Spacecraft power filter based on common-differential-mode three-dimensional integrated inductors and method of manufacture

Abstract

The application relates to a space navigation power supply filter based on a common-difference-mode three-dimensional integrated inductor and a manufacturing method, wherein the common-difference-mode three-dimensional integrated inductor is composed of a double-column magnetic core, a matched magnetic core and an LTCC substrate; the LTCC substrate is provided with four hollow areas; the double-column magnetic core is provided with two middle columns and two side columns; the double-column magnetic core and the matched magnetic core are inserted into the hollow areas of the LTCC substrate and fixed, a common-mode inductor is formed by the two middle columns, the LTCC substrate and the matched magnetic core, and a differential-mode inductor is formed by the two side columns, the LTCC substrate and the matched magnetic core; the inside of the LTCC substrate is printed with a common-mode capacitor and a multilayer inductor winding; the front surface of the LTCC substrate is welded with a differential-mode capacitor, and the double-column magnetic core and the matched magnetic core realize all functions of the power supply filter; the back surface of the LTCC substrate is welded with BGA soldering balls / PGA soldering pins; and the LTCC substrate, a surrounding frame and a cover plate form a sealed power supply filter cavity structure.

Description

TECHNICAL FIELD

[0001] The application relates to a high-density aerospace power supply filter based on a common-differential-mode three-dimensional integrated inductor and a manufacturing method, which is suitable for a power supply input filter product in the field of aerospace secondary power supply, and can be popularized and applied to high-density filters and secondary power supply products with large current characteristics in the military and civilian fields. BACKGROUND

[0002] In order to solve the EMC interference problem of secondary power supply to load equipment in satellites and spacecraft, a power supply filter must be equipped on the input side of the secondary power supply. With the rapid development of communication and navigation satellite technology, the power and current level of the secondary power supply of the spacecraft as energy gradually increase, which leads to the fact that the size of the power supply filter matched with the secondary power supply is getting larger and larger, and the size of the power supply filter is close to that of the secondary power supply body. Meanwhile, the heat consumption of the inductors and other devices in the filter is increased due to the increase of the power level, and the heat dissipation problem affects the reliability of the filter and the entire power supply system. Therefore, it is urgent to research and design a power supply filter with smaller size and higher power level.

[0003] The traditional power supply filter has two inductors and multiple sets of capacitors welded on a printed circuit board, and the space utilization rate is low. Some filters use a steel structure shell to enhance the heat dissipation capacity, so they can only be installed through a flange structure, which further occupies the area of the filter. Limited by the space radiation environment of the spacecraft, the aerospace power supply filter cannot use small-sized integrated process methods such as plastic package substrate integration process, and can only dissipate heat through conduction in a vacuum environment, so it cannot use process means such as pouring to enhance radiation heat dissipation. Through retrieval of relevant literatures at home and abroad, no high-density aerospace power supply filter based on a common-differential-mode integrated inductor and a manufacturing method are found. SUMMARY

[0004] The application solves the technical problem of overcoming the deficiencies of the prior art method, and provides a high-density aerospace power supply filter based on a common-differential-mode three-dimensional integrated inductor and a manufacturing method, which enhances the heat dissipation performance of the power supply filter under large current working conditions, improves the space utilization rate of the power supply filter, and realizes high-density assembly of the power supply filter.

[0005] The technical solution of the application is: an aerospace power supply filter based on a common-differential-mode three-dimensional integrated inductor, which comprises a common-differential-mode three-dimensional integrated inductor, a capacitor, BGA solder balls / PGA solder pins, a cover plate and a surrounding frame.

