A permanent magnet axial flux motor

Abstract

The present invention relates to a permanent magnet axial flux motor, wherein the rotor comprises a rotor back iron and a magnetic steel arranged on the rotor back iron, and the stator comprises a stator body and a stator winding arranged on the stator body; the stator body comprises an annular stator core matrix and a stator core insert arranged on the end face of the annular stator core matrix, the annular stator core matrix is ​​formed by nesting an oriented silicon steel core and a non-oriented silicon steel core, and the stator core insert is a non-oriented silicon steel core. When in use, by changing the structure of the stator core, the magnetic lines of force generated by the oriented silicon steel core of the stator teeth are prevented from entering the oriented silicon steel core part of the stator yoke, thereby reducing the magnetic leakage of the teeth, reducing the magnetic flux pulsation in the air gap, and improving the motor performance.

Description

Technical Field

[0001] The invention relates to the technical field of flux motors, in particular to a permanent magnet axial flux motor. Background Art

[0002] The disc-type permanent magnet motor has short axial dimensions, light weight, small size and compact structure. In addition, the rotor has a small moment of inertia, a small electromechanical time constant, a high peak torque, and stable low-speed operation. It can be used in small and medium-sized wind power generation fields to achieve breeze starting and has great development potential.

[0003] Due to the existence of the stator core, the traditional motor will have shortcomings such as stator-rotor electromagnetic attraction, core loss and cogging torque during the operation of the motor. At the same time, the existing permanent magnet synchronous motor has leakage magnetic field, the utilization rate of the magnetic steel is not high, and the air gap magnetic density is low, which in turn affects the motor torque density, efficiency and other electrical performance parameters; in specific use, the motor teeth will vibrate and deform in different modes, which affects the life of the motor and increases the noise of the motor.

[0004] The processing of disc motors is complex, especially for oriented silicon steel used in disc motors. The manufacturing of disc motors spliced ​​with multiple materials mixed with oriented and non-oriented materials is complex, and the performance is difficult to guarantee. Summary of the invention

[0005] The object of the present invention is to provide an improved permanent magnet axial flux motor, which can improve the air gap flux density of the axial flux motor and reduce the leakage flux coefficient by improving the stator structure.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is: a permanent magnet axial flux motor, comprising a casing, and a stator and a rotor arranged in the casing, the rotor being arranged on a rotating shaft, characterized in that: the rotor comprises a rotor back iron and a magnetic steel arranged on the rotor back iron, the stator comprises a stator body and a stator winding arranged on the stator body; the stator body comprises an annular stator core matrix and a stator core insert arranged on the end surface of the annular stator core matrix, the annular stator core matrix is ​​formed by nesting an oriented silicon steel core and a non-oriented silicon steel core, and the stator core insert is a non-oriented silicon steel core.

[0007] Preferably, the annular stator core matrix includes a group of annular oriented silicon steel cores symmetrically arranged upper and lower and an annular non-oriented silicon steel core arranged between the upper and lower annular oriented silicon steel cores; the annular oriented silicon steel core is provided with stator slots, which divide the annular oriented silicon steel core into stator teeth, and the bottom of the stator slots together with the annular non-oriented silicon steel core form a stator yoke, and the bottom of the stator slots is provided with through holes to prevent the magnetic lines of force generated by the oriented silicon steel core of the stator teeth from entering the oriented silicon steel core part of the stator yoke.

[0008] Furthermore, a large dovetail groove is provided on the surface of the annular non-oriented silicon steel core, a small dovetail groove is provided below the through hole, and the large and small dovetail grooves are combined to form an I-shaped groove, and a stator core insert is provided in the I-shaped groove, and the stator core insert is an I-shaped non-oriented silicon steel core. The through hole is a plurality of parallel square grooves, the total length of the through hole is less than the bottom width of the stator slot, and the stator slot is a flat bottom slot.

[0009] Furthermore, two symmetrically arranged left and right rotors are provided, the stator is arranged between the two rotors, and the N-pole magnetic steel and the S-pole magnetic steel are alternately arranged on the rotor back iron, so that the magnetic steel polarities of the left and right rotors are the same.

[0010] Furthermore, the I-shaped non-oriented silicon steel core is spliced ​​together by upper, middle and lower sections of non-oriented silicon steel core, the upper and lower sections of the non-oriented silicon steel core are symmetrically arranged, the width of the middle section of the non-oriented silicon steel core is smaller than that of the upper and lower sections of the non-oriented silicon steel core, and the edges of the three sections of the non-oriented silicon steel core are spliced ​​together to form an inwardly concave arc structure.

