Multi-electromagnet parallel soft-landing electromagnetic actuator

Abstract

A kind of multi-electromagnet parallel soft landing electromagnetic actuator belongs to the field of reciprocating compressor. The existing electromagnetic drive reciprocating compressor gas regulation system has large landing noise, high sensitivity and poor controllability, and cannot be fine production control. This paper proposes a new type of multi-electromagnet parallel soft landing electromagnetic actuator, which reduces inductance by parallel connection of multiple winding coils, improves the control characteristics of electromagnetic actuators, and designs a V-shaped groove buffer device to effectively reduce the landing speed of electromagnetic actuators. Through reasonable design of the structure and size of the electromagnet, it is ensured that the electromagnet can generate enough electromagnetic force to push the load, realize soft landing of the electromagnetic actuator, and the control characteristics are optimized to realize fine control, meeting the stepless gas regulation demand of reciprocating compressor.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of reciprocating compressor gas regulation, and relates to a novel multi-electromagnet parallel soft-landing electromagnetic actuator for stepless gas regulation by an electromagnetic drive air valve. BACKGROUND

[0002] Most of the stepless gas regulation systems in China at present are hydraulic actuator that opens the air valve, and the hydraulic actuator has many oil lines, high cost, inconvenient maintenance, and the oil is flammable and explosive, which may cause pollution to the compressed medium.

[0003] Patent CN115992744A proposes an electromagnetic actuator with a gasket made of non-magnetic material added at the limit position of the electromagnet for buffering and noise reduction, which does not reduce the movement speed at the end of the armature movement and belongs to hard landing noise reduction; the electromagnetic valve used in patent CN207609641U serves a hydraulic gas regulation system and is not a true electromagnetic gas regulation system; patent CN113958485A proposes an electromagnetic actuator for reciprocating compressor gas regulation, which only designs the structure of the electromagnetic actuator to obtain the electromagnetic force and temperature rise characteristics to meet the performance requirements of the reciprocating compressor and does not solve the noise problem and control characteristics problem of the electromagnetic actuator under actual working conditions.

[0004] The application proposes a novel multi-electromagnet parallel soft-landing electromagnetic actuator for stepless gas regulation by an electromagnetic drive unloader opening the inlet valve, which realizes soft landing, reduces working noise, reduces the inductance of the electromagnetic actuator, and improves the control characteristics, and can meet the requirements of reciprocating compressor gas regulation under different working conditions. SUMMARY

[0005] The application aims to solve the technical problem of designing an electromagnetic actuator for reciprocating compressor gas regulation.

[0006] The application solves the above technical problems by the following technical solutions:

[0007] A multi-electromagnet parallel soft-landing electromagnetic actuator, characterized in that:

[0008] The direct current electromagnetic actuator comprises an upper end cover, an electromagnetic actuator shell, a base, an armature, a V-shaped groove buffer device and parallel wound magnetic coils.

[0009] During initial installation, the coil framework is first installed on the inner surface of the pole shoe and the winding coil is installed, and then the electromagnetic actuator shell body is fixed to the pole shoe, the shell is fixed to the pole shoe through six transverse countersunk head bolts, and the countersunk head bolts are symmetrically arranged with the unloader top rod central shaft as the symmetry axis; secondly, the lower sleeve is installed on the unloader top rod, and the upper guide rail, the lower guide rail, the V-shaped groove assembly and the upper sleeve are assembled and installed on the armature to jointly form the moving part of the electromagnetic actuator; then the upper limiting ring is connected to the end cover through a screw, the electromagnetic actuator moving part is installed into the electromagnetic actuator moving working cavity, and the assembled end cover part and the electromagnetic actuator shell body are connected through a screw with an O-ring in between; the stroke displacement of the electromagnet top rod is adjusted by adjusting the thickness of the upper limiting ring and the lower limiting gasket; at the same time, a sensor hole is left on the upper end of the electromagnet, and the displacement of the armature and the unloader top rod is observed by installing an eddy current sensor;

[0010] The electromagnetic actuator is controlled by a single-chip microcomputer, the controller generates positive and negative excitation voltages to charge and discharge the electromagnet, the electromagnetic actuator winding coil generates an electromagnetic force when charged, the armature moves downward under the drive of the electromagnetic force until it contacts the lower limiting gasket; the unloader top rod moves downward to open the valve piece under the electromagnetic force transmitted by the armature, so that the excess gas of the compressor flows back; when the remaining gas in the working cavity reaches the required gas volume for production, the electromagnetic actuator is discharged, the electromagnetic force disappears, and the spring in the unloader pushes the unloader top rod and the armature to reset and withdraw, and the inlet valve is closed.

