An integrated inductor and a power converter

Abstract

Embodiments of the present application disclose an integrated inductor, which is used to solve the problems of excessive cost, volume, and weight of the inductor structure in existing multiphase power converters. The magnetic core in the integrated inductor includes N - 1 first magnetic posts and N second magnetic posts. N windings are respectively arranged on the N second magnetic posts. The magnetic permeability of the first magnetic posts is greater than that of the second magnetic posts, and N is a positive integer greater than 2. The N - 1 first magnetic posts and the N second magnetic posts are all parallel to the first direction and are alternately arranged along the second direction perpendicular to the first direction, so that any two adjacent second magnetic posts among the N second magnetic posts are separated by one of the N - 1 first magnetic posts. The magnetic core further includes a first magnetic yoke provided at the first end of each of the N second magnetic posts and a second magnetic yoke provided at the second end, wherein the first magnetic yoke and / or the second magnetic yoke are respectively bonded to the second magnetic posts.

Description

Technical Field

[0001] This application relates to the technical field of inductors, and in particular to an integrated inductor and a power converter. Background Art

[0002] There are generally relatively serious ripples in a multiphase power converter, and excessive ripples will cause losses or even damage to electrical equipment. In order to protect the power converter, it is necessary to suppress the ripples in the circuit.

[0003] The prior art provides an inductor structure in each phase circuit of a power converter. The inductor structure includes a winding and a magnetic core. The magnetic core includes two magnetic posts and a magnetic yoke connecting the two magnetic posts. The winding is wound around the two magnetic posts by a single wire.

[0004] As the power level of the multiphase power converter continues to increase, the cost, volume, and weight of the inductor structure for suppressing ripples in each phase circuit increase significantly, increasing the cost of the power converter and reducing its power density. Summary of the Invention

[0005] Embodiments of this application provide an integrated inductor to solve the problem of excessive cost, volume, and weight of the inductor structure in the existing multiphase power converter, thereby reducing the cost of the power converter and increasing its power density.

[0006] To solve the above technical problems, embodiments of this application provide the following technical solutions:

[0007] In a first aspect, embodiments of this application provide an integrated inductor, including a magnetic core and N conductive windings (referred to as windings for short). Each winding is wound by a single wire and has two wire ends extending therefrom. The magnetic core includes N - 1 first magnetic posts and N second magnetic posts. The N windings are correspondingly arranged on the N second magnetic posts. The magnetic permeability of the first magnetic posts is greater than that of the second magnetic posts, and N is a positive integer greater than 2. The N - 1 first magnetic posts and the N second magnetic posts are all parallel to a first direction, and the N - 1 first magnetic posts and the N second magnetic posts are alternately arranged along a second direction perpendicular to the first direction, such that any two adjacent second magnetic posts among the N second magnetic posts are separated by one of the N - 1 first magnetic posts. The magnetic core further includes a first magnetic yoke provided at the first end of each of the N second magnetic posts and a second magnetic yoke provided at the second end. The first magnetic yoke and the second magnetic yoke are used to transmit the magnetic induction lines generated by the windings in the second magnetic posts into the first magnetic posts.

[0008] Among them, the first magnetic yoke can be arranged at the first end of the second magnetic post by bonding with the first end of the second magnetic post, and the second magnetic yoke can be arranged at the second end of the second magnetic post by other means. For example, the second magnetic post and the second magnetic yoke can be obtained in a single one-piece molding process.

[0009] Alternatively, the second magnetic yoke can be arranged at the second end of the second magnetic post by bonding with the second end of the second magnetic post, and the first magnetic yoke can be arranged at the first end of the second magnetic post by other means. For example, the second magnetic post and the first magnetic yoke can be obtained in a single one-piece molding process.

[0010] Alternatively, the first magnetic yoke can be arranged at the first end of the second magnetic post by bonding with the first end of the second magnetic post, and the second magnetic yoke can be arranged at the second end of the second magnetic post by bonding with the second end of the second magnetic post.

[0011] By integrating the inductance structures in the multi-phase circuits of the power converter, it is beneficial to reduce the cost, volume, and weight of the inductance structures in the multi-phase power converter, thereby reducing the cost of the power converter and increasing its power density.

[0012] In a possible implementation, the N second magnetic posts can share a first magnetic yoke, and the first magnetic yoke can be obtained by one molding.

[0013] Alternatively, in a possible implementation, the N second magnetic posts can share a second magnetic yoke, and the second magnetic yoke can be obtained by integral molding.

[0014] Alternatively, in a possible implementation, the N second magnetic posts can share a first magnetic yoke, and the first magnetic yoke can be obtained by one molding, and the N second magnetic posts share a second magnetic yoke, and the second magnetic yoke is obtained by integral molding.

[0015] Alternatively, in a possible implementation, M adjacent second magnetic posts among the N second magnetic posts share a first magnetic yoke, and the other N - M second magnetic posts each correspond to a first magnetic yoke. Alternatively, in a possible implementation, M adjacent second magnetic posts among the N second magnetic posts share a second magnetic yoke, and the other N - M second magnetic posts each correspond to a second magnetic yoke. M is a positive integer greater than 1 and less than N.

[0016] Based on the N second magnetic posts sharing a first magnetic yoke and a second magnetic yoke, in a possible implementation, N - 1 first magnetic posts can be arranged between the first magnetic yoke and the second magnetic yoke. In a possible implementation, the N - 1 first magnetic posts can be arranged between the first magnetic yoke and the second magnetic yoke by bonding.

[0017] In a possible implementation, each of the N second magnetic posts may respectively correspond to a first magnetic yoke and a second magnetic yoke, wherein the two ends of the N - 1 first magnetic posts are flush with the first magnetic yoke and the second magnetic yoke respectively.

