Calculation method for air gap change of single-rope winding type permanent magnet outer rotor elevator under variable load effect

Abstract

The invention provides a method for calculating the air gap change of a single-rope winding type permanent magnet outer rotor elevator under a variable load effect. The method comprises the following steps: establishing a rotor roller mechanical model of the single-rope winding type permanent magnet outer rotor elevator under variable-speed and variable-load conditions; the resultant force borne by the roller is solved when the common influence of the external steel wire rope positive pressure and the internal radial electromagnetic force is considered; calculating the air gap change induced by the radial deformation of the rotor roller in the winding process of the steel wire rope; establishing a stator core mechanical model, and calculating the air gap change induced by the radial deformation of the stator; calculating an air gap comprehensive variable quantity caused by the common bearing load of the rotor roller and the stator iron core; according to the method, the real-time air gap comprehensive variable quantity of different types of single-rope winding type permanent magnet outer rotor hoists in the variable-speed working condition operation process can be accurately and rapidly calculated according to parameters such as the load size, the diameter and the width of a roller, the number of permanent magnet poles and the number of stator grooves.

Description

Technical Field

[0001] The invention relates to a method for calculating air gap variation of a single-rope winding type permanent magnet outer rotor hoist under variable load, and belongs to the technical field of air gap variation calculation. Background Art

[0002] Permanent magnet outer rotor hoist is a kind of hoisting device that can be widely used in coal mines, metal mines, non-metallic mines to lift materials or personnel, etc. It is mainly suitable for lifting ground vertical shafts, inclined shafts and underground auxiliary transportation. During the rotation process, the drum is subjected to the normal component of the dynamic tension of the wire rope at the same time. The magnetic field force generated by the permanent magnet magnetic field and the stator winding magnetic field inside causes the air gap to change.

[0003] The invention patent of "Permanent Magnetic Outer Rotor Hoist" with application number CN201911348950.2 discloses an integrated structure, in which the stator core of the permanent magnet synchronous motor and the main shaft of the hoist are assembled through a flange structure, and the permanent magnet is bonded to the inner wall of the drum and fixed with axial and circumferential non-magnetic fixing blocks. However, the application does not disclose the specific force mode of the rotor system and stator system of the permanent magnet outer rotor hoist, nor does it involve the calculation of the air gap change caused by the dynamic load on the stator and rotor.

[0004] Regarding the calculation of air gap variation, Li Yi used the center of mass equivalent ring method to calculate the mechanical stress and strain of the hub motor rotor, and used the experimental measurement method to obtain the deviation of the stator inner circle size approximating the elliptical deformation [see Li Yi. Research on air gap deformation and vibration characteristics of built-in permanent magnet synchronous hub motor [D]. Harbin Institute of Technology, 2018.]. However, the above method is only applicable to built-in permanent magnet synchronous motors, and cannot provide theoretical guidance for the calculation of rotor stress and strain of surface-mounted external rotor permanent magnet synchronous motors. At the same time, the experimental measurement method is applicable to the inner circle size deviation of the stator of small and medium-sized built-in permanent magnet synchronous motors, and cannot achieve the measurement of the outer circle size of the stator of large permanent magnet external rotor hoists.

[0005] Wen.S et al. established a stress analysis model for high-speed flywheel rotors based on thick-walled cylinder theory and used the microelement method to calculate the maximum radial stress of the rotor under centrifugal force [see Wen S. Analysis of maximum radial stress location of composite energy storage flywheel rotor [J]. Archive of Applied Mechanics, 2014, 84: 1007-1013.]. Daniel Smith used the finite element method to analyze a 100kW outer rotor permanent magnet synchronous motor under 30,000 r / min operating conditions. The position where the rotor contacts its sleeve had cracks that gradually extended from the outside to the inside, and the centrifugal force was the main factor causing this failure [see Smith DJB, Mecrow BC, Atkinson GJ, et al. Shear stress concentrations in permanent magnet rotor sleeves [C] / / The XIX International Conference on Electrical Machines-ICEM 2010. IEEE, 2010: 1-6.]. However, the above method is suitable for calculating the radial stress and strain of the rotor of a high-speed permanent magnet synchronous motor under the action of centrifugal force, but is not suitable for a low-speed, high-torque permanent magnet synchronous motor. Summary of the invention

[0006] The purpose of the present invention is to provide a method for calculating the air gap change of a single-rope wound permanent magnet outer rotor hoist under variable load to solve the problem of how to calculate the air gap change of a single-rope wound permanent magnet outer rotor hoist in the prior art.

[0007] The technical solution of the present invention is:

[0008] A method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load, comprising the following steps:

[0009] S1. Establish the mechanical model of the rotor drum of a single-rope-wound permanent magnet outer rotor hoist under variable speed and variable load conditions;

[0010] S2. Calculate the positive pressure of the external wire rope, including the positive pressure generated by the wire rope tension on the drum surface under two working conditions: single-layer single-turn winding and single-layer full-turn winding, and calculate the internal radial electromagnetic force, and solve the resultant force on the drum when considering the combined influence of the external wire rope positive pressure and the internal radial electromagnetic force;

[0011] S3. Calculate the air gap change induced by the radial deformation of the rotor drum during the winding process of the wire rope;

[0012] S4. Establish a mechanical model of the stator core and calculate the air gap change induced by the radial deformation of the stator;

[0013] S5. Calculate the comprehensive change in air gap caused by the load borne by the rotor drum and stator core.

