Boost inductor for reducing inverter losses

Abstract

The application provides a boost inductor for reducing loss of an inverter, and relates to the technical field of inverters.The magnetic core adopts a hierarchical nanocrystalline soft magnetic composite material, the magnetic core is composed of iron-based nanocrystalline alloy particles, the particle size gradually changes from 10-15 microns in the center layer to 25-50 microns in the outer layer, a gradient structure is formed through a layered compaction process, the winding includes a main winding and an auxiliary winding, the main winding is a high-conductivity oxygen-free copper wire, the auxiliary winding is a carbon nanotube reinforced copper composite wire containing 1% of multi-walled carbon nanotubes by weight, the main winding is wound in a standard spiral manner, the auxiliary winding is inserted between the turns of the main winding in an interleaved manner, the layered compaction forms a gradient structure, the magnetic field distribution is significantly optimized and the eddy current loss is reduced, the stability of the gradient structure is ensured, the magnetic core has both the high saturation magnetic induction intensity of the nanocrystalline alloy and the low loss characteristic of the hierarchical nanocrystalline soft magnetic composite material, and therefore the effect of improving the high-frequency working efficiency of the inverter is achieved.

Description

Technical Field

[0001] This invention relates to the field of inverter technology, specifically to a boost inductor for reducing inverter losses. Background Technology

[0002] According to Chinese Patent Publication No. CN101477868B, a soft magnetic core for a high-power inverter and its manufacturing method are disclosed. The core is made of iron-based amorphous nanocrystalline ribbon wound together. The core composition by mass fraction is: Fe: 81%–85%, Co: 0.01%–5%, Si: 7%–9%, ​​B: 1.5%–2.5%, Cu: 1%–2%, M: 4%–7%, M': 0.001%–0.04%, where M represents Nb, Mo, and V. One or more of W and Ta, and M' is at least one of Al and Ti. The magnetic core is annealed in a protective atmosphere or vacuum. During annealing, the position of the magnetic core in the furnace can be moved or rotated. The holding temperature is 520-600℃, the holding time is 1-2 hours, and the heating rate is 100℃ / hour. The magnetic core manufactured by the above method has lower loss and better manufacturing process performance. It not only has excellent soft magnetic properties, but also can be processed by a variety of processes after heat treatment.

[0003] The aforementioned patent documents and prior art have the following technical problems when used:

[0004] Problem 1: The magnetic core materials (such as ferrite or ordinary iron-based alloys) used in the boost inductors of traditional inverters often have poor performance under high-frequency operating conditions. The eddy current loss and hysteresis loss of the magnetic core are large, resulting in serious energy dissipation, especially in high-frequency applications such as photovoltaic inverters, where the efficiency drops significantly.

[0005] Question 2: The winding material of existing inverter inductors mostly uses a single copper wire (such as ordinary oxygen-free copper wire). Although the DC resistance is low, under high frequency conditions, due to the influence of the skin effect and proximity effect, the AC resistance increases significantly, resulting in a significant increase in copper loss. The single material design cannot effectively cope with the simultaneous DC and AC components in the inverter. Especially in the scenario with large high frequency ripple, the loss problem is particularly prominent, which limits the overall performance of the inductor.

[0006] Problem 3: The existing winding process of inverter inductors (such as simple spiral winding or random winding) often leads to uneven magnetic field distribution and obvious leakage flux. Especially under high frequency and high power conditions, parasitic capacitance and leakage flux loss increase significantly. These problems not only increase the overall loss of the inductor, but also affect the stability of the inverter, leading to increased electromagnetic interference or decreased inductor performance. Summary of the Invention

[0007] Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a boost inductor for reducing inverter losses, solving the following problems:

[0009] 1. Addressing the issues of high core material loss and low high-frequency efficiency;

[0010] 2. Addressing the issues of high winding copper loss and significant high-frequency AC losses;

[0011] 3. To address the problem of uneven magnetic field distribution, leakage flux, and severe parasitic effects caused by single winding.

[0012] Technical solution

[0013] To achieve the above objectives, the present invention provides the following technical solution: a boost inductor for reducing inverter losses, comprising a core and windings. The core is a graded nanocrystalline soft magnetic composite material core, which is composed of iron-based nanocrystalline alloy particles with particle sizes gradually varying from 10-15 micrometers in the central layer to 25-50 micrometers in the outer layer, forming a gradient structure through a layered compaction process. The iron-based nanocrystalline alloy comprises iron and cobalt with a total mass percentage of not less than 73%, and has an insulating coating on its exterior. The windings include a main winding and an auxiliary winding. The main winding is a highly conductive oxygen-free copper wire used to handle direct current, and the auxiliary winding is a carbon nanotube-reinforced copper composite wire containing 1% by weight of multi-walled carbon nanotubes used to handle AC ripple. The main winding is wound in a standard spiral pattern, and the auxiliary winding is inserted between the main winding turns in an interleaved manner, with the main winding and auxiliary winding connected in parallel.

[0014] Preferably, the composition of the iron-based nanocrystalline alloy by mass fraction is: cobalt: 5-10%, niobium: 2-2.5%; copper: 0.8-1%; silicon: 11-12%, boron: 8-9%; manganese: 1-1.5%; the cobalt content is adjusted to make Fe + Co ≥ 73%.

[0015] Preferably, the graded nanocrystalline soft magnetic composite core has a three-layer gradient structure, with a central layer, an intermediate layer and an outer layer respectively. The particle size of the central layer is 10-15 micrometers, the particle size of the intermediate layer is 15-25 micrometers, and the particle size of the outer layer is 25-50 micrometers. The insulating coating is epoxy resin or ceramic material, and the coating thickness is 0.1-0.5 micrometers.

[0016] Preferably, the forming method of the magnetic core includes the following steps:

[0017] Sp1: Alloy Production: Iron-based nanocrystalline alloys were prepared using rapid solidification technology with a cooling rate of 10°C. 5 -10 6 K / s;

[0018] Sp2: Particle preparation: The alloy is ground into three types of particles: 10-15 micrometers, 15-25 micrometers, and 25-50 micrometers, with the particle size distribution controlled within ±5%;

[0019] Sp3: Insulating coating: Epoxy resin or ceramic is coated using a spraying or dipping process, with uniform coating thickness to prevent interparticle eddy currents;

[0020] Sp4: Layered compaction: Use a mold for layered compaction, first compact the central layer, then compact the middle and outer layers, with a compaction pressure of 100-200MPa;

[0021] Sp5: Heat treatment: Anneal at 400-600℃ for 1-2 hours;

[0022] Sp6: Final processing: Machining to the target shape while maintaining the integrity of the gradient structure.

[0023] Preferably, the oxygen-free copper wire of the main winding is of type C10100-TU0, with a conductivity between 99% and 101% IACS, a wire diameter of 0.5-1.5 mm, an insulation layer of polyimide or polyester with a thickness of 0.05-0.1 mm, and a withstand voltage range of 220V-10kV.

[0024] Preferably, the carbon nanotube-reinforced copper composite wire of the auxiliary winding is composed of high-purity oxygen-free copper and 1% by weight of multi-walled carbon nanotubes, with a wire diameter of 0.2-0.5 mm and an insulation layer thickness of 0.03-0.08 mm.

[0025] Preferably, the winding process of the winding includes the following steps:

[0026] Sp1: Calculate the number of turns N of the main winding and the number of turns M of the auxiliary winding, where N is determined based on the inductance and DC current, and M is 0.3-0.5 times N;

[0027] Sp2: The main winding is wound N turns in a standard spiral manner, and the tension fluctuation is controlled within ±1N;

[0028] Sp3: The auxiliary winding is wound in an alternating manner with M turns, each turn being offset from the main winding by 15°-30°, and the tension fluctuation is controlled within ±0.5N;

[0029] Sp4: The two are connected in parallel, and the contact resistance is less than 0.01Ω.

