Intelligent variable inductor based on magnetorheological material and LLC resonant converter

Abstract

An intelligent variable inductor based on a magnetorheological material is composed of a pair of EE-shaped iron cores, two direct current control coils, an alternating current coil and a magnetorheological material gap. A magnetorheological material gap is formed in a middle column of the EE-shaped iron core, and the two direct-current control coils and the alternating-current coil are wound on two side columns and the middle column of the EE-shaped iron core respectively. The value of the direct-current control current is adjusted through the direct-current control current in the direct-current control coil, the magnetic saturation degree of the side column can be changed, and intelligent wide-range adjustment of the inductance value of the alternating-current coil is achieved. The intelligent variable inductor based on the magnetorheological material has the beneficial effects that the magnetic conductivity of the magnetorheological material is higher than that of air and is reduced along with increase of the magnetic field intensity, so that the intelligent variable inductor has the advantages of being wide in inductance value adjusting range, small in diffusion flux and the like, and is used for an LLC resonant converter; the intelligent wide-range adjustment of the input / output voltage and the load and the intelligent current-sharing control of the multi-path parallel converter can be realized.

Description

Technical Field

[0001] The present invention relates to the fields of magnetorheological materials, inductors and transformers, in particular to an intelligent variable inductor and LLC resonant converter based on magnetorheological materials. Background Art

[0002] In recent years, switching power supplies that provide electrical energy to various electrical devices are developing towards low voltage, high current, small size, light weight, high efficiency, thinness and integration. These include voltage regulation modules that provide precision power for high-precision, high-speed microprocessors such as computer central processing units (CPUs) and digital signal processors (DSPs), as well as switching power supplies that have emerged in recent years and are widely used in large data center server power supplies, new energy vehicles and charging piles, hybrid vehicles, uninterruptible power supplies, power quality conditioning power supplies, aviation power supplies, new energy power generation and superconducting energy storage. These switching power supplies adopt the topology of resonant converters, especially resonant converters such as LLC resonant converters and LCC resonant converters, to achieve zero voltage turn-on (ZVS) of the primary side switch tube and zero current turn-off (ZCS) of the secondary side switch tube of their transformers. They have the advantages of low switching loss, low switching stress, high efficiency and high power density. Therefore, resonant converters such as LLC resonant converters and LCC resonant converters have been widely used in the above-mentioned fields.

[0003] Conventional LLC resonant converters face two major problems: First, LLC resonant converters use switching frequency to adjust voltage gain and achieve output voltage and load regulation. However, when the input / output voltage and load variation ranges are wide, the switching frequency variation range also widens, causing the LLC resonant converter's switching frequency to deviate from the resonant frequency, making soft switching impossible. This increases switching losses and makes it difficult to optimize the design of the resonant inductor and resonant transformer due to the wide frequency band. Second, to expand capacity, LLC resonant converters often require multi-phase parallel operation. However, due to deviations (usually within the range of ±5%) between the resonant tank parameters (including resonant inductance, resonant capacitance, and excitation inductance) of each parallel phase, the resonant current and rectifier current of each parallel phase are unbalanced, reducing efficiency and, in severe cases, damaging the circuit.

