Multi-phase system with power conversion device using through output coupled inductors and manufacturing method thereof

Abstract

The present invention relates to a multi-phase system comprising a power converter having at least two legs and a filtering device connected to the at least two legs of the power converter, the filtering device being composed of at least two inductors, each inductor being composed of a turn wound around a magnetic material, the magnetic material being disposed in at least one printed circuit board including connections of the inductors, the filtering device further comprising a conductive material surrounding the at least two inductors, a first terminal of each inductor being respectively connected to one leg of the power converter and one terminal of the conductive material being connected to another terminal of the inductor.

Description

[Technical Field]

[0001] The present invention generally relates to a through output coupled inductor. [Background technology]

[0002] Recent advances in semiconductor technology, specifically wide bandgap devices (WBG), have opened up the field for smaller power electronic systems. Driven by the superior dynamic performance of WBG switches compared to silicon switches, power converters can now operate at much higher switching frequencies. This directly corresponds to a relaxation of constraints on both inductive and capacitive filtering devices. Coupled with the power converter interleaving technique often used for high current applications, the volume and weight of magnetic components have been significantly reduced in recent years. An interleaved structure consists of parallel cells, also called legs. The drive signals for each leg are out of phase. Specifically, the phase shift can be evenly allocated according to the number of legs. If this condition is met, this structure can reduce the output current ripple by N, with an apparent frequency of N times Fsw (Fsw is the switching frequency of the power converter) and the HF voltage virtually divided by N. 2 This allows the current rating of the semiconductors to be reduced by a factor of 1 (where N is the number of legs). This distributes the design constraints on the devices, allowing the current rating of the semiconductors to be reduced. In interleaved converters that filter the output voltage, the filtering devices represent a significant part of the converter weight. The classical solution is to use separate inductors, but such a solution imposes a large weight, so the magnetic device concept is crucial.

[0003] On the other hand, the lack of significant improvements in magnetic materials forces designers to determine the optimum trade-off between saturation field and core losses.

[0004] Conventional inductors contain a DC (direct current) or LF (low frequency) magnetic field component superimposed on an HF (high frequency) component. Magnetic saturation is the most important issue to address when aiming for smaller inductors. HF induced magnetic field B HF varies independently of the magnetic permeability, but the low frequency or DC induced magnetic field B DC / LF It is also clear that DC / LF and HF magnetic fields can be treated separately, since

[0005] In the example shown in Figure 1a, the magnetization curve of the inductor can cause saturation of the induced magnetic field.

[0006] In Figure 1a, B LF represents the LF induced magnetic field, and B DC represents the DC induced magnetic field, and H LF represents the LF magnetic field, and H DC represents the DC magnetic field.

[0007] Based on these observations, compensating the LF / DC magnetic flux and operating the inductor in two magnetic field quadrants is the optimal option, as shown in Figure 1b. By doing so, the saturation constraints associated with the LF / DC magnetic fields are relaxed, i.e., the inductor is now designed almost as a transformer with only an HF component. One advantage of this solution is that the designed inductor is completely isolated from the current flowing through the device (apart from copper losses). Such a demagnetization method can be achieved by magnetically coupling at least two inductors carrying similar currents.

[0008] Therefore, the reduction of LF / DC magnetic fields can be achieved by adjusting the coupling coefficient between at least two inductors. LF / DC The value of F sw There is also a significant increase in current ripple, with N times the leakage inductance. swThe leakage inductance acts as a filtering device, removing N times higher current harmonics, but it is essential to keep the leakage inductance to a minimum to prevent HF losses from occurring, which can cause unacceptable levels of loss and even destruction of the filtering device. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to provide a filtering device in an interleaved structure of converters consisting of through output coupled inductors designed using PCB-based technology. [Means for solving the problem]

[0010] Essentially, each inductor is wound as a solenoid with turns arranged along the length of the device. Several conductor layers can be considered depending on the inductive requirements, the target AC resistance, and the overall capacitive behavior. The windings, called multiple solenoids, are mounted on a single substrate. Together, the substrate and the windings serve as a frame that incorporates the first part of each inductor's magnetic circuit. Coupling to the output current is achieved via a compensating turn made of a conductive foil.

[0011] Optionally, two plates made of magnetic material are mounted at the top and bottom to close a single magnetic path.

[0012] To that end, the present invention relates to a polyphase system comprising a power converter having at least two legs and a filtering device connected to at least two legs of the power converter, characterized in that the filtering device is composed of at least two inductors, each inductor being composed of turns wound around a magnetic material, the magnetic material being arranged in at least one printed circuit board including connections of the inductors, the filtering device further comprising a conductive material surrounding the at least two inductors, a first terminal of each inductor being connected to one leg of the power converter, and one terminal of the conductive material being connected to another terminal of the inductor.

