CN111584226B - Production process of PFC differential mode inductance magnetic ring - Google Patents
Production process of PFC differential mode inductance magnetic ring Download PDFInfo
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- H01—ELECTRIC ELEMENTS
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- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
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- H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
- H01F41/022—Manufacturing of magnetic circuits made from strip(s) or ribbon(s) by winding the strips or ribbons around a coil
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- H01F13/00—Apparatus or processes for magnetising or demagnetising
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- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
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- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
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- H—ELECTRICITY
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- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
- H01F41/0226—Manufacturing of magnetic circuits made from strip(s) or ribbon(s) from amorphous ribbons
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- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
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- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
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Abstract
The invention relates to a production process of a PFC differential mode inductance magnetic ring, which comprises the following steps: winding a strip, annealing an iron core, solidifying the iron core, cutting an air gap, processing the air gap and spraying; the process can manufacture the iron core of the inductor by the existing amorphous alloy, can improve the production efficiency of the iron core of the inductor, effectively reduces the defective rate of the integrated inductor, and effectively ensures the performance of the integrated inductor, thereby reducing the production and processing cost of the integrated inductor and having good economic and social benefits.
Description
Technical Field
The invention relates to the technical field of inductance magnetic ring production, in particular to a production process of a PFC differential-mode inductance magnetic ring.
Background
In the power supply process of the power system, a large number of power supply and utilization equipment with nonlinear impedance characteristics exist, so that the actual alternating current waveform deviates from the sine wave in an ideal state, and the phenomenon is called sine waveform distortion. The non-sinusoidal wave in this case is a periodic electrical quantity, and can be decomposed into a fundamental component and a harmonic component having an integral multiple of the fundamental frequency (power frequency) by fourier series analysis. Harmonics are actually a disturbing quantity, polluting the grid.
The grid harmonics come from three aspects:
firstly, the power generation quality is not high and harmonic waves are generated: because the three-phase winding of the generator is difficult to be absolutely symmetrical in manufacturing, the iron core is also difficult to be absolutely uniform and consistent, and for other reasons, the generation source can generate some harmonic waves, but generally the generation source is few.
Secondly, the power transmission and distribution system generates harmonic waves: the power transmission and distribution system mainly generates harmonic waves by a power transformer. Because of the saturation of the transformer iron core and the nonlinearity of the magnetization curve, the economical efficiency is considered when the transformer is designed, and the working magnetic density is selected on the nearly saturated section of the magnetization curve, so that the magnetic ring current presents a sharp-top waveform and contains odd harmonics. Its size is related to the structural form of the magnetic circuit and the saturation degree of the iron core. The higher the saturation degree of the iron core is, the farther the working point of the transformer deviates from linearity, and the larger the harmonic current is, wherein the third harmonic current can reach 0.5 percent of the rated current.
Third, harmonic waves generated by electric equipment: a thyristor rectification device. Thyristor rectification is increasingly widely used in electric locomotives, aluminum electrolysis cells, charging devices, switching power supplies and other aspects, and a large amount of harmonic waves are injected into a power grid. The network voltage is coupled with a plurality of burrs or spikes, and even waveform defects and distortions are generated. And the total power factor of the power grid is reduced. It is known that thyristor rectifiers use phase-shift control, absorbing a missing-corner sine wave from the grid, leaving another portion of the missing-corner sine wave to the grid, obviously containing a large number of harmonics in the remaining portion. If the rectifying device is a single-phase rectifying circuit, odd harmonic current is contained when an inductive load is connected, wherein the content of 3-order harmonic can reach 30% of the fundamental wave; when the capacitive load is connected, the capacitive load contains odd harmonic voltage, and the harmonic content of the odd harmonic voltage increases along with the increase of the capacitance value. If the rectifying device is a three-phase fully-controlled bridge 6-pulse rectifier, the primary side of the transformer and a power supply line contain odd harmonic current for 5 times or more; in the case of a 12-pulse rectifier, there is also an odd harmonic current of order 11 and above. Statistics show that: the harmonics produced by the rectifying means account for nearly 40% of all harmonics, which is the largest source of harmonics.
In the three-phase four-wire system power supply system, the neutral current is increased due to the increase of multiple harmonic components, which is a troublesome problem. At present, computer power supplies UPS, program controlled exchanger power supplies, electric welding machine power supplies, electronic ballasts and the like are high-frequency, and pollution to a power grid is obvious and very prominent. Harmonic pollution is a public nuisance of the power grid, which not only causes the loss of electric energy, but also shortens the service life of the used electric equipment, reduces the product quality and further causes great economic loss.
