阅读说明：本技术 一种分数极两相游标永磁直线电机 (Fractional-pole two-phase vernier permanent magnet linear motor ) 是由 李大伟 李睿 曲荣海 石超杰 周游 于 2019-11-11 设计创作，主要内容包括：本发明公开了一种分数极两相游标永磁直线电机,包括：电枢绕组、初级铁心轭部、初级铁心齿部、永磁磁极和次级铁心；永磁磁极阵列均匀分布在次级铁心上,且相邻永磁磁极极性相反；电枢绕组、初级铁心轭部和初级铁心齿部组成电机初级；永磁磁极和次级铁心组成电机次级；直线电机初级与次级之间存在气隙,两者可以相互移动。本发明取消了传统游标永磁直线电机中有效永磁磁极数为偶数的约束,提出了分数极概念,使永磁直线电机有效磁极数可以为分数,扩充了可能的极槽配合方案,提高了直线电机设计自由度。本发明在保持游标永磁直线电机的高推力密度特性的同时,降低了水平推力波动和纵向磁拉力波动,有助于提高电机的控制精度和响应速度。(The invention discloses a fractional pole two-phase vernier permanent magnet linear motor, which comprises: the permanent magnet motor comprises an armature winding, a primary iron core yoke part, a primary iron core tooth part, a permanent magnet magnetic pole and a secondary iron core; the permanent magnetic pole arrays are uniformly distributed on the secondary iron core, and the polarities of the adjacent permanent magnetic poles are opposite; the armature winding, the primary iron core yoke part and the primary iron core tooth part form a primary motor; the permanent magnetic pole and the secondary iron core form a secondary of the motor; an air gap exists between the primary and the secondary of the linear motor, and the primary and the secondary can move mutually. The invention cancels the constraint that the number of the effective permanent magnet poles in the traditional vernier permanent magnet linear motor is even, provides a fractional pole concept, ensures that the number of the effective permanent magnet poles of the permanent magnet linear motor can be fractional, expands the possible pole slot matching scheme and improves the design freedom of the linear motor. The invention reduces the horizontal thrust fluctuation and the longitudinal magnetic tension fluctuation while keeping the high thrust density characteristic of the vernier permanent magnet linear motor, and is beneficial to improving the control precision and the response speed of the motor.)

1. The utility model provides a fraction pole two-phase vernier permanent magnet linear motor which characterized in that includes: the permanent magnet motor comprises an armature winding (1), a primary iron core yoke part (2), a primary iron core tooth part (3), a permanent magnet magnetic pole (4) and a secondary iron core (5);

the armature winding (1) surrounds the primary core tooth (3); the primary iron core yoke part (2) and the primary iron core tooth part (3) form a primary iron core of the motor; the permanent magnet poles (4) with the same size are uniformly distributed on the secondary iron core (5) along the primary motion direction of the motor to form a permanent magnet array, and the polarities of the adjacent permanent magnet poles are opposite.

2. The fractional pole two phase vernier permanent magnet linear motor of claim 1 wherein the linear motor primary corresponds to an effective permanent magnet pole count of 2P_fIs not an integer; an air gap exists between the motor primary and the motor secondary and the air gap can move mutually.

3. The fractional pole two phase vernier permanent magnet linear motor of claim 2 wherein the motor effective permanent magnet pole number is 2P_fPrimary core slot number Z_sNumber of pole pairs P with armature winding_aThe magnetic field modulation principle is satisfied: p_a＝|P_f±Z_s|。

4. The fractional pole two phase vernier permanent magnet linear motor as claimed in any one of claims 1 to 3 wherein the armature winding pole pair number P of the vernier permanent magnet linear motor_aPrimary core slot number Z_sAnd the phase number m of the winding satisfies the relation:

wherein k is an arbitrary integer and Q is such that P_aQ is the smallest integer of the integers and GCD is the greatest common divisor operation.

5. The fractional pole two phase vernier permanent magnet linear motor of any one of claims 1 to 4 wherein the pole slot matching of the motor is determined from a slot number radial plot.

6. The fractional pole two phase vernier permanent magnet linear motor of claim 5 wherein the fundamental order of the electromagnetic ripple with respect to the fundamental electrical frequency

Wherein LCM is the least common multiple operation, 2P_fNumber of permanent magnet poles, Z_sIs the number of slots of the primary core of the motor, P_aIs the number of pole pairs of the armature winding, Q is such that P_aQ is the smallest positive integer of the integers.

