Coupling winding and multiphase coupling inductor

Abstract

The invention relates to the technical field of electronic magnetic elements, and discloses a coupling winding and a multi-phase coupling inductor. Wherein the coupling winding comprises N-phase windings, each phase winding comprises a main winding and an interlaced winding, the main winding and the interlaced winding are connected in series, the main winding is wound on the side column of the phase, and the interlaced winding is wound on the side column of the adjacent next phase in a bridging manner; and the N phases of windings are sequentially and circularly connected to form a cyclic symmetric topology, so that two adjacent phases of winding layers with inherent phase difference are simultaneously stacked on any magnetic column to realize active offset of interlayer magnetomotive force. According to the invention, each phase of winding is arranged to be of a series structure of the main winding and the staggered winding, and a cyclic symmetric cross-phase arrangement mode is adopted, so that two adjacent phase winding layers with an inherent phase difference are stacked on the same magnetic column at the same time, and interlayer magnetomotive force active offset can be realized by using a natural current phase difference of a multi-phase system; eddy-current loss caused by the high-frequency proximity effect is inhibited from the source, and high-frequency alternating-current copper loss of the magnetic element is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of electronic magnetic components, and in particular to a coupled winding and a multiphase coupled inductor. Background Technology

[0002] In high step-down ratio power electronic converters such as those used in data centers and new energy vehicles, increasing the switching frequency is a key method to reduce the size of magnetic components. To reduce high-frequency switching losses, critical conduction mode (CRM) is widely used, but its inductor current ripple factor is as high as 200%. Large-amplitude high-frequency triangular wave currents can induce proximity effects in planar windings, leading to a sharp increase in AC resistance.

[0003] Existing multiphase coupled inductors employ a single-phase independent stacked winding structure, where each phase winding is individually wound on its corresponding end post. The currents in each layer within the core window are completely in phase, resulting in linear superposition and amplification of the interlayer magnetomotive force (MMF), further exacerbating proximity effect eddy current losses. This structure has an optimal copper thickness limitation, making it impossible to reduce DC resistance solely by increasing the copper conductor thickness. This leads to persistently high total copper losses in the magnetic components, becoming a bottleneck restricting the high-frequency and miniaturization of converters.

[0004] Therefore, there is an urgent need for a coupled winding and multiphase coupled inductor structure that can suppress proximity effects at the source and break the optimal copper thickness limit. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a coupled winding and a multiphase coupled inductor.

[0006] The technical solution of this invention is implemented as follows: According to a first aspect of the invention, a coupling winding is provided.

[0007] The coupling winding includes: An N-phase winding consists of a main winding and an interleaved winding in each phase. The main winding and the interleaved winding are connected in series. The main winding is wound on the side post of the current phase, and the interleaved winding is wound across the side post of the next adjacent phase. N is a positive integer and is greater than or equal to 2.

[0008] In this system, the N-phase windings are sequentially connected to form a cyclic symmetrical topology, so that two adjacent phase winding layers with an inherent phase difference are stacked on any magnetic column at the same time, so as to achieve active cancellation of the interlayer magnetomotive force.

[0009] Optionally, each phase winding has an open, non-closed structure in the shape of an "8".

[0010] In this circuit, the winding direction of each phase winding is unidirectional clockwise. The current flows in from a single input terminal, flows through the main winding and the interleaved winding in sequence, and then flows out from a single output terminal.

[0011] The winding method for each phase winding is as follows: first, half a turn is wound on the current phase magnetic post, then Ny turns are wound on the adjacent next phase magnetic post, and finally Nx-1 turns are wound back on the current phase magnetic post. Where Nx is the total number of turns in the main winding and Ny is the number of turns in the interleaved winding, and both Nx and Ny are positive integers.

[0012] Optionally, the number of turns Nx in the main winding is 2, and the number of turns Ny in the interleaved winding is 1.