One of the most effective methods for reducing the grid pollution is to add a Power Factor Correction (PFC) function in a circuit. The English of PFC is called Power Factor Correction, which can improve the utility ratio of the Power supply to the commercial Power when AC is converted into DC, reduce the electric energy loss in the conversion process and achieve the purpose of energy saving. In addition, the PFC can reduce the interference of the power supply to the mains grid, in particular avoiding its impact on other appliances at a sudden start. Power correction factors have become a hotspot and key to the market entry of merchants. Power factor correction techniques are becoming more and more widely used and a wide range of power supply workers wish to find suitable materials to meet the requirements of electrical circuits. At present, inductance materials used in a PFC circuit comprise ferrite, silicon steel sheets, iron-based amorphous and magnetic powder cores (the magnetic powder cores comprise iron powder cores, FeSi, FeSiAl and permalloy powder cores), and all the materials have advantages and disadvantages, the loss of the ferrite is the lowest, but the volume is the largest. The eddy current loss of the silicon steel sheet is large at high frequency. Ferrosilicon has the best bias current characteristics but the highest losses. Sendust has less bias current characteristics than sendust, but losses are better than sendust. The iron-based amorphous alloy material has an amorphous special structure, high saturation magnetic induction strength (Bs/saturation Flux Density, which can reach 1.64T), high Resistivity (rho/Eleca Trical resistance 130 mu omega-cm) and low loss (the thickness of the material is about 303m, so that the eddy current loss is small during high-frequency operation), and is an ideal green energy-saving environment-friendly material.
The input side of the frequency converter is connected with a proper reactor in series or provided with a harmonic filter, and the filter and a capacitor form an LC filter circuit to absorb harmonic waves and increase the impedance of a power supply or a load, so that the aim of inhibiting the harmonic waves is fulfilled.
As shown in fig. 1, in the differential mode inductor circuit, the differential mode inductors L1 and L2 are connected in series with the X capacitor to form a loop, because the inductance of L1 and L2 to the differential mode high frequency interference is large, and the capacitance of the X capacitor C1 to the high frequency interference is small, the differential mode interference noise is filtered out, so that the differential mode interference noise cannot be added to the following circuit, and the purpose of suppressing the differential mode high frequency interference noise is achieved.
The iron core in the differential mode inductor is made of the iron-based amorphous alloy material, which is a technical problem to be solved urgently at present.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a production process of a PFC differential mode inductance magnetic ring.
In order to achieve the purpose, the invention adopts the following technical scheme, a production process of the PFC differential mode inductance magnetic ring,
winding the strip material: processing the selected iron-based amorphous belt through an iron core automatic winding machine according to the designed size of the iron core;
iron core annealing: putting the processed and molded iron core into a vacuum furnace, heating under the protection of nitrogen, and preserving heat for 40-75 minutes when the heating temperature reaches 370-380 ℃; then, the iron core is lifted out of the vacuum furnace for cooling, and the iron core annealing process is completed;
and (3) iron core solidification: mixing epoxy resin and a curing accelerator, pouring the mixture into a vacuum tank in a vacuum impregnator, putting the annealed iron core into the vacuum tank in the vacuum impregnator for iron core curing, and then putting the cured iron core into an oven for drying;
cutting an air gap: precisely cutting the cured iron core according to the designed air gap value;
air gap treatment: inserting an epoxy plate into the air gap of the core cut;
spraying: and carrying out insulating spraying on the iron core subjected to air gap treatment.
And magnetizing the annealed iron core, wherein the field intensity of the magnetized iron core is 1400A/m-2000A/m.
The iron core annealing is carried out according to the following method:
sequentially penetrating the wound iron cores on the stainless steel pipe, and overlapping;
hoisting the stainless steel pipe with the iron core into a vacuum furnace, and starting a vacuum pump to vacuumize the vacuum furnace;
starting heating, and recording time and ambient temperature;
injecting nitrogen into the vacuum furnace, closing a nitrogen valve when the pressure in the vacuum furnace is increased to be 0.1Mpa greater than the standard atmospheric pressure, starting to record the temperature of the test point, and recording once every 15 minutes;
starting a magnetizing current; when the temperature of at least 50% of the iron core temperature test points reaches 370-380 ℃, carrying out heat preservation for 40-75 minutes;
and after the heat preservation time is up, opening an air release valve of the annealing furnace, opening a furnace cover when the pressure in the furnace is reduced to the normal pressure state, and lifting the iron core out by a crane to cool down to finish the annealing process.
