CN211957324U

CN211957324U - Integrated inductor and power converter

Info

Publication number: CN211957324U
Application number: CN202020161438.9U
Authority: CN
Inventors: 石磊; 唐云宇; 王朝辉
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2020-02-11
Filing date: 2020-02-11
Publication date: 2020-11-17
Anticipated expiration: 2030-02-11

Abstract

The embodiment of the application discloses an integrated inductor, which is used for solving the problems of overlarge cost, size and weight of an inductor structure in the conventional multiphase power converter. The magnetic core in the integrated inductor comprises N-1 first magnetic columns and N second magnetic columns, N windings are correspondingly arranged on the N second magnetic columns one by one, the magnetic permeability of the first magnetic columns is greater than that of the second magnetic columns, and N is a positive integer greater than 2; the N-1 first magnetic columns and the N second magnetic columns are parallel to the first direction and are alternately arranged along a second direction perpendicular to the first direction, so that any two adjacent second magnetic columns in the N second magnetic columns are spaced by one first magnetic column in the N-1 first magnetic columns; the magnetic core further comprises a first magnetic yoke arranged at the first end and a second magnetic yoke arranged at the second end of each of the N second magnetic columns, wherein the first magnetic yoke and/or the second magnetic yoke are/is respectively bonded with the second magnetic columns.

Description

Integrated inductor and power converter

Technical Field

The present application relates to the field of inductor technology, and more particularly, to an integrated inductor and power converter.

Background

In general, there is a relatively serious ripple in the multiphase power converter, and the excessive ripple may cause loss and even damage to the electric equipment. In order to protect the power converter, the ripple in the circuit needs to be suppressed.

In the prior art, an inductance structure is arranged in each phase circuit of a power converter, and the inductance structure includes a winding and a magnetic core, where the magnetic core includes two magnetic poles and a magnetic yoke connecting the two magnetic poles, and the winding is formed by winding a conducting wire around the two magnetic poles.

As the power class of multiphase power converters is increasing, the cost, size, and weight of the inductor structure for suppressing ripples in each phase circuit of the multiphase power converters are increasing significantly, increasing the cost of the power converters and reducing the power density thereof.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides an integrated inductor, which is used for solving the problems of overlarge cost, size and weight of an inductor structure in the conventional multiphase power converter, so that the cost of the power converter is reduced, and the power density of the power converter is improved.

In order to solve the above technical problem, an embodiment of the present application provides the following technical solutions:

in a first aspect, an embodiment of the present application provides an integrated inductor, which includes a magnetic core and N conductive windings (windings for short), where each winding is wound by a conducting wire and extends out of two wire ends. The magnetic core comprises N-1 first magnetic columns and N second magnetic columns, the N windings are correspondingly arranged on the N second magnetic columns one by one, the magnetic permeability of the first magnetic columns is greater than that of the second magnetic columns, and N is a positive integer greater than 2; the N-1 first magnetic columns and the N second magnetic columns are parallel to a first direction, and the N-1 first magnetic columns and the N second magnetic columns are alternately arranged along a second direction perpendicular to the first direction, so that any two adjacent second magnetic columns in the N second magnetic columns are separated by one first magnetic column in the N-1 first magnetic columns; the magnetic core further includes a first yoke disposed at a first end and a second yoke disposed at a second end of each of the N second legs. The first magnetic yoke and the second magnetic yoke are used for transmitting the magnetic induction lines generated in the second magnetic column by the winding into the first magnetic column.

The first magnetic yoke may be disposed at the first end of the second magnetic pillar by being bonded to the first end of the second magnetic pillar, and the second magnetic yoke may be disposed at the second end of the second magnetic pillar by other means, for example, the second magnetic pillar and the second magnetic yoke may be obtained in one-step integral molding process.

Alternatively, the second magnetic yoke may be disposed at the second end of the second magnetic pillar by being bonded to the second end of the second magnetic pillar, and the first magnetic yoke may be disposed at the first end of the second magnetic pillar by other means, for example, the second magnetic pillar and the first magnetic yoke may be obtained in a one-step integral molding process.

Or the first magnetic yoke can be arranged at the first end of the second magnetic column in a bonding mode with the first end of the second magnetic column, and the second magnetic yoke can be arranged at the second end of the second magnetic column in a bonding mode with the second end of the second magnetic column.

The inductor structure in the multiphase circuit in the power converter is integrated, so that the cost, the volume and the weight of the inductor structure in the multiphase power converter are reduced, the cost of the power converter is reduced, and the power density of the power converter is improved.

In a possible implementation manner, the N second magnetic pillars may share a first magnetic yoke, and the first magnetic yoke may be a molded one.

Alternatively, in a possible implementation manner, the N second magnetic pillars may share one second magnetic yoke, and the second magnetic yoke may be integrally formed.

Alternatively, in a possible implementation manner, the N second magnetic pillars may share a first magnetic yoke, which may be a molded one, and the N second magnetic pillars share a second magnetic yoke, which is an integrally molded one.

Or, in a possible implementation manner, M adjacent second magnetic columns in the N second magnetic columns share one first magnetic yoke, and the other N-M second magnetic columns respectively correspond to one first magnetic yoke. Or, in a possible implementation manner, M adjacent second magnetic columns in the N second magnetic columns share one second magnetic yoke, and the other N-M second magnetic columns respectively correspond to one second magnetic yoke. M is a positive integer greater than 1 and less than N.

