Intelligent variable inductor and LLC resonant converter based on magnetorheological material

Abstract

A smart variable inductor based on magnetorheological materials comprises an "EE"-shaped iron core, two DC control coils, one AC coil, and a magnetorheological material gap. The magnetorheological material gap is located on the central column of the "EE"-shaped iron core. The two DC control coils and the AC coil are wound around the two side columns and the central column of the "EE"-shaped iron core, respectively. By controlling the DC current in the DC control coil, the magnetic saturation of the side columns can be changed, thus achieving intelligent wide-range adjustment of the inductance of the AC coil. The beneficial effects of this patent are: the provided smart variable inductor based on magnetorheological materials, due to the higher permeability of magnetorheological materials than air, which decreases with increasing magnetic field strength, has advantages such as a wide inductance adjustment range and low diffusion flux. When used in LLC resonant converters, it can achieve intelligent wide-range adjustment of input / output voltage and load, as well as intelligent current sharing control in multi-parallel converters.

Description

Technical Field

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

[0002] In recent years, switching power supplies that provide electrical energy to various electrical equipment are developing in the direction of low voltage, high current, small size, light weight, high efficiency, thinness and integration, including voltage adjustment modules that provide precision power for high-precision and high-speed microprocessors such as the computer's central processing unit (CPU) and digital signal processor (DSP), 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 regulation power supplies, aviation power supplies, new energy power generation and superconducting energy storage. These switching power supplies adopt the topology of resonant converters, especially LLC resonant converters and LCC resonant converters, to achieve zero voltage switching (ZVS) of the primary side switch tube and zero current switching (ZCS) of the secondary side switch tube, and 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 main problems: First, LLC resonant converters use the method of adjusting the switching frequency to adjust the voltage gain and achieve output voltage and load regulation. However, when the input / output voltage variation range and the load variation range are wide, the switching frequency variation range also becomes wider, causing the switching frequency of the LLC resonant converter to deviate from the resonant frequency, and soft switching cannot be achieved, the switching loss increases, and the resonant inductor and resonant transformer are difficult to optimize due to the wide frequency band; second, in order to expand the capacity, LLC resonant converters often require multi-phase parallel operation. However, due to the deviation between the resonant tank parameters (including resonant inductance, resonant capacitance, and excitation inductance) of each parallel phase (usually within the range of ±5%), the resonant current and rectifier current of each parallel phase are unbalanced, which reduces efficiency and can damage the circuit in severe cases.

[0004] In order to solve these two problems, people have studied variable inductors and variable excitation inductance transformers, which are used as resonant inductors and resonant transformers for LLC resonant converters. The switching frequency of the LLC resonant converter is fixed at the resonant frequency. By adjusting the inductance value of the variable inductor or the excitation inductance value of the variable excitation inductance transformer, the voltage gain of the LLC resonant converter is adjusted to achieve wide range adjustment of the input voltage, output voltage and load of the LLC resonant converter. However, the core magnetic column of the traditional variable inductor and variable excitation inductance transformer adopts air gap, which leads to a relatively narrow adjustment range of the inductance value, and a small adjustment range of the input\output voltage and load of the LLC resonant converter. Summary of the invention

[0005] The object of the present invention is to overcome the above technical deficiencies and provide an intelligent variable inductor based on magnetorheological material, which is used as a variable resonant inductor of resonant converters such as LLC resonant converters and LCC resonant converters, and fixes the switching frequency of the LLC resonant converter at the resonant frequency or 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 realizing 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 and more than two-phase 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, consisting of a pair of "EE" shaped iron cores, a magnetorheological material gap, two DC control coils and an AC working coil; there is a magnetorheological material gap on the middle column of the "EE" shaped iron core; the material of the magnetorheological material gap is selected from one of the four magnetorheological materials of magnetorheological elastomer, magnetorheological plastic, magnetorheological fluid and magnetorheological glue.

[0008] The magnetization curve of the magnetorheological material gap is compared 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 is higher and higher than the magnetic permeability of the air gap.

[0009] The two DC control coils are respectively wound on the two side magnetic columns 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 two side magnetic columns and the yoke 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 two side magnetic columns of the "EE" shaped iron core respectively; by adjusting the size of the DC control current, the size of the DC magnetic flux can be controlled, the magnetic saturation degree of the side columns can be adjusted, the magnetic permeability of the two side magnetic columns can be changed, and a wide range adjustment of the inductance of the AC working coil can be achieved.

