for example, memory such as DRAM, SRAM, or flash memory, an HDD, an SSD, or other storage devices, or a combination thereof as appropriate. The storage device 8 stores programs for implementing the various processes performed by the arithmetic circuit 7 as described above.

[0032] The input / output interface device 6 functions as an input device for receiving information from the user and an output device for outputting information to the user. The input / output interface device 6 may include an operation panel for the user to operate the induction cooker 1, buttons for the user to change the heat level, and a display and speaker for informing the user of the status of the induction cooker 1. For example, the user can operate the induction cooker 1 in a predetermined sequence by operating the input / output interface device 6.

[0033] Figure 3 is a schematic diagram of a part of the main body 3 of the induction cooker 1 according to this embodiment. Figure 3 shows the printed circuit board 10 and the fan unit 40. The induction cooker 1 has a power supply circuit that is a 50Hz or 60Hz commercial AC power supply, but this is omitted from Figure 3.

[0034] On the printed circuit board 10, for example, a rectifier unit 50 and two inverter circuits are provided. The rectifier unit 50 includes two rectifiers that full-wave rectify the alternating current supplied from the power supply circuit and convert it into direct current. The two inverter circuits convert the direct current branched from the rectifier unit 50 into high-frequency current and supply it to the heating coils 4A and 4B. Note that rectifiers are sometimes called "diode bridges," "bridge diodes," or "ACDC converters." In this specification, the term "rectifier" will be used.

[0035] Figure 3 illustrates the main components of the two inverter circuits: the first choke coil 26, the second choke coil 27, the first switching element 32A, the second switching element 33A, the third switching element 32B, and the fourth switching element 33B.

[0036] In the induction cooker 1, the controller 5 controls the heating coil 4A to flow a high-frequency current by switching the first switching element 32A and the second switching element 33A on and off. The controller 5 also controls the second heating coil 4B to flow a high-frequency current by switching the third switching element 32B and the fourth switching element 33B on and off.

[0037] The first switching element 32A and the second switching element 33A are both attached to the first heatsink 35A. The third switching element 32B and the fourth switching element 33B are both attached to the second heatsink 35B. The first heatsink 35A and the second heatsink 35B are components intended for cooling by absorbing heat and dissipating it into the air. The first heatsink 35A and the second heatsink 35B are made of metal and absorb the heat generated by the operation of the first to fourth switching elements 32A to 35B, transferring it to the metal, promoting convection of air due to the heat, and dissipating the heat to cool the first to fourth switching elements 32A to 35B.

[0038] The fan unit 40 includes a fan 41 and an air passage wall 42. The fan 41 is rotated by a motor (not shown) to generate airflow, which is sent to two inverter circuits and a rectifier unit 50. In this embodiment, the fan 41 blows air in the direction of arrow W1 shown in Figure 3.

[0039] The air passage wall 42 changes the direction of the air generated by the fan 41. In this embodiment, the air passage wall 42 changes the direction of the air so that it is blown in at least the directions of arrows W2 and W3. In this specification, the air flowing in the directions of arrows W2 and W3 is also referred to as cooling air W2 and W3, respectively.

[0040] The first switching circuit 28A and the second switching circuit 28B are attached to the first heat sink 35A and the second heat sink 35B, respectively, and transfer heat to each heat sink 35A and 35B. Then, each switching circuit 28A and 28B dissipates heat through each heat sink 35A and 35B. The cooling air W2 cools each heat sink 35A and 35B. Therefore, when each heating coil 4A and 4B is driven, the cooling air W2 downstream of each heat sink 35A and 35B may have a higher temperature than upstream of each heat sink 35A and 35B.

[0041] As shown in the figure, the rectifier unit 50 is positioned further from the fan than the first inverter circuit and the second inverter circuit. For example, the rectifier unit 50 is positioned further from the fan 41 than the switching elements 32A and 33A of the first inverter circuit and the switching elements 32B and 33B of the second inverter circuit. The reason for this positioning is to prioritize the cooling of the switching elements 32A and 33A and the switching elements 32B and 33B of the second inverter circuit over the rectifier unit 50. The switching elements 32A and 33A are attached to the heatsink 35A, and the switching elements 32B and 33B are attached to the heatsink 35B, each positioned near the fan 41. Because the heatsinks 35A and 35B are relatively large, the rectifier unit 50 must be installed away from the fan 41.

[0042] However, with the rectifier unit 50 according to this embodiment, sufficient cooling performance can be achieved even if the rectifier unit 50 is installed away from the fan 41. In addition, wiring on the printed circuit board 10 becomes easier.