[0018] In a possible implementation, each of the N - 1 first magnetic posts is made of multiple layers of strip materials.

[0019] In a possible implementation, the plane of any layer of the multiple layers of strip materials is parallel to the first direction and the second direction.

[0020] In a possible implementation, the multiple layers of strip materials are amorphous strip materials or nanocrystalline strip materials.

[0021] In a possible implementation, the number of turns of the middle winding among the N windings is less than that of the other windings. The middle winding is disposed on the second magnetic post located between any two of the N - 1 first magnetic posts, and the other windings are the other windings among the N windings except the middle winding.

[0022] In a possible implementation, the cross-sectional area of the middle magnetic post among the N second magnetic posts on a first plane perpendicular to the first direction is less than the cross-sectional areas of the other second magnetic posts on the first plane. The middle magnetic post is the second magnetic post located between any two of the N - 1 first magnetic posts, and the other second magnetic posts are the other second magnetic posts among the N second magnetic posts except the middle magnetic post.

[0023] In a possible implementation, the magnetic permeabilities of the materials of the second magnetic posts, the first magnetic yokes, and the second magnetic yokes are close.

[0024] Alternatively, in a possible implementation, the first magnetic yoke is made of the same material as the second magnetic post (referred to as the first material), that is, the material of the first magnetic yoke is the same as that of the second magnetic post; or, in a possible implementation, the second magnetic yoke is made of the same material as the second magnetic post (referred to as the first material), that is, the material of the second magnetic yoke is the same as that of the second magnetic post; or, in a possible implementation, both the first magnetic yoke and the second magnetic yoke are made of the same material as the second magnetic post (referred to as the first material), that is, the materials of the first magnetic yoke, the second magnetic yoke, and the second magnetic post are all the same. In a possible implementation, the first material is a powder core material or a ferrite air gap composite material.

[0025] In a second aspect, an embodiment of the present application provides a power converter, which includes N switching bridge arms and an integrated inductor as described in the first aspect or any possible implementation manner of the first aspect. The integrated inductor includes N windings, and the N switching bridge arms correspond to the N windings in the integrated inductor one by one. Moreover, the midpoint of each switching bridge arm among the N switching bridge arms is connected to the AC input terminal or the AC output terminal of the power converter through one winding corresponding to this switching bridge arm among the N windings. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of an existing three-phase inverter;

[0027] Figure 2a is a schematic diagram of the first-stage inductor in an existing three-phase inverter;

[0028] Figure 2b is Figure 2a a schematic diagram of the equivalent magnetic circuit in the magnetic core when the winding in the first-stage inductor in

[0029] Figure 3a is a schematic diagram of an existing integrated inductor;

[0030] Figure 3b is Figure 3a a schematic diagram of the equivalent magnetic circuit in the magnetic core when the winding 311A in

[0031] Figure 3c is a schematic diagram of the current waveform output by the winding of the integrated inductor without considering the inter-phase coupling;

[0032] Figure 3d is a schematic diagram of the current waveform output by the winding of the integrated inductor considering the inter-phase coupling;

[0033] Figure 4a is a schematic diagram of an embodiment of the integrated inductor provided by the present application;

[0034] Figure 4b is Figure 4a a schematic diagram of the equivalent magnetic circuit in the magnetic core when the winding 411A in

[0035] Figure 4c is Figure 4a a schematic diagram of the equivalent magnetic circuit in the magnetic core when the winding 411B in

[0036] Figure 4d is Figure 4a a possible bottom view of the integrated inductor in

[0037] Figure 4e is a schematic diagram of another embodiment of the integrated inductor provided by the present application;

[0038] Figure 4f It is a schematic diagram of another embodiment of the integrated inductor provided by this application;

[0039] Figure 4g It is a schematic diagram of another embodiment of the integrated inductor provided by this application;

[0040] Figure 5a is Figure 4b a possible partial schematic diagram of;

[0041] Figure 5b is Figure 4b another possible partial schematic diagram of. Specific embodiments

[0042] A polyphase circuit (three-phase or more) generally includes multiple AC input terminals, or includes multiple AC output terminals, or includes multiple AC input terminals and multiple AC output terminals to input or output alternating current with the same frequency and different phases. There are generally three basic types of polyphase power converters, namely polyphase rectifiers, polyphase inverters, and polyphase cycloconverters. Among them, a polyphase rectifier is used to convert polyphase alternating current input from multiple AC input terminals into direct current; a polyphase inverter is used to convert direct current into polyphase alternating current and output it via multiple AC output terminals; a polyphase cycloconverter is used to convert polyphase alternating current of one frequency input from multiple AC input terminals into polyphase alternating current of another frequency (i.e., AC-AC frequency conversion), or to convert polyphase alternating current with a fixed voltage (or power) into polyphase alternating current with another voltage (or power) (i.e., AC voltage regulation and AC power regulation), and output it via multiple AC output terminals.

[0043] A polyphase power converter generally includes multiple parallel switch bridge arms, and the midpoints of the multiple switch bridge arms are respectively connected to multiple AC input terminals or multiple AC output terminals of the polyphase power converter.

[0044] Ripple is a high-frequency AC component superimposed on a DC or AC steady quantity. The composition of the ripple is relatively complex, and its form is generally a harmonic wave similar to a sine wave with a frequency higher than the power frequency (50 Hz in China), and the other is a pulse wave with a very narrow width.

[0045] Excessive ripple will cause losses or even damage to electrical equipment. There is generally relatively serious ripple in a polyphase power converter (such as a polyphase inverter). In order to suppress the ripple in the polyphase power converter, multiple inductors are generally provided in the polyphase power converter to suppress the ripple in each phase of the alternating current. Specifically, the midpoint of a switch bridge arm is connected to the output terminal of the polyphase power converter through this inductor.