[0004] To address these two issues, researchers have studied variable inductors and variable excitation inductance transformers. These are used as resonant inductors and resonant transformers in LLC resonant converters. By fixing the LLC resonant converter's switching frequency at the resonant frequency, the LLC resonant converter's voltage gain can be adjusted by adjusting the inductance of the variable inductor or the excitation inductance of the variable excitation inductance transformer, enabling wide-range regulation of the LLC resonant converter's input voltage, output voltage, and load. However, the use of air gaps in the core magnetic columns of conventional variable inductors and variable excitation inductance transformers results in a relatively narrow inductance adjustment range, limiting the LLC resonant converter's input / output voltage and load adjustment ranges. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned technical deficiencies and provide an intelligent variable inductor based on magnetorheological material for use as a variable resonant inductor in resonant converters such as LLC resonant converters and LCC resonant converters. The switching frequency of the LLC resonant converter is fixed at the resonant frequency or within a very small range near the resonant frequency. By adjusting the current of the DC control winding of the intelligent variable inductor based on magnetorheological material, the inductance value of the intelligent variable resonant inductor can be intelligently adjusted over a wide range, thereby achieving intelligent wide-range adjustment of the input voltage, output voltage, and load of the LLC resonant converter, as well as current sharing control of two-phase or more parallel LLC resonant converters.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] An intelligent variable inductor and LLC resonant converter based on magnetorheological material are provided. The air gap on the core magnetic column of a conventional variable inductor is filled with magnetorheological material to form an intelligent variable inductor based on magnetorheological material. The intelligent variable inductor based on magnetorheological material is used as the resonant inductor of the LLC resonant converter. When the switching frequency of the LLC resonant converter is fixed at the resonant frequency, or within a very small range near the resonant frequency, the resonant inductance value of the LLC resonant converter is intelligently and widely adjusted by adjusting the current value of the DC control coil of the intelligent variable inductor based on magnetorheological material, thereby achieving intelligent and wide-range adjustment of the voltage gain, input voltage, output voltage, and load of the LLC resonant converter, as well as current sharing control of two-phase or more parallel LLC resonant converters.

[0008] The beneficial effects of the present invention are:

[0009] The intelligent variable inductor and LLC resonant converter based on magnetorheological material provided by the present invention adjust the current value of the DC control coil of the intelligent variable inductor based on magnetorheological material to change the magnetic induction intensity of the intelligent variable inductor core and the magnetorheological material, so that the inductance value first increases and then decreases with the magnetic induction intensity. This fixes the switching frequency of the LLC resonant converter at the resonant frequency, or within a very small range near the resonant frequency, and performs intelligent wide-range adjustment of the LLC resonant converter's voltage gain. This achieves intelligent wide-range adjustment of the LLC resonant converter's voltage gain, input voltage, output voltage, and load, as well as current balancing control of two-phase and more-phase parallel LLC resonant converters (two-phase resonant currents are in phase or staggered by 180 degrees, especially staggered by 90 degrees). In addition, because the magnetorheological material has a higher magnetic permeability than air, the generated air gap edge flux is smaller, which reduces eddy current losses in the winding near the air gap and reduces leakage magnetic fields and electromagnetic interference.

[0010] The following is a detailed description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a structural front view of an intelligent variable inductor based on magnetorheological material provided in the first embodiment of the present invention.

[0012] Figure 1a It is for Figure 1 The structural front view of the "EE" shaped core with an air gap in the center column is provided.

[0013] Figure 1b It is for Figure 1 Provided for filling Figure 1a Schematic diagram of a magnetorheological material with an air gap in the "EE" shaped iron core.

[0014] Figure 1c yes Figure 1a The air gap in the center column of the "EE" shaped core is filled Figure 1b Front view of the structure behind the magnetorheological material shown.

[0015] Figure 1d yes Figure 1b Magnetization curves of magnetorheological material and air are shown.

[0016] Figure 1e yes Figure 1 The magnetic flux flow diagram of the smart variable inductor based on magnetorheological material is shown.

[0017] Figure 1f yes Figure 1 The smart variable inductor based on magnetorheological material and Figure 1a The inductance value variation range of the air gap variable inductor is shown in the figure.

[0018] Figure 1g The resonant inductor of the half-bridge LLC resonant converter adopts Figure 1 The circuit topology of the smart variable inductor based on magnetorheological material is shown.

[0019] Figure 1h yes Figure 1g The adoption shown Figure 1 The smart variable inductor based on magnetorheological materials and Figure 1a Voltage gain diagram of the half-bridge LLC resonant converter with air-gap variable inductor shown.

[0020] Figure 2 This is the structural main view of an intelligent variable excitation inductance transformer based on magnetorheological material provided in Example 2 of this patent.

[0021] Figure 2a The resonant transformer of the half-bridge LLC resonant converter adopts Figure 2 The circuit topology diagram of the intelligent variable excitation inductance transformer based on magnetorheological materials is shown.