The iron core curing is carried out according to the following method:
mixing epoxy resin and a curing accelerator according to a ratio of 5:6, pouring the mixed epoxy resin and the curing accelerator into a vacuum tank of a vacuum impregnator, and fully stirring;
immersing the whole material placing tray for placing the annealed iron core into a vacuum tank to enable the whole iron core to be submerged below the liquid level;
closing the upper cover, the blow-down valve and the air release valve of the vacuum tank, opening a vacuum pump valve and a vacuum pump, pumping out air in the tank, and when the vacuum pressure gauge stops, the vacuum tank is nearly in a vacuum state;
keeping the vacuum state for 10 minutes to ensure that the iron core is fully contacted with the curing agent;
opening an air release valve after 10 minutes, opening a tank cover when the air pressure of the vacuum tank is recovered to normal pressure, and taking out the iron core to be fully drained;
if the outside air temperature is low, the curing agent adhered to the surface of the iron core is in a viscous state, and the curing agent is quickly drained by low-temperature baking;
then putting the tray into an oven for baking; and during baking, adjusting the heating speed of the oven to heat to 393K at 3K/min, preserving the heat for 360min, and taking out the iron core.
The spraying is carried out according to the following method:
preparation before spraying: opening the tunnel heating furnace, and setting the furnace temperature; then opening an air compressor switch, firstly emptying the water at the bottom, and then starting up the air compressor to operate; paying attention to the air pressure condition, and setting the pressure to be 8 KG; turning on a power supply of a spraying cabinet of the coating machine; checking the spray gun, wherein the powder in the powder barrel is sufficient;
setting parameters of a spraying machine: turning on a power control switch, setting the temperature of the area I to be 180 ℃, setting the temperature of the area II to be 180 ℃, and setting the temperature of the area III to be 180 ℃; starting a heating program, turning on the hot air circulating machine, after 45 minutes, raising the temperature to a set value, turning on a chain motor switch, setting the rotating speed to be 4HZ, turning on a power supply of a tray grabbing manipulator, setting the mode to be an automatic mode, and finally turning on an operation screen switch of the electrostatic spraying machine to enter the setting of a spraying program;
setting a spraying program: starting a PLC operation program, turning on power illumination, and setting the running track of the spray gun;
starting an exhaust fan switch, setting the speed to be about 30HZ, the XY speed to be 400-; the high-voltage electrostatic powder spraying has the air pressure of 2-4KG, the atomization of 0.1-0.2 and the voltage of 50-65 KV;
iron core spraying: placing the insulating powder in a fluidization barrel, adjusting the air pressure to be 0.2MPA, starting vibration, and performing iron core electrostatic spraying;
baking: the iron cores are placed in the tray and evenly placed; putting the material tray back to the heating furnace for baking for 15 minutes; and finishing the baking of the iron core.
The method also comprises the step of detecting the iron core after spraying, wherein the detection comprises the step of detecting the no-load inductance, the direct-current superposed inductance, the power loss, the direct-current resistance, the insulation resistance, the turn-to-turn voltage resistance and the voltage resistance of the iron core.
The invention has the beneficial effects that: the process can manufacture the iron core of the inductor by the existing amorphous alloy, can improve the production efficiency of the iron core of the inductor, effectively reduces the defective rate of the integrated inductor, and effectively ensures the performance of the integrated inductor, thereby reducing the production and processing cost of the integrated inductor and having good economic and social benefits.
Drawings
FIG. 1 is a schematic diagram of a differential mode inductor in the prior art;
FIG. 2 is a block diagram of the production process of the present invention;
FIG. 3 is a schematic view of an annealing curve in the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and examples.
In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of the present invention, "a plurality" means two or more unless otherwise specified.
Example 1
Figure 2 shows a process for producing a PFC differential mode inductance magnetic ring,
winding the strip material: processing the selected iron-based amorphous belt through an iron core automatic winding machine according to the designed size of the iron core;
in the embodiment, the iron-based amorphous strip is made of a 1K101 iron-based amorphous strip, and an iron core automatic winding machine is used for equipment;
because of the requirements on space and application environment in the use process of the inductance coil, the length, the width and the height of the inductance coil are specified in the appearance size of a product, namely after assembly; therefore, the iron core is relatively provided with manufacturing standards of inner diameter, outer diameter and thickness; the inner diameter of the iron core depends on the outer diameter of the winding shaft, and the winding height, namely the outer diameter of the iron core, is adjusted after the specified winding shaft is selected to be installed according to the size requirement of a product; and (4) adjusting the winding thickness according to the inner and outer diameter size (winding thickness: 1/2 (outer diameter of the magnetic core-inner diameter of the magnetic core)) of the required product. After trial winding, fine adjustment is carried out on the winding thickness according to the actual thickness of the product, so that the required outer diameter size of the magnetic core is achieved;
taking product HH301615 as an example, the dimensional specifications of the iron core are: phi 30 phi 16 phi 15, namely selecting a shaft with the diameter phi 16, and adjusting the winding thickness to 1/2 phi (30-16) to 7 mm; after the shaft is installed, the distance between the horizontal top end of the shaft and the limiting stopper is 7 mm; and selecting an iron-based amorphous strip with the thickness of 15mm, and normally operating after the equipment is debugged.