[0043] Figure 4 is an enlarged view of the rectifier unit 50. Figure 4 shows the rectifier unit 50 as viewed from the +Z to -Z direction. Figures 5 and 6 are perspective views of the rectifier unit 50. Figure 6 is a view of the rectifier unit 50 shown in Figure 5, rotated 90 degrees around the Y-axis.

[0044] The rectifier unit 50 includes a first rectifier 51, a second rectifier 52, and a heat sink 53. The first rectifier 51 and the second rectifier 52 are fixed to a common heat sink 53 with screws S1 and S2, respectively. The first rectifier 51 is fixed to the -Z side surface P1 (sometimes referred to as "first surface P1" in this specification) of the heat sink 53. The second rectifier 52 is fixed to the -X side surface P2 (sometimes referred to as "second surface P2" in this specification) of the heat sink 53. The heat sink 53 has a plurality of plate-shaped fins F. The second surface P2 is the end face of a base member on which the plurality of fins F are arranged, and the plurality of fins F extend from the base member in the +X direction. In the illustrated example, the first surface P1 and the second surface P2 intersect at a right angle, but they do not necessarily have to be at a right angle; they may be less than or greater than 90 degrees.

[0045] Figures 4 and 5 schematically show the direction of the cooling air W3 when the rectifier unit 50 is mounted on the printed circuit board 10 of Figure 3. The cooling air W3 flows from -Y to +Y. The cooling air W3 flows over the surface of the heat sink 53 and / or along the multiple fins F of the heat sink 53.

[0046] As shown in Figures 3 and 4, the multiple fins F are positioned closer to the fan 41 than the second rectifier 52. With this arrangement, as shown in Figure 5, the cooling air W3 from the fan 41 can easily enter the open ends of the multiple fins F. Therefore, the cooling air W3 from the fan 41 can more easily hit the fins F, and the first rectifier 51 and the second rectifier 52 can be effectively cooled.

[0047] Next, the arrangement of the terminals of the first rectifier 51 and the second rectifier 52 will be explained with reference to Figure 7. Figure 7 is a diagram showing the first rectifier 51 and the second rectifier 52 of the rectifier unit 50 shown in Figure 6, extracted in their original arrangement. Figure 7 also shows the line L formed by the intersection of the first surface P1 and the second surface P2 shown in Figure 6. In this embodiment, line L coincides with the direction of the Y axis.

[0048] In this embodiment, the first rectifier 51 and the second rectifier 52 each have multiple terminals 51a to 51d and 52a to 52d. Terminal 51a of the first rectifier 51 is a positive output, terminals 51b and 51c are two AC inputs, and terminal 51d is a negative output. Similarly, terminal 52a of the second rectifier 52 is a positive output, terminals 52b and 52c are two AC inputs, and terminal 52d is a negative output. In other words, the polarity of each terminal of the first rectifier 51 and the polarity of each terminal of the second rectifier 52 coincide along line L.

[0049] The reason for adopting this arrangement is to make it easier to mount the first rectifier 51 and the second rectifier 52 in parallel on the printed circuit board 10. In order to connect them in parallel, the following terminals need to be connected. • One AC input terminal 51b of the first rectifier 51, and one AC input terminal 52b of the second rectifier 52 The other AC input terminal 51c of the first rectifier 51, and the other AC input terminal 52c of the second rectifier 52 • Positive output terminal 51a of the first rectifier 51, positive output terminal 52a of the second rectifier 52 • Negative output terminal 51d of the first rectifier 51, negative output terminal 52d of the second rectifier 52

[0050] Therefore, as in this embodiment, by matching the polarity of each terminal of the first rectifier 51 and the polarity of each terminal of the second rectifier 52 along line L, the routing of the printed circuit board 10 can be shortened and the lines do not cross. Thus, the mounting can be simplified.

[0051] Furthermore, in this embodiment, the first rectifier 51 and the second rectifier 52 are mounted on the heat sink 53 such that the positions of the terminals of the first rectifier 51 and the second rectifier 52, which have the same polarity, coincide with each other in the Y-axis direction.