[0013] Therefore, in this configuration, the two inductors are F sw At N times the frequency (N is the number of legs), they are magnetically coupled through the conductive material, and at other frequencies they are isolated, providing efficient filtering.

[0014] According to a particular feature, the filtering device comprises one printed circuit board having at least two cavities in which at least two magnetic materials are respectively placed.

[0015] The printed circuit board thus serves as an assembly frame, mechanically holding the filtering device and incorporating the magnetic core, and as a result, this frame can be used in the lamination process if additional layers are required on the aforementioned printed circuit board.

[0016] According to a particular feature, the printed circuit board further comprises, per cavity, two spaces for inductors wound around a magnetic core.

[0017] Thus, the printed circuit board also serves as the magnetic yoke for the inductor, with no assumptions made on the winding technique other than that it must be wound directly on the printed circuit board.

[0018] According to a particular feature, the printed circuit board further comprises, per cavity, two spaces for inserting the inductor wound around a magnetic core and the magnetic core.

[0019] Therefore, with this feature, the windings can be manufactured separately and mounted on the printed circuit board by inserting them through the space, which allows for the use of specialized manufacturers that design the windings without the need for a printed circuit board, thereby realizing a more versatile process.

[0020] According to particular features, the filtering device comprises a first printed circuit board, a second printed circuit board, and a third printed circuit board, the third printed circuit board having at least two cavities in which at least two magnetic materials are respectively placed, the first printed circuit board and the second printed circuit board having conductors, and the conductors of the first printed circuit board and the second printed circuit board being electrically connected to form windings of an inductor.

[0021] Therefore, this design can benefit from a cost-effective and simplified PCB process, and additional functions such as PCB-embedded sensors can be implemented on the printed circuit board together with the windings.

[0022] According to a particular feature, the conductive material surrounding the at least two inductors is U-shaped.

[0023] The component is therefore easy to manufacture, and because the input and output of the conductors are located on the same side (opposite sides of the U-bend), the overall mechanical design and required interconnections are simplified.

[0024] According to a particular feature, the filtering device is surrounded by a magnetic element.

[0025] The present invention also provides a method for manufacturing a polyphase system comprising a power converter having at least two legs and a filtering device connected to the at least two legs of the power converter, the filtering device being comprised of at least two inductors, the method comprising: disposing a magnetic material within at least one printed circuit board including connections for the inductor; For each inductor, arranging a turn wound around a magnetic material; providing a conductive material surrounding the at least two inductors; connecting a first terminal of each inductor to one leg of the power converter and connecting one terminal of the conductive material to another terminal of the inductor, thereby connecting the filtering device; The present invention relates to a method comprising the steps of:

[0026] The characteristics of the invention will emerge more clearly from a reading of the following description of exemplary embodiments, the said description being made with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0027] [Figure 1a] FIG. 10 shows the magnetization curves of the filtering device in the interleaved structure of the converter. [Figure 1b] FIG. 10 shows the magnetization curves of the filtering devices in an interleaved structure of a converter with a through output coupling inductor according to the present invention. [Figure 2] 1 shows an example for realizing an interleaved structure of converters with filtering devices made up of through-output coupled inductors according to the present invention; [Figure 3] FIG. 1 shows a more detailed example for realizing an interleaved structure of converters with filtering devices made up of through-output coupled inductors according to the invention. [Figure 4]FIG. 1 shows a first example for realizing two inductors of a filtering device, realized using a printed circuit board. [Figure 5] FIG. 10 shows a second example for realizing an inductor of a filtering device, realized using a printed circuit board. [Figure 6] 1A and 1B are diagrams illustrating a first example of a through output coupled inductor according to the present invention. [Figure 7] FIG. 1 illustrates the architecture of a system for creating filtering devices in an interleaved structure of converters with through output coupling inductors. [Figure 8] FIG. 10 shows an algorithm for creating a filtering device in an interleaved structure of converters with through output coupling inductors. DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 2 shows an example for realizing an interleaved structure of converters comprising a filtering device according to the invention.

[0029] In the example of Figure 2, the converter has N legs. Switch Q 11 and Q 12 is the switch of the first leg 1 and is connected to the first terminal of the inductor L1.