[0014] Further, step S1, specifically, establishes a Cartesian coordinate system yOz, the outer surface of the permanent magnet outer rotor hoist rotor drum is wound with a steel wire rope, the inner surface is equipped with a permanent magnet, the drum bearing surface width is L, and the axial length of the stator core is L ef The width of the permanent magnet surface area on the inner surface of the drum is L em When the wire rope is wound around the i-th circle, it enters the permanent magnet surface area, and when the j-th circle is wound around, it exits the permanent magnet surface area; the wire rope tension is F k (θ k ,t), the radial electromagnetic force generated by the permanent magnet on the inner surface of the drum is P k (θ k ,t), i≤k≤j, where θ k is the winding angle, θ k The range is [0,2π], N k (θ k ,t) is the wire rope tension F k (θ k ,t) The positive pressure generated on the roller surface.

[0015] Furthermore, in step S2, when a single layer and a single circle are wound, the tension of the wire rope changes in real time, and the radial force generated on the drum surface also changes in real time; when a single layer and a full circle are wound, the wire rope generates a uniform radial force on the drum surface when it completes a full circle in one layer of winding.

[0016] Further, step S2 is specifically,

[0017] S21. Calculate the real-time tension F of the steel wire rope during k turns of winding when winding a single layer and a single turn. k (θ k ,t) is:

[0018]

[0019] Among them, K rc is the mine damping coefficient, m1 is the lifting load mass, m t To increase the mass of the container, g is the acceleration due to gravity, m N is the approximate mass per unit length of the wire rope, H is the lifting height of the wire rope, R is the radius of the drum, θ k is the winding angle, ∑M k To improve the displacement quality of the system, a k(t) is the acceleration of the elevator operation;

[0020] S22, when the wire rope is wound in a single layer, the wire rope tension is F' when the wire rope is wound k times. k (θ k ,t) is:

[0021]

[0022] Among them, T0 is the maximum static tension of the wire rope; Q0 is the one-time lifting amount; m q is the displacement mass of the sky wheel; L s is the length of the wire rope; a k-1 (t) is the lifting acceleration after winding k-1 turns; t is the running time of the hoist;

[0023] S23, positive pressure N generated by wire rope tension on drum surface k (θ k ,t) is:

[0024]

[0025] Where τ is the wire rope groove pitch;

[0026] S24, the inner surface of the drum is subjected to radial electromagnetic force in any area of ​​area S:

[0027]

[0028] Where μ0 is the vacuum magnetic permeability, B mr is the radial magnetic flux density generated by the permanent magnet, B mθ is the tangential magnetic flux density;

[0029] S25. The resultant force on the roller is:

[0030] N rk (θ k ,t)=N k (θ k ,t)-P k (θ k ,t) (5).

[0031] Further, step S3 is specifically,

[0032] S31. Calculate the elastic foundation coefficient k ε for:

[0033]

[0034] Where h is the roller thickness, R is the roller radius, μ r is the Poisson's ratio of the roller material;

[0035] S32. Air gap change induced by radial deformation of the rotor drum during wire rope winding k (θ k ,t) is:

[0036]

[0037] Among them, N rk (θ k ,t) is the resultant force on the drum, E is the elastic modulus of the drum material, e is the natural logarithm, and the axial position z on the drum surface when the wire rope is wound around k turns k :z k =(k-1)τ, where τ is the groove pitch of the wire rope.

[0038] Further, in step S4, the air gap change induced by the radial deformation of the stator is calculated, specifically,

[0039] S41. The radial electromagnetic force on the top surface of the stator core teeth is a uniform load, which can be transmitted to the stator yoke. The stator slot does not bear the electromagnetic force. The radial electromagnetic force N is borne on the top of the stator core teeth. st (θ k ,t) is:

[0040]

[0041] Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, B sθ is the tangential magnetic flux density, S ef is the total area of ​​the stator core tooth tops, μ0 is the vacuum magnetic permeability;

[0042] S42, the radial electromagnetic force on the top of the stator core teeth is transmitted to the stator yoke, satisfying the lever arm effect. The electromagnetic force N sy (θ k ,t) is:

[0043]

[0044] Among them, R st is the stator core tooth tip radius, R sy is the radius of the stator core yoke;

[0045] S43. If the stator core-winding system is equivalent to a thin-walled ring, the elastic modulus of the combined material structure is:

[0046]

[0047] Among them, E s is the elastic modulus of the stator core material, E wis the elastic modulus of the stator winding, μ s is the Poisson's ratio of the stator core, μ w is the Poisson's ratio of the stator winding, φ s is the volume percentage of the stator core, φ w is the volume percentage of stator winding;

[0048] S44, air gap change induced by stator radial deformation s (θ k ,t) is:

[0049]

[0050] Among them, h s is the thickness of the equivalent thin-walled ring of the stator core yoke, L ef is the axial length of the stator core.

[0051] Further, step S5 is specifically,

[0052] Calculate the comprehensive change g of the air gap caused by the radial deformation of the rotor drum and the radial deformation of the stator core during the k turns of the wire rope rsk (θ k ,t):

[0053]

[0054] Where g0 is the initial air gap length, y s (θ k ,t) is the air gap change induced by the radial deformation of the stator, y k (θ k ,t) is the air gap change induced by the radial deformation of the rotor drum, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, E is the elastic modulus of the roller material, h is the roller thickness, N rk (θ k , t) is the resultant force borne by the roller; e is the natural logarithm.

[0055] Furthermore, the method further includes step S6, calculating the radial electromagnetic force wave of the permanent magnet outer rotor hoist caused by the comprehensive change of the air gap, specifically,

[0056] S61. Calculate the air gap permeability when considering the comprehensive change of the air gap;

[0057] S62. Calculate the radial electromagnetic force wave distribution when considering the comprehensive change of the air gap.