[0011] Compared with the prior art, the technical solution of the present invention not only improves the overall technical solution, but also includes many improvements in details. Specifically, it has the following beneficial effects:

[0012] 1. The improved scheme of the present invention comprises a stator body including an annular stator core matrix and a stator core insert arranged on the end surface of the annular stator core matrix, the annular stator core matrix is ​​formed by nesting an oriented silicon steel core and a non-oriented silicon steel core, and the stator core insert is a non-oriented silicon steel core, which reduces the magnetic leakage of the teeth, reduces the magnetic flux pulsation in the air gap, and improves the performance of the motor;

[0013] 2. In the technical solution of the present invention, a through hole is opened at the bottom of the stator slot to saturate the magnetic field around the through hole, so as to prevent the magnetic lines of force generated by the oriented silicon steel core of the stator teeth from entering the oriented silicon steel core of the stator yoke;

[0014] 3. The N-pole magnetic steel and the S-pole magnetic steel of the present invention are staggered on the rotor back iron, so that the magnetic steel polarities of the left and right rotors are the same, and the structure is an NN topology structure, so that the motor has higher torque density and efficiency;

[0015] 4. The present invention has a reasonable structural design and proper layout. The stator is wound by oriented and non-oriented silicon steel sheets, which reduces the performance damage caused by process problems in the process of punching sheets into iron cores, reduces production costs, and is easy to promote and utilize. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the prior art.

[0017] Figure 2 It is a structural schematic diagram of the present invention.

[0018] Figure 3 It is a structural schematic diagram of an embodiment of the present invention.

[0019] Figure 4 It is a schematic diagram of the structure of the annular stator core matrix of the present invention.

[0020] Figure 5 This is a schematic diagram of the structure of the annular non-oriented silicon steel core of the present invention.

[0021] Figure 6 It is a schematic diagram of the structure of the annular oriented silicon steel core of the present invention.

[0022] Figure 7 for Figure 4 A magnified schematic diagram of part A.

[0023] Figure 8 It is a schematic diagram of the structure of the stator core insert of the present invention.

[0024] Fig. 9 It is a schematic structural diagram of the oriented silicon steel strip of the present invention.

[0025] Reference numerals:

[0026] 1 rotor back plate, 2 permanent magnet, 3 stator core matrix, 4 stator winding, 5 stator yoke;

[0027] 31 annular oriented silicon steel core, 32 annular non-oriented silicon steel core, 33 stator core insert;

[0028] 51 through holes;

[0029] 311 stator slot, 312 small dovetail slot;

[0030] 321 large dovetail groove. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention provides a permanent magnet axial flux motor, see Figure 1, including a casing, and a stator and a rotor arranged in the casing. The difference between the invention and the prior art lies in that: the rotor includes a rotor back iron 1 and a magnetic steel arranged on the rotor back iron, and the stator includes a stator body and a stator winding 4 arranged on the stator body; the stator body includes an annular stator core matrix 3 and a stator core insert 33 arranged on the end surface of the annular stator core matrix 3, the annular stator core matrix is ​​formed by nesting an oriented silicon steel core and a non-oriented silicon steel core, and the stator core insert is a non-oriented silicon steel core.

[0033] In the technical solution of the present invention, the iron loss of the oriented steel strip in the rolling direction is only 1 / 3 of that in the transverse direction, and the ratio of magnetic permeability is 6:1. Its iron loss is about 1 / 2 of that of the hot-rolled strip, and its magnetic permeability is 2.5 times that of the hot-rolled strip. In order to achieve a higher salient pole ratio of the drive motor, when designing the drive motor, oriented silicon steel laminations with higher magnetic permeability are used in the polarization direction of the rotor instead of non-oriented silicon steel laminations, and oriented silicon steel laminations are also used in the stator pole shoes, which effectively reduces the iron loss and improves the salient pole ratio of the motor. At the same time, the multi-end annular core is conveniently and quickly connected with the I-shaped core insert, and the oriented and non-oriented punching sheets are wound and formed, which reduces the performance damage caused by process problems in the process of punching sheets into the core.

[0034] In one embodiment, the stator is composed of an annular stator core matrix and a stator core insert arranged on the end surface of the annular stator core matrix; a stator winding is wound around each stator core insert; the annular stator core matrix is ​​wound by non-oriented silicon steel sheets, and the stator core insert is wound by oriented silicon steel sheets.