Based on the fact that N second magnetic columns share one first magnetic yoke and one second magnetic yoke, in one possible implementation, N-1 first magnetic columns may be disposed between the first magnetic yoke and the second magnetic yoke. In one possible implementation manner, the N-1 first magnetic columns can be arranged between the first magnetic yoke and the second magnetic yoke in an adhesion mode.

In a possible implementation manner, each of the N second magnetic pillars may correspond to a first magnetic yoke and a second magnetic yoke, respectively, where two ends of the N-1 first magnetic pillars are flush with the first magnetic yoke and the second magnetic yoke, respectively.

In one possible implementation, each of the N-1 first magnetic pillars is made of a multi-layered strip material.

In a possible implementation manner, the plane of any one of the multiple layers of tapes is parallel to the first direction and the second direction.

In one possible implementation, the multilayer strip is an amorphous strip or a nanocrystalline strip.

In a possible implementation manner, the number of turns of a middle winding in the N windings is smaller than the number of turns of other windings, the middle winding is disposed on a second magnetic pillar located between any two first magnetic pillars in the N-1 first magnetic pillars, and the other windings are other windings than the middle winding in the N windings.

In a possible implementation manner, a cross-sectional area of a middle magnetic column in the N second magnetic columns on a first plane perpendicular to the first direction is smaller than cross-sectional areas of other second magnetic columns on the first plane, the middle magnetic column is a second magnetic column located between any two first magnetic columns in the N-1 first magnetic columns, and the other second magnetic columns are other second magnetic columns in the N second magnetic columns except for the middle magnetic column.

In one possible implementation, the magnetic permeability of the material of the second magnetic pillar, the magnetic permeability of the material of the first magnetic yoke, and the magnetic permeability of the material of the second magnetic yoke are close.

Alternatively, in a possible implementation manner, the first magnetic yoke is made of the same material (referred to as a first material) as the second magnetic pillar, that is, the material of the first magnetic yoke is the same as that of the second magnetic pillar; alternatively, in a possible implementation manner, the second magnetic yoke is made of the same material (called as the first material) as the second magnetic pillar, that is, the material of the second magnetic yoke is the same as that of the second magnetic pillar; alternatively, in a possible implementation, the first magnetic yoke and the second magnetic yoke are made of the same material as the second magnetic pillar (referred to as the first material), that is, the material of the first magnetic yoke, the material of the second magnetic yoke, and the material of the second magnetic pillar are all the same. In one possible implementation, the first material is a powder core material or a ferrite air gap composite material.

In a second aspect, an embodiment of the present application provides a power converter, which includes N switching legs and an integrated inductor as described in the first aspect or any one of the possible implementations of the first aspect, where the integrated inductor includes N windings, the N switching legs correspond to the N windings in the integrated inductor in a one-to-one manner, and a midpoint of each of the N switching legs is connected to an ac input end or an ac output end of the power converter through one of the N windings corresponding to the switching leg.

Drawings

Fig. 1 is a schematic diagram of a structure of a conventional three-phase inverter;

FIG. 2a is a schematic diagram of a first stage inductor in a prior art three-phase inverter;

FIG. 2b is a schematic diagram of an equivalent magnetic circuit in the core when the windings in the first stage inductor of FIG. 2a are energized;

FIG. 3a is a schematic diagram of a prior art integrated inductor;

FIG. 3b is a schematic diagram of an equivalent magnetic circuit in the core when winding 311A in FIG. 3a is energized;

FIG. 3c is a schematic diagram of the current waveform output by the winding of the integrated inductor without regard to phase-to-phase coupling;

FIG. 3d is a schematic diagram of the current waveform output by the winding of the integrated inductor considering the inter-phase coupling;

fig. 4a is a schematic diagram of an embodiment of an integrated inductor provided in the present application;

FIG. 4b is a schematic diagram of an equivalent magnetic circuit in the core when the winding 411A in FIG. 4a is energized;

FIG. 4c is a schematic diagram of an equivalent magnetic circuit in the core when the winding 411B in FIG. 4a is energized;

FIG. 4d is a bottom view of one possible integrated inductor of FIG. 4 a;

fig. 4e is a schematic diagram of another embodiment of the integrated inductor provided in the present application;

fig. 4f is a schematic diagram of another embodiment of the integrated inductor provided in the present application;

fig. 4g is a schematic diagram of another embodiment of the integrated inductor provided in the present application;

FIG. 5a is a partial schematic view of one possible embodiment of FIG. 4 b;

fig. 5b is another possible partial schematic view of fig. 4 b.

Detailed Description

A multiphase circuit (three or more phases) generally includes a plurality of ac inputs, or a plurality of ac outputs, or a plurality of ac inputs and a plurality of ac outputs, so as to input or output ac with the same frequency and different phases. Multiphase power converters are generally of 3 basic types, namely multiphase rectifiers, multiphase inverters and multiphase cycloconverters. The multi-phase rectifier is used for converting multi-phase alternating current input by the multiple alternating current input ends into direct current; the multi-phase inverter is used for converting the direct current into multi-phase alternating current and outputting the multi-phase alternating current through a plurality of alternating current output ends; the multiphase cycloconverter is used for converting multiphase alternating current with one frequency input by a plurality of alternating current input ends into multiphase alternating current with another frequency (namely alternating current-alternating current conversion), or converting multiphase alternating current with fixed voltage (or power) into multiphase alternating current with another voltage (or power) (namely alternating current voltage regulation and alternating current power regulation) and outputting the multiphase alternating current with another voltage (or power) through a plurality of alternating current output ends.

