CN101621234A - Magnetic flow switching type axial magnetic field magnetoelectric machine with middle stator structure - Google Patents

Abstract

The intermediate stator structure flux switching type axial field permanent magnet motor is a double air gap permanent magnet motor composed of a stator (1) and two rotors (2). The stator (1) and the rotor (2) are coaxially installed, and the stator ( 1) Sandwiched between two rotors (2), there is an air gap of a certain thickness between the rotor (2) and the stator (1), and each stator (1) is composed of 12 "H" shaped stator cores (5), composed of 12 permanent magnets (6) and 12 coils (7), "H" shaped stator cores (5) and permanent magnets (6) are alternately placed to form a disc, the "H" on the stator (1) The stator core (5) and the permanent magnets (6) correspond to each other, but the permanent magnets in the stator are magnetized alternately along the circumferential direction; the permanent magnets and concentrated armature windings are all placed in the stator, and there is no permanent magnet on the rotor There is also no armature winding; the simple rotor structure can effectively improve the reliability of the motor operation; the axial magnetic field structure makes the axial dimension of the motor shorter, so that the motor has a higher power density; the outer rotor structure makes the rotor rotate, Can act as a fan.

Description

Flux-switching axial field permanent magnet motor with intermediate stator structure

technical field

The invention relates to an axial field permanent magnet motor with an intermediate stator structure and flux switching type, which is an improvement to the traditional intermediate stator structure axial field permanent magnet motor and belongs to the technical field of permanent magnet motors.

Background technique

my country is rich in rare earth resources. The reserves of rare earth ores are about four times that of other countries in the world. The output of rare earth ores and rare earth permanent magnets ranks among the top in the world. The scientific research level of rare earth permanent magnet materials and rare earth permanent magnet motors has also reached the international advanced level. Therefore, it has important theoretical significance and engineering practical value to give full play to the advantages of my country's rich rare earth resources and vigorously research and promote the application of various permanent magnet motors represented by rare earth permanent magnet motors.

Compared with traditional electric excitation motors, permanent magnet motors, especially rare earth permanent magnet motors, have significant advantages such as simple structure, reliable operation, small size, light weight, low loss, high efficiency, and flexible shape and size of the motor. Over the past ten years, research hotspots have been focused on rotor permanent magnet motors represented by surface mount, plug-in and embedded. However, placing permanent magnets on the rotor will cause a series of problems during the operation of the motor. For example, for the structure of permanent magnets pasted on the surface of the rotor or inserted between the salient poles of the rotor, in order to overcome the influence of centrifugal force generated by high-speed operation, it is usually necessary to Make auxiliary permanent magnet fixing device, which will make it difficult for the rotor to dissipate heat. Excessive temperature rise will cause irreversible demagnetization of the permanent magnet, which will limit the output of the motor and reduce the output power of the motor; and for the permanent magnet embedded in the rotor core The embedded structure will affect the mechanical strength of the rotor, and an auxiliary magnetic bridge is required, which complicates the manufacturing process. In addition, for rotor permanent magnet motors, the armature reaction flux generated by the stator windings will enter the rotor and couple with the permanent magnets, and there is a certain degree of risk of demagnetization.

If the traditional axial field permanent magnet motor adopts a slotless structure, its magnetic load is small. Although the slotted structure has a high power density, it is difficult to manufacture and requires special equipment. In addition, whether it is a single air gap or double air gap axial field permanent magnet motor, the rotor is made of high-performance permanent magnet materials bonded to solid steel or silicon steel sheets. In this way, during its operation, some of the above-mentioned problems will occur, and the manufacturing cost of the motor will also be increased.

French scholar E. Hoang first proposed a three-phase 12/10 structure permanent magnet flux switching permanent magnet motor at the EPE conference in 1997. The stator is a "U"-shaped iron core, and a tangential alternate magnetization is embedded in the middle. Permanent magnets. Subsequently, universities and research institutes such as Southeast University, Nanjing University of Aeronautics and Astronautics, Leicester University and Sheffield University have done in-depth research on flux-switching permanent magnet motors and achieved a lot of results. The so-called flux switching motor means that with the change of the rotor position, the excitation flux switches its path, so that the magnitude and direction of the flux linkage in the stator winding change, thereby generating an alternating electric potential. The permanent magnet flux switching motor has no excitation loss, the stator and rotor cores are double-salient pole structure, there is neither permanent magnet nor winding on the rotor, the structure is simple, the operation is reliable, the efficiency is high, the cooling is convenient, and it has high power. density and efficiency. Unfortunately, most of the current research on permanent magnet flux switching motors focuses on radial field motors, which are not suitable for occasions that strictly require thin installation. The motor has important significance and use value.