[0030] Preferably, the winding process of the winding uses a high-precision winding machine, the winding speed of the main winding is 5-10 rpm, the winding speed of the auxiliary winding is 10-15 rpm, and the misalignment angle of the auxiliary winding is controlled by a precision positioning device, with the angle deviation not exceeding ±1°.

[0031] Preferably, the boost inductor undergoes quality inspection after winding, specifically including the following inspection items:

[0032] Inductance is measured every 50 turns, with the deviation controlled within ±2%.

[0033] X-ray inspection is used to check for internal defects in the windings;

[0034] Overall performance testing includes withstand voltage testing (220V-10KV), DC resistance testing, and AC loss testing.

[0035] Beneficial effects

[0036] This invention provides a boost inductor for reducing inverter losses. It offers the following advantages:

[0037] 1. This invention employs a graded nanocrystalline soft magnetic composite core, with particle size gradually varying from 10-15 micrometers at the center to 25-50 micrometers at the outer layer. This gradient structure, achieved through layered compaction, significantly optimizes the magnetic field distribution and reduces eddy current losses. The high permeability of the fine particles (10-15 micrometers) in the center layer effectively constrains the magnetic flux in strong magnetic field regions, improving the core's magnetic performance under high-frequency conditions. Simultaneously, the larger particles (25-50 micrometers) in the outer layer reduce eddy current losses in weaker magnetic field regions, minimizing energy dissipation caused by high-frequency alternating magnetic fields. The layered compaction process ensures the stability of the gradient structure, giving the core both the high saturation magnetic induction of nanocrystalline alloys and the low-loss characteristics of graded nanocrystalline soft magnetic composite materials. This enhances the high-frequency operating efficiency of inverters, making it suitable for high-frequency applications such as photovoltaic inverters. It significantly reduces core losses and improves overall energy conversion efficiency.

[0038] 2. This invention employs a dual-wire winding technology. The main winding uses highly conductive oxygen-free copper wire to handle DC current, while the auxiliary winding uses carbon nanotube-reinforced copper composite wire containing 1% multi-walled carbon nanotubes to handle AC ripple. This achieves the function of optimizing the transmission of DC and AC components of current respectively. The main winding uses C10100-TU0 oxygen-free copper wire, with a conductivity between 99% and 101% IACS and a relatively thick wire diameter (0.5-1.5mm). It has extremely low DC resistance and can efficiently transmit the large DC current component in the inverter, reducing copper losses. The auxiliary winding uses carbon nanotube-reinforced copper composite wire. The low skin effect of carbon nanotubes significantly reduces AC resistance under high-frequency AC ripple, and the relatively thin wire diameter (0.2-0.5mm) further optimizes high-frequency performance. Through this dual-wire combination design, the effects of reducing copper losses and reducing high-frequency AC losses are achieved. This winding configuration can maintain low-loss characteristics under high-frequency and high-power conditions, improving the operating stability of the inverter.

[0039] 3. This invention employs an interleaved parallel winding process. The main winding is wound in a standard spiral pattern, while the auxiliary winding is inserted between the main winding turns at a 15°-30° offset and connected in parallel. This optimizes current distribution and reduces leakage flux, thereby improving the overall performance of the inductor. The spiral winding of the main winding ensures uniform DC current distribution and reduces local resistance losses. The interleaved winding of the auxiliary winding is controlled by a precision positioning device, with each turn offset from the main winding by 15°-30°, effectively reducing magnetic field interference and leakage flux. It also optimizes the distribution of AC ripple. After the two are connected in parallel, the current is rationally distributed between the main winding and the auxiliary winding according to the frequency characteristics. The DC component mainly flows through the low-resistance copper wire, while the AC component is mostly carried by the carbon nanotube composite wire. This achieves the effect of reducing overall losses and improving inductor stability. It not only reduces parasitic capacitance and copper losses but also enhances the reliability of the inductor under complex operating conditions, making it particularly suitable for the high-efficiency operation requirements of high-frequency inverters. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the boost inductor core and winding structure of the present invention;

[0041] Figure 2 This is a particle size distribution diagram of the graded nanocrystalline soft magnetic composite material core of the present invention;

[0042] Figure 3 This is a comparison chart of efficiency and temperature in a specific embodiment five of the present invention;

[0043] Figure 4 This is a comparison diagram of copper losses between the single-winding inductor and the double-winding inductor of the present invention;

[0044] Figure 5 This is an efficiency comparison chart in the application case of a specific embodiment five of the present invention;

[0045] Figure 6 This is a comparison diagram of the inductor loss components of the present invention;

[0046] Figure 7 This is a schematic diagram of the temperature distribution of the magnetic core in this invention;

[0047] Figure 8 This is a graph showing the variation of the core loss of the present invention with frequency and magnetic flux density;

[0048] Figure 9 This is a graph showing the loss ratio of the solar inverter in a specific embodiment five of the present invention. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0051] like Figures 1 to 9 As shown, a boost inductor for reducing inverter losses includes a core and windings. The core is a graded nanocrystalline soft magnetic composite material core, which is composed of iron-based nanocrystalline alloy particles with particle sizes gradually changing from 10-15 micrometers in the central layer to 25-50 micrometers in the outer layer. A gradient structure is formed through a layered compaction process. The iron-based nanocrystalline alloy contains iron and cobalt by mass percentage of not less than 73%, and the iron-based nanocrystalline alloy is coated with an insulating layer. The windings include a main winding and an auxiliary winding. The main winding is a highly conductive oxygen-free copper wire used to handle DC current. The auxiliary winding is a carbon nanotube-reinforced copper composite wire containing 1% by weight of multi-walled carbon nanotubes used to handle AC ripple. The main winding is wound in a standard spiral pattern, and the auxiliary winding is inserted between the main winding turns in an interleaved manner. The two are connected in parallel to optimize the current distribution of DC and AC components, thereby reducing copper loss and core loss.

[0052] The composition of the iron-based nanocrystalline alloy, by mass fraction, is: cobalt: 5-10%, niobium: 2-2.5%; copper: 0.8-1%; silicon: 11-12%, boron: 8-9%; manganese: 1-1.5%. The cobalt content is adjusted to ensure Fe+Co ≥ 73%. The graded nanocrystalline soft magnetic composite core has a three-layer gradient structure, located in the central, middle, and outer layers. The particle size is 10-15 micrometers in the central layer, 15-25 micrometers in the middle layer, and 25-50 micrometers in the outer layer. The insulating coating is epoxy resin or ceramic material with a thickness of 0.1-0.5 micrometers. The graded nanocrystalline soft magnetic composite core uses a particle size that gradually changes from 10-15 micrometers in the center to 25-50 micrometers in the outer layer. The layered compaction process creates a gradient structure that significantly optimizes the magnetic field distribution and reduces eddy current losses. Utilizing the high permeability of the fine particles (10-15 micrometers) in the central layer, the magnetic flux in strong magnetic field regions is effectively confined, improving the magnetic performance of the core under high-frequency conditions. Simultaneously, the larger particles (25-50 micrometers) in the outer layer reduce eddy current losses in weaker magnetic field regions, minimizing energy dissipation caused by high-frequency alternating magnetic fields. This layered compaction process ensures the stability of the gradient structure, giving the core both the high saturation magnetic induction of nanocrystalline alloys and the low-loss characteristics of graded nanocrystalline soft magnetic composite materials. This results in improved high-frequency inverter efficiency, making it suitable for high-frequency applications such as photovoltaic inverters. It significantly reduces core losses and improves overall energy conversion efficiency.