[0006] The common-differential-mode three-dimensional integrated inductor is composed of the LTCC substrate, a double-middle-column magnetic core and a matching magnetic core; the LTCC substrate is a multilayer printed ceramic substrate with an internal integrated capacitor, and four hollow regions are arranged; the double-middle-column magnetic core has two middle columns and two side columns; the double-middle-column magnetic core and the matching magnetic core are inserted into the hollow regions of the LTCC substrate and fixed, and the common-mode inductor is formed by the two middle columns of the double-middle-column magnetic core, the LTCC substrate and the matching magnetic core, and the differential-mode inductor is formed by the two side columns of the double-middle-column magnetic core, the LTCC substrate and the matching magnetic core.

[0007] The front side of the LTCC substrate leads out pads for welding differential-mode capacitors, and the back side leads out pads for welding BGA solder balls / PGA solder pins; the common-differential-mode three-dimensional integrated inductor, the surrounding frame and the cover plate form a sealed power filter structure, and the inductor top is in contact with the cover plate by filling with heat dissipation material, and the inductor extends out of the bottom of the substrate to enhance the heat dissipation capacity.

[0008] Preferably, the height of the two side columns of the double-middle-column magnetic core is designed to be lower than the height of the middle columns by h, unit: m; h=(N 2 ×μ0×A h ) / L2;

[0009] Wherein, L2 is the differential-mode inductance, unit: H; N is the number of turns of the common-mode inductor, unit: turns; A h is the effective cross-sectional area of the magnetic core, and μ0 is the air permeability.

[0010] Preferably, the four differential-mode capacitors are ceramic capacitors, which are connected in series, have a withstand voltage ≥100V and a capacity ≥6.8μF, and are welded on the LTCC substrate in a surface mounting manner.

[0011] Preferably, the main material of the LTCC substrate is AL2O3 ceramic, the common-mode capacitor is embedded inside, the winding coil of the inductor is formed by a multilayer vertical spiral structure wiring structure, the conductor current carrying capacity inside the LTCC substrate is >10A, and the power consumption of the substrate is ≤0.1W; the LTCC substrate has brazing areas around the front side for welding a metal surrounding frame, and BGA / PGA pads are led out on the back side of the ceramic substrate, and the BGA pads include four kinds of potentials in the electrical performance design, i.e., primary bus input positive, primary bus input negative, secondary power input positive, secondary power input negative and shell ground.

[0012] Preferably, the common-mode capacitor adopts a VIC structure, and the inductor winding adopts a three-dimensional spiral structure interconnection.

[0013] Preferably, the metal frame material is a Ni / Au plated Kovar alloy, which is soldered on the LTCC substrate using high-temperature solder, and the frame is at the same potential as the shell in terms of electrical characteristics; the metal cover plate material is a Ni / Au plated Kovar alloy, and the cover plate is interconnected with the frame using parallel seam welding, and the metal cover plate is at the same potential as the shell in terms of electrical characteristics, and a heat dissipation material is used to fill between the cover plate and the magnetic core, and the heat of the magnetic core is conducted away from the top during use by compacting the heat dissipation block and the metal cover plate.

[0014] Preferably, the aerospace power supply filter is suitable for high power density, and the power density of the aerospace power supply filter is greater than or equal to 5000W / in 3 .

[0015] A manufacturing method of the aerospace power supply filter based on the common differential mode three-dimensional integrated inductor, comprising:

[0016] Processing and manufacturing an LTCC substrate, the inner layer conductor of the LTCC substrate is a gold conductor, the surface layer conductor is a platinum-palladium-silver or copper conductor, the surface layer and the inner layer are interconnected by screen printing a dielectric conductor, and the printing area of the dielectric conductor should be greater than or equal to 0.3mm×0.3mm, and a common mode capacitor is embedded in the VIC structure, and an inductor winding is printed in a three-dimensional spiral structure;

[0017] Soldering the metal frame and the BGA ball / PGA solder pin, and the melting point of the high-temperature solder used in the soldering is higher than that of the low-temperature solder used in the subsequent processing steps;

