Synchronous reluctance motor

Abstract

The present application provides a synchronous reluctance motor. The synchronous reluctance motor comprises a stator core (1) and a rotor core (2), wherein the stator core (1) comprises stator teeth (3), and the rotor core (2) comprises a plurality of magnetic barrier groups arranged along the circumferential direction, each magnetic barrier group comprises a plurality of magnetic flux barriers (4) arranged at intervals along the radial direction, and a magnetic conductive channel (5) is formed between adjacent magnetic flux barriers (4) under the same pole, wherein the number of stator teeth N is s 、Number of flux barriers under each pole B s and the number of rotor poles 2p have the following relationship: N s / 2p=B s +1. The synchronous reluctance motor according to the present application can effectively reduce torque pulsation and improve motor performance.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a synchronous reluctance motor. Background Art

[0002] Industrial motors are widely used in fans, pumps, general machinery and other fields. The industry consumes more than 800 billion kWh of electricity, and has great energy-saving potential. At present, IE2 asynchronous motors are still the main ones, which are low in efficiency, large in size and complex in process. Permanent magnet synchronous motors (IPM) can achieve IE4 or above energy efficiency in some high-efficiency occasions, but high-performance permanent magnets usually contain rare earth components, which makes it difficult to save energy and reduce costs.

[0003] With the continuous advancement of electromagnetic and control technology, the synchronous reluctance motor without permanent magnets and simple process has become the new favorite in the research of removing permanent magnets from synchronous motors. However, since the synchronous reluctance motor has no permanent magnets and the rotor structure has a multi-layer flux barrier structure, the means to suppress torque pulsation and the design difficulty are relatively large. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a synchronous reluctance motor that can effectively reduce torque pulsation and improve motor performance.

[0005] In order to solve the above problems, the present application provides a synchronous reluctance motor, including a stator core and a rotor core, the stator core includes stator teeth, the rotor core includes a plurality of magnetic barrier groups arranged along the circumferential direction, each magnetic barrier group includes a plurality of magnetic flux barriers arranged at intervals along the radial direction, and a magnetic conductive channel is formed between adjacent magnetic flux barriers under the same pole, wherein the number of stator teeth N s 、Number of flux barriers under each pole B s The relationship between N and the number of rotor poles 2p is as follows: s / 2p=B s +1.

[0006] Preferably, the magnetic flux barrier of the same pole includes a first portion extending in a tangential direction of the rotor core and second portions located at both ends of the first portion, and the second portion is bent radially outward relative to the first portion.

[0007] Preferably, in a cross section perpendicular to the central axis of the rotor core, the extension lines of the two side walls of the second portion of each flux barrier intersect with the outer circumference of the rotor core to form a type A point close to the Q axis and a type B point far from the Q axis.

[0008] Preferably, the angle formed by the line connecting the two Class A points of the magnetic flux barrier located at the radially outermost side of the rotor core under the same pole and the central axis of the rotor core is A0, where 0.27 <A0 / (π / p)<0.3。

[0009] Preferably, under the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core are A 1-2 , A 2-3 , ... A (N-1)-N The angles formed by the lines connecting two adjacent type B points and the central axis of the rotor core are B 1-2 , B 2-3 , ... B (N-1)-N , where |A (i-1)-i / B (i-1)-i -1|<0.03, i=2, 3...N.

[0010] Preferably, under the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core are A 1-2 , A 2-3 , ... A (N-1)-N , where |A (i-2)-(i-1) / A (i-1)-i -1|<0.18, i=3, 4...N.

[0011] Preferably, the maximum position of the salient pole difference of the rotor core under the same pole is located on the angular bisector between the Q axis and the D axis under the pole, where the salient pole difference is L d -L q , L d is the D-axis inductance, L q is the Q-axis inductance.

[0012] Preferably, along the radially inward direction, the radial thickness of the first portion of the flux barrier is sinusoidally distributed.