Contents of the invention

Technical problem: Aiming at the deficiencies of traditional axial field permanent magnet motors, in order to improve the performance of axial field permanent magnet motors, the present invention proposes a rotor without permanent magnets and armature windings, with simple structure, high power density and high efficiency. Flux switching type axial field permanent magnet motor with intermediate stator structure.

Technical solution: The intermediate stator structure magnetic flux switching type axial field permanent magnet motor of the present invention is a double air gap permanent magnet motor composed of a stator and two rotors, the stator and the rotor are installed coaxially, and the stator is sandwiched between the two rotors There is an air gap between the rotor and the stator; the structure of the two rotors is exactly the same, and they are symmetrical about the stator; the stator unit composed of 6 H-shaped stator cores and 6 permanent magnets is combined with 5 rotor poles The rotor unit constitutes a "basic motor", and the stator unit and rotor poles of the basic motor are expanded by integer multiples to obtain a motor with a 6a/5a structure, where a is a positive integer. Each stator includes 6a H-shaped stator cores, 6a permanent magnets and 6a concentrated winding coils. The H-shaped stator cores and permanent magnets are placed alternately to form a disc, and each coil straddles the teeth of two H-shaped stator cores. , with permanent magnets embedded in the middle, and the permanent magnets are alternately magnetized along the circumferential direction. The 6a concentrated winding coils are divided into three phases, in which 2a coils separated by two slots are connected in series to form one phase, that is, the A, B, and C three-phase windings are connected in series in pairs at an electrical angle of 120°; the same-phase windings on both sides of the stator are connected in series or in parallel.

The rotor has a total of 5a teeth, called 5a rotor poles, which are uniformly arranged on the disc surface of the rotor yoke, and are opposite to the teeth of the stator on this rotor side. The teeth of the H-shaped stator core and the rotor poles are all parallel teeth, or both are sector teeth.

Beneficial effects: the intermediate stator structure flux switching type axial field permanent magnet motor proposed by the present invention reasonably applies the concept of flux switching to the axial field permanent magnet motor, and concentrates the traditional axial field permanent magnet motor and flux Advantages of switched permanent magnet motors. The rotor has a simple structure and short axial dimension, which solves a series of problems caused by the placement of permanent magnets in the rotor.

The stator adopts an "H" shaped magnetic core, which is easier to manufacture than the traditional axial magnetic field permanent magnet motor.

Since the permanent magnets are arranged between two adjacent stator teeth of the stator, when the rotor poles are aligned with different stator teeth, the directions of the permanent magnetic fluxes generated by the permanent magnets passing through the coils will be different, resulting in flux switching Effect, causing the permanent magnetic flux linkage of the turn chain in the coil to be bipolar.

Since the first winding coil (A1 in Figure 1) and the third winding coil (A3 in Figure 1) of any one phase of the concentrated winding are diametrically opposite, the second winding coil (A2 in Figure 1) and the third winding coil (A2 in Figure 1) The four-winding coils (A4 in Figure 1) are diametrically opposed, so at four fixed rotor positions (respectively corresponding to the positive maximum, negative maximum and two zero-crossing points of the permanent magnet flux linkage of the turn chain), a The number and direction of the permanent magnet flux linkages of the turn chains in the two sets of coil windings (A1 and A3, A2 and A4) of the phase are the same. On the other hand, since there is a 180-degree phase difference on the magnetic circuit between two sets of concentrated winding coils forming one phase (each set consists of two radially opposite coils in series), the coils can be used in the magnetic field when they are connected in series. The circuit has complementary characteristics, so that the high-order harmonic components in the one-phase permanent magnet flux linkage of the turn-link winding and the no-load electromotive force waveform generated by induction are equal in amplitude and complementary in phase, and when synthesized into one-phase flux linkage or electric potential , Automatically offset most of the harmonics, so that the total harmonic distortion rate of flux linkage or electric potential is significantly reduced, and its total harmonic distortion rate is less than 2%.

The structural characteristics of the motor make it have a magnetic concentration effect, a large no-load air gap flux density, a strong torque output capability, and a high power density; at the same time, the resistance is small and the efficiency is high. Moreover, the armature reaction flux and the permanent magnet flux are connected in parallel on the magnetic circuit, which ensures that the permanent magnet excitation of the motor has strong anti-demagnetization ability.