[0011] The controller generates positive and negative voltages at different times, which act on the electromagnet to meet the inductance and control characteristics of the electromagnet, and the V-shaped groove buffer device acts on the electromagnetic actuator to meet the soft landing characteristics of the electromagnetic actuator.

[0012] The electromagnetic actuator armature movement and V-shaped groove buffer device working mode are characterized by the following steps:

[0013] 1) At the initial moment, the electromagnetic actuator is not powered on, under the action of the cylinder pressure, the reset spring and the V-shaped groove buffer device, the upper surface of the armature contacts the upper limiting ring, and the armature is located at the x L mm stroke position, at this time the unloader valve piece is not opened, and the gas volume is not adjusted;

[0014] 2) When the electromagnetic actuator is energized and the armature moves, a positive charge is applied to the parallel winding coil during the ejection process. Under the action of the magnetic field generated by the parallel winding coil, the electromagnet begins to move downward, causing the unloader pressure fork to push open the valve plate, and the gas is discharged from the unloader to achieve gas volume regulation. L -x2mm stroke, the armature is at the upper limit position, and the V-groove buffer device applies a positive force to the armature. When the armature is in the x2-x1mm stroke, the armature is in the middle position, and the V-groove buffer device does not apply a force to the armature. When the armature is in the x1mm-0mm stroke, the armature is in the lower limit position, and the V-groove buffer device applies a reverse force to the armature, causing the armature speed to decrease rapidly, achieving a soft landing.

[0015] 3) During the retraction process, the electromagnetic actuator is energized and counter-current is applied to the parallel winding coil, generating a magnetic field in the parallel winding coil. Under the action of the pressure in the cylinder, the return spring, and the V-groove buffer device, the armature is retracted. When the stroke is 0-x1mm, the armature is at the lower limit position, and the V-groove buffer device applies a positive force to the armature. When the stroke is x1-x2mm, the armature is in the middle position, and the V-groove buffer device does not apply a force to the armature. L When the stroke reaches mm, the armature is at the upper limit position, and the V-groove buffer device applies a reverse force to the armature to achieve a soft landing;

[0016] 4) Repeat 2)-3).

[0017] The specific calculation method for determining the structural parameters of the V-groove buffer device is as follows:

[0018] 1). Determination of inner and outer diameters of V-groove buffer devices:

[0019] I. Electromagnetic force F C Determination

[0020] like Figure 3 As shown in the figure, the electromagnetic actuator is subjected to the following forces during its motion process:

[0021] Ejection process:

[0022] When x2mm≤x<x L mm,

[0023]

[0024] When x1mm≤x<x2mm,

[0025]

[0026] When 0mm≤x<x1mm,

[0027]

[0028] Ejection holding process:

[0029] F c +mg=F T +F V +F p +F 支 (x=x l mm)

[0030] Withdrawal process:

[0031] When 0 mm≤x

[0032]

[0033] When x1mm≤x

[0034]

[0035] When x2mm≤x L mm,

[0036]

[0037] In the above formulas:

[0038] F C : electromagnetic force;

[0039] m: mass of moving part;

[0040] g: acceleration of gravity;

[0041] F T : unloader reset spring force, F T =k(x+l);

[0042] F 支 : unloader limit disc support force;

[0043] k: stiffness coefficient of spring;

[0044] x: unloader displacement;

[0045] l: spring pre-compression amount;

[0046] f: system friction force;

[0047] x L : maximum travel of armature;

[0048] t: unloader ejection process time;

[0049] F P : gas force in cylinder;

[0050] F V: V-groove buffer device force;

[0051] The electromagnetic force F generated by the electromagnet c Need to meet:

[0052] F c +mg-F T -F V -F p ≥0

[0053] Combining the above equations to determine the electromagnetic force F c The design range is selected as the critical electromagnetic force F c The design electromagnetic force F is rounded to 1.5 times the value d ,Right now:

[0054] F d =round(1.5xF c )