[0013] The number of phases in the N-phase winding is matched with the fundamental phase difference between two adjacent phases: when N is 2, it is a two-phase winding with a fundamental phase difference of 180°; when N is 4, it is a four-phase winding with a fundamental phase difference of 90°; when N is 8, it is an eight-phase winding with a fundamental phase difference of 45°.

[0014] Optionally, the coupling winding can be any one of a planar PCB winding, a flat copper foil winding, or a thick copper busbar winding.

[0015] Optionally, adjacent phase windings can be stacked alternately on the same magnetic post.

[0016] According to a second aspect of the present invention, a multiphase coupled inductor is provided.

[0017] The multiphase coupled inductor includes: a magnetic core and a coupling winding as described in any one of claims 1-9; the magnetic core includes one common center post and N side posts, where N is an integer greater than or equal to 2, and the number of side posts corresponds one-to-one with the number of phases of the coupling winding.

[0018] The technical solution provided by this invention may include the following beneficial effects: This invention sets each phase winding in a series structure of main winding and interleaved winding, and adopts a cyclically symmetrical cross-phase arrangement, so that adjacent two-phase winding layers with inherent phase difference are stacked on the same magnetic column at the same time. The natural current phase difference of the multiphase system can be used to actively cancel the interlayer magnetomotive force, suppress the eddy current loss caused by high-frequency proximity effect from the root, and significantly reduce the high-frequency AC copper loss of magnetic components.

[0019] This winding structure breaks through the optimal copper thickness limitation of traditional coupled windings, and can be made with thick copper conductors, effectively reducing DC resistance without changing the total number of turns of the winding and the steady-state electrical characteristics of the multiphase system.

[0020] The four-phase winding topology can also passively induce phase current waveform distortion, transferring the current ripple energy from the fundamental frequency band to the second harmonic frequency band where the magnetic field can be completely canceled, thus forming a synergistic optimization of structure and waveform loss, further minimizing the total loss of magnetic components.

[0021] Meanwhile, the coupling winding and multiphase coupling inductor can be flexibly adapted to multiphase power conversion systems with different phase numbers such as two-phase, four-phase, and eight-phase. The phase number expansion is strong and can meet the usage requirements of devices with different power levels. It is especially suitable for high step-down ratio power electronic conversion scenarios in critical conduction mode. It can effectively reduce the size of magnetic components and promote the development of high frequency and miniaturization of converters. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0023] Figure 1 This is a schematic diagram of the single-phase winding structure of the present invention; Figure 2 This is a three-dimensional structural diagram of the four-phase coupled inductor of the present invention; Figure 3 This is a comparative schematic diagram of the single-phase winding structure of the present invention; Figure 4 This is a cross-sectional view of the magnetomotive force cancellation mechanism of the present invention; Figure 5 This is a comparison diagram of the phase current waveforms of the present invention and the traditional structure; Figure 6 This is a top view of the two-phase rotating interleaved coupled inductor structure of the present invention; Figure 7 This is a top view of the four-phase rotating interleaved coupled inductor structure of the present invention; Figure 8 This is a top view of the eight-phase rotating interleaved coupled inductor structure of the present invention.

[0024] Figure label: 101. Main winding; 102. Interleaved winding; 103. Input terminal; 104. Output terminal; 105. Layer switching bridging part; 201. Side post; 202. Common center post. Detailed Implementation

[0025] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1As shown, this embodiment of the invention provides a coupling winding, comprising: an N-phase winding, each phase winding including a main winding 101 and an interleaved winding 102, the main winding 101 and the interleaved winding 102 being connected in series, the main winding 101 being wound on the side post of the current phase, and the interleaved winding 102 being wound across the side post of the next adjacent phase; wherein, N is a positive integer and is greater than or equal to 2; the N-phase windings are sequentially cyclically connected to form a cyclic symmetrical topology, so that two adjacent phase winding layers with an inherent phase difference are simultaneously stacked on any magnetic post, so as to achieve active cancellation of interlayer magnetomotive forces.