[0018] Soldering the differential mode capacitor: placing the LTCC substrate on the front, applying low-temperature solder paste on the front of the LTCC substrate through a U-shaped screen plate, placing the capacitor on the corresponding pad through a chip mounter, and soldering the capacitor on the LTCC substrate through a reflow soldering furnace;

[0019] Dispensing and fixing the soldered differential mode capacitor;

[0020] Arranging the double-pillar magnetic core, the matching magnetic core, and the LTCC substrate on the same vertical line using a tool, testing the common mode inductance and the differential mode inductance at this time, pressing the double-pillar magnetic core and the matching magnetic core using a tool fixture when the differential mode inductance meets the requirements, dispensing and fixing glue at the joint of the three using a dispensing machine; keeping the double-pillar magnetic core and the matching magnetic core in a pressed state, and curing the assembly of the double-pillar magnetic core, the matching magnetic core, and the LTCC substrate in an environment required by the fixing glue;

[0021] Cleaning the LTCC substrate with the fixed magnetic core, pasting a heat-conducting insulating gasket on the inner surface of the metal cover plate, and scrubbing the metal frame on the metal cover plate and the LTCC substrate, and after baking in an inert gas environment, welding the cover plate on the LTCC frame using a parallel seam welding machine.

[0022] Preferably, the soldering of the metal frame and the BGA ball / PGA solder pin comprises:

[0023] The metal frame and the finished LTCC substrate are cleaned, and after cleaning, the LTCC substrate is inverted, high-temperature tin paste is applied to the BGA / PGA pad position at the bottom of the LTCC substrate through a screen plate, the BGA solder balls are placed on the grooved graphite tool, then the LTCC substrate is turned over to face upwards, and the BGA pad of the LTCC substrate is accurately positioned with the solder balls on the graphite tool through positioning marks, and the LTCC substrate is stacked on the graphite tool;

[0024] A square frame-shaped alloy solder is placed around the frame soldering area of the LTCC substrate, then the metal frame is stacked, and finally, a copper pressing block is placed on the metal frame, so that the LTCC substrate, the BGA solder balls and the metal frame are fixed firmly by the high-temperature-resistant graphite tool and the copper pressing block, preventing the position deviation of the solder balls or the frame during high-temperature soldering;

[0025] A vacuum soldering furnace is used for sintering.

[0026] Preferably, the finished differential mode capacitor is glued and fixed, the position of the fixing glue should be on both sides of the body of the capacitor other than the pad, the fixing glue is selected to have good fixing properties at high temperature and not to be prone to cracking due to temperature change, and the fixing height should be less than or equal to the height of the differential mode capacitor.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] (1) The common-differential mode three-dimensional integrated inductor in the present application utilizes the characteristic of the LTCC substrate that multiple layers of spiral conductive wires can be printed to manufacture the inductor coil, so that the inductor coil is three-dimensional, and the space utilization is improved. Secondly, the common-differential mode three-dimensional integrated inductor integrates the common mode inductor and the differential mode inductor by controlling the height difference between the middle column and the side column of the double middle column magnetic core, so that one set of magnetic core can realize the function of two inductors, and the planar size of the filter is saved. Finally, the top of the magnetic core of the common-differential mode three-dimensional integrated inductor is in contact with the cover plate for heat dissipation, and the bottom of the magnetic core is exposed to the bottom surface of the filter, which increases the heat dissipation contact ability of the inductor as the core heat source, and the double middle column magnetic core and the high-temperature solder ball can greatly buffer the problem of mismatching of the thermal expansion coefficients of the LTCC ceramic substrate of the filter and the PCB substrate of the user in the present application.