[0010] The AC working magnetic flux generated by the AC working current passes through the gap of the magnetorheological material; the magnetic permeability of the gap of the magnetorheological material is higher than that of air and decreases with the increase of the AC working current, thereby realizing intelligent wide-range adjustment of the inductance of the AC working coil and reducing the diffusion magnetic flux of the gap of the magnetorheological material.

[0011] The intelligent variable inductor based on magnetorheological material is used as the resonant inductor of the LLC resonant converter, and the magnitude of the DC control current of the intelligent variable inductor based on magnetorheological material is adjusted to achieve intelligent wide-range adjustment of the inductance value of the AC working coil of the intelligent variable inductor, thereby fixing the switching frequency of the switch tube of the LLC resonant converter at the resonant frequency, or fixed in a very small range near the resonant frequency, to achieve intelligent wide-range adjustment of the voltage gain of the LLC resonant converter, and used for intelligent wide-range adjustment of the input voltage, output voltage and load of the LLC resonant converter.

[0012] 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 inductor based on magnetorheological material is used in the LLC resonant converter with the circuit topology structure to achieve intelligent wide-range adjustment of the voltage gain of the LLC resonant converter with the circuit topology structure, and is used to achieve 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.

[0013] The beneficial effects of the present invention are:

[0014] The intelligent variable inductor and LLC resonant converter based on magnetorheological material provided by the present invention change the magnetic induction intensity of the intelligent variable inductor core and the magnetorheological material by adjusting the current value of the DC control coil of the intelligent variable inductor based on magnetorheological material, so that the inductance value thereof increases first and then decreases with the magnetic induction intensity, thereby fixing the switching frequency of the LLC resonant converter at the resonant frequency, or fixing it in a very small range near the resonant frequency, and performing intelligent wide-range adjustment of the voltage gain of the LLC resonant converter, realizing intelligent wide-range adjustment of the voltage gain, input voltage, output voltage and load of the LLC resonant converter, and current balancing control of two-phase and more than two-phase parallel LLC resonant converters (two-phase resonant currents have the same phase or are staggered by 180°, especially staggered by 90°); in addition, since the magnetic permeability of the magnetorheological material is higher than that of air, the air gap edge flux generated is smaller, which reduces the eddy current loss of the winding near the air gap on the one hand, and reduces the leakage magnetic field and electromagnetic interference on the other hand.

[0015] The following is a specific description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural front view of an intelligent variable inductor based on magnetorheological material provided in Example 1 of this patent.

[0017] Figure 1a Is for Figure 1 A structural front view of an "EE" shaped core with an air gap in the center column is provided.

[0018] Figure 1b Is for Figure 1 Provided for filling Figure 1a Schematic diagram of a magnetorheological material in the air gap of the "EE" shaped iron core.

[0019] Figure 1c yes Figure 1a The air gap in the middle column of the "EE" shaped core is filled Figure 1b Front view of the structure behind the magnetorheological material shown.

[0020] Figure 1d yes Figure 1b Magnetization curves of magnetorheological material and air are shown.

[0021] Figure 1e yes Figure 1 The magnetic flux flow diagram of the smart variable inductor based on magnetorheological material is shown.

[0022] 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.

[0023] Figure 1g The resonant inductor of the half-bridge LLC resonant converter adopts Figure 1 The circuit topology diagram of the smart variable inductor based on magnetorheological material is shown.

[0024] Figure 1h yes Figure 1g The adoption shown Figure 1 The smart variable inductor based on magnetorheological material and Figure 1a Voltage gain diagram of the half-bridge LLC resonant converter with air-gap variable inductor shown.

[0025] Figure 2 This is the structural front view of an intelligent variable excitation inductance transformer based on magnetorheological material provided in Example 2 of this patent.

[0026] 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 material is shown.

[0027] Figure 3 The resonant inductor and resonant transformer of the half-bridge LLC resonant converter provided in the third embodiment of the present invention 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 material is shown.