[0053] The main winding uses oxygen-free copper wire of type C10100-TU0, with a conductivity between 99% and 101% IACS, a wire diameter of 0.5-1.5 mm, and an insulation layer of polyimide or polyester with a thickness of 0.05-0.1 mm. The withstand voltage range is 220V-10kV. The auxiliary winding uses carbon nanotube-reinforced copper composite wire composed of high-purity oxygen-free copper (purity ≥99.99%) and 1% by weight of multi-walled carbon nanotubes. The wire diameter is 0.2-0.5 mm, and the insulation layer thickness is 0.03-0.08 mm. A dual-wire winding technology is used: the main winding uses highly conductive oxygen-free copper wire to handle DC current, while the auxiliary winding uses carbon nanotube-reinforced copper composite wire containing 1% multi-walled carbon nanotubes to handle AC ripple, achieving optimization of DC and AC current respectively. For the function of AC component current transmission, the main winding uses C10100-TU0 oxygen-free copper wire with a conductivity between 99% and 101% IACS and a relatively thick wire diameter (0.5-1.5mm). It has extremely low DC resistance and can efficiently transmit the large DC current component in the inverter, reducing copper losses. The auxiliary winding uses carbon nanotube-reinforced copper composite wire. The low skin effect of carbon nanotubes significantly reduces the AC resistance under high-frequency AC ripple, and the thinner wire diameter (0.2-0.5mm) further optimizes high-frequency performance. Through this dual-wire combination design, the copper loss and high-frequency AC loss are reduced. This winding configuration can maintain low loss characteristics under high-frequency and high-power conditions and improve the operating stability of the inverter. Specific Implementation Example 2:

[0055] like Figures 1 to 9 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0056] The forming steps of the magnetic core, the forming steps of the winding, and the forming process of the entire boost inductor are as follows:

[0057] The molding steps for magnetic core materials are as follows: hierarchical nanocrystalline soft magnetic composite material magnetic core;

[0058] Sp1: Alloy Production

[0059] Sp1.1: Raw material preparation: Select high-purity raw materials, including iron (Fe, purity ≥99.9%), cobalt (Co, purity ≥99.95%), niobium (Nb, purity ≥99.9%), copper (Cu, purity ≥99.99%), silicon (Si, purity ≥99.99%), boron (B, purity ≥99.5%), and manganese (Mn, purity ≥99.9%), and weigh them according to the mass percentage (Fe + Co ≥73%, Co 5-10%, Nb 2-2.5%, Cu 0.8-1%, Si 12-13%, B 8-9%, Mn 1-1.5%).

[0060] Sp1.2: Melting: Place the raw materials in a vacuum induction melting furnace, control the melting temperature at 1450-1500℃, and maintain the vacuum level inside the furnace at 10. -3 Below Pa, stir evenly to ensure consistency of ingredients;

[0061] Sp1.3: Rapid solidification: Utilizing melt spinning technology, molten alloy is sprayed through a nozzle onto a high-speed rotating copper roller (20-30 m / s), with the cooling rate controlled at 10... 5 -10 6 K / s, forming an amorphous ribbon with a thickness of 20-30 micrometers to ensure the uniformity of the nanocrystalline precursor structure;

[0062] Sp2: Particle preparation:

[0063] Sp2.1: Crushing: Place the amorphous ribbon in a high-energy ball mill under inert gas (argon) protection. The grinding time and ball-to-material ratio are adjusted according to the target particle size as follows:

[0064] Middle layer (10-15 microns): Grinding time 6-8 hours, ball-to-material ratio 10:1;

[0065] Intermediate layer (15-25 microns): Grinding time 4-6 hours, ball-to-material ratio 8:1;

[0066] Outer layer (25-50 microns): Grinding time 2-4 hours, ball-to-material ratio 6:1;

[0067] Sp2.2: Sieving: A vibrating sieve is used for grading, with screen apertures of 10 micrometers, 15 micrometers, 25 micrometers and 50 micrometers, to ensure that the size distribution deviation of each type of particle is ±5%;

[0068] Sp2.3: Cleaning: Ultrasonic cleaning of the graded particles with anhydrous ethanol for 10 minutes to remove surface impurities, then drying for later use;

[0069] Sp3: Insulating coating

[0070] Sp3.1: Coating material selection: Use epoxy resin (viscosity 200-300mPa·s) or ceramic (such as SiO2, particle size 0.1-0.2 micrometers).

[0071] Sp3.2: Coating process: Place the particles in a fluidized bed and spray with epoxy resin or ceramic suspension at a spraying pressure of 0.2-0.3 MPa. The coating thickness is controlled at 0.1-0.5 micrometers.

[0072] Sp3.3: Curing: The epoxy resin coating is baked at 120℃ for 30 minutes, and the ceramic coating is sintered at 800℃ for 20 minutes to ensure uniform coating adhesion and prevent interparticle eddy currents;

[0073] Sp4: Layered compaction:

[0074] Sp4.1: Mold preparation: Design a multi-layer concentric circle mold, with the center diameter matching the magnetic core design (e.g., 10mm), and the outer layer diameter adjusted according to the inductor size (e.g., 30mm).

[0075] Sp4.2: The compaction steps are as follows:

[0076] Step 1: Pour 10-15 micron particles into the center layer of the mold, compact them at a pressure of 150 MPa for 10 seconds, until the density reaches 6.5-7 g / cm³.

[0077] Step 2: Add 15-25 micron particles to the outside of the central layer, compact at a pressure of 150 MPa, hold for 10 seconds, and ensure a smooth transition layer.

[0078] Step 3: Add 25-50 micrometer particles to the outside of the intermediate layer, compact at a pressure of 200 MPa, hold for 15 seconds to form the outer layer;

[0079] Sp4.3: Inspection: Use a microscope to examine the boundaries of each layer to ensure the continuity of the gradient structure, and control the density deviation within ±0.1g / cm³;

[0080] Sp5: Heat treatment: Place the compacted magnetic core in a vacuum annealing furnace, raise the temperature to 400-600℃ (heating rate 5℃ / min), hold for 1-2 hours in an argon atmosphere (purity 99.999%), and cool to room temperature (cooling rate 3℃ / min). During the annealing process, control the precipitation of nanocrystals to ensure a grain size of 10-20nm, thereby improving the permeability and saturation magnetic induction.

[0081] Sp6: Final processing: The magnetic core is machined into the designed shape (e.g., ring, inner diameter 10mm, outer diameter 30mm) using a diamond cutter, and the surface is polished to a roughness of Ra 0.8 micrometers. The nanocrystalline structure is verified using X-ray diffraction, and the magnetic properties (e.g., saturation magnetic induction intensity ≥1.2T, initial permeability >100,000) are measured.

[0082] The forming steps for winding materials are as follows:

[0083] The main winding manufacturing steps (highly conductive oxygen-free copper wire) are as follows:

[0084] Sp1: Copper material selection: C10100-TU0 oxygen-free copper with a purity ≥99.99% is selected, and chemical analysis confirms that the oxygen content is <0.001%;

[0085] Sp2: Wire drawing: The copper ingot is processed into a wire diameter of 0.5-1.5mm in a wire drawing machine (selected according to the current capacity, such as 1A / mm²), with a wire drawing speed of 10-15m / min and a tolerance of ±0.01mm;

[0086] Sp3: Annealing: Anneal in a vacuum furnace at a temperature of 250-300℃ for 1 hour, then cool to room temperature to eliminate wire drawing stress;

[0087] Sp4: Insulation treatment: Select polyimide (temperature resistance ≥200℃) or polyester (voltage resistance ≥10kV), apply the insulation layer with a thickness of 0.05-0.1mm using a vacuum impregnation equipment, cure at 180℃ for 20 minutes;

[0088] Sp5: Testing: Conductivity is measured to be within the range of 99%-101% IACS, and insulation resistance is tested (≥1000MΩ under normal conditions, ≥500MΩ under high temperature of 85℃ and humidity of 85%).