[0058] Further, step S61 is specifically,

[0059] Calculate the air gap permeability λ when the wire rope is wound k times and the air gap changes comprehensively rsk (θ k ,t) is:

[0060]

[0061] Where μ0 is the vacuum permeability, g rsk (θ k ,t) is the comprehensive change of air gap, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, N rk (θ k , t) is the resultant force on the roller, E is the elastic modulus of the roller material, h is the roller thickness, g0 is the initial air gap length, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, k ε is the elastic foundation coefficient, z k is the axial position of the wire rope on the drum surface when it is wound k turns, Λ0 is the air gap permeability constant when the slotting and air gap changes are not considered, and C1, C2 and C3 are constants.

[0062] Further, step S62 is specifically,

[0063] Calculate the radial electromagnetic force wave P when the wire rope is wound k times and the air gap changes comprehensively. rsk (θ k ,t) is:

[0064]

[0065] Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, P rsk (θ k ,t) contains 4 items in total. The first item is the radial electromagnetic force wave when the air gap change is not considered; the second item is the additional radial electromagnetic force wave caused by the air gap change caused by the magnetic field force of the stator yoke alone; the third item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum alone; the fourth item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum and the stator yoke, λ rsk (θ k ,t) is the air gap permeability when considering the comprehensive change of air gap, N sy (θ k ,t) and N rk (θ k , t) are the electromagnetic force borne by the stator yoke and the resultant force borne by the rotor drum, and C1, C2, and C3 are all constants.

[0066] The beneficial effects of the present invention are:

[0067] 1. Compared with the existing methods, this method for calculating the air gap change of a single-rope-wound permanent-magnet outer-rotor hoist under variable load can accurately calculate the real-time comprehensive air gap change of different types of single-rope-wound permanent-magnet outer-rotor hoists under variable speed conditions according to parameters such as load size, drum diameter and width, number of permanent-magnet poles, and number of stator slots. It can also quickly calculate the air gap change of the permanent-magnet outer-rotor hoist when the rotor and stator are subjected to radial deformation caused by variable loads. It can then calculate the influence of the comprehensive air gap change on the radial electromagnetic force wave, providing a reliable data basis for ensuring the smooth operation of the permanent-magnet outer-rotor hoist.

[0068] Second, the present invention establishes a mechanical model of the rotor drum based on two conditions: single-layer single-turn winding and single-layer full-turn winding, and realizes quantitative calculation of the force characteristics of the rotor drum of the series permanent magnet outer rotor hoist under complex working conditions. By simultaneously considering the positive pressure effect on the outer surface of the rotor drum during the dynamic winding of the wire rope and the effect of the radial component of the internal uniform periodic magnetic field force on the drum, it is possible to quickly calculate the radial deformation of the rotor drum during the dynamic winding of the wire rope.

[0069] 3. The calculation method of the air gap change of the single-rope wound permanent magnet outer rotor hoist under the action of variable load is aimed at the problem of calculating the out-of-roundness during the assembly process of the stator core of the large outer rotor permanent magnet outer rotor hoist. This method first equates the magnetic field force of the stator teeth to the uniformly distributed magnetic field force borne by the stator yoke, and uses the added mass method to equate the mass of the stator teeth to the stator yoke, and equates the entire stator core yoke to a thin-walled circular ring, and then obtains the radial deformation of the stator core under the action of periodic uniformly distributed electromagnetic force, realizing the load-bearing characteristics and radial deformation calculation of the stator system of the permanent magnet outer rotor hoist under variable speed conditions.

[0070] 4. The calculation method of the air gap change of the single-rope wound permanent magnet outer rotor hoist under the action of variable load establishes the coupling relationship between the dynamic radial deformation caused by the rotor drum and the stator core load and the air gap change of the motor, realizes the rapid conversion of the load and the internal air gap change of the permanent magnet outer rotor hoist during operation, and realizes the rapid calculation of the air gap change, which is conducive to real-time monitoring of the air gap change to realize the identification and early warning of abnormal working conditions.

[0071] 5. This method for calculating the change in the air gap of a single-rope wound permanent magnet outer rotor hoist under variable load can realize the rapid calculation of radial electromagnetic force waves under the condition of non-uniform change in the air gap of the permanent magnet outer rotor hoist, which is conducive to real-time grasp of the impact of load changes on the magnetic field, and then realize accurate evaluation of the stability of the magnetic field during the operation of the permanent magnet outer rotor hoist. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a flow chart of a method for calculating the change in the air gap of a single-rope-wound permanent magnet outer rotor hoist under variable load according to an embodiment of the present invention;

[0073] Figure 2 Schematic diagram of the mechanical model of the rotor drum of the permanent magnet outer rotor hoist in the embodiment;

[0074] Figure 3 In the embodiment, the positive pressure N generated by the tension of the wire rope on the drum surface is generated by the permanent magnet outer rotor hoist rotor drum k (θ k ,t) distribution diagram;

[0075] Figure 4 Schematic diagram of the mechanical model of the stator core of the permanent magnet outer rotor hoist in the embodiment;

[0076] Figure 5 Schematic diagram of the air gap flux density generated by the permanent magnets of the permanent magnet outer rotor hoisting machine rotor in the embodiment, wherein (a) is the radial air gap flux density B generated by the permanent magnets of the permanent magnet outer rotor hoisting machine rotor mr , (b) is the tangential air gap flux density B generated by the permanent magnet of the permanent magnet outer rotor hoist rotor mθ ;