A multiphase power converter generally includes a plurality of switching legs connected in parallel, and midpoints of the plurality of switching legs are respectively connected to a plurality of ac input terminals or a plurality of ac output terminals of the multiphase power converter.

Ripple is a high frequency ac component superimposed on a dc or ac steady amount. The ripple has a complex component, and its form is generally a harmonic wave with a frequency higher than the power frequency (50 Hz in china) similar to a sine wave, and the other is a pulse wave with a narrow width.

The excessive ripple causes loss and even damage to the electric equipment. In order to suppress the ripple in the multiphase power converter, a plurality of inductors are generally disposed in the multiphase power converter for suppressing the ripple in the alternating current of each phase. Specifically, the midpoint of one switching leg is connected to the output of the multiphase power converter through the inductor.

The power of a multiphase power converter is generally large and, therefore, the inductor is generally a power inductor. Generally, an inductor in an electronic circuit can only pass a small current and bear a low voltage; the power inductor in the power converter is generally wound by thick wires, can bear tens, hundreds, thousands or even tens of thousands of amperes of alternating current, and mainly plays a role in filtering and oscillating in a circuit.

In the following, a power inductor for suppressing ripples of ac power of each phase in a multi-phase power electronic device will be described by taking a three-phase inverter as an example.

Fig. 1 is a schematic structural diagram of a three-phase inverter, and as shown in fig. 1, an inverter 100 includes an inverter unit 110 and a filter unit 120, an input end (denoted by "in fig. 1) of the inverter unit 110 is used for connecting a direct current power supply (denoted by" Vin "in fig. 1), the inverter unit 110 includes three parallel switch bridge arms (corresponding to circuits in a dashed line box 1101, a dashed line box 1102 and a dashed line box 1103 in fig. 1 respectively), the three parallel switch bridge arms are used for converting input direct current into alternating current with the same frequency and different phases respectively, and outputting corresponding alternating current through respective midpoints (denoted by" a1 "," b1 "and" c1 "in fig. 1 respectively); the filter unit 120 includes three inductor-capacitor-inductor (LCL for short), specifically, L1-1, C1, and L1-2 constitute an LCL, L2-1, C2, and L2-2 constitute an LCL, and L3-1, C3, and L3-2 constitute an LCL. The input ends of three LCL structures (in fig. 1, three input ends are represented by "a 2", "b 2", and "c 2", respectively) are respectively connected to three output ends of the inverter unit 110 (i.e., middle points of three switching legs), each LCL structure is configured to filter an input path of alternating current, and output the filtered alternating current through the output ends of the LCL structure (in fig. 1, output ends of three LCL structures, i.e., three alternating current output ends of a three-phase inverter are represented by "a 3", "b 3", and "c 3"), for example, the filtered alternating current is output to a power grid.

Each LCL structure of the filtering unit 120 includes two inductances L, and the inductance closer to the input terminal ("a 2" or "b 2" or "c 2") is referred to as a first-stage inductance, and each of L1-1, L2-1 and L3-1 in fig. 1 is a first-stage inductance; the inductance closer to the output ("a 3" or "b 3" or "c 3") is referred to as the second stage inductance, and L1-2, L2-2 and L3-2 in fig. 1 are all second stage inductances. The first-stage inductor is mainly used for suppressing ripples in the circuit.

Each first-stage inductor of the conventional three-phase inverter employs an inductor structure 200 shown in fig. 2a, and the inductor structure 200 includes a winding 210 and a magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 2 a). The magnetic core comprises two legs 221 and a yoke 222 connecting the two legs, the winding 210 is wound around the two legs 221 by a wire, the winding 210 extends from two ends, and 210a and 210b represent two ends of the winding 210 in fig. 2 a.

Fig. 2b is a schematic diagram of an equivalent magnetic circuit in the core when winding 210 is energized. When winding 210 is energized, a magnetic field is generated in magnetic pillar 221. In fig. 2b, the arrows on winding 210 represent the direction of current flow in the winding, and the dotted lines with arrows represent the magnetic induction lines in the core. The magnetic induction lines are used to describe the magnetic field generated by the winding 210, and the magnetic induction lines are closed curves and always take the path with the smallest magnetic resistance (i.e. the largest magnetic permeability). Since the magnetic permeability of the yoke 222 is greater than that of air, the magnetic induction lines generated in the magnetic pole 221 by the winding 210 are transmitted along the yoke 222, forming a closed curve in the core.

As the power level of a three-phase inverter is increased, the cost, volume and weight of the first-stage inductor (as shown in fig. 2 a) in each phase circuit of the three-phase inverter are increased significantly, which increases the cost of the three-phase inverter and reduces the power density of the three-phase inverter.

To reduce costs, some studies have proposed using an integrated inductor 300 as shown in fig. 3a to provide three first stage inductors simultaneously for a three-phase inverter. As shown in fig. 3a, the integrated inductor 300 includes three windings (winding 311A, winding 311B, and winding 311C, respectively) and a magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 3 a). The magnetic core includes three magnetic poles (magnetic pole 321A, magnetic pole 321B, and magnetic pole 321C, respectively) and a yoke 322 connecting the three magnetic poles. Winding 311A, winding 311B, and winding 311C are respectively formed by winding different wires around leg 321A, leg 321B, and leg 321C, each of which extends beyond two terminals (the terminal of winding 311B is not shown in fig. 3 a). The corresponding relationship between the windings and the magnetic pillars can be referred to fig. 3a, and is not described herein.