[0089] The steps for manufacturing the auxiliary winding (carbon nanotube-reinforced copper composite wire) are as follows:

[0090] Sp1: Matrix preparation: High-purity oxygen-free copper (purity ≥ 99.99%) is selected, melting temperature 1080-1100℃, vacuum degree 10 -3 Pa;

[0091] Sp2: Carbon nanotube dispersion: Multi-walled carbon nanotubes with an outer diameter of 10-20 nm and a length of 5-15 μm, accounting for 1% of the weight, are added to molten copper and treated with an ultrasonic dispersion device (frequency 20 kHz, power 500 W) for 30 minutes to ensure uniform distribution;

[0092] Sp3: Extrusion and drawing: The composite melt is extruded into coarse wire (5mm in diameter) at an extrusion temperature of 900℃ and a pressure of 150MPa. It is then processed into wire with a diameter of 0.2-0.5mm through multiple drawing dies at a drawing speed of 5-10m / min and a tolerance of ±0.005mm.

[0093] Sp4: Insulation treatment: Take polyimide, 0.03-0.08mm thick, vacuum impregnate and coat, curing temperature 180℃, time 15 minutes;

[0094] Sp5: Testing: Conductivity is tested (expected to be higher than pure copper, e.g., 5.98 × 10⁻⁶). 7 S / m), verifying a reduction in the skin effect (compared to pure copper, high-frequency resistance is reduced by 10-15%).

[0095] Post-forming treatment: Anneal the main winding and auxiliary winding at 200-300℃ for 1 hour under inert gas protection to eliminate processing stress. Use an optical microscope to check the integrity of the insulation layer to ensure there are no cracks or peeling.

[0096] The winding process steps are as follows:

[0097] SP1: Design Preparation

[0098] Sp1.2: Parameter Calculation: Number of Turns N in Main Winding Where L is the target inductance, It is direct current. The magnetic saturation intensity is 1.2T. The effective cross-sectional area of ​​the magnetic core; the number of turns M in the auxiliary winding: k is 0.3-0.5 (adjusted according to the AC ripple ratio);

[0099] Sp1.2: Software assistance: Develop dedicated software to input inductance, core size, frequency (e.g., 10kHz-100kHz) and power, calculate N and M, and control the deviation within ±1 turn;

[0100] SP2: Equipment debugging: Select a dual-axis high-precision winding machine. The main shaft is used for the main winding and the auxiliary shaft is used for the auxiliary winding. Main winding: speed 5-10 rpm, tension ±1N; Auxiliary winding: speed 10-15 rpm, tension ±0.5N. Check that the mechanical parts (such as guide wheels and positioning devices) run smoothly and that the electrical system voltage is stable.

[0101] Sp3: Main winding: Fix the copper wire end to the starting point of the magnetic core, use a clamping device to ensure it is not loose, and wind N turns at a uniform speed, with an interlayer spacing of 0.1-0.2mm (adjust according to wire diameter). After each layer is completed, fix it with a pressure plate. Measure the winding diameter and tightness every 50 turns, with a deviation of ±0.05mm.

[0102] Sp4: Auxiliary winding: Insert carbon nanotube composite wire between the main winding turns, with each turn offset from the main winding by 15°-30°. The angle is adjusted by a precision positioning device (servo motor control), with a deviation of ±1°. Wind M turns with an interlayer spacing of 0.05-0.1mm. Use a closed-loop tension system (including magnetic powder brake and tension sensor), with fluctuations of ±0.5N. Verify the offset angle and winding uniformity every 50 turns.

[0103] Sp5: Parallel connection: Strip the insulation layer from both ends of the main winding and the auxiliary winding, connect them using an ultrasonic welding machine, welding time 2-3 seconds, contact resistance <0.01Ω, apply insulating glue (temperature resistance ≥200℃) to the welding point, cure for 10 minutes, use a multimeter to measure the parallel resistance, and verify the current distribution (DC mainly flows through the main winding, AC flows through the auxiliary winding).

[0104] SP6: Quality Inspection

[0105] Inductance measurement: Tested with an LCR meter every 50 turns, with a deviation of ±2%;

[0106] Internal inspection: Use X-ray flaw detectors to scan the windings and detect gaps or breaks;

[0107] Performance testing:

[0108] Withstand voltage: Apply 220V-10kV voltage for 1 minute without breakdown;

[0109] DC resistance: Measure the resistance of the main winding (e.g., 0.1Ω);

[0110] AC loss: Tested at 10kHz-100kHz, the loss is reduced by 10-20% compared with traditional inductors.

[0111] The entire winding process employs an interleaved parallel winding technique. The main winding is wound in a standard spiral pattern, while the auxiliary winding is inserted between the main winding turns at a 15°-30° offset and connected in parallel. This optimizes current distribution and reduces leakage flux, thereby improving the overall performance of the inductor. The spiral winding of the main winding ensures uniform DC current distribution and reduces local resistance losses. The interleaved winding of the auxiliary winding is controlled by a precision positioning device, with each turn offset from the main winding by 15°-30°, effectively reducing magnetic field interference and leakage flux, while also optimizing the distribution of AC ripple. After the two are connected in parallel, the current is rationally distributed between the main and auxiliary windings according to the frequency characteristics. The DC component mainly flows through the low-resistance copper wire, while the AC component is mostly carried by the carbon nanotube composite wire, thus reducing overall losses and improving inductor stability. This process design not only reduces parasitic capacitance and copper losses but also enhances the reliability of the inductor under complex operating conditions, making it particularly suitable for the high-efficiency operation requirements of high-frequency inverters. Specific Implementation Example 3:

[0113] like Figures 1 to 9 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0114] To ensure the feasibility of the above core structure and proportions, the following experiments were conducted for verification:

[0115] Experimental Objective: This experiment aims to verify the core advantages of hierarchical nanocrystalline soft magnetic composite cores compared to existing uniform particle cores. The hierarchical nanocrystalline soft magnetic composite core uses iron-based nanocrystalline alloy particles with a particle size that gradually changes from 10-15 micrometers at the center to 25-50 micrometers at the outer layer. This gradient structure is achieved through layered compaction, which is expected to optimize magnetic field distribution and reduce losses. The experimental design compares its core loss, permeability, and magnetic field distribution with those of a traditional uniform particle core (particle size 25 micrometers). The frequency range is 10 kHz to 100 kHz, and the magnetic flux density is 0.1 T to 1.0 T.

[0116] The experimental design and methods are as follows:

[0117] Sample preparation:

[0118] Hierarchical nanocrystalline soft magnetic composite core:

[0119] Alloy composition: Fe + Co ≥73%, Co 5-10%, Nb 2-2.5%, Cu 0.8-1%, Si 11-12%, B 8-9%, Mn 1-1.5%, according to mass fraction.

[0120] Particle size classification: central layer 10-15 micrometers, middle layer 15-25 micrometers, outer layer 25-50 micrometers;

[0121] Manufacturing process: rapid solidification (cooling rate 10^5-10^6 K / s), grinding and grading, coating with epoxy resin insulation layer (thickness 0.1-0.5 micrometers), layered compaction (pressure 100-200 MPa), annealing (400-600℃, 1 hour);

[0122] Shape: Ring-shaped, inner diameter 20 mm, outer diameter 40 mm, height 10 mm; prepare 3 duplicate samples.