[0013] Preferably, a Class C point is provided between Class A point and Class B point located on the same side of the Q axis under the same pole, and the Class C point is located at the midpoint of the circumferential segment between the Class A point and the Class B point at the end of each magnetic channel. Along the direction away from the Q axis, the line between the Class C point and the central axis of the rotor core and the angular bisector of the Q axis and the D axis successively form angles α1α2…α N , along the radial inward direction, the radial thickness of the first part of the flux barrier is W1, W2...W N ,in

[0014]

[0015] i=2, 3…N, a is the adjustment margin.

[0016] Preferably, the second part includes a first bending section connected to the first part and a second bending section located at an end of the second part away from the first part. In a cross section perpendicular to the central axis of the rotor core, two endpoints at the end of the second bending section of each magnetic flux barrier intersect with the outer circumference of the rotor core to form a Class A point close to the Q axis and a Class B point away from the Q axis, wherein the distance between the intersection point of each endpoint with the outer circumference of the rotor core is the minimum distance between the endpoint and the outer circumference of the rotor core.

[0017] The synchronous reluctance motor provided by the present application comprises a stator core and a rotor core, wherein the stator core comprises stator teeth, and the rotor core comprises a plurality of magnetic barrier groups arranged circumferentially, each magnetic barrier group comprises a plurality of magnetic flux barriers arranged radially at intervals, and a magnetic conductive channel is formed between adjacent magnetic flux barriers under the same pole, wherein the number of stator teeth N is s 、Number of flux barriers under each pole B s The relationship between N and the number of rotor poles 2p is as follows: s / 2p=B s +1. There is a correlation between the number of stator teeth, the number of flux barrier layers and the number of rotor poles, which affects the working performance of the motor. Through the topological study of the optimal number of stator teeth and the number of rotor magnetic channel layers, the relationship between the three is limited to the above formula, and the number of stator teeth, the number of flux barriers and the number of rotor poles can be reasonably set, thereby reducing the torque pulsation of the motor, suppressing the torque pulsation of the synchronous reluctance motor at a lower level, reducing the motor rotation noise and improving the motor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a synchronous reluctance motor according to an embodiment of the present application;

[0019] Figure 2 This is a schematic diagram of the first size structure of the synchronous reluctance motor according to an embodiment of the present application;

[0020] Figure 3 A schematic diagram of the second size structure of the synchronous reluctance motor according to an embodiment of the present application;

[0021] Figure 4 A diagram showing the distribution structure of type A points and type B points of the synchronous reluctance motor of the first embodiment of the present application;

[0022] Figure 5 A diagram showing the distribution structure of type A points and type B points of the synchronous reluctance motor of the second embodiment of the present application;

[0023] Figure 6 1 is a torque curve comparison diagram of the synchronous reluctance motor according to the embodiment of the present application and the synchronous reluctance motor according to the prior art.

[0024] The reference numerals are:

[0025] 1. Stator core; 2. Rotor core; 3. Stator teeth; 4. Magnetic flux barrier; 5. Magnetic channel; 6. First part; 7. Second part; 8. First bending section; 9. Second bending section. DETAILED DESCRIPTION

[0026] See also Figures 1 to 6 As shown, according to an embodiment of the present application, the synchronous reluctance motor includes a stator core 1 and a rotor core 2, the stator core 1 includes stator teeth 3, the rotor core 2 includes a plurality of magnetic barrier groups arranged along the circumferential direction, each magnetic barrier group includes a plurality of magnetic flux barriers 4 arranged radially at intervals, and a magnetic conductive channel 5 is formed between adjacent magnetic flux barriers 4 under the same pole, wherein the number of stator teeth N s 、Number of flux barriers under each pole B s The relationship between N and the number of rotor poles 2p is as follows: s / 2p=B s +1.