However, the integrated inductor 300 shown in fig. 3a has a problem of coupling between three phases. As shown in fig. 3b, it can be seen from the finite element software simulation that when the winding 311A is energized (i.e. when excitation is applied to the one-phase circuit in which the winding 311A is located), a magnetic field is generated in the magnetic pillar 321A. The arrows on the winding 311 in fig. 3b represent the direction of the current in the winding, and the dashed lines with arrows represent the magnetic induction lines in the core. The magnetic induction lines generated by the winding 311A enter the magnetic pillar 321B and the magnetic pillar 321C through the magnetic yoke 322, respectively, and it can be seen that the integrated inductor 300 generates a large interphase magnetic flux coupling between the three windings.

The function of the integrated inductor 300 is mainly to suppress ripples in the circuit in which each winding is located, and the influence of inter-phase flux coupling on the function of the integrated inductor is analyzed through the circuit simulation result. The waveform of the current output by one winding (e.g., winding 311A) in the integrated inductor 300 without considering the phase-to-phase coupling is shown in fig. 3 c; the waveform of the current output by the winding (e.g., winding 311A) in the integrated inductor 300 is shown in fig. 3d, considering the coupling between phases. In fig. 3c and 3d, the ordinate is the current intensity (I) in amperes (a) and the abscissa is the time in seconds(s). Comparing fig. 3c and 3d, it can be seen that when there is no interphase flux coupling, the current ripple of the winding output of the integrated inductor 300 is small; when strong interphase magnetic flux coupling exists in the integrated inductor 300, the current ripple superposition phenomenon output by the winding is obvious, the ripple is obviously increased, and the ripple in the circuit is difficult to inhibit, so that the loss and even damage of the device are caused.

In order to reduce the size and weight of the inductor and reduce the coupling of magnetic flux between phases in the integrated inductor, the application provides the integrated inductor and the multiphase power converter provided with the integrated inductor.

The integrated inductor provided by the embodiment of the present application is described below.

The embodiment of the application provides an integrated inductor, this integrated inductor includes magnetic core and N windings, and the magnetic core includes N-1 first magnetism post and N second magnetism post, and the setting of N windings one-to-one is on N second magnetism posts, and the magnetic permeability of first magnetism post is greater than the magnetic permeability of second magnetism post, and N is for being greater than 2 positive integer.

The N-1 first magnetic columns and the N second magnetic columns are parallel to the first direction and are alternately arranged along a second direction perpendicular to the first direction, so that any two adjacent second magnetic columns in the N second magnetic columns are spaced by one first magnetic column in the N-1 first magnetic columns.

The magnetic core further comprises a first magnetic yoke arranged at the first end and a second magnetic yoke arranged at the second end of each of the N second magnetic columns, and the first magnetic yoke and the second magnetic yoke are used for transmitting magnetic induction lines generated in the second magnetic columns by the windings into the first magnetic column. And the first magnetic yoke and/or the second magnetic yoke are/is respectively bonded with the second magnetic column.

The integrated inductor provided by the embodiments of the present application is specifically described below with reference to the accompanying drawings, taking N-3 as an example. In practical use, the number of N may be determined according to an electronic device in which the integrated inductor is located, for example, if the electronic device includes a four-phase circuit, N may be determined to be 4, and the integrated inductor is manufactured according to the embodiment of the present application, so as to be disposed in the electronic device and suppress ripples in each phase circuit in the electronic device.

Referring to fig. 4a, an integrated inductor 400 provided by the embodiment of the present application includes a magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 4 a) and 3 windings (winding 411A, winding 411B, and winding 411C).

The magnetic core (the rectangle filled with black dots in fig. 4a represents the magnetic core) includes 5 magnetic pillars, specifically, 2 first magnetic pillars (e.g., the first magnetic pillar 421A and the first magnetic pillar 421B in fig. 4 a) and 3 second magnetic pillars (e.g., the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C in fig. 4 a), wherein the magnetic permeability of the first magnetic pillar is greater than that of the second magnetic pillar, the first magnetic pillar 421A, the first magnetic pillar 421B, the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C are all parallel to the first direction (the Z direction in fig. 4a represents the first direction), and the 2 first magnetic pillars are alternately arranged with the 3 second magnetic pillars in a second direction perpendicular to the first direction (the X direction in fig. 4a represents the second direction), that any two adjacent magnetic pillars are spaced apart by one first magnetic pillar. In the embodiment of the present application, the first magnetic pillar 421A, the first magnetic pillar 421B, the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C are arranged in the order shown in fig. 4 a.

The 5 magnetic columns are parallel to each other, so that the processing technology is simplified. Under the influence of process errors, the 5 magnetic columns are not limited to have an absolute parallel relation, and only need to be approximately parallel.

The

windings

311A, 411B, and 411C are disposed on the second

magnetic pillar

422A, 422B, and 422C in a one-to-one correspondence, please refer to fig. 4a specifically. Winding 311A, winding 411B, and winding 411C are each wound from separate wires, each of which extends over two wire ends (the wire end of winding 411B is not shown in fig. 4 a).