In order to prevent the defects of the appearance size of the iron core caused by the strip abnormality, the inner and outer diameter sizes and the iron core height are monitored by cooperating with visual observation by taking the weight of a single iron core as a reference.
And (3) control points: core outside diameter, core inside diameter, height, weight.
Iron core annealing: putting the processed and molded iron core into a vacuum furnace, heating under the protection of nitrogen, and preserving heat for 40-75 minutes when the heating temperature reaches 370-380 ℃; then, the iron core is lifted out of the vacuum furnace for cooling, and the iron core annealing process is completed;
the treatment annealing process is the most critical and difficult-to-control process in the whole manufacturing process of the amorphous alloy iron core, and the related process elements are the most, including atmosphere protection, annealing temperature point, heating rate, cooling rate, heat preservation time, size of a direct-current magnetic field, furnace condition requirements of an annealing furnace and the like.
Atmosphere protection
The amorphous alloy strip is an iron-based alloy material, and the iron component accounts for more than 90%. Therefore, the iron core is easily oxidized by the influence of temperature and humidity during high-temperature heat treatment annealing; after the surface of the iron core is oxidized, besides the surface has rusts, the surface oxide layer can cause the no-load loss of the iron core to be obviously increased; therefore, the iron core must adopt atmosphere protection in the whole annealing process of heat treatment to reduce and prevent the surface of the iron core from being oxidized; the commonly used process protective gas at present is nitrogen or argon, and the purity of the protective gas can be selected according to local climate environment, humidity condition and the like; in consideration of production cost, 98% industrial nitrogen is adopted for protection at present.
Temperature rising and temperature lowering rates
The temperature rise speed and the temperature drop speed of the amorphous alloy iron core also have important influence on the performance of the iron core; because the iron cores are subjected to multiple loading and batch heat treatment during batch production, the reasonable temperature rise and temperature fall speed not only influences the performance result of the iron cores, but also influences the production efficiency and the production cost; the temperature rise speed can affect the temperature discreteness of the amorphous alloy iron core with the same heat, and can also affect the discreteness of the performance of the iron core; the faster the temperature rise speed is, the greater the discreteness is; compared with the conditions of the domestic and imported amorphous alloy strip iron cores in the temperature rising process, the temperature discreteness of the imported amorphous strip iron core at the low-temperature section is smaller, but the temperature discreteness is increased when the imported amorphous strip iron core reaches the high-temperature section; the temperature dispersion of the domestic amorphous alloy strip iron core is smaller when the domestic amorphous alloy strip iron core reaches a high-temperature region and approaches to an optimal annealing temperature point, and the temperature dispersion can be almost controlled within 3 ℃; therefore, in the temperature rise stage, the domestic amorphous alloy strip iron core can be directly subjected to rapid temperature rise, and the imported amorphous alloy strip iron core needs to adopt a process of eliminating temperature difference, namely, slowly raising the temperature; the cooling speed also directly influences the internal performance of the iron core; the test proves that: the cooling speed is high, which is beneficial to reducing the no-load loss of the iron core, but can increase the excitation power of the iron core; therefore, the optimum cooling speed of the domestic amorphous alloy strip iron core needs to be selected according to the characteristics of heat treatment equipment and the finally achieved performance index of the iron core.