[0029] (2) The high-density spaceflight power filter based on the common-differential mode three-dimensional integrated inductor realizes the integration of all four kinds of elements, i.e., the common mode inductor, the differential mode inductor, the common mode capacitor and the differential mode capacitor, the common mode capacitor with small heat generation and small capacitance is built-in the LTCC substrate, the differential mode capacitor with large heat generation and large capacitance is surface-mounted on the LTCC substrate, and the inductor is in contact with the top and bottom for heat dissipation, which can better adapt to the spaceflight power working condition of large current;

[0030] (3) The manufacturing method of the high-density aerospace power supply filter based on the common-differential-mode three-dimensional integrated inductor of the application can effectively prevent the secondary melting of the BGA solder ball, capacitor and other soldered devices during the manufacturing or use of the filter. In addition, the inductance of the common-differential-mode three-dimensional integrated inductor can be artificially controlled during the manufacturing process, so that the adjustment of the filter parameters can be realized to meet the needs of different power supply products. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of the power supply filter circuit of the application.

[0032] Figure 2 The figure is a structural diagram of the high-density aerospace power supply filter based on the common-differential-mode three-dimensional integrated inductor of the application.

[0033] Figure 3 The figure is a schematic diagram of the assembly of the inductor and the substrate in the filter.

[0034] Figure 4 The figure is the assembly structure of the common-differential-mode three-dimensional integrated inductor.

[0035] Figure 5 The figure is a flow chart of the manufacturing method of the high-density aerospace power supply filter based on the common-differential-mode three-dimensional integrated inductor of the application.

[0036] Figure 6 The figure is a schematic diagram of step 2 in the manufacturing method of the high-density aerospace power supply filter based on the common-differential-mode three-dimensional integrated inductor of the application. DETAILED DESCRIPTION

[0037] The application will be further described below in combination with the embodiments.

[0038] The embodiment of the high-density aerospace power supply filter based on the common-differential-mode three-dimensional integrated inductor is described.

[0039] The aerospace power supply filter of the application can realize the power density index greater than or equal to 5000W / in 3 In the embodiment, the rated power of the aerospace power supply filter is 300W, the size is less than or equal to 16mmx16mmx3.5mm, and the power density is greater than or equal to 5357W / in 3 .

[0040] Figure 1 and Figure 2The diagrams shown are a schematic diagram and a structural diagram of the high-density aerospace power filter circuit based on a common-mode three-dimensional integrated inductor of the present invention. The high-density aerospace power filter based on a common-mode three-dimensional integrated inductor includes a dual-core magnetic core 1, an LTCC substrate 2 integrating common-mode capacitors C3, C4, C5, C6 and inductor windings, four differential-mode capacitors 3 (C1, C2, C7, C8), 24 BGA solder balls 4, a matching magnetic core 5, a metal cover plate 6, and a metal frame 7.

[0041] The dual-core magnetic material is a ferrite material with high permeability. In this embodiment, the dual-core magnetic material is 3E6. The dual-core magnetic material has two cores and two side cores. The height of the two side cores is designed to be h (in meters) lower than the height of the cores. The magnitude of this height difference is determined by the value of the differential-mode inductance L2 (in meters) required for the filter. It should be calculated after the common-mode inductor design is completed, based on the number of turns N (in turns) of the common-mode inductor and the effective cross-sectional area Ah of the dual-core magnetic material. The calculation formula is: h = (N² × μ₀ × Ah) / (N² × μ₀ ... h ) / L2. The dimensions of the dual-core magnetic core used in this embodiment are 14mm×5mm×2mm. The height of the two side pillars is designed to be 0.1mm lower than the height of the core. The dimensions of the two side pillars are 5mm×1mm×1.9mm, and the dimensions of the two cores are 5mm×1mm×2mm. The inductance of the common-mode inductor is designed to be 560μH, and the inductance of the differential-mode inductor is designed to be 10μH.