Each of the 5 magnetic pillars (i.e., the first magnetic pillar 421A, the first magnetic pillar 421B, the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C) includes two ends, and for convenience of description, one end of the 5 magnetic pillars facing the first direction is referred to as a first end, and one end of the 5 magnetic pillars facing the opposite direction of the first direction is referred to as a second end. In fig. 4a, the opposite direction to the first direction is the opposite direction to the Z direction.

The magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 4 a) further includes a first yoke 423 disposed at a first end and a second yoke 424 disposed at a second end of each of the second magnetic pillars, i.e., (second magnetic pillar 422A, second magnetic pillar 422B, and second magnetic pillar 422C).

The first yoke 423 may be disposed at a first end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)) by being bonded to a first end of the second magnetic pillar, and the second yoke 424 may be disposed at a second end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)) by other means, for example, the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)) and the second yoke 424 may be obtained in one-piece molding.

Alternatively, the second yoke 424 may be disposed at the second end of the second magnetic pillar by being bonded to the second end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)), and the first yoke 423 may be disposed at the first end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)) by other means, for example, the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)) and the first yoke 423 may be obtained in one-piece molding.

Alternatively, the first yoke 423 may be disposed at a first end of the second magnetic pillar by being bonded to a first end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)), and the second yoke 424 may be disposed at a second end of the second magnetic pillar by being bonded to a second end of the second magnetic pillar (i.e., (the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C)).

The magnetic permeability of the first magnetic pole is greater than that of the second magnetic pole, the magnetic permeability of the first magnetic yoke 423 and the second magnetic yoke 424 is greater than that of air, and the first magnetic yoke 423 and the second magnetic yoke 424 are used for transmitting magnetic induction lines generated in the second magnetic pole by the winding to the adjacent first magnetic pole. Magnetic induction lines generated in the corresponding second magnetic columns by any winding of the integrated inductor 400 are transmitted along the first magnetic yokes 423 and the second magnetic yokes 424 of the second magnetic columns, more magnetic induction lines enter the first magnetic columns adjacent to the second magnetic columns to form a closed curve, and less magnetic induction lines pass through other second magnetic columns, so that interphase coupling in the integrated inductor 400 is reduced, and the suppression of ripples in a circuit is facilitated. The magnetic field situation in the integrated inductor 400 is described below by way of example with reference to fig. 4b and 4 c.

Fig. 4b is a schematic diagram of an equivalent magnetic circuit in the magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 4 b) when the winding 411A is energized. When the winding 411A is energized, a magnetic field is generated in the second magnetic pillar 422A. In fig. 4b, the arrows on winding 411A represent the direction of current flow in the winding, and the dashed lines with arrows represent the magnetic induction lines in the core. The magnetic induction lines are used for describing the magnetic field generated by the winding 411A, and the magnetic induction lines are closed curves. As the path along which the magnetic induction lines travel in the first and

second yokes

423 and 424 is lengthened, the magnetic resistance of the path increases, since the magnetic induction lines always take the path with the smallest magnetic resistance (i.e., the largest magnetic permeability), and since the magnetic permeability of the first magnetic pillar 421A is greater than that of the second magnetic pillar 422B, more magnetic induction lines generated in the second magnetic pillar 422A by the winding 411A travel through the first magnetic pillar 421A, a closed curve is formed in the magnetic core, and less magnetic induction lines travel through the second

magnetic pillars

422B and 422C. Also, the greater the difference between the permeability of the first magnetic pillar 421A and the permeability of the second magnetic pillar 422B, the greater the proportion of the magnetic induction lines in the second magnetic pillar 422A will pass through the first magnetic pillar 421A.

Fig. 4c is a schematic diagram of an equivalent magnetic circuit in the magnetic core (the magnetic core is represented by a rectangle filled with black dots in fig. 4 c) when the winding 411B is energized. When the winding 411B is energized, a magnetic field is generated in the second magnetic pillar 422B. In fig. 4B, the arrows on winding 411B represent the direction of current flow in the winding, and the dashed lines with arrows represent the magnetic induction lines in the core. The magnetic induction lines are used for describing the magnetic field generated by the winding 411B, and the magnetic induction lines are closed curves. As the path along which the magnetic induction lines travel in the first and

second yokes

423 and 424 is lengthened, the magnetic resistance of the path increases, since the magnetic induction lines always take the path with the smallest magnetic resistance (i.e., the largest magnetic permeability), and since the magnetic permeability of the first and second

magnetic pillars

421A and 421B is greater than that of the second and second

magnetic pillars

422A and 422C, the magnetic induction lines generated in the second magnetic pillar 422B by the winding 411B are more transmitted through the first and second

magnetic pillars

421A and 421B, a closed curve is formed in the magnetic core, and the magnetic induction lines are less transmitted through the second

magnetic pillars

422A and 422C. Further, the larger the difference in permeability between the first magnetic pillar 421A and the second magnetic pillar 422A is, the larger the difference in permeability between the first magnetic pillar 421B and the second magnetic pillar 422C is, and a larger proportion of magnetic induction lines in the second magnetic pillar 422B pass through the first magnetic pillar 421A and the first magnetic pillar 421B.

In one possible implementation, each magnetic pillar in integrated inductor 400 is located on the same plane, which is beneficial to reducing the volume of integrated inductor 400 and improving the power density of integrated inductor 400.