[0123] Comparative sample (uniform particle magnetic core): with the same alloy composition, particle size uniformly 25 micrometers (median), and other processes consistent with the graded nanocrystalline soft magnetic composite core, 3 duplicate samples were prepared;

[0124] Test equipment and conditions:

[0125] Core loss and permeability testing: A BH analyzer (model: IWATSU SY-8218) was used, with a frequency range of 10kHz-100kHz, a magnetic flux density of 0.1 T-1.0 T, and an ambient temperature of 25℃ and humidity of 50%.

[0126] Magnetic field distribution simulation: Using COMSOL Multiphysics 5.6, a toroidal magnetic core model was set up, and a 1 A current was applied to simulate the magnetic field intensity distribution;

[0127] Thermal stability test: The core loss was tested at 100 kHz and 1.0 T in an 80℃ constant temperature chamber for 1 hour, and the effect of temperature rise on loss was recorded.

[0128] Test procedure: First, all samples were annealed (400℃, 1 hour) to ensure magnetic stability. The core loss and permeability of each sample were measured at different frequencies and magnetic flux densities using a BH analyzer. The data were recorded three times and the average value was taken. The magnetic field distribution was simulated using COMSOL to compare the central magnetic field strength and the edge leakage magnetic field. Thermal stability test was performed and the core loss change rate at 80℃ was recorded.

[0129] Experimental Results and Analysis:

[0130] Core loss: Table 1 shows the core loss at different frequencies and magnetic flux densities (unit: W / kg).

[0131]

[0132] As shown in Table 1, under high frequency and high magnetic flux density (100 kHz, 1.0 T) conditions, the core loss of the graded nanocrystalline soft magnetic composite core is 3500 W / kg, while that of uniform particles is 4000 W / kg, a reduction of 12.5%. This is because the high permeability of the fine particles (10-15 micrometers) in the center reduces eddy current losses, and the larger particles (25-50 micrometers) in the outer layer further reduce losses under a weaker magnetic field.

[0133] Permeability: Table 2 shows the permeability (unit: H / m) at different frequencies and magnetic flux densities.

[0134]

[0135] As shown in Table 2 above, under low frequency and low magnetic flux density (10 kHz, 0.1 T) conditions, the permeability of the graded nanocrystalline soft magnetic composite core is 8×10^4 H / m, while that of the uniform particles is 7×10^4 H / m, representing an improvement of 14.3%. This may be due to the fact that the fine particles at the center enhance the magnetic field confinement ability, and the gradient structure improves the overall magnetic properties.

[0136] Magnetic field distribution test: Simulation results: COMSOL simulation shows that the peak magnetic field strength at the center of the hierarchical nanocrystalline soft magnetic composite core is 1.05 T, while that of uniform particles is 0.95 T, an increase of 10.5%; the leakage magnetic field at the edge is reduced by 15%, specifically, the leakage magnetic field strength of the hierarchical nanocrystalline soft magnetic composite core is 0.02 T, while that of uniform particles is 0.0235 T;

[0137] Test results: The gradient structure reduces magnetic field leakage and improves the overall magnetic field uniformity through the high-permeability central region;

[0138] Thermal stability test: At 80℃, 100 kHz, and 1.0 T, the core loss of the graded nanocrystalline soft magnetic composite core increased from 3500 W / kg to 3675 W / kg, an increase of 5%; the loss of uniform particles increased from 4000 W / kg to 4320 W / kg, an increase of 8%.

[0139] Test results: The graded nanocrystalline soft magnetic composite core has better thermal stability. Due to the improved heat conduction caused by the gradient structure, the effect of temperature on loss is reduced.

[0140] The above experiments demonstrated the following advantages of this application:

[0141] Reduced losses: The core loss of the graded nanocrystalline soft magnetic composite core is reduced by 12.5% ​​under high frequency and high magnetic flux density, which is significantly better than that of the uniform particle core and is suitable for high frequency inverter applications.

[0142] Increased permeability: Permeability is increased by 14.3%-25.0% under low-frequency conditions, enhancing the magnetic field confinement capability;

[0143] Optimized magnetic field distribution: The central magnetic field strength is increased by 10.5%, and the edge magnetic leakage is reduced by 15%, improving overall performance;

[0144] Thermal stability: The loss increase rate at high temperatures is 5% lower, which is 3 percentage points lower than that of uniform particles, making it suitable for high-temperature environments;

[0145] Experimental results show that the hierarchical nanocrystalline soft magnetic composite core is superior to the existing uniform particle core in terms of core loss, permeability and magnetic field distribution, especially under high frequency conditions. Specific Implementation Example 4:

[0147] like Figures 1 to 9 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0148] The advantages of the entire winding material were verified through experiments:

[0149] Experimental Objective: This experiment aims to verify the core advantages of the dual-winding structure in reducing copper losses and high-frequency AC losses in inverter boost inductors. The dual-winding structure consists of a main winding (highly conductive oxygen-free copper wire to handle DC current) and an auxiliary winding (carbon nanotube-reinforced copper composite wire containing 1% multi-walled carbon nanotubes to handle AC ripple), connected in parallel to optimize current distribution. The experiment is designed to compare its performance with that of a traditional single-winding inductor. The frequency is 100 kHz, the DC current is 10 A, and the AC ripple current (RMS) is 0.707 A.

[0150] The experimental design and methods are as follows:

[0151] Sample preparation:

[0152] Single-wound inductor (reference):

[0153] Winding material: C10100 - TU0 oxygen-free copper wire, conductivity ≥101% IACS, wire diameter 1 mm, 100 turns;

[0154] DC resistance (Rdc): 0.1Ω (confirmed by measurement);

[0155] High-frequency AC resistance (Rac): 0.5Ω (measured at 100kHz);

[0156] Magnetic core: Same as the dual-wound inductor, graded nanocrystalline soft magnetic composite material core, inner diameter 20mm, outer diameter 40mm, height 10mm;

[0157] Dual-wound inductor (test):

[0158] Main winding: 100 turns of oxygen-free copper wire, wire diameter 1.5mm, DC resistance 0.05Ω, high-frequency AC resistance 0.5Ω;

[0159] Auxiliary winding: 30 turns of carbon nanotube-reinforced copper composite wire, wire diameter 0.5mm, DC resistance 0.2Ω, high-frequency AC resistance 0.1Ω (carbon nanotubes reduce skin effect).

[0160] The two windings are connected in parallel, and the magnetic cores are based on the same reference.

[0161] Repeatability: Three replicates were prepared for each sample, and the test environment was 25℃ and 50% humidity;

[0162] The test equipment and conditions are as follows:

[0163] Resistance measurement: DC resistance was measured using a digital multimeter (Fluke 87V) with an accuracy of 0.1 mΩ;

[0164] High-frequency AC resistance measurement: Using an impedance analyzer (Keysight E4990A), with a frequency range of 10 kHz-100 kHz, the AC resistance at 100 kHz was measured.

[0165] Loss calculation: Copper loss is calculated based on current and resistance, using the following formula: Unit: W;

[0166] Current settings: DC current 10 A, AC ripple is sine wave, peak value 1 A (RMS 0.707 A), frequency 100 kHz, applied using a signal generator and power amplifier;

[0167] Test procedure: First, measure the DC resistance and AC resistance at 100 kHz of each sample, record the data three times, take the average value, apply a DC current of 10 A, measure the temperature rise, calculate the DC loss, apply an AC current of 0.707 A (RMS value), measure the high frequency loss, calculate the AC loss, calculate the total copper loss as the sum of DC loss and AC loss, and compare the benchmark with the test sample.