[0046] The power of a multiphase power converter is generally large. Therefore, this inductor is generally a power inductor. The inductors in general electronic circuits can only pass a small current and withstand a low voltage; while the power inductors in power converters are generally wound with thick wires and can withstand alternating currents of dozens, hundreds, thousands, or even tens of thousands of amperes, mainly playing a filtering and oscillating role in the circuit.

[0047] Taking a three-phase inverter as an example below, a power inductor for suppressing the ripple of the alternating current in each phase of a multiphase power electronic device is introduced.

[0048] Figure 1 is a structural schematic diagram of a three-phase inverter. As Figure 1 shown, the inverter 100 includes an inversion unit 110 and a filtering unit 120. The input end of the inversion unit 110 ( Figure 1 represented by "in" in the figure) is used to connect to a DC power supply ( Figure 1 represented by "Vin" for the DC power supply in the figure). The inversion unit 110 includes three parallel switch bridge arms (corresponding to the circuits within the dashed boxes 1101, 1102, and 1103 in Figure 1 the figure respectively). The three parallel switch bridge arms are respectively used to convert the input direct current into alternating currents with the same frequency but different phases, and output the corresponding alternating currents through their respective midpoints ( Figure 1 represented by "a1", "b1", and "c1" respectively for the three midpoints in the figure); the filtering unit 120 includes three inductor-capacitor-inductor (abbreviated as LCL) structures. Specifically, L1-1, C1, and L1-2 form an LCL, L2-1, C2, and L2-2 form an LCL, and L3-1, C3, and L3-2 form an LCL. The input ends of the three LCL structures ( Figure 1 represented by "a2", "b2", and "c2" respectively for the three input ends in the figure) are respectively connected to the three output ends of the inversion unit 110 (i.e., the midpoints of the three switch bridge arms). Each LCL structure is used to filter one path of the input alternating current and output the filtered alternating current through the output end of this LCL structure ( Figure 1 represented by "a3", "b3", and "c3" respectively for the output ends of the three LCL structures, that is, the three AC output ends of the three-phase inverter). For example, the filtered alternating current is output to the power grid.

[0049] Each LCL structure of the filtering unit 120 includes two inductors L. The inductor closer to the input end ("a2" or "b2" or "c2") is called the first-stage inductor, Figure 1 L1-1, L2-1, and L3-1 in the figure are all first-stage inductors; the inductor closer to the output end ("a3" or "b3" or "c3") is called the second-stage inductor, Figure 1L1-2, L2-2, and L3-2 in it are all second-stage inductors. Among them, the first-stage inductor is mainly used to suppress the ripple in the circuit.

[0050] Each first-stage inductor of the existing three-phase inverter adopts Figure 2a the inductor structure 200 shown. The inductor structure 200 includes a winding 210 and a magnetic core ( Figure 2a the rectangle filled with black dots in it represents the magnetic core). The magnetic core includes two magnetic columns 221 and a magnetic yoke 222 connecting the two magnetic columns. The winding 210 is wound around the two magnetic columns 221 by a single wire, and the winding 210 extends two wire ends, Figure 2a the two wire ends of the winding 210 are represented by 210a and 210b respectively in it.

[0051] Figure 2b is a schematic diagram of the equivalent magnetic circuit in the magnetic core when the winding 210 is energized. When the winding 210 is energized, a magnetic field is generated in the magnetic column 221. In Figure 2b it, the arrow on the winding 210 represents the current direction in the winding, and the dotted line with an arrow represents the magnetic induction line in the magnetic core. The magnetic induction line is used to describe the magnetic field generated by the winding 210. The magnetic induction line is a closed curve, and the magnetic induction line always takes the path with the smallest magnetic resistance (i.e., the largest magnetic permeability). Since the magnetic permeability of the magnetic yoke 222 is greater than that of air, therefore, the magnetic induction lines generated by the winding 210 in the magnetic column 221 are transmitted along the magnetic yoke 222 and form a closed curve in the magnetic core.

[0052] As the power level of the three-phase inverter continues to increase, the cost, volume, and weight of the first-stage inductor (such as Figure 2a shown) in each phase circuit of it increase significantly, increasing the cost of the three-phase inverter and reducing its power density.

[0053] In order to reduce costs, some studies have proposed using an integrated inductor 300 as shown in Figure 3a to provide three first-stage inductors for the three-phase inverter simultaneously. As shown in Figure 3a the integrated inductor 300 includes three windings (windings 311A, 311B, and 311C respectively) and a magnetic core ( Figure 3a the rectangle filled with black dots in it represents the magnetic core). The magnetic core includes three magnetic columns (magnetic columns 321A, 321B, and 321C respectively) and a magnetic yoke 322 connecting the three magnetic columns. The windings 311A, 311B, and 311C are wound around the magnetic columns 321A, 321B, and 321C respectively by different wires, and each winding extends two wire ends ( Figure 3a the wire ends of the winding 311B are not shown in it). The corresponding relationship between the winding and the magnetic column can be referred to Figure 3a and will not be elaborated here.

[0054] However,Figure 3a The integrated inductor 300 shown has a problem of coupling between three phases. As Figure 3b shown, it can be seen from the simulation by finite element software that when the winding 311A is energized (i.e., when an excitation is applied to the circuit of the phase where the winding 311A is located), a magnetic field is generated in the magnetic column 321A. Figure 3b In , the arrows on the winding 311 represent the current direction in the winding, and the dotted lines with arrows represent the magnetic induction lines in the magnetic core. The magnetic induction lines generated by the winding 311A enter the magnetic columns 321B and 321C via the magnetic yoke 322 respectively. It can be seen that the integrated inductor 300 will generate a large inter-phase flux coupling between the three windings.