[0042] The LTCC substrate is primarily made of Al₂O₃ ceramic, internally integrating common-mode capacitors, inductor windings, and conductors. Conductor printing is employed. Based on aerospace ceramic capacitor selection requirements, the common-mode capacitor has a capacitance of 100pF and a withstand voltage ≥100V. In this embodiment, the embedded common-mode capacitor uses a VIC structure, with silver electrodes and a ceramic dielectric material of 7.8 dielectric constant, 0.0047 dielectric loss, and a thickness of 35μm. The internal inductor windings of the LTCC substrate utilize… Figure 3 The interconnected three-dimensional spiral structure shown has a coil turn count calculated based on the inductance coefficient AL value of the magnetic core material used. In this embodiment, the inductor winding coil inside the LTCC substrate has 10 turns.

[0043] The inner metal layer of the LTCC substrate uses gold conductors, while the outer layer uses platinum-palladium-silver conductors to increase current carrying capacity. The conductor width is adjusted according to the current magnitude, and the conductor current density should be less than or equal to 10 A / mm². 2 The vias connecting the inner and outer conductors are filled with silver paste, and the via dimensions are designed to be 0.3mm × 0.3mm. 24 BGA / PGA pads are led out from the back of the LTCC substrate. The number of pads is calculated based on the current, and the current density should be less than or equal to 10A / mm². 2The electrical performance design of BGA pads includes four potentials: primary bus input positive, primary bus input negative, secondary power input positive, secondary power input negative, and case ground. The pads are circular in shape. To ensure soldering quality, the design standard for pad size is as follows: when using 0.89mm diameter solder balls, the pad size should be designed to be 0.86mm with a pitch of 1.27mm; when using 0.76mm diameter solder balls, the pad size should be designed to be 0.76mm with a pitch of 1mm.

[0044] The four differential-mode capacitors are ceramic capacitors. Considering the derating standards and reliability design criteria of aerospace power supplies, the capacitors should be connected in series, with a withstand voltage of ≥100V and a capacitance of ≥6.8μF to ensure that the filter has good differential-mode interference suppression. The ceramic capacitors are soldered onto the LTCC substrate using reflow soldering.

[0045] BGA solder balls are high-temperature solder balls made of Pb90Sn10 material, with a diameter of 0.89mm and a pitch of 1.27mm. BGA solder balls serve as electrical and mechanical connections.

[0046] The matching magnetic core is made of the same material as the dual-column magnetic core, and has the same length and width as the dual-column magnetic core. Its height is consistent with the height of the BGA solder balls. In this embodiment, the dual-column magnetic core is made of 3E6 material, and the matching magnetic core has a size of 14mm×5mm×1mm.

[0047] The metal frame is made of 4J29 Kovar alloy with Ni / Au plating. The frame is designed to be at the same electrical potential as the filter's shell and ground, and the frame thickness is 0.6mm.

[0048] The metal cover plate is made of 4J29 Kovar alloy with Ni / Au plating. The cover plate is designed to be at the same potential as the filter shell ground in terms of electrical performance. The cover plate is a stepped cover plate with a thickness of 0.25mm. The cover plate thickness at the sealing part where the cover plate contacts the frame is 0.1mm. The fillet radius of the cover plate and the welding ring is 0.8mm.

[0049] like Figure 4 As shown, the common-mode and differential-mode integrated inductor consists of a dual-core magnetic core, a matching core, and an LTCC substrate bonded together. The LTCC substrate has four hollow areas in the middle for the dual-core magnetic core to pass through. After passing through the LTCC substrate, the dual-core magnetic core is bonded to the matching core, forming a common-mode inductor L1 and a differential-mode inductor L2. The dual cores of the dual-core magnetic core, the LTCC substrate, and the matching core form the common-mode inductor L1, with an inductance of 560μH. The side cores of the dual-core magnetic core, the LTCC substrate, and the matching core form the differential-mode inductor, with an inductance of 10μH. The top of the magnetic core contacts the cover plate for heat dissipation, while the bottom of the magnetic core is exposed on the bottom surface of the filter to increase the heat dissipation contact area. Simultaneously, the bottom surface of the magnetic core is coplanar with the BGA solder balls, serving as a mechanical mounting interface together with the BGA solder balls.