[0022] Figure 3 The resonant inductor and resonant transformer of the half-bridge LLC resonant converter provided in the third embodiment of this patent adopt Figure 1 The smart variable inductor based on magnetorheological material and Figure 2 The circuit topology diagram of the intelligent variable excitation inductance transformer based on magnetorheological materials is shown.

[0023] Figure 4 This is a control system diagram of an LLC resonant converter using an intelligent variable inductor based on magnetorheological material, provided in Example 4 of this patent.

[0024] In the figure, 1 is an "EE"-shaped iron core; 2 is a magnetic column (side column) on both sides of the "EE"-shaped iron core 1; 3 is a center column of the "EE"-shaped iron core 1; 4 is a magnetic yoke of the "EE"-shaped iron core 1; 5 is an air gap of the center column 3 of the "EE"-shaped iron core 1; 6 is a magnetorheological material; 7 is a magnetorheological material gap of the center column 3 of the "EE"-shaped iron core 1; N dc1 、N dc2 - Two DC control coils wound on the magnetic columns 2 on both sides of the "EE" shaped iron core; N ac1 、N ac2 - Two AC working coils wound on the middle column 3 of the "EE" shaped core;

[0025] V dc - Added to two DC control coils N in series dc1 、N dc2 DC voltage on the dc- Two DC control coils N in series dc1 、N dc2 The DC control current passing through dc -DC control current I dc The DC magnetic flux generated in the magnetic columns 2 on both sides of the "EE" shaped core; i ac1 - In AC working coil N ac1 AC working current passing through; Ф ac -AC working current i ac1 The AC working magnetic flux generated in the middle column 3 of the "EE" shaped iron core; Ф ac1 , Ф ac2 -AC working magnetic flux Ф ac The two side columns 2 on both sides of the "EE" shaped core are divided into two parts; i ac2 -AC working magnetic flux Ф ac In the AC working coil N ac2 AC working current induced in the

[0026] V in 、V o -DC input voltage and DC output voltage of LLC resonant converter; Q1, Q2 - power electronic switching devices on the primary side of LLC resonant converter; L r1 - resonant inductor of LLC resonant converter; L MR -Intelligent variable inductor based on magnetorheological materials; C r1 - resonant capacitor of LLC resonant converter; T1- resonant transformer of LLC resonant converter; L m1 - the magnetizing inductance of the resonant transformer T1; T MR -Intelligent variable excitation inductance transformer based on magnetorheological materials; L m1_MR -Intelligent variable excitation inductance transformer T based on magnetorheological materials MR Intelligent variable excitation inductor; D1, D2-LLC resonant converter connected to the secondary winding of the resonant transformer T1 rectifier diode; C o -DC output filter capacitor of LLC resonant converter; R L -Load resistance of LLC resonant converter; i Lr1 - Flows through the resonant inductor L r1 The resonant current i D1 - rectified current flowing through the secondary winding of the resonant transformer T1;

[0027] V ref - Given DC voltage of the control system of LLC resonant converter; ΔV = V ref -V o -LLC resonant converter control system given DC voltage V ref and the output DC voltage Vo Deviation of feedback value; PI regulator - proportional integral regulator; V con - The DC control voltage output by the PI regulator. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the invention. In order to fully understand the present invention, many specific details are mentioned in the following detailed description, but those skilled in the art should understand that the present invention can be implemented without these specific details.

[0029] Example 1:

[0030] Refer to the attached Figure 1 , an intelligent variable inductor based on magnetorheological material, consisting of a pair of "EE" shaped iron core 1, a magnetorheological material gap 7, two DC control coils N dc1 、N dc2 and an AC working coil N ac1 Composition; see attached Figure 1a There is an air gap 5 on the middle column 3 of the "EE" shaped iron core; refer to the attached Figure 1b 、 1c , the position of the air gap 5 is filled with magnetorheological material 6 to form the magnetorheological material gap 7; the material of the magnetorheological material gap 7 is selected from one of the four magnetorheological materials such as magnetorheological elastomer, magnetorheological plastic, magnetorheological fluid, and magnetorheological glue;

[0031] Refer to the attached Figure 1d ,Will Figure 1c The magnetization curve of the magnetorheological material gap 7 is compared with the magnetization curve of the air gap 5. When the magnetic field strength H is within ±500 kA / m, as the absolute value of the magnetic field strength H decreases, the slope of the magnetization curve of the magnetorheological material 6 becomes increasingly larger, that is, the magnetic permeability of the magnetorheological material gap 7 becomes increasingly higher than that of the air gap 5.

