CN-122025365-A - Integrated magnetic element based on hybrid winding and design method

CN122025365ACN 122025365 ACN122025365 ACN 122025365ACN-122025365-A

Abstract

The invention discloses an integrated magnetic element based on a hybrid winding and a design method, belongs to the technical field of power electronics, and aims to solve the problems that an existing planar transformer is large in winding loss, difficult in leakage inductance adjustment and limited in power density due to the fact that independent resonant inductors are required to be externally connected in a high-frequency and high-turn number application scene. The integrated magnetic element comprises a magnetic core, a primary winding, a secondary winding and a planar PCB winding, wherein the magnetic core is provided with a first side column, a second side column and a middle column, air gaps are arranged on the three columns, the primary winding is wound by Litz wires and is respectively connected with the three columns in series, and the secondary winding is only wound on the middle column by adopting a planar PCB winding, and the winding direction of the secondary winding is opposite to that of the primary winding. The leakage inductance is configured to be the resonance inductance value required by the LLC resonant converter by adjusting the air gap length of each magnetic pole and the turn number distribution of the primary winding, so that the magnetic integration of the transformer and the resonance inductance is realized. The invention also provides a corresponding design method. According to the invention, the Litz wire is combined with the PCB winding, and meanwhile, an external resonance inductor is omitted through magnetic integration.

Inventors

GAO DONGHUI
GUAN LESHI
SUN PENGFEI
Na Yingsi
LI XIANG
Wu youran
ZHU WEILONG

Assignees

哈尔滨工业大学
中国电子科技集团公司第四十三研究所

Dates

Publication Date: 20260512
Application Date: 20260409

Claims (10)

1. An integrated magnetic component based on a hybrid winding, comprising: the magnetic core comprises a first side column, a second side column and a middle column positioned between the first side column and the second side column, wherein air gaps are formed in the first side column, the second side column and the middle column; The primary winding is wound by Litz wires and is respectively connected in series with the first side column, the second side column and the middle column; The secondary winding adopts a planar PCB winding, is only wound on the middle column, and has a winding direction opposite to that of the primary winding on the middle column; the leakage inductance value of the integrated magnetic element is configured to be the resonance inductance value required by the LLC resonant converter by adjusting the air gap lengths of the first side column, the second side column and the middle column and the turn number distribution of the primary winding on each magnetic column, so that the magnetic integration of the transformer and the resonance inductance is realized.
2. The hybrid winding-based integrated magnetic component of claim 1, wherein the first leg and the second leg are symmetrically disposed, have equal magnetic circuit cross-sectional areas and equal air gap lengths, and the number of turns of the primary winding on the first leg is equal to the number of turns on the second leg.
3. The integrated magnetic component based on the mixed winding according to claim 1, wherein the excitation inductance of the integrated magnetic component The method meets the following conditions: In the formula, 、、 Air gaps on the first side column, the middle column and the second side column respectively; 、、 the magnetic resistances of the first side column, the middle column and the second side column are respectively determined by the respective air gap length and the magnetic path sectional area, and the relation is satisfied: In the formula, 、 And The lengths of air gaps on the first side column, the middle column and the second side column are respectively; 、 And The magnetic circuit sectional areas of the first side column, the middle column and the second side column are respectively; is vacuum magnetic permeability.
4. A hybrid winding based integrated magnetic component as claimed in claim 3, wherein the resonant inductance of the integrated magnetic component The method meets the following conditions: 。
5. a method for designing an integrated magnetic component based on a hybrid winding, comprising the steps of: Step S1, determining electrical parameters according to an application scene to obtain a transformer turns ratio, a target excitation inductance value and a target resonance inductance value; s2, selecting a magnetic core material and a magnetic core model; s3, determining magnetic path sectional areas of the first side column, the second side column and the middle column based on the target excitation inductance value and the target resonance inductance value; S4, designing wire diameters, turns and arrangement modes of a primary winding and a secondary winding and air gap lengths of a first side column, a second side column and a middle column based on the determined magnetic circuit cross section area and air gap length and combining a transformer turn ratio and a target excitation inductance value, wherein the primary winding is wound by Litz wires, and the secondary winding is a planar PCB winding; step S5, verifying the deviation between the actual excitation inductance and the target excitation inductance value and the deviation between the actual resonance inductance and the target resonance inductance value, and if the deviation exceeds a preset range, adjusting the air gap length of each magnetic column; Step S6, verifying the maximum magnetic flux density, if the maximum magnetic flux density exceeds the saturation magnetic flux density of the magnetic material, returning to the step S3 to adjust the magnetic path cross section, and if the maximum magnetic flux density meets the requirement, forming a complete integrated magnetic element design scheme; the leakage inductance value of the integrated magnetic element is configured to be the resonance inductance value required by the LLC resonant converter by adjusting the air gap lengths of the first side column, the second side column and the middle column and the turn number distribution of the primary winding on each magnetic column, so that the magnetic integration of the transformer and the resonance inductance is realized.
6. The method according to claim 5, wherein the electrical parameters in the step S1 include resonant frequency, input voltage, output voltage, and power specification of the LLC resonant converter, the transformer turns ratio is set according to the input voltage and the output voltage, and the target excitation inductance value and the target resonance inductance value are determined according to the resonant frequency, the power specification, and the soft switching condition.
7. The method of claim 5, wherein in step S4, the number of turns of the primary winding and the secondary winding is set according to a transformer turns ratio, and the air gap length of the center post is calculated and determined according to a target excitation inductance value and is cooperatively optimized with the air gap lengths of the first side post and the second side post so as to simultaneously satisfy the target excitation inductance value and the target resonance inductance value.
8. The method according to claim 5, wherein the predetermined range in step S5 is that the deviation between the actual inductance value and the target inductance value is not more than 5%.
9. The method of claim 5, wherein the first leg and the second leg have equal magnetic circuit cross-sectional areas and equal air gap lengths, and the number of turns of the primary winding on the first leg is equal to the number of turns on the second leg.
10. The method of claim 5, wherein verifying the maximum magnetic flux density in step S6 comprises simulating the maximum magnetic flux density at each location of the core under the maximum operating current or worst operating conditions and determining if the maximum magnetic flux density exceeds the saturation magnetic flux density of the selected magnetic material.