[0052] Figure 8 illustrates the position of terminals of the same polarity on the first rectifier 51 and the second rectifier 52. Figure 8 shows a virtual plane Q perpendicular to line L, which is formed by the intersection of the first plane P1 and the second plane P2. The first rectifier 51 and the second rectifier 52 are mounted on the heatsink 53 such that both the positive output terminal 51a of the first rectifier 51 and the positive output terminal 52a of the second rectifier 52 lie on this virtual plane Q. Similarly, the positional relationships of the other terminals of the first rectifier 51 and the second rectifier 52 are arranged so that each pair lies on another virtual plane perpendicular to line L. By positioning terminals of the same polarity as close together as possible—in other words, by positioning the first rectifier 51 and the second rectifier 52 close to each other—the wiring length when connecting them in parallel can be shortened, and the heat dissipation amounts of each can be brought closer together, improving cooling efficiency. Furthermore, insertion into a printed circuit board can be improved. This configuration is an example in which the polarity of each terminal of the first rectifier 51 and the polarity of each terminal of the second rectifier 52 are matched along line L.

[0053] If one were to connect two rectifiers in parallel, one might consider a configuration where two rectifiers of the same specifications are placed side-by-side and fixed to a heatsink. However, this configuration presents challenges such as the wiring connecting the positive output terminals being crossed over by the wiring connecting the negative output terminals, and the wiring connecting the AC input terminals becoming complicated.

[0054] One might think that if one rectifier were positioned inverted relative to the other, the wiring could be simplified by connecting the inner terminals first, and then sequentially connecting the outer terminals. However, rectifiers have mounting surfaces, and mounting one rectifier inverted relative to the other is not intended. Furthermore, while it is technically possible to prepare a rectifier with a terminal configuration opposite to that of one rectifier, using such a custom-designed rectifier would increase costs.

[0055] In this embodiment, the specifications of the first rectifier 51 and the second rectifier 52 are the same. In other words, it is sufficient to prepare two identical products of the same model number. Therefore, the polarity order of each terminal relative to the mounting surface is the same for the first rectifier 51 and the second rectifier 52. Even when using such first and second rectifiers 51 and 52, by adopting the mounting method described above, it is possible to achieve a configuration that facilitates parallel connection by avoiding crossing of wires and complicated wiring during parallel connection. Since custom design is not required, it is also possible to suppress the increase in manufacturing costs of the rectifier unit 50. Furthermore, by using two rectifiers with the same specifications, it is also possible to suppress the occurrence of power imbalances that occur when the specifications are different.

[0056] However, the specifications of the first rectifier 51 and the second rectifier 52 do not need to be exactly the same, and it is possible to use multiple types (model numbers) of rectifiers with different specifications or performance, even if the order of the terminal polarities is the same.

[0057] In the example in Figure 8, the terminals of the first rectifier 51 and the second rectifier 52, which have matching polarities, are assumed to be located on the same virtual plane perpendicular to line L. However, two terminals with matching polarities do not necessarily have to be located on the same virtual plane, as long as it is possible to avoid the wires crossing each other or the wiring becoming complicated when connected in parallel.

[0058] Let me explain in detail. Consider the example shown in Figure 8, where the position of the first rectifier 51 remains the same, but the position of the second rectifier 52 is offset in the -Y direction by the width of the second rectifier 52 in the Y-axis direction. In such a configuration, the terminal groups of the first rectifier 51 and the second rectifier 52 are arranged along line L, and the polarity order of the terminal groups of each rectifier is the same along line L. In such a configuration, when the rectifier unit 50 is positioned with the first surface P1 facing the printed circuit board 10, it is sufficient to provide wiring or jumper wires connecting the terminals 51a of the first rectifier 51 and the terminals 52a of the second rectifier 52. The same applies to other terminals. Since the multiple wirings or jumper wires provided in this way do not intersect, parallel connection of the first rectifier 51 and the second rectifier 52 can be easily realized. Note that the above offset amount is just an example and can be determined arbitrarily. These embodiments are also examples of configurations in which the polarity of each terminal of the first rectifier 51 and the polarity of each terminal of the second rectifier 52 are matched along line L.

[0059] In this embodiment, instead of the conventional configuration using a single rectifier, a configuration using multiple (two) rectifiers connected in parallel is adopted. This makes it possible to ensure cooling performance. Furthermore, by mounting the rectifiers to the heatsink so that the polarity order of the terminals of the rectifiers matches, easy mounting to the printed circuit board 10 can be achieved.

[0060] Next, the configuration and heat conduction of the heatsink 53 will be explained with reference to Figures 9 and 10.

[0061] Figure 9 shows a cross-section of the heat sink 53 in the XZ plane. The heat sink 53 has multiple fins F, including a fin group F1 closer to the first surface P1 and a fin group F2 further away from the first surface P1. As shown, the fin length of fin group F1 is shorter than the fin length of fin group F2. This is because the configuration of the base member B on which the multiple fins F are arranged is different.