[0055] Ⅱ. Determine the armature diameter d by the electromagnetic attraction formula x The electromagnetic attraction formula is as follows:

[0056]

[0057] In the above formula:

[0058] B δ : magnetic induction intensity;

[0059] III. V-groove buffer device outer diameter D and armature diameter d x Equal, from III we can know:

[0060] D=d x

[0061] The relationship between the boss on the armature and the V-groove buffer device is equivalent to the relationship between the key and the keyway. Check the national standard "GB / T1095-79; Standard dimensions of flat keys and keyways" to determine the inner diameter d of the V-groove buffer device, the boss width b1, the boss height t1, the V-groove width b2, and the V-groove depth t2.

[0062] IV. Assume that the V-groove buffer device height is L1, the V-groove buffer assembly height is L2, the upper and lower guide rails height is L3, the main working surface width is L4, the armature boss length is L5, and the V-groove working side length is L6.

[0063] L1=0.5h=L2+2L3

[0064] L3=0.1L1

[0065]

[0066] L2=2L4+(b2-y)tanθ+L6

[0067]

[0068] In the above formula:

[0069] R e is the yield strength of the material;

[0070] h: winding coil height, winding coil height h is only related to coil thickness b, according to the following formula, the size of the coil height h is determined, that is:

[0071] h = 2.45 x b

[0072] The coil thickness b is determined by the inner diameter D of the shell n , the armature diameter d x , and the coil skeleton and insulation thickness , which is calculated as shown in the following table:

[0073] D n = 2.65 x d x

[0074]

[0075] Where the coil thickness b and the coil skeleton and insulation thickness satisfy the following relationship:

[0076]

[0077] The above two formulas are solved to determine the size of the coil thickness b, and the winding coil height h is obtained;

[0078] θ: V-shaped groove angle

[0079] y: V-shaped groove buffer assembly main working face width

[0080] Determination of V-shaped groove angle θ

[0081] The structure can be obtained,

[0082]

[0083] The V-shaped groove buffer device must ensure that the armature x l mm displacement

[0084]

[0085] The number N of parallel winding coils of the electromagnet is confirmed, and the specific calculation is as follows:

[0086] 1) This paper adopts N parallel winding coil method to reduce inductance and improve the control characteristics of electromagnetic actuator, including the inductance L' after parallel connection 并The change of the total load current I of the electromagnetic actuator 总 The calculation method is as follows:

[0087] I. Determination of the inductance of the coil:

[0088] When the current passes through the coil, a magnetic field is formed in the coil, and the induced magnetic field will generate an induced current to resist the current passing through the coil. It is a circuit parameter that describes the effect of inducing electromotive force in the coil or in another coil due to the change of the current in the coil, and the specific calculation formula is as follows:

[0089]

[0090] In the above formula:

[0091] μ0: magnetic permeability;

[0092] N: number of turns of the coil;

[0093] A: effective cross-sectional area;

[0094] Q: average magnetic path length;

[0095] II. Determination of the total inductance of the parallel coil:

[0096] According to the parallel inductance change formula, the inductance of a single coil and the total inductance can be obtained, and the calculation formula is as follows:

[0097] If there is no coupling relationship between n inductors, then according to the parallel relationship and Kirchhoff's current node theorem, the total inductance L' of n parallel coils can be obtained as follows: 并

[0098]

[0099] According to the Lenz law, the inductive reactance X L

[0100] X L′ = ωL' = 2πfL'

[0101] In the above formula:

[0102] ω: represents the angular frequency of the applied current, with the unit of rad / s (radian per second);

[0103] f: represents the frequency of the applied current, with the unit of Hz (hertz);

[0104] L': represents the self-inductance coefficient; the unit is H (henry)

[0105] X L′ : inductive reactance of the coil, with the unit of Ω (ohm)

[0106] The total current and total inductive reactance in the circuit are as follows:​​

[0107] X L′并 = ωL = 2πfL' 并

[0108]

[0109] In the above formula:

[0110] U: represents the total voltage in the line, unit is volt (V);

[0111] III. Determination of the number of parallel coils N:

[0112] N winding coils in parallel to meet the coil temperature rise in the allowable range, as follows:

[0113] According to the actual working conditions required, check the national standard "GB / T 11026.1-2016 Electrical Insulating Materials Heat Resistance" to get the coil insulation grade, according to the highest allowable temperature table of each level of insulation material, determine the highest allowable temperature and temperature rise range of the coil, check the coil heat dissipation coefficient K T , using Newton formula to calculate:

[0114]

[0115] In the above formula:

[0116] ΔT: the stable temperature rise of the coil after long-term energization;

[0117] K T : heat dissipation coefficient;

[0118] S: coil heat dissipation area;

[0119] I 总 : the actual current in the electromagnet working;

[0120] The expression of the coil heat dissipation area S is as follows:

[0121] S = S n + 2.4S w

[0122] In the above formula:

[0123] S n : the inner surface area of the coil;

[0124] S w : the outer surface area of the coil;

[0125] S n , S w Through the armature diameter d x , the thickness of the coil framework and insulation The thickness of the coil b and the height of the coil h are determined:

[0126]

[0127] Characteristic check

[0128] I. Size characteristic of electromagnetic force:

[0129] After determining the structural parameters of the electromagnetic actuator, modeling and simulation are carried out by using simulation software to determine whether the electromagnetic force meets the requirements, i.e. greater than or equal to the design electromagnetic force F d ;

[0130] II. Soft landing characteristic of V-shaped groove buffer device of electromagnetic actuator:

[0131] By using simulation software, it is determined whether the landing speed of the new multi-electromagnetic-iron parallel soft-landing electromagnetic actuator at the end of the ejection process and the end of the withdrawal process is improved.

[0132] III. Control characteristic of electromagnetic actuator:

[0133] By using simulation software for modeling and simulation, it is determined whether the inductance of the new multi-electromagnetic-iron parallel soft-landing electromagnetic actuator is consistent with the calculation result, whether the inductance characteristic is improved, and whether the transient characteristic of the new multi-electromagnetic-iron parallel soft-landing electromagnetic actuator is optimized compared with the single-electromagnetic-iron electromagnetic actuator, i.e. stable working condition appears in the first period.

[0134] By using simulation software, the forward and reverse driving voltages are designed to determine whether the control characteristic of the new multi-electromagnetic-iron parallel soft-landing electromagnetic actuator is improved, i.e. whether the control sensitivity is improved and whether the adjustable interval is improved. BRIEF DESCRIPTION OF DRAWINGS

[0135] Figure 1 It is a structural schematic diagram of the electromagnetic actuator;

[0136] Figure 2 It is a whole schematic diagram of the new multi-electromagnetic-iron parallel soft-landing electromagnetic actuator;

[0137] Figure 3 It is a force analysis diagram of the unloader air valve;

[0138] Figure 4 It is a structural parameter schematic diagram of the winding coil of the electromagnetic actuator;

[0139] Figure 5 It is a structural parameter schematic diagram of the V-shaped groove assembly;

[0140] Figure 6 It is a working principle diagram of the V-shaped groove buffer device;

[0141] Figure 7 It is a driving voltage waveform diagram generated by the controller;

[0142] Figure 8 For Figure 7 Transient electromagnetic force under the drive voltage waveform graph and the design electromagnetic force comparison graph;

[0143] Figure 9 For new type of multi-electromagnet parallel soft landing electromagnetic actuator inductance size comparison chart;

[0144] Figure 10 For in Figure 7 Displacement waveform comparison chart obtained under the drive voltage waveform graph;

[0145] Figure 11 For single electromagnet electromagnetic actuator control characteristic chart;

[0146] Figure 12 For new type of multi-electromagnet parallel soft landing electromagnetic actuator control characteristic chart;

[0147] Figure 13 For armature movement speed comparison chart;

[0148] BRIEF DESCRIPTION OF DRAWINGS:

[0149] 1-end cover;

[0150] 2-O ring;

[0151] 3-magnetic actuator shell;

[0152] 4-V-shaped groove upper guide rail;

[0153] 5-winding coil;

[0154] 6-V-shaped groove lower guide rail;

[0155] 7-gasket;

[0156] 8-coil clamp;

[0157] 9-pole shoe;

[0158] 10-unloading device top rod;

[0159] 11-lower sleeve;

[0160] 12-pressing barrel;

[0161] 13-spring;

[0162] 14-nut;

[0163] 15-buffer box;

[0164] 16-isolation sleeve;

[0165] 17-lift limiter;

[0166] 18 valve plates;

[0167] 19-press fork;