DC magnetic field
The magnetic property of the formed amorphous alloy iron core needs to be improved by adding a direct-current magnetic field during annealing; the principle is as follows: placing the amorphous alloy iron core in a magnetic field along the direction of the strip to cause the magnetic domain arrangement of the uniaxial anisotropy of the amorphous alloy strip so as to obtain good magnetic domain orientation; the magnitude of the field intensity is the key for improving the magnetic property of the amorphous alloy iron core; when the adopted field intensity is larger than the minimum saturation value of the magnetic property of the amorphous alloy iron core material, the magnetic field can not generate beneficial or harmful effects on the final magnetic property of the iron core; therefore, the field intensity commonly used in the iron core annealing process is consistent with or slightly larger than the saturation value of the magnetic property of the amorphous alloy material; because of different components, electromagnetic properties and the like, the field intensity difference between the iron core of the amorphous alloy strip made in China and the iron core of the imported amorphous alloy strip is obvious when the iron core is annealed; the test shows that: the field intensity of the inlet amorphous alloy strip iron core during annealing is 800A/m or the magnitude of magnetic field current is 500-800A, so that the iron core material can be saturated during annealing; the field intensity of the iron core of the domestic amorphous alloy strip needs about 2000A/m during annealing, or the iron core material can be saturated during annealing when the magnetic field current is 1400A, so that the optimal annealing effect can be achieved.
Particularly, during processing, the adopted equipment is a nitrogen protective furnace;
the iron core formed by winding sequentially penetrates through a 304 stainless steel pipe, the length of the steel pipe is 75cm, and the iron core and the steel pipe are overlapped. Then inserting the steel pipe into the annealing frame base, hoisting the steel pipe into the furnace, and closing the furnace cover; opening a vacuum pump, and vacuumizing the annealing furnace; starting heating, and recording time and ambient temperature; injecting nitrogen into the vacuum furnace, closing a nitrogen valve when the pressure in the vacuum furnace is increased to be 0.1Mpa more than the standard atmospheric pressure, starting to record the temperature of the test point as shown in figure 3, and recording every 15 minutes; starting a magnetizing current; when the temperature of at least 50% of the iron core temperature test points reaches 370-380 ℃, carrying out heat preservation for 40-75 minutes; and after the heat preservation time is up, opening an air release valve of the annealing furnace, opening a furnace cover when the pressure in the furnace is reduced to the normal pressure state, and lifting the iron core out by a crane to cool down to finish the annealing process.
And (3) iron core solidification: mixing epoxy resin and a curing accelerator, pouring the mixture into a vacuum tank in a vacuum impregnator, putting the annealed iron core into the vacuum tank of the vacuum impregnator for iron core curing, and then putting the cured iron core into an oven for drying;
the iron core after annealing is solidified so as to shape the iron core, thereby facilitating subsequent breath cutting and epoxy powder spraying on the surface of the iron core; the conventional iron core dipping and curing process has the problem that the iron core is stressed due to the curing shrinkage of a dipping material, so that the performance is greatly reduced; of course, if the inductance of the iron core is far higher than the technical requirement in design, the resistivity between the iron core laminations can be greatly improved by fully soaking the iron core, and although the inductance is reduced, the eddy current loss of the iron core can be obviously reduced;
the iron core needs more than 24 hours for complete curing under natural conditions, and in order to reduce cost and improve production efficiency, the curing is accelerated in a baking mode in actual production; the analysis considers that: the stress generated by curing shrinkage is increased along with the increase of the curing temperature, among various factors influencing the curing system, the influence of the curing temperature is the largest, and when the curing is carried out at the temperature of 393K, the shrinkage stress is the smallest, the influence on the iron core is the smallest; test results show that the soft magnetic performance of the iron core is deteriorated after being dipped in paint, wherein the influence of the curing temperature is the largest, the heating rate is the second, and the influence of the curing time is the smallest; when the temperature is raised to 393K at the rate of 3K/min and is kept for 360min, the paint-dipped iron core has the most excellent soft magnetic performance which is mainly related to the internal stress of glue solution curing shrinkage; at this time, the loss at 1kHz/1T was increased by 20.7%, the single-turn inductance at 10kHz/1V was decreased by 2.6%, and the magnetic induction B800(800A/m) was decreased by 7.1%.
In order to reduce the stress generated to the iron core in the curing process, reduce the loss, improve the physical property and the mechanical strength of the iron core and obtain an accurate and beautiful appearance; the curing agents we currently used are epoxy resin E1228MR and cure accelerator E1228 MH.