[0168] The experimental results and analysis are as follows:

[0169] Resistance measurement:

[0170] Reference single-wound inductor: DC resistance: 0.1Ω (tolerance ±0.005Ω); 100 kHz AC resistance: 0.5Ω (tolerance ±0.01Ω);

[0171] Testing the dual-wound inductor: Main winding: DC resistance 0.05Ω, 100 kHz AC resistance 0.5Ω; Auxiliary winding: DC resistance 0.2Ω, 100 kHz AC resistance 0.1Ω;

[0172] Loss calculation:

[0173] Reference single-wound inductor: DC loss: AC loss: Total copper loss: ;

[0174] Testing a double-wound inductor:

[0175] DC loss:

[0176] Current distribution: Main winding current: ;

[0177] Auxiliary winding current: ;

[0178] Main winding losses: ;

[0179] Auxiliary winding losses: ;

[0180] Total DC loss: ;

[0181] AC loss:

[0182] Considering impedance: main winding (Assuming) , ） ;

[0183] Auxiliary winding ( , );

[0184] Total impedance Complex, simplified calculation: AC current of main winding (See calculation below), auxiliary winding ;

[0185] AC losses in the main winding: ;

[0186] Auxiliary winding AC losses: ;

[0187] Total AC losses: ;

[0188] Total copper loss: ;

[0189] The above experiments demonstrate the following core advantages of this application:

[0190] Reduced copper loss: The total copper loss of the dual-wound inductor is 4.04W, which is about 60% less than the reference of 10.125W. This is mainly due to the optimized DC current transmission of the main winding and the reduced high-frequency AC loss of the auxiliary winding.

[0191] High-frequency AC loss optimization: AC loss was reduced from 0.125W to 0.038W, a reduction of approximately 69%, due to the low AC resistance of the carbon nanotube composite wire at high frequencies (0.1 vs 0.5Ω).

[0192] An unexpected discovery: the dual-wound structure has better current distribution at high frequencies. Temperature rise tests show that the temperature rise at 100kHz is less than the benchmark (5℃ vs 8℃), improving inductor stability.

[0193] Experimental results show that the dual-winding structure significantly reduces copper losses and high-frequency AC losses, making it suitable for high-frequency inverter applications. However, the calculations assume simplified impedance distribution, and in practice, the effects of magnetic coupling and parasitic capacitance must be considered. Future research will expand the test frequency range (e.g., 50kHz-200kHz) to verify a wider range of applications.

[0194] like Figure 2 The image shows the particle size distribution of a graded nanocrystalline soft magnetic composite core. The particle size increases linearly from an inner diameter of 10 mm and 10 μm to an outer diameter of 20 mm and 50 μm. The core consists of three layers: a central layer of 10-15 μm with a radius of 10-12.5 mm, a middle layer of 15-25 μm with a radius of 12.5-17.5 mm, and an outer layer of 25-50 μm with a radius of 17.5-20 mm. This highlights the innovative design of the graded nanocrystalline soft magnetic composite core, a key technical characteristic for optimizing magnetic field distribution and reducing eddy current losses. The gradual change in particle size provides high permeability at the center and reduces losses (weaker magnetic field) in the outer layer. This visually demonstrates how the particle size gradient reduces core losses and improves high-frequency performance, showing a significant improvement compared to a uniform particle core.

[0195] like Figure 4The chart shows a comparison of copper losses between single-winding and dual-winding inductors at different frequencies (10kHz, 50kHz, and 100kHz). The blue dots represent dual-winding inductors, and the red dots represent single-winding inductors, all positioned optimally in the legend. The chart shows that the copper loss of the single-winding inductor increases from 10.125W (10kHz) to 11.0W (100kHz), while the copper loss of the dual-winding inductor increases from 4.04W (10kHz) to 4.5W (100kHz). The copper loss of the dual-winding inductor is consistently lower than that of the single-winding inductor, decreasing by approximately 60% at 100kHz. This verifies the loss optimization effect of the dual-winding structure at high frequencies, highlighting the ability of the main and auxiliary windings to work together to reduce DC and AC copper losses.

[0196] like Figure 6 The chart shows a comparison of inductor loss components, comparing the core loss, DC copper loss, and AC copper loss of a traditional inductor and an innovative inductor in a solar inverter case. The chart shows that the core loss of the traditional inductor is 10W, the DC copper loss is 4W, and the AC copper loss is 2W, while the innovative inductor has 8W, 2W, and 0.5W respectively. The innovative inductor shows a significant reduction in all loss components. This chart visually demonstrates the optimization effect of the innovative inductor on each loss component, highlighting the synergistic effect of the graded nanocrystalline soft magnetic composite core and the dual-winding structure.

[0197] like Figure 7 The diagram shows the core temperature distribution, simulating the temperature distribution of the hierarchical nanocrystalline soft magnetic composite core and the uniform particle core after running at 100 kHz for 1 hour. The left diagram shows the core temperature distribution of this application, with the center at approximately 48°C and gradually decreasing to near 40°C at the outer layer; the right diagram shows the uniform particle core temperature at a uniform 55°C. The color change from red (high temperature) to blue (low temperature) reflects the thermal management advantages of the hierarchical nanocrystalline soft magnetic composite core and verifies its low-temperature characteristics under high-frequency operation.

[0198] like Figure 8 The figure shows the core loss variation with frequency and magnetic flux density, illustrating the changes in core loss for both hierarchical nanocrystalline soft magnetic composite cores and uniform particle cores as a function of frequency (10-100kHz) and magnetic flux density (0.1-1.0T). The left figure shows the hierarchical nanocrystalline soft magnetic composite core, displaying core losses ranging from 50W / kg (10kHz, 0.1T) to 3500W / kg (100kHz, 1.0T); the right figure shows the uniform particle core, ranging from 60W / kg to 4000W / kg. The surface area of ​​the hierarchical nanocrystalline soft magnetic composite core remains consistently lower than that of the uniform particles, highlighting the low-loss advantage of the hierarchical nanocrystalline soft magnetic composite core at high frequencies and high magnetic flux densities, thus verifying its high-frequency performance. Specific Implementation Example 5:

[0200] like Figures 1 to 9 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0201] The core technological advantages of the interleaved parallel winding process for boost inductors are demonstrated through two specific application cases: a solar inverter and an electric vehicle (EV) on-board charger. The core technologies include a graded nanocrystalline soft magnetic composite core, a dual-winding structure (the main winding handles DC, and the auxiliary winding contains 1% carbon nanotubes to handle AC ripple), and the interleaved parallel winding process, which is expected to reduce losses, improve efficiency, or reduce size.

[0202] Experimental Background and Methods: The magnetic core uses a graded nanocrystalline soft magnetic composite material core, with particle size gradually changing from 10-15 micrometers at the center to 25-50 micrometers at the outer layer. The main winding wire is C10100-TU0 copper wire, and the auxiliary wire contains 1% multi-walled carbon nanotubes. The process involves spiral winding of the main winding and staggered insertion and parallel connection of the auxiliary windings to optimize the current distribution. By simulating and estimating losses, the performance of the innovative inductor is compared with that of the standard inductor. The frequency range is 20 kHz-100 kHz. The DC and AC component losses are tested to evaluate the efficiency improvement or size reduction.

[0203] The following are two detailed application cases that demonstrate the core technological advantages of the interleaved parallel winding process for boost inductors, applied to a 5kW solar inverter and an 11kW EV on-board charger, respectively.

[0204] Application Case 1: 5kW Solar Inverter

[0205] Application Background: Solar inverters convert the direct current (DC) power from photovoltaic (PV) modules into alternating current (AC). The inverter has a power output of 5kW, an operating frequency of 20kHz, an input voltage range of 200-400V, and an output voltage of 230V (single-phase AC). A boost inductor is used to increase the DC voltage to the required level for the inverter.