In addition, compared with the flux-switching axial field permanent magnet brushless motor with intermediate rotor structure (Chinese invention patent, application number: 200810019783.2), this motor has the following characteristics:

1) The structure is different. The motor has a double-rotor, single-stator structure, the stator core is "H"-shaped, the rotor pole and the rotor yoke disc are integrated; and the flux-switching axial magnetic field permanent magnet brushless motor (Chinese invention patent, Application number: 200810019783.2) is a single-rotor, double-stator structure, the stator core is U-shaped, and the rotor poles are evenly arranged on the non-magnetic ring, which is a non-integrated structure.

2) Better heat dissipation performance. The double rotors are placed on both sides of the motor, and the stator is placed in the middle. When the motor is running stably, the rotors play the role of a fan; in addition, due to the difference in the structure of the rotors, the effective heat dissipation space between the stators and rotors of this motor is significantly larger than that of the magnetic flux switching type. Magnetic field permanent magnet brushless motor (Chinese invention patent, application number: 200810019783.2), which also makes its heat dissipation effect better.

3) The utilization rate of the permanent magnet is high. The rotors on both sides of the motor are symmetrical with respect to the stator, so the magnetic field in the motor is also distributed symmetrically. The air gap, the stator teeth on both sides and the stator yoke on both sides are symmetrically dropped, and the magnetic circuit is closed along the path shown in Figure 3; while the magnetic flux switching axial field permanent magnet brushless motor (Chinese invention patent, application number: 200810019783.2) , two permanent magnets that are symmetrical about the rotor are connected in series, and act together on the air gaps on both sides of the rotor and the corresponding magnetic circuit. In view of this, the permanent magnet utilization rate of the motor is higher than that of the flux switching axial field permanent magnet brushless motor (Chinese invention patent, application number: 200810019783.2).

4) The moment of inertia is large. In the case of the same rated power, since the motor has dual rotors, the mass of the rotor is relatively large, so its moment of inertia is greater than that of the flux-switching axial field permanent magnet brushless motor (Chinese invention patent, application number: 200810019783.2). In this way, when the motor is used as a wind power generator, its advantages are particularly obvious.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of a flux switching type axial field permanent magnet motor with a 12/10 structure intermediate stator structure;

Fig. 2 is the plane expansion diagram of the magnetic flux switching type axial field permanent magnet motor with the intermediate stator structure;

Above figure has: stator 1, rotor 2, rotor pole 3, rotor yoke 4, H-shaped stator core 5, permanent magnet 6, concentrated winding coil 7.

A1, A2, A3, and A4 are four concentrated winding coils whose radial centerlines are perpendicular to each other;

Fig. 3 is a schematic diagram of a magnetic circuit of an axial field permanent magnet motor with a magnetic flux switching type with an intermediate stator structure.

Detailed ways

The intermediate stator structure magnetic flux switching axial field permanent magnet motor proposed by the present invention is a double air gap permanent magnet motor composed of a stator and two rotors. The stator and the rotor are installed coaxially, and the stator is clamped between the two rotors. There is an air gap between the rotor and stator. The structure of the two rotors is exactly the same, and they are symmetrical about the stator. The stator consists of 6a H-shaped magnetic cores, 6a permanent magnets and 6a concentrated windings composed of coils. H-shaped stator cores and permanent magnets are placed alternately to form a disk, and the two adjacent permanent magnets in the stator are magnetized in opposite directions. The 2a coils on each side of the stator are divided into three phases, and the four coils whose radial center lines are perpendicular to each other (such as the four coils A1, A2, A3 and A4 in Figure 1) are connected in series to form a one-phase winding. The windings on both sides of the stator Phase parallel or series. Each coil is wound on the teeth of two "H"-shaped stator cores, and permanent magnets are embedded in the middle, and the permanent magnets are alternately magnetized along the circumferential direction. The rotor has a total of 5a teeth (poles), which are evenly arranged on the disc surface of the rotor yoke and are opposite to the stator teeth. The teeth of the H-shaped stator core and the rotor poles are all parallel teeth, or both are sector teeth. The motor is obtained by expanding the "basic motor" composed of 6 H-shaped stator cores, 6 permanent magnets, and the "basic motor" composed of a stator unit and 5 rotor poles. If the basic motor is expanded by integer multiples, 6a/5a can be obtained structure of the motor, where a is a positive integer.