[0032] Refer to the attached Figure 1 、 1e , the two DC control coils N dc1 、N dc2 The AC working coil N is wound on the two side magnetic columns (side columns) 2 of the "EE" shaped iron core. ac1 Wound on the middle column 3 of the "EE" shaped iron core; the two DC control coils N dc1 、N dc2 in series and control the current I dc , a DC magnetic flux Φ is generated in the magnetic columns 2 and the yoke 4 on both sides of the "EE" shaped core dcIn the AC working coil N ac1 AC working current i ac1 , an AC working magnetic flux Φ is generated in the middle column of the "EE" shaped iron core ac , the AC working magnetic flux Φ ac Divide into two: Ф ac1 and Φ ac2 , respectively passing through the two side magnetic columns 2 of the "EE" shaped iron core; adjusting the DC control current I dc The size of the DC magnetic flux Φ can be controlled dc The size of the magnetic poles 2 on both sides is adjusted to adjust the magnetic saturation degree and change the magnetic permeability of the magnetic poles 2 on both sides to realize the AC working coil N ac1 The inductance L MR Wide range adjustment;

[0033] Refer to the attached Figure 1e , the AC working current i ac1 The generated AC working magnetic flux Ф ac Through the magnetorheological material gap 7; refer to the attached Figure 1d The magnetic permeability of the magnetorheological material gap 7 is higher than that of air, and as the DC control current I dc decreases with the increase of Figure 1f , realize the AC working coil N ac1 The inductance L MR1 Intelligent wide range adjustment, and reduce the diffusion flux of the magnetorheological material gap, reduce the AC working coil N ac1 Reduce eddy current loss induced by electromagnetic interference;

[0034] Refer to the attached Figure 1g , will be attached Figure 1 The intelligent variable inductor L based on magnetorheological material MR Resonant inductor L for single-phase half-bridge LLC resonant converter r1 , adjust the intelligent variable inductor L based on magnetorheological material MR DC control current I dc Refer to the attached Figure 1f , realize the intelligent variable inductor L MR The inductance value is adjusted intelligently over a wide range, thereby fixing the switching frequency of the switches Q1 and Q2 of the LLC resonant converter at the resonant frequency, or within a very small range near the resonant frequency; see the attached Figure 1h , realizing intelligent wide range adjustment of voltage gain of the LLC resonant converter, for additional Figure 1g The input voltage V of the single-phase half-bridge LLC resonant converter shown in in , output voltage V o and load R LIntelligent wide range adjustment;

[0035] Refer to the attached Figure 1f , attached Figure 1g The resonant inductor L of the single-phase half-bridge LLC resonant converter r1 Use attached Figure 1 The intelligent variable inductor L based on magnetorheological material MR , the smart variable inductor L MR The inductance value range is 20~70uH, refer to the attached Figure 1h , the voltage gain of the LLC resonant converter varies in a range of 1.32-1=0.32;

[0036] Refer to the attached Figure 1a , will be attached Figure 1 The magnetorheological material gap 7 of the magnetorheological material-based intelligent variable inductor is replaced by an air gap 5. Figure 1f The inductance value of the air gap variable inductor varies from 10 to 30uH. Figure 1h , the LLC resonant converter uses the air gap variable inductor, and the voltage gain variation range is only 1.32-1.23=0.09;

[0037] Attachment Figure 1 The intelligent variable inductor based on magnetorheological material can also be used as a resonant inductor of a single-phase full-bridge LLC resonant converter, a half-bridge LLC resonant converter with two or more phases connected in parallel, or a full-bridge LLC resonant converter, to achieve intelligent wide-range adjustment of the voltage gain of these LLC resonant converters, and to achieve an input voltage V in , output voltage V o and load R L Intelligent wide-range control and current sharing control of two-phase or more parallel LLC resonant converters.