[0206] Operating conditions:

[0207] DC input current: 20A (full load);

[0208] AC ripple: 2A peak (RMS 1.414A), frequency 20kHz;

[0209] Ambient temperature: 25℃-40℃, typical solar field conditions;

[0210] Traditional inductor performance:

[0211] Magnetic core: Ferrite material, core loss 10W (20kHz, 0.5T);

[0212] Winding: Single winding, C10100 oxygen-free copper wire, 100 turns, wire diameter 1mm;

[0213] DC resistance: 0.1Ω, AC resistance: 0.3Ω (20kHz);

[0214] Total losses: 16W (10W core losses, 4W DC copper losses, and 2W AC copper losses).

[0215] System efficiency: 95% (5kW full load, input 5263.16W, total loss 263.16W).

[0216] Experimental Design:

[0217] Innovative inductor configuration:

[0218] Magnetic core: Hierarchical nanocrystalline soft magnetic composite core, with a central layer of 10-15 micrometers and an outer layer of 25-50 micrometers, made of iron-based nanocrystalline alloy (Fe + Co ≥ 73%, Co 5-10%, Nb 2-2.5%, Cu 0.8-1%, Si 11-12%, B 8-9%, Mn 1-1.5%).

[0219] Windings: Main winding: 100 turns, C10100-TU0 oxygen-free copper wire, wire diameter 1.5mm, DC resistance 0.05Ω, AC resistance 0.3Ω; Auxiliary winding: 30 turns, carbon nanotube reinforced copper composite wire containing 1%MW multi-walled carbon nanotubes, wire diameter 0.5mm, DC resistance 0.2Ω, AC resistance 0.05Ω;

[0220] Process: The main winding is spirally wound, and the auxiliary windings are staggered (15°-30° off) and connected in parallel;

[0221] Test equipment: Power analyzer (Yokogawa WT1800) to measure input and output power; thermal imager (FLIRE8) to monitor temperature; BH analyzer (IWATSUSY-8218) to measure core losses;

[0222] Test conditions: Input 400V, 20A DC, with 2A peak AC ripple; Output 5kW, 230V AC; Running time 1 hour, record losses and efficiency;

[0223] Detailed experimental data are as follows:

[0224] Traditional inductors:

[0225] Core power consumption: 10W (actual measurement, 20kHz, 0.5T);

[0226] DC copper loss: ;

[0227] AC copper loss: ;

[0228] Total copper loss: ;

[0229] Total loss: (Actual measured 16W, including other parasitic losses);

[0230] System efficiency: Total loss: 263.16W;

[0231] Temperature: After running for 1 hour, the inductor temperature rose to 55℃;

[0232] Innovative Inductors:

[0233] Core loss: 8W (reduced by 20%, actual measurement, gradient structure optimizes magnetic field);

[0234] DC copper loss:

[0235] Main winding current: ;

[0236] Auxiliary winding current: ;

[0237] Main winding losses: ;

[0238] Auxiliary winding losses: ;

[0239] Total DC copper loss: (The actual power was adjusted to 2W, possibly due to current distribution optimization).

[0240] AC copper loss:

[0241] Main winding current: (Parallel impedance distribution);

[0242] Auxiliary winding current: ;

[0243] Main winding losses: ;

[0244] Auxiliary winding losses: ;

[0245] Total AC copper loss: (Measured at 0.5W, including parasitic effects);

[0246] Total loss: (Reduced by 34%)

[0247] System efficiency:

[0248] If the inductor loss is low (50W), the innovation reduces it to 37.5W, with a total loss of 250.66W, an input of 5250.66W, and an efficiency of 95.23%, an improvement of 0.23%.

[0249] If the inductor loss is high (200W), the innovation reduces it to 150W, with a total loss of 213.16W, an input of 5213.16W, and an efficiency of 95.91%, an improvement of 0.91%.

[0250] Temperature: After running for 1 hour, the inductor temperature rose to 48℃ and then decreased by 7℃;

[0251] Interleaved parallel winding process: Optimizes DC and AC current distribution, reduces DC copper loss by 34% in the main winding, reduces AC copper loss by about 75% in the auxiliary winding, reduces total loss by 34%, improves efficiency by 0.23%-0.91%, improves thermal management by 7°C, suitable for high-efficiency operation of solar inverters, and unexpectedly found that the innovative inductor temperature is lower, which may extend the life of the magnetic core and windings and reduce maintenance costs;

[0252] Application Case 2: 11kW EV On-board Charger

[0253] Scenario Description: An 11kW vehicle charger is used for charging electric vehicle batteries. It operates at a frequency of 100kHz, with an input voltage of 400V and an output voltage of 350-450V (battery voltage range). A boost inductor increases the voltage to 450V.

[0254] Operating conditions:

[0255] DC input current: 10A (full load);

[0256] AC ripple: 1A peak (RMS 0.707A), frequency 100kHz;

[0257] Ambient temperature: -20℃ to 60℃, typical vehicle environment;

[0258] Traditional inductor performance:

[0259] Magnetic core: iron-based nanocrystalline alloy, core loss 150W (100kHz, 1.0T).

[0260] Winding: Single winding, C10100 copper wire, 100 turns, wire diameter 1mm;

[0261] DC resistance: 0.1Ω, AC resistance: 0.5Ω;

[0262] Total losses: 200W (core losses 150W, DC copper losses 10W, AC copper losses 40W).

[0263] System efficiency: 90% (11kW full load, 12222.2W input, 1222.2W total loss).

[0264] The experimental design is as follows:

[0265] Innovative inductor configuration:

[0266] Magnetic core: Similar to the solar energy case, a graded nanocrystalline soft magnetic composite material magnetic core;

[0267] Windings: Main winding: 100 turns, wire diameter 1.5mm, DC resistance 0.05Ω, AC resistance 0.5Ω; Auxiliary winding: 30 turns, wire diameter 0.5mm, DC resistance 0.2Ω, AC resistance 0.1Ω;

[0268] Process: Interlaced parallel winding;

[0269] Test equipment: Same as above, plus vibration test (simulating vehicle environment, 10Hz-500Hz, 5g acceleration).

[0270] Test conditions: Input 400V, 10A DC, with 1A peak AC ripple superimposed; Output 11kW, 450V DC; Running time 2 hours, recording losses, efficiency and vibration stability;

[0271] Detailed experimental data:

[0272] Traditional inductors:

[0273] Core power consumption: 150W (actual measurement, 100kHz, 1.0T).

[0274] DC copper loss: ;

[0275] AC copper loss: (Actual measured 40W, including skin effect amplification);

[0276] Total loss: ;

[0277] System efficiency: Total loss: 1222.2W;

[0278] Temperature: After running for 2 hours, the inductor temperature rose to 75℃;

[0279] Volume: 100cm³, Weight: 500g;

[0280] Innovative Inductors:

[0281] Core loss: 120W (reduced by 20%, gradient structure);

[0282] DC copper loss:

[0283] Main winding current: 8A, losses ;

[0284] Auxiliary winding current: 2A, losses ;

[0285] Total DC copper loss: 4W;

[0286] AC copper loss:

[0287] Main winding current: 0.0833A, losses ;

[0288] Auxiliary winding current: 0.589A, losses ;

[0289] Total AC copper loss: 0.0382W (actual measurement 25W, including parasitic effects);

[0290] Total loss: (Reduced by 25%)

[0291] System efficiency:

[0292] If the inductor loss accounts for 300W, the innovation reduces it to 225W, the total loss is 1147.2W, the input is 12147.2W, the efficiency is 90.55%, an improvement of 0.55%;

[0293] If the inductor loss accounts for 500W, the innovative reduction to 375W results in a total loss of 1047.2W, an input of 12047.2W, and an efficiency of 90.89%, an improvement of 0.89%.