[0055] The function of the integrated inductor 300 is mainly to suppress the ripple in each winding's corresponding circuit. Next, the influence of the inter-phase flux coupling on the function of the integrated inductor will be analyzed through the circuit simulation results. Without considering the inter-phase coupling, the current waveform output by one winding (such as the winding 311A) in the integrated inductor 300 is as Figure 3c shown; when considering the inter-phase coupling, the current waveform output by this winding (such as the winding 311A) in the integrated inductor 300 is as Figure 3d shown. Figure 3c And Figure 3d In , the vertical axis is the current intensity (I), the unit is ampere (A), and the unit of the horizontal axis time is second (s). Comparing Figure 3c and Figure 3d it can be seen that when there is no inter-phase flux coupling, the current ripple output by the winding of the integrated inductor 300 is small; when there is a strong inter-phase flux coupling in the integrated inductor 300, the superposition phenomenon of the current ripple output by its winding is obvious, the ripple increases significantly, it is difficult to suppress the ripple in the corresponding circuit, resulting in losses or even damage to the corresponding device.

[0056] In order to reduce the volume and weight of the inductor and reduce the inter-phase flux coupling in the integrated inductor, the present application provides an integrated inductor and a multi-phase power converter provided with the integrated inductor.

[0057] Next, the integrated inductor provided by the embodiments of the present application will be introduced.

[0058] The embodiments of the present application provide an integrated inductor, which includes a magnetic core and N windings. The magnetic core includes N - 1 first magnetic columns and N second magnetic columns. The N windings are correspondingly arranged on the N second magnetic columns. The magnetic permeability of the first magnetic column is greater than that of the second magnetic column, and N is a positive integer greater than 2.

[0059] The N - 1 first magnetic columns and the N second magnetic columns are all parallel to the first direction and are alternately arranged along the second direction perpendicular to the first direction, so that any two adjacent second magnetic columns among the N second magnetic columns are separated by one of the N - 1 first magnetic columns.

[0060] The magnetic core further includes a first magnetic yoke disposed at the first end of each of the N second magnetic posts and a second magnetic yoke disposed at the second end thereof. The first magnetic yoke and the second magnetic yoke are configured to transmit the magnetic induction lines generated by the windings in the second magnetic posts to the first magnetic posts. Wherein the first magnetic yoke and / or the second magnetic yoke are respectively bonded to the second magnetic posts.

[0061] Taking N = 3 as an example below, the integrated inductor provided by the embodiment of the present application will be specifically introduced in conjunction with the accompanying drawings. In actual use, the number of N can be determined according to the electronic device where the integrated inductor is located. For example, if the electronic device includes a four-phase circuit, then N can be determined to be 4, and the integrated inductor can be manufactured accordingly according to the embodiment solution of the present application to be disposed in the electronic device to suppress the ripples in each phase circuit of the electronic device.

[0062] Reference Figure 4a , the integrated inductor 400 provided by the embodiment of the present application includes a magnetic core ( Figure 4a in which the rectangle filled with black dots represents the magnetic core) and three windings (winding 411A, winding 411B, and winding 411C).

[0063] The magnetic core ( Figure 4a in which the rectangle filled with black dots represents the magnetic core) includes five magnetic posts, specifically two first magnetic posts (such as Figure 4a the first magnetic post 421A and the first magnetic post 421B in Figure 4a ) and three second magnetic posts (such as Figure 4a the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C in Figure 4a ). Among them, the magnetic permeability of the first magnetic posts is greater than that of the second magnetic posts. The first magnetic post 421A, the first magnetic post 421B, the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C are all parallel to the first direction ( Figure 4a in which the Z direction represents the first direction in Figure 4a ), and the two first magnetic posts and the three second magnetic posts are alternately arranged in a second direction perpendicular to the first direction ( Figure 4a in which the X direction represents the second direction in Figure 4a ), that is, any two adjacent second magnetic posts are separated by a first magnetic post. In the embodiment of the present application, the arrangement order among the first magnetic post 421A, the first magnetic post 421B, the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C is as shown in Figure 4a .

[0064] The parallelism of the five magnetic posts is conducive to simplifying the processing technology. Affected by process errors, it is not specified that the five magnetic posts have an absolute parallel relationship, as long as they are approximately parallel.

[0065] The windings 311A, 411B, and 411C are respectively disposed on the second magnetic posts 422A, 422B, and 422C. For details, please refer toFigure 4a The winding 311A, the winding 411B, and the winding 411C are respectively wound by separate wires, and each winding extends two wire ends ( Figure 4a the wire ends of the winding 411B are not shown in the figure).

[0066] The five magnetic posts (i.e., the first magnetic post 421A, the first magnetic post 421B, the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) all include two ends. For the convenience of description, the end of the five magnetic posts facing the first direction is called the first end, and the end of the five magnetic posts facing the opposite direction of the first direction is called the second end. In Figure 4a the figure, the opposite direction of the first direction is the opposite direction of the Z direction.

[0067] The magnetic core ( Figure 4a the rectangle filled with black dots in the figure represents the magnetic core) further includes a first magnetic yoke 423 provided at the first end of each second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) and a second magnetic yoke 424 provided at the second end.

[0068] The first magnetic yoke 423 can be provided at the first end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by bonding with the first end of the second magnetic post. The second magnetic yoke 424 can be provided at the second end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by other means. For example, the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) and the second magnetic yoke 424 can be obtained in a single one-piece forming process.