[0027] There is a correlation between the number of stator teeth, the number of flux barrier layers and the number of rotor poles, which affects the working performance of the motor. This application limits the relationship between the three to the above formula through the topological study of the optimal number of stator teeth and the number of rotor magnetic channels. The number of stator teeth, the number of flux barriers and the number of rotor poles can be reasonably set, so that the number of stator teeth, the number of flux barriers and the number of rotor poles can be reasonably matched, thereby reducing the motor torque pulsation, suppressing the torque pulsation of the synchronous reluctance motor at a lower level, reducing the motor rotation noise, and improving the motor performance. By adopting the above scheme, the torque fluctuation of the synchronous reluctance motor can be maintained below 10% as a whole.

[0028] Through the study of the rotor topology structure, it was found that the torque pulsation based on the matching of the number of stator teeth, the number of rotor poles, and the number of flux barrier layers can achieve a smaller torque pulsation level than that of motors with other structural matching, such as 24-slot 4-pole 5-layer flux barrier, 36-slot 6-pole 5-layer flux barrier, 48-slot 6-pole 7-layer flux barrier, etc.

[0029] In this embodiment, the stator core 1 includes a rotor accommodating cavity, the rotor core 2 is arranged in the rotor accommodating cavity, and can rotate relative to the central axis of the stator core 1, and there is an air gap between the inner circumference of the stator core 1 and the outer circumference of the rotor core 2. The inner circumference of the stator core 1 has a plurality of stator teeth 3 and stator slots uniformly arranged along the circumferential direction.

[0030] No permanent magnets are arranged on the rotor core 2. A plurality of air slots are hollowed out on a magnetic conductive material disk to form a magnetic flux barrier 4. Magnetic conductive channels 5 are formed between adjacent magnetic flux barriers. Multiple magnetic flux barriers 4 and magnetic conductive channels 5 are alternately arranged radially to form a pole. An even number of poles are evenly distributed along the circumference.

[0031] The flux barriers 4 of the same pole include a first portion 6 extending tangentially along the rotor core 2 and second portions 7 located at both ends of the first portion 6, and the second portions 7 are bent radially outward relative to the first portion 6. By providing the bent portions, the difference between the direct-axis inductance and the quadrature-axis inductance can be increased, thereby increasing the saliency ratio and improving the operating performance of the synchronous reluctance motor.

[0032] Preferably, in a cross-section perpendicular to the central axis of the rotor core 2, the extension lines of the two side walls of the second portion 7 of each flux barrier 4 intersect with the outer circumference of the rotor core 2, forming a type-A point close to the Q-axis and a type-B point far from the Q-axis.

[0033] The flux barriers 4 on the rotor core 2 are sequentially defined as flux barrier a1, flux barrier a2... flux barrier a along the direction from the outside to the inside in the radial direction. N Among them, each flux barrier 4 has a first portion 6 that is horizontally tangential and a second portion 7 that is bent radially. The portion of the second portion 7 that is bent radially and is close to the rotor circumferential side is the end of the flux barrier, and this end is not connected to the air gap and has a thin-wall structure distributed tangentially, forming a tangential rib. The tangential rib is formed by the intersection of the extension lines of the two side walls of the second portion 7 with the outer circumference of the rotor core 2. Generally, the thickness of this rib is 0.3 - 1.0 mm. Two marking points are formed on the outer circumference of the rotor core 2 at both ends of each rib. Among them, those close to the pole axis Qaxis under each pole are collectively referred to as type-A points, and those far from the Qaxis are collectively referred to as type-B points.

[0034] In this embodiment, each of the above-mentioned tangential ribs has 1 type-A point and 1 type-B point. Among them, the angle presented by the type-A points of the flux barrier a1 and the flux barrier a2 on the same side of the Q-axis under the same pole with the center of the rotor core 2 as the origin is A 1-2 The angle presented by the type-A points of the flux barrier a2 and the flux barrier a3 with the center of the rotor core 2 as the origin is A 2-3 The angle presented by the type-B points of the flux barrier a1 and the flux barrier a2 with the center of the rotor core 2 as the origin is B 1-2 The angle presented by the type-B points of the flux barrier a2 and the flux barrier a3 with the center of the rotor core 2 as the origin is B 2-3 …

[0035] Preferably, for the flux barrier 4 located at the outermost side in the radial direction of the rotor core 2 under the same pole, the included angle formed by the connection lines between the two type-A points on both sides of the Q-axis and the central axis of the rotor core 2 is A0, where 0.27 < A0 / (π / p) < 0.3. At this time, the motor torque output can be maintained at a relatively high level.