In the integrated inductor 400 shown in fig. 4a, each second magnetic pillar shares one first magnetic yoke 423 and one second magnetic yoke 424, or the first magnetic yoke 423 of each second magnetic pillar is obtained in the same one-time integral molding process, and the second magnetic yoke 424 of each second magnetic pillar is obtained in the same one-time integral molding process, which is beneficial to simplifying the processing process of the integrated inductor 400 and reducing the processing cost.

Fig. 4d is a bottom view of the integrated inductor 400 shown in fig. 4a, with reference to fig. 4a and 4d, in a possible implementation manner, a first end of each of the first and second magnetic pillars is respectively bonded to a lower surface of the first magnetic yoke 423 (i.e., a surface proximate to the magnetic pillar), a second end of each of the first and second magnetic pillars is respectively bonded to an upper surface of the second magnetic yoke 424 (i.e., a surface proximate to the magnetic pillar), and an air gap exists between the two bonded magnetic pillars.

In one possible implementation, first ends of some or all of the first and second magnetic pillars may be bonded to a side surface of the first yoke 423, and second ends of some or all of the first and second magnetic pillars may be bonded to a side surface of the second yoke 424.

Fig. 4a merely provides an exemplary implementation of the interconnection of the magnetic yoke and the magnetic pillar, and other implementations are described below with reference to fig. 4e to 4 g.

In a possible implementation manner, each second magnetic pillar has a separate first magnetic yoke 423 and a separate second magnetic yoke 424, the first magnetic yokes 423 of any two adjacent second magnetic pillars are connected through the first magnetic pillar between the two second magnetic pillars, the second magnetic yokes 424 of any two adjacent second magnetic pillars are connected through the first magnetic pillar between the two second magnetic pillars, and two ends of each first magnetic pillar are flush with the first magnetic yoke 423 and the second magnetic yoke 424, respectively, which is beneficial to improving the tolerance of the processing process of the integrated inductor 400 to process errors. Fig. 4e shows a side view and a bottom view of another possible structure of integrated inductor 400. The term "connected" as used herein may mean connected by bonding or other means as long as the magnetic induction lines can pass through the connected members while reducing magnetic leakage. Referring to fig. 4e, the first yoke 423 of the second magnetic pillar 422A is connected to the first yoke 423 of the second magnetic pillar 422B through the first magnetic pillar 421A, and the first yoke 423 of the second magnetic pillar 422B is connected to the first yoke 423 of the second magnetic pillar 422C through the first magnetic pillar 421B; the second yoke 424 of the second magnetic pillar 422A is connected to the second yoke 424 of the second magnetic pillar 422B through the first magnetic pillar 421A, and the second yoke 424 of the second magnetic pillar 422B is connected to the second yoke 424 of the second magnetic pillar 422C through the first magnetic pillar 421B.

In a possible implementation manner, part of the adjacent second magnetic columns share one first magnetic yoke 423, and the first magnetic yokes 423 of the part of the adjacent second magnetic columns are connected through the first magnetic column therebetween; the second yokes 424 of the partially adjacent second magnetic columns are connected through the first magnetic column therebetween. Fig. 4f shows side, top and bottom views of another possible structure of integrated inductor 400. Referring to fig. 4f, the first yoke 423 of the second magnetic pillar 422A is connected to the first yoke 423 of the second magnetic pillar 422B through the first magnetic pillar 421A, and the second magnetic pillar 422B and the second magnetic pillar 422C share one first yoke 423; the second magnetic pillar 422A and the second magnetic pillar 422B share a second magnetic yoke 424, and the second magnetic yoke 424 of the second magnetic pillar 422B is connected to the second magnetic yoke 424 of the second magnetic pillar 422C through the first magnetic pillar 421B.

In one possible implementation manner, each second magnetic pillar has a separate first magnetic yoke 423, and the first magnetic yokes 423 of any two adjacent second magnetic pillars are connected through the first magnetic pillar between the two second magnetic pillars; each second magnetic pole shares a second magnetic yoke 424. Fig. 4g shows a side view, a top view and a bottom view of another possible structure of the integrated inductor 400. Referring to fig. 4g, the first yoke 423 of the second magnetic pillar 422A is connected to the first yoke 423 of the second magnetic pillar 422B through the first magnetic pillar 421A, and the first yoke 423 of the second magnetic pillar 422B is connected to the first yoke 423 of the second magnetic pillar 422C through the first magnetic pillar 421B; the second magnetic pillar 422A, the second magnetic pillar 422B, and the second magnetic pillar 422C share one second yoke 424.

The structure of the integrated inductor provided in the embodiments of the present application is described above by taking the integrated inductor including 3 windings as an example. The following describes materials in the integrated inductor provided in the embodiments of the present application by way of example.

In one possible implementation, the second magnetic pillar of the integrated inductor may be made of a powder core material or a ferrite air gap composite material.

Alternatively, in a possible implementation manner, the first magnetic yoke and/or the second magnetic yoke are made of the same material as the second magnetic pillar.

In one possible implementation, the first yoke and the second yoke of the second magnetic pillar may be made of a powder core material or a ferrite air gap composite material.

In a possible implementation, the first magnetic pillar of the integrated inductor may be made of a multilayer strip with a high magnetic permeability, for example, an amorphous strip or a nanocrystalline strip, and more particularly, a multilayer amorphous or nanocrystalline metal strip.

In one possible implementation, the plane of any layer of the strip material in the first magnetic column is parallel to the first direction.