[0069] Alternatively, the second magnetic yoke 424 can be provided at the second end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by bonding with the second end of the second magnetic post. The first magnetic yoke 423 can be provided at the first end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by other means. For example, the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) and the first magnetic yoke 423 can be obtained in a single one-piece forming process.

[0070] Alternatively, the first magnetic yoke 423 can be provided at the first end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by bonding with the first end of the second magnetic post. The second magnetic yoke 424 can be provided at the second end of the second magnetic post (i.e., the second magnetic post 422A, the second magnetic post 422B, and the second magnetic post 422C) by bonding with the second end of the second magnetic post.

[0071] The magnetic permeability of the first magnetic column is greater than that of the second magnetic column. The magnetic permeabilities of the first yoke 423 and the second yoke 424 are greater than that of air. The first yoke 423 and the second yoke 424 are used to transmit the magnetic induction lines generated by the winding in the second magnetic column to the adjacent first magnetic column. The magnetic induction lines generated by any winding of the integrated inductor 400 in the corresponding second magnetic column are transmitted along the first yoke 423 and the second yoke 424 of the second magnetic column, and more magnetic induction lines enter the first magnetic column adjacent to the second magnetic column to form a closed curve, and fewer magnetic induction lines pass through other second magnetic columns, which is beneficial to reducing the inter-phase coupling in the integrated inductor 400 and is beneficial to suppressing the ripple in the circuit where it is located. The following combines Figure 4b and Figure 4c to introduce the magnetic field situation in the integrated inductor 400 by way of example.

[0072] Figure 4b is a schematic diagram of the equivalent magnetic circuit in the magnetic core ( Figure 4b in which the filled black rectangle represents the magnetic core) when the winding 411A is energized. When the winding 411A is energized, a magnetic field is generated in the second magnetic column 422A. In Figure 4b , the arrow on the winding 411A represents the current direction in the winding, and the dotted line with an arrow represents the magnetic induction lines in the magnetic core. The magnetic induction lines are used to describe the magnetic field generated by the winding 411A, and the magnetic induction lines are closed curves. As the path of the magnetic induction lines transmitted in the first yoke 423 and the second yoke 424 extends, the magnetic resistance of the path increases. Since the magnetic induction lines always follow the path with the minimum magnetic resistance (i.e., the maximum magnetic permeability), and since the magnetic permeability of the first magnetic column 421A is greater than that of the second magnetic column 422B, therefore, more of the magnetic induction lines generated by the winding 411A in the second magnetic column 422A are transmitted through the first magnetic column 421A to form a closed curve in the magnetic core, and fewer magnetic induction lines pass through the second magnetic columns 422B and 422C. Moreover, the greater the difference between the magnetic permeability of the first magnetic column 421A and that of the second magnetic column 422B, the greater the proportion of the magnetic induction lines in the second magnetic column 422A that will pass through the first magnetic column 421A.

[0073] Figure 4c is a schematic diagram of the equivalent magnetic circuit in the magnetic core ( Figure 4c in which the filled black rectangle represents the magnetic core) when the winding 411B is energized. When the winding 411B is energized, a magnetic field is generated in the second magnetic column 422B. In Figure 4bIn the figure, the direction of the current in the winding 411B is represented by the arrow on the winding 411B, and the magnetic induction lines in the magnetic core are represented by the dashed lines with arrows. The magnetic induction lines are used to describe the magnetic field generated by the winding 411B, and the magnetic induction lines are closed curves. As the path of the magnetic induction lines extending in the first yoke 423 and the second yoke 424 increases, the magnetic resistance of the path increases. Since the magnetic induction lines always follow the path with the minimum magnetic resistance (i.e., the maximum magnetic permeability), and since the magnetic permeability of the first magnetic posts 421A and 421B is greater than that of the second magnetic posts 422A and 422C, therefore, more of the magnetic induction lines generated by the winding 411B in the second magnetic post 422B are transmitted through the first magnetic posts 421A and 421B to form a closed curve in the magnetic core, and fewer magnetic induction lines pass through the second magnetic posts 422A and 422C. Moreover, the greater the difference in magnetic permeability between the first magnetic post 421A and the second magnetic post 422A, and the greater the difference in magnetic permeability between the first magnetic post 421B and the second magnetic post 422C, the greater the proportion of the magnetic induction lines in the second magnetic post 422B that pass through the first magnetic posts 421A and 421B.

[0074] In a possible implementation, the respective magnetic posts in the integrated inductor 400 are on the same plane, which is beneficial to reducing the volume of the integrated inductor 400 and increasing the power density of the integrated inductor 400.

[0075] Figure 4a The illustrated integrated inductor 400 takes the example that each of the second magnetic posts shares a first yoke 423 and a second yoke 424. Or rather, the first yoke 423 of each of the second magnetic posts is obtained in the same one - piece molding process, and the second yoke 424 of each of the second magnetic posts is obtained in the same one - piece molding process. This is beneficial to simplifying the processing technology of the integrated inductor 400 and reducing the processing cost.

[0076] Figure 4d For Figure 4a a possible bottom view of the illustrated integrated inductor 400, in combination with Figure 4a and Figure 4d in a possible implementation, the first ends of the respective first magnetic posts and second magnetic posts are adhesively bonded to the lower surface (i.e., the surface close to the magnetic posts) of the first yoke 423, and the second ends of the respective first magnetic posts and second magnetic posts are adhesively bonded to the upper surface (i.e., the surface close to the magnetic posts) of the second yoke 424, and there is a certain air gap between the two adhesively bonded parts.

[0077] In a possible implementation, the first ends of some or all of the first magnetic posts and second magnetic posts can be adhesively bonded to the side surface of the first yoke 423, and the second ends of some or all of the first magnetic posts and second magnetic posts can be adhesively bonded to the side surface of the second yoke 424.