Technical Field

The invention belongs to the technical field of permanent magnet motors, and particularly relates to a fractional-pole two-phase vernier permanent magnet linear motor.

Background

Compared with a scheme that the linear motion is formed by a rotating motor and a ball screw, the scheme that the linear motion is directly generated by the linear motor has a simpler structure, higher efficiency and better stability. Therefore, linear motors are increasingly favored in industrial fields requiring linear motion. The linear motor is classified into a linear induction motor and a linear permanent magnet motor. Compared with a linear induction motor, the linear permanent magnet motor has better thrust density, power factor and efficiency performance. Among numerous linear motor topologies, the vernier permanent magnet linear motor adopting the principle of the permanent magnet and the vernier motor has the characteristics of simple structure and high efficiency of the permanent magnet motor and the characteristics of low speed and high torque of the vernier motor, so that the vernier permanent magnet linear motor attracts attention in recent years.

As shown in fig. 1, the pole-slot mating of a linear motor is typically designed from an equivalent rotating electrical machine. In a rotating electrical machine, since the mechanical positions of 0 electrical degrees and 360 electrical degrees coincide, the number of permanent magnet poles of the machine must be even, so that the electrical angle of the machine varies periodically around the circumference of the machine. Since linear motors come from equivalent rotating machines, the same constraint (i.e., an even number of motor permanent magnet poles) is often followed in the design of linear motors, which is actually a redundant constraint. Meanwhile, the problem that the end part of the motor is very long also exists in the pole slot matching design of integral poles of the traditional vernier permanent magnet linear motor. In the linear motor, the mechanical positions of 0 electrical angle and 360 electrical angle are not coincident, so that the permanent magnet poles in the effective length of the rotor can be selected as fractions. Without the constraint of the number of dipoles, the linear permanent magnet motor has more new pole slot matching choices.

When the linear permanent magnet vernier motor operates, longitudinal magnetic tension is generated between the permanent magnet magnetic pole and the primary side of the linear motor; meanwhile, due to the influence of the inherent edge-end effect of the traditional permanent magnet linear motor, the electromagnetic thrust and the longitudinal magnetic tension in the operation process of the permanent magnet linear motor have large fluctuation. The fluctuating longitudinal magnetic pull force not only can increase the deformation risk of a motor guide rail and a system supporting component, but also introduces a variable resistance to the system, increases the control difficulty of the motor, and reduces the control precision and response speed of the system.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a fractional-pole two-phase vernier permanent magnet linear motor, which aims to cancel the constraint that the number of poles in the effective range of the vernier permanent magnet linear motor is even and increase the design freedom of the vernier permanent magnet linear motor.

The invention provides a fractional pole two-phase vernier permanent magnet linear motor, which comprises: an armature winding, a primary core yoke, a primary core tooth, a permanent magnet pole and a secondary core; the armature winding surrounds the primary iron core tooth part; the primary iron core yoke part and the primary iron core tooth part form a primary iron core of the motor; and a plurality of permanent magnet poles with the same size are uniformly distributed on the secondary iron core along the primary motion direction of the motor to form a permanent magnet array, and the polarities of the adjacent permanent magnet poles are opposite.

Furthermore, the primary of the linear motor corresponds to the effective permanent magnet pole number 2P_fIs not an integer; an air gap exists between the motor primary and the motor secondary and the air gap can move mutually.

Further, the effective permanent magnet pole number of the motor is 2P_fPrimary core slot number Z_sNumber of pole pairs P with armature winding_aThe magnetic field modulation principle is satisfied: p_a＝|P_f±Z_s|。

Furthermore, the armature winding pole pair number P of the vernier permanent magnet linear motor_aPrimary core slot number Z_sAnd the phase number m of the winding satisfies the relation:

wherein k is an arbitrary integer and Q is such that P_aQ is the smallest integer of the integers and GCD is the greatest common divisor operation.

Further, the pole-slot fit of the motor is determined according to the slot number star map.