[0027] In practical applications, such as Figure 1 As shown, the single-phase winding of the present invention presents an open, non-closed structure in the physical space in the shape of an "8". Figure 1 The arrows in the diagram indicate the direction of current flow. The winding direction of each phase winding is unidirectional clockwise. The current flows in from a single input terminal 103, flows through the main winding 101 and the interleaved winding 102 in sequence, and then flows out from a single output terminal 104.

[0028] The winding method for each phase can be as follows: first, half a turn is wound on the current phase magnetic post, then Ny turns are wound on the adjacent next phase magnetic post, and finally Nx-1 turns are wound back on the current phase magnetic post. Each phase winding has a rotating and interleaved structure. Here, Nx is the total number of turns in the main winding, and Ny is the number of turns in the interleaved winding; both Nx and Ny are positive integers. Preferably, the number of turns in the main winding Nx is 2, and the number of turns in the interleaved winding Ny is 1.

[0029] like Figure 1 As shown in the “Layer Switching Bridging Section 105”, a three-dimensional layer switching avoidance structure is adopted in the crossover area where the main winding 101 transitions to the interleaved winding 102. If a multilayer PCB process is used, the bridging is achieved through different conductive layers and metallized vias; if a flat copper busbar / thick copper foil is used, the bridging is achieved through stepped bending and stacking supplemented with insulation, thereby completing the lateral spatial transition while avoiding electrical short circuits.

[0030] like Figure 2 As shown, taking a four-phase coupled inductor as an example, the four-phase coupled inductor according to an embodiment of the present invention adopts a core structure comprising four side posts 201 and a common center post 202. The winding of each phase is no longer limited to a single side post, but consists of two parts connected in series: the main winding 101, wound on its corresponding side post; and the interleaved winding 102, connected across the adjacent next phase side post. The four-phase windings are connected end-to-end to form a cyclic symmetrical structure. Therefore, each core window (i.e., between two adjacent posts) simultaneously contains windings of two adjacent phases (with a 90° fundamental phase difference) stacked alternately.

[0031] like Figure 3As shown in (b), in a traditional four-phase coupled inductor, a single-phase winding is independently and centrally wound on a single side post. This means that when multiple phases are assembled into the same core, all conductor layers stacked within any winding window carry currents that are completely in phase. This inevitably leads to a unidirectional linear accumulation of the interlayer magnetic field strength (MMF) in the higher conductors, thus inducing an extremely severe proximity effect. In contrast, as Figure 3 As shown in (a), the rotary interleaved single-phase winding proposed in this invention breaks the physical isolation limitation of "one phase, one column". The physical routing of its single-phase conductors spatially spans two adjacent columns: the first part serves as the main winding 101 wound on the column of this phase, and the second part extends out as the interleaved winding 102 wound on the adjacent column. When four... Figure 3 The single-phase winding shown in (a) is arranged according to Figure 2 After the topology is sequentially spliced ​​together, in any winding window of the magnetic core, a staggered arrangement of conductor layers "from two phases with an inherent phase difference of 90°" is formed.

[0032] In a rotating staggered structure, the currents in adjacent layers have a phase difference θ. Therefore, the magnetic field environment of the k-th layer is no longer a simple algebraic sum, but rather the sum of multiple vectors with the same amplitude but different phases. Since the harmonics of the CRM current have different phase differences between adjacent phases (e.g., the fundamental is 90°, and the second harmonic is 180°), the resulting magnetic field vectors and their amplitudes will also differ. This difference directly determines the structure's ability to suppress losses from harmonics of different frequencies. Figure 4 As shown: For second harmonics ( Figure 4 (b) At this point, the phase difference between adjacent phase currents is exactly 180° (out of phase). The positive MMF generated by the current in the upper layer is completely canceled out by the reverse MMF generated by the current in the lower layer, and the magnetic field strength amplitude of each layer is at an extremely low level. This proves that the structure has a very strong loss suppression capability for second harmonics.