[0050] An example of a manufacturing method for a high-density aerospace power filter based on a common-mode stereointegrated inductor is described.

[0051] like Figure 5 As shown, the manufacturing method of a high-density aerospace power filter based on a common-mode three-dimensional integrated inductor is illustrated in the following embodiment.

[0052] Step 1:

[0053] Fabrication of LTCC multilayer ceramic substrates. Based on the preliminary electrical design, mechanical design, and layout design, the LTCC multilayer substrates are fabricated. Among them, the common mode inductor winding should adopt a three-dimensional spiral structure printing.

[0054] Step 2:

[0055] Solder the metal frame and BGA balls. For example... Figure 6 As shown, the high-temperature welding fixture assembly for the metal frame and BGA solder balls includes a copper clamping block 8 and a graphite fixture 9.

[0056] Step 2-1. Clean the metal frame of the integrated common-mode capacitor and inductor winding coil, and the LTCC substrate in trichloroethane solution. After cleaning, invert the LTCC substrate and apply high-temperature solder paste to the BGA / PGA pads on the bottom of the LTCC substrate using a stencil. The melting point of the high-temperature solder paste used for soldering should be higher than that of the low-temperature solder paste used in subsequent processing steps. In this example, step 2-1 uses 5087 high-temperature solder paste with a thickness of 80-100 μm. Place the Pb90Sn10 BGA solder balls on a pre-grooved graphite fixture, then flip the LTCC substrate face up. After precisely aligning the BGA pads of the LTCC substrate with the solder balls on the graphite fixture using positioning marks, stack the LTCC substrate on top of the graphite fixture.

[0057] Step 2-2. Place a square-shaped alloy solder around the LTCC substrate in the surrounding frame soldering area, then stack a metal frame on top, and finally place a copper pressure block on top of the metal frame. This ensures that the LTCC substrate, BGA solder balls, and metal frame are firmly fixed by the high-temperature resistant graphite fixture and the copper pressure block, preventing the solder balls or frame from shifting during high-temperature soldering.

[0058] Steps 2-3. The high-temperature welding fixture assembly of the metal frame and BGA solder balls is sintered in a vacuum welding furnace for 30 minutes, with a peak sintering temperature of 360-400℃.

[0059] Step 3:

[0060] Solder the differential mode capacitor. Place the LTCC substrate face up, apply Pb63Sn37 solder paste on the LTCC substrate face through the U-shaped mesh, the thickness of the solder paste is 80-100 μm, place the capacitor on the corresponding pad through the chip mounter, and solder the capacitor on the LTCC substrate through the reflow soldering furnace.

[0061] Step 4:

[0062] Manufacture the three-dimensional integrated inductance and device fixation of the common differential mode.

[0063] Step 4-1. Manually glue the soldered differential mode capacitor, the position of the fixing glue should be on both sides of the body of the capacitor other than the pad, and the height of the fixing glue should be less than or equal to the height of the differential mode capacitor. The fixing glue should be selected as much as possible to have good fixing properties at high temperatures, and the fixing glue should not be easily cracked due to temperature changes. The type of the fixing glue in the embodiment is EMS400-36.

[0064] Step 4-2.

[0065] Arrange the double-pillar magnetic core, the matching magnetic core and the LTCC substrate on the same vertical line through the device, test the common mode inductance and the differential mode inductance at this time, compact the double-pillar magnetic core and the matching magnetic core when the differential mode inductance meets the requirements, and point the fixing glue at the joint of the three through the glue dispenser. The fixing glue should be selected as much as possible to have good fixing properties at high temperatures, and the fixing glue should not be easily cracked due to temperature changes. The type of the fixing glue in the embodiment is EMS400-36. Keep the double-pillar magnetic core and the matching magnetic core in the compact state, and store the assembly of the double-pillar magnetic core, the matching magnetic core and the LTCC substrate in a 120℃ environment, and stand still for 45 minutes for solidification.