Further, the order of the fundamental wave of the electromagnetic force fluctuation with respect to the electrical frequency of the fundamental wave

Wherein LCM is the least common multiple operation, 2P_fNumber of permanent magnet poles, Z_sIs the number of slots of the primary core of the motor, P_aIs the number of pole pairs of the armature winding, Q is such that P_aQ is the smallest positive integer of the integers.

Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) the motor structure provided by the invention cancels the limitation that the number of the magnetic poles in the primary effective range of the linear motor is even, introduces the concept of fractional poles, enables the number of the permanent magnet poles in the effective length of the rotor of the permanent magnet linear motor to be selected as fractional numbers, enables more pole slots of the permanent magnet linear motor to be matched and selected, and increases the design freedom degree of the permanent magnet linear motor.

(2) The motor structure provided by the invention can effectively reduce the electromagnetic thrust fluctuation and the longitudinal magnetic tension fluctuation of the motor, reduce the disturbance of the linear motor in the operation, reduce the control difficulty of the motor, improve the control precision and the operation efficiency of the linear motor and shorten the response time of a system.

(3) In the motor structure provided by the invention, the size of the iron core teeth close to the end part can be properly adjusted, a new design freedom degree is introduced, and the optimization of the linear motor on thrust fluctuation is facilitated.

(4) The invention provides a novel pole slot matching, which can effectively shorten the end length of the motor, improve the motor efficiency and power factor, reduce the motor manufacturing cost, make a linear motor system more compact and improve the motor output density.

Drawings

FIG. 1 is a schematic diagram of a linear motor designed from an equivalent rotating electrical machine;

fig. 2 is a schematic cross-sectional structure view of a fractional pole vernier permanent magnet linear motor and its winding arrangement according to the present invention;

fig. 3 is a no-load magnetic field distribution of the fractional pole vernier permanent magnet linear motor provided by the invention;

fig. 4 is a slot potential star diagram of the fractional pole vernier permanent magnet linear motor and its winding phase splitting according to the present invention;

FIG. 5 is a schematic diagram of an unloaded back emf waveform of the armature winding;

FIG. 6 is a schematic illustration of the harmonic content distribution of the no-load back emf waveform of the armature winding;

fig. 7 shows the average electromagnetic thrust of the two-segment fractional pole vernier permanent magnet linear motor under different load conditions;

fig. 8 shows longitudinal magnetic tension waveforms of the two-segment fractional pole vernier permanent magnet linear motor under different load conditions.

Wherein: 1 is an armature winding, 2 is a primary iron core yoke, 3 is a primary iron core tooth, 4 is a permanent magnet magnetic pole, and 5 is a secondary iron core.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention introduces a fractional pole concept and provides a fractional pole two-phase vernier permanent magnet linear motor, which comprises: an armature winding, a primary core yoke, a primary core tooth, a permanent magnet pole and a secondary core;

the armature winding surrounds the iron core slots between the primary iron core teeth; the permanent magnetic poles are uniformly distributed on the secondary iron core to form a permanent magnet array, and the polarities of the adjacent permanent magnetic poles are opposite;

the armature winding, the primary iron core tooth part and the primary iron core yoke part jointly form a primary of the vernier permanent magnet linear motor; the permanent magnet array and the secondary back iron form the secondary of the vernier permanent magnet linear motor; an air gap exists between the primary and the secondary of the vernier permanent magnet linear motor, so that the vernier permanent magnet linear motor and the secondary can move mutually; the number of the permanent magnet magnetic poles of the corresponding secondary stage in the primary effective range of the vernier permanent magnet linear motor is a fraction;

irrespective of the end effect, the electromotive forces induced in each primary core slot are equal in magnitude, identical in waveform, but different in phase in time. In the design process of the motor, the pole-slot coordination of the motor is often designed by using a slot number star diagram as shown in fig. 4. The number of each vector in the slot number star diagram is the same as that of the corresponding core slot, and a mark is arranged before the number, which indicates that the conductors in the core slot are in reverse series connection, and the corresponding slot electromotive force vector is also in reverse direction, namely in forward series connection. The vector length represents the amplitude of the fundamental component of the induced electromotive force in the slot, and the included angle between the vectors is the phase difference (electrical angle) between the induced electromotive forces in the iron core slot. After reversing part of the slot potential vectors, the slot number star diagram of the fractional pole two-phase vernier permanent magnet motor of the present invention can be symmetrically divided into A, B two phase bands, corresponding to A, B two phases in the armature winding, as shown in fig. 4.

