Modularized permanent magnet motor

Abstract

The utility model discloses a modularized permanent magnet motor which comprises a modularized stator, a coil and a rotor. The modularized stator comprises a stator module I, a stator module II, a stator module III and a stator module IV which are connected with one another; the coils are embedded and distributed in stator grooves of the modular stator, and at least one group of coils belonging to A, B and C phases respectively are removed from each stator module; the rotor comprises a plurality of rotor magnetic poles, magnetic steel grooves are formed among the rotor magnetic poles, the permanent magnets are bonded in the magnetic steel grooves, the permanent magnets are bonded with the magnetic isolation rings, the rotor magnetic poles are fixed on the magnetic isolation rings and the supporting cylinder, and an air gap is formed between the modular stator and the rotor. The coil removal modularization technology is applied to the large ball mill direct-driven permanent magnet motor, and the problems that manufacturing, transportation, disassembly and maintenance are difficult due to the fact that the size of the large permanent magnet motor applied to a high-power large-torque direct-driven system is too large are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field especially relates to a modular permanent magnet motor. BACKGROUND

[0002] Permanent magnet direct drive ball mill set has many advantages such as high driving efficiency, large torque density, low maintenance cost, long service life and good low-high voltage crossing performance, and the technology has developed rapidly in recent years. However, with the increase of single power of ball mill driving motor set, the diameter of direct drive motor becomes larger and larger, and production and manufacturing equipment, transportation and fault maintenance become the biggest bottleneck problem restricting the technology. Improving the power density of the motor and the modularization level of production and manufacturing is an inevitable trend of the industry development. At present, the maximum width limit of land transportation is about 5m, and exceeding the transportation limit will greatly increase the transportation cost and even be unachievable, thus bringing great challenges to the economic design of the motor.

[0003] The modular permanent magnet motor has the advantages of low speed, large torque, high reliability and flexible manufacturing, and is suitable for use in mine mechanical equipment. The traditional torque distribution method is generally torque equal distribution, that is, the total torque of the motor is equally distributed to each stator module to obtain the corresponding stator current. However, under the condition of variable load, this method cannot guarantee that the motor always works in high efficiency state, resulting in low overall efficiency of the system.

[0004] In summary, under the condition of variable load operation, the equal torque distribution method can only keep the modular permanent magnet motor in the highest efficiency state in the rated load area, and cannot keep high efficiency operation in the entire load area. SUMMARY

[0005] The utility model discloses in order to overcome the deficiency that permanent magnet motor can only keep high efficiency operation in specific load area under the condition of variable load, and proposes a kind of modular permanent magnet motor.

[0006] To solve the above technical problems, the technical scheme of the utility model is as follows: a kind of modular permanent magnet motor, including modular stator, coil and rotor;Modular stator includes the stator module one, stator module two, stator module three, stator module four connected;Coil is embedded in the stator slot of modular stator, and at least one group of coils belonging to A, B, C three phases is removed in each stator module;Rotor includes a plurality of rotor magnetic poles, and magnetic steel slot is formed between rotor magnetic pole, permanent magnet is bonded in magnetic steel slot, permanent magnet is bonded with magnetic separation ring, rotor magnetic pole is fixed on magnetic separation ring, support cylinder, and air gap is formed between modular stator and rotor.

[0007] Further, the permanent magnet is bonded in the magnetic steel slot by epoxy resin adhesive.

[0008] Further, the permanent magnet is bonded with the magnetic separation ring by epoxy resin adhesive.

[0009] Further, the removed coils of each stator module belong to at least one group of A, B and C three phases, the number of removed coils r=3ks, k=1, 2, 3, …, s is the number of stator modules; the modular stator adopts a true fraction slot concentrated winding, and one sub-module is from one removed coil stator slot to the next removed coil stator slot, and the number of slots is Z r =12·(b / 6+c) and Z r =Z / r; wherein Z is the number of stator slots, r is the same as the number of removed coils and sub-modules, b=1, 2, 4, 5 is an integer satisfying the stator block rule, and c=0, 1, 2, 3, … is a natural number.

[0010] An efficiency optimization torque distribution control method of a modular permanent magnet motor, a low load area P set1 , l=1, one module is put into operation, that is, any one of the first stator module, the second stator module, the third stator module and the fourth stator module; a second low load area P set2 , l=2, two symmetrical modules are put into operation, that is, any two of the first stator module and the third stator module or the second stator module and the fourth stator module; a second high load area P set3 , l=3, three modules are put into operation, that is, any three of the first stator module, the second stator module, the third stator module and the fourth stator module; a high load area P set4 , l=4, all four modules are put into operation, that is, the first stator module, the second stator module, the third stator module and the fourth stator module are all operated; so as to ensure that the motor always works in a high efficiency state under variable load.