[0028] In the figure, 1-"EE" shaped iron core; 2-two side magnetic columns (side columns) of the "EE" shaped iron core 1; 3-middle column of the "EE" shaped iron core 1; 4-magnetic yoke of the "EE" shaped iron core 1; 5-air gap of the middle column 3 of the "EE" shaped iron core 1; 6-magnetorheological material; 7-magnetorheological material gap of the middle column 3 of the "EE" shaped iron core 1; N dc1 、N dc2 - Two DC control coils wound on the two side magnetic columns 2 of the "EE" shaped core; N ac1 、N ac2 - Two AC working coils wound on the middle column 3 of the "EE" shaped core;

[0029] V dc - Added to two DC control coils N in series dc1 、N dc2 The DC voltage on dc - Two DC control coils N in series dc1 、N dc2 The DC control current passing through dc -DC control current I dcThe 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 The AC working current passing through ac -AC working current i ac1 The AC working magnetic flux generated in the middle column 3 of the "EE" shaped iron core; Φ ac1 , Φ ac2 -AC working magnetic flux Φ ac The two side columns 2 of the "EE" shaped core are divided into two parts; i ac2 -AC working magnetic flux Φ ac In AC working coil N ac2 The AC working current induced in the

[0030] 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 -Smart variable inductor based on magnetorheological material; C r1 - resonant capacitor of LLC resonant converter; T1- resonant transformer of LLC resonant converter; L m1 - magnetizing inductance of resonant transformer T1; T MR -Intelligent variable excitation inductance transformer based on magnetorheological materials; L m1_MR -Intelligent variable excitation inductance transformer based on magnetorheological material T 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;

[0031] V ref -The given DC voltage of the control system of the LLC resonant converter; ΔV = V ref -V o -LLC resonant converter control system with given DC voltage V ref With the output DC voltage V o Deviation of feedback value; PI regulator - proportional integral regulator; V con - The DC control voltage output by the PI regulator. DETAILED DESCRIPTION

[0032] Below in conjunction with the drawings and Examples, the specific embodiments of the present invention are further described in detail. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present 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.

[0033] Embodiment 1:

[0034] Refer to the attached Figure 1 , an intelligent variable inductor based on magnetorheological material, comprising 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 core; refer to the attached Figure 1b , 1c , the magnetorheological material 6 is filled at the position of the air gap 5 to form the magnetorheological material gap 7; the material of the magnetorheological material gap 7 is selected from one of four magnetorheological materials such as magnetorheological elastomer, magnetorheological plastic, magnetorheological fluid, and magnetorheological glue;

[0035] 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 value of the magnetic field intensity H is ±500 kA / m, as the absolute value of the magnetic field intensity H decreases, the slope of the magnetization curve of the magnetorheological material 6 becomes larger and larger, that is, the magnetic permeability of the magnetorheological material gap 7 is higher and higher than the magnetic permeability of the air gap 5.

[0036] 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 respectively. 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. dc In the AC working coil N ac1 The AC working current i ac1 , an AC working magnetic flux Φ is generated in the middle column of the "EE" shaped core ac, the AC working magnetic flux Φ ac Divide into two: Φ 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 AC working coil 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 ac1 The inductance L MR Wide range adjustment;

[0037] Refer to the attached Figure 1e , the AC working current i ac1 The AC working magnetic flux Φ generated 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 Induced eddy current loss in the medium reduces electromagnetic interference;

[0038] 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 The DC control current I dc Refer to the attached Figure 1f , realizing the intelligent variable inductor L MR The inductance value of the LLC resonant converter is intelligently adjusted over a wide range, thereby fixing 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; see the attached Figure 1h , realizing intelligent wide range adjustment of the voltage gain of the LLC resonant converter, for additional Figure 1g The input voltage V of the single-phase half-bridge LLC resonant converter is shown in , output voltage V o and load R L Intelligent wide range adjustment;

[0039] Refer to the attached Figure 1f , attached Figure 1gThe 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;

[0040] 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 only from 10 to 30uH. Figure 1h , the LLC resonant converter adopts the air gap variable inductor, and the voltage gain variation range is only 1.32-1.23=0.09;

[0041] Attached 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 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.

[0042] Embodiment 2:

[0043] 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 ac1 The AC working voltage is applied to both ends of 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 Φ ac One is divided into two, passing through the magnetic columns 2 on both sides of the "EE"-shaped iron core respectively;

[0044] 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 ac1 The excitation inductance L m1_MR Wide range adjustment;

[0045] flows through the primary winding N ac1 The primary AC working current i ac1 The AC working magnetic flux Φ generated ac The magnetorheological material gap 7 has a higher magnetic permeability than air and flows along with the primary AC working current i ac1 The increase of the primary winding N ac1 The excitation inductance L m1_MR Intelligent wide range regulation and reducing the diffusion flux of magnetorheological material gap 7;

[0046] 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 is used to adjust 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 regulation is implemented to fix 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 the voltage gain of the LLC resonant converter is intelligently adjusted over a wide range to achieve the input voltage V in , output voltage V o and load R L Intelligent wide range control;

[0047] 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 MR A resonant transformer for the LLC resonant converter of the circuit topology structure is used to realize intelligent wide-range adjustment of the voltage gain of the LLC resonant converter of the circuit topology structure, and 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.