[0062] The base member B consists of a thick section B1 and a thin section B2. A fin group F1 is arranged on the thick section B1. A fin group F2 is arranged on the thin section B2. The reason for providing the thick section B1 and the thin section B2 is to allow the first rectifier 51 and the second rectifier 52 to be attached to the heat sink 53 using the thick section B1.

[0063] As shown in Figure 9, the thickened portion B1 allows screws S1 and S2 to fit inside. This allows the first rectifier 51 and the second rectifier 52 to be attached with screws. In other words, the heat sink 53 having the thickened portion B1 and the thinned portion B2 has a suitable configuration for connecting two rectifiers in parallel and attaching them to the heat sink 53 with screws.

[0064] Figure 10 schematically illustrates how heat is transferred from the first rectifier 51 and the second rectifier 52. Heat from the first rectifier 51 and the second rectifier 52 is conducted from the base member B to the fin groups F1 and F2 and released into the air. The path length from the heat from the first rectifier 51 and the heat from the second rectifier 52 to either the fin group F1 or F2 is made generally uniform by providing the thickened section B1 and the thinned section B2. In Figure 10, two arrows with the same pattern indicate that the length from either the first rectifier 51 or the second rectifier 52 to either fin group is generally the same. This makes it possible to cool the first rectifier 51 and the second rectifier 52 generally uniformly.

[0065] Furthermore, with respect to the circumferential direction including the first surface P1 and the second surface P2 of the heat sink 53, by making the lengths of the first surface P1 and the second surface P2 substantially the same, it becomes possible to more evenly transfer heat from the first rectifier 51 and the second rectifier 52 to the fin F. [effect] According to the rectifier unit 50 of this embodiment, it is possible to ensure the cooling performance of each rectifier and to easily mount it on the printed circuit board 10.

[0066] (Summary of characteristics) As is clear from the above description, this disclosure includes the following aspects.

[0067] (Aspect 1) A rectifier unit (50) according to one aspect of the present disclosure is a rectifier unit for an induction heating cooker (1). The rectifier unit (50) comprises a first rectifier (51) and a second rectifier (52), each having a plurality of terminals (51a) to (51d) and (52a) to (52d), which convert alternating current to direct current, and a heat sink (53) having a plurality of fins F to which the first rectifier (51) and the second rectifier (52) are attached. Each of the first rectifier (51) and the second rectifier (52) has a mounting surface. In the first rectifier (51) and the second rectifier (52), the order of the polarity of each terminal with respect to the mounting surface is the same. The heat sink (53) has a first surface (P1) that faces the substrate (10) when the rectifier unit (50) is attached to the substrate (10) of the induction cooker (1), and a second surface (P2) that intersects with the first surface (P1). The first rectifier (51) is attached to the first surface (P1) on the mounting surface. The second rectifier (52) is attached to the second surface (P2) on the mounting surface. The polarity of each terminal of the first rectifier (51) and the polarity of each terminal of the second rectifier (52) coincide along the line L where the first surface (P1) and the second surface (P2) intersect.

[0068] This configuration makes it possible to ensure the cooling performance of each rectifier (51, 52) and to easily mount them on the printed circuit board (10).

[0069] (Aspect 2) In the rectifier unit of Aspect 1, the specifications of the first rectifier (51) and the second rectifier (52) are the same.

[0070] (Aspect 3) In the rectifier unit of aspect 1 or 2, the plurality of fins (F) include a group of fins (F1) closer to the first surface (P1) and a group of fins (F2) further away from the first surface (P1), wherein the fin length of the group of fins (F1) closer to the first surface (P1) is shorter than the fin length of the group of fins (F2) further away from the first surface (P1).

[0071] (Aspect 4) In the rectifier unit of aspect 3, the heat sink (53) has a base member (B) on which a plurality of fins (F) are arranged, and the base member (B) includes a thick portion (B1) on which a group of fins (F1) closer to the first surface (P1) is arranged, and a thin portion (B2) on which a group of fins (F2) further away from the first surface (P1) is arranged.

[0072] (Aspect 5) In the rectifier unit of aspect 4, the first rectifier (51) and the second rectifier (52) are mounted on the thickened portion (B1).

[0073] (Aspect 6) In any of the rectifier units of aspects 3 to 5, with respect to the circumferential direction including the first surface (P1) and the second surface (P2) of the heat sink (53), the length of the first surface (P1) and the length of the second surface (P2) are substantially the same.