[0011] The beneficial effects of the utility model are as follows:

[0012] 1. The removed coil modularization technology is applied to the large-scale ball mill direct drive permanent magnet motor, and problems such as manufacturing, transportation, disassembly and maintenance difficulty caused by the large size of the large-scale permanent magnet motor applied to the high-power and large-torque direct drive system are solved.

[0013] 2. The efficiency optimization torque distribution control method is applied to the efficiency optimization of the modular permanent magnet motor, and the high efficiency interval of the motor under variable load can be maximally widened. DRAWINGS

[0014] In order to more clearly illustrate the technical scheme of the utility model or related technology, the drawings needed to be used in the following embodiment or related technology description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the utility model, and other drawings can also be obtained by those skilled in the art without creative labor.

[0015] Figure 1 It is a structural schematic diagram of the utility model;

[0016] Figure 2 is a structure schematic diagram of a stator module one of the utility model;

[0017] Figure 3 is a structure schematic diagram of a rotor corresponding to a stator module one of the utility model;

[0018] Figure 4 is a no-load back EMF simulation result diagram;(a) all module operation no-load back EMF;(b) part of module operation no-load back EMF;

[0019] Figure 5 is a stator maximum deformation cloud picture under different module number operation under rated current;(a) all module operation;(b) three module operation;(c) two symmetrical module operation;(d) one module operation;

[0020] Figure 6 is the efficiency distribution of different load under different module number input:(a) three-dimensional distribution;(b) two-dimensional distribution;

[0021] Figure 7 is an efficiency optimization torque distribution control block diagram of the utility model;

[0022] Figure 8 is the efficiency curve of all torque distribution and efficiency optimization torque distribution control under different load.

[0023] Wherein: 1, modular stator;1-1, stator module one;1-2, stator module two;1-3, stator module three;1-4, stator module four;1-5, sub module;2, coil;3, rotor;3-1, rotor magnetic pole;3-2, permanent magnet;3-3, magnetic ring;4, support cylinder. DETAILED DESCRIPTION

[0024] The technical scheme of the utility model will be described clearly and completely below, obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor are within the protection scope of the utility model. Figures 1-8 The utility model will be described in detail below through specific embodiment, but it is not limited to the protection scope of the utility model. If there is no special description, the experimental method adopted in the utility model is all conventional method, and the experimental apparatus, material, reagent etc. used can be obtained from commercial channel.

[0025] The utility model will be described in detail below through specific embodiment, but it is not limited to the protection scope of the utility model. If there is no special description, the experimental method adopted in the utility model is all conventional method, and the experimental apparatus, material, reagent etc. used can be obtained from commercial channel.

[0026] In the description of the utility model, it needs to explain, the term "vertical", "horizontal", "inner", "outer" and so on indicate the position relation or location relation is based on the position relation or location relation shown in the drawing, only for the convenience of describing the utility model and simplifying the description, and not indicate or imply that the indicated device or component must have a particular orientation, construct and operate in a particular orientation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only used for distinction, and cannot be understood as indicating or implying relative importance.

[0027] In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as there is no conflict between them.

[0028] A modular permanent magnet motor, comprising a modular stator 1, a coil 2 and a rotor 3, the modular stator 1 comprises a stator module one 1-1, a stator module two 1-2, a stator module three 1-3 and a stator module four 1-4 connected in series, the coil 2 is embedded and distributed in the stator slot of the modular stator 1, at least one group of coils 2 belonging to A, B and C three phases are removed from each stator module, the rotor 3 comprises a plurality of rotor magnetic poles 3-1, a magnetic steel slot is formed between the rotor magnetic poles 3-1, a permanent magnet 3-2 is bonded in the magnetic steel slot through an epoxy resin adhesive, the permanent magnet 3-2 is bonded with a magnetic separation ring 3-3 through the epoxy resin adhesive, the rotor magnetic pole 3-1 is fixed on the magnetic separation ring 3-3 and a support cylinder 4, and an air gap is formed between the modular stator 1 and the rotor 3.