The structure of the first magnetic pillar will be described below by taking the first magnetic pillar 421A in FIG. 4b as an example.

Taking the example that the first magnetic pillar 421A includes three layers of tapes (tapes 421A1, 421A2, and 421A3, respectively), and the planes of the three layers of tapes are all parallel to the Y direction and the Z direction, i.e., parallel to the plane Y-Z, fig. 5a shows a possible partial schematic view of fig. 4b, and particularly shows the first magnetic pillar 421A, the first magnetic yoke 423 of the second magnetic pillar 422A, and the second magnetic yoke 424 of fig. 4 a.

The distribution of the lines of magnetic inductance in the integrated inductor 400 in different planes parallel to the plane X-Z is very small, and the distribution of the lines of magnetic inductance in the integrated inductor 400 in different planes parallel to the plane X-Z can be considered to be the same, so fig. 5a only illustrates one line of magnetic inductance (indicated by a dashed line with an arrow) in a plane parallel to the plane X-Z inside the first magnetic yoke 423 and the second magnetic yoke 424.

The magnetic paths of the induction lines passing through the strip 421a1, the strip 421a2 and the strip 421A3 are assumed to be the magnetic path 1, the magnetic path 2 and the magnetic path 3, respectively, as shown by the

curves

1, 2 and 3 in fig. 5 a. The longer the path the magnetic circuit experiences in the first yoke 423, the greater the reluctance of the magnetic circuit, and similarly, the longer the path the magnetic circuit experiences in the second yoke 424, the greater the reluctance of the magnetic circuit. The reluctance of the magnetic circuit 3 is therefore greater than the reluctance of the magnetic circuit 2, and the reluctance of the magnetic circuit 2 is greater than the reluctance of the magnetic circuit 1. As shown in fig. 5a, it is assumed that in the first yoke 423, the magnetic circuit 3 passes more than the magnetic circuit 2 by the magnetic resistance Rm2, and the magnetic circuit 2 passes more than the magnetic circuit 1 by the magnetic resistance Rm 1; in the second yoke 424, the magnetic circuit 3 passes more than the magnetic circuit 2 by the magnetic resistance Rm4, and the magnetic circuit 2 passes more than the magnetic circuit 1 by the magnetic resistance Rm 3. Since the magnetic induction lines always take 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 select the magnetic circuit 1 more, that is, the magnetic induction lines generated by the winding 411A are distributed unevenly in the strip 421A1, the strip 421A2 and the strip 421A3, the equivalent magnetic flux area of the first magnetic pillar 421A is reduced, and the first magnetic pillar 421A is more likely to be saturated by the magnetic flux.

In order to solve the above problem, in one possible implementation, the plane of any layer of the strip material in the first magnetic cylinder is parallel to the first direction and parallel to the second direction.

Still taking the example that the first magnetic pillar 421A includes three layers of tapes (tapes 421A1, 421A2, and 421A3, respectively), and the planes of the three layers of tapes are all parallel to the X direction and the Z direction, i.e. parallel to the plane X-Z, fig. 5b shows another possible partial schematic view of fig. 4b, specifically showing the first magnetic yoke 423 and the second magnetic yoke 424 of the first magnetic pillar 421A and the second magnetic pillar 422A in fig. 4 a.

Assume that the magnetic paths of the magnetic induction lines in the first yoke 423 and the second yoke 424 passing through the strip 421a1, the strip 421a2, and the strip 421A3 are the magnetic path 1, the magnetic path 2, and the magnetic path 3, respectively, as shown by the

curves

1, 2, and 3 in fig. 5 a. The distribution difference of the magnetic induction lines in the integrated inductor 400 in different planes parallel to the plane X-Z is small, and it can be considered that the distribution of the magnetic induction lines in the integrated inductor 400 in different planes parallel to the plane X-Z is the same, and the magnetic resistances of the magnetic circuit 1, the magnetic circuit 2 and the magnetic circuit 3 are the same, that is, the distribution of the magnetic induction lines generated by the winding 411A in the strip 421A1, the strip 421A2 and the strip 421A3 is uniform, the equivalent magnetic flux area of the first magnetic pillar 421A is larger, and the first magnetic pillar 421A is not prone to magnetic flux saturation.

In a possible implementation manner, inductance balance of the three windings can be achieved by adjusting the number of turns of the winding, or adjusting the size of an air gap between the second magnetic pillar corresponding to the winding and the first magnetic yoke and/or the second magnetic yoke, or adjusting the sectional area of the second magnetic pillar.

As can be seen by comparing the equivalent magnetic circuits in fig. 4B and 4C, if the magnetic induction lines entering the other second magnetic columns are not considered, 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), so that the magnetic induction lines generated by the

windings

411A and 411C all pass through a single first magnetic column; since the winding 411B is simultaneously adjacent to the two first magnetic pillars (the first magnetic pillar 421A and the first magnetic pillar 421B), a part of the magnetic induction lines generated by the winding 411B passes through the first magnetic pillar 421A, and another part of the magnetic induction lines passes through the first magnetic pillar 421B.

Magnetic paths through which magnetic induction lines generated by the

windings

411A, 411B, and 411C pass are referred to as a magnetic path a, a magnetic path B, and a magnetic path C, respectively. In order to balance the inductance of the three windings, in a possible implementation, the number of turns of the middle winding in the integrated inductor is smaller than the number of turns of the other windings. The middle winding is arranged on a second magnetic column between two first magnetic columns in the N-1 first magnetic columns, and other windings are other windings except the middle winding in the N windings.