[0077] Figure 6 is the positive pressure N generated by the wire rope tension on the drum surface in the embodiment k (θ k ,t) When the permanent magnet outer rotor hoist rotor drum is at its maximum, it is subjected to the internal magnetic field force P k (θ k ,t) distribution diagram;

[0078] Figure 7 Schematic diagram of the air gap flux density generated by the armature winding of the permanent magnet outer rotor hoist in the embodiment, wherein (a) is the radial air gap flux density B generated by the armature winding of the permanent magnet outer rotor hoist sr Schematic diagram of (b) is the tangential air gap flux density B generated by the armature winding of the permanent magnet outer rotor hoist sθ Schematic diagram of

[0079] Figure 8 is the electromagnetic force N borne by the stator yoke of the permanent magnet outer rotor hoist in the embodiment sy (θ k ,t) distribution diagram;

[0080] Fig. 9 is the positive pressure N generated by the wire rope tension on the drum surface in the embodiment k (θ k,t) is the maximum when considering the radial deformation of the stator and rotor, the comprehensive change of the air gap of the permanent magnet outer rotor hoist g rsk (θ k ,t) distribution diagram;

[0081] Fig.10 is the positive pressure N generated by the wire rope tension on the drum surface in the embodiment k (θ k ,t) is the maximum when considering the radial electromagnetic force wave P before and after the comprehensive change of the air gap of the permanent magnet outer rotor hoist rsk (θ k ,t) distribution diagram;

[0082] Among them: 1- drum; 2- steel wire rope; 3- permanent magnet; 4- stator tooth top; 5- stator tooth body; 6- stator yoke. DETAILED DESCRIPTION

[0083] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0084] The embodiment provides a method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load, such as Figure 1 , including the following steps,

[0085] S1. Establish a mechanical model of the rotor drum of a single-rope-wound permanent magnet outer rotor hoist under variable speed and variable load conditions; specifically, Figure 2 , establish the Cartesian coordinate system yOz, the outer surface of the permanent magnet outer rotor hoist rotor drum 1 is wrapped with a steel wire rope 2, and the inner surface is equipped with a permanent magnet 3. The width of the drum bearing surface is L, and the axial length of the stator core is L ef The width of the permanent magnet surface area on the inner surface of the drum is L em When the wire rope is wound around the i-th circle, it enters the permanent magnet surface area, and when the j-th circle is wound around, it exits the permanent magnet surface area; the wire rope tension is F k (θ k ,t), the radial electromagnetic force generated by the permanent magnet 3 on the inner surface of the drum is P k (θ k ,t), i≤k≤j, where θ k is the winding angle, θ k The range is [0,2π], N k (θ k ,t) is the wire rope tension F k (θ k ,t) The positive pressure generated on the drum surface. The mechanical model of the rotor drum of the permanent magnet outer rotor hoist is mainly for the permanent magnet 2 assembly area when the wire rope is wound around the i-jth circle.

[0086] S2. Calculate the external wire rope positive pressure, including the positive pressure generated by the wire rope tension on the drum surface under two working conditions: single-layer single-turn winding and single-layer full-turn winding, and calculate the internal radial electromagnetic force. Solve for the resultant force on the drum when considering the combined influence of the external wire rope positive pressure and the internal radial electromagnetic force.

[0087] In step S2, when a single layer and single turn are wound, the wire rope tension changes in real time, and the radial force generated on the drum surface also changes in real time. k The value range of is (0, 2kπ), i≤k≤j; when the wire rope is wound in a single layer, the uniform radial force on the drum surface is generated when the wire rope is wound in a single layer. k The value range of is 2kπ.

[0088] Step S2 is specifically,

[0089] S21. Calculate the real-time tension F of the steel wire rope during k turns of winding when winding a single layer and a single turn. k (θ k ,t) is:

[0090]

[0091] Among them, K rc is the mine damping coefficient, m1 is the lifting load mass, m t To increase the mass of the container, g is the acceleration due to gravity, m N is the approximate mass per unit length of the wire rope, H is the lifting height of the wire rope, R is the radius of the drum, θ k is the winding angle, ∑M k To improve the displacement quality of the system, a k (t) is the acceleration of the elevator operation;

[0092] S22, when the wire rope is wound in a single layer, the wire rope tension is F' when the wire rope is wound k times. k (θ k ,t) is:

[0093]

[0094] Among them, T0 is the maximum static tension of the wire rope; Q0 is the one-time lifting amount; m q is the displacement mass of the sky wheel; L s is the length of the wire rope; a k-1 (t) is the lifting acceleration after winding k-1 turns; t is the running time of the hoist;

[0095] S23, positive pressure N generated by wire rope tension on drum surface k (θ k ,t) is:

[0096]

[0097] Where τ is the wire rope groove pitch;

[0098] S24, the inner surface of the drum is subjected to radial electromagnetic force in any area of ​​area S:

[0099]

[0100] Where μ0 is the vacuum magnetic permeability, B mr is the radial magnetic flux density generated by the permanent magnet, B mθ is the tangential magnetic flux density;

[0101] S25. The resultant force on the roller is:

[0102] N rk (θ k ,t)=N k (θ k ,t)-P k (θ k ,t) (5).

[0103] In step S2, a mechanical model of the rotor drum is established based on two conditions: single-layer single-turn winding and single-layer full-turn winding. When single-layer single-turn winding is used, in the permanent magnet surface area, the wire rope tension is regarded as an external load that changes continuously with time, angle, and axial position, and the internal magnetic field force is a local periodic uniformly distributed load; when single-layer full-turn winding is used, in the permanent magnet surface area, at the moment when the wire rope is wound around any circle, the wire rope tension is regarded as a uniformly distributed force distributed along the circumferential direction of the outer surface of the drum, and changes with the change of the number of winding circles, and the internal magnetic field force is an overall periodic uniformly distributed load. This method realizes the quantitative calculation of the force characteristics of the rotor drum of the serialized permanent magnet outer rotor hoist under complex working conditions.