Description

Integrated magnetic element based on hybrid winding and design method Technical Field The invention relates to the technical field of power electronics, in particular to an integrated magnetic element based on a hybrid winding and a design method thereof, which are particularly suitable for LLC resonant converters. Background By virtue of the characteristic that the LLC resonant converter can realize zero-voltage switching in a full-load range, the switching loss can be obviously reduced, the energy conversion efficiency can be improved, and the LLC resonant converter is widely applied to scenes with high requirements on energy efficiency and power density, such as high-frequency power supplies, fast charging adapters and the like. In a typical LLC resonant converter topology, a resonant inductor is connected in series with a transformer, which together form the core component of the resonant cavity, wherein the resonant inductor is used to regulate the resonant frequency, optimize energy transfer and maintain soft switching characteristics, and the transformer effects voltage conversion and electrical isolation. The accurate matching of the resonant inductance and the parameters of the transformer is the premise of the efficient and stable operation of the LLC converter. Along with the continuous promotion of power supply equipment miniaturization, integration demand, planar transformer possesses small, high low, the orderly advantage of overall arrangement owing to adopting PCB winding and slim magnetic core integrated configuration, becomes the mainstream selection of LLC converter gradually. However, the following technical problems exist in the practical application of the existing planar transformer: First, high frequency loss is large. When the number of primary turns is large, the planar transformer needs to stack a plurality of layers of PCB copper foils to achieve the required number of turns, and the plurality of layers of copper foils can generate obvious skin effect and proximity effect under high frequency, so that winding alternating current loss is increased sharply, and improvement of the efficiency of the converter is restricted. Secondly, the degree of freedom of winding design is low. The turns and the layout of the PCB winding are solidified once the PCB winding is made, so that the PCB winding is difficult to flexibly adjust and cannot adapt to the different requirements of different application scenes on the turns and the inductance. Thirdly, leakage inductance is difficult to adjust. The primary winding and the secondary winding of the planar transformer are tightly coupled, so that high coupling coefficient and low leakage inductance can be easily realized, however, the low leakage inductance characteristic makes the leakage inductance and excitation inductance of the planar transformer difficult to meet the specific requirement of LLC resonance working condition on resonance inductance, and therefore, independent resonance inductance needs to be additionally connected in series. Fourth, the power density is limited. For the above reasons, the existing planar transformer generally needs an additional series independent resonant inductor to meet the resonant requirement of the LLC converter, which not only increases the number of components, occupies additional circuit board space, but also introduces additional connection loss, and limits further improvement of the overall power density of the power supply. Disclosure of Invention The invention provides an integrated magnetic element based on a mixed winding, which aims to solve the problems of high winding loss, difficult leakage inductance adjustment and limited power density caused by the need of externally connecting independent resonant inductance of the traditional planar transformer in the high-frequency and high-turn number application scene. In a first aspect, the present invention provides an integrated magnetic component based on a hybrid winding, comprising: the magnetic core comprises a first side column, a second side column and a middle column positioned between the first side column and the second side column, wherein air gaps are formed in the first side column, the second side column and the middle column; The primary winding is wound by Litz wires and is respectively connected in series with the first side column, the second side column and the middle column; The secondary winding adopts a planar PCB winding, is only wound on the middle column, and has a winding direction opposite to that of the primary winding on the middle column; the leakage inductance value of the integrated magnetic element is configured to be the resonance inductance value required by the LLC resonant converter by adjusting the air gap lengths of the first side column, the second side column and the middle column and the turn number distribution of the primary winding on each magnetic column, so that the magnetic integration of the transform