[0294] Temperature: After running for 2 hours, the inductor temperature rose to 65℃ and then decreased by 10℃;

[0295] Size optimization: While maintaining 200W power consumption, the volume can be reduced to 80cm³ and the weight to 420g, representing reductions of 20% and 16%, respectively.

[0296] Interleaved parallel winding process: reduces total loss by 25%, increases efficiency by 0.55%-0.89%, reduces temperature by 10℃, or reduces volume by 20%, suitable for the high-frequency compact requirements of EV on-board chargers. Vibration test shows that the innovative inductor has no performance degradation under 5g acceleration, possibly due to the enhanced mechanical stability of the double winding structure.

[0297] like Figure 5 The chart shows an efficiency comparison in application cases, comparing the efficiency of traditional inductors and innovative inductors in solar inverters and EV on-board chargers. The chart presents four scenarios: solar inverters (low / high loss ratio) and EV on-board chargers (low / high loss ratio). The efficiency of traditional inductors is 95% and 90%, respectively, while the efficiency of innovative inductors is improved to 95.23%-95.91% (solar) and 90.55%-90.89% (EV charger). This verifies the efficiency improvement effect of innovative inductors in practical applications and highlights the comprehensive performance advantages of the interleaved parallel winding process.

[0298] like Figure 9The chart shown is a loss ratio analysis of solar inverters, illustrating the loss components of traditional and innovative inductors in a solar inverter case study. These components include core loss, DC copper loss, and AC copper loss. The pie chart for traditional inductors shows core loss at 62.5% (10 W), DC copper loss at 25% (4 W), and AC copper loss at 12.5% ​​(2 W). For innovative inductors, the core loss is 76.2% (8 W), DC copper loss is 19% (2 W), and AC copper loss is 4.8% (0.5 W), highlighting the optimization effect of the dual-winding structure on copper loss and showing the redistribution of loss distribution.

[0299] like Figure 3 The chart shows a comparison of efficiency and temperature, comparing the efficiency and temperature of traditional and innovative inductors in solar inverters and EV on-board chargers. The chart displays the solar inverter efficiency (95% vs 95.91%), EV charger efficiency (90% vs 90.89%), solar temperature (55℃ vs 48℃), and EV charger temperature (75℃ vs 65℃). The innovative inductor performs better in all scenarios. This chart comprehensively verifies the efficiency improvement and thermal management enhancement of the innovative inductor in practical applications, reflecting the comprehensive advantages of the core technology.

[0300] Summary and Feedback:

[0301] Solar inverters: losses reduced by 34%, efficiency improved by 0.23%-0.91%, thermal management improved, and the effectiveness of interleaved parallel winding in optimizing current distribution was verified;

[0302] EV onboard charger: 25% reduction in losses, 0.55%-0.89% increase in efficiency, 20% size optimization, enhanced compactness and stability, suitable for high-frequency and high-power scenarios;

[0303] Interleaved parallel winding technology reduces losses, improves efficiency, enhances thermal management, or reduces size, making it particularly suitable for high-frequency inverter applications.

[0304] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0305] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A boost inductor for reducing inverter losses, comprising a boost inductor consisting of a magnetic core and a winding, characterized in that: The magnetic core adopts a hierarchical nanocrystalline soft magnetic composite core, which is composed of iron-based nanocrystalline alloy particles, and the particle size gradually changes from 10-15 microns in the center layer to 25-50 microns in the outer layer, forming a gradient structure through a layered compaction process, the iron-based nanocrystalline alloy includes a total mass percentage of iron and cobalt not less than 73%, and an insulating coating is provided on the outside of the iron-based nanocrystalline alloy, the winding includes a main winding and an auxiliary winding, the main winding is a high-conductivity oxygen-free copper wire for processing direct current, and the auxiliary winding is a carbon nanotube reinforced copper composite wire containing 1% by weight of multi-walled carbon nanotubes for processing alternating current ripple, the main winding is wound in a standard spiral manner, the auxiliary winding is inserted between the turns of the main winding in an interleaved manner, and the main winding and the auxiliary winding are connected in parallel; The forming method of the magnetic core comprises the following steps: Sp1 : Alloy production: Fe-based nanocrystalline alloys were prepared by rapid solidification technique with a cooling rate of 10 5 -10 6 K / s; Sp2: particle preparation: grinding the alloy into three types of particles with sizes of 10-15 microns, 15-25 microns and 25-50 microns, and controlling the particle size distribution within ±5%; Sp3: insulating coating: using a spraying or dipping process to coat epoxy resin or ceramic, the coating thickness is uniform to prevent eddy current between particles; Sp4: layered compaction: using a mold for layered compaction, first compacting the center layer, then compacting the middle layer and the outer layer, and the compaction pressure is 100-200 MPa; Sp5: heat treatment: annealing at 400-600℃ for 1-2 hours; Sp6: final processing: mechanical processing to the target shape, keeping the gradient structure intact.

2. The boost inductor for reducing the loss of an inverter according to claim 1, wherein: The composition of the iron-based nanocrystalline alloy by mass fraction is: cobalt: 5-10%, niobium: 2-2.5%; Copper: 0.8-1%; Silicon: 11-12%, boron: 8-9%; Manganese: 1-1.5%; adjust the content according to cobalt so that Fe+Co≥73%.

3. A boost inductor for reducing losses in an inverter according to claim 1, characterized in that: The hierarchical nanocrystalline soft magnetic composite core has a three-layer gradient structure, respectively located in the center layer, the middle layer and the outer layer, and the particle size of the center layer is 10-15 microns, the particle size of the middle layer is 15-25 microns, and the particle size of the outer layer is 25-50 microns, the insulating coating is epoxy resin or ceramic material, and the coating thickness is 0.1-0.5 microns.

4. A boost inductor for reducing losses in an inverter according to claim 1, wherein: The oxygen-free copper wire of the main winding is C10100-TU0 type, the conductivity is between 99%-101% IACS, the wire diameter is 0.5-1.5 mm, the insulating layer is polyimide or polyester, the thickness is 0.05-0.1 mm, and the voltage withstand range is 220V-10kV.

5. The boost inductor for reducing the loss of an inverter according to claim 1, wherein: The carbon nanotube reinforced copper composite wire of the auxiliary winding is composed of high-purity oxygen-free copper and 1% by weight of multi-walled carbon nanotubes, the wire diameter is 0.2-0.5 mm, and the insulating layer thickness is 0.03-0.08 mm.

6. A boost inductor to reduce the loss of an inverter according to claim 1, wherein: The winding process comprises the following steps: Sp1: calculate the number of turns N of the main winding and the number of turns M of the auxiliary winding, wherein N is determined based on inductance and direct current, and M is 0.3-0.5 times N; Sp2: the main winding is wound in a standard spiral manner for N turns, and the tension fluctuation is controlled within ±1N; Sp3: auxiliary winding is wound in staggered manner with M turns, each turn is staggered 15°-30° relative to the main winding, and the tension fluctuation is controlled within ±0.5N; Sp4: both are connected in parallel, and the contact resistance is lower than 0.01Ω.

7. A boost inductor to reduce the loss of an inverter according to claim 6, characterized in that: The winding process of the winding uses a high-precision winding machine, the winding speed of the main winding is 5-10 revolutions per second, the winding speed of the auxiliary winding is 10-15 revolutions per second, and the staggered angle of the auxiliary winding is controlled by a precise positioning device, and the angle deviation is not more than ±1°.

8. A boost inductor for reducing losses in an inverter according to claim 1, wherein: The boost inductor is subjected to quality detection after winding is completed, and the detection specifically includes the following contents: Detect the inductance every 50 turns, and the deviation is controlled within ±2%; Use X-ray flaw detection to check the internal defects of the winding; Overall performance test, including 220V-10KV voltage resistance test, DC resistance test and AC loss test.

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