[0038] Example 2:

[0039] Refer to the attached Figure 2 , an intelligent variable inductor based on magnetorheological material, an AC working coil N is added to the middle column of the "EE" shaped iron core described in Example 1 ac2 , including the original AC working coil N ac1 , a total of two AC working coils, forming an intelligent variable excitation inductance transformer T based on magnetorheological materials MR , the two AC working coils N ac1 、N ac2 As the intelligent variable excitation inductance transformer T MR The primary and secondary windings; in the primary winding N ac1The AC working voltage is applied to both ends of the circuit to generate the primary AC working current i ac1 , an AC working magnetic flux Φ is generated in the middle column 3 of the "EE" shaped iron core ac , the AC working magnetic flux Φ ac In the secondary winding N ac2 The induced potential is generated on the load, and the secondary AC working current i is output to the load. ac2 The AC working magnetic flux Ф ac One is divided into two, passing through the magnetic columns 2 on both sides of the "EE"-shaped iron core respectively;

[0040] Adjust the DC control current I dc The size of the DC magnetic flux Φ can be controlled dc The size of the primary winding N is adjusted to adjust the magnetic saturation degree of the magnetic columns 2 on both sides, change the magnetic permeability of the magnetic columns 2 on both sides, and realize the ac1 The excitation inductance L m1_MR Wide range adjustment;

[0041] flows through the primary winding N ac1 The primary AC working current i ac1 The generated AC working magnetic flux Ф ac The magnetorheological material gap 7 has a higher magnetic permeability than air and is connected to the primary AC working current i ac1 The increase of the primary winding N ac1 The excitation inductance L m1_MR Intelligent wide range adjustment and reduction of the diffusion flux of the magnetorheological material gap 7;

[0042] Refer to the attached Figure 2a , the intelligent variable excitation inductance transformer T based on magnetorheological material MR The resonant transformer T1 used for the LLC resonant converter adjusts the intelligent variable excitation inductance transformer T based on magnetorheological materials. MR The DC control winding current value I dc , realize the variable excitation inductance transformer T MR The primary winding N ac1 The excitation inductance value L m1_MR The intelligent wide range adjustment of the LLC resonant converter fixes the switching frequency of the switch tubes Q1 and Q2 of the LLC resonant converter at the resonant frequency, or in a very small range near the resonant frequency, and performs intelligent wide range adjustment of the voltage gain of the LLC resonant converter to achieve the input voltage V in , output voltage V o and load R L Intelligent wide range control;

[0043] The circuit topology of the LLC resonant converter can be a single-phase half-bridge LLC resonant converter, a single-phase full-bridge LLC resonant converter, a half-bridge LLC resonant converter with two or more phases in parallel, or a full-bridge LLC resonant converter; the intelligent variable excitation inductance transformer T based on magnetorheological material is connected to the LLC resonant converter. MR A resonant transformer for the LLC resonant converter of the circuit topology structure is used to achieve intelligent wide-range adjustment of the voltage gain of the LLC resonant converter of the circuit topology structure, and is used to achieve an input voltage V in , output voltage V o and load R L Intelligent wide-range control and current sharing control of two-phase and more than two-phase parallel LLC resonant converters.

[0044] Example 3:

[0045] Refer to the attached Figure 3 , the intelligent variable inductor L based on magnetorheological material described in the first embodiment MR The intelligent variable excitation inductance transformer T based on magnetorheological material described in the second embodiment M At the same time, the resonant inductor L used for the LLC resonant converter r1 and resonant transformer T1.