As shown in Figure 1, the 12/10 structure intermediate stator structure flux switching type axial field permanent magnet motor is a double air gap permanent magnet motor composed of a stator 1 and two rotors 2, and the stator 1 and the rotor 2 are installed coaxially , the stator 1 is sandwiched between two rotors 2, and there is an air gap of a certain thickness between the rotor 2 and the stator 1. The structures of the two rotors 2 are exactly the same, and they are symmetrical about the stator 1; each stator 1 is composed of 12 "H" shaped stator cores 5, 12 permanent magnets 6 and 12 concentrated winding coils 7, "H" shaped Stator cores 5 and permanent magnets 6 are alternately placed to form discs, and the magnetization directions of two adjacent permanent magnets are opposite; 12 concentrated winding coils 7 are divided into three phases, and every four coils are connected in series to form a phase winding, and the windings on both sides of the stator Phase parallel or series connection is adopted; each coil straddles the teeth of two "H" shaped stator cores 5, and permanent magnets 6 are embedded in the middle, and the permanent magnets 6 are alternately magnetized along the circumferential direction. The rotor 2 has 10 teeth in total, called 10 rotor poles 3, which are evenly arranged on the disk surface of the yoke of the rotor 2, and are opposite to the teeth of the stator on the rotor side. The H-shaped stator core 5 is formed by punching silicon steel sheets, and the rotor 2 is also formed by stacking silicon steel sheets with high magnetic permeability. The rotor 2 is simple in structure, and has neither permanent magnets nor armature windings on it.

When the prime mover drives the rotor to rotate, the relative position between the rotor poles and the stator teeth changes. As shown in Figure 2, when the relative position of the stator and rotor changes, the excitation flux switches its path, so that the permanent magnet flux linked by each armature winding alternates, and the direction of the flux changes from entering the rotor from the stator to from the rotor Entering the stator, the value changes periodically between a maximum value and a minimum value. According to Faraday's law of electromagnetic induction, an induced electromotive force with alternating amplitude and phase will be generated in the conductors at both ends of each armature winding. When the armature winding is connected to the load, an AC current can be output to realize the generator operation of the motor.

The permanent magnet motor of the present invention can also be operated as an electric motor. As shown in Figure 2, the rotor poles on both sides are facing each other. When a certain pole of the rotor is facing the stator teeth, the current direction of the left conductor of the coil facing the rotor pole on the rotor is perpendicular to the inside of the paper, and the other conductor of the coil is (Right conductor) The current direction is perpendicular to the paper surface outward, and the current direction in the left and right conductors of the coil under the stator opposite to this coil is opposite to it, that is, the current direction of the left conductor is perpendicular to the paper surface outward, and the current direction of the right conductor The direction is perpendicular to the paper face inward. In this way, the combined magnetic flux of the left half of the permanent magnet flux and the armature magnetic flux of the rotor poles on both sides is mutually strengthened, and the combined magnetic flux of the right half is mutually weakened, and the rotor poles on both sides are subjected to horizontal For the force to the left, the other rotor poles are subjected to the same force analysis as above, and they are all subjected to the force to the left, so that the rotor moves to the left. Obviously, if you change the direction of the current at this moment, the rotor will move to the right.

Claims (3)

1. intermediate stator structure magnetic flow switching type axial magnetic field magnetoelectric machine, it is characterized in that two air gap permanent magnet motors that this motor is made of a stator (1) and two rotors (2), stator (1) and the coaxial installation of rotor (2), stator (1) folds up between two rotors (2), leaves air-gap between rotor (2) and the stator (1); The structure of two rotors (2) is just the same, and about stator (1) symmetry; Constitute " basic motor " by 6 H shapes stator core (5) and 6 permanent magnets (6) stator unit of forming and the rotor unit that is combined into by 5 rotor poles, the stator unit and the rotor pole of basic motor are carried out the integral multiple expansion, obtain the motor of 6a/5a structure, wherein a is a positive integer.Each stator (1) comprises 6a H shape stator core (5), 6a piece permanent magnet (6) and 6a concentrated winding coil (7), H shape stator core (5) and permanent magnet (6) are alternately placed and are constituted disk, each coil is across on the tooth of two H shapes stator core (5), the middle permanent magnet (6) that embeds, permanent magnet (6) alternately magnetizes along circumferencial direction.6a concentrated winding coil is divided into three-phase, and 2a coil of two grooves of wherein whenever being separated by is connected into a phase, and promptly A, B, the C three phase windings 120 ° of electrical degrees of being separated by in twos are in series; The relative same phase winding in stator both sides is in series or is in parallel.

2. intermediate stator structure magnetic flow switching type axial magnetic field magnetoelectric machine according to claim 1, it is characterized in that rotor (2) has 6a tooth, be called 5a rotor pole (3), evenly be arranged on the disc surfaces of rotor yoke, and relative with stator at the tooth of this rotor-side.

3. intermediate stator structure magnetic flow switching type axial magnetic field magnetoelectric machine according to claim 1 is characterized in that the tooth of H shape stator core (5) and rotor pole (3) all are parallel teeth, or all is sector.

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