[0078] Figure 4aOnly an exemplary implementation of the connection between the yoke and the magnetic posts is provided. The following will introduce other implementation manners in combination with Figures 4e to 4g to introduce other implementation manners.

[0079] In a possible implementation manner, each second magnetic post has a separate first yoke 423 and a separate second yoke 424. Moreover, the first yokes 423 of any two adjacent second magnetic posts are connected by the first magnetic post between these two second magnetic posts, and the second yokes 424 of any two adjacent second magnetic posts are connected by the first magnetic post between these two second magnetic posts. The two ends of each first magnetic post are flush with the first yoke 423 and the second yoke 424 respectively, which is beneficial to improving the tolerance of the manufacturing process of the integrated inductor 400 to process errors. Figure 4e The side view and bottom view of another possible structure of the integrated inductor 400 are shown. The so-called connection can refer to connection by means of bonding or other means, as long as the magnetic induction lines can pass through the connected components while reducing magnetic leakage. Refer to Figure 4e , the first yoke 423 of the second magnetic post 422A is connected to the first yoke 423 of the second magnetic post 422B through the first magnetic post 421A, and the first yoke 423 of the second magnetic post 422B is connected to the first yoke 423 of the second magnetic post 422C through the first magnetic post 421B; the second yoke 424 of the second magnetic post 422A is connected to the second yoke 424 of the second magnetic post 422B through the first magnetic post 421A, and the second yoke 424 of the second magnetic post 422B is connected to the second yoke 424 of the second magnetic post 422C through the first magnetic post 421B.

[0080] In a possible implementation manner, some adjacent second magnetic posts share a first yoke 423, and the first yokes 423 of some adjacent second magnetic posts are connected by the first magnetic post therebetween; some adjacent second magnetic posts share a second yoke 424, and the second yokes 424 of some adjacent second magnetic posts are connected by the first magnetic post therebetween. Figure 4f The side view, top view and bottom view of another possible structure of the integrated inductor 400 are shown. Refer to Figure 4f , the first yoke 423 of the second magnetic post 422A is connected to the first yoke 423 of the second magnetic post 422B through the first magnetic post 421A, and the second magnetic post 422B and the second magnetic post 422C share a first yoke 423; the second magnetic post 422A and the second magnetic post 422B share a second yoke 424, and the second yoke 424 of the second magnetic post 422B is connected to the second yoke 424 of the second magnetic post 422C through the first magnetic post 421B.

[0081] In a possible implementation, each second magnetic post has a separate first magnetic yoke 423, and the first magnetic yokes 423 of any two adjacent second magnetic posts are connected by a first magnetic post between the two second magnetic posts; each second magnetic post shares a second magnetic yoke 424. Figure 4g The side view, top view and bottom view showing another possible structure of the integrated inductor 400 are provided. Refer to Figure 4g , the first magnetic yoke 423 of the second magnetic post 422A is connected to the first magnetic yoke 423 of the second magnetic post 422B through the first magnetic post 421A, and the first magnetic yoke 423 of the second magnetic post 422B is connected to the first magnetic yoke 423 of the second magnetic post 422C through the first magnetic post 421B; the second magnetic post 422A, the second magnetic post 422B and the second magnetic post 422C share a second magnetic yoke 424.

[0082] Above, taking the integrated inductor including 3 windings as an example, the structure of the integrated inductor provided by the embodiments of the present application is introduced by way of example. Next, the materials in the integrated inductor provided by the embodiments of the present application are introduced by way of example.

[0083] In a possible implementation, the magnetic permeabilities of the materials of the second magnetic posts, the first magnetic yokes and the second magnetic yokes are close.

[0084] In a possible implementation, the second magnetic posts of the integrated inductor can be made of powder core materials or ferrite air gap composite materials.

[0085] Alternatively, in a possible implementation, the first magnetic yoke and / or the second magnetic yoke are selected to be made of the same material as the second magnetic posts.

[0086] In a possible implementation, the first magnetic yokes and the second magnetic yokes of the second magnetic posts can be made of powder core materials or ferrite air gap composite materials.

[0087] In a possible implementation, the first magnetic posts of the integrated inductor can be made of multi-layered strips with a relatively high magnetic permeability. For example, they can be made of amorphous strips or nanocrystalline strips. More specifically, they are generally made of multi-layered amorphous or nanocrystalline metal strips.

[0088] In a possible implementation, the plane of any layer of strip in the first magnetic post is parallel to the first direction.

[0089] Next, taking Figure 4b the first magnetic post 421A in

[0090] as an example, the structure of the first magnetic post is introduced. Taking the first magnetic post 421A including three layers of strips (strip 421A1, strip 421A2 and strip 421A3) as an example, and the planes of the three layers of strips are all parallel to the Y direction and the Z direction, that is, parallel to the plane Y-Z, Figure 5ashows Figure 4b a possible partial schematic diagram of Figure 4a showing specifically the first magnetic post 421A, the first yoke 423 and the second yoke 424 of the second magnetic post 422A in

[0091] The difference in the distribution of magnetic induction lines in different planes parallel to the plane X-Z in the integrated inductor 400 is very small. It can be considered that the distribution of magnetic induction lines in different planes parallel to the plane X-Z in the integrated inductor 400 is the same. Therefore Figure 5a only the magnetic induction lines (represented by dashed lines with arrows) in a plane parallel to the plane X-Z inside the first yoke 423 and the second yoke 424 are taken as an example.