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

In order to increase the heat dissipation area of each winding in the integrated inductor, in one possible implementation manner, the cross-sectional area of the second magnetic pillar of the integrated inductor on a plane perpendicular to the first direction is an ellipse or a rectangle.

The embodiment of the present application further provides a power converter, which is a multiphase power converter, and the integrated inductor in any of the embodiments of the present application is used as a filter inductor to suppress ripples in each phase of alternating current. Specifically, the power converter includes N switching legs and the integrated inductor in any embodiment of the present application, where the N switching legs correspond to N windings in the integrated inductor one to one, and a midpoint of each of the N switching legs is connected to an ac input end or an ac output end of the power converter through a corresponding winding.

For example, if the power converter is a rectifier, the midpoint of each switching leg is connected to a corresponding one of the ac input terminals through a corresponding one of the windings; if the power converter is an inverter, the midpoint of each switching leg is connected to a corresponding one of the ac output terminals via a corresponding one of the windings.

Illustratively, the power converter may be a three-phase inverter 100 as shown in fig. 1, and the three-phase inverter 100 is provided with an integrated inductor 400 as shown in fig. 4a, specifically, the first-stage inductors L1-1, L1-2 and L1-3 in fig. 1 correspond to three windings of the integrated inductor 400, i.e., winding 411A, winding 411B and winding 411C, respectively. The midpoint a1 of the switching leg 1101 of the three-phase inverter 100 is connected with the alternating current output end a3 through the L1-1 (i.e., the winding 411A), the C1 and the L1-2, and the winding 411A is used for suppressing ripples in the alternating current output by the midpoint a 1; a midpoint B1 of the switching bridge arm 1102 is connected with an alternating current output end B3 through an L2-1 (namely, a winding 411B), a C2 and an L2-2, and the winding 411B is used for suppressing ripples in the alternating current output by a midpoint B1; the midpoint C1 of the switching leg 1103 is connected to the ac output terminal C3 through L3-1 (i.e., winding 411C), C3 and L3-2, and the winding 411C is used to suppress the ripple in the ac power output from the midpoint C1.

The technical solutions provided by the present application are introduced in detail, and the present application applies specific examples to explain the principles and embodiments of the present application, and the descriptions of the above examples are only used to help understand the method and the core ideas of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. An integrated inductor is characterized by comprising a magnetic core and N windings, wherein the magnetic core comprises N-1 first magnetic columns and N second magnetic columns, the N windings are correspondingly arranged on the N second magnetic columns one by one, the magnetic permeability of the first magnetic columns is greater than that of the second magnetic columns, and N is a positive integer greater than 2;

the N-1 first magnetic columns and the N second magnetic columns are 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 columns in the N second magnetic columns are separated by one first magnetic column in the N-1 first magnetic columns;

the magnetic core further comprises a first magnetic yoke arranged at the first end and a second magnetic yoke arranged at the second end of each of the N second magnetic columns, wherein the first magnetic yoke and/or the second magnetic yoke are respectively bonded with the second magnetic columns.

2. The integrated inductor of claim 1, wherein the N second magnetic pillars share a first magnetic yoke and/or a second magnetic yoke, and the first magnetic yoke and/or the second magnetic yoke are integrally formed.

3. The integrated inductor of claim 2, wherein the N-1 first legs are disposed between the first and second yokes.

4. The integrated inductor of claim 1, wherein each of the N second legs corresponds to a first yoke and a second yoke, and wherein the two ends of the N-1 first legs are flush with the first yoke and the second yoke, respectively.

5. The integrated inductor according to any one of claims 1 to 4, wherein each of the N-1 first magnetic pillars is made of a multi-layered tape.

6. The integrated inductor of claim 5, wherein a plane of any one of the plurality of layers of strips is parallel to the first direction and the second direction.

7. The integrated inductor of claim 6, wherein the multilayer strip is an amorphous strip or a nanocrystalline strip.

8. The integrated inductor according to any one of claims 1 to 4, wherein the number of turns of a middle winding of the N windings is smaller than the number of turns of other windings, the middle winding is disposed on the second magnetic pillar located between any two first magnetic pillars of the N-1 first magnetic pillars, and the other windings are other windings than the middle winding of the N windings.

9. The integrated inductor according to any one of claims 1 to 4, wherein a cross-sectional area of a middle magnetic pillar of the N second magnetic pillars on a first plane perpendicular to the first direction is smaller than cross-sectional areas of other second magnetic pillars on the first plane, the middle magnetic pillar is a second magnetic pillar located between any two first magnetic pillars of the N-1 first magnetic pillars, and the other second magnetic pillars are other second magnetic pillars of the N second magnetic pillars except the middle magnetic pillar.

10. The integrated inductor of any one of claims 1 to 4, the material of the second magnetic pillar being close to the magnetic permeability of the material of the first and second magnetic yokes; or the first magnetic yoke and/or the second magnetic yoke are made of the same first material as the second magnetic column, and the first material is a powder core material or a ferrite air gap composite material.

11. A power converter, characterized by comprising N switching legs and an integrated inductor according to any one of claims 1 to 10, wherein the N switching legs correspond to N windings in the integrated inductor one-to-one, and wherein a midpoint of each of the N switching legs is connected to an ac input end or an ac output end of the power converter through a corresponding one of the windings.