[0036] When A0 / (π / P) is less than 0.27, the span of the outermost magnetic channel 5 is too small to effectively utilize the magnetic pull to generate the magnetic resistance torque. When A0 / (π / p) is greater than 0.3, the span of the outermost magnetic channel 5 is too large, which not only squeezes the structural space of the remaining layers of the magnetic channel 5, but also the increased span does not generate effective magnetic resistance torque.

[0037] At the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core 2 are A 1-2 , A 2-3 , ... A (N-1)-N The angles formed by the lines connecting two adjacent type B points and the central axis of the rotor core 2 are B 1-2 , B 2-3 , ... B (N-1)-N , where |A (i-1)-i / B (i-1)-i -1|<0.03, i=2, 3...N.

[0038] The angles formed by the A-type points and the B-type points of any two adjacent end ribs of the flux barrier 4 are close, and the angle difference is within 3%. As follows:

[0039] |A 1-2 / B 1-2 -1|<0.03

[0040] |A 2-3 / B 2-3 -1|<0.03

[0041] …

[0042] |A (N-1)-N / B (N-1)-N -1|<0.03

[0043] Combined with the rotor structure, it can be found that, through the restriction of the above formula, the angles of the ends of the adjacent magnetic channels 5 of each layer are basically the same and maintained within a small fluctuation range. Since the stator slots are evenly distributed and the width of each slot is fixed, the rotor adopts the same design principle as the stator slot, which is conducive to avoiding the generation of torque pulsation harmonics caused by inconsistent rotor slot structures.

[0044] At the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core 2 are A 1-2 , A 2-3 , ... A (N-1)-N , where |A (i-2)-(i-1) / A (i-1)-i -1|<0.18, i=3, 4...N.

[0045] When the rotor rotates counterclockwise, there is a certain difference in the angles of the A-type points of the adjacent flux barrier end ribs, and the ratio difference is in the range of 0.1 to 0.18 to obtain the minimum torque pulsation.

[0046] 0.1<|A 1-2 / A 2-3 -1|<0.18

[0047] 0.1<|A 2-3 / A 3-4 -1|<0.18

[0048] …

[0049] 0.1<|A (N-2)-(N-1) / A (N-1)-N -1|<0.18

[0050] Based on the design of basically the same opening angle at the end of the rotor flux barrier, the width of the end of each magnetic channel 5 is equivalently adjusted through the restriction of the above formula, so as to adjust the phase difference of each magnetic channel 5 when generating the magnetic resistance torque, so that each magnetic channel of the rotor can achieve staggered output and suppress torque pulsation.

[0051] Through the above design, the angles of the ends of adjacent magnetic channels 5 in each layer can be basically the same and maintained within a small fluctuation range. Since the stator slots are evenly distributed and the width of each slot is fixed, when the rotor slots adopt the same design principle as the stator slots, it is beneficial to avoid the generation of torque pulsation harmonics caused by inconsistent rotor slot structures.

[0052] Due to the existence of the rotor notch, the continuous outer circle becomes notched. Taking gears as an analogy, for example, if the stator notch forms a gear, then the rotor notch matches the structure formed by the stator notch to better mesh, so that the output torque is more stable.

[0053] By defining the end angles of each magnetic channel 5 through the above three formulas, the torque pulsation can be suppressed to a level of 4% to 5% while ensuring the torque output.