In a traditional vernier permanent magnet linear motor, the principle of distribution of each phase winding meets the following principle:

wherein Z_sNumber of primary core slots, P_aThe number of the armature winding poles is shown, GCD is the operation of taking the greatest common divisor, m is the number of the armature winding phases, and k is any integer.

After introducing the concept of fractional magnetic pole, the number of armature winding poles P_aInstead of being an integer, the winding assignment relationship should be changed as follows:

wherein Q is such that P_aQ is the smallest positive integer of the integers, and particularly, for the conventional vernier permanent magnet linear motor, Q is 1, so that the conventional vernier permanent magnet linear motor can be regarded as a special case of the present invention.

Further, the number of the permanent magnetic poles is 2P_fThe number Z of primary iron core slots of the motor_sNumber of pole pairs P with armature winding_aThe magnetic field modulation principle is satisfied: p_a＝|P_f±Z_s|。

In introducing a fraction probabilityAfter the idea, the degree of freedom of the motor design is improved, P_aThe range of values that can be taken is extended, and the extended possible slot fits and winding pole pairs are as follows:

where Nc is the order of the fundamental wave of electromagnetic fluctuation relative to the electrical frequency of the fundamental wave, in the conventional vernier permanent magnet linear motor, the parameter can be calculated by the following formula:

after introducing the fractional pole concept, the calculation mode of the major harmonic number should be rewritten as follows:

wherein LCM is the least common multiple operation.

Electromagnetic thrust F borne by primary stage of permanent magnet linear motor_xAnd longitudinal magnetic pull force F_yCan be expressed as:

wherein F_xi，F_yiThe amplitudes of i-th harmonic waves of the electromagnetic thrust and the longitudinal magnetic tension are respectively, and tau is the polar distance of the permanent magnetic poles.

After the formula is rewritten, in the design of pole slot matching of the fractional pole vernier permanent magnet linear motor, N_cCan obtain larger value than the traditional vernier permanent magnet linear motor. Because the harmonic amplitude of the electromagnetic thrust and the longitudinal magnetic pull is in inverse proportion to the number of the harmonic, the fluctuation of the electromagnetic thrust and the longitudinal magnetic pull of the fractional pole vernier permanent magnet linear motor is larger than that of the traditional vernier permanent magnet linear motorThe improvement is obvious.

The fractional pole two-phase vernier permanent magnet linear motor adopts double-layer short-distance windings, but only one layer of windings is arranged in two iron core slots at the primary side end of the motor, so that the size of iron core teeth close to the primary end part in the linear motor can be properly adjusted, and the thrust fluctuation optimization of the linear motor is facilitated.

The proposed two-phase motor is also beneficial to eliminating the problem of asymmetry of the three-phase winding of the traditional three-phase linear motor caused by the end effect. Because the magnetic circuits at two ends of the linear motor are disconnected, the magnetic circuit parameters of the linear motor are different from those of the middle part of the linear motor, and the three-phase motor is provided with three-phase windings, and at most only two-phase windings can be placed at two end parts of the linear motor, so that the problems of three-phase back electromotive force and asymmetric inductance are caused, and the thrust fluctuation during loading is further caused. The two-phase motor can just equally distribute the two end parts to the two-phase windings to achieve the effect of two-phase symmetry, thereby inhibiting the thrust fluctuation under load. In conclusion, the odd-pole two-phase vernier permanent magnet linear motor has natural low no-load positioning force fluctuation, and meanwhile, the two-phase symmetrical design is realized, so that the force fluctuation under the load of the motor is small, and the odd-pole two-phase vernier permanent magnet linear motor has great advantages.

In the embodiment of the invention, with the introduction of the odd pole concept, the end length of the motor can be effectively shortened, the copper loss and the magnetic leakage of the winding of the electrode are reduced, the operation efficiency and the power factor of the motor are improved, and the manufacturing cost of the motor can be reduced. The shorter end portion also enables the linear motor system to be more compact, and improves the thrust density of the linear motor.

As an embodiment of the invention, the primary iron core of the motor is a rotor iron core, and the pole iron core is a stator iron core.