[0168] 20-spacer pad;

[0169] 21- screw;

[0170] 22-countersunk bolts;

[0171] 23-lower limit gasket;

[0172] 24-V-groove assembly;

[0173] 25-armature;

[0174] 26-upper sleeve;

[0175] 27-screw;

[0176] 28-screws;

[0177] 29-sensor hole;

[0178] 30-Upper limit ring

[0179] 31- electromagnetic actuator;

[0180] 32-Unloader

[0181] 33-Air valve

[0182] 34-Controller DETAILED DESCRIPTION

[0183] The method of the present invention is further described below with reference to the accompanying drawings and implementation examples:

[0184] 1. Such as Figure 1 As shown in FIG, a new type of multi-electromagnet parallel soft landing electromagnetic actuator for stepless air volume regulation of electromagnetic driven reciprocating compressor is shown in FIG. Figure 2As shown, including electromagnetic actuator 31, unloader 32, gas valve 33, controller 34, initial installation, first coil clamp 8 is installed on the inner surface of the pole shoe 9 and the winding coil 5 is installed, and then the electromagnetic actuator outer shell 3 is fixed to the pole shoe 9, the outer shell is fixed to the pole shoe 9 by six transverse countersunk head bolts 22, and the countersunk head bolts 22 are symmetrically arranged with the unloader top rod 10 center axis as the symmetry axis; secondly, the lower sleeve 11 is installed on the unloader top rod 10, and then the upper guide rail 4, the lower guide rail 6, the V-shaped groove assembly 24 are assembled and the upper sleeve 26 is installed on the armature 25, the armature 25 is connected with the unloader top rod 10 through threads, and the unloader top rod 10 and the armature 25 together constitute the moving parts of the electromagnetic actuator; then the upper limit ring 30 is connected with the end cover 1 through the screw 28, the electromagnetic actuator moving part is installed into the electromagnetic actuator moving working cavity, the assembled end cover part is connected with the electromagnetic actuator outer shell 3 through the screw 27, and the O-ring 2 is added in the middle; by adjusting the thickness of the upper limit ring 30 and the lower limit gasket 23, the stroke displacement adjustment of the electromagnetic top rod 10 is realized; at the same time, the electromagnetic top rod 10 is provided with a sensor hole 29 at the upper end, and the displacement of the armature 25 and the unloader top rod 10 is observed by installing an eddy current sensor;

[0185] The electromagnetic actuator is controlled by a single-chip microcomputer, the controller 34 generates positive and negative excitation voltages to charge and discharge the electromagnet, the winding coil 5 of the electromagnetic actuator generates electromagnetic force when charged, and the armature 25 moves downward under the drive of the electromagnetic force until it contacts the lower limit gasket 23; the unloader top rod 10 is driven by the electromagnetic force transmitted by the armature 25, thereby moving downward to open the valve plate 18, so that the excess gas of the compressor flows back; when the remaining gas in the working cavity reaches the required gas volume for production, the electromagnetic actuator 31 is discharged, the electromagnetic force disappears, and the spring 13 in the unloader 32 pushes the unloader top rod 10 and the armature 25 to reset and withdraw, and the inlet valve is closed.

[0186] 2. The electromagnetic actuator is characterized in that the controller generates positive and negative voltages of different times, which act on the electromagnet to meet the inductance and control characteristics of the electromagnet. This embodiment adopts two completely same winding coils in parallel, and the specific system working condition is given as follows:

[0187]

[0188] (1) Calculate the electromagnetic force of the electromagnet and the diameter of the armature according to the system parameters:

[0189] Ⅰ. The maximum spring load force required by the electromagnet 1:

[0190] F T = k (x + l) = 40000 * 0.0075 = 300N

[0191] Conditions that the electromagnetic force needs to meet:

[0192] F c +70-300-200-200≥0

[0193] Simultaneous equations above can determine the design range of electromagnetic force F c 630N, to ensure that the electromagnetic actuator 31 can be unloaded under the load of the top rod 10 quickly, and can adapt to a variety of conditions, the design of electromagnetic force value should leave a certain margin, here select the critical electromagnetic force F c 1.5 times the value of the whole as the design electromagnetic force F d , that is:

[0194] F d = round (1.5 x F c ) = 1000N

[0195] II. From the displacement x = 3mm, the design electromagnetic force F d = 1000N, to determine the electromagnetic force 1 and the structure factor size:

[0196]

[0197] II. According to the structure factor K = 33, select the working air gap magnetic induction intensity curve in the "electromagnetic structure factor and type relationship table", determine the magnetic induction intensity B δ ≈10500G S , the size of the magnetic induction intensity B δ is also related to the armature material, the armature material is DT4 series material in the embodiment, according to the national standard "GB / T6983-2008: electromagnetic pure iron", the magnetic induction intensity of DT4 series material is between 1.2 ~ 1.8T, the B δ =12000G S ;

[0198] III. The size of the armature diameter is determined by the electromagnetic force formula:

[0199]

[0200] (2) calculate the V type groove buffer device parameters:

[0201] I. V type groove buffer device outer diameter D and armature diameter d x are equal, from III:

[0202] D = d x = 48mm

[0203] II. The relationship between the upper boss of the armature and the V-shaped groove buffer device is equivalent to the relationship between the key and the keyway. According to the national standard GB / T1095-79, the standard size of the key and the keyway, the width of the boss b1 is determined to be 14 mm, the height of the boss t1 is determined to be 3.5 mm≈4 mm, the width of the V-shaped groove b2 is determined to be 14 mm, and the depth of the V-shaped groove t2 is determined to be 3.8 mm≈4 mm. The inner diameter d of the V-shaped groove buffer device is D-t2=44 mm.

[0204] III. The height L1 of the V-shaped groove buffer device, the height L2 of the V-shaped groove buffer assembly, the height L3 of the upper and lower guide rails, the width L4 of the main working surface, the length L5 of the boss of the armature, and the length L6 of the working side surface of the V-shaped groove are determined.

[0205] The height h of the winding coil is only related to the thickness b of the coil. According to the following formula, the size of the coil height h is determined, that is:

[0206] h=2.45×b

[0207] The thickness b of the coil is determined by the inner diameter D of the shell n , the diameter d of the armature x , and the thickness of the coil skeleton and insulation , and the calculation table is as follows:

[0208] D n =2.65×d x

[0209]

[0210] Wherein the thickness b of the coil and the thickness of the coil skeleton and insulation satisfy the following relationship:

[0211]

[0212] By solving the above two equations, we get

[0213] b=34 mm

[0214] Thus, the total height of the winding coil is obtained:

[0215] h=2.45×34≈84 mm

[0216] The height of a single coil is:

[0217] h1=42 mm

[0218] L1=0.5h=L2+2L3=42 mm

[0219] Let L3=0.1L1≈4 mm, then L2=34 mm

[0220]

[0221] The yield strength of soft iron 1010 is R e =205Mpa, calculated as follows:

[0222]

[0223] 1mm≤L4≤4mm

[0224] Depend on Figure 5 The structure can obtain the angle range of the working surface of the V-groove buffer component. In this embodiment, L4=1mm and the working gap width y of the V-groove buffer component=2mm are selected, and the following can be obtained:

[0225]

[0226] The V-groove buffer device must ensure that the armature x l mm displacement

[0227]

[0228] Available

[0229] 45°≤θ<63.5°

[0230] In this embodiment, θ=45° is selected;

[0231] L6=L2-2L4-(b2-y)tanθ=25mm

[0232]

[0233] 6. The electromagnetic actuator is characterized in that the number N of parallel winding coils of the electromagnet is determined by the following calculation:

[0234] 1) This paper adopts the method of connecting N winding coils in parallel to reduce the inductance and improve the control characteristics of the electromagnetic actuator, including the inductance L′ after parallel connection. 并 The change of the total current carrying capacity of the electromagnetic actuator I 总 , the calculation method is as follows:

[0235] Ⅰ. Determination of single coil inductance:

[0236] When current passes through a coil, a magnetic field is induced in the coil, which in turn generates an induced current to resist the current passing through the coil. It is a circuit parameter that describes the induced electromotive force effect caused in the coil or in another coil due to the change of coil current. The specific calculation formula is as follows:

[0237]

[0238] II. Determination of the total inductance of parallel coils:

[0239] According to the parallel inductance change formula, the size of single coil inductance and total inductance can be obtained, and the calculation formula is as follows:

[0240] There is no coupling relationship between n inductors, so according to the parallel relationship and Kirchhoff's current node theorem, the total inductance L' of n coils in parallel can be obtained 并 As follows:

[0241]

[0242] According to the law of Lenz, the inductive reactance

[0243]

[0244] III. Determination of the number N of coil parallel:

[0245] N winding coils in parallel need to meet the coil temperature rise within the allowable range, which is calculated as follows:

[0246] According to the actual working condition requirement, check the national standard "GB / T 11026.1-2016 Electrical Insulating Materials Heat Resistance", select the coil insulation grade as A level in this embodiment, check the highest allowable temperature table of each level of insulation material, determine that the highest allowable temperature of the coil should be less than 105℃, and the temperature rise should be less than 60℃, check the coil heat dissipation coefficient K T , using Newton formula to calculate:

[0247]

[0248] The expression of coil heat dissipation area S is as follows:

[0249] The inner surface area S of the coil n , the outer surface area S of the coil w Through the armature diameter d x , the coil framework and insulation thickness The coil thickness b and coil height h are determined:

[0250]

[0251] S=S n +2.4S w =0.099m 2

[0252]

[0253] In this embodiment, n=2 is selected, and the total inductance L' of parallel coils is 并 :

[0254]

[0255] 7. Characteristic check

[0256] I. Size characteristic of electromagnetic force:

[0257] After determining the structural parameters of the electromagnetic actuator, modeling and simulation calculation are performed using simulation software to determine the electromagnetic force size of 1565.79 N, which is greater than the required electromagnetic force, thus meeting the design requirements. Figure 8

[0258] II. Soft landing characteristic of V-shaped groove buffer device of electromagnetic actuator:

[0259] Using simulation software, the speed of the new multi-electromagnet parallel soft landing electromagnetic actuator at the end of the ejection process is 358.6 mm / s, and the speed of the single electromagnet electromagnetic actuator at the end of the ejection process is 427.9 mm / s, which is reduced by 69.3 mm / s; the landing speed of the new multi-electromagnet parallel soft landing electromagnetic actuator at the end of the withdrawal process is 467.6 mm / s, and the landing speed of the single electromagnet electromagnetic actuator at the end of the withdrawal process is 539.6 mm / s, which is reduced by 72 mm / s, as shown in Figure 9

[0260] III. Control characteristic of electromagnetic actuator:

[0261] Modeling and simulation are performed using simulation software to determine the inductance of the new multi-electromagnet parallel soft landing electromagnetic actuator, which is 10.6 H, consistent with the calculated result of 10.5 H, and the inductance of the single electromagnet electromagnetic actuator is 44.6 H, the inductance characteristic is improved, as shown in Figure 10

[0262] As shown in Figure 11 , the single electromagnet electromagnetic actuator is stable at the sixth cycle, the new multi-electromagnet parallel soft landing electromagnetic actuator is stable at the second cycle, and the new multi-electromagnet parallel soft landing electromagnetic actuator enters the stable working condition four cycles earlier, and the transient characteristic is good.

[0263] Using simulation software, the forward and reverse drive voltages are designed, the control characteristic of the single electromagnet electromagnetic actuator is to change the positive time by 1 ms, and the ejection holding time is adjusted by 19.5 ms; the control characteristic of the new multi-electromagnet parallel soft landing electromagnetic actuator is to change the positive time by 1 ms, and the ejection holding time is adjusted by 1.3 ms; the adjustable range of the positive time of the single electromagnet electromagnetic actuator is 141 ms-145 ms, and the adjustable range of the positive time of the new multi-electromagnet parallel soft landing electromagnetic actuator is 115 ms-145 ms. It is determined that the control characteristic of the new multi-electromagnet parallel soft landing electromagnetic actuator is obviously improved compared with the single electromagnet electromagnetic actuator, the control sensitivity is reduced by 95%, and the adjustable interval is increased by 25 ms, as shown in Figure 12 , Figure 13 .​​​

[0264] Conclusions:

[0265] A new type of multi-electromagnet parallel soft landing electromagnetic actuator applied to stepless gas volume regulation of reciprocating compressor is designed in this paper. Through reasonable design of structure parameters of V-shaped groove buffer device and number of parallel winding coils, the performance optimization effect is verified by software simulation.

[0266] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, not for limiting the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all changes made by those skilled in the art without departing from the spirit and technical idea of the present application shall be covered by the claims of the present application.