[0030] Switch Q i1 and Q i2 is the switch of the ith leg i, and the inductor L i The first terminal of switch Q is connected to the N1 and Q N2 is the switch of the Nth leg N, and the inductor L N is connected to the first terminal of the

[0031] Inductors L1 and L i , and L N The other terminal of the inductor L' Nand the first terminal of the inductor L' N The other terminal of the inductor L' i and the first terminal of the inductor L' i The other terminal of is connected to the first terminal of the inductor L'1. As shown in FIG. 2, the inductors L1 and L'1 are magnetically coupled, and the inductor L i and L' i are magnetically coupled, and the inductor L N and L' N are magnetically coupled.

[0032] Here, L i Each magnetic device labeled with an output current I Σ Another magnetic device that flows through L' i is connected to

[0033] When these magnetic devices are coupled, this theoretically allows for L i The inductors are connected together at L' i This configuration allows for greater design freedom or freedom from constraints on magnetic layout, since only the coupling between a phase and its output conductor needs to be managed. This allows for cancellation or partial compensation of the LF / DC flux, depending on the turns ratio.

[0034] More precisely, as shown in FIG. 3, inductors L1 and L'1 are magnetically coupled using magnetic material M1, and inductor L i and L' i is the magnetic material M i are magnetically coupled using inductor L N and L' N is the magnetic material M N The magnetic materials M1 to M N is realized using a toroidal core structure made of magnetic material such as ferrite, nanocrystalline, or iron powder, depending on the required loss level.

[0035] FIG. 4 shows a first example for realizing two inductors of a filtering device, realized using a printed circuit board.

[0036] In the example of FIG. 4, each inductor L1 or L N is wound as a solenoid with turns arranged in the longitudinal direction of the filtering device. N The terminals of have electrical connections Co which are, for example, part of a copper layer of a printed circuit board PCB.

[0037] Inductor L1 or L N For each, the printed circuit board contains magnetic material M1 or M N There is a cavity in which the inductor L1 or L2 is placed. Several conductor layers can be considered depending on the inductance requirements, the target AC resistance, and the overall capacitive behavior. N The wires making up the inductor, shown as thick black lines in the example of Figure 4, are wound around a magnetic material. The wound inductor and magnetic material are inserted into respective cavities C1 and C2 in the printed circuit board. N In some variations, the magnetic material is placed in each of the cavities C1 and C2. N and inductor L1 or L N is wound around the magnetic material. This is because the spaces Sp1 and Sp2 are extended by the openings shown by the dotted lines in Figure 4. N , Sp'1, and Sp' N Because there is.

[0038] Both the PCB and the windings are made of magnetic material M1 or M N It serves as a framework for incorporating

[0039] FIG. 5 shows a second example for realizing the inductor of the filtering device, which is realized using a printed circuit board.

[0040] In the example in Figure 5, the inductor L i is shown. The inductor L iis realized using a number of printed circuit boards PCB1, PCB2 and PCB3.

[0041] The printed circuit PCB3 contains magnetic material M i There is a cavity in which the

[0042] The printed circuit board PCB1 comprises an insulating layer on which a conductive layer is disposed, and is either a castellated board or comprises flex terminals.

[0043] The printed circuit board PCB2 comprises an insulating layer on which a conductive layer is disposed, and is either a castellated board or comprises flex terminals.

[0044] The insulating layer of the printed circuit board PCB2 is placed on the bottom of the printed circuit board PCB3, and the insulating layer of the printed circuit board PCB1 is placed on top of the printed circuit board PCB3.

[0045] Inductor L i is the conductive layer L i1 , flex terminal or castellation L of printed circuit board PCB1 i2 and L i8 , soldering L i3 and L i9 , via L on printed circuit board PCB3 i4 and L i10 , conductive layer L i7 , flex terminal or castellation L of printed circuit board PCB1 i6 and L i11 , and soldering L i5 and L i12 It is made of.

[0046] FIG. 6 shows a through output coupled inductor according to the present invention.

[0047] According to the invention, the compensation turn L' Nis realized using a conductive foil (copper or aluminum). This single conductor is designed to be implemented to compensate the LF magnetic field in each integrated inductor. In one possible implementation, the compensation turn L' N L' Na , L' Nb , and L' Nc The compensating turn L' has a U-shape made of a single compensating turn. In a multi-compensating turn configuration, the winding can be designed using either concentric foils or folded metal strips to obtain a solenoid-like shape. The choice of which solution depends on the rated current and the desired AC resistance. Whatever the shape chosen, the compensating turn L' N The main turn L is connected N is placed on top of the

[0048] In one possible implementation, the compensation turn L'1 or L' i is the member L' Nb and L' Nc It consists of only

[0049] Finally, the magnetic path is closed using the top, side and bottom magnetic plates Sh, which may consist of, for example, two C-shaped plates or one C-shaped and one I-shaped magnetic plate.