As another embodiment of the present invention, the motor primary core is a stator core, and the pole core is a mover core.

Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:

the motor structure provided by the invention cancels the limitation that the number of the magnetic poles in the primary effective range of the linear motor is even, introduces the concept of fractional poles, enables the number of the permanent magnet poles in the effective length of the rotor of the permanent magnet linear motor to be selected as fractional numbers, enables more pole slots of the permanent magnet linear motor to be matched and selected, and increases the design freedom degree of the permanent magnet linear motor.

The motor structure provided by the invention can effectively reduce the electromagnetic thrust fluctuation and the longitudinal magnetic tension fluctuation of the motor, reduce the disturbance of the linear motor in the operation, reduce the control difficulty of the motor, improve the control precision and the operation efficiency of the linear motor and shorten the response time of a system.

In the motor structure provided by the invention, the size of the iron core teeth close to the end part can be properly adjusted, a new design freedom degree is introduced, and the optimization of the linear motor on thrust fluctuation is facilitated.

The invention provides a novel pole slot matching, which can effectively shorten the end length of the motor, improve the motor efficiency and power factor, reduce the motor manufacturing cost, make a linear motor system more compact and improve the motor output density.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 2, an embodiment of the present invention provides a fractional pole vernier permanent magnet linear motor, and sets a pole-slot coordination through a slot potential diagram, including: an armature winding 1, a primary iron core yoke 2, primary iron core teeth 3, a permanent magnet pole 4 and a secondary iron core 5; the armature winding 1 surrounds the primary iron core teeth 3; the primary iron core yoke part 2 and the primary iron core teeth 3 form a primary iron core of the motor; a plurality of permanent magnet poles 4 with the same size are uniformly distributed on the secondary iron core 5 to form a permanent magnet array, and the polarities of the adjacent permanent magnet poles are opposite; the armature winding 1, the primary iron core yoke 2 and the primary iron core teeth 3 jointly form a primary of the linear motor; the permanent magnet pole 4 and the pole core 5 jointly form a motor secondary. An air gap exists between the primary and the secondary of the motor, so that the primary and the secondary can move mutually.

The tooth part in the invention canThe magnetic field modulation block is regarded as a modulation block of a permanent magnetic pole, and the function of magnetic field modulation is realized. Effective permanent magnet pole number 2P corresponding to primary iron core of motor_fThe number Z of primary iron core slots of the motor_sNumber of pole pairs P with armature winding_aThe magnetic field modulation principle is satisfied, namely: p_a＝|Z_s±P_fL. In the fractional pole vernier permanent magnet linear motor shown in fig. 2, the number Z of primary iron core slots of the motor _s12, the number of effective permanent magnet poles corresponding to the primary is 2P_f19.5, according to the principle of the vernier permanent magnet linear motor, the number of pole pairs of the armature winding generated after the permanent magnet field is modulated by the split teeth is known to be P_aThe i 9.75-12 i 2.25 is coupled with an armature winding, the distribution of the modulated magnetic field is shown in fig. 3, and the slot vector diagram and the winding arrangement of the 12-slot 19.5-pole fractional pole vernier permanent magnet linear motor are shown in fig. 4.

The fractional pole vernier permanent magnet linear motor is a two-phase motor, and the back electromotive force of a winding and the harmonic analysis thereof are respectively shown in fig. 5 and 6. The electromagnetic thrust of the fractional pole vernier permanent magnet linear motor has large secondary fluctuation and can be eliminated by adopting a two-section structure. The horizontal electromagnetic thrust and longitudinal magnetic tension waveforms of the two-segment fractional pole vernier permanent magnet linear motor under different load conditions are respectively shown in fig. 7 and 8.

The primary iron core of the motor can be a rotor iron core, and correspondingly, the secondary iron core is a stator iron core; the primary iron core of the motor can also be a stator iron core, and correspondingly, the secondary iron core is a rotor iron core.

Number of slots Z of motor in the invention_sIs the equivalent slot number, i.e. the number of slot vectors in the slot potential star diagram.

The motor provided by the invention can be applied to occasions needing linear motion with high thrust or high dynamic response, such as but not limited to transmission systems, servo systems, oil pumping units, electromagnetic ejection devices, plotters, elevators, wave power generation systems and the like.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.