[0035] Specifically, the annular stator core matrix is ​​composed of a group of annular oriented silicon steel cores symmetrically arranged in the upper and lower directions and an annular non-oriented silicon steel core arranged between the upper and lower annular oriented silicon steel cores. The iron loss of the oriented steel strip in the rolling direction is only 1 / 3 of that in the transverse direction, and the ratio of magnetic permeability is 6:1. Its iron loss is about 1 / 2 of that of the hot-rolled strip, and its magnetic permeability is 2.5 times that of the hot-rolled strip. Therefore, in order to provide the magnetic energy product in the main magnetic circuit, a unique method of combining two cores is used to make the stator. The stator is made of a non-oriented silicon steel core and an oriented silicon steel core nested together. Oriented silicon steel is used as the stator teeth of the motor, and non-oriented silicon steel is used as the stator yoke. The stator teeth and part of the yoke iron core are wound with oriented silicon steel sheets, and through holes are opened on the steel strip at the bottom of the slot to saturate the magnetic field around the through holes, thereby preventing the magnetic lines of force of the teeth from entering the oriented steel strip at the yoke at the bottom of the slot. The width of the steel strip at the yoke at the bottom of the slot has sufficient strength after the through holes are removed. In addition, due to the low tangential magnetic permeability of oriented silicon steel, local saturation is further caused at the through holes, thereby reducing leakage magnetic flux and increasing the magnetic energy product in the main magnetic circuit.

[0036] The yoke core is wound with non-oriented silicon steel sheets, and the magnetic steel is bonded to the rotor back iron surface with N and S poles staggered. There are 2p permanent magnets fixed on the rotor surface. In the axial direction of the motor, the magnetic steel polarities on the left and right rotors are the same. The motor has 2p rotating magnetic fields, and the material utilization rate of the stator core yoke is high. This structure is an NN topology. For the single-stator dual-rotor NN topology, the material utilization rate of the stator core is higher than that of the NS topology, and the motor has higher torque density and efficiency.

[0037] In another embodiment, the present invention utilizes the material characteristics of oriented silicon steel to reduce the magnetic resistance of the magnetic circuit, increase the air gap magnetic energy product, and improve the output torque and efficiency of the motor; two oriented silicon steel core winding methods are beneficial to the material being made into an iron core (the oriented silicon steel sheet has a high magnetic permeability in the rolling direction, and the rolling direction is also called the longitudinal direction, which is the length direction of the silicon steel sheet; the transverse direction is the width direction of the steel strip, and the current widest length of the steel strip is about 1 meter. The disc motor cores are all wound, so oriented silicon steel is difficult to make a disc core structure. This solution adopts a first-line connection method to connect multiple sections of oriented steel strips together and wind them into shape), improve material utilization, and give full play to the advantage of higher magnetic permeability in the rolling direction; the magnetic slot wedge and oriented silicon steel are integrated into a design to reduce tooth leakage, reduce magnetic flux pulsation in the air gap, and improve motor performance.

[0038] Specifically, in an axial flux single-stator dual-rotor oriented disc motor (see Figure 3 ), number 1 is the rotor back iron; 2 is the permanent magnet; 31 is the annular oriented silicon steel core, 32 is the annular non-oriented silicon steel core, 33 is the stator core insert; 4 is the coil winding. The permanent magnet is glued to the rotor back iron or bolted to the rotor back iron. Stator coils are wound around each slot of the oriented silicon steel core; the upper and lower oriented silicon steel cores are connected by an I-shaped non-oriented silicon steel core and an annular non-oriented silicon steel core disc.

[0039] The annular oriented silicon steel core is provided with a stator slot, which divides the annular oriented silicon steel core into stator teeth. The bottom of the stator slot (partially oriented silicon steel core) together with the annular non-oriented silicon steel core form a stator yoke. A through hole is provided at the bottom of the stator slot to prevent the magnetic lines of force generated by the oriented silicon steel core of the stator teeth from entering the oriented silicon steel core of the stator yoke. Because the through hole is provided, the passage of the magnetic lines of force can be interrupted. Further, in order to ensure the blocking effect, multiple through holes can be provided here. In this embodiment, 3 through holes are provided. The three through holes can be arranged in parallel, and the spacing between the parallel arrangements is 0.5-1.5mm. The distance between the through holes and the upper and lower sides of the bottom of the stator slot is 2-4.5mm. The three through holes can also be staggered up and down. The advantage of the staggered arrangement is that the passage of the magnetic lines of force is more cut off, reducing the occurrence of magnetic leakage in the teeth. The shape of the through hole can be square, circular, or polygonal. Selecting a square slot can minimize the magnetic circuit area of ​​the magnetic bridge at the bottom of the slot, reduce the mass of the motor core, and improve the power density of the motor.