[0050] FIG. 7 shows a system architecture for fabricating filtering devices in an interleaved structure of converters with through output coupling inductors.

[0051] The system 70 has, for example, an architecture based on components connected by a bus 801 and a processor 800 controlled by a program as disclosed in FIG.

[0052] The bus 701 links the processor 700 to a read-only memory ROM 702 , a random access memory RAM 703 and an input / output I / O IF interface 705 .

[0053] The input / output I / O IF interface 705 allows for the control of the various devices used to manufacture the filtering device with through output coupled inductors.

[0054] The memory 703 includes registers intended to contain variables and instructions of the programs related to the algorithm disclosed in FIG.

[0055] The read-only memory, or possibly flash memory 702, contains instructions for a program related to an algorithm such as that disclosed in Figure 8. This program is loaded into the random access memory 703 when the system 70 is powered up. Alternatively, this program can be executed directly from the ROM memory 702.

[0056] The system 70 may be implemented in software by the execution of a set of instructions or programs by a programmable computing machine such as a PC (personal computer), DSP (digital signal processor) or microcontroller, or may be implemented in hardware by a machine or dedicated components such as an FPGA (field programmable gate array) or ASIC (application specific integrated circuit).

[0057] In other words, the system 70 comprises circuitry, or a device comprising circuitry, that causes the system 70 to execute a program associated with an algorithm such as that disclosed in FIG.

[0058] FIG. 8 shows an algorithm for creating filtering devices in an interleaved structure of converters with through output coupling inductors.

[0059] The present algorithm discloses a method for producing a polyphase system comprising a power converter having at least two legs and a filtering device connected to the at least two legs of the power converter.

[0060] In step S80, magnetic material is placed within at least one printed circuit board that includes the connections of the inductor.

[0061] In step S81, each inductor turn is wound around this magnetic material.

[0062] In one variant of realization, the turns of each inductor are wound around a magnetic material and placed in at least one printed circuit board containing the connections of the inductors.

[0063] In step S82, a conductive material is placed surrounding the at least two inductors.

[0064] In step S83, the filtering devices are connected by respectively connecting a first terminal of each inductor to one leg of the power converter and connecting one conductive terminal to the other terminal of the inductor.

[0065] Naturally, many modifications can be made to the embodiments of the invention described above without departing from the scope of the invention.

Claims

1. 1. A polyphase system comprising: a power converter having at least two legs; and a filtering device connected to the at least two legs of the power converter, wherein the filtering device is comprised of at least two inductors, each inductor being comprised of a winding wound around a magnetic material, the magnetic material being disposed in at least one printed circuit board having a connection for connecting the at least two inductors, the filtering device further comprising a conductive material surrounding the at least two inductors, a first terminal of each inductor being connected to one leg of the power converter, one terminal of the conductive material being connected to another terminal of the inductor, and the at least two inductors being magnetically coupled via the conductive material.

2. 2. The multi-phase system of claim 1, wherein the filtering device comprises a printed circuit board having at least two cavities in which at least two of the magnetic materials are individually located.

3. 3. The multi-phase system of claim 2, wherein said printed circuit board further comprises two spaces for each said cavity adjacent said cavity for said windings wound around said magnetic material.

4. 2. The multi-phase system of claim 1, wherein the filtering device comprises three printed circuit boards, a first printed circuit board, a second printed circuit board, and a third printed circuit board, the third printed circuit board having a cavity in which the magnetic material is disposed, the first printed circuit board and the second printed circuit board each having a conductor, the conductors of the first printed circuit board and the second printed circuit board electrically connected to form a winding of the inductor.

5. 5. The multi-phase system of claim 4, wherein said conductive material surrounding said at least two inductors is U-shaped.

6. 1. A method of manufacturing a polyphase system comprising a power converter having at least two legs and a filtering device connected to the at least two legs of the power converter, the filtering device being comprised of at least two inductors, the method comprising: disposing a magnetic material in at least one printed circuit board having connections for connecting the at least two inductors; For each inductor, arranging a winding wound around the magnetic material; providing a conductive material surrounding the at least two inductors; connecting the filtering device by connecting a first terminal of each inductor to one leg of the power converter and connecting one terminal of the conductive material to another terminal of the inductor, wherein the at least two inductors are magnetically coupled via the conductive material; A method comprising:

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