[0104] S3. Calculate the air gap change caused by the radial deformation of the rotor drum during the winding process of the wire rope.

[0105] S31. Calculate the elastic foundation coefficient k ε for:

[0106]

[0107] Where h is the roller thickness, R is the roller radius, μ r is the Poisson's ratio of the roller material;

[0108] S32. Air gap change induced by radial deformation of the rotor drum during wire rope winding k (θ k ,t) is:

[0109]

[0110] Among them, N rk (θ k ,t) is the resultant force on the drum, E is the elastic modulus of the drum material, e is the natural logarithm, and the axial position z on the drum surface when the wire rope is wound around k turns k :z k =(k-1)τ, where τ is the groove pitch of the wire rope.

[0111] S4. Establish a mechanical model of the stator core and calculate the air gap change caused by the radial deformation of the stator core.

[0112] In step S4, the air gap change induced by the radial deformation of the stator is calculated, specifically:

[0113] S41. The radial electromagnetic force on the top surface of the stator core teeth is a uniform load, which can be transmitted to the stator yoke. The stator slot does not bear the electromagnetic force. The radial electromagnetic force N is borne on the top of the stator core teeth. st (θ k ,t) is:

[0114]

[0115] Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, B sθ is the tangential magnetic flux density, S ef is the total area of ​​the stator core tooth tops, μ0 is the vacuum magnetic permeability;

[0116] S42, the radial electromagnetic force on the top of the stator core teeth is transmitted to the stator yoke, satisfying the lever arm effect. The electromagnetic force N sy (θ k ,t) is:

[0117]

[0118] Among them, R st is the stator core tooth tip radius, R sy is the radius of the stator core yoke;

[0119] S43. If the stator core-winding system is equivalent to a thin-walled ring, the elastic modulus of the combined material structure is:

[0120]

[0121] Among them, E s is the elastic modulus of the stator core material, E w is the elastic modulus of the stator winding, μ s is the Poisson's ratio of the stator core, μ wis the Poisson's ratio of the stator winding, φ s is the volume percentage of the stator core, φ w is the volume percentage of stator winding;

[0122] S44, air gap change induced by stator radial deformation s (θ k ,t) is:

[0123]

[0124] Among them, h s is the thickness of the equivalent thin-walled ring of the stator core yoke, L ef is the axial length of the stator core.

[0125] In step S4, in order to solve the problem of out-of-roundness calculation during the assembly process of the stator core of a large outer rotor permanent magnet outer rotor hoist, the magnetic field force of the stator teeth is firstly equivalent to the uniformly distributed magnetic field force borne by the stator yoke, and the mass of the stator teeth is equivalent to the stator yoke by the added mass method, and the entire stator core yoke is equivalent to a thin-walled circular ring, and then the radial deformation of the stator core under the action of periodic uniformly distributed electromagnetic force is obtained, realizing the load-bearing characteristics and radial deformation calculation of the stator system of the permanent magnet outer rotor hoist under variable speed conditions.

[0126] S5. Calculate the comprehensive change in air gap caused by the load borne by the rotor drum and stator core.

[0127] Calculate the comprehensive change g of the air gap caused by the radial deformation of the rotor drum and the radial deformation of the stator core during the k turns of the wire rope rsk (θ k ,t):

[0128]

[0129] Where g0 is the initial air gap length, y s (θ k ,t) is the air gap change induced by the radial deformation of the stator, y k (θ k ,t) is the air gap change induced by the radial deformation of the rotor drum, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, E is the elastic modulus of the roller material, h is the roller thickness, N rk (θ k , t) is the resultant force borne by the roller; e is the natural logarithm.

[0130] The step S6 is also included, calculating the radial electromagnetic force wave of the permanent magnet outer rotor hoist caused by the comprehensive change of the air gap, specifically,

[0131] S61, calculate the air gap permeance when considering the comprehensive change of the air gap; specifically, calculate the air gap permeance λ when considering the comprehensive change of the air gap during the process of winding the wire rope k turns rsk (θ k ,t) is:

[0132]

[0133] Where μ0 is the vacuum permeability, g rsk (θ k ,t) is the comprehensive change of air gap, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, N rk (θ k , t) is the resultant force on the roller, E is the elastic modulus of the roller material, h is the roller thickness, g0 is the initial air gap length, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, k ε is the elastic foundation coefficient, z k is the axial position of the wire rope on the drum surface when it is wound k turns, Λ0 is the air gap permeability constant when the slotting and air gap changes are not considered, and C1, C2 and C3 are constants.

[0134] S62, calculate the radial electromagnetic force wave distribution when considering the comprehensive change of the air gap; specifically, calculate the radial electromagnetic force wave P when considering the comprehensive change of the air gap during the winding process of the wire rope k turns. rsk (θ k ,t) is:

[0135]

[0136] Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, P rsk (θ k ,t) contains 4 items in total. The first item is the radial electromagnetic force wave when the air gap change is not considered; the second item is the additional radial electromagnetic force wave caused by the air gap change caused by the magnetic field force of the stator yoke alone; the third item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum alone; the fourth item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum and the stator yoke, λ rsk (θ k ,t) is the air gap permeability when considering the comprehensive change of air gap, N sy (θ k ,t) and N rk (θk , t) are the electromagnetic force borne by the stator yoke and the resultant force borne by the rotor drum, and C1, C2, and C3 are all constants.