[0046] Example 4:

[0047] Refer to the attached Figure 4 , the intelligent variable inductor L based on magnetorheological material described in the first embodiment MR The resonant inductor L used for the LLC resonant converter r1 , the LLC resonant converter has a given DC output voltage V ref The detected DC output voltage V o Deviation ΔV=V ref -V o After proportional integral (PI) regulation, the DC control voltage V con , the voltage controlled current source outputs a DC voltage V dc , get the DC control current I dc , pass through the intelligent variable inductor L based on magnetorheological material MR Two DC control coils N connected in series dc1 and N dc2 When the LLC resonant converter is working, the intelligent variable inductor L based on magnetorheological material MR AC working coil N ac1 AC working current i Lr1 , realize the resonant inductance L of the LLC resonant converterr1 Intelligent wide range regulation, thereby achieving the voltage gain of the LLC resonant converter, input voltage V in , output voltage V o and load R L Intelligent wide-range regulation and current sharing control of two-phase and more than two-phase parallel LLC resonant converters.

[0048] Finally, it should be noted that the above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. This specification uses multiple embodiments to describe the principles and implementation methods of the present invention, which are intended only to help understand the methods and core concepts of the present invention. At the same time, those skilled in the art will appreciate that the specific implementation methods and scope of application may vary based on the concepts of the present invention. Therefore, the contents of this specification should not be construed as limiting the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An intelligent variable inductor based on magnetorheological material, characterized by: The device comprises an EE-shaped iron core, a magnetorheological material gap, two DC control coils, and an AC working coil; a magnetorheological material gap is provided on the center column of the EE-shaped iron core; the magnetorheological material gap is made of one of four magnetorheological materials: magnetorheological elastomer, magnetorheological plastic, magnetorheological fluid, or magnetorheological glue; Comparing the magnetization curve of the magnetorheological material gap with the magnetization curve of the air gap, when the magnetic field strength is within ±500 kA / m, as the absolute value of the magnetic field strength decreases, the slope of the magnetization curve of the magnetorheological material becomes larger and larger, that is, the magnetic permeability of the magnetorheological material gap becomes higher and higher than the magnetic permeability of the air gap; The two DC control coils are respectively wound on the magnetic columns on both sides of the "EE"-shaped iron core, and the AC working coil is wound on the middle column of the "EE"-shaped iron core; the two DC control coils are connected in series, and a DC control current is passed through the two DC control coils to generate a DC magnetic flux in the magnetic columns and yoke on both sides of the "EE"-shaped iron core; an AC working current is passed through the AC working coil to generate an AC working magnetic flux in the middle column of the "EE"-shaped iron core, and the AC working magnetic flux is divided into two and passes through the magnetic columns on both sides of the "EE"-shaped iron core respectively; by adjusting the magnitude of the DC control current, the magnitude of the DC magnetic flux can be controlled, the magnetic saturation degree of the side columns can be adjusted, the magnetic permeability of the magnetic columns on both sides can be changed, and a wide range adjustment of the inductance of the AC working coil can be achieved; The AC working magnetic flux generated by the AC working current passes through the gap in the magnetorheological material; the magnetic permeability of the gap in the magnetorheological material is higher than that of air and decreases with increasing AC working current, thereby achieving intelligent wide-range adjustment of the inductance of the AC working coil and reducing the diffusion magnetic flux in the gap in the magnetorheological material; The magnetorheological material-based intelligent variable inductor is used as the resonant inductor of an LLC resonant converter. By adjusting the magnitude of the DC control current of the magnetorheological material-based intelligent variable inductor, the inductance of the AC working coil of the intelligent variable inductor can be intelligently adjusted over a wide range. This fixes the switching frequency of the switching tube of the LLC resonant converter at the resonant frequency, or within a very small range near the resonant frequency, thereby achieving intelligent wide-range adjustment of the voltage gain of the LLC resonant converter and being used for intelligent wide-range adjustment of the input voltage, output voltage, and load of the LLC resonant converter. The circuit topology of the LLC resonant converter can be a single-phase half-bridge LLC resonant converter, a single-phase full-bridge LLC resonant converter, a half-bridge LLC resonant converter with two or more phases connected in parallel, or a full-bridge LLC resonant converter; the intelligent variable inductor based on magnetorheological material is used in the LLC resonant converter with the circuit topology structure to realize intelligent wide-range adjustment of the voltage gain of the LLC resonant converter with the circuit topology structure, and is used to realize intelligent wide-range control of the input voltage, output voltage and load of the LLC resonant converter with the circuit topology structure, as well as current sharing control of two-phase or more parallel LLC resonant converters.