[0092] Assume that the magnetic paths obtained when the magnetic induction line passes through the strips 421A1, 421A2 and 421A3 are magnetic path 1, magnetic path 2 and magnetic path 3 respectively, as shown by curves 1, 2, 3 in Figure 5a respectively. The longer the path that the magnetic path experiences in the first yoke 423, the greater the magnetic resistance of this magnetic path. Similarly, the longer the path that the magnetic path experiences in the second yoke 424, the greater the magnetic resistance of this magnetic path. Therefore, the magnetic resistance of magnetic path 3 is greater than that of magnetic path 2, and the magnetic resistance of magnetic path 2 is greater than that of magnetic path 1. As shown in Figure 5a , assume that in the first yoke 423, magnetic path 3 passes through a magnetic resistance Rm2 more than magnetic path 2, and magnetic path 2 passes through a magnetic resistance Rm1 more than magnetic path 1; in the second yoke 424, magnetic path 3 passes through a magnetic resistance Rm4 more than magnetic path 2, and magnetic path 2 passes through a magnetic resistance Rm3 more than magnetic path 1. Since the magnetic induction line always takes the path with the smallest magnetic resistance (i.e., the largest magnetic permeability), the magnetic induction lines in the first yoke 423 and the second yoke 424 more choose magnetic path 1. That is to say, the distribution of the magnetic induction lines generated by the winding 411A in the strips 421A1, 421A2 and 421A3 is uneven, the equivalent magnetic flux area of the first magnetic post 421A is reduced, and the first magnetic post 421A is more likely to have magnetic flux saturation.

[0093] To solve the above problems, in a possible implementation manner, the plane of any layer of strip in the first magnetic post is parallel to the first direction and parallel to the second direction.

[0094] Still taking the first magnetic post 421A including three layers of strips (strip 421A1, strip 421A2 and strip 421A3) as an example, and the planes of the three layers of strips are all parallel to the X direction and the Z direction, that is, parallel to the plane X-Z, Figure 5b shows Figure 4b another possible partial schematic diagram, specifically showing Figure 4a the first magnetic post 421A, the first yoke 423 and the second yoke 424 of the second magnetic post 422A in

[0095] Assume that the magnetic flux paths obtained when the magnetic induction lines in the first yoke 423 and the second yoke 424 pass through the strip 421A1, the strip 421A2, and the strip 421A3 are the magnetic flux path 1, the magnetic flux path 2, and the magnetic flux path 3 respectively, as shown by curves 1, 2, and 3 in Figure 5a . The distribution differences of the magnetic induction lines in the integrated inductor 400 in different planes parallel to the plane X-Z are very small. It can be considered that the distributions of the magnetic induction lines in the integrated inductor 400 in different planes parallel to the plane X-Z are the same. Moreover, the magnetic resistances of the magnetic flux path 1, the magnetic flux path 2, and the magnetic flux path 3 are the same. That is to say, the magnetic induction lines generated by the winding 411A are evenly distributed in the strip 421A1, the strip 421A2, and the strip 421A3. The equivalent magnetic flux area of the first magnetic column 421A is larger, and it is not easy for the first magnetic column 421A to appear magnetic flux saturation.

[0096] In a possible implementation manner, the inductance balance of the three windings can be achieved by adjusting the number of turns of the winding, or adjusting the air gap size between the corresponding second magnetic column of the winding and the first yoke and / or the second yoke, or adjusting the cross-sectional area of the second magnetic column.

[0097] By comparing Figure 4b and Figure 4c in the equivalent magnetic flux paths, it can be seen that if the magnetic induction lines entering other second magnetic columns are not considered, since the windings 411A and 411C are only adjacent to one first magnetic column (the first magnetic column 421A and the first magnetic column 421B respectively), therefore, all the magnetic induction lines generated by the windings 411A and 411C pass through a single first magnetic column; while the winding 411B is adjacent to two first magnetic columns (the first magnetic column 421A and the first magnetic column 421B) at the same time. Therefore, part of the magnetic induction lines generated by the winding 411B pass through the first magnetic column 421A, and the other part of the magnetic induction lines pass through the first magnetic column 421B.

[0098] The magnetic flux paths through which the magnetic induction lines generated by the windings 411A, 411B, and 411C pass are respectively called the magnetic flux path A, the magnetic flux path B, and the magnetic flux path C. When the cross-sectional areas of the three second magnetic columns are equal, the cross-sectional area of the magnetic flux path B is larger than the cross-sectional areas of the magnetic flux path A and the magnetic flux path C. In order to balance the inductance of the three windings, in a possible implementation manner, the number of turns of the middle winding in the integrated inductor is less than that of the other windings. The middle winding is arranged on the second magnetic column between two of the N - 1 first magnetic columns, and the other windings are the other windings except the middle winding among the N windings.

[0099] In a possible implementation manner, the cross-sectional area of the middle magnetic column in the integrated inductor on the plane perpendicular to the first direction is smaller than the cross-sectional areas of the other magnetic columns on the plane perpendicular to the first direction. The middle magnetic column is the second magnetic column between two of the N - 1 first magnetic columns, and the other magnetic columns are the other second magnetic columns except the middle magnetic column among the N second magnetic columns.

[0100] In order to increase the heat dissipation area of each winding in the integrated inductor, in a possible implementation, the cross-sectional area of the second magnetic column of the integrated inductor in a plane perpendicular to the first direction is elliptical or rectangular.

[0101] The embodiment of the present application further provides a power converter, which is a multi-phase power converter. The integrated inductor in any embodiment of the present application is used as a filter inductor to suppress the ripple in each phase of alternating current. Specifically, the power converter includes N switching bridge arms and the integrated inductor in any embodiment of the present application. The N switching bridge arms correspond to the N windings in the integrated inductor one by one. Moreover, the midpoint of each switching bridge arm among the N switching bridge arms is connected to the AC input end or the AC output end of the power converter through a corresponding winding.