Claims

1. A multi-electromagnet parallel soft landing electromagnetic actuator, characterized by: It includes a DC electromagnetic actuator, an air valve and an unloader. The DC electromagnetic actuator consists of an upper end cover, an electromagnetic actuator housing, a base, an armature, a V-groove buffer device, and a parallel magnetic coil. The main structure of the electromagnetic actuator adopts a plane column baffle center tube type electromagnetic actuator. During the initial installation, first install the coil skeleton on the inner surface of the pole shoe and install the winding coil, then fix the electromagnetic actuator housing to the pole shoe, and the housing is fixed to the pole shoe by six horizontal countersunk bolts, and the countersunk bolts are symmetrically arranged with the center axis of the unloader push rod as the symmetry axis; secondly, install the lower sleeve on the unloader push rod, and then assemble the upper guide rail, lower guide rail, and V-groove assembly and install the upper sleeve on the armature, which together constitute the moving part of the electromagnetic actuator; then connect the upper limit ring to the end cover by screws, install the electromagnetic actuator moving part into the electromagnetic actuator moving working chamber, and then connect the assembled end cover component to the electromagnetic actuator housing by screws, and install an O-ring in the middle; by adjusting the thickness of the upper limit ring and the lower limit gasket, the stroke displacement of the electromagnet push rod can be adjusted; at the same time, a sensor hole is left at the upper end of the electromagnet, and the displacement of the armature and the unloader push rod is observed by installing an eddy current sensor; The electromagnetic actuator is controlled by a single-chip microcomputer, and the controller generates positive and negative excitation voltages to charge and discharge the electromagnet. When the winding coil of the electromagnetic actuator is charged, an electromagnetic force is generated, and the armature moves downward under the drive of the electromagnetic force until it contacts the lower limit gasket; the unloader push rod is subjected to the electromagnetic force transmitted by the armature, so that it moves downward to push the valve plate open, allowing excess gas in the compressor to flow back; when the remaining gas in the working chamber reaches the gas volume required for production, the electromagnetic actuator is discharged, the electromagnetic force disappears, and the spring in the unloader pushes the unloader push rod and armature to reset and withdraw, and the intake valve is closed.

2. The electromagnetic actuator according to claim 1, characterized in that: The controller generates positive and negative voltages at different times, which act on the electromagnet to meet the inductance and control characteristics of the electromagnet. The V-groove buffer device acts on the electromagnetic actuator to meet the soft landing characteristics of the electromagnetic actuator.

3. The armature movement and V-groove buffer device working mode of the electromagnetic actuator according to claim 1 are characterized in that Here are the steps: 1) Initially, the electromagnetic actuator is not energized. Under the action of the cylinder pressure, the return spring, and the V-groove buffer device, the upper surface of the armature contacts the upper limit ring, and the armature is at x L mm stroke position, at this time the unloader valve is not pushed open and the gas volume is not adjusted; 2) When the electromagnetic actuator is energized and the armature moves, a positive charge is applied to the parallel winding coil during the ejection process. Under the action of the magnetic field generated by the parallel winding coil, the electromagnet begins to move downward, causing the unloader pressure fork to push open the valve plate, and the gas is discharged from the unloader to achieve gas volume regulation. L -x2mm stroke, the armature is at the upper limit position, and the V-groove buffer device applies a positive force to the armature. When the armature is in the x2-x1mm stroke, the armature is in the middle position, and the V-groove buffer device does not apply a force to the armature. When the armature is in the x1mm-0mm stroke, the armature is in the lower limit position, and the V-groove buffer device applies a reverse force to the armature, causing the armature speed to decrease rapidly, achieving a soft landing. 3) During the retraction process, the electromagnetic actuator is energized and counter-current is applied to the parallel winding coil, generating a magnetic field in the parallel winding coil. Under the action of the pressure in the cylinder, the return spring, and the V-groove buffer device, the armature is retracted. When the stroke is 0-x1mm, the armature is at the lower limit position, and the V-groove buffer device applies a positive force to the armature. When the stroke is x1-x2mm, the armature is in the middle position, and the V-groove buffer device does not apply a force to the armature. L When the stroke reaches mm, the armature is at the upper limit position, and the V-groove buffer device applies a reverse force to the armature to achieve a soft landing; 4) Repeat 2)-3).

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