The equipment adopted by the iron core curing is a vacuum impregnator and a baking oven;
specifically, during curing, the epoxy resin E1228MR and the curing accelerator E1228MH are mixed according to the ratio of 5:6, poured into a vacuum tank and fully and uniformly stirred; and then, immersing the whole material placing tray for placing the annealed iron core into a vacuum tank to enable the whole iron core to be submerged below the liquid level. Closing the upper cover, the blow-down valve and the air release valve of the vacuum tank, opening the valve of the vacuum pump and the vacuum pump, pumping out air in the tank, and when the vacuum pressure gauge stops, the vacuum tank is nearly in a vacuum state. The vacuum state is kept for 10 minutes, and the iron core is fully contacted with the curing agent. And opening the air release valve after 10 minutes, opening the tank cover when the air pressure of the vacuum tank is recovered to normal pressure, taking out the iron core, and fully draining. If the outside air temperature is low, the curing agent adhered to the surface of the iron core is in a viscous state, and a low-temperature baking method (below 35 ℃) can be adopted to promote the curing agent to be quickly drained; because the surface of the iron core is adhered with the curing agent, the iron core has high adhesive force after being contacted and cured with the metal surface or the surface of ceramics, glass or other hard materials, the iron core is required to be independently placed on cloth and other fabrics with rough surfaces before curing and baking; the cloth can be flatly laid in the material placing disc, and the impregnated iron core is placed in the material placing disc; the iron cores are spaced from each other when placed, and are not adhered; then putting the tray into an oven for baking; during baking, the temperature of the oven is adjusted to 393K (about 120 ℃) at the heating speed of 3K/min, and the iron core is taken out after heat preservation is carried out for 360 min.
Cutting an air gap: precisely cutting the cured iron core according to the designed air gap value;
air-gap cores are widely used in electromagnetic components; the air gap can avoid the magnetic saturation phenomenon under the condition of alternating current large signals or direct current bias, and the inductance value can be better controlled; the air gap is formed on the iron core, so that the original characteristics of the iron core are not influenced, and the working magnetic flux density and saturation magnetic flux density are increased; and secondly, the opening air gap of the iron core is mainly used for reducing the residual magnetism of the iron core when the iron core works in an asymmetric magnetic field state, and the larger the air gap is, the smaller the residual magnetism of the iron core is when the coil current is reduced to zero, so that the iron core with the same volume can output larger power.
However, the larger the air gap is, the smaller the inductance coefficient of the iron core is, more coils need to be wound to achieve a certain inductance, the related copper loss is increased, and the distributed capacitance with more coil turns is relatively increased, which affects the working stability of the electromagnetic element, so many tradeoffs are needed in practical application, and the optimal value of the air gap size is determined.
The size of the air gap can be calculated by the number of turns (N) of the iron core winding, the effective sectional area (Ae) and the direct current superposition inductance (L).
GAP＝4×π×Ae×N^2/(L×10^8)
Wherein, the unit of Ae is cm ^2, the unit of L is H, and the unit of GAP is mm.
The equipment used for cutting the air gap is an AKE-350 precision cutting machine and a cutting blade;
specifically, iron cores are closely arranged together, the number of the iron cores is determined according to the length of the supports, and the central line of the iron cores is kept parallel to the two supports when the iron cores are placed; the iron core is tightly fixed by a clamp, so that the iron core is ensured not to shake in the cutting process; the nozzle position of the cooling liquid is adjusted, so that the iron core is completely surrounded by the cooling liquid in the cutting process, particularly the knife edge position, if the cutting blade cannot be cooled in time in the cutting process, the service life of the cutting blade is influenced, the appearance of the cutting blade is poor, and even the product performance is fatally damaged.
After the cutting piece is installed, the power supply of the equipment is started, the starting point position and the rotating speed, the stroke and the horizontal advancing speed are set on the equipment controller, the rotating speed and the advancing speed must be properly adjusted according to the quality of a cutting air gap, the situation that no edge warping, layering, burrs and surface defects exist around the air gap after cutting is guaranteed, and a cutting surface is flat and smooth.
After the first piece confirms that no quality problem exists, the equipment can normally operate; in the running process of the equipment, whether each part of the equipment is in a normal running state or not is checked in time through the observation port, once abnormity occurs, the running is stopped immediately, and the operation can be continued after recovery; and after the air gap is cut, putting the iron core into clean cutting fluid for washing, and ensuring that no iron scraps are left between the surface of the iron core and the air gap. Taking out and drying at low temperature or naturally airing.
Air gap treatment: inserting an epoxy plate into the air gap of the core cut;
the reason is as follows: after the cutting of the iron core air gap is finished, scrap iron and dirt between the iron core surface and the air gap need to be cleaned, and the influence on the product performance caused by surface oxidation in the later use process is prevented; then the iron core can be arranged in a protective box to be used as a magnetic ring to start winding operation; in order to reduce the volume of a product, save materials, reduce the cost and realize the miniaturization of the product, the appearance of the product is processed by adopting an epoxy powder spraying mode, so that the method for treating the air gap of the iron core is particularly important; the original air gap is reserved, and the iron core can leave a dent at the original air gap after being sprayed, so that the appearance is influenced; after the air gap is processed, the appearance of the iron core forms the same structure, and the appearance is smooth after spraying, so that the subsequent winding operation is more favorably carried out.