[0040] A large dovetail groove is provided on the surface of the annular non-oriented silicon steel core, and a small dovetail groove is provided below the opening. The large and small dovetail grooves are combined to form an I-shaped groove, where the area ratio of the large and small dovetail grooves is 1:0.2--0.3. A stator core insert is provided in the I-shaped slot, and the stator core insert is an I-shaped non-oriented silicon steel core. The I-shaped core insert is placed in the large and small dovetail grooves. This dovetail groove structure not only ensures a higher overall fit between the stator core insert and the rest of the annular stator core matrix, but also further ensures the combination and overall performance of the two when the motor is running at a high rotation speed. I-shaped core inserts are used here because they are easy to process, have a simple and reliable structure, have magnetic conductivity, and can reduce the magnetic resistance of the yoke magnetic circuit. The large dovetail groove is the main magnetic circuit path of the yoke, and the gap between the punching sheets in the magnetic circuit should be minimized as much as possible, because the magnetic properties will be damaged after the punching sheets are punched out. The small dovetail groove mainly serves as a connection and fixation, and should be as small as possible while ensuring strength.

[0041] Furthermore, the total length of the through holes is smaller than the bottom width of the stator slots, which can guide the passage of magnetic lines of force. The stator slots are flat-bottomed slots.

[0042] Two symmetrically arranged left and right rotors are provided, the stator is arranged between the two rotors, and the N-pole magnetic steel and the S-pole magnetic steel are alternately arranged on the rotor back iron, so that the magnetic steel polarities of the left and right rotors are the same.

[0043] The I-shaped non-oriented silicon steel core is spliced ​​by upper, middle and lower sections of non-oriented silicon steel core. The upper and lower sections of the non-oriented silicon steel core are symmetrically arranged, the width of the middle section of the non-oriented silicon steel core is smaller than that of the upper and lower sections of the non-oriented silicon steel core, and the edges of the three sections of the non-oriented silicon steel core are spliced ​​to form an inwardly concave arc structure.

[0044] The invention has reasonable structural design and proper layout. The stator is wound by oriented and non-oriented silicon steel sheets, which reduces the performance damage caused by process problems in the process of punching sheets into iron cores, reduces production costs, and is easy to promote and utilize.

[0045] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to the above descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A permanent magnet axial flux motor, comprising a housing, and a stator and a rotor arranged in the housing, characterized in that: The rotor includes a rotor back iron and a magnetic steel arranged on the rotor back iron, and the stator includes a stator body and a stator winding arranged on the stator body; the stator body includes an annular stator core matrix and a stator core insert arranged on the end surface of the annular stator core matrix, the annular stator core matrix is ​​formed by nesting an oriented silicon steel core and a non-oriented silicon steel core, and the stator core insert is a non-oriented silicon steel core; The annular stator core matrix comprises a group of annular oriented silicon steel cores symmetrically arranged at the upper and lower parts and an annular non-oriented silicon steel core arranged between the upper and lower annular oriented silicon steel cores; The annular oriented silicon steel core is provided with stator slots, which divide the annular oriented silicon steel core into stator teeth. The bottom of the stator slots together with the annular non-oriented silicon steel core form a stator yoke. A through hole is provided at the bottom of the stator slot to prevent the magnetic lines of force generated by the oriented silicon steel core of the stator teeth from entering the oriented silicon steel core of the stator yoke. A large dovetail groove is provided on the surface of the annular non-oriented silicon steel core, and a small dovetail groove is provided below the opening. The area ratio of the large dovetail groove to the small dovetail groove is 1:0.2-0.

3. The large and small dovetail grooves are combined to form an I-shaped groove. A stator core insert is provided in the I-shaped groove. The stator core insert is an I-shaped non-oriented silicon steel core.

2. A permanent magnet axial flux motor according to claim 1, characterized in that: The through holes are a plurality of parallel square slots, the total length of the through holes is smaller than the slot bottom width of the stator slot, and the stator slot is a flat-bottom slot.

3. A permanent magnet axial flux motor according to claim 1, characterized in that: Two symmetrically arranged left and right rotors are provided, the stator is arranged between the two rotors, and the N-pole magnetic steel and the S-pole magnetic steel are alternately arranged on the rotor back iron, so that the magnetic steel polarities of the left and right rotors are the same.

4. A permanent magnet axial flux motor according to claim 1, characterized in that: The I-shaped non-oriented silicon steel core is spliced ​​by upper, middle and lower sections of non-oriented silicon steel core. The upper and lower sections of the non-oriented silicon steel core are symmetrically arranged, the width of the middle section of the non-oriented silicon steel core is smaller than that of the upper and lower sections of the non-oriented silicon steel core, and the edges of the three sections of the non-oriented silicon steel core are spliced ​​to form an inwardly concave arc structure.

Images