[0066] Step 5:

[0067] Cover plate welding. Clean the LTCC substrate with the fixed magnetic core, paste the heat-conducting insulating gasket on the inner surface of the metal cover plate, and scrub the metal cover plate and the metal frame on the LTCC substrate, and after baking in an inert gas environment, weld the cover plate on the LTCC frame through the parallel seam welding machine.

[0068] The three-dimensional integrated common differential mode inductance of the application greatly improves the space utilization, reduces the size of the power filter by more than 50%, at the same time, the double-sided interconnection of the LTCC substrate reduces the line loss, the inductance top contacts with the cover plate for heat dissipation, and the bottom extends out of the substrate to enhance the heat dissipation capacity, so that the power filter of the application can adapt to larger current and high power application occasions.

[0069] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application shall fall within the protection scope of the technical solutions of the present application.

Claims

1. A space power filter based on common-differential-mode three-dimensional integrated inductors, characterized by It comprises a common-differential-mode three-dimensional integrated inductor, a capacitor, a BGA solder ball / PGA solder pin, a metal cover plate and a metal frame; The common-differential-mode three-dimensional integrated inductor is composed of an LTCC substrate, a double-column magnetic core and a matching magnetic core; the LTCC substrate is a multilayer printed ceramic substrate with an internal integrated common-mode capacitor, and four hollow areas are arranged; the double-column magnetic core has two columns and two side columns; the double-column magnetic core is inserted into the hollow area of the LTCC substrate, and the matching magnetic core is fixed at the lower part of the LTCC substrate; the common-mode inductor is formed by the two columns of the double-column magnetic core, the LTCC substrate and the matching magnetic core, and the differential-mode inductor is formed by the two side columns of the double-column magnetic core, the LTCC substrate and the matching magnetic core. The front pad of the LTCC substrate is used for welding a differential-mode capacitor, and the back pad is used for welding a BGA solder ball / PGA solder pin; the common-differential-mode three-dimensional integrated inductor, the metal frame and the metal cover plate form a sealed power filter structure, the top of the inductor is in contact with the metal cover plate through a heat dissipation material, and the inductor extends out of the bottom of the LTCC substrate to enhance the heat dissipation capacity. The two side columns of the double-column magnetic core are designed to be lower than the middle column by a height h, unit: m; h=(N 2 × μ0× A h ) / L2; Wherein, L2 is the differential mode inductance, unit: H; N is the common mode inductance number of turns, unit: turns; A h Aeff is the effective cross-sectional area of the magnetic core, and μ0 is the air permeability.

2. The power filter of claim 1, wherein: The four differential-mode capacitors are ceramic capacitors, which are connected in series, have a voltage resistance value of ≥100V and a capacity of ≥6.8μF, and are welded on the LTCC substrate in a surface mounting manner.

3. The power filter of claim 1, wherein: The main material of the LTCC substrate is AL2O3 ceramic, the common-mode capacitor is embedded inside, the inductor winding is formed through a multilayer vertical spiral structure wiring structure, the conductor current carrying capacity inside the LTCC substrate is >10A, and the substrate power consumption is ≤0.1W; a brazing area is left around the front of the LTCC substrate for welding the metal frame, a BGA / PGA pad is led out at the back of the ceramic substrate, the BGA pad contains four kinds of potentials in the electrical performance design, i.e., a primary bus input positive, a primary bus input negative, a secondary power input positive and a secondary power input negative, wherein the primary bus input negative and the secondary power input negative are both grounded as the same potential.

4. The power filter of claim 3, wherein: The common-mode capacitor adopts a VIC structure, and the inductor winding adopts a three-dimensional spiral structure interconnection.