Specifically, when the method is implemented, the capacity expander is started to perform air gap treatment;
the iron core is placed on the expansion machine, the inner wall of the iron core penetrates through the expansion machine telescopic clamp, the electromagnetic switch is stepped on, after the clamp is extended, the epoxy plate inserting piece is clamped by a clamp and placed between air gaps of the iron core, the electromagnetic switch is loosened, the clamp automatically contracts, and the iron core naturally clamps and fixes the inserting piece after being restored to the original state by elasticity.
During operation, the air valve is firstly used for adjusting the air flow to adjust the maximum position of the clamp, which can be extended, so that the increase of air gaps and appearance deformation caused by the fact that the iron core exceeds the elastic deformation range are avoided. When the inserting sheet is placed, the four sides of the inserting sheet cannot protrude out of the upper surface, the lower surface and the side surfaces of the inner wall and the outer wall of the iron core; the manual bench clamp is loaded with the insert and operated according to the same method; and after the operation is finished, the iron cores are orderly stacked in the tray.
Spraying: and carrying out insulating spraying on the iron core subjected to air gap treatment.
The amorphous iron core spraying process is implemented to replace the assembly of a protective box, so that the appearance of a product is firmer and more attractive, the volume of the iron core is reduced, and correspondingly, the using amount of wires is reduced.
Meanwhile, the reduction of the volume of the whole device saves the limited space and advances one step towards the goals of miniaturization, integration and multi-functionalization of electronic equipment; the spray powder is a thermosetting epoxy resin mixture, is a mixed material consisting of epoxy resin, dicyandiamide, superfine silicon powder and other auxiliary agents, can be softened or flowed in the molding process, has plasticity, is coated on the surface of a product by an electrostatic spraying process at the temperature of 180-190 ℃, and is crosslinked and cured by chemical reaction.
The process has the advantages of cleanness, zero VOC (volatile organic compound) release, convenience for assembly line operation, strong bonding force, high temperature resistance, humidity resistance, excellent electrical insulation performance and the like, and has high-quality coating effect and high-efficiency utilization rate.
Specifically, when spraying is carried out, the adopted equipment is a heating tunnel furnace, an electrostatic reciprocating coating machine and a fluidized bed;
when spraying, setting the parameters of a spraying machine: and turning on a power control switch, setting the temperature of the first zone to be 180 ℃, and setting the temperature of the second zone to be 180 ℃. Setting the area III to be 180 ℃, pressing a green heating key, starting a heating program, turning on the hot air circulating machine, waiting for 45 minutes approximately, increasing the temperature to a set value, turning on a chain motor switch, paying attention to the forward and reverse rotation direction, setting the rotation speed to be 4HZ, turning on a power supply of a gripping disk manipulator, setting the gripping disk manipulator to be in an automatic mode, and finally turning on an operation screen switch of the electrostatic spraying machine to enter the setting of a spraying program.
Electrostatic coating machine parameters: pressing a green power button, starting a PLC operation program, turning on power illumination, setting the running track of a spray gun, and adjusting the parameters of an X.Y.Z axis by actual spraying products; starting an exhaust fan switch, setting the speed to be about 30HZ, the XY speed to be 400-; the high-voltage electrostatic powder spraying has the air pressure of 2-4KG, the atomization of 0.1-0.2 and the voltage of 50-65 KV.
And (3) spraying operation procedures: the insulating powder was placed in a fluidization bucket, the air pressure was adjusted to 0.2MPA, and vibration was turned on.
An operator places the magnetic core on a flat desktop according to a prepared die sleeve plate in advance and puts the magnetic ring in a tray; the positions are evenly arranged. The tray was returned to the oven for baking for 15 minutes.
Sampling and detecting the sprayed product: and (5) after the sprayed product is placed and cooled, testing the spraying thickness, measuring by using a film thickness meter, and recording. And the voltage resistance strength, the adhesive force, the coating appearance, the color, the electrical property and the inductance are detected and recorded one by one.
If the spraying magnetic ring needs better appearance effect, the roll coating process needs to be further implemented in fluidized bed equipment.