[0048] Embodiment three:

[0049] See 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 in the LLC resonant converter r1 and resonant transformer T1.

[0050] Embodiment 4:

[0051] 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 given DC output voltage V of the LLC resonant converter ref The detected DC output voltage V o Deviation ΔV=V ref -V o After proportional integral (PI) regulation, the DC control voltage V is obtained. con , the voltage controlled current source outputs a DC voltage V dc , get the DC control current I dc , pass into 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 flows through Lr1 , to achieve the resonant inductance L of the LLC resonant converter r1Intelligent 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 or more parallel LLC resonant converters.

[0052] Finally, it should be noted that the above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. The above multiple embodiments are used in this specification to describe the principles and implementation methods of the present invention, which are only used to help understand the methods and core ideas of the present invention; at the same time, for those skilled in the art, the specific implementation methods and application scopes may be changed according to the ideas of the present invention. Therefore, the content of this specification should not be understood as a limitation on the present invention, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. An intelligent variable inductor and LLC resonant converter based on magnetorheological material, characterized in that: It is composed of a pair of "EE" shaped iron cores, a magnetorheological material gap, two DC control coils and an AC working coil; there is a magnetorheological material gap on the middle column of the "EE" shaped iron core; the material of the magnetorheological material gap is selected from one of the four magnetorheological materials of magnetorheological elastomer, magnetorheological plastic, magnetorheological fluid and magnetorheological glue; The magnetization curve of the magnetorheological material gap is compared 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 is 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 the magnetic 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 size of the DC control current, the size 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 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 of the magnetorheological material; the magnetic permeability of the gap of the magnetorheological material is higher than that of air, and decreases with the increase of the AC working current, thereby realizing the intelligent wide-range adjustment of the inductance of the AC working coil and reducing the diffusion magnetic flux of the gap of the magnetorheological material; The intelligent variable inductor based on magnetorheological material is used as the resonant inductor of the LLC resonant converter, and the magnitude of the DC control current of the intelligent variable inductor based on magnetorheological material is adjusted to achieve intelligent wide-range adjustment of the inductance value of the AC working coil of the intelligent variable inductor, thereby fixing the switching frequency of the switch tube of the LLC resonant converter at the resonant frequency, or near the resonant frequency, to achieve intelligent wide-range adjustment of the voltage gain of the LLC resonant converter, and to be 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 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 achieve intelligent wide-range adjustment of the voltage gain of the LLC resonant converter with the circuit topology structure, and is used to achieve 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 and LLC resonant converter based on magnetorheological material according to claim 1, characterized in that: An AC working coil is added to the middle column of the "EE" shaped iron core, and there are two AC working coils in total, including the original AC working coil, to form an intelligent variable excitation inductance transformer based on magnetorheological material, and the two AC working coils are respectively used as the primary and secondary windings of the intelligent variable excitation inductance transformer; an AC working voltage is applied to both ends of the primary winding to generate a primary AC working current, and an AC working magnetic flux is generated in the middle column of the "EE" shaped iron core. The AC working magnetic flux generates an induced potential on the secondary winding, and outputs a secondary AC working current for the load; the AC working magnetic flux is divided into two, passing 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 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 with the increase of the primary AC working current, thereby realizing intelligent wide-range adjustment of the excitation inductance of the primary winding and reducing the diffusion magnetic flux of 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 realize the 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 switch tube of the LLC resonant converter at the resonant frequency, or fixing it near the resonant frequency, and performing the intelligent wide-range adjustment of the voltage gain of the LLC resonant converter, thereby realizing the intelligent wide-range control of the input voltage, output voltage and load of the 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 of the circuit topology structure, so as to realize the intelligent wide-range adjustment of the voltage gain of the LLC resonant converter of the circuit topology structure, and is used to realize the intelligent wide-range control of the voltage gain, input voltage, output voltage and load of the LLC resonant converter of the circuit topology structure, as well as the current sharing control of two-phase and more parallel LLC resonant converters.

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

4. The intelligent variable inductor and LLC resonant converter 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 adjustment to obtain a DC control voltage. The DC control current is obtained by voltage-controlled current source and 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 or more parallel LLC resonant converters.

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