[0137] Step S6 realizes the rapid calculation of radial electromagnetic force waves under the condition of non-uniform change of the air gap of the permanent magnet outer rotor hoist, which is conducive to real-time understanding of the impact of load changes on the magnetic field, and further realizes accurate evaluation of the stability of the magnetic field during the operation of the permanent magnet outer rotor hoist.

[0138] Compared with the existing methods, this method for calculating the air gap change of a single-rope-wound permanent-magnet outer-rotor hoist under variable load can accurately calculate the real-time comprehensive air gap change of different types of single-rope-wound permanent-magnet outer-rotor hoists under variable speed conditions according to parameters such as load size, drum diameter and width, number of permanent-magnet poles, and number of stator slots. It can also quickly calculate the air gap change of the permanent-magnet outer-rotor hoist when the rotor and stator are subjected to radial deformation caused by variable loads. Furthermore, it can calculate the influence of the comprehensive air gap change on the radial electromagnetic force wave, providing a reliable data basis for ensuring the smooth operation of the permanent-magnet outer-rotor hoist.

[0139] The calculation method of the air gap change of the single-rope wound permanent magnet outer rotor hoist under the action of the variable load in the embodiment is described as follows by taking the JKN2.5×2P single-rope wound permanent magnet outer rotor hoist as an example:

[0140] Maximum static tension of wire rope T0: T0 = 90kN; Mine damping coefficient K rc :K rc =1.1; lifting load mass m1: m1 = 10000kg; lifting container mass m t :m t =10000kg, gravitational acceleration g: g = 9.81m / s 2 ; One-time lifting amount Q0: Q0 = 23000kg; Approximate mass per unit length of wire rope m N :m N =3.762kg / m; wire rope lifting height H: H = 550m; drum radius R: R = 1.25m; head sheave displacement mass m q :m q =2000kg; lifting system displacement mass ∑M k :∑M k =12500kg; wire rope length L s :L s =20m; elevator running acceleration a k (t), the steel wire rope has entered the uniform speed running section after winding in the permanent magnet assembly area, a k (t) = 0. The width of the permanent magnet surface area on the inner surface of the drum is L em :Lem =1200mm, radial magnetic flux density B generated by permanent magnet rm , tangential magnetic flux density B θm , vacuum magnetic permeability μ0: μ0=4π×10 -7 H / m.

[0141] S1. Establish the mechanical model of the rotor drum of a single-rope-wound permanent magnet outer rotor hoist under variable speed and variable load conditions, such as Figure 2 .

[0142] S2. Calculate the external wire rope positive pressure, including the positive pressure generated by the wire rope tension on the drum surface under two working conditions: single-layer single-turn winding and single-layer full-turn winding, and calculate the internal radial electromagnetic force. Solve for the resultant force on the drum when considering the combined influence of the external wire rope positive pressure and the internal radial electromagnetic force.

[0143] In step S2, the positive pressure N generated by the tension of the wire rope on the drum surface during the process of winding the wire rope k turns is k (θ k ,t) can be obtained from equations (1) to (3), and its distribution is as follows: Figure 3 It can be seen that the steel wire rope enters the permanent magnet surface area at the 10th winding and exits at the 46th winding. The dynamic tension of the steel wire rope decreases with the increase of winding number, and the decrease amplitude increases with the increase of winding angle. Therefore, when k = 10, N k (θ k ,t) is maximum. In addition, the radial air gap flux density B generated by the permanent magnet of the permanent magnet outer rotor lifter rotor mr The distribution of Figure 5 (a), the tangential air gap flux density B generated by the permanent magnet of the permanent magnet outer rotor hoist mθ The distribution of Figure 5 (b), the inner surface of the drum is cut into regions with a step length equal to the rope groove pitch, so that the radial forces on the inner and outer surfaces of the drum are collinear. Based on formula (4) and using the field calculator, the electromagnetic force calculation equation on each winding area of ​​the wire rope is established, and B mr and B mθ By substituting the numerical values ​​into the equation, we can quickly calculate the magnetic field force on the inner surface of the drum during each circle of the wire rope wrapped around the drum surface. Figure 6 The normal pressure N generated by the wire rope tension on the drum surface is given as k (θ k ,t) is maximum (k=10), the rotor drum of the permanent magnet outer rotor hoist is subjected to the internal magnetic field force P k (θ k ,t)(k=10)distribution.

[0144] S3. Calculate the air gap change caused by the radial deformation of the rotor drum during the winding process of the wire rope.

[0145] In step S3, the roller thickness h: h = 30 mm; the roller material Poisson's ratio μ r :μ r =0.3; elastic modulus E of the drum material: E = 210 GPa; axial position z on the drum surface when the wire rope is wound around k turns k , 0mm≤z k ≤1200mm

[0146] S4. Establish the mechanical model of the stator core, such as Figure 4 , and calculate the air gap change induced by the stator radial deformation.

[0147] In step S4, the axial length L of the stator core ef :L ef =1200mm; total area of ​​stator core tooth top S ef :S ef =2.8m 2 ; Stator core tooth tip radius R st : R st =825mm; stator core yoke radius R sy : R sy =695mm; elastic modulus of the stator core material E s :E s =206GPa; Stator winding elastic modulus E w :E s =117GPa; Poisson's ratio of stator core μ s :μ s =0.29; Poisson's ratio of stator winding μ w :μ w =0.31; stator core volume percentage φ s :φ s =82.8%; stator winding volume percentage φ w :φ w =17.2%; the thickness of the equivalent thin-walled ring of the stator core yoke h s :h s =10mm; initial air gap length g0: g0=3mm. The radial air gap flux density B generated by the armature winding of the permanent magnet outer rotor hoist is calculated. sr like Figure 7 (a), the tangential air gap flux density B generated by the armature winding of the permanent magnet outer rotor hoist sθ like Figure 7 (b); Calculate the electromagnetic force N on the stator yoke of the permanent magnet outer rotor hoist sy (θ k,t) Figure 8 .