And (3) detection:
the product performance detection is an indispensable final process, and all the previous process links are carried out to produce products meeting the requirements of customers; generally, the differential mode inductor needs to test electrical performance parameters such as no-load inductance, direct current superposition inductance, power loss, direct current resistance, insulation resistance, turn-to-turn voltage resistance, voltage resistance and the like. These matters relate to the production process after the winding of the iron core and will not be described in detail here.
The above embodiments are merely illustrative of the present invention, and should not be construed as limiting the scope of the present invention, and all designs identical or similar to the present invention are within the scope of the present invention.
Claims (2)
1. A production process of a PFC differential mode inductance magnetic ring is characterized by comprising the following steps:
winding the strip material: processing the selected iron-based amorphous belt through an iron core automatic winding machine according to the designed size of the iron core;
iron core annealing: putting the processed and formed iron core into a vacuum furnace, heating under the protection of nitrogen, preserving heat when the heating temperature reaches 370-380 ℃, preserving heat for 40-75 minutes, and then lifting the iron core out of the vacuum furnace for cooling to finish the annealing process of the iron core;
carrying out magnetization treatment on the annealed iron core;
and (3) iron core solidification: mixing epoxy resin and a curing accelerator, pouring the mixture into a vacuum tank in a vacuum impregnator, putting the annealed iron core into the vacuum tank in the vacuum impregnator for iron core curing, and then putting the cured iron core into an oven for drying;
cutting an air gap: precisely cutting the cured iron core according to the designed air gap value;
air gap treatment: inserting an epoxy plate into the air gap of the core cut;
spraying: carrying out insulation spraying on the iron core subjected to air gap treatment;
the iron core annealing is carried out according to the following method:
sequentially penetrating the wound iron cores on the stainless steel pipe, and overlapping;
hoisting the stainless steel pipe with the iron core into a vacuum furnace, and starting a vacuum pump to vacuumize the vacuum furnace;
starting heating, and recording time and ambient temperature;
injecting nitrogen into the vacuum furnace, closing a nitrogen valve when the pressure in the vacuum furnace is increased to be 0.1Mpa greater than the standard atmospheric pressure, starting to record the temperature of the test point, and recording once every 15 minutes;
starting a magnetizing current; when the temperature of at least 50% of the iron core temperature test points reaches 370-380 ℃, carrying out heat preservation for 40-75 minutes;
after the heat preservation time is up, opening an air release valve of the annealing furnace, opening a furnace cover when the pressure in the furnace is reduced to the normal pressure state, and lifting the iron core out by a crane to cool down to complete the annealing process;
the iron core curing is carried out according to the following method:
mixing epoxy resin and a curing accelerator according to a ratio of 5:6, pouring the mixed epoxy resin and the curing accelerator into a vacuum tank of a vacuum impregnator, and fully stirring;
immersing the whole material placing tray for placing the annealed iron core into a vacuum tank to enable the whole iron core to be submerged below the liquid level;
closing the upper cover, the blow-down valve and the air release valve of the vacuum tank, opening a vacuum pump valve and a vacuum pump, pumping out air in the tank, and when the vacuum pressure gauge stops, the vacuum tank is nearly in a vacuum state;
keeping the vacuum state for 10 minutes to ensure that the iron core is fully contacted with the curing agent;
opening an air release valve after 10 minutes, opening a tank cover when the air pressure of the vacuum tank is recovered to normal pressure, and taking out the iron core to be fully drained;
if the outside air temperature is low, the curing agent adhered to the surface of the iron core is in a viscous state, and the curing agent is quickly drained by low-temperature baking;
and then, placing the tray into an oven for baking, adjusting the heating speed of the oven to heat to 393K at 3K/min during baking, preserving the heat for 360min, and taking out the iron core.
2. The process for producing a PFC differential mode inductance magnetic ring as claimed in claim 1, further comprising detecting the sprayed iron core, wherein the detecting comprises detecting electrical properties of no-load inductance, DC superimposed inductance, power loss, DC resistance, insulation resistance, turn-to-turn withstand voltage and withstand voltage of the iron core.
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| CN113030191B (en) * | 2021-02-26 | 2023-03-17 | 浙江大学 | Resin curing degree in-situ monitoring method based on embedded fiber sensor |
| CN113257560A (en) * | 2021-04-16 | 2021-08-13 | 青县择明朗熙电子器件有限公司 | Manufacturing process of rectangular nanocrystalline spraying magnetic core suitable for medium-high frequency environment |
| CN114360886B (en) * | 2022-01-14 | 2023-10-17 | 沈阳工业大学 | Amorphous and silicon steel universal curve cutting device and control method |
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