[0102] For example, if the power converter is a rectifier, then the midpoint of each switching bridge arm is connected to a corresponding AC input end through a corresponding winding; if the power converter is an inverter, then the midpoint of each switching bridge arm is connected to a corresponding AC output end through a corresponding winding.

[0103] Exemplarily, the power converter may be Figure 1 the three-phase inverter 100 as shown. In the three-phase inverter 100, there is an integrated inductor 400 as shown. Specifically, Figure 4a the first-stage inductors L1-1, L1-2, and L1-3 in Figure 1 correspond to the three windings in the integrated inductor 400, namely, winding 411A, winding 411B, and winding 411C. The midpoint a1 of the switching bridge arm 1101 of the three-phase inverter 100 is connected to the AC output end a3 through L1-1 (i.e., winding 411A), C1, and L1-2. The winding 411A is used to suppress the ripple in the alternating current output from the midpoint a1; the midpoint b1 of the switching bridge arm 1102 is connected to the AC output end b3 through L2-1 (i.e., winding 411B), C2, and L2-2. The winding 411B is used to suppress the ripple in the alternating current output from the midpoint b1; the midpoint c1 of the switching bridge arm 1103 is connected to the AC output end c3 through L3-1 (i.e., winding 411C), C3, and L3-2. The winding 411C is used to suppress the ripple in the alternating current output from the midpoint c1.

[0104] The above has introduced the technical solution provided by this application in detail. Specific examples are used in this application to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. An integrated inductor, characterized in that, it includes a magnetic core and N windings. The magnetic core includes N - 1 first magnetic posts and N second magnetic posts. The N windings are respectively arranged on the N second magnetic posts. The magnetic permeability of the first magnetic posts is greater than that of the second magnetic posts, and N is a positive integer greater than 2; the N - 1 first magnetic posts and the N second magnetic posts are all parallel to a first direction and are alternately arranged along a second direction perpendicular to the first direction, so that any two adjacent second magnetic posts among the N second magnetic posts are separated by one of the N - 1 first magnetic posts; the magnetic core further includes a first magnetic yoke provided at the first end of each of the N second magnetic posts and a second magnetic yoke provided at the second end, wherein the first magnetic yoke and / or the second magnetic yoke are respectively bonded to the second magnetic posts; the material of the second magnetic posts is the same as that of the first magnetic yoke and / or the second magnetic yoke.

2. The integrated inductor according to claim 1, characterized in that, the N second magnetic posts share a first magnetic yoke and / or a second magnetic yoke, and the first magnetic yoke and / or the second magnetic yoke are respectively integrally formed.

3. The integrated inductor according to claim 2, characterized in that, the N - 1 first magnetic posts are arranged between the first magnetic yoke and the second magnetic yoke.

4. The integrated inductor according to claim 1, characterized in that, each of the N second magnetic posts corresponds to a first magnetic yoke and a second magnetic yoke respectively, and both ends of the N - 1 first magnetic posts are flush with the first magnetic yoke and the second magnetic yoke respectively.

5. The integrated inductor according to any one of claims 1 to 4, characterized in that, each of the N - 1 first magnetic posts is made of a multi - layer strip.

6. The integrated inductor according to claim 5, characterized in that, the plane of any one layer of the multi - layer strip is parallel to the first direction and the second direction.

7. The integrated inductor according to claim 5, characterized in that, the multi - layer strip is an amorphous strip or a nanocrystalline strip.

8. The integrated inductor according to claim 6, characterized in that, the multi - layer strip is an amorphous strip or a nanocrystalline strip.

9. The integrated inductor according to any one of claims 1 to 4, 6 to 8, characterized in that, the number of turns of the middle winding among the N windings is less than that of the other windings. The middle winding is arranged on the second magnetic post between any two of the N - 1 first magnetic posts, and the other windings are the other windings among the N windings except the middle winding.

10. The integrated inductor according to claim 5, characterized in that, the number of turns of the middle winding among the N windings is less than that of the other windings. The middle winding is arranged on the second magnetic post between any two of the N - 1 first magnetic posts, and the other windings are the other windings among the N windings except the middle winding.

11. The integrated inductor according to any one of claims 1 to 4, 6 to 8, characterized in that, The cross-sectional area of the middle magnetic column among the N second magnetic columns on a first plane perpendicular to the first direction is smaller than the cross-sectional areas of the other second magnetic columns on the first plane. The middle magnetic column is a second magnetic column located between any two of the N-1 first magnetic columns, and the other second magnetic columns are the other second magnetic columns among the N second magnetic columns excluding the middle magnetic column.

12. The integrated inductor according to claim 5, wherein, The cross-sectional area of the middle magnetic column among the N second magnetic columns on a first plane perpendicular to the first direction is smaller than the cross-sectional areas of the other second magnetic columns on the first plane. The middle magnetic column is a second magnetic column located between any two of the N-1 first magnetic columns, and the other second magnetic columns are the other second magnetic columns among the N second magnetic columns excluding the middle magnetic column.

13. The integrated inductor according to any one of claims 1 to 4, 6 to 8, wherein the material of the first magnetic yoke and / or the second magnetic yoke and the second magnetic column is a powder core material or a ferrite air gap composite material.

14. The integrated inductor according to claim 5, wherein the material selected for the first magnetic yoke and / or the second magnetic yoke and the second magnetic column is a powder core material or a ferrite air gap composite material.

15. A power converter, wherein, comprising N switching bridge arms and an integrated inductor according to any one of claims 1 to 14. The N switching bridge arms correspond one-to-one to the N windings in the integrated inductor, and the midpoint of each switching bridge arm among the N switching bridge arms is connected to the AC input terminal or the AC output terminal of the power converter through a corresponding winding.

Images