[0148] S5. Calculate the comprehensive change in the air gap caused by the load borne by the rotor drum and the stator core. According to formula (12), it can be quickly obtained that during the operation of the hoist, when the wire rope is in the permanent magnet surface area, during any winding process, the comprehensive change in the air gap caused by the load borne by the rotor drum and the stator core changes with the winding angle. Extract the comprehensive change in the air gap g of the permanent magnet outer rotor hoist at the axial position when the radial deformation of the stator and rotor is the maximum. rsk (θ k ,t) is distributed as Fig. 9 , it can be seen that the maximum air gap change △r of this embodiment max The minimum air gap change is 0.354mm. min It is 0.351mm.

[0149] S6. Calculate the radial electromagnetic force wave of the permanent magnet outer rotor hoist caused by the comprehensive change of the air gap. The results are as follows Fig.10 It can be seen that under ideal air gap conditions, the radial electromagnetic force wave is relatively uniform, while the radial electromagnetic force wave under air gap change conditions caused by two inducements produces large fluctuations on the adjacent two-pole permanent magnets. Obviously, the air gap change will have a significant impact on the radial electromagnetic force wave. Therefore, it is very important to master the real-time change of the air gap of the permanent magnet outer rotor hoist during operation.

[0150] The present invention establishes a mechanical model of the rotor drum based on two conditions: single-layer single-turn winding and single-layer full-turn winding, and realizes quantitative calculation of the force characteristics of the rotor drum of the series permanent magnet outer rotor hoist under complex working conditions. By simultaneously considering the positive pressure effect on the outer surface of the rotor drum during the dynamic winding of the wire rope and the effect of the radial component of the internal uniform periodic magnetic field force on the drum, the radial deformation of the rotor drum during the dynamic winding of the wire rope can be quickly calculated.

[0151] This method for calculating the air gap change of a single-rope wound permanent magnet outer rotor hoist under variable load establishes a coupling relationship between the dynamic radial deformation caused by the rotor drum and stator core load and the motor air gap change, realizes the rapid conversion of the load and internal air gap change of the permanent magnet outer rotor hoist during operation, and realizes the rapid calculation of the air gap change, which is conducive to real-time monitoring of the air gap change to realize the identification and early warning of abnormal working conditions. This method is suitable for single-rope wound mine hoists, especially for the calculation of air gap change of permanent magnet outer rotor mine hoists running at low speed and high torque when the outer rotor drum is subjected to time-varying heavy loads.

[0152] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load, characterized in that: The following steps are included: S1. Establish the mechanical model of the rotor drum of a single-rope-wound permanent magnet outer rotor hoist under variable speed and variable load conditions; S2. Calculate the positive pressure of the external wire rope, including the positive pressure generated by the wire rope tension on the drum surface under two working conditions: single-layer single-turn winding and single-layer full-turn winding, and calculate the internal radial electromagnetic force, and solve the resultant force on the drum when considering the combined influence of the external wire rope positive pressure and the internal radial electromagnetic force; S3. Calculate the air gap change caused by the radial deformation of the rotor drum during the winding process of the wire rope S4. Establish a mechanical model of the stator core and calculate the air gap change induced by the radial deformation of the stator; S5. Calculate the comprehensive change in air gap caused by the load borne by the rotor drum and stator core.

2. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 1, characterized in that: Step S1, specifically, establish a Cartesian coordinate system yOz, the outer surface of the permanent magnet outer rotor hoist rotor drum is wound with a steel wire rope, the inner surface is equipped with a permanent magnet, the drum bearing surface width is L, and the axial length of the stator core is L ef The width of the permanent magnet surface area on the inner surface of the drum is L em When the wire rope is wound around the i-th circle, it enters the permanent magnet surface area, and when the j-th circle is wound around, it exits the permanent magnet surface area; the wire rope tension is F k (θ k ,t), the radial electromagnetic force generated by the permanent magnet on the inner surface of the drum is P k (θ k ,t), i≤k≤j, where θ k is the winding angle, θ k The range is [0,2π], N k (θ k ,t) is the wire rope tension F k (θ k ,t) The positive pressure generated on the roller surface.

3. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 1, characterized in that: In step S2, when a single layer and a single circle are wound, the tension of the wire rope changes in real time, and the radial force generated on the drum surface also changes in real time; when a single layer and a full circle are wound, the wire rope generates a uniform radial force on the drum surface when it is wound a full circle in one layer.

4. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 1, characterized in that: Step S2 is specifically, S21. Calculate the real-time tension F of the steel wire rope during k turns of winding when winding a single layer and a single turn. k (θ k ,t) is: Among them, K rc is the mine damping coefficient, m1 is the lifting load mass, m t To increase the mass of the container, g is the acceleration due to gravity, m N is the approximate mass per unit length of the wire rope, H is the lifting height of the wire rope, R is the radius of the drum, θ k is the winding angle, ∑M k In order to improve the displacement quality of the system, a k (t) is the acceleration of the elevator operation; S22, when the wire rope is wound in a single layer, the wire rope tension is F' when the wire rope is wound k times. k (θ k ,t) is: Among them, T0 is the maximum static tension of the wire rope; Q0 is the one-time lifting amount; m q L is the displacement mass of the sky wheel; s is the length of the wire rope; a k-1 (t) is the lifting acceleration after winding k-1 turns; t is the running time of the hoist; S23, positive pressure N generated by wire rope tension on drum surface k (θ k ,t) is: Where, τ is the wire rope groove pitch; S24, the inner surface of the drum is subjected to radial electromagnetic force in any area of ​​area S: Where μ0 is the vacuum magnetic permeability, B mr is the radial magnetic flux density generated by the permanent magnet, B mθ is the tangential magnetic flux density; S25. The resultant force on the roller is: N rk (i k ,t)=N k (i k ,t)-P k (i k ,t) (5).

5. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 4, characterized in that: Step S3, specifically, S31. Calculate the elastic foundation coefficient k ε for: Where h is the roller thickness, R is the roller radius, μ r is the Poisson's ratio of the roller material; S32. Air gap change induced by radial deformation of the rotor drum during wire rope winding k (θ k ,t) is: Among them, N rk (θ k ,t) is the resultant force on the drum, E is the elastic modulus of the drum material, e is the natural logarithm, and the axial position z on the drum surface when the wire rope is wound around k turns k :z k =(k-1)τ, where τ is the groove pitch of the wire rope.

6. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load according to any one of claims 1 to 5, characterized in that: In step S4, the air gap change caused by the radial deformation of the stator core is calculated, specifically, S41. The radial electromagnetic force on the top surface of the stator core teeth is a uniform load, which can be transmitted to the stator yoke. The stator slot does not bear the electromagnetic force. The radial electromagnetic force N is borne on the top of the stator core teeth. st (θ k ,t) is: Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, B sθ is the tangential magnetic flux density, S ef is the total area of ​​the stator core tooth tops, μ0 is the vacuum magnetic permeability; S42, the radial electromagnetic force on the top of the stator core teeth is transmitted to the stator yoke, satisfying the lever arm effect. The electromagnetic force N sy (θ k ,t) is: Among them, R st is the stator core tooth tip radius, R sy is the radius of the stator core yoke; S43. If the stator core-winding system is equivalent to a thin-walled ring, the elastic modulus of the combined material structure is: Among them, E s is the elastic modulus of the stator core material, E w is the elastic modulus of the stator winding, μ s is the Poisson's ratio of the stator core, μ w is the Poisson's ratio of the stator winding, φ s is the volume percentage of the stator core, φ w is the volume percentage of stator winding; S44, air gap change induced by stator radial deformation s (θ k ,t) is: Among them, h s is the thickness of the equivalent thin-walled ring of the stator core yoke, L ef is the axial length of the stator core.

7. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as described in any one of claims 1 to 5, characterized in that: Step S5, specifically, Calculate the comprehensive change g of the air gap caused by the radial deformation of the rotor drum and the radial deformation of the stator core during the k turns of the wire rope rsk (θ k ,t): Where g0 is the initial air gap length, y s (θ k ,t) is the air gap change induced by the radial deformation of the stator, y k (θ k ,t) is the air gap change induced by the radial deformation of the rotor drum, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, E is the elastic modulus of the roller material, h is the roller thickness, N rk (θ k , t) is the resultant force borne by the roller; e is the natural logarithm.

8. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load according to any one of claims 1 to 5, characterized in that: The step S6 is also included, calculating the radial electromagnetic force wave of the permanent magnet outer rotor hoist caused by the comprehensive change of the air gap, specifically, S61. Calculate the air gap permeability when considering the comprehensive change of the air gap; S62. Calculate the radial electromagnetic force wave distribution when considering the comprehensive change of the air gap.

9. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 8, characterized in that: Step S61, specifically, Calculate the air gap permeability λ when the wire rope is wound k times and the air gap changes comprehensively rsk (θ k ,t) is: Where μ0 is the vacuum magnetic permeability, g rsk (θ k ,t) is the comprehensive change of air gap, N sy (θ k ,t) is the electromagnetic force borne by the stator yoke, N rk (θ k , t) is the resultant force on the roller, E is the elastic modulus of the roller material, h is the roller thickness, g0 is the initial air gap length, R st L is the radius of the stator core tooth tip, ef is the axial length of the stator core, k ε is the elastic foundation coefficient, z k is the axial position of the wire rope on the drum surface when it is wound k turns, Λ0 is the air gap permeability constant when the slotting and air gap changes are not considered, and C1, C2 and C3 are constants.

10. The method for calculating the air gap change of a single-rope-wound permanent magnet outer rotor hoist under variable load as claimed in claim 9, characterized in that: Step S62 is specifically, Calculate the radial electromagnetic force wave P when the wire rope is wound k times and the air gap changes comprehensively. rsk (θ k ,t) is: Among them, B sr is the radial magnetic flux density of the stator armature winding magnetic field, P rsk (θ k ,t) contains 4 items in total. The first item is the radial electromagnetic force wave when the air gap change is not considered; the second item is the additional radial electromagnetic force wave caused by the air gap change caused by the magnetic field force of the stator yoke alone; the third item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum alone; the fourth item is the additional radial electromagnetic force wave caused by the air gap change caused by the combined force of the rotor drum and the stator yoke, λ rsk (θ k ,t) is the air gap permeability when considering the comprehensive change of air gap, N sy (θ k ,t) and N rk (θ k , t) are the electromagnetic force borne by the stator yoke and the resultant force borne by the rotor drum, and C1, C2, and C3 are all constants.

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