5. The power filter of claim 1, wherein: The material of the metal frame is Kovar alloy with a surface plated with Ni / Au, which is brazed on the LTCC substrate by high-temperature solder, and the metal frame has the same potential as the shell ground in electrical characteristics; the material of the metal cover plate is Kovar alloy with a surface plated with Ni / Au, and the metal cover plate is interconnected with the metal frame by parallel seam welding process, and the metal cover plate has the same potential as the shell ground in electrical characteristics; heat dissipation material is used to fill between the metal cover plate and the magnetic core, and the heat of the magnetic core is conducted out from the top by compacting the heat dissipation block and the metal cover plate during use.

6. A power filter according to one of claims 1-5, characterized in that: Power supply filter suitable for high power density, the power density of the power supply filter is greater than or equal to 5000W / in 3 .

7. A method of fabricating a space power filter based on the common-differential mode three-dimensional integrated inductor of claim 1, characterized by It comprises: processing and manufacturing an LTCC substrate, the inner conductor of the LTCC substrate is a gold conductor, the surface conductor is a platinum-palladium-silver or copper conductor, the surface layer and the inner layer are interconnected through a silk-screen printed medium conductor, the silk-screen printed medium conductor has a printing area of ≥0.3mm×0.3mm, a VIC structure is used to embed a common-mode capacitor, and a three-dimensional spiral structure is used to print an inductor winding; welding a metal frame and a BGA ball / PGA solder pin, and the melting point of the high-temperature solder used in the welding is higher than that of the low-temperature solder used in the subsequent processing steps; Soldering differential mode capacitor: placing the LTCC substrate on the front, applying low-temperature tin paste on the front of the LTCC substrate through the U-shaped mesh plate, placing the differential mode capacitor on the corresponding pad through the chip mount machine, and soldering the differential mode capacitor on the LTCC substrate through the reflow soldering furnace; Dispensing and fixing the differential mode capacitor after soldering is completed; Place the double middle column magnetic core, the matching magnetic core, and the LTCC substrate on the same vertical line through the tool, test the common mode inductance and the differential mode inductance at this time, and when the differential mode inductance meets the requirements, use the tool clamp to compact the double middle column magnetic core and the matching magnetic core, and fix the glue at the joint of the three through the dispensing machine; keep the double middle column magnetic core and the matching magnetic core in the compacted state, and solidify the assembly of the double middle column magnetic core, the matching magnetic core, and the LTCC substrate in the environment required by the fixing glue. Clean the LTCC substrate with the fixed magnetic core, paste the heat-conducting insulating gasket on the inner surface of the metal cover plate, scrub the metal cover plate and the metal frame on the LTCC substrate, and then bake in an inert gas environment. Through the parallel seam welding machine, the metal cover plate is welded on the LTCC metal frame.

8. The manufacturing method according to claim 7, characterized in that: The soldered metal frame and BGA ball / PGA soldering needle include: Clean the metal frame and the LTCC substrate after processing and manufacturing are completed; after cleaning, invert the LTCC substrate, and apply high-temperature tin paste on the BGA / PGA pad position at the bottom of the LTCC substrate through the mesh plate; place the BGA soldering ball on the graphite tool with a groove, then turn the LTCC substrate upside down, and accurately align the BGA pad of the LTCC substrate with the soldering ball on the graphite tool through the positioning mark, and then stack the LTCC substrate on the graphite tool; Place a square alloy soldering material around the metal frame welding area of the LTCC substrate, then stack the metal frame, and finally place a copper pressing block on the metal frame, so that the LTCC substrate, BGA soldering ball, and metal frame are firmly fixed by the high-temperature-resistant graphite tool and copper pressing block, preventing the soldering ball or metal frame from shifting position during high-temperature soldering; Use a vacuum soldering furnace for sintering.

9. The manufacturing method of claim 7, wherein: Dispensing and fixing the differential mode capacitor after soldering is completed, the position of the fixing glue should be on both sides of the body of the differential mode capacitor, the fixing glue should have good fixing properties at high temperature and should not easily crack due to temperature changes, and the fixing height should be less than or equal to the height of the differential mode capacitor.

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