[0074] (Aspect 7) In any of the rectifier units of aspects 1 to 6, the terminals of the first rectifier (51) and the terminals of the second rectifier (52), which have matching polarities, are located on the same virtual plane perpendicular to the line (L).

[0075] (Aspect 8) In any of the rectifier units of aspects 1 to 6, the terminal groups of the first rectifier (51) and the second rectifier (52) are arranged along line (L), and the polarity order of the terminal groups of each rectifier (51, 52) is the same along line (L).

[0076] (Aspect 9) An induction heating cooker (1) according to one aspect of the present disclosure comprises a power supply circuit, a circuit board (10), a rectifier unit (50) on the circuit board (10) as in any of aspects 1 to 8 described above, a fan (41), first and second heating coils (4A and 4B), a first inverter circuit on the circuit board (10) that supplies a high-frequency current to the first heating coil (4A), and a second inverter circuit on the circuit board (10) that supplies a high-frequency current to the second heating coil (4B). The rectifier unit (50) is positioned further away from the fan (41) than the first inverter circuit and the second inverter circuit.

[0077] (Aspect 10) In the induction heating cooker of aspect 9, the multiple fins are positioned closer to the fan than the second rectifier of the rectifier unit.

[0078] In this specification, terms such as "First," "Second," etc., are used solely for descriptive purposes and should not be understood as expressing or implying relative importance or ranking of technical features. Features designated as "First" and "Second" express or imply that they include one or more such features. [Industrial applicability]

[0079] This disclosure is applicable to cooking appliances such as induction cookers that have a configuration for cooling a rectifier using a heat sink. [Explanation of symbols]

[0080] 1 induction cooker 2 Top Plate 3 Main unit 4A~4C Heating Coil 5 Controllers 10 Printed circuit boards 40 Fan Units 41 Fans 50 Rectifier Unit 51 1st rectifier 52 2nd rectifier 53 Heatsink

Claims

1. A rectifier unit for induction heating cookers, A first rectifier and a second rectifier, each having multiple terminals, which convert AC to DC, A heat sink having multiple fins and to which the first rectifier and the second rectifier are attached. Equipped with, Each of the first rectifier and the second rectifier has a mounting surface, In the first rectifier and the second rectifier, the polarity order of each terminal with respect to the mounting surface is the same. The heat sink has a first surface that faces the substrate when the rectifier unit is attached to the substrate of the induction cooker, and a second surface that intersects with the first surface. The first rectifier is mounted on the first surface of the mounting surface, The second rectifier is mounted on the second surface on the mounting surface, The polarity of each terminal of the first rectifier and the polarity of each terminal of the second rectifier coincide along the line where the first surface and the second surface intersect. Rectifier unit.

2. The rectifier unit according to claim 1, wherein the specifications of the first rectifier and the second rectifier are the same.

3. The rectifier unit according to claim 1, wherein the plurality of fins include a group of fins closer to the first surface and a group of fins further away from the first surface, and the fin length of the group of fins closer to the first surface is shorter than the fin length of the group of fins further away from the first surface.

4. The heat sink has a base member on which the plurality of fins are arranged, The rectifier unit according to claim 3, wherein the base member includes a thick portion on which the fin group closer to the first surface is arranged, and a thin portion on which the fin group further away from the first surface is arranged.

5. The rectifier unit according to claim 4, wherein the first rectifier and the second rectifier are attached to the thickened portion.

6. With respect to the circumferential direction including the first and second surfaces of the heat sink, The rectifier unit according to claim 5, wherein the length of the first surface and the length of the second surface are substantially the same.

7. The rectifier unit according to claim 1, wherein the terminals of the first rectifier and the second rectifier, which have matching polarities, are located on the same virtual plane perpendicular to the line.

8. The rectifier unit according to claim 1, wherein the terminal groups of the first rectifier and the second rectifier are arranged along the line, and the polarity order of the terminal groups of each rectifier is the same along the line.

9. Power supply circuit, circuit board and A rectifier unit on the substrate according to any one of claims 1 to 8, Fans, First heating coil, The second heating coil, A first inverter circuit on the substrate supplies a high-frequency current to the first heating coil, A second inverter circuit on the substrate supplies high-frequency current to the second heating coil and Equipped with, An induction cooker wherein the rectifier unit is positioned further away from the fan than the first inverter circuit and the second inverter circuit.

10. The induction cooker according to claim 9, wherein, with respect to the fan, the plurality of fins are positioned closer than the second rectifier of the rectifier unit.

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