[0033] For fundamental frequency and third harmonic ( Figure 4 (a) and Figure 4 (c) The phase difference between adjacent phases is 90° and 270°. The interlayer MMFs are neither completely canceled nor completely superimposed, and their magnetic field strength amplitude is reduced to a certain extent compared with in-phase superposition. This indicates that the structure has a moderate suppression effect on odd-order harmonics.

[0034] For the fourth harmonic ( Figure 4 (d) The currents in adjacent layers are completely in phase, and the MMF distribution exhibits the same linear accumulation characteristics as in simple stacked windings. This structure does not have the ability to suppress fourth harmonic losses.

[0035] Because the alternating windings cause asymmetry in the mutual inductance between phases, this topology naturally leads to distortion in the phase current waveform (exhibiting a multi-slope sawtooth wave, such as...). Figure 5 (As shown).

[0036] This distortion caused by the topology passively shifts the fundamental energy, which originally dominated the alternating current, significantly to the second harmonic frequency band. Since the physical structure of this invention has the strongest magnetic field cancellation effect on the second harmonic, this synergistic effect of "structure-induced waveform change and waveform matching structural advantages" reduces the overall AC copper loss of the device to an extremely low level.

[0037] The above example uses a four-phase interleaved system (90° phase difference), but this core idea can also be extended to other multi-phase systems such as two-phase (180° phase difference, directly canceling fundamental wave loss) and eight-phase (45° phase difference). Simply adjust the bridging logic sequence of the windings according to the system's phase difference characteristics, as shown in the example below. Figure 6-8 As shown.

[0038] Figures 6-8 The diagrams, in turn, show two-dimensional top-down schematics of two-phase, four-phase, and eight-phase staggered winding structures. The gray-filled circles represent the side posts and center posts of the magnetic core. Thick solid lines and thick dashed lines are used alternately to clearly distinguish the winding traces of different electrical phases on the two-dimensional plane. All single-phase windings in the diagrams have clearly defined current input and output terminals. In the actual three-dimensional physical structure, the overlapping portions of solid and dashed lines on the same side post are insulated and spatially bridged using a three-dimensional layer-change avoidance structure (vias or stepped staggered stacking).

[0039] Specifically, for a two-phase rotating interleaved coupled inductor (for a system with a 180° phase difference), the structural characteristics are as follows: Figure 6 As shown, the magnetic core comprises two side posts and one center post. The system includes... i 1 and i 2. Two-phase windings. For example... i The main winding of winding 1 (solid line) surrounds side post 1, and then crosses to the left, with its interleaved winding surrounding side post 2; i The main winding of the second winding (dashed line) surrounds the side post 2, and then crosses over to the right, with its interleaved winding surrounding the side post 1. The two-phase windings form a complete interleaved overlap on the two side posts.

[0040] Working principle and effect: In a two-phase interleaved system, the fundamental phase difference between the two-phase currents is exactly 180° (i.e., completely out of phase). When they are interleaved in the same side column window, the high-frequency positive magnetomotive force (MMF) generated by the upper conductor and the reverse magnetomotive force generated by the lower conductor are perfectly canceled out. This structure can completely suppress fundamental AC losses and greatly improve the high-frequency efficiency of the two-phase high-current power supply module.

[0041] For a four-phase rotating interleaved coupled inductor (for a 90° phase difference system), the structural characteristics are as follows: Figure 7 As shown: The magnetic core consists of four side posts (arranged in a square array) and one center post. Four-phase winding ( i 1~ i 4) Forming a circular connection in space. i 1. Winding 1 surrounds side posts 1 and 2; i 2 windings surround side posts 2 and 3; i 3 windings surround side posts 3 and 4; i Four windings surround side posts 4 and 1. Each side post has windings for two adjacent phases.