[0029] The removed coil 2 of each stator module belongs to at least one group of A, B and C three phases, the number of removed coils r=3ks, k=1, 2, 3, …, and s is the number of stator modules; the modular stator 1 adopts a true fraction slot concentrated winding, and one sub-module 1-5 is formed from one coil-removed stator slot to the next coil-removed stator slot, and the slot number thereof is Z r =12·(b / 6+c) and Z r =Z / r; wherein Z is the number of stator slots, r is the same as the number of removed coils and the number of sub-modules, b=1, 2, 4, 5 is an integer satisfying the stator block rule, and c=0, 1, 2, 3, … is a natural number.

[0030] The motor adopts rectangular slot and fractional slot concentrated winding structure, each stator module coil 2 is decoupled by removing a small amount of coil 2, and is divided into blocks at part of the blank tooth, and a modular stator 1 structure is formed; from one coil-removed stator slot to the next coil-removed stator slot is a sub-module 1-5, at least one group of coils 2 belonging to A, B and C three phases are removed in each stator module, which is equivalent to an independent small motor, and different module numbers l can be controlled to run according to different load areas. The rotor magnetic pole 3-1 stamping sheet is laminated into blocks, and the magnetic ring 3-3 is combined and installed on the support cylinder 4 through bolts, the magnetic steel groove is formed between the rotor magnetic poles 3-1, and the permanent magnet 3-2 is bonded in the magnetic steel groove through an epoxy resin adhesive to form the rotor 3.

[0031] Compared with the conventional double-layer winding, the coil-removed modular winding structure removes a small amount of coil 2 at the module combination, the remaining winding is arranged in the slot in the same way as the conventional winding, and the motor can still perform normal electromechanical energy conversion. The modular stator 1 structure realizes complete decoupling of the windings between the modules, the three-phase windings are symmetrically distributed between the modules, and each module is equivalent to an independent small rotating motor controlled by a respective frequency converter, thereby forming a modular permanent magnet motor.

[0032] The modular stator 1 structure realizes complete decoupling of the windings between the modules, the three-phase windings are symmetrically distributed between the modules, and each module is equivalent to an independent small rotating motor controlled by a respective frequency converter, thereby enabling different module numbers l to be controlled to run according to different load areas. In order to accurately illustrate the decoupling effect between the modules of the utility model, the back electromotive force waveform under different module numbers and the overall back electromotive force waveform diagram are given, as shown in Figure 4 , the back electromotive force waveforms are basically the same, so the modules are independent of each other.

[0033] In order to further verify that the motor can still run stably under the influence of the radial electromagnetic force when an odd number of modules run asymmetrically, the vibration deformation of the motor under full load operation under different module numbers is given, as shown in Figure 5 , when all the modules run at rated speed, the maximum stator vibration displacement is 1.38x10 -6 m, and the maximum stator vibration displacement under other operating modes is 1.23x10 - 6 m, and the deformation of the entire stator is unevenly distributed. However, compared with the motor air gap 2.2x10 -3 m, the stator vibration displacement values under the four operating modes at rated operating conditions are very small, and the influence of the asymmetric radial electromagnetic force can be ignored. Therefore, the modular permanent magnet motor can run stably in Figure 5 the four operating modes at rated operating conditions.

[0034] To maximize the advantages of the modular permanent magnet motor, four mode efficiency optimization torque distribution control methods based on variable load area division are proposed: low load area P set1 , l = 1, put into a module to run, that is, any one of stator module 1-1, stator module 2-1, stator module 3-1, and stator module 4-1; the second low load area P set2 , l = 2, put into two symmetrical modules to run, that is, any two of stator module 1-1 and stator module 3-1 or stator module 2-1 and stator module 4-1; the second high load area P set3 , l = 3, put into three modules to run, that is, any three of stator module 1-1, stator module 2-1, stator module 3-1, and stator module 4-1; the high load area P set4 , l = 4, all four modules run, that is, stator module 1-1, stator module 2-1, stator module 3-1, and stator module 4-1 all run; to ensure that the motor always works in a high efficiency state under variable load.

[0035] The specific implementation steps of the efficiency optimization torque distribution control are as follows:

[0036] On the basis of considering maximum torque and minimum loss, when the motor output maximum torque is equal to the load torque T set , the optimal solution of the current amplitude I and the maximum torque current angle β is obtained.

[0037]

[0038] The number of modules l put into operation under the efficiency optimization is the determination of the load distribution coefficient.

[0039] l = P set / P (2)

[0040] Where, P set is the system target load; P is the load of a module.