[0054] The maximum position of the salient pole difference of the rotor core 2 under the same pole is located on the angular bisector between the Q axis and the D axis under the pole, where the salient pole difference is L d -L q , L d is the D-axis inductance, L q is the Q-axis inductance.

[0055] Motor torque output formula:

[0056]

[0057] Where T e is the electromagnetic torque; p is the number of motor poles; L d is the D-axis inductance; L q is the Q-axis inductance; θ is the torque control angle

[0058] When θ is 45° (electrical angle), the sin(2θ) variable can reach the maximum value. Therefore, in the structural design, the salient pole difference L d -L q The position is designed to be on the angular bisector of Qaxis and Daxis to maximize the torque. By designing the magnetic channel to have a roughly sinusoidal distribution structure, which matches the magnetic field distribution, it is helpful to alleviate magnetic circuit saturation and improve the output torque. Therefore, along the radial inward direction, the radial thickness of the first part 6 of the tangential horizontal rotor magnetic channel 5 has the characteristics of a sinusoidal distribution. Through this design, the optimal torque control angle on the rotor structure can be controlled to 45° (electrical angle). W1 is the thickness of the first layer of the magnetic channel, and W6 is the thickness of the sixth layer of the magnetic channel.

[0059] The above design can alleviate the magnetic circuit saturation, which is equivalent to increasing L d The inductance value is increased, so the salient pole difference is increased, thereby improving the motor performance.

[0060] The magnetic conductive channel 5 under the same pole has a type C point between the type A point and the type B point on the same side of the Q axis. The type C point is located at the midpoint of the circumferential segment between the type A point and the type B point at the end of each magnetic conductive channel 5. Along the direction away from the Q axis, the line between the type C point and the central axis of the rotor core 2 and the angular bisector of the Q axis and the D axis successively form angles α1 α2 … α N , along the radial inward direction, the radial thickness of the first portion 6 of the flux barrier 4 is W1, W2...W N ,in

[0061]

[0062] i=2, 3…N, a is the adjustment margin.

[0063] The above-mentioned a is, for example, 5, and a% is a margin for appropriately adjusting the thickness ratio of the first portion 6 of the flux barrier 4 according to issues such as spatial arrangement.

[0064] Based on the design of basically the same opening angle at the end of the rotor flux barrier, the width of the end of each magnetic channel is equivalently optimized, so that the phase difference of each magnetic channel 5 is adjusted when generating the reluctance torque, so that the torque can achieve peak-valley complementary effect, and each magnetic channel 5 of the rotor can achieve staggered output, effectively suppressing torque pulsation.

[0065] Figure 6 The thick line in the figure is the torque curve of the synchronous reluctance motor of the present application, and the thin line is the torque curve of the synchronous reluctance motor in the prior art. It can be seen from the figure that the torque pulsation of the synchronous reluctance motor of the present application is greatly reduced compared with the prior art.

[0066] Preferably, in another embodiment of the present application, the second part 7 includes a first bending section 8 connected to the first part 6 and a second bending section 9 located at an end of the second part 7 away from the first part 6, and in a cross section perpendicular to the central axis of the rotor core 2, two endpoints at the end of the second bending section 9 of each flux barrier 4 intersect with the outer circumference of the rotor core 2 to form a Class A point close to the Q axis and a Class B point away from the Q axis, wherein the distance between the intersection point of each endpoint with the outer circumference of the rotor core 2 is the minimum distance between the endpoint and the outer circumference of the rotor core 2.

[0067] In this embodiment, although there are at least two bends on the two arm structures of the magnetic channel 5, the point that divides each magnetic channel is still the end of the thin-walled structure, and the effective part of the rib is the part of the thin-walled structure with equal thickness, or the point where the part begins to change when expanding circumferentially from the thinnest part to both ends. Therefore, it can still be applied to the above-mentioned division of Class A points and Class B points, so that the design of the flux barrier 4 can meet the limitations of the above-mentioned formula, ensuring that the opening angles of the rotor flux barrier ends are basically the same.