2. The intelligent variable inductor based on magnetorheological material according to claim 1, characterized in that: An AC working coil is added to the center column of the "EE"-shaped iron core. Counting the original AC working coil, there are a total of two AC working coils, forming an intelligent variable excitation inductance transformer based on magnetorheological material. The two AC working coils serve as the primary and secondary windings of the intelligent variable excitation inductance transformer, respectively. An AC working voltage is applied to both ends of the primary winding to generate a primary AC working current, which generates an AC working magnetic flux in the center column of the "EE"-shaped iron core. The AC working magnetic flux generates an induced potential on the secondary winding, outputting a secondary AC working current to a load. The AC working magnetic flux is split into two, passing through the two side magnetic columns of the "EE"-shaped iron core respectively. By adjusting the magnitude of the DC control current, the magnitude of the DC magnetic flux can be controlled, the magnetic saturation degree of the magnetic columns on both sides can be adjusted, the magnetic permeability of the magnetic columns on both sides can be changed, and a wide range of adjustment of the excitation inductance of the primary winding can be achieved; The AC working magnetic flux generated by the primary AC working current flowing through the primary winding passes through the magnetorheological material gap. The magnetic permeability of the magnetorheological material gap is higher than that of air and decreases as the primary AC working current increases, thereby achieving intelligent wide-range adjustment of the excitation inductance of the primary winding and reducing the diffusion magnetic flux in the magnetorheological material gap. The intelligent variable excitation inductance transformer based on magnetorheological material is used as the resonant transformer of the LLC resonant converter, and the current value of the DC control winding of the intelligent variable excitation inductance transformer based on magnetorheological material is adjusted to achieve intelligent wide-range adjustment of the excitation inductance value of the primary winding of the variable excitation inductance transformer, thereby fixing the switching frequency of the switching tube of the LLC resonant converter at the resonant frequency, or within a very small range near the resonant frequency, and performing intelligent wide-range adjustment of the voltage gain of the LLC resonant converter, thereby achieving intelligent wide-range control of the input voltage, output voltage, and load of the LLC resonant converter; The circuit topology of the LLC resonant converter can be a single-phase half-bridge LLC resonant converter, a single-phase full-bridge LLC resonant converter, a half-bridge LLC resonant converter with two or more phases in parallel, or a full-bridge LLC resonant converter; the intelligent variable excitation inductance transformer based on magnetorheological material is used for the resonant transformer and its excitation inductance of the LLC resonant converter with the circuit topology structure, so as to realize intelligent wide-range adjustment of the voltage gain of the LLC resonant converter with the circuit topology structure, and to realize intelligent wide-range control of the voltage gain, input voltage, output voltage and load of the LLC resonant converter with the circuit topology structure, as well as current sharing control of two-phase or more parallel LLC resonant converters.

3. The intelligent variable excitation inductance transformer based on magnetorheological material according to claim 2, characterized in that: The intelligent variable inductor based on magnetorheological material and the intelligent variable excitation inductance transformer are simultaneously used as the resonant inductor and resonant transformer of the LLC resonant converter.

4. The intelligent variable inductor based on magnetorheological material according to claim 1, characterized in that: The intelligent variable inductor based on magnetorheological material is used as the resonant inductor of the LLC resonant converter. The deviation between the given DC output voltage of the LLC resonant converter and the detected DC output voltage is adjusted by proportional integral (PI) to obtain a DC control voltage. The DC control current is obtained by passing through a voltage-controlled current source and is passed into two series-connected DC control coils of the intelligent variable inductor based on magnetorheological material. When the LLC resonant converter is working, the AC working coil of the intelligent variable inductor based on magnetorheological material flows through the AC working current, thereby realizing intelligent wide-range adjustment of the resonant inductance of the LLC resonant converter, thereby realizing intelligent wide-range adjustment of the voltage gain, input voltage, output voltage and load of the LLC resonant converter, as well as intelligent wide-range adjustment of current sharing control and voltage gain of two-phase and more parallel LLC resonant converters.

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