[0042] Working Principle and Effect: The fundamental phase difference of the four-phase system is 90°. Due to the asymmetrical mutual inductance introduced by the rotating interleaved phases, the system passively transfers most of the current ripple energy to the second harmonic frequency band; and the phase difference of the second harmonics in the four-phase system is exactly 2 × 90° = 180°. The second harmonic currents of adjacent layers at a 180° angle achieve magnetic field cancellation in space. This structure, through the synergy of waveform distortion and structural advantages, specifically targets the perfect cancellation of 4k+2 type even harmonics, breaking through the high-frequency copper thickness limitation of traditional four-phase systems.

[0043] For an eight-phase rotary interleaved coupled inductor (for a 45° phase difference system), the structural characteristics are as follows: Figure 8 As shown, the magnetic core comprises eight side posts (arranged in a ring) and one center post. Eight-phase windings ( i 1~ i 8) Connect the phases in a ring sequence. For example... i One winding surrounds side posts 1 and 8. i Two windings surround side posts 2 and 1, and so on, forming a higher-order cyclic symmetric topology.

[0044] Working principle and effect: The fundamental phase difference of the eight-phase interleaved system is 360° / 8 = 45°. According to the principle of harmonic phase accumulation, the relative phase difference of its fourth harmonic is exactly 4 × 45° = 180°. This eight-phase interleaved structure can also achieve good interlayer magnetic field cancellation for high-frequency harmonics.

[0045] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A coupling winding, characterized in that, include: An N-phase winding consists of a main winding and an interleaved winding in each phase. The main winding and the interleaved winding are connected in series. The main winding is wound on the side post of the current phase, and the interleaved winding is wound across the side post of the next adjacent phase. N is a positive integer and is greater than or equal to 2.

2. The coupling winding according to claim 1, characterized in that, The N-phase windings are sequentially connected to form a cyclic symmetrical topology, so that two adjacent phase winding layers with an inherent phase difference are stacked on any magnetic column at the same time, so as to achieve active cancellation of the interlayer magnetomotive force.

3. A coupling winding according to claim 1, characterized in that, Each phase winding has an open, non-closed structure in the shape of an "8".

4. A coupling winding according to claim 1, characterized in that, The winding direction of each phase winding is unidirectional clockwise. The current flows in from a single input terminal, flows through the main winding and the interleaved winding in sequence, and then flows out from a single output terminal.

5. A coupling winding according to claim 4, characterized in that, The winding method for each phase winding is as follows: first, half a turn is wound on the current phase magnetic post, then Ny turns are wound on the adjacent next phase magnetic post, and finally Nx-1 turns are wound back on the current phase magnetic post. Where Nx is the total number of turns in the main winding and Ny is the number of turns in the interleaved winding, and both Nx and Ny are positive integers.

6. A coupling winding according to claim 5, characterized in that, The main winding has 2 turns Nx and the interleaved winding has 1 turn Ny.

7. A coupling winding according to claim 1, characterized in that, The number of phases in the N-phase winding is matched with the fundamental phase difference between two adjacent phases: When N is 2, it is a two-phase winding with a fundamental phase difference of 180°; When N is 4, it is a four-phase winding with a fundamental phase difference of 90°; When N is 8, it is an eight-phase winding with a fundamental phase difference of 45°.

8. A coupling winding according to claim 1, characterized in that, The coupling winding can be any one of a planar PCB winding, a flat copper foil winding, or a thick copper busbar winding.

9. A coupling winding according to claim 1, characterized in that, Adjacent phase windings are stacked alternately on the same magnetic column.

10. A multiphase coupled inductor, characterized in that, include: The magnetic core is coupled to the coupling winding as described in any one of claims 1-9; the magnetic core includes one common center post and N side posts, where N is an integer greater than or equal to 2, and the number of side posts corresponds one-to-one with the number of phases of the coupling winding.

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