[0068] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0069] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A synchronous reluctance motor, characterized in that: The invention comprises a stator core (1) and a rotor core (2), wherein the stator core (1) comprises stator teeth (3), and the rotor core (2) comprises a plurality of magnetic barrier groups arranged in the circumferential direction, each of the magnetic barrier groups comprises a plurality of magnetic flux barriers (4) arranged in radial intervals, and a magnetic conductive channel (5) is formed between adjacent magnetic flux barriers (4) under the same pole, wherein the number of stator teeth N is s 、Number of flux barriers under each pole B s The relationship between N and the number of rotor poles 2p is as follows: s / 2p=B s +1; The magnetic flux barrier (4) of the same pole comprises a first portion (6) extending in a tangential direction of the rotor core (2) and a second portion (7) located at both ends of the first portion (6), wherein the second portion (7) is bent radially outward relative to the first portion (6); In a cross section perpendicular to the central axis of the rotor core (2), the extension lines of the two side walls of the second part (7) of each of the magnetic flux barriers (4) intersect with the outer circumference of the rotor core (2), forming a type A point close to the Q axis and a type B point far from the Q axis; The angle formed by the line connecting the two type A points of the magnetic flux barrier (4) located at the radially outermost side of the rotor core (2) under the same pole and the central axis of the rotor core (2) is A0, where 0.27 <A0 / (π / p)<0.3。 2. The synchronous reluctance motor according to claim 1, characterized in that: At the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core (2) are A 1-2 , A 2-3 , ... A (N-1)-N The angles formed by the lines connecting two adjacent type B points and the central axis of the rotor core (2) are B 1-2 , B 2-3 , ... B (N-1)-N , where |A (i-1)-i / B (i-1)-i -1|<0.03, i=2, 3...N.

3. The synchronous reluctance motor according to claim 1, characterized in that: At the same pole, on the same side of the Q axis, in the direction away from the Q axis, the angles formed by the lines connecting two adjacent type A points and the central axis of the rotor core (2) are A 1-2 , A 2-3 , ... A (N-1)-N ,in A (i-2)-(i-1) / A (i-1)-i -1|<0.18,i=3、4……N。 4. The synchronous reluctance motor according to claim 1, characterized in that: The maximum position of the salient pole difference of the rotor core (2) under the same pole is located on the angular bisector between the Q axis and the D axis under the pole, where the salient pole difference is L d -L q , L d is the D-axis inductance, L q is the Q-axis inductance.

5. The synchronous reluctance motor according to claim 1, characterized in that: Along the radially inward direction, the radial thickness of the first portion (6) of the flux barrier (4) is sinusoidally distributed.

6. The synchronous reluctance motor according to claim 1, characterized in that: The magnetic conductive channel (5) under the same pole has a type C point between the type A point and the type B point located on the same side of the Q axis, and the type C point is located at the midpoint of the circumferential segment between the type A point and the type B point at the end of each magnetic conductive channel (5). Along the direction away from the Q axis, the line between the type C point and the central axis of the rotor core (2) and the angular bisector of the Q axis and the D axis successively form angles α1α2…α N , along the radial inward direction, the radial thickness of the first part (6) of the flux barrier (4) is W1, W2...W N ,in i=2, 3…N, a is the adjustment margin.

7. The synchronous reluctance motor according to claim 1, characterized in that: The second part (7) comprises a first bending section (8) connected to the first part (6) and a second bending section (9) located at an end of the second part (7) away from the first part (6). In a cross section perpendicular to the central axis of the rotor core (2), two endpoints at the end of the second bending section (9) of each magnetic flux barrier (4) intersect with the outer circumference of the rotor core (2) to form a type A point close to the Q axis and a type B point away from the Q axis, wherein the distance between the intersection point of each endpoint with the outer circumference of the rotor core (2) is the minimum distance between the endpoint and the outer circumference of the rotor core (2).

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