[0041] According to the loss model, the motor electrical loss is

[0042]

[0043] Where, P loss is the motor electrical loss, that is, the sum of iron loss and copper loss; P lossi is the electrical loss when the i-th module is running, i = 1, 2, 3, 4; i dti , i qti is the direct axis component and the quadrature axis component of the torque current of the i-th module; R s is the resistance of a module stator winding; R c is the equivalent iron loss resistance of a module; Ld , L q is the direct-axis and quadrature-axis inductance of one module; ω is the mechanical angular velocity; p is the pole pair number of the motor; ψ f is the permanent magnet flux linkage of one module.

[0044] The motor efficiency is

[0045] η l = (1 - P loss / P set ) x 100% (4)

[0046] According to the mathematical model (1), the motor efficiency η l under different operating modes is obtained.

[0047]

[0048] where P max is the maximum load of one module; n is the motor operating speed; n N is the rated speed.

[0049] Taking the modular permanent magnet motor with a power of 80 kW as an example, the number of modules l and the efficiency distribution under different loads are obtained according to the above calculation, as shown in FIG. 2. According to the results, the system efficiency can be optimized by running corresponding different number of modules according to the demand of the variable load. At this time, the value of l under different load intervals is: Figure 6

[0050]

[0051] The efficiency optimization torque distribution control block diagram is shown in FIG. 3. In this method, each module is powered by its own inverter, and all inverters operate with a common DC bus. An optional module is selected as the master module, and the remaining modules are slave modules. The speed and electrical angle are known, the number of modules to be put into operation is determined according to the target load range, the load demand is converted into torque command input to each module, and then the torque is controlled to realize system efficiency optimization torque distribution control. Figure 7

[0052] The motor efficiency curves under the uniform torque distribution and the efficiency optimization torque distribution control under different loads are compared, as shown in FIG. 4. It can be seen from the comparison that when running in the low load region, the efficiency optimization torque distribution control can greatly improve the motor operating efficiency. Figure 8

[0053] ​​​The above described embodiments are only preferred embodiments of the present application, and are not all the embodiments of the present application which can be implemented. Any obvious changes made by those skilled in the art without departing from the principles and spirit of the present application should be considered to be included in the protection scope of the claims of the present application. Although the present application has been described above with reference to the embodiments, various improvements can be made and equivalent components can be replaced without departing from the scope of the present application. In particular, as long as there is no technical conflict, the features in the disclosed embodiments of the present application can be combined in any manner, and the combinations are not exhaustively described in the specification only for the purpose of saving space and resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A modular permanent magnet electric machine characterized by, It comprises a modular stator (1), a coil (2) and a rotor (3); the modular stator (1) comprises a stator module one (1-1), a stator module two (1-2), a stator module three (1-3) and a stator module four (1-4) connected in series; the coil (2) is embedded and distributed in the stator slot of the modular stator (1), and at least one group of coils (2) belonging to A, B and C three phases is removed in each stator module; the rotor (3) comprises a plurality of rotor magnetic poles (3-1), the magnetic steel slots are formed between the rotor magnetic poles (3-1), the permanent magnets (3-2) are bonded in the magnetic steel slots, the permanent magnets (3-2) are bonded with the magnetic isolation ring (3-3), the rotor magnetic poles (3-1) are fixed on the magnetic isolation ring (3-3) and the support cylinder (4), and the air gap is formed between the modular stator (1) and the rotor (3).

2. The modular permanent magnet electric machine of claim 1, wherein, The permanent magnet (3-2) is bonded in the magnetic steel slot through an epoxy resin adhesive.

3. The modular permanent magnet electric machine of claim 1, wherein, The permanent magnet (3-2) is bonded with the magnetic isolation ring (3-3) through an epoxy resin adhesive.

4. The modular permanent magnet electric machine of claim 1, wherein, Each coil-removed stator module (2) belongs to at least one group of A, B and C three phases, the number of removed coils r=3ks, k=1, 2, 3, …, s is the number of stator modules; the modular stator (1) adopts a true fraction slot concentrated winding, from one coil-removed stator slot to the next coil-removed stator slot is a sub-module (1-5), and the slot number is Z r =12·(b / 6+c) and Z r =Z / r; wherein Z is the number of stator slots, r is the same as the number of removed coils and the number of sub-modules, b=1, 2, 4, 5 is an integer satisfying the stator block rule, and c=0, 1, 2, 3, … is a natural number.

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